WO2015152291A1 - Ink composition, inkjet recording method, and colored body - Google Patents

Abstract

To provide an ink composition that has excellent discharge stability and redispersibility and has excellent rubfastness, an inkjet recording method that uses said ink composition, and a colored body that is colored using said ink composition. The abovementioned problem can be solved by means of an ink composition that contains a coloring agent, a polymer dispersing agent, a wax agent, and a liquid medium, said polymer dispersing agent being an A-B block polymer obtained by copolymerization according to a living radical polymerization method using a polymerization initiator, wherein said polymerization initiator is either a mixture of an organic tellurium compound represented by belowmentioned formula (1) and an organic ditellurium compound represented by belowmentioned formula (2), or a mixture of an organic tellurium compound represented by belowmentioned formula (1), an azo polymerization initiator, and an organic ditellurium compound represented by belowmentioned formula (2), and the A-B block polymer has an A block and a B block, wherein the monomer of which the A block is composed is at least one type of monomer represented by belowmentioned formula (3), and the monomer of which the B block is composed is benzyl methacrylate and/or benzyl acrylate. (In the formula, R¹ represents a C₁-C₈ alkyl group or the like, and R² and R³ represent hydrogen atoms or the like.) (In the formula, R⁵ represents a hydrogen atom or the like, and R⁶ represents a methyl group or the like.)

Description

Ink composition, ink jet recording method, and colored body

The present invention relates to an ink composition excellent in ejection stability and redispersibility and excellent in scratch resistance, an ink jet recording method using the ink composition, and a colored body colored with the ink composition.

A recording method using an ink jet printer, which is one of the representative methods among various color recording methods, generates ink droplets and attaches them to a recording material such as paper to perform recording. In recent years, the demand for industrial applications has increased, and even high-speed printing and various recording materials have been demanded to perform the same recording performance.

On the other hand, with respect to ink, there has been a strong demand for scratch resistance against friction that may occur on the printing screen without impairing good ejection stability and storage stability. A method for imparting scratch resistance by adding an agent and improving permeability to a recording material has been studied. However, in such a method, sufficient image density may not be obtained due to ink penetration.

Therefore, for example, as disclosed in Patent Documents 1 and 2, for example, by adding a resin to the ink, adhesion with a recording material is imparted to improve the scratch resistance. Yes.

However, with such a method, it was difficult to improve the scratch resistance without impairing good ejection stability.

In addition, pigments and other water-insoluble dyes are known to be excellent in various fastness properties such as light, ozone, and water, but they are insoluble in water. Once aggregated, it is difficult to disperse in water again. Due to such properties, there has been a drawback that troubles such as clogging of the recording head of the printer are likely to occur. For this reason, there is a strong demand for the ability to disperse in water again even when the ink is dry.
JP 2013-166844 A JP 2013-199605 A

An object of the present invention is to provide an ink composition excellent in ejection stability and redispersibility and excellent in scratch resistance, an ink jet recording method using the ink composition, and a colored body colored with the ink composition. To do.

As a result of intensive studies to solve the problems as described above, the present inventors have found that the ink composition contains at least a colorant, a polymer dispersant, a wax agent, and a liquid medium. The present inventors have found that the problems can be solved and completed the present invention.

That is, the present invention relates to the following 1) to 14).
1)
An ink composition containing a colorant, a polymer dispersant, a wax agent, and a liquid medium,
The polymer dispersant is an AB block polymer obtained by copolymerization by a living radical polymerization method using a polymerization initiator,
The polymerization initiator is a mixture of an organic tellurium compound represented by the following formula (1) and an organic ditellurium compound represented by the following formula (2), or an organic tellurium compound represented by the following formula (1), azo A system polymerization initiator and a mixture of organic ditellurium compounds represented by the following formula (2):
The AB block polymer has an A block and a B block,
An ink composition wherein the monomer constituting the A block is one or more types of monomers represented by the following formula (3), and the monomer constituting the B block is benzyl methacrylate and / or benzyl acrylate.

(In the above formula (1), R ¹ represents a C ₁ -C ₈ alkyl group, aryl group, substituted aryl group or aromatic heterocyclic group. R ² and R ³ are a hydrogen atom or C ₁ -C Represents an alkyl group of _8. R ⁴ represents an aryl group, a substituted aryl group, an aromatic heterocyclic group, an acyl group, an amide group, an oxycarbonyl group or a cyano group.

(In the above formula (2), R ¹ is the same as R ¹ in the above formula (1).)

(In the above formula (3), R ⁵ represents a hydrogen atom or an alkyl group which may have 4 carbon atoms, and R ⁶ represents a hydrogen atom or a methyl group.)

2)
The ink composition according to 1), wherein the polymer dispersant has an acid value of 90 mgKOH / g or more and 200 mgKOH / g or less.
3)
The ink composition as described in 1) or 2) above, wherein the polymer dispersant has a weight average molecular weight of 10,000 to 60,000.
4)
In the above formula (3), the monomer represented by the one or more formulas (3) is a monomer in which R ⁵ is a hydrogen atom, R ⁶ is a methyl group, and R ⁵ is an n-butyl group. The ink composition according to any one of 1) to 3), wherein R ⁶ is a monomer of a methyl group.

5)
The ink composition according to any one of 1) to 4), wherein the colorant is a pigment or a disperse dye.
6)
The ink composition according to any one of 1) to 5), wherein the colorant is coated with the polymer dispersant.
7)
The ink composition according to any one of 1) to 6) above, wherein the wax agent is at least one wax selected from polyethylene wax and polypropylene wax, or a mixed wax of these and paraffin wax.
8)
The ink composition according to any one of 1) to 7), wherein the wax agent is polyethylene wax or a mixed wax of polyethylene wax and paraffin wax.
9)
The ink composition according to any one of 1) to 8), wherein the wax agent is an aqueous wax emulsion.

10)
A method for producing an ink composition according to any one of claims 1 to 9,
The polymer dispersant is an AB block polymer;
Copolymerization by a living radical polymerization method using a polymerization initiator to obtain the AB block polymer;
Preparing a colored dispersion from the colorant and the polymer dispersant; and
Furthermore, a wax agent and a liquid medium are blended to obtain an ink composition,
The polymerization initiator is a mixture of an organic tellurium compound represented by the following formula (1) and an organic ditellurium compound represented by the following formula (2), or an organic tellurium compound represented by the following formula (1), azo A system polymerization initiator and a mixture of organic ditellurium compounds represented by the following formula (2):
The AB block polymer has an A block and a B block,
The monomer constituting the A block is one or more monomers represented by the following formula (3), and the monomer constituting the B block is benzyl methacrylate and / or benzyl acrylate,
A method for producing an ink composition.

(In the above formula (1), R ₁ represents a C ₁ -C ₈ alkyl group, aryl group, substituted aryl group or aromatic heterocyclic group. R ₂ and R ₃ are a hydrogen atom or C ₁ -C Represents an alkyl group of _8. R ₄ represents an aryl group, a substituted aryl group, an aromatic heterocyclic group, an acyl group, an amide group, an oxycarbonyl group or a cyano group.

(In the above formula (2), R ¹ is the same as R ¹ in the above formula (1).)

(In the above formula (3), R ₅ represents a hydrogen atom or an alkyl group which may have 4 carbon atoms, and R ₆ represents a hydrogen atom or a methyl group.)

