JP2009242566A - Inkjet recording ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide pigment ink for an inkjet printer which uses a general-purpose pigment, avoids reaggregation of the pigment in an oily medium consisting mainly of a solvent and/or a photopolymerizable compound, and is excellent in storage stability and dispersion stability. <P>SOLUTION: The inkjet recording ink comprises a pigment dispersant which is soluble in a diluent, a diluent which can dissolve the pigment dispersant, and a colorant, wherein the colorant is a modified pigment (D) having on a pigment (A) surface a polymer (P) obtained by polymerizing a polymer (B) containing a polymerizable unsaturated group which is soluble in a nonaqueous solvent and at least one polymerizable unsaturated monomer (C) which is soluble in a nonaqueous solvent and becomes insoluble or slightly soluble after polymerization. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inkjet recording ink using a modified pigment as a colorant.

  Conventionally, water-based dye inks using dyes as coloring materials have been used for ink jet recording inks. Aqueous dye ink has many advantages such as excellent storage stability, hardly clogging the nozzles of an ink jet printer, and the printed matter obtained has excellent gloss. However, it has been pointed out that there are defects derived from dyes such as inability to store printed matter for a long time due to poor weather resistance, and poor water resistance and light resistance. In recent years, it has been pointed out that weather resistance, water resistance and light resistance are poor. Development of inks for ink jet recording using excellent pigments is in progress.

Since pigment-based inks are insoluble in the medium, they generally have problems such as poor dispersion stability and easy clogging at the nozzle portion.
On the other hand, an ink in which a pigment is dispersed in a non-polar insulating solvent (hereinafter referred to as an oil-based pigment ink) has less blur due to good absorption of the solvent into paper, and the recorded image has good water resistance. There are advantages. However, since the dispersion stability is still poor, the nozzle portion still has problems such as being easily clogged. Furthermore, since the pigment itself does not have a fixing ability with respect to the recording paper, it has a great drawback that it has poor scratch resistance.

Furthermore, in recent years, high-quality photographic quality has been achieved with a general ink jet printer using aqueous dye ink, and even with pigment ink, the pigment is made as fine as possible in order to increase color development and transparency, and its dispersed state Is required to be kept stable.
However, the finer the pigment, the more the primary pigment particles are crushed at the same time. Furthermore, the surface energy increases and the agglomeration energy increases, so that reaggregation is likely to occur. Detrimental effects such as loss of stability occur.

  In order to improve these, it has been proposed to coat pigment particles with a resin that is insoluble or semi-soluble in a non-aqueous solvent. For example, Patent Document 1 describes an oil-based ink in which a pigment is coated with a resin by a microcapsule method or the like. Further, in Patent Document 2, a coloring component fine particle obtained by dispersing a coloring component obtained by surface-treating a colorant in a non-aqueous solvent in a fine particle form in the non-aqueous solvent is used as a seed particle, and a monomer and a polymer main chain are included. An oil-based ink composition for ink jet printers containing colored resin particles obtained by adding a dispersion stabilizer consisting of a polymer partially crosslinked and soluble in a non-aqueous solvent, and dispersion polymerizing in the presence of a polymerization initiator. Are listed.

However, in the method described in Patent Document 1, it is difficult to uniformly disperse the pigment-encapsulating resin particles, and the dispersion stability is not sufficient.
The method described in Patent Document 2 may not be effective at all depending on the pigment used or the surface treatment method of the pigment (for example, see Comparative Examples 1 to 3 in Patent Document 2), that is, a general-purpose method. It can not be said.

JP-A-4-25574 JP 2004-285170 A

  An object of the present invention is an oil-based medium using a general-purpose pigment and mainly composed of a solvent and / or a photopolymerizable compound, and having excellent storage stability and dispersion stability without reaggregation of the pigment. It is to provide a pigment ink.

  The inventor of the present invention previously invented (Japanese Patent Application No. 2006-267283), a polymer containing a polymerizable unsaturated group soluble in a non-aqueous solvent and a non-aqueous solvent and polymerized on the pigment surface. A pigment characterized by having a polymer obtained by copolymerizing with at least one polymerizable unsaturated monomer that becomes insoluble or hardly soluble later, when dispersed as an oil-based pigment ink for inkjet printers The present inventors have found that it is excellent in stability and have completed the present invention.

  That is, the present invention includes a pigment dispersant that is soluble in an organic solvent, a solvent that can dissolve the pigment dispersant, and a colorant. The colorant is soluble in a non-aqueous solvent on the surface of the pigment (A). A polymer (B) containing a polymerizable unsaturated group and at least one polymerizable unsaturated monomer (C) that is soluble in a non-aqueous solvent and becomes insoluble or hardly soluble after polymerization An ink for inkjet recording containing the modified pigment (D) having the polymer (P) obtained by the above is provided.

  The present invention also includes a pigment dispersant that can be dissolved in an organic solvent, a solvent that can dissolve the pigment dispersant, and a colorant. The colorant may be a pigment (A), a non-aqueous solvent, or a non-aqueous solvent. At least one polymerizable unsaturated monomer (C) that is soluble in the non-aqueous solvent and insoluble or hardly soluble after polymerization in the presence of the polymer (B) containing a soluble polymerizable unsaturated group An ink for ink jet recording containing a modified pigment (D) for polymerizing the polymer is provided.

  According to the present invention, a pigment ink for an ink jet printer which uses a general-purpose pigment and is an oil-based medium mainly composed of a solvent and / or a photopolymerizable compound and has excellent storage stability and dispersion stability without reaggregation of the pigment. Is obtained.

(Modified pigment (D))
The modified pigment (D) used as a colorant in the present invention is a general-purpose pigment (A), a non-aqueous solvent, and a polymer (B) containing a polymerizable unsaturated group soluble in the non-aqueous solvent. The polymer can be obtained by so-called in-situ polymerization in which at least one polymerizable unsaturated monomer (C) that is soluble in the non-aqueous solvent and becomes insoluble or hardly soluble after polymerization is polymerized.
Conventionally, the in-situ polymerization method has been considered to require a polymerization field in which a pigment is finely and stably dispersed in a dispersion stabilizer. However, in the present invention, a polymerizable unsaturated group soluble in a non-aqueous solvent is added. The interface between the pigment (A) formed by wetting the surface of the pigment (A) with the polymer (B) contained and the polymer (B) containing a polymerizable unsaturated group soluble in a non-aqueous solvent is polymerized. It is not essential that the pigment is finely and stably dispersed in the dispersion stabilizer, and therefore surface treatment of the pigment to form a finely dispersed state is not always necessary, and a wide range of It can be applied to various types of pigments.

(Modified pigment (D) Pigment (A))
The pigment (A) used in the present invention is at least one pigment selected from known and commonly used organic pigments or inorganic pigments. In addition, the present invention can be applied to either an untreated pigment or a treated pigment.

  Examples of the pigment (A) used for the preparation of the modified pigment (D) include inorganic pigments such as barium sulfate, lead sulfate, titanium oxide, yellow lead, bengara, chromium oxide, and carbon black, anthraquinone pigments, perylene pigments, and disazo pigments. Examples thereof include pigments, phthalocyanine pigments, isoindoline pigments, dioxazine pigments, quinacridone pigments, perinone pigments, and benzimidazolone pigments. These can be used alone or in combination.

  As the black pigment, it is preferable to use carbon black such as furnace black, lamp black, acetylene black, channel black, etc., which has excellent light resistance and high hiding power. Specifically, for example, Raven 7000, Raven 5750, Raven 5250, Raven 5000 Ultra (ULTRA) II, Raven 3500, Raven 2500 Ultra, Raven 2000, Raven 1500, Raven 1255, Raven 1250, Raven 1200, Raven 1190 Ultra II, Raven 1170, Raven 1080 Ultra, Raven 1060 Ultra, Raven 790 Ultra, Raven 780 Ultra, Raven 760 Ultra (from Colombian Carbon), Regal 400R, Regal 330R, Legal 660R, Mogul (Mogul) L, Monarch 700, Monarch 800, Monarch 880, Monarch 9 0, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400 (manufactured by Cabot), Color Black FW1, Color Black FW2, Color Black FW2V, Color Black 18, Color Black FW200, Color Black S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140U, Printex 140V, Special Black 6, Special Black 5, Special Black 4A, Special Black 4 (above, manufactured by Degussa), No . 25, no. 33, no. 40, no. 45, no. 45L, no. 47, No 52, No. 900, no. 960, no. 2300, MCF-88, MA600, MA7, MA8, MA100 (manufactured by Mitsubishi Chemical Corporation), and the like.

