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    • 专利摘要:
    PROCESS FOR THE PRODUCTION OF PAPER, CARDBOARD AND CARDBOARD THAT HAVE HIGH DRY RESISTANCE, NANOCELLULOSE, AND, WATER COMPOSITION The invention relates to a process for the production of paper, cardboard and cardboard that have high dry resistance by adding a composition aqueous product comprising a nanocellulose and at least one polymerized, selected from the group consisting of anionic and water-soluble cationic polymerized materials, dehydration of paper material and drying of paper products.
    公开号:BR112012009141B1
    申请号:R112012009141-7
    申请日:2010-10-14
    公开日:2020-10-13
    发明作者:Anton Esser
    申请人:Basf Se；
    IPC主号:
    专利说明:

    [1] The invention relates to a process for the production of paper, cardboard and cardboard that have high dry resistance by adding an aqueous composition comprising a nanocellulose and at least one polymer selected from the group consisting of anionic polymers and polymers water-soluble cationic, draining the paper load and drying the paper products.
    [2] To increase the strength of the dry paper, a dry drying agent can be applied to the surface of the already dried paper or added to a paper filler before sheet formation. Dry strength agents are commonly used in the form of a 1 to 10%% aqueous solution. If such a dry drying agent solution is applied to the paper surface, considerable amounts of water need to be evaporated in the subsequent drying process.
    [3] As the drying step is very energy intensive and as the capacity of the usual drying apparatus in paper machines in general is not so great that it is possible to operate at the maximum possible speed of production of the paper machine, the production speed of the paper machine needs to be reduced in order for the paper treated with the agent to dry resistance to be dry to a sufficient extent.
    [4] If, on the other hand, the dry strength agent is added to a paper load before sheet formation, the treated paper can be dried only once. E 35 06 832 Al describes a process for the production of paper that has high dry strength, in which a water-soluble cationic polymer is added first and then a water-soluble anionic polymer to the paper load. In the examples, polyethyleneimine, polyvinylamine, polydialyldimethylammonium chloride and cross-linked condensates of adipic acid epichlorohydrin and diethylenetriamine are described as water-soluble cationic polymers. For example, homo or copolymers of C3- to C6-ethylenically unsaturated carboxylic acids are suitable as anionic water-soluble polymers. Copolymers comprise, for example, from 35 to 99% by weight of an ethylenically unsaturated C3- to Cs-carboxylic acid, such as, for example, acrylic acid.
    [5] WO 04/061235 A1 describes a process for the production of paper, in particular paper tissue, which has particularly high wet and / or dry strengths, in which first a water-soluble cationic polymer comprising at least 1.5 meq of primary amino functionality per g of polymer and has a molecular weight of at least 10,000 daltons is added to the paper load. Particularly selected in this case are the homopolymers of N-vinylformamide partially and completely hydrolyzed. After that, a water-soluble anionic polymer comprising anionic and / or aldehydic groups is added. Especially the ability to vary the two-component systems described, in relation to various paper properties, including wet and dry resistance, is emphasized as an advantage of this process.
    [6] WO 06/056381 Al describes a process for the production of paper, cardboard and cardboard that have high dry strength, a separate addition of a water-soluble polymer comprising vinyl amine units and a soluble polymeric anionic compound in water at a paper load, draining the paper load and drying the paper products, the anionic polymeric compound used being at least one water-soluble copolymer that can be obtained by copolymerizing at least one N-vinylcarboxamide of formula (I )
    wherein R1, R2 are H or C1- to Cθ-alkyl, at least one ethylenically unsaturated monomer comprising acid groups and / or the alkali metal, alkaline earth metal or ammonium salts thereof and, optionally, optionally other monomers monoethylenically unsaturated and, optionally, compounds that have at least two ethylenically unsaturated double bonds in the molecule.
    [7] A process for the production of paper that has high dry strength by separately adding a water-soluble cationic polymer and an anionic polymer to a paper filler is described in the previous European patent application with patent application n °. EP 09 150 237.7, wherein the anionic polymer is an aqueous dispersion of a water-insoluble polymer having an acid group content of not more than 10 mol% or an aqueous dispersion of a non-ionic polymer, the dispersion of which has been made anionic. The paper load is then drained and the paper products are dried.
    [8] The previous European patent application with patent application number EP 09 152 163.3 describes a process for the production of paper, cardboard and cardboard that have high dry strength, which is similarly characterized by the addition of a soluble cationic polymer in water and an anionic polymer to a paper load, draining the paper load and drying the paper products. The anionic polymer used there is an aqueous dispersion of at least one anionic latex and at least one degraded starch.
    [9] The purpose of the invention is to provide another process for the production of paper that has high dry strength and as low wet resistance as possible, the dry resistance of paper products being further improved as compared to as possible. the prior art.
    [10] The objective is achieved, according to the invention, by a process for the production of paper, cardboard and cardboard that has high dry resistance by adding an aqueous composition comprising a nanocellulose and at least one polymer, selected from the group consisting of anionic polymers and water-soluble cationic polymers, draining the paper load and drying the paper products.
    [11] In this document, cellulosic nanocellulose is understood to be formed when converted by a stage of the process of the state of the natural fiber that has the usual dimensions of the same (length around 2,000 - 3,000 pm, thickness around 60 pm ) in a way in which the thickness dimension is particularly reduced.
    [12] The preparation of nanocellulose is described in the literature. For example, WO 2007/091942 A1 describes a milling process that can be carried out using enzymes. In addition, processes are known in which cellulose is first dissolved in suitable solvents and then precipitated as nanocellulose in the aqueous medium (for example, described in WO 2003/029329 A2).
    [13] In addition, nanocelluloses are commercially available, for example, products marketed by J. Rettenmeier & Sõhne GmbH & Co. KG under the name of the Arbocel® branded commercial product.
    [14] The nanocelluloses that are used in the process according to the invention according to the invention can be dissolved and used in any suitable solvent, for example, in water, organic solvents or in any desired mixtures thereof. Such solvents may, in addition, comprise other constituents, such as, for example, ionic liquids in any desired amounts.
    [15] Nanocelluloses comprising ionic liquids are prepared, for example, by micronizing celluloses present in ionic liquids and in the form of natural fibers in one of the processes described above. Celluloses in the form of natural fibers that are present in ionic liquids are described, among others, in US 6,824,599 B2. The contents of this US patent are hereby incorporated by reference.
    [16] In particular, in this document, it needs to be understood that nanocellulose means those celluloses whose length dimension is below 1,000 pm, preferably below 500 pm, but above 100 nm. Preferably, the length dimension is therefore from 100 nm to 500 pm, in particular from 100 nm to 100 pm, particularly preferably from 100 nm to 50 pm and especially from 100 nm to 10 pm. The cellulose thickness is, for example, in the range from 50 pm to 3 nm. Preferably, the thickness is from 1 pm to 5 nm. The values for the thickness and length dimensions mentioned in this case are evidently average values; for example, at least 50% of the cellulose fibers are in the mentioned ranges and preferably at least 80% of the cellulose fibers are in the mentioned ranges.
    [17] In another embodiment of the process according to the invention, the preferred nanocellulose is one in which the fiber thickness of at least 80% of the cellulose fibers is from 50 pm to 3 nm, preferably from 1 pm to 5 nm and comprising from 5 ppm to 2% by weight, preferably from 10 ppm to 1% by weight, of ionic liquids.
    [18] The present invention therefore also relates to a nanocellulose such that the fiber thickness of at least 80% of the cellulose fibers is from 50 pm to 3 nm, preferably from 1 pm to 5 nm and which comprises from 5 ppm to 2% by weight, preferably from 10 ppm to 1% by weight, of ionic liquids.
