JP2002120452A - Composition for ink jet recording material, and body to be recorded or recording sheet using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for an ink jet recording material by which an inexpensive ink accepting layer, and excellent in glossiness, ink absorbency, drying property, and water resistance as well can be obtained, and in addition, a body to be recorded or a recording sheet using the same. SOLUTION: This composition for the ink jet recording material comprises a dispersion liquid containing an inorganic particle, a binder resin and a water- based solvent. In such a composition for the ink jet recording material, a specified resin is adopted as the binder resin. In addition, the average particle diameter of the inorganic particle is made a specified size or lower by applying a pulverizing/dispersing treatment to the dispersion liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for an ink jet recording material and a recording medium or a recording sheet, and more particularly to a low-cost, excellent mechanical stability, clear, glossy and ink-absorbing material. The present invention relates to a composition for an ink jet recording material capable of obtaining an ink receiving layer having excellent drying properties and water resistance, and a recording medium or a recording sheet using the same.

[0002]

2. Description of the Related Art In recent years, ink jet recording systems are inexpensive, easy to produce full color, have low noise, and are excellent in printing quality. Therefore, applications to various facsimile machines and printers are rapidly spreading. is there. In the inkjet recording method, water-based ink is mainly used from the viewpoint of safety and recording suitability, and recording is performed by flying ink dots from a nozzle toward a recording sheet. Therefore, it is required that the recording sheet absorb the ink promptly. Further, by increasing the number of colors of the ink and reducing the particle size of the ink dots, it has become possible to obtain recording comparable to silver halide photographic images, and the recording speed has been increased. As described above, in the ink jet recording method, the recording apparatus and the recording method have been improved, and accordingly, the ink jet recording material has been required to have high properties.

Various recording sheets have conventionally been used as ink jet recording materials. For example, plain paper, coated paper (art paper, coated paper, cast-coated paper, etc.), and in addition to these papers, transparent or opaque plastic films, synthetic paper, or RC coated on both sides with plastic on both sides A recording sheet in which an ink receiving layer is provided on a support such as paper is used.

The ink receiving layer is formed mainly of a water-soluble or hydrophilic resin such as polyvinyl alcohol, which is a so-called swelling type ink receiving layer, and the so-called void type ink receiving layer formed mainly of a fine particle component such as silica. It can be broadly divided into layers.

[0005] The swelling type ink receiving layer is comparable to a silver salt photographic image having extremely high gloss and color density after the ink solvent composed of water and a high boiling point organic solvent (glycerin, ethylene glycol or the like) is completely evaporated. It has the advantage that an image can be obtained, but the ink absorption rate (drying rate) is lower than that of the void type ink receiving layer, and in some cases,
Due to the high boiling point organic solvent in the ink solvent, the ink receiving layer remains wet for several hours to several days after printing,
There are disadvantages that the images are sticky and the images cannot be superimposed. In addition, there is a problem that an image defect such as beading occurs due to insufficient ink absorbency in a portion where the amount of printing ink is large, and it is difficult to achieve both ink absorbency and water resistance. In particular, as the speed of the printer is increased, the use of photo inks, and the image quality is increased, such as high-resolution printing of 1000 dpi or more, the problem of a low ink absorption speed (drying speed) has become a problem.

[0006] Therefore, as the ink receiving layer, a void type ink receiving layer having an excellent ink absorption rate (drying rate) is becoming mainstream. The void-type ink-receiving layer has high ink absorbency because the ink is absorbed in the voids of the inorganic fine particles, so that image defects such as beading are unlikely to occur,
Since water-insoluble inorganic fine particles are the main component, it has high water resistance. In addition, if the thickness of the ink receiving layer is set so as to ensure a sufficient ink absorption capacity, the surface of the ink receiving layer becomes apparently dry immediately after printing, and the image touches or overlaps the image. Drying rate. Although the gap type ink receiving layer has many advantages as described above, it has a problem that the glossiness of the ink receiving layer is low because inorganic fine particles are used to enhance ink absorption.

The above-mentioned void type ink receiving layer is disclosed in, for example, JP-A-60-219084, JP-A-63-170074, JP-A-2-43083, and JP-A-4-93284. JP-A-7-137
No. 431, JP-A-8-197832 and the like disclose those using various inorganic particles. here,
Regarding the coating liquid for forming the void-type ink receiving layer on the support, the inorganic fine particles used to increase the gloss of the ink receiving layer can be reduced in particle size, or the binder can close the voids and absorb ink. Studies have been made to reduce the binder content or to use a low swelling binder to improve the properties of the ink receiving layer so that the ink receiving layer is not damaged.

However, when the binder content is reduced, the coating film forming the ink receiving layer becomes brittle, and the inorganic fine particles fall off and cracks occur, so that the surface of the receiving layer having high flatness cannot be formed. In addition, there is a problem that high glossiness and a clear printed image cannot be obtained, and a problem in production that inorganic fine particle components settle and separate during production due to poor mechanical stability of the coating solution.

