• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention makes it possible to manufacture, at a high yield, transfer paper for inorganic substrates which makes it possible to properly transfer a desired image onto an inorganic substrate by using inkjet printing. The inject ink disclosed herein contains inorganic solids, and a photocurable monomer component. The monomer component includes at least a monofunctional acrylate monomer, a monofunctional N-vinyl compound monomer, and a polyfunctional vinyl ether monomer. If the total weight of the monomer component is 100 mass%, the weight of the monofunctional acrylate monomer is 40-96 mass%, the weight of the monofunctional N-vinyl compound monomer is 2-20 mass%, and the weight of the polyfunctional vinyl ether monomer is 2-40 mass%. The ink makes it possible to manufacture, at a high yield, transfer paper which makes it possible to properly transfer a crack-free image while maintaining high levels of both photocurability during UV irradiation and flexibility after photocuring.
    公开号:ES2858516A2
    申请号:ES202190048
    申请日:2019-12-27
    公开日:2021-09-30
    发明作者:Tomoshi Kumazawa；Hiromichi Hayashi；Yuuki Arakawa
    申请人:Noritake Co Ltd；
    IPC主号:
    专利说明:

    [0004] BACKGROUND OF THE INVENTION
    [0006] Technical field
    [0007] The present invention relates to inkjet ink, and more specifically, inkjet ink, for a transfer sheet, which is usable to draw an image on a transfer sheet for an inorganic substrate. The present application claims priority based on Japanese Patent Application No. 2019-034699 filed on February 27, 2019, the entirety of which is incorporated herein by reference.
    [0009] Prior state of the art
    [0010] Inkjet printing has been conventionally used as one of the printing methods for drawing a desired image such as a pattern, a letter or the like on a printing target. Such inkjet printing enables a high-precision image to be drawn with a simple and low-cost device and is therefore used in various fields. Recently, the use of the aforementioned inkjet printing has been studied to draw an image on an inorganic substrate such as a ceramic substrate (for example, a ceramic or porcelain article, or a ceramic tile), a glass substrate , a metallic substrate or the like. Specifically, for drawing a pattern, a letter or the like in the field of the inorganic substrate, handwriting, plate printing or the like have been conventionally used. However, inkjet printing does not require skilled labor, which is required with handwriting, and can be done quickly on demand unlike plate printing. Therefore, inkjet printing is now a target of attention from the point of view of improving productivity.
    [0012] However, inkjet printing in the field of inorganic substrates still has a lot of room for improvement. Because, it is difficult to convert inkjet printing technology in a no-bake target field (paper, cloth or the like) to inkjet printing technology in the field. of inorganic substrates. For example, for a product using an inorganic substrate (inorganic article), an inorganic substrate that has an image drawn on it is occasionally fired at 500 ° C or higher (for example, 500 ° C to 1200 ° C). In this case, if used inkjet ink for paper, fabric or the like is used, the pigment may possibly become discolored (or discolored) undesirably during cooking. Therefore, the inkjet ink to be used for an inorganic substrate to be fired (inkjet ink for an inorganic substrate) should have a proportionate composition in consideration of the firing. Examples of inkjet ink for an inorganic substrate include the inkjet ink described in, for example, Patent Bibliography 1 and Patent Bibliography 2. The ink described in these documents is photocurable ink that includes a component photocurable monomer.
    [0014] Also, a surface of an inorganic substrate such as a printing target occasionally has a curved surface or a convex or concave portion formed on it. An attempt to directly draw an image onto a surface of an inorganic substrate that has a curved surface or the like results in a warped line or the like and there is a possibility that the clarity of the image will deteriorate significantly or the desired image may not be able to be drawn. For this reason, when drawing an image on an inorganic substrate having a curved surface or the like, a transfer sheet is used for an inorganic substrate. Specifically, the transfer sheet that draws the desired image sticks to the inorganic substrate while curving in accordance with the curved surface or the like of the inorganic substrate. By this, the desired image is transferred to the inorganic substrate. To draw an image on such a transfer sheet, screen printing has been used. From the point of view of improving productivity, it has recently been proposed to use inkjet printing. For example, Patent Bibliography 3 discloses a technology for forming a transfer sheet for the ceramic industry. The decorating method described in Patent Bibliography 3 includes a step of forming a starch layer on a surface of a mounting paper, a step of forming a porous fixing layer on a surface of the starch layer, a step of making the inorganic pigment ink adhere to a surface of the porous fixing layer using inkjet printing and a step of forming a frit layer to fix the inorganic pigment ink.
    [0015] LIST OF APPOINTMENTS
    [0017] PATENT DOCUMENT
    [0018] Patent Bibliography 1: Japanese Patent No. 06083484
    [0019] Patent Bibliography 2: Japanese Patent No. 05708918
    [0020] Patent Bibliography 3: Japanese Patent Publication Open for Public Inspection N.02009-154419
    [0022] Brief description of the invention
    [0024] Technical problem
    [0025] However, the technology described in Patent Bibliography 3 requires the formation of a porous fixing layer and a frit layer on the surface of the base sheet to fix the ink on the surface of the transfer sheet. Therefore, it is difficult for the technology described in Patent Bibliography 3 to contribute to improving productivity, which is one of the objects of inkjet printing.
    [0027] The present invention, made in the light of said point, has a main object of providing a technology for producing with high productivity a transfer sheet suitable for transferring a desired image to an inorganic substrate, through the use of inkjet printing. ink.
    [0028] Solution to the problem
    [0030] The present inventors envisioned the use of photocurable ink that is fixed to a printing target by ultraviolet (UV) irradiation, as a method of fixing ink to a surface of a transfer sheet without forming a layer for fixing as described. in Patent Bibliography 3. However, the use of general photocurable ink for an inorganic substrate to produce a transfer sheet caused another problem that the image (an ink after light curing) cracks when the transfer sheet is curved from according to the shape of the inorganic substrate. Based on this, the present inventors conceived that the ink for a transfer sheet needs to be redeveloped taking into consideration the flexibility of the cured ink because the general photocurable ink for an inorganic substrate is not usable for a transfer sheet for an inorganic substrate. . As a result of conducting various experiments and studies with ink that is sufficiently photocurable to properly fix on a surface of a transfer sheet and is flexible enough to prevent cracking after photocuring, the present inventors envisioned inkjet ink as disclosed herein.
    [0032] The inkjet ink disclosed herein is based on the knowledge described above and is usable for a transfer sheet for an inorganic substrate. Inkjet ink comprises an inorganic solids content including an inorganic pigment and glass; and a photocurable monomer component. The monomer component includes at least one monofunctional acrylate-based monomer containing an acryloyl group or a methacryloyl group in a molecule, a monofunctional N-vinyl compound monomer containing a nitrogen-containing compound, and a vinyl group attached to a nitrogen atom. nitrogen (N) of the nitrogen-containing compound and a polyfunctional vinyl ether-based monomer containing at least two vinyl ether groups in one molecule. In the ink for inkjet disclosed herein, the monofunctional acrylate-based monomer is contained in a weight ratio of 40% by mass to 96% by mass relative to 100% by mass as the total weight of the monomer component. , the monofunctional N-vinyl compound monomer is contained in a weight ratio of 2% by mass to 20% by mass with respect to 100% by mass as the total weight of the monomer component and the polyfunctional monomer based on vinyl ether is contained in a weight ratio of 2% by mass to 40% by mass with respect to 100% by mass as the total weight of the monomer component.
    [0034] As described below in detail, the inkjet ink having the above composition has sufficient light curing to be fixed to a surface of a transfer sheet preferentially, and high flexibility that can prevent cracking of the ink after light curing. Therefore, by using the inkjet ink disclosed herein, a transfer sheet, it is possible to produce a transfer sheet suitable for transferring an image without cracking to an inorganic substrate with high productivity.
