![]() Curable composition
专利摘要:
A curable composition including a fluorine-containing silane compound having two or more Si atoms each bonding to at least one group selected from the group consisting of a hydroxyl group and a hydrolyzable group, an organosilicon compound having at least two -ORg3(S) each bonding to a Si atom, wherein each Rg3, at each occurrence, independently represents a hydrogen atom or monovalent organic group, and a metal-based catalyst represented by M(-O-Rh)η, wherein: M represents a metal atom; each Rh, at each occurrence, independently represents a hydrocarbon group having 1 to 3 carbon atoms; and η is the coordination number of M. 公开号:EP3705530A1 申请号:EP18874427.0 申请日:2018-10-30 公开日:2020-09-09 发明作者:Yoshiaki Honda 申请人:Daikin Industries Ltd; IPC主号:C08L83-00
专利说明:
[0001] The present invention relates to a curable composition. Background Art [0002] A composition including a certain fluoropolyether-based compound has excellent water-repellency, oil-repellency, and the like. For example, Patent Literature 1 describes rubber where a cured film of a room temperature curing perfluoropolyether composition is formed on the surface of the rubber, and describes the following: there is provided rubber to which releaseability, solvent resistance, chemical resistance, weather resistance, water-repellency, oil-repellency, and the like are imparted. The composition of Patent Literature 1 includes a condensation promoter, and dibutyltin dimethoxide or dibutyltin laulyrate is used as a condensation promoter in Examples of the Literature. Citation ListPatent Literature [0003] Patent Literature 1: JP 2005-220361 A Summary of InventionTechnical Problem [0004] It, however, have found according to studies by the present inventor that the condensation promoter (catalyst) of Patent Literature 1, when used, may cause the degree of transparency of a cured product obtained by curing the composition to be low. An object of the present invention is to provide a composition suitable for formation of a cured product favorable in degree of transparency. Solution to Problem [0005] A first aspect of the present invention provides a curable composition includinga fluorine-containing silane compound having two or more Si atoms each bonding to at least one group selected from the group consisting of a hydroxyl group and a hydrolyzable group,an organosilicon compound having at least two -ORg3(s) each bonding to a Si atom, wherein each Rg3, at each occurrence, is independently a hydrogen atom or a monovalent organic group, anda metal-based catalyst represented by M(-O-Rh)η, wherein: M represents a metal atom; each Rh, at each occurrence, is independently a hydrocarbon group having 1 to 3 carbon atoms; and η is the coordination number of M. Advantageous Effects of Invention [0006] An object of the present invention is to provide a composition suitable for formation of a cured product favorable in degree of transparency. Description of Embodiments [0007] Hereinafter, the curable composition of the present invention will be described. [0008] The curable composition of the present invention includesa fluorine-containing silane compound having two or more Si atoms each bonding to at least one group selected from the group consisting of a hydroxyl group and a hydrolyzable group (hereinafter, sometimes referred to as "fluorine-containing silane compound"),an organosilicon compound having at least two -O-Rg3(s) each bonding to a Si atom, wherein each Rg3, at each occurrence, is independently a hydrogen atom or a monovalent organic group (hereinafter, sometimes referred to as "cross-linking agent"), anda metal-based catalyst represented by M(-O-Rh)η, wherein M represents a metal atom, each Rh, at each occurrence, is independently, a hydrocarbon group having 1 to 3 carbon atoms, and η is the coordination number of M. (Fluorine-containing silane compound) [0009] The fluorine-containing silane compound is not limited as long as the compound has a fluorine-containing portion imparting water-repellency and chemical proofness and a silane moiety imparting a binding ability to other substance. The fluorine-containing silane compound refers to a compound where at least one hydrogen atom bonding to a carbon atom is substituted with a fluorine atom. [0010] The fluorine-containing silane compound preferably further includes a perfluoro(poly)ether group. That is, the fluorine-containing silane compound is preferably a perfluoropolyether group-containing silane compound (hereinafter, also referred to as "PFPE-containing silane compound (A)"). The perfluoropolyether group here means a group where all hydrogen atoms of a polyether group are each substituted with a fluorine atom. [0011] The "hydrolyzable group", as used herein, means a group which can undergo a hydrolysis reaction, namely, means a group which can be removed from a main backbone of the compound by a hydrolysis reaction. Examples of the hydrolyzable group include -OR, -OCOR, -O-N=CR2, -NR2, -NHR and a halogen atom, wherein R represents a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, and -OR (namely, an alkoxy group) is preferable. Examples of R include unsubstituted alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a n-butyl group and an isobutyl group; and substituted alkyl groups such as a chloromethyl group. Among them, an alkyl group, in particular, an unsubstituted alkyl group is preferable, and a methyl group or an ethyl group is more preferable. The hydroxyl group is not limited, and may be generated by hydrolyzing the hydrolyzable group. Examples of the halogen atom can include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and in particular, a chlorine atom is preferable. [0012] Such a Si atom bonding to at least one group selected from the group consisting of a hydroxyl group and a hydrolyzable group is preferably present at each of both ends of a molecular backbone of the fluorine-containing silane compound (for example, PFPE-containing silane compound (A)). The molecular backbone of the fluorine-containing silane compound (for example, PFPE-containing silane compound (A)) here represents a relatively longest binding chain in a molecule of the fluorine-containing silane compound (for example, PFPE-containing silane compound (A)). [0013] The PFPE-containing silane compound (A) is preferably at least one compound represented by formula (A), (B), (C) or (D). [0014] Hereinafter, such any PFPE-containing silane compound (A) represented by formulae (A), (B), (C) and (D) will be described. [0015] The "di- to decavalent organic group", as used herein, means a di- to decavalent group containing carbon. The di- to decavalent organic group is not limited, and examples thereof include a di- to decavalent group where 1 to 9 hydrogen atoms are further removed from a hydrocarbon group. The divalent organic group is not limited, and examples thereof include a divalent group where one hydrogen atom is further removed from a hydrocarbon group. [0016] The "hydrocarbon group", as used herein, means a group which contains carbon and hydrogen and which is obtained by removing one hydrogen atom from a molecule. The hydrocarbon group is not limited, and examples thereof include a hydrocarbon group having 1 to 20 carbon atoms, optionally substituted with one or more substituents, such as an aliphatic hydrocarbon group and an aromatic hydrocarbon group. For example, the "aliphatic hydrocarbon group" may be any linear, branched or cyclic group, and may be any saturated or unsaturated group. For example, the hydrocarbon group may contain one or more ring structures. The hydrocarbon group may have one or more N, O, S, Si, amide, sulfonyl, siloxane, carbonyl, carbonyloxy, and the like at an end thereof or in a molecular chain thereof. [0017] Each substituent of the "hydrocarbon group", as used herein, is not limited, and examples thereof include a halogen atom; and one or more groups selected from a C1-6 alkyl group, a C2-6 alkenyl group, a C2-6 alkynyl group, a C3-10 cycloalkyl group, a C3-10 unsaturated cycloalkyl group, a 5 to 10-membered heterocyclyl group, a 5 to 10-membered unsaturated heterocyclyl group, a C6-10 aryl group and a 5 to 10-membered heteroaryl group each optionally substituted with one or more halogen atoms. [0018] The alkyl group and the phenyl group may be herein unsubstituted or substituted, unless particularly noted. Each substituent of such groups is not limited, and examples thereof include one or more groups selected from a halogen atom, a C1-6 alkyl group, a C2-6 alkenyl group and a C2-6 alkynyl group. [0019] In the formulae, PFPE, at each occurrence, is independently a group represented by: -(OC6F12)a-(OC5F10)b-(OC4F8)c-(OC3X10 6)d-(OC2F4)e-(OCF2)f-.In the formulae, a, b, c, d, e and f are each independently an integer of 0 or more and 200 or less, and the sum of a, b, c, d, e and f is at least 1. Preferably, a, b, c, d, e and f are each independently an integer of 0 or more and 100 or less. Preferably, the sum of a, b, c, d, e and f is 5 or more, more preferably 10 or more. Preferably, the sum of a, b, c, d, e and f is 200 or less, more preferably 100 or less, for example, 10 or more and 200 or less, more specifically 10 or more and 100 or less. The occurrence order of the respective repeating units in parentheses with a, b, c, d, e or f is not limited in the formula. Each X10, at each occurrence, independently represents a hydrogen atom, a fluorine atom or a chlorine atom, preferably a hydrogen atom or a fluorine atom, more preferably a fluorine atom. [0020] Such repeating units may, for example, be linear or branched, and are preferably linear. For example,-(OC6F12)- may be -(OCF2CF2CF2CF2CF2CF2)-,-(OCF(CF3)CF2CF2CF2CF2)-, -(OCF2CF(CF3)CF2CF2CF2)-,-(OCF2CF2CF(CF3)CF2CF2)-, -(OCF2CF2CF2CF(CF3)CF2)-,-(OCF2CF2CF2CF2CF(CF3))-, or the like, and is preferably-(OCF2CF2CF2CF2CF2CF2)-. For example, -(OC5F10)- may be-(OCF2CF2CF2CF2CF2)-, -(OCF(CF3)CF2CF2CF2)-,-(OCF2CF(CF3)CF2CF2)-, - (OCF2CF2CF(CF3)CF2)-,-(OCF2CF2CF2CF(CF3))-, or the like, and is preferably-(OCF2CF2CF2CF2CF2)-. -(OC4F8)- may be any of-(OCF2CF2CF2CF2)-, -(OCF(CF3)CF2CF2)-, -(OCF2CF(CF3)CF2)-,-(OCF2CF2CF(CF3))-, -(OC(CF3)2CF2)-, -(OCF2C(CF3)2)-,-(OCF(CF3)CF(CF3))-, -(OCF(C2F5)CF2)- and -(OCF2CF(C2F5))-, and is preferably -(OCF2CF2CF2CF2)-. -(OC3F6)- (namely, in the formulae, X10 represents a fluorine atom) may be any of -(OCF2CF2CF2)-, -(OCF(CF3)CF2)- and -(OCF2CF(CF3))-, and is preferably -(OCF2CF2CF2)-. -(OC2F4)- may be any of-(OCF2CF2)- and -(OCF(CF3))-, and is preferably -(OCF2CF2)-. [0021] In one embodiment, PFPE is -(OC3F6)d-, wherein d is an integer of 1 or more and 200 or less, preferably 5 or more and 200 or less, more preferably 10 or more and 200 or less. Preferably, PFPE is -(OCF2CF2CF2)d-, wherein d is an integer of 1 or more and 200 or less, preferably 5 or more and 200 or less, more preferably 10 or more and 200 or less, or -(OCF(CF3)CF2)d-, wherein d is an integer of 1 or more and 200 or less, preferably 5 or more and 200 or less, more preferably 10 or more and 200 or less. More preferably, PFPE is -(OCF2CF2CF2)d--, wherein d is an integer of 1 or more and 200 or less, preferably 5 or more and 200 or less, more preferably 10 or more and 200 or less. [0022] In another embodiment, PFPE is -(OC4F8)c-(OC3F6)d-(OC2F4)e-(OCF2)f-, wherein c and d are each independently an integer of 0 or more and 30 or less, e and f are each independently 1 or more and 200 or less, preferably 5 or more and 200 or less, more preferably an integer of 10 or more and 200 or less, the sum of c, d, e and f is at least 5 or more, preferably 10 or more, and the occurrence order of the respective repeating units in parentheses with the subscript c, d, e or f is not limited in the formulae. Preferably, PFPE is-(OCF2CF2CF2CF2)c-(OCF2CF2CF2)d-(OCF2CF2)e-(OCF2)f-. [0023] In one embodiment, PFPE may be -(OC2F4)e-(OCF2)f-, wherein e and f are each independently an integer of 1 or more and 200 or less, preferably 5 or more and 200 or less, more preferably 10 or more and 200 or less, and the occurrence order of the respective repeating units in parentheses with the subscript e or f is not limited in the formulae. The curable composition of the present invention, which includes the PFPE-containing silane compound (A), can contribute to formation of a cured product which can keep rubber properties even at a low temperature. [0024] In still another embodiment, PFPE is a group represented by -(R6-R7)j-. In the formulae, R6 represents OCF2 or OC2F4, preferably OC2F4. In the formula, R7 represents a group selected from OC2F4, OC3F6, OC4F8, OC5F10 and OC6F12, or a combination of two or three groups independently selected from the above groups. Preferably, R7 represents a group selected from OC2F4, OC3F6 and OC4F8, or a combination of two or three groups independently selected from the above groups, and is more preferably a group selected from OC3F6 and OC4F8. Such a combination of two or three groups independently selected from OC2F4, OC3F6 and OC4F8 is not limited, and examples thereof include -OC2F4OC3F6-, -OC2F4OC4F8-, -OC3F6OC2F4-, -OC3F6OC3F6-, -OC3F6OC4F8-, -OC4F8OC4F8-, -OC4F8OC3F6-, -OC4F8OC2F4-,-OC2F4OC2F4OC3F6-, -OC2F4OC2F4OC4F8-, -OC2F4OC3F6OC2F4-,-OC2F4OC3F6OC3F6-, -OC2F4OC4F8OC2F4-, -OC3F6OC2F4OC2F4-,-OC3F6OC2F4OC3F6-, -OC3F6OC3F6OC2F4-, and -OC4FBOC2F4OC2F4-, Here, j is an integer of 2 or more, preferably 3 or more, more preferably 5 or more, and an integer of 100 or less, preferably 50 or less. In the formulae, OC2F4, OC3F6, OC4F8, OC5F10 and OC6F12 may be linear or branched, and is preferably linear. In this embodiment, PFPE is preferably - (OC2F4-OC3F6)j- or -(OC2F4-OC4F8)j-. [0025] The ratio of e to f in PFPE (hereinafter, referred to as "e/f ratio") is 0.1 or more and 10 or less, preferably 0.2 or more and 5 or less, more preferably 0.2 or more and 2 or less, further preferably 0.2 or more and 1.5 or less. The e/f ratio, which falls within the range, can more enhance water-repellency, oil-repellency and chemical resistance (for example, durability to brine, aqueous acidic or basic solution, acetone, oleic acid or hexane) of a cured product obtained from the compound. A lower e/f ratio more enhances water-repellency, oil-repellency and chemical resistance of the cured product. On the other hand, an e/f ratio of 0.1 or more can more enhance stability of the compound. A higher e/f ratio more enhances stability of the compound. [0026] The e/f ratio may be less than 1.0, may be 0.10 or more, may be 0.20 or more, or may be 0.40 or more. The e/f ratio may be 0.90 or less, may be 0.85 or less, or may be 0.80 or less. The e/f ratio is, for example, 0.10 or more and less than 1.0, specifically 0.20 or more and 0.90 or less, more specifically 0.40 or more and 0.85 or less, further specifically 0.40 or more and 0.80 or less. [0027] The e/f ratio may be 1.0 or more, may be 1.1 or more, or may be 1.2 or more, and may be 10.0 or less, may be 5.0 or less, may be 2.0 or less, or may be 1.5 or less. The e/f ratio is, for example, 1.0 or more and 10.0 or less, specifically 1.0 or more and 5.0 or less, more specifically 1.0 or more and 2.0 or less, further specifically 1.0 or more and 1.5 or less. [0028] The temperature of 1% decomposition of a cured product of a curable composition where the e/f ratio is in the range can be a relatively high temperature. That is, such a curable composition can contribute to formation of a cured product usable in a wide temperature range. The "temperature of 1% decomposition" herein means a temperature at which 1% by mass of a cured product relative to the entire cured product is decomposed. The temperature of 1% decomposition means a value obtained by measurement according to thermogravimetric/differential thermal analysis (TG/DTA), and is specifically measured in the range from 25°C to 600°C at a temperature-increasing rate of 10°C/min under an oxygen atmosphere. Examples of the TG/DTA can include DTG-60 manufactured by Shimadzu Corporation. [0029] In one embodiment, the number average molecular weight of the -PFPE- moiety in the PFPE-containing silane compound (A) may be in the range from 2000 to 200000, or may be in the range from 3000 to 100000. The number average molecular weight is defined as a value obtained by 19F-NMR measurement. [0030] The number average molecular weight of the -PFPE-moiety in the PFPE-containing silane compound (A) is not limited, and is, for example, 500 to 30,000, preferably 1,500 to 30,000, more preferably 2,000 to 10,000. [0031] In another embodiment, the number average molecular weight of the -PFPE- moiety is 500 to 30,000, preferably 1,000 to 20,000, more preferably 2,000 to 15,000, still more preferably 2,000 to 10,000, and can be, for example, 3,000 to 6,000. [0032] In another embodiment, the number average molecular weight of the -PFPE- moiety can be 4,000 to 30,000, preferably 5,000 to 10,000, more preferably 6,000 to 10,000. [0033] In one embodiment, the number average