Sheet for inkjet printing

Abstract

The present invention addresses the problem of providing a sheet for inkjet printing, which is capable of ensuring sufficient printing density while suppressing printing unevenness by suppressing variation in the interference among dots in the surface of an ink-receiving layer. The present invention has solved this problem by a sheet for inkjet printing, said sheet having a multilayer structure that comprises an ink-receiving layer, a base material, an adhesive layer, and a release liner in this order, the release liner having a silicone-based release agent layer in a contact surface that is in contact with the adhesive layer, the ink-receiving layer being a cured layer of an ink-receiving layer forming composition that contains a specific energy ray curable compound (A) and a silicone-based leveling agent (B), and the water contact angle of the ink-receiving layer being 80° or less.

Description

Inkjet printing sheets

[0001] The present invention relates to a sheet for inkjet printing.

[0002] Inkjet recording is a method of recording by ejecting ink droplets and depositing the ink onto an inkjet printing medium to form dots. Inkjet recording is rapidly gaining popularity due to its advantages, such as the ease with which high-quality full-color images can be obtained, its ease of high speed, and its low running costs. Furthermore, with the spread of inkjet recording, various inkjet printing media have also been proposed. For example, an inkjet printing sheet has been proposed that has a layered structure including, in this order, an ink-receiving layer, a substrate, an adhesive layer, and a release liner, and that can be attached to glass or the like to be used as indoor or outdoor decoration.

[0003] In this specification, the term "ink receiving layer" refers to a layer to which ink for inkjet printing is applied and which has the function of fixing the printed portion of the applied ink for inkjet printing.

[0004] In recent years, various ink-receiving layers have been proposed, including, for example, an ink-receiving layer containing a vinyl chloride resin and a vinyl acetate resin (see Patent Document 1, etc.), an ink-receiving layer containing polyvinyl butyral (see Patent Document 2, etc.), and the like.

[0005] JP 2019-172877 A JP 2007-130776 A

[0006] The present inventors encountered the problem of print unevenness during research and development on ink-receiving layers. Specifically, when ink droplets are ejected onto an ink-receiving layer using an inkjet recording method to form dots, the dots may not interfere properly with each other in some areas of the ink-receiving layer, resulting in uneven interference between the dots within the ink-receiving layer. This causes the print in those areas to appear lighter than normal, resulting in visible print unevenness when the entire printed area formed on the ink-receiving layer is observed. After extensive research to resolve this problem, the present inventors discovered that attempts to eliminate the print unevenness result in a decrease in print density throughout the entire printed area formed on the ink-receiving layer. Thus, it has been difficult to simultaneously suppress print unevenness and ensure print density in the ink-receiving layer.

[0007] The present invention has been made in consideration of such problems, and its objective is to provide an inkjet printing sheet that can suppress variations in interference between dots within the ink-receiving layer surface, thereby suppressing printing unevenness, while still ensuring sufficient printing density.

[0008] As a result of extensive research into solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by (1) making the ink-receiving layer a cured layer of a composition for forming an ink-receiving layer that contains a specific energy ray-curable compound and a silicone-based leveling agent, and (2) setting the water contact angle of the ink-receiving layer to 80° or less.

[0009] That is, the present invention relates to the following [1] to [7]. [1] A sheet for inkjet printing having a laminated structure including, in this order, an ink-receiving layer, a substrate, a pressure-sensitive adhesive layer, and a release liner, wherein the release liner has a silicone-based release agent layer on the surface that contacts the pressure-sensitive adhesive layer, the ink-receiving layer being a cured layer of an ink-receiving layer-forming composition containing an energy ray-curable compound (A) and a silicone-based leveling agent (B), the energy ray-curable compound (A) being an ester of a polyol compound and (meth)acrylic acid, and the ink-receiving layer having a water contact angle of 80° or less. [2] The sheet for inkjet printing according to [1] above, wherein the energy ray-curable compound (A) further satisfies one or more of the following requirements (X1) to (X3): Requirement (X1): The ester is a partial ester. Requirement (X2): The polyol compound constituting the ester is an alkylene oxide modified product. However, the alkylene group constituting the alkylene oxide modified product has 2 to 4 carbon atoms. Requirement (X3): The polyol compound constituting the ester has a glycerin skeleton. [3] The inkjet printing sheet according to [1] or [2] above, wherein the ink-receiving layer-forming composition further contains a filler (C). [4] The inkjet printing sheet according to any one of [1] to [3] above, which is in the form of a rolled body or a wound body wound around a core material. [5] A method of use, comprising using the inkjet printing sheet according to any one of [1] to [4] above to form a printed section on the ink-receiving layer of the inkjet printing sheet using an inkjet printing ink. [6] A method of producing a printed matter, comprising the step of forming a printed section on the ink-receiving layer of the inkjet printing sheet according to any one of [1] to [4] above, using an inkjet printing ink. [7] A printed matter having a printed portion printed with ink for inkjet printing on the ink-receiving layer of the ink-jet printing sheet according to any one of [1] to [4] above.

[0010] According to the present invention, it is possible to provide an inkjet printing sheet that can suppress variations in interference between dots within the ink-receiving layer surface, thereby suppressing printing unevenness, while still ensuring sufficient printing density.

[0011] 1 is a schematic cross-sectional view showing an example of an inkjet printing sheet according to one embodiment of the present invention, and is a schematic cross-sectional view showing a stacked state of two inkjet printing sheets in a pretreatment carried out before evaluations (2) and (3) in the examples.

[0012] As used herein, the term "active ingredient (solid content)" refers to the components contained in the target composition, excluding diluting solvents such as water and organic solvents. In this specification, (meth)acrylate refers to both methacrylate and acrylate, and the same applies to other similar terms. For example, (meth)acrylic acid refers to both methacrylic acid and acrylic acid, and (meth)acryloyl group refers to both methacryloyl and acryloyl groups. In this specification, the lower and upper limits of preferred numerical ranges (e.g., ranges of content, etc.) described in stages can be independently combined. For example, the description "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferred upper limit (60)" to form "10 to 60." In this specification, the numerical values ​​in the examples are values ​​that can be used as upper or lower limits.

[0013] [Embodiments of the Inkjet Printing Sheet of the Present Invention] The inkjet printing sheet of the present invention has a laminated structure including, in this order, an ink-receiving layer, a substrate, a pressure-sensitive adhesive layer, and a release liner. The release liner has a silicone-based release agent layer on the surface that contacts the pressure-sensitive adhesive layer. The ink-receiving layer is a cured layer of an ink-receiving layer-forming composition that contains an energy ray-curable compound (A) and a silicone-based leveling agent (B). The energy ray-curable compound (A) is an ester of a polyol compound and (meth)acrylic acid. The water contact angle of the ink-receiving layer is 80° or less.

