Inkjet ink composition

Abstract

To provide an inkjet ink composition which secures adhesiveness to various base materials or a coated film and can be cured with high curability.SOLUTION: There is provided an inkjet ink composition which comprises s silane compound and / or a polymerizable compound having a hydroxyl group, a polymerizable compound having a heterocyclic skeleton and a photopolymerization initiator, wherein when the amount (mass%) of a monofunctional polymerizable compound contained in ink composition is defined as A and the amount (mass%) of a polyfunctional polymerizable compound contained in the ink composition is defined as B, 0.03≤B / A≤0.30 and 50 mass%≤A+B≤95 mass%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an inkjet ink composition, and more particularly to an inkjet ink composition that ensures adhesion to various substrates and coatings and is highly curable. [Background technology]

[0002] Inkjet inks are used to decorate substrates such as paper and building boards. In particular, active energy ray-curable inks, which have short curing times and excellent productivity, have been attracting attention in recent years, and their use in a variety of fields, including plastic and glass substrates, ceramics, and metal decoration, has been investigated and put to practical use.

[0003] International Publication No. 2012 / 133667 (Patent Document 1) describes a method for producing a multilayer coating film by forming an undercoat coating layer, an active energy ray-curable ink layer, and a topcoat coating layer on a substrate, in which the surface free energy of the undercoat coating layer, the surface tension of the active energy ray-curable ink, and the surface free energy of the topcoat paint are set within specific ranges to obtain a decorative laminate for building interior and exterior use that has a highly decorative pattern on the surface and has excellent adhesion, water resistance, and weather resistance. Patent Document 1 also describes that a preferred form of the active energy ray-curable ink is one that contains 50 to 90% by mass of a monomer having an ethylenically unsaturated group.

[0004] Japanese Patent Application Laid-Open No. 2016-65200 (Patent Document 2) describes an invention relating to an actinic ray-curable inkjet ink composition capable of forming printed matter with excellent adhesion to substrates, and describes that the adhesion of the printed layer to the substrate can be improved by using a specific (meth)acrylic acid ester compound having a hydroxyl group as a radical polymerizable monomer.

[0005] JP 2020-55901 A (Patent Document 3) describes an invention aimed at providing an actinic ray-curable inkjet ink composition that has excellent adhesion, particularly to substrates such as glass substrates, and is capable of forming a printed layer that has sufficient hardness and is scratch-resistant. Specifically, the invention describes an actinic ray-curable inkjet ink composition that contains an alicyclic monofunctional (meth)acrylate having a specific glass transition temperature, a hydroxyl group-containing monofunctional (meth)acrylate having a specific glass transition temperature, and a trifunctional or higher polyfunctional (meth)acrylate having a specific (meth)acrylic equivalent, wherein the amount of the polyfunctional (meth)acrylate is within a specific range.

[0006] Japanese Patent Application Laid-Open No. 2019-217680 (Patent Document 4) describes an invention relating to a printed matter comprising an ink layer made of an active energy ray-curable ink and a surface protective layer laminated on a substrate, and describes that by setting the monomer emission rate of the ink layer and the monomer emission rate of the surface protective layer within a certain range, it is possible to provide a printed matter with little emission of unreacted monomer. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2012 / 133667 [Patent Document 2] JP 2016-65200 A [Patent Document 3] Japanese Patent Publication No. 2020-55901 [Patent Document 4] Japanese Patent Application Publication No. 2019-217680 Summary of the Invention [Problem to be solved by the invention]

[0008] Regarding the polymerizable compounds used in actinic energy ray-curable ink compositions, blending a monofunctional polymerizable compound makes it easier to obtain a printed film that has excellent substrate adhesion and cured film flexibility, but a monofunctional polymerizable compound alone cannot form a crosslinked structure, resulting in weak film strength and poor curability. In contrast, a multifunctional polymerizable compound easily forms a printed film with high film strength by forming a crosslinked structure, and has superior curability compared to a monofunctional compound due to the large number of reaction sites. However, a multifunctional polymerizable compound alone has problems with adhesion due to the influence of cure shrinkage. Therefore, the ratio of the monofunctional polymerizable compound to the multifunctional polymerizable compound is important in order to obtain good film properties.

[0009] However, simply adjusting the ratio of the monofunctional polymerizable compound to the polyfunctional polymerizable compound is insufficient when considering adhesion to various substrates, adhesion to undercoat coating films and topcoat coating films, and curability of the ink.

[0010] Therefore, an object of the present invention is to provide an ink-jet ink composition that can be cured with high curability while ensuring adhesion to various substrates and coating films. [Means for solving the problem]

[0011] As a result of intensive research to achieve the above object, the present inventors have found that adhesion to various substrates and coating films can be ensured by specifying the amounts of monofunctional polymerizable compounds and polyfunctional polymerizable compounds contained in the ink composition at a specific ratio and by using a silane compound and / or a polymerizable compound having a hydroxyl group. Furthermore, they have also found that the curability of the ink can be improved by using a polymerizable compound having a heterocyclic skeleton as the polymerizable compound contained in the ink composition.

[0012] Therefore, a first aspect of the present invention is a polymerizable composition comprising a silane compound and / or a polymerizable compound having a hydroxyl group, a polymerizable compound having a heterocyclic skeleton, and a photopolymerization initiator, The inkjet ink composition is characterized in that, when the amount (% by mass) of the monofunctional polymerizable compound contained in the ink composition is A and the amount (% by mass) of the polyfunctional polymerizable compound contained in the ink composition is B, 0.03≦B / A≦0.30 and 50% by mass≦A+B≦95% by mass.

[0013] In a preferred embodiment of the ink-jet ink composition of the present invention, the average number of functional groups of the polymerizable compound contained in the ink composition is 1.2 or less.

[0014] In another preferable embodiment of the ink-jet ink composition of the present invention, the polymerizable compound having a heterocyclic skeleton is a nitrogen-containing polymerizable compound.

[0015] In another preferred embodiment of the ink-jet ink composition of the present invention, the polymerizable compound contained in the ink composition contains 1 to 20 mass % of a bifunctional polymerizable compound having a molecular weight of 300 to 1500 and 55 to 80 mass % of a monofunctional polymerizable compound.

[0016] In another preferred embodiment of the ink-jet ink composition of the present invention, the weighted average PII value of the polymerizable compounds contained in the ink composition is less than 2.00. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide an inkjet ink composition that ensures adhesion to various substrates and coatings and is highly curable. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention will be described in detail below.

[0019] One aspect of the present invention is an inkjet ink composition containing a polymerizable compound and a photopolymerization initiator. In this specification, this inkjet ink composition is also referred to as the "ink composition of the present invention." The inkjet ink refers to an ink used in an inkjet printing method.

[0020] The inkjet ink composition of the present invention contains a polymerizable compound and is an ink composition that can be cured by irradiation with actinic energy rays such as ultraviolet rays, visible light, and electron beams, and is therefore suitable as an actinic energy ray-curable ink composition.

[0021] The polymerizable compound is a compound that undergoes a polymerization reaction via a radically polymerizable functional group (e.g., a photopolymerizable unsaturated group such as a carbon-carbon double bond constituting an acryloyl group, a methacryloyl group, a vinyl group, or an allyl group). A radically polymerizable carbon-carbon double bond is also called an "ethylenically unsaturated double bond." The polymerizable compound may be used alone or in combination of two or more types.

[0022] Polymerizable compounds are classified into monofunctional polymerizable compounds and polyfunctional polymerizable compounds. Here, examples of monofunctional polymerizable compounds include monofunctional polymerizable monomers having one functional group exhibiting radical polymerizability (for example, monofunctional polymerizable monomers having one polymerizable unsaturated group) and monofunctional polymerizable oligomers having one functional group exhibiting radical polymerizability (for example, monofunctional polymerizable oligomers having one polymerizable unsaturated group). Examples of polyfunctional polymerizable compounds include polyfunctional polymerizable monomers having two or more functional groups exhibiting radical polymerizability (for example, polyfunctional polymerizable monomers having two or more polymerizable unsaturated groups) and polyfunctional polymerizable oligomers having two or more functional groups exhibiting radical polymerizability (for example, polyfunctional polymerizable oligomers having two or more polymerizable unsaturated groups).

