JP2001329199A - Aqueous ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water-based ink composition which exhibits excellent water resistance, excellent abrasion resistance and excellent marker resistance, and further to obtain a water-based ink composition which can suitably be used for water-based ink products having excellent printability and used for ink jet recording. SOLUTION: This water-based ink composition comprises an aqueous medium, a self-dispersing pigment and/or polymer particles A comprising a water- insoluble polymer and a dye or pigment contained in the polymer, and polymer particles B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an aqueous ink composition. More specifically, the present invention relates to an aqueous ink composition that can be used for a water-based ink for ink-jet recording.

[0002]

2. Description of the Related Art An ink jet recording system is a recording system in which ink droplets are directly ejected from a very fine nozzle onto a recording member and adhered to obtain characters and images. According to this method, not only has the advantage that the device to be used has low noise and good operability, but also has the advantage that colorization is easy and plain paper can be used as a recording member. It has been widely used in recent years.

In such an ink jet recording system,
As the ink, those obtained by dissolving various water-soluble dyes in water or a mixture of water and an organic solvent are often used.

However, when a water-soluble dye is used, the light resistance of a recorded image often becomes a problem because the water-soluble dye is originally inferior in light resistance.

[0005] Further, since the ink is water-soluble, water resistance of a recorded image often becomes a problem. That is, when rain, sweat, or water for eating and drinking is applied to the recorded image, the recorded image may be blurred or lost.

[0006] Therefore, in order to improve these problems such as light resistance and water resistance, an ink jet recording system printer using a pigment ink in which a pigment is dispersed using a dispersant has come to market.

However, by using pigment ink,
Although the light resistance and water resistance are remarkably improved, a new problem has arisen that the abrasion resistance of the printed matter, especially the abrasion resistance and the marker resistance, are inferior to those when printed using dye ink. . In particular, when printing is performed with an ink designed to increase the print concentration or increase the pigment concentration, or ink designed to remain on the paper surface without penetrating the pigment, the problem of abrasion resistance of the printed matter is serious. However, there is a problem that printed matter is contaminated by rubbing with an eraser, rubbing strongly with a hand, or rubbing with a marker pen. In addition, the water resistance is much higher than that of the water-soluble dye, but is not sufficiently satisfactory.

Therefore, several proposals have been made for the purpose of improving abrasion resistance and water resistance. JP-A-55-80477, JP-A-62-124167 and the like describe systems containing a water-soluble polymer, and JP-A-3-56573, JP-A-4-18
No. 462 discloses a system in which a polymer emulsion is blended in an ink.

However, a system containing a water-soluble polymer, on the other hand, decreases the water resistance, and if an amount necessary to satisfy the abrasion resistance is added to the ink, the viscosity of the ink increases and the nozzles are clogged. In addition, ejection failure such as deterioration of continuous printability is caused. In addition, a system containing a polymer emulsion may also need to be blended with a large amount of a polymer emulsion in order to exhibit the effect of abrasion resistance and water resistance, probably because the affinity between the polymer emulsion and the pigment dispersion is low. As in the case of the water-soluble polymer, ejection failure is likely to occur.

[0010]

The present invention can be suitably used for an aqueous ink composition exhibiting excellent water resistance, scratch resistance and marker resistance, and further, an aqueous ink for ink jet recording having excellent printability. It is an object to provide an aqueous ink composition.

[0011]

SUMMARY OF THE INVENTION The present invention provides an aqueous medium,
Polymer particles A and / or self-dispersible pigment containing a dye or pigment in a water-insoluble polymer, and polymer particles B
And an aqueous ink composition containing:

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

As the colorant, polymer particles A containing a dye or pigment in a water-insoluble polymer and / or a self-dispersible pigment are used.

The polymer particles A are polymer particles containing a dye or a pigment. On the other hand, the polymer particles B are polymer particles containing no dye and no pigment.

Examples of the polymer of the polymer particles B include vinyl polymers, ester polymers, urethane polymers and the like.

The polymer particles B can be suitably used, for example, as an aqueous dispersion. Examples of the aqueous dispersion of the polymer particles B include a polymer emulsion and a polymer suspension.

The polymer of the polymer particles B has the same hydrophobic monomer as that used for the polymer particles containing the dye or pigment as a constituent component thereof in view of the affinity with the polymer of the polymer particles A. It is preferable that the polymer has the same polymer composition. In the case of combining with a self-dispersible pigment, it is preferable to copolymerize styrene as a hydrophobic monomer in view of the affinity.

The average particle diameter of the polymer particles B is preferably from 0.001 to 0.5 μm from the viewpoint of discharge stability and abrasion resistance. When the average particle diameter is 0.5 μm or less, clogging of the nozzle is unlikely to occur, and when the average particle diameter is 0.001 μm or more, the time required to develop abrasion resistance after printing is short. The average particle size of the polymer particles B is preferably smaller than the average particle size of the colorant from the viewpoint of improving the abrasion resistance with a small amount. The polymer particles B preferably have a film forming property at 25 ° C.

When the polymer B is prepared as an emulsion, an emulsifier may be used for the synthesis, but a surfactant may be used because the surface tension of the resulting aqueous ink composition may be excessively reduced. It is preferable to use a soap-free polymerization or a phase inversion emulsification method. On the other hand, when the ejection property is deteriorated by adding the polymer emulsion, a polyalkoxyalkylene derivative having a surface tension of a 10% aqueous solution of 45 mN / m or more may be contained when synthesizing the polymer emulsion.

It is considered that when a polyalkoxyalkylene derivative is contained, a highly hydrophilic alkoxyalkylene group is localized on the surface of the polymer particles of the polymer emulsion, thereby improving the ejection property.

