WO2016021655A1

WO2016021655A1 - Active energy beam-curable ink composition, laminate using this ink composition, and image forming-method of forming an image on a substrate

Info

Publication number: WO2016021655A1
Application number: PCT/JP2015/072272
Authority: WO
Inventors: 保真齋藤; 岳森山; 公淳宇高; 敏男古高
Original assignee: 株式会社Ｄｎｐファインケミカル
Priority date: 2014-08-08
Filing date: 2015-08-05
Publication date: 2016-02-11
Also published as: JP2016037583A; JP5800968B1

Abstract

　Provided is an ink composition that tracks a flexible substrate extremely well.　This active energy beam-curable ink composition contains, as active energy beam-polymerizable monomers, monomer A (a monofunctional monomer having a cyclic structure) and monomer B (a monomer having three or more functional groups, where the ratio of molecular weight/number of functional groups ≥ 200). The total content of monofunctional monomers including monomer A is at least 85.0mol%, and the content of monomer B is 0.5mol% to 10.0mol%.

Description

Active energy ray-curable ink composition, laminate using the ink composition, and image forming method for forming an image on a substrate

The present invention relates to an active energy ray-curable ink composition, a laminate obtained by printing the ink composition on a substrate having high flexibility at room temperature by an inkjet method, and an image formed on the substrate using the ink composition. The present invention relates to an image forming method for forming an uneven image, or an image and an uneven image.

Conventionally, development of an active energy ray-curable ink composition that is cured by ultraviolet rays, electron beams, or other active energy rays has been underway. Since the active energy ray-curable ink composition is quick-drying, it is possible to prevent ink bleeding even when printing on a substrate that does not absorb or hardly absorbs ink, such as plastic, glass, and coated paper. The active energy ray-curable ink composition is composed of a polymerizable monomer, a polymerization initiator, a pigment and other additives.

In recent years, printing is required not only when the base material is plastic, glass, coated paper, etc., but also when the base material is flexible, such as polyethylene terephthalate resin, vinyl chloride resin, and elastomer. In this case, since steps such as bending and pulling are included during thermoforming, the cured ink is required to have characteristics such as flexibility. Examples of such an active energy ray-curable ink composition include (A) an acrylate monomer having a glass transition point of 0 ° C. or less of a homopolymer of 20% by mass to 65% by mass in the reaction component, and (B) a fat The thing containing the monofunctional acrylate which has a cyclic structure, and the polyfunctional acrylate which has (C) alicyclic structure is proposed (refer patent document 1). A laminate in which this ink composition is printed on a polyethylene terephthalate resin and a vinyl chloride resin has excellent flexibility, elongation durability, abrasion resistance, and weather resistance, and is stretched and attached to an article having a curved surface such as a vehicle body. Even so, cracks and peeling do not occur because of the durability in the degree of elongation.

In addition to the polyethylene terephthalate resin and the vinyl chloride resin, the active energy ray-curable ink formed on the polycarbonate substrate satisfies the relationship between the predetermined elongation at break and the molecular weight between crosslinks in a 190 ° C. environment. An active energy ray curable ink has been proposed (see Patent Document 2).

JP 2011-162703 A Japanese Patent No. 4923523

In recent years, an active energy ray curable type suitable for a flexible base material that can be stretched from a low temperature to a high temperature, such as rubber, and that has a high elastic modulus (hereinafter sometimes simply referred to as an elastic base material). Ink development is desired. However, for example, the active energy ray curable ink according to Patent Document 2 is an active energy ray curable ink suitable for polycarbonate having lower flexibility and elasticity than an elastic base material such as rubber. Cannot be necessarily used for an elastic base material such as rubber. This is because the cured film used for the elastic base material having stretchability needs to be stretched following the same manner as the elastic base material, and it is necessary to use an active energy ray-curable ink that forms a highly stretchable cured film. . Further, even if the active energy ray-curable ink having stretchability is not scratch-resistant, scratches are generated, resulting in inferior design properties. May cause cracks. Therefore, development of an active energy ray-curable ink that forms a cured film having both stretchability and scratch resistance is strongly desired. However, since these are in a trade-off relationship, it is difficult to develop an active energy ray-curable ink having both stretchability and scratch resistance, and the fact is that it has not been developed yet.

The present invention has been made in view of the above circumstances, and the object of the present invention is that it can be applied to an elastic substrate such as an elastomer substrate, and has stretchability and scratch resistance. Is to provide an excellent active energy ray-curable ink composition.

In order to solve the above-mentioned problems, the present inventor has conducted intensive studies, and in the active energy ray-curable ink composition containing the active energy ray polymerizable monomer, examines the composition of the active energy ray polymerizable monomer. As a result, the inventors have found that the above problems can be solved, and have completed the present invention. Specifically, the present invention provides the following.

(1) As an active energy ray polymerizable monomer, the monomer A): a monofunctional monomer having a cyclic structure, and a monomer B): a trifunctional or higher functional monomer having a molecular weight / number of functional groups ≧ 200, the active energy ray In the total amount of polymerizable monomers, the total content of all monofunctional monomers including the monomer A) is 85.0 mol% or more, and the content of the monomer B) is 0.5 mol% or more and 10.0 mol% or less. An active energy ray-curable ink composition.

(2) The active energy ray-curable ink composition according to (1), wherein the content ratio of the monomer A) in the entire monofunctional monomer is 60.0 mol% or more and 100.0 mol% or less.

(3) The active energy ray-curable type according to (1) or (2), wherein the content of the monomer B) in the total amount of the active energy ray polymerizable monomer is 1.0 mol% or more and 7.0 mol% or less. Ink composition.

(4) The active energy ray-curable ink composition according to any one of (1) to (3), wherein the active energy ray polymerizable monomer contains a bifunctional monomer of monomer C: molecular weight / number of functional groups ≧ 200. .

(5) The active energy ray-curable ink composition according to (4), wherein the content of the monomer C) in the total amount of the active energy ray polymerizable monomer is 0.5 mol% or more and 5.0 mol% or less.

(6) The active energy ray-curable ink composition according to any one of (1) to (5), which is used as an inkjet ink.

(7) The active energy ray-curable ink composition according to any one of (1) to (6), wherein the monomer A) has a molecular weight of 1000 or less.

(8) The active energy ray-curable ink composition according to any one of (1) to (7), wherein the monomer B) has a molecular weight / functional group number of 250 or more and the monomer B) has a molecular weight of 750 or more. object.

(9) The active energy ray-curable ink composition according to (8), wherein the monomer B) has a molecular weight of 750 or more and 3000 or less.

(10) The active energy ray-curable ink composition according to any one of (1) to (9), wherein the monomer B) has a molecular weight / functional group number of 259 or more and the monomer B) has a molecular weight of 776 or more. object.

(11) The active energy ray-curable ink composition according to (10), wherein the monomer B) has a molecular weight of 776 to 2659.

(12) The active energy ray according to any one of (1) to (11), wherein the content of the monomer B) in the total amount of the active energy ray polymerizable monomer is 1.5 mol% or more and 10.0 mol% or less. A curable ink composition.

(13) The active energy ray-curable ink according to any one of (1) to (12), wherein the content ratio of the monomer A) in the entire monofunctional monomer is 80.0 mol% or more and 100.0 mol% or less. Composition.