11)
The colored dispersion is prepared by adding the colorant to an emulsion obtained by mixing a solution of a hydrophobic organic solvent in which the polymer dispersant is dissolved and a liquid mainly containing water containing a neutralizing agent. The method for producing an ink composition according to claim 10, wherein the ink composition is prepared by adding water and removing the solvent after dispersion.
12)
10. An ink jet recording method for performing recording by ejecting droplets of the ink composition according to any one of 1) to 9) according to a recording signal and attaching the droplets to a recording material.
13)
The inkjet recording method according to 12), wherein the recording material is an information transmission sheet.
14)
A colored body colored with the ink composition according to any one of 1) to 9) above.
15)
A colored product colored by the inkjet recording method described in 12) above.
16)
An inkjet printer loaded with a container containing the ink composition according to any one of 1) to 9) above.

According to the present invention, an ink composition excellent in ejection stability and redispersibility and excellent in scratch resistance, an ink jet recording method using the ink composition, and a colored body colored with the ink composition can be provided.

In this specification, “CI” means “color index”. In addition, in this specification, “%” and “parts” including examples and the like are described on a mass basis unless otherwise specified.

The ink composition is preferably a water-based ink composition, more preferably a water-based ink composition used for inkjet recording.
The colorant is not particularly limited, and known pigments, disperse dyes and the like can be used. A colorant can be used in combination as necessary.

Examples of the pigment mainly include inorganic pigments, organic pigments and extender pigments.
Examples of the inorganic pigment include carbon black, metal oxide, hydroxide, sulfide, ferrocyanide, and metal chloride.
Examples of carbon black include thermal black, acetylene black, oil furnace black, gas furnace black, lamp black, gas black, and channel black.

As the carbon black, carbon black pigments such as furnace black, lamp black, acetylene black and channel black are preferable. Specific examples of carbon black include Raven760ULTRA, Raven780ULTRA, Raven790ULTRA, Raven1060ULTRA, Raven1080ULTRA, Raven1170, Raven1190ULTRAII, Raven1200, Raven1250, Raven1255, Raven1500, Raven2000, Raven2500ULTRA, Raven3500, Raven5000ULTRAII, Raven5250, Raven5750, Raven7000 (Columbia Carbon Co., Ltd. ; Monarch700, Monarch800, Monarch880, Monarch900, Monarch1000, Monarch1100, Monarch13 0, Monarch1400, Regal1330R, Regal1400R, Regal1660R, MogulL (manufactured by Cabot Corporation); ColorBlackFW1, ColorBlackFW2, ColorBlackFW18, ColorBlackFW200, ColorBlackFW285, Printex35, PrintexU, PrintexV, Printex140U, Printex140V, SpecIalBlack4, SpecIalBlack4A, SpecIalBlack5, SpecialBlack6, Nerox305, Nerox505, Nerox510 , Nerox 605, Nerox 600 (manufactured by Orion Engineered Carbons); MA7, MA8, MA100, MA600, M F-88, No. 25, no. 33, no. 40, no. 47, no. 52, no. 900, no. 2300 (manufactured by Mitsubishi Chemical Corporation);

Examples of organic pigments include soluble azo pigments, insoluble azo pigments, insoluble diazo pigments, condensed azo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, perylene pigments, perinone pigments, thioindigo pigments, anthoraquinone pigments and quinophthalone pigments. Can be mentioned.

Specific examples of organic pigments include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 24, 55, 73, 74, 75, 83, 93, 94, 95, 97, 98, 108, 114, 128, 129, 138, 139, 150, 151, 154, 180, 185, 193, 199, 202, 213, etc. yellow; I. Pigment Red 5, 7, 12, 48, 48: 1, 57, 88, 112, 122, 123, 146, 149, 150, 166, 168, 177, 178, 179, 184, 185, 202, 206, 207, Red such as 254, 255, 257, 260, 264, 272; I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 22, 25, 60, 66, 80, etc .; C.I. I. Pigment Violet 19, 23, 29, 37, 38, 50, etc .; violet; I. Pigment Orange 13, 16, 68, 69, 71, 73, etc. Orange to brown; C.I. I. Pigment Green 7, 36, 54, etc .; C.I. I. Pigment Black 1, etc. Black;

Examples of extender pigments include silica, calcium carbonate, talc, clay, barium sulfate, and white carbon. These extender pigments are not used alone and are usually used in combination with an inorganic pigment or an organic pigment.

Examples of the disperse dye include known disperse dyes such as azobenzene disperse dyes and anthraquinone disperse dyes.

Suitable disperse dyes include, for example, C.I. I. Dispers Yellow 9, 23, 33, 42, 49, 54, 58, 60, 64, 66, 71, 76, 79, 83, 86, 90, 93, 99, 114, 116, 119, 122, 126, 149, 160, 163, 165, 180, 183, 186, 198, 200, 211, 224, 226, 227, 231, 237; I. Dispers Red 60, 73, 88, 91, 92, 111, 127, 131, 143, 145, 146, 152, 153, 154, 167, 179, 191, 192, 206, 221, 258, 283; I. Dispers Orange 9, 25, 29, 30, 31, 32, 37, 38, 42, 44, 45, 53, 54, 55, 56, 61, 71, 73, 76, 80, 96, 97; C.I. I. Dispers Violet 25, 27, 28, 54, 57, 60, 73, 77, 79, 79: 1; I. Dispers Blue 27, 56, 60, 79: 1, 87, 143, 165, 165: 1, 165: 2, 181, 185, 197, 202, 225, 257, 266, 267, 281, 341, 353, 354, 358, 364, 365, 368; and the like.

The content of the colorant in the total mass of the ink composition is usually preferably 1 to 30%, and 1 to 10%, more preferably 2 to 7%.

The polymer dispersant is represented by a mixture of an organic tellurium compound represented by the above formula (1) and an organic ditellurium compound represented by the above formula (2), or the above formula (1) as a polymerization initiator. And an AB block polymer obtained by copolymerization by a living radical polymerization method using any of a mixture of an organic tellurium compound, an azo polymerization initiator, and an organic ditellurium compound represented by the above formula (2). The AB block polymer means a polymer in which the A polymer and the B polymer are chemically bonded, and A and B mean polymerized polymers of different monomers. In the present specification, in the AB block polymer, the part (block) derived from the A polymer may be referred to as A block, and the part (block) derived from the B polymer may be referred to as B block.

In the above formula (1), R ¹ represents a C ₁ -C ₈ alkyl group, aryl group, substituted aryl group or aromatic heterocyclic group. R ² and R ³ represent a hydrogen atom or a C ₁ -C ₈ alkyl group. R ⁴ represents an aryl group, a substituted aryl group, an aromatic heterocyclic group, an acyl group, an amide group, an oxycarbonyl group or a cyano group.