Examples of the polyalkoxyalkylene derivative include a compound represented by the formula (I): R ¹ O— (CH ₂ CHYO) _a —H (I) (wherein R ¹ contains a hydrogen atom or a heteroatom having 1 to 8 carbon atoms) A saturated or unsaturated monovalent hydrocarbon group; Y is a hydrogen atom or a methyl group; a is a number from 1 to 100), a compound represented by the formula (II): R ² [O- (CH ₂ CHYO) _b -H] _c (II) (wherein, Y is the same as above. R ² is a saturated or unsaturated monovalent hydrocarbon which may contain a heteroatom having 1 to 8 carbon atoms) Group; b represents a number of 1 to 100, c represents a number of 2 to 10)
The compound represented by these is mentioned.

Preferred examples of the compound represented by the formula (I) include monomethoxy, monoethoxy, mono (iso) propoxy, mono (iso) butoxy, monophenoxyethylene oxide-propylene oxide copolymer (ethylene oxide The number of moles of addition = 5 to 30, the number of moles of propylene oxide = 0 to 5).

Preferred examples of the compound represented by the formula (II) include (iso) propylene glycol, di (iso) propylene glycol, (iso) butylene glycol, 1,3-phenylene glycol, 1,4-phenylene Ethylene oxide / propylene oxide copolymer of glycol, glycerin, diglycerin, triglycerin, pentaerythritol, trimethylolethane, trimethylolpropane, α-methylglucoside (moles of ethylene oxide added: 5 to 30, propylene oxide added Number of moles = 0
5) and the like.

The amount of the polyalkoxyalkylene derivative is
For 100 parts by weight of the total solid content of the polymer emulsion,
It is desirable that the content be 90 parts by weight or less, preferably 50 parts by weight or less, and more preferably 30 parts by weight or less. When the amount of the polyalkoxyalkylene derivative exceeds 90 parts by weight, the effect of blending the polymer emulsion is reduced, probably because the affinity with the colorant is reduced.

The amount of the polymer particles B in the aqueous ink composition is not particularly limited as long as it does not impair the ejection property and exhibits water resistance and abrasion resistance. 0.05 to 3% by weight, more preferably 0.1 to
Desirably, it is 2% by weight. When the amount of the polymer particles B is
When the content is 0.01% by weight or more, the effect on water resistance and abrasion resistance is large, and when the content is 15% by weight or less, the dischargeability is excellent.

The polymer particles A in which a dye or pigment is added to a water-insoluble polymer are effective in expressing water and abrasion resistance on printed matter by themselves, but have not yet reached a sufficiently satisfactory level. In some cases, the insufficient performance is supplemented by the polymer particles B. The self-dispersion pigment is very poor in abrasion resistance, but is effective in increasing the print density. Any of these colorants may be selected depending on the purpose, or both may be used in combination.

The dye that can be contained in the polymer particles A is not particularly limited, but a hydrophobic dye is preferred. Examples thereof include oil-based dyes, disperse dyes, and basic dyes. Among these, oil-based dyes and disperse dyes are preferable because they can be favorably contained in the polymer particles A.

The oil-based dye is not particularly limited, but examples thereof include CI Solvent Black 3, 7,
27, 29, 34; CI Solvent Yellow 14, 16, 29, 5
6, 82; CI Solvent Red 1, 3, 8, 18, 24, 2
7, 43, 51, 72, 73; CI Solvent Violet
CI Solvent Blue 2, 11, 70; CI Solvent Green 3, 7; CI Solvent Orange 2, and the like.

The disperse dye is not particularly limited, but preferred examples thereof include CI Disperse Yellow 5, 42, 54, 64, 79, 82, 83, 93, 99, 100, 11
9, 122, 124, 126, 160, 184: 1, 186, 198, 19
9, 204, 224, 237; CI Disperse Orange 1
3, 29, 31: 1, 33, 49, 54, 55, 66, 73, 118, 119, 1
63; CI Disperse Red 54, 60, 72, 73, 86, 8
8, 91, 93, 111, 126, 127, 134, 135, 143, 145
, 152, 153, 154, 159, 164, 167: 1, 177, 181
, 204, 206, 207, 221, 239, 240, 258, 277
, 278, 283, 311, 323, 343, 348, 356, 362
CI Disperse Violet 33; CI Disperse Blue 56, 60, 73, 87, 113, 128, 143, 148
, 154, 158, 165, 165: 1, 165: 2, 176, 183, 1
85, 197, 198, 201, 214, 224, 225, 257, 266
, 267, 287, 354, 358, 365, 368; CI Disperse Green 6: 1, 9 and the like.

From the viewpoint of efficiently encapsulating the hydrophobic dye in the polymer particles A, it is desirable that the dye can be dissolved in an organic solvent in an amount of 2 g / L or more, preferably 20 to 500 g / L.

The pigment that can be contained in the polymer particles A is not particularly limited, and any of known inorganic pigments and organic pigments can be used. If necessary, an extender can be used together with them. Examples of the inorganic pigment include carbon black, metal oxides, metal sulfides, metal chlorides, and the like. In particular, in a black aqueous ink composition, carbon black is preferable. Examples of the carbon black include furnace black, lamp black, acetylene black, and channel black. Examples of the organic pigment include an azo pigment, a diazo pigment, a phthalocyanine pigment, a quinacridone pigment, an isoindolinone pigment, a dioxazine pigment, a perylene pigment, a perinone pigment, a thioindigo pigment, an anthoraquinone pigment, and a quinophthalone pigment. Examples of the extender include silica, calcium carbonate, talc and the like.

The water-insoluble polymer used in the aqueous dispersion of the polymer particles A containing a hydrophobic dye or pigment includes:
Examples include a vinyl polymer, an ester-based polymer, and a urethane-based polymer. Among these polymers, vinyl polymers are preferred.

As the aqueous dispersion of vinyl polymer particles,
(A) a salt-forming group-containing monomer, and (b) a macromer,
(C) An aqueous dispersion of vinyl polymer particles containing a pigment in a vinyl polymer obtained by copolymerizing a monomer mixture containing a monomer having a salt-forming group and a monomer copolymerizable with a macromer, and (a) a salt-forming group Aqueous dispersion of vinyl polymer particles containing pigments in a vinyl polymer obtained by copolymerizing a monomer mixture containing (b) a macromer, (c) a monomer having a salt-forming group and a monomer copolymerizable with the macromer. The body is more preferred.