    [0036] In a preferred embodiment of the inkjet ink disclosed herein, the monofunctional acrylate-based monomer contains at least one selected from the group consisting of benzylacrylate, phenoxyethylacrylate, and cyclic trimethylolpropane formalacrylate. These are highly flexible after light curing, among the monofunctional acrylate-based monomers. Therefore, these monomers are suitable to prevent the ink from cracking when the transfer sheet is curved.
    [0038] In a preferred embodiment of the inkjet ink disclosed herein, the monofunctional N-vinyl compound monomer is N-vinyl-2-caprolactam. Among the monomers of monofunctional N-vinyl compounds, N-vinyl-2-caprolactam is highly photo-curable. Therefore, this monomer can improve the surface fixation ability of the transfer sheet more preferably. Furthermore, N-vinyl-2-caprolactam can increase the stretchability after the ink is light-cured and thus suppresses the appearance of cracks.
    [0040] In a preferred embodiment of the inkjet ink disclosed herein, the polyfunctional vinyl ether-based monomer contains at least one selected from the group consisting of diethylene glycol vinyl ether, triethylene glycol vinyl ether, and 1,4-cyclohexanedimethaneol vinyl ether. These are highly photocurable among polyfunctional vinyl ether-based monomers and are of low stiffness. Thus, these monomers can have both high binding ability to the substrate surface and high flexibility after light curing.
    [0042] In a preferred embodiment of the inkjet ink disclosed herein, the inorganic solid content is contained in a weight ratio of 20% by mass to 50% by mass relative to 100% by mass as the total weight of inkjet ink. The weight ratio of the inorganic solid content in the ink is set in a range, so that the ejection ease of the ink jet device and the color developing property of the ink after cooking can be preferably improved.
    [0044] The present invention provides a method of producing a transfer sheet for an inorganic substrate. The method comprises a step of adhering any of the inkjet inks disclosed herein to a surface of a base sheet using an inkjet device, and a step of curing the adhering inkjet ink. to the surface of the base sheet radiating UV rays towards the surface of the base sheet. With such a production method, a transfer sheet can be produced which allows a crack-free image to transfer properly onto an inorganic substrate with high productivity.
    [0046] In another aspect of the present invention, a transfer sheet suitable for an inorganic substrate to be fired is provided. The transfer sheet comprises a base sheet; and an image portion containing a cured body of any of the inkjet inks disclosed herein. As described above, the image drawn with the ink described above is sufficiently flexible, and therefore it can prevent the ink from cracking when the transfer sheet is bent according to the shape of the substrate.
    [0048] The present invention provides a method of producing an inorganic article that includes a decorative part. The method comprises a step of gluing the transfer sheet according to claim 7 to a surface of an inorganic substrate and a step of cooking the inorganic substrate under a condition that the highest firing temperature is set in a range of 500 ° C to 1200 ° C. With such a production method, a favorable decorative part without cracks can be formed even if the inorganic substrate having a curved surface or the like is the decoration target.
    [0050] BRIEF DESCRIPTION OF THE DRAWINGS
    [0052] [FIG. 1] FIGURE 1 is a cross-sectional view schematically showing a stirring and spraying device usable for producing ink for inkjet.
    [0054] [FIG. 2] FIGURE 2 is a general view schematically showing an example of an ink jet device.
    [0056] [FIG. 3] FIGURE 3 is a cross-sectional view schematically showing an ink jet head in the ink jet device shown in FIGURE 2.
    [0057] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
    [0059] Hereinafter, preferred embodiments of the present invention will be described. Items that are other than items specifically referenced in this specification and that are necessary to carry out the present invention may be understood as a matter of design based on prior art and known to one skilled in the art. . The present invention can be carried out based on the contents disclosed in this specification and common technological knowledge in the art.
    [0061] 1. Inkjet ink
    [0062] The inkjet ink disclosed herein is inkjet ink, for a transfer sheet, which is usable to draw an image on a transfer sheet for an inorganic substrate. Said inkjet ink comprises at least an inorganic solids content and a monomer component that is photocurable (photocurable monomer component). Hereinafter, the components of the ink jet ink disclosed herein will be described.
    [0064] (1) Inorganic solid content
    [0065] An inorganic solid content forms a main component of a printing layer (decorative part) after firing. The inorganic solid content includes an inorganic pigment and glass.
    [0067] (a) Inorganic pigment
    [0069] An inorganic pigment is added to the ink to develop a desired color on a surface of a substrate after firing. The inorganic pigment can contain, for example, a metallic compound. Said inorganic pigment has a high thermal resistance. Therefore, the pigment can be prevented from fading (or discoloring) while firing at 500 ° C or higher (e.g. 500 ° C to 1200 ° C) after an image is transferred to an inorganic substrate. from a transfer sheet. A specific example of such an inorganic pigment can be a composite metal compound containing at least one metal element from the group consisting of Cu, Mn, Zr, Ti, Pr, Cr, Sb, Ni, Co, Al and Cd. Among these , a rust Zr-based composite metal containing mainly Zr (eg ZrSiÜ 4 ) is preferably especially usable from the point of view of thermal resistance. For example, general inkjet printing combines three-color ink of cyan, yellow, and magenta to draw an image of a desired color. In the case that the above-mentioned Zr-based composite metal oxide is used as an inorganic pigment, the Zr-based composite metal oxide can be doped with a predetermined metal element to obtain inorganic pigments of the three colors mentioned above. The Zr-based composite metal oxide for cyan may be, for example, ZrSiÜ 4 -V (vanadium). The Zr-based composite metal oxide for yellow can be, for example, ZrSiÜ 4 -Pr (praseodymium). The Zr-based composite metal oxide for magenta can be, for example, ZrSi04-Fe (iron).
    [0071] A certain type of inkjet device can use black ink or white ink in addition to the ink of the three colors mentioned above. A preferably usable inorganic pigment for black ink is, for example, an FeCr-based metal composite compound (eg, spinel black). Meanwhile, an inorganic pigment usable preferably for white ink is, for example, TiO2, ZRU 2, ZnO, ZrSiÜ4 or similar.
    [0073] Inorganic pigment is not limited to any of the materials listed above. For the inkjet ink disclosed herein, any usable inorganic ink pigment for an inorganic substrate is usable without specific limitation as long as most of the effect of the present invention is not spoiled.
    [0075] An inorganic pigment is normally in the form of particles. It is preferred that said inorganic pigment in particulate form has an appropriately adjusted particle diameter taking into consideration the diameter of an ejection opening of an ink jet device described below. If the particle diameter of the inorganic pigment is too large, the inorganic pigment can undesirably clog the ejection opening and decrease the ejection ease of the ink. A general inkjet device has an ejection opening that has a diameter of about 15 µm to about 60 pm (eg, 25 pm). Therefore, it is preferred that the inorganic pigment particles are made microscopic to have a particle diameter D 100 (maximum particle diameter) of 5 p, m or shorter (preferably 1 ^ m or shorter). The particle diameter D 100 of the inorganic pigment can be measured, for example, as the value of 100% of the cumulative particle diameter considered from the microfine particle side in the cumulative particle size distribution obtained when a dispersion method is adopted. dynamic light.