(14) The monomer A) is benzyl acrylate, phenoxyethyl acrylate, isobornyl acrylate, 4-tert-butylcyclohexyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, γ-butyrolactone acrylate , Cresol acrylate, 2-acryloyloxyethyl phthalate, 2-acryloyloxyethyl-2-hydroxyethyl phthalate, 2-acryloyloxyethyl hexahydrophthalate, 2-acryloyloxypropyl phthalate, paracumylphenoxyethylene glycol acrylate, Nonylphenoxy polyethylene glycol acrylate, 1-adamantyl acrylate, cyclohexyl acrylate, Tet Group consisting of hydrofurfuryl acrylate, 3-3-5-trimethylcyclohexanol acrylate, 2-hydroxy-3-phenoxypropyl acrylate and (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate The active energy ray-curable ink composition according to any one of (1) to (13), wherein the ink composition is at least one or more selected monomers and may have alkoxy modification and caprolactone modification.

(15) A laminate in which an ink cured film layer that is a cured film of the active energy ray-curable ink composition according to any one of (1) to (14) is formed on a substrate.

(16) The laminate according to (15), wherein the base material is rubber.

(17) The active energy ray-curable ink composition is formed as a cured film having a thickness of 10 μm on a nitrile rubber (hereinafter referred to as “NBR”) sheet having a thickness of 1 mm, and the cured film is formed. When a film-forming substrate is tested as a dumbbell-shaped No. 6 (JIS K6251-5) test piece according to JIS K7161 method at 25 ° C. and a tensile rate of 100 mm / min, the cured film is cracked. The active energy ray-curable ink composition according to any one of (1) to (14), wherein the elongation at break of the film is 50% or more.

(18) The active energy ray-curable ink composition is formed as a cured film having a thickness of 10 μm on an NBR sheet having a thickness of 1 mm, and the elongation percentage of the cured film-forming substrate on which the cured film is formed is from 0%. When the expansion / contraction of the cured film-forming substrate is repeated 10 times at a strain rate of 100 mm / min so as to repeat the range up to 30%, cracks in the cured film are 3 or less (1) to (14 The active energy ray-curable ink composition according to any one of 1).

(19) An image, a concavo-convex image, or an image and a concavo-convex image on a substrate using the active energy ray-curable ink composition according to any one of (1) to (14), (17) or (18) Forming method.

According to the present invention, it is possible to provide an active energy ray-curable ink composition capable of achieving both stretchability and scratch resistance when formed as a cured film on a substrate.

Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and may be implemented with appropriate modifications within the scope of the object of the present invention. can do.

<Active energy ray-curable ink composition>
The active energy ray-curable ink composition of the present invention contains a monofunctional monomer A) having a cyclic structure and a tri- or higher functional monomer B) having “molecular weight / number of functional groups ≧ 200”. And the monofunctional monomer in the total amount of the active energy ray polymerizable monomer: 85.0 mol% or more, and the monomer B in the total amount of the active energy ray polymerizable monomer): 0.5 mol% or more and 10.0 mol% or less . Here, mol% means the percentage of the number of moles of a substance divided by the sum of the number of moles of all substances.

(Monofunctional monomer)
[Monomer A): Monofunctional monomer having a cyclic structure]
The monofunctional monomer is also referred to as monomer A) (hereinafter “monomer A)”. ) It has a ring structure. Monomer A) affects the curing by active energy rays, and has a cyclic structure, so that the curing rate can be increased more than when a non-cyclic monofunctional monomer having no cyclic structure is used. Become. As a result, compared with the case where an acyclic monofunctional monomer is used, since the curing proceeds more, the scratch resistance can be further improved.

As an example of the monomer A), the cyclic structure may be an aromatic ring, an aliphatic ring, or a heterocyclic ring. Specifically, benzyl acrylate, phenoxyethyl acrylate, isobornyl acrylate, 4-t-butylcyclohexyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, γ-butyrolactone acrylate, cresol acrylate 2-acryloyloxyethyl phthalate, 2-acryloyloxyethyl-2-hydroxyethyl phthalate, 2-acryloyloxyethyl hexahydrophthalate, 2-acryloyloxypropyl phthalate, paracumylphenoxyethylene glycol acrylate, nonylphenoxypolyethylene Glycol acrylate, 1-adamantyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl Acrylate, 3-3-5-trimethylcyclohexanol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate, alkoxy to these acrylates Examples thereof include those having various modifications such as modification and caprolactone modification, and (meth) acrylate, acryloylmorpholine, N-vinylcaprolactam, imide acrylate, and the like. Among them, since it has low viscosity and good curability, it has aromatic monofunctional monomers such as benzyl acrylate and phenoxyethyl acrylate, isobornyl acrylate, 4-t-butylcyclohexyl acrylate, cyclohexyl acrylate, and dicyclohexane. Selected from monofunctional monomers having an alicyclic structure such as pentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl acrylate, 3-3-5-trimethylcyclohexanol acrylate Any one or more monomers are preferable, and more preferable are aromatic monomers such as benzyl acrylate, isobornyl acrylate, and 4-t-butyl cyclohexyl. Sill acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, a monofunctional monomer having an alicyclic structure, such as 3-3-5- trimethyl cyclohexanol acrylate. By using benzyl acrylate, the composition can have a low viscosity while having an appropriate composition. By using a compound having an alicyclic structure, it is possible to improve the adhesion with a substrate described later. In particular, the combined use of benzyl acrylate and a monofunctional monomer having an alicyclic structure is particularly preferable because it can have both low viscosity and appropriate curability while also having good adhesion to a substrate. The molecular weight of monomer A) is preferably 1000 or less, more preferably 800 or less, and even more preferably 500 or less. By setting the molecular weight of the monomer A) to 1000 or less, the viscosity of the active energy ray-curable ink can be lowered, and the curing rate of the cured film formed from the active energy ray-curable ink composition is increased. The scratch resistance of the cured film can be improved.

[Other monofunctional monomers]
In the monofunctional monomer of the present invention, if the total of the monofunctional monomers contained in the active energy ray-curable ink composition is in the range of 85.0 mol% or more, isooctyl acrylate, tridecyl acrylate, lauryl are used as necessary. Acyclic monofunctional such as acrylate, 2-hydroxyethyl acrylate, stearyl acrylate, isodecyl acrylate, caprolactone acrylate, methoxypolyethylene glycol acrylate, methoxypolypropylene glycol acrylate, 2-methoxyethyl acrylate, ethyl carbitol acrylate, 2-ethylhexyl acrylate Monomers can also be added. When the total of monofunctional monomers is less than 85.0 mol%, there are too many polyfunctional monomers, the crosslink density is increased, the stretchability is lowered, and the viscosity of the active energy ray-curable ink itself is increased. This is not preferable because it becomes difficult when printing by this method.

The content of the monomer A) is a content ratio in the whole monofunctional monomer, and the monomer A) is 60.0 mol% or more and 100.0 mol% or less, and more preferably 80.0 mol% or more and 100.0 mol% or less. preferable. When the monomer A) having a cyclic structure is 60.0 mol% or more and 100.0 mol% or less, the curing rate can be further improved as compared with a non-cyclic monofunctional monomer. Therefore, the deterioration of scratch resistance due to insufficient curing can be prevented, and an excellent curable ink composition with improved scratch resistance can be obtained.

(Trifunctional or higher monomer)
[Monomer B): Monofunctional or higher-functional monomer with “molecular weight / number of functional groups ≧ 200”]
The active energy ray-polymerizable polyfunctional monomer is also referred to as monomer B): a tri- or higher functional monomer (hereinafter referred to as “monomer B)” having “molecular weight / number of functional groups ≧ 200”. ). Monomer B) contributes to improving scratch resistance while maintaining stretchability. In addition, by using monomer B), the coating film becomes tough and repeatability is improved. If the molecular weight / functional group ≧ 200 or more functional monomer, when the active energy ray-curable ink is cured, the scratch resistance can be improved by crosslinking, and a sufficient distance is secured between the crosslinking points. Can also be flexible. Therefore, by using the monomer B), both stretchability and scratch resistance can be improved. The molecular weight / number of functional groups of the monomer B) is preferably 230 or more and 600 or less, more preferably 250 or more and 600 or less, further preferably 259 or more and 600 or less, and 380 or more and 600 or less. Is even more preferred. When the molecular weight / functional group number is 230 or more, the stretchability and repeated stretchability of the cured film of the active energy ray-curable ink composition of the present invention can be improved. Since the molecular weight / number of functional groups is 600 or less, a sufficient crosslinking point in the cured film of the active energy ray-curable ink of the present invention can be secured, so that the scratch resistance of the cured film can be improved. .