    [19] The length dimension and the thickness of the cellulose fibers can be determined, for example, on the basis of cryochem records. As previously described, the nanocellulose that can be used in the process according to the invention has fiber thicknesses up to 5 nm and length dimensions up to 10 mm. These nanocellulose fibers can also be called fibrils, the smallest superstructure in cellulose-based substances (5-30 nm wide, depending on the variety of the plant; degrees of polymerization of up to 10,000 units of anhydrous glucose). They typically have high elasticity modules of up to several hundred GPa and the strengths of such fibrils are in the GPa range. The high rigidity is a result of the crystal structure, in which the long parallel polysaccharide chains are held together by bridges of hydrogen. The cryoma method is known to the person skilled in the art. Crio-TEM in this context means that the aqueous dispersions of the cellulose are frozen and are measured by means of an electron transmission. Nanocellulose fibers are present in the aqueous medium typically in matted lattices that comprise a large number of fibers. This leads to a gel at the macroscopic level. This gel can be measured rheologically, and the storage module is found to be larger in absolute terms than the loss module. Typically, this gel behavior is present even at concentrations of 0.1 percent by mass of nanocellulose in water.
    [20] In the process according to the invention, aqueous suspensions of nanocelluloses are preferably used which comprise from 0.1 to 25% by weight of nanocellulose, based on the total weight of the aqueous suspension. Preferably, the aqueous suspensions comprise from 1 to 20% by weight, particularly preferably preferably from 1 to 10% by weight and in particular from 1 to 5% by weight of the nanocellulose.
    [21] The aqueous compositions that can be used in the process according to the invention comprise, in addition to nanocellulose, at least one polymer that is selected from the group consisting of anionic and cationic water-soluble polymers.
    [22] In a preferred embodiment of the process according to the invention, the aqueous composition comprises, in addition to nanocellulose, at least one anionic polymer. It is also possible that the aqueous composition comprises at least one water-soluble cationic polymer in addition to nanocellulose and anionic polymer.
    [23] In another embodiment of the process according to the invention, the aqueous composition comprises, in addition to nanocellulose, a water-soluble cationic polymer.
    [24] In the context of this invention, anionic polymers are practically insoluble in water. Thus, for example, at a pH of 7.0 under standard conditions (20 ° C, 1013 mbar), the solubility is not greater than 2.5 g of polymer / liter of water, generally no more than 0.5 g / 1 and preferably not more than 0.1 g / 1. Due to the content of acid groups in the polymer, the dispersions are anionic. The water-insoluble polymer has, for example, an acid group content of from 0.1 to 10 mol%, generally from 0.5 to 9 mol% and preferably from 0.5 to 6 mol%, in particular from 2 to 6 mol%. The content of acid groups in the anionic polymer in general is from 2 to 4 mol%.
    [25] The acidic groups of the anionic polymer are selected, for example, from the groups carboxyl, sulfo and phosphonic acids. Carboxyl groups are particularly preferred in this case.
    [26] Anionic polymers comprise, for example, (a) at least one monomer of the group consisting of C1- to C02-alkyl acrylates, C1- to Czo-alkyl methacrylates, vinyl esters of saturated carboxylic acids that comprise up to 20 carbon atoms, vinilaromatics that have up to 20 carbon atoms, ethylenically unsaturated nitriles, vinyl ethers of saturated monohydric alcohols that comprise 1 to 10 carbon atoms, vinyl halides and aliphatic hydrocarbons that have 2 to 8 carbon atoms carbon and one or two double bonds, (b) at least one anionic monomer of the group consisting of ethylenically unsaturated C3- to Cg-carboxylic acids, vinylsulfonic acid, acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid, vinylphosphonic acid and salts of (c) optionally at least one monomer of the group consisting of C1- to Cio-hydroxyalkyl acrylates, Ci- to Cio-hydroxyalkyl methacrylates, acrylamide, methacrylamide, NC i- a C2o-alkylacrylamides and N-Ci- a C2o-alkylmethacrylamides and, (d) optionally at least one monomer having at least two ethylenically unsaturated double bonds in the molecule incorporated in the form of polymerized units.
    [27] Anionic polymers comprise, for example, at least 40 mol%, preferably at least 60 mol% and in particular at least 80 mol% of at least one monomer of group (a) incorporated as units polymerized. These monomers are practically insoluble in water or provide water insoluble polymers in a homopolymerization carried out with them.
    [28] Anionic polymers preferably comprise, as a monomer of group (a), mixtures of (i) a C1- to C2o-alkyl acrylate and / or a Ci- to C2o-alkyl methacrylate and (ii) styrene , α-methylstyrene, p-methylstyrene, α-butylstyrene, 4-n-butylstyrene, butadiene and / or isoprene in a weight ratio of from 10: 90 to 90: 10 incorporated in the form of polymerized units.
    [29] Examples of individual monomers in group (a) of anionic polymers are monohydric, saturated C1- to C2o-alcohol alcohols or methacrylates such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, acrylate of n-propyl, n-propyl methacrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate , n-pentyl acrylate, n-pentyl methacrylate, n-hexyl acrylate, n-hexyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, acrylate of n-octyl, n-octyl methacrylate, n-decyl acrylate, n-decyl methacrylate, 2-propylheptyl acrylate, 2-propylheptyl methacrylate, dodecyl acrylate, dodecyl methacrylate, lauryl acrylate , lauryl methacrylate, palmitile acrylate, palmitile methacrylate, stearyl acrylate in stearyl ethacrylate. Among these monomers, acrylic acid esters and methacrylic acrylic with saturated monohydric C1- to C1- alcohols are preferably used. Mixtures of these monomers are also used in the preparation of anionic polymers, for example, mixtures of n-butyl acrylate and ethyl acrylate or mixtures of n-butyl acrylate and at least one propyl acrylate.
    [30] Other monomers in group (a) of anionic polymers are: vinyl esters of saturated carboxylic acids having 1 to 20 carbon atoms, for example, vinyl laurate, vinyl stearate, vinyl propionate, vinyl versatate and vinyl acetate, vinyl-aromatic compounds such as styrene, a-methylstyrene, p-methylstyrene, a-butylstyrene, 4-n-butylstyrene and 4-n-decylstyrene, ethylenically unsaturated nitriles, such as acrylonitrile and methacrylonitrile, alcohol ethers saturated materials comprising 1 to 10 carbon atoms, preferably vinyl ethers of saturated alcohols comprising 1 to 4 carbon atoms, such as vinyl methyl ether, vinyl ethyl ether, vinyl-n-propyl ether, vinyl isopropyl ether, vinyl- n-butyl ether or vinyl isobutyl ether, vinyl halides, such as ethylenically unsaturated compounds substituted by chlorine, fluorine or bromine, preferably vinyl chloride and vinylidene chloride and aliphatic hydrocarbons one or two double olefinic bonds and 2 to 8 carbon atoms, such as ethylene, propylene, butadiene, isoprene and chloroprene.
    [31] The preferred group (a) monomers are C 1 -C 2 -alkyl (meth) acrylates and mixtures of aromatic vinyl (meth) acrylates, in particular styrene and / or hydrocarbons that have two double bonds, in in particular, butadiene or mixtures of such aromatic vinyl hydrocarbons, in particular styrene. The monomers of the group (a) of the particularly preferred anionic polymers are n-butyl acrylate, styrene and acrylonitrile, which in each case can be used alone or as a mixture. In the case of monomer mixtures, the weight ratio of alkyl acrylates or alkyl methacrylates to aromatic vinyls and / or hydrocarbons that have two double bonds, such as butadiene, will be, for example, from 10:90 to 90 : 10, preferably from 20:80 to 80:20.