    [0077] The inorganic pigment can be made up of inorganic particles mixed and dispersed in glass which is described below. Said inorganic particles can be, for example, nanometallic particles. Examples of nano-metallic particles include nano-gold particles, nano-silver particles, nano-copper particles, nano-platinum particles, nano-titanium particles, nano-palladium particles, and the like. Nanometallic particles of each type have inherent optical characteristics (eg, a strong light absorption band) in a region from ultraviolet to visible light due to surface plasmon resonance (SPR). For example, nano-gold (Au) particles absorb light of a wavelength of around 530 nm (green to sky-blue light) and develop a bluish-red (reddish purple) color called "garnet." Therefore, in the case where, for example, red or purple ink is to be prepared, the nano-gold particles can preferably be usable as the nano-metallic particles. For example, nano silver (Ag) particles absorb light of a wavelength of around 420 nm (blue light) and develop a yellow color. Therefore, in the case where, for example, orange or yellow ink is to be prepared, the nanosilver particles may preferably be usable as the nano-metallic particles.
    [0079] In a preferred embodiment, the nanometallic particles have a D5o particle diameter of 5nm or longer, typically 10nm or longer, eg, 15nm or longer. In another preferred embodiment, the nanometallic particles have a particle diameter D5o of generally 80 nm or shorter, typically 50 nm or shorter, eg, 30 nm or shorter. The particle diameter D5o is set to a value in the range mentioned above, so that the nanometallic particles have an increased absorbance in light of a specific wavelength and therefore can develop any of several colors even when incorporated in a small amount. Furthermore, the aforementioned range of the particle diameter D5o allows a fine image to be drawn with less color irregularities.
    [0081] (b) Glass
    [0083] Glass is melted by cooking the inorganic. Afterwards, the molten glass is solidified by cooling treatment. In this way, glass causes inorganic pigment to fix on the surface of a substrate. Also, the glass has the function of coating the inorganic pigment after cooling, to form an image with a beautiful luster.
    [0085] Examples of glass that may be of such a nature include glass based on SÍO2-B2O3, glass based on SÍO2-RO (RO represents an oxide of a group II element, for example, MgO, CaO, SrO or BaO; that is, applicable to the following description), glass based on SÍO2-RO-R2O (R2O represents an oxide of an alkaline metal element, for example, LÍ2O, Na2Ü, K2O, Rb2Ü, CS2O or Fr2Ü, specifically, LÍ2O; this is applicable to the following description), glass based on SÍO2-B2O3-R2O, glass based on Si02-R0-Zn0, glass based on Si02-R0-Zr02, glass based on SÍO2-RO-AI2O3, glass based on SÍO2-RO-BÍ2O3, glass based on SÍO2-R2O, glass based on Si02-Zn0, glass based on Si02-Zr02, glass based on SÍO2-AI2O3, glass based on RO-R2O, glass based on RO-ZnO. Each of these types of glass can contain one, or two or more, components in addition to the main component represented by the name of the glass. The glass can be crystalline glass containing a crystal, rather than general amorphous glass.
    [0087] In a preferred embodiment, the SIO 2 occupies at least half (50% by moles) with respect to 100% by moles, which is the entire glass. The SIO 2 ratio can be about 80% by mole or less. From the point of view of improving the melting ability of the glass, a component such as RO, R2O, B2O3 or the like can be incorporated. In a preferred embodiment, RO occupies 0 to 35% by mole relative to 100% by mole as the entire glass. In another preferred embodiment, R20 occupies 0 to 10% by mole relative to 100% by mole as the entire glass. In yet another preferred embodiment, B2O3 occupies 0 to 30% by mole relative to 100% by mole as all of the glass.
    [0089] In a preferred embodiment, the glass is made of a multi-component material A containing four or more components (for example, five or more components). Such an arrangement improves physical stability. For example, such a component as AI2O3, ZnO, CaO, ZrÜ2 or the like can be incorporated in a proportion of, for example, 1% by mole or more. Such an arrangement can improve the chemical durability or abrasion resistance of a decorative part. In a preferred embodiment, AI2O3 occupies 0 to 10% by mole relative to 100% by mole as the entire glass. In a preferred embodiment, ZrÜ 2 occupies 0 to 10 mol% with respect to 100 mol% as the whole of the glass.
    [0091] A preferred embodiment of the glass disclosed herein may be borosilicate glass having the following composition with the molar ratios converted to those of an oxide, relative to 100 mole% as all glass:
    [0092] SIO 2 40 to 70% by mole (eg 50 to 60% by mole);
    [0093] B2O3 10 to 40% by mole (for example, 20 to 30% by mole);
    [0094] R 2 O (at least one of LÍ 2 O, Na 2 Ü, K 2 O and Rb 2 Ü) from 3 to 20% by moles (for example, from 5 to 10% by moles);
    [0095] AI2O3 from 0 to 20% by mole (for example, from 5 to 10% by mole); and ZrÜ 2 from 0 to l10 mol% (for example, 3 to 16 mol%).
    [0097] The ratio of SIO 2 to the entire glass matrix of said borosilicate glass can be, for example, 40% by moles or more and usually 70% by moles or less, for example, 65% by moles or less. The ratio of B 2 O 3 with respect to the entire glass matrix can be normally 10 mol% or more, for example 15 mol% or more and usually 40 mol% or less, for example the 35% by mole or less. The ratio of R 2 O to the entire glass matrix can be normally 3 mol% or more, for example 6 mol% or more and usually 20 mol% or less, for example 15 % in moles or less. In a preferred embodiment, the borosilicate glass contains LÍ 2 O, Na 2 Ü and K 2 O as R 2 O. The ratio of Li20 to the entire glass matrix can be, for example, 3% by mole or more and 6% by mole or less. The ratio of K20 to the entire glass matrix can be, for example, 0.5 mole% or more and 3 mole% or less. The ratio of Na 2 * to the entire glass matrix can be, for example, 0.5 mol% or more and 3 mol% or less. The ratio of AI 2 O 3 with respect to the entire glass matrix can be normally 3% by mole or more and normally 20% by mole or less, for example, 15% by mole or less. The ratio of Zr02 to the entire glass matrix can be usually 1% by mole or more and usually 10% by mole or less, for example 8% by mole or less.
    [0099] Borosilicate glass may contain an additional component other than the above. Examples of such additional component include, in the state of an oxide, BeO, MgO, CaO, SrO, BaO, ZnO, Ag20, TIO 2 , V 2 O 5 , FeO, Fe203, Fe304, CuO, Cu20, Nb 2 05 , P 2 O 5 , La 20 3 , Ce02, BÍ 2 O 3 , Pb 20 3 and the like. The additional components may be contained in a ratio of about 10% by mole or less in total relative to 100% by mole as the entire glass matrix.
    [0101] Another example of the glass disclosed herein may be glass having the following composition contained in a ratio of 90 mole% or more with the mole ratios converted to an oxide, relative to 100 mole% as the whole of glass:
    [0102] SIO 2 45 to 70% by mole (eg 50 to 60% by mole);
    [0103] Sn02 0.1 to 16% by mole (eg, 1 to 15% by mole);
    [0104] ZnO 1-15% by mole (eg, 4-11% by mole);
    [0105] RO (at least oneBeO, MgO, CaO, SrOyBaO) 15 to 35 mol% (eg 20 to 30 mol);
    [0106] R 2 O (at least one of LI 2 O, Na20, K 2 O and Rb20) 0 to 5% by mole (for example, 1 to 5 moles); and
    [0107] B2O3 0 to 13 mol% (eg 0 to 11 mol%).
    [0109] The ratio of SIO 2 to the entire glass matrix of the glass having such a composition can be, for example, 50% by mole or more and usually 65% by mole or less, for example, 60% by moles or less. The ratio of Sn02 to the entire glass matrix can be normally 0.5% by mole or more, for example 1% by mole or more and usually 5.5% by mole or less, for example, 5% by mole or less. The ratio of ZnO to the entire glass matrix can be normally 2% by mole or more, for example 4% by mole or more and usually 12% by mole or less, for example 10% by moles or less. The ratio of RO to the entire glass matrix can be typically 18% by mole or more, for example 20% by mole or more and usually 32% by mole or less, for example 30% by moles or less. The ratio of R20 to The entire glass matrix may generally be 0.1 % by mole or more, for example 1% by mole or more and, for example, 3% by mole or less. The ratio of B 2 O 3 to the entire glass matrix can usually be 1 mole% or less, for example 0.1 mole% or less.