The component (a) includes a cationic monomer, an anionic monomer and the like.
JP-A-9-286939, page 5, column 7, line 24 to column 8, line 29, and the like can be mentioned.

Representative examples of the cationic monomer include an unsaturated tertiary amine-containing monomer, an unsaturated ammonium salt-containing monomer, and the like. Among these, N, N-dimethylaminoethyl (meth) acrylate, N-
(N ′, N′-dimethylaminopropyl) (meth) acrylamide and vinylpyrrolidone are preferred.

Representative examples of the anionic monomer include unsaturated carboxylic acid monomers, unsaturated sulfonic acid monomers,
Unsaturated phosphate monomers and the like, among these,
Unsaturated carboxylic acid monomers such as acrylic acid and methacrylic acid are preferred.

The component (b) has a number average molecular weight of 500 to 500.
Macromers which are monomers having from 100,000, preferably from 1000 to 10,000 polymerizable unsaturated groups, are mentioned. Among them, formula (III): X ¹ (Y ¹ ) _q Si (R ³ ) _3-r (Z ¹ ) _r (III) (wherein X ¹ is a polymerizable unsaturated group, and Y ¹ is 2 R ³ is independently a hydrogen atom, a lower alkyl group, an aryl group or an alkoxy group, Z ¹ is a residue of a monovalent siloxane polymer having a number average molecular weight of 500 or more, q is 0 or 1 , R represents an integer of 1 to 3), and / or a styrene-based macromer having a polymerizable functional group at one end.

The number average molecular weight of the component (b) is measured by gel chromatography using chloroform containing 1 mmol / L dodecyldimethylamine as a solvent, using polystyrene as a standard substance.

The silicone macromer can be suitably used from the viewpoint of preventing scorching of the head of an ink jet printer.

In the silicone macromer represented by the formula (III), X ¹ represents a CH ₂ ＣＨCH— group and CH ₂ ＝
A monovalent unsaturated hydrocarbon group having 2 to 6 carbon atoms such as a C (CH ₃ ) — group is exemplified. As Y ¹ , a —COO— group, —
A COOC _a1 H _2a1 — group (a ₁ represents an integer of ₁ to 5),
And a divalent linking group such as a phenylene group.
₃ H ₆ -is preferred. R ³ is a hydrogen atom; a lower alkyl group having 1 to 5 carbon atoms such as a methyl group or an ethyl group; an aryl group having 6 to 20 carbon atoms such as a phenyl group; an alkoxy group having 1 to 20 carbon atoms such as a methoxy group; And the like, and among them, a methyl group is preferable. Z ¹ is preferably a monovalent residue of a dimethylsiloxane polymer having a number average molecular weight of 500 to 5,000. q is 0 or 1, but preferably 1. r is an integer of 1 to 3, and is preferably 1.

Representative examples of silicone macromers include:
Formula (III-1): CH ₂ = CR ⁴ —COOC ₃ H ₆ — [Si (R ⁵ ) ₂ —O] _b1 —Si (R ⁵ ) ₃ (III-1) (where R ⁴ is a hydrogen atom Or a methyl group, R ⁵ is each independently a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms,
b ₁ represents a number of 5 to 60), a silicone macromer represented by the formula (III-2): CH ₂ = CR ⁴ —COO— [Si (R ⁵ ) ₂ —O] _b1 —Si (R ⁵ ) ₃ (III-2) (wherein R ⁴ , R ⁵ and b ₁ are the same as above), formula (III-3): CH ₂ = CR ⁴ -Ph- [Si (R ⁵ ) ₂ -O] _b1 -Si (R ⁵ ) ₃ (III-3) (wherein Ph is a phenylene group, R ⁴ , R ⁵ and b ₁ are the same as described above), and a compound represented by the formula (III) -
4): CH ₂ = CR ⁴ —COOC ₃ H ₆ —Si (OE) ₃ (III-4) wherein R ⁴ is the same as above. E is the formula:-[Si (R ⁴ ) ₂ O] _c1-
And a silicone macromer represented by the formula: Si (R ⁴ ) ₃ (R ⁴ is the same as above, and c ₁ represents a number of 5 to 65).

Among them, the silicone macromer represented by the formula (III-1) is preferable, and particularly, the formula (III-1a): CH ₂ = C (CH ₃ ) —COOC ₃ H _6- [Si (CH _{3) 2 -O] d1 -CH 3} (III-1a) ( wherein, d ₁ is preferably silicone macromer represented by the number of 8 to 40). As an example, FM-0711
(Trade name, manufactured by Chisso Corporation).

The styrenic macromer can be suitably used from the viewpoint of sufficiently containing the pigment in the vinyl polymer.

Examples of the styrene-based macromer include a styrene homopolymer having a polymerizable functional group at one terminal or a copolymer of styrene and another monomer. Among these, those having an acryloyloxy group or a methacryloyloxy group as a polymerizable functional group at one end are preferable. From the viewpoint of ensuring that the pigment is sufficiently contained in the vinyl polymer, the styrene content in the copolymer is 60%.
It is desirable that the content be at least 70% by weight, preferably at least 70% by weight. Examples of the other monomer include acrylonitrile.

As the component (c), methyl (meth) acrylate, ethyl (meth) acrylate, (iso) propyl (meth) acrylate, (iso or tertiary)
Butyl (meth) acrylate, (iso) amyl (meth)
Acrylate, cyclohexyl (meth) acrylate,
Benzyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (iso) octyl (meth) acrylate, (iso) decyl (meth) acrylate, (iso) dodecyl (meth) acrylate, (iso) stearyl (meth) acrylate (Meth) acrylates; styrene-based monomers such as styrene, vinyltoluene, 2-methylstyrene, and chlorostyrene; and the like, and these can be used alone or in combination of two or more. The above (iso or tertiary) and (iso) mean both the case where these groups are present and the case where they are not present, and indicate normal when these groups are not present.

