JP6911752B2 - Pigment dispersion and ink composition using it - Google Patents

Description

The present invention provides dispersibility and storage stability not only for applications with relatively large pigment particle diameters such as offset inks, flexographic inks, and gravure inks, but also for applications with finer pigment particle diameters such as inkjet inks and resist inks. It is an object of the present invention to provide a pigment dispersion which exhibits excellent performance in heat resistance and chemical resistance.

In general, when a pigment dispersion is produced, it is known that it is difficult to stably disperse the pigment at a high concentration, which causes various problems in the production process and the product itself.

For example, pigment dispersions containing pigments consisting of fine particles often exhibit high viscosities, making it difficult to remove and transport the product from the disperser, and in the worst case, gelation during storage. It can even be difficult to use. Further, on the surface of the developed color of the pigment dispersion, poor conditions such as deterioration of gloss and poor leveling occur. Further, when different kinds of pigments are mixed and used, color unevenness and a remarkable decrease in coloring power may appear in the colored matter due to a phenomenon such as color separation due to aggregation and precipitation.

Therefore, a dispersant is generally used to maintain a good dispersed state. The dispersant has a structure of a part that adsorbs to the pigment and a part that has a high affinity for the solvent that is the dispersion medium, and the performance of the dispersant is determined by the balance of these two functional parts. Various dispersants are used according to the surface condition of the pigment to be dispersed, but for pigments having a surface biased to basicity, dispersants having an acidic functional group that electrostatically adsorbs. Is commonly used. In this case, the acidic functional group becomes the adsorption site of the pigment.

However, on the other hand, dispersants having acidic functional groups are often not effective for pigments having acidic surfaces. Therefore, a basic dispersant is used for a pigment having an acidic surface as in Patent Document 1, but this dispersant does not have a crosslinkable functional group, and various resistances of the ink composition containing the dispersant are used. (Chemical resistance, heat resistance, etc.) were insufficient.

Further, as shown in Patent Document 2, although various resistances are increased by combining a specific dispersant containing a heat-crosslinkable functional group and a specific basic dispersant, the chemical resistance of the ink composition is still inferior. There was the issue of being sufficient.

Japanese Unexamined Patent Publication No. 2004-12813 Japanese Unexamined Patent Publication No. 2016-170370

The present invention has been made in view of the above situation, and an object of the present invention is to provide a pigment dispersion having excellent dispersibility and an ink composition having excellent chemical resistance and heat resistance.

As a result of diligent studies, the present inventors have found that the above problems can be solved by an ink composition using a resin-type pigment dispersant (A), which is a polymer having a structural unit containing an oxazolidinyl group in the pigment dispersion. , The present invention has been completed.

That is, the present invention is a pigment dispersion containing a pigment, a pigment dispersant (A), and a liquid medium, wherein the pigment dispersant (A) is a polymer having a structural unit containing an oxazolidinyl group. Regarding pigment dispersions.

The present invention also relates to an ink composition containing the pigment dispersion.

The present invention further relates to the ink composition containing the compound (B) containing an isocyanate group.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a pigment dispersion having excellent dispersibility and an ink composition having excellent chemical resistance and heat resistance.

Hereinafter, the present invention will be described in detail. In the present specification, (meth) acrylate means acrylate and / or methacrylate, and (meth) acrylic acid means acrylic acid and / or methacrylic acid.

<< Pigment dispersion >>
<Pigment Dispersant (A)>
The pigment dispersant (A) of the present invention is characterized by being a polymer having a structural unit containing an oxazolidine group (a group obtained by removing one hydrogen atom from oxazolidine). Preferably, it is a vinyl resin type dispersant obtained by radically polymerizing a monomer (a) containing a monomer (a-1) containing an oxazolidinyl group. The pigment dispersant (A) is excellent in pigment dispersibility because the oxazolidinyl group (or the alkanolamino group described later) functions as an adsorption site for the pigment.

In addition, the oxazolidinyl group itself does not have active hydrogen and has no crosslinkability, but it is hydrolyzed by contact with water and changed to an alkanolamino group. This alkanolamino group serves as a cross-linking group, which can increase the cross-linking density and improve various resistances. Examples of the cross-linking reaction include a Michael addition reaction with a photopolymerizable functional group such as a (meth) acryloyl group, a urethanization reaction with an isocyanate group, or a urea conversion reaction.

Water for hydrolyzing the oxazolidinyl group may be added when the pigment dispersion is prepared, or may be added when the ink composition is prepared from the pigment dispersion. Further, the moisture contained in the hydrophilic material added to the ink composition or the moisture in the air may be used. The crosslinkable compound that reacts with the alkanolamino group may be added when the pigment dispersion is prepared, or may be added when the ink composition is prepared.

The pigment dispersant (A) is a method of polymerizing a monomer (a) containing a monomer (a-1) containing an oxazolidinyl group, or a polymer obtained by polymerizing the monomer (a) (a polymer (a). It can be obtained by a method of introducing an oxazolidinyl group into a prepolymer), but is not particularly limited.
The method of polymerizing the monomer (a) containing the monomer (a-1) containing an oxazolidinyl group is preferable in that the reaction process of synthesis can be reduced. Further, the pigment dispersant (A) may be a homopolymer or a copolymer with another monomer, but the Tg of the polymer, the viscosity of the pigment dispersion, compatibility with other constituents, etc. A copolymer with another monomer is preferable for the purpose of adjusting the above.

[Monomer (a)]
Examples of the monomer (a-1) containing an oxazolidinyl group include a monomer represented by the following general formula [1].

［式中Ｒ^１およびＲ^２は、それぞれ独立に、水素原子、炭素数１から１２の、直鎖状もしくは分岐状の脂肪族炭化水素基、脂環族炭化水素基または芳香族炭化水素基から選ばれる１価の基、またはＲ^１およびＲ^２が結合した、炭素数３から１２の直鎖状もしくは分岐状の脂肪族炭化水素基、脂環族炭化水素基または芳香族炭化水素基から選ばれる２価の基である。Ｒ^３は炭素原子、水素原子、酸素原子、窒素原子、硫黄原子から構成される２価の基であり、Ｒ^４は酸素原子または−ＮＨ−であり、Ｒ^５は水素原子またはメチル基である。］ General formula [1]

[In the formula, R ¹ and R ² are independently derived from a hydrogen atom, a linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group or an aromatic hydrocarbon group, respectively. Select from a monovalent group of choice, or a linear or branched aliphatic hydrocarbon group with 3 to 12 carbon atoms, an alicyclic hydrocarbon group or an aromatic hydrocarbon group to which ^{R 1} and R ^{2 are bonded.} It is a divalent group. R ³ is a divalent group composed of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom and a sulfur atom, R ⁴ is an oxygen atom or -NH-, and R ⁵ is a hydrogen atom or a methyl group. .. ]

From the viewpoint of the reactivity of the oxazolidinyl group, it is preferable that R ¹ and R ² are combined to form an aliphatic hydrocarbon group having 4 or 5 carbon atoms. From the viewpoint of ease of production, R ³ is preferably an ethylene group and R ⁴ is preferably an oxygen atom.

The method for introducing an oxazolidine group into the prepolymer is not particularly limited, but a method of reacting the prepolymer with an oxazolidine compound having a reactive functional group is preferable. For example, it is obtained by reacting a prepolymer having a carboxyl group, a carboxylic acid ester group, a carboxylic acid anhydride group, or an isocyanate group with an oxazolidine compound having a hydroxyl group, and an oxazolidine compound having a carboxyl group on the prepolymer having an epoxy group. Can also be obtained by reacting.

Examples of the monomer containing a carboxyl group include (meth) acrylic acid, acrylic acid dimer, itaconic acid, maleic acid, fumaric acid, crotonic acid, α- (hydroxymethyl) (meth) acrylic acid, and 2- (meth) acrylic acid. Loyloxyethyl phthalate, 2- (meth) acrylicyloxypropylphthalate, 2- (meth) acrylicyloxyethyl hexahydrophthalate, 2- (meth) acrylicyloxypropylhexahydrophthalate, β-carboxyethyl (meth) acrylate , Ethylene oxide-modified succinic acid (meth) acrylate, ω-carboxypolycaprolactone (meth) acrylate, p-vinylbenzoic acid, and a monomer obtained by adding and reacting a carboxylic acid anhydride with a monomer containing a hydroxyl group, etc. Can be mentioned.