    [0111] The glass described above may contain an additional component other than the above. Examples of such additional component include, in the state of an oxide, Ag 2 0 , AI2O3, Zr 0 2 , TIO2, V2O5, FeO, Fe 2 Ü 3 , Fe 3 Ü 4 , CuO, CU2O, Nb20s, P2O5, La 2 Ü 3 , Ce 0 2 , BÍ2O3 and the like. The additional components may be contained in a ratio of about 10 % by mole or less in total relative to 10 % by mole as the entire glass matrix.
    [0113] It is preferred that the glass has a linear thermal expansion coefficient (average linear thermal expansion coefficient measured in a temperature range of 25 ° C to 500 ° C using a thermomechanical analyzer; this applies to the following description) of , for example, 4.0 '10 ' 6 K -1 to 8.0 '10 ' 6 K-1. With a linear thermal expansion coefficient, the difference in the contraction ratio between the glass and a decoration target (inorganic substrate) at the time of firing decreases and the decorative part becomes difficult to exfoliate or crack. There is no specific limitation on the deformation point of the glass. The deformation point can be, for example, 400 ° C to 700 ° C. There is no specific limitation on the transition point (Tg value based on differential scanning calorimetry; this applies to the following description) of the glass. The transition point can be, for example, 400 ° C to 700 ° C.
    [0115] The glass can normally be in the form of particles. The particle diameter of such a particle-type glass influences the viscosity of the ink. Therefore, it is preferred that the diameter of the particles is appropriately adjusted taking into consideration the ease of ejection from the ink jet device. Specifically, in the case that the ink includes glass with a long particle diameter, the ejection opening can be easily clogged undesirably to reduce the ejection ease. Therefore, it is preferred that the particle diameter of the glass is controlled such that the maximum particle diameter (particle diameter D 100 ) is 1 µm or shorter (preferably 0.85 pm or shorter). The particle diameter D 100 of the glass can be measured, for example, as the value of 100% of the particle diameter Cumulative considered from the microfine particle side in the cumulative particle size distribution obtained when a dynamic light scattering method is adopted.
    [0117] In the inkjet ink disclosed herein, the glass has a mass ratio of preferably 65% by mass or more, more preferably 70% by mass or more, and even more preferably 75% by mass or more with respect to at 100% by weight, which is the total weight of the inorganic solids content. With such a mass ratio, an image having a beautiful gloss can be formed on a surface of an inorganic substrate after firing. From the viewpoint of ensuring that the content of the inorganic pigment is a predetermined level or higher to maintain the color developing property after firing, the mass ratio of the glass is preferably 90% by mass or less, more preferably 85% by mass or less and even more preferably 80% by mass or less.
    [0119] The inorganic solid content has a mass ratio (ratio of the total mass of the inorganic pigment and the glass) of, preferably 20% by mass or more, more preferably 25% by mass or more, and still more preferably 30% by mass. mass or more with respect to 100% by weight, which is the total weight of the ink. With such a mass ratio, the ejection ease and the color development property after firing of the ink can be more preferably improved. From the viewpoint of suppressing an increase in ink viscosity, the mass ratio of the inorganic solid content is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably the 40% by mass or less.
    [0121] (2) Light-curing monomer component
    [0123] The inkjet ink disclosed herein is photocurable inkjet ink comprising a monomer component having photocurable (photocurable monomer component). The "photocurable monomer component" in this specification refers to a material that is normally in liquid form and contains at least one type of monomer from a polymerized (or cross-linked) resin and cured when irradiated with light (eg, Ray ultraviolet). The use of the ink comprising said photocurable monomer component allows ink having a sufficient thickness to fix on a surface of a transfer sheet without the need to form an ink fixation layer such as a porous fixation layer, a layer of frit or the like on the transfer sheet.
    [0125] The photocurable monomer component disclosed herein includes at least one (a) monofunctional acrylate-based monomer, (b) monofunctional N-vinyl compound monomer, and (c) polyfunctional vinyl ether-based monomer. The use of a photocurable monomer that includes monomers (a) to (c) in a predetermined ratio can provide inkjet ink that has both high photocurability when UV irradiated and high flexibility after photocuring. Hereinafter, monomers (a) to (c) will be specifically described.
    [0127] (a) Monofunctional acrylate-based monomer
    [0128] A monofunctional acrylate-based monomer is a compound that contains an acryloyl group (CH 2 = CHCOO-) or a methacryloyl group (CH 2 = CCH 3 COO-) in one molecule.
    [0130] A monofunctional acrylate-based monomer is highly capable of diffusing an inorganic solid content and can suppress an increase in ink viscosity, and therefore can contribute to the preparation of ink having a preferred ejecting ease. Among the photocurable monomers, the monofunctional acrylate-based monomer has the characteristic of being relatively low in stiffness (high in flexibility) after photocuring. Therefore, the inkjet ink disclosed herein includes a monofunctional acrylate-based monomer at 40% by mass or more relative to 100% by mass, which is the total weight of the photocurable monomer component, to provide high flexibility. after photocuring. From the viewpoint of offering even better flexibility, the weight ratio of the monofunctional acrylate-based monomer is preferably 45% by mass or more, more preferably 50% by mass or more, even more preferably 55% by mass. or more and especially preferably 60% by mass or more.
    [0132] Meanwhile, monofunctional acrylate-based monomer tends to be relatively low in photocurability. Therefore, the inkjet ink disclosed herein includes the monofunctional acrylate-based monomer at 96% by mass or less and has a highly photo-curable monomer described below incorporated into the photo-curable monomer component, so that it is certainly fixable to a surface of an inorganic substrate. From the viewpoint of offering even better photocurability, the weight ratio of the monofunctional acrylate-based monomer is preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass. or less and especially preferably 78% by mass or less.
    [0134] Specific examples of the monofunctional acrylate-based monomer include benzylacrylate, cyclic trimethylolpropane-formalacrylate, phenoxyethylacrylate, isobornylacrylate, tetrahydrofurfurylacrylate, methoxyethylacrylate, cyclohexylaxocrylate, ethylcarbitolacrylate, (2-ethylcarbitolacrylate, (2-4-ethylmethyl acrylate, (2-ethylcarbitolacrylate), (2-4-ethyl-methyl-1,3-ethyl) acrylate, (2-ethylcarbitolacrylate) hydroxypropylacrylate, 4-hydroxybutylacrylate, methyl (meth) acrylate, ethylacrylate, propylacrylate, butylacrylate, pentylacrylate, n-stearylacrylate, butoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (2) acrylate (methyl) acrylate, isobornyl (2) acrylate (meth) acrylate 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, tbutylcyclohexyl (meth) acrylate, isoamylacrylate, lauryl (meth) acrylate, octylacrylate, isooctonylacrylate, isooctonylacrylate isodecylacylate, tridecyl (meth) acrylate, isomyristyl acrylate, isostearylacrylate, 2-ethylhexylacrylate, 2-ethylhexyl-diglycolacrylate, 4-hydroxybutylacrylate, methoxydyethylenegl icolacrylate, methoxytriethyleneglycolacrylate, ethoxydyethyleneglycolacrylate, 2- (2-ethoxyethoxy) ethylacrylate, 2-ethylhexylcarbitolacrylate, phenoxyethoxyethylacrylate, and the like. The (meth) acrylate compounds listed above can be used independently or in a combination of two or more. Among these monofunctional acrylate-based monomers, benzylacrylate, phenoxyethylacrylate, and cyclic trimethylolpropane-formacrylate are especially highly flexible after photocuring and therefore can preferably prevent the ink from cracking when the transfer sheet is curved.
