JP2003192964A - Ink composition - Google Patents

Abstract

(57) [Problem] To provide an ink composition capable of obtaining a recorded matter excellent in abrasion resistance and scratch resistance. The ink composition comprises an ethylenically unsaturated carboxylic acid monomer and another monomer copolymerizable therewith in the presence of a water-soluble polymer compound containing an alcoholic hydroxyl group or a copolymerizable surfactant. The acid value obtained by polymerization under
Zero or more copolymers include a resin whose pH is adjusted with an inorganic base, water, a colorant, and a polyether-modified organosiloxane represented by the following formula (1). Embedded image (1) (In the above formula, R ^{1 to} R ⁹ independently represent a C _1-6 alkyl group or an aryl group, j and k independently represent an integer of 0 or more, and EO represents an ethyleneoxy group. Represents
PO represents a propyleneoxy group, m and n each represent an integer of 0 or more, provided that m + n represents an integer of 1 or more;
O and PO may be in any order within [] and may be random or blocks. )

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink composition, and more particularly to a water-based pigment ink composition suitable for printing on a dedicated paper for ink jet recording. According to the ink composition of the present invention, it is possible to improve the scratch resistance and scratch resistance of a recorded image printed on a dedicated paper for inkjet recording.

[0002]

2. Description of the Related Art An ink jet recording method is a printing method in which ink droplets are ejected and adhered to a recording medium such as paper for printing. In recent years, due to the innovative progress of inkjet recording technology, inkjet recording methods have been used even in the field of high-definition printing, which has been realized only by silver halide photography and offset printing. Along with this, an inkjet recording medium having high gloss comparable to photographic paper, art paper, etc. used in the field of silver salt photography and offset printing has been developed. As a recording medium for such a high-gloss inkjet recording method, a recording medium in which an ink receiving layer containing a porous pigment such as silica is provided on a base material such as paper or film is predominant.

The ink used for recording characters and / or images on the recording medium for the high-gloss ink jet recording method contains water as a main component, a coloring material, a resin emulsion and various other additives. A water-based ink containing the ink is generally used. As the coloring material, dyes or pigments can be used, but light resistance, gas resistance, water resistance,
Since pigments are excellent in terms of weather resistance such as humidity resistance and the like, the demand thereof has been increasing in recent years, and development of pigment inks utilizing the characteristics of pigments has been promoted. Further, an aqueous pigment ink containing a resin emulsion is used in order to improve the fixing property of the pigment on the recording medium.

In the ink jet recording method in which the ink jet recording paper having the ink receiving layer as described above is used as the recording medium and the resin emulsion-containing water-based pigment ink composition as described above is used as the ink, the demand for the image quality is also high. Is becoming more sophisticated. For example, there is an increasing demand for fixability of printed images on the above-mentioned special paper, and a high level of abrasion resistance and scratch resistance is required. That is, in the dedicated paper as described above, the ink receiving layer absorbs the solvent component,
The pigment particles and the polymer particles of the resin emulsion are left on the surface of the recording medium. On the surface of the recording medium, since the solvent component decreases, the density of the polymer particles increases, and the film forming reaction by the polymer particles proceeds to form a film, and the film fixes the pigment on the surface of the recording medium. However, in the conventional pigment ink for inkjet recording,
Although a certain degree of fixing property was obtained, it was insufficient from the viewpoint of scratch resistance and scratch resistance.

An ink composition containing a water-soluble resin has also been proposed for the above-mentioned ink jet recording. For example, JP-A-4-18467 discloses an aqueous ink containing a specific carbon black and a water-soluble resin having an acid value of 100 or more and a weight average molecular weight of 3,000 to 7,000 in an aqueous medium. There is. This water-based ink has the advantage that precipitates are unlikely to occur even when stored for a long period of time, but not only the dot reproducibility of the obtained image is poor, but also the abrasion resistance is poor. Further, in JP-A-7-70254, a high acid value obtained by copolymerizing 21 to 99% by weight of an ethylenically unsaturated carboxylic acid monomer with another monomer in the presence of polyvinyl alcohol is disclosed. A water-soluble resin obtained by neutralizing the copolymer of (1) with a basic compound is described. A water-based ink composed of this water-soluble resin and a colorant,
There is a drawback that the viscosity change during long-term storage is large and the obtained image has poor abrasion resistance.

On the other hand, a modified polysiloxane compound is known as one of silicon-based surface conditioners. Some ink compositions containing this compound are also known. For example, JP-A-59-66475 discloses an ink composition for lithographic printing containing an organo-modified polysiloxane. Further, JP-A-60-173068 discloses an ink composition containing a modified polysiloxane as a defoaming agent. JP-A-5-169790 and JP-A-10-310732 disclose ink compositions for ink jet recording containing a modified polysiloxane having a specific structure. further,
JP-A-10-279871 discloses a dye-based ink composition containing a polyether-modified polysiloxane.

[0007]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention The present inventor has found that in the resin emulsion-containing aqueous pigment ink composition as described above, various characteristics required for the ink composition for an ink jet recording method (for example, ejection stability, Storage stability,
We conducted extensive research into means for improving the abrasion resistance and scratch resistance of the above-mentioned special paper while maintaining the weather resistance and color development), and found that a specific resin and a polyether-modified organosiloxane were used together. It has been found that the above-mentioned problems can be solved by incorporating it in the ink composition.

The present invention is based on these findings.

[0009]

Therefore, in the present invention, an ethylenically unsaturated carboxylic acid monomer and another monomer copolymerizable therewith are used as an alcoholic hydroxyl group-containing water-soluble polymer compound or copolymer. Of a copolymer having an acid value of 40 or less obtained by polymerizing in the presence of a hydrophilic surfactant, a resin whose pH is adjusted by an inorganic base, water, a colorant, and the following formula (1). And a polyether-modified organosiloxane according to the present invention.

[0010]

[Chemical 2] (1) (In the above formula, R ^{1 to} R ⁹ independently represent a C _1-6 alkyl group or an aryl group, j and k each independently represent an integer of 0 or more, and EO represents an ethyleneoxy group. Represents PO
Represents a propyleneoxy group, m and n represent an integer of 0 or more, provided that m + n represents an integer of 1 or more, and EO and PO are in random blocks regardless of their order in []. May be ) According to another preferred aspect of the present invention, the colorant is a pigment.