The component (c) preferably contains a styrene monomer from the viewpoint of improving the printing density and the marker resistance. As the styrene monomer, styrene and 2-methylstyrene are preferable, and these may be used alone or in combination. In this case, the content of the styrene monomer in the component (c) is preferably from 10 to 100% by weight, and more preferably from 40 to 100% by weight, from the viewpoint of improving the printing density and the marker resistance.

The monomer mixture comprises (d) a hydroxyl group-containing monomer (hereinafter referred to as “component (d)”) and (e) a compound represented by the formula (I)
V): CH ₂ ＣC (R ⁶ ) COO (R ⁷ O) _p R ⁸ (IV) (wherein, R ⁶ is a hydrogen atom or a lower alkyl group, and R ⁷ is a carbon atom which may have a hetero atom. A divalent hydrocarbon group having 1 to 30 carbon atoms, R ⁸ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 30 carbon atoms which may have a hetero atom, and p represents a number of 1 to 60 ) May be contained in the composition of the present invention (hereinafter, referred to as component (e)).

As the component (d), 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, polyethylene glycol (n = 2 to 2)
30) (meth) acrylate, poly (ethylene glycol (n = 1 to 15) propylene glycol (n = 1 to 1)
5)) (meth) acrylate and the like. Among them, 2-hydroxyethyl (meth) acrylate is preferred.

The component (e) exhibits an excellent effect of improving the ejection stability of the aqueous ink composition of the present invention and suppressing the occurrence of warpage even in continuous printing.

In the formula (IV), R ⁶ is a hydrogen atom or a lower alkyl group. As the lower alkyl group, one having 1 carbon atom
To 4 alkyl groups.

R ⁷ is a divalent hydrocarbon group having 1 to 30 carbon atoms which may have a hetero atom. Examples of the hetero atom include a nitrogen atom, an oxygen atom, a halogen atom and a sulfur atom.

Representative examples of R ⁷ include an aromatic ring having 6 to 30 carbon atoms which may have a substituent, a heterocyclic ring having 3 to 30 carbon atoms which may have a substituent and a substituent. And an alkylene group having 1 to 30 carbon atoms which may have a ring, and these rings or groups may be a combination of two or more kinds. Examples of the substituent include an aromatic ring having 6 to 29 carbon atoms, a heterocyclic ring having 3 to 29 carbon atoms, an alkyl group having 1 to 29 carbon atoms, a halogen atom, and an amino group.

Preferable examples of R ⁷ include a phenylene group which may have a substituent having 1 to 24 carbon atoms, and a C 1 to 3 carbon atom.
0, preferably an aliphatic alkylene group having 1 to 20 carbon atoms, an alkylene group having 7 to 30 carbon atoms having an aromatic ring, and an alkylene group having 4 to 30 carbon atoms having a hetero ring.

Preferable examples of the R ⁷ O group include an ethylene oxide group, an (iso) propylene oxide group,
C2-C7 comprising a tetramethylene oxide group, a heptamethylene oxide group, a hexamethylene oxide group, and a combination of at least one of these alkylene oxides
Alkylene oxide group and phenylene oxide group.

R ⁸ is a monovalent hydrocarbon group having 1 to 30 carbon atoms which may have a hetero atom. Examples of the hetero atom include a nitrogen atom, an oxygen atom and a sulfur atom.

Typical examples of R ⁸ include an aromatic ring having 6 to 30 carbon atoms which may have a substituent, a heterocyclic ring having 3 to 30 carbon atoms which may have a substituent, Examples thereof include an alkyl group having 1 to 30 carbon atoms which may have a group. Examples of the substituent include an aromatic ring having 6 to 29 carbon atoms, a hetero ring having 4 to 29 carbon atoms, a halogen atom, and an amino group.

Preferred examples of R ⁸ include a phenyl group, an aliphatic alkyl group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, an alkyl group having 7 to 30 carbon atoms having an aromatic ring, and a heterocyclic ring. And an alkyl group having 4 to 30 carbon atoms having the formula:

More preferred examples of R ⁸ include a methyl group,
Ethyl group, (iso) propyl group, (iso) butyl group,
1 carbon atom such as (iso) pentyl group and (iso) hexyl group
To 6 alkyl groups, phenyl groups and the like. p is 1
The number is preferably from 60 to 60, and more preferably from 1 to 30.

Specific examples of the component (e) include methoxypolyethylene glycol (1 to 30: the value of p in the formula (IV); the same applies hereinafter) (meth) acrylate, methoxypolytetramethylene glycol (1 to 30) ) (Meth) acrylate, ethoxy polyethylene glycol (1-30) (meth) acrylate, (iso) propoxy polyethylene glycol (1-30) (meth) acrylate, butoxy polyethylene glycol (1-30) (meth) acrylate, methoxy polypropylene Glycol (1-30) (meth) acrylate, methoxy (ethylene glycol / propylene glycol copolymer) (1-30, ethylene glycol in it: 1-29) (meth) acrylate, and the like. Alternatively, two or more kinds can be used as a mixture. Of these, methoxypolyethylene glycol (1-30) (meth) acrylate is preferred. In addition, "(meth) acrylate" in this specification shows acrylate or methacrylate. “(Iso) propoxy” indicates n-propoxy or isopropoxy.

The content of the component (a) in the vinyl polymer is desirably 1 to 40% by weight, preferably 2 to 40% by weight, from the viewpoint of dispersion stability of the resulting dispersion.

The content of the component (b) in the vinyl polymer is from 1 to 25% by weight from the viewpoint of suppressing the scorching of the heater surface of the ink jet printer and the stability.
Preferably, the content is 5 to 20% by weight.