By the way, colloidal silica made of sodium silicate is typical as a dispersion of inorganic fine particles in an aqueous solvent. Colloidal silica is synthesized in the liquid phase and is produced as it is without drying.It has extremely high mechanical stability, and also has a small particle size. Used when required. However, colloidal silica is problematic in that its productivity is low and expensive due to its manufacturing method, and the usable range is limited in terms of economy. Further, since the void volume is small, it is necessary to increase the thickness of the ink receiving layer in order to obtain sufficient ink absorbency.

On the other hand, as the inorganic fine particles, which have a large void volume, have a sufficient ink absorbency and are also economical, dry silica and sodium silicate produced by a gas phase method using silicon tetrachloride as a raw material. And wet silica such as precipitated silica and gel silica produced by neutralizing the silica. However, since these silica particles are obtained as an aggregated powder, it is difficult to stably disperse them in a solvent, and silica particles having an average particle size of 0.5 μm or less are stably dispersed, and the A dispersion for the ink receiving layer that can provide gloss is not obtained.

For this reason, the composition for an ink jet recording material which solves the above-mentioned problems of the prior art, is inexpensive, has excellent mechanical stability, and provides an ink receiving layer having excellent ink absorption and gloss. Further, development of a recording medium or a recording sheet using the same has been strongly demanded.

[0012]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, it is an object of the present invention to provide an inexpensive, excellent mechanical stability, gloss, ink absorption, drying property and water resistance. An object of the present invention is to provide a composition for an ink jet recording material from which an excellent ink receiving layer can be obtained, and a recording medium or a recording sheet using the composition.

[0013]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, have found that a composition for an ink jet recording material comprising a dispersion liquid containing inorganic fine particles, a binder resin and an aqueous solvent. The present inventors have found that the above object can be achieved when a specific resin is employed as a binder resin, and further, when the average particle diameter of the inorganic fine particles is reduced to a specific size or less by subjecting the dispersion to pulverization and dispersion treatment, the present invention Was completed.

According to the first aspect of the present invention, there is provided a composition for an ink jet recording material comprising a dispersion containing inorganic fine particles (A), a binder resin (B) and an aqueous solvent (C). (B) is a hydrolyzable silyl group-containing acrylic copolymer, and the dispersion is subjected to pulverization and dispersion treatment so that the average particle size of the inorganic fine particles (A) is 0.5 μm or less. A composition for an ink jet recording material is provided.

According to a second aspect of the present invention, the first aspect
In the invention, the inorganic fine particles (A) have an average particle size of 1 to 5
There is provided a composition for an inkjet recording material, which is a silica having a thickness of 0 μm.

According to a third aspect of the present invention, the first aspect is provided.
In the invention, the binder resin (B) is composed of 0.5 to 15% by weight of a polymerizable unsaturated monomer having a hydrolyzable silyl group and 99.5 to 85% by weight of another polymerizable unsaturated monomer. And a water-soluble solvent (C) is added to a resin solution obtained by solution polymerization to form an emulsion, and the polymerization solvent is removed. The present invention provides a composition for an ink jet recording material, characterized in that the composition is made into an aqueous resin composition by heating.

According to the fourth aspect of the present invention, the first aspect is provided.
In the invention of (1), the mixing ratio of the inorganic fine particles (A) and the binder resin (B) is such that (A) is 70 in terms of solid content.
(B) is 30 to 3% by weight with respect to 97% by weight of the composition for an ink jet recording material.

According to a fifth aspect of the present invention, there is provided the composition for an ink jet recording material according to the first aspect, wherein the hydrolyzable silyl group-containing acrylic copolymer is a cationic resin. Is provided.

According to a sixth aspect of the present invention, there is provided an ink-receiving layer formed of the ink-jet recording material composition of any one of the first to fifth aspects on a support. The recording medium or the recording sheet described above is provided.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

1. Inorganic fine particles (A) Examples of the inorganic fine particles (A) used in the present invention include alumina, silica, calcium carbonate, aluminum hydroxide, and calcium silicate. Preferred is silica, and particularly preferred is synthetic silica such as dry silica produced by a gas phase method using silicon tetrachloride as a raw material, wet silica such as precipitated silica or gel silica produced by neutralizing sodium silicate. It is. These inorganic fine particles are usually
It is obtained as aggregated particles having an average particle size of 1 to 50 μm.

2. Binder Resin (B) As the binder resin (B) used in the present invention, a hydrolyzable silyl group-containing acrylic copolymer is used.
The hydrolyzable silyl group-containing acrylic copolymer is obtained by copolymerizing a polymerizable unsaturated monomer (a) having a hydrolyzable silyl group described below with another polymerizable unsaturated monomer (b). It is obtained by doing. The content of the polymerizable unsaturated monomer (a) having a hydrolyzable silyl group in the acrylic copolymer is usually 0.5 to 15% by weight, preferably 1 to 12% by weight, more preferably 2% by weight. -10% by weight.

