JP2016047922A - Composite particle for ink, ink composition and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide composite particles for ink that prevent dispersant from coming off them and have excellent dispersion stability, and an ink composition comprising the particles.SOLUTION: The composite particle for ink is a composite particle that comprises a polymer (A) and a pigment particle (B), where the pigment particle (B) has its surface coated with a coating layer comprising the polymer (A), an impregnation layer impregnated with the polymer (A) is provided from the surface to the inside of the pigment particle (B), and an average thickness of the impregnation layer is 0.1-50% of a volume average particle diameter of the composite particle.SELECTED DRAWING: None

Description

  The present invention relates to composite particles for ink, an ink composition, and a method for producing the same.

  In recent years, pigments are often selected as dyes for inks rather than dyes from the viewpoint of light resistance. However, in order to realize the photographic image quality characteristics using the pigment, a particle size of 100 nm or less is required. When the particle size of the pigment becomes finer, the surface energy of the pigment increases, so it becomes easy to re-aggregate even if it can be dispersed. Therefore, a method using a polymer dispersant has been proposed to stably disperse the pigment over a long period of time ( Patent Document 1). However, in the proposed method, the dispersion of the dispersant from the pigment surface occurs with time, so that the dispersion stability is insufficient, and there is a problem that the removed dispersant lowers the surface tension of the ink.

JP 2010-222405 A

  The object of the present invention is to solve the above-mentioned problems of the prior art. That is, an object of the present invention is to provide composite particles for ink that are excellent in dispersion stability without dropping off the dispersant, and an ink composition using the particles.

  As a result of intensive studies to achieve the above object, the present inventors have found the following. The present invention is a composite particle comprising a polymer (A) and pigment particles (B), wherein the surface of the pigment particles (B) is coated with a coating layer containing the polymer (A), and the pigment particles ( B) a composite particle for ink having an impregnation layer impregnated with the polymer (A) from the surface to the inside, wherein the average thickness of the impregnation layer is 0.1 to 50% of the volume average particle diameter of the composite particle. is there.

  According to the present invention, it is possible to provide composite particles that are excellent in adhesion between the coating layer and the pigment particles, that do not generate dropping components, and that are excellent in dispersion stability, and ink compositions that include the particles.

The present invention is described in detail below.
In the present invention, the polymer (A) is a polymer having the monomer (a) as a constituent monomer.

Although there is no restriction | limiting in particular as a monomer (a), For example, the following examples are mentioned and you may use 2 or more types together.
(A-1) Aliphatic hydrocarbon having a polymerizable double bond:
Chain hydrocarbons having polymerizable double bonds: Alkenes (for example, ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, octadecene, etc.); alkadienes having 4 to 30 carbon atoms (for example, butadiene, Isoprene, 1,4-pentadiene, 1,5-hexadiene and 1,7-octadiene).
Cyclic hydrocarbons having a polymerizable double bond: mono- or dicycloalkene (such as cyclohexene, vinylcyclohexene and ethylidenebicycloheptene) and mono- or dicycloalkadiene [such as (di) cyclopentadiene].

(A-2) Aromatic hydrocarbon having a polymerizable double bond:
Styrene; hydrocarbyl (alkyl, cycloalkyl, aralkyl and / or alkenyl having 1 to 30 carbon atoms) substitution of styrene (for example, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethylstyrene, isopropylstyrene, Butyl styrene, phenyl styrene, cyclohexyl styrene, benzyl styrene, crotyl benzene, divinyl benzene, divinyl toluene, divinyl xylene, and trivinyl benzene); and vinyl naphthalene.

(A-3) Monomers having a carboxyl group and a polymerizable double bond and their salts:
Unsaturated monocarboxylic acid {eg (meth) acrylic acid ["(meth) acryl" means acrylic or methacrylic. ], Crotonic acid, isocrotonic acid, cinnamic acid, etc.}; unsaturated dicarboxylic acids (anhydrides) [eg (anhydrous) maleic acid, fumaric acid, itaconic acid, (anhydrous) citraconic acid, mesaconic acid, etc.]; Monoalkyl esters of dicarboxylic acids (for example, maleic acid monomethyl ester, maleic acid monodecyl ester, fumaric acid monoethyl ester, itaconic acid monobutyl ester, citraconic acid monodecyl ester, etc.) and the like.

  (A-4) Examples of the salt constituting the monomer salt having a carboxyl group and a polymerizable double bond include alkali metal salts (sodium salt and potassium salt), alkaline earth metal salts (calcium salt and magnesium salt). Salts), ammonium salts, amine salts and quaternary ammonium salts.

  (A-5) The amine salt is not particularly limited as long as it is an amine compound. For example, primary amine salts (ethylamine salts, butylamine salts, octylamine salts, etc.), secondary amines (diethylamine salts, dibutylamine salts, etc.) Tertiary amines (such as triethylamine salt and tributylamine salt) can be mentioned. Examples of the quaternary ammonium salt include tetraethylammonium salt, triethyllaurylammonium salt, tetrabutylammonium salt, and tributyllaurylammonium salt.

  (A-6) As a salt of a monomer having a carboxyl group and a polymerizable double bond, sodium acrylate, sodium methacrylate, monosodium maleate, disodium maleate, potassium acrylate, potassium methacrylate, malein Acid monopotassium, lithium acrylate, cesium acrylate, ammonium acrylate, calcium acrylate, aluminum acrylate and the like.

(A-7) Monomers having a sulfo group and a polymerizable double bond and their salts:
Alkene sulfonic acid (eg vinyl sulfonic acid, (meth) allyl sulfonic acid and methyl vinyl sulfonic acid); styrene sulfonic acid and its alkyl derivatives (eg α-methyl styrene sulfonic acid etc .; sulfo (hydroxy) alkyl- (meth) acrylate) (For example, sulfopropyl (meth) acrylate, 2-hydroxy-3- (meth) acryloxypropylsulfonic acid, 2- (meth) acryloyloxyethanesulfonic acid, 3- (meth) acryloyloxy-2-hydroxypropanesulfonic acid, etc. ); Sulfo (hydroxy) alkyl (meth) acrylamide [eg 2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid and 3- (meth) acrylamide − -Hydroxypropanesulfonic acid, etc.]; alkylallylsulfosuccinic acid (for example, propylallylsulfosuccinic acid, butylallylsulfosuccinic acid, 2-ethylhexyl-allylsulfosuccinic acid, etc.); poly [n (degree of polymerization; the same applies hereinafter) = 2-30] Oxyalkylene (oxyethylene, oxypropylene, oxybutylene and the like. Oxyalkylene may be used alone or in combination. When used together, the addition type may be random addition or block addition.) Mono (meth) acrylate sulfate ester [for example, poly ( n = 5 to 15) oxyethylene monomethacrylate sulfate and poly (n = 5 to 15) oxypropylene monomethacrylate sulfate, etc.]; compounds represented by the following general formulas (1) to (3); and salts thereof Etc.
In addition, as a salt, what was illustrated as a salt which comprises the salt of the monomer which has (6) a carboxyl group and a polymerizable double bond is mentioned.

In the formula, R ¹ is an alkylene group having 2 to 4 carbon atoms, and when there are a plurality of R ¹ O, one type or two or more types may be used, and when two or more types are used in combination, the bonding type may be random or block. R ² and R ³ are each independently an alkyl group having 1 to 15 carbon atoms; m and n are each independently a number of 1 to 50; Ar is a benzene ring; R ⁴ is substituted with a fluorine atom. An alkyl group having 1 to 15 carbon atoms may be represented.

(A-8) Monomer having phosphono group and polymerizable double bond and salt thereof:
(Meth) acryloyloxyalkyl phosphoric acid monoester (such as 2-hydroxyethyl (meth) acryloyl phosphate and phenyl-2-acryloyloxyethyl phosphate), (meth) acryloyloxyalkylphosphonic acid (such as 2-acryloyloxyethyl phosphone) Acid etc.).
In addition, as a salt, what was illustrated as a salt which comprises the monomer which has (a-3) a carboxyl group and a polymerizable double bond is mentioned.

(A-9) Monomer having hydroxyl group and polymerizable double bond:
Hydroxystyrene, N-methylol (meth) acrylamide, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, (meth) allyl alcohol, crotyl alcohol, isocrotyl alcohol, 1- Buten-3-ol, 2-buten-1-ol, 2-butene-1,4-diol, propargyl alcohol, 2-hydroxyethylpropenyl ether, sucrose allyl ether, and the like.

(A-10) Nitrogen-containing monomer having a polymerizable double bond:
(A-10-1) Monomer having amino group and polymerizable double bond:
Aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, t-butylaminoethyl methacrylate, N-aminoethyl (meth) acrylamide, (meth) allylamine, morpholinoethyl (meth) acrylate, 4-vinylpyridine, 2-vinylpyridine, crotylamine, N, N-dimethylaminostyrene, methyl-α-acetaminoacrylate, vinylimidazole, N-vinylpyrrole, N-vinylthiopyrrolidone, N-arylphenylenediamine, aminocarbazole Aminothiazole, aminoindole, aminopyrrole, aminoimidazole, aminomercaptothiazole, and salts thereof.
(A-10-2) Monomer having amide group and polymerizable double bond:
(Meth) acrylamide, N-methyl (meth) acrylamide, N-butyl acrylamide, diacetone acrylamide, N-methylol (meth) acrylamide, N, N′-methylene-bis (meth) acrylamide, cinnamic amide, N, N -Dimethylacrylamide, N, N-dibenzylacrylamide, methacrylformamide, N-methyl-N-vinylacetamide, N-vinylpyrrolidone and the like.
(A-10-3) Monomer having a nitrile group and a polymerizable double bond:
(Meth) acrylonitrile, cyanostyrene, cyanoacrylate and the like.
(A-10-4) Monomer having nitro group and polymerizable double bond:
Nitrostyrene etc.