    [32] Examples of anionic monomers of group (b) of anionic polymers are ethylenically unsaturated C3- to Cs-carboxylic acids, such as, for example, acrylic acid, methacrylic acid, dimethacrylic acid, ethacrylic acid, maleic acid, fumaric acid, itaconic acid, mesaconic acid, citraconic acid, methylene malonic acid, allyl acetic acid, vinyl acetic acid and crotonic acid. Other suitable monomers of group (b) are monomers comprising sulfo groups, such as vinylsulfonic acid, acrylamido-2-methylpropanesulfonic acid and styrenesulfonic acid and vinylphosphonic acid. The monomers of this group can be used alone or as a mixture with each other, in partially or completely neutralized form, in copolymerization. For example, alkali metal or alkaline earth metal bases, ammonia, amines and / or alkanolamines are used for neutralization. Examples of these are sodium hydroxide solution, potassium hydroxide solution, sodium carbonate, potassium carbonate, sodium bicarbonate, magnesium oxide, calcium hydroxide, calcium oxide, triethanolamine, ethanolamine, morpholine, diethylenetriamine or tetraethylenopentamine.
    [33] The water-insoluble anionic polymers optionally comprise at least one monomer of the group consisting of C1- to Ciohydroxyalkyl acrylates, Cyto-hydroxyalkyl methacrylates, acrylamide, methacrylamide, N-C1- to C2o-alkylacrylamides and N-C1- to C20-alkylmethacrylamides like other monomers (c). If these monomers are used to modify anionic polymers, acrylamide or methacrylamide is preferably used. The amounts of monomers (c) incorporated in the form of units polymerized to the anionic polymer are up to, for example, 20% by mol, preferably up to 10% by mol and, if these monomers are used in polymerization, they are in the range from 1 to 5 mol%.
    [34] In addition, anionic polymers can optionally comprise monomers of group (d). Suitable monomers in group (d) are compounds that have at least two ethylenically unsaturated double bonds in the molecule. Such compounds are also called cross-linking agents. They comprise, for example, from 2 to 6, preferably from 2 to 4 and generally 2 or 3 double bonds capable of free radical polymerization in the molecule. The double bonds can be, for example, the following groups: acrylate, methacrylate, vinyl ether, vinyl ester, allyl ether and allyl ester. Examples of crosslinking agents are 1,2-ethanediol di (meth) acrylate (here and in the following text, the notation ".. (meth) acrylate" or "(meth) acrylic acid" means both "... acrylate" such as "... methacrylate" or acrylic acid as well as methacrylic acid), 1,3-propanediol di (meth) acrylate, 1,2-propanediol di (meth) acrylate, 1, 4- di (meth) acrylate butanediol, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylol propanetriol di (meth) acrylate, pentaerythritol tetra di (meth) acrylate, 1, 4-butanedioldivinyl ether, 1, 6- hexanedioldivinyl ether, 1,4-cyclohexanedioldivinyl ether, divinylbenzene, allyl acrylate, allyl methacrylate, methyl acrylate, methyl methacrylate, but-3-en-2-yl acrylate, (but) 3-en-2-yl acrylate 2-en-l-yl, 3-methylbut-2-en-l-yl (meth) acrylate, (meth) acrylic acid esters with geraniol, citronalal, cinnamic alcohol, glyceryl mono- or diallyl ether, trimethylolpropane mono- on-dialyl ether, ethylene g monoallyl ether, diethylene glycol monoallyl ether, propylene glycol monoallyl ether, dipropylene glycol monoallyl ether, 1,3-propanediolmonoalyl ether, 1,4-butanediolmonoalyl ether and also dialyl itaconate. Allyl acrylate, divinylbenzene, diacrylate 1, 4-butanediol and 1,6-hexanediol diacrylate are preferred. If a crosslinking agent is used to modify anionic polymers, the amounts incorporated in the form of polymerized units are up to 2 mol%. They are, for example, in the range of from 0.001 to 2, preferably from 0.01 to 1.0, mol%.
    [35] The water-insoluble anionic polymers preferably comprise, as monomers (a), mixtures of 20 - 50 mol% of styrene and 30 - 80 mol% of at least one alkyl methacrylate and / or at least one acrylate of alkyl incorporated in the form of polymerized units. They can optionally also comprise up to 30 mol% of methacrylonitrile or acrylonitrile incorporated in the form of polymerized units. Such polymers can optionally also be modified by the amounts of methacrylamide and / or acrylamide that are mentioned above under the monomers of group (c).
    [36] Preferred anionic polymers comprise (a) at least 60 mol% of at least one monomer in the group consisting of C1- to C20-alkyl acrylate, C1- to C2-alkyl methacrylate, vinyl acetate , vinyl propionate, styrene, a-methylstyrene, p-methylstyrene, a-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene, acrylonitrile, methacrylonitrile, butadiene and isoprene and (b) from 0.5 to 9% in mol of at least one anionic monomer of the group consisting of ethylenically unsaturated C3- to Cs-carboxylic acids incorporated in the form of polymerized units.
    [37] Anionic polymers comprising at least 80 mol% of at least one monomer of the group (a) incorporated in the form of polymerized units are particularly preferred. They generally comprise, as a monomer of group (a), mixtures of (i) a C1- to C20-alkyl acrylate and / or a C1- to C20-alkyl methacrylate and (ii) styrene, a-methylstyrene , p-methylstyrene, a-butylstyrene, 4-n-butylstyrene, butadiene and / or isoprene in the weight ratio from 10: 90 to 90: 10 incorporated in the form of polymerized units.
    [38] The preparation of anionic polymers is carried out as a rule by emulsion polymerization emulsion polymerization. Anionic polymers are therefore emulsion polymers. The preparation of aqueous polymer dispersions by the free radical emulsion polymerization process is known per se (cf. Houben-Weil, Methoden der organischen Chemie, volume XIV, Makromolekulare Stoffe, Georg Thieme Verlag, Stuttgart 1961, pages 133 and following) .
    [39] In emulsion polymerization for the preparation of anionic polymers, ionic and / or non-ionic emulsifiers and / or protective colloids or stabilizers are used as surfactant compounds. The active surfactant is usually used in amounts of from 0.1 to 10% by weight, in particular from 0.2 to 3% by weight, based on the monomers to be polymerized.
    [40] Usual emulsifiers are, for example, ammonium or alkali metal salts of higher fatty alcohol sulphates, such as sodium n-lauryl sulphate, fatty alcohol phosphates, ethoxylated Cg- to C1-6 alkylphenols which have a degree of ethoxylation from 3 to 30 and Cg- to C25 alcohol ethoxylates with an ethoxylation degree from 5 to 50. Mixtures of nonionic and ionic emulsifiers are also conceivable. Alkylphenols and / or fatty and ethoxylated and / or propoxylated alcohols containing phosphate or sulfate groups are also suitable. Other suitable emulsifiers are mentioned in Houben-Weil, Methoden der organischen Chemie, volume XIV, Makromolekulare Stoffe, Georg Thieme Verlag, Stuttgart, 1961, pages 192 to 209.
    [41] Primers for water-soluble emulsion polymerization for the preparation of anionic polymers are, for example, ammonium and alkali metal salts of peroxodisulfuric acid, for example, sodium peroxodisulfate, hydrogen peroxide or organic peroxides, for example example, tert-butyl hydroperoxide.
    [42] So-called reduction-oxidation (redox) initiator systems are also suitable, for example, combinations of peroxides, hydroperoxides or hydrogen peroxide with reducing agents, such as ascorbic acid or sodium bisulfite. These initiator systems can additionally comprise metal ions, such as iron (II) ions.
    [43] The amount of initiators is generally 0.1 to 10% by weight, preferably 0.5 to 5% by weight, based on the monomers to be polymerized. It is also possible to use a large number of different initiators in emulsion polymerization.
    [44] In emulsion polymerization, it is optionally possible to use regulators, for example, in amounts from 0 to 3 parts by weight, based on 100 parts by weight of the monomers to be polymerized. As a result, the molar mass of the resulting polymers is reduced. Suitable regulators are, for example, compounds that have a thiol group, such as tert-butyl mercaptan, thioglycolic acid, ethyl acrylate, mercaptoethanol, mercaptopropyltrimethoxysilane or tert-dodecyl mercaptan or regulators without a thiol group, in particular, for example, terpinolene.