Among monomers B), as an example of a trifunctional or higher functional monomer having “molecular weight / number of functional groups ≧ 200”, for example, ethylene oxide-modified (EO-modified) of trimethylolpropane triacrylate (9) (molecular weight = 692, number of functional groups = 3, molecular weight / functional group number = 231), EO modification (15) (molecular weight = 956, functional group number = 3, molecular weight / functional group number = 319), EO modification (20) (molecular weight = 1176, functional group number = 3, molecular weight / Functional group number = 392), EO modification (30) (molecular weight = 1616, functional group number = 3, molecular weight / functional group number = 539), propylene oxide modification (PO modification) (6) (molecular weight = 645, functional group number = 3, molecular weight / Functional group number = 215), for example EO modification of glycerol triacrylate (9) (molecular weight = 650, functional group number = 3, molecular weight / functional group number = 17), EO modification (20) (molecular weight = 1134, functional group number = 3, molecular weight / functional group number = 378), PO modification (6) (molecular weight = 602, functional group number = 3, molecular weight / functional group number = 201), PO Modification (9) (molecular weight = 776, functional group number = 3, molecular weight / functional group number = 259), eg EO modification of pentaerythritol tetraacrylate (35) (molecular weight = 1899, functional group number = 4, molecular weight / functional group number = 473) PO modification (10) (molecular weight = 932, functional group number = 4, molecular weight / functional group number = 233), dipentaerythritol hexaacrylate such as EO modification (18) (molecular weight = 1339, functional group number = 6, molecular weight / functional group number) = 223), EO modification (24) (molecular weight = 1603, functional group number = 6, molecular weight / functional group number = 267), EO modification (48) (molecular weight = 659, number of functional groups = 6, molecular weight / number of functional groups = 443), caprolactone modification (6) (molecular weight = 1231, number of functional groups = 6, molecular weight / number of functional groups = 205), caprolactone modification (12) (molecular weight = 1915, number of functional groups) = 6, molecular weight / number of functional groups = 319), and (meth) acrylates having different numbers of modifications, different types of modifications, and different structures. The molecular weight of the monomer B) is preferably 640 or more and 3000 or less, more preferably 750 or more and 3000 or less, further preferably 776 or more and 3000 or less, and even more preferably 1100 or more and 3000 or less. . The upper limit of the molecular weight of monomer B) is preferably 2659 or less. When the molecular weight of the monomer B) is 640 or more, the stretchability and repeated stretchability of the cured film of the active energy ray-curable ink composition of the present invention can be improved. Since the molecular weight of the monomer B) is 3000 or less, the crosslinking points in the cured film of the active energy ray-curable ink composition of the present invention can be sufficiently secured, and thus the scratch resistance of the cured film is improved. be able to.

The content of the monomer B) is 0.5 mol% or more and 10.0 mol% or less, more preferably 1.0 mol% or more and 7.0 mol% or less, based on the total amount of the active energy ray-curable monomer. Most preferably, it is 1.5 mol% or more and 5.0 mol% or less. If the amount is less than 0.5 mol%, the crosslinking density is not within the appropriate range due to the small number of crosslinking points or the short distance between the crosslinking points, making it difficult to balance stretchability and scratch resistance. Moreover, since crosslinking density will become high when it exceeds 10.0 mol%, stretchability falls and it becomes easy to enter a crack.

(Other monomers)
In the present invention, other monomers may be contained as long as the object of the present invention can be achieved. Examples of other monomers include polyurethane (meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate, and the like. Active energy ray-curable ink compositions containing monomers having a relatively high viscosity such as these acrylates have high overall ink viscosity. For example, when ejected using an ink jet apparatus, depending on the ejection pressure May be difficult to discharge. Therefore, when these acrylates are contained, it is preferable that these acrylates are included in an amount of 10.0% by mass or less, and more preferable that 5.0% by mass or less are included with respect to the total amount of monomers. More preferably, it is not included in. “Substantially not included” means that other monomers are 1.0% by mass or less based on the total amount of monomers. Here, the monomer in the present invention is a concept including a compound also called an oligomer or a prepolymer depending on the molecular weight.

