Inkjet printing sheet

Abstract

The present invention addresses the problem of providing an inkjet printing sheet that has an ink-receiving layer having excellent blocking resistance while having excellent ink adhesion and excellent water adhesion resistance of ink. The problem is solved by having a laminated structure in which an ink-receiving layer (X) and a base material (Y) are laminated, and the ink-receiving layer (X) is formed from a resin composition (x1) containing: an acrylic resin (A) having a crosslinkable functional group; a crosslinking agent (B); an ultraviolet curable acrylate compound (C); a photopolymerization initiator (D); and a silicone-based surface modifier (E) having a (meth)acryloyl group.

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 on an inkjet printing medium to form dots. Inkjet recording is rapidly becoming more popular due to its advantages, such as the ease with which high-quality full-color images can be obtained, ease of high-speed printing, and 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 can be used as a label or the like by being attached to various members.

[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] In order to ensure adhesion between the ink-receiving layer and the ink-printed portion (hereinafter referred to simply as "ink adhesion"), the ink-receiving layer must have a certain degree of softness. Inkjet printing sheets are sometimes applied to glass surfaces in stores, showrooms, offices, etc. for advertising and decorative purposes. When applying an inkjet printing sheet to an adherend such as a glass surface, water or an aqueous solution containing a surfactant is sprayed onto the application surface (adhesive layer surface) of the inkjet printing sheet or onto the surface of the adherend where the inkjet printing sheet is to be applied, so as to prevent air from getting between the inkjet printing sheet and the adherend. After the two sheets are brought into close contact and positioned, a squeegee is used to remove the water and air from the inkjet printing sheet side to apply the sheet. This is commonly known as water application. In this case, the aqueous solution may also be sprayed onto the ink-receiving layer side, which is the side opposite the adhesive layer, to increase the slipperiness of the squeegee. Therefore, the ink receiving layer of an inkjet printing sheet that is subjected to water lamination is required to ensure adhesion between the ink-printed portion of the ink receiving layer and the ink even when the ink receiving layer is rubbed with a squeegee while in contact with water.

[0007] However, adjusting the ink-receiving layer to be soft in order to more easily ensure ink adhesion and water-resistant adhesion of the ink in the ink-receiving layer causes the problem of making it difficult to ensure blocking resistance of the ink-receiving layer. Conversely, adjusting the ink-receiving layer to be hard makes it easier to ensure blocking resistance, but causes the problem of making it difficult to ensure ink adhesion and water-resistant adhesion of the ink in the ink-receiving layer (particularly water-resistant adhesion of the ink). For this reason, it has conventionally been difficult to create an inkjet printing sheet having an ink-receiving layer that is excellent in both ink adhesion and water-resistant adhesion of the ink and in blocking resistance.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an ink-jet printing sheet having an ink-receiving layer that is excellent in ink adhesion and water-resistant ink adhesion, while also exhibiting excellent blocking resistance.

[0009] In this specification, "ink adhesion" refers to the adhesion between the ink-receiving layer and a printed portion formed on the ink-receiving layer when the printed portion is not in contact with liquid water. The quality of this adhesion is evaluated, for example, by an ink adhesion test in the Examples described later. In this specification, "water-resistant ink adhesion" refers to the adhesion between the ink-receiving layer and a printed portion formed on the ink-receiving layer when the printed portion is in contact with liquid water. The quality of this adhesion is evaluated, for example, by an ink water-resistant ink adhesion test in the Examples described later.

[0010] As a result of extensive research aimed at solving the above-mentioned problems, the present inventors have discovered that the above-mentioned problems can be solved by an ink-receiving layer formed from a resin composition containing an acrylic resin having a crosslinkable functional group, a specific crosslinking agent, a specific ultraviolet-curable acrylate compound, a specific surface modifier, and a photopolymerization initiator. Based on this discovery, the present inventors have conducted further research and have completed the present invention.

[0011] That is, the present invention relates to the following [1] to [7]. [1] A laminated structure in which an ink-receiving layer (X) and a substrate (Y) are laminated, wherein the ink-receiving layer (X) is formed from a resin composition (x1) containing an acrylic resin (A) having a crosslinkable functional group, a crosslinking agent (B), an ultraviolet-curable acrylate compound (C), a photopolymerization initiator (D), and a silicone-based surface modifier (E) having a (meth)acryloyl group, wherein the crosslinking agent (B) contains an isocyanurate-based compound (B1) having no (meth)acryloyl group, wherein the isocyanurate-based compound (B1) contains an isocyanurate compound (B1-1) and a modified isocyanurate compound (B1-2), wherein the isocyanurate compound (B1-1) is a trimer of 1,6-hexamethylene diisocyanate, and wherein the modified isocyanurate compound (B1-2) is a trimer of 1,6-hexamethylene diisocyanate and has one or more tertiary amino groups, An inkjet printing sheet, wherein the UV-curable acrylate compound (C) comprises a first UV-curable acrylate compound (C1) having a nurate skeleton and a second UV-curable acrylate compound (C2) not having a nurate skeleton. [2] The inkjet printing sheet according to [1] above, wherein the substrate (Y) comprises a polyester-based resin. [3] The inkjet printing sheet according to [1] or [2] above, wherein the ink-receiving layer (X) is laminated on one surface of the substrate (Y), and a pressure-sensitive adhesive layer (Z) is provided on the other surface of the substrate (Y). [4] The inkjet printing sheet according to [3] above, wherein the adhesive surface of the pressure-sensitive adhesive layer (Z) is covered with a release liner. [5] A method of use, comprising using the inkjet printing sheet to form 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. [6] A method for producing a printed matter, comprising a step of forming a printed part on the ink-receiving layer of the ink-jet printing sheet according to any one of [1] to [4] above, using an ink for ink-jet printing. [7] A printed matter having a printed part printed with an ink for ink-jet printing on the ink-receiving layer of the ink-jet printing sheet according to any one of [1] to [4] above.

[0012] According to the present invention, it is possible to provide a sheet for ink jet printing having an ink-receiving layer that is excellent in ink adhesion and water-resistant ink adhesion, and also excellent in blocking resistance.

[0013] 1 is a cross-sectional view schematically illustrating one embodiment of a sheet for inkjet printing according to the present invention.

[0014] As used herein, the term "active ingredient" refers to the components contained in the target composition, excluding diluting solvents such as water and organic solvents. In addition, as used herein, "(meth)acrylic acid" refers to both "acrylic acid" and "methacrylic acid." Furthermore, "(meth)acryloyl group" refers to both "acryloyl group" and "methacryloyl group." Furthermore, as used herein, for preferred numerical ranges (e.g., ranges of content, etc.), the lower and upper limits 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 yield "10 to 60." Furthermore, as used herein, the numerical values ​​in the examples are numerical values ​​that can be used as upper or lower limits.