Furthermore, among the representative organic pigments of cyan, magenta, and yellow, which are the three primary colors, pigments that can be suitably used in the present invention are exemplified below.
Examples of cyan pigments 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: 1, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 6, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. Pigment blue 60, and the like.

  Examples of magenta pigments 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, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57, 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 184, C.I. I. Pigment red 202, and the like.

  Examples of yellow pigments 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 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, and the like.

  As for the particle diameter of the pigment, the primary particle diameter is preferably in the range of 1 to 500 nm, and more preferably in the range of 20 to 200 nm. The particle diameter of the pigment after being dispersed in the medium is preferably in the range of 10 to 300 nm, and more preferably in the range of 50 to 150 nm. The primary particle diameter of the pigment can be measured by an electron microscope, a gas or solute adsorption method, an air flow method, an X-ray small angle scattering method, and the like. The pigment particle diameter after dispersion can be measured by a known and common centrifugal sedimentation method, laser diffraction method (light scattering method), ESA method, capillary method, electron microscope method and the like. Preferable is measurement by Microtrac UPA using a dynamic light scattering method.

  In the present invention, an organic pigment is particularly preferable because the effects of the present invention can be further exhibited.

(Modified pigment (D) Non-aqueous solvent)
The non-aqueous solvent used in the present invention is an organic solvent in which an aliphatic and / or alicyclic hydrocarbon solvent is essential. Examples of the aliphatic and / or alicyclic hydrocarbon solvents include n-hexane, n-heptane, “Loose” or “Mineral Split EC” manufactured by Shell Chemicals, and “Isopar C” manufactured by ExxonMobil Chemical. , “Isopar E”, “Isopar G”, “Isopar H”, “Isopar L”, “Isopar M”, “Naphtha 3”, “Naphtha 5” or “Naphtha 6”, products of Idemitsu Petrochemical Co., Ltd. "Solvent 7", "IP Solvent 1016", "IP Solvent 1620", "IP Solvent 2028" or "IP Solvent 2835", Japan Energy's "Whitesol" Maruzen Petrochemical's "Marcazole" 8 ”,“ AF Solvent No. 4 ”,“ AF Solvent ”by Nippon Oil Corporation Cement No. 5 "," AF Solvent No. 6 "and" AF Solvent No. 7 ", and the like.

Moreover, you may mix and use another organic solvent in the range which does not impair the effect of this invention. Specific examples of such organic solvents include “Swazole 100 or 150” manufactured by Maruzen Petrochemical Co., Ltd., aromatic hydrocarbon solvents such as toluene or xylene; methyl acetate, ethyl acetate, acetic acid- esters such as n-butyl or amyl acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone or cyclohexanone; or such as methanol, ethanol, n-propanol, i-propanol or n-butanol Examples include alcohols.
When mixed and used, the amount of the aliphatic and / or alicyclic hydrocarbon solvent used is preferably 50% by mass or more, and more preferably 60% by mass or more.

(Modified pigment (D) Polymer (B) containing polymerizable unsaturated group soluble in non-aqueous solvent)
Specifically, the polymer (B) containing a polymerizable unsaturated group soluble in the non-aqueous solvent used in the present invention is:
A polymer in which a polymerizable unsaturated group is introduced into a copolymer of a polymerizable unsaturated monomer mainly composed of an alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms,
Or the macromonomer etc. which consist of the copolymer of the polymerizable unsaturated monomer which has as a main component the alkyl (meth) acrylate which has a C4 or more alkyl group are mentioned.

Examples of the alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms include n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meta ) Acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like.
Examples of polymerizable unsaturated monomers other than alkyl (meth) acrylates include aromatic vinyl monomers such as styrene, α-methylstyrene, pt-butylstyrene or vinyltoluene, benzyl ( (Meth) acrylate, dimethylamino (meth) acrylate, diethylamino (meth) acrylate, (meth) acrylates such as dibromopropyl (meth) acrylate or tribromophenyl (meth) acrylate, maleic acid, fumaric acid or itaconic acid, etc. And diesters of unsaturated dicarboxylic acids and monohydric alcohols, vinyl esters such as vinyl benzoate, “Veoba” (vinyl ester manufactured by Shell of the Netherlands), and the like, and the above alkyl (meth) acrylates Can be used together with copolymerization That.
A single polymer of a polymerizable unsaturated group-containing monomer that can be used other than these alkyl (meth) acrylates has low solubility in the non-aqueous medium, so it is used as an alkyl (meth) acrylate and a random polymer. It is preferred that When the copolymerization is carried out in the form of a block or a graft, the solubility in the non-aqueous medium is remarkably lowered, which is not preferable.

  These polymerizable unsaturated monomers may be used alone or in combination of two or more. Of these, the use of linear or branched alkyl (meth) acrylates having 4 to 12 carbon atoms such as n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl methacrylate and the like is particularly preferable.

  A copolymer of a polymerizable unsaturated monomer having an alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms as a main component is obtained by polymerizing the polymerizable unsaturated monomer by a conventional method. can get.

By introducing a polymerizable unsaturated group into the copolymer of a polymerizable unsaturated monomer mainly comprising an alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms, polymerizable unsaturated A polymer (B) containing groups is obtained.
As a method for introducing a polymerizable unsaturated group, for example, a carboxyl group-containing polymerizable monomer such as acrylic acid or methacrylic acid or an amino group such as dimethylaminoethyl methacrylate or dimethylaminopropylacrylamide is previously used as the copolymer component. A polymerizable monomer is blended and copolymerized to obtain the copolymer having a carboxyl group or an amino group, and then having the carboxyl group or amino group, a glycidyl group such as glycidyl methacrylate, and a polymerizable unsaturated group. A method of reacting monomers,
A hydroxyl group-containing monomer such as 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate is previously blended and copolymerized as the copolymer component to obtain the copolymer having a hydroxyl group. Next, the hydroxyl group and isocyanate ethyl methacrylate are obtained. A method of reacting a monomer having a polymerizable unsaturated group with an isocyanate group such as
During polymerization, thioglycolic acid is used as a chain transfer agent to introduce a carboxyl group at the end of the copolymer, and a monomer having a glycidyl group such as glycidyl methacrylate and a polymerizable unsaturated group is added to the carboxyl group. How to react,
As a polymerization initiator, a carboxyl group-containing azo initiator such as azobiscyanopentanoic acid is used to introduce a carboxyl group into the copolymer, and a glycidyl group such as glycidyl methacrylate and a polymerizable unsaturated group are introduced into the carboxyl group. And the like. Among them, a carboxyl group-containing monomer such as acrylic acid or methacrylic acid or an amino group-containing monomer such as dimethylaminoethyl methacrylate or dimethylaminopropylacrylamide is copolymerized, and the carboxyl group or amino group and glycidyl methacrylate are copolymerized. A method of reacting a monomer having a polymerizable unsaturated group with a glycidyl group such as the simplest is preferable.