    [0136] (b) Monofunctional N-vinyl compound monomer
    [0138] A monofunctional N-vinyl compound monomer is a compound containing a nitrogen-containing compound and a vinyl group attached to a nitrogen atom (N) of the nitrogen-containing compound. In this document, the "vinyl group" refers to CH2 = CR1- (in which R1 is a hydrogen atom or an organic group).
    [0140] A monofunctional N-vinyl compound monomer can increase the stretchability after the ink is light-cured to suppress the appearance of cracks. Among the photocurable monomers, the monofunctional N-vinyl compound monomer is highly photocurable and has the function of improving the fixing ability of ink to the surface of a transfer sheet. Therefore, the ink for inkjet disclosed herein includes a monofunctional N-vinyl compound monomer in a weight ratio of 2% by mass or more to 100% by mass as the total weight of the monomer component. photocurable, to be sufficiently photocurable with certainty to improve the ability of fixation of the same to the inorganic substrate. From the viewpoint of providing even higher binding capacity, the weight ratio of the monofunctional N-vinyl compound monomer is preferably 3% by mass or more, more preferably 4% by mass or more, and even more preferably 5% by mass or more.
    [0142] Meanwhile, there is a tendency for the incorporation of the monofunctional N-vinyl compound monomer to increase the stiffness (decrease the flexibility) of the cured ink. Therefore, from the viewpoint of preventing the occurrence of cracks after the ink is light-cured, the weight ratio of the monofunctional N-vinyl compound monomer in the ink for inkjet disclosed herein is set forth in the 20% by mass or less. From the viewpoint of preventing the occurrence of cracks more preferably after the ink is light-cured, the content of the monofunctional N-vinyl compound monomer is preferably 17% by mass or less, more preferably 15% by mass or less. , even more preferably 13% by mass or less and especially preferably 10% by mass or less.
    [0144] The monofunctional N-vinyl compound monomer described above is represented by, for example, the following general formula (1).
    [0145] CH2 = CR1 - NR2R3 (1)
    [0147] In the general formula (1) shown above, R1 is a hydrogen atom; or an alkyl group, a phenyl group, a benzyl group or a halogen group containing a number of carbon atoms from 1 to 4. Among these, R1 is preferably a hydrogen atom or an alkyl group containing a number of carbon atoms from 1 to 4 and is more preferably a hydrogen atom. R2 and R3 can each be a group selected from a hydrogen atom; and an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an alkoxy group, an alkoxyalkyl group, an alkylol group, an acetyl group (CH3CO-), and an aromatic group that may contain a substituent. R2 and R3 can be the same as, or different from, each other. The alkyl group, alkenyl group, alkynyl group, aralkyl group, alkoxy group, alkoxyalkyl group, alkylol group, and acetyl group that may contain a substituent may each contain a total number of carbon atoms from 1 to 20. The alkyl group, the alkenyl group, the alkynyl group, the aralkyl group, the alkoxy group, the alkoxyalkyl group, the alkylol group and the acetyl group that may contain a substituent may be of the chain or cyclic type and are preferably of the chain. The aromatic group is an aryl group that can contain a substituent. The aromatic group can contain a total number of carbon atoms from 6 to 36. The substituent that can be contained in the alkyl group, the alkenyl group, the alkynyl group, the aralkyl group, the alkoxy group, the alkoxyalkyl group, the group The alkylol, the acetyl group and the aromatic group contain, for example, a hydroxy group or a halogen atom such as a fluorine atom, a halogen atom or the like. With respect to the general formula (1) shown above, R2 and R3 can be joined together to form a cyclic structure.
    [0149] Preferred embodiments of the monofunctional N-vinyl compound monomer include N-vinyl-2-caprolactam, N-vinyl-2-pyrrolidone, N-vinyl-3-morpholinone, N-vinylpiperidine, N-vinylpyrrolidine, N-vinylazidine, N- vinylazetidine, N-vinylimidazole, N-vinylmorpholine, N-vinylpyrazole, N-vinylvalerolactam, N-vinylcarbazole, N-vinylphthalimide, N-vinylformamide, N-vinylacetamide, N-methyl-N-vinylformamide, N-methyl-N-vinylacetamide, N-methyl-N-vinylacetamide Similar. Among these monofunctional N-vinyl compound monomers, N-vinyl-2-caprolactam is highly photocurable and can improve the fixability of ink to a surface of a transfer sheet more preferably.
    [0151] (c) Polyfunctional vinyl ether-based monomer
    [0153] A polyfunctional vinyl ether-based monomer is a compound that contains at least two vinyl ether groups in a molecule. Herein, the "vinyl ether group" is refers to -0-CH = CHR1 (in which R1 is a hydrogen atom or an organic group). The incorporation of a polyfunctional vinyl ether-based monomer can provide a photocurable monomer component that light cures rapidly when UV irradiated and is highly photocurable. Furthermore, among the monomers that are highly photocurable, the polyfunctional vinyl ether-based monomer has the characteristic of being low in stiffness (high in flexibility) after curing. Therefore, the ink for inkjet disclosed herein includes a polyfunctional vinyl ether-based monomer in a weight ratio of 2% by mass or more to 100% by mass as the total weight of the photocurable monomer component, so that it is sufficiently photocurable with certainty while suppressing a decrease in flexibility after photocuring. From the viewpoint of offering even better photocurability, the weight ratio of the polyfunctional vinyl ether-based monomer is preferably 5% by mass or more, more preferably 7% by mass or more, even more preferably 10% by mass. or more and especially preferably 15% by mass or more.
    [0155] Meanwhile, in the case that only attention is paid to flexibility after curing, the monofunctional acrylate-based monomer described above is better than the polyfunctional vinyl ether-based monomer. Therefore, if the content of the polyfunctional vinyl ether-based monomer is too high and the content of the monofunctional acrylate-based monomer is low, the flexibility after curing may be insufficient and cracks may occur. From this point of view, the weight ratio of the polyfunctional vinyl ether-based monomer in the inkjet ink described herein is set to 40% by mass or less. From the viewpoint of preventing the occurrence of cracks after curing more accurately, the weight ratio of the polyfunctional vinyl ether-based monomer is preferably 35% by mass or less, more preferably 30% by mass or less, still more preferably 25% by mass or less and especially preferably 20% by mass or less.
    [0157] Preferred examples of the polyfunctional vinyl ether-based monomer include etilenglicoldiviniléter, dietilenglicoldivinileter, trietilenglicoliviniléter, tetraetilenglicoliviniléter, polietilenglicoldivinileter, propilenglicoldivinileter, dipropilenglicoliviniléter, tripropilenglicoliviniléter, polipropilenglicoliviniléter, butanodioldiviniléter, neopentilglicoliviniléter, hexanodioldiviniléter, nonanodioldiviniléter, 1,4-cyclohexanedimethanolivinylether and the like. Among these, diethylene glycol vinyl ether, triethylene glycol vinyl ether, and 1,4-cyclohexanedimethaneol vinyl ether can have high fixing ability to the surface of a substrate and high flexibility after curing and are therefore especially preferred.
    [0159] (d) Other monomers
    [0161] The photocurable monomer component of the inkjet ink disclosed herein may include monomers other than the monomers (a) to (c) described above (other monomers) as long as the effect of the present invention is not significantly impaired.