Examples of the monomer containing a carboxylic acid ester group include a compound obtained by esterifying the carboxyl group of the monomer containing a carboxyl group with a monofunctional alcohol.

Examples of the monomer containing a carboxylic acid anhydride group include maleic anhydride, itaconic anhydride, 4-[(2-methacryloyloxyethoxy) carbonyl] phthalic anhydride and the like.

Examples of the monomer containing an isocyanate group and its block body include (meth) acryloyl isocyanate, 2-isocyanatoethyl (meth) acrylate, 2- (meth) acryloyloxyethoxyethyl isocyanate, and 1,1- (bis (meth)). Examples thereof include acryloyloxymethyl) ethyl isocyanate, m- (meth) acryloylphenyl isocyanate, α, α-dimethyl-4-isopropenylbenzyl isocyanate and the like.

Examples of the monomer containing an epoxy group include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether, 3,4-epoxide butyl (meth) acrylate, and 3-methyl-3. , 4-Epoxide butyl (meth) acrylate, 3-Ethyl-3,4-Epoxide butyl (meth) acrylate, 4-Methyl-4,5-Epoxide pentyl (meth) acrylate, 5-Methyl-5,6-Epoxide hexyl (Meta) acrylate, glycidyl α-ethylacrylate, allyl glycidyl ether, crotonyl glycidyl ether, glycidyl ether (iso) crotonate, (3,4-epoxide cyclohexyl) methyl (meth) acrylate, N- (3,5-) Dimethyl-4-glycidyl) benzylacrylamide, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, α-methyl-o-vinylbenzyl glycidyl ether, α-methyl-m-vinylbenzyl glycidyl Ether, α-methyl-p-vinylbenzyl glycidyl ether, 2,3-diglycidyloxymethylstyrene, 2,4-diglycidyloxymethylstyrene, 2,5-diglycidyloxymethylstyrene, 2,6-diglycidyloxy Methylstyrene, 2,3,4-triglycidyloxymethylstyrene, 2,3,5-triglycidyloxymethylstyrene, 2,3,6-triglycidyloxymethylstyrene, 3,4,5-triglycidyloxymethylstyrene , 2,4,6-triglycidyloxymethylstyrene and the like.

Examples of the oxazolidine compound containing a hydroxyl group include 3- (2-hydroxyethyl) -2,2-spirocyclohexyl-1,3-oxazolidine. Examples of the oxazolidine compound containing a carboxyl group include 3- (2-carboxyethyl) -2,2-spirocyclohexyl-1,3-oxazolidine. These may use one kind of compound or may use two or more kinds of compounds in combination.

The concentration of the oxazolidinyl group in the pigment dispersant (A) is preferably 0.2 to 4.0 mmol per 1 g of the polymer. When the concentration of the oxazolidinyl group is 0.2 mmol or more, the chemical resistance of the ink composition is excellent, and when it is 4.0 mmol or less, the stability of the dispersant (A) with time is excellent. The concentration of oxazolidinyl groups is calculated from the formula defined below.
Concentration of oxazolidinyl groups per 1 g of polymer [mmol] = number of moles of oxazolidinyl groups in 1 g of polymer [mol] x number of oxazolidinyl groups in structural units containing oxazolidinyl groups x 1000
More specific formulas are given below as examples for each method of producing the pigment dispersant (A).
(1) When the monomer (a) containing the monomer (a-1) containing an oxazolidinyl group is polymerized Wt (a-1) ÷ (Wt (a) × MW (a-1) × f (a) -1))) x 1000
Here, Wt (a-1) is the charged mass [g] of the monomer (a-1).
Wt (a) is the total mass [g] of the monomer (a) charged.
MW (a-1) is the formula amount [g / mol] of the monomer (a-1).
f (a-1) represents the number of oxazolidinyl groups contained in one molecule of the monomer (a-1).
(2) When the monomer (a) is polymerized and the obtained polymer (prepolymer) is reacted with an oxazolidine compound having a reactive functional group Wt (a-1') ÷ ((Wt (a')) -Wt (leav)) x MW (a-1') x f (a-1')) x 1000
Here, Wt (a-1') is the charged mass [g] of the oxazolidine compound having a reactive functional group.
Wt (a') is the total mass [g] of the monomer (a) and the oxazolidine compound having a reactive functional group.
Wt (leav) is the mass of the elimination compound [g]
MW (a-1') is the formula amount [g / mol] of an oxazolidine compound having a reactive functional group.
f (a-1') represents the number of oxazolidinyl groups contained in one molecule of the oxazolidine compound having a reactive functional group.
The desorbed compound is a desorbed compound generated when the reaction between the prepolymer and the oxazolidine compound having a reactive functional group is a condensation reaction. For example, a prepolymer having a carboxylic acid ester group has a hydroxyl group. Refers to an alcohol generated when an ester exchange reaction is carried out with an oxazolidine compound having.
A condensation reaction occurs when a prepolymer having a carboxyl group, a carboxylic acid anhydride group, or an isocyanate group is reacted with an oxazolidine compound having a hydroxyl group, or when a prepolymer having an epoxy group is reacted with an oxazolidine compound having a carboxyl group. Therefore, Wt (leav) is 0 g.

The pigment dispersant (A) containing an oxazolidinyl group may contain a photopolymerizable functional group. By including a photopolymerizable functional group, it may be possible to improve various resistances of the ink composition. The photopolymerizable functional group is preferably a (meth) acryloyl group.
The method for introducing the photopolymerizable functional group into the pigment dispersant (A) is not particularly limited, but the alkanolamino group generated by contacting the oxazolidinyl group contained in the pigment dispersant (A) with water and hydrolyzing it. There is a method of reacting a monomer having an isocyanate group or an epoxy group with, or a method of reacting a monomer having an isocyanate group or an epoxy group with a carboxyl group or a hydroxyl group copolymerized with the pigment dispersant (A). Be done. The radically polymerizable double bond in the monomer functions as a photopolymerizable functional group.

Other monomers that can be used as the monomer (a) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl (n-butyl). Meta) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2,2,4-trimethylcyclohexyl (meth) acrylate, 4-t-butyl Cyclohexyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, tricyclo -[5.2.1.0 (2,6)]-decanyl (meth) acrylate, tricyclo- [5.2.1.0 (2,6)]-fat such as decanyloxyethyl (meth) acrylate Group monomer;
Aromatic monomers such as phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, and rosin acrylate;
Oxetane (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, (2-ethyl-2-methyl-1,3-dioxolan-4-yl) methyl (meth) acrylate, 1,4-dioxaspiro [4,5] deca -2-yl) Methyl (meth) acrylate, 2-methacryloyloxy-γ-butyrolactone, 3-methacryloyloxy-γ-butyrolactone, 5-methacryloyloxy-2,6-norbornancarbolactone, β-methacryloyloxy-β-methyl Includes heterocycles such as −δ-valerolactone, β-methacryloyloxy-β-methyl-γ-butyrolactone, 2- (1-methacryloyloxy) ethyl-4-butanolide, N- (meth) acryloyloxyethyl hexahydrophthalimide, etc. Monomer;
Hydroxyalkyl (such as 2-hydroxyethyl (meth) acrylate, 2 (or 3) -hydroxypropyl (meth) acrylate, 2 (or 3 or 4) -hydroxybutyl (meth) acrylate and cyclohexanedimethanol mono (meth) acrylate. Meta) acrylates and (meth) acrylates having hydroxyl groups such as alkyl-α-hydroxyalkyl acrylates such as ethyl-α-hydroxymethyl acrylate;
N- (hydroxyalkyl) (meth) acrylamide such as N- (2-hydroxyethyl) (meth) acrylamide, N- (2-hydroxypropyl) (meth) acrylamide, N- (2-hydroxybutyl) (meth) acrylamide (Meta) acrylamides having hydroxyl groups such as;
Vinyl ethers having hydroxyl groups such as 2-hydroxyethyl vinyl ether, 2- (or 3-) hydroxypropyl vinyl ether, 2- (or 3- or 4-) hydroxybutyl vinyl ether;
Allyl ethers having hydroxyl groups such as 2-hydroxyethyl allyl ether, 2- (or 3-) hydroxypropyl allyl ether, 2- (or 3- or 4-) hydroxybutyl allyl ether;
N, N-Dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, 1- (t-butylamino) ethyl (meth) acrylate, 2- (t-butylamino) ethyl (meth) acrylate , 2,2,6,6-tetramethylpiperidin-4-yl (meth) acrylate, N- (2,2,6,6-tetramethylpiperidinyl) (meth) acrylamide, etc. body;
Polyalkylene glycols such as polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) acrylate, and ethoxypolypropylene glycol (meth) acrylate. Monomer containing;
(Meta) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, isobutyl (meth) acrylamide, t-butyl Unsubstituted or N-substituted (meth) acrylamides such as (meth) acrylamide, t-octyl (meth) acrylamide, 2-hydroxyethyl acrylamide, diacetone (meth) acrylamide, and acryloylmorpholin;
Nitriles such as (meth) acrylonitrile;
Polymerizable oligomers such as one-ended methacryloylated polymethylmethacrylate oligomers, one-ended methacryloylated polystyrene oligomers, and one-ended methacryloylated polyethylene glycol;
Styrenes such as styrene, α-methylstyrene, p-hydroxystyrene, chloromethylstyrene, vinyltoluene, inden;
Vinyl ethers such as ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether and isobutyl vinyl ether;
Fatty acid vinyls such as vinyl acetate and vinyl propionate;
N-substituted maleimides such as N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide;
And so on.