In the above formula (1), examples of the C ₁ -C ₈ alkyl group in R ¹ include methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, sec-butyl, tert-butyl, cyclobutyl , N-pentyl, n-hexyl, n-heptyl, n-octyl, etc., straight chain, branched chain, or cyclic C ₁ -C ₈ alkyl group, specifically, 1 to carbon atoms It may be a linear alkyl group having 8 carbon atoms, a branched or cyclic alkyl group having 3 to 8 carbon atoms, and preferably a straight chain or branched chain having 1 to 4 carbon atoms. A chain C ₁ -C ₄ alkyl group, and the branched chain alkyl group specifically has 3 or 4 carbon atoms, more preferably a straight chain having 1 to 4 carbon atoms. Chain alkyl group More preferably, methyl, ethyl or n-butyl can be mentioned.
As the aryl group, phenyl, naphthyl and the like can be mentioned, and preferably phenyl can be mentioned.
Examples of the substituted aryl group include a phenyl group having a substituent and a naphthyl group having a substituent. Examples of the substituent include a halogen atom, a hydroxy group, an alkoxy group, an amino group, a nitro group, a cyano group, a carbonyl-containing group represented by —CORa (Ra═C ₁ -C ₈ alkyl group, aryl group, C ₁ -C ₈ alkoxy group, aryloxy group), sulfonyl group, trifluoromethyl group and the like, preferably trifluoromethyl-substituted phenyl group. One or two of these substituents may be substituted, preferably substituted at the para-position or ortho-position, and more preferably substituted at the para-position.
Furthermore, examples of the aromatic heterocyclic group include a pyridyl group, a pyrrole group, a furyl group, and a thienyl group.

In R ² or R ³ in the above formula (1), examples of the C ₁ -C ₈ alkyl group include the same alkyl groups as those described above for R ¹ .

Examples of the aryl group, substituted aryl group, and aromatic heterocyclic group in R ⁴ in the above formula (1) include the same groups as those represented by R ¹ in the above formula (1). it can.
Examples of the acyl group include a formyl group, an acetyl group, and a benzoyl group.
Examples of the amide group include carboxylic acid amides such as acetamide, malonamide, succinamide, maleamide, benzamide, and 2-fluamide, thioamides such as thioacetamide, hexanedithioamide, thiobenzamide, and methanethiosulfonamide, selenoacetamide, hexanediselenoamide, Examples include selenoamides such as selenobenzamide and methaneselenosulfonamide, N-substituted amides such as N-methylacetamide, benzanilide, cyclohexanecarboxanilide, and 2,4′-dichloroacetanilide.
Examples of the oxycarbonyl group include an alkoxycarbonyl group and an aryloxycarbonyl group, preferably a group represented by —COORb (Rb═H, C ₁ -C ₈ alkyl group, aryl group). Specifically, a carboxy group; an alkoxy group such as a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, an n-butoxycarbonyl group, a sec-butoxycarbonyl group, a tert-butoxycarbonyl group, and an n-pentoxycarbonyl group Is an alkoxycarbonyl group which is a linear or branched alkoxy group having 1 to 8 carbon atoms, preferably 1 to 5 carbon atoms; an aryl group such as a phenoxycarbonyl group is the number of carbon atoms 1 to 10 carbon atoms, preferably 1 to carbon atoms An aryloxycarbonyl group or an aryl group having 8; and the like. Among these, Preferably, an alkoxycarbonyl group whose alkoxy group is a C1-C4 linear or branched alkoxy group can be mentioned, More preferably, a methoxycarbonyl group and an ethoxycarbonyl group can be mentioned. Can be mentioned.

In the above formula (1), as preferred organic tellurium compounds, R ¹ represents a C ₁ -C ₄ alkyl group, R ² and R ³ represent a C ₁ -C ₄ alkyl group, and R ⁴ represents an aryl group. And a compound represented by a group, a substituted aryl group, or an oxycarbonyl group.
Particularly preferably, R ¹ represents a C ₁ -C ₄ alkyl group, R ³ and R ⁴ represent a hydrogen atom or a C ₁ -C ₄ alkyl group, and R ⁵ represents a phenyl group, a substituted phenyl group, a methoxy group, A carbonyl group and an ethoxycarbonyl group are preferable.

Specific examples of the organic tellurium compounds are as follows. (Methylterranylmethyl) benzene, (1-methylterranylethyl) benzene, 1-chloro-4- (1-methylterranylethyl) benzene, 1-trifluoromethyl-4- (1-methylterranylethyl) Benzene, 3,5-bis-trifluoromethyl-1- (1-methylterranylethyl) benzene, 1,2,3,4,5-pentafluoro-6- (1-methylterranylethyl) benzene, 2 -Methyl teranyl propionitrile, (2-methyl teranyl propyl) benzene, methyl 2-methyl teranyl-2-methyl-propionate, ethyl 2-methyl teranyl-2-methyl-propionate, 2-methyl teranyl-2-methyl-propio A nitrile etc. can be mentioned. In the above, all compounds in which the methyl terranyl moiety is changed to ethyl terranyl, n-butyl terranyl, n-octyl terranyl, etc. are also included. Other examples include all organic tellurium compounds described in International Publication No. 2004/014962 (page 4, line 25 to page 7, line 18).

The above-mentioned organic tellurium compound can be used to obtain a desired number average molecular weight polymer by appropriately adjusting the amount used. The preferred amount used is a value obtained by dividing the mass (unit is gram) of the raw material vinyl monomer by the number average molecular weight of the target polymer (the unit of the amount used is the number of moles). It is preferable to use an amount of about 3 to 3 times.

Depending on the type of vinyl monomer to be polymerized, in addition to the organic tellurium compound represented by the above formula (1) used as the polymerization initiator, the organic ditellurium compound represented by the above formula (2) (ditelluride compound). May be further added.

In the above formula (2), a preferable organic ditellurium compound is a compound in which R ₁ represents an alkyl group having 1 to 4 carbon atoms, an aryl group, a substituted aryl group, or an aromatic heterocyclic group. A preferred organic ditellurium compound is a compound in which R ₁ represents an alkyl group or aryl group having 1 to 4 carbon atoms, and a more preferred organic ditellurium compound is R ₁ having 1 to carbon atoms. It is a compound representing an alkyl group having 4 atoms. Here, examples of the alkyl group having 1 to 4 carbon atoms include linear, branched or cyclic alkyl groups having 1 to 4 carbon atoms. Specifically, May be a linear alkyl group having 1 to 4 carbon atoms or a branched or cyclic alkyl group having 3 to 4 carbon atoms, preferably 1 to carbon atoms. A linear or branched alkyl group having 4 atoms is exemplified, and a linear alkyl group having 1 to 4 carbon atoms is more preferred.

Specific examples of the ditelluride compound include dimethylditelluride, diethylditelluride, di-n-propylditelluride, diisopropylditelluride, dicyclopropylditelluride, di-n-butylditelluride, di-sec- Butyl ditelluride, di-tert-butyl telluride, dicyclobutyl telluride, diphenyl ditelluride, bis- (p-methoxyphenyl) ditelluride, bis- (p-aminophenyl) ditelluride, bis- (p-nitrophenyl) ditelluride, bis -(P-cyanophenyl) ditelluride, bis- (p-sulfonylphenyl) ditelluride, dinaphthyl ditelluride, dipyridyl ditelluride and the like.
Preferred are dimethyl ditelluride, diethyl ditelluride, di-n-propyl ditelluride, di-n-butyl ditelluride, and diphenyl ditelluride.
Particularly preferred are dimethyl ditelluride, diethyl ditelluride, di-n-propyl ditelluride and di-n-butyl ditelluride.

When the ditelluride compound represented by the above formula (2) is used, it is preferably 0.01 to 100 mol, more preferably 0 with respect to 1 mol of the organic tellurium compound represented by the above formula (1) used as the polymerization initiator. .1 to 10 mol, more preferably 0.1 to 5 mol.