(Modified pigment (D) polymerizable unsaturated monomer (C) that is soluble in a non-aqueous solvent and becomes insoluble or hardly soluble after polymerization)
The polymerizable unsaturated monomer (C) used in the present invention that is soluble in the non-aqueous solvent and becomes insoluble or hardly soluble after polymerization is specifically exemplified by methyl (meth) acrylate, ethyl ( Such as olefins such as (meth) acrylate, n-propyl (meth) acrylate or i-propyl (meth) acrylate, or (meth) acrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride, vinyl fluoride or vinylidene fluoride, Vinyl monomers having no so-called reactive polar groups (functional groups); (meth) acrylamide, dimethyl (meth) acrylamide, Nt-butyl (meth) acrylamide, N-octyl (meth) acrylamide, diacetone acrylamide , Dimethylaminopropylacrylamide or alkoxylated N-methyl Amide bond-containing vinyl monomers such as rolled (meth) acrylamides; dialkyl [(meth) acryloyloxyalkyl] phosphates or (meth) acryloyloxyalkyl acid phosphates, or dialkyl [(meth) acryloyloxy Alkyl] phosphites or (meth) acryloyloxyalkyl acid phosphites; alkylene oxide adducts of the above (meth) acryloyloxyalkyl acid phosphates or acid phosphites, glycidyl (meth) acrylates and methylglycidyl (meta ) Ester compounds of epoxy group-containing vinyl monomers such as acrylate and phosphoric acid or phosphorous acid or their acidic esters, as well as 3-chloro-2-acid phosphoxypropipropylene Phosphorus atom-containing vinyl monomers such as (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, di-2-hydroxyethyl fumarate or mono-2-hydroxyethyl monobutyl fumarate Alternatively, polymerizable unsaturated carbo such as polypropylene glycol or polyethylene glycol mono (meth) acrylate, or “Placcel FM, FA monomer” (a caprolactone addition monomer manufactured by Daicel Chemical Industries, Ltd.) Hydroxyalkyl esters of acids or their adducts with ε-caprolactone, and unsaturated mono- or dicarboxylic acids such as (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid or citraconic acid In addition, polymerizable unsaturated carboxylic acids such as monoesters of these dicarboxylic acids and monohydric alcohols, or the above-mentioned polymerizable unsaturated carboxylic acid hydroxyalkyl esters and maleic acid, succinic acid, phthalic acid, hexa Various unsaturations such as adducts with anhydrides of polycarboxylic acids such as hydrophthalic acid, tetrahydrophthalic acid, hensentricarboxylic acid, benzenetetracarboxylic acid, "hymic acid", tetrachlorophthalic acid or dodecynyl succinic acid Carboxylic acids and “Cardura E”, palm oil fatty acid group Monoglycidyl esters of monovalent carboxylic acids such as sidyl esters or glycidyl octyl esters or adducts with monoepoxy compounds such as butyl glycidyl ether, ethylene oxide or propylene oxide, or adducts thereof with ε-caprolactone, or Hydroxyl-containing polymerizable unsaturated monomers such as hydroxy vinyl ether; Dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; Glycidyl (meth) acrylate, (β- Methyl) glucidyl (meth) acrylate, (meth) allyl glycidyl ether or polymerizable unsaturated carboxylic acids or mono-2- (meth) acryloyloxymonoethyl phthalate, etc. Various unsaturated carboxylic acids such as an equimolar adduct of an acid group-containing vinyl monomer and the polycarboxylic acid anhydride are added to “Epicron 200”, “Epicron 400”, “Epicron 441”, “Epicron 850” or “Epicron”. "Epicron 1050" (epoxy resin manufactured by Dainippon Ink & Chemicals, Inc.), "Epicoat 828", "Epicoat 1001" or "Epicoat 1004" (Epoxy resin manufactured by Japan Epoxy Resin Co., Ltd.), "Araldite 6071" or " Araldite 6084 "(epoxy resin manufactured by Ciba-Geigy, Switzerland), and also" Chissonox 221 "[epoxy compound manufactured by Chisso Corporation] or" Denacol EX-611 "[epoxy compound manufactured by Nagase Kasei Co., Ltd.] At least two per molecule Epoxy group-containing polymerizable unsaturated monomers such as an epoxy group-containing polymerizable compound obtained by addition reaction of various polyepoxy compounds having a poxy group at an equimolar ratio; 2-hydroxyethyl (meth) acrylate-hexa Isocyanate group-containing α, β-ethylenically unsaturated monomers such as methylene diisocyanate equimolar adducts and monomers having an isocyanate group and a vinyl group such as isocyanate ethyl (meth) acrylate; vinyl ethoxysilane, α- Alkoxysilyl group-containing polymerizable unsaturated compounds such as methacryloxypropyltrimethoxysilane, trimethylsiloxyethyl (meth) acrylate, silicon monomers such as “KR-215, X-22-5002” (product of Shin-Etsu Chemical Co., Ltd.) Monomers; and (meth) acrylic acid, croton Α, β-ethylenically unsaturated carboxylic acids such as unsaturated mono- or dicarboxylic acids such as acid, maleic acid, fumaric acid, itaconic acid or citraconic acid, and monoesters of these dicarboxylic acids with monohydric alcohols Acids, or 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4- Hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, di-2-hydroxyethyl fumarate, mono-2-hydroxyethyl monobutyl fumarate or polyethylene glycol mono (meth) acrylate, etc. Α, -Unsaturated carboxylic acid hydroalkyl esters of maleic acid, succinic acid, phthalic acid, hexahydrophthalic acid, tetrahydrophthalic acid, benzenetricarboxylic acid, benzenetetracarboxylic acid, "hymic acid", tetrachlorophthalic acid or dodecynyl succinic acid Carboxyl group-containing α, β-ethylenically unsaturated monomers such as adducts of polycarboxylic acid anhydrides and the like.
Of these, the use of C3 or lower alkyl (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate is preferred. Furthermore, in order to change the surface characteristics of the pigment surface and enhance the interaction with the pigment dispersant or pigment dispersion resin, at least one kind of carboxyl group, sulfonic acid group, phosphoric acid group, hydroxyl group, dimethylamino group, etc. It is preferable to copolymerize a polymerizable unsaturated monomer containing a functional group.

  In order to prevent the polymer from eluting from the pigment (A) when the modified pigment (D) is used, it is more preferable that the polymer is crosslinked. Examples of the polyfunctional polymerizable unsaturated monomer used as the crosslinking component include divinylbenzene, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di ( (Meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol dimethacrylate, trimethylolpropane tri Ethoxytri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol Sa (meth) acrylate or allyl methacrylate, and the like.

  Further, in a use range in which a polymer having an essential component of a polymerizable unsaturated monomer (C) that is soluble in at least one kind of the non-aqueous solvent and becomes insoluble or hardly soluble after polymerization is not dissolved in the non-aqueous solvent system. Other polymerizable unsaturated monomers may be used. Examples of other polymerizable unsaturated monomers include polymerizable unsaturated monomers that can be used other than the alkyl (meth) acrylates having an alkyl group having 4 or more carbon atoms and the alkyl (meth) acrylates described above. A monomer is mentioned.

The modified pigment (D) used in the present invention contains a pigment (A), a non-aqueous solvent, and a polymer (B) containing a polymerizable unsaturated group soluble in the non-aqueous solvent. It is obtained by polymerizing at least one polymerizable unsaturated monomer (C) that is soluble and insoluble or hardly soluble after polymerization.
The pigment (A) and the polymer (B) containing a polymerizable unsaturated group soluble in a non-aqueous solvent are preferably mixed before polymerization. As a mixing method, for example, a homogenizer, a disper, a bead mill, a paint shaker, a kneader, a roll mill, a ball mill, an attritor, a sand mill and the like can be used. In the present invention, the form of the pigment to be used is not limited, and any form of slurry, wet cake, and powder may be used. That is, in the production method of the present invention, even a pigment containing water such as a wet cake can be used.
After mixing the pigment (A) and the polymer (B), the polymerizable unsaturated monomer (C) and a polymerization initiator described later are further mixed and polymerized to obtain the modified pigment (D).
At that time, the amount of the polymer (B) used is not particularly limited because it is appropriately optimized depending on the purpose, but usually 1 to 200 parts is used with respect to 100 parts of the pigment (A), more preferably. 5 to 50 parts, more preferably 5 to 30 parts.
Further, the amount of the polymerizable unsaturated monomer (C) used is not particularly limited because it is appropriately optimized depending on the purpose, but usually 1 to 200 parts per 100 parts of the pigment (A). More preferably 5 to 50 parts, still more preferably 5 to 30 parts.

  The amount of the polymer (P) finally coated on the pigment is preferably 2 to 400 parts, more preferably 10 to 100 parts, and still more preferably 10 to 60 parts per 100 parts of the pigment (A). Part. In that case, it is preferable to use at least 1 sort of said polymerizable unsaturated monomer (C) normally in the ratio of 10-400 parts with respect to 100 parts of said polymers (B), Preferably it is 30-400. Parts, more preferably 50 to 200 parts.

A method of polymerizing the polymerizable unsaturated monomer (C) in the presence of the pigment (A), the non-aqueous solvent, and the polymer (B) may be performed by a known and conventional polymerization method. Usually, it is carried out in the presence of a polymerization initiator. Such polymerization initiators include azobisisobutyronitrile (AIBN), 2,2-azobis (2-methylbutyronitrile), benzoyl peroxide, t-butyl perbenzoate, t-butyl-2-ethylhexano A radical generating polymerization catalyst such as ate, t-butyl hydroperoxide, di-t-butyl peroxide, or cumene hydroperoxide may be used alone or in combination of two or more.
Since some polymerization initiators are difficult to dissolve in the non-aqueous solvent system, a method in which the polymerization initiator is dissolved in the polymerizable unsaturated monomer (C) and added to the mixed system of the pigment (A) and the polymer (B) is preferable. .
The polymerizable unsaturated monomer (C) or the polymerizable unsaturated monomer (C) in which the polymerization initiator is dissolved can be added by a dropping method in a state where the polymerization temperature is reached. A method of adding the polymer at a normal temperature before warming, heating the polymer after sufficiently mixing, and polymerizing is stable and preferable.
The polymerization temperature is usually in the range of 60 ° C to 130 ° C. In addition, when the pigment (A) is an organic pigment, if the polymerization temperature is too high, the pigment may undergo significant changes in form such as alteration and crystal growth. In that case, it is preferable to polymerize at 70 to 100 ° C.