The weight average molecular weight (Mw) of the pigment dispersant (A) is preferably 2000 to 70000, more preferably 4000 to 50000. This is because when the weight average molecular weight is 2000 or more, the chemical resistance of the ink composition is excellent, and when the weight average molecular weight is 70,000 or less, the ink composition tends to have a low viscosity and coating is easy.
The weight average molecular weight in this embodiment is a value obtained by gel permeation chromatography (GPC) and converted into polystyrene. More specifically, the values obtained by the measurement method described in Examples described later are shown.

<Compound (B) containing an isocyanate group>
The compound (B) containing an isocyanate group is used to improve the chemical resistance of the cured product by subjecting it to a urethanization reaction or a urea conversion reaction with an alkanolamine produced by hydrolysis of a pigment dispersant (A) containing an oxazolidinyl group. Is preferable. The compound (B) may be contained in the pigment dispersion or may be contained in the ink composition. Further, the compound (B) may be a blocked isocyanate group blocked with a blocking agent according to the subsequent step.
Examples of the compound containing a blocked isocyanate group include compounds in which a compound having an isocyanate group is blocked with a compound having a blocking group (blocking agent) such as lactam, oxime, alcohol, amine, active methylene or phenol. Can be mentioned.

When an alkanolamino group and an isocyanate group are reacted in a pigment miniaturization or dispersion step and crosslinked on the pigment surface to obtain a treated pigment, the compound (B) containing an isocyanate group is used in order to appropriately react at a low processing temperature. It is preferable to use one that is not blocked, or one that is blocked with an amine-based or active methylene-based blocking agent that deblocks at low temperature.
When the ink composition is coated, dried, and baked, the alkanolamino group and the isocyanate group are reacted to crosslink the coated product, and a blocked isocyanate group is used to impart stability to the ink composition. It is preferable to use the compound (B) having. At this time, it is preferable to use an appropriate blocking agent according to the process temperature of drying and baking. For example, when the process temperature is 100 ° C. or lower, amine-based or active methylene-based compounds are preferable, and when the process temperature is 100 ° C. or higher, a compound blocked with a compound having a blocking group such as lactam-based, oxime-based, alcohol-based, or phenol-based is used. Is preferable.

Examples of the compound having an isocyanate group include methyl isocyanate, butyl isocyanate, hexyl isocyanate, heptyl isocyanate, lauryl isocyanate, stearyl isocyanate, phenyl isocyanate, cyclopropyl isocyanate, phenethyl isocyanate, tosyl isocyanate, acryloyloxyethyl isocyanate and methacryloyloxyethyl isocyanate. Vinyl isocyanate, allyl isocyanate, 2- (2-acryloyloxyethyloxy) ethyl isocyanate, 2- (2-methacryloyloxyethyloxy) ethyl isocyanate, 1,1-bis (acryloyloxymethyl) ethyl isocyanate, 1,1-bis Monofunctional isocyanates such as (methacryloyloxymethyl) ethyl isocyanate;
Tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, phenylenedi isocyanate, trizine isocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane diisocyanate, isopropyridenebis Bifunctional isocyanates such as (cyclohexylisocyanate), 3- (2'-isocyanatocyclohexyl) propyl isocyanate, dianisidine isocyanate, diphenyl ether diisocyanate, dimerged isocyanate, tetramethylxylylene diisocyanate;
Trifunctional isocyanates such as lysine triisocyanate, tris (isocyanatophenyl) methane, tris (isocyanatophenyl) thiophosphate;
Examples thereof include the above-mentioned polyfunctional isocyanate biuret, uretdione, isocyanurate, adduct, and the above-mentioned monomer polymer containing an isocyanate group.

<Pigment>
The pigment is not particularly limited, but is preferably an organic or inorganic pigment, and can be used alone or in combination of two or more. Among the pigments, pigments having high color development and high heat resistance are preferable, and organic pigments are usually used, but the pigments are not limited thereto. The pigment may have an acidic or basic surface, but is preferably an acidic pigment.

The organic pigments that can be used in the present invention are not particularly limited, and for example, soluble azo pigments, insoluble azo pigments, phthalocyanine pigments, halogenated phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, isoindolin pigments, perylene pigments, etc. There are perinone pigments, dioxazine pigments, anthraquinone pigments, dianthraquinonyl pigments, anthrapyrimidine pigments, anthanthrone pigments, indanslon pigments, flavanthron pigments, pyranthron pigments, diketopyrrolopyrrole pigments and the like, and more specific examples thereof. Is indicated by the generic name of the color index: Pigment Black 7, Pigment Blue 15, Pigment Blue 15: 1, Pigment Blue 15: 3, Pigment Blue 15: 4, Pigment Blue 15: 6, Pigment Blue 22, Pigment Blue 60, Or a blue pigment such as Pigment Blue 64;
Green pigments such as Pigment Green 7, Pigment Green 36, or Pigment Green 58;
Pigment Red 9, Pigment Red 48, Pigment Red 49, Pigment Red 52, Pigment Red 53, Pigment Red 57, Pigment Red 97, Pigment Red 122, Pigment Red 123, Pigment Red 144, Pigment Red 146, Pigment Red 149, Pigment Red 166, Pigment Red 168, Pigment Red 177, Pigment Red 178, Pigment Red 179, Pigment Red 180, Pigment Red 185, Pigment Red 192, Pigment Red 202, Pigment Red 206, Pigment Red 207, Pigment Red 209, Pigment Red 215, Pigment Red 216, Pigment Red 217, Pigment Red 220, Pigment Red 221 Red pigments such as 254 or Pigment Red 255;
Purple pigments such as Pigment Violet 19, Pigment Violet 23, Pigment Violet 29, Pigment Violet 30, Pigment Violet 37, Pigment Violet 40, or Pigment Violet 50;
Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 17, Pigment Yellow 20, Pigment Yellow 24, Pigment Yellow 74, Pigment Yellow 83, Pigment Yellow 86, Pigment Yellow 93, Pigment Yellow 94, Pigment Yellow 95, Pigment Yellow 109, Pigment Yellow 110, Pigment Yellow 117, Pigment Yellow 120, Pigment Yellow 125, Pigment Yellow 128, Pigment Yellow 137, Pigment, Yellow 138, Pigment Yellow 139, Pigment Yellow 147, Pigment Yellow 148, Pigment Yellow 150, Pigment Yellow 151 , Pigment Yellow 153, Pigment Y | · _t = Yellow 154, Pigment Yellow 155, Pigment Yellow 166, Pigment Yellow 168, Pigment Yellow 180, Pigment Yellow 185, or Pigment Yellow 213.
Pigment Orange 13, Pigment Orange 36, Pigment Orange 37, Pigment Orange 38, Pigment Orange 43, Pigment Orange 51, Pigment Orange 55, Pigment Orange 59, Pigment Orange 61, Pigment Orange 64, Pigment Orange 71, or Pigment Orange 74, etc. Orange pigments; or brown pigments such as Pigment Brown 23, Pigment Brown 25, or Pigment Brown 26.

Inorganic pigments include barium sulfate, zinc white, lead sulfate, yellow lead, zinc yellow, red iron oxide (III), cadmium red, ultramarine blue, dark blue, chromium oxide green, cobalt green, amber, and titanium black. , Synthetic iron black, metal oxide powders such as titanium oxide and iron tetroxide, metal sulfide powders, metal powders and the like, and all carbon blacks such as neutral, acidic or basic. Inorganic pigments are preferably used in combination with organic pigments in order to ensure good coatability, sensitivity, developability, etc. while balancing saturation and lightness. Further, since the color is adjusted, the dye can be contained within a range that does not reduce the heat resistance.