[0014] The present inventors conducted extensive research to solve the above-mentioned problems. As a result, they discovered that by incorporating a silicone-based leveling agent into an ink-receiving layer, it is possible to suppress variations in interference between dots within the surface of the ink-receiving layer and thereby suppress print unevenness. However, they found that suppressing print unevenness by incorporating a silicone-based leveling agent into the ink-receiving layer reduces the print density of the entire printed area formed on the ink-receiving layer. To solve this problem, the present inventors conducted further extensive research. As a result, they discovered that by forming the ink-receiving layer as a cured layer of an ink-receiving layer-forming composition containing the above-mentioned specific energy ray-curable compound (A) and silicone-based leveling agent (B), and by adjusting the water contact angle of the ink-receiving layer to 80° or less, it is possible to ensure sufficient print density while suppressing print unevenness.

[0015] Although the mechanism by which the effects of the present invention are achieved is not clear, it is speculated as follows. Specifically, by forming an inkjet printing sheet having the above-described laminated structure into a rolled body or a wound body wrapped around a core, minute amounts of silicone components migrate to the surface of the ink-receiving layer when the ink-receiving layer comes into contact with the back surface of the release liner. As a result, local variations in surface free energy occur on the surface of the ink-receiving layer. In areas where local variations in surface free energy occur, the wettability of dots to the ink-receiving layer decreases compared to areas where no variations in surface free energy occur, resulting in less interference between dots than usual. This phenomenon inhibits the proper interference between dots that should occur, resulting in a pale printed area. It is speculated that the pale printed area appears in areas where surface energy variations occur, while the standard dark area appears in areas where no variations in surface free energy occur, resulting in visible print unevenness. Furthermore, the print unevenness is suppressed by suppressing the variation in interference between dots within the ink-receiving layer surface by incorporating a silicone-based leveling agent into the ink-receiving layer. The effect of suppressing print unevenness is presumably achieved by incorporating a silicone-based leveling agent into the ink-receiving layer, which prevents regions with an excessive silicone component from being mixed with regions with no silicone component at all within the ink-receiving layer surface. In other words, the print unevenness suppression effect is presumably achieved by homogenizing the surface free energy within the ink-receiving layer surface. On the other hand, incorporating a silicone-based leveling agent into the ink-receiving layer reduces the wettability of the entire ink-receiving layer, making it difficult for dots to wet and spread across the entire ink-receiving layer. As a result, the print density of the entire printed area formed on the ink-receiving layer decreases. Therefore, the ink-receiving layer is formed as a cured layer of a composition for forming an ink-receiving layer containing the specific energy ray-curable compound (A) and silicone-based leveling agent (B), and the water contact angle of the ink-receiving layer is adjusted to 80° or less, thereby improving the wettability of the entire ink-receiving layer, making it easier for the dots to wet and spread, ensuring sufficient print density while also fully suppressing print unevenness.

[0016] The inkjet printing sheet of the present invention will be described in detail below with respect to its configuration, the ink-receiving layer, substrate, adhesive layer, and release liner that constitute the inkjet printing sheet, the method for producing the inkjet printing sheet, and uses of the inkjet printing sheet.

[0017] [Configuration of Inkjet Printing Sheet] The inkjet printing sheet of the present invention has a laminated structure including, in this order, an ink-receiving layer, a substrate, a pressure-sensitive adhesive layer, and a release liner. FIG. 1 shows a schematic cross-sectional view of one embodiment of the inkjet printing sheet of the present invention. The inkjet printing sheet 1 shown in FIG. 1 has a laminated structure including, in this order, an ink-receiving layer 2, a substrate 3, a pressure-sensitive adhesive layer 4, and a release liner 5. The release liner 5 has a silicone-based release agent layer 5a and a support 5b, with the silicone-based release agent layer 5a in contact with the pressure-sensitive adhesive layer 4. In the inkjet printing sheet 1 shown in FIG. 1, the ink-receiving layer 2, the substrate 3, the pressure-sensitive adhesive layer 4, and the release liner 5 are laminated directly together without any intervening layers. Therefore, the inkjet printing sheet 1 shown in FIG. 1 is composed only of the ink-receiving layer 2, the substrate 3, the pressure-sensitive adhesive layer 4, and the release liner 5. However, the inkjet printing sheet 1 is not necessarily limited to this configuration. For example, another layer may be provided, if necessary, between the ink-receiving layer 2 and the substrate 3 or between the substrate 3 and the pressure-sensitive adhesive layer 4. An example of such another layer is an easy-adhesion layer. Furthermore, the silicone-based release agent layer 5a and the support 5b may be directly laminated together as shown in Figure 1, but another layer may be provided, if necessary, between the silicone-based release agent layer 5a and the support 5b. An example of such another layer is a sealing layer.

[0018] <Ink-receiving layer> In the inkjet printing sheet of the present invention, the ink-receiving layer is a cured layer of an ink-receiving-layer-forming composition containing an energy ray-curable compound (A) and a silicone-based leveling agent (B), and has a water contact angle of 80° or less. This configuration makes it possible to suppress variations in interference between dots within the ink-receiving layer surface, thereby suppressing printing unevenness, while ensuring sufficient print density.

[0019] (Water contact angle of ink-receiving layer) In the present invention, the water contact angle of the ink-receiving layer must be 80° or less. If the water contact angle of the ink-receiving layer is 81° or more, the wettability of the ink-receiving layer cannot be sufficiently ensured, making it difficult for the dots to wet and spread, resulting in a decrease in print density. From the viewpoint of making it easier to ensure a sufficient print density, the water contact angle of the ink-receiving layer is preferably 79° or less, and more preferably 78° or less. There is no particular restriction on the lower limit of the water contact angle of the ink-receiving layer, but taking into consideration the configuration of the ink-receiving layer, it is usually 58° or more, for example.

[0020] In this specification, the water contact angle of the ink-receiving layer refers to a value measured by the method described in the Examples below. The portion of the ink-receiving layer where the water contact angle is measured is the portion where the ink for inkjet printing is applied.

[0021] The water contact angle of the ink-receiving layer can be adjusted by adjusting the type and content, etc., of the energy ray-curable compound (A) and the silicone-based leveling agent (B) contained in the composition for forming the ink-receiving layer. Hereinafter, the energy ray-curable compound (A), the silicone-based leveling agent (B), etc. will be described in detail, taking into account the method for adjusting the water contact angle of the ink-receiving layer.