According to still another preferred embodiment of the present invention,
The inorganic base used to prepare the resin is an alkali metal hydroxide or an alkaline earth metal hydroxide.

According to yet another preferred embodiment of the present invention,
The alcoholic hydroxyl group-containing water-soluble polymer compound used in the preparation of the resin is a vinyl alcohol polymer.

According to yet another preferred embodiment of the present invention,
The ethylenically unsaturated carboxylic acid monomer used to prepare the resin is acrylic acid or methacrylic acid.

According to still another preferred embodiment of the present invention,
The monomer copolymerizable with the ethylenically unsaturated carboxylic acid monomer used for preparing the resin is an ethylenically unsaturated carboxylic acid ester monomer.

According to yet another preferred embodiment of the present invention,
The pH of the resin is 8 to 11 (more preferably 9 to 1).
0).

The ink composition of the present invention is preferably for ink jet recording.

In the present invention, the ink composition is used, and the resin, the colorant, and the polyether-modified organosiloxane contained in the ink composition are substantially left on the surface. The present invention also relates to a method for recording on a recording medium that substantially absorbs the liquid component.

Furthermore, the present invention uses the ink composition described above, and substantially leaves the resin, the colorant, and the polyether-modified organosiloxane contained in the ink composition on the surface. It also relates to a recorded image formed on a recording medium that substantially absorbs the liquid component of the object.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The ink composition used in the present invention comprises an ethylenically unsaturated carboxylic acid monomer and another monomer copolymerizable therewith as an alcoholic hydroxyl group-containing water-soluble polymer compound or A copolymer having an acid value of 40 or less obtained by polymerization in the presence of a copolymerizable surfactant (hereinafter,
Sometimes referred to as "alkali-soluble copolymer". ),
It contains a resin whose pH is adjusted with an inorganic base (hereinafter sometimes referred to as "pH adjusting resin").

The alcoholic hydroxyl group-containing water-soluble polymer compound used in the production of the above-mentioned alkali-soluble copolymer is, for example, a water-soluble polymer compound having a molecular weight of 10
A compound containing 5 to 25 alcoholic hydroxyl groups per 1 00, for example, vinyl alcohol polymers such as polyvinyl alcohol and various modified products thereof; vinyl acetate and acrylic acid, methacrylic acid or maleic anhydride Saponification products of copolymers; cellulose derivatives such as alkyl cellulose, hydroxyalkyl cellulose and alkyl hydroxyalkyl cellulose; starch derivatives such as alkyl starch, carboxymethyl starch, and oxidized starch; gum arabic, tragacanth gum, polyalkylene glycol and the like. it can. Of these, vinyl alcohol-based polymers are preferable from the viewpoint of easy availability of industrially stable products.

The weight average molecular weight of the alcoholic hydroxyl group-containing water-soluble polymer compound is not particularly limited, but is usually 1.
000 to 500,000, preferably 2,000 to 30
It is 10,000. If the molecular weight is less than 1,000,
The dispersion stabilization effect may be reduced, and conversely 500,00
When it is greater than 0, the viscosity when polymerized in the presence of this polymer compound becomes high, and the polymerization may become difficult.

The amount of the alcoholic hydroxyl group-containing water-soluble polymer compound used for producing the alkali-soluble copolymer is usually 0.05 to 20 parts by weight, preferably 100 parts by weight of the monomer. Is 1 to 10 parts by weight.
If the amount is less than 0.05 parts by weight, the dispersion stabilizing effect will be low, so that aggregates will be generated during the polymerization, and if the amount is more than 20 parts by weight, the viscosity at the time of polymerization will be high and the polymerization may be difficult. .

In the production of the alkali-soluble copolymer, it is preferable not to use the surfactant usually used in emulsion polymerization, but when the surfactant is used in combination, the amount of the surfactant is alkali-soluble. Generally, based on 100 parts by weight of all monomers used for the synthesis of the copolymer,
It is less than 0.05 part by weight. When the amount of the surfactant is large, the water resistance of the obtained image tends to be poor.

The ethylenically unsaturated carboxylic acid monomer used for producing the alkali-soluble copolymer is not particularly limited, and examples thereof include ethylenically unsaturated monocarboxylic acid monomers such as acrylic acid and methacrylic acid; itacone. Ethylenically unsaturated polycarboxylic acid monomers such as acids, maleic acid, fumaric acid and butenetricarboxylic acid; ethylenically unsaturated polycarboxylic acids such as monobutyl fumarate, monobutyl maleate and mono-2-hydroxypropyl maleate Examples thereof include partial ester monomers of acids; polyvalent carboxylic acid anhydrides such as maleic anhydride and citraconic anhydride. These monomers can be used alone or in combination of two or more kinds. Among these ethylenically unsaturated acid monomers, ethylenically unsaturated monocarboxylic acids such as (meth) acrylic acid are preferable, and methacrylic acid is more preferable.

The amount of the ethylenically unsaturated carboxylic acid monomer used is an amount calculated so that the acid value of the alkali-soluble copolymer is 40 or less, preferably 10 to 40, more preferably 30 to 40. is there. If the oxidation of the alkali-soluble copolymer is more than 40 or less than 10 in terms of this amount, the quality of the obtained image may be poor.

Other monomers copolymerizable with the ethylenically unsaturated carboxylic acid monomer that can be used for producing the alkali-soluble copolymer are not particularly limited, and examples thereof include styrene and α-methyl. Styrene, vinyltoluene,
Aromatic vinyl monomers such as chlorostyrene; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, (meth) acrylic Acid-n-
Amyl, isoamyl (meth) acrylate, -n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, -n-octyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, Ethylenically unsaturated carboxylic acid ester monomers such as hydroxypropyl (meth) acrylate and glycidyl (meth) acrylate;
Ethylenically unsaturated nitrile monomers such as (meth) acrylonitrile; ethylenically unsaturated glycidyl ether monomers such as allyl glycidyl ether; (meth) acrylamide, N-methylol (meth) acrylamide, N-butoxymethyl (meth) Ethylenically unsaturated amide monomers such as acrylamide; 1,3-butadiene, isoprene,
Examples thereof include conjugated diene monomers such as 2,3-dimethyl-1,3-butadiene and 1,3-pentadiene; carboxylic acid vinyl esters such as vinyl acetate. These monomers can be used alone or in combination of two or more. Among them, in terms of excellent light resistance and gloss of the obtained image,
Ethylenically unsaturated carboxylic acid ester monomers are preferable, and methyl methacrylate and ethyl acrylate are more preferable.