[0015] [Embodiments of Inkjet Printing Sheet] The inkjet printing sheet of this embodiment has a laminated structure in which an ink-receiving layer (X) and a substrate (Y) are laminated together. The ink-receiving layer (X) is formed from a resin composition (x1) containing an acrylic resin (A) having a crosslinkable functional group, a crosslinking agent (B), an ultraviolet-curable acrylate compound (C), a photopolymerization initiator (D), and a silicone-based surface modifier (E) having a (meth)acryloyl group. The crosslinking agent (B) contains an isocyanurate-based compound (B1) that does not contain a (meth)acryloyl group. The isocyanurate-based compound (B1) contains an isocyanurate compound (B1-1) and a modified isocyanurate compound (B1-2). The isocyanurate compound (B1-1) is a trimer of 1,6-hexamethylene diisocyanate, and the modified isocyanurate compound (B1-2) is a trimer of 1,6-hexamethylene diisocyanate and has one or more tertiary amino groups. The ultraviolet-curable acrylate compound (C) includes a first ultraviolet-curable acrylate compound (C1) having a nurate skeleton and a second ultraviolet-curable acrylate compound (C2) not having a nurate skeleton.

[0016] As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that an ink-receiving layer (X) formed from a resin composition (x1) containing "an acrylic resin (A) having a crosslinkable functional group," "a crosslinking agent (B)," "an ultraviolet-curable acrylate compound (C)," "a photopolymerization initiator (D)," and "a silicone-based surface modifier (E) having a (meth)acryloyl group" has excellent ink adhesion and water-resistant ink adhesion, as well as excellent blocking resistance. Further, through various studies, the present inventors have completed the present invention.

[0017] The inkjet printing sheet of this embodiment will be described in detail below in terms of its configuration, the components constituting the inkjet printing sheet (substrate, ink-receiving layer, adhesive layer, and release liner), the method for producing the inkjet printing sheet, and uses of the inkjet printing sheet.

[0018] [Configuration of Inkjet Printing Sheet] The inkjet printing sheet of this embodiment has a laminated structure in which an ink-receiving layer (X) and a substrate (Y) are laminated.

[0019] Figure 1 shows a schematic cross-sectional view of one embodiment of the inkjet printing sheet of this embodiment. The inkjet printing sheet 1 shown in Figure 1 has a laminated structure in which an ink-receiving layer (X) is laminated on one surface (Ya) of a substrate (Y). Here, as shown in Figure 1, the inkjet printing sheet of this embodiment preferably has a pressure-sensitive adhesive layer (Z) provided on the other surface (Yb) of the substrate (Y). This allows the inkjet printing sheet to be suitably used as a pressure-sensitive adhesive film.

[0020] Although not shown, the adhesive surface of the pressure-sensitive adhesive layer (Z) may be covered with a release liner. The release liner may be peeled off when the pressure-sensitive adhesive layer (Z) is attached to an adherend, thereby exposing the adhesive surface of the pressure-sensitive adhesive layer (Z). Although not shown, an ink-receiving layer (X) may be provided on both the one surface (Ya) and the other surface (Yb) of the substrate (Y) without providing the pressure-sensitive adhesive layer (Z). Although not shown, another layer may be provided between the ink-receiving layer (X) and the substrate (Y). Examples of such another layer include an easy-adhesion layer.

[0021] [Components Constituting the Inkjet Printing Sheet] The inkjet printing sheet of this embodiment has an ink-receiving layer (X) and a substrate (Y). As already described, the inkjet printing sheet of this embodiment may further have a pressure-sensitive adhesive layer (Z) in addition to the ink-receiving layer (X) and the substrate (Y). In addition to the ink-receiving layer (X) and the substrate (Y), it may further have a pressure-sensitive adhesive layer (Z) and a release liner. The ink-receiving layer (X), the substrate (Y), the pressure-sensitive adhesive layer (Z), and the release liner will be described in detail below.

[0022] <Ink-receiving layer (X)> The inkjet printing sheet of this embodiment has an ink-receiving layer (X). The ink-receiving layer (X) is the portion to which ink is applied, and has the function of fixing the portion printed with the applied ink. The thickness of the ink-receiving layer (X) is not particularly limited, but is preferably 0.05 μm to 50 μm, more preferably 0.1 μm to 25 μm, and even more preferably 0.1 μm to 10 μm.

[0023] The ink-receiving layer (X) is formed from a resin composition (x1) containing an acrylic resin (A) having a crosslinkable functional group, a crosslinking agent (B), an ultraviolet-curable acrylate compound (C), a photopolymerization initiator (D), and a silicone-based surface modifier (E) having a (meth)acryloyl group. By forming the resin composition (x1) from the resin composition (x1) containing the acrylic resin (A) having a crosslinkable functional group, the crosslinking agent (B), the ultraviolet-curable acrylate compound (C), the photopolymerization initiator (D), and the silicone-based surface modifier (E) having a (meth)acryloyl group, a crosslinked structure (a structure formed by a thermosetting component) formed by the reaction between the acrylic resin (A) having a crosslinkable functional group and the crosslinking agent (B) and a polymer structure (a structure formed by an ultraviolet-curable component) formed by the ultraviolet-curable acrylate compound (C) and the photopolymerization initiator (D) are mixed on the surface of the ink-receiving layer (X). Furthermore, by including a silicone-based surface modifier (E) having a (meth)acryloyl group in the layer in which these are mixed, it is possible to obtain an ink-receiving layer that is excellent in ink adhesion, water-resistant ink adhesion, and blocking resistance.

[0024] In the following description, the “acrylic resin (A) having a crosslinkable functional group,” “crosslinking agent (B),” “ultraviolet-curable acrylate compound (C),” “photopolymerization initiator (D),” and “silicone-based surface modifier (E) having a (meth)acryloyl group” will also be referred to as “component (A),” “component (B),” “component (C),” “component (D),” and “component (E),” respectively.

[0025] In this embodiment, the resin composition (x1) used to form the ink-receiving layer (X) may be composed solely of components (A), (B), (C), (D), and (E). However, it may also contain components other than components (A), (B), (C), (D), and (E) in addition to components (A), (B), (C), (D), and (E), as long as the effects of the present invention are not significantly impaired. Examples of such components include additives commonly used in ink-receiving layers, such as reaction accelerators (catalysts), plasticizers, fillers, and colorants.

[0026] In the present embodiment, the total content of the component (A), the component (B), the component (C), the component (D), and the component (E) is preferably 80% by mass to 100% by mass, more preferably 85% by mass to 100% by mass, and even more preferably 90% by mass to 100% by mass, based on the total amount of the active components of the resin composition (x1).

[0027] The acrylic resin (A) having a crosslinkable functional group, the crosslinking agent (B), the ultraviolet-curable acrylate compound (C), the photopolymerization initiator (D), and the silicone-based surface modifier (E) having a (meth)acryloyl group will be described in detail below.

[0028] (Acrylic Resin (A) Having Crosslinkable Functional Group) The resin composition (x1) used in this embodiment contains an acrylic resin (A) having a crosslinkable functional group. As the acrylic resin (A) having a crosslinkable functional group, an acrylic resin (A1) having a structural unit (a1) derived from a crosslinkable functional group-containing monomer (a1′) (hereinafter also referred to as monomer (a1′)) is preferred.

[0029] Examples of the crosslinkable functional group possessed by the monomer (a1') include one or more selected from a hydroxyl group, a carboxyl group, an amino group, and an epoxy group. That is, examples of the monomer (a1') include a hydroxyl group-containing monomer, a carboxyl group-containing monomer, an amino group-containing monomer, and an epoxy group-containing monomer. Examples also include a monomer containing two or more crosslinkable functional groups selected from a hydroxyl group, a carboxyl group, an amino group, and an epoxy group. These monomers (a1') may be used alone or in combination of two or more. Among these, hydroxyl group-containing monomers and carboxyl group-containing monomers are preferred as the monomer (a1').