The amount of the pigment added is preferably in the range of 10 to 55% by weight in the solid content of the ink composition in order to secure a sufficient color gamut of the printed matter.

<Pigment miniaturization>
When a pigment is used in the present invention, it is preferable to use it in a finely divided manner, but the finening method is not particularly limited, and for example, wet grinding, dry grinding, dissolution precipitation method and the like can be used, and Japanese Patent Application Laid-Open No. 2014 The solvent salt milling treatment by the kneader method, which is one of the wet grinding methods described in −208758, can be performed. The average primary particle size of the pigment is preferably 20 nm or more because the dispersion in the pigment carrier is good. The average primary particle size of the pigment in the present embodiment refers to a method of directly measuring the size of the primary particle from an electron micrograph of the pigment by a TEM (transmission electron microscope). Specifically, the minor axis diameter and the major axis diameter of the primary particles of each pigment were measured, and the average was taken as the particle size of the pigment particles. Next, for 100 or more pigment particles, the volume of each particle was obtained by approximating it to a cube having a obtained particle size, and the volume average particle size was defined as the average primary particle size.

Solvent salt milling treatment is a process of heating a mixture of a pigment, a water-soluble inorganic salt, and a water-soluble organic solvent using a kneader such as a kneader, a 2-roll mill, a 3-roll mill, a ball mill, an attritor, or a sand mill. After mechanically kneading, the water-soluble inorganic salt and the water-soluble organic solvent are removed by washing with water. The water-soluble inorganic salt acts as a crushing aid, and the pigment is crushed by utilizing the high hardness of the inorganic salt during salt milling. By optimizing the conditions for the salt milling treatment of the pigment, it is possible to obtain a pigment having a very fine primary particle size, a narrow distribution width, and a sharp particle size distribution.

As the water-soluble inorganic salt, sodium chloride, barium chloride, potassium chloride, sodium sulfate and the like can be used, but sodium chloride (salt) is preferably used from the viewpoint of price. From the viewpoint of both treatment efficiency and production efficiency, the water-soluble inorganic salt is preferably used in an amount of 50 to 2000 parts by weight, most preferably 300 to 1000 parts by weight, based on 100 parts by weight of the pigment.

The water-soluble organic solvent has a function of wetting the pigment and the water-soluble inorganic salt, and is not particularly limited as long as it dissolves (mixes) in water and does not substantially dissolve the inorganic salt used. However, since the temperature rises during salt milling and the solvent easily evaporates, a high boiling point solvent having a boiling point of 120 ° C. or higher is preferable from the viewpoint of safety. For example, 2-methoxyethanol, 2-butoxyethanol, 2- (isopentyloxy) ethanol, 2- (hexyloxy) ethanol, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, Liquid polyethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, liquid polypropylene glycol and the like are used. The water-soluble organic solvent is preferably used in an amount of 5 to 1000 parts by weight, most preferably 50 to 500 parts by weight, based on 100 parts by weight of the pigment.

When the pigment is subjected to salt milling treatment, a resin may be added if necessary. The type of resin used is not particularly limited, and a natural resin, a modified natural resin, a synthetic resin, a synthetic resin modified with a natural resin, or the like can be used. Further, a dispersant (A) containing an oxazolidinyl group may be used. The resin used is preferably solid at room temperature, water-insoluble, and more preferably partially soluble in the organic solvent. The amount of the resin used is preferably in the range of 5 to 200 parts by weight with respect to 100 parts by weight of the pigment.

<< Ink composition >>
The pigment dispersant (A) of the present invention can be used for various inkjet inks such as organic solvent-based, water-based, and active energy ray-curable inks, resist inks, offset inks, gravure inks, flexographic inks, and the like. Further, by adding a compound containing a photopolymerizable functional group and a photopolymerization initiator to the ink composition, it can be suitably used for UV inks and resist inks having excellent chemical resistance and abrasion resistance of the coating film. .. The alkanolamine produced by hydrolysis of the pigment dispersant (A) containing an oxazolidinyl group increases the crosslink density of the ink composition by carrying out a Michael addition reaction with the added compound containing a photopolymerizable functional group to crosslink. , Various resistances can be improved.

<Compounds containing photopolymerizable functional groups>
The compound containing a photopolymerizable functional group added in the present embodiment does not contain an oxazolidinyl group, and its structure is not particularly limited as long as it contains a photopolymerizable functional group, and it may be used alone or in combination of two or more. Can be used. It may be a small molecule or a polymer, and the ratio can be adjusted by using a small molecule and a polymer properly or by using them in combination.
Examples of the photopolymerizable functional group include an acryloyl group, a methacryloyl group, a maleimide group, a styryl group, a maleic anhydride residue, a vinyl ether group, an allyl ether group, an alkenyl group having 2 to 10 carbon atoms, and an alkynyl group having 2 to 10 carbon atoms. And so on. It is preferable to use an acryloyl group from the viewpoint of improving various resistances of the ink composition. As the photopolymerizable functional group, different functional groups such as acryloyl group and methacryloyl group may be contained in one compound, or compounds having one kind of functional group may be mixed and used.
The compound containing a photopolymerizable functional group is preferably used in an amount of 5 to 95 parts by mass, more preferably 10 to 80 parts by mass, and 15 to 70 parts by mass based on 100 parts by mass of the total solid content of the ink composition. Is even more preferable. It is preferable to use 5 parts by mass or more because chemical resistance can be easily obtained, and 95 parts by mass or less is preferable because curing shrinkage during exposure is suppressed and adhesion to the substrate tends to be good.
Among the compounds containing photopolymerizable functional groups, low molecular weight compounds include monofunctional or polyfunctional monomers or oligomers. Examples of the compound containing a (meth) acryloyl group, which is preferable as a photopolymerizable functional group, include oxazolidinyl among those exemplified as the monomer (a) used in synthesizing the pigment dispersion (A) containing the oxazolidinyl group. Examples thereof include (meth) acryloyl monomer excluding the monomer (a-1) containing a group.
Further, for example, ethylene glycol di (meth) acrylate, EO-modified bisphenol A di (meth) acrylate, 1,4-butanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth). ) Bifunctional (meth) acrylates such as acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate;
Trifunctional (meth) acrylates such as trimethylolpropane tri (meth) acrylate and pentaerythritol tri (meth) acrylate;
Pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tripentaerythritol octa (meth) acrylate, tetrapentaerythritol deca (meth) acrylate, pentapentaerythritol dodeca (meth) ) Four-functional or higher (meth) acrylates such as acrylate;
Polyfunctional (meth) acrylates obtained by reacting a polyfunctional isocyanate with a (meth) acrylate monomer containing a hydroxyl group;
Epoxy (meth) acrylates obtained by reacting an epoxy resin with a (meth) acrylate monomer containing a carboxyl group, or reacting a phenol resin with a (meth) acrylate monomer containing an epoxy group, etc. Can be mentioned.

A polymer may be used as the compound containing a photopolymerizable functional group. For example, poly (meth) acrylate, polyurethane, polyester, polyamide, polyimide, polycarbonate, polyolefin, polystyrene, polysiloxane, polyether, copolymer containing maleic anhydride, epoxy resin, etc. with a photopolymerizable functional group introduced. Etc. can be used, and these may be used alone or as a mixture. The polymer may be linear, branched, stellate or the like, and may be thermoplastic or thermosetting.

When the compound containing a photopolymerizable functional group has a high molecular weight, the weight average molecular weight (Mw) is preferably 2000 to 50,000, more preferably 4000 to 30000. This is because when Mw is 2000 or more, the chemical resistance of the ink composition tends to be good, and when it is 50,000 or less, the viscosity becomes low and coating becomes easy.