The alkali-soluble copolymer can be obtained by polymerizing the above-mentioned monomer mixture, preferably in an aqueous medium, in the presence of an alcoholic hydroxyl group-containing water-soluble polymer compound. At this time, the alcoholic hydroxyl group-containing water-soluble polymer compound and the monomer mixture are added all at once to the reactor before the start of the polymerization, or a part is charged before the start of the polymerization and after the start of the polymerization. The remaining portion can be added in portions in portions, or the remaining portion can be added continuously. In the case of divided addition or continuous addition, the addition amount may be uniform or constant, and may be changed according to the stage of progress of polymerization.

The alcoholic hydroxyl group-containing water-soluble polymer compound and the monomer mixture can be obtained separately by mixing the alcoholic hydroxyl group-containing water-soluble polymer compound, the monomer mixture and water. It may be added in the form of a monomer dispersion. When the alcoholic hydroxyl group-containing water-soluble polymer compound and the monomer are added separately, it is desirable to start the addition of both at substantially the same time. Aggregates are likely to occur when only a large amount of the monomer mixture is added first, and conversely, when only a large amount of the alcoholic hydroxyl group-containing water-soluble polymer compound is added first, the polymerization system may thicken. Or, problems such as easy occurrence of aggregates are likely to occur. The addition of both does not have to be completed at the same time, but it is desirable that they are added almost at the same time.

Among the methods for adding the alcoholic hydroxyl group-containing water-soluble polymer compound and the monomer mixture, the alcoholic hydroxyl group-containing water-soluble polymer compound is mixed with the monomer mixture and water to disperse, and after the initiation of the polymerization. The method of adding to the reactor is preferable because the chain distribution of the ethylenically unsaturated acid monomer in the polymer chain of the alkali-soluble copolymer becomes uniform.

The alkali-soluble copolymer used in the production of the pH adjusting resin is an ethylenically unsaturated carboxylic acid monomer and another monomer copolymerizable therewith in the presence of a copolymerizable surfactant. Can be polymerized (preferably emulsion polymerization).

The copolymerizable surfactant is a surfactant having at least one polymerizable vinyl group in its molecule.
Specific examples thereof include sodium propenyl-2-ethylhexylsulfosuccinate, polyoxyethylene sulfate (meth) acrylic acid, polyoxyethylene alkylpropenyl ether sulfate ammonium salt, (meth) acrylic acid polyoxyethylene ester phosphate, and the like. Anionic polymerizable surfactants; nonionic polymerizable surfactants such as polyoxyethylene alkylbenzene ether (meth) acrylic acid esters and polyoxyethylene alkyl ether (meth) acrylic acid esters. Among these copolymerizable surfactants, polyoxyethylene alkylpropenyl ether ammonium salt is preferable because it has an excellent balance of the emulsion dispersion performance of the monomer and the copolymerizability with the monomer.

The amount of the copolymerizable surfactant is usually 0.01 to 5.0 parts by weight, preferably 100 parts by weight based on 100 parts by weight of all the monomers used in the synthesis of the alkali-soluble copolymer.
0.05-5.0 parts by weight, more preferably 0.1-3.
0 parts by weight. If it is less than 0.01 part by weight, the emulsion stability will be low, and a large amount of aggregates may be generated during the polymerization. On the other hand, if it exceeds 5.0 parts by weight, the resin composition may easily foam. In the polymerization of the alkali-soluble copolymer, it is preferable not to use the non-polymerizable surfactant together, but when the non-polymerizable surfactant is used together, the amount of the non-polymerizable surfactant is It is usually less than 0.05 parts by weight with respect to 100 parts by weight of the total amount of the simple substance used for the synthesis of the polymer. When the amount of the non-polymerizable surfactant is large, the water resistance of the obtained image tends to be poor.

The polymerization initiator that can be used for producing the alkali-soluble copolymer is not particularly limited. Specific examples thereof include inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, and hydrogen peroxide: diisopropylbenzene hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, 1 , 1,3,3-Tetramethylbutyl hydroperoxide, di-t-butyl peroxide, isobutyryl peroxide, benzoyl peroxide, and other organic peroxides: azobisisobutyronitrile, azobis-2,4- Examples thereof include azo compounds such as dimethylvaleronitrile and methyl azobisisobutyrate. These polymerization initiators can be used alone or in combination of two or more kinds. Of these, persulfates such as potassium persulfate and ammonium persulfate are preferable.

The amount of the polymerization initiator used varies depending on the kind thereof, but is preferably 5 to 5 parts by weight with respect to 100 parts by weight of the total monomer mixture used in the production of the aqueous dispersion of the alkali-soluble copolymer. , And more preferably 0.8 to 4 parts by weight.

Also, these polymerization initiators can be used as a redox polymerization initiator in combination with a reducing agent.

The reducing agent for the redox type polymerization initiator is not particularly limited, and specific examples thereof include a compound containing a metal ion in a reduced state such as ferrous sulfate and cuprous naphthenate; sodium methanesulfonate. And the like; amine compounds such as dimethylaniline; and the like.

These reducing agents can be used alone or in combination of two or more kinds. The amount of the reducing agent used varies depending on the reducing agent, but is 0.
It is preferably from 03 to 10 parts by weight.

In order to adjust the weight average molecular weight of the alkali-soluble copolymer, a chain transfer agent can be used at the time of polymerization, if necessary. Examples of chain transfer agents include mercaptans such as t-dodecyl mercaptan and n-dodecyl mercaptan; α-methylstyrene dimer; sulfides such as dimethylxanthogen disulfide and diisopropylxanthogen disulfide; 2-methyl-3
Nitrile compounds such as butynenitrile and 3-pentenenitrile; thioglycolic acid esters such as methyl thioglycolate, propyl thioglycolate and octyl thioglycolate; methyl β-mercaptopropionate,
β-mercaptopropionate such as octyl β-mercaptopropionate; and the like, and these can be used alone or in combination of two or more. Among these chain transfer agents, thioglycolic acid ester is preferable, and octyl thioglycolic acid is more preferable.

