JP7161286B2 - Dispersions for Ink Compositions, Ink Compositions, Laminates, Imaging Methods, and Methods of Making Prints - Google Patents

Description

TECHNICAL FIELD The present invention relates to a dispersion liquid, an ink composition, a laminate, an image forming method, and a method for producing a printed matter, for an ink composition that is cured by an active energy ray, which is mainly used as an inkjet ink.

Conventionally, active energy ray-curable ink compositions that are cured by active energy rays such as ultraviolet rays have been developed. Since the active energy ray-curable ink composition dries quickly, ink bleeding can be prevented even when printing on substrates that do not or hardly absorb ink, such as plastics, glass, and coated paper. The active energy ray-curable ink composition comprises an active energy ray-polymerizable monomer, a coloring material, other additives, and the like.

For example, Patent Document 1 discloses an ink composition comprising a pigment dispersant, an active energy ray-curable monomer, a quinophthalone-based pigment, and a quinophthalone-based pigment derivative. According to Patent Document 1, the ink composition described in Patent Document 1 is an ink composition excellent in ejection stability and storage stability.

Japanese Patent Application Laid-Open No. 2006-34205

A yellow pigment is a pigment that develops a yellow color by absorbing light of a relatively short wavelength such as blue or violet with a wavelength of about 400 nm to 480 nm. The inventors of the present invention have found that the curability of a yellow ink composition containing a yellow pigment is lowered depending on the combination of the yellow pigment and the pigment dispersant.

Moreover, since it is used as a yellow ink composition containing a yellow pigment, the cured film is required to have a predetermined hue from the viewpoint of image reproducibility. However, the present inventors have found that some combinations of a yellow pigment and a pigment dispersant change the hue and cannot be used as a yellow ink composition.

The ink composition described in Patent Literature 1 is described to improve ejection stability and storage stability. However, neither the relationship between the combination of the yellow pigment and the pigment dispersant and the curability of the ink composition nor the hue of the cured film formed by the ink composition is disclosed nor suggested.

The present invention has been made in view of the above circumstances, and provides an ink composition having excellent curability even when it is a dispersion liquid for an ink composition containing a yellow pigment, and a yellow ink composition. An object of the present invention is to provide a dispersion that can be used to produce an ink composition that forms a cured film having a hue suitable for the color.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by a dispersion in which the product of absorbance at wavelengths from 360 nm to 400 nm and the hue of the cured film are adjusted. , have completed the present invention. Specifically, the present invention provides the following.

以下の硬化膜作成条件で作成した硬化膜のＪＩＳ－Ｚ８７２２：２００９に基づいて、Ｄ５０光源、２°視野角の条件によって測定されたｂ^＊値が６５以上である分散液。
（硬化膜作成条件：分散液と、光重合開始剤と、を含有させたインク組成物を波長３６０ｎｍから４００ｎｍまでの光を含む光線を照射することにより硬化する。） (1) A dispersion for an ink composition that contains a yellow pigment and a pigment dispersant and is cured by an active energy ray, and is defined by the following formula in absorbance measurement: The absorbance product is 40 or less,

A dispersion having a b ^* value of 65 or more as measured under the conditions of a D50 light source and a viewing angle of 2° based on JIS-Z8722:2009 for a cured film prepared under the following cured film preparation conditions.
(Curing conditions for forming a cured film: The ink composition containing the dispersion liquid and the photopolymerization initiator is cured by irradiating it with a light beam containing light having a wavelength of 360 nm to 400 nm.)

(2) The dispersion according to (1), which is for an ink composition that is cured by light rays containing light having a wavelength of 360 nm to 400 nm.

(3) The dispersion according to (1) or (2), which further contains a pigment derivative.

(4) The dispersion liquid according to (3), wherein the pigment derivative is a pigment derivative containing a quinophthalone pigment derivative.

(5) The pigment dispersant has an amine value of 20 mgKOH/g or less and an acid value of 10 mgKOH/g or less, and includes repeating units derived from styrene and repeating units derived from unsaturated fatty acids having 12 or more carbon atoms. A copolymer having a unit and a repeating unit derived from a polyalkylene oxide having an ethylenically unsaturated double bond, an alkali metal salt of the copolymer, an alkaline earth metal salt of the copolymer, and the copolymer and an amine derivative of the copolymer.

（式（１）中、Ｒ^１は含酸素複素環構造を有する官能基である。Ｒ^２は炭素数１以上５以下のアルキレン基を示す。Ｒ^３は水素原子又はメチル基を示す。Ｒ^４は水素原子を示す。）
Ｒ^４－ＣＨ＝ＣＲ^１－ＣＯＯＲ^２－Ｏ－ＣＨ＝ＣＨ－Ｒ^３ ・・・（２）
（式（２）中、Ｒ^１は水素原子又はメチル基を示し、Ｒ^２は炭素数２以上２０以下の２価の有機残基を示し、Ｒ^３は水素原子又は炭素数１以上１１以下の１価の有機残基を示し、Ｒ^４は水素原子又は炭素数１以上４以下のアルキル基を示す。） (6) Furthermore, monomer A): a monofunctional monomer represented by the following general formula (1), and/or monomer B): a polyfunctional monomer represented by the following general formula (2), as active energy ray-polymerizable monomers and the dispersion according to any one of (1) to (5).

(In formula (1), R ¹ is a functional group having an oxygen-containing heterocyclic structure. R ² represents an alkylene group having 1 to 5 carbon atoms. R ³ represents a hydrogen atom or a methyl group. R ⁴ indicates a hydrogen atom.)
R ⁴ -CH=CR ¹ -COOR ² -O-CH=CH-R ³ (2)
(In formula (2), R ¹ represents a hydrogen atom or a methyl group, R ² represents a divalent organic residue having 2 to 20 carbon atoms, R ³ represents a hydrogen atom or a It represents a monovalent organic residue, and ^R4 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

(7) An ink composition containing the dispersion according to any one of (1) to (6).

(8) The ink composition according to (7), which further contains a photopolymerization initiator.

(9) The active energy ray-curable ink composition according to (7) or (8), which is cured by light containing light having a wavelength of 360 nm to 400 nm.

(10) The ink composition according to any one of (7) to (9), which is used as an inkjet ink.

(11) A laminate in which a cured ink film layer, which is a cured film of the ink composition according to any one of (7) to (10), is formed on a substrate.

(12) An image forming method for forming an image and/or an uneven image on a substrate using the ink composition according to any one of (7) to (10).

(13) The image forming method according to (12), wherein the image and/or the relief image are formed by irradiating the substrate with a light beam containing light having a wavelength of 360 nm to 400 nm.

(14) A method for producing a printed matter, comprising forming an image and/or an uneven image on a substrate using the ink composition according to any one of (7) to (10).

(15) The image forming method according to (14), wherein the image and/or the relief image are formed by irradiating the substrate with light containing light having a wavelength of 360 nm to 400 nm.

The dispersion liquid of the present invention is an ink composition having excellent curability even when it is a dispersion liquid for an ink composition containing a yellow pigment, and forms a cured film having a hue suitable as a yellow ink composition. It is a dispersion from which an ink composition can be prepared.

3 is a diagram showing the absorbance of the dispersions of Example 1 and Comparative Example 3. FIG.

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

<Dispersion>
The dispersion liquid of the present embodiment has a product of absorbance of 40 or less at wavelengths from 360 nm to 400 nm defined by the following formula in absorbance measurement.

Ink with excellent curability that effectively cures by irradiation with light rays containing light with a wavelength of 360 nm to 400 nm because the product of absorbance at wavelengths from 360 nm to 400 nm defined by the above formula is 40 or less. Compositions can be manufactured. The product of absorbances at wavelengths from 360 nm to 400 nm defined by the above formula is preferably 37 or less, more preferably 35 or less, and even more preferably 33 or less.

For the absorbance measurement, for example, UV-1800 manufactured by Shimadzu Corporation is used to irradiate light with a wavelength of 360 nm to 400 nm, and the absorbance is obtained from the incident light intensity _I0 and the transmitted light intensity I in the wavelength range of 360 nm to 400 nm. It can be obtained by obtaining A _λ (=log ₁₀ (I/I ₀ )) and integrating as in the above formula.