molecular weight of the -PFPE- moiety can be in the range from 2,000 to 10,000, and is preferably in the range from 2,000 to 3,000. The compound can have such a number average molecular weight of the -PFPE- moiety to thereby allow the curable composition to be low in viscosity and be improved in handleability. The curable composition having such a number average molecular weight of the-PFPE- moiety, when, for example, used with a solvent to be formed into a solution, also has the advantage of suppression of the viscosity of such a solution. [0034] In one embodiment, the number average molecular weight of the -PFPE- moiety can be in the range from 10,000 to 100,000, and is preferably in the range from 10,000 to 50,000. The compound can have such a number average molecular weight of the -PFPE- moiety to thereby allow the curable composition to be improved in physical properties such as stretching properties after curing. [0035] In the formulae, each R13, at each occurrence, independently represents a hydroxyl group or a hydrolyzable group. The hydrolyzable group has the same meaning as described above. [0036] In the formulae, each R14, at each occurrence, independently represents a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms. [0037] In the formulae, each R11, at each occurrence, independently represents a hydrogen atom or a halogen atom. The halogen atom is preferably an iodine atom, a chlorine atom or a fluorine atom, more preferably a fluorine atom. [0038] In the formulae, each R12, at each occurrence, independently represents a hydrogen atom or a lower alkyl group. The lower alkyl group is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and examples thereof include a methyl group, an ethyl group and a propyl group. [0039] In the formulae, R11", R12", R13" and R14" have the same meanings as R11, R12, R13 and R14, respectively. [0040] In formula (A), such a Si atom bonding to at least one group selected from the group consisting of a hydroxyl group and a hydrolyzable group indicates a Si atom contained in (-SiR13 n1R14 3-n1) or (-SiR13" n1R14" 3-n1) where n1 is an integer of 1 to 3. [0041] In the formulae, n1 with respect to each (-SiR13 n1R14 3-n1) unit or each (-SiR13" n1R14" 3-n1) unit is independently an integer of 0 to 3, preferably 1 to 3, more preferably 3. In the formulae, at least two n1(s) are each an integer of 1 to 3, namely, there is not any case where all n1(s) are simultaneously 0. That is, at least two Si atoms each bonding to R13 or R13" are present in the formulae. In other words, at least two structures selected from the group consisting of a -SiR13 n1R14 3-n1 structure (namely,-SiR13 moiety) where n1 is 1 or more and a -SiR13" n1R14" 3-n1 structure (namely, -SiR13" moiety) where n1 is 1 or more are present in formula (A). [0042] Preferably, the Si atom bonding to at least one group selected from the group consisting of a hydroxyl group and a hydrolyzable group is present at both ends of a molecular backbone in formula (A). That is, at least one -SiR13 n1R14 3-n1 structure (namely, -SiR13 moiety) where n1 is 1 or more and at least one -SiR13" n1R14" 3-n1 structure (namely, -SiR13" moiety) where n1 is 1 or more are present in formula (A). [0043] In the formulae, each X1 independently represents a single bond or a di- to decavalent organic group. X1 is understood to be a linker which links a perfluoropolyether moiety (namely, -PFPE- moiety) mainly providing water-repellency, surface lubricity, and the like, and a silane moiety (namely, group in parentheses with α1) providing a binding ability to the base material, in any compound represented by formula (A). Accordingly, X1 may be a single bond or any organic group as long as such any compound represented by formula (A) can be stably present. Herein, a left portion and a right portion of the group designated as X1 are bonding to the group represented by PFPE and the group in parentheses with α1, respectively. [0044] In another embodiment, X1 can be Xe. Xe represents a single bond or a di- to decavalent organic group, preferably represents a single bond or a di- to decavalent organic group having at least one selected from the group consisting of -C6H4- (namely, -phenylene-, hereinafter, representing a phenylene group), -CO-(carbonyl group), -NR4- and -SO2-. Each R4 independently represents a hydrogen atom, a phenyl group, or a C1-6 alkyl group (preferably a methyl group), preferably represents a hydrogen atom or a methyl group. Such -C6H4-, -CO-, -NR4- or -SO2- is preferably contained in a molecular backbone of the PFPE-containing silane compound (A) . [0045] Xe more preferably represents a single bond or a di-to decavalent organic group having at least one selected from the group consisting of -C6H4-, -CONR4-, -CONR4-C6H4-, -CO-, -CO-C6H4-, -SO2NR4-, -SO2NR4-C6H4-, -SO2-, and -SO2-C6H4-. Such -C6H4-, -CONR4-, -CONR4-C6H4-, -CO-, -CO-C6H4-, -SO2NR4-, -SO2NR4-C6H4-, -SO2-, or -SO2-C6H4- is preferably contained in a molecular backbone of the PFPE-containing silane compound (A). [0046] In the formulae, α1 is an integer of 1 to 9, and may be varied depending on the valence of X1. In formula (A), α1 corresponds to a value obtained by subtracting 1 from the valence of X1. In the case where X1 is a single bond, α1 is 1. [0047] X1 is preferably a di- to heptavalent, more preferably di- to tetravalent, further preferably divalent organic group. [0048] In one embodiment, X1 is a di- to tetravalent organic group, and α1 is 1 to 3. [0049] In another embodiment, X1 is a divalent organic group, and α1 is 1. In such a case, formula (A) is represented by the following formula (A'). [0050] Examples of X1 are not limited, and include a divalent group represented by the following formula: -(R31)p'-(Xa)q'-wherein: R31 represents a single bond, -(CH2)s'-, or an o-, m-or p-phenylene group, preferably represents -(CH2)s'-, s' is an integer of 1 to 20, preferably an integer of 1 to 6, more preferably an integer of 1 to 3, still more preferably 1 or 2, Xa represents, -(Xb)l'-, each Xb, at each occurrence, independently represents a group selected from the group consisting of -O-, -S-, o-, m- or p-phenylene group, -C(O)O-, -Si(R33)2-, - (Si(R33)2O)m'-Si(R33)2-, -CONR34-, -O-CONR34-, -NR34- and-(CH2)n'-, each R33, at each occurrence, independently represents a phenyl group, a C1-6 alkyl group or a C1-6 alkoxy group, preferably represents a phenyl group or a C1-6 alkyl group, more preferably represents a methyl group, each R34, at each occurrence, independently represents a hydrogen atom, a phenyl group, or a C1-6 alkyl group (preferably a methyl group), each m', at each occurrence, is independently an integer of 1 to 100, preferably an integer of 1 to 20, each n', at each occurrence, is independently an integer of 1 to 20, preferably an integer of 1 to 6, more preferably an integer of 1 to 3, l' is an integer of 1 to 10, preferably an integer of 1 to 5, more preferably an integer of 1 to 3, p' is 0 or 1, and q' is 0 or 1, provided that at least one of p' and q' is 1, and the occurrence order of the respective repeating units in parentheses with p' or q' is not limited. Here, R31 and Xa (typically, any hydrogen atom in R31 and Xa) are each optionally substituted with one or more substituents selected from a fluorine atom, a C1-3 alkyl group and a C1-3 fluoroalkyl group. [0051] In one embodiment, l' is 1. [0052] Preferably, X1 is -(R31)p'-(Xa)q'-R32-. R32 represents a single bond, -(CH2)t'-, or an o-, m- or p-phenylene group, preferably -(CH2)t'-. Here, t' is an integer of 1 to 20, preferably an integer of 2 to 6, more preferably an integer of 2 to 3. Here, R32 (typically, any hydrogen atom in R32) is optionally substituted with one or more substituents selected from a fluorine atom, a C1-3 alkyl group and a C1-3 fluoroalkyl group. [0053] Preferably, X1 can bea single bond,a C1-20 alkylene group,-R31-Xc-R32-, or-Xd-R32-wherein R31 and R32 have the same meanings as described above. Herein, such an alkylene group is a group having a -(CδH2δ)- structure, and is optionally substituted or unsubstituted and is optionally linear or branched. [0054] More preferably, X1 isa single bond,a C1-20 alkylene group,- (CH2)s'-Xc-,- (CH2)s'-Xc-(CH2)t'--Xd-, or-Xd-(CH2)t'-wherein s' and t' have the same meanings as described above. [0055] Further preferably, X1 is-Xf-,a -Xf-C1-20 alkylene group,-Xf-(CH2)s'-Xc-,-Xf-(CH2)s'-Xc-(CH2)t'--Xf-Xd-, or-Xf-Xd-(CH2)t'- wherein s' and t' have the same meanings as described above. [0056] In the formulae, Xf is an alkylene group having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, for example, a methylene group. Any hydrogen atom in Xf is optionally substituted with one or more substituents selected from a fluorine atom, a C1-3 alkyl group and a C1-3 fluoroalkyl group, and is preferably substituted. Xf may be linear or branched, and is preferably linear. [0057] In the formulae, Xc represents-O-,-S-,-C(O)O-,-CONR34-,-O-CONR34-,-Si(R33)2-,-(Si(R33)2O)m'-Si(R33)2-,-O-(CH2)u'-(Si(R33)2O)m'-Si(R33)2-,-O-(CH2)u'-Si(R33)2-O-Si(R33)2-CH2CH2-Si(R33)2-O-Si(R33)2-,-O-(CH2)u'-Si(OCH3)2OSi(OCH3)2-,-CONR34-(CH2)u'-(Si(R33)2O)m'-Si(R33)2-,-CONR34-(CH2)u'-N(R34)-, or-CONR34-(o-, m- or p-phenylene) -Si(R33)2-wherein R33, R34 and m' have the same meanings as described above, andu' is an integer of 1 to 20, preferably an integer of 2 to 6, more preferably an integer of 2 to 3. Xc is preferably -O-. [0058] In the formulae, Xd represents-S-,-C(O)O-,-CONR34-,-CONR34-(CH2)u'-(Si(R33)2O)m'-Si(R33)2-,-CONR34-(CH2)u'-N(R34)-, or-CONR34- (o-, m- or p-phenylene) -Si (R33)2-wherein each symbol has the same meaning as described above. [0059] Particularly preferably, X1 is a group represented by-Xf-,a -Xf-C1-20 alkylene group,-Xf-(CH2)s'-Xc-,-Xf-(CH2)s'-Xc-(CH2)t'--Xf-Xd-, or-Xf-Xd-(CH2)t'-wherein Xf, s' and t' have the same meanings as described above;Xc represents -O-, or -CONR34-,Xd represents -CONR34-, andeach R34, at each occurrence, independently represents a hydrogen atom, a phenyl group, or a C1-6 alkyl group (preferably a methyl group). [0060] In one embodiment, X1 is a group represented by-Xf-(CH2)s'-Xc-,-Xf-(CH2)s'-Xc-(CH2)t'--Xf-Xd-, or-Xf-Xd-(CH2)t'-wherein Xf, s' and t' have the same meanings as described above;Xc represents -CONR34-,Xd represents -CONR34-, andeach R34, at each occurrence, independently represents a hydrogen atom, a phenyl group or a C1-6 alkyl group (preferably a methyl group). [0061] In one embodiment, X1 can be,a single bond,a C1-20 alkylene group,- (CH2)s'-Xc-(CH2)t'-, or-Xd-(CH2)t'-wherein each symbol has the same meaning as described above. [0062] Preferably, X1 isa single bond,a C1-20 alkylene group,-(CH2)s'-O-(CH2)t'-,-(CH2)s'-(Si(R33)2O)m'-Si(R33)2-(CH2)t'-,-(CH2)s'-O-(CH2)u'-(Si(R33)2O)m'-Si(R33)2-(CH2)t'-, or-(CH2)s'-O-(CH2)t'-Si(R33)2-(CH2)u'-Si(R33)2-(CvH2v)-wherein R33, m', s', t' and u' have the same meanings as described above, and v is an integer of 1 to 20, preferably an integer of 2 to 6, more preferably an integer of 2 to 3. [0063] In the formulae, -(CvH2v)- is optionally linear or branched, and can be, for example, -CH2-, -CH2CH2-,-CH2CH2CH2-, -CH(CH3)- or -CH(CH3)CH2-. [0064] The X1 group is optionally substituted with one or more substituents selected from a fluorine atom, a C1-3 alkyl group and a C1-3 fluoroalkyl group (preferably C1-3perfluoroalkyl group). [0065] In one embodiment, the X1 group can be other than a -O-C1-6 alkylene group. [0066] In another embodiment, examples of the X1 group include the following groups: [0067] Specific examples of X1 include:a single bond,-CH2OCH2-,-CH2O(CH2)2-,-CH2O(CH2)3-,-CH2O(CH2)6-,-CF2-CH2-O-CH2-,-CF2-CH2-O-(CH2)2-,-CF2-CH2-O-(CH2)3-,-CF2-CH2-O-(CH2)6-,-CH2O(CH2)3Si(CH3)2OSi(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2OSi(CH3)2OSi(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)2Si(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)3Si(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)10Si(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)2OSi(CH3)2(CH2)2-,-CH2OCF2CHFOCF2-,-CH2OCF2CHFOCF2CF2-,-CH2OCF2CHFOCF2CF2CF2-,-CH2OCH2CF2CF2OCF2-,-CH2OCH2CF2CF2OCF2CF2-,-CH2OCH2CF2CF2OCF2CF2CF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2CF2-,-CH2OCH2CHFCF2OCF2-,-CH2OCH2CHFCF2OCF2CF2-,-CH2OCH2CHFCF2OCF2CF2CF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2CF2--,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2CF2CF2-,-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CH2OCH2(CH2)7CH2Si(OCH3)2OSi(OCH3)2(CH2)2Si(OCH3)2OSi(OCH3)2(C H2)2-,-CH2OCH2CH2CH2Si(OCH3)2OSi(OCH3)2(CH2)3-,-CH2OCH2CH2CH2Si(OCH2CH3)2OSi(OCH2CH3)2(CH2)3-,-CH2OCH2CH2CH2Si(OCH3)2OSi(OCH3)2(CH2)2-,-CH2OCH2CH2CH2Si(OCH2CH3)2OSi(OCH2CH3)2(CH2)2-,- (CH2)2-Si(CH3)2-(CH2)2-,-CH2-,- (CH2)2-,- (CH2)3-,- (CH2)4-,- (CH2)5-,- (CH2)6-,-CF2-,-(CF2)2-,-CF2-CH2-,-CF2-(CH2)2-,-CF2-(CH2)3-,-CF2-(CH2)4-,-CF2-(CH2)5-,-CF2-(CH2)6-,-CO-,-CONH-,-CONH-CH2-,-CONH-(CH2)2-,-CONH-(CH2)3-,-CONH-(CH2)6-,-CF2CONH-,-CF2CONHCH2-,-CF2CONH(CH2)2-,-CF2CONH(CH2)3-,-CF2CONH(CH2)6-,-CON(CH3)-(CH2)3-,-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CON(CH3)-(CH2)6-,-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)3-,-CF2-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)6-,-CF2-CON(Ph)-(CH2) wherein Ph means phenyl,-CONH-(CH2)2NH(CH2)3-,-CONH-(CH2)6NH(CH2)3-,-CH2O-CONH-(CH2)3-,-CH2O-CONH-(CH2)6-,-S-(CH2)3-,- (CH2)2S(CH2)3-,-CONH-(CH2)3Si(CH3)2OSi(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2OSi(CH3)2OSi(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)2Si(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)3Si(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)10Si(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)2OSi(CH3)2(CH2)2-,-C(O)O-(CH2)3-,-C(O)O-(CH2)6-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-(CH2)2-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-CH(CH3)-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-(CH2)3-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-CH(CH3)-CH2-,-OCH2-,-O(CH2)3-, and-OCFHCF2- [0068] In particular, X1 is preferably-CH2OCH2-,-CH2O(CH2)2-,-CH2O(CH2)3-,-CH2O(CH2)6-,-CF2-CH2-O-CH2-,-CF2-CH2-O-(CH2)2-,-CF2-CH2-O-(CH2)3-,-CF2-CH2-O-(CH2)6-,-CH2OCF2CHFOCF2-,-CH2OCF2CHFOCF2CF2-,-CH2OCF2CHFOCF2CF2CF2-,-CH2OCH2CF2CF2OCF2-,-CH2OCH2CF2CF2OCF2CF2-,-CH2OCH2CF2CF2OCF2CF2CF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2CF2-,-CH2OCH2CHFCF2OCF2-,-CH2OCH2CHFCF2OCF2CF2-,-CH2OCH2CHFCF2OCF2CF2CF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2CF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2CF2CF2-,-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CH2-,- (CH2)2-,- (CH2)3-,- (CH2)4-,- (CH2)5-,- (CH2)6-,-CF2-,- (CF2)2-,-CF2-CH2-,-CF2-(CH2)2-,-CF2-(CH2)3-,-CF2-(CH2)4-,-CF2-(CH2)5-,-CF2-(CH2)6-,-CONH-,-CONH-CH2-,-CONH-(CH2)2-,-CONH-(CH2)3-,-CONH-(CH2)6-,-CF2CONH -,-CF2CONHCH2-,-CF2CONH(CH2)2-,-CF2CONH(CH2)3-,-CF2CONH(CH2)6-,-CON(CH3)-(CH2)3-,-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CON(CH3)-(CH2)6-,-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)3-,-CF2-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)6-,-CF2-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CONH-(CH2)2NH(CH2)3-,-CONH-(CH2)6NH(CH2)3-,-CH2O-CONH-(CH2)3-,-CH2O-CONH-(CH2)6-,-OCH2-,-O(CH2)3-, or-OCFHCF2-. [0069] In particular, X1 is more preferably-CH2OCF2CHFOCF2CF2CF2-C (O) NH-CH2-,-CONH-,-CONH-CH2-,-CONH-(CH2)2-,-CONH-(CH2)3-,-CONH-(CH2)6-,-CF2CONH-,-CF2CONHCH2-,-CF2CONH(CH2)2-,-CF2CONH(CH2)3-,-CF2CONH(CH2)6-,-CON(CH3)-(CH2)3-,-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CON(CH3)-(CH2)6-,-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)3-,-CF2-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)6-,-CF2-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CONH-(CH2)2NH(CH2)3-,-CONH-(CH2)6NH(CH2)3-. [0070] In one embodiment, X1 represents Xe'. Xe' is a single bond, an alkylene group having 1 to 6 carbon atoms, -R51-C6H4-R52-, -R51-CONR4-R52-, -R51-CONR4-C6H4-R52-, -R51-CO-R52-, -R51-CO-C6H4-R52-, -R51-SO2NR4-R52-, -R51-SO2NR4-C6H4-R52-,-R51-SO2-R52-, or -R51-SO2-C6H4-R52-. R51 and R52 each independently represent a single bond or an alkylene group having 1 to 6 carbon atoms, preferably a single bond or an alkylene group having 1 to 3 carbon atoms. R4 has the same meaning as described above. The alkylene group is substituted or unsubstituted, preferably unsubstituted. Examples of the substituent of the alkylene group can include a halogen atom, preferably a fluorine atom. The alkylene group is linear or branched, preferably linear. [0071] In a preferable embodiment, Xe' can bea single bond,-Xf-,an alkylene group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms,a -Xf-C1-6 alkylene group, preferably a -Xf-C1-3 alkylene group, more preferablya -Xf-C1-2 alkylene group,-C6H4-R52'-,-CONR4'-R52'-,-CONR4'-C6H4-R52'-,-Xf-CONR4'-R52'-,-Xf-CONR4'-C6H4-R52'--CO-R52'-,-CO-C6H4-R52'-,-SO2NR4'-R52'-,-SO2NR4'-C6H4-R52'-,-SO2-R52'-,-SO2-C6H4-R52'-,-R51'-C6H4-,-R51'-CONR4'-,-R51'-CONR4'-C6H4-,-R51'-CO-,-R51'-CO-C6H4-,-R51'-SO2NR4'-,-R51'-SO2NR4'-C6H4-,-R51'-SO2-,-R51'-SO2-C6H4-,-C6H4-,-CONR4'-,-CONR4'-C6H4-,-Xf-CONR4'-,-Xf-CONR4'-C6H4-,-CO-,-CO-C6H4-,-SO2NR4'-,-SO2NR4'-C6H4--SO2-, or-SO2-C6H4-wherein