When a chain transfer agent is used, the amount of the chain transfer agent added is the amount of the monomer 1 used in the production of the alkali-soluble copolymer.
It is usually 0.1 to 5 parts by weight, preferably 0.5 to 4 parts by weight, based on 00 parts by weight. The amount of chain transfer agent used is
If it is too small, the viscosity after neutralization may be high and handling may be difficult, and if it is too large, the molecular weight may be significantly reduced. The addition method of the chain transfer agent is not particularly limited, and the whole amount may be added all at once, or may be added to the polymerization system in small portions intermittently or continuously.

The polymerization temperature at the time of producing the alkali-soluble copolymer is usually 0 to 100 ° C., preferably 30 to 90.
℃. The polymerization addition rate is usually 90% by weight or more, preferably 95% by weight or more.

The degree of neutralization in the neutralized product of the alkali-soluble copolymer used in the present invention (the molar equivalent of the inorganic base to the molar equivalent of the ethylenically unsaturated carboxylic acid monomer) is not particularly limited, but the neutralization The degree is usually 70% or more, preferably 95% or more.

The inorganic base used to neutralize the alkali-soluble copolymer is not particularly limited, but examples thereof include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; calcium hydroxide, Examples thereof include hydroxides of alkaline earth metals such as magnesium hydroxide, and these can be used alone or in combination of two or more kinds. Of these inorganic bases, sodium hydroxide is preferred. Ammonia may be used as the inorganic base, but the stability of the ink over time (for example, p
(Lowering of H) and ejection stability may decrease.

As the alkali-soluble copolymer used in the present invention, among the above-mentioned ones, those obtained by polymerization in the presence of a water-soluble polymer compound having an alcoholic hydroxyl group can be used when the resin composition is stored for a long period of time. In addition, it is preferable because the viscosity does not easily change and the dot reproducibility is excellent.

The weight average molecular weight of the pH adjusting resin used in the present invention is not particularly limited, but if it is too large (for example, more than 50,000), the viscosity of the aqueous resin solution becomes high, and its handling is difficult. Can be difficult. On the other hand, too low (eg less than 8,000)
And the abrasion resistance may decrease. The weight average molecular weight of the resin is, for example, preferably 8,000 or more, more preferably 9,000 to 100,000, and further preferably 10,
It is 000 to 50,000.

The glass transition temperature of the pH adjusting resin used in the present invention can be arbitrarily set, but is preferably 5 to 50.
C., more preferably 20 to 40.degree. When the glass transition temperature of the resin is within this range, an image excellent in bending resistance and blocking resistance can be obtained. In addition, even if the glass transition temperature of the pH adjusting resin used in the present invention becomes somewhat high, the film forming temperature of the ink composition of the present invention is generally kept low.

In the ink composition of the present invention, the pH adjusting resin is usually used in the state of an aqueous solution. The solid content concentration in this case is usually 1 to 40% by weight, preferably 20.
~ 30% by weight. This aqueous solution may contain a water-soluble organic solvent described later.

The pH adjusting resin used in the present invention preferably has a pH of 8 to 11 in an aqueous solution state, and more preferably has a pH of 9 to 10. If the pH is less than 8, problems may occur in ejection stability, and if it exceeds 11, problems may occur in dispersion stability.

The amount of the alkali-soluble copolymer used in the pH adjusting resin used in the present invention is preferably 2 to 200 parts by weight, more preferably 5 to 150 parts by weight, particularly preferably 5 to 150 parts by weight, based on 100 parts by weight of the colorant. Preferably 10-100
Parts by weight.

The pH adjusting resin used in the present invention can be used in the form of water-soluble resin, emulsion, polymer fine particles and the like.

The colorant used in the present invention is not particularly limited, but is, for example, a water-soluble dye or a water-insoluble pigment. Water-insoluble pigments are preferable in terms of excellent image density, light resistance, and water resistance.

As the colorant used in the present invention, any water-soluble dye used in conventional inks can be used as long as it does not cause a change in color tone or the formation of precipitates by adding other ink components. can do.

In the present invention, as the pigment that can be used with the pH adjusting resin, an inorganic pigment or an organic pigment can be used without particular limitation. As the inorganic pigment, in addition to titanium oxide and iron oxide, carbon black produced by a known method such as a contact method, a furnest method or a thermal method can be used. The organic pigments include azo dyes (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, etc.), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, Dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinofuranone pigments), dye chelates (for example, basic dye chelates, acid dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, etc. can be used.

Particularly, carbon black used as black ink is No. 1 manufactured by Mitsubishi Chemical Corporation. 2300,
No. 900, HCF88, No. 33, No. 40,
No. 45, No. 52, MA7, MA8, MA10
0, No. 2200B is Rave made by Colombia
n5750, Raven5250, Raven500
0, Raven3500, Raven1255, Rav
en700 etc. is Regal400 made by Cabot
R, Regal330R, Regal660R, Mog
ul L, Monarch700, Monarch80
0, Monarch 880, Monarch 900, M
onarch1000, Monarch1100, Mo
narch1300, Monarch1400, etc. are Color Black FW1 and Colo manufactured by Degussa.
r Black FW2, ColorBlack FW
2V, Color Black FW18, Color
Black FW200, Color Black
S150, Color Black S160, Col
or Black S170, Printex 35,
Printex U, Printex V, Print
ex 140U, Special Black 6, S
special Black 5, SpecialBla
ck 4A, Special Black 4 and the like can be used, but the present invention is not limited to these.

As the pigment used in the yellow ink, C.I. I. Pigment Yellow 1, C.I.
I. Pigment Yellow 2, C.I. I. Pi
gment Yellow 3, C.I. I. Pigmen
t Yellow 12, C.I. I. Pigment Y
ellow 13, C.I. I. Pigment Yell
ow 14C, C.I. I. Pigment Yellow
16, C.I. I. Pigment Yellow 1
7, C.I. I. Pigment Yellow 73C.
I. Pigment Yellow 74, C.I. I. P
igment Yellow 75, C.I. I. Pigm
ent Yellow 83, C.I. I. Pigment
Yellow 93, C.I. I. Pigment Ye
low 95, C.I. I. Pigment Yellow
w 97, C.I. I. Pigment Yellow 9
8, C.I. I. Pigment Yellow 110,
C. I. Pigment Yellow 114, C.I.
I. Pigment Yellow 128, C.I. I.
Pigment Yellow 129, C.I. I. Pi
gment Yellow 151, C.I. I. Pigm
ent Yellow 154 and the like. Further, as a pigment used for magenta ink, C.I. I. Pi
gment Red 5, C.I. I. Pigment R
ed 7, C.I. I. Pigment Red 12,
C. I. Pigment Red 48 (Ca), C.I.
I. Pigment Red 48 (Mn), C.I. I.
Pigment Red 57 (Ca), C.I. I. Pi
gment Red 57: 1, C.I. I. Pigmen
tRed 112, C.I. I. Pigment Red
122, C.I. I. Pigment Red 123,
C. I. Pigment Red 168, C.I. I. P
igment Red 184, C.I. I. Pigmen
t Red 202, C.I. I. Pigment Red
209 and the like.