Specifically, when the measurement interval of the measurement wavelength is set to 0.5 nm, for example, (((absorbance A _λ of ink at wavelength X nm) + (absorbance of ink at wavelength (X + 0.5) nm A _λ )) × 0.5/2 means the area obtained by adding the area of a square (trapezoid) calculated from X in the range of 360 nm to 400 nm.In order to obtain a more accurate approximate area, measurement The wavelength intervals may be made small, for example, the absorbance may be measured at wavelengths from 360 nm to 400 nm at wavelength intervals of about 0.5 nm.

The dispersion liquid of the present embodiment is a dispersion liquid for an ink composition that can produce an ink composition having excellent curability in spite of containing a yellow pigment. Therefore, it is possible to produce a cured ink film layer having high scratch resistance and the like, and it is possible to produce an ink composition with high productivity because it cures quickly.

A yellow pigment is a pigment that exhibits a yellow color by absorbing light in the wavelength range of 400 nm to 500 nm, which is relatively short wavelength light such as violet or blue. Some yellow pigments may absorb not only visible light but also light with a shorter wavelength of 360 nm to 400 nm, which can be called ultraviolet light. Therefore, when the ink composition is cured by irradiating light containing light with a wavelength of 360 nm to 400 nm, the yellow pigment absorbs light with a wavelength of 360 nm to 400 nm. Therefore, it is considered that the polymerization reaction between the active energy initiator and the active energy ray-polymerizable monomer is inhibited, and the curability of the ink composition is lowered. The same applies to pigment derivatives obtained by derivatizing pigments.

Therefore, in the dispersion liquid of the present embodiment, the product of absorbance from wavelength 360 nm to 400 nm defined by the above formula is specified to be 40 or less. The absorbance product at wavelengths from 360 nm to 400 nm is 40 or less, thereby suppressing absorption of light necessary for polymerization of the active energy initiator and the active energy ray-polymerizable monomer by the yellow pigment. can be done.

Furthermore, the dispersion liquid of the present embodiment has a b ^* value of 65 or more measured under the conditions of a D50 light source and a 2° viewing angle based on JIS-Z8722:2009 for a cured film prepared under the following cured film preparation conditions. , preferably 66 or more. The cured film forming conditions are conditions under which the ink composition containing the dispersion liquid and the photopolymerization initiator is cured by irradiating it with a light beam containing light having a wavelength of 360 nm to 400 nm.

According to the opinion of the present inventors, it has been found that the combination of a yellow pigment and a pigment dispersant affects the conjugated system of the pigment and changes the absorption wavelength of the pigment. Therefore, even if the product of absorbance at wavelengths from 360 nm to 400 nm as defined above is 40 or less, the hue of the cured film may change and it may not be possible to use it as a yellow ink composition. be.

The dispersion liquid of the present embodiment is an ink composition having excellent curability by adjusting the product of absorbance at wavelengths from 360 nm to 400 nm in absorbance measurement and the hue of the cured film, and is suitable as a yellow ink composition. It is a dispersion capable of producing an ink composition that forms a cured film of a different hue.

An example of each component contained in the dispersion that satisfies the above requirements of the present embodiment will be described below.

[Yellow pigment]
A yellow pigment is a pigment classified as a yellow pigment in the color index (C.I). The pigment used as the yellow pigment is preferably a pigment that absorbs blue or purple light with a wavelength of about 400 nm to 480 nm, and preferably a pigment that does not absorb light with a wavelength of about 360 nm to 400 nm as much as possible.

For example, C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 20, 24, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 117, 120, 125, 128 , 129, 130, 137, 138, 139, 147, 148, 150, 151, 153, 154, 166, 168, 177, 180, 185, 213, 214 and the like.

Among them, it is preferable to use quinophthalone pigments. A quinophthalone pigment means a pigment synthesized from phthalic anhydride and quinaldine. Examples of quinophthalone-based pigments include Pigment Yellow 138 and Pigment Yellow 177.

Further, the dispersion of the present embodiment preferably further contains a pigment derivative containing a quinophthalone pigment derivative, and the quinophthalone pigment derivative is a quinophthalone derivative having a sulfonic acid group and/or a sulfonic acid group. It is more preferable to have The steric hindrance due to the structure of the quinophthalone-based pigment derivative can prevent the pigment from crystallizing and depositing, and can impart good dispersion stability to the quinophthalone pigment. The sulfonate group is a sulfonate group forming a salt represented by -(SO ₃ ^- ) _n X ⁿ⁺ , where X ⁿ⁺ is a monovalent or polyvalent metal ion, Primary, secondary, tertiary or quaternary ammonium cations are exemplified.

A quinophthalone derivative having a sulfonic acid group and/or a sulfonic acid group can be synthesized by reacting a quinophthalone pigment with concentrated sulfuric acid or the like. Specific examples include quinophthalonesulfonic acid and its amine salts, ammonium salts, and metal salts such as sodium and aluminum. In order to obtain a stable dispersion, a hydrophobic quinophthalone, which is easily soluble in the monomer that is the dispersion medium, is preferred, and a quinophthalone amine salt is particularly preferred. This is because the quinophthalone amine salt easily adsorbs to the quinophthalone pigment and is difficult to detach.

A pigment other than the quinophthalone-based pigment of the present embodiment or a pigment derivative other than the quinophthalone-based pigment derivative of the present embodiment may be contained as long as the effects of the present invention are not impaired.

The total content of the yellow pigment and the yellow pigment derivative is preferably 5% by mass or more, more preferably 7% by mass or more, and still more preferably 10% by mass or more in the total amount of the dispersion. The total content of the yellow pigment and the yellow pigment derivative is preferably 20% by mass or less, more preferably 17% by mass or less, and even more preferably 15% by mass or less in the total amount of the dispersion.

[Pigment Dispersant]
The pigment dispersant contained in the dispersion liquid of the present embodiment has an amine value of 20 mgKOH/g or less, an acid value of 10 mgKOH/g or less, a repeating unit derived from styrene, and a dispersant having 12 or more carbon atoms. A copolymer having a repeating unit derived from a saturated fatty acid and a repeating unit derived from a polyalkylene oxide having an ethylenically unsaturated double bond (hereinafter sometimes simply referred to as "copolymer"), a copolymer One or more selected from the group consisting of alkali metal salts, alkaline earth metal salts of copolymers, ammonium salts of copolymers, and amine derivatives of copolymers (hereinafter simply referred to as "copolymers, etc." There is.) is included. As long as the effect of the present invention is not impaired, other pigment dispersant may be included as necessary.

The amine value of the pigment dispersant is preferably 17 mgKOH/g or less from the viewpoint of excellent storage stability and liquid repellency to the ejection surface. Moreover, the acid value of the pigment dispersant is preferably 7 mgKOH/g or less from the viewpoint of excellent storage stability and liquid repellency to the ejection surface.

In the present specification, the amine value represents the mass (mg) of potassium hydroxide equivalent to the amount of hydrochloric acid required to neutralize 1 g of solid content, and is determined by the method described in JIS K7237: 1995. can be measured.

In addition, the acid value used herein represents the mass (mg) of KOH required to neutralize 1 g of solid content, and can be measured by the method described in JIS K0070:1992.

In addition, in this specification, solid content means the component except a solvent and a dispersion medium.

The above-mentioned specific copolymer used as a pigment dispersant in the present embodiment is a styrene-derived repeating unit, a repeating unit derived from an unsaturated fatty acid having 12 or more carbon atoms, and a poly having an ethylenically unsaturated double bond. It may have repeating units derived from alkylene oxide, and may further have other repeating units. The above-mentioned specific copolymer contains, as at least monomers, (1) styrene, (2) an unsaturated fatty acid having 12 or more carbon atoms, and (3) a polyalkylene oxide having an ethylenically unsaturated double bond. , copolymerized by the ethylenically unsaturated double bonds of the respective monomers. The repeating unit derived from each monomer means a structure in which the ethylenically unsaturated double bond of each monomer is open (a structure in which the double bond (C=C) becomes a single bond (-C-C-)). .