<Photopolymerization initiator>
The structure of the photopolymerization initiator is not particularly limited as long as it is used for initiating the polymerization of the photopolymerizable functional group in the photosensitive composition by generating radicals by irradiation with ultraviolet rays. for example,
4-Phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, p-dimethylaminoacetophenone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxy Cyclohexylphenylketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane- 1-one, 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, JP-A-54-99185, JP-A. 63-264560, acetophenone compounds such as the compounds described in JP-A-10-299777, benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl dimethyl ketal, benzophenone, benzoyl benzoic acid, benzoyl benzoate Methyl acid, 4-phenylbenzophenone, hydroxybenzophenone, acrylicized benzophenone, 4-benzoyl-4'-methyldiphenylsulfide, 3,3', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone and other benzophenones Compounds, thioxanthone compounds such as thioxanthone, 2-chlorthioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-diethylthioxanthone, 2,4,6-trichloro-s-triazine, 2- Phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-tolyl) -4,6 -Bis (trichloromethyl) -s-triazine, 2-piperonyl-4,6-bis (trichloromethyl) -s-triazine, 2,4-bis (trichloromethyl) -6-styryl-s-triazine, 2-( Naft-1-yl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxy-naphth-1-yl) -4,6-bis (trichloromethyl) -s-triazine, 2 , 4-Trichloromethyl- (piperonyl) -6-triazine, 2,4-trichloromethyl (4'-methoxystyryl) -6-triazine, Tokusho 59-1281, Tokukousho 61-9621, triazine compounds such as the compounds described in JP-A-60-60104, 1,2-octanedione, 1- [4- (phenylthio) phenyl-, 2- (O-benzoyloxime)], JP-A. 2001-264530, JP-A-2001-261716, JP-A-2000-80068, JP-A-2001-233842, JP-A-2004-534977, JP-A-2006-342166, JP-A-2008-09470, JP-A-2009-40762, JP-A-2010- 15025, Japanese Patent Application Laid-Open No. 2010-189279, Japanese Patent Application Laid-Open No. 2010-189280, Japanese Patent Application Laid-Open No. 2010-526846, Japanese Patent Application Laid-Open No. 2010-527338, Japanese Patent Application Laid-Open No. 2010-527339, USP3558309 (1971), USP4202697 (1980), Oxyme ester compounds such as those described in JP-A-61-24558, JP-A-2012-516191, JP-A-2012-526185, JP-A-2013-543875, JP-A-2011-209710, bis (2,4,6-trimethyl). Bencoyl) phenylphosphine oxide, phosphine compounds such as 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2,2'-bis (o-chlorophenyl) -4,5,4', 5'-tetraphenyl- 1,2'-biimidazole, 2,2'-bis (o-methoxyphenyl) -4,4', 5,5'-tetraphenyl biimidazole, 2,2'-bis (o-chlorophenyl) -4, 4', 5,5'-tetra (p-methylphenyl) biimidazole, imidazole compounds such as the compounds described in JP-A-55-127550, JP-A-60-202437, 9,10-phenanthrene quinone, Kinone-based compounds such as camphorquinone and ethylanthraquinone, borate-based compounds such as the compounds described in JP-A-2-157760, carbazole-based compounds, titanosen-based compounds such as the compounds described in JP-A-61-151197, JP-A-59-1504 No., Organic peroxides such as compounds described in JP-A-61-243807, Diazoniums such as compounds described in JP-A-43-23684, JP-A-44-6413, JP-A-47-1604, USP No. 3567453 Compounds, organic azide compounds such as the compounds described in USP No. 2848328, USP No. 2852379, USP No. 2940853, Tokusho 36-22062, Tokukou 37-13109, Tokukou 38- 18015, ortho-quinone diazides such as compounds described in JP-A-45-9610, JP-A-55-39162, JP-A-59-140203, "MACROMOLECULES", Vol. 10, p. 1307 (1977). Year), various onium compounds including iodonium compounds, azo compounds such as compounds described in JP-A-59-142205, JP-A-1-54440, European Patent No. 109851, European Patent No. 126712. No., "Journal of Imaging Science (J. IMAG. SCI. ) ”, Vol. 30, pp. 174 (1986), metal allen complexes such as compounds,“ Coordination Chemistry Review ”, Vol. 84, pp. 85-277 (1988). ), Transition metal complexes containing transition metals such as ruthenium described in JP-A-2-182701, aluminate complexes such as compounds described in JP-A-3-209477, carbon tetrabromide and JP-A-59-107344. Examples thereof include organic halogen compounds such as the above compounds, sulfonium complexes and oxosulfonium complexes described in JP-A-5-255347.

These photopolymerization initiators can be used alone or in admixture of two or more at any ratio, if necessary. The photopolymerization initiator is preferably 0.01 to 60 parts by mass, more preferably 0.01 to 10 parts by mass, still more preferably 0.03 to 7 parts by mass in 100 parts by mass of the solid content in the photosensitive composition. It is a department. It is preferably 0.01 part by mass or more from the viewpoint of photopolymerizability, that is, the progress of the polymerization reaction, and 10 parts by mass or less from the viewpoint of suppressing a decrease in transparency due to the influence of yellowing of the initiator. preferable.

<Other heat-crosslinkable resins>
In addition to the above-mentioned compound containing a photopolymerizable functional group, a heat-crosslinkable compound containing a functional group that reacts with an amino group and a hydroxyl group in an alkanolamine produced by hydrolysis of a pigment dispersant (A) containing an oxazolidinyl group. May increase the crosslink density of the ink composition and improve various resistances. Examples of the heat-crosslinkable compound include a compound containing an epoxy group, a compound containing a methylol group, a compound containing an active methylene group or an active methine group, and a compound containing a carbonyl group.

Examples of the epoxy-containing compound include aliphatic alcohol glycidyl ethers such as 1,6-hexanediol diglycidyl ether and neopentyl glycol diglycidyl ether, bisphenol A type epoxy resin, phenol novolac type epoxy resin, bisphenol F type epoxy resin, and bisphenol. S-type epoxy resin, cresol novolac-type epoxy resin, glycidylamine-type epoxy resin, naphthalene-type epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, polyfunctional epoxy resin, biphenyl-type epoxy resin , Glycidyl ester type epoxy resin, alcohol type epoxy resin such as hydrogenated bisphenol A type epoxy resin, halogenated epoxy resin such as brominated epoxy resin, rubber modified epoxy resin, urethane modified epoxy resin, epoxidized polybutadiene, epoxidized styrene- Examples thereof include a butadiene-styrene block copolymer, an epoxy group-containing polyester resin, an epoxy group-containing polyurethane resin, an epoxy group-containing acrylic resin, and EHPE-3150 (manufactured by Daicel Co., Ltd.). These epoxy resins may be liquid at room temperature or solid. Epoxy group-containing oligomers can also be used, and examples thereof include bisphenol A type epoxy oligomers (for example, manufactured by Oleochemical Shell Epoxy Co., Ltd., Epicoat 1001, 1002, etc.). Further, an addition polymer of the epoxy group-containing monomer or oligomer may be used, and examples thereof include glycidylated polyester, glycidylated polyurethane, and glycidylated acrylic.

Examples of the compound containing a methylol group include a melamine-containing compound in which a plurality of methylol groups, methoxymethyl groups, and butoxymethyl groups are substituted with nitrogen atoms such as hexamethylol melamine, hexamethoxymethyl melamine, and hexabutoxymethyl melamine, and N-methylol acrylamide. , N-alkoxymethylacrylamide and other monomers containing a methylol group and polymers thereof, benzoguanamine resin, urea resin, phenol resin and the like can be mentioned.

Compounds having an active methylene group or an active methine group include 2- (1,3 dioxobutoxy) ethyl (meth) acrylate, 2- (1,3 dioxobutoxy) propyl (meth) acrylate, and (meth). 3- (1,3 dioxobutoxy) propyl acrylate, 2- (1,3 dioxobutoxy) butyl (meth) acrylate, 3- (1,3 dioxobutoxy) butyl (meth) acrylate, (meth) ) A monomer containing an active methylene group such as 4- (1,3 dioxobutoxy) butyl acrylate, or a polymer thereof, acetoacetyl group-modified polyvinyl alcohol (Gosenex Z series manufactured by Nippon Synthetic Chemical Co., Ltd.) and the like can be mentioned. ..

Examples of the compound containing a carbonyl group include diacetone (meth) acrylamide and a polymer thereof.

<Other materials>
In the ink composition of the present embodiment, the following materials can be further added as long as the object of the invention is not impaired.

<Liquid medium>
A liquid medium such as an organic solvent may be used to improve the handling when printing the ink composition. For example, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, tert-butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, benzene, toluene, ethyl benzene. , Xylene, cyclohexane, hexane, octane, dichloromethane, chloroform, dimethylformamide, dimethylacetamide, acetonitrile, dimethylsulfoxide and the like. These organic solvents may be used alone or in admixture of two or more, but are preferably solvents used in the final application.
As the liquid medium, water can be used in the case of a water-based ink, and an active energy ray-curable monomer or the like can be used in the case of an active energy ray-curable ink.