As the polymerization initiator, an azo polymerization initiator may be used in addition to the organic tellurium compound. The azo polymerization initiator is not particularly limited as long as it is an initiator used for usual radical polymerization. For example, 2,2′-azobis (isobutyronitrile) (AIBN), 2,2′-azobis (2- Methylbutyronitrile) (AMBN), 2,2′-azobis (2,4-dimethylvaleronitrile) (ADVN), 1,1′-azobis (1-cyclohexanecarbonitrile) (ACHN), dimethyl-2,2 '-Azobisisobutyrate (MAIB), 4,4'-azobis (4-cyanovaleric acid) (ACVA), 1,1'-azobis (1-acetoxy-1-phenylethane), 2,2'- Azobis (2-methylbutyramide), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylamidinop) Pan) dihydrochloride, 2,2′-azobis [2- (2-imidazolin-2-yl) propane], 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2′-azobis (2,4,4-trimethylpentane), 2-cyano-2-propylazoformamide, 2,2′-azobis (N-butyl-2-methylpropionamide), 2,2′- And azobis (N-cyclohexyl-2-methylpropionamide).

These azo polymerization initiators are preferably selected as appropriate according to the reaction conditions.
For example, in the case of low temperature polymerization (40 ° C. or lower), 2,2′-azobis (2,4-dimethylvaleronitrile) (ADVN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), In the case of medium temperature polymerization (40 to 80 ° C.), 2,2′-azobis (isobutyronitrile) (AIBN), 2,2′-azobis (2-methylbutyronitrile) (AMBN), dimethyl-2,2 In the case of '-azobisisobutyrate (MAIB), 1,1'-azobis (1-acetoxy-1-phenylethane), high temperature polymerization (over 80 ° C), 1,1'-azobis (1-cyclohexanecarbonitrile) ) (ACHN), 2-cyano-2-propylazoformamide, 2,2′-azobis (N-butyl-2-methylpropionamide), 2,2′-azobis (N-cyclohexyl-2-me Le propionamide), it is preferable to use 2,2'-azobis (2,4,4-trimethylpentane).
In the reaction using an aqueous solvent, 4,4′-azobis (4-cyanovaleric acid) (ACVA), 2,2′-azobis (2-methylbutyramide), 2,2′-azobis (2-methylamidino) is used. Propane) dihydrochloride, 2,2′-azobis [2- (2-imidazolin-2-yl) propane], 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide] It is preferable to use it.

When the azo polymerization initiator is used, it is preferably 0.01 to 100 mol, more preferably 0.1 to 10 mol, still more preferably relative to 1 mol of the organic tellurium compound of the above formula (1) used as the polymerization initiator. It is desirable to use at a ratio of 0.1 to 5 mol.

A mixture of an organic tellurium compound represented by the above formula (1) and an organic ditellurium compound represented by the above formula (2), or an organic tellurium compound represented by the above formula (1), an azo polymerization initiator, and the above formula When a polymer dispersant is prepared using any of the mixture of organic ditellurium compounds represented by (2) as a polymerization initiator, it is characterized by containing an organic tellurium compound in the polymer dispersant component. The total amount of tellurium in the dispersant can be measured by using a known metal measuring method such as an analytical method or an atomic absorption method.
The ink composition containing the polymer dispersant may have a tellurium total amount of, for example, 1 to 65 ppm, preferably 1 to 40 ppm, depending on the content of the polymer dispersant and the method for preparing the pigment dispersion described below. Can be measured.

The monomer constituting the A polymer (A block) is a monomer represented by the above formula (3), and the monomer constituting the B polymer (B block) is benzyl methacrylate and / or benzyl acrylate. In formula (3), R ⁵ represents a hydrogen atom or an alkyl group that may have 4 carbon atoms, and R ⁶ represents a hydrogen atom or a methyl group. Further, when R ⁵ is a hydrogen atom and R ⁶ is a monomer (methacrylic acid) having a methyl group, or R ⁵ is an n-butyl group and R ⁶ is a monomer having a methyl group (butyl methacrylate) It is particularly preferable that these two types of monomers are used in combination. In the case of this combined use, the mass ratio of butyl methacrylate to methacrylic acid (butyl methacrylate / methacrylic acid) is preferably 1.3 to 2.2, more preferably 1.5 to 2.0, and 1.6 to 1 .8 is more preferred.
The monomer constituting the B polymer is at least one monomer selected from benzyl methacrylate and benzyl acrylate, preferably benzyl methacrylate. The B block contains, in addition to at least one monomer selected from benzyl methacrylate and benzyl acrylate, a monomer represented by the above formula (3), preferably acrylic acid and / or methacrylic acid, more preferably methacrylic acid, It may be a polymer containing 1% by mass or less, preferably 0.5% by mass or less, more preferably 0.2% by mass or less, of at least one monomer selected from methacrylate and benzyl acrylate.
In the AB block polymer, the mass% of the A block relative to the B block is preferably 60 to 90 mass%, more preferably 65 to 85 mass%, and further preferably 70 to 80 mass%.

The acid value of the polymer dispersant is preferably 90 to 200 mgKOH / g. More preferably, it is 100 to 150 mgKOH / g, still more preferably 100 to 120 mgKOH / g, and most preferably 100 to 110 mgKOH / g. When the acid value is too small, there is a problem that the solubility in water or a liquid medium is lowered. On the contrary, when the acid value is too large, the color developability may be lowered.

The weight average molecular weight of the polymer dispersant is preferably 10,000 to 60,000. More preferably, it is 10,000 to 40,000, and most preferably 15,000 to 30,000. If the weight average molecular weight is too small, the stability of the dispersion is lowered. In this specification, the weight average molecular weight (Mw) is a value determined in terms of polystyrene by gel permeation chromatography (GPC) using an N-methylpyrrolidone (NMP) buffer solution as a solvent.

The amount of the polymeric dispersant to be used is generally represented by a numerical value called a limiting ratio. This division ratio can be obtained by the following equation. In the following formula, the unit of each amount of the polymer dispersant and the pigment is based on mass.
Ratio = polymer dispersant / colorant

The limiting ratio is preferably 0.1 to 1.0, more preferably 0.1 to 0.6, and particularly preferably 0.2 to 0.4. If the limiting ratio is too small, the stability of the dispersion may be reduced, or the image of the printed matter may be deteriorated.

In order to dissolve a colored dispersion using a polymer dispersant in water, it is necessary to use a neutralizing agent. Examples of the neutralizing agent include alkali metal hydroxides, alkaline earth metal hydroxides, aliphatic amine compounds, and alcohol amine compounds.

Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Examples of the alkaline earth metal hydroxide include beryllium hydroxide, magnesium hydroxide, calcium hydroxide, and strontium hydroxide, but are preferably alkaline earth metal hydroxides, more preferably hydroxide. Lithium and sodium hydroxide.

Examples of the alcohol amine compound include monoethanolamine, diethanolamine, triethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, methylethanolamine, dimethylethanolamine and N-methyldiethanolamine, preferably tertiary amine. More preferably, it is triethanolamine.

Examples of the aliphatic amine compound include ammonia, monomethylamine, dimethylamine, trimethylamine, monoethylamine, dimethylamine and trimethylamine, preferably ammonia or triethylamine.

These neutralizers can be used alone or in combination.

The desired amount of the neutralizing agent can be used. When neutralization is performed with the theoretical equivalent of the acid value of the polymer dispersant, the degree of neutralization is 100%, and the neutralizing agent may be used in excess of the theoretical amount. The neutralization degree is preferably from 50 to 200%, more preferably from 80 to 150%, and most preferably from 100 to 120%.