The content of the component (c) in the vinyl polymer is from 5 to 93% by weight from the viewpoint of suppressing the scorching of the heater surface of the ink jet printer and the stability.
Preferably, it is 10 to 80% by weight. When the component (c) containing a styrene monomer is used, the content of the component (c) in the vinyl polymer is preferably from 10 to 60% by weight.

The content of the component (d) in the vinyl polymer is desirably 5 to 40% by weight, preferably 7 to 20% by weight, from the viewpoints of ejection stability and print density. (A)
The total content of the component and the component (d) is desirably 6 to 60% by weight, preferably 10 to 50% by weight, from the viewpoint of stability in water and water resistance.

The content of the component (e) in the vinyl polymer is desirably 5 to 50% by weight, preferably 10 to 40% by weight, from the viewpoint of ejection stability and dispersion stability.

The total content of the component (a) and the component (e) in the vinyl polymer is preferably 6 to 75% by weight from the viewpoint of dispersion stability in water and discharge stability.

The total content of the component (a), the component (d) and the component (e) in the vinyl polymer is from 6 to 60% by weight, preferably from the viewpoint of dispersion stability in water and discharge stability. 7 to 50% by weight is desirable.

The vinyl polymer can be prepared by known polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization.
It is produced by copolymerizing a monomer mixture. Among these polymerization methods, a solution polymerization method is preferable.

The solvent used in the solution polymerization method is preferably a polar organic solvent, and a water-miscible organic solvent can be used by mixing with water. Examples of the organic solvent include aliphatic alcohols having 1 to 3 carbon atoms such as methanol, ethanol, and propanol; ketones such as acetone and methyl ethyl ketone; and esters such as ethyl acetate. Among them, methanol, ethanol, acetone, methyl ethyl ketone or a mixed solution of these with water is preferable.

At the time of polymerization, a radical polymerization initiator can be used. As the radical polymerization initiator,
2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl-2,2′-azobisbutyrate, 2,2′-azobis (2-methyl Azo compounds such as butyronitrile) and 1,1'-azobis (1-cyclohexanecarbonitrile) are preferred. Further, organic peroxides such as t-butyl peroxyoctoate, di-t-butyl peroxide and dibenzoyl oxide can also be used.

The amount of the polymerization initiator is preferably from 0.001 to 5 mol%, particularly preferably from 0.01 to 2 mol%, based on the monomer mixture.

In the polymerization, a polymerization chain transfer agent may be further added. Specific examples of the polymerization chain transfer agent include mercaptans such as octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-tetradecyl mercaptan, and mercaptoethanol;
Xanthogen disulfides such as dimethylxanthogen disulfide and diisopropylxanthogen disulfide; thiuram disulfides such as tetramethylthiuram disulfide and tetrabutylthiuram disulfide; halogenated hydrocarbons such as carbon tetrachloride and ethylene bromide; hydrocarbons such as pentaphenylethane And acrolein, methacrolein, allyl alcohol, 2-ethylhexylthioglycolate, turbinolene, α-terpinene, γ-terpinene, dipentene, α-methylstyrene dimer, and further 9,10-dihydroanthracene;
Unsaturated cyclic hydrocarbon compounds such as 1,4-dihydronaphthalene, indene, and 1,4-cyclohexadiene; 2,5
-Unsaturated heterocyclic compounds such as dihydrofuran and the like, and these can be used alone or in combination of two or more.

The polymerization conditions for the monomer mixture vary depending on the type of radical polymerization initiator, monomer and solvent used, but the polymerization temperature is usually 30 to 100 ° C., preferably 50 to 100 ° C.
80 ° C. and the polymerization time is 1 to 20 hours. The polymerization atmosphere is preferably an inert gas atmosphere such as a nitrogen gas.

After completion of the polymerization reaction, reprecipitation from the reaction solution
The copolymer can be isolated by a known method such as solvent evaporation. The obtained copolymer can be purified by repeating reprecipitation or removing unreacted monomers and the like by membrane separation, chromatographic method, extraction method and the like.

The hydrophobic monomers used for the polymer of the polymer particles A and the polymer of the polymer particles B containing the dye or the pigment are the components (b) and (c).

The weight average molecular weight of the polymer is 3000 to 1000
The value of 00 is preferable from the viewpoint of durability after printing and dispersion stability.

The aqueous dispersion of the polymer particles A containing the hydrophobic dye can be produced by a known emulsification method. For example, a polymer and a hydrophobic dye are dissolved in an organic solvent, a neutralizing agent is added as needed to ionize a salt-forming group in the polymer, and water is added thereto. By emulsifying the mixture with an organic solvent, distilling off the organic solvent, and inverting the phase to an aqueous phase.

As a method for obtaining an aqueous dispersion of the polymer particles A containing the pigment, a polymer is dissolved in an organic solvent, and a pigment, water, a neutralizing agent and, if necessary, a surfactant are added and kneaded to form a paste. After that, a method is preferred in which the paste is diluted with water as necessary, and the organic solvent is distilled off to make the paste aqueous.

The amount of the hydrophobic dye or pigment in the polymer particles A is preferably from 20 to 400 parts by weight based on 100 parts by weight of the solid content of the polymer in view of the printing density and the ease of inclusion in the polymer particles. .

Examples of the self-dispersing pigment include, for example, Cabo-Jet 200 commercially available from Cabot.
Self-dispersible carbon black obtained by dispersing and stabilizing carbon black such as (trade name) without a dispersant.

The particle size of the polymer particles containing these dyes or pigments and the pigment of the pigment dispersion is preferably from 10 to 500 nm from the viewpoint of dispersion stability.

The content of the coloring agent in the aqueous ink composition is not particularly limited as long as a sufficient printing density can be obtained. Usually, the content is from 1 to 30% by weight, preferably from 2 to 30% by weight, from the viewpoint of providing sufficient ejection properties and print density.
It is 10% by weight, more preferably 4 to 8% by weight.