Hereinafter, the repeating units constituting the above copolymer will be described in order, but since the unit structure of (1) styrene is clear, the description will be omitted here.

(2) Unsaturated fatty acid having 12 or more carbon atoms The unsaturated fatty acid having 12 or more carbon atoms is not particularly limited as long as it has one or more ethylenic double bonds. Among them, from the viewpoint of dispersibility and dispersion stability of the pigment, unsaturated fatty acids having 12 or more carbon atoms are preferable, unsaturated fatty acids having 15 or more carbon atoms are preferable, and unsaturated fatty acids having 16 or more carbon atoms are preferable. Unsaturated fatty acids are more preferred. From the viewpoint of pigment dispersibility and dispersion stability, it is preferably an unsaturated fatty acid having 30 or less carbon atoms, preferably an unsaturated fatty acid having 20 or less carbon atoms, and an unsaturated fatty acid having 18 or less carbon atoms. Fatty acids are more preferred.

The position of the ethylenic double bond in the carbon chain of the unsaturated fatty acid is not particularly limited. From the viewpoint of dispersibility and dispersion stability of the pigment, it is preferable that the terminal carbon atom and the α-position (2-position) carbon atom of the carboxy group do not have an ethylenic double bond. For example, in the case of an unsaturated fatty acid having 16 or more and 18 or less carbon atoms, it is preferable to have a double bond at any adjacent carbon at positions 4 to 12.

Specific examples of unsaturated fatty acids having 12 or more carbon atoms include palmitoleic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linolenic acid, eleostearic acid, arachidonic acid, erucic acid, and nervonic acid. mentioned. Among them, palmitoleic acid, oleic acid, elaidic acid, and vaccenic acid are preferred.
The unsaturated fatty acids having 12 or more carbon atoms may be used singly or in combination of two or more.

The terminal carboxy group of the repeating unit derived from unsaturated fatty acid having 12 or more carbon atoms may be esterified and/or amidated.

The alcohol used for esterification is not particularly limited. Examples thereof include linear or branched alcohols having 1 to 30 carbon atoms, which may further have a substituent such as an aromatic group or an alicyclic group. Atoms may be included. Specific examples of alcohols used for esterification include 2-butoxyethanol, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, 2-phenoxyethanol, 2-(2-phenoxyethoxy) ethanol, and the like. be done. The above alcohols may be used singly or in combination of two or more.

Moreover, the compound used for amidation is not particularly limited. Examples thereof include ammonia, primary amines, secondary amines, aminoalcohols having 1 to 20 carbon atoms, and the like. Specific examples of compounds used for amidation include cyclohexylamine, octadecenylamine, dibutylamine, benzylamine, diisotridecylamine and the like.

The compounds used for the amidation may be used singly or in combination of two or more.

A polyalkylene oxide having an ethylenically unsaturated double bond can be obtained, for example, from allyl alcohol and an alkylene oxide having an oxirane ring by a known method.

(4) Other Repeating Units The above copolymer used as a pigment dispersant may further have other repeating units. Other repeating units include repeating units derived from a dicarboxylic acid compound having an ethylenically unsaturated bond. Specific examples thereof include maleic acid, fumaric acid, itaconic acid, citraconic acid and the like, and may be acid anhydrides such as maleic anhydride and citraconic anhydride.

In the repeating unit derived from the dicarboxylic acid compound, the carboxy group may be esterified, amidated, or imidized. The alcohol used for esterification and the compound used for amidation or imidization are not particularly limited. For example, the same compounds as those used for the esterification of unsaturated fatty acids having 12 or more carbon atoms can be used.

In addition, other repeating units include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and stearyl (meth)acrylate. Acrylates, Lauryl (meth)acrylate, Cyclohexyl (meth)acrylate, Benzyl (meth)acrylate, Trifluoromethyl (meth)acrylate, Hexafluoropropyl (meth)acrylate, Tetrafluoropropyl (meth)acrylate, Propylene glycol mono (meth)acrylate (Meth)acrylic acid esters such as acrylates and polyethylene glycol mono(meth)acrylate; α-methylstyrene, vinyltoluene, vinylcyclohexane; vinyl acetate, vinyl propionate, vinyl butanoate, vinyl hexanoate, vinyl octanoate, decanoic acid Vinyl esters of aliphatic or aromatic carboxylic acids such as vinyl, vinyl stearate, vinyl palmitate, vinyl propionate, divinyl adipate, divinyl sebacate, vinyl 2-ethylhexanoate, and vinyl trifluoroacetate; allyl propionate, allyl butanoate, allyl hexanoate, allyl octanoate, allyl decanoate, allyl stearate, allyl palmitate, allyl salicylate, allyl lactate, diallyl oxalate, allyl stearate, diallyl succinate, diallyl glutarate, Aliphatic or aromatic allyl esters such as diallyl adipate, diallyl pimelate, diallyl maleate, diallyl phthalate, and diallyl isophthalate; alkyl vinyl ethers such as vinyl ethyl ether and vinyl polyether. . In this specification, "(meth)acrylate" means both acrylate and methacrylate.

(5) Method for Producing the Copolymer The copolymer used as a pigment dispersant contains the repeating unit derived from the styrene, the repeating unit derived from the unsaturated fatty acid having 12 or more carbon atoms, and the ethylenic unsaturated fatty acid. Repeating units derived from polyalkylene oxides having saturated double bonds and optionally other repeating units can be prepared by known polymerization methods such as emulsion, suspension, precipitation, solution and bulk polymerization. can. Among them, free radical solution polymerization and bulk polymerization are preferred.

The above copolymer may be used as it is as the pigment dispersant in the dispersion liquid of the present embodiment. On the other hand, when a carboxylic acid remains in the copolymer, the carboxylic acid is neutralized with an alkali metal hydroxide, an alkaline earth metal hydroxide, ammonia, or an aminoalcohol to obtain the copolymer. may be used as alkali metal salts, alkaline earth metal salts, ammonium salts, and amine derivatives of

In the above copolymer, a repeating unit derived from styrene, a repeating unit derived from an unsaturated fatty acid having 12 or more carbon atoms, and a repeating unit derived from a polyalkylene oxide having an ethylenically unsaturated double bond are copolymerized. Therefore, it preferably has a comb-shaped structure in which a hydrocarbon chain derived from an unsaturated fatty acid and a polyalkylene oxide chain serve as side chains. Further, the above copolymer may be a block copolymer in which each repeating unit is randomly polymerized, or each repeating unit constitutes a block. Among them, styrene-derived repeating units and unsaturated fatty acid-derived repeating units having 12 or more carbon atoms are used locally because the pigment adsorption becomes stronger locally and the dispersion stability can be improved by thickening the steric protective layer. It is preferable that the repeating units are physically dense, that is, form a block, and that the repeating units derived from the polyalkylene oxide form a block.

In the above copolymer and the like, the molar ratio of each constituent component is such that the average number of repeating units derived from styrene is 1 mol or more per 1 mol of repeating units derived from unsaturated fatty acids, from the viewpoint of dispersibility and dispersion stability. It is preferably 2 mol or more, more preferably 2 mol or more. In the above copolymer and the like, the molar ratio of each constituent component is such that the average number of repeating units derived from styrene is 10 mol or less per 1 mol of repeating units derived from unsaturated fatty acids, from the viewpoint of dispersibility and dispersion stability. It is preferably 5 mol or less, more preferably 5 mol or less. In addition, from the viewpoint of improving compatibility with the dispersion medium and improving the dispersibility and dispersion stability of the pigment, polyalkylene oxide having an ethylenically unsaturated double bond per 1 mol of repeating units derived from unsaturated fatty acids The average number of repeating units derived is preferably 10 mol or more, more preferably 20 mol or more, and even more preferably 30 mol or more. From the viewpoint of improving compatibility with the dispersion medium and improving the dispersibility and dispersion stability of the pigment, polyalkylene oxide-derived polyalkylene oxide having an ethylenically unsaturated double bond per 1 mol of repeating units derived from unsaturated fatty acid The average number of repeating units is preferably 60 mol or less, more preferably 50 mol or less, and even more preferably 40 mol or less. By setting the number of repeating units within the above range, the compatibility with the dispersion medium is enhanced, the polyalkylene oxide chain spreads in the dispersion medium, and the dispersibility and dispersion stability of the pigment can be improved.