When a polymer dispersant having an acid value exceeding 200 mgKOH / g is used, the same performance as when a low acid value dispersant is used is obtained by using a neutralization degree lower than 100% neutralization degree. May be.

The method for producing the ink composition is not particularly limited. As an example, there is a method in which a colored dispersion is prepared from a colorant and a polymer dispersant, and this is used for preparing an ink composition. The colored dispersion can be a microencapsulated pigment in which the surface of the colorant is coated with a polymer dispersant, or a non-microencapsulated dispersion. The former is preferred.

There are roughly two methods for coating the colorant surface with a uniform polymer dispersant: a physical / mechanical method and a chemical method. Among the latter chemical methods, a surface precipitation method, a kneading method, and an interfacial polymerization method have been proposed. Here, the surface precipitation method is a method for precipitating a polymer dispersant on the pigment surface by utilizing pH adjustment or a difference in solubility in a medium, and includes an acid precipitation method, a phase inversion emulsification method, and the like. The interfacial polymerization method is a method in which a monomer, oligomer, or pigment derivative is adsorbed on the pigment surface and then a polymerization reaction is performed, and is also called a surface polymerization method. Among these, the surface precipitation method is preferable, and a colored dispersion obtained by a phase inversion emulsification method is more preferable.

As a method for producing the above colored dispersion, a solution of a hydrophobic organic solvent in which a polymer dispersant is dissolved and a liquid containing water as a main component containing a neutralizing agent are mixed and emulsified (emulsion or micro-particle). There may also be mentioned a production method in which a colorant is added and mixed / dispersed therein, and then water is further added to remove the solvent.

For example, by using the above method, colorant particles having a polymer dispersant on the surface and an average particle diameter of 200 nm or less can be easily obtained. In particular, the average particle size is more preferably 50 nm to 150 nm, and more preferably 60 nm to 120 nm by selecting the type of colorant used, the type of polymer dispersant, the value of the acid value, the molecular weight, and the like. Is more preferable. As a result, it is possible to obtain an ink composition for ink jet recording, which can improve the ejection stability, and further increase the dispersion stability and the print density of the image, and the color product obtained thereby. Here, in this specification, an average particle diameter means the average particle diameter of the particle | grains measured using the laser light scattering method.

Examples of the method for dispersing the pigment include a method using a sand mill (bead mill), a roll mill, a ball mill, a paint shaker, an ultrasonic disperser, a microfluidizer, and the like. Among these, a sand mill is preferable. In addition, it is desirable to prepare a pigment dispersion using a sand mill under conditions where dispersion efficiency is increased by using beads with a small diameter (0.01 mm to 1 mm diameter) and increasing the filling rate of beads. .
By dispersing under such conditions, the particle size of the colorant can be reduced, and a dispersion having good dispersibility can be obtained. It is also preferable to remove components such as pigments having a large particle size by filtration and / or centrifugation after the dispersion is prepared. In addition, for the purpose of suppressing foaming during the preparation of the dispersion, an extremely small amount of the above-mentioned antifoaming agent such as silicone or acetylene glycol can be added. However, it is preferable to use an antifoaming agent that does not affect the dispersion, micronization, and stability after dispersion.

The wax agent is preferably a wax emulsion, and more preferably an aqueous wax emulsion. Natural wax and chemically synthesized wax can be used as the wax.
Natural waxes include petroleum waxes such as paraffin wax and microcrystalline wax, lignite waxes such as montan wax, plant waxes such as carnauba wax and canderia waxes, beeswax and lanolin as animal and plant waxes, etc. And an emulsion in which is dispersed in an aqueous medium.
Chemically synthesized waxes include homopolymer waxes such as polyethylene, polypropylene, and Fischer-Trop, and emulsions in which copolymer waxes such as ethylene vinyl acetate and ethylene acrylic acid are dispersed in an aqueous medium.
These waxes can be used alone or in combination.

Among the above, the wax emulsion is preferably at least one wax selected from polyethylene wax and polypropylene wax, or a mixed wax of these and paraffin wax; more preferably polyethylene wax or polyethylene wax and paraffin wax And an emulsion in which a mixed wax is dispersed in an aqueous medium.

The particle size of the wax emulsion is preferably 5 μm or less, more preferably 1 μm or less in order to prevent clogging of the inkjet head.

The product marketed as a wax emulsion, for example, BYK Co. CERAFLOUR925, CERAFLOUR929, CERAFLOUR950, CERAFLOUR991, AQUACER498, AQUACER507, AQUACER515, AQUACER526, AQUACER531, AQUACER537, AQUACER539, AQUACER552, AQUACER1547, AQUACER593, AQUAMAT208, AQUAMAT263, AQUAMAT272 , MINEPOL 221 etc .; Mitsui High Wax NL100, Mitsui High Wax NL200, Mitsui High Wax NL500, Mitsui High Wax 4202E, Mitsui High Wax 1105A, Mitsui High Wax manufactured by Mitsui Chemicals, Inc. Scan 2203A, Mitsui Hi-wax NP055, Mitsui Hi-wax NP505, and the like; manufactured by Sanyo Chemical Industries, Ltd. of KUE-100, KUE-11 and the like.

Among these wax agents, polyethylene wax includes CERAFLOUR 925, 929, 950, 991; AQUACER 507, 515, 552, 1547; AQUAMAT 208, 263, 272; MINEPOL 221; Mitsui High Wax NL100, NL200, NL500; KUE-100; Can be mentioned.
Moreover, AQUACER 531 is mentioned as a mixed wax of polyethylene wax and paraffin wax.
Examples of paraffin wax include AQUACER 498, 537; KUE11; and the like.
Examples of the polypropylene wax include AQUACER 593; Mitsui High Wax NP055, NP505, and the like.
Moreover, AQUACER 539 etc. are mentioned as a mixed wax of polypropylene wax and paraffin wax.

The content of the wax agent in the total mass of the ink composition is preferably 0.1% to 5%, particularly preferably 0.1% to 2%. If it is less than this, the effect of scratch resistance cannot be obtained.

The liquid medium means water or a water-soluble organic solvent containing water. The water-soluble organic solvent can be used alone or in combination.
Examples of the water-soluble organic solvent include C1-C1 such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol or tert-butanol, 1,2-hexanediol, 1,6-hexanediol, trimethylolpropane and the like. C6 alkanol; carboxylic acid amide such as N, N-dimethylformamide or N, N-dimethylacetamide; lactam such as 2-pyrrolidone, N-methyl-2-pyrrolidone or N-methylpyrrolidin-2-one; Cyclic ureas such as dimethylimidazolidin-2-one or 1,3-dimethylhexahydropyrimido-2-one; ketones such as acetone, 2-methyl-2-hydroxypentan-4-one, ethylene carbonate; Ketoalcohol; tetrahydrofuran, dioxane Cyclic ethers of ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,4-butylene glycol, 1,6-hexylene glycol, diethylene glycol, triethylene glycol , Tetraethylene glycol, dipropylene glycol, mono-, oligo- or polyalkylene glycols or thios having C2-C6 alkylene units such as polyethylene glycol, polypropylene glycol, thiodiglycol or dithiodiglycol having a molecular weight of 400, 800, 1540 or higher Glycols: polyols (triols) such as glycerin, diglycerin, hexane-1,2,6-triol; ethylene glycol monomethyl ether, ethylene glycol Cole monoethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether (butyl carbitol), triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, ethylene glycol monoallyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monomethyl ether, propylene glycol C1-C4 alkyl ethers of polyhydric alcohols such as monopropyl ether and triethylene glycol monobutyl ether; γ-butyrolactone or dimethyl sulfoxide;
Among these, isopropanol, 1,2-hexanediol, 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,2-propylene glycol, triethylene glycol, glycerin, ethylene glycol monoallyl ether, ethylene glycol monoisopropyl ether Diethylene glycol monomethyl ether, propylene glycol monopropyl ether and the like are preferable.
The ink composition may contain a water-insoluble organic solvent as one of the ink preparation agents in a range that does not cause layer separation of the ink composition. Examples of the water-insoluble organic solvent include C8-C16 (preferably C8-12) alkyl having a hydroxy group and an acyloxy group. Specific examples thereof include texanol.