Further, for example, in addition to the acrylate, a conventionally known bifunctional monomer or a trifunctional or higher monomer other than the monomer B) having a molecular weight / functional group number of less than 200 may be included as other monomers. . As a bifunctional monomer, for example, 1,6-hexanediol diacrylate is not modified (molecular weight = 226, molecular weight / functional group number = 113), EO modified (2) (molecular weight = 314, molecular weight / functional group number = 157), EO modified. (3) (molecular weight = 358, molecular weight / functional group number = 179), EO modification (5) (molecular weight = 446, molecular weight / functional group number = 223), PO modification (2) (molecular weight = 342, molecular weight / functional group number = 171) ), PO modification (3) (molecular weight = 400, molecular weight / number of functional groups = 200), for example, no modification of neopentyl glycol diacrylate (molecular weight = 212, molecular weight / functional group number = 106), PO modification (8) (molecular weight = 676, molecular weight / functional group number = 338), PO modification (16) (molecular weight = 1140, molecular weight / functional group number = 570), hydroxypivalic acid ne For example, no modification of pentyl glycol diacrylate (molecular weight = 326, molecular weight / functional group number = 163), caprolactone modification (2) (molecular weight = 554, molecular weight / functional group number = 277), caprolactone modification (4) (molecular weight = 782, molecular weight) / Functional group number = 391), for example, EO modification (2) of polyalkylene glycol diacrylate (molecular weight = 214, molecular weight / functional group number = 107), EO modification (3) (molecular weight = 258, molecular weight / functional group number = 129), EO modification (4) (molecular weight = 302, molecular weight / functional group number = 151), EO modification (9) (molecular weight = 508, molecular weight / functional group number = 254), EO modification (14) (molecular weight = 742, molecular weight / functional group number) = 371), EO modification (23) (molecular weight = 1138, molecular weight / functional group number = 569), EO modification (46) ( Molecular weight = 2150, molecular weight / functional group number = 1075), PO modification (2) (molecular weight = 242, molecular weight / functional group number = 121), PO modification (3) (molecular weight = 300, molecular weight / functional group number = 150), PO Modification (7) (molecular weight = 532, molecular weight / functional group number = 266), PO modification (12) (molecular weight = 822, molecular weight / functional group number = 411), PO modification (12) & EO modification (6) (molecular weight = 1086, Molecular weight / number of functional groups = 543), PO modified (6) & EO modified (12) (molecular weight = 1002, molecular weight / functional group = 501), PO modified (4) & EO modified (12) (molecular weight = 886, molecular weight / functional group number) = 443), PO modification (4) & EO modification (17) (molecular weight = 1106, molecular weight / functional group number = 553), PO modification (13) & EO modification (5) (molecular weight = 3124, molecular weight / Functional group number = 1562), butylene oxide modification (BO modification) (3.5) (molecular weight = 378, molecular weight / functional group number = 189), BO modification (9) (molecular weight = 774, molecular weight / functional group number = 387), BO Modification (14) (molecular weight = 1134, molecular weight / number of functional groups = 567), eg EO modification of alkoxylated bisphenol A diacrylate (2) (molecular weight = 424, molecular weight / functional group number = 212), EO modification (3) (molecular weight = 468, molecular weight / functional group number = 234), EO modification (4) (molecular weight = 512, molecular weight / functional group number = 256), EO modification (10) (molecular weight = 776, molecular weight / functional group number = 388), EO modification ( 20) (molecular weight = 1216, molecular weight / functional group number = 608), EO modification (30) (molecular weight = 1656, molecular weight / functional group number = 828), PO modification ( ) (Molecular weight = 510, molecular weight / functional group number = 255), PO modification (6) & EO modification (3) (molecular weight = 816, molecular weight / functional group number = 408) For example, modification of trimethylolpropane triacrylate as a trifunctional monomer None (molecular weight = 296, molecular weight / functional group number = 99), EO modification (3) (molecular weight = 428, molecular weight / functional group number = 143), EO modification (6) (molecular weight = 560, molecular weight / functional group number = 187), PO modification (3) (molecular weight = 470, molecular weight / number of functional groups = 157), eg EO modification of glycerol triacrylate (3) (molecular weight = 386, molecular weight / functional group number = 129), EO modification (6) (molecular weight = 518) , Molecular weight / number of functional groups = 173), PO modification (3) (molecular weight = 428, molecular weight / number of functional groups = 143), PO modification (5.5) (molecular weight 573, molecular weight / number of functional groups = 191), pentaerythritol triacrylate, for example, no modification (molecular weight = 298, molecular weight / functional group number = 99)), as tetrafunctional monomer, pentaerythritol tetraacrylate, for example, no modification (molecular weight = 352, Molecular weight / functional group number = 88), EO modification (4) (molecular weight = 528, molecular weight / functional group number = 132), PO modification (4) (molecular weight = 584, molecular weight / functional group number = 146), ditrimethylolpropane tetraacrylate For example, no modification (molecular weight = 482, molecular weight / functional group number = 121), EO modification (4) (molecular weight = 658, molecular weight / functional group number = 165), PO modification (4) (molecular weight = 714, functional group number = 4, Molecular weight / number of functional groups = 179) Dipentaerythritol pentaa as a pentafunctional monomer For example, no modification (molecular weight = 525, molecular weight / number of functional groups = 105) of acrylate, dipentaerythritol hexaacrylate, for example, as a hexafunctional monomer, no modification (molecular weight = 547, molecular weight / number of functional groups = 91), EO modification ( 6) (molecular weight = 811, molecular weight / functional group number = 135), EO modification (12) (molecular weight = 1075, molecular weight / functional group number = 179), PO modification (6) (molecular weight = 895, functional group number = 6, molecular weight / Functional group number = 149), caprolactone modification (2) (molecular weight = 775, functional group number = 6, molecular weight / functional group number = 129), caprolactone modification (3) (molecular weight = 889, functional group number = 6, molecular weight / functional group number = 148) ), And their modified number, modified species, structural difference (meth) acrylate, urethane acrylate, epoxy Rate, polyester acrylate. Among them, bifunctional monomers satisfying “molecular weight / number of functional groups ≧ 200” are used as the third component in addition to the monomers A) and B), so that the crosslinking density is reduced and stretchability (especially stretch at 0 ° C. or lower). Is particularly preferable in that it can be further improved. In addition, the monomer in this invention is the concept also including the compound also called an oligomer depending on the molecular weight.

In the active energy ray-curable ink composition of the present invention, the total amount of all monofunctional monomers, monomer B, and other monomers is preferably 80.0% by mass or more based on the total amount of monomers, 90.0 More preferably, it is more than 10 mass%, and it is preferable that it is substantially 100.0 mass%. Here, substantially 100.0 mass% means that the total amount of monomer A, monomer B and other monomers is 99.0 mass% or more with respect to the total amount of monomers.

In particular, among the bifunctional monomers, the monomer C) of “molecular weight / functional group ≧ 200” is 0.5 mol% or more and less than 5.0 mol%, more preferably 1.3 mol% or more and 3.0 mol% or less, More preferably, the active energy ray-polymerizable curable ink composition contained in an amount of 1.5 mol% or more and 2.6 mol% or less can relax the crosslink density within a range in which scratch resistance can be maintained, and thus more stretched. Can be improved. In particular, it can be preferably used in a use environment that requires stretchability. The molecular weight / functional group number of the monomer C) is preferably 1750 or less. Since the molecular weight / number of functional groups is 1750 or less, a sufficient crosslinking point in the cured film of the active energy ray-curable ink of the present invention can be secured, so that the scratch resistance of the cured film can be improved. . The molecular weight of the monomer C is preferably 400 or more and 3500 or less. When the molecular weight of the monomer C) is 400 or more, the stretchability and repeated stretchability of the cured film of the active energy ray-curable ink composition of the present invention can be improved. When the molecular weight of the monomer C) is 3500 or less, a sufficient crosslinking point in the cured film of the active energy ray-curable ink composition of the present invention can be secured, and the scratch resistance of the cured film is maintained. Can do.

The active energy ray curable ink composition having a specific amount of monomers A) and B) according to the present invention has a trifunctional or higher polyfunctional monomer component compared to the conventional ink composition as compared with the conventional active energy ray curable ink. Many are included in comparison. Moreover, when the monomer has a high molecular weight / number of functional groups and is cured, the polyfunctional monomers having a long distance between double bonds are polymerized and crosslinked. As a result, the distance between crosslinks is increased as compared with the conventional active energy ray curable ink. Therefore, it is possible to obtain an active energy ray-curable ink excellent in stretchability that follows and stretches the elastic substrate during stretching. In addition, by using a polyfunctional monomer having a tri- or higher functional monomer in this way, it is possible to secure a certain number of cross-linking points while maintaining a long distance between the cross-linking points. As a result, an active energy ray-curable ink having both stretchability and scratch resistance can be obtained.

In addition, in this invention, you may further contain the polymer component which does not have reactivity. Examples of such polymer components include acrylic resins and cellulose acetate butyrate resins.

[Active energy ray polymerization initiator]
The active energy ray-curable ink composition may contain an active energy ray polymerization initiator as necessary. Active energy rays are energy rays that can trigger polymerization reactions such as radicals, cations, and anions. In addition to rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, and infrared rays, electromagnetic waves such as X-rays and γ rays, electron beams Any of proton beam, neutron beam and the like may be used, but curing by ultraviolet irradiation is preferable from the viewpoints of curing speed, availability of an irradiation apparatus, price, and the like. The active energy ray polymerization initiator is not particularly limited as long as it accelerates the polymerization reaction of the compound having an ethylenically unsaturated double bond in the active energy ray-curable ink composition by irradiation with active energy rays, Conventionally known active energy ray polymerization initiators can be used. Specific examples of the active energy ray polymerization initiator include, for example, aromatic ketones containing thioxanthone, α-aminoalkylphenones, α-hydroxyketones, acylphosphine oxides, aromatic onium salts, organic peroxides Thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon halogen bond, and alkylamine compounds.

The amount of the active energy ray polymerization initiator may be an amount capable of appropriately starting the polymerization reaction of the active energy ray polymerizable monomer, and is 1% by mass or more and 20% by mass or less based on the entire active energy ray curable ink composition. It is preferable that it is 3 mass% or more and 20 mass% or less. In the present invention, the active energy ray polymerization initiator is not necessarily required. For example, when an electron beam is used as the active energy ray, the active energy ray polymerization initiator may not be used.