    [45] Emulsion polymerization for the preparation of anionic polymers is carried out as a rule from 30 to 130 ° C, preferably from 50 to 100 ° C. The polymerization medium can consist of both water and mixtures of water and liquids miscible with it, such as methanol. Preferably, only water is used. Emulsion polymerization can be carried out either as a batch process or as a feed process, which includes the gradient procedure step. The feeding process is preferred in which part of the polymerization batch is removed initially, heated to the polymerization temperature and partially polymerized and then the remainder of the batch polymerization is fed to the polymerization zone continuously, in stages or with superposition of a concentration gradient while polymerization is maintained, usually by a large number of spatially separated feeds, one or more of which comprise the monomers in pure or emulsified form. In polymerization, a polymer seed can also be removed initially, for example, to better adjust the particle size.
    [46] The manner in which the initiator is added to the polymerization reactor during aqueous polymerization free radical emulsion polymerization is known to the person skilled in the art. This can be completely removed initially in the container for polymerization or used continuously or in stages at the rate of consumption during a free radical emulsion polymerization. Specifically, this depends on the chemical nature of the initiator system as well as the temperature of the polymerization. Preferably, a portion is initially removed and the rest is fed to the polymerization zone at the rate of consumption.
    [47] To remove residual monomers, at least one initiator is added again, usually also after the end of the polymerization in real emulsion, that is, after a conversion of the monomers of at least 95% and the reaction mixture is heated for a certain period of time until the polymerization temperature or at a temperature above it.
    [48] Individual components can be added to the reactor in the feeding process as above, from the side or below the bottom of the reactor.
    [49] After (co) polymerization, the acid groups present in the anionic polymer can also be at least partially or completely neutralized. This can be done, for example, with oxides, hydroxides, carbonates or bicarbonates of alkali metals or alkaline earth metals, preferably with hydroxides, with which any desired indicator ion or a large number of them can be associated, for example , Li +, Na +, K +, Cs +, Mg2 +, Ca2 + or Ba2 +. In addition, ammonia or amines are suitable for neutralization. Aqueous solutions of ammonium hydroxide, sodium hydroxide or potassium hydroxide are preferred.
    [50] In emulsion polymerization, aqueous dispersions of the anionic polymer are obtained as a rule with solids contents from 15 to 75% by weight, preferably from 40 to 75% by weight. The Mw molar mass of anionic polymers is, for example, in the range of 100,000 to 1 million daltons. If the polymers have a gel phase, it is not possible to determine the molar mass directly. The molar masses are then above the range mentioned above.
    [51] The glass transition temperature Tg of anionic polymers is, for example, in the range of - 30 to 100 ° C, preferably in the range of - 5 to 70 ° C and particularly preferably in the range of from 0 to 40 ° C (measured by DSC method according to DIN EN ISO 11357).
    [52] The particle size of the dispersed anionic polymers is preferably in the range from 10 to 1,000 nm, particularly preferably in the range from 50 to 300 nm (measured using a Malvern® Autosizer 2 C).
    [53] The anionic polymer can optionally comprise small amounts of cationic monomer units incorporated in the form of polymerized units, so that amphoteric polymers are present, however the total polymer charge must be anionic. Other suitable anionic polymers are polymer dispersions of nonionic monomers that are emulsified with the help of anionic surfactants or emulsifiers (such compounds have been described before in the case of emulsion polymerization for the preparation of anionic polymers). For this application, surfactants or emulsifiers are used, for example, in amounts from 1 to 15% by weight, based on the total dispersion.
    [54] As described above, in addition to nanocellulose, the aqueous composition can also comprise a water-soluble cationic polymer in addition to or alternatively to the anionic polymer.
    [55] Suitable cationic polymers are all of the water-soluble cationic polymers mentioned in the prior art mentioned above. These are, for example, compounds that contain amino or ammonium groups. Amino groups can be primary, secondary, tertiary or quaternary groups. For polymers, in essence, addition polymers, polyaddition or polycondensate compounds are suitable, and it is possible that the polymers have a linear or branched structure, including hyper-branched or dendritic structures. Graft polymers can also be used. In the present context, cationic polymers are cited as being water-soluble if their solubility in water under standard conditions (20 ° C, 1013 mbar) and pH 7.0 is, for example, at least 10% by weight.
    [56] The Mw molar masses of cationic polymers are, for example, at least 1,000 g / mol. These are, for example, generally in the range of 5,000 to 5 million g / mol. The charge densities of cationic polymers are, for example, from 0.5 to 23 meq / g of polymer, preferably from 3 to 22 meq / g of polymer and in general from 6 to 20 meq / g of polymer .
    [57] Examples of suitable monomers for the preparation of cationic polymers are:
    [58] Esters of mono- and dicarboxylic acids α, β-ethylenically unsaturated with amino alcohols, preferably C2-Ci2-amino alcohols. These will be Ci-Cs-monoalkylated on dialkylated in the amine nitrogen. Suitable components of these esters are, for example, acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, crotonic acid, maleic anhydride, monobutyl maleate and mixtures thereof. Preferably acrylic acid, methacrylic acrylic and mixtures thereof are used. These include, for example, N-methylaminomethyl (meth) acrylate, N-methylaminoethyl (meth) acrylate, N, N-dimethylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl, (meth) acrylate of N, N-diethylaminoethyl, (meth) acrylate of N, N-dimethylaminopropyl, (meth) acrylate of N, N-diethylaminopropyl and (meth) acrylate of N, N-dimethylaminocyclohexyl.
    [59] Quaternization products of the above compounds with C 1 -Cs-alkyl chlorides, C 1 -Cs-dialkyl sulfates, C 1 -C 6 epoxides or benzyl chloride are also suitable.
    [60] In addition, N- [2- (dimethylamino) ethyl] acrylamide, N- [2-dimethylamino) ethyl] methacrylamide, N- [3- (dimethylamino) propyl] acrylamide, N- [3- ( dimethylamino) propyl] methacrylamide, N- [4- (dimethylamino) butyl] acrylamide, N- [4- (dimethylamino) butyl] methacrylamide, N- [2- (diethylamino) ethyl] acrylamide, N- [2- ( diethylamino) ethyl] methacrylamide and mixtures thereof are suitable with other monomers.
    [61] Quaternization products of the above compounds with C 1 -C 6 -alkyl chloride, C 1 -C 6 dialkyl sulphate, C-C 6 -epoxides or benzyl chloride are also suitable.
    [62] Suitable monomers are also N-vinylimidazoles, alkylvinylimidazoles, in particular methylvinylimidazoles, such as l-vinyl-2-methylimidazole, 3-vinylimidazole N-oxide, 2- and 4-vinylpyridines, 2- and N-oxides 4-vinylpyridine and betaine derivatives and quaternization products of these monomers.
    [63] Other suitable monomers are alkylamine, dialkyldiallylammonium chlorides, in particular dimethyldiallylammonium chloride and diethyldialylammonium chloride (mnnnnwrns dpxrritok in Wf) 01 / ^ 6500 Al, which comprise
    where R is hydrogen or C1- to C4-alkyl, - [AI-] m is a linear or branched oligoalkyleneimine chain that has m alkyleneimine units, m is an integer in the range from 1 to 20 and the average number m in the oligoalkyleneimine chains it is at least 1.5, Y is the equivalent anion of a mineral acid and n is a number such that 1 <_n <_m.
    [64] Monomers or monomer mixtures in which the average number of m is at least 2.1, generally from 2.1 to 8, in the formula (II) mentioned above are preferred. They can be obtained by reacting an ethylenically unsaturated carboxylic acid with an oligoalkyleneimine, preferably in the form of an oligomer mixture. The resulting product can optionally be converted with a mineral acid HY to the acid addition salt. Such monomers can be polymerized to provide cationic homo- and copolymers in an aqueous medium in the presence of an initiator that initiates free radical polymerization.