<Surfactant>
Surfactants include polyoxyethylene alkyl ether sulfate, sodium dodecylbenzene sulfonate, alkali salt of styrene-acrylic acid copolymer, sodium alkylnaphthalin sulfonate, sodium alkyldiphenyl ether disulfonate, monoethanolamine lauryl sulfate, and lauryl. Anionic surfactants such as triethanolamine sulfate, ammonium lauryl sulfate, monoethanolamine stearate, sodium stearate, sodium lauryl sulfate;
Nonionic surfactants such as polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene alkyl ether phosphate, polyoxyethylene sorbitan monostearate, polyethylene glycol monolaurate;
Cationic surfactants such as alkyl quaternary ammonium salts and their ethylene oxide adducts;
Examples thereof include alkyl betaines such as alkyl dimethylamino acetate betaine and amphoteric surfactants such as alkyl imidazoline, which can be used alone or in admixture of two or more.

<Pigment derivative>
The pigment derivative is a compound in which a substituent is introduced into an organic pigment, and the organic pigment also includes a pale yellow aromatic polycyclic compound such as a naphthalene type or an anthraquinone type which is not generally called a pigment. Examples of the pigment derivative are described in JP-A-63-305173, JP-A-57-15620, JP-A-59-40172, JP-A-63-17102, JP-B--5946 and the like. These can be used alone or in admixture of two or more.

<Other resins>
The pigment dispersion of the present embodiment may contain other resins not included in any of the above, if necessary. Examples thereof include thermoplastic resins and thermosetting resins.
Examples of the thermoplastic resin include butyral resin, styrene-maleic acid copolymer, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyurethane resin, and polyester resin. , Acrylic resin, alkyd resin, polystyrene, polyamide resin, rubber resin, cyclized rubber resin, celluloses, polyethylene, polybutadiene, polyimide resin and the like.
Examples of the thermosetting resin include rosin-modified maleic acid resin, rosin-modified fumaric acid resin, β-hydroxyalkylamide described in JP-A-2012-198527, and compounds containing a frill group described in JP-A-2017-194662. And so on.

The printing base material is not particularly limited, but plastic base materials such as soft vinyl chloride, hard vinyl chloride, polystyrene, foamed styrol, polymethylmethacrylate (PMMA), polypropylene (PP), polyethylene, polyethylene terephthalate (PET), and polycarbonate, and these. Examples thereof include mixed products or modified products of the above, paper base materials such as high-quality paper, art paper, coated paper and cast-coated paper, and metal base materials such as glass and stainless steel.

Hereinafter, embodiments of the present invention will be described in more detail with reference to Examples, but the following Examples do not limit the scope of rights of the present invention at all. In the examples, "parts" represents "parts by mass" and "%" represents "% by mass".

Further, in the following examples, the molecular weight of the resin is a polystyrene-equivalent weight average molecular weight measured by GPC (gel permeation chromatography). The dispersant (A) containing an oxazolidinyl group was HLC-8320 GPC manufactured by Tosoh Corporation, the eluent used was a solution of 30 mM triethylamine and 10 mM LiBr in N, N-dimethylformamide, and the column was TSKgelSUPER-AW3000 (manufactured by Tosoh Corporation). Was measured at a flow rate of 0.6 ml / min, an injection volume of 10 μl, and a column temperature of 40 ° C. For other polymers, GPC-8020 manufactured by Tosoh Co., Ltd. was used, tetrahydrofuran was used as the eluent, and three TSKgelSuperHM-M (manufactured by Tosoh Co., Ltd.) were used for the column. The measurement was performed at a column temperature of 40 ° C.

IR measurement was performed using a SpectumOne manufactured by PerkinElmer. In the present specification, the non-volatile content means a value calculated from the mass of the sample after heating / the mass of the sample before heating when 1 g of the sample is heated at 200 ° C. for 10 minutes. However, in the case of a commercially available product, a value calculated based on a method specified by the manufacturer may be adopted. In the present specification, solid content and non-volatile content are synonymous.

<< Manufacturing example >>
<Manufacture of Pigment Dispersant (A) Containing Oxazolidinyl Group>
[Manufacturing Example 1]
Put 122.2 parts of propylene glycol monomethyl ether acetate in a reaction vessel equipped with a stirrer, thermometer, dropping device, reflux cooler, and gas introduction tube, and heat to 75 ° C. while injecting nitrogen gas into the vessel to the same temperature. 3- (2-Methyloxyethyl) -2,2-spirocyclohexyl-1,3-oxazolidine 70.0 parts, methyl acrylate 30.0 parts, 2,2'-azobis (2,4-dimethylvaleronitrile) A mixture of 2.7 parts and 97.3 parts of propylene glycol monomethyl ether acetate was added dropwise over 2 hours to carry out a polymerization reaction. After completion of the dropping, the mixture was further reacted at 75 ° C. for 1 hour, and then 0.3 part of 2,2'-azobis (2,4-dimethylvaleronitrile) was dissolved in 10.8 parts of propylene glycol monomethyl ether acetate. The mixture was added, and then stirring was continued at the same temperature for 4 hours to obtain a copolymer. After cooling to room temperature, a pigment dispersant solution (A-1) containing an oxazolidinyl group having a non-volatile content of 30% was obtained. The weight average molecular weight was 9000.

[Manufacturing Examples 2 to 12]
Synthesis was carried out in the same manner as in Production Example 1 except that the raw materials and the charged amounts shown in Table 1 were used to obtain pigment dispersant solutions (A-2 to A-12) having a non-volatile content of 30%. In addition, A-1 to A-8 contain an oxazolidinyl group, and A-9 to A-12 do not contain an oxazolidinyl group.

The abbreviations in Table 1 are shown below.
MA-128: 3- (2-methacryloxyethyl) -2,2-spirocyclohexyl-1,3-oxazolidine DM: N, N-diethylaminoethyl methacrylate FA-711MM: 1,2,2,6,6-pentamethyl -4-Piperidyl Methacrylate HEMA: 2-Hydroxyethyl Methacrylate MA: Methyl Acrylate MMA: Methyl Methacrylate PGM Ac: Propylene Glycol Monomethyl Ether Acetate

<Production of compound (F) containing a photopolymerizable functional group>
[Manufacturing Example 13]
Put 100.0 parts of propylene glycol monomethyl ether acetate in a reaction vessel equipped with a stirrer, thermometer, dropping device, reflux condenser, and gas introduction tube, and heat to 75 ° C. while injecting nitrogen gas into the vessel to the same temperature. 4-Hydroxyphenyl methacrylate 48.7 parts, 2-hydroxyethyl methacrylate 45.3 parts, methyl methacrylate 6.0 parts, 2,2'-azobis (2,4-dimethylvaleronitrile) 2.5 parts, propylene glycol A mixture of 40.0 parts of monomethyl ether acetate was added dropwise over 2 hours to carry out a polymerization reaction. After completion of the dropping, the mixture was further reacted at 75 ° C. for 1 hour, and then 0.5 part of 2,2'-azobisisobutyronitrile dissolved in 10.0 parts of propylene glycol monomethyl ether acetate was added, and then the mixture was added. Stirring was continued at the same temperature for 3 hours to obtain a copolymer. Subsequently, dry air was injected into the reaction vessel, and 39.3 parts of 2-acryloyloxyethyl isocyanate, 0.35 part of dibutyltin dilaurate, 0.35 part of methquinone, and 59.0 parts of propylene glycol monomethyl ether acetate were added, and the temperature was 80 ° C. And stirring was continued for 8 hours to react the hydroxyl group derived from 2-hydroxyethyl methacrylate with the isocyanate group. IR measurement was performed to confirm that the target product was produced. After cooling to room temperature, the mixture was diluted with 116.1 parts of propylene glycol monomethyl ether acetate to obtain a compound solution (F-1) having a non-volatile content of 30% and containing an acryloyl group as a photopolymerizable functional group. The weight average molecular weight was 25,000.