  After the polymerization, the non-aqueous solvent used for the polymerization is removed by filtration, followed by drying and pulverization to obtain a powdered modified pigment (D). Nutsche, filter press, etc. can be used for the filtration method. Moreover, it can dry with well-known drying apparatuses, such as a box-type dryer, a vacuum dryer, a band dryer, and a spray dryer. For the pulverization, a known pulverizer such as a mortar, a hammer mill, a disk mill, a pin mill, or a jet mill can be used.

(Inkjet recording ink)
The ink for inkjet recording of the present invention comprises a pigment dispersant that can be dissolved in a diluent, a diluent that can dissolve the pigment dispersant, and the modified pigment (D).
In the present invention, the diluent specifically refers to an organic solvent or a low molecular weight photopolymerizable compound. If the diluent that can dissolve the pigment dispersant to be used is an organic solvent, it can be used as an oil-based ink for inkjet recording. Further, if the diluent capable of dissolving the pigment dispersant is a low molecular weight photopolymerizable compound, it can be used as a UV ink for inkjet recording.
Hereinafter, these two will be described in detail.

(Pigment dispersant soluble in diluent)
As the diluent used in the present invention, that is, a pigment dispersant that can be dissolved in an organic solvent or a low molecular weight photopolymerizable compound, a known one that is generally used for pigment dispersion using an organic solvent as a solvent may be used. it can. Examples include surfactants, pigment intermediates or derivatives, dye intermediates or derivatives, or resin-type dispersants such as polyamide resins, polyurethane resins, polyester resins, and acrylic resins. Among the above various dispersants, it is preferable to use a polyester-based resin and an acrylic resin.
Examples of commercially available resin-type dispersants include “DISPERBYK-130”, “DISPERBYK-161”, “DISPERBYK-162”, “DISPERBYK-163”, “DISPERBYK-170”, and “DISPERBYK-171” manufactured by BYK Chemie. ”,“ DISPERBYK-174 ”,“ DISPERBYK-180 ”,“ DISPERBYK-182 ”,“ DISPERBYK-183 ”,“ DISPERBYK-184 ”,“ DISPERBYK-185 ”,“ DISPERBYK-2000 ”,“ DISPERBYK-2001 ”, “DISPERBYK-2020”, “DISPERBYK-2050”, “DISPERBYK-2070”, “DISPERBYK-2096”, “DISPERBYK” 2150 ”,“ EFKA1503 ”,“ EFKA4010 ”,“ EFKA4020 ”,“ EFKA4300 ”,“ EFKA4330 ”,“ EFKA4340 ”,“ EFKA4520 ”,“ EFKA4530 ”,“ EFKA5054 ”,“ EFK5054 ”,“ EFT50505 ” "EFKA7422", "EFKA7431", "EFKA7441", "EFKA7461", "EFKA7496", "EFKA7496", Lubrizol's "Solsparse 3000", "Solsparse 9000", "Solsparse 13240", "Solsparse 13650", ""Sol Sparse 13940", "Sol Sparse 17000", "Sol Sparse 18000", "Sol Sparse 20000", "Sol Sparse 210" 0, “Sol Sparse 20000”, “Sol Sparse 24000”, “Sol Sparse 26000”, “Sol Sparse 27000”, “Sol Sparse 28000”, “Sol Sparse 32000”, “Sol Sparse 36000”, “Sol Sparse 37000”, “Sol Sparse 38000”, “Sol Sparse” "41000", "Solspers 42000", "Solspers 43000", "Solspers 46000", "Solspers 54000", "Solspers 71000", Ajinomoto Fine Techno Co., Ltd. products Ajisper "PB-711", "Azisper PB-821", " It is possible to use “Azisper PB-822”, “Azisper PB-814”, “Azisper PB-824”, and the like.
In addition, a leveling agent, a coupling agent, a cationic surfactant, and the like can be used together. In the present invention, two or more of these pigment dispersants can be used in combination.

(Diluent: Organic solvent)
Examples of the organic solvent used as a diluent for oil-based inks for inkjet recording include non-polar solvents such as long-chain fatty acid esters, vegetable oil esters, higher fatty acids, vegetable oils, hydrocarbons, and higher alcohols. It is done. Examples of highly polar solvents include lower alcohols, glycols, glycol ethers, glycol esters, lower alcohol esters, pyrrolidones and the like. When used in inkjet, a high boiling point is desirable in order to suppress drying at the head orifice.

  Non-polar solvents include, for example, methyl oleate, ethyl oleate, isopropyl oleate, isobutyl oleate, methyl linoleate, isobutyl linoleate, ethyl linoleate, soy oil methyl, soy oil isobutyl, linseed oil butyl, large Bean oil, linseed oil, castor oil, Nippon Oil Corporation “Nisseki Naphthezol H, No. 0 Solvent H, Isosol 300, Isosol 400, AF Solvent No. 5, AF Solvent No. 6, AF Solvent No. 7”, ExxonMobil “ ExxolD80, ExxolD110, ExxolD130, ExxolD140 "(all trade names), isomyristyl alcohol, isopalmityl alcohol, isostearyl alcohol, oleyl alcohol, isononanoic acid, isomyristic acid, hexadecanoic acid Isopalmitic acid, oleic acid, and isostearic acid.

  Examples of highly polar solvents include ethylene glycol, diethylene glycol, glycerin, xylitol, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol dimethyl ether, Examples include propylene glycol monomethyl ether monoacetate, isopropyl acetate, pyrrolidone, and N-methylpyrrolidone.

  Said solvent can be utilized individually or as a mixed solvent. By using a mixed solvent, it is possible to control the solubility of the binder resin and other additives described later, the evaporation rate of the solvent, and the suitability for the recording medium to be printed (ink fixability, dot spread).

  The organic solvent used alone or as a mixture is preferably as low as possible in order to obtain a viscosity that enables inkjet discharge as an oil-based ink for inkjet recording. If the viscosity of the solvent used alone or in mixture is too high, it becomes difficult to add pigments, binder resins, etc., making it difficult to make oil-based inks for ink jet recording, or only a small addition amount. This is disadvantageous in terms of ink design.

(Diluent: low molecular weight photopolymerizable compound)
The low-molecular photopolymerizable compound used as a diluent for UV ink for inkjet recording includes, for example, a radical polymerization type and a cation polymerization type, and both known photopolymerization compounds are widely used. can do.
As the radical polymerization type photopolymerizable compound, for example, monofunctional (meth) acrylate and polyfunctional (meth) acrylate can be used alone or in combination of two or more kinds.
Examples of the monofunctional (meth) acrylate that can be used in the present invention include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, amyl (meth) acrylate, and 2-ethylhexyl (meth) ) Acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, dodecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, methoxyethyl (meth) Acrylate, butoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, nonylphenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, dimethylamino ester (Metal such as til (meth) acrylate, diethylaminoethyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, etc. ) Acrylates.
Examples of the polyfunctional (meth) acrylate include 1,3-butylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol. Di (meth) such as neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, tricyclodecane dimethanol, ethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol Di (meth) acrylate of diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of acrylate, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, neopentyl glycol Obtained by adding 2 mol of ethylene oxide or propylene oxide to 1 mol of bisphenol A, and adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of diol di (meth) acrylate and trimethylolpropane. Diol or tri (meth) acrylate of triol, di (meth) acrylate of diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of bisphenol A, trimethylolpropane tri (meth) acrylate, penta Erythritol tri (meth) acrylate, poly (meth) acrylate of dipentaerythritol, ethylene oxide modified phosphoric acid (meth) acrylate, ethylene oxide modified alkyl phosphoric acid (meth) acrylate, etc. And the like.