    [0163] An example of other monomers is a polyfunctional acrylate-based monomer that includes at least two acryloyl groups or methacryloyl groups in a molecule. Preferred examples of the polyfunctional acrylate-based monomer include 1,9-nonanodioldi (meth) acrylate, 1,6-hexanedioldi (meth) acrylate, 1,4-butanedioldi (meth) acrylate, tricyclodecanedimethaneoldiacrylate, hydroxy neopentylglycoldiacrylate (triethylene glycolic acid) meth) acrylate, tetraethylene glycol (meth) acrylate, tripropylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, 1,3-butanediol (meth) acrylate, neopentylglycoldi (meth) acrylate, hexanedioldi (meth) acrylate, 1,4-cyclo dimethanoldi (meth) acrylate, cyclohexane-1,3-dimethanoldi (meth) acrylate, 1,4-cyclohexanedioldi (meth) acrylate, tetraethylene glycol (meth) acrylate, pentaerythritoldi (meth) acrylate, dipentaerythritoldi (meth) acrylate, nentyloldi (meth) acrylate acrylate, polytetramethylene glycol (meth) acrylate, bisphenol AE03.8 mol diacrylate adduct, trimethylolpropanotri (meth) acrylate, trimethyloletanotri (meth) acrylate, trimethyloloctanetri (meth) acrylate, pentaerythritolri (meth) acrylate polyethopane, trimethylolpropanotri (meth) acrylate itritoltri (meth) acrylate, dipentaerythritoltri (meth) acrylate of propionic acid, tris (2-hydroxyethyl) isocyanuratotri (meth) acrylate, sorbitoltri (meth) acrylate, ditrimethylolpropantetra (meth) acrylate, pentaerythritolpolyethoxypropyl acrylate (meth) acrylationaryl polyethopolymer , sorbitoltetra (meth) acrylate, dipentaerythritoltetra (meth) acrylate propionic acid, pentaerythritoltetra (meth) acrylate ethoxylate, sorbitolpenta (meth) acrylate, dipentaerythritolpenta (meth) acrylate, dipentaerythritolhexato (meth) acrylate (sorbitol) acrylate (meth) acrylate (sorbitol) and the like.
    [0164] Some examples of other monomers other than the polyfunctional acrylate-based monomer include butylvinylether, butylpropenyl ether, butylbutenylether, hexylvinylether, ethylhexylvinylether, phenylvinylether, benzylvinylether, phenylalylether, vinyl acetate, acrylamide (methacrylamide, trimethylolpropanyl (methacrylamide), trimethylolpropanyl (methacrylamide), trimethylolpropanyl (methacrylamide) ) acryloyloxyethyl) isocyanurate, bisphenol A diglycidylether acrylic acid adduct and the like.
    [0166] From the viewpoint of causing the effect of the present invention to be exhibited preferentially, it may occasionally be preferred that the photocurable monomer component contains substantially none of the monomers other than monomers (a) to (c) (any of the others monomers). As used herein, the term "substantially does not contain" indicates that none of the other monomers are incorporated in order to provide a specific effect for said other monomer. Specifically, a case where a component that can be interpreted as the "other monomer" is inevitably contained due to the material, the production process or the like is encompassed by the concept of "does not contain substantially" in the sense of this specification. For example, in the case that the weight ratio of any of the other monomers described above is 1% by mass or less (preferably 0.1% by mass or less, more preferably 0.01% by mass or less, even more preferably 0.001% by mass or less and especially preferably 0.0001% by mass or less), it is interpreted that "another monomer is substantially not contained and the photocurable monomer component is made up of the monomers (a ) to (c) ".
    [0168] (3) Other components
    [0170] The inkjet ink disclosed herein may include a known additive usable for inkjet ink (typically inkjet ink for an inorganic substrate and photocurable inkjet ink) (eg, a diffuser, a photoinitiator , a polymerization inhibitor, a binder, a viscosity adjuster, etc.) provided that the effect of the present invention is not spoiled. The content of each of the aforementioned additives can be set appropriately for the purpose of incorporation and does not characterize the present invention and therefore will not be described in detail.
    [0171] (a) Diffuser
    [0173] The inkjet ink disclosed herein may include a diffuser. An example of a usable diffuser is a cation-based diffuser. Such a cation-based diffuser adheres to the surface of an inorganic pigment efficiently by acid-base reaction and thus can suppress the condensation of the inorganic pigment mentioned above and diffuse the inorganic pigment preferentially, unlike other diffusers. as is a diffuser based on phosphoric acid and the like. An example of a cation-based diffuser is an amine-based diffuser. An amine-based diffuser can prevent, through steric effects, condensation of the inorganic pigment and can stabilize the inorganic pigment. Furthermore, the amine-based diffuser can provide particles of the inorganic pigment with the same charge, and for this reason also, it can preferably prevent condensation of the inorganic pigment. Therefore, the amine-based diffuser can lower the viscosity of the ink preferably to significantly improve the printability of the ink. Some examples of an amine-based diffuser include a fatty acid amine-based diffuser, a polyester amine-based diffuser, and the like. For example, DISPERBYK-2013 produced by BYK-Chemie Japan Kabushiki Kaisha, or the like, is preferably usable.
    [0175] (b) Photoinitiator
    [0177] The inkjet ink disclosed herein may include a photoinitiator. As the photoinitiator, any conventionally used photoinitiator can be appropriately selected. Some examples of a photoinitiator include radical-based photoinitiators such as an alkylphenone-based photoinitiator, an acylphosphine oxide-based photoinitiator, and the like. Preferably usable examples of the alkylphenone-based photoinitiator include photoinitiators based on α-aminoalkylphenone (e.g., 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (dimethylamino) -2 - [(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone and the like). Other usable examples of the alkylphenone-based photoinitiator include photoinitiators based on α-hydroxyalkylphenone (1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- [4- ( 2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl } -2-methyl-propan-1-one and Similar).
    [0179] Among the various photoinitiators listed above, a-aminoalkylphenone-based photoinitiators like 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one and the like can exhibit high reactivity to increase ink curing speed and have high thin film curing ability and surface curability and are therefore especially preferably usable.
    [0181] (c) Polymerization inhibitor
    [0183] The inkjet ink disclosed herein may include a polymerization inhibitor. Incorporation of the polymerization inhibitor can prevent the photocurable monomer component from polymerizing and curing before the photocurable monomer component is used, and thus allows the ink to be easily stored. As the polymerization inhibitor, any polymerization inhibitor conventionally used in the field of photocurable inkjet ink can be used without specific limitation as long as the photocurability of the photocurable monomer component including monomers (a) to (c) does not decrease significantly. Some examples of a polymerization inhibitor include hydroquinone, methoquinone, di-t-butylhydroquinone, P-methoxyphenol, butylhydroxytoluene, nitroamine salt, and the like. Among the compounds contained therein, the N-nitrophenylhydroxylamine aluminum salt is highly stable during long storage and is therefore especially preferred.
    [0185] 2. Preparing the ink for inkjet
    [0187] Now, a preparation (production) method of the ink for inkjet ink disclosed herein will be described. The inkjet ink disclosed herein can be prepared by mixing the above-described materials in a predetermined ratio and then grinding and diffusing the inorganic solids content. FIGURE 1 is a cross-sectional view schematically showing a stirring and spraying device usable for producing the ink for inkjet. The following description is not intended to limit the inkjet ink disclosed herein.
    [0188] To produce the jet ink disclosed herein, first, the materials described above are weighed and mixed to prepare a suspension, which is a precursor to the ink.
    [0190] Next, a stirring and spraying device 100 as shown in FIGURE 1 is used to stir the suspension and pulverize the inorganic solid content (inorganic pigment and glass). Specifically, spray beads (eg, zirconium beads having a diameter of 0.5 mm) are incorporated into the aforementioned suspension and then the suspension is supplied to a stirring vessel 120 from a supply port 110. Stirring vessel 120 houses a shaft 134 having a plurality of stirring paddles 132. One end of shaft 134 is attached to a motor (not shown). The motor is driven to rotate the shaft 134 so that the suspension is stirred while subsequently being supplied with respect to a liquid supply direction A by the plurality of stirring blades 132. During stirring, the inorganic solid content is pulverized by the spray beads incorporated into the suspension and the inorganic solid content in the form of microscopic particles diffuses into the suspension.