(A) Polymerizable having a hydrolyzable silyl group
Unsaturated monomer As a polymerizable unsaturated monomer having a hydrolyzable silyl group
Is, for example, vinyltrimethoxysilane, vinyltrie
Toxic silane, vinyl tributoxy silane, vinyl meth
Xydimethylsilane, vinylethoxydimethylsilane,
Vinyl isobutoxy dimethyl silane, vinyl dimethoxy
Methylsilane, vinyldiethoxymethylsilane, vinyl
Tris (β-methoxyethoxy) silane, vinyl diphe
Nylethoxysilane, vinyltriphenoxysilane, γ
-(Vinylphenylaminopropyl) trimethoxysila
, Γ- (vinylbenzylaminopropyl) trimethoxy
Sisilane, γ- (vinylphenylaminopropyl) tri
Ethoxysilane, γ- (vinylbenzylaminopropyl
Le) triethoxysilane, divinyldimethoxysilane,
Divinyldiethoxysilane, divinyldi (β-methoxy
Ethoxy) silane, vinyldiacetoxymethylsilane,
Vinyltriacetoxysilane, vinylbis (dimethylamine
Mino) methylsilane, vinylmethyldichlorosilane, bi
Nyldimethylchlorosilane, vinyltrichlorosilane,
Vinylmethylphenylchlorosilane, allyl triethoxy
Sisilane, 3-allylaminopropyltrimethoxysila
Allyl diacetoxymethylsilane, allyl triacetate
Toxisilane, allylbis (dimethylamino) methylsi
Orchid, allylmethyldichlorosilane, allyldimethylc
Lorosilane, allyltrichlorosilane, methallylphenyl
Rudichlorosilane, β- (meth) acryloxyethyl
Limethoxysilane, β- (meth) acryloxyethyl
Liethoxysilane, γ- (meth) acryloxypropyl
Trimethoxysilane, γ- (meth) acryloxypropyl
Lutriethoxysilane, γ- (meth) acryloxypro
Pyrmethyldimethoxysilane, γ- (meth) acryloxy
Cypropylmethyldichlorosilane, γ- (meth) acryl
Roxypropyl tris (β-methoxyethoxy) silane
Etc.]. Preferably an alkoxysilyl group
(C such as methoxysilyl group and ethoxysilyl group _1-4A
A polymerizable unsaturated monomer having a alkoxysilyl group).
You.

(B) Other polymerizable unsaturated monomers Other polymerizable unsaturated monomers include a polymerizable unsaturated monomer having an ion-forming group, a (meth) acrylic monomer, Aromatic vinyls and the like can be used as components for copolymerization. However, from the viewpoint that the obtained copolymer is easily emulsified, a polymerizable unsaturated monomer having at least one ion-forming group is used for copolymerization. It is preferable to use it as a component. The content of the polymerizable unsaturated monomer having an ion-forming group in other polymerizable unsaturated monomers is, for example, usually 1 to 20% by weight, preferably 2 to 10% by weight.

Examples of the ion-forming group include a cation-forming group such as an amino group and an imino group, and an anion-forming group such as a carboxyl group. Examples of the polymerizable unsaturated monomer having a cation-forming group include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminopropyl (meth) acrylate, and dimethylamino. Ethyl (meth) acrylamide,
(Meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxyethyltrimethylammonium sulfate and the like. Such monomers having a cation-forming group can be used alone or in combination of two or more.

Examples of the polymerizable unsaturated monomer having an anion-forming group include carboxyethyl (meth) acrylate, carboxypropyl (meth) acrylate,
Vinyl carboxylic acid [(meth) acrylic acid, crotonic acid,
Sorbic acid, maleic acid, itaconic acid, cinnamic acid, etc.), vinyl sulfonic acid [vinyl sulfonic acid, allyl sulfonic acid, vinyl toluene sulfonic acid, styrene sulfonic acid, etc.], (meth) acryl sulfonic acid [(meth) acrylic] Sulfoethyl acid, sulfopropyl (meth) acrylate], (meth) acrylamidosulfonic acid [2-acrylamido-2-methylpropanesulfonic acid, etc.] and the like. Such monomers having an anion-forming group can be used alone or in combination of two or more.

The other polymerizable unsaturated monomers other than the polymerizable unsaturated monomer having an ion-forming group are not particularly limited, and may be selected from known polymerizable unsaturated monomers by copolymers. It is appropriately selected according to the use to which the composition is applied. Examples of such polymerizable unsaturated monomers include (meth) acrylic monomers, aromatic vinyls, vinyl esters, halogen-containing vinyls, vinyl ethers (eg, vinyl ethyl ether, etc.), vinyl ketones (Eg, methyl vinyl ketone, etc.), vinyl heterocyclic compounds (eg, N
N such as vinylpyrrolidone and N-vinylimidazole
-Vinyl compounds, N-vinylpyridine, etc.), olefin monomers (eg, ethylene, propylene, etc.), allyl compounds (eg, allyl esters such as allyl acetate, etc.)
And the like. These polymerizable unsaturated monomers can be used alone or in combination of two or more.