Moreover, the molecular weight of the above copolymer is not particularly limited. Among them, the weight average molecular weight is preferably 5,000 or more, more preferably 8,000 or more, and even more preferably 10,000 or more, from the viewpoint of pigment dispersibility, dispersion stability, and dispersion viscosity. From the viewpoint of pigment dispersibility, dispersion stability, and dispersion viscosity, the weight average molecular weight is preferably 30,000 or less, more preferably 20,000 or less, and even more preferably 15,000 or less. In addition, the weight average molecular weight here is calculated|required by standard polystyrene conversion measured by GPC (gel permeation chromatography).

In addition, the above-mentioned copolymer and the like may have an acidic group or a basic group as long as the effect of the present invention is not impaired, but it is preferable that the content is small. As used herein, the term "acidic group" refers to a group that releases H+ in water and exhibits acidity, and includes, for example, a carboxy group and a sulfo group. In the present specification, the term "basic group" refers to a group that accepts H ^{2 +} in water and exhibits basicity, and includes, for example, an amino group.

The content of repeating units containing acidic groups or basic groups is preferably 40% by mass or less, more preferably 30% by mass or less, in the copolymer or the like.

The amine value and acid value of the above copolymer and the like are not particularly limited as long as the pigment dispersant as a whole has an amine value of 20 mgKOH/g or less and an acid value of 10 mgKOH/g or less. Among them, the amine value of the copolymer or the like is preferably 20 mgKOH/g or less, more preferably 17 mgKOH/g or less, from the viewpoint of excellent storage stability. From the viewpoint of excellent storage stability, the acid value of the copolymer or the like is preferably 10 mgKOH/g or less, more preferably 7 mgKOH/g or less.

BYK-9150, BYK-9151 manufactured by BYK-Chemie, etc. can be used as the above copolymer.

The content of the pigment dispersant in the dispersion liquid of the present embodiment is not particularly limited. The content of the pigment dispersant in the entire dispersion is usually 20 parts by mass or more with respect to 100 parts by mass of the pigment, and is preferably 25 parts by mass or more, more preferably 30 parts by mass or more, from the viewpoint of dispersibility and dispersion stability. preferable. The content of the pigment dispersant in the entire dispersion is usually 70 parts by mass or less with respect to 100 parts by mass of the pigment, and is preferably 65 parts by mass or less, more preferably 60 parts by mass or less, from the viewpoint of dispersibility and dispersion stability. preferable. Also, the content of the pigment dispersant in the entire dispersion is preferably 2% by mass or more, more preferably 4% by mass or more. The content of the pigment dispersant in the entire dispersion is preferably 30% by mass or less, more preferably 25% by mass or less. If the content of the pigment dispersant is too small, a steric protective layer may not be formed and the pigment may aggregate. On the other hand, if the content is too large, the viscosity may become high, possibly resulting in poor ejection properties. However, the content of the pigment dispersant is in terms of solid content.

In addition, the dispersion liquid of the present embodiment may further contain other pigment dispersants as necessary as long as the effects of the present invention are not impaired.

Other pigment dispersants are not particularly limited. For example, cationic, anionic, nonionic, amphoteric, silicon, and fluorine surfactants can be used. Examples of surfactants include polymeric surfactants (polymeric dispersants) as exemplified below.

Examples of polymer dispersants include polyester-, polyacrylic-, polyurethane-, polyamine-, and polycaptolactone-based main chains, and side chains containing amino groups, carboxy groups, sulfo groups, hydroxy groups, and the like. A dispersant having a polar group and the like are included. Examples of such polymer dispersants include (co)polymers of unsaturated carboxylic acid esters such as polyacrylic acid esters; (parts) of (co)polymers of unsaturated carboxylic acids such as polyacrylic acid; Amine salts, (partial) ammonium salts and (partial) alkylamine salts; (co)polymers of hydroxyl group-containing unsaturated carboxylic acid esters such as hydroxyl group-containing polyacrylic acid esters, and knitted products thereof; polyurethanes; unsaturated polyamides ; polysiloxanes; long-chain polyaminoamide phosphates; polyethyleneimine derivatives (amides obtained by the reaction of poly (lower alkyleneimine) and free carboxyl group-containing polyesters and their bases); polyallylamine derivatives (polyallylamine and a reaction product obtained by reacting one or more compounds selected from three types of compounds: polyesters, polyamides, or cocondensates of esters and amides (polyesteramides) having free carboxyl groups; be done.

Commercially available products can be used as such polymeric dispersants, and examples thereof include SOLSPERSE manufactured by Lubrizol, DISPERBYK manufactured by BYK-Chemie, and EFKA manufactured by Efka Additives.

In the dispersion liquid of the present embodiment, the content of the other pigment derivative is not particularly limited as long as it does not impair the effects of the present invention. It is preferably not contained.

[Active energy ray-polymerizable monomer]
The dispersion liquid of the present embodiment may contain an active energy ray-polymerizable monomer. Examples of active energy ray-polymerizable monomers include monomer A): a monofunctional monomer represented by the following general formula (1), and/or monomer B): a polyfunctional monomer represented by the following general formula (2). can be mentioned. In the present specification, "containing a monomer such as monomer A)" means not only containing a single monomer such as monomer A) having the same molecular structure, but also containing two or more monomers having different molecular structures. The concept also includes the inclusion of monomers such as monomer A).

（式中、Ｒ^１は含酸素複素環構造を有する官能基である。Ｒ^２は炭素数１以上５以下のアルキレン基を示す。Ｒ^３は水素原子又はメチル基を示す。Ｒ^４は水素原子を示す。）

(In the formula, R ¹ is a functional group having an oxygen-containing heterocyclic structure. R ² represents an alkylene group having 1 to 5 carbon atoms. R ³ represents a hydrogen atom or a methyl group. R ⁴ represents a hydrogen atom. indicates.)

R ⁴ -CH=CR ¹ -COOR ² -O-CH=CH-R ³ (2)
(In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents a divalent organic residue having 2 to 20 carbon atoms, R ³ represents a hydrogen atom or a monovalent residue having 1 to 11 carbon atoms. represents an organic residue, and ^R4 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

Monomer A) represented by general formula (1) and monomer B) represented by general formula (2) have low viscosities. Therefore, the active energy ray-curable ink composition produced from the dispersion liquid containing the monomer A) represented by the general formula (1) and the monomer B) represented by the general formula (2) is It is an active energy ray-curable ink composition with low viscosity and high ejection stability.

In addition, since the monofunctional monomer represented by the general formula (1) and the polyfunctional monomer represented by the general formula (2) have a low odor, the active energy ray-curable ink composition containing these monomers has a low odor. small. In the present specification, the expression that the odor of the active energy ray-curable ink composition is low means that the odor of the active energy ray-curable ink composition itself is low. In the case of the ink composition, when handling the active energy ray-curable ink composition, when forming an image on a substrate using the active energy ray-curable ink composition, or when using the active energy ray-curable ink composition When manufacturing printed matter using , workers can concentrate on their work without worrying about odors, and even workers with sensitive noses can work without masks. There is an advantage that

Examples of monomers A) are tetrahydrofurfuryl acrylate (THFA), trimethylolpropane formal acrylate (CTFA), (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate, (2- methyl-2-isobutyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, (cyclohexanespiro-2-(1,3-dioxolan-4-yl))methyl (meth)acrylate and the like. It is possible, but not limited to this. In the above first embodiment, the monomer A) is preferably a monofunctional monomer represented by the above general formula (3). Among the monomers A) represented by the above general formula (3), Tetrahydrofurfuryl acrylate (THFA) and (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate are preferred from the viewpoint of low viscosity and extremely low odor, and tetrahydrofurfuryl acrylate ( THFA) is most preferred.