[0023] In the ink composition of the present invention, where A is the amount (mass%) of the monofunctional polymerizable compound contained in the ink composition and B is the amount (mass%) of the polyfunctional polymerizable compound contained in the ink composition, the ratios of 0.03≦B / A≦0.30 and 50% by mass≦A+B≦95% by mass are satisfied. The inventors have discovered that in an ink composition containing 50 to 95% by mass of polymerizable compounds, by setting the ratio of polyfunctional polymerizable compound to monofunctional polymerizable compound to 0.30 or less, cure shrinkage of the film can be suppressed and adhesion of the film itself can be improved. This ensures adhesion to various substrates and coatings. Furthermore, by setting the amounts of monofunctional polymerizable compound and polyfunctional polymerizable compound contained in the ink composition to the specified ratio, curability and film strength can be ensured. Here, B / A is preferably 0.10 to 0.30. Furthermore, A+B is preferably 60 to 95% by mass.

[0024] The polymerizable compound contained in the ink composition of the present invention preferably has an average functionality of 1.2 or less, more preferably 1.05 to 1.2. The present inventors investigated the optimal number of reactive sites and crosslinking density to reduce the number of reactive sites in the entire system to suppress cure shrinkage while providing a moderate crosslinked structure to ensure film strength. As a result, they found that when the average functionality of the polymerizable compound contained in the ink composition is 1.2 or less, particularly 1.05 to 1.2, it is highly effective in suppressing cure shrinkage of the film, significantly improving the adhesion of the film itself, and maintaining film strength. This makes it possible to ensure adhesion to various substrates and coatings and film strength.

[0025] In this specification, the average number of functional groups of the polymerizable compound contained in the ink composition can be calculated as follows. Average number of functional groups = [total number of ethylenically unsaturated double bonds contained in polymerizable compounds] / [total number of molecules of polymerizable compounds] Formula (1) Here, the "total number of ethylenically unsaturated double bonds contained in the polymerizable compound" in formula (1) is calculated by multiplying the number of ethylenically unsaturated double bonds per molecule of the polymerizable compound by the total number of molecules of the polymerizable compound. When multiple types of polymerizable compounds are blended in the ink, the number of ethylenically unsaturated double bonds is calculated for each type, and the total number of ethylenically unsaturated double bonds is the sum of all the ethylenically unsaturated double bonds. (Example of how to determine the average number of functional groups of a polymerizable compound) The total amount of the polymerizable compounds is 100 parts by mass. Polymerizable compound A: number of ethylenically unsaturated double bonds = 1, molecular weight X A , 30 parts by mass Polymerizable compound B: number of ethylenically unsaturated double bonds = 2, molecular weight X B , 70 parts by mass Average number of functional groups={(1×30 / X A )+(2×70 / X B )} / {(30 / X A )+(70 / X B )}

[0026] To achieve an average functionality of 1.05 to 1.2, it is useful to use a polyfunctional polymerizable compound with a large ethylenically unsaturated double bond equivalent. The ethylenically unsaturated double bond equivalent is the value obtained by dividing the molecular weight by the number of ethylenically unsaturated double bonds contained in one molecule. When the ethylenically unsaturated double bond is derived from a (meth)acryloyl group, it is also called the "acrylic equivalent." Generally, the larger this value, the greater the distance between crosslinking points and the lower the crosslinking density, which ultimately contributes to reducing cure shrinkage.

[0027] The polymerizable compound contained in the ink composition of the present invention preferably contains 55 to 80% by mass of a monofunctional polymerizable compound. When the amount of the monofunctional polymerizable compound relative to the total polymerizable compounds is 55% by mass or more, adhesion and flexibility can be improved. Furthermore, if the proportion of the monofunctional polymerizable compound is too high, film strength and curability decrease, so the proportion of the monofunctional polymerizable compound relative to the total polymerizable compounds is preferably 80% by mass or less. More preferably, the amount of the monofunctional polymerizable compound relative to the total polymerizable compounds is 55 to 75% by mass.

[0028] The polymerizable compound contained in the ink composition of the present invention preferably contains 1 to 20% by mass, particularly 3 to 20% by mass, of a bifunctional polymerizable compound having a molecular weight of 300 to 1500. From the viewpoint of achieving both adhesion and curability, it is preferable to use a polymerizable compound having two functional groups exhibiting radical polymerization (bifunctional polymerizable compound). Furthermore, from the viewpoint of suppressing cure shrinkage, it is preferable to use a polymerizable compound having a relatively high molecular weight, and the molecular weight of the bifunctional polymerizable compound is preferably 300 to 1500, more preferably 300 to 1300. It is more preferable that the amount of the bifunctional polymerizable compound having a molecular weight of 300 to 1500 relative to the total polymerizable compounds is 5 to 20% by mass.

[0029] In the present specification, when the polymerizable compound is an oligomer, the molecular weight thereof can be measured as a weight average molecular weight converted into polystyrene by gel permeation chromatography.

[0030] Examples of the bifunctional polymerizable compound include a bifunctional polymerizable monomer and a bifunctional polymerizable oligomer. In the ink composition of the present invention, the amount of the bifunctional polymerizable compound is preferably 3 to 20% by mass, and more preferably 5 to 20% by mass.

[0031] The ink composition of the present invention preferably contains a polymerizable compound having a heterocyclic skeleton. By using a polymerizable compound having a heterocyclic skeleton, it is possible to improve the curability. Furthermore, the polymerizable compound having a heterocyclic skeleton is preferably a nitrogen-containing polymerizable compound, and more preferably a polymerizable compound in which the heterocyclic skeleton contains a nitrogen atom. In particular, a nitrogen-containing polymerizable compound as a polymerizable compound having a heterocyclic skeleton is highly effective in reducing polymerization inhibition due to oxygen during curing, and can improve the curability of the ink. In the ink composition of the present invention, the amount of the polymerizable compound having a heterocyclic skeleton is preferably 1 to 10% by mass.

[0032] The ink composition of the present invention preferably contains a polymerizable compound having a hydroxyl group. By using a polymerizable compound having a hydroxyl group, adhesion to the substrate and film strength can be improved by hydrogen bonding or chemical bonding via the hydroxyl group. Furthermore, similar to polymerizable compounds having a heterocyclic skeleton, it has the effect of reducing oxygen inhibition during curing, and improved curability can be expected. In one embodiment of the present invention, the ink composition contains at least one of a polymerizable compound having a hydroxyl group and a silane compound described below, and preferably contains both a polymerizable compound having a hydroxyl group and a silane compound. In the ink composition of the present invention, the amount of the polymerizable compound having a hydroxyl group is preferably 1 to 10% by mass.

[0033] The ink composition of the present invention preferably contains a polymerizable compound having a silicon atom, and more preferably contains a polymerizable compound represented by the following formula (1). By using a polymerizable compound having a silicon atom as a silane compound, it is possible to improve adhesion to a substrate. In particular, the polymerizable compound represented by formula (1) is excellent in the effect of improving adhesion. In the ink composition of the present invention, the amount of the polymerizable compound having a silicon atom is preferably 1 to 5 mass %. [ka] [In formula (1), n ​​is 1 to 3, Y is a methoxy group or an ethoxy group, R is an alkylene group selected from C3, and Z is a (meth)acryloxy group.]