R51' and R52' each independently represent a linear alkylene group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. The alkylene group is substituted or unsubstituted, as described above, and examples of the substituent of the alkylene group can include a halogen atom, preferably a fluorine atom, andR4' is a hydrogen atom or a methyl group. [0072] In particular, Xe' can be preferably-Xf-,an alkylene group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, ora -Xf-C1-6 alkylene group, preferably a -Xf-C1-3 alkylene group, more preferablya -Xf-C1-2 alkylene group,-CONR4'-R52'-,-CONR4'-C6H4-R52'-,-Xf-CONR4'-R52'-,-Xf-CONR4'-C6H4-R52'-,-R51'-CONR4'-,-R51'-CONR4'-C6H4-,-CONR4'-,-CONR4'-C6H4-,-Xf-CONR4'-,-Xf-CONR4'-C6H4- ,-R51'-CONR4'-, or-R51'-CONR4'-C6H4-. In the formulae, Xf, R4', R51' and R52' each have the same meanings as described above. [0073] In particular, Xe' can be more preferably-CONR4'-R52'-,-CONR4'-C6H4-R52'-,-Xf-CONR4'-R52'-,-Xf-CONR4'-C6H4-R52'-,-R51'-CONR4'-,-R51'-CONR4'-C6H4-,-CONR4'-,-CONR4'-C6H4-,-Xf-CONR4'-, or-Xf-CONR4'-C6H4-. [0074] In the present embodiment, specific examples of Xe' includea single bond,a perfluoroalkylene group having 1 to 6 carbon atoms (for example, -CF2-, -(CF2)2-),an alkylene group having 1 to 6 carbon atoms,-CF2-C1-6 alkylene group,-CONH-,-CONH-CH2-,-CONH-(CH2)2-,-CONH-(CH2)3-,-CF2-CONH-,-CF2CONHCH2-,-CF2CONH(CH2)2-,-CF2CONH(CH2)3-,-CON(CH3)-,-CON(CH3)-CH2-,-CON(CH3)-(CH2)2-,-CON(CH3)-(CH2)3-,-CF2-CON(CH3)-,-CF2-CON(CH3)CH2-,-CF2-CON(CH3)-(CH2)2-,-CF2-CON(CH3)-(CH2)3-,-CH2-CONH-,-CH2-CONH-CH2-,-CH2-CONH-(CH2)2-,-CH2-CONH-(CH2)3-,-CF2-CH2-CONH-,-CF2-CH2-CONH-CH2-,-CF2-CH2-CONH-(CH2)2-,-CF2-CH2-CONH-(CH2)3-,-CONH-C6H4-,-CON(CH3)-C6H4-,-CH2-CON(CH3)-CH2-,-CH2-CON(CH3)-(CH2)2-,-CH2-CON(CH3)-(CH2)3-,-CON(CH3)-C6H4-,-CF2-CONH-C6H4-,-CF2-CON(CH3)-C6H4-,-CF2-CH2-CON(CH3)-CH2-,-CF2-CH2-CON(CH3)-(CH2)2-,-CF2-CH2-CON(CH3)-(CH2)3-,-CF2-CON(CH3)-C6H4-,-CO-,-CO-C6H4-,-C6H4-,-SO2NH-,-SO2NH-CH2-,-SO2NH-(CH2)2-,-SO2NH-(CH2)3-,-SO2NH-C6H4-,-SO2N(CH3)-,-SO2N(CH3)-CH2-,-SO2N(CH3)-(CH2)2-,-SO2N(CH3)-(CH2)3-,-SO2N(CH3)-C6H4-,-SO2-,-SO2-CH2-,-SO2-(CH2)2-,-SO2-(CH2)3-, or-SO2-C6H4-. [0075] In the above list, examples of preferable Xe' include an alkylene group having 1 to 6 carbon atoms,a perfluoroalkylene group having 1 to 6 carbon atoms (for example, -CF2- and -(CF2)2-),a -CF2-C1-6 alkylene group,-CONH-,-CONH-CH2-,-CONH-(CH2)2-,-CONH-(CH2)3-,-CF2CONH-,-CF2CONHCH2-,-CF2CONH(CH2)2-,-CF2CONH(CH2)3-,-CON(CH3)-,-CON(CH3)-CH2-,-CON(CH3)-(CH2)2-,-CON(CH3)-(CH2)3-,-CF2-CON(CH3)-,-CF2-CON(CH3)CH2-,-CF2-CON(CH3)-(CH2)2-,-CF2-CON(CH3)-(CH2)3-,-CH2-CONH-,-CH2-CONH-CH2-,-CH2-CONH-(CH2)2-,-CH2-CONH-(CH2)3-,-CF2-CH2-CONH-,-CF2-CH2-CONH-CH2-,-CF2-CH2-CONH-(CH2)2-,-CF2-CH2-CONH-(CH2)3-,-CONH-C6H4-,-CON(CH3)-C6H4-,-CH2-CON(CH3)-CH2-,-CH2-CON(CH3)-(CH2)2-,-CH2-CON(CH3)-(CH2)3-,-CON(CH3)-C6H4--CF2-CONH-C6H4-,-CF2-CON(CH3) -C6H4-,-CF2-CH2-CON(CH3)-CH2-,-CF2-CH2-CON(CH3)-(CH2)2-,-CF2-CH2-CON(CH3)-(CH2)3-, and-CF2-CON(CH3)-C6H4. [0076] In the above list, examples of more preferable Xe' include-CONH-,-CONH-CH2-,-CONH-(CH2)2-,-CONH-(CH2)3-,-CF2CONH-,-CF2CONHCH2-,-CF2CONH(CH2)2-,-CF2CONH(CH2)3-,-CON(CH3)-,-CON(CH3)-CH2-,-CON(CH3)-(CH2)2-,-CON(CH3)-(CH2)3-,-CF2-CON(CH3)-,-CF2-CON(CH3)CH2-,-CF2-CON(CH3)-(CH2)2-,-CF2-CON(CH3)-(CH2)3-,-CH2-CONH-,-CH2-CONH-CH2-,-CH2-CONH-(CH2)2-,-CH2-CONH-(CH2)3-,-CF2-CH2-CONH-,-CF2-CH2-CONH-CH2-,-CF2-CH2-CONH-(CH2)2-,-CF2-CH2-CONH-(CH2)3-,-CONH-C6H4-,-CON(CH3)-C6H4-,-CH2-CON(CH3)-CH2-,-CH2-CON(CH3)-(CH2)2-,-CH2-CON(CH3)-(CH2)3-,-CON(CH3)-C6H4--CF2-CONH-C6H4-,-CF2-CON(CH3)-C6H4-,-CF2-CH2-CON(CH3)-CH2-,-CF2-CH2-CON(CH3)-(CH2)2-,-CF2-CH2-CON(CH3)-(CH2)3-, or-CF2-CON(CH3)-C6H4-. [0077] In one embodiment, Xe' is a single bond. In the present embodiment, PFPE and a group having a binding ability to the base material (namely, group in parentheses with α1 in (A)) are directly bonded. [0078] In still another embodiment, X1 is a group represented by formula: -(R16)x-(CFR17)y-(CH2)z-, In the formula, x, y and z are each independently an integer of 0 to 10, the sum of x, y and z is 1 or more, and the occurrence order of the respective repeating units in parentheses is not limited in the formula. [0079] In the formula, each R16, at each occurrence, independently represents an oxygen atom, phenylene, carbazolylene, -NR18-, wherein R18 represents a hydrogen atom or an organic group, or a divalent organic group. Preferably, R16 is an oxygen atom or a divalent polar group. [0080] The "divalent polar group" is not limited, and examples thereof include -C(O)-, -C(=NR19)-, and-C(O)NR19-, wherein R19 represents a hydrogen atom or a lower alkyl group. The "lower alkyl group" is, for example, an alkyl group having 1 to 6 carbon atoms, such as a methyl group, an ethyl group, or a n-propyl group, and such a group is optionally substituted with one or more fluorine atoms. [0081] In the formula, each R17, at each occurrence, is independently a hydrogen atom, a fluorine atom or a lower fluoroalkyl group, preferably a fluorine atom. The "lower fluoroalkyl group" is, for example, a fluoroalkyl group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, preferably a perfluoroalkyl group having 1 to 3 carbon atoms, more preferably a trifluoromethyl group or a pentafluoroethyl group, further preferably a trifluoromethyl group. [0082] In this embodiment, X1 is preferably a group represented by formula: -(O)x-(CF2)y-(CH2)z-, wherein x, y and z have the same meanings as described above, and the occurrence order of the respective repeating units in parentheses is not limited in the formula. [0083] Examples of the group represented by formula: -(O)x-(CF2)y-(CH2)z- include any group represented by -(O)x'-(CH2)z"-O-[(CH2)z'''O-]z"", and -(O)x'-(CF2)y"-(CH2)z"-O-[(CH2)z'''-O-]z"", wherein x' is 0 or 1, y", z" and z''' are each independently an integer of 1 to 10, and z"" is 0 or 1. Herein, a left end of such a group is bonding to PFPE. [0084] In another preferable embodiment, X1 is -O-CFR20-(CF2)e'-. [0085] Each R20 independently represents a fluorine atom or a lower fluoroalkyl group. The lower fluoroalkyl group is, for example, a fluoroalkyl group having 1 to 3 carbon atoms, preferably a perfluoroalkyl group having 1 to 3 carbon atoms, more preferably a trifluoromethyl group or a pentafluoroethyl group, further preferably a trifluoromethyl group. [0086] Each e' is independently 0 or 1. [0087] In one specific example, R20 is a fluorine atom and e' is 1. [0088] In still another embodiment, examples of the X1 group include the following groups: [0089] The radical scavenging group is not limited as long as it can scavenge a radial generated by light irradiation, and examples thereof include a residue of benzophenones, benzotriazoles, benzoates, phenyl salicylates, crotonic acids, malonates, organoacrylates, hindered amines, hindered phenols, or triazines. [0090] The UV absorbing group is not limited as long as it can absorb ultraviolet light, and examples thereof include a residue of benzotriazoles, hydroxybenzophenones, esters of substituted and unsubstituted benzoic acid or salicylic acid compounds, acrylates or alkoxy cinnamates, oxamides, oxanilides, benzoxazinones, and benzoxazoles. [0091] In a preferable embodiment, examples of a preferable radical scavenging group or an UV absorbing group include [0092] In this embodiment, X1 (and, the following X3, X5 and X7) can be a tri- to decavalent organic group. [0093] In the formulae, each X2, at each occurrence, independently represents a single bond or a divalent organic group. X2 is preferably an alkylene group having 1 to 20 carbon atoms, more preferably -(CH2)u-, wherein u is an integer of 0 to 2. [0094] In the formulae, each t is independently an integer of 1 to 10. In a preferable embodiment, t is an integer of 1 to 6. In another preferable embodiment, t is an integer of 2 to 10, preferably an integer of 2 to 6. [0095] A preferable compound represented by formula (A) is a compound represented by the following formula (A'): [0096] Such any compound represented by formula (A) can be obtained by, for example, introducing iodine into an end of a perfluoropolyether derivative corresponding to a-PFPE- moiety, as a raw material, and reacting a vinyl monomer corresponding to -CH2CR12(X2-SiR13 n1R14 3-n1)-.Formula (B): (R14 3-n1R13 n1Si)β1-X3-PFPE-X3-(SiR13" n1R14" 3-n1)β1 ... (B) [0097] In formula (B), PFPE, R13, R13", R14, R14" and n1 have the same meanings as described with respect to the formula (A). [0098] In formula (B), such a Si atom bonding to at least one group selected from the group consisting of a hydroxyl group and a hydrolyzable group indicates a Si atom contained in (-SiR13 n1R14 3-n1) or (-SiR13" n1R14" 3-n1) where n1 is an integer of 1 to 3. [0099] In the formulae, n1 with respect to each (-SiR13 n1R14 3-n1) unit or each (-SiR13" n1R14" 3-n1) unit is independently an integer of 0 to 3, preferably 1 to 3, more preferably 3. In the formulae, at least two n1(s) are each an integer of 1 to 3, namely, there is not any case where all n1(s) are simultaneously 0. That is, at least two of R13 and R13" are present in the formulae. That is, at least two structures selected from the group consisting of a-SiR13 n1R14 3-n1 structure (namely, -SiR13 moiety) where n1 is 1 or more and a -SiR13" n1R14" 3-n1 structure (namely, -SiR13" moiety) where n1 is 1 or more are present in formula (B). [0100] More preferably, at least one Si bonding to the hydroxyl group or the hydrolyzable group is present at each of both ends of a molecular backbone of the PFPE-containing silane compound (A), in formula (B). That is, at least one -SiR13 moiety is present, and at least one-SiR13" moiety is present. [0101] In the formulae, each X3 independently represents a single bond or a di- to decavalent organic group. X3 is understood to be a linker which links a perfluoropolyether moiety (namely, -PFPE- moiety) mainly providing water-repellency, surface lubricity, and the like, and a silane moiety (specifically, -SiR13 n1R14 3-n1 or -SiR13" n1R14" 3-n1) providing a binding ability to the base material, in any compound represented by formula (B). Accordingly, X3 may be a single bond or any organic group as long as such any compound represented by formula (B) can be stably present. Herein, a left portion and a right portion of the structure designated as X3 are bonding to the group represented by PFPE and the group in parentheses with β1, respectively. [0102] In another embodiment, X3 represents Xe. Xe has the same meaning as described above. [0103] In the formulae, β1 is an integer of 1 to 9, and may be varied depending on the valence of X3. In formula (B), β1 corresponds to a value obtained by subtracting 1 from the value of the valence of X3. In the case where X3 is a single bond, β1 is 1. [0104] X3 is preferably a di- to heptavalent, more preferably di- to tetravalent, further preferably divalent organic group. [0105] In one embodiment, X3 is a di- to tetravalent organic group, and β1 is 1 to 3. [0106] In another embodiment, X3 is a divalent organic group, and β1 is 1. In such a case, formula (B) is represented by the following formula (B'). R14 3-n1R13 n1Si-X3-PFPE-X3-SiR13" n1R14" 3-n1 ... (B') [0107] Examples of X3 are not limited, and include the same as described with respect to X1. [0108] In particular, preferable specific examples of X3 includea single bond,-CH2OCH2-,-CH2O(CH2)2-,-CH2O(CH2)3-,-CH2O(CH2)6-,-CF2-CH2-O-CH2-,-CF2-CH2-O-(CH2)2-,-CF2-CH2-O-(CH2)3-,-CF2-CH2-O-(CH2)6-,-CH2O(CH2)3Si(CH3)2OSi(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2OSi(CH3)2OSi(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)2Si(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)3Si(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)10Si(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)2OSi(CH3)2(CH2)2-,-CH2OCF2CHFOCF2-,-CH2OCF2CHFOCF2CF2-,-CH2OCF2CHFOCF2CF2CF2-,-CH2OCH2CF2CF2OCF2-,-CH2OCH2CF2CF2OCF2CF2-,-CH2OCH2CF2CF2OCF2CF2CF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2CF2-,-CH2OCH2CHFCF2OCF2-,-CH2OCH2CHFCF2OCF2CF2-,-CH2OCH2CHFCF2OCF2CF2CF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2-,-CH2OCH2CHFCF2O=OCF(CF3)CF2OCF2CF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2CF2CF2-,-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CH2OCH2(CH2)7CH2Si(OCH3)2OSi(OCH3)2(CH2)2Si(OCH3)2OSi(OCH3)2(C H2)2-,-CH2OCH2CH2CH2Si(OCH3)2OSi(OCH3)2(CH2)3-,-CH2OCHzCH2CH2Si(OCH2CH3)2OSi(OCH2CH3)2(CH2)3-,-CH2OCH2CH2CH2Si(OCH3)2OSi(OCH3)2(CH2)2-,-CH2OCH2CH2CH2Si(OCH2CH3)2OSi(OCH2CH3)2(CH2)2-,-(CH2)2-Si(CH3)2-(CH2)2-,-CH2-,-(CH2)2-,-(CH2)3-,-(CH2)4-,-(CH2)5-,-(CH2)6-,-CF2-,-(CF2)2-,-CF2-CH2-,-CF2-(CH2)2-,-CF2-(CH2)3-,-CF2-(CH2)4-,-CF2-(CH2)5-,-CF2-(CH2)6-,-CO-,-CONH-,-CONH-CH2-,-CONH-(CH2)2-,-CONH-(CH2)3-,-CONH-(CH2)6-,-CF2CONH-,-CF2CONHCH2-,-CF2CONH(CH2)2-,-CF2CONH(CH2)3-,-CF2CONH(CH2)6-,-CON(CH3)-(CH2)3-,-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CON(CH3)-(CH2)6-,-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)3-,-CF2-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)6-,-CF2-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CONH-(CH2)2NH(CH2)3-,-CONH-(CH2)6NH(CH2)3-,-CH2O-CONH-(CH2)3-,-CH2O-CONH-(CH2)6-,-S-(CH2)3-,-(CH2)2S(CH2)3-,-CONH-(CH2)3Si(CH3)2OSi(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2OSi(CH3)2OSi(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)2Si(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)3Si(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)10Si(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)2OSi(CH3)2(CH2)2-,-C(O)O-(CH2)3-,-C(O)O-(CH2)6-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-(CH2)2-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-CH(CH3)-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-(CH2)3-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-CH(CH3)-CH2-,-OCH2-,-O(CH2)3-, and-OCFHCF2- [0109] In particular, X3 is preferably-CH2OCH2- ,-CH2O(CH2)2-,-CH2O(CH2)3-,-CH2O(CH2)6-,-CF2-CH2-O-CH2- ,-CF2-CH2-O-(CH2)2-,-CF2-CH2-O-(CH2)3-,-CF2-CH2-O-(CH2)6-,-CH2OCF2CHFOCF2- ,-CH2OCF2CHFOCF2CF2- ,-CH2OCF2CHFOCF2CF2CF2-,-CH2OCH2CF2CF2OCF2- ,-CH2OCH2CF2CF2OCF2CF2-,-CH2OCH2CF2CF2OCF2CF2CF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2CF2-,-CH2OCH2CHFCF2OCF2-,-CH2OCH2CHFCF2OCF2CF2-,-CH2OCH2CHFCF2OCF2CF2CF2- ,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2CF2-,-CHzOCHzCHFCF2OCF(CF3)CF2OCF2CF2CF2-,-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CF2-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CH2-,-(CH2)2-,-(CH2)3-,-(CH2)4-,-(CH2)5-,-(CH2)6-,-CF2-,-(CF2)2-,-CF2-CH2-,-CF2-(CH2)2-,-CF2-(CH2)3-,-CF2-(CH2)4-,-CF2-(CH2)5-,-CF2-(CH2)6-,-CONH-,-CONH-CH2- ,-CONH-(CH2)2-,-CONH-(CH2)3-,-CONH-(CH2)6-,-CF2CONH- ,-CF2CONHCH2- ,-CF2CONH(CH2)2-,-CF2CONH(CH2)3-,-CF2CONH(CH2)6-,-CON(CH3)-(CH2)3-,-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CON(CH3)-(CH2)6-,-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)3-,-CF2-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)6-,-CF2-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CONH-(CH2)2NH(CH2)3-,-CONH-(CH2)6NH(CH2)3-,-CH2O-CONH-(CH2)3-,-CH2O-CONH-(CH2)6-,-OCH2-,-O(CH2)3-,-OCFHCF2- . [0110] In particular, X3 is more preferably-CH2OCF2CHFOCF2CF2CF2-C (O) NH-CH2-,-CF2-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CONH-,-CONH-CH2- ,-CONH- (CH2)2-,-CONH- (CH2)3-,-CONH- (CH2)6-,-CF2CONH- ,-CF2CONHCH2- ,-CF2CONH(CH2)2-,-CF2CONH(CH2)3-,-CF2CONH(CH2)6-,-CON(CH3)-(CH2)3-,-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CON(CH3)-(CH2)6-,-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)3-,-CF2-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)6-,-CF2-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CONH-(CH2)2NH(CH2)3-,-CONH-(CH2)6NH(CH2)3- . [0111] In another preferable embodiment, X3 represents Xe'. Xe' has the same meaning as described above. [0112] In one embodiment, Xe' is a single bond. In the present embodiment, PFPE and a group having a binding ability to the base material (namely, group in parentheses with β1 in (B)) are directly bonded. [0113] In one embodiment, at least two Si each bonding to the hydroxyl group or the hydrolyzable group are present in formula (B). That is, at least two SiR13 moieties are present in formula (B). [0114] A preferable compound represented by formula (B) is a compound represented by the following formula (B'): R14 3-n1R13 n1Si-X3-PFPE-X3-SiR13" n1R14" 3-n1 ··· (B')wherein: each PFPE, at each occurrence, is independently a group represented by formula: -(OC6F12)a-(OC5F10)b-(OC4F8)c-(OC3F6)d-(OC2F4)e-(OCF2)f-wherein a, b, c, d, e and f are each independently an integer of 0 or more and 200 or less, the sum of a, b, c, d, e and f is at least 1, and the occurrence order of the respective repeating units in parentheses with a, b, c, d, e or f is not limited in the formula; each R13, at each occurrence, independently