The (meth) acrylic monomer of the polymerizable unsaturated monomer includes, for example, (meth) acrylate, (meth) acrylate
Acrylamides, (meth) acrylonitrile and the like are included. (Meth) acrylate includes, for example, alkyl (meth) acrylate [for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate. )
Acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, _C1-18 alkyl (meth) acrylate such as lauryl (meth) acrylate, etc., cyclo Alkyl (meth) acrylate [eg, cyclohexyl (meth) acrylate, etc.], aryl (meth) acrylate [eg, phenyl (meth) acrylate, etc.], aralkyl (meth) acrylate [eg, benzyl (meth) acrylate, etc.], hydroxyalkyl (meth) acrylates [e.g., 2-hydroxyethyl, 2-hydroxypropyl ((meth) hydroxyalkyl _{-C 2-4} alkyl acrylates such as (meth) acrylate, etc.], glycidyl (meth) acrylate, dialkyl Arylamino - alkyl (meth) acrylates [for example, 2- (dimethylamino) ethyl (meth) acrylate, 2- (diethylamino) ethyl (meth) di _{C 1-4} alkylamino -C such acrylates
_2-4 alkyl (meth) acrylate, etc.].

(Meth) acrylamides include, for example,
(Meth) acrylamide, hydroxyalkyl (meth)
Acrylamide, [eg, N-hydroxy-C _1-4 alkyl (meth) acrylamide such as N-methylol (meth) acrylamide, etc.], alkoxyalkyl (meth)
Acrylamide, [for example, N-methoxymethyl (meth)
Acrylamide, _{N-C 1-4} alkoxy _{-C 1-4}
Alkyl (meth) acrylamide, etc.], and diacetoxy (meth) acrylamide.

Preferred (meth) acrylic monomers include, for example, methacrylates [for example, C _1-18 alkyl (meth) acrylate, hydroxy-C _2-4 alkyl (meth) acrylate, glycidyl (meth) acrylate; Di C _1-4 alkylamino-C _2-4 alkyl (meth) acrylate), (meth) acrylamides and the like. More preferred (meth) acrylic monomers include C _2-10 alkyl acrylate and C _2-10
1-6 alkyl methacrylate, hydroxy-C
_2-3 alkyl (meth) acrylate, glycidyl (meth) acrylate, di C _1-3 alkyl amino-C
_2-3 alkyl (meth) acrylate and the like.

The aromatic vinyls include, for example, styrene,
α-Methylstyrene, vinyltoluene and the like are included, and styrene is often used. Vinyl esters include, for example, vinyl acetate, vinyl propionate, vinyl versatate (VeoVa), and the like. Halogen-containing vinyls include, for example, vinyl chloride, vinylidene chloride, and the like.

As the other polymerizable unsaturated monomer, a hard monomer [eg, a glass transition temperature of 80 to 120 ° C. such as methyl (meth) acrylate, styrene, etc.]
Monomer component that forms a homopolymer having a glass transition temperature of about −85 ° C. to about 10 ° C., such as a C _2-10 alkyl acrylate. Component].

As described above, the content of the polymerizable unsaturated monomer having a hydrolyzable silyl group in the hydrolyzable silyl group-containing acrylic copolymer (B) is usually from 0.5 to 0.5.
It is 15% by weight, preferably 1 to 12% by weight, more preferably 2 to 10% by weight. If the content of the monomer is less than 0.5% by weight, there may be a problem that the water resistance and strength of the ink receiving layer are deteriorated.
If it exceeds 3, there may be a problem that the polymerization stability of the acrylic copolymer (B) and the storage stability when emulsified are reduced.

As a polymerization method for obtaining the hydrolyzable silyl group-containing acrylic copolymer (B), known polymerization methods such as emulsion polymerization can be used. Then, a method of obtaining an aqueous resin composition by adding water to the obtained resin solution to emulsify and then removing the solvent used for the solution polymerization is preferably used. That is, the above-mentioned copolymer components are mixed and copolymerized in an appropriate organic solvent, and the obtained polymer is dissolved or dispersed in water using a base or an acid described below. The polymerization operation may be a batch type or a continuous type.

Examples of the organic solvent used for the solution polymerization include alcohols (eg, ethanol, isopropanol, n-butanol, etc.), aromatic hydrocarbons (eg, benzene, toluene, xylene, etc.), and aliphatic hydrocarbons (eg, Pentane, hexane, heptane, etc.), alicyclic hydrocarbons (eg, cyclohexane, etc.), esters (eg, ethyl acetate, n-butyl acetate, etc.), ketones (eg, acetone, methyl ethyl ketone, etc.), ethers (eg, diethyl ether) Tail, dioxane, tetrahydrofuran, etc.). These organic solvents may be used alone or in combination of two or more. As the organic solvent, an alcohol such as isopropanol, an aromatic hydrocarbon such as toluene, and a ketone such as methyl ethyl ketone are usually used.

The amount of the organic solvent used is not particularly limited, and is, for example, usually 0.1 / 1 to 5/1, preferably 0, in terms of weight ratio of the amount of the organic solvent to the total amount of the polymerizable unsaturated monomers. .
It can be selected from the range of 5/1 to 2/1.