[0034] The polymerizable compound contained in the ink composition of the present invention preferably has a weighted average PII value of less than 2.00. PII is an abbreviation for Primary Irritation Index, which can also be translated as primary skin irritation index. The higher the primary skin irritation (PII), the more likely it is that the ink will cause chemical irritation to the skin, with symptoms such as rashes becoming more likely. This can lead to dangerous and difficult-to-handle conditions for both the work environment and the workers involved. Furthermore, problems can arise when monomers with high primary skin irritation remain in the coating film even after the curing process. Therefore, it is desirable to design safe inks with as low a PII as possible. The Society of Industrial Technology for Antibacterial Products (SIAA) cites the absence of any irritation or a low level of irritation (PII (primary irritation index): less than 2.00) as the standard for safety. The weighted average of the PII values ​​of the polymerizable compounds contained in the ink composition is determined as follows. Polymerizable compound A:PII=P A , mass ratio=T A Polymerizable compound B:PII=P B , mass ratio=T B Weighted average of PII = P A ×T A +P B ×T B ...Calculation formula (2)

[0035] Specific examples of monofunctional polymerizable monomers include isoamyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, 2-ethylhexyl-diglycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, ethyl carbitol (meth)acrylate, 2-(2'-vinyl Oxyethoxy)ethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 4-t-butylcyclohexyl (meth)acrylate, cyclohexyl (meth)acrylate, N-(meth)acryloylmorpholine, tetrahydrofurfuryl (meth)acrylate, (2-methyl-2-ethyl-1,3-Dioxolan-4-yl)methyl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, γ-butyrolactone (meth)acrylate, N-vinylcaprolactam, N-(meth)acryloyloxyethylhexahydrophthalimide, 1-(meth)acryloylpyrrolidin-2-one, 1-(meth)acryloylpiperidin-2-one, N-vinyl-2-pyrrolidone, N-vinylimidazole, dimethylacrylamide, hydroxyethyl (meth)acrylamide , diethyl acrylamide, isopropyl acrylamide, dimethylaminopropyl (meth)acrylamide, diacetone acrylamide, Nn-butoxymethyl acrylamide, N-isobutoxymethyl acrylamide, N-methoxymethyl acrylamide, N-methylolacrylamide, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, benzyl (meth)acrylate, neopentyl glycol (meth)acrylic acid benzoate, iso Bornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropyltriethoxysilane, γ-(meth)acryloxypropylmethyldimethoxysilane, γ-(meth)acryloxypropylmethyldiethoxysilane, γ-(meth)acryloxypropylmethyldipropoxysilane, γ-(meth) Examples of suitable monomers include acryloxybutylphenyldimethoxysilane, γ-(meth)acryloxypropyldimethylmethoxysilane, γ-(meth)acryloxypropyldiethylmethoxysilane, β-(meth)acryloxyethyltrimethoxysilane, β-(meth)acryloxyethyltriethoxysilane, polyoxyethylene mono(meth)acrylate, polyoxypropylene mono(meth)acrylate, polyoxybutylene mono(meth)acrylate, and those modified with alkylene glycol. Among these, monofunctional polymerizable monomers with an elongated alkyl chain or alkylene glycol chain are preferred because their increased molecular weight reduces odor compared to before chain elongation.

[0036] Among the polyfunctional polymerizable monomers, specific examples of polyfunctional polymerizable monomers (bifunctional polymerizable monomers) having two functional groups exhibiting radical polymerization include 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,7-heptanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-octanediol di(meth)acrylate, 1,10-octanediol di(meth)acrylate, 1,11-octanediol di(meth)acrylate, 1,12-octanediol di(meth)acrylate, 1,13-octanediol di(meth)acrylate, 1,14-octanediol di(meth)acrylate, 1,15-octanediol di(meth)acrylate, 1,16-octanediol di(meth)acrylate, 1,17-octanediol di(meth)acrylate, 1,18-octanediol di(meth)acrylate, 1,19-octanediol di(meth)acrylate, 1,20-octanediol di(meth)acrylate, 1,21-octanediol di(meth)acrylate, 1,22-octanediol di(meth)acrylate, 1,23-octanediol di(meth)acrylate, 1,24-octanediol di(meth)acrylate, 1,25-octanediol di(meth)acrylate, 1,26-octanediol di(meth)acrylate, 1,27-octanediol di(meth)acrylate, 1,28-octanediol di(meth)acrylate, 1,29-octanediol di(meth)acrylate, 1,30-octanediol di(meth Diol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, PO (propylene oxide)-modified neopentyl glycol di(meth)acrylate, cyclohexanedimethanol diacrylate, tricyclodecane dimethanol diacrylate, dimethylol-tricyclodecane di(meth)acrylate, dicyclopentanyl diacrylate, bisphenol A di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, and the like.

[0037] Specific examples of polyfunctional polymerizable monomers having three or more functional groups exhibiting radical polymerization (tri- or higher functional polyfunctional polymerizable monomers) include trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, ethoxylated glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, EO-modified diglycerin tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, EO-modified dipentaerythritol hexa(meth)acrylate, and glycerin tri(meth)acrylate.

[0038] As used herein, the term "(meth)acrylate" refers to either methacrylate or acrylate. For example, 2-hydroxyethyl (meth)acrylate is 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate. When a prefix indicating plural is added to a (meth)acrylate, such as di(meth)acrylate or tri(meth)acrylate, each (meth)acrylate may be the same or different.

[0039] The polymerizable oligomer is preferably an acrylic oligomer, which is an oligomer having an acryloyl group or a methacryloyl group as a radically polymerizable functional group.

[0040] The polymerizable oligomer is preferably a polyfunctional polymerizable oligomer, more preferably a polyfunctional acrylic oligomer. The number of functional groups of the polymerizable oligomer is preferably 2 to 6, and the molecular weight of the polymerizable oligomer is preferably 800 to 20,000. The molecular weight of the polymerizable oligomer is a weight average molecular weight in terms of polystyrene.

[0041] Specific examples of acrylic oligomers include polyurethane acrylic oligomers [acrylic oligomers with multiple urethane bonds (-NHCOO-)], polyester acrylic oligomers [acrylic oligomers with multiple ester bonds (-COO-)], polyamino acrylic oligomers [acrylic oligomers with multiple amino groups (-NH2)], polyepoxy acrylic oligomers [acrylic oligomers with multiple epoxy groups], silicone acrylic oligomers [acrylic oligomers with multiple siloxane bonds (-SiO-)], and polybutadiene acrylic oligomers [acrylic oligomers with multiple butadiene units].