[0030] Examples of the hydroxyl group-containing monomer include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; N-methylol acrylamide; ε-caprolactone-modified hydroxy(meth)acrylate; and carbonate-modified (meth)acrylate.

[0031] Examples of the carboxy group-containing monomer include (meth)acrylic acid; and compounds obtained by reacting the terminal hydroxyl group of the hydroxy group-containing monomer described above with an acid anhydride such as one or more aliphatic dicarboxylic acids selected from succinic anhydride, glutaric anhydride, and the like.

[0032] Here, the acrylic resin (A) having a crosslinkable functional group may be an acrylic copolymer (A2) having a structural unit (a2) derived from an alkyl (meth)acrylate (a2') (hereinafter also referred to as "monomer (a2')") together with the crosslinkable functional group-containing monomer (a1').

[0033] The number of carbon atoms in the alkyl group of the monomer (a2') is preferably 1 to 24. From the viewpoint of adjusting the glass transition temperature (Tg) of the acrylic resin (A) within an appropriate range and thereby making it easier to exhibit ink adhesion, the number of carbon atoms in the alkyl group is preferably 2 to 20. The alkyl group of the monomer (a2') may be a linear alkyl group or a branched alkyl group.

[0034] Examples of the monomer (a2') include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, and stearyl (meth)acrylate. These monomers (a2') may be used alone or in combination of two or more.

[0035] In the acrylic copolymer (A2) containing the structural unit (a2), the content of the structural unit (a2) is preferably from 1 to 99 mass%, more preferably from 5 to 95 mass%, and even more preferably from 10 to 90 mass%, based on the total amount of the acrylic copolymer (A2).

[0036] The acrylic resin (A1) and the acrylic copolymer (A2) may be an acrylic copolymer (A3) further having a structural unit (a3) ​​derived from a monomer (a3') other than the monomers (a1') and (a2').

[0037] Examples of the monomer (a3′) include olefins such as ethylene, propylene, and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; diene monomers such as butadiene, isoprene, and chloroprene; (meth)acrylates having a cyclic structure such as cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and imide (meth)acrylate; styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, (meth)acrylamide, (meth)acrylonitrile, (meth)acryloylmorpholine, and N-vinylpyrrolidone.

[0038] In the acrylic copolymer (A3) containing the structural unit (a3), the content of the structural unit (a3) ​​is preferably from 1 to 99 mass%, more preferably from 5 to 95 mass%, and even more preferably from 10 to 90 mass%, based on the total amount of the acrylic copolymer (A3).

[0039] The molecular weight of the acrylic resin (A) having a crosslinkable functional group is not particularly limited, but the number average molecular weight is preferably 3,000 to 100,000. The number average molecular weight is a polystyrene-equivalent value measured by gel permeation chromatography (GPC) using a differential refractometer.

[0040] Here, the hydroxyl value of the acrylic resin (A) having a crosslinkable functional group is preferably 5.0 mgKOH / g to 25.0 mgKOH / g, more preferably 6.0 mgKOH / g to 24.0 mgKOH / g, and even more preferably 7.0 mgKOH / g to 23.0 mgKOH / g. When the hydroxyl value of the acrylic resin (A) having a crosslinkable functional group is equal to or greater than the above-mentioned lower limit, ink adhesion is easily improved. Furthermore, the stability of the ink-receiving layer is easily improved. When the hydroxyl value of the acrylic resin (A) having a crosslinkable functional group is equal to or less than the above-mentioned upper limit, the stability of the coating liquid (a solution containing the resin composition (x1)) used to form the ink-receiving layer (X) is easily improved. Note that, in this specification, the hydroxyl value of the acrylic resin (A) having a crosslinkable functional group means a value measured in accordance with JIS K0070:1992.

[0041] The acid value of the acrylic resin (A) having a crosslinkable functional group is preferably 10.0 mgKOH / g or less, more preferably 1.0 mgKOH / g to 9.0 mgKOH / g, and even more preferably 2.0 mgKOH / g to 8.0 mgKOH / g. In this specification, the acid value of the acrylic resin (A) having a crosslinkable functional group means a value measured in accordance with JIS K0070:1992.

[0042] The glass transition temperature (Tg) of the acrylic resin (A) having a crosslinkable functional group is preferably 100°C or lower, more preferably 95°C or lower, and even more preferably 90°C or lower, from the viewpoint of further improving ink adhesion. In particular, when the glass transition temperature (Tg) of the acrylic resin (A) having a crosslinkable functional group is lower than the curing temperature of the ink, ink adhesion is more likely to be further improved. Furthermore, from the viewpoint of further improving blocking resistance, the glass transition temperature (Tg) of the acrylic resin (A) having a crosslinkable functional group is usually 30°C or higher, preferably 40°C or higher, and more preferably 50°C or higher. In this specification, the glass transition temperature (Tg) of the acrylic resin (A) having a crosslinkable functional group refers to a value measured in accordance with JIS K 7121:1987 using a differential scanning calorimeter (manufactured by TA Instruments Japan, product name "DSC Q2000") at a heating rate of 20°C / min.

[0043] (Crosslinking Agent (B)) The resin composition (x1) used in this embodiment contains a crosslinking agent (B). The crosslinking agent (B) includes an isocyanurate-based compound (B1) that does not have a (meth)acryloyl group. In the following description, the "isocyanurate-based compound (B1) that does not have a (meth)acryloyl group" will also be simply referred to as the "isocyanurate-based compound (B1)." If the crosslinking agent (B) does not include the isocyanurate-based compound (B1), the ink-receiving layer (X) will not have good ink adhesion. In this embodiment, it is presumed that the use of a crosslinking agent (B) containing the isocyanurate-based compound (B1) results in a crosslinked structure formed by the reaction with the acrylic resin (A) having a crosslinkable functional group, which contributes to ink adhesion and ensures excellent ink adhesion. Furthermore, if the crosslinking agent (B) does not include the isocyanurate-based compound (B1), the adhesion between the ink-receiving layer (X) and the substrate (Y) will not be ensured. It is presumed that by using the crosslinking agent (B) containing the isocyanurate compound (B1), an ink-receiving layer (X) having a crosslinked structure that exhibits excellent adhesion to the substrate (Y), particularly to a substrate (Y) containing a polyester resin such as polyethylene terephthalate, is formed due to the influence of the polar group of the isocyanurate compound (B1).

[0044] In the present embodiment, from the viewpoint of further improving ink adhesion, the content of the isocyanurate compound (B1) is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, even more preferably 80% by mass to 100% by mass, and still more preferably 90% by mass to 100% by mass, based on the total amount of the crosslinking agent (B). The isocyanurate compound (B1) will be described in detail below.

[0045] (Isocyanurate Compound (B1)) In the present embodiment, the isocyanurate compound (B1) includes an isocyanurate compound (B1-1) and a modified isocyanurate compound (B1-2). From the viewpoint of further improving ink adhesion, the total content of the isocyanurate compound (B1-1) and the modified isocyanurate compound (B1-2) in the isocyanurate compound (B1) is preferably 80% by mass to 100% by mass, more preferably 90% by mass to 100% by mass, and even more preferably 95% by mass to 100% by mass, based on the total amount of the isocyanurate compound (B1).