[Color material]
The active energy ray-curable ink composition of the present invention may contain a coloring material as necessary. By containing a coloring material, a cured film can be preferably used as a cured film (decorative layer) for decoration. The coloring material may be any inorganic pigment or organic pigment that is usually used in conventional oil-based ink compositions, such as carbon black, cadmium red, molybdenum red, chrome yellow, and cadmium yellow. , Titanium yellow, titanium oxide, chromium oxide, viridian, titanium cobalt green, ultramarine blue, Prussian blue, cobalt blue, diketopyrrolopyrrole, anthraquinone, benzimidazolone, anthrapyrimidine, azo pigment, phthalocyanine pigment, quinacridone Pigment, isoindolinone pigment, dioxazine pigment, selenium pigment, perylene pigment, perinone pigment, thioindigo pigment, quinophthalone pigment, metal complex pigment, aluminum paste, silica, calcium carbonate, magnesium carbonate Beam, clay, precipitated barium sulfate, pearl pigments, and the like.

The preferable dispersed particle diameter of the pigment of the active energy ray-curable ink composition is preferably 10 nm or more and 300 nm or less in terms of a volume average particle diameter by a laser scattering method. When the volume average particle size is 10 nm or more and 300 nm or less, light resistance can be maintained, dispersion can be stabilized, and pigment sedimentation or when inkjet ink is ejected by an inkjet recording apparatus. Since it is possible to reduce the possibility of occurrence of head clogging or ejection bending, a more preferable curable ink can be obtained.

In the present invention, when a pigment is used, its content may be appropriately adjusted. Although different depending on the type of pigment, the content of the pigment in the entire inkjet ink composition is preferably 0.1% by mass or more and 20% by mass or less in the case of an organic pigment from the viewpoint of achieving both dispersibility and coloring power. 0.2 mass% or more and 10 mass% or less are more preferable. Moreover, from the point which balances dispersibility and coloring power, in the case of an inorganic pigment, 1 mass% or more and 40 mass% or less are preferable, and 5 mass% or more and 20 mass% or less are more preferable.

[Matte material]
The active energy ray-curable ink composition of the present invention may contain a matte material, if necessary. As the matting agent, for example, various powders such as silica, alumina, calcium carbonate and the like can be used. Matting agents may be used alone or in combination of two or more.

[Dispersant]
The active energy ray-curable ink composition may contain a dispersant as necessary. Examples of the dispersant include a polymer dispersant. The main chain of this polymer dispersant is made of polyester, polyacrylic, polyurethane, polyamine, polycaprolactone, etc., and the polymer dispersant has amino groups, carboxyl groups, sulfone groups, hydroxyl groups, etc. as side chains. It is preferable to have a polar group or a salt thereof.

A preferred polymer dispersant is a polyester-based dispersant. Specific examples thereof include “SOLPERSE 33000” and “SOLPERSE 32000” and “SOLPERSE 24000” manufactured by Lubrizol Japan; “Dispersbyk 168” manufactured by BYK Chemie; Etc.

[Surface conditioner]
The active energy ray-curable ink composition may further contain a surface conditioner. The surface conditioning agent is not particularly limited, but specific examples include “BYK-306”, “BYK-333”, “BYK-371”, “BYK-377”, Evonik Degussa Japan, manufactured by BYK Chemie having dimethylpolysiloxane. “TegoRad2100”, “TegoRad2200N”, “TegoRad2300” and the like manufactured by the company can be mentioned.

The content of the surface conditioner is preferably 0.1% by mass or more and 5.0% by mass or less with respect to the total amount of the ink composition. By setting the content to 0.1% by mass or more and 5.0% by mass or less, the ink composition has preferable wettability with respect to the thermoplastic resin substrate and the like, and the active energy ray curable type is used when printing on the substrate. Since the ink composition can spread and spread without causing repelling, a particularly preferable active energy ray-curable ink composition can be obtained.

[Other additives]
The active energy ray-curable ink composition may contain various additives such as a plasticizer, a polymerization inhibitor, a light stabilizer, and an antioxidant as other additives. The solvent can be added within a range that achieves the object of the present application.

[viscosity]
The viscosity of the active energy ray-curable ink composition is preferably 5 mPa · s to 30 mPa · s at 40 ° C., more preferably 5 mPa · s to 20 mPa · s. When it is set to 5 mPa · s or more and 30 mPa · s or less, it becomes possible to maintain a preferable discharge property when discharging using an ink jet apparatus, so that a more preferable active energy ray-curable ink composition is obtained. be able to. Here, the ejection property means the frequency of occurrence of missing ink dots during continuous printing, the accuracy of printing due to the occurrence of ejection disturbance, and the like.

In addition, the surface tension of the active energy ray-curable ink composition of the present invention is such that the surface tension at 40 ° C. is 20 mN / m or more and 40 mN / m or less from the viewpoint of inkjet dischargeability and discharge stability. preferable.

<Method for producing active energy ray-curable ink composition>
The method for producing the active energy ray-curable ink composition of the present invention is not particularly limited, and a conventionally known method can be used. Moreover, when using a granular coloring material, a granular matting agent, etc., it disperse | distributes with an active energy ray polymerizable monomer, a dispersing agent, etc. using a disperser, and then an active energy ray polymerization initiator as needed. The active energy ray-curable ink composition of the present invention is obtained by adding a surface conditioner and the like, stirring uniformly, and further filtering through a filter.

<Method for producing laminate>
The laminate of the present invention is produced by printing the active energy ray-curable ink composition on a substrate, preferably by an ink jet method, and then curing with an active energy ray. The printing can be performed by a conventionally known method such as an offset printing method, a gravure printing method, a spray method, or a brush coating method, but an inkjet method is preferable in that it can cope with a wide variety of small lots. An image can be formed on the substrate using the active energy ray-curable ink composition. For example, by preparing an ink set of an active energy ray-curable ink composition prepared using dispersions in which color materials of various shades are dispersed, and printing by an ink jet method, the ink composition is cured, Various images can be formed on the substrate. An active energy ray-curable ink composition for forming such a cured film and an image forming method for forming an image on a substrate are also within the scope of the present invention.

[Base material]
The substrate is not particularly limited, but a substrate having elasticity is desirable. As the elastic substrate, rubber or elastomer resin can be preferably used. As the elastomer resin, for example, a thermoplastic elastomer (hereinafter also referred to as “TPE”) can be preferably used. TPE refers to a polymer material that is plasticized at a high temperature and can be injection-molded and processed like a plastic and exhibits properties of a rubber elastic body (elastomer) at room temperature.

The TPE molecule may be a block polymer type in which a hard segment (plastic component) and a soft segment (elastic component) are chemically bonded in a single polymer, or a blend in which a hard segment and a soft segment are physically mixed. It may be a mold. Examples of TPE molecules include styrene, olefin, polyurethane and the like.

Examples of styrene-based materials include NBR (nitrile rubber), SBS (styrene / butadiene / styrene block copolymer), SEBS (styrene / ethylene / butylene styrene block copolymer), and SEPS (styrene / ethylene / propylene / styrene block copolymer). Polymer) and the like. An example of the olefin type is TPO (thermoplastic olefin) in which ethylene-propylene rubber is finely dispersed in polypropylene. Further, examples of the polyurethane system include thermoplastic polyurethane (hereinafter also referred to as “TPU”). Among them, it is preferable to use NBR (nitrile rubber) from the viewpoint of wear resistance and aging resistance.

Since the present invention is an active energy ray-curable ink that forms a cured film having excellent scratch resistance and stretchability even if the substrate is an elastic substrate, even if the substrate is repeatedly expanded and contracted Further, it is characterized in that cracking or peeling of the cured film formed on the surface can be effectively suppressed.