As monofunctional monomers other than monomer A), conventionally known monofunctional monomers can be used. , isobornyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, γ-butyrolactone acrylate, cresol acrylate, 2-acryloyloxyethyl phthalate, 2-acryloyloxyethyl-2-hydroxy Ethyl phthalate, 2-acryloyloxyethylhexahydrophthalate, 2-acryloyloxypropyl phthalate, paracumylphenoxyethylene glycol acrylate, nonylphenoxypolyethylene glycol acrylate, 1-adamantyl acrylate, cyclohexyl acrylate, 3-3-5-trimethylcyclohexane Acrylate, 2-hydroxy-3-phenoxypropyl acrylate, acryloylmorpholine, N-vinylcaprolactam, imidoacrylate, isooctyl acrylate, tridecyl acrylate, lauryl acrylate, 2-hydroxyethyl acrylate, stearyl acrylate, isodecyl acrylate, caprolactone acrylate , methoxypolyethylene glycol acrylate, methoxypolypropylene glycol acrylate, 2-methoxyethyl acrylate, ethylcarbitol acrylate, 2-ethylhexyl acrylate, and those having various modifications such as alkoxy modification and caprolactone modification to these acrylates. can be done. Monofunctional monomers other than monomer A) are not essential in the dispersion of the present embodiment, but when monofunctional monomers other than monomer A) are used, from the viewpoint of low odor and low viscosity, 4- It is preferred to use alkylcycloalkyl acrylates such as t-butylcyclohexyl acrylate.

Specific examples of the monomer B) represented by the general formula (2) include, for example, 2-vinyloxyethyl (meth)acrylate, 3-vinyloxypropyl (meth)acrylate, and 1-methyl-2 (meth)acrylate. -vinyloxyethyl, 2-vinyloxypropyl (meth)acrylate, 4-vinyloxybutyl (meth)acrylate, 1-methyl-3-vinyloxypropyl (meth)acrylate, 1-vinyloxymethylpropyl (meth)acrylate, 2-methyl-3-vinyloxypropyl (meth)acrylate, 1,1-dimethyl-2-vinyloxyethyl (meth)acrylate, 3-vinyloxybutyl (meth)acrylate, 1-methyl-2-(meth)acrylate vinyloxypropyl, 2-vinyloxybutyl (meth)acrylate, 6-vinyloxyhexyl (meth)acrylate, p-vinyloxymethylphenylmethyl (meth)acrylate, m-vinyloxymethylphenylmethyl (meth)acrylate, o-vinyloxymethylphenylmethyl (meth)acrylate, 2-(vinyloxyethoxy)ethyl (meth)acrylate, 2-(vinyloxyisopropoxy)ethyl (meth)acrylate, 2-(meth)acrylate vinyloxyethoxy)propyl, 2-(vinyloxyethoxy)isopropyl (meth)acrylate, 2-(vinyloxyisopropoxy)propyl (meth)acrylate, 2-(vinyloxyisopropoxy)isopropyl (meth)acrylate, 2-(vinyloxyethoxyethoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxyisopropoxy)ethyl (meth)acrylate, 2-(vinyloxyisopropoxyethoxy)ethyl (meth)acrylate, (meth)acrylate 2-(vinyloxyisopropoxyisopropoxy)ethyl acrylate, 2-(vinyloxyethoxyethoxy)propyl (meth)acrylate, 2-(vinyloxyethoxyisopropoxy)propyl (meth)acrylate, (meth)acrylic acid 2-(vinyloxyisopropoxyethoxy)propyl, 2-(vinyloxyisopropoxyisopropoxy)propyl (meth)acrylate, 2-(vinyloxyethoxyethoxy)isopropyl (meth)acrylate, 2-(meth)acrylate (Vinyloxyethoxyisopropoxy) isopropyl, 2-(vinyloxyisopropoxyethoxy) isopropyl (meth)acrylate, 2-(vinyloxyisopropoxyisopropoxy) isopropyl (meth)acrylate, ( 2-(vinyloxyethoxyethoxyethoxy)ethyl meth)acrylate, 2-(vinyloxyethoxyethoxyethoxyethoxy)ethyl (meth)acrylate, 2-(isopropenoxyethoxy)ethyl (meth)acrylate, (meth)acrylate 2-(isopropenoxyethoxyethoxy)ethyl acrylate, 2-(isopropenoxyethoxyethoxyethoxy)ethyl (meth)acrylate, 2-(isopropenoxyethoxyethoxyethoxyethoxy)ethyl (meth)acrylate, (meth) ) polyethylene glycol monovinyl ether acrylate and polypropylene glycol monovinyl ether (meth)acrylate.

Among the above, 2-vinyloxyethyl (meth)acrylate, 3-vinyloxypropyl (meth)acrylate, 1-methyl-2-vinyloxyethyl (meth)acrylate, 2-vinyloxypropyl (meth)acrylate, ( 4-vinyloxybutyl meth)acrylate, 5-vinyloxypentyl (meth)acrylate, 6-vinyloxyhexyl (meth)acrylate, 4-vinyloxymethylcyclohexylmethyl (meth)acrylate, p-(meth)acrylate Vinyloxymethylphenylmethyl, 2-(vinyloxyethoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxyethoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxyethoxyethoxy)ethyl (meth)acrylate is preferred.

Among these, 2-(vinyloxyethoxy)ethyl (meth)acrylate is preferable because of its low viscosity, high flash point, and excellent curability of the active energy ray-polymerizable monomer. In addition, 2-(vinyloxyethoxy)ethyl (meth)acrylate is more preferable because of its excellent reactivity.

Examples of 2-(vinyloxyethoxy)ethyl (meth)acrylate include 2-(2-vinyloxyethoxy)ethyl (meth)acrylate and 2-(1-vinyloxyethoxy)ethyl (meth)acrylate. , 2-(vinyloxyethoxy)ethyl acrylate includes 2-(2-vinyloxyethoxy)ethyl acrylate and 2-(1-vinyloxyethoxy)ethyl acrylate. Monomer B) may be used singly or in combination of two or more.

As polyfunctional monomers other than monomer B), conventionally known polyfunctional monomers can be used. Acrylates, polyalkylene glycol diacrylate, alkoxylated bisphenol A diacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, 1,4-butanediol diacrylate, tetraethylene glycol Diacrylates, dimethyloltricyclodecane diacrylates, trimethylolpropane triacrylates, pentaerythritol triacrylates, glycerol triacrylates, and (meth)acrylates with different modified numbers, different modified types, and different structures can be mentioned.

The total content of the compounds having ethylenically unsaturated double bonds is not particularly limited. Among them, from the viewpoint of curability, the lower limit of the content of the compound having an ethylenically unsaturated double bond in the entire dispersion of the present embodiment is preferably 10% by mass or more, and is 25% by mass or more. is more preferable, and 40% by mass or more is particularly preferable. The upper limit is preferably 93% by mass or less, more preferably 90% by mass or less, and particularly preferably 86% by mass or less.

In addition, in this embodiment, a non-reactive polymer component may be further contained. Examples of such polymer components include acrylic resins and cellulose acetate butyrate resins.

[Polymerization inhibitor]
The dispersion liquid of this embodiment may contain a polymerization inhibitor as needed. The polymerization inhibitor is not particularly limited. Polymerization inhibitors such as butylhydroquinone, phenothiazines, and nitrosamines can be used.

(Manufacturing method of dispersion liquid)
In the dispersion liquid of the present embodiment, the method for producing the dispersion liquid is not particularly limited, but usually includes a pigment dispersion step.

In the pigment dispersion step, for example, an active energy ray-polymerizable monomer is used as a dispersion medium, a pigment, a pigment dispersant, and optionally other components are added, stirred with a dissolver or the like, and then zirconia beads are produced using a bead mill. and so on. If necessary, zirconia beads or the like having a relatively large bead diameter may be used for pre-dispersion prior to the above dispersion. The dispersion liquid of the present embodiment can be obtained by filtering the obtained dispersion with a membrane filter or the like, if necessary.

When a compound having a polyalkylene oxide chain and/or an aliphatic hydrocarbon chain having 12 or more carbon atoms is used as another component, the compound may be added during pigment dispersion, or added after pigment dispersion. In either case, the ink composition can be made to have excellent liquid repellency against the ink ejection surface.