[0046] —Isocyanurate Compound (B1-1)— The isocyanurate compound (B1) includes an isocyanurate compound (B1-1), which is a trimer of 1,6-hexamethylene diisocyanate, and specifically, is a compound represented by the following formula (1):

[0047] - Isocyanurate Compound (B1-2) - The isocyanurate compound (B1) includes a modified isocyanurate compound (B1-2). The modified isocyanurate compound (B1-2) is a trimer of 1,6-hexamethylene diisocyanate and has one or more tertiary amino groups.

[0048] An example of a method for introducing one or more tertiary amino groups into the compound of formula (1) to form a modified product is a method of reacting a modifying agent having a hydroxyl group and a tertiary amino group with the compound of formula (1). Examples of such modifiers include N,N-dimethylaminohexanol (e.g., Kao Riser No. 25, manufactured by Kao Corporation), N,N-dimethylaminoethoxyethoxyethanol (e.g., Kao Riser No. 23NP, manufactured by Kao Corporation), N,N-dimethylaminoethoxyethanol (e.g., Kao Riser No. 26, manufactured by Kao Corporation), N,N,N'-trimethylaminoethylethanolamine (e.g., TOYOCAT RX5, manufactured by Tosoh Corporation), 2-[[3-(dimethylamino)propyl]methylamino]ethanol (e.g., POLYCAT 17, manufactured by Evonik), and N,N-dimethylethanolamine (e.g., JEFFCAT DMEA, manufactured by Huntsman). The modifier may have a ring structure, but is preferably a compound as described above that does not have a ring structure. The modifier is preferably an organic non-metallic compound as described above that does not contain a metal element. That is, the modifying agent is preferably an acyclic organic non-metallic compound having a hydroxyl group and a tertiary amino group.

[0049] The reaction of the compound of formula (1) with the modifier is preferably carried out, for example, by charging the compound of formula (1) and the modifier into a nitrogen-substituted reaction vessel and stirring at a reaction temperature of 60°C to 100°C for 1 hour to 5 hours.

[0050] - Preparation of Isocyanurate Compound (B1) - The isocyanurate compound (B1) can be prepared, for example, by appropriately adjusting the ratio of the amounts of the compound of formula (1) and the modifier added to a reaction vessel when reacting the compound of formula (1) with the modifier described above. The ratio of the modifier added to the compound of formula (1) is preferably 0.01 to 10 parts by mass, and more preferably 0.05 to 5 parts by mass, per 100 parts by mass of the compound of formula (1). This results in only a portion of the numerous compounds of formula (1) having one or more tertiary amino groups, making it possible to prepare an isocyanurate compound (B1) containing the isocyanurate compound (B1-1) and a modified isocyanurate compound (B1-2). The content of the modified isocyanurate compound (B1-2) is preferably 0.5 mol % to 10 mol %, more preferably 1 mol % to 5 mol %, based on the total amount of the isocyanurate compound (B1).

[0051] (Content of Crosslinking Agent (B)) From the viewpoint of improving the effects of the present invention, the content of the crosslinking agent (B) is preferably 3.0 parts by mass or more, more preferably 5.0 parts by mass or more, and even more preferably 7.0 parts by mass or more, relative to 100 parts by mass of the acrylic resin (A) having a crosslinkable functional group, and is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less.

[0052] (UV-Curable Acrylate Compound (C)) The resin composition (x1) used in this embodiment contains a UV-curable acrylate compound (C). The UV-curable acrylate compound (C) is a component that can be cured (polymerized) by irradiation with UV rays. In this embodiment, the UV-curable acrylate compound (C) includes a first UV-curable acrylate compound (C1) having a nurate skeleton and a second UV-curable acrylate compound (C2) that does not have a nurate skeleton. If the UV-curable acrylate compound (C) does not include the first UV-curable acrylate compound (C1) having a nurate skeleton, the water-resistant adhesion of the latex ink will be insufficient. On the other hand, if the UV-curable acrylate compound (C) does not include the second UV-curable acrylate compound (C2), the blocking resistance will be insufficient. In this embodiment, from the viewpoint of improving the effects of the present invention, the total content of the first ultraviolet-curable acrylate compound (C1) and the second ultraviolet-curable acrylate compound (C2) is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, even more preferably 80% by mass to 100% by mass, and still more preferably 90% by mass to 100% by mass, based on the total amount of the ultraviolet-curable acrylate compound (C). Hereinafter, the first ultraviolet-curable acrylate compound (C1) and the second ultraviolet-curable acrylate compound (C2) will be described in detail.

[0053] (First UV-Curable Acrylate Compound (C1)) The first UV-Curable acrylate compound (C1) is not particularly limited as long as it is an UV-Curable acrylate compound having a nurate skeleton. From the viewpoint of improving the effects of the present invention, the first UV-Curable acrylate compound (C1) is preferably a polyfunctional acrylate compound having a nurate skeleton, and more preferably a di- or tri-functional acrylate compound having a nurate skeleton (i.e., an acrylate compound having a nurate skeleton and 2 to 3 (meth)acryloyl groups).

[0054] A more preferred example of the first ultraviolet-curable acrylate compound (C1) is a compound (C1-1) represented by the following general formula (1).

[0055] In the above general formula, X １ , X ２ , and X ３ are each independently a hydrogen atom, —C(═O)CH═CH ２ or a hydrocarbon group having 1 to 10 carbon atoms. １ , X ２ , and X ３ At least one (preferably two or more) of the groups is -C(=O)CH=CH ２ It is. １ , L ２ , and L ３ are each independently -(R １ O) ｍ -or- (R １ O) ｍ -[C(=O)R ２ O] ｎ Indicates -. １ is an alkylene group having 1 to 4 carbon atoms (preferably 2 to 3 carbon atoms, more preferably 2 carbon atoms). ２ is an alkylene group having 1 to 8 carbon atoms (preferably 4 to 6 carbon atoms, more preferably 5 carbon atoms). m is an integer of 1 to 10. m is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1. n is an integer of 1 to 10. n is preferably 1 to 2, and more preferably 1. Preferred examples of the compound (C1-1) represented by the general formula (1) include ε-caprolactone-modified tris-(2-acryloxyethyl)isocyanurate.

[0056] (Second UV-Curable Acrylate Compound (C2)) The second UV-Curable acrylate compound (C2) is not particularly limited as long as it is a UV-Curable acrylate compound that does not have a nurate skeleton, but from the viewpoint of improving the effects of the present invention, it is preferably a polyfunctional acrylate compound that does not have a nurate skeleton, more preferably a tetra- to hexa-functional acrylate compound that does not have a nurate skeleton (i.e., an acrylate compound that does not have a nurate skeleton and has 4 to 6 (meth)acryloyl groups), and even more preferably a penta- to hexa-functional acrylate compound that does not have a nurate skeleton (i.e., an acrylate compound that does not have a nurate skeleton and has 5 to 6 (meth)acryloyl groups).