[0022] (Energy ray-curable compound (A)) In the present invention, the composition for forming the ink-receiving layer contains an energy ray-curable compound (A). If the composition for forming the ink-receiving layer does not contain the energy ray-curable compound (A), it becomes difficult to adjust the water contact angle of the ink-receiving layer to 80° or less, and it becomes difficult to ensure sufficient print density. In addition, it becomes easy to increase the surface hardness of the ink-receiving layer, and it becomes easy to suppress scratches during application or use. Here, "energy ray-curable compound" means a compound that is cured (polymerized) by irradiation with energy rays. Therefore, the ink-receiving layer contains a polymer (resin) derived from the energy ray-curable compound (A). In addition, "energy rays" means electromagnetic waves or charged particle beams that have an energy quantum, and examples of such rays include ultraviolet rays and electron beams, with ultraviolet rays being preferred.

[0023] In the present invention, the energy ray-curable compound (A) is an ester of a polyol compound and (meth)acrylic acid. If the energy ray-curable compound (A) is a compound other than the ester of a polyol compound and (meth)acrylic acid, it becomes difficult to adjust the water contact angle of the ink-receiving layer to 80° or less, and it becomes difficult to ensure sufficient print density. The energy ray-curable compound (A) may be used alone or in combination of two or more.

[0024] The energy ray-curable compound (A) may be a polymerizable compound having one or more (meth)acryloyl groups in one molecule. From the viewpoint of further improving the effects of the present invention, the energy ray-curable compound (A) preferably has two or more (meth)acryloyl groups in one molecule, and more preferably has 2 to 6 (meth)acryloyl groups in one molecule.

[0025] The polyol compound constituting the energy ray-curable compound (A) is preferably a dihydric to decahydric polyol, more preferably a trihydric to hexahydric polyol. The polyol compound may also be an alkylene oxide-modified product. Therefore, alkylene oxide-modified products of dihydric to decahydric polyols, and more preferably alkylene oxide-modified products of trihydric to hexahydric polyols, are also examples of polyol compounds. The alkylene group constituting the alkylene oxide-modified product preferably has 2 to 4 carbon atoms, more preferably 2 to 3 carbon atoms, and even more preferably 2 carbon atoms.

[0026] Specific examples of preferred polyol compounds include polyols such as trimethylolethane, trimethylolpropane, trimethylolbutane, ditrimethylolpropane, tritrimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, polyglycerin (a glycerin polymer, preferably a dimer to decamer of glycerin, more preferably a dimer to hexamer of glycerin, and even more preferably a trimer to pentamer of glycerin), 1,3,5-pentanetriol, sorbitol, adonitol, arabitol, xylitol, and mannitol; and alkylene oxide modified products (preferably ethylene oxide modified products) of these polyols.

[0027] Here, from the viewpoint of making it easier to adjust the water contact angle of the ink-receiving layer to 80° or less, it is preferable that the energy ray-curable compound (A) satisfy one or more of the following requirements (X1) to (X3): Requirement (X1): The ester is a partial ester. Requirement (X2): The polyol compound constituting the ester is an alkylene oxide modified product, provided that the alkylene group constituting the alkylene oxide modified product has 2 to 4 carbon atoms. Requirement (X3): The polyol compound constituting the ester has a glycerin skeleton.

[0028] Esters of polyol compounds and (meth)acrylic acid that satisfy the above requirement (X1) tend to have a high hydroxyl value and high hydrophilicity, making it easy to adjust the water contact angle of the ink-receiving layer to 80° or less. From the viewpoint of further enhancing hydrophilicity and making it easier to adjust the water contact angle of the ink-receiving layer to 80° or less, the partial esters of polyol compounds and (meth)acrylic acid preferably have a hydroxyl value of 50 mgKOH / g or more, more preferably 70 mgKOH / g or more, and even more preferably 80 mgKOH / g or more. In this specification, the hydroxyl value refers to a value measured in accordance with JIS K0070:1992.

[0029] Esters of polyol compounds and (meth)acrylic acid that satisfy the above requirement (X2) tend to be highly hydrophilic, making it easy to adjust the water contact angle of the ink-receiving layer to 80° or less. The ester that satisfies the above requirement (X2) may be a complete ester or a partial ester. When the ester that satisfies the above requirement (X2) is a partial ester, it also satisfies the above requirement (X1). The alkylene group constituting the alkylene oxide modified product preferably has 2 to 4 carbon atoms, more preferably 2 to 3 carbon atoms, and even more preferably 2 carbon atoms. The number of alkylene oxides (molar number) per molecule is not limited, but is preferably 4.0 or more, more preferably 5 or more, and even more preferably 6 or more, from the viewpoint of increasing the hydrophilicity of the ester of polyol compounds and (meth)acrylic acid and making it easy to adjust the water contact angle of the ink-receiving layer to 80° or less.

[0030] Esters of polyol compounds and (meth)acrylic acid that satisfy the above requirement (X3) tend to be highly hydrophilic, making it easy to adjust the water contact angle of the ink-receiving layer to 80° or less. The ester that satisfies the above requirement (X3) may be a complete ester or a partial ester. When the ester that satisfies the above requirement (X3) is a partial ester, it also satisfies the above requirement (X1). The polyol compound having a glycerin skeleton refers to glycerin or polyglycerin. As mentioned above, polyglycerin refers to a glycerin polymer, preferably a dimer to decamer of glycerin, more preferably a dimer to hexamer of glycerin, even more preferably a trimer to pentamer of glycerin, and even more preferably a tetramer of glycerin.

[0031] In one embodiment of the present invention, the content of the energy ray-curable compound (A) is appropriately adjusted so that the water contact angle of the ink-receiving layer can be adjusted to 80° or less. Increasing the content of the energy ray-curable compound (A) in the composition for forming an ink-receiving layer reduces the water contact angle of the ink-receiving layer. Conversely, decreasing the content of the energy ray-curable compound (A) in the composition for forming an ink-receiving layer increases the water contact angle of the ink-receiving layer. In light of this tendency, the content of the energy ray-curable compound (A) is adjusted from the viewpoint of balancing with the amount of the silicone-based leveling agent (B) to be blended so that the water contact angle of the ink-receiving layer can be adjusted to 80° or less.