The ink composition contains a colorant, a polymer dispersant, a wax agent, and a liquid medium, and the balance is water.

The pH of the ink composition is usually preferably 5 to 11 and preferably 7 to 10 for the purpose of improving storage stability. The surface tension is usually preferably 10 to 50 mN / m and 20 to 40 mN / m. The viscosity is usually preferably 30 mPa · s or less and 20 mPa · s or less.
The pH and surface tension of the ink composition can be appropriately adjusted with an ink preparation agent such as a pH adjuster or a surfactant.

Examples of the ink preparation agent include an antifungal agent, an antiseptic agent, a pH adjuster, a chelating reagent, an antirust agent, a water-soluble ultraviolet absorber, a water-soluble polymer compound, an antioxidant, and / or a surfactant. . The total content of the ink preparation agent in the total mass of the ink composition is about 0 to 30%. .

Specific examples of the antifungal agent include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, ethyl p-hydroxybenzoate, 1,2-benzisothiazolin-3-one or a salt thereof. .

Examples of preservatives include organic sulfur, organic nitrogen sulfur, organic halogen, haloaryl sulfone, iodopropargyl, haloalkylthio, nitrile, pyridine, 8-oxyquinoline, benzothiazole , Isothiazoline, dithiol, pyridine oxide, nitropropane, organotin, phenol, quaternary ammonium salt, triazine, thiazine, anilide, adamantane, dithiocarbamate, brominated indanone, benzyl Examples thereof include bromoacetate-based or inorganic salt-based compounds. Specific examples of the organic halogen compound include, for example, sodium pentachlorophenol. Specific examples of the pyridine oxide compound include sodium 2-pyridinethiol-1-oxide. Examples of the isothiazoline compound include 1,2-benzisothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 5- And chloro-2-methyl-4-isothiazolin-3-one magnesium chloride, 5-chloro-2-methyl-4-isothiazolin-3-one calcium chloride, 2-methyl-4-isothiazolin-3-one calcium chloride It is done. Specific examples of other antiseptic / antifungal agents include anhydrous sodium acetate, sodium sorbate or sodium benzoate, trade names Proxel GXL (S) and Proxel XL-2 (S) manufactured by Arch Chemical Co., Ltd.

As the pH adjuster, any substance can be used as long as it can control the pH of the ink in the range of, for example, 5 to 11 without adversely affecting the prepared ink. Specific examples thereof include alkanolamines such as diethanolamine, triethanolamine and N-methyldiethanolamine; alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; ammonium hydroxide (ammonia water); Alternatively, alkali metal carbonates such as lithium carbonate, sodium carbonate, sodium hydrogen carbonate, and potassium carbonate; alkali metal salts of organic acids such as sodium silicate and potassium acetate; inorganic bases such as disodium phosphate, and the like.

Specific examples of the chelating reagent include, for example, disodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate or sodium uracil diacetate.

Specific examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite, and the like.

Examples of water-soluble UV absorbers include sulfonated benzophenone compounds, benzotriazole compounds, salicylic acid compounds, cinnamic acid compounds, and triazine compounds.

Specific examples of the water-soluble polymer compound include polyethylene glycol, polyvinyl alcohol, cellulose derivatives, polyamine or polyimine.

As examples of the antioxidant, for example, various organic and metal complex anti-fading agents can be used. Examples of the organic anti-fading agent include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines or heterocyclic rings. .

Examples of the surfactant include known surfactants such as an anionic surfactant, a cationic surfactant, a nonionic surfactant, an amphoteric surfactant, a silicone surfactant, and a fluorine surfactant. It is done.

Examples of the anionic surfactant include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl ether sulfates, N-acyl amino acids or salts thereof, N-acyl methyl taurate salts, Alkyl sulfate polyoxyalkyl ether sulfate, alkyl sulfate polyoxyethylene alkyl ether phosphate, rosin acid soap, castor oil sulfate ester, lauryl alcohol sulfate ester, alkylphenol type phosphate ester, alkyl type phosphate ester, alkylaryl sulfone Acid salts, diethylsulfosuccinate, diethylhexylsulfosuccinate, dioctylsulfosuccinate and the like. Other specific examples include, for example, Hightenol LA-10, LA-12, LA-16, NE-15, Neohaitenol ECL-30S, ECL-45 (all trade names) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. ) And the like.

Examples of cationic surfactants 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, and imidazoline derivatives. Can be mentioned.

Nonionic surfactants include ethers such as polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether; Ester systems such as polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate; 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl Acetylene glycol (alcohol) type such as lu-1-hexyn-3-ol; trade name Surfynol 104, 105PG50, 82, 420, 440, 465, 485 manufactured by Nissin Chemical Co., Olfine STG; Polyglycol ether type ( For example, TIGItol 15-S-7 manufactured by SIGMA-ALDRICH);
Among these, acetylene glycol-based or acetylene alcohol-based surfactants and trade name Surfynol Series are preferable.

Examples of silicone surfactants include polyether-modified siloxane and polyether-modified polydimethylsiloxane. Examples thereof include BYK-345, BYK-348 (manufactured by Big Chemie, polyether-modified polydimethylsiloxane), BYK-347 (same as polyether-modified siloxane), BYK-349, BYK-3455, and the like.

Examples of the fluorosurfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate ester compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group as a side chain. And polyoxyalkylene ether polymer compounds. Examples include Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, Capstone FS-30, FS-31 manufactured by DuPont; PF-151N, PF manufactured by Omninova -154N; F-114, F-410, F-444, EXP. TF-2066, EXP. TF-2148, EXP. TF-2149, F-430, F-477, F-552, F-553, F-554, F-555, F-556, F-557, F-558, F-559, F-561, F- 562, R-40, R-41, RS-72-K, RS-75, RS-76-E, RS-76-NS, RS-77, EXP. TF-1540, EXP. TF-1760; BYK-3440 and BYK-3441 manufactured by BYK Chemie.

Among these surfactants, silicone surfactants and fluorine surfactants are preferable, and silicone surfactants are more preferable in consideration of environmental load and the like.

When the ink composition is used for ink jet recording, it is preferable to use a material containing a small amount of inorganic impurities such as metal cation chloride (for example, sodium chloride) and sulfate (for example, sodium sulfate) contained in the colored ink. preferable. The standard of the content of inorganic impurities is approximately 1% by mass or less with respect to the total mass of the colorant, and the lower limit may be equal to or less than the detection limit of the analytical instrument, that is, 0%. As a method for obtaining a colorant having a small amount of inorganic impurities, for example, a method using a reverse osmosis membrane; a method in which a colorant is suspended and purified in a mixed solvent of C1-C4 alcohol such as methanol and water; Examples include purification methods such as a method of exchanging and adsorbing impurities.