represents a hydroxyl group or a hydrolyzable group; each R14, at each occurrence, independently represents a hydrogen atom or an alkyl group having 1 to 22 carbon atoms; R13", R14" have the same meanings as R13, R14, respectively; n1 is an integer of 1 to 3, preferably 3; and X3 is -CH2O(CH2)2-, -CH2O(CH2)3- or -CH2O(CH2)6-. [0115] Such any compound represented by formula (B) can be produced by a known method, for example, a method described in JP 2013-117012 A , or an improved method thereof.Formula (C): (Rc m1Rb l1Ra k1Si)γ1-X5-PFPE- X5-(SiRa" k1Rb" l1Rc" m1)γ1 ··· (C) [0116] In formula (C), PFPE has the same meaning as described above. [0117] In the formula, each X5 independently represents a single bond or a di- to decavalent organic group. X5 is understood to be a linker which links a perfluoropolyether moiety (namely, -PFPE- moiety) mainly providing water-repellency, surface lubricity, and the like, and a silane moiety (specifically, -SiRa k1Rb l1Rc m1 group or -SiRa" k1Rb" l1Rc" m1 group) providing a binding ability to the base material, in any compound represented by formula (C). Accordingly, X5 may be a single bond or any organic group as long as such any compound represented by formula (C) can be stably present. Herein, a left portion and a right portion of the structure designated as X5 are bonding to the group represented by PFPE and the group in parentheses with γ1, respectively. [0118] In another embodiment, X5 represents Xe. Xe has the same meaning as described above. [0119] In the formula, γ1 is an integer of 1 to 9, and γ1 may be varied depending on the valence of X5. In formula (C), γ1 corresponds to a value obtained by subtracting 1 from the value of the valence of X5. In the case where X5 is a single bond, γ1 is 1. [0120] X5 is preferably a di- to heptavalent, more preferably di- to tetravalent, further preferably divalent organic group. [0121] In one embodiment, X5 is a di- to tetravalent organic group, and γ1 is 1 to 3. [0122] In another embodiment, X5 is a divalent organic group, and γ1 is 1. In such a case, formula (C) is represented by the following formula (C'). Rc m1Rb l1Ra k1Si-X5-PFPE-X5-SiRa" k1Rb" l1Rc" m1 ··· (C') [0123] Examples of X5 are not limited, and include the same as described with respect to X1. [0124] In particular, preferable specific examples of X5 includea single bond,-CH2OCH2-,-CH2O(CH2)2-,-CH2O(CH2)3-,-CH2O(CH2)6-,-CF2-CH2-O-CH2-,-CF2-CH2-O-(CH2)2-,-CF2-CH2-O-(CH2)3-,-CF2-CH2-O-(CH2)6-,-CH2O(CH2)3Si(CH3)2OSi(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2OSi(CH3)2OSi(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)2Si(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)3Si(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)10Si(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)2OSi(CH3)2(CH2)2-,-CH2OCF2CHFOCF2- ,-CH2OCF2CHFOCF2CF2- ,-CH2OCF2CHFOCF2CF2CF2- ,-CH2OCH2CF2CF2OCF2- ,-CH2OCH2CF2CF2OCF2CF2- ,-CH2OCH2CF2CF2OCF2CF2CF2- ,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2CF2-,-CH2OCH2CHFCF2OCF2- ,-CH2OCH2CHFCF2OCF2CF2-,-CH2OCH2CHFCF2OCF2CF2CF2- ,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2CF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2CF2CF2-,-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CH2OCH2(CH2)7CH2Si(OCH3)2OSi(OCH3)2(CH2)2Si(OCH3)2OSi(OCH3)2(C H2)2-,-CH2OCH2CH2CH2Si(OCH3)2OSi(OCH3)2(CH2)3-,-CH2OCH2CH2CH2Si(OCH2CH3)2OSi(OCH2CH3)2(CH2)3-,-CH2OCH2CH2CH2Si(OCH3)2OSi(OCH3)2(CH2)2-,-CH2OCH2CH2CH2Si(OCH2CH3)2OSi(OCH2CH3)2(CH2)2-,-(CH2)2-Si(CH3)2-(CH2)2-,-CH2-,-(CH2)2-,-(CH2)3-,-(CH2)4-,-(CH2)5-,-(CH2)6-,-CF2- ,-(CF2)2-,-CF2-CH2- ,-CF2-(CH2)2-,-CF2-(CH2)3-,-CF2-(CH2)4-,-CF2-(CH2)5-,-CF2-(CH2)6-,-CO-,-CONH-,-CONH-CH2- ,-CONH-(CH2)2-,-CONH-(CH2)3-,-CONH-(CH2)6-,-CF2CONH-,-CF2CONHCH2- ,-CF2CONH(CH2)2-,-CF2CONH(CH2)3-,-CF2CONH(CH2)6-,-CON(CH3)-(CH2)3-,-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CON(CH3)-(CH2)6-,-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)3-,-CF2-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)6-,-CF2-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CONH-(CH2)2NH(CH2)3-,-CONH-(CH2)6NH(CH2)3-,-CH2O-CONH-(CH2)3-,-CH2O-CONH-(CH2)6-,-S-(CH2)3-,-(CH2)2S(CH2)3-,-CONH-(CH2)3Si(CH3)2OSi(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2OSi(CH3)2OSi(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)2Si(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)3Si(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)10Si(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)2OSi(CH3)2(CH2)2-,-C(O)O-(CH2)3-,-C(O)O-(CH2)6-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-(CH2)2-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-CH(CH3)-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-(CH2)3-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-CH(CH3)-CH2-,-OCH2-,-O(CH2)3-, and-OCFHCF2- [0125] In particular, X5 is preferably-CH2OCH2- ,-CH2O(CH2)2-,-CH2O(CH2)3-,-CH2O(CH2)6-,-CF2-CH2-O-CH2-,-CF2-CH2-O-(CH2)2-,-CF2-CH2-O-(CH2)3-,-CF2-CH2-O-(CH2)6-,-CH2OCF2CHFOCF2- ,-CH2OCF2CHFOCF2CF2- ,-CH2OCF2CHFOCF2CF2CF2-, -CH2OCH2CF2CF2OCF2- ,-CH2OCH2CF2CF2OCF2CF2-,-CH2OCH2CF2CF2OCF2CF2CF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2CF2-,-CHZOCH2CHFCF2OCF2- ,-CH2OCH2CHFCF2OCF2CF2- ,-CH2OCH2CHFCF2OCF2CF2CF2- ,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2CF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2CF2CF2-,-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CF2-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CH2-,-(CH2)2-,-(CH2)3-,-(CH2)4-,-(CH2)5-,-(CH2)6-,-CF2-,-(CF2)2-,-CF2-CH2-,-CF2-(CH2)2-,-CF2-(CH2)3-,-CF2-(CH2)4-,-CF2-(CH2)5-,-CF2-(CH2)6-,-CONH-,-CONH-CH2-,-CONH-(CH2)2-,-CONH-(CH2)3-,-CONH-(CH2)6-,-CF2CONH- ,-CF2CONHCH2-,-CF2CONH(CH2)2-,-CF2CONH(CH2)3-,-CF2CONH(CH2)6-,-CON(CH3)-(CH2)3-,-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CON(CH3)-(CH2)6-,-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)3-,-CF2-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)6-,-CF2-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CONH-(CH2)2NH(CH2)3-,-CONH-(CH2)6NH(CH2)3-,-CH2O-CONH-(CH2)3-,-CH2O-CONH-(CH2)6-,-OCH2-,-O(CH2)3-,-OCFHCF2-. [0126] In particular, X5 is more preferably-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CF2-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CONH-,-CONH-CH2-,-CONH-(CH2)2-,-CONH-(CH2)3-,-CONH-(CH2)6-,-CF2CONH- ,-CF2CONHCH2-,-CF2CONH(CH2)2-,-CF2CONH(CH2)3-,-CF2CONH(CH2)6-,-CON(CH3)-(CH2)3-,-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CON(CHH2)6-,-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)3-,-CF2-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)6-,-CF2-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CONH-(CH2)2NH(CH2)3-,-CONH-(CH2)6NH(CH2)3- . [0127] In another preferable embodiment, X5 represents Xe'. Xe' has the same meaning as described above. [0128] In one embodiment, Xe' is a single bond. In the present embodiment, PFPE and a group having a binding ability to the base material (namely, group in parentheses with γ1 in formula (C)) are directly bonded. [0129] In the formula, each Ra, at each occurrence, independently represents -Z3-SiR71 p1R72 q1R73 r1. [0130] In the formula, each Z3, at each occurrence, independently represents an oxygen atom or a divalent organic group. [0131] Z3 is preferably a divalent organic group, and does not encompass any group which is taken together with a Si atom at an end of a molecular backbone in formula (C) (Si atom to which Ra is bonded) to form a siloxane bond. [0132] Z3 is preferably a C1-6 alkylene group, -(CH2)g-O-(CH2)h-, wherein g is an integer of 1 to 6, h is an integer of 1 to 6), or -phenylene-(CH2)i-, wherein i is an integer of 0 to 6), more preferably a C1-3 alkylene group. Such a group is optionally substituted with one or more substituents selected from, for example, a fluorine atom, a C1-6 alkyl group, a C2-6 alkenyl group and a C2-6 alkynyl group. Z3 is more preferably a linear or branched alkylene group, further preferably a linear alkylene group from the viewpoint of particularly favorable ultraviolet durability. The number of carbon atoms constituting the alkylene group of Z3 is preferably in the range from 1 to 6, more preferably in the range from 1 to 3. The alkylene group is as described above. [0133] In the formulae, each R71, at each occurrence, independently represents Ra'. Ra' has the same meaning as Ra. [0134] The number of Si linearly linked via a Z3 group is at most 5 in Ra. That is, in the case where at least one R71 is present in Ra, two or more Si atoms linearly linked via a Z3 group are present in Ra, and the number of such Si atoms linearly linked via a Z3 group is at most 5. Herein, the "number of Si atoms linearly linked via a Z3 group in Ra" is equal to the number of repeatings of -Z3-Si- linearly linked in Ra. [0135] One example is represented below, where Si atoms are linked via a Z3 group in Ra. [0136] In the formula, "*" means a site bonded to Si of a main chain, and "..." means that a predetermined group other than Z3Si is bonded, namely, "..." means a position at which repeating of Z3Si is terminated in the case where all three bonds of a Si atom are "...". The superscript number in Si means the number of occurrence of Si linearly linked via a Z3 group when counted from "*". That is, a chain where repeating of Z3Si is terminated at Si2 is a chain where the "number of Si atoms linearly linked via a Z3 group in Ra" is 2, and similarly, chains where repeating of Z3Si is terminated at Si3, Si4 and Si5 mean chains where the "number of Si atoms linearly linked via a Z3 group in Ra" is 3, 4 and 5, respectively. As clear from the formula, a plurality of Z3Si chains are present in Ra, and all the chains do not necessarily have the same length, and, for example, may each have any length. [0137] In a preferable embodiment, the "number of Si atoms linearly linked via a Z3 group in Ra" is 1 (left formula) or 2 (right formula) in all chains, as represented below. [0138] In one embodiment, the number of Si atoms linearly linked via a Z3 group in Ra is 1 or 2, preferably 1. [0139] In the formulae, each R72, at each occurrence, independently represents a hydroxyl group or a hydrolyzable group. The "hydrolyzable group" has the same meaning as described above. [0140] Preferably, R72 is -OR, wherein R represents a substituted or unsubstituted C1-3 alkyl group, more preferably a methyl group. [0141] In the formulae, each R73, at each occurrence, independently represents a hydrogen atom or a lower alkyl group. The lower alkyl group is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, further preferably a methyl group. [0142] In the formulae, each p1, at each occurrence, is independently an integer of 0 to 3; each q1, at each occurrence, is independently an integer of 0 to 3; and each r1, at each occurrence, is independently an integer of 0 to 3, provided that the sum of p1, q1 and r1 with respect to (-Z3-SiR71 p1R72 q1R73 r1) is 3. [0143] In a preferable embodiment, q1 in Ra' at an end of Ra (Ra in the case where no Ra' is present) is preferably 2 or more, for example, 2 or 3, more preferably 3. [0144] In a preferable embodiment, at least one end of Ra can be -Si(-Z3-SiR72 q1R73 r1)2R72 q1'R73 r1' (provided that either one of q1' and r1' is 1 and the other is 0) or -Si(-Z3-SiR72 q1R73 r1) 3, preferably -Si(-Z3-SiR72 q1R73 r1)3 (wherein the total of q1 and r1 is 3). In the formula, a (-Z3-SiR72 q1R73 r1) unit is preferably (-Z3-SiR72 3). In a further preferable embodiment, all ends of Ra can be -Si(-Z3-SiR72 q1R73 r1) 3, preferably -Si(-Z3-SiR72 3)3. [0145] In a preferable embodiment, an end of a group represented by (SiRa k1Rb l1Rc m1) can be -Si(-Z3-SiR72 q1R73 r1)2Rb l1Rc m1 (provided that any one of l1 and m1 is 1 and the other is 0), -Si(-Z3-SiR72 q1R73 r1)2R72 q1'R73 r1' (provided that any one of q1' and r1' is 1 and the other is 0), or -Si(-Z3-SiR72 q1R73 r1)3, preferably -Si(-Z3-SiR72 q1R73 r1)3 (wherein the total of q1 and r1 is 3). More preferably, an end of a group represented by (SiRa k1Rb l1Rc m1) is -Si(-Z3-SiR72 3)3. [0146] In the formulae, each Ra", at each occurrence, independently represents -Z3-SiR71 p1R72" q1R73 r1. Z3, R71, R73, p1, q1 and r1 have the same meanings as described above. R72" has the same meaning as R72. [0147] In a preferable embodiment, at least one end of Ra" can be -Si(-Z3-SiR72" q1R73 r1)2R72" q1'R73 r1' (provided that either one of q1' and r1' is 1 and the other is 0), or - Si(-Z3-SiR72" q1R73 r1)3, preferably -Si(-Z3-SiR72" q1R73 r1)3 (wherein the total of q1 and r1 is 3). In the formula, a (-Z3-SiR72" q1R73 r1) unit is preferably (-Z3-SiR72" 3). In a further preferable embodiment, all ends of Ra can be-Si(-Z3-SiR72" q1R73 r1)3, preferably -Si(-Z3-SiR72" 3)3. [0148] In a preferable embodiment, an end of a group represented by (SiRa" k1Rb" l1Rc" m1) can be -Si(-Z3-SiR72" q1R73 r1)2Rb" l1Rc" m1 (provided that any one of l1 and m1 is 1 and the other is 0), -Si(-Z3-SiR72" q1R73 r1)2R72" q1'R73 r1' (provided that any one of q1' and r1' is 1 and the other is 0), or -Si (-Z3-SiR72" q1R73 r1)3, preferably -Si(-Z3-SiR72" q1R73 r1)3 (wherein the total of q1 and r1 is 3). More preferably, an end of a group represented by (SiRa" k1Rb" l1Rc" m1) is -Si(-Z3-SiR72" 3)3. [0149] At least two Si atoms each bonding to the hydroxyl group or the hydrolyzable group are present in formula (C). That is, at least two structures selected from the group consisting of SiR72 (specifically, a group represented by -SiR71 p1R72 q1R73 r1, provided that q1 is an integer of 1 to 3), SiR72" (specifically, a group represented by -SiR71 p1R72" q1R73 r1, provided that q1 is an integer of 1 to 3), SiRb (specifically, a group represented by -SiRa k1Rb l1Rc m1, provided that 11 is an integer of 1 to 3) and SiRb" (specifically, a group represented by -SiRa" k1Rb" l1Rc" m1, provided that 11 is an integer of 1 to 3) are present. Rb and Rb" are described below. [0150] More preferably, at least one Si bonding to the hydroxyl group or the hydrolyzable group is present at each of both ends of a molecular backbone of the PFPE-containing silane compound (A), in formula (C). That is, at least one SiR72 and/or SiRb structure is present, and at least one SiR72" and/or SiRb" structure is present. [0151] In the formulae, each Rb, at each occurrence, independently represents a hydroxyl group or a hydrolyzable group. [0152] Rb preferably represents a hydroxyl group, -OR, - OCOR, -O-N=C(R)2, -N(R)2, -NHR, or halogen, wherein R represents a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, and Rb more preferably represents -OR. Examples of R include unsubstituted alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a n-butyl group and an isobutyl group; and substituted alkyl groups such as a chloromethyl group. Among them, an alkyl group, in particular, an unsubstituted alkyl group is preferable, and a methyl group or an ethyl group is more preferable. The hydroxyl group is not limited, and, may be generated by hydrolyzing the hydrolyzable group. More preferably, Rb represents -OR, wherein R represents a substituted or unsubstituted C1-3 alkyl group, more preferably a methyl group. [0153] In the formulae, Rb" has the same meaning as Rb. [0154] In the formulae, each Rc, at each occurrence, independently represents a hydrogen atom or a lower alkyl group. The lower alkyl group is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, further preferably a methyl group. [0155] In the formulae, Rc" has the same meaning as Rc. [0156] In the formulae, each k1, at each occurrence, is independently an integer of 0 to 3; each 11, at each occurrence, is independently an integer of 0 to 3; and each m1, at each occurrence, is independently an integer of 0 to 3, provided that the sum of k1, l1 and m1 with respect to (SiRa k1Rb l1Rc m1) or with respect to (SiRa" k1Rb" l1Rc" m1) is 3. [0157] In one embodiment, k1 is preferably 1 to 3, more preferably 3. [0158] Such any compound represented by formula (C) can be synthesized as described in WO 2014/069592 .Formula (D): (Rf m2Re l2Rd k2C)δ1-X7-PFPE-X7-(CRd" k2Re" l2Rf" m2)δ1 ··· (D) [0159] In formula (D), PFPE has the same meaning as described with respect to formula (A). [0160] In the formula, each X7 independently represents a single bond or a di- to decavalent organic group. X7 is understood to be a linker which links a perfluoropolyether moiety (namely, -PFPE- moiety) mainly providing water-repellency, surface lubricity, and the like, and a moiety (namely, group in parentheses with δ1) providing a binding ability to the base material, in any compound represented by formula (D). Accordingly, X7 may be a single bond or any organic group as long as such any compound represented by formula (D) can be stably present. Herein, a left portion and a right portion of the structure designated as X7 are bonding to the group represented by PFPE and the group in parentheses with δ1, respectively. [0161] In another embodiment, X7 represents Xe. Xe has the same meaning as described above. [0162] In the