[0032] (Silicone-based leveling agent (B)) In the present invention, the composition for forming the ink-receiving layer and the ink-receiving layer contain a silicone-based leveling agent (B). If the composition for forming the ink-receiving layer and the ink-receiving layer do not contain the silicone-based leveling agent (B), it will be impossible to suppress print unevenness. The silicone-based leveling agent (B) is presumed to have the effect of suppressing partial surface free energy disturbances on the surface of the ink-receiving layer caused by silicone components migrating from the back surface of the release liner to the ink-receiving layer, homogenizing the surface free energy within the ink-receiving layer surface, and suppressing variations in interference between dots within the ink-receiving layer surface. It is believed that this effect suppresses print unevenness.

[0033] The silicone leveling agent (B) is a compound having a siloxane skeleton, and specifically includes one or more compounds selected from compounds having a siloxane skeleton and an organic functional group, compounds having a siloxane skeleton and an organic modified group, etc. The organic modified group refers to a group in which a part of the organic functional group is substituted with another group. Specific examples of the silicone leveling agent (B) include polyether-modified silicone oils (manufactured by Dow-Toray Industries, Inc.) such as DOWSIL (registered trademark) BY16-036 Fluid, DOWSIL SH28 Paint Additive, DOWSIL SF8428 Fluid, DOWSIL 501W Additive, DOWSIL L-7001 Fluid, DOWSIL FZ-2104 Fluid, DOWSIL L-7002 Fluid, and DOWSIL SF8427 Fluid; DOWSIL (registered trademark) SF8416 Fluid, DOWSIL BY16-846 Fluid, DOWSIL SH203 Fluid, and DOWSIL 56 Alkyl-modified silicone oils such as Additive (manufactured by Dow-Toray Industries, Inc.); carboxyl-modified silicone oils such as DOWSIL (registered trademark) BY-16-880 and BY16-750 Fluid (manufactured by Dow-Toray Industries, Inc.); amino-modified silicone oils such as XIAMETER (registered trademark) OFX-8417 Fluid, DOWSIL (registered trademark) BY-16-849 Fluid, DOWSIL (registered trademark) FZ-3785 Fluid, DOWSIL (registered trademark) 16-872 Fluid, and DOWSIL (registered trademark) 16-853U Fluid (manufactured by Dow-Toray Industries, Inc.); DOWSIL (registered trademark) SF8413 Fluid, DOWSIL SF8411 Fluid, DOWSIL BY16-839 Fluid, and DOWSIL (registered trademark) SF8412 Fluid. Examples of the silicone leveling agent (B) include epoxy-modified silicone oils (manufactured by Dow-Toray Industries, Inc.), such as FZ-3736 Fluid, SF8421 EG Fluid, BY16-870 Fluid, BY16-876 Fluid, BY16-869 Fluid, and BY16-760 Fluid. Among these, polyether-modified silicone oils are more preferred. The silicone leveling agent (B) may be used alone or in combination of two or more.

[0034] In one embodiment of the present invention, the content of the silicone-based leveling agent (B) in the ink-receiving layer-forming composition is appropriately adjusted so as to suppress printing unevenness and adjust the water contact angle of the ink-receiving layer to 80° or less. Increasing the content of the silicone-based leveling agent (B) in the ink-receiving layer-forming composition increases the water contact angle of the ink-receiving layer. Conversely, decreasing the content of the silicone-based leveling agent (B) in the ink-receiving layer-forming composition decreases the water contact angle of the ink-receiving layer. Taking this tendency into consideration, the content of the silicone-based leveling agent (B) is adjusted so as to adjust the water contact angle of the ink-receiving layer to 80° or less, from the viewpoint of balancing with the effect of the energy ray-curable compound (A) in improving the hydrophilicity of the ink-receiving layer. For example, the content of the silicone-based leveling agent (B) is preferably 0.01 to 0.06 parts by mass, more preferably 0.02 to 0.05 parts by mass, per 100 parts by mass of the energy ray-curable compound (A). In addition, the ink receiving layer 1 m ２ An example of the content of the silicone-based leveling agent (B) per unit area is preferably 0.12 mg / m ２ ~1.0 mg / m ２ , more preferably 0.27 mg / m ２ ~0.75 mg / m ２ is.

[0035] (Filler (C)) In one aspect of the present invention, the ink-receiving layer-forming composition and the ink-receiving layer preferably further contain a filler (C). By including the ink-receiving layer-forming composition and the ink-receiving layer in the filler (C), the slipperiness of the surface of the ink-receiving layer can be improved, making it easier to improve the transportability of the inkjet printing sheet. Here, "improved transportability" means improving the slipperiness between inkjet printing sheets and between the inkjet printing sheet and the device (roller or cylinder). This allows the inkjet printing sheet to be smoothly wound and unwound, making it easier to prevent wrinkles or scratches on the sheet, misalignment of the printing position, etc.

[0036] Examples of the filler (C) include silica, alumina, titania, and zirconia oxide, but silica is preferred in that it does not impair the transparency of the ink-receiving layer.

[0037] The particle size of the filler (C) is preferably 10 nm to less than 1 μm, more preferably 10 nm to 500 nm, and even more preferably 10 nm to 100 nm. When the particle size of the filler (C) is within the above range, the slipperiness of the surface of the ink-receiving layer is improved, which makes it easier to improve the transportability of the ink-jet printing sheet, and the transparency of the ink-receiving layer is less likely to be impaired. The particle size of the filler (C) is the average primary particle size converted from the specific surface area by the BET method.

[0038] The filler (C) may be in the form of a dry powder, but from the viewpoint of dispersion stability, it is preferable to use a colloidal solution obtained by dispersing the filler in an organic solvent.

[0039] The filler (C) may be used alone or in combination of two or more.

[0040] In one embodiment of the present invention, the content of the filler (C) in the composition for forming an ink-receiving layer is not particularly limited, but from the viewpoint of improving the slipperiness of the surface of the ink-receiving layer and facilitating the improvement of the transportability of the inkjet printing sheet, and from the viewpoint of making it difficult to impair the transparency of the ink-receiving layer, the content is preferably 20 to 500 parts by mass, more preferably 30 to 300 parts by mass, even more preferably 40 to 200 parts by mass, and still more preferably 50 to 150 parts by mass relative to 100 parts by mass of the energy ray-curable compound (A).