(A-11) A monomer having a lactam group and a polymerizable double bond:
N-vinylcaprolactam etc. are mentioned.
(A-12) Monomer having lactone group and polymerizable double bond:
Examples thereof include γ-butyrolactone (meth) acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate.

(A-12) Monomer having an epoxy group and a polymerizable double bond:
Glycidyl (meth) acrylate and p-vinylphenylphenyl oxide.

(A-13) Monomer having halogen element and polymerizable double bond:
Vinyl chloride, vinyl bromide, vinylidene chloride, allyl chloride, chlorostyrene, bromostyrene, dichlorostyrene, chloromethylstyrene, tetrafluorostyrene, chloroprene and the like.

(A-14) An ester having a polymerizable double bond, an ether having a polymerizable double bond, a ketone having a polymerizable double bond, and a sulfur-containing compound having a polymerizable double bond:
(A-15-1) Ester having a polymerizable double bond:
Vinyl acetate, vinyl propionate, vinyl butyrate, diallyl phthalate, diallyl adipate, isopropenyl acetate, vinyl methacrylate, methyl-4-vinyl benzoate, cyclohexyl methacrylate, benzyl methacrylate, phenyl (meth) acrylate, vinyl methoxyacetate, vinyl benzoate, ethyl -Α-ethoxyacrylate, alkyl (meth) acrylate having an alkyl group having 1 to 50 carbon atoms [methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl ( (Meth) acrylate, dodecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate and eicosyl (meth) a Relate, etc.], dialkyl fumarate (two alkyl groups are linear, branched or alicyclic groups having 2 to 8 carbon atoms), dialkyl maleate (two alkyl groups are carbon atoms 2-8 linear, branched or alicyclic groups), poly (meth) allyloxyalkanes (diallyloxyethane, triaryloxyethane, tetraallyloxyethane, tetraallyloxypropane, tetra Allyloxybutane and tetrametaallyloxyethane), etc., such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, monomers having a polyalkylene glycol chain and a polymerizable double bond [polyethylene glycol mono (meth) acrylate , Polypropylene glycol monoacrylate, methyl alcohol EO adduct (meth) acrylate, methyl alcohol LUCOL PO adducts (meth) acrylates, etc.], poly (meth) acrylates [poly (meth) acrylates of polyhydric alcohols: ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, neopentyl glycol di ( Meth) acrylate, trimethylolpropane tri (meth) acrylate and polyethylene glycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc.] Can be mentioned.
(A-15-2) Ether having a polymerizable double bond:
Vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, vinyl butyl ether, vinyl-2-ethylhexyl ether, vinyl phenyl ether, vinyl-2-methoxyethyl ether, methoxybutadiene, vinyl-2-butoxyethyl ether, 3,4-dihydro -1,2-pyran, 2-butoxy-2′-vinyloxydiethyl ether, acetoxystyrene, phenoxystyrene, and the like.
(A-15-3) Ketone having a polymerizable double bond:
Examples include vinyl methyl ketone, vinyl ethyl ketone, and vinyl phenyl ketone.
(A-15-4) Sulfur-containing compound having a polymerizable double bond:
Examples thereof include divinyl sulfide, p-vinyl diphenyl sulfide, vinyl ethyl sulfide, vinyl ethyl sulfone, divinyl sulfone, and divinyl sulfoxide.

(A-16) Monomer having an isocyanate group or a blocked isocyanate group and a polymerizable double bond:
2-isocyanatoethyl methacrylate, 2-isocyanatoethyl acrylate, 2- (O- [1′-methylpropylideneamino] carboxyamino) ethyl methacrylate, 2-[(3,5-dimethylpyrazolyl) carbonylamino] Examples include ethyl methacrylate and 1,1- (bisacryloyloxymethyl) ethyl isocyanate.

(A-17) Monomer having an epoxy group:
Examples of mono- and polyepoxides include aromatic epoxy compounds, heterocyclic epoxy compounds, alicyclic epoxy compounds, and aliphatic epoxy compounds. Examples of the aromatic polyepoxy compounds include glycidyl ethers and glycidyl ethers of polyhydric phenols, glycidyl aromatic polyamines, and glycidylates of aminophenols.

(A-18) Monomer having an amino group:
Examples of chain aliphatic monoamines include methylamine, etheramine, ethylamine, dimethylamine, trimethylamine, and triethanolamine.
Examples of chain aliphatic diamines include alkylene diamines (ethylene diamine, propylene diamine, trimethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and polyalkylene polyamines [diethylene triamine, iminobispropylamine, bis (hexamethylene) triamine, triethylene. Tetramine, tetraethylenepentamine, pentaethylenehexamine, etc.].
Examples of the cycloaliphatic monoamine include cyclohexylamine.
Cycloaliphatic polyamines include alicyclic diamines {1,3-diaminocyclohexane, isophorone diamine, mensen diamine, 4,4′-methylene dicyclohexane diamine (hydrogenated methylene dianiline) and 3,9-bis (3 -Aminopropyl) -2,4,8,10-tetraoxaspiro [5,5] undecane etc.} and heterocyclic diamines [piperazine, N-aminoethylpiperazine, 1,4-diaminoethylpiperazine, and 1,4 -Bis (2-amino-2-methylpropyl) piperazine etc.] and the like.
Examples of the aromatic monoamine include unsubstituted aromatic monoamines, aromatic monoamines having an alkyl group (alkyl groups having 1 to 4 carbon atoms such as methyl group, ethyl group, n- or isopropyl group, and butyl group).
Examples of the aromatic diamine include unsubstituted aromatic diamines, and aromatic diamines having an alkyl group (an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n- or isopropyl group, and a butyl group).
An unsubstituted aniline etc. are mentioned as an unsubstituted aromatic monoamine.
The unsubstituted heterocyclic monoamines include aminopyridine, aminopyrazine, aminopyrimidine, aminopyridazine, triazole, pyrrole, imidazoline, pyrazole, aminoindolizine, aminoisoindole, aminoindole, aminopurine, aminoquinoline, aminoisoquinoline, amino Examples include thiophene, aminofuran, aminopyran, and various amino acids.
Examples of the unsubstituted aromatic diamine include 1,2-, 1,3- or 1,4-phenylenediamine, 2,4′- or 4,4′-diphenylmethanediamine, diaminodiphenylsulfone, benzidine, thiodianiline, bis (3 , 4-diaminophenyl) sulfone, 2,6-diaminopyridine, m-aminobenzylamine, naphthylenediamine and mixtures thereof.
Examples of unsubstituted heterocyclic diamines include diaminopyridine, diaminopyrazine, diaminopyrimidine, diaminopyridazine, aminotriazole, aminopyrrole, aminoimidazoline, aminopyrazole, diaminoindolizine, diaminoisoindole, diaminoindole, diaminopurine, diaminoquinoline, Examples include diaminoisoquinoline, diaminothiophene, diaminofuran, diaminopyran, and various amino acids.
Aromatic monoamines having an alkyl group (alkyl group having 1 to 4 carbon atoms such as methyl, ethyl, n- or isopropyl and butyl) include toluidine, ethylaniline, isopropylaniline, tert-butylaniline, tert -Pentylaniline and the like.
The aromatic diamine having an alkyl group (alkyl group having 1 to 4 carbon atoms such as methyl group, ethyl group, n- or isopropyl group and butyl group) includes 2,4- or 2,6-tolylenediamine, crude Tolylenediamine, diethyltolylenediamine, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-bis (o-toluidine), dianisidine, diaminoditolylsulfone, 1,3-dimethyl-2 , 4-diaminobenzene, 1,3-diethyl-2,4-diaminobenzene, 1,3-dimethyl-2,6-diaminobenzene, 1,4-diethyl-2,5-diaminobenzene, 1,4-diisopropyl -2,5-diaminobenzene, 1,4-dibutyl-2,5-diaminobenzene, 2,4-diaminomesitylene, 1,3,5-triethyl- , 4-diaminobenzene, 1,3,5-triisopropyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2 , 6-diaminobenzene, 2,3-dimethyl-1,4-diaminonaphthalene, 2,6-dimethyl-1,5-diaminonaphthalene, 2,6-diisopropyl-1,5-diaminonaphthalene, 2,6-dibutyl -1,5-diaminonaphthalene, 3,3 ′, 5,5′-tetramethylbenzidine, 3,3 ′, 5,5′-tetraisopropylbenzidine, 3,3 ′, 5,5′-tetramethyl-4 , 4′-diaminodiphenylmethane, 3,3 ′, 5,5′-tetraethyl-4,4′-diaminodiphenylmethane, 3,3 ′, 5,5′-tetraisopropyl-4,4′-diaminodipheni Methane, 3,3 ′, 5,5′-tetrabutyl-4,4′-diaminodiphenylmethane, 3,5-diethyl-3′-methyl-2 ′, 4-diaminodiphenylmethane, 3,5-diisopropyl-3′- Methyl-2 ′, 4-diaminodiphenylmethane, 3,3′-diethyl-2,2′-diaminodiphenylmethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 3,3 ′, 5,5′- Tetraethyl-4,4′-diaminobenzophenone, 3,3 ′, 5,5′-tetraisopropyl-4,4′-diaminobenzophenone, 3,3 ′, 5,5′-tetraethyl-4,4′-diaminodiphenyl ether 3,3 ′, 5,5′-tetraisopropyl-4,4′-diaminodiphenyl sulfone and mixtures thereof.