formulae, δ1 is an integer of 1 to 9, and δ1 may be varied depending on the valence of X7. In formula (D), δ1 corresponds to a value obtained by subtracting 1 from the valence of X7. In the case where X7 is a single bond, δ1 is 1. [0163] X7 is preferably a di- to heptavalent, more preferably di- to tetravalent, further preferably divalent organic group. [0164] In one embodiment, X7 is a di- to tetravalent organic group, and δ1 is 1 to 3. [0165] In another embodiment, X7 is a divalent organic group, and δ1 is 1. In such a case, formula (D) is represented by the following formula (D'): Rf m2Re l2Rd k2C-X7-PFPE-X7-CRd" k2Re" l2Rf" m2 ··· (D') [0166] Examples of X7 are not limited, and include the same as described with respect to X1. [0167] In particular, preferable specific examples of X7 includea single bond,-CH2OCH2-,-CH2O(CH2)2-,-CH2O(CH2)3-,-CH2O(CH2)6-,-CF2-CH2-O-CH2-,-CF2-CH2-O-(CH2)2-,-CF2-CH2-O-(CH2)3-,-CF2-CH2-O-(CH2)6-,-CH2O(CH2)3Si(CH3)2OSi(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2OSi(CH3)2OSi(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)2Si(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)3Si(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)10Si(CH3)2(CH2)2-,-CH2O(CH2)3Si(CH3)2O(Si(CH3)2O)20Si(CH3)2(CH2)2-,-CH2OCF2CHFOCF2-,-CH2OCF2CHFOCF2CF2- ,-CH2OCF2CHFOCF2CF2CF2-,-CH2OCH2CF2CF2OCF2-,-CH2OCH2CF2CF2OCF2CF2-,-CH2OCH2CF2CF2OCF2CF2CF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2CF2-,-CH2OCH2CHFCF2OCF2-,-CH2OCH2CHFCF2OCF2CF2-,-CH2OCH2CHFCF2OCF2CF2CF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2CF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2CF2CF2-,-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CH2OCH2(CH2)7CH2Si(OCH3)2OSi(OCH3)2(CH2)2Si(OCH3)2OSi(OCH3)2(C H2)2-,-CH2OCH2CH2CH2Si(OCH3)2OSi(OCH3)2(CH2)3-,-CH2OCH2CH2CH2Si(OCH2CH3)2OSi(OCH2CH3)2(CH2)3-,-CH2OCH2CH2CH2Si(OCH3)2OSi(OCH3)2(CH2)2-,-CH2OCH2CH2CH2Si(OCH2CH3)2OSi(OCH2CH3)2(CH2)2-,-(CH2)2-Si(CH3)2-(CH2)2 -,-CH2-,-(CH2)2-,-(CH2)3-,-(CH2)4-,-(CH2)5-,-(CH2)6-,-CF2-,-(CF2)2-,-CF2-CH2-,-CF2-(CH2)2-,-CF2-(CH2)3-,-CF2-(CH2)4-,-CF2-(CH2)5-,-CF2-(CH2)6-,-CO-,-CONH-,-CONH-CH2-,-CONH-(CH2)2-,-CONH-(CH2)3-,-CONH-(CH2)6-,-CF2CONH-,-CF2CONHCH2-,-CF2CONH(CH2)2-,-CF2CONH(CH2)3-,-CF2CONH(CH2)6-,-CON(CH3)-(CH2)3-,-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CON(CH3)-(CH2)6-,-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)3-,-CF2-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)6-,-CF2-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CONH-(CH2)2NH(CH2)3-,-CONH-(CH2)6NH(CH2)3-,-CH2OCONH-(CH2)3-,-CH2O-CONH-(CH2)6-,-S-(CH2)3-,-(CH2)2S(CH2)3-,-CONH-(CH2)3Si(CH3)2OSi(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2OSi(CH3)2OSi(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)2Si(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)3Si(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)OSi(CH3)2(CH2)2-,-CONH-(CH2)3Si(CH3)2O(Si(CH3)2O)20Si(CH3)2(CH2)2-,-C(O)O-(CH2)3-,-C(O)O-(CH2)6-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-(CH2)2-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-CH(CH3)-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-(CH2)3-,-CH2-O-(CH2)3-Si(CH3)2-(CH2)2-Si(CH3)2-CH(CH3)-CH2-,-OCH2-,-O(CH2)3-, and-OCFHCF2- [0168] In particular, specific X7 is more preferably-CH2OCH2-,-CH2O(CH2)2-,-CH2O(CH2)3-,-CH2O(CH2)6-,-CF2-CH2-O-CH2-,-CF2-CH2-O-(CH2)2-,-CF2-CH2-O-(CH2)3-,-CF2-CH2-O-(CH2)6-,-CH2OCF2CHFOCF2-,-CH2OCF2CHFOCF2CF2-,-CH2OCF2CHFOCF2CF2CF2-,-CH2OCH2CF2CF2OCF2-,-CH2OCH2CF2CF2OCF2CF2-,-CH2OCH2CF2CF2OCF2CF2CF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2-,-CH2OCH2CF2CF2OCF(CF3)CF2OCF2CF2CF2-,-CH2OCH2CHFCF2OCF2-,-CH2OCH2CHFCF2OCF2CF2-,-CH2OCH2CHFCF2OCF2CF2CF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2CF2-,-CH2OCH2CHFCF2OCF(CF3)CF2OCF2CF2CF2-,-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CF2-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CH2-,-(CH2)2-,-(CH2)3-,-(CH2)4-,-(CH2)5-,-(CH2)6-,-CF2-,-(CF2)2-,-CF2-CH2-,-CF2-(CH2)2-,-CF2-(CH2)3-,-CF2-(CH2)4-,-CF2-(CH2)5-,-CF2-(CH2)6-,-CONH-,-CONH-CH2-,-CONH-(CH2)2-,-CONH-(CH2)3-,-CONH-(CH2)6-,-CF2CONH-,-CF2CONHCH2-,-CF2CONH(CH2)2-,-CF2CONH(CH2)3-,-CF2CONH(CH2)6-,-CON(CH3)-(CH2)3-,-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CON(CH3)-(CH2)6-,-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)3-,-CF2-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)6-,-CF2-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CONH-(CH2)2NH(CH2)3-,-CONH-(CH2)6NH(CH2)3-,-CH2O-CONH-(CH2)3-,-CH2O-CONH-(CH2)6-,-OCH2-,-O(CH2)3-,-OCFHCF2-. [0169] In particular, X7 is more preferably-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CF2-CH2OCF2CHFOCF2CF2CF2-C(O)NH-CH2-,-CONH-,-CONH-CH2-,-CONH-(CH2)2-,-CONH-(CH2)3-,-CONH-(CH2)6-,-CF2CONH-,-CF2CONHCH2-,-CF2CONH(CH2)2-,-CF2CONH(CH2)3-,-CF2CONH(CH2)6-,-CON(CH3)-(CH2)3-,-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CON(CH3)-(CH2)6-,-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)3-,-CF2-CON(Ph)-(CH2)3-, wherein Ph means phenyl,-CF2-CON(CH3)-(CH2)6-,-CF2-CON(Ph)-(CH2)6-, wherein Ph means phenyl,-CONH-(CH2)2NH(CH2)3-,-CONH-(CH2)6NH(CH2)3-. [0170] In one embodiment, X7 represents Xe' . Xe' has the same meaning as described above. [0171] In one embodiment, Xe' is a single bond. In the present embodiment, PFPE and a group having a binding ability to the base material (namely, group in parentheses with δ1 in formula (D)) are directly bonded. It is considered that such a structure is included to thereby strengthen a bonding force between PFPE and the group in parentheses with δ1. It is also considered that a carbon atom (namely, in the group in parentheses with δ1, a carbon atom bonding to Rd, Re and Rf or a carbon atom bonding to Rd", Re" and Rf") directly bonding to PFPE is less biased in charge and, as a result, a nucleophilic reaction or the like hardly occurs at the carbon atom and the compound is stably bonding to the base material. Such a structure has the advantage of being capable of more enhancing friction durability of a layer formed by the PFPE-containing silane compound. [0172] In the formulae, each Rd, at each occurrence, independently represents -Z4-CR81 p2R82 q2R83 r2. [0173] In the formulae, each Z4, at each occurrence, independently represents an oxygen atom or a divalent organic group. [0174] Z4 is preferably a C1-6 alkylene group, -(CH2)g-O-(CH2)h-, wherein g is an integer of 0 to 6, for example, an integer of 1 to 6, and h is an integer of 0 to 6, for example, an integer of 1 to 6, or -phenylene-(CH2)i-, wherein i is an integer of 0 to 6, more preferably a C1-3 alkylene group. Such a group is optionally substituted with one or more substituents selected from, for example, a fluorine atom, a C1-6 alkyl group, a C2-6 alkenyl group and a C2-6 alkynyl group. [0175] In the formulae, each R81, at each occurrence, independently represents Rd'. Rd' has the same meaning as Rd. [0176] The number of C linearly linked via a Z4 group is at most 5 in Rd. That is, in the case where at least one R81 is present in Rd, two or more C atoms linearly linked via a Z4 group are present in Rd, and the number of such C atoms linearly linked via a Z4 group is at most 5. Herein, the "number of C atoms linearly linked via a Z4 group in Rd" is equal to the number of repeating units of -Z4-C- linearly linked in Rd. [0177] In a preferable embodiment, the "number of C atoms linearly linked via a Z4 group in Rd" is 1 (left formula) or 2 (right formula) in all chains, as represented below. [0178] In one embodiment, the number of C atoms linearly linked via a Z4 group in Rd is 1 or 2, preferably 1. [0179] In the formulae, each R82, at each occurrence, independently represents -Y-SiR85 n2R86 3-n2. [0180] Each Y, at each occurrence, independently represents a divalent organic group. [0181] In a preferable embodiment, Y is a C1-6 alkylene group, - (CH2)g'-O-(CH2)h'-, wherein g' is an integer of 0 to 6, for example, an integer of 1 to 6, and h' is an integer of 0 to 6, for example, an integer of 1 to 6, or -phenylene-(CH2)i'-, wherein i' is an integer of 0 to 6. Such a group is optionally substituted with one or more substituents selected from, for example, a fluorine atom, a C1-6 alkyl group, a C2-6 alkenyl group and a C2-6 alkynyl group. [0182] In one embodiment, Y can be a C1-6 alkylene group or -phenylene-(CH2)i'-. In the case where Y is any of the above groups, light resistance, in particular, ultraviolet resistance can be more enhanced. [0183] Each R85, at each occurrence, independently represents a hydroxyl group or a hydrolyzable group. [0184] Examples of the "hydrolyzable group" include the same as in formula (C). [0185] Preferably, R85 is -OR, wherein R represents a substituted or unsubstituted C1-3 alkyl group, more preferably an ethyl group or a methyl group, in particular, a methyl group. [0186] Each R86, at each occurrence, independently represents a hydrogen atom or a lower alkyl group. The lower alkyl group is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, further preferably a methyl group. [0187] n2 with respect to a (-Y-SiR85 n2R86 3-n2) unit or with respect to a (-Y-SiR85" n2R86" 3-n2) unit independently represents an integer of 0 to 3, preferably an integer of 1 to 3, more preferably 2 or 3, particularly preferably 3. R85" and R86" are described below. [0188] Each R83, at each occurrence, independently represents a hydrogen atom, a hydroxyl group or a lower alkyl group, preferably a hydrogen atom or a lower alkyl group. The lower alkyl group is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, further preferably a methyl group. [0189] In the formulae, each p2, at each occurrence, is independently an integer of 0 to 3; each q2, at each occurrence, is independently an integer of 0 to 3; and each r2, at each occurrence, is independently an integer of 0 to 3, provided that the sum of p2, q2 and r2 with respect to (-Z4-CR81 p2R82 q2R83 r2) or with respect to (-Z4-CR81 p2R82" q2R83 r2) is 3. R82" is described below. [0190] In a preferable embodiment, in Rd' at an end of Rd (Rd in the case where no Rd' is present), q2 is preferably 2 or more, for example, 2 or 3, more preferably 3. [0191] In a preferable embodiment, at least one end of Rd can be -C(-Y-SiR85 n2R86 3-n2)2 (specifically, -C(-Y-SiR85 n2R86 3-n2)2R83) or -C(-Y-SiR85 n2R86 3-n2)3, preferably -C(-Y-SiR85 n2R86 3-n2)3. Here, n2 is an integer of 1 to 3. In the formulae, a (-Y-SiR85 n2R86 3-n2) unit is preferably (-Y-SiR85 3). In a further preferable embodiment, all ends of Rd can be each -C(-Y-SiR85 n2R86 3-n2)3, preferably -C(-Y-SiR85 3)3. [0192] In a more preferable embodiment, an end of a group represented by (CRd k2Re l2Rf m2) is C(-Y-SiR85 n2R86 3-n2)2Rf), C(-Y-SiR85 n2R86 3-n2)2R83 or C(-Y-SiR85 n2R86 3-n2)3, preferably C(-Y-SiR85 n2R86 3-n2)3. Here, n2 is an integer of 1 to 3. In the formulae, a (-Y-SiR85 n2R86 3-n2) unit is preferably (-Y-SiR85 3). In a further preferable embodiment, all ends of the group can be each -C(-Y-SiR85 n2R86 3-n2)3, preferably-C(-Y-SiR85 3)3. [0193] In the formulae, each Rd", at each occurrence, independently represents -Z4-CR81 p2R82" q2R83 r2. Z4, R81, R83, p2, q2 and r2 have the same meanings as described above. Each R82", at each occurrence, independently represents - Y-SiR85" n2R86" 3-n2. Here, Y and n2 have the same meanings as described above. R85" and R86" have the same meanings as R85 and R86, respectively. [0194] In a preferable embodiment, in Rd' at an end of Rd" (Rd" in the case where no Rd' is present), q2 is preferably 2 or more, for example, 2 or 3, more preferably 3. [0195] In a preferable embodiment, at least one end of Rd" can be -C(-Y-SiR85" n2R86" 3-n2)2 (specifically, -CR81 P2(-Y-SiR85" n2R86" 3-n2)2R83) or -C(-Y-SiR85" n2R86" 3-n2)3, preferably-C(-Y-SiR85" n2R86" 3-n2)3. Here, n2 is an integer of 1 to 3. In the formulae, a (-Y-SiR85" n2R86" 3-n2) unit is preferably (-Y-SiR85"3) . In a further preferable embodiment, all ends of Rd can be each -C(-Y-SiR85" n2R86" 3-n2)3, preferably-C(-Y-SiR85" 3)3. [0196] In a more preferable embodiment, an end of a group represented by (CRd" k2Re" l2Rf" m2) is C(-Y-SiR85" n2R86" 3-n2)2Rf, C(-Y-SiR85" n2R86" 3-n2)2R83 or C(-Y-SiR85" n2R86" 3-n2)3, preferably C(-Y-SiR85" n2R86" 3-n2)3. Here, n2 is an integer of 1 to 3. In the formulae, a (-Y-SiR85" n2R86" 3-n2) unit is preferably (-Y-SiR85"3). In a further preferable embodiment, all ends of the group can be each -C(-Y-SiR85" n2R86" 3-n2)3, preferably -C(-Y-SiR85" 3)3. [0197] In the formulae, each Re, at each occurrence, independently represents -Y-SiR85 n2R86 3-n2. Here, Y, R85, R86 and n2 have the same meanings as described in R82. [0198] In the formulae, each Re", at each occurrence, independently represents -Y-SiR85" n2R86" 3-n2. Here, R85", R86", Y, and n2 have the same meanings as described above. [0199] In the formulae, each Rf, at each occurrence, independently represents a hydrogen atom, a hydroxyl group or a lower alkyl group. Preferably, each Rf, at each occurrence, independently represents a hydrogen atom or a lower alkyl group. The lower alkyl group is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, further preferably a methyl group. [0200] In the formulae, Rf" has the same meaning as Rf. [0201] In the formulae, each k2, at each occurrence, is independently an integer of 0 to 3; each 12, at each occurrence, is independently an integer of 0 to 3; and each m2, at each occurrence, is independently an integer of 0 to 3, provided that the sum of k2, l2 and m2 is 3. [0202] In one embodiment, at least one k2 is 2 or 3, preferably 3. [0203] In one embodiment, k2 is 2 or 3, preferably 3. [0204] In one embodiment, 12 is 2 or 3, preferably 3. [0205] In formula (D), two or more groups selected from the group consisting of a group represented by -Y-SiR85 and a group represented by -Y-SiR85" are present. In formula (D), preferably, one or more groups represented by -Y-SiR85 and one or more groups represented by -Y-SiR85" are present. More preferably, one or more carbon atoms bonding to two or more groups each represented by -Y-SiR85 are present, and one or more carbon atoms bonding to two or more groups each represented by -Y-SiR85" are present. That is, one or more groups selected from a group represented by -C-Rd k2(Y-SiR85 n2R86 3-n2)l2Rf m2 (provided that 12 is 2 or 3 and the total of k2, l2 and m2 is 3) and a group represented by -C-R81 p2(Y-SiR85 n2R86 3-n2)q2R83 r2 (provided that q2 is 2 or 3 and the total of p2, q2 and r2 is 3), and one or more groups selected from a group represented by -C-Rd k2(Y-SiR85" n2R86" 3-n2)l2Rf m2 (provided that 12 is 2 or 3 and the total of k2, l2 and m2 is 3) and a group represented by -C-R81 p2 (Y-SiR85" n2R86" 3-n2)q2R83 r2 (provided that q2 is 2 or 3 and the total of p2, q2 and r2 is 3), wherein n2 is an integer of 1 to 3, are preferably present in formula (D). [0206] In one embodiment, one or more groups represented by -C-(Y-SiR85 n2R86 3-n2)2 and one or more groups represented by -C-(Y-SiR85" n2R86" 3-n2)2, wherein n2 is an integer of 1 to 3, are preferably present in formula (D). [0207] In one embodiment, one or more groups represented by -C-(Y-SiR85 n2R86 3-n2)3 and one or more groups represented by -C-(Y-SiR85" n2R86" 3-n2)3, wherein n2 is an integer of 1 to 3, are preferably present in formula (D). [0208] In formula (D), n2 is an integer of 1 to 3 and at least one q2 is 2 or 3, or at least one 12 is 2 or 3. [0209] In formula (D), at least two of -Y-SiR85 n2R86 3-n2 group and -Y-SiR85" n2R86" 3-n2 group are preferably present. In formula (D), one or more -Y-SiR85 n2R86 3-n2 groups and one or more -Y-SiR85" n2R86" 3-n2 groups are more preferably present. That is, a group represented by -SiR85 and a group represented by -SiR85" are preferably present at both respective ends of a molecular backbone of the PFPE-containing silane compound (A). [0210] The compound represented by formula (D) can be produced by combining known methods. [0211] In a preferable embodiment, the PFPE-containing silane compound (A) is represented by formula (B) or (C). [0212] The PFPE-containing silane compound (A) can have a number average molecular weight of 5 × 102 to 1 × 105, without any limitation. In particular, the compound preferably has a number average molecular weight of 2,000 to 30,000, more preferably 2,500 to 12,000, further preferably 3,000 to 6,000. In the present invention, the number average molecular weight is defined as a value obtained by 19F-NMR measurement. [0213] In one embodiment, the PFPE-containing silane compound (A) can be a compound represented by formula (A), (C) or (D). Such a silane compound can be used to thereby allow adhesion properties to the base material to be enhanced. [0214] In another preferable embodiment, on at least one end the PFPE-containing silane compound (A), there is two or more, preferably three or more Si atoms each having a hydroxyl group or a hydrolyzable group. (Cross-linking agent) [0215] The cross-linking agent is not limited as long as the agent is a compound having