The pigment used in the cyan ink is
C. I. Pigment Blue 1, C.I. I. Pig
ment Blue 2, C.I. I. Pigment B
lue 3, C.I. I. Pigment Blue 1
5: 3, C.I. I. Pigment Blue 15: 3
4, C.I. I. Pigment Blue 16, C.I.
I. Pigment Blue 22, C.I. I. Pig
ment Blue 60, C.I. I. Vat Blue
4, C.I. I. Vat Blue 60 etc. are mentioned. However, it is not limited to these.

The particle size of the pigment is preferably 10 μm or less,
The thickness is more preferably 1 μm or less, further preferably 0.1 μm or less.

In the present invention, together with the pH adjusting resin,
According to a preferred embodiment of the pigment that can be used, these pigments are preferably added to the ink as a pigment dispersion obtained by dispersing the pigment in an aqueous medium.
The dispersant used to prepare the pigment dispersion,
A dispersant generally used for preparing a pigment dispersion, for example, a polymer dispersant or a surfactant can be used. As the surfactant used as a dispersant,
Examples include various anionic surfactants, nonionic surfactants, cationic surfactants and amphoteric surfactants described below.

Preferred examples of the polymer dispersant include natural polymers, and specific examples thereof include proteins such as glue, gelatin, casein and albumin, natural gums such as gum arabic and tragacanth, and savonin. Glycosides, alginic acid and propylene glycol alginate, alginate triethanolamine, alginate derivatives such as ammonium alginate,
Examples thereof include cellulose derivatives such as methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose and ethyl hydroxycellulose.

Further, preferred examples of the polymer dispersant include synthetic polymers such as polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer and acetic acid. Acrylic resin such as vinyl-acrylic acid ester copolymer, acrylic acid-acrylic acid ester copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid ester copolymer Styrene-acrylic resins such as polymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride Acid copolymer, vinylnaphthalene-acrylic Acid copolymer, vinylnaphthalene-
Maleic acid copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinyl ethylene copolymer, vinyl acetate-maleic acid ester copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-acrylic acid copolymer Examples thereof include vinyl acetate-based copolymers such as polymers and salts thereof.

Of these, a copolymer of a monomer having a hydrophobic group and a monomer having a hydrophilic group, and a polymer having a monomer having both a hydrophobic group and a hydrophilic group in the molecular structure are preferable. .

Further, in the present invention, according to another preferable embodiment of the pigment that can be used together with the pH adjusting resin, it is preferable to use carbon black whose surface is oxidized. In this embodiment, the above dispersant may not be used. The oxidation treatment can be performed by a known method. By the oxidation treatment, hydrophilic groups such as carbonyl group, carboxyl group, hydroxyl group and sulfone group can be introduced on the surface of carbon black. The above-mentioned carbon black is used.

In the ink composition of the present invention, the content of the pH adjusting resin and the colorant is 0.5 to 50 in terms of the total amount of the pH adjusting resin and the colorant with respect to the total weight of the ink composition.
About 10% by weight is preferable, and more preferably 2 to 30% by weight.
It is a degree. In the ink composition of the present invention, p
The content ratio of the H adjustment resin and the colorant (water-soluble pH adjustment resin / colorant) is not particularly limited, but is preferably 0.0
It is 5 to 1.0, and more preferably 0.1 to 0.5.

The ink composition according to the present invention comprises the compound of the above formula (1).

In the formula (1), R ^{1 to} R ⁹ independently represent a C _1-6 alkyl group or an aryl group, preferably a methyl group. j and k represent an independent integer of 1 or more, m and n represent an integer of 0 or more, provided that j + k represents an integer of 0 or more.

In order to obtain sufficient abrasion resistance and scratch resistance, j + k is preferably 11 to 300.
1-100 are more preferable, and 11-50 are especially preferable.

The amount of the compound of formula (1) added may be appropriately determined, but is preferably about 0.05 to 5% by weight, more preferably about 0.1 to 3.0% by weight.

The compound of formula (1) is commercially available and can be used. For example, Big Chemie
From Japan Co., Ltd., silicon additive BYK-30
6, BYK-307, BYK-333, BYK-341
Is available.

The ink composition of the present invention contains water as a solvent and may further contain a water-soluble organic solvent.

Examples of water-soluble organic solvents include methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, sec-butanol, tert-butanol, iso-butanol, n-butanol.
Pentanol, ethylene glycol, propylene glycol, diethylene glycol, pentamethylene glycol, trimethylene glycol, 2-butyne-1,4-diol, 2-ethyl-1,3-hexanediol, 2-
Methyl-2,4-pentanediol, N-methyl-2-
Pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 2-pyrrolidone, glycerin, tripropylene glycol monomethyl ether, dipropylene glycol monoethyl glycol, dipropylene glycol monomethyl ether, dipropylene glycol, triethylene glycol monomethyl ether, tetra Examples thereof include ethylene glycol, triethylene glycol, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether and diethylene glycol monomethyl ether.

In the ink composition of the present invention, the content when a water-soluble organic solvent is used is preferably about 10 to 40% by weight, more preferably 10 to 20% by weight based on the total weight of the ink composition. % By weight.

The ink composition of the preferred embodiment of the present invention comprises
Further, a surfactant can be contained. The surfactant used in the present invention is one or more surfactants selected from the group consisting of anionic surfactants, nonionic surfactants, and amphoteric surfactants.

Examples of surfactants include anionic surfactants (eg sodium dodecylbenzene sulfonate,
Sodium lauryl sulfate, ammonium salts of polyoxyethylene alkyl ether sulfate, etc., nonionic surfactants (eg polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, poly Oxyethylene alkylamine, polyoxyethylene alkylamide, etc.) and acetylene glycol. These may be used alone or in combination of two or more.

Further, the ink composition according to the preferred embodiment of the present invention contains a tertiary amine as a pH adjusting agent.