[Manufacturing Example 14]
Put 100.0 parts of propylene glycol monomethyl ether acetate in a reaction vessel equipped with a stirrer, thermometer, dropping device, reflux condenser, and gas introduction tube, and heat to 75 ° C. while injecting nitrogen gas into the vessel to the same temperature. 13.9 parts of methacrylic acid, 45.3 parts of 2-hydroxyethyl methacrylate, 40.8 parts of methyl methacrylate, 2.5 parts of 2,2'-azobis (2,4-dimethylvaleronitrile), propylene glycol monomethyl ether acetate. A polymerization reaction was carried out by dropping 40.0 parts of the mixture over 2 hours. After completion of the dropping, the mixture was further reacted at 75 ° C. for 1 hour, and then 0.5 part of 2,2'-azobisisobutyronitrile dissolved in 10.0 parts of propylene glycol monomethyl ether acetate was added, and then the mixture was added. Stirring was continued at the same temperature for 3 hours to obtain a copolymer. Subsequently, dry air was injected into the reaction vessel, and 39.3 parts of 2-acryloyloxyethyl isocyanate, 0.35 part of dibutyltin dilaurate, 0.35 part of methquinone, and 59.0 parts of propylene glycol monomethyl ether acetate were added, and the temperature was 80 ° C. It was heated to the above, and stirring was continued for 8 hours, and IR measurement was performed to confirm that the target product was produced. After cooling to room temperature, the mixture was diluted with 116.1 parts of propylene glycol monomethyl ether acetate to obtain a compound solution (F-2) having a non-volatile content of 30% and containing an acryloyl group as a photopolymerizable functional group. The weight average molecular weight was 25,000.

<< Pigment dispersion >>
<Manufacturing of pigment dispersion>
[Example 1]
As a pigment, C.I. I. Pigment Green 58 was 12.0 parts, pigment dispersant solution (A-1) was 50.0 parts (solid content 30% by weight), and PGMAc 38.0 parts as a solvent was dispersed by a bead mill to obtain a pigment dispersion (pigment dispersion (solid content 30% by weight)). C-1) was adjusted.

[Example 2]
As a pigment, C.I. I. Pigment Green 58 was 12.0 parts, pigment dispersant solution (A-2) was 44.0 parts (solid content 30% by weight), and as compound (B) containing an isocyanate group, "Death Module" manufactured by Sumika Cobestro Urethane Co., Ltd. 2.77 parts of "BL4265SN" and 41.2 parts of PGMAc as a solvent were dispersed by a bead mill to prepare a pigment dispersion (C-2).

[Example 3]
As a pigment, C.I. I. Pigment Green 58 was 12.0 parts, pigment dispersant solution (A-3) was 38.0 parts (solid content 30% by weight), and as compound (B) containing an isocyanate group, "Death Module" manufactured by Sumika Cobestro Urethane Co., Ltd. 5.54 parts of "BL4265SN" and 44.5 parts of PGMAc as a solvent were dispersed by a bead mill to prepare a pigment dispersion (C-3).

[Examples 4 to 8, Comparative Examples 1 to 4]
Pigments in the same manner as the pigment dispersions (C-1 to C-3) except that the type of pigment dispersant (A) and the amount of compound (B) containing an isocyanate group charged were changed as shown in Table 2. Dispersions (C-4 to C-8) and pigment dispersions for comparison (C-9 to C-12) were prepared.

The abbreviations in Table 2 are shown below.
PGMAc: Propylene glycol monomethyl ether acetate PG58: C.I. I. Pigment Green 58
BL4265SN: Block of IPDI-based polyisocyanate, Solventnaphtha 100 solution with 65% non-volatile content, 8.1% latent NCO group content: Death module BL4265SN (manufactured by Sumika Cobestro Urethane)

<Dispersion stability evaluation of pigment dispersion>
Using the pigment dispersions of Examples 4 to 8 and Comparative Example 3, dispersion stability and heat resistance were evaluated by the following methods. The results are shown in Table 3.

[Evaluation of initial viscosity and viscosity over time]
The viscosity of the obtained pigment dispersion was measured at 23 ° C. using an E-type viscometer (manufactured by Tokyo Keiki) and used as the initial viscosity. The evaluation ranks are as follows.
6.0 mPa · s or more and less than 10.0 mPa · s: Low viscosity and extremely good 10.0 mPa · s or more and less than 14.0 mPa · s: Medium viscosity and good 14.0 mPa · s or more and less than 40.0 mPa · s: High viscosity but within practical range 40.0 mPa · s or more: Not practical In addition, the obtained pigment dispersion is filled in a light-shielding glass container and allowed to stand at 23 ° C. for 1 month in a closed state, and then E-type viscosity. The viscosity was measured again using a meter, and the rate of increase in viscosity after storage for 1 month with respect to the initial viscosity was calculated. The evaluation ranks are as follows.
⊚: Increase rate is less than 5% (extremely good)
◯: Increase rate is 5% or more and less than 7% (good)
Δ: Increase rate is 7% or more and less than 10% (practical)
×: Increase rate is 10% or more (defective)

[Evaluation of heat resistance of coating film]
The obtained pigment dispersion was applied onto a glass substrate having a thickness of 100 mm × 100 mm and a thickness of 1.1 mm using a spin coater, dried at 70 ° C. for 20 minutes, heated at 220 ° C. for 30 minutes, and allowed to cool. A coated substrate was produced. After the heat treatment at 220 ° C., the produced coated film substrate was adjusted to match the chromaticity of y = 0.600 with a C light source.
^{The chromaticity ([L *} ₁ , a ^* ₁ , b ^* ₁ ]) of the obtained coating film at the C light source was measured using a microspectrophotometer (“OSP-SP100” manufactured by Olympus Optical Co., Ltd.). After that, as a heat resistance test, the mixture was heated at 230 ° C. for 1 hour, the chromaticity ([L ^* ₂ , a ^* ₂ , b ^* ₂ ]) with a C light source was measured, and the color difference ΔE ^* was calculated by the following formula. , The evaluation was made in the following four stages.
ΔE ^* = √ ((L ^* _2- L ^* ₁ ) ² + (a ^* _2- a ^* ₁ ) ² + (b ^* _2- b ^* ₁ ) ² )
◯: ΔE ^* is less than 5.0 Δ: ΔE ^* is 5.0 or more

As is clear from the above evaluation results, Examples 1 to 8 using the pigment dispersant solution produced in Production Examples 1 to 8 of the present invention have a low initial viscosity and are good with almost no increase in viscosity with time. It showed dispersion stability. On the other hand, in Comparative Example 3 using the pigment dispersant solution produced in Production Example 11, the dispersibility of the pigment was poor because the pigment dispersion did not have a basic functional group.
In the evaluation of heat resistance, it was found that excellent performance was exhibited in Examples 2, 3, 5 and 6 in which a solution of a pigment dispersant containing an oxazolidinyl group was used and the compound (B) containing an isocyanate group was added. rice field.

<< Resist Ink >>
<Manufacturing of resist ink>
[Example 9]
25.0 parts (solid content 27% by weight) of the pigment dispersion (C-1), 20.0 parts (solid content 30% by weight) of F-1 as the compound (F) containing a photopolymerizable functional group, new 20.0 parts of "A-9300" manufactured by Nakamura Chemical Co., Ltd. (prepared to a solid content of 30% by weight by PGMAc), 2.0 parts of "Irg907" manufactured by BASF Co., Ltd. as a photopolymerization initiator, and propylene glycol monomethyl ether as a solvent. Using 33.0 parts of acetate (hereinafter PGMAc), the mixture was stirred and mixed so as to be uniform, and filtered through a 1.0 μm filter to obtain a resist ink (D-1).

[Example 10]
25.0 parts (solid content 27% by weight) of the pigment dispersion (C-1), 20.0 parts (solid content 30% by weight) of F-1 as the compound (F) containing a photopolymerizable functional group, new 14.0 parts of "A-9300" manufactured by Nakamura Chemical Co., Ltd. (prepared to a solid content of 30% by weight by PGMAc), as a compound (B) containing an isocyanate group, "Death Module BL4265SN" manufactured by Sumika Cobestrourethane Co., Ltd. 2 Using .77 parts, 2.0 parts of BASF's "Irg907" as a photopolymerization initiator, and 36.23 parts of PGMAc as a solvent, the mixture was stirred and mixed so as to be uniform, and filtered through a 1.0 μm filter. A resist ink (D-2) was obtained.

[Examples 11-19, Comparative Examples 5-8]
The resist ink (D-) except that the type of the compound (F) containing the pigment dispersion (C) and the photopolymerizable functional group and the amount of the compound (B) containing the isocyanate group were changed as shown in Table 4. The resist inks (D-3 to D-11) and the comparative resist inks (D-12 to D-15) were adjusted in the same manner as in 1 and D-2).