    [65] Other suitable cationic monomers are described in WO 2009/043860 Al. These are aminoalkyl vinyl ethers comprising alkyleneimine and formula (III) units
    where [AI-] is a straight or branched oligoalkyleneimine chain that has n alkyleneimine units, n is a number of at least 1 and X is a straight or branched C2- to C-alkylene group, and salts of the monomers (III) with mineral acids or organic acids and quaternization products of monomers (III) with or dialkyl sulfates. These compounds can be obtained by an addition reaction of alkyleneimines with amino-C2- to C0-alkyl vinyl ethers.
    [66] The aforementioned monomers can be polymerized alone to provide water-soluble cationic homopolymers or together with at least one other neutral monomer to provide water-soluble cationic copolymers or with at least one monomer that has acid groups to provide amphoteric copolymers that, in the in case of a molar excess of cationic monomers incorporated in the form of polymerized units, contain a global cationic charge.
    [67] Suitable neutral monomers that are copolymerized with the cationic monomers mentioned above for the preparation of cationic polymers are, for example, esters of mono- and dicarboxylic acids oc, β-ethylenically unsaturated with Ci-Cso-alkanols, C2-C30 - alkanodiols, amides of α, β-ethylenically unsaturated monocarboxylic acids and the N-alkyl and N, N-dialkyl derivatives thereof, vinyl alcohol and allyl esters with saturated Ci-Cso-monocarboxylic acids, vinyl vinyl halides , vinylidene halides, C2-C8-mono-olefins and mixtures thereof.
    [68] Other suitable comonomers are, for example, (meth) methyl acrylate, methyl ethacrylate, (meth) ethyl acrylate, ethyl ethacrylate, (n) butyl acrylate, (meth) isobutyl acrylate, ( met) tert-butyl acrylate, tert-butyl ethacrylate, (meth) n-octyl acrylate, (meth) 1, 1, 3, 3-tetramethylbutyl acrylate, (meth) ethylhexyl acrylate and mixtures thereof .
    [69] Also suitable are acrylamide, substituted acrylamides, methacrylamide, substituted methacrylamides, such as, for example, acrylamide, methacrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide , N- (n-butyl) (meth) acrylamide, tert-butyl (meth) acrylamide, n-octyl (meth) acrylamide, 1, 1, 3, 3-tetramethylbutyl (meth) acrylamide and ethylhexyl (meth) acrylamide and acrylonitrile and methacrylonitrile and mixtures of said monomers.
    [70] Other monomers to modify cationic polymers are 2-hydroxyethyl (meth) acrylate, 2-hydroxyethyl ethacrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (3) 3-acrylate - hydroxybutyl, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, etc. and mixtures thereof.
    [71] Other monomers suitable for copolymerization with the aforementioned cationic monomers are N-vinillactamas and derivatives thereof, which may have, for example, one or more C1- C-alkyl substituents, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl etc. These include, for example, N-vinylpyrrolidone, N-vinylpiperidone, N-vinylcaprolactam, N-vinyl-5-methyl-2-pyrrolidone, N-vinyl-5-ethyl-2-pyrrolidone, N - vinyl-6-methyl- 2-piperidone, N - vinyl-6-ethyl-2-piperidone, N-vinyl-7-methyl-2-caprolactam, N-vinyl-7-ethyl-2-caprolactam etc.
    [72] Comonomers suitable for copolymerization with the aforementioned cationic monomers are furthermore ethylene, propylene, isobutylene, butadiene, styrene, oc-methylstyrene, vinyl chloride, vinylidene chloride, vinyl fluoride, vinyl fluoride and mixtures of themselves.
    [73] Another group of comonomers comprises ethylenically unsaturated compounds that contain a group from which an amino group can be formed in a reaction analogous to a polymer. These include, for example, N-vinylformamide, N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, N-vinyl-N-ethylacetamide, N-vinylpropionamide, N-vinyl-N-methylpropionamide and N-vinylbutyramide and mixtures thereof. Polymers formed from them can, as described in EP 0 438 744 A1, be converted by acidic or basic hydrolysis into polymers comprising vinylamine and amidine units (formulas IV - VII)

    [74] In formulas IV - VII, the substituents R1, R2 are H, C1- to CÔ-alkyl and X- is an equivalent anion of an acid, preferably a mineral acid.
    [75] For example, polyvinylamines, polyvinylmethylamines or polyvinylethylamines are formed during hydrolysis. The monomers of this group can be polymerized in any desired way with the cationic monomers and / or the comonomers mentioned above.
    [76] It also needs to be understood that cationic polymers in the context of the present invention mean amphoteric polymers that contain a global cationic charge. In amphoteric polymers, the content of cationic groups, for example, is at least 5 mol% above the content of anionic groups in the polymer. Such polymers can be obtained, for example, by copolymerization of a cationic monomer, such as N, N-dimethylaminoethylacrylamide, in the form of the free base, in the form partially neutralized with an acid or in the quaternized form, with at least one monomer comprising acid groups, the cationic monomer being used in a molar excess and so that the resulting polymers contain a global cationic charge.
    [77] Amphoteric polymers can also be obtained by copolymerization of (i) at least one N-vinylcarboxamide of formula (I)
    wherein R1, R2 are H or C1- to C-alkyl, (ii) at least one ethylenically unsaturated monocarboxylic acid having 3 to 8 carbon atoms in the molecule and / or the alkali metal, alkaline earth metal salts or ammonium thereof and optionally (iii) other monoethylenically unsaturated monomers and optionally (iv) compounds having at least two ethylenically unsaturated double bonds in the molecule, and subsequent partial or complete elimination of the -CO- R1 groups of the monomers of formula (I ) which are incorporated in the form of polymerized units in the copolymer, with formation of amino groups, the content of cationic groups, such as amino groups, in the copolymer that is at least 5 mol% above the content of acidic groups of the monomers (ii) incorporated in the form of polymerized units. In the hydrolysis of N-vinylcarboxamide polymers, the amidine units are formed in a secondary reaction by reacting vinylamine units with a neighboring vinyl formamide unit. In the following, the mention of vinylamine units in amphoteric copolymers always means the sum of vinylamine and amidine units.
    [78] The amphoteric compounds that can be obtained thus comprise, for example, (ii) optionally, non-hydrolyzed units of formula (I), (I2) vinylamine units and amidine units, the content of amino plus amidine groups in the copolymer being at least 5 mol% above the monomer content comprising acidic groups and incorporated in the form of polymerized units, (iii) units of a monoethylenically unsaturated monomer comprising acidic groups and / or the alkali metal, alkali metal salts - earth or ammonium thereof, (iv)) from 0 to 30 mol% of units of at least another monoethylenically unsaturated monomer and (v)) from 0 to 2 mol% of at least one compound having at least two double ethylenically unsaturated bonds in the molecule.
    [79] Hydrolysis of copolymers can be carried out in the presence of acids or bases or enzymatically. In acid hydrolysis, the vinylamine groups that form the vinylcarboxamide units are present in the form of salt. The hydrolysis of vinylcarboxamide copolymers is described in detail in EP 0 438 744 A1, page 8, line 20 to page 10, line 3. The statements made therein apply accordingly to the preparation of the amphoteric polymers to be used according to the invention. and that have a global cationic charge.
    [80] These polymers have, for example, K values (determined according to H. Fikentscher in aqueous solution at a concentration of 5% sodium chloride at a pH of 7, a polymer concentration of 0.5% in weight and at a temperature of 25 ° C) in the range from 20 to 250, preferably from 50 to 150.