[0042] Further, the following acrylic oligomers are known: Beam Set 502H, Beam Set 505A-6, Beam Set 550B, Beam Set 575, Beam Set AQ-17 (manufactured by Arakawa Chemical Industries, Ltd.), AH-600, UA-306H, UA-306T, UA-306I, UA-510H, UF-8001G (manufactured by Kyoeisha Chemical Co., Ltd.), CN910, CN959, CN963, CN964, CN965NS, CN966NS, CN969NS, CN980NS, CN981NS, CN982, CN983NS, CN985, CN991NS, CN996NS, CN 2920, CN2921, CN8881NS, CN8883NS, CN9001NS, CN9004, CN9005, CN9009, CN9011, CN9021NS, CN9023, CN9028, CN9030, CN917 8NS, CN9290, CN9893NS, CN929, CN989NS, CN968NS, CN9006NS, CN9010NS, CN9025, CN9026, CN9039, CN9062, CN9110NS, CN9029, CN8885NS, CN9013NS, CN973, CN978NS, CN992, CN9167, CN9782, CN9783, CN970, CN971, CN972, CN975NS, CN9165 (manufactured by Sartomer Corporation), U-2PPA, U-6LPA, U-10HA, U-10PA, UA-1100H, U-15HA, UA-53H, UA-33H, U-200PA, UA-200PA, UA-160TM, UA-290TM, UA-4200, UA-4400, UA-122P (manufactured by Shin-Nakamura Chemical Co., Ltd.), New Frontier R-1235, R-1220, RST-201, RST-402, R-1301, R-1304, R-1214, R-1302XT, GX-8801A, R-1603, R-1150D (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), EBECRYL204, EBECRYL205, EBECRYL210, EBECRYL215, EBECRYL220, EBECRYL230, EBECRYL244, EBECRYL245, EBECRYL264, EBECRYL265, EBECRYL270, EBECRY L280 / 15IB, EBECRYL284, EBECRYL285, EBECRYL294 / 25HD, EBECRYL1259, EBECRYL1290, KRM8200, EBECRYL4820, EBECRYL4858, EBECRYL5129, EBECRYL7100, EBECRYL8210, EBECRYL8254, EBECRYL8301R, EBECRYL8307, EBECRYL8402, EBECRYL8405, EBECRYL8411, EBECRYL8465, EBECRYL8800, EBECRYL8804, EBECRYL8807, EBECRYL9260, EBECRYL9270, EBECRYL7735, EBECRYL8296, EBECRYL8452, EBECRYL8904, EBECRYL8311, EBECRYL8701, EBECRYL8667 (manufactured by Daicel-Allnex Co., Ltd.), UV-1700B, UV-6300B, UV-7550B, UV-7600B, UV-7605B, UV-7610B, UV-7630B, UV-7640B, UV-7650B, UV-6630B, UV-7000B, UV-7510B, UV-7461TE, UV-2000B, UV-2750B, UV-3000B, UV-3200B, UV-3300B, UV-3310B, UV-3700B, UV6640B (manufactured by Nippon Gosei Kagaku Co., Ltd.), Art resin UN-333, UN-350, UN-1255, UN-2600, UN-2700, UN-5590, UN-6060PTM, UN-6200, UN-6202, UN-6300, UN-6301, UN-7600, UN-7700, UN-9000PEP, UN-9200A, UN-3320HA, UN-3320HC, UN-904, UN-906S (manufactured by Neagari Kogyo), Aronix M-6100, M-6250, M-6500, M-7100, M-7300K, M-8030, M-8060, M-8100, M-8530, M-8560, M-9050 (manufactured by Toagosei Co., Ltd.)

[0043] Specific examples of polymerizable compounds having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, polyoxyethylene mono(meth)acrylate, polyoxypropylene mono(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and caprolactone-modified hydroxyethyl acrylate. Other polymerizable compounds having a hydroxyl group include polymerizable compounds that generate hydroxyl groups by thermal decomposition, such as N-methylolacrylamide. Furthermore, polymerizable compounds having a hydroxyl group may be synthesized or commercially available products may be used.

[0044] Specific examples of polymerizable compounds having silicon atoms include γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropyltriethoxysilane, β-(meth)acryloxyethyltrimethoxysilane, β-(meth)acryloxyethyltriethoxysilane, γ-(meth)acryloxypropylmethyldimethoxysilane, γ-(meth)acryloxypropylmethyldiethoxysilane, γ-(meth)acryloxypropylmethyldipropoxysilane, γ-(meth)acryloxybutylphenyldimethoxysilane, γ-(meth)acryloxypropyldimethylmethoxysilane, γ-(meth)acryloxypropyldiethylmethoxysilane, etc. Among these, examples of polymerizable compounds represented by formula (1) include γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyldimethylmethoxysilane, etc.

[0045] Specific examples of polymerizable compounds having a heterocyclic skeleton include N-acryloylmorpholine, N-methacryloylmorpholine, γ-butyrolactone (meth)acrylate, N-vinylcaprolactam, N-acryloyloxyethylhexahydrophthalimide, N-methacryloyloxyethylhexahydrophthalimide, 1-acryloylpyrrolidin-2-one, 1-methacryloylpyrrolidin-2-one, 1-acryloylpiperidin-2-one, 1-methacryloylpiperidin-2-one, N-vinyl-2-pyrrolidone, N-vinylimidazole, tetrahydrofurfuryl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, and cyclic trimethylolpropane formal (meth)acrylate. Among these, N-acryloylmorpholine is particularly preferred because it contains nitrogen.

[0046] The photopolymerization initiator has the effect of initiating polymerization of the polymerizable compound described above when irradiated with active energy rays. The amount of the photopolymerization initiator in the ink composition is preferably 1 to 15% by mass, more preferably 1 to 12% by mass, and even more preferably 1 to 10% by mass. If the content of the polymerization initiator is less than 1% by mass, the film may not cure properly, and if it exceeds 15% by mass, precipitates may form at low temperatures, making the ink ejection unstable. Furthermore, to promote the initiation reaction of the polymerization initiator, an auxiliary agent such as a photosensitizer may also be used in combination.

[0047] Examples of photopolymerization initiators include benzophenone-based compounds, acetophenone-based compounds, thioxanthone-based compounds, and acylphosphine oxide-based compounds. From the viewpoint of curability, however, it is preferable that the wavelength of the irradiated active energy ray overlaps as much as possible with the absorption wavelength of the photopolymerization initiator. In particular, from the viewpoint of coloration during curing and curability in thick films, it is preferable that the photopolymerization initiator contains an acylphosphine oxide-based initiator. The photopolymerization initiator may be used alone or in combination of two or more.

[0048] It is preferable to use two or more photopolymerization initiators with different wavelength ranges. This improves the polymerizability of the compound. Furthermore, by combining one with two cleavage points with one with one cleavage point, the initiation radical concentration increases, further improving the polymerizability and degree of cure.

[0049] As the acylphosphine oxide initiator, it is preferable to use a monoacylphosphine oxide initiator and a bisacylphosphine oxide initiator in combination. Here, it is particularly preferable that the mass ratio (C:D) of the monoacylphosphine oxide initiator (C) to the bisacylphosphine oxide initiator (D) is 1:1 to 5:1.

[0050] Specific examples of the photopolymerization initiator include: 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]-phenyl}-2-methyl-propan-1-one, Phenylglyoxylic acid methyl ester, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], Ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime), 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, etc.

[0051] Among these, from the viewpoint of ink curing properties, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, and 2 Furthermore, from the viewpoints of coloration during curing and curability in the case of thick films, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide are preferred, with 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide being particularly preferred.

[0052] The ink composition of the present invention preferably contains a silane coupling agent, and more preferably contains a silane coupling agent represented by the following formula (2). By using a silane coupling agent as the silane compound, adhesion to the substrate can be improved. Furthermore, the silane compound represented by formula (2) also has excellent pigment dispersibility, and can improve the storage stability of the ink. In the ink composition of the present invention, the amount of the silane coupling agent is preferably 1 to 10 mass %. The silane coupling agents may be used alone or in combination of two or more. [ka] [In formula (2), n is 1 to 3, Y is a methoxy group or an ethoxy group, R is an alkylene group selected from C3, and X is a glycidoxy group or an epoxycyclohexyl group.] The epoxycyclohexyl group is a cyclohexyl group in which an epoxy group is formed by two carbon atoms and an oxygen atom that constitute the cyclohexyl ring, and is a group having a condensed ring structure of an epoxy ring and a cyclohexyl ring.

[0053] Specific examples of silane coupling agents include glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, β-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyldimethylmethoxysilane, and γ-glycidoxypropylmethyldimethoxysilane. Epoxy group-containing silane coupling agents such as propyl(ethyl)dimethoxysilane, β-3,4-epoxycyclohexylethyltrimethoxysilane, β-3,4-epoxycyclohexylethyltriethoxysilane, 8-glycidoxyoctyltrimethoxysilane, 8-glycidoxyoctylmethyldimethoxysilane, and 8-glycidoxyoctylmethyldiethoxysilane; γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-aminopropyltriisopropoxysilane; Silane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldiethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriisopropoxysilane, N-phenyl-γ-amino Examples of the silane coupling agents include amino group-containing silane coupling agents such as propyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, γ-anilinopropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-vinylbenzyl-γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-8-aminooctyltrimethoxysilane, and γ-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine.