[Curing with active energy rays]
The active energy ray is preferably light having a wavelength range of 200 nm to 450 nm, and more preferably light having a wavelength range of 250 nm to 430 nm. The light source is not particularly limited, and examples thereof include a high pressure mercury lamp, a metal halide lamp, a low pressure mercury lamp, an ultrahigh pressure mercury lamp, an ultraviolet laser, sunlight, and an LED lamp. By using these light sources and irradiating active energy rays so that the integrated light quantity is 100 mJ / cm 2 or more, preferably 200 mJ / cm 2 or more, the ink composition can be cured instantaneously.

The thickness of the cured film obtained by curing the active energy ray-curable ink composition of the present invention (hereinafter referred to as “cured film”) is preferably 1 μm or more and 100 μm or less. By setting the thickness to 1 μm or more, the color density of the cured film containing the coloring material does not become thin, so that the physical properties such as a decrease in design properties, decorativeness, adhesion, and extensibility are improved. By setting the thickness to 100 μm or less, the ink composition can be sufficiently cured in a shorter time when the ink composition is irradiated with active energy rays, which is more preferable.

The cured film thickness is measured by applying an ink composition to a PET film (A4300, manufactured by Toyobo Co., Ltd.) under the same coating conditions as the prepared cured film, and measuring the thickness of the obtained cured film with a micrometer. did. The measurement was performed at 10 points per sample, and the average value of these was taken as the average film thickness. The same applies to the protective layer and primer described later.

The active energy ray-curable ink composition of the present invention is formed as a cured film having a thickness of 10 microns on an NBR sheet having a thickness of 1 mm, and a cured film-forming substrate on which the cured film is formed is dumbbell-shaped No. 6. As a test piece of the shape (JIS K6251-5), the minimum elongation when cracking of the cured film occurs when a tensile test is performed at 25 ° C. and a tensile speed of 100 mm / min according to JIS K7161 method is the elongation at break of the cured film. As defined, the elongation at break of the cured film is preferably 50% or more (for example, the elongation when the base material is stretched twice the original is expressed as 100%) or more, and preferably 100% or more. More preferably, it is preferably 1000% or less. The elongation at break of the cured film is 50% or more, so that it can sufficiently follow the elongation of the substrate, and even when the substrate expands and contracts, the cured film formed on the surface is cracked or peeled off. Can be further suppressed. On the other hand, when the elongation at break of the cured film exceeds 1000%, it is difficult to increase the strength of the cured film.

Further, the active energy ray-curable ink composition of the present invention is formed as a cured film having a thickness of 10 μm on a 1 mm thick NBR sheet, and the elongation percentage of the cured film-forming substrate on which the cured film is formed is 0%. Even if the expansion / contraction of the cured film-forming substrate is repeated 10 times at a strain rate of 100 mm / min so as to repeat the range from 1 to 30%, the cured film does not crack. Therefore, it is possible to sufficiently follow the expansion and contraction of the base material, and even when the base material expands and contracts, cracking and peeling of the cured film formed on the surface can be suppressed.

[Curing film]
The cured film formed from the active energy ray-curable ink composition of the present invention can be used as a decorative layer as long as it contains a coloring material as described above, but it can be added without adding a coloring material. If it discharges on a decoration layer, this cured film itself can also be utilized as an overcoat layer which protects a cured film. Furthermore, it can utilize also as a primer layer for improving both adhesiveness by forming between a base-material surface and a cured film. An active energy ray-curable ink composition that forms such a cured film is also within the scope of the present invention.

The active energy ray-curable ink composition of the present invention may be used to form a decorative layer, an overcoat layer, or a primer layer independently only with a cured film formed by the active energy ray-curable ink composition of the present invention. Or a combination of these layers. For example, the active energy ray-curable ink composition of the present invention in which a coloring material is added to the active energy ray-curable ink composition of the present invention to form a decorative layer, and no coloring material is added on the decorative layer. An overcoat layer can also be formed by discharging. Moreover, the cured film formed with the active energy ray-curable ink composition of the present invention can also be used in combination with a decorative layer, overcoat layer or primer layer formed with a conventionally known ink composition. For example, when the active energy ray-curable ink composition of the present invention is used as a decorative layer, an overcoat layer can be formed on the decorative layer using a conventionally known overcoat composition.

The thickness of the decorative layer is preferably 1 μm or more and 100 μm or less. By setting the thickness to 1 μm or more, the color density of the decorative layer becomes appropriate, the design properties and decorative properties are improved, and physical properties such as adhesion and extensibility are improved. A thickness of 100 μm or less is preferable because the ink composition can be sufficiently cured in a short time when the ink composition is irradiated with active energy rays.

When forming an overcoat layer or primer layer on a substrate, any method may be used to form these layers, for example, spray coating, towel, sponge, non-woven fabric, tissue-based coating, etc. , Dispenser, brush coating, gravure printing, flexographic printing, silk screen printing, ink jet, thermal transfer method, etc. may be used.

[Overcoat layer]
For the purpose of further improving the durability of the laminate, an overcoat layer comprising a conventionally known overcoat agent or the ink composition of the present invention is used as an overcoat agent on the surface of the cured film of the ink composition of the present invention. An overcoat layer formed by use may be further formed. The overcoat layer is not limited to being formed on the surface of the layer made of the cured film of the ink composition, but may be directly formed on the surface of the substrate, or may be formed on the surface of the substrate. You may form in the surface of the primer layer mentioned later.

As the overcoat agent, the active energy ray-curable ink composition of the present invention can be preferably used. By using the active energy ray-curable ink composition of the present invention, excellent stretchability and scratch resistance can be realized. Further, for example, when an overcoat layer is formed with an overcoat agent using the active energy ray-curable ink composition of the present invention on a cured film using the active energy ray-curable ink composition of the present invention, the curing is performed. Since the film and the overcoat layer have the same composition, their adhesion is extremely high. Therefore, it is particularly preferable to use the active energy ray-curable ink composition of the present invention as an overcoat agent for the cured film of the active energy ray-curable ink composition of the present invention.

The thickness of the overcoat layer is preferably 1 μm or more and 100 μm or less. Since it can protect a decoration layer appropriately by setting it as 1 micrometer or more, it is preferable. Moreover, it is preferable for the thickness to be 100 μm or less because the drying time can be shortened to form an overcoat layer and the productivity can be improved.

Moreover, as a conventionally well-known overcoat agent, since it is excellent in the followability to a base material, scratch resistance, chemical resistance, etc., the Tg which made the active ingredient amount 20% or more and less than 60% is 50 ° C. or less. A composition containing a modified (meth) acrylic emulsion can also be used. OP-11, OP-13, OP-39, OP-53, OP-55 (all manufactured by DNP Fine Chemical Co., Ltd.) are commercially available resin compositions for forming an overcoat layer containing a silicone-modified (meth) acrylic emulsion. Is mentioned. Since the Tg of the silicone-modified (meth) acrylic emulsion containing any of these is 50 ° C. or less, the elongation of the cured film is good. Moreover, it has a high followability to the substrate even under conditions where repeated stress is applied.

Further, when the overcoat layer is formed, the design property is imparted to the overcoat layer by adjusting the discharge amount of the ink composition and the conditions such as the time from the discharge of the ink composition to the irradiation of the active energy ray. You can also For example, it is also possible to form a three-dimensional and highly designed overcoat layer with irregularities by making the surface matt or glossy, or by making the surface film thickness non-uniform. Specifically, after discharging the ink composition, the surface can be made glossy by irradiating active energy rays after a predetermined time has elapsed, and the surface can be quickly irradiated by irradiating active energy rays after discharging. It can be matte. Further, unevenness can be imparted by increasing / decreasing the discharge amount per time depending on the discharge location, and unevenness difference from other locations by repeating the ejection of the ink composition and the irradiation of the active energy ray at the same location. Can also be given. An active energy ray-curable ink composition for forming such a cured film and an image forming method for forming an uneven image are also within the scope of the present invention. Such an overcoat layer is desirably formed by an ink jet method from the viewpoint of easy condition adjustment.