[0057] More preferred compounds for the second ultraviolet-curable acrylate compound (C2) include esters (C2-1) of polyol compounds and (meth)acrylic acid. Examples of polyol compounds include trimethylolethane, trimethylolpropane, trimethylolbutane, ditrimethylolpropane, tritrimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, polyglycerin, 1,3,5-pentanetriol, sorbitol, adonitol, arabitol, xylitol, and mannitol. Oxyalkylene-modified products of these polyol compounds (the number of carbon atoms in the alkylene group is preferably 1 to 4) are also included. Among these, from the viewpoint of improving the effects of the present invention, pentaerythritol and dipentaerythritol are preferred, and dipentaerythritol is more preferred.

[0058] From the viewpoint of improving the effects of the present invention, the number of (meth)acryloyl groups in the second ultraviolet-curable acrylate compound (C2) is preferably 4 or more, more preferably 4 to 6, and even more preferably 5 to 6. The second ultraviolet-curable acrylate compound (C2) may be a complete ester or a partial ester, but preferably contains a complete ester.

[0059] (Ratio of Contents of First Ultraviolet-Curable Acrylate Compound (C1) and Second Ultraviolet-Curable Acrylate Compound (C2)) In this embodiment, from the viewpoint of improving the water-resistant adhesion of the ink (particularly the water-resistant adhesion of a latex ink), the ratio of the content of the first ultraviolet-curable acrylate compound (C1) to the content of the second ultraviolet-curable acrylate compound (C2) [(C1) / (C2)] is preferably 3.0 or more, more preferably 5.0 or more, even more preferably 7.0 or more, and still more preferably 8.0 or more, in terms of mass ratio. Also, it is preferably 15 or less, more preferably 12 or less.

[0060] (Photopolymerization initiator (D)) The resin composition (x1) used in this embodiment contains a photopolymerization initiator (D). As the photopolymerization initiator (D), a general photopolymerization initiator used when curing the ultraviolet-curable acrylate compound (C) with ultraviolet light can be used as appropriate. Specific examples 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, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide.

[0061] The content of the photopolymerization initiator (D) is preferably 0.1 to 10 parts by mass based on 100 parts by mass of the ultraviolet-curable acrylate compound (C).

[0062] (Silicone-based surface modifier (E) having a (meth)acryloyl group) The resin composition (x1) used in this embodiment contains a silicone-based surface modifier (E) having a (meth)acryloyl group. When the resin composition (x1) contains the silicone-based surface modifier (E) having a (meth)acryloyl group, the ink-receiving layer (X) formed from the resin composition (x1) can have excellent blocking resistance. Note that when a silicone-based surface modifier not having a (meth)acryloyl group is contained instead of the silicone-based surface modifier (E) having a (meth)acryloyl group, the blocking resistance of the ink-receiving layer (X) formed from the resin composition (x1) cannot be improved. As the silicone-based surface modifier (E) having a (meth)acryloyl group, commercially available agents such as surface conditioners or leveling agents can be used as appropriate. (Meth) Examples of commercially available silicone surface modifiers (E) having an acryloyl group include EBECRYL350 (manufactured by Daicel-Allnex Co., Ltd.), BYK-333 (manufactured by BYK Japan Co., Ltd.), BYK-377 (manufactured by BYK Japan Co., Ltd.), BYK-378 (manufactured by BYK Japan Co., Ltd.), BYK-UV3500 (manufactured by BYK Japan Co., Ltd.), BYK-UV3505 (manufactured by BYK Japan Co., Ltd.), BYK-UV3576 (manufactured by BYK Japan Co., Ltd.), X-22-164A (manufactured by Shin-Etsu Chemical Co., Ltd.), X-22-164B (manufactured by Shin-Etsu Chemical Co., Ltd.), X-22-164C (manufactured by Shin-Etsu Chemical Co., Ltd.), X-22-164E (manufactured by Shin-Etsu Chemical Co., Ltd.), and X-22-174BX (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0063] (Total content of components (A) and (C)) In this embodiment, from the viewpoint of improving the effects of the present invention, the total content of the acrylic resin (A) having a crosslinkable functional group and the ultraviolet-curable acrylate compound (C) is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more, relative to the total content (100% by mass) of the acrylic resin (A) having a crosslinkable functional group, the crosslinking agent (B), the ultraviolet-curable acrylate compound (C), the photopolymerization initiator (D), and the silicone-based surface modifier (E) having a (meth)acryloyl group. Also, it is preferably 97% by mass or less, more preferably 95% by mass or less.

[0064] (Content Ratio of Component (A) to Component (C)) In the present embodiment, the content ratio [(A) / (C)] of the acrylic resin (A) having a crosslinkable functional group to the ultraviolet-curable acrylate compound (C) is, in terms of mass ratio, preferably 0.10 to 0.40, more preferably 0.15 to 0.35, and even more preferably 0.18 to 0.30, from the viewpoint of improving blocking resistance, ink adhesion, and water-resistant adhesion of the ink in a well-balanced manner.

[0065] (Ratio of Component (E) to Component (A) and Component (C)) In the present embodiment, the ratio of the content of the silicone-based surface modifier (E) having a (meth)acryloyl group to the total content of the acrylic resin (A) having a crosslinkable functional group and the ultraviolet-curable acrylate compound (C) [(E) / {(A)+(C)}] is, in terms of mass ratio, preferably 0.0005 to 0.0030, more preferably 0.0006 to 0.0020, and even more preferably 0.0007 to 0.0015, from the viewpoint of improving blocking resistance, ink adhesion, and water-resistant adhesion of the ink in a balanced manner.

[0066] <Substrate (Y)> The inkjet printing sheet of this embodiment has a substrate (Y). The substrate (Y) supports the ink-receiving layer (X) and also functions as a support for supporting the printing portion formed on the ink-receiving layer (X).

[0067] The substrate (Y) is not particularly limited, but is preferably a resin film. When the substrate (Y) is a resin film, the rigidity, flexibility, etc. of the inkjet printing sheet are improved, 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.

[0068] Here, the substrate (Y) is preferably a transparent resin film. By using the substrate (Y) as a transparent resin film, a printed matter having a printed portion formed on the ink-receiving layer of the inkjet printing sheet can be suitably used for applications such as glass decoration in stores, showrooms, offices, etc.

[0069] Examples of resins constituting the resin film include polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefin resins such as polyethylene and polypropylene; polystyrene; acrylonitrile-butadiene-styrene copolymer; cellulose triacetate; polycarbonate; urethane resins such as polyurethane and acrylic-modified polyurethane; polymethylpentene; polysulfone; polyether ether ketone; polyethersulfone; polyphenylene sulfide; polyimide-based resins such as polyetherimide and polyimide; polyamide-based resins; acrylic resins; fluorine-based resins, etc. Among these, from the viewpoint of easily improving the adhesion between the ink-receiving layer (X) and the substrate (Y), polyester-based resins and polyolefin-based resins are preferred, polyester-based resins are more preferred, and polyethylene terephthalate is even more preferred.

[0070] The resin film may be composed of only one type of resin, or may be composed of two or more types of resin. When the resin film is composed of two or more types of resin, it is preferable that the resin film is a multi-layered body. Furthermore, from the viewpoint of easily improving the adhesion between the ink-receiving layer (X) and the substrate (Y), 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.