[0054] Among these, examples of the silane coupling agent represented by formula (2) include γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and γ-glycidoxypropyldimethylmethoxysilane.

[0055] The ink composition of the present invention preferably contains a silane compound. Use of a silane compound can improve adhesion to a substrate and dispersibility of a pigment. In one embodiment of the present invention, the ink composition contains at least one of a silane compound and the above-mentioned polymerizable compound having a hydroxyl group, and preferably contains both a silane compound and a polymerizable compound having a hydroxyl group. In the ink composition of the present invention, the amount of the silane compound is preferably 0.5 to 10% by mass. The silane compounds may be used alone or in combination of two or more.

[0056] Examples of the silane compound include a polymerizable compound having a silicon atom, preferably a polymerizable compound represented by formula (1), and a silane coupling agent, preferably a silane coupling agent represented by formula (2).

[0057] The ink composition of the present invention preferably contains, as a silane compound, at least one of a polymerizable compound represented by formula (1) and a silane coupling agent represented by formula (2), and more preferably contains both a polymerizable compound represented by formula (1) and a silane coupling agent represented by formula (2). When a polymerizable compound represented by formula (1) and a silane coupling agent represented by formula (2) are used in combination, the mass ratio (E:F) of the polymerizable compound (E) represented by formula (1) to the silane coupling agent (F) represented by formula (2) is particularly preferably 1:2 to 2:1.

[0058] The ink composition of the present invention may contain a coloring material such as a dye or a pigment. In this case, it is preferable to contain a pigment, particularly an inorganic pigment, from the viewpoint of weather resistance. The content of the coloring material in the ink composition is, for example, 1 to 20% by mass. The coloring material may be used alone or in combination of two or more types.

[0059] Specific examples of coloring materials include: CIPigment Yellow 1, 2, 3, 4, 5, 6, 7, 9, 10, 12, 13, 14, 15, 16, 17, 24, 32, 34, 35, 36, 37, 41, 42, 43, 49, 53, 55, 60, 61, 62, 63, 65, 73, 74, 75, 77, 81, 83, 87, 93, 94, 95, 97, 98, 99, 100, 101, 104, 105, 106, 108, 109, 110, 111, 113, 114, 116, 117, 119, 120, 123, 124, 126, 127, 128, 129, 130, 133, 138, 139, 150, 151, 152, 153, 154, 155, 165, 167, 168, 169, 170, 172, 173, 174, 175, 176, 179, 180, 181, 182, 183, 184, 185, 191, 193, 194, 199, 205, 206, 209, 212, 213, 214, 215, 219, CIPigment Orange 1, 2, 3, 4, 5, 13, 15, 16, 17, 19, 20, 21, 24, 31, 34, 36, 38, 40, 43, 46, 48, 49, 51, 60, 61, 62, 64, 65, 66, 67, 68, 69, 71, 72, 73, 74, 81, C.I.Pigment Red 1、2、3、4、5、6、7、8、9、10、11、12、14、15、16、17、18、21、22、23、31、32、38、41、48、48:1、48:2、48:3、48:4、48:5、49、52、52:1、52:2、53:1、54、57:1、58、60:1、63、64:1、68、81:1、83、88、89、95、101、104、105、108、112、114、119、122、123、136、144、146、147、149、150、164、166、168、169、170、171、172、175、176、177、178、179、180、181、182、183、184、185、187、188、190、193、194、200、202、206、207、208、209、210、211、213、214、216、220、220、221、224、226、237、238、239、242、245、247、248、251、253、254、255、256、257、258、260、262、263、264、266、268、269、270、271、272、279、 C.I.Pigment Violet 1、2、3、3:1、3:3、5:1、13、15、16、17、19、23、25、27、29、31、32、36、37、38、42、50、 C.I.Pigment Blue 1、15、15:1、15:2、15:3、15:4、15:5、15:6、16、17:1、24、24:1、25、26、27、28、29、36、56、60、61、62、63、75、79、80、 C.I.Pigment Green 1、4、7、8、10、15、17、26、36、50、 C.I.Pigment Brown 5、6、23、24、25、32、41、42、 C.I.Pigment Black 1、6、7、9、10、11、20、26、28、31、32、34、 C.I.Pigment White 1、2、4、5、6、7、11、12、18、19、21、22、23、26、27、28、 Examples include aluminum flakes, glass flakes, pearl pigments, and hollow particles.

[0060] Among these, from the viewpoint of weather resistance and color reproducibility of the obtained film, CIPigment Black 7, CIPigment Blue 15:3, CIPigment Blue 15:4, CIPigment Blue 28, CIPigment Red 101, CIPigment Red 122, CIPigment Red 202, CIPigment Red 254, CIPigment Red 282, CIPigment Violet 19, CIPigment White 6, CIPigment Yellow 42, CIPigment Yellow 120, CIPigment Yellow 138, CIPigment Yellow 139, CIPigment Yellow 150, CIPigment Yellow 151, CIPigment Yellow 155, CIPigment Yellow 184, and CIPigment Yellow 213 are preferred.

[0061] The ink composition of the present invention may further contain a pigment dispersant as needed to disperse the pigment. The content of the pigment dispersant in the ink composition is, for example, 0.1 to 5% by mass. The pigment dispersants may be used alone or in combination of two or more.

[0062] Specific examples of pigment dispersants include: ANTI-TERRA-U, ANTI-TERRA-U100, ANTI-TERRA-204, ANTI-TERRA-205, DISPERBYK-101, DISPERBYK-102, DISPERBYK-103, DISPERBYK-106, DISPERBYK-108, DISPERBYK-109, DISPERBYK-110, DISPERBYK-111, DISPERBYK-112, DISPERBYK-116, DISPERBYK-130, DISPERBYK-140, DISPERBYK-142, DISPERBYK-145, DISPERBYK-161, DISPERBYK-162, DISPERBYK-163, DISPERBYK-164, DISPERBYK-166, DISPERBYK-167, DISPERBYK-168, DISPERBYK-170, DISPERBYK-171, DISPERBYK-174, DISPERBYK-180, DISPERBYK-182, DISPERBYK-183, DISPERBYK-184, DISPERBYK-185, DISPERBYK-2000, DISPERBYK-2001, DISPERBYK-2008, DISPERBYK-2009, DISPERBYK-2020, DISPERBYK-2025, DISPERBYK-2050, DISPERBYK-2070, DISPERBYK-2096, DISPERBYK-2013, DISPERBYK-2150, DISPERBYK-2155, DISPERBYK-2163, DISPERBYK-2164, BYK-P104, BYK-P104S, BYK-P105, BYK-9076, BYK-9077, BYK-220S, BYKJET-9150, BYKJET-9151 (all manufactured by BYK Japan), Solsperse3000, Solsperse5000, Solsperse9000, Solsperse11200, Solsperse13240, Solsperse13650, Solsperse13940, Solsperse16000, Solsperse17000, Solsperse18000, Solsperse20000, Solsperse21000, Solsperse24000SC, Solsperse24000GR, Solsperse26000, Solsperse27000, Solsperse28000, Solsperse32000, Solsperse32500, Solsperse32550, Solsperse32600, Solsperse33000, Solsperse34750, Solsperse35100, Solsperse35200, Solsperse36000, Solsperse36600, Solsperse37500, Solsperse38500, Solsperse39000, Solsperse41000, Solsperse54000, Solsperse55000, Solsperse56000, Solsperse71000, Solsperse76500, SolsperseJ180, SolsperseJ200, SolsperseX300 (all manufactured by Lubrizol), Disparlon DA-7301, Disparlon DA-325, Disparlon DA-375, Disparlon DA-234 (all manufactured by Kusumoto Chemicals Co., Ltd.), FLORENE AF-1000, FLORENE DOPA-15B, FLORENE DOPA-15BHFS, FLORENE DOPA-17HF, FLORENE DOPA-22, FLORENE DOPA-33, FLORENE G-600, FLORENE G-700, FLORENE G-700AMP, FLORENE G-700DMEA, FLORENE G-820, FLORENE G-900, FLORENE GW-1500, FLORENE KDG-2400, FLORENE NC-500, FLORENE WK-13E (all manufactured by Kyoeisha Chemical Co., Ltd.), TEGO Dispers610, TEGO Dispers610S, TEGO Dispers630, TEGO Dispers650, TEGO Dispers652, TEGO Dispers655, TEGO Dispers662C, TEGO Dispers670, TEGO Dispers685, TEGO Dispers700, TEGO Dispers710, TEGO Dispers740W, LIPOTIN A, LIPOTIN BL, LIPOTIN DB, LIPOTIN SB (both manufactured by Evonik Degussa), PB821, PB822, PN411, PA111 (all manufactured by Ajinomoto Fine-Techno Co., Ltd.), Texahall 963, Texahall 964, Texahall 987, Texahall P60, Texahall P61, Texahall P63, Texahall 3250, Texahall SF71, Texahall UV20, Texahall UV21 (all manufactured by Cognis), Examples include BorchiGenSN88 and BorchiGen0451 (both manufactured by Borchias).