The above ink composition can be used in various fields. Examples thereof include water-based ink for writing, water-based printing ink, information recording ink, textile printing and the like, and it is preferably used for ink-jet recording.

The ink jet recording method is a method of recording by ejecting droplets of the ink composition in accordance with a recording signal and attaching them to a recording material. The ink nozzles used for recording are not particularly limited and can be appropriately selected according to the purpose.

As a recording method, for example, a charge control method that ejects ink using electrostatic attraction force; a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezo element; Irradiation and acoustic ink jet method that ejects ink using the radiation pressure; thermal ink jet that heats ink to form bubbles and uses the generated pressure, that is, bubble jet (registered trademark) method, etc. A method is mentioned. In the ink jet recording method, a method called a photo ink, in which a large number of inks having a small pigment content in the ink are ejected in a small volume; a plurality of pigments having substantially the same hue and different pigment contents in the ink. A method for improving image quality by using ink together; a method using a colorless and transparent ink, and the like are also included.

Examples of the colored body include substances colored with the ink composition. Preferably, the recording material colored by the ink jet recording method is used.
The substance is not particularly limited as long as it can be colored. Although there is no restriction | limiting in particular as said recording material, For example, information transmission sheets, such as paper and a film, a fiber, cloth (cellulose, nylon, wool, etc.), leather, a base material for color filters, etc. are mentioned. Among these, an information transmission sheet is preferable.

Information transmission sheets include plain paper without an ink receiving layer, media used for gravure printing, offset printing, etc .; dedicated ink jet paper, ink jet exclusive film, glossy paper, or glossy film with ink receiving layer; Cloth (cellulose, nylon, wool, etc.); leather; base material for color filter;
The ink receiving layer may be formed by, for example, impregnating or coating the base material with a cationic polymer; or inorganic fine particles capable of absorbing pigments in ink such as porous silica, alumina sol, and special ceramics such as polyvinyl alcohol and polyvinyl pyrrolidone. A method of coating the surface of the base material together with a hydrophilic polymer;

As the information transmission sheet, plain paper that has not been surface-treated can be suitably used. Generally, plain paper is not coated on both sides, and water-based ink bleeding (feathering) tends to occur along the fiber direction of the pulp exposed on the surface. Therefore, in many cases, a sizing agent of about 0.1% by mass is added to the pulp mass in order to suppress bleeding of the aqueous ink. The above plain paper has the effect of suppressing the bleeding of aqueous ink by adding a sizing agent and improving the image quality, but has the property of lowering the penetration speed of aqueous ink, and is basically an ink jet recording that uses the osmotic drying method. For recording media, it is difficult to obtain early drying properties. However, it is one of the important characteristics of the ink composition of the present invention that suitable scratch resistance can be obtained even for these media.

Further, as the information transmission sheet, a non-hardly absorbable recording material can be suitably used. Specific examples thereof include coated paper, and examples include finely coated paper, art paper, coated paper, matte paper, and cast paper.
Coated paper is paper whose surface is coated with a paint to enhance aesthetics and smoothness. Examples of the paint include a mixture of various clays such as talc, pyrophyllite, and kaolin, titanium oxide, magnesium carbonate, calcium carbonate, and the like, and starch and / or polyvinyl alcohol.
The paint can be applied to the paper using a coater in the paper manufacturing process, for example. There are two types of coaters: an inline system in which papermaking and coating are performed in one process by being directly connected to a papermaking machine, and an off-line system in which the process is separate from papermaking.
The finely coated paper refers to a recording paper having a coating amount of paint of 12 g / m ² or less. Art paper refers to recording paper obtained by applying a coating of about 40 g / m ^{2 to} high-grade recording paper (quality paper, paper with a chemical pulp usage rate of 100%). Coated paper and matte paper refer to recording paper coated with a paint of about 20 to 40 g / m ² . The cast paper refers to a recording paper obtained by finishing art paper or coated paper by applying pressure to the surface with a machine called a cast drum so that the gloss and the recording effect are further enhanced.

When recording on a recording material by the inkjet recording method, for example, a container containing the ink composition may be set at a predetermined position of an inkjet printer, and recording may be performed on the recording material by the recording method. it can.
The ink jet recording method is used in combination with ink compositions of various colors such as black, green, blue (or violet) and red (or orange) as well as the three primary colors of yellow, cyan, and magenta as necessary. You can also record.
The ink composition of each color is poured into each container, and each container can be loaded into a predetermined position of the ink jet printer and used for ink jet recording.

Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to the following examples. In addition, operations such as each synthesis reaction and crystallization were performed under stirring unless otherwise specified.

[Preparation Example 1]: Preparation of magenta aqueous dispersion 1.
A block copolymer described in Synthesis Example 3 of International Publication No. 2013/115071 was prepared, and the obtained polymer dispersant was dissolved in 6 parts and 30 parts of 2-butanone to obtain a uniform solution. A solution obtained by dissolving 0.44 parts of sodium hydroxide in 41 parts of ion-exchanged water was added thereto, and the mixture was stirred for 1 hour to prepare an emulsified solution in which the polymer dispersant was dissolved. At this time, there was no precipitation of crystals. In addition, C.I. I. 20 parts of Pigment Red 122 (manufactured by Clariant, Inkjet Magenta E02) was added, and dispersion was performed with a sand grinder. The dispersion was carried out for 15 hours under the condition of 1500 rpm. Thereafter, 100 parts of ion-exchanged water was added dropwise, and the beads for dispersion were removed by filtration. Then, 2-butanone and water were distilled off under reduced pressure using an evaporator, and a magenta dispersion having a pigment solid content of 12.0% was obtained. . The solid content in the aqueous solution was measured by dry weight method using MS-70 manufactured by A & D Corporation. At this time, the pH was 9.3, the average particle size was 106 nm, and the viscosity was 6.2 mPa · s. The resulting colored dispersion is referred to as “Dispersion 1”.

[Preparation Example 2]: Preparation of magenta aqueous dispersion 2.
Joncryl 68 (MW: 13000) 11.3 parts and 6 parts of triethanolamine were dissolved in 95.2 parts of ion-exchanged water and stirred for 1 hour. To the resulting solution, C.I. I. 37.5 parts of Pigment Red 122 (manufactured by Clariant, Inkjet Magenta E02) was added, and dispersion treatment was performed with a sand grinder at 1500 rpm for 20 hours. After 150 parts of ion-exchanged water was dropped into the obtained dispersion, this liquid was filtered to remove the dispersion beads, thereby obtaining a dispersion having a solid content of 15.8%. The resulting dispersion is referred to as “Dispersion 2”.

[Examples 1 to 4 and Comparative Examples 1 to 6]: Preparation of ink compositions.
The components shown in Table 1 below were mixed and stirred for about 1 hour, and then impurities were filtered off with a 3 μm membrane filter to obtain ink compositions of Examples and Comparative Examples. Each ink composition was prepared such that the content of the colorant contained in the total mass was 5%.