a portion which can undergo a crosslinking reaction (condensation reaction) with the fluorine-containing silane compound (for example, PFPE-containing silane compound (A), specifically, a silane moiety having a hydroxyl group or a hydrolyzable group bonding to a Si atom of the PFPE-containing silane compound (A)). The fluorine-containing silane compound (for example, PFPE-containing silane compound (A)) and the cross-linking agent can be included, thereby improving physical properties (for example, tensile strength and elastic modulus) of a cured product obtained from the curable composition of the present invention. [0216] The cross-linking agent is an organosilicon compound having at least two -O-Rg3(s) each bonding to a Si atom. In the formula, each Rg3, at each occurrence, independently represents a hydrogen atom or a monovalent organic group. The monovalent organic group means a carbon atom-containing group. Such a monovalent organic group is not limited, and examples thereof include a group where one hydrogen atom is further removed from a hydrocarbon group. The hydrocarbon group has the same meaning as described above. [0217] The cross-linking agent has a structure different from that of the fluorine-containing silane compound (specifically, PFPE-containing silane compound (A)). [0218] Examples of the cross-linking agent can include an organic compound where Rg3 is a hydrogen atom, namely, an organosilicon compound having at least two silanol groups in one molecule, and any organosilicon compound represented by formulae (E3) to (E5) described below. [0219] Organosilicon compound having at least two silanol groups in one molecule:Such silanol groups are preferably present at both respective ends of a molecular backbone in the organosilicon compound. The molecular backbone here represents a relatively longest binding chain in a molecule of the organosilicon compound. [0220] Examples of the compound having silanol groups at both respective ends of a molecular backbone can include a compound represented by the following formula (E1) or (E2) . [0221] In formula (E1) or (E2), each Rg1, at each occurrence, is independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms. Specific examples of Rg1 include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group and a decyl group; cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group and a cycloheptyl group; alkenyl groups such as a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a hexenyl group and a cyclohexenyl group; aryl groups such as a phenyl group, a tolyl group, a xylyl group and a naphthyl group; aralkyl groups such as a benzyl group, a phenylethyl group and a phenylpropyl group; and groups where some or all hydrogen atoms of such a group are substituted with a halogen atom (for example, a chloromethyl group, a bromoethyl group, a chloropropyl group, a trifluoropropyl group and a nonafluorohexyl group). [0222] In formula (E1) or (E2), each Rg2, at each occurrence, is independently a substituted or unsubstituted divalent hydrocarbon group having 1 to 20 carbon atoms, preferably 2 to 10 carbon atoms. Specific examples of Rg2 include alkylene groups such as a methylene group, an ethylene group, a propylene group, a methylethylene group, a butylene group and a hexamethylene group; cycloalkylene groups such as a cyclohexylene group, arylene groups such as a phenylene group, a tolylene group, a xylylene group, a naphthylene group and a biphenylene group; a group where some or all hydrogen atoms of such a group are substituted with a halogen atom; and a combination of such a substituted or unsubstituted alkylene group and an arylene group. Among them, Rg2 is preferably a methylene group, an ethylene group, a propylene group, a butylene group, a hexamethylene group, a cyclohexylene group or a phenylene group, and is particularly preferably an ethylene group, a propylene group, a butylene group or a phenylene group. Examples of the compound having silanol groups in a molecule include a resin compound including a bond of one unit of Rg1 3SiO1/2, Rg1 2SiO, Rg1SiO3/2, and SiO2, or a combination of two or more kinds thereof, with a silanol group. Constituent units of the resin compound may be directly bonded or may be bonded via a di- or higher valent hydrocarbon group. [0223] In formula (E1) or (E2), each ε1, at each occurrence, is independently an integer of 1 or more, and ε1 is preferably 2 or more, more preferably 5 or more, preferably 50 or less, more preferably 20 or less. [0224] The organosilicon compound having at least two silanol groups in one molecule (specifically, compound represented by formula (E1) or (E2)) preferably has no PFPE structure in a molecular structure. [0225] Any organosilicon compound represented by formula (E3), (E4) or (E5): (Rg3-O)ε2-Si-Rg4 4-ε2 ··· (E3) [0226] In formulae (E3) and (E4), Rg3 has the same meaning as described above. Rg3 is a portion which can react with a portion having a hydroxyl group or a hydrolyzable group bonding to a Si atom of the PFPE-containing silane compound (A) represented by formula (A), (B), (C) or (D). [0227] Rg3 is preferably a monovalent organic group. [0228] Each Rg3-, at each occurrence, is more preferably independently CH3-, C2H5-, C3H7-, CF3CH2-, CH3CO-, CH2=C(CH3)-, CH3CH2C(CH3)=N-, (CH3)2N-, (C2H5)2N-, CH2=C(OC2H5)-, (CH3)2C=C(OC8H17)-, or [0229] In formulae (E3) and (E4), each Rg4, at each occurrence, is independently a monovalent organic group. Rg4 is preferably a substituted or unsubstituted monovalent hydrocarbon group, more preferably a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms. Specific examples of Rg4 can include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group and a decyl group; cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group and a cycloheptyl group; aryl groups such as a phenyl group, a tolyl group, a xylyl group and a naphthyl group; aralkyl groups such as a benzyl group, a phenylethyl group and a phenylpropyl group; alkenyl groups such as a vinyl group, an allyl group, a propenyl group and a butenyl group; and groups where some or all hydrogen atoms of such a group are substituted with a halogen atom such as fluorine, chlorine or bromine (for example, a chloromethyl group, a bromoethyl group, a chloropropyl group, a trifluoropropyl group and a 3,3,4,4,5,5,6,6,6-nonafluorohexyl group). [0230] In one embodiment, Rg4 can be a group represented by the following general formula. Rf1-Rg5- [0231] In the formulae, Rf1 is a monovalent fluorinated polyether group. Examples of Rf1 include one having a structure where CF3O-, CF3CF2O-, CF3CF2CF2O-, (CF3)2CFO-, CF3CF2CF2CF2O- or the like is bonding to a CF2 end of PFPE above. [0232] Rg5 is a divalent organic group. The divalent organic group has the same meaning as described above. [0233] Rg5 can be a substituted or unsubstituted divalent hydrocarbon group, for example, optionally containing one or more of an oxygen atom, a nitrogen atom, a silicon atom and a sulfur atom, and optionally containing an amide bond or a sulfonamide bond. The divalent hydrocarbon group preferably has 2 to 20 carbon atoms. Specific examples of a substituted or unsubstituted divalent hydrocarbon group not having any oxygen atom, nitrogen atom, silicon atom or sulfur atom interposed and not containing any amide bond or sulfonamide bond include alkylene groups such as an ethylene group, a propylene group, a methylethylene group, a butylene group and a hexamethylene group; cycloalkylene groups such as a cyclohexylene group; arylene groups such as a phenylene group, a tolylene group, a xylylene group, a naphthylene group and a biphenylene group; a combination of any alkylene group and any arylene group; and a group where some or all hydrogen atoms of such alkylene group and arylene group are substituted with a halogen atom. [0234] The divalent hydrocarbon group can contain an oxygen atom in the form of -O-, a nitrogen atom in the form of - NRg51- (Rg51 is a hydrogen atom or an alkyl group or aryl group having 1 to 10 carbon atoms) or -N=, a silicon atom in the form of -SiRg52Rg53- (Rg52 and Rg53, at each occurrence, are each independently an alkyl group or aryl group having 1 to 10 carbon atoms), and/or a sulfur atom in the form of -S-. The divalent hydrocarbon group can contain an amide bond in the form of -C(=O)NRg51- (Rg51 is the same as described above) and/or a sulfonamide bond in the form of -SO2NRg51- (Rg51 is the same as described above). Specific examples of such a divalent hydrocarbon group include the following. In the following formulae, Me represents a methyl group and Ph represents a phenyl group, and an Rf1 group is bonding to a left portion of each of the following formulae. [0235] J-CH2CH2OCH2CH2CH2-, J-CH2OCH2CH2CH2-, [0236] In formulae (E3) and (E4), each ε2, at each occurrence, is independently 2 or 3, and each ε3, at each occurrence, is independently 2 or 3. [0237] In formula (E5), Rg3 and Rg4 have the same meanings as described above. In formula (E5), each Rg6-, at each occurrence, independently represents Rg8-Rg7-. [0238] Each Rg7, at each occurrence, independently represents a single bond an oxygen atom or a divalent organic group. The divalent organic group is as described above. [0239] Rg7 is preferably an alkylene group having 1 to 10 carbon atoms or a group having 1 to 10 carbon atoms and containing a nitrogen atom or an oxygen atom in a main chain. [0240] Rg7 is more preferablyan alkylene group having 1 to 3 carbon atoms, CH2CH2-NH-CH2CH2CH2, orCH2-O-CH2CH2CH2. [0241] Rg8 is a reactive functional group. Each Rg8, at each occurrence, is preferably independently an amino group, an epoxy group, a methacrylic group, a vinyl group or a mercapto group, more preferably an amino group. [0242] In formula (E5), ε4 is an integer of 2 or more, preferably 2 or 3, more preferably 3. In formula (E5), ε5 is an integer of 0 or more, preferably 0 or 1. In formula (E5), ε6 is 1 or 2, preferably 1, provided that the sum of ε4, ε5 and ε6 is 4. [0243] In formula (E5), preferably ε4 is 2 or 3, ε5 is 0 or 1 and ε6 is 1 or 2, more preferably ε4 is 3, ε5 is 0 and ε6 is 1. [0244] Preferably, the cross-linking agent is any compound represented by formula (E3) or formula (E5), more preferably any compound represented by formula (E3). [0245] In one embodiment, the cross-linking agent does not have any group represented by PFPE in a molecular chain. [0246] In one embodiment, the molecular weight of the cross-linking agent is 1000 or less, preferably 600 or less, more preferably 250 or less. The lower limit of the molecular weight of the cross-linking agent may be 50 or more or 100 or more. [0247] In a preferable embodiment, the cross-linking agent is at least one selected from the group consisting of tetraethoxysilane, tetratrimethoyxsilane, methyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, dimethyltrimethoxysilane, aminopropyltriethoxysilane, aminopropyltrimethoxysilane, tridecafluoro-n-octyltriethoxysilane and tridecafluoro-n-octyltrimethoxysilane. [0248] The cross-linking agent may be used singly or in combinations of two or more kinds thereof. [0249] The curable composition of the present invention can include, for example, 0.1 parts by mass or more, specifically 0.3 parts by mass or more, and 30 parts by mass or less, specifically 10 parts by mass or less of the cross-linking agent based on 100 parts by mass of the PFPE-containing silane compound (a). [0250] The curable composition of the present invention can include, for example, 0.1 to 30 parts by mass, specifically 0.3 to 10 parts by mass of the cross-linking agent based on 100 parts by mass of the PFPE-containing silane compound (A). [0251] The curable composition of the present invention more preferably includes the cross-linking agent in the range from 0.01 to 30 parts by mass, more preferably in the range from 0.1 to 10.0 parts by mass based on 100 parts by mass of the curable composition of the present invention. (Metal-based catalyst) [0252] The metal-based catalyst is represented by M(-O-Rh)η, wherein M represents a metal atom, each Rh, at each occurrence, is independently a hydrocarbon group having 1 to 3 carbon atoms, and η is the coordination number of M. Such a metal-based catalyst is used to thereby promote a condensation reaction of the fluorine-containing silane compound (for example, PFPE-containing silane compound (A)) and the cross-linking agent. Such a metal-based catalyst can be easily dissolved or dispersed in the curable composition and can contribute to promotion of a reaction uniformly. The curable composition of the present invention, which includes such a metal-based catalyst, can include less foreign substances and can contribute to formation of a cured product of the curable composition, having high transparency. [0253] M is preferably at least one selected from the group consisting of titanium, zirconium and tin. [0254] In a preferable embodiment, M is a titanium atom or a zirconium atom. The curable composition of the present invention contains such a metal atom as M and thus can be particularly suitable in an electronic material application (for example, semiconductor application or information terminal) or an automobile application. The curable composition of the present invention contains such a metal atom and thus can be reduced in environmental load. [0255] Rh is a hydrocarbon group having 1 to 3 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms. The alkyl group having 1 to 3 carbon atoms is, namely, a methyl group, an ethyl group, a n-propyl group or an i-propyl group. [0256] η is the coordination number of the metal atom M. η is preferably an integer of 1 to 8. For example, in the case where M is a titanium atom or a zirconium atom, η is 4. [0257] Examples of a preferable metal-based catalyst can include at least one selected from the group consisting of tetrapropyl titanate and tetrapropyl zirconate. Examples of the tetrapropyl titanate can include tetraisopropyl titanate (tetraisopropaxy titanium) and tetra-n-propyl titanate, and examples of the tetrapropyl zirconate can include tetraisopropyl zirconia and tetra-n-propyl zirconate. Such a metal-based catalyst is particularly easily dissolved or dispersed in the curable composition and can contribute to promotion of a reaction uniformly. The curable composition, which includes such a metal-based catalyst, can include less foreign substances and can contribute to formation of a cured product of the curable composition, having high transparency. [0258] The curable composition of the present invention preferably includes 0.05 parts by mass or more, more preferably 0.07 parts by mass or more of the metal-based catalyst based on 100 parts by mass of the fluorine-containing silane compound (for example, PFPE-containing silane compound (A)). The curable composition of the present invention preferably includes 5.0 parts by mass or less, more preferably 1.0 part by mass or less of the metal-based catalyst based on 100 parts by mass of the fluorine-containing silane compound (for example, PFPE-containing silane compound (A)). The curable composition includes the concentration of the metal-based catalyst, thereby allowing a condensation reaction of the fluorine-containing silane compound and the cross-linking agent to be particularly promoted. [0259] The curable composition of the present invention preferably includes 0.05 to 5.0 parts by mass, more preferably 0.07 to 1.0 parts by mass of the metal-based catalyst based on 100 parts by mass of the fluorine-containing silane compound (for example, PFPE-containing silane compound (A)). [0260] The metal-based catalyst may be used singly or simultaneously in combination of two or more kinds thereof. (Solvent) [0261] The curable composition of the present invention may include a solvent. In such a case, the curable composition can be used, with being dissolved in a proper solvent (for example, a fluorine atom-containing solvent) so as to have a desired concentration depending on the application and the intended use. The concentration of the solvent may be, for example, 80 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, 20 parts by mass or less based on 100 parts by mass of the curable composition. [0262] Examples of the solvent include:a fluorine atom-containing solvent selected from the group consisting of perfluorohexane, CF3CF2CHCl2, CF3CH2CF2CH3, CF3CHFCHFC2F5, 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecafluorooctane, 1,1,2,2,3,3,4-heptafluorocyclopentane ((Zeorora H (trade name) or the like), C4F9OCH3, C4F9OC2H5, CF3CH2OCF2CHF2, C6F13CH=CH2, xylene hexafluoride, perfluorobenzene, methylpentadecafluoroheptylketone, trifluoroethanol, pentafluoropropanol, hexafluoroisopropanol, HCF2CF2CH2OH, methyltrifluoromethanesulfonate, trifluoroacetic acid, CF3O(CF2CF2O)m1(CF2O)n1CF2CF3, wherein m1 and n1 are each independently an integer of 0 or more and 1000 or less and the occurrence order of the respective repeating units in parentheses