(A-19) Monomer having an isocyanate group:
Monoisocyanates include aromatic monoisocyanates, aliphatic monoisocyanates, modified products of these monoisocyanates (urethane groups, carbodiimide groups, allophanate groups, urea groups, burette groups, uretdione groups, uretoimine groups, isocyanurate groups, and oxazolidones. Group-containing modified products) and mixtures of two or more thereof.
Diisocyanates include aromatic diisocyanates, aliphatic diisocyanates, modified products of these diisocyanates (urethane groups, carbodiimide groups, allophanate groups, urea groups, burette groups, uretdione groups, uretoimine groups, isocyanurate groups, and oxazolidone group-containing modified products. Etc.) and mixtures of two or more thereof.
Aromatic diisocyanates include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI), crude TDI, m- or p-xylylene diisocyanate (XDI), α , Α, α ′, α′-tetramethylxylylene diisocyanate (TMXDI), 2,4′- or 4,4′-diphenylmethane diisocyanate (MDI), crude MDI {crude diaminophenylmethane [formaldehyde and aromatic amine (aniline) ) Or a mixture thereof and a mixture thereof.
Examples of the aliphatic diisocyanate include a chain aliphatic diisocyanate and a cyclic aliphatic diisocyanate.
Examples of chain aliphatic diisocyanates include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and 2,6-diisocyanatomethylcaproate. Bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate, and mixtures thereof.
Cycloaliphatic diisocyanates include isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4′-diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), and bis (2-isocyanatoethyl). -4-cyclohexene-1,2-dicarboxylate, 2,5- or 2,6-norbornane diisocyanate, and mixtures thereof.
As the modified product of diisocyanate, a modified product containing a urethane group, a carbodiimide group, an allophanate group, a urea group, a burette group, a uretdione group, a uretoimine group, an isocyanurate group and / or an oxazolidone group is used. Urethane-modified MDI, carbodiimide-modified MDI, trihydrocarbyl phosphate-modified MDI, etc.), urethane-modified TDI, and mixtures thereof [for example, mixtures of modified MDI and urethane-modified TDI (isocyanate-containing prepolymer)] and the like.

(A-20) Diol:
Examples of the diol include alkylene glycols having 2 to 30 carbon atoms (for example, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, octanediol, decanediol). , Dodecanediol, tetradecanediol, neopentyl glycol, 2,2-diethyl-1,3-propanediol, etc.); number average molecular weight (hereinafter abbreviated as Mn) = 106 to 10,000 alkylene ether glycol (for example, diethylene glycol, Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols having 6 to 24 carbon atoms (for example, 1,4-cyclohexanedimethano) And hydrogenated bisphenol A, etc.); Mn = 100-10,000 alkylene oxide (hereinafter abbreviated as AO) adduct (addition mole number 2-100) [for example, 1,4-cyclohexanedi] Ethylene oxide of methanol (hereinafter abbreviated as EO) 10 mol adduct, etc.]; Bisphenols having 15 to 30 carbon atoms (bisphenol A, bisphenol F, bisphenol S, etc.) or polyphenols having 12 to 24 carbon atoms (for example, catechol, hydroquinone) ASO [EO, propylene oxide (hereinafter abbreviated as PO), butylene oxide (hereinafter abbreviated as BO), etc.] adducts (addition mole number 2 to 100) (for example, bisphenol A · EO 2 to 4 mole addition) And bisphenol A · PO 2-4 mol adduct ); Abbreviated as weight average molecular weight (hereinafter Mw) = 100 to 5,000 polylactone diols (such as poly -ε- caprolactone diol); polybutadiene diol of Mw = 1,000 to 20,000 and the like.

(A-21) Carboxylic acid:
Examples of monocarboxylic acids include alkane dicarboxylic acids having 4 to 32 carbon atoms; alkene dicarboxylic acids having 4 to 32 carbon atoms; branched alkene carboxylic acids having 8 to 40 carbon atoms; branched alkane carboxylic acids having 12 to 40 carbon atoms; Examples include 8 to 20 aromatic carboxylic acids.
Examples of the dicarboxylic acid include alkane dicarboxylic acids having 4 to 32 carbon atoms (for example, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, and octadecanedicarboxylic acid); alkenedicarboxylic acids having 4 to 32 carbon atoms (for example, maleic acid). Acid, fumaric acid, citraconic acid, mesaconic acid, etc.); branched alkene dicarboxylic acid having 8 to 40 carbon atoms [eg dimer acid, alkenyl succinic acid (dodecenyl succinic acid, pentadecenyl succinic acid, octadecenyl succinic acid, etc.) Branched alkane dicarboxylic acids having 12 to 40 carbon atoms [eg alkyl succinic acid (decyl succinic acid, dodecyl succinic acid and octadecyl succinic acid etc.); aromatic dicarboxylic acids having 8 to 20 carbon atoms (eg phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid) It is.

(A-22) Silane coupling agent:
Silane coupling agents include alkoxysilanes, vinyl groups, epoxy groups, styryl groups, (meth) acryloyl groups, amino groups, isocyanurate groups, ureido machines, mercapto groups, sulfide groups, isocyanate groups, carboxyl groups, etc. A silane coupling agent having Specific examples of the silane coupling agent include trimethoxysilylbenzoic acid, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- ( 3,4-epoxycyclohexyl) ethyltrimethoxysilane and the like.

(A-23) Lactam:
ε-caprolactam and the like can be mentioned.

  The precursor (A0) of the polymer (A) used in the present invention includes a polymer having the monomer (a) as a constituent monomer, and may be a mixture with the monomer (a). .

  Examples of the pigment particles (B) used in the present invention include pigment particles containing inorganic pigments, organic pigments and the like. More specifically, a black pigment, a yellow ink pigment, a magenta ink pigment, a cyan ink pigment, and the like can be given.

  The shape of the pigment particles (B) is not particularly limited, and examples thereof include granular, porous, plate-like, or fiber-like shapes.

  Examples of inorganic pigments include carbon black, titanium oxide, zinc white, zinc oxide, tripone, iron oxide, aluminum oxide, silicon dioxide, kaolinite, montmorillonite, talc, barium sulfate, calcium carbonate, silica, alumina, cadmium red, Bengara, molybdenum red, chrome vermilion, molybdate orange, yellow lead, chrome yellow, cadmium yellow, yellow iron oxide, titanium yellow, chromium oxide, pyridian, cobalt green, titanium cobalt green, cobalt chrome green, ultramarine blue, ultramarine blue , Bitumen, cobalt blue, cerulean blue, manganese violet, cobalt violet, mica and the like.

  Examples of organic pigments include azo, azomethine, polyazo, phthalocyanine, quinacridone, anthraquinone, indigo, thioindigo, quinophthalone, benzimidazolone, isoindoline, and isoindolinone pigments. Etc.

  Examples of black pigments include, for example, carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, and metals such as copper and iron (CI pigment black 11). And metal compounds such as titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1).

  Examples of commercially available carbon black include No. 2300, no. 900, MCF-88, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B (all manufactured by Mitsubishi Chemical Corporation); Raven700, 5750, 5250, 5000, 3500, 1255 (all manufactured by Columbia); Regal400R, 330R, 660R, Mogu L, Monarch700, 800, 880, 900, 1000, 1100, 1300, Monarch 1400 (all manufactured by Cabot Corporation); Color Black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Printex 35, U, V, 140U, 140V, Special Black 6, 5, 4A, and 4 (all manufactured by Degussa).

  There is no restriction | limiting in particular as a pigment for yellow ink, According to the objective, it can select suitably. Examples thereof include C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 174, C.I. I. Pigment yellow 180, C.I. I. And CI Pigment Yellow 185.

  There is no restriction | limiting in particular as a pigment for magenta ink, According to the objective, it can select suitably. Examples thereof include C.I. I. Pigment red 5, C.I. I. Pigment red 7, C.I. I. Pigment red 12, C.I. I. Pigment red 48 (Ca), C.I. I. Pigment red 48 (Mn), C.I. I. Pigment red 57 (Ca), C.I. I. Pigment red 57: 1, C.I. I. Pigment red 112, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 146, C.I. I. Pigment red 168, C.I. I. Pigment red 176, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment red 202, pigment violet 19, and the like.

  There is no restriction | limiting in particular as a pigment for cyan inks, According to the objective, it can select suitably. Examples thereof include C.I. I. Pigment blue 1, C.I. I. Pigment blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15:34, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. Pigment blue 60, C.I. I. Pigment blue 63, C.I. I. Pigment blue 66; C.I. I. Bat Blue 4, C.I. I. Bat Blue 60 and the like.

  In addition, pigments newly produced for the present invention may be used. Moreover, you may use together the pigment mentioned above in the range which does not impair an effect.

  In the present invention, in order to form the impregnated layer on the pigment particles (B), a known dispersion method may be used regardless of a method, but a method of pressurizing with a penetrating solvent, liquid, subcritical or supercritical Examples thereof include a method using carbon dioxide, and among these, a method using liquid, subcritical or supercritical carbon dioxide is preferable. The components that form the impregnated layer by these methods need to penetrate from the surface of the pigment particles (B) to the inside. In order to permeate, there is no particular limitation as long as it is non-crystalline or deficient and can penetrate the permeating solvent or liquid, subcritical or supercritical carbon dioxide, but the pigment particles (B) from the viewpoint of adhesion of the coating film The surface of is coated with a coating layer containing the polymer (A), and an impregnation layer impregnated with the polymer (A) is impregnated from the surface of the pigment particles (B). The average thickness of the impregnated layer is 0.1 to 50% of the volume average particle diameter of the composite particles. From the viewpoint of dispersion stability, the lower limit is preferably 0.6% or more of the volume average particle diameter (D50) of the composite particles, more preferably 2.0% or more, and particularly preferably 3.0% or more. In the case of pigments, the upper limit is preferably 45% or less of the volume average particle diameter (D50) of the composite particles, more preferably 30% or less, particularly preferably 20%, from the viewpoint of the physical properties of solid particles such as color developability It is as follows. The average thickness of the impregnated layer is the thickness of the impregnated layer impregnated with the polymer (A) from the surface of the pigment particle (B) to the inside, and the average length of the impregnated layer from the surface of the pigment particle (B) is averaged. It is the value. The thickness of the impregnated layer is a value obtained by photographing the composite particle using a scanning transmission electron microscope and analyzing the image. The average thickness of the impregnated layer can be adjusted by adjusting the pressure and treatment time for impregnation of the polymer (A) into the pigment with a penetrating solvent or liquid, subcritical or supercritical carbon dioxide.