In the solution polymerization, the polymerization may be started by irradiation with an electron beam or ultraviolet rays, but the polymerization is often started using a polymerization initiator. Examples of the polymerization initiator include, for example, azo compounds [for example, azobisisobutyronitrile, 2,2-azobis (2,4-dimethylvaleronitrile, azobiscyanovaleric acid), 2,2-azobis (2-amidinopropane) hydro Chloride, 2,2
Azobis (2-amidinopropane) acetate, etc.),
Inorganic peroxides (for example, persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate, hydrogen peroxide), organic peroxides (for example, benzoyl peroxide, di-
t-butyl peroxide, cumene hydroxy peroxide, di (2-ethoxyethyl) peroxydicarbonate] and redox catalyst [for example, sulfite or bisulfite (for example, alkali metal salt, ammonium salt, etc.), L-ascorbic acid] , A catalyst system comprising a combination of a reducing agent such as erythorbic acid and an oxidizing agent such as a persulfate (for example, an alkali metal salt or an ammonium salt) or a peroxide]. The polymerization initiators can be used alone or in combination of two or more.

The amount of the polymerization initiator used is not particularly limited.
For example, 0.00 to the total weight of the polymerizable unsaturated monomer.
It can be selected from the range of 1 to 20% by weight, preferably 0.01 to 10% by weight, particularly preferably 0.1 to 10% by weight.

The reaction temperature in the solution polymerization is not particularly limited, and is, for example, 50 to 150 ° C., preferably 70 to 1
30 ° C. The reaction time is not particularly limited, and is, for example, 1 to 10 hours, preferably 2 to 7 hours. The end point of the polymerization can be confirmed by disappearance of the double bond absorption (1648 cm ^-1 ) in the infrared absorption spectrum or reduction of the unreacted monomer by using gas chromatography.

In the solution polymerization, chain transfer agents such as alcohols such as catechol, thiols, and mercaptans (for example, n-lauryl mercaptan, n-dodecyl mercaptan, and so on) are used to adjust the molecular weight of the polymer. t-dodecylmercaptan, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane) and the like may be used.

In the case where the acrylic copolymer is copolymerized, from the viewpoint of improving the mechanical stability of the dispersion, the copolymerization is carried out in the presence of part or all of the inorganic fine particles blended in the dispersion. May be performed. The amount of the inorganic fine particles to be present in the polymerization solution is preferably 3 to 80 parts by weight, particularly preferably 3 to 30 parts by weight, based on 100 parts by weight of the polymerizable unsaturated monomer contained.

When the copolymer has a cationic group such as an amino group, an imide group or a cation-forming group, the use of an acid improves the hydrophilicity and makes it easy to dissolve or emulsify the copolymer. it can. Such acids include, for example, inorganic acids (eg, hydrochloric acid, phosphoric acid, sulfuric acid, nitric acid, etc.),
Organic acids [for example, saturated aliphatic monocarboxylic acids such as formic acid, acetic acid, and propionic acid; saturated aliphatic polycarboxylic acids such as oxalic acid and adipic acid; unsaturated aliphatic polycarboxylic acids such as (meth) acrylic acid; Unsaturated aliphatic polycarboxylic acids such as acids and itaconic acids; aliphatic oxycarboxylic acids such as lactic acid and citric acid]. The amount of the acid used is not particularly limited, and can be selected, for example, in the range of 0.3 / 1 to 1.5 / 1 in terms of acid / cationic group (molar ratio) with respect to the total of the cationic groups.

When the copolymer has an acidic group such as a carboxyl group, the use of a base improves the hydrophilicity, and can easily dissolve or emulsify the copolymer. Such bases include, for example, organic bases (eg, alkylamines such as triethylamine, cyclic amines such as morpholine, alkanolamines such as triethanolamine,
Pyridine, etc.), inorganic bases (eg, ammonia, alkali metal hydroxides, etc.) and the like. The amount of the base to be used is not particularly limited, and for example, can be selected from the range of 0.3 / 1 to 1.5 / 1 in terms of base / acid group (molar ratio) with respect to the total of the acid groups.

Emulsification of the copolymer obtained by solution polymerization can be carried out in the presence or absence of an organic solvent. When the copolymer is emulsified in water in the presence of an organic solvent, additives (eg, emulsifier, pH adjuster, acid, etc.) are added to the organic solution containing the copolymer, and then water is added to emulsify the copolymer. I do. In this case, it is preferable that water is gradually added by dropping or the like. In addition, the emulsification temperature is preferably lower, and for example, can be selected from the range of 5 to 70 ° C, preferably 10 to 50 ° C. As the organic solvent, a water-soluble organic solvent (for example, an alcohol such as isopropanol) is often used.

When the copolymer is emulsified in water in the presence of an organic solvent, the organic solvent is removed after the emulsification by evaporation or the like. The removal of the organic solvent, for example, at a temperature of 5 to 80C,
It is often performed under normal pressure or reduced pressure (for example, 0.0001 to 1 atm). When the organic solvent is removed before emulsifying the copolymer, an organic solvent having a low boiling point (for example, a ketone such as methyl ethyl ketone) is often used.

The average particle size of the polymer particles in the aqueous emulsion obtained as described above is, for example, from 0.01 to 2 μm as long as the dispersion stability, adhesion and the like are not impaired.
m, preferably 0.01-1 μm, more preferably 0.1 μm.
01 to 0.5 μm, more preferably 0.01 to 0.3
It can be selected from the range of μm.