[0063] The ink composition of the present invention may further contain a surface conditioner from the viewpoint of improving wettability, etc. In this specification, a surface conditioner means a substance that has a hydrophilic moiety and a hydrophobic moiety in its molecular structure and that can adjust the surface tension of the ink composition by adding it.

[0064] Specific examples of surface conditioners that can be used in the ink composition of the present invention include anionic surface conditioners such as dialkyl sulfosuccinates, alkyl naphthalene sulfonates, and fatty acid salts; nonionic surface conditioners such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, and polyoxyethylene-polyoxypropylene block copolymers; cationic surface conditioners such as alkylamine salts and quaternary ammonium salts; acrylic surface conditioners, silicone surface conditioners, and fluorine-based surface conditioners. Silicon-based and acrylic surface conditioners are particularly preferred, and commercially available products from BYK, Evonik, Dow Corning Toray, and other companies can be used. Furthermore, in the case of silicone-based surface conditioners, polyether-modified silicone oils with an HLB value of 7.6 to 12 are preferred.

[0065] The amount of the surface conditioner can be appropriately selected depending on the purpose of use, but is preferably 0.01 to 1 mass % in the ink composition. The surface conditioner may be used alone or in combination of two or more types.

[0066] Specific examples of surface conditioners include: BYK-300, BYK-302, BYK-306, BYK-307, BYK-310, BYK-313, BYK-315N, BYK-320, BYK-322, BYK-323, BYK-325, BYK-326, BYK-330, BYK-331, BYK-333, BYK-342, BYK-345, BYK-346, BYK-347, BYK-348, BYK-349, BYK-350, BYK-354, BYK-355, BYK-356, BYK-358N, BYK-361N, BYK-370, BYK-375, BYK-377, BYK-378, BYK-381, BYK-392, BYK-394, BYK-399, BYK-3440, BYK-3441, BYK-3455, BYK-3550, BYK-3560, BYK-3565, BYK-3760, BYK-DYNWET 800N, BYK-SILCLEAN 3700, BYK-SILCLEAN 3701, BYK-SILCLEAN 3720, BYK-UV3500, BYK-UV3505, BYK-UV3510, BYK-UV3530, BYK-UV3535, BYK-UV3570, BYK-UV3575, BYK-UV3576 (above, manufactured by BYK Chemie Japan Co., Ltd.), TEGO Flow 300, TEGO Flow 370, TEGO Flow 425, TEGO Flow ATF 2, TEGO Flow ZFS 460, TEGO Glide 100, TEGO Glide 110, TEGO Glide 130, TEGO Glide 406, TEGO Glide 410, TEGO Glide 411, TEGO Glide 415, TEGO Glide 432, TEGO Glide 435, TEGO Glide 440, TEGO Glide 450, TEGO Glide 482, TEGO GlideA 115, TEGO GlideB 1484, TEGO GlideZG 400 (above, manufactured by Evonik Japan Co., Ltd.), 501W ADDITIVE, FZ-2104, FZ-2110, FZ-2123, FZ-2164, FZ-2191, FZ-2203, FZ-2215, FZ-2222, FZ-5609, L-7001, L-7002, L-7604, OFX-0193, OFX-0309 FLUID, OFX-5211 FLUID, SF 8410 FLUID, SH3771, SH 3746 FLUID, SH 8400 FLUID, SH 8700 FLUID, Y-7006 (all manufactured by Dow Corning Toray Co., Ltd.), Examples of such polysiloxanes include KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-640, KF-642, KF-643, KF-644, KF-945, KF-6004, KF-6011, KF-6012, KF-6015, KF-6017, KF-6020, KF-6204, X-22-2516, and X-22-4515 (all manufactured by Shin-Etsu Chemical Co., Ltd.).

[0067] The ink composition of the present invention may contain an ultraviolet absorber. The ultraviolet absorber has the effect of absorbing ultraviolet rays and preventing deterioration caused by ultraviolet rays. Examples of the ultraviolet absorber include cyanoacrylate-based compounds, benzophenone-based compounds, benzoate-based compounds, benzotriazole-based compounds, hydroxyphenyltriazine-based compounds, benzylidene camphor-based compounds, and inorganic fine particles.

[0068] Specific examples of ultraviolet absorbers include: 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone-2-hydroxy-4-benzyloxybenzophenone, bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole 2-[2'-hydroxy-3',5'-bis(α,α-(dimethylbenzyl)phenyl]benzotriazole, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-t-amylphenyl)benzotriazole, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, 2,2'-methylene-bis[4-(1,1,3,3-tetramethylbutyl)-6-(2N-benzotriazol-2-yl)phenol], Condensation products of methyl-3-[3-t-butyl-5-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]propionate and polyethylene glycol, 2-(2-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2,6-di-t-butylphenyl-3',5'-di-t-butyl-4'-hydroxybenzoate, hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate and the like.

[0069] In the ink composition of the present invention, the amount of ultraviolet absorber is preferably within the range of 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, and even more preferably 1 to 5% by mass. If the amount of ultraviolet absorber is too large, the film may not be sufficiently cured. The ultraviolet absorber may be used alone or in combination of two or more types, but it is preferable that the ultraviolet absorber contains at least two types of ultraviolet absorbers. By using multiple types of ultraviolet absorbers with different structures, the effect of the ultraviolet absorbers can be maintained longer.

[0070] The ink composition of the present invention may contain a radical scavenger. The radical scavenger can scavenge free radicals and improve light stability. Substances that react with free radicals and have the function of preventing polymerization reactions (so-called polymerization inhibitors) are also included in radical scavengers.

[0071] Examples of the radical scavenger include hindered amine compounds, hydroquinone compounds, phenol compounds, phenothiazine compounds, nitroso compounds, and N-oxyl compounds, with hindered amine light stabilizers (HALS) being particularly preferred.

[0072] Specific examples of the radical scavenger include hindered amine compounds such as bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, 1-{2-(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy)ethyl}-2,2,6,6-tetramethylpiperidine, and 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro{4.5}decane-2,4-dione; phenol; o-, m-, or p-cresol; phenolic compounds such as 2-t-butyl-4-methylphenol, 6-t-butyl-2,4-dimethylphenol, 2,6-di-t-butyl-4-methylphenol, 2-t-butylphenol, 4-t-butylphenol, 2,4-di-t-butylphenol, 2-methyl-4-t-butylphenol, 4-t-butyl-2,6-dimethylphenol, hydroquinone, hydroquinone monomethyl ether, methylhydroquinone, 2,5-di-t-butyl hydroquinone compounds such as benzoquinone, 2-methyl-p-hydroquinone, 2,3-dimethylhydroquinone, trimethylhydroquinone, 4-methylbenzcatechin, t-butylhydroquinone, 3-methylbenzcatechin, 2-methyl-p-hydroquinone, 2,3-dimethylhydroquinone, trimethylhydroquinone, t-butylhydroquinone, benzoquinone, t-butyl-p-benzoquinone, 2,5-diphenyl-p-benzoquinone, and phenothiazine compounds; nitroso-based compounds such as N-nitroso-N-phenylhydroxylamine ammonium and N-nitroso-N-phenylhydroxylamine aluminum salt; and N-oxyl-based compounds such as 4-hydroxy-2,2,6,6-tetramethyl-piperidine-N-oxyl, 4-oxo-2,2,6,6-tetramethyl-piperidine-N-oxyl, and 4-methoxy-2,2,6,6-tetramethyl-piperidine-N-oxyl.