<Ink composition>
Ink compositions can be prepared from the dispersions of the embodiments described above. As described above, the dispersion liquid of the above embodiment has excellent curability because the product of absorbance at wavelengths from 360 nm to 400 nm and the hue of the cured film are adjusted, and the hue is suitable as a yellow ink composition. is an ink composition that forms a cured film of Furthermore, it is preferable to contain a photoinitiator.

The ink composition of the present embodiment can be discharged by a conventionally known method such as an offset method, a gravure method, a spray method, or a brush coating method.

[Photoinitiator]
The photopolymerization initiator is preferably a photopolymerization initiator that accelerates the polymerization reaction of the active energy ray-polymerizable monomer by irradiation with light containing light having a wavelength of 360 nm to 400 nm. Such a photopolymerization initiator is an excellent photopolymerization initiator in terms of curing speed, availability of irradiation equipment, price, and the like. In addition, since the dispersion liquid described above has a product of absorbance of 40 or less at a wavelength of 360 nm to 400 nm, the active energy ray-polymerizable monomer can be obtained by irradiating with a light beam containing light at a wavelength of 360 nm to 400 nm. A photopolymerization initiator that accelerates the polymerization reaction of can be particularly preferably used. Examples of such photopolymerization initiators include photopolymerization initiators that absorb light with a wavelength of 360 nm to 400 nm.

As the photopolymerization initiator, conventionally known photopolymerization initiators can be used. Specific examples of polymerization initiators include aromatic ketones including thioxanthone, α-aminoalkylphenones, α-hydroxyketones, acylphosphine oxides, aromatic onium salts, organic peroxides, and 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 photopolymerization initiator related to the present embodiment may be an amount capable of appropriately initiating the photopolymerization reaction of the active energy ray-polymerizable monomer, and is preferably 1.0% by mass or more with respect to the entire ink composition. It is preferably 3.0% by mass or more, and more preferably 3.0% by mass or more. Moreover, it is preferably 20.0% by mass or less with respect to the entire ink composition.

(other ingredients)
The ink composition of this embodiment may further contain other components. Other components include, for example, sensitizers and the like in addition to those exemplified in the dispersant of the above embodiment.
The storage stability of the ink composition of the present embodiment can be further improved by containing a polymerization inhibitor.

(Viscosity and Surface Tension of Ink Composition)
The viscosity of the ink composition of the present embodiment is preferably 30 mPa·s or less at 25° C., more preferably 25 mPa·s or less, from the viewpoint of ejection property and ejection stability. Moreover, the viscosity of the ink composition of the present embodiment is preferably 5 mPa·s or more.

Further, the surface tension of the ink composition of the present embodiment is preferably 20 mN/m or more at 25° C. from the viewpoints of inkjet ejection property, ejection stability, and leveling property to the substrate. Moreover, the surface tension of the ink composition of the present embodiment is preferably 40 mN/m or less.

(Content ratio of each component in the ink composition)
In the ink composition of the present embodiment, the content of the pigment is preferably 0.1% by mass or more, more preferably 0.15% by mass or more, based on the total amount of the ink composition, from the viewpoint of achieving both dispersibility and coloring power. Preferably, 0.2% by mass or more is more preferable. The content of the pigment is preferably 40% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less relative to the total amount of the ink composition, from the viewpoint of achieving both dispersibility and coloring power.

The content of the pigment dispersant in the ink composition is not particularly limited, and varies depending on the type of pigment, but the pigment dispersant is usually 20 parts by mass or more per 100 parts by mass of the pigment. Alternatively, it is 70 parts by mass or less with respect to 100 parts by mass of the pigment. From the viewpoint of dispersibility and dispersion stability, it is preferably 25 parts by mass or more, more preferably 30 parts by mass or more. From the viewpoint of dispersibility and dispersion stability, 65 parts by mass or less is preferable, and 60 parts by mass or less is more preferable.

Moreover, the content of the active energy ray-polymerizable monomer in the ink composition is not particularly limited. Among them, from the viewpoint of curability, the content of the active energy ray-polymerizable monomer in the entire ink composition is preferably 30% by mass or more, more preferably 45% by mass or more, and 60% by mass or more. It is even more preferable to have From the viewpoint of curability, the content of the active energy ray-polymerizable monomer in the entire ink composition is preferably 95% by mass or less, more preferably 90% by mass or less.

The content of the pigment dispersant in the ink composition is not particularly limited. The content of the pigment dispersant in the entire ink composition is preferably 0.02% by mass or more, more preferably 0.03% by mass or more, and even more preferably 0.06% by mass or more. . When the content of the pigment dispersant is 0.02% by mass or more, aggregation of the pigment can be suppressed. The content of the pigment dispersant in the entire ink composition is preferably 24% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less. When the content of the pigment dispersant is 24% by mass or less, an increase in viscosity is suppressed and ejection stability is improved.

In the ink composition, a copolymer having a repeating unit derived from styrene, a repeating unit derived from an unsaturated fatty acid having 12 or more carbon atoms, and a repeating unit derived from a polyalkylene oxide having an ethylenically unsaturated double bond, Pigment dispersion containing one or more selected from the group consisting of the alkali metal salt of the copolymer, the alkaline earth metal salt of the copolymer, the ammonium salt of the copolymer, and the amine derivative of the copolymer The content of the agent is not particularly limited. The content of the copolymer or the like in the entire ink composition is preferably 0.02% by mass or more, more preferably 0.03% by mass or more, and more preferably 0.06% by mass or more. more preferred. When the content of the copolymer or the like in the entire ink composition is 0.02% by mass or more, aggregation of the pigment can be suppressed. The content of the copolymer or the like in the entire ink composition is preferably 24% by mass or less, preferably 20% by mass or less, and more preferably 10% by mass or less. When the content of the copolymer or the like in the entire ink composition is 24% by mass or less, the increase in viscosity is suppressed and the ejection stability is improved. The contents of are each in terms of solid content.

<Method for producing active energy ray-curable ink composition>
The method for producing the ink composition of the present embodiment is not particularly limited, and conventionally known methods can be used. In addition, when using a granular coloring material, a granular matting agent, etc., using a dispersing machine, the active energy ray polymerizable monomer, dispersing agent, etc. are dispersed, and then, if necessary, a photopolymerization initiator, surface An ink composition is obtained by adding a modifier and the like, stirring uniformly, and filtering through a filter.

<Method for manufacturing laminate>
The laminate of this embodiment is produced by printing the ink composition of the above embodiment onto a substrate, preferably by an inkjet method, and then curing it with a light beam containing light having a wavelength of 360 nm to 400 nm. . 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 because it can handle small lots of many products. Moreover, when printing by an inkjet method, printing may be performed with the inkjet head heated, or printing may be performed at room temperature. When the ink composition of the present embodiment contains monomer A) and/or monomer B), which have extremely low viscosity even in a room temperature environment, the ink composition has a low viscosity even in a room temperature environment. Therefore, it is possible to print on the substrate without heating the inkjet head.

Additionally, the ink composition can be used to form an image on a substrate. For example, an ink set of an active energy ray-curable ink composition containing coloring materials of various shades is prepared, and after printing by an inkjet method, the ink composition is cured to form various images on the substrate. can be formed. An 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. As used herein, the term "image" means a decorative image that can be visually recognized, including single-color or multi-color characters, charts, figures, symbols, photographs, and the like. Patterns such as stone grains, cloth grains, sand grains, geometric patterns, letters, and the like are also included.

[Base material]
The substrate is not particularly limited, and for example, any of coated paper, non-coated paper, absorbers such as cloth, and non-absorbent substrates can be used. Specifically, non-coated paper includes dry paper, medium-quality paper, high-quality paper, and coated paper includes coated paper, art paper, cast paper, lightweight coated paper, lightly coated paper, fabric, etc. Examples of the body include cotton, synthetic fiber fabric, silk, hemp, fabric, non-woven fabric, leather, etc. Non-absorbent substrates include polyester resin, polypropylene synthetic paper, vinyl chloride resin, polyimide resin, metal, and metal. Examples include foil-coated paper, glass, synthetic rubber, natural rubber, and the like.