The tertiary amine that can be added to the ink composition according to the present invention includes trimethylamine, triethylamine, triethanolamine, dimethylethanolamine, diethylethanolamine, triisopropanolamine, butyldiethanolamine and the like.
These may be used alone or in combination. The amount of these tertiary amines added to the ink composition of the present invention is
It is 0.1 to 10% by weight, and more preferably 0.5 to 5% by weight.

Further, the ink composition according to the present invention may contain a penetration enhancer, a sugar, and / or an alginic acid derivative.

Examples of the penetration enhancer include alkyl ether derivatives of polyhydric alcohols having 3 or more carbon atoms, such as diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, and the like. And one or more of these can be used. Examples of sugars include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides) and polysaccharides, preferably glucose, mannose, fructose, ribose, xylose, arabinose, galactose, aldonic acid. , Glucitol, (sorbit), maltose, cellobiose, lactose, sucrose, trehalose, maltotriose, and the like. Here, the term "polysaccharide" means a sugar in a broad sense, and is meant to include substances widely existing in nature such as alginic acid, α-cyclodextrin, and cellulose. In addition, examples of derivatives of these sugars include reducing sugars [(for example, sugar alcohols (general formula: HOCH ₂ (CHOH) _n CH ₂ OH (where n represents an integer of 2 to 5)] ), Oxidized sugars (eg, aldonic acid, uronic acid, etc.), amino acids, thiosugars, etc. Sugar alcohols are particularly preferable, and specific examples thereof include maltitol, sorbitol and the like. The amount of sugar added is 0.1
The amount is preferably about 40% by weight, more preferably about 1 to 30% by weight. Commercially available products can be used as these saccharides, and specific examples thereof include HS-300 and HS-.
500 (trade name of Hayashibara Shoji Co., Ltd.) can be mentioned. Preferable examples of the alginic acid derivative include alkali metal alginate salts (for example, sodium salt and potassium salt), organic alginate salts (for example, triethanolamine salt), ammonium alginate salt and the like. The amount of the alginic acid derivative added to the ink composition is preferably about 0.01 to 1% by weight, more preferably 0.1.
It is about 05 to 0.5% by weight.

Although the reason why a good image is obtained by adding the alginic acid derivative is not clear, the polyvalent metal salt present after the reaction reacts with the alginic acid derivative in the ink composition to change the dispersion state of the colorant. It is considered that this is because the fixing of the colorant to the recording medium is promoted.

In addition to the ink composition according to the present invention,
If necessary, a preservative, a fungicide, and / or a phosphoric acid-based antioxidant can be added.

The ink composition of the present invention can be prepared by a conventional method, for example, by dispersing and mixing the above-mentioned components by an appropriate method. Preferably, first, a pigment, a polymer dispersant, and ion-exchanged water are dispersed in a suitable disperser (for example, ball mill, sand mill, attritor, roll mill, agitator mill, Henschel mixer, colloid mill, ultrasonic homogenizer, jet mill, ong mill). Etc.) to prepare a uniform pigment dispersion. Next, the pH adjusting resin aqueous solution, polyether modified organosiloxane, ion-exchanged water, water-soluble organic solvent, preservative, and / or fungicide are sufficiently stirred at room temperature to prepare an ink solvent. While the ink solvent is being stirred by a suitable disperser, the pigment dispersion is gradually added and sufficiently stirred. After sufficiently stirring, the target ink composition can be obtained by performing filtration in order to remove coarse particles and foreign matters that cause clogging.

The ink composition of the present invention can be used in any printing method, and can be suitably used as, for example, a water-based gravure ink, a water-based flexo ink, or particularly a water-based ink for inkjet recording. It can also be used as an aqueous paint.

In the ink composition of the present invention, as a recording medium, the pH adjusting resin, the colorant (particularly pigment) and the polyether-modified organosiloxane contained in the ink composition are substantially left on the surface. It is particularly preferably used for a recording medium that substantially absorbs the liquid component of the ink composition. In such a recording medium, for example, the average pore diameter on the surface is smaller than the average particle diameter of the pigment. A preferred recording medium is a recording medium including an ink receiving layer having an average pore size smaller than the average particle size of the pigment.

As a preferable recording medium, a recording medium provided with an ink receiving layer containing a porous pigment on a substrate can be used. The ink receiving layer can be the uppermost layer of the recording medium, or it can be an intermediate layer having a gloss layer thereon, for example. As such a recording medium, a so-called absorptive (also referred to as void type) recording medium containing a porous pigment and a binder resin in the ink receiving layer, and casein, modified polyvinyl alcohol ( A so-called swelling type recording medium further containing a resin such as PVA), gelatin, or modified urethane is known, and the ink composition of the present invention can be used for any recording medium.

Examples of the porous pigment contained in the ink receiving layer of the absorptive recording medium include silica-based pigments such as those obtained by precipitation method, gel-type method or vapor-phase method, alumina hydrates such as pseudo-boehmite, silica / Alumina hybrid sol, smectite clay, calcium carbonate, calcium sulfate, barium sulfate, titanium dioxide, kaolin, clay, talc, magnesium silicate, calcium silicate and the like can be mentioned, and one or more of these can be used. it can.

The binder resin contained in the ink receiving layer of the absorptive recording medium is not particularly limited as long as it has a binding ability and can enhance the strength of the ink receiving layer. , Polyvinyl alcohol, silanol modified polyvinyl alcohol, vinyl acetate, starch, cellulose derivatives such as carboxymethyl cellulose, casein, gelatin, conjugated diene copolymer latex such as styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, etc. Examples thereof include vinyl copolymer latex, acrylic copolymer latex such as polymers of acrylic acid and methacrylic acid.

The ink receiving layer may be a fixing agent, a fluorescent whitening agent, a water-proofing agent or not, whether it is an ink receiving layer of an absorption type recording medium or an ink receiving layer of a swelling type recording medium. , Antifungal agent, preservative, dispersant, surfactant, thickener,
Various additives such as a pH adjusting agent, a defoaming agent, and / or a water retention agent can be contained.

The substrate on which each of the ink receiving layers is provided includes paper (including size-treated paper); resin-coated paper obtained by coating polyethylene, polypropylene, polyester or the like on paper; baryta paper; polyethylene terephthalate, polyethylene. Or a thermoplastic resin film such as polypropylene; synthetic paper; a sheet-like material formed of synthetic fibers, and the like.