[0071] The resin film may be unstretched or may be stretched uniaxially, such as longitudinally or transversely, or biaxially.

[0072] In addition, the resin film may contain, together with these resins, additives for the substrate, such as a surface conditioner, a plasticizer, an ultraviolet absorber, a light stabilizer, a colorant, etc. 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 (Y).

[0073] The thickness of the substrate (Y) is not particularly limited, but is preferably 15 μm to 300 μm, more preferably 30 μm to 200 μm.

[0074] <Adhesive Layer (Z)> The inkjet printing sheet of the present embodiment may have an adhesive layer (Z). When the inkjet printing sheet of the present embodiment has the adhesive layer (Z), the inkjet printing sheet can be suitably used as an adhesive film.

[0075] The adhesive constituting the adhesive layer is not particularly limited, and examples thereof include acrylic adhesives, urethane adhesives, and silicone adhesives.

[0076] The thickness of the pressure-sensitive adhesive layer (Z) is not particularly limited, but from the viewpoint of improving the handleability when the inkjet printing sheet is used as a pressure-sensitive adhesive film, it is preferably 5 μm to 100 μm, more preferably 10 μm to 70 μm, and even more preferably 15 μm to 50 μm.

[0077] <Release Liner> The inkjet printing sheet of this embodiment may have a release liner together with the pressure-sensitive adhesive layer (Z). By covering the adhesive surface of the pressure-sensitive adhesive layer (Z) of the inkjet printing sheet of this embodiment with a release liner, the adhesive surface of the pressure-sensitive adhesive layer (Z) can be suitably protected during transportation and storage of the inkjet printing sheet.

[0078] The release liner is not particularly limited, and release liners commonly used in the field of adhesive films can be used as appropriate. Examples of release liners include laminates in which a release layer is provided on the surface of a film substrate or a paper substrate. Examples of film substrates include polyester resins such as polyethylene terephthalate, and polyolefin resins such as polyethylene resins and polypropylene resins. Examples of paper substrates include papers such as fine paper, kraft paper, and glassine paper. Examples of materials constituting the release layer include silicone, long-chain alkyl resins, and fluorine-based resins.

[0079] 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 100 μm.

[0080] [Method for Manufacturing Inkjet Printing Sheet] There are no particular limitations on the method for manufacturing the inkjet printing sheet of this embodiment, and the method may be appropriately selected depending on the configuration of the inkjet printing sheet.

[0081] <Method of Forming Ink-Receiving Layer (X)> A preferred method of forming the ink-receiving layer (X) is to apply the resin composition (x1) to one surface (Ya) of the substrate (Y) to form a coating film, dry the coating film, and then UV-cure and crosslink the coating film to form the ink-receiving layer (X). In order to improve the workability of application to the substrate (Y), the resin composition (x1) is preferably further diluted with a dilution solvent to form a solution.

[0082] Examples of the dilution solvent 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 ingredient in the solution of the resin composition (x1) is preferably 10 to 50% by mass.

[0083] Examples of the method for applying the solution of the resin composition (x1) include Mayer bar coating, gravure coating, roll coating, knife coating, and die coating.

[0084] The resin composition (x1) is applied to one surface (Ya) of the substrate (Y) to form a coating film, and then the coating film is dried to remove the dilution solvent from the coating film (drying step). Heating conditions for drying the coating film include, for example, a drying temperature of 60°C to 120°C and a drying time of 30 seconds to 3 minutes.

[0085] After drying the coating film, the coating film is irradiated with ultraviolet light to cure (polymerize) the ultraviolet-curable acrylate compound (C) (ultraviolet light irradiation step). The ultraviolet light irradiation conditions are an integrated irradiation amount (integrated light amount) of 5 to 1200 mJ / cm. 2 is preferred, and 50 to 500 mJ / cm 2 The ultraviolet light can be irradiated using, for example, a high-pressure mercury lamp, an electrodeless UV lamp, a xenon lamp, an LED, or the like as an ultraviolet light source.

[0086] After curing (polymerizing) the ultraviolet-curable acrylate compound (C), the acrylic resin (A) having a crosslinkable functional group is reacted with the crosslinking agent (B) to form a crosslinked structure (crosslinking step). The crosslinking conditions are not particularly limited, and for example, the crosslinking may be carried out by leaving the mixture in a normal environment (e.g., 23°C, relative humidity 50°C) for 1 day to 14 days or less, or by leaving the mixture in an environment of 40°C to 60°C for 1 day to 3 days.

[0087] The ultraviolet irradiation step may be performed before, during, or after the crosslinking step. The crosslinking step and the ultraviolet irradiation step may be performed simultaneously, or the crosslinking step and the ultraviolet irradiation step may each be performed multiple times. Furthermore, at least one of the ultraviolet irradiation step and the crosslinking step may be performed simultaneously with the drying step.

[0088] <Method of Forming Pressure-Sensitive Adhesive Layer (Z)> When the inkjet printing sheet of this embodiment has a pressure-sensitive adhesive layer (Z), the pressure-sensitive adhesive layer (Z) is formed on the other surface (Yb) of the substrate (Y) on which the ink-receiving layer (X) is not formed. The pressure-sensitive adhesive layer (Z) is formed, for example, by applying a composition for forming the pressure-sensitive adhesive layer (pressure-sensitive adhesive layer-forming composition) to the other surface (Yb) of the substrate (Y). Alternatively, the pressure-sensitive adhesive layer (Z) may be formed by applying the pressure-sensitive adhesive layer-forming composition to the release surface of a release liner, and then the pressure-sensitive adhesive layer (Z) may be laminated (transferred) to the other surface (Yb) of the substrate (Y). The method of applying the pressure-sensitive adhesive layer-forming composition is the same as that described above for the resin composition (x1).

[0089] [Uses of Inkjet Printing Sheet] The inkjet printing sheet of this embodiment is used for printing using inkjet printing ink. Therefore, this embodiment provides 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. This embodiment also provides a method for producing a printed item, which includes a step of forming a printed section on the ink-receiving layer of the inkjet printing sheet using inkjet printing ink. This embodiment also provides a printed item having a printed section printed with inkjet printing ink on the ink-receiving layer of the inkjet printing sheet.

[0090] <Inkjet Printing Ink> Examples of inkjet printing inks include ultraviolet-curable inks, latex inks, and solvent inks. Among these inkjet printing inks, the inkjet printing sheet of this embodiment can achieve excellent ink adhesion and water-resistant ink adhesion even in inkjet printing using ultraviolet-curable inks or latex inks, which do not or are unlikely to penetrate into the ink-receiving layer.

[0091] <<UV-Curable Ink>> UV-curable ink is an ink that contains substantially no organic solvent and cures upon exposure to 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 this embodiment, when an ink-receiving layer containing an acrylic resin as described above is used, the UV-curable ink preferably contains an acrylic monomer, from the viewpoint of further improving adhesion between the ink-receiving layer and the printed portion.