    [81] The preparation of cationic homo- and copolymers can be carried out by solution, precipitation, suspension or emulsion polymerization. Solution polymerization in aqueous media is preferred. Suitable aqueous media are water and mixtures of water and at least one water-miscible solvent, for example, an alcohol, such as methanol, ethanol, n-propanol etc.
    [82] The polymerization temperatures are preferably in the range of from about 30 to 200 ° C, particularly preferably from 40 to 110 ° C. Polymerization is usually carried out under atmospheric pressure but can also occur under reduced pressure or superatmospheric pressure. A suitable pressure range is from 0.1 to 5 bar.
    [83] For the preparation of cationic polymers, monomers can be polymerized with the aid of free radical initiators.
    [84] The free radical initiators for polymerization that can be used are the peroxo and / or azo compounds customary for this purpose, for example, alkali or ammonium metal peroxodisulfate, diacetyl peroxide, dibenzoyl peroxide, succinyl peroxide, di-tert-butyl peroxide, di-tert-butyl perbenzoate, tert-butyl perpivalate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl permaleate, cumila hydroperoxide, diisopropyl peroxydicarbamate, diisopropyl peroxide bis (o-toluyl), didecanyl peroxide, dioctanoyl peroxide, dilauroyl peroxide, tert-butyl perisobutyrate, tert-butyl peracetate, di-tert-amyl peroxide, tert-butyl hydroperoxide, azobisisobutyronitrile, azobisisobutyronitrile, azobisis hydrobromide (2-amidinopropane) or 2-2'-azobis (2-methylbutyronitrile). Mixtures of initiators or initiators of redox systems are also suitable, such as, for example, ascorbic acid / iron (II) sulfate / sodium peroxodisulfate, tert-butyl hydroperoxide / sodium disulfite, tert-butyl hydroperoxide / hydroxymethanesulfinate sodium, J-UCh / CuCI) or iron (II) compounds.
    [85] For the adjustment of the molecular weight, polymerization can be carried out in the presence of at least one regulator. Regulators that can be used are the usual compounds known to the person skilled in the art, such as, for example, sulfur compounds, for example, mercaptoethanol, 2-ethylhexyl thioglycolate or thioglycolic acid, sodium hypophosphite, formic acid or dodecyl mercaptan and tribromochloromethane or other compounds that regulate the molecular weight of the polymers obtained.
    [86] Cationic polymers, such as polyvinylamines and copolymers thereof, can also be prepared by degrading polyacrylamide or Hofmann's polymethacrylamide and copolymers thereof, cf. H. Tanaka, Journal of Polymer Science: Polymer Chemistry edition 17, 1239-1245 (1979) and El Achari, X. Coqueret, A. Lablache-Combier, C. Loucheux, Makromol. Chem., Vol. 194, 1879-1891 (1993).
    [87] All of the cationic polymers mentioned above can be modified by carrying out the polymerization of the cationic monomers and optionally the mixtures of cationic monomer and comonomers in the presence of at least one crosslinking agent. A crosslinking agent is understood to mean those monomers comprising at least two double bonds in the molecule, for example, methylenebisacrylamide, glycol diacrylate, glycol dimethacrylate, glyceryl triacrylate, pentaerythritol trialyl ether, polyalkylene glycols that are at least diesterified with acid. and / or with methacrylic acrylic or polyols such as pentaerythritol, sorbitol or glucose. If at least one crosslinking agent is used in the copolymerization, the amounts used are, for example, up to 2 mol%, for example, from 0.001 to 1 mol%.
    [88] In addition, the cationic polymer can be modified by the subsequent addition of crosslinking agents, that is, by adding compounds that have at least two reactive groups with amino groups, such as, for example, - di- and di- polyglycidyl, - di- and polyhalogen compounds, - compounds that have two or more isocyanate groups, possibly derived from blocked carbonic acid, - compounds that have two or more double bonds that are suitable for a Michael addition, - di - and polyaldehydes, - monoethylenically unsaturated carboxylic acids and their esters and anhydrides.
    [89] Suitable cationic compounds are furthermore polymers that can be produced by polyaddition reactions, such as, in particular, polymers based on aziridines. It is possible to form both homopolymers and graft polymers, which are produced by grafting aziridines onto other polymers. It may also be advantageous in this case to add, during or after polyaddition, that it has at least two groups that can react with aziridines or with the amino groups formed, such as, for example, epichlorohydrin or dihaloalkanes. Crosslinking agent (cf. UllmanrTs Encyclopedia of Industrial Chemistry, VCH, Weinheim, 1992, aziridine chapter).
    [90] Preferred polymers of this type are based on ethyleneimine, for example, ethyleneimine homopolymers which are prepared by polymerization of ethyleneimine or polymers grafted with ethyleneimine, such as polyamidoamines.
    [91] Other suitable cationic polymers are products of the reaction of dialkylamines with epichlorohydrin or with di- or polyfunctional epoxides, such as, for example, products of the reaction of dimethylamine with epichlorohydrin.
    [92] Other suitable cationic polymers are polycondensed, for example, homo- or copolymers of lysine, arginine and histidine. They can be used as homopolymers or as copolymers with other natural or synthetic amino acids or lactams. For example, glycine, alanine, valine, leucine, phenylalanine, tryptophan, proline, asparagine, glutamine, serine, threonine or caprolactam are suitable for copolymerization.
    [93] In addition, condensates of difunctional carboxylic acids with polyfunctional amines such as cationic polymers, polyfunctional amines containing at least two primary amino groups and at least one less reactive, that is, secondary, tertiary or quaternary amino group, can be used. Examples are the polycondensation products of diethylenetriamine or triethylenetetramine with adipic, malonic, glutaric, oxalic or succinic acid.
    [94] Polysaccharides that contain amino groups, such as, for example, chitosan, are also suitable as cationic polymers.
    [95] In addition, all polymers that are described above and contain primary and secondary amino groups can be modified by means of reactive oligoethyleneimines, as described in WO 2009/080613 A1. This patent application describes grafted polymers whose grafting base is selected from the group consisting of polymers that have vinylamine units, polyamines, polyamidoamines and polymers of ethylenically unsaturated acids and that comprise, as side chains, exclusively oligoalkyleneimine side chains. The preparation of grafted polymers having oligoalkyleneimine side chains is carried out by grafting at least one oligoalkyleneimine which comprises a terminal aziridine group on one of the graft bases.
    [96] In a preferred embodiment of the process according to the invention, a polymer is used that has vinylamine units as the water-soluble cationic polymer.
    [97] The present invention also relates to an aqueous composition comprising a nanocellulose and at least one polymer selected from the group consisting of anionic polymers and water-soluble cationic polymers, as can be used in the process according to the invention that is described above.
    [98] The fibers suitable for the production of pulp are all of customary qualities for this purpose, for example, mechanical pulp, bleached and unbleached chemical pulp and paper loads from all annual plants. The mechanical pulp includes, for example, ground wood pulp, thermomechanical pulp (TMP), chemothermomechanical pulp (CTMP), pressure-milled wood, semi-chemical pulp, high-performance chemical pulp and refiner mechanical pulp (RMP). For example, sulphate, sulphite and soda pastes are suitable as a chemical paste. Preferably unbleached mechanical pulp is used, which is also called unbleached chemical pulp, which is also called unbleached Kraft pulp. The annual plants suitable for the production of paper loads are, for example, rice, wheat, sugar cane and kenaf. Pastes are generally produced using waste paper, which is used alone or as a mixture with other fibers or fiber mixtures comprising a primary pulp and recycled coated waste, for example, bleached pine sulfate mixed with recycled coated waste , are used as starting materials.
    [99] The process according to the invention is of special industrial interest for the production of paper and cardboard from waste paper because it substantially increases the strength properties of recycled fibers and is particularly important for improving the strength properties of recycled fibers. graphic arts papers and packaging papers. The papers that can be obtained by the process according to the invention surprisingly have a higher dry resistance than the papers that can be produced by the process of WO 2006/056381 A1.