[Curing by active energy rays]
The active energy ray for forming a cured film (hereinafter sometimes referred to as a “cured film”) obtained by curing the ink composition of the above embodiment is a light ray containing light with a wavelength of 360 nm to 400 nm. preferable. The light source is not particularly limited as long as it can irradiate a light beam containing light with a wavelength of 360 nm to 400 nm. A light, an LED lamp, etc. are mentioned. The ink composition can be instantaneously cured by irradiating the active energy ray using these light sources so that the integrated light quantity is 100 mJ/cm ² or more, preferably 200 mJ/cm ² or more.

The light source is not particularly limited as long as it is a light source that can irradiate a light beam containing light having a wavelength of 360 nm to 400 nm. More preferably, LED lamps are used.

The thickness of the cured film is preferably 1 μm or more. Moreover, the thickness of the cured film is preferably 100 μm or less. A thickness of 1 μm or more is more preferable because the color density of the cured film containing the colorant does not decrease, and physical properties such as adhesion and elongation are improved and design and decorative properties are reduced. A thickness of 100 μm or less is more preferable because the ink composition can be sufficiently cured in a shorter time when the ink composition is irradiated with an active energy ray.

The thickness of the cured film was measured by applying the ink composition of the above-described embodiment to a PET film (A4300, manufactured by Toyobo Co., Ltd.) under the same coating conditions as for the prepared cured film, and measuring the thickness of the cured film obtained. Thickness can be measured with a micrometer. In the present specification, the thickness of the cured film refers to the thickness obtained by measuring 10 points per sample and averaging these values (average thickness). The same applies to the protective layer and primer described later.

[Cured film]
The cured film formed from the ink composition of the above embodiment can be used as a decorative layer. It can also be used as an overcoat layer for protecting the cured film. Furthermore, it can also be used as a primer layer for improving the adhesion between the substrate surface and the cured film by forming it between them.

When forming an overcoat layer or a primer layer on a base material, any method may be used to form these layers, for example, spray coating, coating using a towel, sponge, nonwoven fabric, tissue, or the like. , dispenser, brush coating, gravure printing, flexo printing, silk screen printing, inkjet, thermal transfer, and the like.

The ink composition of the above embodiment (yellow ink composition) and other colors (cyan ink composition, magenta ink composition, black ink composition, etc.) are combined and ejected at a wavelength of 360 nm or more. An image can be formed on the substrate by irradiation with actinic energy rays, such as rays containing light up to 400 nm. Furthermore, by adjusting conditions such as the discharge amount of the ink composition and the time from the discharge of the ink composition to the irradiation of the active energy ray, it is possible to impart design properties other than images to the cured film. For example, unevenness can be imparted by increasing or decreasing the amount of one ejection depending on the ejection location, and unevenness can be obtained by repeating ejection of the ink composition and irradiation of the active energy ray at the same location. A difference can also be given. Imaging methods for forming such images and/or relief images are also within the scope of the present invention.

[Overcoat layer]
For the purpose of further improving the durability of the laminate, an overcoat layer made of a conventionally known overcoat agent or the ink composition of the above embodiment is applied to the surface of the cured film of the ink composition of the above embodiment. An overcoat layer may be further formed by using an ink composition having the same composition but containing no pigment as an overcoat agent. The overcoat layer is not limited to being formed on the surface of the layer composed of the cured film of the ink composition, and may be formed directly on the surface of the substrate, or may be formed directly on the surface of the substrate. It may be formed on the surface of the layer.

As the overcoat agent, an ink composition having the same composition as the ink composition of the above-described embodiment, but containing no pigment, can be preferably used. An overcoat layer is formed on a cured film using the ink composition of the above embodiment by using an overcoat agent using an ink composition having the same composition as the ink composition of the above embodiment and to which no pigment is added. In this case, since the cured film and the overcoat layer have the same composition, their adhesion is extremely high.

The thickness of the overcoat layer is preferably 1 μm or more. A thickness of 1 μm or more is preferable because the cured film can be appropriately protected. Moreover, the thickness of the overcoat layer is preferably 100 μm or less. A thickness of 100 μm or less is preferable because the drying time for forming the overcoat layer can be shortened and the productivity can be improved.

Further, when the overcoat layer is formed, the conditions such as the discharge amount of the ink composition and the time from the discharge of the ink composition to the irradiation of the active energy ray are adjusted, thereby imparting a design property to the overcoat layer. can also For example, it is possible to form a three-dimensional and highly designed overcoat layer with unevenness by making the surface matte or glossy, or intentionally making the film thickness of the surface non-uniform. Specifically, the surface can be made glossy by irradiating the active energy ray after a predetermined time has elapsed after the ink composition is ejected, and the surface can be made glossy by irradiating the active energy ray immediately after ejection. It can be made matte. In addition, irregularities can be imparted by increasing or decreasing the ejection amount per ejection depending on the ejection location, and by repeating the ejection of the ink composition and the irradiation of the active energy ray at the same location, it is possible to create a contrast with other locations. A difference in unevenness can also be given.

The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these descriptions.

<Preparation of Dispersion (Examples, Comparative Examples)>
(Examples 1-3)
P.I. Y. 138 (with derivatization) (Pigment Yellow 138 a pigment containing a quinophthalone-based pigment and CI Pigment Yellow 138 having a sulfonic acid group (—SO ₃ H) (a pigment derivative containing a quinophthalone-based pigment derivative)) 12 parts by mass, THFA (tetrahydrofurfuryl acrylate (monofunctional monomer and monomer A corresponding to formula (1))) which is an active energy ray-polymerizable monomer as a dispersion medium, and BYK-9151 (Bik Chemie) as a pigment dispersant and a pigment dispersant (solid content 70% PO modified - 2-neopentyl glycol diacrylate diluted product) manufactured by Co., Ltd. After mixing with a dissolver or the like, pre-dispersing with φ1.2 mm zirconia beads for 1 hour. After that, dispersion was performed for 2 hours with zirconia beads of φ0.3 mm to prepare a dispersion liquid. The contents of the pigment dispersant and the polymerizable monomer are shown in Table 1.

"PY 138 (with derivatization)" was synthesized as follows. 374.76 parts by mass of 11% by mass fuming sulfuric acid were stirred while cooling to 10°C, and C.I. I. 74.96 parts by mass of Pigment Yellow 138 (a pigment containing a quinophthalone-based pigment) was added. Then, it was stirred at 90° C. for 6 hours. The reaction solution was added to 1,600 parts by mass of ice water, stirred for 15 minutes, and the precipitate was filtered. The wet cake obtained was washed with 800 ml of water three times. The wet cake was vacuum dried at 80° C. to obtain 81.55 parts by mass of a yellow product (PY 138 (with derivatization)). The mass spectrometry result of this yellow product (PY138 (with derivatization)) by TOF-MS is the molecular weight (Mw = 774) of the monosulfonic acid derivative (n = 1) of PY138 represented by the following formula. was consistent.

"BYK-9151" is a repeating unit derived from styrene, a repeating unit derived from an unsaturated fatty acid having 16 and 18 carbon atoms, and a repeating unit derived from an unsaturated fatty acid having an ethylenically unsaturated double bond 1 mol. A copolymer having 10 mol or more and 60 mol or less of polyalkylene oxide-derived repeating units, a copolymer alkali metal salt, a copolymer alkaline earth metal salt, a copolymer ammonium salt, and A pigment dispersant containing one or more selected from the group consisting of amine derivatives of copolymers.

(Example 4)
In the same manner as in Examples 1 to 3, except that the dispersant was changed from BYK-9151 to BYK-9150 (pigment dispersant manufactured by BYK Chemie (solid content 70% PO-modified-2-neopentyl glycol diacrylate diluted product)). A dispersion was prepared.

"BYK-9150" is a repeating unit derived from styrene, a repeating unit derived from an unsaturated fatty acid having 16 and 18 carbon atoms, and a repeating unit derived from an unsaturated fatty acid having an ethylenically unsaturated double bond 1 mol. A copolymer having 10 mol or more and 60 mol or less of polyalkylene oxide-derived repeating units, a copolymer alkali metal salt, a copolymer alkaline earth metal salt, a copolymer ammonium salt, and A pigment dispersant containing one or more selected from the group consisting of amine derivatives of copolymers.