[Primer layer]
A primer formed with a conventionally known primer for the purpose of improving the adhesion between layers (for example, a base layer and a decorative layer, a base layer and an overcoat layer, and a decorative layer and an overcoat layer). A layer or a cured film formed from the ink composition of the present invention may be provided as a primer layer. For example, a cured film using the active energy ray-curable ink composition of the present invention is formed as a primer layer with the active energy ray-curable ink composition of the present invention when a decorative layer and / or an overcoat layer is formed. In this case, since the cured film and the primer layer have the same composition, their adhesion is extremely high. Therefore, it is particularly preferable to use the active energy ray-curable ink composition of the present invention as a primer agent.

As a conventionally well-known primer agent, 10 mass% or more and less than 80 mass% are preferable as an active ingredient amount of a silicone modified (meth) acrylic-type emulsion with respect to the whole primer agent, 20 mass% or more and less than 60 mass% are preferable. More preferred. By setting it as 10 mass% or more, in order to form a primer layer, it is preferable at the point which productivity improves from the point of drying time. By making it less than 80 mass%, it is preferable at the point which becomes easy to apply | coat a primer agent.

Examples of the curing agent include polyisocyanate. It is preferable that content of a hardening | curing agent is 1 to 50 mass parts with respect to 100 mass parts of primer agents. By setting it as 1 mass part or more, even if it adds a hardening | curing agent, it is preferable at the point which adhesiveness improves significantly. Since the followability to a base material improves by setting it as 50 mass parts or less, it is preferable.

A primer agent having a concealing property can be obtained by adding a concealing pigment to the primer agent. By using a primer agent having a concealing property, for example, when the base material is colored, the base material color can be concealed, so that the design and color development can be improved when the decorative layer is formed. . Conventionally known hiding pigments can be used as the hiding pigment, and for example, white pigments such as titanium oxide, hiding pigments such as aluminum paste and pearl pigments can be used. In particular, a primer agent containing titanium oxide is preferable in order to improve the designability and color developability of the decorative layer.

When the primer agent contains titanium oxide, the content of titanium oxide is preferably 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the primer agent. By setting it as 1 mass part or more, the designability and coloring property after printing improve significantly. By setting it to 50 parts by mass or less, the followability of the cured film is improved.

The thickness of the primer layer is preferably 1 μm or more and 100 μm or less. By making the thickness 1 μm or more, the adhesion between the tire surface and the decorative layer is significantly improved, and in the case of a primer layer containing a concealing pigment, the design and color development properties after printing the decorative layer are significantly improved. This is preferable because it can be performed. Moreover, it is preferable for the thickness to be 100 μm or less because the drying time can be shortened to form an overcoat layer and the productivity can be improved.

Examples of commercially available primer agents include PR-12 and PR-13 (both manufactured by DNP Fine Chemical Co.) containing titanium oxide and silicone-modified (meth) acrylic emulsion.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these descriptions.

<Preparation of ink composition (Examples 1 to 10, Comparative Examples 1 to 4)>
Table 1 shows the number of moles of each monomer in 100 g of the ink composition in Examples, and Table 2 shows mol% of each monomer in the total amount of monomers of the ink composition in Examples.

(Unit is mol)

(Unit: mol%)

Table 3 shows the mol number of each monomer in 100 g of the ink composition in the comparative example, and Table 4 shows mol% of each monomer in the total amount of the monomer in the ink composition in the comparative example.

(Unit is mol)

(Unit: mol%)

Table 5 and Table 5 show the mol% of the total amount of monomer A, the mol% of the total amount of monomer B, and the mol% of the total amount of monomer A in all monofunctional monomers in the total amount of all the monomers of the ink compositions in Examples and Comparative Examples. It is shown in FIG.

(Unit: mol%)

(Unit: mol%)

[Preparation of ink composition]
A dispersion is prepared by dispersing 12% by mass of titanium oxide as a pigment and a polymer dispersant in the monomer so that the active ingredient is 8% by mass with respect to the pigment, and the ratio is as shown in Tables 1 to 6. A monomer was further mixed with 10% by mass of 2,4,6-trimethylbenzoyldiphenylphosphine oxide as a photoinitiator, and 0.05% by mass of phenothiazine as a polymerization inhibitor. The mixture was stirred for 1 hour while warming. Then, after confirming that there was no undissolved residue and returning to room temperature, a dispersion prepared in advance was added and stirred for 1 hour. Thereafter, filtration was performed using a membrane filter, and ink compositions of Examples 1 to 10 and Comparative Examples 1 to 4 were prepared.

<Manufacture of laminates (Examples 1 to 10, Comparative Examples 1 to 4)>
A laminate was produced using NBR as a base material. Each sample was produced on the surface of the substrate by the inkjet method. Then, using a SubZero system (UV lamp system, manufactured by Integration Technology, D bulb, output 100 W / cm), ink is used under the conditions of an integrated light quantity of 900 mJ / cm2, a peak illuminance of 640 mW / cm2, and a conveyance speed of 18 m / min. The composition was cured. The accumulated light amount and peak illuminance were measured using an ultraviolet light meter UV-351 (manufactured by Oak Manufacturing Co., Ltd.). Thereby, the decoration layer was produced.

[Evaluation of stretchability]
Using the laminates of Examples and Comparative Examples as dumbbell-shaped No. 6 type (JIS K6251-5) test pieces, the range of elongation from 0% to 100% was measured at 25 ° C., and the expansion and contraction of the laminate was 100 mm / min. It was confirmed whether or not the cured film was cracked when stretched once at a speed. The elongation percentage was calculated from (the length of the laminate when cracking of the cured film occurred−the original length of the laminate) / the original length of the laminate × 100. The results are shown in Tables 7 and 8. Even when the elongation rate was 100%, when there were less than 3 cracks, it was marked “◎”. When the elongation rate was 50 to 100%, there were less than 3 cracks. “O” was defined as “とき”, and “x” was defined when the number of substantial cracks was 3 or more when the elongation was 50%. Here, the substantial crack means a crack in which a crack (crack) has progressed by 50% or more with respect to the length of the sample piece width.

[Evaluation of repeated stretchability]
Using the laminates of Examples and Comparative Examples as test pieces of dumbbell shape No. 6 (JIS K6251-5), the elongation of the laminate was set at a strain of 100 mm / min in the range from 0% to 30% at 25 ° C. It was confirmed whether or not the cured film was cracked when stretched 10 times at a speed. The elongation percentage was calculated from (the length of the laminate when cracking of the cured film occurred−the original length of the laminate) / the original length of the laminate × 100. The results are shown in Tables 7 and 8. When the crack of the cured film did not occur, “◯” was given. When there was a crack in a very small part, the number of substantial cracks was 3 or less, and when the crack was substantially within the allowable range, “△”. When the crack or peeling was observed and the value substantially exceeded the allowable range, “x” was given. Here, the substantial crack means a crack in which a crack (crack) has progressed by 50% or more with respect to the length of the sample piece width.