The aqueous ink composition of the present invention may contain various known additives such as wetting agents such as polyhydric alcohols, dispersants, defoamers, fungicides and / or chelating agents, and pH regulators. Can be added.

[0083]

EXAMPLES Preparation Example 1 [Preparation of aqueous dispersion of polymer particles containing colorant: carbon black or hydrophobic dye] (1) Preparation of water-insoluble polymer (1-1) Preparation of anionic polymer solution Mechanical stirrer After thoroughly replacing the inside of a 1 L flask equipped with a thermometer, a nitrogen gas inlet tube, a reflux tube and a dropping funnel with nitrogen gas, 11.2 g of styrene, 2.8 g of acrylic acid, 10.0 g of lauryl methacrylate, 10.0 g of methoxypolyethylene glycol (n = 9) 4.0 g of methacrylate, 4.0 g of styrene macromer (trade name: AS-6, manufactured by Toagosei Co., Ltd.), silicon macromer (trade name: FM-0711, manufactured by Chisso Corporation) and 0.4 g of mercaptoethanol , To 65 ° C.

Next, 100.8 g of styrene and 25.2 g of acrylic acid
, Lauryl methacrylate 100.0 g, methoxypolyethylene glycol (n = 9) methacrylate 36.0 g, hydroxyethyl methacrylate 60.0 g, styrene macromer (manufactured by Toagosei Co., Ltd., trade name: AS-6) 36.0 g, silicon macromer (Chisso Corporation ), Product name: FM-0711) 8.0g,
A mixed solution of 3.6 g of mercaptoethanol, 2.4 g of azobisdimethylvaleronitrile and 18 g of methyl ethyl ketone was added to 2.
It was dropped into the flask over 5 hours.

After completion of the dropwise addition, a mixed solution of 0.8 g of azobisdimethyl valeronitrile and 18 g of methyl ethyl ketone was added to 0.5 g of a mixed solution.
It was dropped into the flask over time. After aging for 1 hour at 65 ° C, 0.8 g of azobisdimethylvaleronitrile was added,
Aged for an additional hour.

After completion of the reaction, 364 g of methyl ethyl ketone was added to the flask to obtain 800 g of a 50% polymer solution.

A part of the obtained copolymer solution was removed under reduced pressure.
It was dried at 105 ° C. for 2 hours, isolated by removing the solvent, polystyrene as a standard substance, and 1 mm as a solvent.
The weight-average molecular weight measured by gel permeation chromatography using chloroform containing ol / L dodecyldimethylamine was 28,000.

(1-2) Preparation of Cationic Polymer Solution A 1-L flask equipped with a mechanical stirrer, a thermometer, a nitrogen gas inlet tube, a reflux tube, and a dropping funnel was sufficiently purged with nitrogen gas. g, lauryl methacrylate 1
2.0 g, N, N-dimethylaminoethyl methacrylate
40.0 g, methoxypolyethylene glycol (n = 4) methacrylate 60.0 g, styrene macromer (Toagosei Co., Ltd.)
Product name: AS-6) 20.0 g and mercaptoethanol 0.
8 g was charged and the temperature was raised to 65 ° C.

Next, 40.0 g of styrene, 20.0 g of lauryl methacrylate, 60.0 g of N, N-dimethylaminoethyl methacrylate, methoxypolyethylene glycol (n = 4)
A mixed solution of 70.0 g of methacrylate, 20.0 g of styrene macromer (trade name: AS-6, manufactured by Toa Gosei Co., Ltd.), 7.2 g of mercaptoethanol, 2.4 g of azobisdimethyl valeronitrile and 18 g of methyl ethyl ketone was placed in the flask over 2.5 hours. It was dropped.

After completion of the dropwise addition, a mixed solution of 0.8 g of azobisdimethylvaleronitrile and 18 g of methyl ethyl ketone was added to 0.5 g of a mixed solution.
It was dropped into the flask over time. After aging for 1 hour at 65 ° C, 0.8 g of azobisdimethylvaleronitrile was added,
Aged for an additional hour.

After completion of the reaction, 364 g of methyl ethyl ketone was added to the flask to obtain 800 g of a 50% concentration polymer solution.

A part of the obtained copolymer solution was removed under reduced pressure.
It was dried at 105 ° C. for 2 hours, isolated by removing the solvent, and the weight average molecular weight was measured by gel permeation chromatography using polystyrene as a standard substance and tetrahydrofuran as a solvent.
000.

(2) Preparation of Aqueous Dispersion of Carbon Black-Containing Polymer Particles (2-1) Anionic Carbon Black-Containing Polymer Particles 28 g of the polymer solution obtained in the above (1-1), carbon black (Cabot (Cabot)) (Product name: Monarch880)
After sufficiently stirring 26 g, 13.6 g of a 1 mol / L aqueous potassium hydroxide solution, 20 g of methyl ethyl ketone and 30 g of ion-exchanged water, 20 times using a three-roll mill (trade name: NR-84A, manufactured by Noritake Co., Ltd.). Kneaded.

The obtained paste was put into 200 g of ion-exchanged water, and after sufficiently stirring, methyl ethyl ketone and water were distilled off using an evaporator, and the solid content was 20.0% by weight.
160 g of an aqueous dispersion of anionic carbon black-containing polymer particles was obtained. The average particle size of the polymer particles was 110 nm as a result of measurement using a Coulter counter N4 (trade name, manufactured by Coulter Corporation).

(2-2) Cationic Carbon Black-Containing Polymer Particles 28 g of the polymer solution obtained in the above (1-2), carbon black (trade name: Monarch880, manufactured by Cabot)
20 g, 1 mol / L acetic acid aqueous solution 11.1 g, methyl ethyl ketone
After sufficiently stirring 20 g and 30 g of ion-exchanged water, a three-roll mill [manufactured by Noritake Co., Ltd., trade name: NR-8]
4A] and kneaded 20 times.