with m1 or n1 is not limited in the formula, provided that the sum of m1 and n1 is 1 or more, 1,1-dichloro-2,3,3,3-tetrafluoro-1-propene, 1,2-dichloro-1,3,3,3-tetrafluoro-1-propene, 1,2-dichloro-3,3,3-trifluoro-1-propene, 1,1-dichloro-3,3,3-trifluoro-1-propene, 1,1,2-trichloro-3,3,3-trifluoro-1-propene, 1,1,1,4,4,4-hexafluoro-2-butene, ethyl perfluorobutyl ether and methyl perfluorobutyl ether. Such a solvent may be used singly or as a mixture of two or more kinds thereof. [0263] Herein, various primers can also be used in combination in the case where the cured product obtained from the curable composition of the present invention is allowed to adhere to various base materials. [0264] In one embodiment, the curable composition of the present invention, when used, may be further diluted with a solvent and thus used, depending on the application and the intended use. Any of the fluorine-based solvents exemplified above can be used as the solvent for use in the dilution. For example, the composition may be used, with being dissolved in a solvent such as 1,3-bis(trifluoromethyl)benzene, Fluorinert (manufactured by 3M), perfluorobutyl methyl ether or perfluorobutyl ethyl ether so that a desired concentration is achieved. In particular, the solvent is preferably used in the application of thin film coating. [0265] The curable composition of the present invention can further include any compound represented by the following formula (A1), (B1), (C1) or (D1). [0266] Any portion of the descriptions of formulae (A1), (B1), (C1) and (D1), overlapped with those of (A), (B), (C) and (D), will be omitted. [0267] In the formulae, Rf, at each occurrence, independently represents an alkyl group having 1 to 16 carbon atoms, optionally substituted with one or more fluorine atoms. [0268] The "alkyl group having 1 to 16 carbon atoms" with respect to the alkyl group having 1 to 16 carbon atoms, the group being optionally substituted with one or more fluorine atoms, is optionally linear or branched, is preferably a linear or branched alkyl group having 1 to 6 carbon atoms, particularly 1 to 3 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms. [0269] Rf is preferably an alkyl group having 1 to 16 carbon atoms, the group being optionally substituted with one or more fluorine atoms, more preferably a CF2H-C1-15 fluoroalkylene group or a C1-16 perfluoroalkyl group, further preferably a C1-16 perfluoroalkyl group. [0270] The perfluoroalkyl group having 1 to 16 carbon atoms may be linear or branched, and is preferably a linear or branched perfluoroalkyl group having 1 to 6 carbon atoms, in particular, 1 to 3 carbon atoms, more preferably a linear perfluoroalkyl group having 1 to 3 carbon atoms, specifically -CF3, -CF2CF3, or -CF2CF2CF3. [0271] In formula (A1), α1 is an integer of 1 to 9 and α1' is an integer of 1 to 9. Here, α1' may be varied depending on the valence of X1. In formula (A1), the sum of α1 and α1' is the same as the valence of X1. For example, in the case where X1 is a decavalent organic group, the sum of α1 and α1' can be 10, for example, α1 can be 9 and α1' can be 1, α1 can be 5 and α1' can be 5, or α1 can be 1 and α1' can be 9. In the case where X1 is a divalent organic group, α1 and α1' are 1. In the case where X1 is a single bond, α1 and α1' are 1. [0272] X1 is preferably a di- to heptavalent, more preferably di- to tetravalent, further preferably divalent organic group. [0273] In one embodiment, X1 is a di- to tetravalent organic group, α1 is 1 to 3, and α1' is 1. [0274] In another embodiment, X1 is a divalent organic group, α1 is 1, and α1' is 1. [0275] In formula (A1), n1' with respect to a (-SiR13 n1'R14 3-n1') unit is independently an integer of 0 to 3, preferably 1 to 3, more preferably 3. In the formula, at least one n1' is an integer of 1 to 3, namely, there is not any case where all n1'(s) are simultaneously 0. In other words, at least one R13 is present in formula (A1). [0276] In formula (B1), β1 is an integer of 1 to 9 and β1' is an integer of 1 to 9. Such β1 and β1' may be varied depending on the valence of X3. In formula (B1), the sum of β1 and β1' is the same as the valence of, X3. For example, in the case where X3 is a decavalent organic group, the sum of β1 and β1' can be 10, for example, β1 can be 9 and β1' can be 1, β1 can be 5 and β1' can be 5, or β1 can be 1 and β1' can be 9. In the case where X3 is a divalent organic group, β1 and β1' are 1. In the case where X3 is a single bond, β1 and β'1 are 1. [0277] X3 is preferably a di- to heptavalent, more preferably di- to tetravalent, further preferably divalent organic group. [0278] In one embodiment, X3 is a di- to tetravalent organic group, β1 is 1 to 3, and β1' is 1. [0279] In another embodiment, X3 is a divalent organic group, β1 is 1, and β1' is 1. [0280] In formula (B1), n1' has the same meaning as described with respect to (A1). [0281] In formula (C1), γ1 is an integer of 1 to 9 and γ1' is an integer of 1 to 9. Such γ1 and γ1' may be varied depending on the valence of X5. In formula (C1), the sum of γ1 and γ1' is the same as the valence of X5. For example, in the case where X5 is a decavalent organic group, the sum of γ1 and γ1' can be 10, for example, γ1 can be 9 and γ1' can be 1, γ1 can be 5 and γ1' can be 5, or γ1 can be 1 and γ1' can be 9. In the case where X5 is a divalent organic group, γ1 and γ1' are 1. In the case where X5 is a single bond, γ1 and γ'1 are 1. [0282] X5 is preferably a di- to heptavalent, more preferably di- to tetravalent, further preferably divalent organic group. [0283] In one embodiment, X5 is a di- to tetravalent organic group, γ1 is 1 to 3, and γ1' is 1. [0284] In another embodiment, X5 is a divalent organic group, γ1 is 1, and γ1' is 1. [0285] In formula (D1), δ1 is an integer of 1 to 9 and δ1' is an integer of 1 to 9. Such δ1 and δ1' may be varied depending on the valence of X7. In formula (D1), the sum of δ1 and δ1' is the same as the valence of X7. For example, in the case where X7 is a decavalent organic group, the sum of δ1 and δ1' can be 10, for example, δ1 can be 9 and δ1' can be 1, δ1 can be 5 and δ1' can be 5, or δ1 can be 1 and δ1' can be 9. In the case where X7 is a divalent organic group, δ1 and δ1' are 1. In the case where X7 is a single bond, δ1 and δ'1 are 1. [0286] X7 is preferably a di- to heptavalent, more preferably di- to tetravalent, further preferably divalent organic group. [0287] In one embodiment, X7 is a di- to tetravalent organic group, δ1 is 1 to 3, and δ1' is 1. [0288] In another embodiment, X7 is a divalent organic group, δ1 is 1, and δ1' is 1. [0289] In one embodiment, the compound represented by formula (A1), (B1), (C1) or (D1) is preferably a compound represented by formula (A1), (C1) or (D1). Such a silane compound can be used to thereby allow adhesion properties to the base material to be enhanced. [0290] In one embodiment, the curable composition of the present invention includes 0.1% by mol or more and 35% by mol or less of any compound represented by formulae (A1), (B1), (C1) and (D1) based on the total of any compound represented by formulae (A), (B), (C) and (D) (hereinafter, also referred to as "component (1)") and any compound represented by formulae (A1), (B1), (C1) and (D1) (hereinafter, also referred to as "component (2)"). The lower limit of the content of any compound represented by formulae (A1), (B1), (C1) and (D1) based on the total of the component (1) and the component (2) can be preferably 0.1% by mol, more preferably 0.2% by mol, further preferably 0.5% by mol, still more preferably 1% by mol, particularly preferably 2% by mol, particularly 5% by mol. The upper limit of the content of any compound represented by formulae (A1), (B1), (C1) and (D1) based on the total of the component (1) and the component (2) can be preferably 35% by mol, more preferably 30% by mol, further preferably 20% by mol, still more preferably 15% by mol or 10% by mol. Any compound represented by formulae (A1), (B1), (C1) and (D1) based on the total of the component (1) and the component (2) is preferably 0.1% by mol or more and 30% by mol or less, more preferably 0.1% by mol or more and 20% by mol or less, further preferably 0.2% by mol or more and 10% by mol or less, still more preferably 0.5% by mol or more and 10% by mol or less, particularly preferably 1% by mol or more and 10% by mol or less, for example, 2% by mol or more and 10% by mol or less or 5% by mol or more and 10% by mol or less. The component (1) and the component (2) can be included in such a range, thereby allowing the curable composition of the present invention to contribute to formation of a cured product favorable in friction durability. [0291] The combination of the component (1) and the component (2) in the curable composition is preferably a combination of a compound represented by formula (A) and a compound represented by formula (A1), a combination of a compound represented by formula (B) and a compound represented by formula (B1), a combination of a compound represented by formula (C) and a compound represented by formula (C1), or a combination of a compound represented by formula (D) and a compound represented by formula (D1). [0292] In such any compound represented by formula (A) and formula (A1), t is preferably 2 or more, more preferably an integer of 2 to 10, further preferably an integer of 2 to 6. Here, t can be 2 or more, thereby allowing a plurality of Si atoms each having R13 or R13" to be present and allowing a cured product formed from the curable composition of the present invention to achieve higher durability (for example, friction durability). [0293] In such any compound represented by formula (C) and formula (C1), k1 is preferably 2 or 3, more preferably 3. [0294] In a preferable embodiment, the compound represented by formula (C) has a structure represented by -Si-(Z3-SiR72 3)2, -Si-(Z3-SiR72"3)2, -Si-(Z3-SiR72 3)3 or -Si-(Z3-SiR72"3)3, further preferably has a structure represented by -Si-(Z3-SiR72 3)3 or -Si-(Z3-SiR72"3)3 at an end; the compound represented by formula (C1) has a structure represented by -Si-(Z3-SiR72 3)2 or -Si-(Z3-SiR72 3)3, further preferably has a structure represented by -Si-(Z3-SiR72 3)3 at an end. Such a structure can be at an end, thereby allowing a cured product formed from the curable composition of the present invention to achieve higher durability (for example, friction durability). [0295] Specific examples of the group represented by -Si-(Z3-SiR72 3)2 or -Si-(Z3-SiR72"3)2 can include-Si-Ra 2Rb l1Rc m1 wherein Ra is a group represented by-Z3-SiR72 3 and the sum of l1 and m1 is 1,-Si-Ra"2Rb"l1Rc"m1 wherein Ra" is a group represented by -Z3-SiR72" 3 and the sum of l1 and m1 is 1,-Si-R71 2R72 q1R73 r1 wherein R71 is a group represented by -Z3-SiR72 3 and the sum of q1 and r1 is 1, or-Si-R71 2R72"q1R73 r1 wherein R71 is a group represented by -Z3-SiR72 3 and the sum of q1 and r1 is 1. [0296] In such any compound represented by formula (D) and formula (D1), 12 is preferably 2 or 3, more preferably 3. [0297] In a preferable embodiment, the compound represented by formula (D) has a -C-(Y-SiR85 3)2, -C-(Y-SiR85"3)2 (specifically, -C-(Y-SiR85 3)2R83, -C-(Y-SiR85"3)2R83), -C-(Y-SiR85)3 or -C-(Y-SiR85")3 structure, further preferably a-C-(Y-SiR85)3 or -C-(Y-SiR85")3 structure at an end; and the compound represented by formula (D1) has a -C-(Y-SiR85 3)2 (specifically, -C-(Y-SiR85 3)2R83) or -C-(Y-SiR85)3 structure, further preferably a -C-(Y-SiR85)3 structure at an end. Such a structure can be at an end, thereby allowing the curable composition of the present invention to contribute to formation of a cured product having higher durability (for example, friction durability). (Other component) [0298] The curable composition of the present invention may further include other component. Such other component is not limited, and may include, for example, a (nonreactive) fluoropolyether compound which can be understood as a fluorine-containing oil, preferably a perfluoro(poly)ether compound (hereinafter, referred to as "fluorine-containing oil"), a stabilizing material (dehydrating agent, molecular sieve, magnesium sulfate or methyl o-formate), a viscosity modifier, a filler, a fluorescent agent, a storage stabilizer, a filling agent, a colorant, a heat resistance improver, a cold resistance improver, a rust inhibitor, an adhesiveness improver, and/or a liquid strengthening agent. [0299] The fluorine-containing oil is not limited, and examples thereof include a compound (perfluoro(poly)ether compound) represented by the following general formula (III) : Rf5-(OC4F8)a'-(OC3F6)b'-(OC2F4)c'-(OCF2)d'-Rf6 ... (III) wherein Rf5 represents an alkyl group having 1 to 16 carbon atoms optionally substituted with one or more fluorine atoms (preferably C1-16 perfluoroalkyl group), Rf6 represents an alkyl group having 1 to 16 carbon atoms optionally substituted with one or more fluorine atoms (preferably C1-16 perfluoroalkyl group), a fluorine atom or a hydrogen atom, and Rf5 and Rf6 are more preferably, each independently, a C1-3 perfluoroalkyl group; and a', b', c' and d' represent the respective four numbers of repeating units in perfluoro(poly)ether constituting a main backbone of the polymer and are mutually independently an integer of 0 or more and 300 or less, the sum of a', b', c' and d' is at least 1, preferably 1 to 300, more preferably 20 to 300, the occurrence order of the respective repeating units in parentheses with the subscript a', b', c' or d' is not limited in the formula, and, among such repeating units, -(OC4F8)- may be any of - (OCF2CF2CF2CF2)-,-(OCF(CF3)CF2CF2)-, -(OCF2CF(CF3)CF2)-, -(OCF2CF2CF(CF3))-,-(OC(CF3)2CF2)-, -(OCF2C(CF3) 2)-, -(OCF(CF3)CF(CF3))-,-(OCF(C2F5)CF2)- and -(OCF2CF(C2F5))-, and is preferably-(OCF2CF2CF2CF2)-, and -(OC3F6)- may be any of - (OCF2CF2CF2)-, -(OCF(CF3)CF2)- and -(OCF2CF(CF3))-, and is preferably-(OCF2CF2CF2)-, and, for example, -(OC2F4)- may be any of-(OCF2CF2)- and -(OCF(CF3))-, and is preferably -(OCF2CF2)-. [0300] Examples of the perfluoro(poly)ether compound represented by general formula (III) include a compound represented by any of the following general formulae (IIIa) and (IIIb) (which may be adopted singly or as a mixture of two or more kinds thereof). Rf5-(OCF2CF2CF2)b"-Rf6 ... (IIIa) Rf5-(OCF2CF2CF2CF2)a"-(OCF2CF2CF2)b"-(OCF2CF2)c"-(0CF2)d"-Rf6 ... (IIIb) [0301] In such formulae, Rf5 and Rf6 are as described above; in formula (IIIa), b" is an integer of 1 or more and 100 or less; in formula (IIIb), a" and b" are each independently an integer of 1 or more and 30 or less, and c" and d" are each independently an integer of 1 or more and 300 or less, and the occurrence order of the respective repeating units in parentheses with subscript a", b", c", d" is not limited in the formulae. [0302] The fluorine-containing oil may have a number average molecular weight of 1,000 to 30,000. In particular, the number average molecular weight of the compound represented by formula (IIIa) is preferably 2,000 to 8,000. In one embodiment, the number average molecular weight of the compound represented by formula (IIIb) is 3,000 to 8,000. In another embodiment, the number average molecular weight of the compound represented by formula (IIIb) is 8,000 to 30,000. [0303] The curable composition can include, for example, 0 to 500 parts by mass, preferably 0 to 100 parts by mass, more preferably 1 to 50 parts by mass, further preferably 1 to 5 parts by mass of the fluorine-containing oil based on 100 parts by mass of the fluorine-containing silane compound (more specifically, PFPE-containing silane compound (A)). [0304] The fluorine-containing oil may be a compound represented by general formula Rf'-F, wherein Rf1 is C5-16 perfluoroalkyl group, from another viewpoint. The fluorine-containing oil may be a chlorotrifluoroethylene oligomer. The compound represented by Rf'-F and the chlorotrifluoroethylene oligomer are preferable in that high affinity with the perfluoro(poly)ether group-containing silane compound where Rf is a C1-16 perfluoroalkyl group is obtained. [0305] The curable composition of the present invention can include the fluorine-containing oil to thereby allow a more flexible cured product to be formed. [0306] In one embodiment, the average molecular weight of the fluorine-containing oil may be higher than the average molecular weight of the fluorine-containing silane compound (for example, a compound represented by formula (A), (B), (C) or (D)). Such an average molecular weight can be set, thereby allowing a cured product formed by using the curable composition of the present invention to achieve more excellent friction durability and surface lubricity. [0307] In one embodiment, for example, the average molecular weight of the fluorine-containing oil may be lower than the average molecular weight of the fluorine-containing silane compound (for example, a compound represented by formula (A), (B), (C) or (D)). Such an average molecular weight can be