(Example 5)
The pigment is P.I. Y. 138 to P.S. Y. A dispersion was prepared in the same manner as in Example 1, except that Pigment Yellow 150 (Pigment Yellow 150, a pigment containing a yellow pigment that is not a quinophthalone pigment) was used.

(Comparative example 1)
A dispersion was prepared in the same manner as in Example 1, except that the dispersant was changed from BYK-9151 to Solspers 32000.

"Solspers 32000" is a pigment dispersant manufactured by Lubrizol, Inc., which does not correspond to the above pigment dispersants.

(Comparative example 2)
A dispersion was prepared in the same manner as in Example 1, except that the dispersant was changed from BYK-9151 to Solspers 33000.

"Solspers 33000" is a pigment dispersant manufactured by Lubrizol, Inc., which does not correspond to the above pigment dispersants.

(Comparative Example 3)
The pigment is P.I. Y. 138 to P.S. Y. A dispersion was prepared in the same manner as in Example 1, except that Pigment Yellow 155 (Pigment Yellow 155, a pigment containing a yellow pigment that is not a quinophthalone pigment) was used.

<Preparation of Ink Composition (Examples, Comparative Examples)>
Ink compositions of Examples and Comparative Examples were produced using the dispersions of Examples and Comparative Examples. Specifically, each material was mixed in the ratio shown in Table 2 and stirred at room temperature (20 to 25° C.) for 1 hour. After that, it was confirmed that there was no undissolved residue. Thereafter, filtration was performed using a membrane filter to prepare active energy ray-curable ink compositions of Examples and Comparative Examples.

In Table 2, "VEEA" is 2-(2-vinyloxyethoxy)ethyl acrylate (monomer B) which is a bifunctional monomer and corresponds to formula (2)) manufactured by Nippon Shokubai Co., Ltd.

In Table 2, "THFA" is tetrahydrofurfuryl acrylate (monomer A which is a monofunctional monomer and corresponds to formula (1))).

In Table 2, "TBCH" is 4-tert-butylcyclohexyl acrylate (monofunctional monomer other than monomer A).

In Table 2, "TMPTA" is trimethylolpropane triacrylate (trifunctional monomer).

[Absorbance test]
An absorbance test was conducted using the dispersions of Examples and Comparative Examples. Specifically, the dispersions of Examples and Comparative Examples were diluted 2400-fold with ethyl diglycol acetate, and the absorbance at wavelengths from 360 nm to 400 nm was measured using UV-1800 manufactured by Shimadzu Corporation, and integrated. , the absorbance area (product of absorbance) in the wavelength range from 360 nm to 400 nm was determined. The absorbances of the dispersions of Example 1 and Comparative Example 3 are shown in FIG.

[Hue test]
A hue test was conducted using the ink compositions of Examples and Comparative Examples. Specifically, IRGACURE TPO (a photopolymerization initiator manufactured by BASF, having a wavelength of 360 nm Photopolymerization initiator for acylphosphine oxides that promotes the polymerization reaction of active energy ray-polymerizable monomers by irradiating with light rays containing light from to 400 nm) 10 parts by mass, TegoRad 2010 (Evonik Degussa Japan Co., Ltd. surface conditioner) ) to prepare an ink composition by mixing 1 part by weight. Then, it was applied to 10 μm (cured state) on untreated PET (Lumirror 60 μm) using a bar coater (#7) and cured to form a cured film. Based on JIS-Z8722:2009, the cured film was measured for L ^* a ^* b ^* using an x-rite eXact manufactured by X-Rite under the conditions of a D50 light source and a 2° viewing angle to obtain the b ^* value. . Table 2 shows the results. A shuttle type UV curing device manufactured by ITEC System Co., Ltd. was used for curing, and an LED-UV lamp manufactured by ITEC System Co., Ltd. (peak wavelength: 385 nm) was used as a light source.

(Evaluation criteria)
○: b ^* value is 65 or more ×: b ^* value is less than 65

[Curability test]
A curability test was conducted using the ink compositions of Examples and Comparative Examples. Specifically, an ink composition was produced in the same manner as described above, coated on untreated PET (Lumirror 60 μm) to a thickness of 10 μm (cured state) using a bar coater (#7), and irradiated with an LED lamp to form an ink composition. The accumulated amount of light for curing was investigated.

(Evaluation criteria)
OK: Cured at cumulative light intensity of 200 mJ/cm ² NG: Not cured at cumulative light intensity of 200 mJ/cm ²

From Table 1, the dispersion liquid of the present invention is an ink composition having excellent curability even if it is a dispersion liquid for an ink composition containing a yellow pigment, and has a hue suitable for a yellow ink composition. It can be seen that it is possible to produce ink compositions that form films.

Claims (12)

A dispersion liquid for an ink composition that is cured by an active energy ray and contains a yellow pigment and a pigment dispersant,
The yellow pigment is
Pigment Yellow 138, and derivatives of Pigment Yellow 138;
or
Pigment Yellow 150,
The pigment dispersant has an amine value of 20 mgKOH/g or less and an acid value of 10 mgKOH/g or less, and includes a repeating unit derived from styrene and a repeating unit derived from an unsaturated fatty acid having 12 or more carbon atoms, A copolymer having a repeating unit derived from a polyalkylene oxide having an ethylenically unsaturated double bond, an alkali metal salt of the copolymer, an alkaline earth metal salt of the copolymer, and an ammonium salt of the copolymer , and one or more selected from the group consisting of amine derivatives of the copolymer,
In absorbance measurement, the product of absorbance from wavelength 360 nm to 400 nm defined by the following formula is 40 or less,

(Wherein, λ means wavelength (unit: nm) f(λ)=A _λ =−log ₁₀ (I/I ₀ ). A _λ is absorbance at wavelength λ, I ₀ is at wavelength λ and I means the transmitted light intensity at wavelength λ.)
A dispersion having a b ^* value of 65 or more as measured under the conditions of a D50 light source and a viewing angle of 2° based on JIS-Z8722:2009 for a cured film prepared under the following cured film preparation conditions.
(Curing conditions for forming a cured film: The ink composition containing the dispersion liquid and the photopolymerization initiator is cured by irradiating it with a light beam containing light having a wavelength of 360 nm to 400 nm.) 2. The dispersion according to claim 1, which is used for an ink composition which is cured by light containing light having a wavelength of 360 nm to 400 nm. Furthermore, as an active energy ray-polymerizable monomer,
Monomer A): a monofunctional monomer represented by the following general formula (1) and/or monomer B)
3. The dispersion according to claim 1 or 2 , containing a polyfunctional monomer represented by the following general formula (2).

(In formula (1), R ¹ is a functional group having an oxygen-containing heterocyclic structure. R ² represents an alkylene group having 1 to 5 carbon atoms. R 3 represents a hydrogen atom or a methyl group. R ⁴ represents indicates a hydrogen atom.)
R ⁴ -CH=CR ¹ -COOR ² -O-CH=CH-R ³ (2)
(In formula (2), R ¹ represents a hydrogen atom or a methyl group, R ² represents a divalent organic residue having 2 to 20 carbon atoms, R ³ represents a hydrogen atom or a It represents a monovalent organic residue, and ^R4 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.) An ink composition containing the dispersion according to any one of claims 1 to 3 . 5. The ink composition according to claim 4 , further comprising a photopolymerization initiator. 6. The active energy ray-curable ink composition according to claim 4 or 5 , which is cured by light rays containing light having a wavelength of 360 nm to 400 nm. 7. The ink composition according to any one of claims 4 to 6 , which is used as an inkjet ink. A laminate comprising a substrate and a cured ink film layer, which is a cured film of the ink composition according to any one of claims 4 to 7 , formed on a substrate. An image forming method for forming an image and/or a relief image on a substrate using the ink composition according to any one of claims 4 to 7 . 10. The image forming method according to claim 9 , wherein the image and/or the concave-convex image are formed by irradiating the substrate with a light beam containing light having a wavelength of 360 nm to 400 nm. A method for producing a printed matter, comprising forming an image and/or an uneven image on a substrate using the ink composition according to any one of claims 4 to 7 . 12. The image forming method according to claim 11 , wherein the image and/or the uneven image are formed by irradiating the substrate with light containing light having a wavelength of 360 nm to 400 nm.

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