Specific examples of the cationic polymerization type photopolymerizable compound include epoxy compounds and vinyl ether compounds.
Examples of epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, phenol novolac type epoxy compounds, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether and other aliphatic epoxy compounds, Daicel Chemical Industries, Ltd. Examples thereof include alicyclic epoxy compounds such as Celoxide 2000, 3000, and 4000 manufactured by Co., Ltd.
Specific examples of the vinyl ether compound include 2-hydroxyethyl vinyl ether, triethylene glycol vinyl monoether, tetraethylene glycol divinyl ether, trimethylolpropane trivinyl ether, and the like.
Among them, in order to obtain an ink having a low viscosity and a high curing / drying speed, it is preferable to use (meth) acrylate which is a radical polymerizable compound as the photopolymerizable compound.

If necessary, the photopolymerizable compound may be used in combination with the above-mentioned “organic solvent used as a diluent”. However, a large amount of use may reduce the curability and durability of the cured film. It is preferable to use a photopolymerizable compound having a particularly high solubility of the pigment dispersant as much as possible, since the solvent may remain in the printed matter and is not preferable for hygiene and environment. The content is preferably about 5% by weight or less of the ink.
As a photopolymerizable compound having high solubility, for example, as a radical polymerization type photopolymerizable compound, 2-hydroxy-3-phenoxypropyl (meth) acrylate, tetrafurfuryl (meth) acrylate, neopentyl glycol (meth) acrylate , 2-hydroxyethyl (meth) acrylate, benzyl (meth) acrylate, and the like. Among these, 2-hydroxy-3-phenoxypropyl acrylate is particularly preferable. The content of the (meth) acrylate that dissolves these pigment dispersants is preferably contained in the same amount or more as the content of the pigment dispersant in the ink.
Moreover, as a cationic polymerization type photopolymerizable compound which dissolves a pigment dispersant, it is preferable to use a low-viscosity alicyclic epoxy compound, and specifically, Celoxide 3000 can be mentioned.

(Other components Oil-based ink for ink-jet recording: binder resin, etc.)
When the ink for ink-jet recording of the present invention is used as an oil-based ink for ink-jet recording, it is preferable to add a binder resin in order to maintain the fixability of the recorded matter. As the binder resin, styrene- (meth) acrylic resin, styrene-maleic acid resin, rosin phenol resin, vinyl acetate resin, urethane resin, polyester resin, epoxy resin, silicone resin, etc. can be used. Insoluble resins are clogged at the head orifice and are difficult to use.
Further, if necessary, additives such as a surfactant and a wetting agent are added, and finally the modified pigment (D) is adjusted to 3 to 15% in terms of mass to obtain an oil-based ink for inkjet recording.
In addition, the obtained oil-based ink for ink-jet recording can remove coarse particles and adjust the particle size distribution of dispersed particles by performing ultracentrifugation or filtration with a microfilter, if necessary, such as nozzle clogging. Can be extremely reduced.

(Other components UV ink for inkjet recording: photopolymerization initiator)
When the inkjet recording ink of the present invention is used as a UV ink for inkjet recording, it is preferable to add a photopolymerization initiator because it is necessary to cure the photopolymerizable compound used as the diluent. .
Any known photo-radical polymerization initiator used in the present invention can be used. As the photopolymerization initiator, a molecular cleavage type or a hydrogen abstraction type is suitable for the present invention.
As radical photopolymerization initiators used in the present invention, benzoin isobutyl ether, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, benzyl, 2,4,6-trimethylbenzoyldiphenylphosphine oxide 6-trimethylbenzoyldiphenylphosphine oxide 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide and the like are preferable. In addition to these, molecular cleavage types other than these include 1-hydroxycyclohexyl phenyl ketone, benzoin ethyl ether, benzyl dimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- ( 4 -Isopropylphenyl) -2-hydroxy-2-methylpropan-1-one and 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, etc. may be used in combination. Benzophenone, 4-phenylbenzophenone, isophthalphenone, 4-benzoyl-4′-methyl-diphenyl sulfide, etc., which are hydrogen abstraction type photopolymerization initiators, can be used in combination.
For the photo radical polymerization initiator, as sensitizers, for example, trimethylamine, methyldimethanolamine, triethanolamine, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, N, An amine that does not cause an addition reaction with the polymerizable component, such as N-dimethylbenzylamine and 4,4′-bis (diethylamino) benzophenone, can also be used in combination. Of course, it is preferable to select and use the radical photopolymerization initiator and the sensitizer, which are excellent in solubility in the photocurable compound and do not inhibit the ultraviolet light transmittance.
The radical photopolymerization initiator and the sensitizer are used in the range of 0.1 to 20% by mass, preferably 4 to 12% by mass, based on the total amount of the photocurable compound and the photopolymerizable oligomer described below.

Any known photocationic polymerization initiator used in the present invention can be used. Specifically, polyarylsulfonium salts such as triphenylsulfonium hexafluoroantimonate and triphenylsulfonium hexafluorophosphate, polyaryls such as diphenyliodonium hexafluoroantimonate and P-nonylphenyliodonium hexafluoroantimonate An iodonium salt etc. can be mentioned. These photocationic polymerization initiators can be used in combination of two or more.
The photocationic polymerization initiator is used in the range of 0.1 to 20% by mass, preferably 1 to 10% by mass, based on the total amount of the photocurable compound and the photopolymerizable oligomer described below.

(Other components UV ink for inkjet recording: photopolymerizable oligomer)
When the ink for ink jet recording of the present invention is used as UV ink for ink jet recording, polyurethane (meth) acrylate is used for the purpose of maintaining the fixability of the recorded matter or imparting the curability and durability of the cured film. Photopolymerizable oligomers such as these can also be contained. The reason why the photo-curable composition containing polyurethane (meth) acrylate exhibits good curability is that the terminal double bond of polyurethane (meth) acrylate is compared with the terminal double bond of general (meth) acrylate. It is thought that it is because it is easy to cleave because there is a urethane bond in the vicinity. In addition, the wear resistance is improved due to the characteristics of polyurethane.
Polyurethane (meth) acrylate used for inkjet is low viscosity or easily reduced in viscosity by being diluted with (meth) acrylate even if the viscosity of polyurethane (meth) acrylate itself is high due to crystallinity etc. It is necessary to. For this purpose, it is desirable to use polyurethane (meth) acrylate obtained by reacting polyisocyanate and monohydroxy (meth) acrylate without using polyol such as long-chain polyether and polyester.
The polyurethane (meth) acrylate is preferably used in the range of 3 to 15% with respect to the total amount of the ink for inkjet recording, from the viewpoint of the viscosity and curability of the jet ink composition.

(ratio)
In the inkjet recording ink of the present invention, each of the pigment dispersant soluble in the diluent, the diluent (organic solvent or photopolymerizable compound) capable of dissolving the pigment dispersant, and the modified pigment (D) Although there is no particular limitation on the use ratio, in general, with respect to 100 parts of the modified pigment (D), 5 to 200 parts of a pigment dispersant, preferably 10 to 100 pigment dispersants, and more preferably, 10 to 60 pigment dispersants are used, and the diluent is used so that the total solid content of the modified pigment (D) and the pigment dispersant is 10 to 25%, preferably 10 to 20%.

(Distribution method)
The ink for inkjet recording of the present invention is obtained by dispersing the modified pigment (D) in a solution obtained by mixing the pigment dispersant and the diluent (organic solvent or photopolymerizable compound). At that time, a publicly known and commonly used pigment dispersion method can be used, and the pigment dispersion is performed using a dispersing machine such as a ball mill, a sand mill, a bead mill, a three-roll mill, a paint conditioner, an attritor, a dispersion stirrer, or an ultrasonic wave. I can do things. Specific dispersing equipment includes super apex mill (manufactured by Kotobuki Giken Kogyo Co., Ltd.), ultra apex mill (manufactured by Kotobuki Giken Kogyo Co., Ltd.), dry swerke PM-DCP stirring bead mill device (manufactured by dry swerke), pico glen mill ( Asada Iron Works Co., Ltd.).

  Examples of the grinding medium used for pigment dispersion include a zirconia or steel grinding medium, and among these, a zirconia grinding medium having excellent wear resistance is particularly preferable. Further, the diameter of the grinding medium is preferably in the range of 0.01 to 3.0 mm, particularly preferably in the range of 0.05 to 0.5 mm. When the diameter of the grinding medium is larger than 3.0 mm, the wet pulverization becomes insufficient, which is not preferable.

  In the present invention, by performing ink jet recording on a recording medium, a recorded matter in which a colored image is formed on the recording medium can be obtained.