    [0192] The suspension reaching the back side with respect to the liquid supply direction A passes through a filter 140. As a result, the spray beads and a part of the inorganic solid content that was not formed in the microscopic particles are collected by the filter 140 and inkjet ink in which the microscopic particulate inorganic solid content is sufficiently diffused is discharged from a discharge port 150. The diameters of the pores of the filter 140 can be adjusted to control the maximum particle diameter of the inorganic solid content in the inkjet ink.
    [0194] 3. Production method of transfer sheet (printing method)
    [0196] Now, a method for producing a transfer sheet for an inorganic substrate using the inkjet ink disclosed herein (printing method for drawing an image on a surface of the transfer sheet) will be described.
    [0198] FIGURE 2 is a general view schematically showing an example of inkjet device. FIGURE 3 is a cross-sectional view schematically showing an ink jet head in the ink jet device in FIGURE 2.
    [0200] The ink jet ink disclosed herein is stored in ink jet heads 10 in an ink jet device 1 shown in FIGURE 2. The ink jet device 1 includes four ink jet heads 10. The ink jet heads 10 store, respectively, ink of four different colors of black (K), cyan (C), yellow (Y) and magenta (M). The ink jet heads 10 are housed in a print cartridge 40. The print cartridge 40 is inserted on a guide axis 20, and is structured to reciprocate along an axial direction X of the guide axis 20. Although not shown, the inkjet device 1 includes a movement mechanism that moves the guide axis 20 in a vertical direction Y. With such a structure, ink can be ejected from the inkjet heads 10 to a desired position. on a base sheet W of the transfer sheet.
    [0202] The inkjet heads 10 shown in FIGURE 2 are each, for example, a piezoelectric type inkjet head as shown in FIGURE 3. The piezoelectric type inkjet head 10 includes a portion 13 storage, which stores the ink, provided in a box 12. The storage part 13 is in communication with an ejection part 16 through a liquid supply path 15. The ejection part 16 is provided with an ejection opening 17 open towards the outside of the box 12 and is also provided with a piezoelectric element 18 positioned so as to face the ejection opening 17. In the ink jet head 10, the piezoelectric element 18 is vibrated to eject the ink in the ejection portion 16 towards the base sheet W (see FIGURE 2) from the ejection opening 17.
    [0204] The guide shaft 20 in the ink jet device 1 shown in FIGURE 2 is provided with a UV radiation part 30. The UV radiation portion 30 is located adjacent to the print cartridge 40 and moves in conjunction with the reciprocal movement of the print cartridge 40 to radiate ultraviolet rays towards the base sheet W having the ink adhered thereto. With such an arrangement, the ink cures immediately after adhering to the base sheet W. Therefore, even if a fixing layer as is a porous fixing layer or the like on a surface of the base sheet W, the ink can be fixed with a sufficient thickness on the surface of the transfer sheet (base sheet W).
    [0206] The transfer sheet for an inorganic substrate produced in the process described above includes the base sheet W and an image part including a cured body of the inkjet ink. As described above, the inkjet ink described herein comprises a photocurable monomer component that is sufficiently flexible after curing. Therefore, the image part can be prevented from cracking when the transfer sheet is curved.
    [0208] 4. Method of producing an inorganic article
    [0210] The transfer sheet described above is used to produce an inorganic article that includes a decorative part. The method for producing the inorganic article includes a step of gluing the transfer sheet to the inorganic substrate and a step of baking the inorganic substrate.
    [0212] There is no specific limitation on the type of inorganic substrate, such as a decoration target performed by the technology disclosed herein, as long as the effect of the present invention is exhibited. Any general inorganic substrate can be used without specific limitation. Some examples of the inorganic substrate include ceramic substrates such as ceramic and porcelain articles, ceramic tiles, and the like; glass substrates; metal substrates; and the like. There is no specific limitation on the form of the inorganic substrate. A substrate in any desired shape can be used. As described above, the transfer sheet produced by using the ink jet ink disclosed herein includes the image portion that is sufficiently flexible. Thus, the image (cured ink) is prevented from cracking when the transfer sheet is curved according to the shape of the inorganic substrate. Therefore, the production method disclosed herein is especially preferably usable to produce an inorganic substrate for which the transfer sheet needs to be curved (typically, an inorganic substrate having a curved surface, a convex part and a concave , etc.).
    [0213] As described above, in accordance with the production method disclosed herein, the transfer sheet is glued to the surface of the inorganic substrate. There is no specific limitation on the method of gluing the transfer sheet to the inorganic substrate. Any known method can be used without specific limitation. For example, a water soluble pressure adhesive layer can be formed on the surface of the base sheet and the pressure adhesive layer can be moistened, such that the transfer sheet preferably sticks to the surface of the inorganic substrate. Even in the case that such a water-soluble pressure adhesive layer is formed on the surface of the base sheet, the ink jet ink disclosed herein can be fixed to the surface of the printing target preferably.
    [0215] According to the production method disclosed herein, below, the inorganic substrate having the transfer sheet attached thereto is fired in a condition in which a higher firing temperature is set at a temperature in the range 500 ° C to 1200 ° C (preferably 500 ° C to 1000 ° C and more preferably 600 ° C to 900 ° C). As a result, the base sheet of the transfer sheet and a resin component including the cured monomer burn out and the glass in the inorganic solid content melts. The inorganic substrate is cooled after firing so that the molten glass solidifies and the inorganic pigment binds to the surface of the substrate. As a result, the image drawn on the transfer sheet is transferred to the inorganic substrate and the inorganic article including a desired decorative part (image) is produced.
    [0217] [Test examples]
    [0218] Hereinafter, a test example according to the present invention will be described. The test examples are not intended to limit the present invention.
    [0220] <Inkjet ink>
    [0221] 29 types of inkjet ink were prepared (Examples 1 to 29), each comprising an inorganic solids content and a photocurable monomer component. Specifically, a suspension of mixed materials was prepared in a mass ratio shown in Table 1 to Table 3 and They used spray beads (zirconia beads having a diameter of 0.5mm) to perform a spray and diffusion process. As a result, the ink of Examples 1 to 29 was obtained. The mass ratios in the tables are values with respect to 100% by mass as the total weight of the ink, unless otherwise specified. In the test examples, 13.6% by mass of diffuser (DISPERBYK-2013 produced by BYK-Chemie Japan Kabushiki Kaisha), 1.6% by mass of photoinitiator (Omnirad 819 produced by IGM RESINS) and 0, 2 mass% polymerization inhibitor (Q-1301 produced by FUJIFILM Wako Puré Chemical Corporation (N-nitroso-N-phenylhydroxylamine aluminum)) was incorporated in addition to the inorganic solid content and the photocurable monomer.
    [0223] With respect to the content of inorganic solids used in the test examples, "yellow" in Tables 1 to 3 is a yellow inorganic pigment based on zirconium (zirconiopraseodymium). "Cyan" is an inorganic cyan pigment based on zirconium (zirconiumvanadium). "Black" is a spinel-based black inorganic pigment (spinel black). "Glass" is borosilicate glass that has a softening point of 550 ° C.