[0041] (Photopolymerization initiator (D)) In one aspect of the present invention, the composition for forming the ink-receiving layer and the ink-receiving layer preferably contain a photopolymerization initiator (D). When the composition for forming the ink-receiving layer contains the photopolymerization initiator (D) together with the energy ray-curable compound (A), it is possible to facilitate the progress of energy ray curing by ultraviolet rays or the like. As the photopolymerization initiator (D), any general compound having the function of facilitating the progress of energy ray curing by ultraviolet rays or the like can be used without any particular limitation. Examples of such compounds include 1-hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloroanthraquinone, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methylpropan-1-one, etc. The photopolymerization initiator (D) may be used alone or in combination of two or more.

[0042] In one embodiment of the present invention, the content of the photopolymerization initiator (D) in the composition for forming an ink-receiving layer is not particularly limited, but is preferably 0.1 to 10 parts by mass relative to 100 parts by mass of the energy ray-curable compound (A).

[0043] (Other Additives) In one embodiment of the present invention, the composition for forming the ink-receiving layer may or may not contain other components other than the energy ray-curable compound (A), the silicone-based leveling agent (B), the filler (C), and the photopolymerization initiator (D), as long as the water contact angle of the ink-receiving layer can be adjusted to 80° or less. For example, the composition for forming the ink-receiving layer may or may not contain an energy ray-curable compound (A') other than the energy ray-curable compound (A), as long as the water contact angle of the ink-receiving layer can be adjusted to 80° or less.

[0044] <Substrate> The inkjet printing sheet of the present invention has a substrate, which functions as a support for supporting the inkjet printing sheet and the printing portion formed on the ink-receiving layer.

[0045] The substrate is not particularly limited, but is preferably a resin sheet. By using a resin sheet as the substrate, the inkjet printing sheet can be improved in rigidity, flexibility, etc., and the inkjet printing sheet can be easily handled. This is also advantageous from the viewpoint of reducing the production cost and weight of the inkjet printing sheet.

[0046] Examples of resins that may be used to form the resin sheet include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefin resins such as polyethylene and polypropylene; polystyrene; acrylonitrile-butadiene-styrene copolymers; cellulose triacetate; polycarbonate; urethane resins such as polyurethane and acrylic-modified polyurethane; polymethylpentene; polysulfone; polyether ether ketone; polyethersulfone; polyphenylene sulfide; polyimide resins such as polyetherimide and polyimide; polyamide resins; acrylic resins; fluorine-based resins, etc. Among these, from the viewpoint of easily improving adhesion to the ink-receiving layer, polyester resins and polyolefin resins are preferred, polyester resins are more preferred, and polyethylene terephthalate is even more preferred.

[0047] The resin sheet may be composed of only one type of resin, or may be composed of two or more types of resin. When the resin sheet is composed of two or more types of resin, it is preferable that the resin sheet is a multi-layered body. Furthermore, from the viewpoint of easily improving adhesion with the ink-receiving layer, the uppermost layer of the multi-layered body (the layer in contact with the ink-receiving layer) is preferably a polyester-based resin, more preferably polyethylene terephthalate. Furthermore, the resin sheet may be unstretched, or may be stretched uniaxially or biaxially, e.g., longitudinally or transversely.

[0048] In addition, the resin sheet may contain, together with these resins, additives for the substrate, such as a surface conditioner, a plasticizer, an ultraviolet absorber, a light stabilizer, and a colorant. The content of the additives for the substrate is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less, based on the total amount of the substrate.

[0049] The thickness of the substrate is not particularly limited, but is preferably 15 μm to 300 μm, more preferably 30 μm to 200 μm.

[0050] <Adhesive Layer> The inkjet printing sheet of the present invention has an adhesive layer. By having an adhesive layer, the inkjet printing sheet of the present invention can be suitably used as an adhesive sheet.

[0051] The adhesive constituting the adhesive layer is not particularly limited, and examples thereof include acrylic adhesives, urethane adhesives, and the like. When the inkjet printing sheet is used for applications such as window displays, the adhesive layer may be formed from an acrylic adhesive from the viewpoint of weather resistance, etc. Furthermore, when removability from the adherend is required, the adhesive layer may be formed from a urethane adhesive. The adhesive layer may contain other components such as ultraviolet absorbers, tackifiers, antioxidants, light stabilizers, softeners, silane coupling agents, and fillers, as necessary. These may be used alone or in combination of two or more.

[0052] The thickness of the adhesive layer is not particularly limited, but from the viewpoint of improving the handleability when using the inkjet printing sheet as an adhesive sheet, it is preferably 5 μm to 100 μm, more preferably 10 μm to 70 μm, and even more preferably 15 μm to 50 μm.

[0053] <Release Liner> The inkjet printing sheet of the present invention has a release liner. By covering the adhesive surface of the pressure-sensitive adhesive layer of the inkjet printing sheet of the present invention with a release liner, the adhesive surface of the pressure-sensitive adhesive layer can be suitably protected during transportation and storage of the inkjet printing sheet.

[0054] In the inkjet printing sheet of the present invention, the release liner has a silicone-based release agent layer. When the release liner is rolled or wound, a very small amount of silicone components may migrate to the back surface of the release liner. Therefore, when the inkjet printing sheet having the above-described laminated structure is rolled or wound, the very small amount of silicone components present on the back surface of the release liner may migrate to the ink-receiving layer. The silicone components that migrate from the back surface of the release liner to the ink-receiving layer cause localized surface free energy disturbances on the surface of the ink-receiving layer. As a result, interference between dots within the ink-receiving layer varies, resulting in print unevenness. However, according to the present invention, by incorporating a silicone-based leveling agent (B) into the ink-receiving layer-forming composition and the ink-receiving layer, the localized surface free energy disturbances on the surface of the ink-receiving layer are suppressed, the surface free energy of the ink-receiving layer is homogenized, and the variation in interference between dots within the ink-receiving layer is suppressed, thereby suppressing print unevenness. Furthermore, by making the water contact angle of the ink-receiving layer 80° or less, the decrease in print density that occurs when the silicone-based leveling agent (B) is blended is suppressed, and sufficient print density can be ensured.

[0055] As the silicone-based release agent layer that constitutes the release liner, any material that is generally used for release liners can be used without any particular limitation.

[0056] The support constituting the release liner may be a sheet substrate or a paper substrate commonly used for release liners. Examples of the sheet substrate include polyester resins such as polyethylene terephthalate, and polyolefin resins such as polyethylene resins and polypropylene resins. Examples of the paper substrate include papers such as fine paper, kraft paper, and glassine paper.

[0057] The thickness of the release liner is not particularly limited, but is preferably 10 μm to 150 μm, more preferably 20 μm to 130 μm, and even more preferably 30 μm to 120 μm.