The volume average particle diameter (D50) of the composite particles is preferably 10 nm or more and less than 500 nm from the viewpoint of the coloring power of the pigment. More preferably, it is 15 nm or more and less than 450 nm. Particularly preferably, it is 20 nm or more and less than 400 nm.
The volume average particle size (D50) of the composite particles is a value measured by a dynamic light scattering method with a particle size measuring device LB-550 manufactured by Horiba, Ltd. in an environment of 23 ° C. and 55% RH.

  As a method for forming the coating layer, the pigment particle (B) is added to the monomer (a) (or the polymer (A) precursor (A0)), more preferably the monomer (a) (or the polymer (A). ) Precursor (A0)), and more preferably the monomer (a) is impregnated in the solvent and penetrating solvent or liquid, subcritical or supercritical carbon dioxide, after impregnation or Examples thereof include a method of forming a coating layer having an impregnated layer by reacting simultaneously.

  The volume average particle diameter (D50) of the composite particles can be adjusted by selecting the primary particle diameter of the pigment particles (B) and adjusting the amount of the monomer (a).

  In the present invention, the mixture of pigment particles and penetrating solvent or liquid, subcritical or supercritical carbon dioxide is composed of at least pigment particles and penetrating solvent or liquid, subcritical or supercritical carbon dioxide, and the pigment particles are in the mixture. If present as a solid, for example, an inert gas, a solvent or the like may be used in combination to adjust physical property values (viscosity, diffusion coefficient, dielectric constant, solubility, interfacial tension).

The penetrating solvent can be selected from known solvents, but a solvent that dissolves the pigment to be treated cannot be used. When the penetrating solvent is used, the pigment particles (B) can be impregnated with the monomer (a) (or the precursor (A0) of the polymer (A)) by treating the pressure at a pressure of 2 MPa or more and 800 MPa. .
Therefore, it is preferable that the solubility of the pigment to be treated has a solubility of 20% by weight or less, more preferably 15% by weight or less, and particularly preferably 10% by weight or less.
<Method of dissolution test>
90 parts of a penetrating solvent can be stirred for 3 hours at a temperature of the processing conditions with respect to 10 parts of the pigment, and the solubility of the pigment can be calculated from the amount of evaporation residue in the supernatant.

  Examples of the inert gas include inert gases such as nitrogen, helium, argon, and air. The weight fraction of carbon dioxide in the total of carbon dioxide and other substances is preferably 70% by weight or more, more preferably 80% by weight or more, and particularly preferably 90% by weight or more.

  The initiator (D) in the present invention is not particularly limited as long as it is soluble in a liquid, subcritical or supercritical carbon dioxide, or a mixture with a solvent (S), and examples thereof include the following compounds.

Initiator (D):
Examples of the photopolymerization initiator (D-1) include acetophenone derivatives, acylphosphine oxide derivatives, titanocene derivatives, and combinations thereof.
Examples of the acetophenone derivative include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, acetophenone, 2,2 -Dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, benzyldimethyl ketal, 2-hydroxy-2-methylpropiophenone, 4-isopropyl-2-hydroxy-2-methylpropiophenone, 2-methyl- 1- (4- (methylthio) phenyl) -2-morpholino-1-propanone, dimethylbenzyl ketal, methylbenzoyl formate, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) - butan-1-one] and the like.
Examples of the acylphosphine oxide derivative include 2,4,6, -trimethylbenzoyl-diphenyl-phosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide.
Examples of the titanocene derivative include bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium.
As the thermal polymerization initiator (D-2), an azo polymerization initiator [for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2, 2'-azobis [N- (2-carboxyethyl) 2-methylpropionamidine] hydrate, 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis [2- (2- Imidazolin-2-yl) propane] dihydrochloride, 1,1-azobis (1-acetoxy-1-phenylethane), dimethyl-2,2′-azobisisobutyrate, 4,4′-azobis-4-cyano Valeric acid, azobiscyanovaleric acid, etc.)], and organic peroxide polymerization initiators [for example, benzoyl peroxide, di-t-butyl peroxide, t-butyl peroxide] And xylbenzoate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, etc.].
Examples of the acid generator (D-3) include an onium salt thermal acid generator, a sulfonium salt photoacid generator, an iodonium salt photoacid generator, a diazosulfonic acid photoacid generator, and a triphenylsulfonium light. An acid generator etc. are mentioned.
Examples of the base generator (D-4) include guanidinium derivatives, imidazole derivatives, piperidine derivatives, and carbamate derivatives.
Examples of the redox initiator (D-5) include persulfate, hydrogen peroxide, hydroperoxide, alkyl peroxide, diacyl peroxide and the like as the oxidizing agent, and iron (II) salt as the reducing agent, Examples thereof include sodium hydrogen sulfate, tertiary amine, naphthenate, mercaptan, triethylaluminum, alcohol, polyamine, and the like, and any oxidizing agent and reducing agent can be combined.

  The solvent (S) in the present invention is not particularly limited, and is a liquid at room temperature and normal pressure. For example, ketone solvents (acetone, methyl ethyl ketone, etc.), ether solvents (tetrahydrofuran, diethyl ether, ethylene glycol monoalkyl ether, propylene glycol) Monoalkyl ether, cyclic ether, etc.), ester solvent (acetate ester, pyruvate ester, 2-hydroxyisobutyrate ester, lactate ester, etc.), amide solvent (dimethylformamide, etc.), alcohol solvent (methanol, ethanol, isopropanol, fluorine-containing) Alcohol, etc.), aromatic hydrocarbon solvents (toluene, xylene, etc.), aliphatic hydrocarbon solvents (octane, decane, etc.), water, and mixtures thereof.

  In the present invention, together with pigment particles, if necessary, additives that do not impair the effects of the present invention [dispersant, leveling agent, plasticizer, antistatic agent, charge control agent, ultraviolet absorber, antiblocking agent, heat resistance stability Agents, flame retardants, fillers, etc.) may be used.

  There is no limitation in particular as a dispersing agent, A well-known thing can be used. The method for adding the dispersant is not particularly limited, and a known method can be selected. However, when using the method for producing composite particles (C1) using liquid, subcritical or supercritical carbon dioxide, pigment particles (B If the dispersant is added in the step before it comes into contact with the liquid, subcritical or supercritical carbon dioxide, the performance of the dispersant can be more effectively exhibited. From the viewpoint of dispersion stability, the amount of the dispersant added is preferably 0.01 to 100% by weight, more preferably 0.02 to 80% by weight, and particularly preferably 0.03 to 50% by weight based on the weight of the pigment. It is. The range of the preferable weight average molecular weight of a dispersing agent is 500-1 million, More preferably, it is 800-200,000, Especially preferably, it is 1000-100,000. Within this range, the dispersion stabilizing effect is improved.

  By dispersing the composite particles for ink of the present invention in the solvent (S) and the monomer (a), an ink composition containing the composite particles for ink can be obtained.

The ink composition of the present invention may contain other components appropriately selected as necessary. Examples include solvent (S), monomer (a), water-soluble organic solvent, dispersant, penetrant, pH adjuster, water-dispersible resin, antiseptic / antifungal agent, chelating reagent, rust inhibitor, oxidation Examples thereof include an inhibitor, an ultraviolet absorber, an oxygen absorber, and a light stabilizer.
<Water-soluble organic solvent>
When the medium of the ink composition is water, a water-soluble organic solvent can be contained for the purpose of preventing the ink composition from drying and improving the dispersion stability of the pigment. The water-soluble organic solvent is not particularly limited and can be appropriately selected depending on the purpose.

  The water-soluble organic solvent is preferably a polyhydric alcohol. Such a polyhydric alcohol is not particularly limited and may be appropriately selected depending on the purpose. Examples of the water-soluble organic solvent A include 1,2,3-butanetriol, 1,2,4-butanetriol. (Bp 190 ° C. to 191 ° C./24 hPa), glycerin (bp 290 ° C.), diglycerin (bp 270 ° C./20 hPa), triethylene glycol (bp 285 ° C.), tetraethylene glycol (bp 324 to 330 ° C.), diethylene glycol (bp 245 ° C.), 1 , 3-butanediol (bp 203 ° C to 204 ° C).

In addition to the water-soluble organic solvent, the ink composition may be replaced with a part of these water-soluble organic solvents or, in addition to these water-soluble organic solvents, other water-soluble organic solvents or A solid wetting agent can be used in combination.
Examples of the water-soluble organic solvent or solid wetting agent include polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, sulfur-containing compounds, and propylene carbonate. , Ethylene carbonate, and other water-soluble organic solvents.