An aqueous resin composition obtained by emulsifying the hydrolyzable silyl group-containing acrylic copolymer (B) is as follows:
It may be an aqueous solution or an aqueous emulsion (aqueous polymer emulsion). Such an aqueous resin composition is an aqueous resin composition configured without using a special cross-linking resin such as a cross-linked product of an acrylic silicone oligomer containing a hydrolyzable alkoxysilyl group. high. In addition, by using this water-based resin composition, it is possible to obtain a coating liquid having low fear of air pollution, poisoning, fire and the like and good workability.

The hydrolyzable silyl group-containing acrylic copolymer (B) may be added, if necessary, to stabilizers such as lubricants, antioxidants, ultraviolet absorbers, heat stabilizers, radical scavengers, etc. Various known additives such as a quencher, an antistatic agent, a plasticizer, a thickener, and an antifoaming agent may be added.

Light stabilizers and ultraviolet absorbers such as hindered amine compounds, benzoate compounds, benzotriazoles, benzophenones and formamidines are effective for imparting and improving weather resistance.

When the copolymer obtained by solution polymerization is emulsified, from the viewpoint of improving the mechanical stability of the dispersion, some or all of the inorganic fine particles to be added to the dispersion are added to the water to be added. It may be mixed.

3. Aqueous solvent (C) As the aqueous solvent (C), various known solvents such as water and alcohols can be used, but water or a mixed solvent containing water as a main component is preferably used.

4. Dispersion The dispersion used in the present invention is obtained by mixing the inorganic fine particles (A), the hydrolyzable silyl group-containing acrylic copolymer (B) and the aqueous solvent (C). The mixing method is not particularly limited, and a known method can be used.

The mixing ratio of the inorganic fine particles (A) and the acrylic copolymer (B) is 97 to 70/3 in terms of solid content.
-30% by weight, more preferably 95-75 / 5-5-25% by weight. When the amount of the inorganic fine particles exceeds 97% by weight, the film-forming property tends to decrease, and when the amount is less than 40% by weight, the quick-drying property and the ink absorbability decrease.

The ratio of the solid content of the dispersion is adjusted depending on the amount of the aqueous solvent to be added, but is usually 1 to 40% by weight, preferably 5 to 25% by weight. When the ratio of the solid content exceeds 40% by weight, the mechanical stability of the dispersion liquid decreases, and the solid content sediments. When the ratio is less than 1% by weight, it is difficult to form an ink receiving layer having a sufficient thickness, The drying load increases and productivity decreases.

5. Composition for Inkjet Recording Material The composition for inkjet recording material of the present invention is pulverized and dispersed in a dispersion containing inorganic fine particles (A), a hydrolyzable silyl group-containing acrylic copolymer (B) and an aqueous solvent (C). The inorganic fine particles (A) can be obtained by performing the treatment so that the average particle size of the inorganic fine particles (A) is 0.5 μm or less.

In the above-mentioned pulverization and dispersion treatment, preferably, inorganic fine particles having an average particle diameter of 1 to 50 μm before the treatment are pulverized and dispersed so that the average particle diameter becomes 0.5 μm or less after the treatment. The average particle diameter of the inorganic fine particles after the treatment is usually 0.01 to 0.5 μm, preferably 0.0 to 0.5 μm.
3 to 0.3 μm, more preferably 0.05 to 0.2 μm
It is. If the average particle size of the inorganic fine particles is less than 0.01 μm, the void volume of the ink receiving layer is insufficient, and if it exceeds 0.5 μm, the gloss and transparency of the ink receiving layer are reduced.

The method of pulverizing and dispersing the dispersion is not particularly limited, and a known high-pressure disperser, such as a high-pressure jet emulsifier of BEE Japan, a jet stream of Mitamura Riken Kogyo Co., Ltd. A mixer, a nanomanizer of Nanomanizer Co., Ltd. or the like can be used.
Process pressure is usually 300~4000kg / cm ^2, preferably 500~2000kg / cm ^2. The number of treatments is not particularly limited, and can be appropriately selected from 1 to 30 times.

The composition for an ink jet recording material of the present invention may optionally contain other components such as a polymer having no crosslinkable group or an aqueous emulsion containing the polymer (for example, ethylene- (Vinyl acetate copolymer emulsion, vinyl acetate emulsion, etc.).

Further, the composition for an ink jet recording material of the present invention may contain powders (eg, pigments). As the powder, for example, inorganic powder (white carbon,
Fine-grained calcium silicate, zeolite, magnesium aminosilicate, calcined siliceous earth, fine-grained magnesium carbonate, fine-grained alumina, talc, kaolin, delamikaolin,
Clay, heavy calcium carbonate, light calcium carbonate, magnesium carbonate, titanium dioxide, aluminum hydroxide,
Mineral powders such as calcium hydroxide, magnesium hydroxide, magnesium silicate, calcium sulfate, sericite, bentonite, and smectite, etc.), and organic powders (polystyrene resin, urea resin, melamine resin, benzoguanamine resin, etc.) Organic particles such as non-crosslinked organic fine particles and fine hollow particles). One or more of these powders may be appropriately selected and used in combination. In the case where the powdery particles are contained, a hydrophilic polymer such as a saponified vinyl acetate copolymer can be used as the binder resin. The ratio of the granular material to the binder resin is 0. 0 to 100 parts by weight of the binder resin.
It is 1 to 80 parts by weight, preferably 0.2 to 50 parts by weight.