[0058] [Method for producing inkjet printing sheet] The method for producing the inkjet printing sheet of the present invention is not particularly limited, and may be appropriately selected depending on the configuration of the inkjet printing sheet.

[0059] A preferred method for forming the ink-receiving layer involves applying an ink-receiving layer-forming composition containing an energy ray-curable compound (A) and a silicone-based leveling agent (B) to one surface of a substrate to form a coating film, drying the coating film, and then curing it. As described above, the ink-receiving layer-forming composition preferably further contains a filler (C). As described above, the ink-receiving layer-forming composition preferably further contains a photopolymerization initiator (D). In order to improve the workability of application to the substrate, the ink-receiving layer-forming composition is preferably further diluted with a dilution solvent to form a solution.

[0060] Examples of dilution solvents include organic solvents such as methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, and isopropanol. The concentration of the active ingredients (solid content) in the solution of the composition for forming the ink-receiving layer is preferably 10 to 50% by mass.

[0061] Examples of methods for applying the solution of the composition for forming the ink-receiving layer include bar coating, gravure coating, roll coating, knife coating, and die coating.

[0062] The heating conditions for drying the coating film are, for example, a drying temperature of 60° C. to 120° C. and a drying time of 30 seconds to 3 minutes.

[0063] After drying the coating film, the coating film is irradiated with energy rays (preferably ultraviolet rays) to cure (polymerize) the energy ray-curable compound (A). When ultraviolet rays are used as the energy rays, the irradiation conditions of the ultraviolet rays are an integrated irradiation amount (integrated light amount) of 5 to 1200 mJ / cm. 2 is preferred, and 30 to 500 mJ / cm 2 The ultraviolet light can be irradiated using, for example, a high-pressure mercury lamp, an electrodeless lamp, a xenon lamp, an LED, or the like as an ultraviolet light source.

[0064] The pressure-sensitive adhesive layer of the inkjet printing sheet of one embodiment of the present invention is formed on the other side of the substrate, on which the ink-receiving layer is not formed. The pressure-sensitive adhesive layer is formed, for example, by applying a composition for forming a pressure-sensitive adhesive layer (pressure-sensitive adhesive layer-forming composition) to the other side of the substrate, and a release liner is then laminated on the pressure-sensitive adhesive layer. Alternatively, the pressure-sensitive adhesive layer may be formed by applying the pressure-sensitive adhesive layer-forming composition to the release surface of the release liner (the surface of the silicone-based release agent layer), and this may then be laminated to the other side of the substrate. The method for applying the pressure-sensitive adhesive layer-forming composition is the same as the method for applying the ink-receiving layer-forming composition described above.

[0065] [Ink for Inkjet Printing] The inkjet printing sheet of the present invention is effective in ensuring sufficient print density while suppressing print unevenness in inkjet printing using ultraviolet-curable ink or latex ink, which does not or is unlikely to penetrate into the ink-receiving layer, and is particularly effective in ensuring sufficient print density while suppressing print unevenness in inkjet printing using ultraviolet-curable ink.

[0066] <UV-curable ink> The UV-curable ink is an ink that does not substantially contain an organic solvent and is cured by irradiation with UV light. The UV-curable ink contains a photopolymerizable monomer, a colorant that is a pigment or dye, and a photopolymerization initiator that starts a polymerization reaction. In one aspect of the present invention, from the viewpoint of further improving the adhesion between the ink-receiving layer and the printed portion, it is preferable that the UV-curable ink contains an acrylic monomer.

[0067] (Photopolymerizable Monomer) Examples of photopolymerizable monomers include monofunctional acrylates, difunctional acrylates, polyfunctional acrylates, and mixtures thereof. It should be noted that the photopolymerizable monomer may be an acrylic monomer formed by combining one or more of these acrylates. Examples of monofunctional acrylates include hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, phenol EO-modified (n=2) acrylate, 2-ethylhexyl EO-modified (n=2) acrylate, 2-hydroxy-3-phenoxypropyl acrylate, isobornyl acrylate, and acryloylmorpholine. Examples of bifunctional acrylates include hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, neopentyl glycol hydroxypivalate diacrylate, and bisphenol A EO-modified (n=4) diacrylate. Examples of polyfunctional acrylates include trimethylolpropane triacrylate, pentaerythritol triacrylate, trimethylolpropane PO-modified (n=3) triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate.

[0068] (Colorant) The ultraviolet curable ink usually contains a colorant, which may be any of various dyes, pigments, etc.

[0069] (Photopolymerization initiator) A photopolymerization initiator generally initiates a polymerization reaction by irradiation with ultraviolet light. As such a photopolymerization initiator, for example, a photopolymerization initiator that is a single agent or a mixture of multiple agents may be used, or a combination of a photopolymerization initiator and a photosensitizer may be used. For example, a combination of multiple photopolymerization initiators with different excitation wavelengths, or a combination to which a photosensitizer has been added, may be used.

[0070] (Other Components) As other components, for example, various conventionally known components such as dispersants, stabilizers, surfactants, etc. may be further blended as necessary.

[0071] <Latex Ink> Latex ink contains a liquid dispersion medium and a dispersoid composed of a material containing at least a resin, which is dispersed (emulsified and / or suspended) in the dispersion medium.

[0072] (Resin) The resin contained in the latex ink is not particularly limited, but examples thereof include vinyl resins, acrylic resins, styrene resins, alkyd resins, polyester resins, polyurethane resins, epoxy resins, phenoxy resins, polyolefin resins, and modified resins thereof (for example, modified resins modified to be water-soluble), and one or more types selected from these may be used in combination.

[0073] (Dispersion Medium) The latex ink contains water as a dispersion medium.

[0074] (Colorant) Latex ink usually contains a colorant, which may be any of various dyes, pigments, etc.

[0075] (Other Components) The latex ink may contain components other than those described above (other components), such as dispersants, antifungals, antirust agents, pH adjusters, surfactants, plasticizers, UV absorbers, and light stabilizers.