Examples of the polyhydric alcohol include dipropylene glycol (bp 232 ° C.), 1,5-pentanediol (bp 242 ° C.), 3-methyl-1,3-butanediol (bp 203 ° C.), propylene glycol (bp 187 ° C.), 2-methyl-2,4-pentanediol (bp 197 ° C.), ethylene glycol (bp 196 ° C. to 198 ° C.), tripropylene glycol (bp 267 ° C.), hexylene glycol (bp 197 ° C.), polyethylene glycol (viscous liquid to solid) , Polypropylene glycol (bp 187 ° C.), 1,6-hexanediol (bp 253 ° C. to 260 ° C.), 1,2,6-hexane triol (bp 178 ° C.), trimethylol ethane (solid, mp 199 ° C. to 201 ° C.), trimethylol Propane (solid, mp 61 ° C And the like.
Examples of the polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether (bp 135 ° C.), ethylene glycol monobutyl ether (bp 171 ° C.), diethylene glycol monomethyl ether (bp 194 ° C.), diethylene glycol monobutyl ether (bp 231 ° C.), ethylene glycol mono -2-ethylhexyl ether (bp 229 ° C.), propylene glycol monoethyl ether (bp 132 ° C.) and the like.
There is no restriction | limiting in particular in content of the water-soluble organic solvent in an ink composition, Although it can select suitably according to the objective, 1 to 50 weight% is preferable.
(Dispersant)
Examples of the dispersant include various surfactants such as an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant, and polymer-type dispersants.
Examples of the anionic surfactant include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acyl amino acids and salts thereof, N-acyl methyl taurate, polyoxyalkyl ether sulfates. Salt, polyoxyethylene alkyl ether phosphate, rosin acid soap, castor oil sulfate ester salt, lauryl alcohol sulfate ester salt, alkylphenol type phosphate ester, naphthalenesulfonate formalin condensate, alkyl type phosphate ester, alkylallylsulfone hydrochloride, diethyl Examples include sulfosuccinate, diethylhexyl sulfosuccinate, and dioctyl sulfosuccinate. Examples of the cationic surfactant include 2-vinylpyridine derivatives and poly-4-vinylpyridine derivatives.

Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine, imidazoline. Derivatives and the like.
Examples of nonionic surfactants include the following.
Ether-based interfaces such as polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl ether, polyoxyallylalkyl alkyl ether Active agent;
Polyoxyethylene oleic acid, polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate Ester surfactants such as
2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-1-hexyn-3-ol Acetylene glycol surfactants such as

(Penetration agent)
The penetrant preferably contains either a polyol compound having 8 to 11 carbon atoms or a glycol ether compound having 8 to 11 carbon atoms.
Unlike the wetting agent, the penetrating agent has lower wettability than the wetting agent, and can be referred to as a “non-wetting agent-based medium”. As the penetrant, 2-ethyl-1,3-hexanediol [2,2,4-trimethyl-1,3-pentanediol is particularly preferable.
Other preferred examples include 2-ethyl-2-methyl-1,3-propanediol, 3,3-dimethyl-1,2-butanediol, 2,2-diethyl-1,3-propanediol, 2- Such as methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 2,5-dimethyl-2,5-hexanediol, 5-hexene-1,2-diol, etc. Aliphatic diols are mentioned.

Other penetrants that can be used in combination are not particularly limited as long as they can be dissolved in the ink composition and adjusted to desired physical properties, and can be appropriately selected according to the purpose. Examples thereof include alkyls and aryls of polyhydric alcohols such as diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, and tetraethylene glycol chlorophenyl ether. And ethers, lower alcohols such as ethanol, and the like.
The content of the penetrant in the ink composition is preferably 0.1 to 4.0% by weight. If the content is less than 0.1% by weight, quick-drying may not be obtained and a blurred image may be obtained. If the content exceeds 4.0% by weight, the dispersion stability of the pigment is impaired and the nozzle is easily clogged. Or the permeability to the recording medium is unnecessarily high, and the image density may be lowered or the back-through may occur.

(PH adjuster)
The pH adjuster is not particularly limited as long as it can adjust the pH to 8.5 to 11 and preferably 9 to 11 without adversely affecting the prepared ink composition, and is appropriately selected according to the purpose. can do. The pH can be measured with a pH meter (for example, HM-30R: manufactured by TOA-DKK).

Examples of pH adjusting agents include alcohol amines, alkali metal hydroxides, ammonium hydroxides, phosphonium hydroxides, alkali metal carbonates, and the like.
Examples of the alcohol amines include diethanolamine, triethanolamine, 2-amino-2-ethyl-1,3-propanediol, and the like. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Examples of the ammonium hydroxide include ammonium hydroxide and quaternary ammonium hydroxide. Examples of the phosphonium hydroxide include quaternary phosphonium hydroxide. Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, and potassium carbonate.

(Water dispersible resin)
As the water-dispersible resin, those having excellent film-forming properties (image forming properties) and having high water repellency, high water resistance, and high weather resistance have high water resistance and high image density (high color developability). It is useful for image recording, and examples thereof include condensation-type synthetic resins, addition-type synthetic resins, and natural polymer compounds.
Examples of the condensed synthetic resin include polyester resin, polyurethane resin, polyepoxy resin, polyamide resin, polyether resin, poly (meth) acrylic resin, acrylic-silicone resin, and fluorine-based resin. Examples of the addition type synthetic resin include polyolefin resins, polystyrene resins, polyvinyl alcohol resins, polyvinyl ester resins, polyacrylic acid resins, unsaturated carboxylic acid resins, and the like. Examples of the natural polymer compound include celluloses, rosins, and natural rubber. Among these, polyurethane resin fine particles, acrylic resin particles, acrylic-silicone resin fine particles, and fluorine-based resin fine particles are particularly preferable.

The volume average particle size (D50) of the water-dispersible resin is preferably 50 nm or more and 200 nm or less so that the ink composition does not have an excessively high viscosity. The volume average particle size (D50) here is a value measured by a dynamic light scattering method with a particle size measuring device LB-550 manufactured by Horiba, Ltd. in an environment of 23 ° C. and 55% RH.
The content of the water-dispersible resin in the ink is preferably 1 to 15% by weight, more preferably 2 to 7% by weight in terms of solid content.

(Antiseptic and antifungal agent)
Examples of the antiseptic / antifungal agent include sodium dehydroacetate, sodium sorbate, 2-pyridinethiol-1-oxide sodium, sodium benzoate, and sodium pentachlorophenol.
(Chelating reagent)
Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate, and the like.
(Rust inhibitor)
Examples of the rust preventive include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.
(Antioxidant)
Examples of the antioxidant include phenolic antioxidants (including hindered phenolic antioxidants), amine-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants.
(UV absorber)
Examples of the ultraviolet absorber include benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, salicylate ultraviolet absorbers, cyanoacrylate ultraviolet absorbers, and nickel complex ultraviolet absorbers.

Examples of the method for obtaining composite particles include the following methods [1] to [6].
[1] The pigment particles (B), liquid, subcritical or supercritical carbon dioxide and the monomer (a) are mixed, and the monomer (a) is impregnated in the pigment particles (B). By forming a composite particle (C1) in which the pigment particle (B) is coated with the polymer (A) by a polymerization reaction, the composite particle is removed by removing liquid, subcritical or supercritical carbon dioxide. Can be obtained.
[2] The pigment particles (B), liquid, subcritical or supercritical carbon dioxide, and a solution (L) in which the monomer (a) is dissolved in the solvent (S) are mixed, and the monomer The pigment particles (B) are impregnated with the pigment particles (B) and polymerized to form composite particles (C2) in which the pigment particles (B) are coated with the polymer (A). Composite particles can be obtained by removing carbon dioxide and the solvent (S) in a supercritical state.
[3] Pigment particles (B), liquid, subcritical or supercritical carbon dioxide and polymer (A) precursor (A0) are mixed, and the precursor (A0) is mixed with pigment particles (B). After forming the composite particles (C3) in which the pigment particles (B) are coated with the polymer (A) by impregnating them and reacting them, carbon dioxide in a liquid, subcritical or supercritical state is removed. Thus, composite particles can be obtained.
[4] Mixing pigment particles (B), liquid, subcritical or supercritical carbon dioxide, and a solution (L) in which a polymer (A) precursor (A0) is dissolved in a solvent (S). Then, the pigment particles (B) are impregnated with the precursor (A0) of the polymer (A) and subjected to a polymerization reaction, whereby the composite particles (C4) in which the pigment particles (B) are coated with the polymer (A) are obtained. After the formation, composite particles can be obtained by removing carbon dioxide and solvent (S) in a liquid, subcritical or supercritical state.
[5] The pigment particles (B), the penetrating solvent, and the monomer (a) are mixed, the pigment particles (B) are impregnated with the monomer (a), and the polymerization reaction is performed. After forming the composite particles (C5) in which B) is coated with the polymer (A), the composite particles can be obtained by removing the penetrating solvent.
[6] The pigment particles (B), the penetrating solvent, and the solution (L) in which the monomer (a) is dissolved in the solvent (S) are mixed, and the monomer (a) is mixed with the pigment particles (B). The composite particles (C6) in which the pigment particles (B) are coated with the polymer (A) are formed by impregnating the polymer particles with the polymer (A), and then the penetrating solvent and the solvent (S) are removed to remove the composite particles. Can be obtained.
[7] By mixing the pigment particles (B), the penetrating solvent, and the precursor (A0) of the polymer (A), the pigment particles (B) are impregnated with the precursor (A0), and reacted. After the composite particles (C7) in which the pigment particles (B) are coated with the polymer (A) are formed, the composite particles can be obtained by removing the penetrating solvent.
[8] The pigment particles (B), the penetrating solvent, and the solution (L) obtained by dissolving the precursor (A0) of the polymer (A) in the solvent (S) are mixed to obtain the precursor of the polymer (A). After the body (A0) is impregnated into the pigment particles (B) and subjected to a polymerization reaction, the composite particles (C8) in which the pigment particles (B) are coated with the polymer (A) are formed, and then the penetrating solvent and the solvent By removing (S), composite particles can be obtained.

<Method for producing ink composition>
The ink composition containing the pigment particles for ink or the composite particles for ink of the present invention is obtained by dispersing or dissolving the pigment particles of the present invention and, if necessary, other components in the medium (S), and further if necessary. Produced by stirring and mixing. The dispersion can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, etc., and stirring and mixing are performed by a stirrer using a normal stirring blade, a magnetic stirrer, a high-speed disperser, or the like. be able to. Moreover, it can disperse | distribute also by the dispersion method using the expansion energy of a compressive fluid. The compressible fluid is not particularly limited, and may be, for example, methane, ethylene, chlorofluorocarbon alternative, etc., but is preferably carbon dioxide from the viewpoint of safety and ease of handling, and more preferably liquid carbon dioxide, subcritical fluid Carbon dioxide or supercritical carbon dioxide is preferred. In addition, a compressive fluid means the fluid compressed by the pressure more than normal pressure at normal temperature.