The abbreviations in Table 4 are shown below.
PGMAc: Propylene Glycol Monomethyl Ether Acetate Irg907: 2-Methyl-1- (4-Methylthiophenyl) -2-morpholinopropan-1-one: Irgacure 907 (manufactured by BASF)
A-9300: 30% non-volatile content preparation of ethoxylated isocyanurate triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.), PGMAc solution BL4265SN: Block of IPDI-based polyisocyanate, 100-solution solvent naphtha solution with 65% non-volatile content, latent NCO group Content 8.1%: Death Module BL4265SN (manufactured by Sumika Cobestro Urethane)

<Evaluation of resist ink>

[Evaluation of viscosity over time]
For the resist inks of Examples 9 to 19 and Comparative Examples 5 to 8, the viscosities at the initial stage and after 1 month at room temperature were measured at 23 ° C. using an E-type viscometer (manufactured by Tokyo Keiki), and the degree of increase in viscosity with respect to the initial viscosity. Was calculated and evaluated. The evaluation ranks are as follows.
⊚: Increase rate is less than 5% (extremely good)
◯: Increase rate is 5% or more and less than 7% (good)
Δ: Increase rate is 7% or more and less than 10% (practical)
×: Increase rate is 10% or more (defective)

[Evaluation of heat resistance of coating film]
The resist inks of Examples 9 to 19 and Comparative Examples 5 to 8 were applied on a glass substrate having a thickness of 100 mm × 100 mm and a thickness of 1.1 mm using a spin coater, and then dried under reduced pressure. Subsequently, ultraviolet exposure was performed with an integrated light amount of 150 mJ / cm ² using an ultra-high pressure mercury lamp, and development was performed with an alkaline developer at 23 ° C. Then, it was heated at 220 ° C. for 30 minutes and allowed to cool to obtain a coated substrate for evaluation. The coating film substrate was prepared so as to meet y = 0.600 with a C light source after the heat treatment at 220 ° C. ^{The chromaticity ([L *} ₁ , a ^* ₁ , b ^* ₁ ]) of the obtained coating film at the C light source was measured using a microspectrophotometer (“OSP-SP100” manufactured by Olympus Optical Co., Ltd.). After that, as a heat resistance test, the mixture was heated at 230 ° C. for 1 hour, the chromaticity ([L ^* ₂ , a ^* ₂ , b ^* ₂ ]) with a C light source was measured, and the color difference ΔE ^* was calculated by the following formula. , The evaluation was made in the following four stages.
ΔE ^* = √ ((L ^* _2- L ^* ₁ ) ² + (a ^* _2- a ^* ₁ ) ² + (b ^* _2- b ^* ₁ ) ² )
⊚: ΔE ^* is less than 3.0 ○: ΔE ^* is 3.0 or more and less than 5.0 Δ: ΔE ^* is 5.0 or more and less than 10.0 ×: ΔE ^* is 10.0 or more

[Evaluation of chemical resistance of coating film]
A coating film substrate for evaluation was prepared in the same procedure as the evaluation of heat resistance. ^{The chromaticity ([L *} ₁ , a ^* ₁ , b ^* ₁ ]) of the obtained coating film at the C light source was measured using a microspectrophotometer (“OSP-SP100” manufactured by Olympus Optical Co., Ltd.). Then, it was immersed in propylene glycol monomethyl ether acetate at room temperature for 5 minutes, washed with ion-exchanged water, and air-dried. Next, visually observe the appearance, ^{measure the chromaticity ([L *} ₂ , a ^* ₂ , b ^* ₂ ^{]) with the C light source, obtain the color difference ΔE *} by the following formula, and evaluate in the following four stages. did.
ΔE ^* = √ ((L ^* _2- L ^* ₁ ) ² + (a ^* _2- a ^* ₁ ) ² + (b ^* _2- b ^* ₁ ) ² )
⊚: ΔE ^* is less than 3.0 ○: ΔE ^* is 3.0 or more and less than 5.0 Δ: ΔE ^* is 5.0 or more and less than 10.0 ×: ΔE ^* is 10.0 or more

As is clear from the above evaluation results, Examples 9 to 19 using the dispersant (A) containing an oxazolidinyl group of the present invention showed good storage stability, and the coating film was variously formed by cross-linking with an acryloyl group. It showed resistance (heat resistance, chemical resistance). In addition, Examples 10 to 13 and 15 to 19 in which the compound (B) containing an isocyanate group was added to the pigment dispersion or the ink composition all showed excellent chemical resistance, and among them, the isocyanate group was contained. Examples 11 and 16 to which a large amount of the compound (B) was added exhibited more excellent heat resistance. At this time, in Example 12 using the compound (F-2) containing a photopolymerizable functional group of Production Example 14, since F-2 contains a carboxylic acid, the storage stability is inferior. rice field. In Examples 9 to 11 and 13 to 19, F-1 has a phenolic hydroxyl group instead of a carboxylic acid, achieving both storage stability and various resistances.
On the other hand, it was found that the coating films of Comparative Examples 5 to 8 using the dispersant having no oxazolidinyl group had problems in the heat resistance test and the chemical resistance test.

<< Active energy ray-curable offset ink >>
<Manufacturing of active energy ray-curable offset ink>
[Example 20]
10 parts of pigment dispersant solution (A-4), 5 parts of diallyl phthalate resin (weight average molecular weight 50,000), 110 parts of a mixture of dipentaerythritol pentaacrylate: dipentaerythritol hexaacrylate = 15%: 85% (weight ratio) The upper limit temperature was kept at 100 ° C., and the mixture was heated and mixed to volatilize and dissolve the solvent in A-4 at the same time. 60 parts of this solution, 2-benzyl-2-dimethylamino-1- (morpholinophenyl) -butane-1-one, 10 parts, phthalocyanine blue, 20 parts, N-2- (aminoethyl) -3-aminopropyl. Mix 2 parts of trimethoxysilane, stir and mix using a butterfly mixer, disperse with 3 rolls so that the maximum particle size is 7.5 μm or less, and use a spread meter to achieve a constant viscosity standard. To prepare an active energy ray-curable offset ink (E-1).

[Comparative Example 9]
The active energy ray-curable offset ink (E) of Comparative Example 9 was prepared in the same manner as in Example 20 except that the pigment dispersant solution (A-9) was used instead of the pigment dispersant solution (A-4). -2) was obtained.

<Evaluation of active energy ray-curable offset ink>
After printing and applying a predetermined amount of ink to PP (Super Pure Ray SG140 manufactured by Idemitsu Co., Ltd.) and PET (Toyobo Ester Film E5100 manufactured by Toyobo Co., Ltd.) using an RI tester (simple printing transfer device), a metal halide of ^{160 W / cm 2} A print sample was prepared by irradiating with a lamp, and the water resistance and film strength were evaluated by the following methods. The evaluation results are shown in Table 5.

[Water resistance]
The print sample was immersed in a TOMY autoclave BS-325 at 120 ° C. for 40 minutes, and then the adhesion to PP and PET was evaluated by a cellophane tape peeling test according to the following criteria.
5: No peeling at all 4: Adhesion test part less than 10% peeling 3: Adhesion test part 50% or more peeling 2: Adhesion test part 80% or more peeling 1: All peeling

[Film strength]
The print sample was rubbed with MEK, and the number of times it rubbed off was confirmed. For those having sufficient film strength, it is assumed that the film is not scraped off 50 times or more and the film strength is strong, and if it is less than that, the film strength is sequentially inferior.

As shown in Table 5, Example 20 contains a compound (A) containing an oxazolidinyl group, a compound containing an acryloyl group as a photopolymerizable functional group, and a photopolymerizable initiator. Was also good. In Comparative Example 9, since the compound (A) containing an oxazolidinyl group was not contained, the water adhesion resistance and the film strength were insufficient.

The pigment dispersion of the present invention includes various inkjet inks such as organic solvent-based inks, water-based inks, and active energy ray-curable inks, which are required to have excellent dispersibility and various resistances (heat resistance, chemical resistance, etc.), resist inks, and offset inks. , Gravure ink, flexo ink, etc.

Claims (1)

An ink composition containing the following composition.
(1) A pigment dispersion containing a pigment, a pigment dispersant (A), and a liquid medium, wherein the pigment dispersant (A) is a polymer having a structural unit containing an oxazolidinyl group. body.
(2) Compound (B) containing an isocyanate group.