[0092] (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 (HPA), tetrahydrofurfuryl acrylate (THFA), phenol EO-modified (n=2) acrylate, 2-ethylhexyl EO-modified (n=2) acrylate, 2-hydroxy-3-phenoxypropyl acrylate, isobornyl acrylate (IBXA), and acryloylmorpholine (ACMO). Examples of bifunctional acrylates include hexanediol diacrylate (HDDA), neopentyl glycol diacrylate (NPGDA), tripropylene glycol diacrylate (TPGDA), neopentyl glycol hydroxypivalate diacrylate (MANDA), bisphenol A EO-modified (n=4) diacrylate (A-BPE4), etc. Examples of polyfunctional acrylates include trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PETA), trimethylolpropane PO-modified (n=3) triacrylate (TMPPOA), ditrimethylolpropane tetraacrylate (DTMPTA), pentaerythritol tetraacrylate (PETTA), dipentaerythritol pentaacrylate (DPPA), dipentaerythritol hexaacrylate (DPHA), etc.

[0093] (Colorant) The ultraviolet curable ink usually contains a colorant, which may be any of various dyes, pigments, etc.

[0094] (Photopolymerization initiator) A photopolymerization initiator generally initiates a polymerization reaction by irradiation with ultraviolet (UV) rays. 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.

[0095] (Other Components) As other components, for example, various conventionally known components such as dispersants, stabilizers, surfactants, etc. may be further blended as necessary.

[0096] <<Latex Ink>> Latex ink contains a liquid dispersion medium and a dispersoid that is dispersed (emulsified and / or suspended) in the dispersion medium and is made up of a material that contains at least a resin.

[0097] (Resin) The resin contained in the latex ink is not particularly limited, and examples thereof include vinyl resins, acrylic resins, styrene resins, alkyd resins, polyester resins, polyurethane resins, silicone resins, fluorine-based resins, epoxy resins, phenoxy resins, polyolefin resins, and modified resins thereof (for example, modified resins modified to be water-soluble), and one or more selected from these may be used in combination. When an ink-receiving layer containing such an acrylic resin is used, the latex ink used in the inkjet printing sheet of this embodiment is preferably a latex ink containing an acrylic resin, from the viewpoint of further improving adhesion between the ink-receiving layer and the printed portion.

[0098] (Dispersion Medium) The latex ink contains water as a dispersion medium.

[0099] (Colorant) Latex ink usually contains a colorant, which may be any of various dyes, pigments, etc.

[0100] (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.

[0101] (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 irradiation to the ultraviolet-curable ink is not particularly limited, but is preferably 40 J / m 2 ~400 J / m 2 When applying the latex ink as the ink for inkjet printing, the heating temperature of the latex ink is not particularly limited, but is preferably 40°C to 100°C.

[0102] The present invention will be specifically described with reference to the following examples, but the present invention is not limited to these examples.

[0103] [Methods for measuring various physical properties] The methods for measuring various physical properties in the present examples are as follows. (1) Hydroxyl value The hydroxyl value of the acrylic resin (A) having a crosslinkable functional group was measured in accordance with JIS K0070:1992. (2) Acid value The acid value of the acrylic resin (A) having a crosslinkable functional group was measured in accordance with JIS K0070:1992. (3) Glass transition temperature (Tg) The glass transition temperature (Tg) of the acrylic resin (A) having a crosslinkable functional group was measured in accordance with JIS K 7121:2012 using a differential scanning calorimeter (manufactured by TA Instruments Japan, product name "DSC Q2000") at a heating rate of 20°C / min. (4) Thickness of Each Layer The thickness of each layer was measured using a constant pressure thickness measuring instrument manufactured by Teclock Corporation (model number: "PG-02J", standard specifications: JIS K6783: 1994, JIS Z1702: 1994, JIS Z1709: 1995).

[0104] [Examples 1 to 4, Comparative Examples 1 to 5] Inkjet printing sheets of Examples 1 to 4 and Comparative Examples 1 to 5 were prepared by the following procedure.

[0105] <Preparation of Resin Composition> The resin composition was prepared using an acrylic resin (A) having a crosslinkable functional group, a crosslinking agent (B), an ultraviolet-curable acrylate compound (C), a photopolymerization initiator (D), and a silicone-based surface modifier (E) having a (meth)acryloyl group (or a silicone-based surface modifier (E′) not having a (meth)acryloyl group), as shown below.

[0106] (Acrylic Resin (A) Having Crosslinkable Functional Group) An acrylic resin having a crosslinkable functional group, which has a hydroxyl value of 11.0 mgKOH / g, an acid value of 3.9 mgKOH / g, and a glass transition temperature (Tg) of 90°C, was used.

[0107] (Crosslinking Agent (B)) A partially modified product of an isocyanurate compound (an isocyanurate compound (B1) containing an isocyanurate compound (B1-1) and a modified product of an isocyanurate compound (B1-2)) was used.

[0108] (UV-curable acrylate compound (C)) - "First UV-curable acrylate compound (C1)": ε-caprolactone-modified tris-(2-acryloxyethyl) isocyanurate was used. - "Second UV-curable acrylate compound (C2)": Dipentaerythritol polyacrylate was used. The dipentaerythritol polyacrylate is an ester of dipentaerythritol and acrylic acid, and is an ester having 5 to 6 acryloyl groups.

[0109] (Photopolymerization initiator (D)) 1-hydroxycyclohexyl phenyl ketone was used.

[0110] (Silicone-based surface modifier (E) having a (meth)acryloyl group) BYK-UV3500 (manufactured by BYK Corporation) was used.

[0111] (Silicone-based surface modifier (E') having no (meth)acryloyl group) DOWSIL SH28 Paint additive (manufactured by Dow Corporation) was used.

[0112] (Other additives) Tin-based catalysts

[0113] As the substrate (Y), a polyethylene terephthalate sheet (thickness: 50 μm) with an easy-adhesion layer was prepared. Then, an acrylic resin (A) having a crosslinkable functional group, a crosslinking agent (B), an ultraviolet-curable acrylate compound (C), a photopolymerization initiator (D), a silicone-based surface modifier (E) having a (meth)acryloyl group (or a silicone-based surface modifier (E') not having a (meth)acryloyl group), and a tin-based catalyst were adjusted to the formulation shown in Table 1 (the amount of the active ingredient is converted to active ingredient), and a coating liquid of the resin composition (active ingredient concentration: 10% by mass, diluent solvent: ethyl acetate) was applied to the easy-adhesion layer side of the substrate (Y) using a Meyer bar so that the film thickness after drying would be 1 μm. Next, by heating under conditions of 90 ° C. and 1 minute using a hot air dryer, the diluent solvent contained in the coating film formed by coating on the substrate (Y) was removed (drying process), and then ultraviolet light having a peak wavelength at a wavelength of 365 nm was applied to the substrate (Y) at an integrated light intensity of 150 mJ / cm ２ The coated sheet was then irradiated with ultraviolet light (ultraviolet curing step), and further left to stand for 7 days in an environment of 23°C and 50% relative humidity to allow crosslinking (crosslinking step). This formed an ink-receiving layer (X) with a thickness of 1 μm, and inkjet printing sheets of Examples 1 to 4 and Comparative Examples 1 to 5 were obtained. Next, an acrylic pressure-sensitive adhesive composition was applied to the release agent side of the release liner so that the film thickness after drying would be 20 μm, and the coating was heated at 90°C for 1 minute using a hot air dryer to remove the solvent contained in the acrylic pressure-sensitive adhesive composition, 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 (Y) opposite the ink-receiving layer (X), to obtain inkjet printing sheets of Examples 1 to 4 and Comparative Examples 1 to 5.