  The ink for ink-jet recording of the present invention can be used in a method for ink-jet recording onto a known recording medium. Examples of the recording medium at this time include plain paper such as PPC paper, photographic paper (glossy), exclusive paper for ink-jet recording such as photographic paper (silk tone), and coating used for offset printing. A synthetic resin film such as paper or an OHP film may be used. In particular, the ink for ink jet recording of the present invention is effective for improving the color developability of a special paper for ink jet recording and a coated paper used for offset printing.

  Hereinafter, the present invention will be described with reference to examples. Unless otherwise specified, “parts” and “%” are based on mass.

<Reference Example 1 Synthesis of Polymer (B-1) Containing Polymerizable Unsaturated Group Soluble in Nonaqueous Solvent>
A four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas inlet tube was charged with 500 parts of heptane and 470 parts of butyl acetate, and the temperature was raised to 90 ° C. A mixture consisting of 985 parts of butyl acid, 15 parts of methacrylic acid, and 7 parts of 2,2′-azobis (2-methylbutyronitrile) was added dropwise over 5 hours. The reaction was continued with holding. After the temperature of the reaction solution was lowered to 50 ° C., a solution in which 0.2 part of t-butylpyrocatechol was dissolved in 15 parts of butyl acetate was added, and then 15 parts of glycidyl methacrylate and 30 parts of dimethylaminoethanol were added. The solution was heated to 80 ° C. and reacted at the same temperature for 10 hours to obtain a polymer (B-1) solution containing a polymerizable unsaturated group soluble in a non-aqueous solvent.

<Reference Example 2 Synthesis of Polymer (B-2) Containing Polymerizable Unsaturated Group Soluble in Nonaqueous Solvent>
In the same reactor as in Reference Example 1, 500 parts of heptane and 500 parts of butyl acetate were charged and the temperature was raised to 90 ° C. When the same temperature was reached, 950 parts of butyl acrylate and dimethylaminoethyl methacrylate were added. A mixture comprising 50 parts and 7 parts of 2,2′-azobis (2-methylbutyronitrile) was added dropwise over 5 hours, and the reaction was continued for 10 hours at the same temperature after completion of the addition. The temperature of the reaction solution was lowered to 50 ° C., a solution in which 0.2 part of t-butyl pyrocatechol was dissolved in 20 parts of butyl acetate was added, and 20 parts of glycidyl methacrylate was further added, and the temperature was raised to 80 ° C. By performing the reaction at the same temperature for 10 hours, a polymer (B-2) solution containing a polymerizable unsaturated group soluble in a non-aqueous solvent was obtained.

<Reference Example 3 Synthesis of Modified Pigment (D-1)>
222 parts of wet cake (pigment content 45%) of Fast Gen Blue TGR (Dai Nippon Ink Chemical Co., Ltd.), 10 parts of the polymer (B-1) obtained in Reference Example 1, 1.25 mm 600 parts of zirconia beads and 300 parts of heptane were placed in a polyethylene jar and mixed for 90 minutes with a paint shaker (Toyo Seiki Co., Ltd.). After dilution with 300 parts of heptane, the zirconia beads were removed to prepare a pigment mixture.
400 parts of the obtained pigment mixed solution was charged into a separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas introduction tube, and then methyl methacrylate (3) was used as the polymerizable monomer (C). A polymerizable monomer composition of 1 part and 1.7 parts of ethylene glycol dimethacrylate dissolved in 1 part of 2,2′-azobis (2-methylbutyronitrile) and 200 parts of heptane were added. . After stirring for 30 minutes at room temperature, the temperature was raised to 80 ° C., and the reaction was continued for 15 hours at the same temperature. After cooling, the modified pigment and the polymerization solvent were separated by filtration. The obtained modified pigment was dried with a hot air dryer at 100 ° C. for 5 hours and then pulverized with a pulverizer to obtain a modified pigment (D-1).

<Reference Example 4 Synthesis of Modified Pigment (D-2)>
222 parts of a wet cake (pigment content 45%) of Fast Gen Blue TGR (Dai Nippon Ink Chemical Co., Ltd.), 15 parts of the polymer (B-1) obtained in Reference Example 1, 1.25 mm 600 parts of zirconia beads and 300 parts of heptane were placed in a polyethylene jar and mixed for 90 minutes with a paint shaker (Toyo Seiki Co., Ltd.). After dilution with 300 parts of heptane, the zirconia beads were removed to prepare a pigment mixture.
400 parts of the obtained pigment mixed solution was charged into the same reactor as in Reference Example 3, and then 1 part of t-butylacrylamide sulfonic acid as 20 parts of ion-exchanged water was used as the polymerizable monomer (C). Add the dissolved one, and then add 2.2 parts of methyl methacrylate and 1.7 parts of ethylene glycol dimethacrylate to a polymerizable monomer composition of 1 of 2,2′-azobis (2-methylbutyronitrile). Dissolved parts and 200 parts of heptane were added. After stirring for 30 minutes at room temperature, the temperature was raised to 80 ° C., and the reaction was continued for 15 hours at the same temperature. After cooling, the modified pigment and the polymerization solvent were separated by filtration. The obtained modified pigment was dried at 100 ° C. for 5 hours with a hot air dryer and then pulverized with a pulverizer to obtain a modified pigment (D-2).

<Reference Example 5 Synthesis of Modified Pigment (D-3)>
222 parts of a wet cake (pigment content 45%) of Fast Gen Blue TGR (Dai Nippon Ink Chemical Co., Ltd.), 10 parts of AB-6 (polybutyl acrylate macromonomer manufactured by Toa Gosei Co., Ltd.) 600 parts of 25 mm zirconia beads and 300 parts of heptane were placed in a polyethylene jar and mixed for 60 minutes with a paint shaker (Toyo Seiki Co., Ltd.). After dilution with 400 parts of heptane, the zirconia beads were removed to prepare a pigment mixture.
400 parts of the obtained pigment mixed solution was charged into the reaction apparatus in the same manner as in Reference Example 3, and then 0.8 parts of t-butylacrylamide sulfonic acid as 20 parts of ion-exchanged water as the polymerizable monomer (C). 1 part of 2,2′-azobis (2-methylbutyronitrile) is added to a polymerizable monomer composition of 2 parts of methyl methacrylate and 1.5 parts of ethylene glycol dimethacrylate. And 140 parts of heptane were added. After stirring for 30 minutes at room temperature, the temperature was raised to 80 ° C., and the reaction was continued for 15 hours at the same temperature. After cooling, the polymer-treated pigment and the polymerization solvent were separated by filtration. The obtained polymer-treated pigment was dried at 100 ° C. for 5 hours with a hot air dryer and then pulverized with a pulverizer to obtain a modified pigment (D-3).

<Synthesis of Reference Example 6 Modified Pigment (D-4)>
First part super magenta RTS (quinacridone pigment manufactured by Dainippon Ink & Chemicals, Inc., CI Pigment Red 122) 250 parts of wet cake (pigment content 40%), polymer obtained in Reference Example 2 (B -2), 10 parts, 600 parts of 1.25 mm zirconia beads and 300 parts of heptane were placed in a polyethylene jar and mixed for 60 minutes with a paint shaker (Toyo Seiki Co., Ltd.). After dilution with 300 parts of heptane, the zirconia beads were removed to prepare a pigment mixture.
After charging 400 parts of the obtained pigment mixed liquid into the reactor in the same manner as in Reference Example 3, as a polymerizable monomer (C), 1 part of t-butylacrylamide sulfonic acid was added to 20 parts of ion-exchanged water. The dissolved one is added, and a polymerizable monomer composition of 1.8 parts of methyl methacrylate and 1.9 parts of ethylene glycol dimethacrylate is added with 0 of 2,2′-azobis (2-methylbutyronitrile). .9 parts dissolved and 200 parts heptane were added. After cooling, the polymer-treated pigment and the polymerization solvent were separated by filtration. The obtained polymer-treated pigment was dried at 100 ° C. for 5 hours with a hot air dryer and then pulverized with a pulverizer to obtain a modified pigment (D-4).