A recording medium of a particularly preferred embodiment is a recording medium having the above-mentioned base material and the above-mentioned ink receiving layer as the uppermost layer provided thereon. The base material and the ink receiving layer are also, for example, Those having the following physical properties are preferable.

The base material is preferably paper (containing wood pulp), and its weight is preferably 100.
To 350 g / m ² , more preferably 180 to 260 g / m ² .
m ² . The thickness is preferably 100 to 400.
μm, and more preferably 180 to 260 μm. The ink receiving layer contains wet method silica gel in an amount of 50 to 60 wt% as the porous pigment based on the total weight of the ink receiving layer in terms of solid content, and polyvinyl alcohol as the binder resin in an amount of 30 to 60% by weight. The content of 40% by weight is preferable from the viewpoints of ink absorbability, printing fastness and the like. The coating amount of the ink receiving layer is
From the viewpoint of ink absorbability, it is preferably 5 to 50 g / m ² in terms of solid content. The thickness of the ink receiving layer itself is preferably 10 to 40 μm, more preferably 20 to 30 μm.

The recording medium on which the ink composition of the present invention is printed preferably has an average pore diameter of 50 nm or less on the surface (particularly, the ink receiving layer) of the recording medium, and 30 nm.
The following is more preferable. Average pore size is 300nm
If it exceeds, the pigment may penetrate into the ink receiving layer and the color developability may deteriorate.

[0090]

The present invention will be described in more detail with reference to the following examples, which are not intended to limit the scope of the present invention. In the examples, "%" and "parts" are based on weight unless otherwise specified. Moreover, the acid value of the copolymer obtained in the following preparation examples was measured according to JIS K 0070.

Preparation Example 1 <Preparation of pH adjusting resin> 60 parts of ethyl methacrylate, 36 parts of methyl methacrylate, 4 parts of methacrylic acid, 3 parts of octyl thioglycolate as a molecular weight adjusting agent, 1 part of polyvinyl alcohol and ion exchange. 280 parts of water was stirred and mixed to prepare a dispersion of the monomer mixture.

In another reactor equipped with a stirrer, 1 ion-exchanged water was added.
30 parts and 2 parts of potassium persulfate were charged, the temperature was raised to 80 ° C., and the dispersion of the monomer mixture was continuously added over 4 hours to polymerize. After the continuous addition, at 80 ℃,
The reaction was carried out for 30 minutes. The polymerization conversion rate was 99% or more.

Then, 10% aqueous sodium hydroxide solution in an amount corresponding to the charged methacrylic acid and sodium hydroxide in an equimolar amount was added to the reactor and further heat-treated at 80 ° C. for 1 hour, and then an appropriate amount of ions was added. Exchanged water was added to obtain a pH-adjusted resin solution A having a solid content concentration of 15%. The acid value of this pH adjusting resin solution A was 30.

Preparation Example 2 <Preparation of pH adjusting resin> 56 parts of ethyl acrylate, 36 parts of methyl methacrylate, 8 parts of methacrylic acid, 3 parts of octyl thioglycolate as a molecular weight adjusting agent, 2.5 parts of sodium lauryl sulfate. And 80 parts of ion-exchanged water were mixed by stirring to prepare a dispersion of the monomer mixture.

In another reactor equipped with a stirrer, 90 parts of ion-exchanged water in which 0.05 part of ethylenediaminetetraacetic acid was dissolved was heated to 80 ° C., and a 40% aqueous solution of potassium persulfate 40
After adding 1 part, the dispersion of the monomer mixture was continuously added and polymerized for 2 hours. 80 ° C after continuous addition
The reaction was carried out for 30 minutes. The polymerization conversion rate was 99% or more.

Then, 2 parts of 28% aqueous ammonia solution and 5% aqueous 5% sodium persulfate solution in an amount corresponding to the charged methacrylic acid and an equimolar amount of ammonia were added to the reactor and further treated at 80 ° C. for 1 hour. After that, an appropriate amount of ion-exchanged water was added to obtain a pH-adjusted resin solution B having a solid content of 25%.
The acid value of this pH adjusting resin solution B was 50.

<Preparation of Ink> A pigment, a dispersant and water are mixed and dispersed in a sand mill (manufactured by Yasukawa Seisakusho) with glass beads [diameter 1.7 mm, 1.5 times amount (weight) of the mixture] for 2 hours. After that, remove the glass beads,
A pigment dispersion was prepared.

Then, the solvent excluding the pigment and the dispersant and the polyether-modified organosiloxane are mixed to prepare an ink solvent, and the pigment dispersion and the p prepared in the above Preparation Example are mixed.
While the H-adjusting resin solution A or B was being stirred, the above ink solvent was gradually added dropwise and the sales were expanded at room temperature for 20 minutes. 5 μm
To obtain an ink jet recording ink.

[0099] (Example 1)   <Black pigment ink> Carbon black MA7 (Mitsubishi Chemical Corporation) 3 weight % Styrene-acrylic acid copolymer (dispersant) 1% by weight pH adjusting resin A 2% by weight BYK307 3% by weight Glycerin 10% by weight Deionized water remaining

[0100] (Comparative Example 1)   <Black pigment ink> C. I. Pigment Black 1 1 weight % Styrene-acrylic acid copolymer (dispersant) 1% by weight pH adjusting resin B 2% by weight BYK307 3% by weight Glycerin 10% by weight Deionized water remaining

[0101] (Comparative example 2)   <Black pigment ink> Carbon black MA7 (Mitsubishi Chemical Corporation) Single amount% Styrene-acrylic acid copolymer (dispersant) 1% by weight pH adjusting resin A 2% by weight Glycerin 10% by weight Deionized water remaining

[0102] (Example 2)   <Color ink set> (1) Cyan ink C. I. Pigment Blue 15:32 2% by weight Styrene-acrylic acid copolymer (dispersant) 1% by weight pH adjusting resin A 2% by weight BYK307 3% by weight Triethylene glycol monobutyl ether 10% by weight Diethylene glycol 10% by weight Deionized water remaining (2) Magenta ink C. I. Pigment Red 122 3% by weight Styrene-acrylic acid copolymer (dispersant) 1% by weight pH adjusting resin A 2% by weight BYK307 3% by weight Triethylene glycol monobutyl ether 10% by weight Glycerin 5% by weight Diethylene glycol 5% by weight Deionized water remaining (3) Yellow ink C. I. Pigment Yellow 74 3.5 Weight % Styrene-acrylic acid copolymer (dispersant) 1% by weight pH adjusting resin A 2% by weight BYK307 3% by weight Triethylene glycol monobutyl ether 10% by weight Glycerin 8% by weight Deionized water remaining