[0076] [Method of forming printed portion] The printed portion using inkjet printing ink is formed by applying the inkjet printing ink onto the ink-receiving layer of the inkjet printing sheet by an inkjet method. Examples of inkjet methods include a piezo method and a thermal jet method. When applying an ultraviolet-curable ink as inkjet printing ink, the amount of ultraviolet light irradiated onto the ultraviolet-curable ink is not particularly limited, but is preferably 40 J / m 2 ~400 J / m 2 The heating temperature of the latex ink when applying the latex ink as the inkjet printing ink is not particularly limited, but is preferably 40°C to 90°C. By the above method, a printed matter having a printed portion on the ink-receiving layer of the inkjet printing sheet in which print unevenness caused by the inkjet printing ink is suppressed while ensuring sufficient print density can be obtained. Note that the inkjet printing sheet of the present invention can suppress print unevenness even in inkjet printing using a reduced amount of ink. Specifically, even when the total ink amount is 10% to 70% (preferably 10% to 50%, more preferably 15% to 40%), it is possible to form a printed portion in which print unevenness is suppressed while ensuring sufficient print density.

[0077] [Uses of Inkjet Printing Sheet] The inkjet printing sheet of the present invention is used for printing using inkjet printing ink. Therefore, according to the present invention, there is provided a method of use in which the inkjet printing sheet is used to form a printed section on the ink-receiving layer of the inkjet printing sheet using inkjet printing ink. The present invention also provides a method for producing a printed matter, which includes a step of forming a printed section on the ink-receiving layer of the inkjet printing sheet using inkjet printing ink. Furthermore, according to the present invention, there is provided a printed matter having a printed section printed with inkjet printing ink on the ink-receiving layer of the inkjet printing sheet.

[0078] Inkjet printing using ultraviolet-curable ink and latex ink is employed in the method of use, method of producing a printed matter, and printed matter of one embodiment of the present invention. The method of use, method of producing a printed matter, and printed matter of the present invention use the inkjet printing sheet of the present invention, and therefore, even in inkjet printing using ultraviolet-curable ink and latex ink, which do not or are unlikely to penetrate into the ink-receiving layer, it is possible to form a printed portion that ensures sufficient print density while suppressing print unevenness. Among ultraviolet-curable inks and latex inks, ultraviolet-curable inks are particularly suitable for use.

[0079] Furthermore, in the method of use, method of producing a printed matter, and printed matter of one embodiment of the present invention, the total amount of ink used in inkjet printing is not particularly limited, but the effects of the present invention are particularly likely to be achieved when the total amount of ink is preferably 10% to 70%, more preferably 10% to 50%, and even more preferably 15% to 40%. According to the method of use, method of producing a printed matter, and printed matter of one embodiment of the present invention, even with the above ink amount, sufficient print density is ensured while suppressing print unevenness. Therefore, this is particularly useful when printing with shades or gradations.

[0080] The present invention will be specifically described with reference to the following examples, but the present invention is not limited to these examples.

[0081] [Examples 1 to 12, Comparative Examples 1 to 4] Inkjet printing sheets of Examples 1 to 12 and Comparative Examples 1 to 4 were prepared by the following procedure.

[0082] <Preparation of composition for forming ink-receiving layer> A composition for forming an ink-receiving layer was prepared having the formulation shown in Table 1. Details of the raw materials used in preparing the composition for forming the ink-receiving layer are shown below.

[0083] (Energy ray-curable compounds (A)) "Compound 1": ethylene oxide-modified hexafunctional polyglycerin acrylate (the polyol compound is an ethylene oxide-modified product of polyglycerin (a tetramer of glycerin), which is a complete ester having six acryloyl groups. The number of moles of ethylene oxide is 6.) "Compound 2": ethylene oxide-modified dipentaerythritol hexaacrylate (the polyol compound is an ethylene oxide-modified product of dipentaerythritol, which is a complete ester having six acryloyl groups. The number of moles of ethylene oxide is 12.) "Compound 3": ethylene oxide-modified pentaerythritol tetraacrylate (the polyol compound is an ethylene oxide-modified product of pentaerythritol, which is a complete ester having four acryloyl groups. The number of moles of ethylene oxide is 35.) "Compound 4": dipentaerythritol pentaacrylate (the polyol compound is dipentaerythritol and is a partial ester having five acryloyl groups. The hydroxyl value is 90 mgKOH / g.) "Compound 5": glycerin diacrylate (the polyol compound is glycerin and is a partial ester having two acryloyl groups. The hydroxyl value is 240 mgKOH / g.) "Compound 6": ethylene oxide-modified sorbitol diacrylate (the polyol compound is an ethylene oxide-modified sorbitol and is a partial ester having two acryloyl groups. The number of moles of ethylene oxide is 6.) "Compound 7": dipentaerythritol hexaacrylate (the polyol compound is dipentaerythritol and is a complete ester having six acryloyl groups. The hydroxyl value is 10 mgKOH / g.)

[0084] The above compounds 1 to 7 all correspond to esters of a polyol compound and (meth)acrylic acid. The above compound 1 further satisfies the above requirement (X2) and the above requirement (X3). The above compound 2 further satisfies the above requirement (X2). The above compound 3 further satisfies the above requirement (X2). The above compound 4 further satisfies the above requirement (X1). The above compound 5 further satisfies the above requirement (X1) and the above requirement (X3). The above compound 6 further satisfies the above requirement (X1) and the above requirement (X2).

[0085] (Silicone leveling agent (B)) Polyether-modified silicone oil

[0086] (Filler (C)) Organosilica sol (particle diameter 70-100 nm)

[0087] (Photopolymerization initiator (D)) 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methylpropan-1-one

[0088] Each composition for forming an ink-receiving layer having the composition shown in Table 1 (amounts of active ingredients converted into active ingredients) was diluted with a dilution solvent (ethyl acetate) to prepare a coating liquid with an active ingredient concentration of 30% by mass, and used to prepare a sheet for inkjet printing.

[0089] (Preparation of inkjet printing sheet) The prepared ink-receiving layer-forming composition was applied to one side of a polyethylene terephthalate substrate (thickness: 50 μm) using a bar coater so that the film thickness after drying would be 2.5 μm. Next, the solvent contained in the ink-receiving layer-forming composition applied to the substrate was removed by heating at 70° C. for 1 minute using a hot air dryer, and then ultraviolet light having a peak wavelength of 365 nm was applied at an integrated light intensity of 90 mJ / cm ２

[0042] The ink-receiving layer was then formed by irradiating the release liner with light. Next, a release liner (thickness: 50 μm) was prepared, with a silicone-based release agent layer provided on one side of a polyethylene terephthalate sheet. An acrylic pressure-sensitive adhesive was applied to the silicone-based release agent layer side so that the film thickness after drying would be 20 μm. The coating was then heated at 90°C for 1 minute using a hot air dryer to remove the solvent contained in the coating liquid, thereby forming an acrylic pressure-sensitive adhesive layer. The acrylic pressure-sensitive adhesive layer formed on the release liner was then bonded to the surface of the substrate opposite the ink-receiving layer, to obtain a sheet for inkjet printing.