  The ink composite particle or the ink composition containing the composite particle for ink of the present invention is used for applications such as offset printing ink, relief printing ink, gravure printing ink, silk printing ink, inkjet recording ink, and color filter. Can be used.

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited thereto.
In the following description, “parts” indicates parts by weight.

<Production Example 1> [Preparation of monomer solution (L-1)]
A monomer solution (L-1) was prepared by stirring 20 parts of acrylic acid, 7.8 parts of NaOH, and 20 parts of water in a beaker while cooling with an ice bath.

<Example 1>
In a pressure-resistant reaction vessel equipped with a stirring bar and a thermometer, 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) as an initiator and a primary volume average particle diameter (D50) of 90 nm An organic pigment Pigment Blue 15: 3 having a volume average particle size (D50) of 10 μm: 100 parts, charged up to 40% of the volume of the pressure vessel for reaction, sealed, and the air inside was replaced with carbon dioxide. L-1) 20 parts were charged, carbon dioxide was injected to 8 MPa, the mixture was stirred for 1 hour at 40 ° C. and impregnated with the monomer, and then attached to the lower part of the container while keeping the pressure and temperature constant. It discharged | emitted from the nozzle in the pressure | voltage resistant receiving tank, and it was measured with the particle size measuring device LB-550 by Horiba, Ltd. that the pigment had a particle size of 90 nm. Composite particles having an impregnated layer impregnated with the polymer (A-1) by charging again into a pressure vessel for reaction and polymerizing by stirring at 80 ° C. and 12 MPa for 2 hours and then removing carbon dioxide and water under reduced pressure. (C-1) was created. The volume average particle diameter was 92 nm. The average thickness of the impregnated layer was 10 nm.

<Example 2>
In a pressure-resistant vessel equipped with a stir bar and a thermometer, 0.3 part of 1,4-phenylenediamine, 1.6 parts of polyethylene glycol diglycidyl ether (number average molecular weight = 600), primary volume average particle diameter (D50 ) Is 90 nm, and 100 parts of organic pigment pigment blue 15: 3 having a volume average particle diameter (D50) of 10 μm is charged up to 40% of the volume of the pressure vessel for reaction, sealed, and the inside air is replaced with carbon dioxide. The pressure is reduced to 10 MPa by injecting carbon, and after stirring for 1 hour at 80 ° C. and impregnating the monomer with the pigment, the mixture is stirred and reacted for 3 hours at 12 MPa and 100 ° C. It was discharged and received from a nozzle attached to the pressure-resistant receiving tank. Composite particles (C-2) having an impregnated layer impregnated with the polymer (A-2) were prepared. The volume average particle diameter was 92 nm. The average thickness of the impregnated layer was 12 nm.

<Example 3>
In a pressure-resistant vessel for reaction equipped with a stir bar and a thermometer, 1.3 parts of isophorone diisocyanate and 1.4 parts of polyethylene glycol (number average molecular weight = 500) were mixed and reacted at 90 ° C. for 15 hours to give a precursor (A0 -1), after cooling to 25 ° C., 0.5 part of hydroxyethylmorpholine, an organic pigment pigment having a volume average particle diameter (D50) of 10 μm and a primary volume average particle diameter (D50) of 90 nm Blue 15: 3 100 parts were charged to 40% of the volume of the pressure vessel for reaction, sealed, the inside air was replaced with carbon dioxide, carbon dioxide was injected to 12 MPa, stirred at 40 ° C. for 1 hour, The precursor (A0-1) was impregnated into the pigment. After stirring and reacting for 15 hours, the pressure and temperature were kept constant and discharged from a nozzle attached to the bottom of the container into a pressure-resistant receiving tank. Composite particles (C-3) having an impregnated layer impregnated with the polymer (A-3) were prepared. The volume average particle diameter was 92 nm. The average thickness of the impregnated layer was 11 nm.

<Example 4>
In a pressure-resistant reaction vessel equipped with a stirring bar and a thermometer, 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) as an initiator and a primary volume average particle diameter (D50) of 50 nm An organic pigment Pigment Blue 15: 3 having a volume average particle diameter (D50) of 3 μm: 100 parts, charged to 40% of the volume of the pressure vessel for reaction, sealed, and the air inside was replaced with carbon dioxide. L-1) 20 parts are charged, carbon dioxide is injected to 8 MPa, and the mixture is stirred for 3 hours at 40 ° C. and impregnated with the monomer solution (L-1), and then the pressure and temperature are kept constant. While discharging from the nozzle attached to the lower part of the container into the pressure-resistant receiving tank, it was measured with a particle size measuring device LB-550 manufactured by Horiba, Ltd. that the pigment had a particle size of 51 nm. The composite particle having an impregnated layer impregnated with the polymer (A-4) is charged again into the pressure vessel for reaction, polymerized by stirring at 80 ° C. and 12 MPa for 2 hours and then depressurizing to remove carbon dioxide and water. (C-4) was created. The volume average particle size was 52 nm. The average thickness of the impregnated layer was 23 nm.

<Example 5>
In a pressure-resistant reaction vessel equipped with a stirring bar and a thermometer, 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) as an initiator and a primary volume average particle diameter (D50) of 90 nm Organic pigment pigment blue 15: 3 having a volume average particle size (D50) of 40 μm: 100 parts, charged to 40% of the volume of the pressure vessel for reaction, sealed, and the air inside was replaced with carbon dioxide. L-1) 20 parts were charged and carbon dioxide was injected to 7 MPa, and the mixture was stirred at 40 ° C. for 1 hour to impregnate the pigment with the monomer solution (L-1). After that, CO2 is depressurized from the upper part of the container and depressurized to 5 MPa, and while maintaining the pressure and temperature constant, it is discharged into the pressure-resistant receiving tank from the nozzle attached to the lower part of the container, and HORIBA Ltd. confirms that the pigment has a particle size of 490 nm. It measured with the particle size measuring apparatus LB-550. The composite particles having an impregnated layer impregnated with the polymer (A-5) are charged again in a pressure vessel for reaction, polymerized by stirring at 80 ° C. and 12 MPa for 2 hours, and then depressurized to remove carbon dioxide and water. (C-5) was prepared. The volume average particle diameter was 490 nm. The average thickness of the impregnated layer was 13 nm.

<Example 6>
In a pressure-resistant reaction vessel equipped with a stirring bar and a thermometer, 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) as an initiator and a primary volume average particle diameter (D50) of 90 nm Organic pigment pigment blue 15: 3 having a volume average particle size (D50) of 40 μm: 100 parts, charged to 40% of the volume of the pressure vessel for reaction, sealed, and the air inside was replaced with carbon dioxide. L-1) 20 parts were charged, carbon dioxide was injected to 6 MPa, and the mixture was stirred at 20 ° C. for 0.1 hour to impregnate the pigment with the monomer solution (L-1). Thereafter, the temperature is raised to 40 ° C., and CO 2 is depressurized from the upper part of the container to a pressure of 5 MPa, and the pressure and temperature are kept constant, and then released from the nozzle attached to the lower part of the container into the pressure-resistant receiving tank. This was measured with a particle size measuring device LB-550 manufactured by Horiba. The composite particles having an impregnated layer impregnated with the polymer (A-6) by charging again into a pressure vessel for reaction and polymerizing by stirring at 80 ° C. and 12 MPa for 2 hours and then removing carbon dioxide and water by reducing the pressure. (C-6) was prepared. The volume average particle diameter was 490 nm. The average thickness of the impregnated layer was 6 nm.

<Example 7>
In a pressure-resistant reaction vessel equipped with a stirring bar and a thermometer, 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) as an initiator and a primary volume average particle diameter (D50) of 90 nm An organic pigment Pigment Blue 15: 3 having a volume average particle size (D50) of 10 μm: 100 parts, charged up to 40% of the volume of the pressure vessel for reaction, sealed, and the air inside was replaced with carbon dioxide. L-1) Charge 20 parts, stir at 7 MPa and 40 ° C. for 1 hour to impregnate the monomer with the pigment, remove carbon dioxide in the tank from the nozzle at the top of the container, and add 900 parts of acetone to the contents. In addition, dispersion was performed for 3 hours using zirconia beads (0.4 mm in diameter) media with a dyno mill (Willie & Bacofen Multi-Lab type), and it was manufactured by Horiba that the pigment had a particle size of 95 nm. Measured in manufacturing particle size measuring apparatus LB-550. Composite particles having an impregnated layer impregnated with the polymer (A-7) by charging again into a pressure vessel for reaction, stirring and polymerizing at 80 ° C. and 12 MPa for 2 hours, and then removing carbon dioxide and water by reducing the pressure. (C-7) was prepared. The volume average particle diameter was 97 nm. The average thickness of the impregnated layer was 10 nm.

<Example 8>
Dynomill (Willie & Bacofen Multi-Lab type), 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) as an initiator, primary volume average particle diameter (D50) of 190 nm Organic pigment pigment blue 15: 3 100 parts having a volume average particle diameter (D50) of 10 μm, monomer parts (L-1) 20 parts, acetone 900 parts, zirconia beads (diameter 0.4 mm) are charged at 5 ° C. The dispersion was performed for 100 hours, and it was measured with a particle size measuring device LB-550 manufactured by Horiba, Ltd. that the pigment had a particle size of 195 nm. The reaction mixture was charged again in a pressure vessel for reaction, stirred and polymerized at 80 ° C. for 2 hours, and then reduced in pressure to remove acetone and water, whereby composite particles having an impregnated layer impregnated with the polymer (A-8) (C— 8) was created. The volume average particle diameter was 196 nm. The average thickness of the impregnated layer was 1 nm.