[Discharge stability test]
Each ink composition of Examples and Comparative Examples was printed 10 times as a 100% Duty image on Pearl Coat N (Made by Mitsubishi Paper Industries, Ltd .: 127.9 g / m ² ) using a Seiko Epson inkjet printer, product name PX105. went. Thereafter, a nozzle check image was printed, and the ejection stability during printing was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 2 below.
A: Solid printing has been stably performed, and the nozzle check image has no pin missing.
B: Although fading or ink scattering is confirmed in solid printing, there is no pin missing in the nozzle check image.
C: Faint or scattered ink is confirmed in solid printing, and there is a pin missing in the nozzle check image.

[Abrasion resistance test]
A 100% duty image obtained when solid printing was performed in the above [Discharge stability test] was dried at 90 ° C. for 2 minutes, and this was used as a test piece.
The printed surface of each test piece was overlapped with the blank paper surface of pearl coat N before printing. After the 500 g load was reciprocated 20 times on the two-layer paper surface, the pearl coat N was peeled off from each test piece. The state of the image of the test piece thus obtained and the state of color transfer to the white paper surface of the pearl coat N before printing were visually observed and evaluated according to the following evaluation criteria. The evaluation results are shown in Table 2 below.
A: There is no color transfer to the white paper surface, and the image of the test piece is not damaged.
B: Color transfer to the white paper surface and scratches on the test piece image are slightly noticeable.
C: The color transfer to the blank paper surface and the scratches on the solid printing part are both large and very conspicuous.

[Redispersibility evaluation]
Each of the ink compositions of Examples and Comparative Examples was placed on a glass petri dish with 10 μL, and dried for 5 hours with a constant temperature and humidity machine at 60 ° C. To the dried ink composition, 2 ml of ion-exchanged water was dropped at room temperature, and it was visually evaluated whether or not it was redispersed. When re-dispersion occurred, the transparent ion-exchanged water was discolored like a blur and could be judged visually. It means that clogging at the nozzle is less likely to occur as the re-dispersion easily occurs, and the performance of the ink composition is better. The results are shown in Table 2 below.
A: All are redispersed without residue.
B: A little residue remains, but most are redispersed.
C: Not redispersed at all.
In Table 2 below, Comparative Examples 2 and 3 were not subjected to the scratch resistance test because of poor ejection stability.

As is clear from the above results, it was confirmed that the dispersion liquid of each Example satisfied all of the ejection stability, scratch resistance and redispersibility.

The ink composition of the present invention is extremely useful as various recording inks, particularly ink jet recording inks, because it satisfies all of ejection stability, scratch resistance and redispersibility.

Claims (16)

1. An ink composition containing a colorant, a polymer dispersant, a wax agent, and a liquid medium,
   The polymer dispersant is an AB block polymer obtained by copolymerization by a living radical polymerization method using a polymerization initiator,
   The polymerization initiator is a mixture of an organic tellurium compound represented by the following formula (1) and an organic ditellurium compound represented by the following formula (2), or an organic tellurium compound represented by the following formula (1), azo A system polymerization initiator and a mixture of organic ditellurium compounds represented by the following formula (2):
   The AB block polymer has an A block and a B block,
   An ink composition wherein the monomer constituting the A block is one or more types of monomers represented by the following formula (3), and the monomer constituting the B block is benzyl methacrylate and / or benzyl acrylate.
   

   

   (In the above formula (1), R ¹ represents a C ₁ -C ₈ alkyl group, aryl group, substituted aryl group or aromatic heterocyclic group. R ² and R ³ are a hydrogen atom or C ₁ -C Represents an alkyl group of _8. R ⁴ represents an aryl group, a substituted aryl group, an aromatic heterocyclic group, an acyl group, an amide group, an oxycarbonyl group or a cyano group.
   

   

   (In the above formula (2), R ¹ is the same as R ¹ in the above formula (1).)
   

   

   (In the above formula (3), R ⁵ represents a hydrogen atom or an alkyl group which may have 4 carbon atoms, and R ⁶ represents a hydrogen atom or a methyl group.)
2. 2. The ink composition according to claim 1, wherein the polymer dispersant has an acid value of 90 mgKOH / g or more and 200 mgKOH / g or less.
3. The ink composition according to claim 1 or 2, wherein the polymer dispersant has a weight average molecular weight of 10,000 to 60,000.
4. The monomer represented by the one or more formulas (3) is a monomer in which R ⁵ is a hydrogen atom and R ⁶ is a methyl group in formula (3), and R ⁵ is an n-butyl group, The ink composition according to any one of claims 1 to 3, wherein R ⁶ is two types of monomers of a methyl group.
5. The ink composition according to any one of claims 1 to 4, wherein the colorant is a pigment or a disperse dye.
6. The ink composition according to any one of claims 1 to 5, wherein the colorant is coated with the polymer dispersant.
7. The ink composition according to any one of claims 1 to 6, wherein the wax agent is at least one wax selected from polyethylene wax and polypropylene wax, or a mixed wax of these and paraffin wax.
8. The ink composition according to any one of claims 1 to 7, wherein the wax agent is polyethylene wax or a mixed wax of polyethylene wax and paraffin wax.
9. The ink composition according to any one of claims 1 to 8, wherein the wax agent is an aqueous wax emulsion.
10. A method for producing an ink composition according to any one of claims 1 to 9,
    The polymer dispersant is an AB block polymer;
    Copolymerization by a living radical polymerization method using a polymerization initiator to obtain the AB block polymer;
    Preparing a colored dispersion from the colorant and the polymer dispersant; and
    Furthermore, a wax agent and a liquid medium are blended to obtain an ink composition,
    The polymerization initiator is a mixture of an organic tellurium compound represented by the following formula (1) and an organic ditellurium compound represented by the following formula (2), or an organic tellurium compound represented by the following formula (1), azo A system polymerization initiator and a mixture of organic ditellurium compounds represented by the following formula (2):
    The AB block polymer has an A block and a B block,
    The monomer constituting the A block is one or more monomers represented by the following formula (3), and the monomer constituting the B block is benzyl methacrylate and / or benzyl acrylate,
    A method for producing an ink composition.
    

    

    (In the above formula (1), R ₁ represents a C ₁ -C ₈ alkyl group, aryl group, substituted aryl group or aromatic heterocyclic group. R ₂ and R ₃ are a hydrogen atom or C ₁ -C Represents an alkyl group of _8. R ₄ represents an aryl group, a substituted aryl group, an aromatic heterocyclic group, an acyl group, an amide group, an oxycarbonyl group or a cyano group.
    

    

    (In the above formula (2), R ¹ is the same as R ¹ in the above formula (1).)
    

    

    (In the above formula (3), R ₅ represents a hydrogen atom or an alkyl group which may have 4 carbon atoms, and R ₆ represents a hydrogen atom or a methyl group.)
11. The colored dispersion is prepared by adding the colorant to an emulsion obtained by mixing a solution of a hydrophobic organic solvent in which the polymer dispersant is dissolved and a liquid mainly containing water containing a neutralizing agent. The method for producing an ink composition according to claim 10, wherein the ink composition is prepared by adding water and removing the solvent after dispersion.
12. An ink jet recording method for performing recording by ejecting droplets of the ink composition according to any one of claims 1 to 9 in accordance with a recording signal and attaching the droplets to a recording material.
13. 13. The ink jet recording method according to claim 12, wherein the recording material is an information transmission sheet.
14. A colored body colored with the ink composition according to any one of claims 1 to 9.
15. A colored product colored by the ink jet recording method according to claim 12.
16. An ink jet printer loaded with a container containing the ink composition according to any one of claims 1 to 9.