Furthermore, the composition for an ink jet recording material of the present invention may be added to a conventional ink fixing agent or a crosslinking agent for the purpose of ink jet recording properties and storage stability of the recording medium, as long as the properties of the present invention are not lost. Agents, light stabilizers, UV absorbers,
Additives such as an anti-blocking agent and a film-forming aid may be added.

The composition for an ink jet recording material of the present invention obtained as described above has excellent mechanical stability.
For example, a mechanical stability test according to JIS K 6392 indicates that 15
Stable under kgf load conditions.

6. Support The support used in the present invention, on which the ink receiving layer is formed, may be opaque, translucent or transparent depending on the application. The material of the support is not particularly limited, and for example, paper, coated paper, nonwoven fabric, plastic film, synthetic paper, and the like can be used. Furthermore, in the shape of the support,
There is no particular limitation, and it may have a three-dimensional shape.

Examples of the polymer constituting the plastic film and the synthetic paper include polyolefin such as polyethylene and polypropylene, ethylene-vinyl acetate copolymer, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, and poly (meth) acryl. Acid esters, polystyrene, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, cellulose derivatives such as cellulose acetate, polyesters (polyalkylene terephthalate such as polyethylene terephthalate and polybutylene terephthalate,
Polyalkylene naphthalate such as polyethylene naphthalate, polybutylene naphthalate, etc.), polycarbonate, polyamide (polyamide 6, polyamide 6/6, polyamide 6/10, polyamide 6/12, etc.), polyester amide, polyether, polyimide, polyimide Examples thereof include amides and polyether esters, and copolymers, blends and cross-linked products thereof may be used.

As the polymer constituting the above-mentioned film or synthetic paper, polyolefin (especially polypropylene), polyester (especially polyethylene terephthalate, etc.), polyamide and the like are usually used, and particularly, such as mechanical strength, workability and cost. From the viewpoint, polyester (particularly, polyethylene terephthalate) is preferred. As the paper or coated paper, for example, high-quality paper, art paper, RC paper, or the like can be used.

The thickness of the support can be selected according to the application.
Usually, it is about 5 to 500 μm, preferably about 10 to 300 μm. If necessary, conventional additives such as a sizing agent, an antioxidant, an ultraviolet absorber, a heat stabilizer, a lubricant, and a pigment may be used inside or on the surface of the support.

In order to improve the adhesion to the ink receiving layer, a surface treatment such as a corona discharge treatment or an undercoat treatment may be performed.

7. Method for Producing Recording Object or Recording Sheet The recording object or recording sheet of the present invention is obtained by applying a coating liquid comprising the composition for an ink jet recording material of the present invention to at least one surface of the above-mentioned support. Can be produced. The coating solution is formed by a conventional casting or coating method, for example, a roll coater, an air knife coater, a blade coater, a rod coater, a bar coater, a comma coater, a gravure coater, a silk screen coater method, or the like. Is cast or applied. The ink receiving layer can be formed by applying a coating solution containing the above components to at least one surface of the support and drying the coating solution. Further, if necessary, after the application liquid is applied, a crosslinked ink receiving layer may be formed by heating at an appropriate temperature selected from the range of 50 to 150 ° C. Incidentally, a porous layer, an anti-blocking layer, a lubricating layer, an antistatic layer and the like may be formed on the ink receiving layer, if necessary.

The thickness of the ink receiving layer can be selected according to the application, and is usually 3 to 50 μm, preferably 5 to 30 μm,
More preferably, it is 6 to 30 μm.

[0069]

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples. Unless otherwise specified, the parts or percentages of the mixing ratio are based on weight, and the weights of the acrylic copolymer A and the inorganic fine particles B indicate solid content-converted values.

Silica Particles The following silica particles were used in Examples and Comparative Examples.・ Silica 1 Gas layer method silica Nippon Aerosil Co., Ltd. A
300 (average particle size 0.007 μm) ・ Silica 2 wet method silica (gel type) Mizusawa Chemical Industry Co., Ltd. P-78A (average particle size 3.3 μm) ・ Silica 3 wet method silica (precipitation type) Mizusawa Chemical Industry ( P-526 (average particle size: 3.0 μm)

Evaluation Method The inorganic fine particle dispersions obtained in Examples and Comparative Examples and the recording sheets on which an ink receiving layer was formed using the dispersions were evaluated as follows. (Mechanical Stability) Using a Marlon tester, the degree of precipitation of coagulated material was visually evaluated when 15 kgf was applied and the mixture was stirred at 1000 rpm for 15 minutes. ：: No solidified product was precipitated. ×: A solidified product is precipitated. (Ink Absorption) An ISO standard image (fruit) was printed on the produced recording paper by using EPSON PM-770C with the paper setting being photo glossy paper. The printed image was visually evaluated. ：: No blurring or unevenness is observed in the image. ×: Blurring or unevenness is observed in the image. (Water resistance) A water drop was dropped on the printed image, left for 1 minute, and the state of the image after wiping off the water drop with paper was visually evaluated. ：: No change was observed at all as compared to before dropping of water droplets. Δ: Slight traces of water drops are observed. ×: The image is clearly thin. (Glossiness) HANDY GLO manufactured by Nippon Denshoku Industries Co., Ltd.
The 85 ° gloss was measured and evaluated using SSMETER PG-1M. (Coating film strength) The prepared recording paper was bent, and the powder falling of the coating film was visually evaluated. ：: No powder drop was observed at all. ×: Powder drop was clearly observed.