[Evaluation of scratch resistance]
The scratch resistance was evaluated by scraping the cured coating film with a coin and checking for scratches. The results are shown in Tables 7 and 8. A case where no scratch was found with a coin was indicated as “◎”, a case where a scratch was hardly seen with a coin was indicated as “◯”, and a slight scratch was found with a coin but was substantially within the allowable range. Was marked with “Δ”, and “x” was marked when the coin was scratched and substantially exceeded the allowable range.

[Evaluation of tack]
Evaluation of tack was performed at room temperature.
The laminate was placed at room temperature, and the coated film was touched with a finger to check for stickiness. The results are shown in Tables 7 and 8. The case where there was no stickiness was indicated as “◯”, the case where there was a slight stickiness but substantially within the allowable range was indicated as “Δ”, and the case where stickiness was strong and substantially exceeded the allowable range was indicated as “X”.

Monomer A): a monofunctional monomer having a cyclic structure, and monomer B): a trifunctional or higher functional monomer having “molecular weight / number of functional groups ≧ 200”. The cured film made from an active energy ray-curable ink having a total of 85.0 mol% or more and monomer B of 0.5 mol% or more and 10.0 mol% or less has stretchability, repeated stretchability, scratch resistance and tackiness. Since it is excellent in the balance of performance, it was confirmed that it is an excellent active energy ray-curable ink that can be used even for a substrate having elasticity like an elastomer resin.

In particular, the active energy ray-curable inks according to Example 1 and Examples 3 to 10 have a monomer B) content of 1.0 mol% or more and 7.0 mol% or less. It was confirmed that the ink was an active energy ray-curable ink having an excellent balance of repeated stretchability, scratch resistance and tack performance.

Furthermore, in the active energy ray-curable inks according to Example 2 and Examples 7, 8, and 10, among the bifunctional monomers, the monomer C) of “molecular weight / functional group ≧ 200” is 1.3 mol% or more. Since it was contained in an amount of less than 0 mol%, it was confirmed that the ink was an active energy ray-curable ink having scratch resistance and excellent extensibility. In addition, the evaluation criteria in Examples 7 and 8 and Table 7 in Example 10 indicate that the extensibility evaluation is “◎”. However, the monomer C) is also superior to Example 10 having excellent extensibility. It was confirmed that Examples 7 and 8 containing 1.5 mol% or more and less than 2.6 mol% are active energy ray-curable ink compositions that form a cured film having further excellent stretchability.

In addition, since the laminated body which concerns on an Example is the evaluation of "(circle)" or "(double-circle)" in the extending | stretching test extended | stretched in 25 degreeC in the range of elongation rate from 0% to 100%, these laminated bodies are According to JIS K7161 method, even when a tensile test is performed at 25 ° C. and a tensile speed of 100 mm / min, it is estimated that the elongation at break of the cured film at which the cured film breaks is 50% or more.

On the other hand, in Comparative Example 1 in which the total of monofunctional monomers is not contained in an amount of 85.0 mol% or more, the ratio of polyfunctional monomers is higher than that in Examples, and the crosslink density is high. However, the stretchability was inferior, and it was confirmed that a cured film was formed that could not be said to have an excellent balance of stretchability, repeated stretchability, scratch resistance, and tack performance.

Moreover, although the sum total of the monofunctional monomer is contained 85.0 mol% or more, the comparative example 2 which does not contain the monomer B) 0.5 mol% or more has a low ratio of a polyfunctional monomer compared with an Example. Therefore, although the crosslink density is low and the stretchability is good, the cured film has poor scratch resistance and cannot be said to have excellent balance of stretchability, repeated stretchability, scratch resistance, and tack performance. It was confirmed that it was formed.

Furthermore, in Comparative Example 3 in which the total amount of monomers B) exceeds 10.0 mol%, the ratio of the polyfunctional monomer is higher than that in Examples, so that the crosslinking density is high, and the scratch resistance is Although it was good, the stretchability was inferior, and it was confirmed that a cured film that could not be said to have an excellent balance of stretchability, repeated stretchability, scratch resistance, and tack performance was formed.

Furthermore, Comparative Example 4 which does not contain the monomer B) and includes a polyfunctional monomer having a Mw / functional group number of less than 200 has a high crosslinking density due to a short crosslinking point distance. Although the properties were good, the stretchability was inferior, and it was confirmed that a cured film that could not be said to have an excellent balance of stretchability, repeated stretchability, scratch resistance and tack performance was formed.

Therefore, in the extensibility evaluation in Comparative Examples 1, 3 and 4, large cracks were observed exceeding 3 and substantially exceeding the allowable range. Therefore, these laminates were at 25 ° C. according to JIS K7161 method. Even when a tensile test is performed at a tensile rate of 100 mm / min, it is presumed that the elongation at break of the cured film at which the cured film cracks is less than 50%.

Articles for which the active energy ray-curable ink composition of the present invention can be used include automobile members, household appliance members, electronic device members, battery members, information office equipment members, optical members, household goods, industrial members It can be widely used for building materials, flooring materials, packaging materials, etc. Specifically, it can be used for rubber and plastics, hoses, packaging films, packaging materials, tubes, synthetic leather, electronic device exterior materials, and the like.

Claims

As an active energy ray polymerizable monomer,
Monomer A): a monofunctional monomer having a cyclic structure;
Monomer B): a trifunctional or higher functional monomer having a molecular weight / number of functional groups ≧ 200,
In the total amount of the active energy ray polymerizable monomer,
The total content of all monofunctional monomers including the monomer A) is 85.0 mol% or more,
An active energy ray-curable ink composition having a content of the monomer B) of 0.5 mol% or more and 10.0 mol% or less.
2. The active energy ray-curable ink composition according to claim 1, wherein the content ratio of the monomer A) in the entire monofunctional monomer is 60.0 mol% or more and 100.0 mol% or less.
In the total amount of the active energy ray polymerizable monomer,
The active energy ray-curable ink composition according to claim 1 or 2, wherein the content of the monomer B) is 1.0 mol% or more and 7.0 mol% or less.
As the active energy ray polymerizable monomer,
4. The active energy ray-curable ink composition according to claim 1, comprising a monomer C: a bifunctional monomer having a molecular weight / number of functional groups ≧ 200. 5.
The active energy ray-curable ink composition according to claim 4, wherein the content of the monomer C) in the total amount of the active energy ray polymerizable monomer is 0.5 mol% or more and 5.0 mol% or less.
The active energy ray-curable ink composition according to claim 1, which is used as an inkjet ink.
A laminate in which an ink cured film layer that is a cured film of the active energy ray-curable ink composition according to any one of claims 1 to 6 is formed on a substrate.
The laminate according to claim 7, wherein the base material is rubber.
The active energy ray-curable ink composition is formed as a cured film having a thickness of 10 μm on a nitrile rubber (hereinafter referred to as “NBR”) sheet having a thickness of 1 mm, and the cured film-forming base on which the cured film is formed. When a material is subjected to a tensile test at 25 ° C. and a tensile speed of 100 mm / min as a dumbbell-shaped No. 6 (JIS K6251-5) test piece, the cured film breakage point at which the cured film breaks. The active energy ray-curable ink composition according to claim 1, wherein the elongation is 50% or more.
The active energy ray-curable ink composition is formed on a 1 mm thick NBR sheet as a cured film having a thickness of 10 μm, and the elongation percentage of the cured film-forming substrate on which the cured film is formed ranges from 0% to 30%. When the expansion and contraction of the cured film forming substrate is repeated 10 times at a strain rate of 100 mm / min so as to repeat the range, the number of cracks in the cured film is 3 or less. The active energy ray-curable ink composition as described.
An image forming method for forming an image, a concavo-convex image, or an image and a concavo-convex image on a substrate using the active energy ray-curable ink composition according to any one of claims 1 to 6, 9, or 10.