[0114] <Evaluation> (1-1) Evaluation of Latex Ink Adhesion (Dry) For each of the inkjet printing sheets of Examples 1 to 4 and Comparative Examples 1 to 5, a predetermined test pattern was printed on the surface of the ink-receiving layer (X) by an inkjet method using a latex ink (HP882, manufactured by Hewlett-Packard) with an inkjet printer (HP Latex R2000, manufactured by Hewlett-Packard), thereby forming a printed portion (printed layer). The inkjet printing sheets on which the predetermined test pattern was printed on the surface of the ink-receiving layer (X) were then left to stand for one day in an environment of 23°C and 50% relative humidity to prepare test samples. A 100 mm x 24 mm piece of Cellotape (registered trademark) manufactured by Nichiban Co., Ltd. was then attached to the side of the test sample on which the printed portion was formed. The remaining area of ​​the printed portion (remaining area / total area) after the tape was peeled off was determined and evaluated according to the following criteria. 1: Residual rate less than 20% 2: Residual rate 20% or more and less than 40% 3: Residual rate 40% or more and less than 60% 4: Residual rate 60% or more and less than 90% 5: Residual rate 90% or more The higher the residual rate, the better the ink adhesion of the ink-receiving layer (X). In this example, a rating of 3 or more was considered to be acceptable.

[0115] (1-2) Evaluation of UV-curable ink adhesion (Dry) A predetermined test pattern was printed on the surface of the ink-receiving layer (X) by the inkjet method using an inkjet printer (UCJV300, manufactured by Mimaki Engineering Co., Ltd.) with UV-curable ink (LUS-170, manufactured by Mimaki Engineering Co., Ltd.) to form a printed portion (printed layer). Then, the ink adhesion was evaluated in the same manner as in "(1-1) Evaluation of latex ink adhesion (Dry)".

[0116] (2-1) Evaluation of Water-Resistant Adhesion of Latex Ink For each of the inkjet printing sheets of Examples 1 to 4 and Comparative Examples 1 to 5, a predetermined test pattern was printed to form a printed portion (printed layer) in the same manner as in "(1-1) Evaluation of Latex Ink Adhesion (Dry)." Then, the inkjet printing sheets with the predetermined test pattern printed on the surface of the ink-receiving layer (X) were left to stand for one day in an environment of 23°C and 50% relative humidity to prepare test samples. A 3% by mass aqueous solution of an anionic surfactant (sodium laureth sulfate) was then sprayed onto the entire surface of the test sample on which the printed portion was formed, and the test sample was then left to stand for 10 minutes. The entire surface on which the printed portion was formed was then vigorously rubbed with a rubber squeegee to determine the remaining area of ​​the printed portion (remaining area / total area), and the results were evaluated according to the following criteria. 1: Residual rate less than 20% 2: Residual rate 20% or more and less than 40% 3: Residual rate 40% or more and less than 60% 4: Residual rate 60% or more and less than 90% 5: Residual rate 90% or more The higher the residual rate of the printed portion, the better the water-resistant adhesion of the ink-receiving layer (X). In this example, a rating of 3 or more was considered to be acceptable.

[0117] (2-2) Evaluation of Water-Resistant Adhesion of UV-Curable Ink For each of the inkjet printing sheets of Examples 1 to 4 and Comparative Examples 1 to 5, a predetermined test pattern was printed to form a printed portion (printed layer) in the same manner as in "(1-2) Evaluation of UV-Curable Ink Adhesion (Dry)". Then, the water-resistant adhesion of the UV-curable ink was evaluated in the same manner as in "(2-1) Evaluation of Latex Ink Adhesion".

[0118] (3) Evaluation of Blocking Resistance Each of the inkjet printing sheets of Examples 1 to 4 and Comparative Examples 1 to 5 was cut into a size of 5 cm x 10 cm and stacked to form a laminate. The laminate was sandwiched between 3 mm thick glass plates, and a 2 kg weight was placed on the glass plates. This laminate was then left to stand for 7 days in an environment of 40°C and 80% relative humidity. The laminate was then removed from between the glass plates and left to stand for 24 hours in an environment of 23°C and 50% relative humidity. The inkjet printing sheets were then peeled off one by one, and the peeling noise and adhesion were evaluated. The evaluation was performed according to the following criteria: 1: Very strongly adhered and unable to be peeled off; 2: Strongly adhered, loud peeling noise, or significant peeling marks; 3: Adhered, peeling noise, or faint peeling marks; 4: Adhered, but quiet peeling noise, or no peeling marks; 5: Not adhered. In this example, a rating of 4 or higher was considered acceptable.

[0119] The results are shown in Table 1.

[0120]

[0121] Table 1 reveals the following. It can be seen that the ink-receiving layers of the inkjet printing sheets of Examples 1 to 4 are excellent in ink adhesion, water-resistant ink adhesion, and blocking resistance. In contrast, it can be seen that water-resistant ink adhesion is not ensured in Comparative Examples 2 and 4, which do not contain the first ultraviolet-curable acrylate compound (C1). It can also be seen that blocking resistance is not ensured in Comparative Examples 3 and 5, which do not contain the second ultraviolet-curable acrylate compound (C2). Furthermore, it can be seen that blocking resistance is not ensured in Comparative Example 1, which does not contain the silicone-based surface modifier (E) that does not have a (meth)acryloyl group.

[0122] 1: Inkjet printing sheet; X: Ink receiving layer; Y: Substrate; Ya: One surface of the substrate; Yb: Other surface of the substrate; Z: Pressure-sensitive adhesive layer

Claims

1. A laminated structure in which an ink-receiving layer (X) and a substrate (Y) are laminated, wherein the ink-receiving layer (X) is formed from a resin composition (x1) containing an acrylic resin (A) having a crosslinkable functional group, a crosslinking agent (B), an ultraviolet-curable acrylate compound (C), a photopolymerization initiator (D), and a silicone surface modifier (E) having a (meth)acryloyl group, wherein the crosslinking agent (B) contains an isocyanurate compound (B1) having no (meth)acryloyl group, wherein the isocyanurate compound (B1) contains an isocyanurate compound (B1-1) and a modified isocyanurate compound (B1-2), wherein the isocyanurate compound (B1-1) is a trimer of 1,6-hexamethylene diisocyanate, and wherein the modified isocyanurate compound (B1-2) is a trimer of 1,6-hexamethylene diisocyanate and has one or more tertiary amino groups, The ultraviolet-curable acrylate compound (C) comprises a first ultraviolet-curable acrylate compound (C1) having a nurate skeleton and a second ultraviolet-curable acrylate compound (C2) not having a nurate skeleton.

2. The inkjet printing sheet according to claim 1, wherein the substrate (Y) contains a polyester resin.

3. The inkjet printing sheet according to claim 1 or 2, wherein the ink receiving layer (X) is laminated on one surface of the substrate (Y), and an adhesive layer (Z) is provided on the other surface of the substrate (Y).

4. The ink-jet printing sheet according to claim 3, wherein the adhesive surface of said adhesive layer (Z) is covered with a release liner.

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

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

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

Images