set, thereby allowing the curable composition of the present invention to not only be inhibited from being reduced in transparency of a cured product formed by using the curable composition, but also lead to formation of a cured product having high friction durability and high surface lubricity. [0308] Examples of the storage stabilizer can include methyltrimethoxysilane, methyltripropenoxysilane, vinyltributanoximesilane and methyltriacetoxysilane. [0309] Examples of the filling agent can include fibrous filling agents such as asbestos, glass fiber and an organic fiber. [0310] Examples of the colorant can include a pigment and a dye. [0311] Examples of the heat resistance improver can include colcothar and cerium oxide. [0312] Examples of the adhesiveness improver can include β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane and γ-isocyanatopropyltriethoxysilane. [0313] Examples of the liquid strengthening agent can include reticular polysiloxane having a triorganosiloxy unit and a SiO2 unit. [0314] An adhesion promoter such as carboxylic anhydride or pyromellitic acid tetraallyl ester can be further added to the curable composition of the present invention. [0315] For example, such a curable composition may be configured as a one-liquid type composition or may be configured as a two-liquid type composition where the two liquids are mixed in use, depending on the application. (Application) [0316] A cured product of the curable composition of the present invention can be used in, for example, a potting material or a sealing material. A cured product of the curable composition of the present invention can be used by, for example, filling any void (for example, a bonding section of a housing and a printed board, or a space between a metal terminal section and a mold resin subjected to resin-molding) of an electronic member with the cured product, and drying the resultant after such filling. [0317] In order that a cured product (for example, a potting material or a sealing material) having higher abrasion resistance is formed, an object to be treated is preferably washed with acetone, hydrofluoroether or the like and thereafter dried for removal of an oily content on the wall of any void, before the treatment with the curable composition of the present invention. The object can be further subjected to a pre-treatment with UV ozone, oxygen plasma or the like, in addition to the washing, thereby allowing abrasion resistance of the cured product to be more enhanced. [0318] A primer treatment can be, if necessary, applied onto, for example, the wall of any void before the treatment with the curable composition of the present invention, thereby enhancing adhesiveness of a potting material formed from the curable composition and more enhancing abrasion resistance. For example, the primer treatment may be performed in the same conditions as those of a primer treatment with a silane coupling agent, according to an ordinary method. [0319] Herein, various primers can also be used in combination in the case where the cured product obtained from the curable composition of the present invention is allowed to adhere to various base materials. [0320] The temperature in the treatment is not limited, and the treatment may be usually performed at room temperature. The treatment time is also not limited, and can be, for example, 5 minutes to 1 hour. [0321] In one embodiment, the curable composition can be cured at room temperature. The curable composition is particularly useful as a composition for formation of a potting material. [0322] In one embodiment, the curable composition of the present invention, when used, may be further diluted with a solvent and thus used, depending on the application and the intended use. Any of the fluorine-based solvents exemplified above can be used as the solvent for use in the dilution. For example, the composition may be used, with being dissolved in a solvent such as 1,3-bis(trifluoromethyl)benzene, Fluorinert (manufactured by 3M), perfluorobutyl methyl ether or perfluorobutyl ethyl ether so that a desired concentration is achieved. In particular, the solvent is preferably used in the application of thin film coating. [0323] The curable composition of the present invention enables a cured product having favorable adhesiveness to a metal or a plastic base material to be formed, and thus can be useful particularly as an adhesive to be applied to peripherals of electrical and electronic components and peripherals of in-car members. The curable composition of the present invention has a favorable elastic modulus particularly even at a low temperature, and thus can be usefully used in, for example, an automobile member (for example, a sealing material, specifically, a gasket), particularly an automobile member usable in a cool region (for example, -50°C or less). [0324] A cured product of the curable composition of the present invention is favorable in chemical resistance, acid resistance and base resistance. Such a cured product of the curable composition of the present invention can also be used in a chemical plant, a semiconductor manufacturing equipment, or the like. [0325] Such a cured product of the curable composition of the present invention can be favorable in transparency. Such a cured product can be particularly used in a member which is demanded to have transparency, for example, an optical material such as a lens, a material for a display, or a material for lighting. Examples [0326] The present invention is more specifically described with reference to the following Examples, but is not intended to be limited to such Examples. The occurrence order of repeating units constituting perfluoropolyether is not limited in the present Examples. [0327] Fluorine-containing silane compounds and cross-linking agents used in Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-4 are as follows. Fluorine-containing silane compound [0328] Compound 1: (C2H5O)3SiCH2CH2CH2NHCOCF2(OC2F4)e-(OCF2)f-CF2CONHCH2CH2CH2Si(OC2H5)3 wherein e = 48 and f = 37 Compound 2: (C2H5O)3SiCH2CH2CH2NHCOCF2(OCF2CF(CF3))mOCF2CF2O(CF(CF3)CF2O)n -CF2CONHCH2CH2CH2Si(OC2H5)3 wherein m + n = 54 Cross-linking agentTetraethoxysilane (TEOS)(Example 1-1) [0329] Compound 1 as a fluorine-containing silane compound, tetraethoxysilane as a cross-linking agent, and teroraisopropaxy titanium as a curing catalyst were weighed in a glass vessel for mixing in amounts of 100 parts by weight, 5 parts by weight, and 0.1 parts by weight, respectively, and stirred with a magnetic stirrer, to prepare a curable composition. (Example 1-2) [0330] A curable composition was obtained in the same manner as in Example 1-1 except that the amount of the catalyst added was any amount described in Table 1. (Comparative Examples 1-1 and 1-2) [0331] Each curable composition was obtained in the same manner as in Example 1-1 except that Ti(OC4H9)4 was used as the catalyst and the amount of the catalyst added was each amount described in Table 1. (Examples 1-3 and 1-4) [0332] Each curable composition was obtained in the same manner as in Example 1-1 except that compound 2 was used as the fluorine-containing silane compound, Zr(OC3H7)4 was used as the catalyst and the amount of the catalyst added was each amount described in Table 1. (Comparative Example 1-3) [0333] A curable composition was obtained in the same manner as in Example 1-3 except that Zr(OC4H9)4 was used as the catalyst and the amount of the catalyst added was any amount described in Table 1. (Comparative Example 1-4) [0334] A curable composition was obtained in the same manner as in Example 1-3 except that Ti(OC3H7)2(C6H9O3)2 was used as the catalyst and the amount of the catalyst added was any amount described in Table 1. (Measurement method of haze value) [0335] Each of the curable compositions obtained in Examples and Comparative Examples was left to still stand under an atmosphere of 25°C and a humidity of 65% for 24 hours, thereby providing a cured product. [0336] The haze value of the resulting cured product was measured with Haze-gard II manufactured by Toyo Seiki Seisaku-sho, Ltd., according to ASTM D1003. The results are shown in Table 1. [0337] Each unit "%" of the amounts of the cross-linking agent and the catalyst added, in Table 1, means a ratio (% by mass) to the mass of the fluorine-containing silane compound. [Table 1] Fluorine-containing silane compound Cross-linking agent Catalyst Haze value Type Amount added Type Amount added Example 1-1 Compound 1 TEOS 5.0% Ti-(OC3H7)4 0.10% 0.25 Example 1-2 Compound 1 TEOS 5.0% Ti-(OC3H7)4 0.50% 0.35 Comparative Example 1-1 Compound 1 TEOS 5.0% Ti-(OC4H9)4 0.10% 1.2 Comparative Example 1-2 Compound 1 TEOS 5.0% Ti-(OC4H9)4 0.50% 1.9 Example 1-3 Compound 2 TEOS 5.0% Zr-(OC3H7)4 0.10% 0.23 Example 1-4 Compound 2 TEOS 5.0% Zr-(OC3H7)4 0.50% 0.29 Comparative Example 1-3 Compound 2 TEOS 5.0% Zr-(OC4H9)4 0.10% 1.5 Comparative Example 1-4 Compound 2 TEOS 5.0% Ti(OC3H7)2(C6H9O3)2 0.10% 3.2 (Example 2-1) [0338] A curable composition was prepared which included the following PFPE-containing silane compound, cross-linking agent, catalyst and solvent and which had a solid concentration of 10% by mass. Hereinafter, the solid concentration refers to a mass ratio of the PFPE-containing silane compound, the cross-linking agent and the catalyst based on 100 parts by mass of the curable composition. [0339] PFPE-containing silane compound: (C2H5O)3SiCH2CH2CH2NHCOCF2(OC2F4)e-(OCF2)f-CF2CONHCH2CH2CH2Si(OC2H5)3, wherein e = 40 and f = 58Cross-linking agent: tetraethoxysilane (TEOS) (10 parts by mass based on 100 parts by mass of PFPE-containing silane compound)Catalyst: tetraisopropyl titanate (0.09 parts by mass based on 100 parts by mass of PFPE-containing silane compound)Solvent: Novec HFE7200 (Examples 2-2 to 2-4) [0340] Each curable composition was prepared in the same manner as in Example 2-1 except that the solid concentration was each concentration described in Table 2. [0341] A glass plate was spray-coated with each of the curable compositions obtained in Examples 2-1 to 2-4. Thereafter, the resultant was left to still stand under an atmosphere of 25°C and a humidity of 65% for 24 hours, thereby forming a cured product. [0342] The thickness of the resulting cured product was measured with a laser microscope (Model No.: VK9710, manufactured by Keyence Corporation). The results are shown in Table 2. Respective numbers in "Thickness" in Table 2 here represent the minimum value and the maximum value measured. The description "Uniform" in Table 2 represents a state where a continuous film was formed without any region not coated, like a pinhole. Specifically, an image obtained by the laser microscope was visually confirmed, and any portion where a glass surface was exposed was determined as having a pinhole. (Comparative Example 2-1) [0343] A composition was prepared which included the following compound having PFPE and the following solvent and which had a solid concentration of 80% by mass. Compound having PFPE: CF3(OC3F6)eCF2(CH2CH(Si(OCH3)3))3Hwherein e = 24Solvent: Novec HFE7200 [0344] A cured product was formed from the composition obtained in Comparative Example 2, according to the same operation as in the compositions obtained in Examples. The cured product obtained from the composition of Comparative Example 2 was not in the form of gel, and a film formed was not uniform. [Table 2] Solid concentration (parts by mass) Thickness (µm) State of film Example 2-1 10 8- 15 Uniform Example 2-2 30 21-33 Uniform Example 2-3 50 30- 43 Uniform Example 2-4 80 45-102 Uniform [0345] A continuous uniform film can be formed from the curable composition of the present invention as shown in Examples 2-1 to 2-4. Industrial Applicability [0346] The present invention can be suitably utilized for forming a fluorine-containing sealing material for embedding any void (for example, a void at a display edge) of a display or between electronic members such as a printed board in electronic equipment.
权利要求:
Claims (10) [0001] A curable composition comprising: a fluorine-containing silane compound having two or more Si atoms each bonding to at least one group selected from the group consisting of a hydroxyl group and a hydrolyzable group; an organosilicon compound having at least two -ORg3(S) each bonding to a Si atom, wherein each Rg3, at each occurrence, is independently a hydrogen atom or a monovalent organic group; and a metal-based catalyst represented by M(-O-Rh)η, wherein: M represents a metal atom; each Rh, at each occurrence, is independently a hydrocarbon group having 1 to 3 carbon atoms; and η is the coordination number of M. [0002] The curable composition according to claim 1, wherein M is at least one selected from the group consisting of titanium, zirconium and tin. [0003] The curable composition according to claim 1 or 2, wherein M is titanium or zirconium. [0004] The curable composition according to any one of claims 1 to 3, wherein the metal-based catalyst is at least one selected from the group consisting of tetrapropyl titanate and tetrapropyl zirconate. [0005] The curable composition according to any one of claims 1 to 4, comprising 0.05 to 5.0 parts by mass of the metal-based catalyst based on 100 parts by mass of the fluorine-containing silane compound. [0006] The curable composition according to any one of claims 1 to 5, wherein the fluorine-containing silane compound is a perfluoropolyether group-containing silane compound. [0007] The curable composition according to any one of claims 1 to 6, wherein the the fluorine-containing silane compound is at least one perfluoropolyether group-containing silane compound represented by formula (A), (B) , (C) or (D) : [0008] The curable composition according to claim 7, wherein X10 is a fluorine atom. [0009] The curable composition according to any one of claims 1 to 8, wherein such a Si atom bonding to at least one group selected from the group consisting of a hydroxyl group and a hydrolyzable group is present at each of both ends of a molecular backbone of the fluorine-containing silane compound, in the fluorine-containing silane compound. [0010] The curable composition according to any one of claims 1 to 9, wherein the organosilicon compound comprises any organosilicon compound represented by the following formulae (E-1) to (E-5): (Rg3-O)ε2-Si-Rg4 4-ε2 ... (E3)wherein: each Rg1, at each occurrence, is independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms; each Rg2, at each occurrence, is independently substituted or unsubstituted and has 1 to 20 carbon atoms; each Rg3, at each occurrence, is independently a hydrogen atom or a monovalent organic group; each Rg4, at each occurrence, is independently a monovalent organic group; Rg6 represents Rg8-Rg7-; each Rg7, at each occurrence, independently represents a single bond, an oxygen atom or a divalent organic group; each Rg8, at each occurrence, is independently an amino group, an epoxy group, a methacrylic group, a vinyl group or a mercapto group; each ε1, at each occurrence, is independently an integer of 1 or more; each ε2, at occurrence, is independently 2 or 3; each ε3, at each occurrence, is independently 2 or 3; ε4 is an integer of 2 or more; ε5 is 1 or 2; and ε6 is an integer of 0 or more.
类似技术:
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同族专利:
公开号 | 公开日 WO2019088117A1|2019-05-09| KR20200055780A|2020-05-21| JPWO2019088117A1|2020-07-02| US20200332123A1|2020-10-22| CN111278918A|2020-06-12|
引用文献:
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法律状态:
2019-05-11| STAA| Information on the status of an ep patent application or granted ep patent|Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE | 2020-08-07| STAA| Information on the status of an ep patent application or granted ep patent|Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE | 2020-08-07| PUAI| Public reference made under article 153(3) epc to a published international application that has entered the european phase|Free format text: ORIGINAL CODE: 0009012 | 2020-09-09| 17P| Request for examination filed|Effective date: 20200422 | 2020-09-09| AK| Designated contracting states|Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR | 2020-09-09| AX| Request for extension of the european patent|Extension state: BA ME | 2021-02-17| DAV| Request for validation of the european patent (deleted)| 2021-02-17| DAX| Request for extension of the european patent (deleted)| 2021-08-25| A4| Supplementary search report drawn up and despatched|Effective date: 20210728 | 2021-08-25| RIC1| Information provided on ipc code assigned before grant|Ipc: C08L 71/00 20060101AFI20210722BHEP Ipc: C08K5/057 20060101ALI20210722BHEP Ipc: C08K5/541520060101ALI20210722BHEP Ipc: C08K5/541920060101ALI20210722BHEP Ipc: C08L 83/06 20060101ALI20210722BHEP Ipc: C08L 83/14 20060101ALI20210722BHEP Ipc: C08G 65/00 20060101ALI20210722BHEP Ipc: C08G 65/336 20060101ALI20210722BHEP |
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