<Reference Example 7 Synthesis of Modified Pigment (D-5)>
100 parts of IRGAPHOR Yellow 8 GCF (Ciba Specialty Chemicals, Inc., CI Pigment Yellow 128), 15 parts of polymer (B-2) obtained in Reference Example 2, 600 parts of 1.25 mm zirconia beads 300 parts of heptane were put in a polyethylene jar and mixed for 60 minutes with a paint shaker (Toyo Seiki Co., Ltd.). After dilution with 400 parts of heptane, the zirconia beads were removed to prepare a pigment mixture.
After 400 parts of the obtained pigment mixed solution was charged into the reaction apparatus in the same manner as in Reference Example 3, as a polymerizable monomer (C), 0.5 parts of t-butylacrylamide sulfonic acid was ion-exchanged with 20 parts. What is dissolved in water is added, and further 2.2 parts of styrene and 4.7 parts of polymerizable monomer composition of divinylbenzene (55% component and 45% structural isomer (ethylvinylbenzene)) To the product, 1.5 parts of 2,2′-azobis (2-methylbutyronitrile) dissolved and 160 parts of heptane were added. After stirring for 30 minutes at room temperature, the temperature was raised to 80 ° C., and the reaction was continued for 15 hours at the same temperature. After cooling, the polymer-treated pigment and the polymerization solvent were separated by filtration. The obtained polymer-treated pigment was dried at 100 ° C. for 5 hours with a hot air dryer and then pulverized with a pulverizer to obtain a modified pigment (D-5).

<Synthesis of Reference Example 8 Modified Pigment (D-6)>
100 parts of carbon black # 960 (Mitsubishi Chemical Corporation CI Pigment Black 7), 20 parts of the polymer (B-1) obtained in Reference Example 1, 600 parts of 1.25 mm zirconia beads, heptane 300 parts were put into a polyethylene jar and mixed for 60 minutes with a paint shaker (Toyo Seiki Co., Ltd.). After dilution with 400 parts of heptane, the zirconia beads were removed to prepare a pigment mixture.
After 400 parts of the obtained pigment mixed solution was charged into the reaction apparatus in the same manner as in Reference Example 3, as a polymerizable monomer (C), 0.8 part of t-butylacrylamidesulfonic acid was subjected to 20 parts of ion exchange. What was dissolved in water was added to the polymerizable monomer composition of 4.3 parts of methyl methacrylate and 2.2 parts of ethylene glycol dimethacrylate, and 2,2′-azobis (2-methylbutyronitrile) Of 1.5 parts and 120 parts of heptane were added. After stirring for 30 minutes at room temperature, the temperature was raised to 80 ° C., and the reaction was continued for 15 hours at the same temperature. After cooling, the polymer-treated pigment and the polymerization solvent were separated by filtration. The obtained polymer-treated pigment was dried at 100 ° C. for 5 hours with a hot air dryer and then pulverized with a pulverizer to obtain a modified pigment (D-6).

<Reference Example 9 Synthesis Example of Polyurethane Acrylate>
Into a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas introduction tube, 606.7 parts of Plaxel FA-1 (Daicel chemical product, caprolactone-modified hydroxyethyl acrylate) was added, and the reaction solution temperature was stirred. Care was taken not to exceed 70 ° C., and 227.7 parts of tolylene diisocyanate was added dropwise from the dropping funnel. After completion of dropping, stirring was continued while maintaining the reaction solution temperature at 70 ° C., and after 1 hour, 0.1 part of dibutyltin dilaurate was added and stirring was continued. The reaction was further continued for 10 hours, and after confirming that there was no unreacted isocyanate group, polyurethane acrylate was obtained.

<Example 1 of oil-based ink for inkjet recording>
9.5 parts of the modified pigment (D-1) obtained in Reference Example 3, copper phthalocyanine monosulfonic acid (phthalocyanine derivative) 0.5 part as a dispersion aid, Ajisper PB814 (Ajinomoto Fine-Techno pigment dispersant, effective 5 parts of component 60%), 60 parts of propylene glycol monomethyl ether and 0.5 mmφ zirconia beads were added, dispersed for 4 hours with a paint conditioner (manufactured by Toyo Seiki Co., Ltd.), and diluted with 75 parts of propylene glycol monomethyl ether. By removing 0.5 mmφ zirconia beads, an oil-based ink for ink jet recording (Y1) was obtained.
The viscosity of the oil-based ink for ink jet recording (Y1) was 15 mPa · s under the conditions of 25 ° C. and 10 rpm with a RE550L viscometer manufactured by Toki Sangyo.
Further, after storage at 40 ° C. for 2 weeks, the viscosity was 15.5 mPa · s, the change was within ± 10%, and there was no sedimentation of the pigment, and the dispersion stability was high.
As a result of performing printing with an inkjet printer having a piezo-type head whose head temperature is kept at 45 ° C. and visually evaluating the printed state of the recorded matter, both the initial ink and the ink after the storage stability test are in a predetermined position. The ink was printed on the surface, and the dischargeability was good.

<Example 2 of UV ink for inkjet recording>
10 parts of the modified pigment (D-2) obtained in Reference Example 4, 3 parts of Ajisper PB821 (pigment dispersant manufactured by Ajinomoto Fine Techno Co., Ltd.), 7 parts of Aronix M5700 (manufactured by Toa Gosei Co., Ltd.), ethylene oxide addition 72 parts of 1,6-hexanediol diacrylate and 8 parts of 3-methoxybutyl acrylate were stirred and mixed with a stirrer for 1 hour and then treated with a bead mill for 4 hours to prepare a mill base.
Next, 4.5 parts of the polyurethane acrylate obtained in Reference Example 9, 9.5 parts of ethylene oxide-added trimethylolpropane triacrylate, 63.0 parts of ethylene oxide-added 1,6-hexanediol diacrylate, 3 -3.0 parts of methoxybutyl acrylate, 0.1 part of DC57Additive (a polyether modified silicone oil manufactured by Dow Corning), 4.0 parts of Irgacure 814 (manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator, After adding 3.0 parts of Darocur 1173 (manufactured by Ciba Specialty Chemicals) and heating and dissolving the photopolymerization initiator at 60 ° C., add 20 parts of the mill base and mix well. For ink jet recording by filtering with a 2μm membrane filter To give the V ink (UV1).
The viscosity of the UV ink for inkjet recording (UV1) was 23 mPa · s under the conditions of 25 ° C. and 10 rpm with a RE550L viscometer manufactured by Toki Sangyo.
The viscosity change after storage at 40 ° C. for 2 weeks was within ± 10%, and there was no sedimentation of the pigment and the dispersion stability was high.
As a result of performing printing with an inkjet printer having a piezo-type head whose head temperature is kept at 45 ° C. and visually evaluating the printed state of the recorded matter, both the initial ink and the ink after the storage stability test are in a predetermined position. The ink was printed on the surface, and the dischargeability was good.

Example 3 Example of UV Ink for Inkjet Recording
The inkjet recording UV ink (UV2) was prepared in the same manner as in Example 2 except that the pigment used was changed from the modified pigment (D-2) to the modified pigment (D-3) obtained in Reference Example 5. Obtained.
The viscosity of the UV ink for inkjet recording (UV2) was 21 mPa · s under the conditions of 25 ° C. and 10 rpm with a RE550L viscometer manufactured by Toki Sangyo.
The viscosity change after storage at 40 ° C. for 2 weeks was within ± 10%, and the dispersion stability was high without pigment settling.
As a result of performing printing with an inkjet printer having a piezo-type head whose head temperature is kept at 45 ° C. and visually evaluating the printed state of the recorded matter, both the initial ink and the ink after the storage stability test are in a predetermined position. The ink was printed on the surface, and the dischargeability was good.

<Example 4 of UV ink for inkjet recording>
10 parts of the modified pigment (D-4) obtained in Reference Example 6, 4.5 parts of Ajisper PB821 (pigment dispersant manufactured by Ajinomoto Fine Techno Co., Ltd.), 10.5 of Aronix M5700 (manufactured by Toa Gosei Co., Ltd.) Part, 67.5 parts of ethylene oxide-added 1,6-hexanediol diacrylate and 7.5 parts of 3-methoxybutyl acrylate were stirred and mixed with a stirrer for 1 hour and then treated with a bead mill for 4 hours to prepare a mill base. .
Next, 4.5 parts of the polyurethane acrylate obtained in Reference Example 9, 9.0 parts of ethylene oxide-added trimethylolpropane triacrylate, 49.5 parts of ethylene oxide-added 1,6-hexanediol diacrylate, 3- To 7.0 parts of methoxybutyl acrylate, 5.6 parts of Irgacure 369 (manufactured by Ciba Specialty Chemicals) was added as a photopolymerization initiator, and the photopolymerization initiator was heated and dissolved at 60 ° C. 30 parts of the mill base was added and mixed well, followed by filtration with a 1.2 μm membrane filter to prepare a UV ink for ink jet recording (UV3).
The viscosity of the UV ink for inkjet recording (UV3) was 22 mPa · s under the conditions of 25 ° C. and 10 rpm with a RE550L viscometer manufactured by Toki Sangyo.
The viscosity change after storage at 40 ° C. for 2 weeks was within ± 10%, and there was no sedimentation of the pigment and the dispersion stability was high.
As a result of performing printing with an inkjet printer having a piezo-type head whose head temperature is kept at 45 ° C. and visually evaluating the printed state of the recorded matter, both the initial ink and the ink after the storage stability test are in a predetermined position. The ink was printed on the surface, and the dischargeability was good.