    [0225] Regarding the monofunctional acrylate-based monomer used in the test examples, "BZA" in the tables is benzylacrylate (produced by Osaka Organic Chemical Industry Ltd.). "PHEA" is phenoxyethylacrylate (produced by Osaka Organic Chemical Industry Ltd.). "CTFA" is cyclic trimethylolpropane formacrylate (produced by Osaka Organic Chemical Industry Ltd.). With respect to monofunctional N-vinyl compound monomer (monofunctional vinyl ether-based monomer), "NVC" is N-vinylcaprolactam (produced by Tokyo Chemical Industry Co., Ltd.). With respect to the polyfunctional N-vinyl compound monomer (polyfunctional vinyl ether-based monomer), "TEGDVE" is triethylene glycol vinyl ether (produced by Nippon Carbide Industries Co., Inc.). "DEGDVE" is dimethylene glycoldivinylether produced by Nippon Carbide Industries Co., Inc. "CHDVE" is 1,4-cyclohexanedimethaneoldivinylether (produced by Nippon Carbide Industries Co., Inc). In Examples 28 and 29, a monofunctional vinyl ether-based monomer (EHVE: 2-ethylhexylvinylether, produced by Nippon Carbide Industries Co., Inc.) was used in place of the polyfunctional vinyl ether-based monomer.
    [0226] <Assessment tests>
    [0228] (1) Production of the transfer sheet
    [0229] The ink in each of the above-mentioned examples was ejected onto a surface of a base sheet (produced by Marushige Shiko Co., Ltd.) that includes an applied layer of water-soluble adhesive material through the use of an inkjet device. ink (Material Printer (DMP-2831) produced by FUJIFILM Corporation). The ink adhered to the surface of the base sheet was UV irradiated, so that a transfer sheet was produced, for an inorganic substrate, having a cured body of thickness 50 to 100 p, m of the ink (image) formed. about him.
    [0231] (2) Evaluation of photocurability
    [0232] The surface of the produced transfer sheet was wiped with waste paper and the surface of the waste paper was visually observed. A case where the waste paper did not have uncured ink adhered thereto was evaluated as having a preferred (acceptable) photocurability. On the contrary, a case where the waste paper had ink adhered to it was evaluated as having insufficient (unacceptable) curability. The results of the evaluation are shown in Tables 1a3.
    [0234] (3) Flexural strength
    [0235] The transfer sheet was folded so that an image-forming surface was folded into a mountain shape, and it was visually observed whether or not the folded part was bleached, cracked or the like. A case in which the external appearance was not modified, eg, no whitening or cracking occurred, was evaluated as having sufficient flexural strength (sufficient flexibility) (acceptable). A case where whitening or cracking occurred was evaluated as having insufficient flexural strength (insufficient flexibility) (unacceptable). The results of the evaluation are shown in Tables 1a3.
    [0237] (3) Rub resistance
    [0238] The surface of the transfer sheet was rubbed with waste paper and it was visually observed whether or not the image peeled off or exfoliated. A case in which the external appearance of the film was not modified was evaluated with sufficient (acceptable) rub resistance. A case in which the image peeled off or peeled off was evaluated as having insufficient rub resistance (unacceptable). The results of the evaluation are shown in Tables 1a3.
    [0239]
    [0240]
    [0241]
    [0242] As shown in Tables 1 to 3, in Examples 1 to 15, preferred results were obtained in all of light curing, flexural strength and rub resistance. From this, it has been confirmed that the use of a photocurable monomer component formed by mixing a monofunctional acrylate-based monomer, a monofunctional N-vinyl compound monomer, and a polyfunctional vinyl ether-based monomer in a predetermined ratio can provide both a high photocurable as high flexibility.
    [0244] Until now, specific examples of the present invention have been described. These examples are merely illustrative and do not limit the scope of the claims in any way. The technology within the scope of the claims encompasses various alterations and modifications of the specific examples described above. List of reference signs
    [0245] 1 Inkjet device
    [0246] 10 Inkjet head
    [0247] 12 Box
    [0248] 13 Storage part
    [0249] 15 Liquid supply path
    [0250] 16 Part of expulsion
    [0251] 17 Ejection opening
    [0252] 18 Piezoelectric element
    [0253] 20 Guide shaft
    [0254] 30 Part UV radiation
    [0255] 40 Print cartridge
    [0256] 100 Stirring and spraying device
    [0257] 110 Supply opening
    [0258] 120 Stirring vessel
    [0259] 132 Stirring paddle
    [0260] 134 Axle
    [0261] 140 Filter
    [0262] 150 Discharge opening
    [0263] A Liquid supply direction
    [0264] X Axial direction of guide shaft
    [0265] Y Vertical direction with respect to the guide axis
    权利要求:
    Claims (8)
    [1]
    1. Usable inkjet ink for a transfer sheet suitable for an inorganic substrate, the inkjet ink comprising:
    an inorganic solid content that includes an inorganic pigment and glass; and a monomer component that has light curability,
    where:
    the monomer component includes at least:
    a monofunctional acrylate-based monomer containing an acryloyl group or a methacryloyl group in a molecule;
    a monofunctional N-vinyl compound monomer containing a nitrogen-containing compound and a vinyl group attached to a nitrogen atom (N) of the nitrogen-containing compound; and
    a polyfunctional vinyl ether-based monomer containing at least two vinyl ether groups in one molecule,
    the monofunctional acrylate-based monomer is contained in a weight ratio of 40% by mass to 96% by mass with respect to 100% by mass as the total weight of the monomeric component,
    the monofunctional N-vinyl compound monomer is contained in a weight ratio of 2% by mass to 20% by mass with respect to 100% by mass as the total weight of the monomer component and
    the polyfunctional vinyl ether-based monomer is contained in a weight ratio of 2% by mass to 40% by mass relative to 100% by mass as the total weight of the monomer component.
    [2]
    The inkjet ink of claim 1, wherein the monofunctional acrylate-based monomer contains at least one selected from the group consisting of benzylacrylate, phenoxyethylacrylate, and cyclic trimethylolpropane-formalacrylate.
    [3]
    3. The inkjet ink according to claim 1 or 2, wherein the monofunctional N-vinyl compound monomer is N-vinyl-2-caprolactam.
    [4]
    The inkjet ink according to any one of claims 1 to 3, wherein the polyfunctional vinyl ether-based monomer contains at least one selected from the group consisting of diethylene glycol vinyl ether, triethylene glycoldivinylether and 1,4-cyclohexanedimethaneoldivinylether.
    [5]
    The ink for inkjet according to any one of claims 1 to 4, wherein the inorganic solid content is contained in a weight ratio of 20% by mass to 50% by mass relative to 100% by mass as the total weight of the inkjet ink.
    [6]
    6. A method of producing a transfer sheet for an inorganic substrate to be fired, the method comprising:
    a step of adhering the ink jet ink according to any one of claims 1 to 5 to a surface of a base sheet using an ink jet device; and
    a step of curing the inkjet ink adhering to the surface of the base sheet by irradiating with ultraviolet rays to the surface of the base sheet.
    [7]
    7. A transfer sheet suitable for an inorganic substrate to be fired, the transfer sheet comprising:
    a base sheet; and
    an image part including a cured inkjet ink body according to any one of claims 1 to 5.
    [8]
    8. A method for producing an inorganic article including a decorative part, the method comprising:
    a step of gluing the transfer sheet according to claim 7 to a surface of an inorganic substrate; and
    a cooking step of the inorganic substrate under a condition that the highest cooking temperature is set at a temperature in the range of 500 ° C to 1200 ° C.
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    同族专利:
    公开号 | 公开日
    CN113490599A|2021-10-08|
    JPWO2020174869A1|2020-09-03|
    WO2020174869A1|2020-09-03|
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    法律状态:
    2021-09-30| BA2A| Patent application published|Ref document number: 2858516 Country of ref document: ES Kind code of ref document: A2 Effective date: 20210930 |
    优先权:
    申请号 | 申请日 | 专利标题
    JP2019034699|2019-02-27|
    PCT/JP2019/051397|WO2020174869A1|2019-02-27|2019-12-27|Inkjet ink|
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