[0073] In the ink composition of the present invention, the amount of radical scavenger is preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less. If the amount of radical scavenger is too high, it may cause poor curing. The lower limit of the content of radical scavenger is, for example, 0.01% by mass or more, preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more. The radical scavengers may be used alone or in combination of two or more.

[0074] The ink composition of the present invention may contain a resin. The resin has the role of forming a film on the substrate while capturing solid components such as pigments, and contributes to improving the adhesion of the ink composition to the substrate.

[0075] Specific examples of resins include polyvinyl acetate, vinyl chloride-vinyl acetate copolymers, vinyl chloride resins, chlorinated rubber, chlorinated polyethylene resins, chlorinated polypropylene resins, chlorinated ethylene-vinyl acetate resins, acrylic resins, polystyrene resins, polyamide resins, polyurethane resins, polyolefin resins, silicone resins, fluororesins, epoxy resins, polyester resins, ketone resins, phenolic resins, polyvinyl alcohol, polyvinyl alcohol derivatives (anion-modified polyvinyl alcohol, etc.), cellulose, cellulose derivatives (hydroxymethyl cellulose, hydroxyethyl cellulose, cellulose acetate, etc.), rosin resins, alkyd resins, alginic acid, alginic acid derivatives (propylene glycol alginate, etc.), and the like. Modified versions of these resins are also included. For example, for resins having hydroxyl groups, modifications such as hydroxyalkyl ether modifications and carboxylic acid modifications can be mentioned.

[0076] In the ink composition of the present invention, the amount of resin is preferably 25% by mass or less, particularly 10% by mass or less, and more preferably 8% by mass or less. If the amount of resin is too large, it may cause poor curing. The lower limit of the resin content is, for example, 1% by mass or more, preferably 3% by mass or more. The resin may be used alone or in combination of two or more types.

[0077] The ink composition of the present invention may contain, as other components, additives such as antioxidants, plasticizers, rust inhibitors, solvents, antibacterial agents, antiviral agents, viscosity adjusters, fillers, antifoaming agents, charge control agents, stress relaxation agents, penetrating agents, light-guiding materials, luster materials, magnetic materials, and fluorescent materials, as needed.

[0078] The ink composition of the present invention can be prepared by mixing various components appropriately selected as needed. In addition, it is preferable to filter the ink composition using a filter in order to prevent clogging of the nozzles of the head due to impurities, etc.

[0079] The ink composition of the present invention preferably has a viscosity at 40°C of 5 to 25 mPa·s, more preferably 5 to 20 mPa·s. When the ink viscosity at 40°C is within the above-specified range, good ejection stability can be obtained. The ink viscosity can be measured using a cone-plate viscometer. The temperature at which the ink is ejected is preferably 30°C to 50°C.

[0080] The ink composition of the present invention preferably has a surface tension of 20 to 35 mN / m, more preferably 23 to 33 mN / m, at 25°C. When the ink surface tension at 25°C is within the above-specified range, good ejection stability can be obtained. The ink surface tension can be measured by a plate method.

[0081] Printing with the ink composition of the present invention is carried out by an inkjet printing method. Various inkjet printers can be used for inkjet printing. Examples of inkjet printers include inkjet printers that eject the ink composition using a charge control method or a piezoelectric method. Large-format inkjet printers, specifically inkjet printers designed for printing on products produced on industrial lines, can also be suitably used.

[0082] The layer formed by printing using the ink composition of the present invention is cured by irradiation with active energy rays such as ultraviolet rays. Examples of light sources for active energy rays include high-pressure mercury lamps, metal halide lamps, and LED lamps. The wavelength of the active energy rays irradiated to cure this layer preferably overlaps with the absorption wavelength of the photopolymerization initiator, and the dominant wavelength of the active energy rays is preferably 350 to 400 nm. The cumulative light intensity of the active energy rays is 100 to 2000 mJ / cm. 2 It is preferable that the temperature is in the range of

[0083] The ink composition of the present invention can be used to achieve a surface finish such as a glossy finish, a matte finish, etc. by appropriately selecting the ejection conditions for inkjet printing and the subsequent curing conditions. For example, if the ink composition spreads and then hardens over time, it will have a glossy finish, and if the ink droplets harden while remaining in a lens shape, it will have a matte finish.

[0084] The substrate on which printing is performed using the ink composition of the present invention is not particularly limited, and examples thereof include paper, coated paper, plastic materials, and building boards. The substrate may be in the form of a film, sheet, or plate. Examples of the substrate material include plastics such as epoxy resin, ABS resin, polycarbonate, polyvinyl chloride, polystyrene, and acrylic resin, particularly polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), and polypropylene (PP); metals such as iron, stainless steel, aluminum, copper, titanium, and alloys thereof; wood, cement, concrete, gypsum, calcium silicate, calcium carbonate, marble, artificial marble, glass, and ceramics. Combinations of two or more of these materials may also be used. The surface of the substrate may be subjected to pretreatments such as degreasing, chemical conversion coating, and polishing, or may be coated with a sealer or primer. The substrate surface may be smooth, uneven, or three-dimensional. Specific examples of substrates include plastic materials such as PVC sheets, tarpaulin, plastic cardboard, and acrylic sheets; papers such as coated paper (specifically, resin-coated paper), art paper, cast paper, lightly coated paper, fine paper, synthetic paper, and inkjet paper; wooden building materials made from wood such as veneer, plywood, particle board, and medium-density fiberboard (MDF); inorganic building materials such as ceramic siding boards, flexible boards, calcium silicate boards, gypsum slag barite boards, wood chip cement boards, pulp cement boards, precast concrete boards, lightweight aerated concrete (ALC) boards, and gypsum boards; metal building materials such as aluminum, iron, and stainless steel, tiles, and glass plates.

[0085] The substrate may have a layer (e.g., a coating film or a printed film) formed on a part or the entire surface thereof. For example, a coating film formed from paint, a printed film formed from ink, a printed film formed from powder toner, or the like may be formed on the substrate. The layer formed on the substrate may contain resin, coloring material such as dye or pigment, ultraviolet absorber, radical scavenger, antioxidant, plasticizer, rust inhibitor, filler, charge control agent, light guiding material, luster material, magnetic material, phosphor, wax, or the like.

[0086] Examples of paints and inks used to form a layer on a substrate include organic solvent-based paints and inks that use an organic solvent as the main solvent, water-based paints and inks that use water as the main solvent, photocurable paints and inks that use a polymerizable compound, powder paints, and various other paints and inks. Here, examples of components that can be used in the case of photocurable inks include the components that can be used in the ink composition of the present invention described above.

[0087] The means for forming a layer on a substrate is not particularly limited. For example, in the case of paint, various coating means such as air spray, airless spray, roll coater, flow coater, and electrostatic coating can be used. In addition, in the case of ink, various printing means such as gravure printing, offset printing, flexographic printing, screen printing, coater printing, and inkjet printing can be used. In the case of powder toner, electrophotographic development printing means (specifically, image forming devices such as copiers and laser printers) can usually be used.