<Example 9>
In a pressure-resistant reaction vessel equipped with a stirring bar and a thermometer, 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) as an initiator and a primary volume average particle diameter (D50) of 90 nm An organic pigment Pigment Blue 15: 3 having a volume average particle size (D50) of 10 μm: 100 parts, charged to 40% of the volume of the pressure vessel for reaction, sealed and removed by reducing the internal air, and then the monomer solution ( L-1) 20 parts were charged, acetone was injected to 50 MPa, the mixture was stirred at 25 ° C. for 1 hour and impregnated with the monomer, and then discharged from the nozzle attached to the bottom of the container into the pressure-resistant receiving tank. . The obtained contents were dispersed for 3 hours using a zirconia bead (0.4 mm diameter) medium in a dyno mill (Willie & Bacofen Multi-Lab type), and the pigment had a particle size of 90 nm. The particle size was measured with a particle size measuring apparatus LB-550 manufactured by Horiba. The reaction mixture was again charged into a pressure vessel for reaction, stirred and polymerized at 80 ° C. for 2 hours, and then reduced in pressure to remove acetone and water, whereby composite particles having an impregnated layer impregnated with the polymer (A-9) (C— 9) was created. The volume average particle diameter was 93 nm. The average thickness of the impregnated layer was 2 nm.

<Example 10>
In a pressure-resistant reaction vessel equipped with a stirring bar and a thermometer, 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) as an initiator and a primary volume average particle diameter (D50) of 90 nm An organic pigment Pigment Blue 15: 3 having a volume average particle size (D50) of 10 μm: 100 parts, charged up to 40% of the volume of the pressure vessel for reaction, sealed, and the air inside was replaced with carbon dioxide. L-1) Charge 20 parts, press-fit carbon dioxide to 7 MPa, stir at 20 ° C. for 1 hour to impregnate the monomer with the pigment, then discharge into the pressure receiving tank from the nozzle attached to the bottom of the container Then, it was measured with a particle size measuring device LB-550 manufactured by Horiba, Ltd. that the pigment had a particle size of 90 nm. The composite particles having an impregnated layer impregnated with the polymer (A-10) are charged again in a pressure vessel for reaction, polymerized by stirring at 80 ° C. and 12 MPa for 2 hours, and then depressurized to remove carbon dioxide and water. (C-10) was prepared. The volume average particle diameter was 92 nm. The average thickness of the impregnated layer was 7 nm.

<Example 11>
In a pressure vessel for reaction equipped with a stir bar and a thermometer, 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) as an initiator and Azisper PB822 (manufactured by Ajinomoto Fine Techno Co., Ltd.) as a dispersant 10 parts by weight average molecular weight 7600), 100 parts by weight of organic pigment Pigment Blue 15: 3 having a volume average particle diameter (D50) of 40 μm having a primary volume average particle diameter (D50) of 90 nm, and 40 parts by volume of the pressure vessel for reaction. %, And after sealing and replacing the internal air with carbon dioxide, 20 parts of the monomer solution (L-1) was charged, and the pressure was 6 MPa by injecting carbon dioxide, followed by stirring at 20 ° C. for 0.1 hour. The pigment solution was impregnated with the monomer solution (L-1). Thereafter, the temperature is raised to 40 ° C., and CO2 is depressurized from the upper part of the container to a pressure of 5 MPa, and the pressure and temperature are kept constant, and then released from the nozzle attached to the lower part of the container into the pressure-resistant receiving tank. This was measured with a particle size measuring device LB-550 manufactured by Horiba. The composite particle having an impregnated layer impregnated with the polymer (A-11) is charged again into the pressure vessel for reaction, polymerized by stirring at 80 ° C. and 12 MPa for 2 hours and then depressurizing to remove carbon dioxide and water. (C-11) was created. The volume average particle size was 95 nm. The average thickness of the impregnated layer was 7 nm.

<Comparative Example 1>
Organic pigment Pigment Blue 15: 3 100 parts with a primary volume average particle diameter (D50) of 90 nm and particle size 10 μm, monomer solution (L-1) 20 parts, Solsperse 28000 (Nippon Lubrizol Co., Ltd.) as a dispersant 5) 5 parts was crushed with a sand grinder for 12 hours to obtain a dispersion. In a pressure vessel equipped with a stir bar and a thermometer, 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) and 400 parts of water are introduced as a dispersion and an initiator, and the air is carbon dioxide. After the replacement, the temperature was raised to 80 ° C., and the mixture was stirred for 2 hours at normal pressure for polymerization. After stirring, composite particles (C′-1) coated with the polymer (A′-1) were removed by removing water. The volume average particle size was 95 nm. The average thickness of the impregnated layer was 0 nm.

<Comparative Example 2>
Primary volume average particle diameter (D50) Organic pigment Pigment Blue 15: 3 100 parts with a particle diameter of 10 μm having a diameter of 90 μm and monomer part (L-1) 20 parts, 4-methylphenylethyl vinyl ether (A block as a dispersant) ), 2- (2-methoxyethyl) ethyl vinyl ether (B block) and 4- (2-vinyloxy) ethoxybenzoic acid (C block) as constituent monomers (polymerization ratio (molar ratio) ) A: B: C = 98: 90: 14) (Mn = 27,200, Mw / Mn = 1.36) 5 parts were crushed with a sand grinder for 12 hours to obtain a dispersion. Into a vessel equipped with a stir bar and a thermometer, 0.5 part of 2,2′-azobis (2,4-dimethylvaleronitrile) and 400 parts of water are introduced as a dispersion and an initiator, and the air is replaced with carbon dioxide. Thereafter, the temperature was raised to 80 ° C., and polymerization was carried out by stirring for 2 hours at normal pressure. Stirrer and water were removed to obtain composite particles (C′-2) coated with polymer (A′-2). The volume average particle diameter was 92 nm. The average thickness of the impregnated layer was 0 nm.

<Comparative Example 3>
A container equipped with a stir bar and a thermometer was charged with 0.3 part of aminopyridine and 1.6 parts of polyethylene glycol diglycidyl ether (number average molecular weight = 600) and stirred at 100 ° C. for 3 hours. ) Was produced.
Organic pigment pigment blue 15: 3 having a primary volume average particle size (D50) of 90 nm and a particle size of 10 μm: 100 parts, monomer solution (L-1) 20 parts, (PD-1) 5 parts, acetone 380 The part was crushed with a sand grinder for 12 hours to obtain a dispersion. The dispersion was charged into a vessel equipped with a stir bar and a thermometer, heated to 80 ° C., stirred for 2 hours at normal pressure, and polymerized. Acetone and water were removed from the dispersion to prepare composite particles (C′-3) coated with the polymer (A′-3). The volume average particle size was 90 nm. The average thickness of the impregnated layer was 0 nm.

<Comparative example 4>
A pressure vessel equipped with a stir bar and a thermometer is charged with 1.3 parts of isophorone diisocyanate and 0.6 parts of polyethylene glycol (number average molecular weight = 500) and stirred at 90 ° C. for 5 hours to prepare a dispersant (PD-2). did.
Organic pigment Pigment Blue 15: 3 having a primary volume average particle size (D50) of 90 nm and a particle size of 10 μm: 100 parts, monomer solution (L-1) 20 parts, (PD-2) 5 parts, acetone 380 The part was crushed with a sand grinder for 12 hours to obtain a dispersion. The dispersion was charged into a vessel equipped with a stir bar and a thermometer, heated to 80 ° C., stirred for 2 hours at normal pressure, and polymerized. Acetone and water were removed from the dispersion to prepare composite particles (C′-4) coated with the polymer (A′-4). The volume average particle size was 90 nm. The average thickness of the impregnated layer was 0 nm.

The dispersion stability was evaluated by the following evaluation method. The results are shown in Table 1.
<Water dispersion stability test>
1 part of each of the particles (C-1) to (C-11) and the comparative particles (C′-1) to (C′-4) is dispersed in 20 parts of water by ultrasonic treatment for 3 minutes, and dispersed. A liquid was created.
Disperse the PP screw test tube [tube diameter 12 mm, height 120 mm, manufactured by ASONE Co., Ltd.] 5 g each of the dispersion, disperse by ultrasonic treatment for 3 minutes, and allow to stand at 40 ° C. for 6 hours. The particle size was measured with a particle size measuring device LB-550 manufactured by Horiba.
Evaluation of dispersion stability test A: No settling of particles was observed after the test, and the change in particle size before and after the test was less than 5%.
○: No settling of particles was observed after the test, and the change in particle size before and after the test was 5% or more and less than 10%.
Δ: Settling of particles after the test is observed, but the change in the particle size before and after the test is less than 10%.
X: Settling of particles after the test was observed, and the change in the particle size before and after the test was 10% or more.

In addition, in order to clarify the effect of the adhesion of the coating substance to the pigment particles, 5 g of each dispersion was charged in a PP screw test tube (tube diameter: 12 mm, height: 120 mm, manufactured by ASONE Co., Ltd.). The dispersion was shaken for 24 hours with an in vitro shaker wave SIslim, and the water dispersion stability under shaking was evaluated from the appearance of the dispersion after standing at 40 ° C. for 6 hours.
Water dispersion stability under shaking A: No settling of particles was observed after the test, and the change in particle size before and after the test was less than 5%.
○: No settling of particles was observed after the test, and the change in particle size before and after the test was 5% or more and less than 10%.
Δ: Settling of particles after the test is observed, but the change in the particle size before and after the test is less than 10%.
X: Settling of particles after the test was observed, and the change in the particle size before and after the test was 10% or more.