[0090] <Evaluation> The evaluations described in (1) to (4) below were carried out. When carrying out the evaluations (2) and (3) below, the pretreatment described below was carried out, assuming that the ink-receiving layer would come into contact with the back surface of the release liner due to the ink-jet printing sheet being rolled up. That is, two identical ink-jet printing sheets were prepared, and as shown in Figure 2, they were stacked so that the surface of the ink-receiving layer 2x of one ink-jet printing sheet 1x came into contact with the back surface of the release liner 5y of the other ink-jet printing sheet 1y, and the sheets were subjected to a pressure of 20 kg / cm in an environment at a temperature of 70°C. ２ The mixture was left standing for 12 hours under a pressure of 1.0 MPa.

[0091] (1) Measurement of Water Contact Angle of Ink-Receiving Layer The water contact angle was measured using an automatic contact angle meter DSA100S (manufactured by KRUSS) for the ink-receiving layers (portions of the ink-receiving layer to which ink for inkjet printing is applied) of the ink-jet printing sheets of Examples 1 to 12 and Comparative Examples 1 to 4. The measurement was carried out in an atmosphere of 23°C and 50% RH, and 2 μL of water was dropped, and the static contact angle was calculated by the θ / 2 method.

[0092] (2) Evaluation of Printing Unevenness Printed portions were formed on the surface of the ink-receiving layer of each of the inkjet printing sheets of Examples 1 to 12 and Comparative Examples 1 to 4 by inkjet printing using an inkjet printer (UCJV300, manufactured by Mimaki Engineering Co., Ltd.) using ultraviolet-curable ink (LUS-170, manufactured by Mimaki Engineering Co., Ltd.) with 5% each of CMYK and a total ink amount of 20% by ink jet method. After printing was completed, the entire printed surface was visually observed and evaluated according to the following criteria: A: No printing unevenness was observed on the entire printed surface. B: Slight printing unevenness was observed on part of the printed surface, but this did not pose a major problem in terms of print quality. C: Light and dark shading was noticeable on the entire printed surface, and printing unevenness was significant.

[0093] (3) Evaluation of Print Density A print was formed on the surface of the ink-receiving layer of each of the inkjet printing sheets of Examples 1 to 12 and Comparative Examples 1 to 4 by printing with an inkjet printer (UCJV300, manufactured by Mimaki Engineering Co., Ltd.) using ultraviolet-curable ink (LUS-170, manufactured by Mimaki Engineering Co., Ltd.) with an ink volume of 20% and ink color Y by the inkjet method. After printing was completed, the entire printed surface was visually observed and evaluated according to the following criteria: A: Sufficient print density was observed. B: The print density was slightly low, but there was no major problem in terms of print quality. C: The print density was low.

[0094] (4) Dynamic Frictional Force The dynamic frictional force of the ink-receiving layer of each of the inkjet printing sheets of Examples 1 to 12 against a stainless steel plate was measured in accordance with JIS K7125:1999, with a surface load of 9.8 N and a test speed of 10 mm / min. The results are shown as "(average of minimum dynamic frictional force) - (average of maximum dynamic frictional force)." A smaller maximum dynamic frictional force indicates improved slipperiness of the ink-receiving layer.

[0095] The evaluation results are shown in Table 1.

[0096]

[0097] The results shown in Table 1 reveal the following. The results shown in Examples 1 to 12 reveal that when the water contact angle of the ink-receiving layer formed from the ink-receiving layer-forming composition containing the specific energy ray-curable compound (A) and silicone-based leveling agent (B) is 80° or less, it is possible to ensure sufficient print density while suppressing print unevenness. In contrast, as shown in Comparative Examples 1 and 2, it is clear that the ink-receiving layer formed from the ink-receiving layer-forming composition not containing the silicone-based leveling agent (B) can ensure sufficient print density but cannot suppress print unevenness. Furthermore, as shown in Comparative Examples 3 and 4, when the water contact angle of the ink-receiving layer formed from the ink-receiving layer-forming composition containing the energy ray-curable compound (A) and silicone-based leveling agent (B) is 81° or more, it is clear that while print unevenness can be suppressed, sufficient print density cannot be secured. Furthermore, a comparison of Examples 1 and 8 with Example 7 reveals that the inclusion of filler (C) improves the slipperiness of the ink-receiving layer.

[0098] 1, 1x, 1y Inkjet printing sheet 2, 2x, 2y Ink receiving layer 3, 3x, 3y Substrate 4, 4x, 4y Pressure sensitive adhesive layer 5, 5x, 5y Release liner 5a, 5ax, 5ay Silicone release agent layer 5b, 5bx, 5by Support

Claims

1. A laminated structure including an ink-receiving layer, a substrate, a pressure-sensitive adhesive layer, and a release liner in this order; the release liner has a silicone-based release agent layer on a surface that comes into contact with the pressure-sensitive adhesive layer, the ink-receiving layer is a cured layer of an ink-receiving layer-forming composition containing an energy ray-curable compound (A) and a silicone-based leveling agent (B); The energy ray-curable compound (A) is an ester of a polyol compound and (meth)acrylic acid, The ink-jet printing sheet, wherein the ink-receiving layer has a water contact angle of 80° or less.

2. The sheet for inkjet printing according to claim 1, wherein the energy ray-curable compound (A) further satisfies one or more of the following requirements (X1) to (X3): Requirement (X1): The ester is a partial ester. Requirement (X2): The polyol compound constituting the ester is an alkylene oxide modified product, provided that the alkylene group constituting the alkylene oxide modified product has 2 to 4 carbon atoms. Requirement (X3): The polyol compound constituting the ester has a glycerin skeleton.

3. The sheet for ink-jet printing according to claim 1 or 2, wherein the composition for forming the ink-receiving layer further contains a filler (C).

4. 3. The sheet for ink-jet printing according to claim 1, which is in the form of a roll or a wound body wound around a core material.

5. A method for using the sheet for ink-jet printing according to claim 1 or 2 to form a printed portion on the ink-receiving layer of the sheet for ink-jet printing by using an ink for ink-jet printing.

6. A method for producing a printed matter, comprising a step of forming a printed portion on the ink-receiving layer of the sheet for ink-jet printing according to claim 1 or 2, using an ink for ink-jet printing.

7. A printed matter having a printed portion printed with an ink for ink-jet printing on the ink-receiving layer of the sheet for ink-jet printing according to claim 1 or 2.