    [100] The pH of the load suspension is, for example, in the range of 4.5 to 8, generally from 6 to 7.5. For example, an acid, such as sulfuric acid or aluminum sulfate, can be used to adjust the pH.
    [101] In the process according to the invention, the aqueous composition comprising a nanocellulose and at least one polymer is first prepared. It is unimportant if the nanocellulose is initially removed and at least one polymer is added to the nanocellulose or vice versa. If both an anionic polymer and a water-soluble cationic polymer are added, the sequence is similarly unimportant.
    [102] In a preferred embodiment of the process according to the invention, the aqueous suspension of the nanocellulose is first heated, for example, to 60 ° C, preferably to 50 ° C and particularly preferably to a range of from 30 to 50 ° C. Thereafter, an aqueous dispersion of at least one anionic polymer is introduced after measurement. It is also possible, if necessary, to add at least one cationic polymer to this aqueous composition.
    [103] In another preferred embodiment of the process according to the invention, at least one cationic polymer is added to the aqueous composition, at least this cationic polymer is preferably added to an aqueous suspension of the nanocellulose, the suspension of which was heated as described above. Then anionic polymer is optionally added.
    [104] Regardless of the aforementioned modalities, the aqueous composition in the process according to the invention can be added to the high consistency filler (fiber concentration> 15 g / 1, for example, in the range from 25 to 40 g / 1 up to 60 g / 1) or preferably at a low consistency load (fiber concentration <15 g / 1, for example, in the range from 5 to 12 g / 1). The point of addition is preferably before the wires but it can also be between a shear stage and a screen or after that.
    [105] The water-insoluble anionic polymer is used, for example, in an amount of from 0.1 to 10% by weight, preferably from 0.3 to 6% by weight, in particular from 0.5 to 5.5% by weight, based on the dry paper load.
    [106] The cationic polymer used optionally is used, for example, in an amount of from 0.03 to 2.0% by weight, preferably from 0.1 to 0.5% by weight, based on the paper load dry.
    [107] The optionally used weight ratio of water-soluble cationic polymer to water-insoluble anionic polymer is, based on the solids content, for example, from 1: 5 to 1:20 and is preferably in the range of from 1 : 10 to 1:15 and particularly preferably in the range from 1:10 to 1:12.
    [108] In the process according to the invention, process chemicals commonly used in papermaking can be used in customary amounts, for example, retention aid, drainage agent, other agents for dry strength, such as, for example, starch, pigments, fillers, optical brightening agents, defoamers, biocides and dyes for papers.
    [109] The invention is explained in more detail by means of the following non-limiting examples. Examples
    [110] Unless stated otherwise, the percentages given in the examples are in percent by weight.
    [111] The K value of the polymers was determined according to Fikentscher, Cellulose-Chemie, volume 13, 58 - 64 and 71 - 74 (1932) at a temperature of 20 ° C in aqueous solutions of sodium chloride at a concentration 5% by weight, at a pH of 7 and at a polymer concentration of 0.5%. In this context, K = k 1000.
    [112] The cited average particle sizes were determined according to ISO 13321 by diffusing the almost elastic light using a Malvern® Autosizer 2 C in samples with 0.01% concentration by weight.
    [113] The following polymers have been tested in the examples and comparative examples: Cationic polymer A
    [114] This polymer was prepared by hydrolysis of a poly-N-vinylformamide with hydrochloric acid. The degree of hydrolysis of the polymer was 50 mol%, that is, the polymer comprised 50 mol% of N-vinylformamide units and 50 mol% of vinylamine units in saline form. The K value of the water-soluble cationic polymer was 90. Anionic polymer B
    [115] Anionic polymer B was present as anionic acrylate resin that has a solids content of 50% and was obtained by suspension polymerization of 68% by mol of n-butyl acrylate, 14% by mol of styrene, 14 mole% of acrylonitrile and 4 mole% of acrylic acid. The average particle size of the dispersed polymer particles was 192 nm. Anionic polymer C
    [116] The anionic polymer C was present as an anionic acrylate resin that has a solids content of 50% and was obtained by suspension polymerization of 87 mol% of n-butyl acrylate, 5 mol% of styrene, 5 mole% of acrylonitrile and 3 mole% of acrylic acid. The average particle size of the dispersed polymer particles was 184 nm. Nanocellulose
    [117] A rotating disk reactor that was equipped with a cellulose solution feed and four water feed points was used to prepare the nanocellulose. The feed for the cellulose solution was positioned centrally above the disk axis, 1 mm away from the disk surface. The water feeds were positioned at equal distances from each other, in each case 5 cm away from the axis and 1 mm away from the disc surface. The surface of the disk and the jacket of the rotating disk reactor were heated to 95 ° C. The reactor was filled with nitrogen. At a speed of rotation of the disk of 2500 revolutions per minute, cellulose solutions in an ionic liquid (Weyerhãuser cellulose, 1% by weight in l-ethyl-3-methylimidazolium acetate, 50 g / min dose at a pressure of 2 bar nitrogen) that were at 80 ° C were measured and introduced into the disc for 5 minutes. At the same time, water at 80 ° C was added in a dose of 1,000 ml / min by the four water feeds. The obtained duct suspension was filtered through a fluted filter and washed in portions with 1,000 ml of water in total. After that, the cellulose fibers were washed with about 200 ml of isopropanol and filled in the wet state with isopropanol. The nanocellulose still comprised 0.4% by weight of 1-ethyl-3-methylimidizolium acetate and around 95% of the cellulose fibers had a fiber thickness of 5 to 200 nm. Example 1
    [118] 200 ml of a 10% concentration of nanocellulose suspension was heated to 50 ° C. 0.25% by weight of cationic polymer A (solid polymer, based on dry nanocellulose) was added. In another container, the anionic polymer B was diluted with water by factor 10. The diluted dispersion of the anionic polymer B was then measured and introduced with gentle agitation to the heated nanocellulose suspension. The amount of acrylate resin used was 25% by weight (solid polymer, based on dry nanocellulose).
    [119] An aqueous cargo suspension with a concentration of 0.5% by weight was prepared starting from 100% mixed waste paper. The pH of the suspension was 7.1 and the charge opening was 50 ° Schopper-Riegler (° SR).
    [120] The treated nanocellulose suspension was added to the residual paper load with stirring. The measured amount of treated (solid) nanocellulose, based on the residual paper load (solid), was 5%. Sheets were then produced that have a base weight of 120 g / m2 from the waste paper load treated in a Rapid-Köthen sheet former according to ISO 5269/2. The leaves were dried by contact on one side with a metal cylinder heated under current for 7 minutes at 90 ° C. Example 2
    [121] 200 ml of a 10% concentration of nanocellulose suspension was heated to 30 ° C. In another container, the anionic polymer C was diluted with water by factor 10. The diluted dispersion was then measured and introduced with mild agitation to the heated nanocellulose suspension. The amount of acrylate resin used was 25% by weight (solid polymer, based on dry nanocellulose).
    [122] An aqueous cargo suspension with a concentration of 0.5% by weight was prepared from 100% mixed residual paper. The pH of the suspension was 7.1 and the charge opening was 50 ° Schopper-Riegler (° SR).
    [123] The treated nanocellulose suspension is added to the residual paper load with agitation. The measured amount of treated (solid) nanocellulose, based on the residual paper load (solid), was 5%. Sheets were then produced that have a base weight of 120 g / m2 from the waste paper load treated in a Rapid-Köthen sheet former according to ISO 5269/2. The leaves were dried by contact on one side with a metal cylinder heated under current for 7 minutes at 90 ° C. Example 3
    [124] 200 ml of a 10% concentration of nanocellulose suspension was initially treated at room temperature. 0.5% by weight of the cationic polymer A (solid polymer, based on dry nanocellulose) was added to it.