  Regarding the foamability of the aqueous dispersion, 10 ml each of the dispersion was added to a 100 ml graduated cylinder containing a glass tube having a tip diameter of 0.9 mm, and the temperature was controlled in a thermostatic bath at 25 ° C. for 1 hour. Nitrogen was blown at a constant pressure, and the blowing was stopped either when the foam reached 100 ml or at one minute, and the foam height (ml) after 30 seconds was visually confirmed.

<Solvent dispersion stability test>
1 part of each of the particles (C-1) to (C-11) and the comparative particles (C′-1) to (C′-4) is dispersed in 20 parts of methyl ethyl ketone by ultrasonic treatment for 3 minutes. A liquid was created. Disperse the PP screw test tube [tube diameter 12 mm, height 120 mm, manufactured by ASONE Co., Ltd.] 5 g each of the dispersion, disperse by ultrasonic treatment for 3 minutes, and allow to stand at 40 ° C. for 6 hours. The particle size was measured with a particle size measuring device LB-550 manufactured by Horiba.
Solvent dispersion stability test evaluation A: No settling of particles was observed after the test, and the change in particle size before and after the test was less than 5%.
○: No settling of particles was observed after the test, and the change in particle size before and after the test was 5% or more and less than 10%.
Δ: Settling of particles after the test is observed, but the change in the particle size before and after the test is less than 10%.
X: Settling of particles after the test was observed, and the change in the particle size before and after the test was 10% or more.

In addition, in order to clarify the effect of the adhesion of the coating substance to the pigment particles, 5 g each of the dispersion was added to a PP screw test tube (tube diameter: 12 mm, height: 120 mm, manufactured by ASONE Co., Ltd.), and a table made by TAITEC The dispersion stability of the solvent under shaking was evaluated from the appearance of the dispersion liquid after shaking for 24 hours in a small shaker, in vitro shaker wave SIslim, and standing at 40 ° C. for 6 hours.
Dispersion stability under shaking A: No settling of particles was observed after the test, and the change in particle size before and after the test was less than 5%.
○: No settling of particles was observed after the test, and the change in particle size before and after the test was 5% or more and less than 10%.
Δ: Settling of particles after the test is observed, but the change in the particle size before and after the test is less than 10%.
X: Settling of particles after the test was observed, and the change in the particle size before and after the test was 10% or more.

<Monomer dispersion stability test>
One part of each of the particles (C-1) to (C-11) and the comparative particles (C′-1) to (C′-4) is dispersed in 20 parts of methyl methacrylate by ultrasonic treatment for 3 minutes. A dispersion was created. Disperse the PP screw test tube [tube diameter 12 mm, height 120 mm, manufactured by ASONE Co., Ltd.] 5 g each of the dispersion, disperse by ultrasonic treatment for 3 minutes, and allow to stand at 40 ° C. for 6 hours. The particle size was measured with a particle size measuring device LB-550 manufactured by Horiba.
Solvent dispersion stability test evaluation A: No settling of particles was observed after the test, and the change in particle size before and after the test was less than 5%.
○: No settling of particles was observed after the test, and the change in particle size before and after the test was 5% or more and less than 10%.
Δ: Settling of particles after the test is observed, but the change in the particle size before and after the test is less than 10%.
X: Settling of particles after the test was observed, and the change in the particle size before and after the test was 10% or more.

In addition, in order to clarify the effect of the adhesion of the coating substance to the pigment particles, 5 g each of the dispersion was added to a PP screw test tube (tube diameter: 12 mm, height: 120 mm, manufactured by ASONE Co., Ltd.), and a table made by TAITEC The monomer solvent dispersion stability under shaking was evaluated from the appearance of the dispersion liquid after shaking for 24 hours with a small shaker in vitro shaker wave SIslim and standing at 40 ° C. for 6 hours.
Dispersion stability under shaking A: No settling of particles was observed after the test, and the change in particle size before and after the test was less than 5%.
○: No settling of particles was observed after the test, and the change in particle size before and after the test was 5% or more and less than 10%.
Δ: Settling of particles after the test is observed, but the change in the particle size before and after the test is less than 10%.
X: Settling of particles after the test was observed, and the change in the particle size before and after the test was 10% or more.
[Creation of ink composition]
30 parts of each of the above composite particles (C-1) to (C-11) and composite particles (C′-1) to (C′-4) and 1 part of Olfine E1010 (manufactured by Nissin Chemical Industry Co., Ltd.) 169 parts of distilled water was mixed and dispersed for 1 hour using an ultrasonic disperser to prepare a pigment dispersion containing 15% of Organic Pigment Pigment Blue 15: 3 pigment.
50 parts of the obtained pigment dispersion, 10 parts of glycerin, 10 parts of triethylene glycol, and 30 parts of water were stirred and mixed uniformly to obtain ink compositions (P-1) to (P-11) and ( P′-1) to (P′-4) were prepared. The particle size of the obtained pigment particles was measured with a particle size measuring device LB-550 manufactured by Horiba.

The print density was evaluated by the following evaluation method. The results are shown in Table 2.
<Dispersion stability test of ink composition>
Each of the ink compositions (P-1) to (P-11) and (P′-1) to (P′-4) is applied to a PP screw test tube [tube diameter: 12 mm, height: 120 mm, manufactured by ASONE Corporation]. 5 g of each dispersion was charged and dispersed by treating with ultrasonic waves for 3 minutes, and the appearance of the ink composition after being allowed to stand at 40 ° C. for 6 hours was evaluated, and the particle size was measured by LB-550, a particle size measuring device manufactured by Horiba. Measured with
Solvent dispersion stability test evaluation A: No settling of particles was observed after the test, and the change in particle size before and after the test was less than 5%.
○: No settling of particles was observed after the test, and the change in particle size before and after the test was 5% or more and less than 10%.
Δ: Settling of particles after the test is observed, but the change in the particle size before and after the test is less than 10%.
X: Settling of particles after the test was observed, and the change in the particle size before and after the test was 10% or more.

In addition, in order to clarify the effect of the adhesion of the coating substance to the pigment particles, 5 g each of the dispersion was added to a PP screw test tube (tube diameter: 12 mm, height: 120 mm, manufactured by ASONE Co., Ltd.), and a table made by TAITEC The dispersion stability of the ink composition under shaking was evaluated from the appearance of the dispersion after shaking for 24 hours with a small shaker, in vitro shaker wave SIslim, and standing at 40 ° C. for 6 hours.
Dispersion stability under shaking A: No settling of particles was observed after the test, and the change in particle size before and after the test was less than 5%.
○: No settling of particles was observed after the test, and the change in particle size before and after the test was 5% or more and less than 10%.
Δ: Settling of particles after the test is observed, but the change in the particle size before and after the test is less than 10%.
X: Settling of particles after the test was observed, and the change in the particle size before and after the test was 10% or more.
[Image recording and evaluation]
Image density evaluation was performed on the inkjet inks prepared in the above-described examples and comparative examples. The results are shown in Table 1. The evaluation of the print density was performed using an image output using photo glossy paper (PM photo paper (KA420PSK) manufactured by Seiko Epson Corporation) with an inkjet printer (PM-700C manufactured by Seiko Epson Corporation). .

<Print density>
The print density at a print density of 100% is measured using a reflection densitometer (X-Rite 310TR). The print density is 1.05 or more, A is 0.95 or more and less than 1.05, B is 0. The case of less than 95 was defined as C and evaluated in three stages.

  As shown in Table 1, the composite particles for inks described in the examples are superior in dispersion stability as compared with the composite particles of the comparative example. The ink composition containing the composite particles for ink described in the examples is excellent in both dispersion stability and print density, while the ink composition of the comparative example is inferior in at least one of dispersion stability and print density. It is clear.

  Since the pigment particles of the present invention have a mixed layer with a coating substance, particles having excellent dispersion stability can be obtained without the removal of the dispersant as compared with pigment particles dispersed with a conventional dispersant.

Claims (7)

  Composite particles comprising a polymer (A) and pigment particles (B), wherein the surface of the pigment particles (B) is coated with a coating layer containing the polymer (A), and the surface of the pigment particles (B) Composite particles for ink having an impregnated layer impregnated with the polymer (A) on the inside thereof, wherein the average thickness of the impregnated layer is 0.1 to 50% of the volume average particle size of the composite particles.   The composite particle for ink according to claim 1, wherein the volume average particle diameter is 10 nm or more and less than 500 nm.   An ink composition comprising the composite particles for ink according to claim 1.   The pigment particles (B), liquid, subcritical or supercritical carbon dioxide, and the monomer (a) are mixed, the monomer particles (B) are impregnated in the pigment particle (B), and a polymerization reaction is performed. After forming the composite particles (C1) in which the pigment particles (B) are coated with the polymer (A), the composite particles are obtained by removing carbon dioxide in a liquid, subcritical or supercritical state. The manufacturing method of the composite particle for inks of Claim 1 or 2 containing these.   The pigment particles (B), liquid, subcritical or supercritical carbon dioxide, and a solution (L) in which the monomer (a) is dissolved in the solvent (S) are mixed to obtain the monomer (a). After the pigment particles (B) are impregnated and polymerized to form composite particles (C2) in which the pigment particles (B) are coated with the polymer (A), the liquid, subcritical or supercritical state is formed. The method for producing composite particles for ink according to claim 1, comprising a step of obtaining composite particles by removing carbon dioxide and the solvent (S).   The pigment particles (B), liquid carbon dioxide in a subcritical or supercritical state, and the precursor (A0) of the polymer (A) are mixed, and the pigment particles (B) are impregnated with the precursor (A0). Then, the composite particles (C3) in which the pigment particles (B) are coated with the polymer (A) are formed by the reaction, and then the carbon particles in the liquid, subcritical or supercritical state are removed to remove the composite particles. The manufacturing method of the composite particle for ink of Claim 1 or 2 including the process of obtaining.   The manufacturing method of the ink composition using the composite particle for ink obtained by the manufacturing method in any one of Claims 4-6.