<Print Evaluation> Print evaluation was carried out using each of the ink compositions produced in the above Examples and Comparative Examples. Inkjet printer [PM-920C
(Seiko Epson Corp.), PM photo paper [Inkjet dedicated paper: Seiko Epson Corp.]
Was printed on. (1) Rubbing resistance evaluation 1 (evaluation by rubbing with a finger) After 3 minutes from printing, the surface of the printed recording medium was rubbed with a finger, and the rubbing resistance was visually evaluated by peeling off the coloring material. The evaluation criteria are as follows. A: There is no peeling of the coloring material. B: There is slight peeling of the coloring material (less than 20% of the entire coloring material). C: There is peeling of the coloring material (20% or more and less than 80% of the entire coloring material). D: Most of the coloring material is peeled off (80% or more of the entire coloring material is peeled off). (2) Rubbing resistance evaluation 2 (evaluation according to JIS K5701) At 48 hours after printing, a rubbing resistance was evaluated according to JISK5701, using a Southerland Lab tester. The evaluation criteria are as follows. A: There is no peeling of the coloring material. B: There is slight peeling of the coloring material (less than 20% of the entire coloring material). C: There is peeling of the coloring material (20% or more and less than 80% of the entire coloring material). D: Most of the coloring material is peeled off (80% or more of the entire coloring material is peeled off). (3) Scratch resistance evaluation After 3 minutes from printing, the scratch resistance was visually judged by rubbing the print medium with a nail and scratching the surface of the recording medium. The evaluation criteria are as follows. A: There is no scratch on the surface of the recording medium. B: The surface of the recording medium is slightly scratched. C: The surface of the recording medium is scratched, but the coloring material is not peeled off. D: The surface of the recording medium is scratched and the coloring material is peeled off. (4) Results (a) The results for the ink compositions prepared in Example 1 and Comparative Examples 1 and 2 are shown in the table below.

[0104]

[Table 1]

As is clear from the evaluation results shown in Table 1,
The aqueous pigment ink composition containing the pH adjusting resin and the polyether-modified organosiloxane according to the present invention results in improved scratch resistance and scratch resistance. (B) The color ink composition produced in Example 2 was evaluated for printing in the same manner as described above.
The same result as in the section of Example 1 of was obtained. That is, the scratch resistances 1 and 2 were both evaluated as "A", and the scratch resistance was also evaluated as "A".

In Example 2, instead of using the pH adjusting resin solution A (2% by weight),
An ink composition prepared in the same manner as in Example 2 except that the adjusted resin solution B (2% by weight) was used was subjected to the same printing evaluation as above, and it was found that the abrasion resistance 1 and 2 were both Was also evaluated as "C", and scratch resistance was also evaluated as "C". Further, the same printing evaluation as above was performed on the ink composition prepared in the same manner as in Example 2 except that the polyether-modified organosiloxane was not used in Example 2 above.
Scratch resistance 1 was evaluated as "B", scratch resistance 2 was evaluated as "D", and scratch resistance was evaluated as "A".

[0107]

According to the ink composition of the present invention, it is possible to obtain a recorded matter having excellent abrasion resistance and scratch resistance.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C056 EA13 FC02                 2H086 BA53 BA55 BA59 BA60 BA62                 4J039 AD06 AD09 AD13 AD14 AD20                       AD23 AE07 AE11 AF07 BA14                       BA29 BA30 BE01 BE22 BE30                       CA06 EA36 EA48 GA24

Claims (13)

[Claims] 1. An ethylenically unsaturated carboxylic acid monomer and another monomer copolymerizable therewith are polymerized in the presence of an alcoholic hydroxyl group-containing water-soluble polymer compound or a copolymerizable surfactant. The resulting copolymer having an acid value of 40 or less, containing a resin whose pH is adjusted with an inorganic base, water, a colorant, and a polyether-modified organosiloxane represented by the following formula (1): A featured ink composition. [Chemical 1] (1) (In the above formula, R ^{1 to} R ⁹ independently represent a C _1-6 alkyl group or an aryl group, j and k each independently represent an integer of 0 or more, and EO represents an ethyleneoxy group. Represents PO
Represents a propyleneoxy group, m and n represent an integer of 0 or more, provided that m + n represents an integer of 1 or more, and EO and PO are in random blocks regardless of their order in []. May be ) 2. The compound of formula (1) has a compound of j + k = 11 to 3
The ink composition according to claim 1, wherein the ink composition is 00. 3. The ink composition according to claim ¹ , wherein R ^{1 to} R ^{9 in} the compound of formula (1) all represent a methyl group. 4. The ink composition according to claim 1, which comprises 0.05 to 5.0% by weight of the compound of formula (1). 5. The method according to claim 1, wherein the colorant is a pigment.
The ink composition according to any one of 4 above. 6. The ink composition according to claim 1, wherein the inorganic base used for preparing the resin is an alkali metal hydroxide or an alkaline earth metal hydroxide. 7. The ink composition according to claim 1, wherein the alcoholic hydroxyl group-containing water-soluble polymer compound used in the preparation of the resin is a vinyl alcohol polymer. 8. The ink composition according to any one of claims 1 to 7, wherein the ethylenically unsaturated carboxylic acid monomer used for preparing the resin is acrylic acid or methacrylic acid. 9. The method according to claim 1, wherein the monomer copolymerizable with the ethylenically unsaturated carboxylic acid monomer used for preparing the resin is an ethylenically unsaturated carboxylic acid ester monomer. The ink composition according to any one of items. 10. The ink composition according to claim 1, wherein the resin has a pH of 8 to 11. 11. The ink composition according to claim 1, which is an ink composition for inkjet recording. 12. The ink composition according to claim 1, wherein the resin, the colorant, and the polyether-modified organosiloxane contained in the ink composition substantially remain on the surface. However, a method of recording on a recording medium that substantially absorbs the liquid component of the ink composition. 13. The ink composition according to claim 1, wherein the resin, the colorant, and the polyether-modified organosiloxane contained in the ink composition substantially remain on the surface. Recorded image formed on a recording medium that substantially absorbs the liquid component of the ink composition.