The obtained paste was poured into 200 g of ion-exchanged water, and after sufficiently stirring, methyl ethyl ketone and water were distilled off using an evaporator, and the solid content was 20.0% by weight.
160 g of an aqueous dispersion of cationic carbon black-containing polymer particles was obtained. The average particle size of the polymer particles was 138 nm as measured by using a Coulter counter N4 (trade name, manufactured by Coulter Corporation).

(3) Preparation of Aqueous Dispersion of Hydrophobic Dye-Containing Polymer Particles To 28 g of the polymer solution obtained in the above (1-1), 20 g of methyl ethyl ketone and 10 g of Oil Black 860 (manufactured by Orient Co., Ltd.) were added. Dissolve completely, 1 mol in it
/ L potassium hydroxide aqueous solution (13.6 g) was added to neutralize the salt-forming groups of the polymer, and ion-exchanged water (200 g) was added thereto. After stirring, the mixture was stirred for 30 minutes using a microfluidizer (Microfluidizer). Dispersed for minutes.

The organic solvent was removed from the obtained dispersion under reduced pressure at 60 ° C., and the water was further removed to concentrate the dispersion, thereby obtaining an aqueous dispersion of dye-containing polymer particles having a solid content of 20% by weight. . The average particle size of the polymer particles was 82 nm as a result of measurement using a Coulter counter N4 (trade name, manufactured by Coulter Corporation).

Preparation Example 2 [Preparation of polymer emulsion] (A) Anionic polymer emulsion To 28 g of the polymer solution obtained in the above (1-1), 50 g of methyl ethyl ketone was added, and a 1 mol / L potassium hydroxide aqueous solution was added thereto. 13.6 g was added to neutralize the salt-forming groups of the polymer, and 200 g of ion-exchanged water was added thereto. After stirring, the mixture was emulsified for 30 minutes using a microfluidizer (manufactured by Microfluidizer).

The obtained emulsion was concentrated under reduced pressure by removing the organic solvent at 60 ° C. and further removing water to obtain an anionic polymer emulsion having a solid content of 20% by weight. The average particle size of the polymer emulsion was 70 nm as a result of measurement using Coulter Counter N4 (trade name, manufactured by Coulter Corporation).

(B-1) Cationic polymer emulsion 50 g of methyl ethyl ketone was added to 28 g of the polymer solution obtained in the above (1-2), and a 1 mol / L acetic acid aqueous solution of 11.1 was added.
g was added to neutralize the salt-forming groups of the polymer, and 200 g of ion-exchanged water was added thereto, followed by stirring and emulsification using a microfluidizer (manufactured by Microfluidizer) for 30 minutes.

The organic solvent was removed from the obtained emulsion under reduced pressure at 60 ° C., and further concentrated by removing water to obtain a cationic polymer emulsion having a solid content of 20% by weight. The average particle size of the polymer emulsion was 103 nm as a result of measurement using Coulter Counter N4 (trade name, manufactured by Coulter Corporation).

(B-2) Cationic Polymer Emulsion A 50% methyl ethyl ketone solution of monophenoxypolyethylene glycol (ethylene oxide addition mol = 22, surface tension 55 mN / m) was added to 28 g of the polymer solution obtained in the above (1-2). 7 g was added thereto, and 11.1 g of a 1 mol / L acetic acid aqueous solution was added thereto to neutralize the salt-forming groups of the polymer.
After adding 200 g and stirring, the mixture was emulsified for 30 minutes using a microfluidizer (manufactured by Microfluidizer). The surface tension was measured at 25 ° C using a CBVP-Z surface tensiometer prepared by Kyowa Interface Co., Ltd. by preparing a 10 wt% solution with ion-exchanged water.
Was measured.

The organic solvent was removed from the obtained emulsion at 60 ° C. under reduced pressure, followed by removing water to obtain a cationic polymer emulsion having a solid content of 20% by weight. The average particle size of the polymer emulsion was 52 nm as a result of measurement using Coulter Counter N4 (trade name, manufactured by Coulter Corporation).

Example 1 10 g of 2-pyrrolidone, 4 g of glycerin, 5 g of polyethylene glycol (Mw = 1000), 1 g of isopropanol and 42 g of ion-exchanged water were mixed, and the resulting mixture was used as a colorant (2-1). 30 g of an aqueous dispersion of the anionic carbon black-containing polymer particles obtained in the preparation example and 8 g of the anionic polymer emulsion obtained in the preparation example (A) as a polymer emulsion were added with stirring. The obtained mixture is subjected to a membrane filter having an average pore diameter of 0.8 μm (trade name: disk capsule CALC80, manufactured by Fuji Photo Film Co., Ltd.).
To obtain an aqueous ink composition.

Example 2 In Example 1, 30 g of an aqueous dispersion of the cationic carbon black-containing polymer particles obtained in Preparation Example (2-2) was used as a coloring agent, and a polymer emulsion was obtained in Preparation Example (B-1). An aqueous ink composition was obtained in the same manner as in Example 1, except that 5 g of the obtained cationic polymer emulsion was used.

Example 3 In Example 1, 30 g of the cationic carbon black obtained in Preparation Example (2-2) as a colorant and 10 g of the cationic polymer emulsion obtained in Preparation Example (B-2) as a polymer emulsion A water-based ink composition was obtained in the same manner as in Example 1 except for using.

Example 4 In Example 1, (g) 30 g of an aqueous dispersion of the dye-containing polymer particles obtained in the preparation example were used as the colorant, and 1 g of the anionic polymer emulsion obtained in the preparation example (A) was used as the polymer emulsion. A water-based ink composition was obtained in the same manner as in Example 1 except for using.

Example 5 In Example 1, a self-dispersing carbon black (trade name: Cabo-Jet 200, manufactured by Cabot Corp., 20%
An aqueous ink composition was obtained in the same manner as in Example 1, except that 20 g of the aqueous dispersion) and 20 g of the anionic polymer emulsion obtained in Preparation Example (A) were used as the polymer emulsion.