<Example 5 of UV ink for inkjet recording>
10 parts of the modified pigment (D-5) obtained in Reference Example 7, 3.0 parts of Ajisper PB821 (pigment dispersant manufactured by Ajinomoto Fine Techno Co., Ltd.), 7.0 of Aronix M5700 (manufactured by Toa Gosei Co., Ltd.) 7.0 Part, 72.0 parts of ethylene oxide-added 1,6-hexanediol diacrylate and 8.0 parts of 3-methoxybutyl acrylate were stirred and mixed with a stirrer for 1 hour, and then treated with a bead mill for 4 hours to prepare a mill base. .
Next, 4.5 parts of the polyurethane acrylate obtained in Reference Example 9, 9.0 parts of ethylene oxide-added trimethylolpropane triacrylate, 69.0 parts of ethylene oxide-added 1,6-hexanediol diacrylate, 3- 17.5 parts of methoxybutyl acrylate, 0.1 part of DC57Additive (polyether-modified silicone oil manufactured by Dow Corning), 5.0 parts of Irgacure 369 (manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator, Darocur 1173 (Made by Ciba Specialty Chemicals) After adding 2.5 parts and heating and dissolving the photopolymerization initiator at 60 ° C., 40 parts of the mill base was added and mixed well, and then a 1.2 μm membrane. UV for inkjet recording by filtering with a filter Was obtained link the (UV4).
The viscosity of the UV ink for inkjet recording (UV4) was 19 mPa · s under the conditions of 25 ° C. and 10 rpm with a RE550L viscometer manufactured by Toki Sangyo.
The viscosity change after storage at 40 ° C. for 2 weeks was within ± 10%, and there was no sedimentation of the pigment and the dispersion stability was high.
As a result of performing printing with an inkjet printer having a piezo-type head whose head temperature is kept at 45 ° C. and visually evaluating the printed state of the recorded matter, both the initial ink and the ink after the storage stability test are in a predetermined position. The ink was printed on the surface, and the dischargeability was good.

<Example 6: UV ink for inkjet recording>
10 parts of the modified pigment (D-6) obtained in Reference Example 8, 6 parts of Ajisper PB821 (pigment dispersant manufactured by Ajinomoto Fine Techno Co., Ltd.), 14 parts of Aronix M5700 (manufactured by Toagosei Co., Ltd.), ethylene oxide 63 parts of the added 1,6-hexanediol diacrylate and 7 parts of 3-methoxybutyl acrylate were stirred and mixed with a stirrer for 1 hour, and then treated with a bead mill for 4 hours to prepare a mill base.
Next, 4.0 parts of the polyurethane acrylate obtained in Reference Example 9, 14.0 parts of ethylene oxide-added trimethylolpropane triacrylate, 39.0 parts of ethylene oxide-added 1,6-hexanediol diacrylate, 3 -Add 5.6 parts of Irgacure 369 (manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator to 8.0 parts of methoxybutyl acrylate and 0.1 part of DC57Additive (polyether-modified silicone oil made by Dow Corning) After adding 35 parts of the above mill base to a solution obtained by heating and dissolving the photopolymerization initiator at 60 ° C. and mixing well, it is filtered through a 1.2 μm membrane filter to produce a UV ink for inkjet recording (UV5). did.
The viscosity of the UV ink for inkjet recording (UV5) was 20 mPa · s under the conditions of 25 ° C. and 10 rpm with a RE550L viscometer manufactured by Toki Sangyo.
The viscosity change after storage at 40 ° C. for 2 weeks was within ± 10%, and there was no sedimentation of the pigment and the dispersion stability was high.
As a result of performing printing with an inkjet printer having a piezo-type head whose head temperature is kept at 45 ° C. and visually evaluating the printed state of the recorded matter, both the initial ink and the ink after the storage stability test are in a predetermined position. The ink was printed on the surface, and the dischargeability was good.

<Comparative Example 1 Comparative Example of Oil-Based Ink for Inkjet Recording>
An oil-based ink for ink jet recording (HY1) was prepared in the same manner as in Example 1 except that the pigment used was changed from the modified pigment (D-1) to Fast Gen Blue TGR (Blue Pigment from Dainippon Ink & Chemicals, Inc.). ) Was produced. The viscosity of the oil-based ink for inkjet recording (HY1) was 19 mPa · s under the conditions of 25 ° C. and 10 rpm with a RE550L viscometer manufactured by Toki Sangyo.
Further, the change in viscosity after storage at 40 ° C. for 2 weeks was within ± 10%, but there was a slight sedimentation of the pigment and there was a problem in dispersion stability.
As a result of printing with an inkjet printer having a piezo head with the head temperature kept at 45 ° C. and visually evaluating the printed state of the recorded matter, the initial ink can be printed at a predetermined position, and the discharge property is good. However, the ink ejection after the storage stability test was poor.

<Comparative Example 2 Comparative Example of UV Ink for Inkjet Recording>
A UV ink for ink jet recording (HUV1) was prepared in the same manner as in Example 2 except that the pigment used was changed from modified pigment (D-2) to Fast Gen Blue TGR (blue pigment from Dainippon Ink & Chemicals, Inc.). ) Was produced.
The viscosity of the inkjet recording UV ink (HUV1) was 28 mPa · s under the conditions of 25 ° C. and 10 rpm with a RE550L viscometer manufactured by Toki Sangyo.
Further, the viscosity change after storage at 40 ° C. for 2 weeks was 58 mPa · s, the precipitation of the pigment was confirmed a little, and the dispersion stability was low.
As a result of printing with an inkjet printer having a piezo head with the head temperature kept at 45 ° C. and visually evaluating the printed state of the recorded matter, the initial ink can be printed at a predetermined position, and the discharge property is good. However, the ink ejection after the storage stability test was poor.

<Comparative Example 3 Comparative Example of UV Ink for Inkjet Recording>
A UV ink for inkjet recording (in the same manner as in Example 6) except that the pigment to be used is changed from the modified pigment (D-6) to carbon black # 960 (CI Pigment Black 7 manufactured by Mitsubishi Chemical Corporation). HUV2) was prepared.
The viscosity of the UV ink for inkjet recording (HUV2) was 29 mPa · s under the conditions of 25 ° C. and 10 rpm with a RE550L viscometer manufactured by Toki Sangyo.
Further, the viscosity change after storage at 40 ° C. for 2 weeks was 61 mPa · s, the precipitation of the pigment was confirmed a little, and the dispersion stability was low.
As a result of printing with an inkjet printer having a piezo head with the head temperature kept at 45 ° C. and visually evaluating the printed state of the recorded matter, the initial ink can be printed at a predetermined position, and the discharge property is good. However, the ink ejection after the storage stability test was poor.

Claims (5)

A polymerizable dispersant which is soluble in a non-aqueous solvent on the surface of the pigment (A), including a pigment dispersant that can be dissolved in a diluent, a diluent that can dissolve the pigment dispersant, and a colorant. A polymer obtained by polymerizing a group-containing polymer (B) and at least one polymerizable unsaturated monomer (C) which is soluble in a non-aqueous solvent and becomes insoluble or hardly soluble after polymerization ( An ink for inkjet recording, comprising a modified pigment (D) having P). A pigment dispersant that can be dissolved in a diluent, a diluent that can dissolve the pigment dispersant, and a colorant, and the colorant is soluble in the pigment (A), a non-aqueous solvent, and a non-aqueous solvent. Modification by polymerizing at least one polymerizable unsaturated monomer (C) that is soluble in the non-aqueous solvent and becomes insoluble or hardly soluble after polymerization in the presence of the polymer (B) containing an unsaturated group An ink for ink-jet recording comprising a pigment (D). The inkjet recording ink according to claim 1, wherein the non-aqueous solvent includes an aliphatic hydrocarbon solvent and / or an alicyclic hydrocarbon solvent. The ink for inkjet recording according to any one of claims 1 to 3, wherein the diluent capable of dissolving the pigment dispersant is an organic solvent. The ink for inkjet recording according to any one of claims 1 to 3, wherein the diluent capable of dissolving the pigment dispersant is a photopolymerizable compound.