[0088] Another layer (e.g., a coating film or a printed film) may be formed on a layer formed by printing using the ink composition of the present invention. For example, a coating film formed from a paint, a printed film formed from an ink, etc. may be formed. Another layer that can be disposed on a layer formed from the ink composition of the present invention may contain a resin, a coloring material such as a dye or a pigment, an ultraviolet absorber, a radical scavenger, an antioxidant, a plasticizer, a rust inhibitor, an algae inhibitor, an antifungal agent, an antibacterial agent, an antiviral agent, a filler, a charge control agent, a light-guiding material, a lustrous material, a magnetic material, a phosphor, wax, etc.

[0089] Examples of paints and inks that can be used to form another layer on a layer formed from the ink composition of the present invention include organic solvent-based paints and inks that use an organic solvent as the main solvent, water-based paints and inks that use water as the main solvent, photocurable paints and inks that use a polymerizable compound, powder paints, and various other paints and inks. Here, examples of components that can be used in the case of photocurable inks include the components that can be used in the ink composition of the present invention described above.

[0090] The means for forming another layer on a layer formed from the ink composition of the present invention is not particularly limited. For example, in the case of a paint, various coating means such as air spray, airless spray, roll coater, flow coater, and electrostatic coating can be used. In addition, in the case of an ink, various printing means such as gravure printing, offset printing, flexographic printing, screen printing, coater printing, and inkjet printing can be used. [Example]

[0091] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples in any way.

[0092] Mixtures according to the formulations shown in Tables 1 to 7 were obtained, kneaded in a bead mill to homogenize them, and filtered using a filter to prepare inkjet inks. The evaluation results of the obtained inkjet ink are shown in Table 8.

[0093] [Table 1]

[0094] [Table 2]

[0095] [Table 3]

[0096] [Table 4]

[0097] [Table 5]

[0098] [Table 6]

[0099] [Table 7]

[0100] [Table 8]

[0101] The notes in the table are as follows: a) Caprolactone-modified hydroxyethyl acrylate Plaxel FA2D (Manufactured by Daicel Allnex) b) Aminoacrylate EBECRYL 7100 (manufactured by Daicel Allnex Co., Ltd.) c) Aliphatic urethane acrylate EBECRYL 8402 (Manufactured by Daicel Allnex) d) Pigment dispersant BYKJET-9151 (manufactured by BYK Japan) Furthermore, the item "Number of ethylenically unsaturated double bonds (A) = 1, (B) ≧ 2 (B) / (A)" in the table shows the B / A value when the amount (% by mass) of the monofunctional polymerizable compound contained in the ink composition is A and the amount (% by mass) of the polyfunctional polymerizable compound contained in the ink composition is B. The item "PII value of ink composition" in the table shows the weighted average of the PII values ​​of the polymerizable compounds contained in the ink composition.

[0102] The evaluation methods and evaluation criteria for curability, adhesion, and pencil hardness are described below. An ink composition that shows favorable evaluation results in terms of curability, adhesion, and pencil hardness can be said to be practical.

[0103] <Curability> The ink composition was applied to an acrylic resin substrate using a bar coater #5, and then cured by irradiation with active energy rays. The ink curability was evaluated. A metal halide lamp was used as the light source, and active energy rays with a dominant wavelength of 360 to 425 nm were irradiated at 100 mJ / cm. 2 The ink cured film was then irradiated with light, and then wiped dry with a cloth. The presence of color transfer to the cloth was visually confirmed, and the above irradiation and dry wiping were repeated until no color transfer occurred. The ink composition was deemed to have been cured completely when no color transfer occurred, and curability was evaluated based on the integrated light intensity required until completion. The evaluation criteria were as follows. The results are shown in Table 8. In practice, an evaluation result of △ or better is preferable, ○ or better is more preferable, and ⊚ can be said to be an ink composition with very high curability. ◎: 100mJ / cm 2 No color transfer. ○: 200mJ / cm 2 No color transfer. △: 300~1000mJ / cm 2 No color transfer. ×:1000mJ / cm 2 Even if irradiated for more than this, color transfer will occur (the resin will not harden completely).

[0104] <Adhesion> Cured ink films were prepared using the same method as in the curing test described above, and adhesion was evaluated. In addition to acrylic resin substrates, polycarbonate, ABS resin, and polyvinyl chloride substrates were also used. The adhesion test was conducted according to JIS K-5600-1-6 and evaluated according to the following criteria. The results are shown in Table 8. The evaluation criteria were classified such that a lower number indicated a higher grade, with a grade of 2 or higher being sufficient for practical use, 1 being more preferable, and 0 indicating an ink composition with high adhesion. 0: The edges of the cut are completely smooth and there are no flaking marks on any of the grids. 1: Small peeling of the coating at the intersection of the cuts. The affected area of ​​the cross-cuts does not significantly exceed 5%. 2: The coating is peeling along the edges of cuts and / or at intersections. The cross-cut area is clearly more than 5% affected but not more than 15%. 3: The coating has partially or completely peeled off significantly along the edges of the cuts and / or partially or completely peeled off in various areas of the mesh. The cross-cut area is clearly more than 15% affected but not more than 35%. 4: The coating is partially or completely torn off in large areas along the edges of the cuts and / or partially or completely torn off in several sections. Not more than 65% of the cross-cut area is affected. 5: Any degree of peeling that cannot be classified as category 4.

[0105] <Pencil hardness> The ink cured films obtained in the above test for curability were evaluated for pencil hardness using the scratch hardness (pencil method) in accordance with JIS K-5600-5-4. The results are shown in Table 8. A pencil hardness of F or higher is preferred, and an ink composition with a pencil hardness of H or higher can be said to have high film strength.

Claims

1. the composition includes a silane compound, a radical polymerizable compound having a heterocyclic skeleton, and a photopolymerization initiator, and may further include a radical polymerizable compound having a hydroxyl group; the silane compound contains a radical polymerizable compound having a silicon atom and / or a silane coupling agent, 1. An inkjet ink composition, wherein, when the amount (% by mass) of a monofunctional radical polymerizable compound contained in the ink composition is A and the amount (% by mass) of a polyfunctional radical polymerizable compound contained in the ink composition is B, 0.10≦B / A≦0.30 and 50% by mass≦A+B≦95% by mass.

2. the composition includes a silane compound, a radical polymerizable compound having a heterocyclic skeleton, and a photopolymerization initiator, and may further include a radical polymerizable compound having a hydroxyl group; The silane compound is represented by the following formula (1): 【Chemical 1】 [In formula (1), n ​​is 1 to 3, Y is a methoxy group or an ethoxy group, R is an alkylene group selected from C3, and Z is a (meth)acryloxy group.] and a radical polymerizable compound represented by the following formula (2): 【Chemistry 2】 [In formula (2), n is 1 to 3, Y is a methoxy group or an ethoxy group, R is an alkylene group selected from C3, and X is a glycidoxy group or an epoxycyclohexyl group.] and at least one of the silane coupling agents represented by 1. An inkjet ink composition, characterized in that, when the amount (% by mass) of a monofunctional radical polymerizable compound contained in the ink composition is A and the amount (% by mass) of a polyfunctional radical polymerizable compound contained in the ink composition is B, 0.03≦B / A≦0.30 and 50% by mass≦A+B≦95% by mass.

3. 3. The ink-jet ink composition according to claim 1, wherein the average number of functional groups of the radically polymerizable compound contained in the ink composition is 1.2 or less.

4. 4. The ink-jet ink composition according to claim 1, wherein the radically polymerizable compound having a heterocyclic skeleton is a nitrogen-containing radically polymerizable compound.

5. 5. The inkjet ink composition according to claim 1, wherein the radical polymerizable compound contained in the ink composition contains 1 to 20% by mass of a bifunctional radical polymerizable compound having a molecular weight of 300 to 1,500 and 55 to 80% by mass of a monofunctional radical polymerizable compound.

6. 6. The ink-jet ink composition according to claim 1, wherein the weighted average P.I.I. value of the radical polymerizable compound contained in the ink composition is less than 2.00.

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