Comparative Example 1 An aqueous ink composition was obtained in the same manner as in Example 1, except that the polymer emulsion was not used.

Comparative Example 2 In Example 1, a self-dispersible carbon black (trade name: Cabo-Jet 200, manufactured by Cabot Corporation, 20%
Aqueous ink composition was obtained in the same manner as in Example 1 except that 20 g of (aqueous dispersion) and no polymer emulsion were used.

Next, as the performance of the aqueous ink compositions obtained in each of the examples and comparative examples, printability (dischargeability), water resistance, scratch resistance and marker resistance were examined based on the following methods. Was. Table 1 shows the results.

[Printability] After filling an aqueous ink composition into an ink jet printer (Hewlett-Packard, trade name: Desk Jet720C),
Plain paper [Xerox, product name: 4024 DP 20l
b.Paper], 10 sheets of A4 solid print were prepared by continuous printing, and then a test document including a text, a solid pattern, and ruled lines was printed, and printability (ejection stability) was evaluated. The evaluation criteria are as follows.

(Evaluation Criteria) シ ャ ー プ: Sharp and clear characters, uniform solid printing,
And all three items of ruled line printing without distortion are satisfied. ○: Sharp and clear characters, uniform solid printing,
And when almost all three items of ruled line printing without distortion are satisfied. Δ: Sharp and clear characters, uniform solid printing,
When one item is not satisfied among unprinted ruled line printing and X: sharp and clear characters, uniform solid printing,
If two or more items are not satisfied in the ruled line printing without distortion

[Water resistance] After performing solid printing using the printer and plain paper used for examining the [printing property] and drying the sample at 25 ° C. for 10 minutes, the print density of a specific printing location was measured. Then, it was immersed in still water for 10 seconds and pulled up as it was. After air drying at 25 ° C for 24 hours, the print density at the same place as before the immersion is measured, and the residual ratio of the print density after the immersion to the print density before the immersion is expressed by the formula: [Residual rate] = [Print after the immersion] Density] / [print density before immersion] × 100, and the water resistance was evaluated based on the following evaluation criteria.

(Evaluation criteria) ：: Residual rate 95% or more ：: Residual rate 90% or more and less than 95% △: Residual rate 70% or more and less than 90% ×: Residual rate less than 70%

[Scratch resistance] Text printing was performed using the printer and plain paper used for examining the above [Printability], and after 6 hours at 25 ° C, the recorded image was placed on 2 cm square cotton wool with a load of 500 g. And then repeatedly rubbed, the number of times of friction until the image was stained (disordered) was visually observed, and evaluated based on the following evaluation criteria.

(Evaluation Criteria) A: There is no stain even after rubbing 20 times. ：: Stain occurs during rubbing 10 to 19 times. There is no practical problem. Δ: Stain occurs during rubbing 5 to 9 times. X: Stain occurs during rubbing 1 to 4 times.

[Marker resistance] Using the printer and plain paper used for examining the [printing property], text printing was performed, and after 6 hours at 25 ° C, the recorded image was transferred to a commercially available aqueous fluorescent pen (manufactured by PILOT). (Spotliter), the degree of contamination of the image was visually observed, and evaluated based on the following evaluation criteria.

(Evaluation Criteria) A: There is no stain such as tailing even when tracing with a highlighter pen. ：: Traces slightly when traced with a highlighter pen, but at a level that is practically acceptable. Δ: Some traces occur when traced with a highlighter pen. ×: When traced with a highlighter pen, tailing occurred and dirt was severe.

[0121]

[Table 1]

From the results shown in Table 1, the aqueous ink compositions obtained in Examples 1 to 5 were superior to those obtained in Comparative Examples 1 and 2 in terms of excellent printability and water resistance. It turns out that it shows scratch resistance and marker resistance.

[0123]

The aqueous ink composition of the present invention exhibits excellent water resistance, abrasion resistance and marker resistance, and exhibits excellent printability (dischargeability) when used in an aqueous ink for ink jet recording. Have

Continued on the front page F-term (reference) 2C056 EA13 FC01 FC02 2H086 BA53 BA55 BA59 BA60 4J037 AA02 AA08 AA10 AA18 CC13 CC16 CC28 DD05 EE03 EE28 EE35 FF18 FF25 4J039 AD03 AD09 AD10 AD20 AD22 AE04 AE07 BA04 BA10 BA13 BC BC17 BC39 BC60 BE01 BE05 BE07 BE08 CA06 EA15 EA16 EA17 EA19 EA20 EA21 EA36 EA38 EA42 EA44 GA24

Claims (6)

[Claims] 1. An aqueous ink composition comprising: an aqueous medium; polymer particles A and / or self-dispersible pigment containing a dye or pigment in a water-insoluble polymer; and polymer particles B. 2. The aqueous ink composition according to claim 1, wherein the hydrophobic monomer used for the polymer of the polymer particles A and the hydrophobic monomer used for the polymer of the polymer particles B are the same. 3. The aqueous ink composition according to claim 1, wherein the composition of the polymer of the polymer particles A and the polymer of the polymer particles B are the same. 4. An average particle diameter of the polymer particles B is smaller than an average particle diameter of the polymer particles A and / or the self-dispersion type pigment in which a dye or a pigment is contained in a water-insoluble polymer. Or an aqueous ink composition as described above. 5. The aqueous ink composition according to claim 1, wherein a polyalkoxyalkylene derivative having a surface tension of 45 mN / m or more is used when producing the polymer particles B. 6. A polymer insoluble in water, comprising: (a) a monomer having a salt-forming group, (b) a macromer, and (c) a monomer mixture containing a monomer having a salt-forming group and a monomer copolymerizable with the macromer. The aqueous ink composition according to any one of claims 1 to 5, which is a vinyl polymer obtained by polymerization.