    [125] An aqueous suspension load was prepared at a concentration of 0.5% by weight starting from 100% mixed waste paper. The pH of the suspension was 7.1 and the charge opening was 50 ° Schopper-Riegler (° SR).
    [126] The treated nanocellulose suspension was added to the waste paper load with stirring. The measured amount of treated (solid) nanocellulose, based on the residual paper load (solid) was 5%. Sheets were then produced that had a base weight of 120 g / m2 starting from the load of waste paper treated in a Rapid-Köthen sheet former according to ISO 5269/2. The leaves were dried by contact on one side with a metal cylinder heated under current for 7 minutes at 90 ° C. Comparative example 1
    [127] An aqueous cargo suspension at a concentration of 0.5% by weight was prepared from 100% mixed residual paper. The pH of the suspension was 7.1 and the charge opening was 50 ° Schopper-Riegler (° SR).
    [128] Sheets were produced that have a base weight of 120 g / m2 from untreated waste paper filler in a Rapid-Köthen sheet former according to ISO 5269/2. The leaves were dried by contact on one side with a metal cylinder heated under current for 7 minutes at 90 ° C.
    [129] Comparative example 2, corresponding to the previous European patent application with the patent application number EP 09 150 237.7
    [130] An aqueous suspension load at a concentration of 0.5% by weight was prepared from 100% mixed waste paper. The pH of the suspension was 7.1 and the charge opening was 50 ° Schopper-Riegler (° SR).
    [131] Cationic polymer A was added in undiluted form to this fiber suspension. The amount of polymer used, based on the fiber content, was 0.3% by weight (solid polymer). The charge pre-treated with the cationic polymer was stirred carefully for around 30 seconds. In another container, the dispersion of anionic polymer B was diluted with water by factor 10. The diluted dispersion was then added with gentle agitation to the fiber charge suspension. The amount of acrylate resin used was 5% by weight (solid polymer, based on fiber content).
    [132] Sheets were produced that have a weight basis of 80 g / m2 from the pretreated fiber in a Rapid-Köthen sheet former according to ISO 5269/2. The leaves were dried by contact on one side with a metal cylinder heated under current for 7 minutes at 90 ° C. Test sheets of paper
    [133] After the sheets produced according to the examples and the Comparative Examples had been stored for 12 hours in a chamber conditioned at a constant temperature of 23 ° C and 50% atmospheric humidity, in each case the length of break the leaf dryness was determined in accordance with DIN 54 540. The CMT value of the conditioned leaves was determined in accordance with DIN 53 143 and the value of the dry burst pressure of the leaves was determined in accordance with DIN 53 141. The results are shown in table 1.Table 1
    权利要求:
    Claims (7)
    [0001]
    1. Process for the production of paper, cardboard and cardboard that have high dry resistance, characterized by the fact that an aqueous composition comprising an aqueous suspension comprising 0.1 to 25% by weight of nanocellulose and at least one polymer selected from the group consisting of an anionic polymer and a water-soluble cationic polymer is measured and introduced to the paper load, the paper load is drained and the paper products are dried, where the nanocellulose has a dimension of length below 1,000 pm and at least 80% of the nanocellulose cellulose fibers have a fiber thickness in the range of 50 pm to 3 nm, in which the anionic polymers comprise as polymerized units: (a) at least 60 mol% of at least one selected monomer of the group consisting of a C1- to C20-alkyl acrylate, a C1- to C2o-alkyl methacrylate, vinyl acetate, vinyl propionate, styrene, a-methylstyrene, p-methylstyrene, a-butylstyrene, 4-n -butilestiren o, 4-n-decylstyrene, acrylonitrile, methacrylonitrile, butadiene and isoprene; (b) 0.5 to 9 mol% of at least one anionic monomer of the group consisting of ethylenically unsaturated C3- to Cs-carboxylic acids incorporated as polymerizable units; (c) optionally at least one monomer selected from the group consisting of Ci- to Cio-hydroxyalkyl acrylate, Ci- to Cio-hydroxyalkyl methacrylate, acrylamide, methacrylamide, an N-Ci- to C20-alkylacrylamide and an N-Ci - C2o-alkylmethacrylamide and, (d) optionally, a monomer comprising at least two ethylenically unsaturated double bonds in the molecule, and in which a polymer comprising vinylamine units is used as the water-soluble cationic polymer.
    [0002]
    2. Process according to claim 1, characterized by the fact that the nanocellulose further comprises from 5 ppm to 2% by weight of an ionic fluid.
    [0003]
    Process according to claim 1, characterized by the fact that the anionic polymer comprises at least 80 mol% of at least one monomer of the group (a) incorporated in the form of polymerized units.
    [0004]
    4. Process according to claim 3, characterized by the fact that the anionic polymers comprise, as the monomer of the group (a), mixtures of (i) a C1- to C2o-alkyl acrylate and / or a Ci methacrylate - C20-alkyl; and (ii) styrene, a-methylstyrene, p-methylstyrene, a-butylstyrene, 4-n-butylstyrene, butadiene and / or isoprene in a weight ratio of from 10:90 to 90:10 incorporated in the form of polymerized units.
    [0005]
    Process according to any one of claims 1 to 4, characterized in that the molar mass Mw of the cationic polymers is in the range of 5,000 to 5 million g / mol.
    [0006]
    Process according to any one of claims 1 to 5, characterized in that the charge density of the cationic polymer is in the range of 0.5 to 23 meq / g.
    [0007]
    7. Aqueous composition, characterized by the fact that it comprises an aqueous suspension comprising 0.1 to 25% by weight of nanocellulose and at least one polymer selected from the group consisting of an anionic polymer and a water-soluble cationic polymer, in that the nanocellulose has a length dimension below 1,000 pm and at least 80% of the nanocellulose cellulose fibers have a fiber thickness in the range of 50 pm to 3 nm, in which the anionic polymers comprise as polymerized units: (a) at least 60 mol% of at least one monomer selected from the group consisting of C1- to C20-alkyl acrylate, C1- to C20-alkyl methacrylate, vinyl acetate, vinyl propionate, styrene, α-methylstyrene , p-methylstyrene, α-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene, acrylonitrile, methacrylonitrile, butadiene and isoprene; (b) 0.5 to 9 mol% of at least one anionic monomer of the group consisting of ethylenically unsaturated C3- to Cs-carboxylic acids incorporated as polymerizable units; (c) optionally at least one monomer selected from the group consisting of Ci- to Cio-hydroxyalkyl acrylate, Ci- to Cio-hydroxyalkyl methacrylate, acrylamide, methacrylamide, an N-Ci- to C20-alkylacrylamide and an N-Ci - C2o-alkylmethacrylamide and, (d) optionally, a monomer comprising at least two ethylenically unsaturated double bonds in the molecule, and in which a polymer comprising vinylamine units is used as the water-soluble cationic polymer.
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    同族专利:
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    US8647470B2|2014-02-11|
    US20120205065A1|2012-08-16|
    JP2013508568A|2013-03-07|
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    法律状态:
    2018-04-10| B06F| Objections, documents and/or translations needed after an examination request according art. 34 industrial property law|
    2019-03-06| B06T| Formal requirements before examination|
    2019-04-30| B11E| Dismissal acc. art. 34 of ipl - requirements for examination incomplete|
    2019-05-07| B11N| Dismissal: publication cancelled|Free format text: ANULADA A PUBLICACAO CODIGO 11.5 NA RPI NO 2521 DE 30/04/2019 POR TER SIDO INDEVIDA. |
    2020-05-26| B09A| Decision: intention to grant|
    2020-10-13| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 14/10/2010, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    EP09173497|2009-10-20|
    EP09173497.0|2009-10-20|
    PCT/EP2010/065375|WO2011048000A1|2009-10-20|2010-10-14|Method for producing paper, paperboard and cardboard having high dry strength|
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