[Synthesis Example 1] Acrylic copolymer 1 (containing a hydrolyzable silyl group) In a 2000 ml reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, nitrogen inlet tube and thermometer, isopropanol (hereinafter referred to as " 219 parts and 1.23 parts of azoisobutyronitrile (AIBN) were added and dissolved by stirring, and the mixture was heated to 80 ° C. 140 parts of methyl methacrylate (hereinafter abbreviated as "MMA") as a copolymer component, n-
Butyl acrylate (hereinafter abbreviated as “BA”) 116
Part, γ-methacryloxypropyltrimethoxysilane (manufactured by Nippon Unicar Co., Ltd., A-174: hereinafter referred to as “A-17
4 ". ) 18 parts and 6.5 parts of acrylic acid were mixed and dropped into the flask over about 4 hours. After dropping, 0.25 parts of AIBN and IPA were added as additional polymerization catalysts.
A solution consisting of 25 parts was added dropwise, and the reaction was continued for another 2 hours to complete the polymerization. After completion of the polymerization, 22 parts of 25% ammonia water was added to the flask, and then 7 parts of ion-exchanged water was added.
After dropping 05 parts over about 1 hour, IPA was evaporated by a rotary evaporator to obtain an anionic acrylic copolymer. The properties of the obtained acrylic copolymer 1 are as follows: nonvolatile content 36%, viscosity 60 mPa · s,
pH was 7.5.

[Synthesis Example 2] Acrylic copolymer 2 (containing a hydrolyzable silyl group) was composed of 140 parts of MMA, 116 parts of BA,
174 6.5 parts and diethylaminoethyl methacrylate (DEAEMA) 5.0 parts.
Synthesis Example 1 except that 23 parts of an 88% formic acid aqueous solution was added.
By synthesizing in the same manner as described above, a cationic acrylic copolymer was obtained. The properties of the obtained acrylic copolymer 2 are as follows:
Non-volatile content 30%, viscosity 100 mPa · s, pH 5.5
Met.

[Synthesis Example 3] Acrylic copolymer 3 An anionic acrylic copolymer was obtained in the same manner as in Synthesis example 1 except that A-174 was not added as a copolymer component. The properties of the obtained acrylic copolymer 3 were as follows: nonvolatile content 35%, viscosity 50 mPa · s, pH
7.8.

[Synthesis Example 4] Acrylic copolymer 4 157 parts of ion-exchanged water was placed in a 2000 ml reaction vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a nitrogen inlet tube and a thermometer, and the interface was stirred. 2.34 parts of an activator (sodium alkyl sulfosuccinate Eleminol JS-2 manufactured by Sanyo Chemical Co., Ltd.) and 0.77 of ammonium persulfate
Was added and dissolved. MMA 11 as a copolymer component
1.1 parts, BA 80.8 parts, and acrylic acid 6.06 parts were mixed, and this mixed solution was mixed with Eleminol JS-2 4.67.
And an aqueous solution of 58.47 parts of ion-exchanged water to form a pre-emulsion. After heating the reaction solution to 60 ° C., the pre-emulsion and 53 parts of a 0.688% aqueous sodium thiosulfate solution were respectively dropped into the reaction vessel over about 4 hours using a dropping funnel. 2 more after the end of dropping
The reaction was continued for an hour to obtain an anionic acrylic copolymer. The properties of the obtained acrylic copolymer 4 were a nonvolatile content of 39%, a viscosity of 80 mPa · s, and a pH of 8.0.

[Examples 1 to 6, Comparative Examples 1 to 6] Silica (1 to 3) and acrylic copolymer (1 to 4) were gradually added to 400 parts by weight of ion-exchanged water with good stirring. The mixed solution is subjected to a high-pressure homogenizer (manufactured by Sanwa Industry Co., Ltd.)
Was dispersed twice at a pressure of 250 kg / cm ² to prepare an aqueous silica dispersion. The average particle size of the silica in the dispersion was all 0.5 μm or less. Table 1 shows the evaluation results of the mechanical stability of each aqueous silica dispersion.

Comparative Example 7 Silica 2 and acrylic copolymer 3 were prepared in 400 parts by weight of ion-exchanged water, and a silica aqueous dispersion was prepared without using a high-pressure homogenizer. The average particle size of the silica in the dispersion was 3.0 μm. Table 1 shows the evaluation results of the mechanical stability of the aqueous silica dispersion.

[Preparation of Recording Paper] Each of the above aqueous dispersions of silica was applied to art paper having a basis weight of 180 g / m ^{2 to} a thickness of 50 g / m ^2.
It was applied to a thickness of μm and dried at room temperature to prepare a recording sheet. Table 1 shows the evaluation results of the characteristics of the recording paper.

[0079]

[Table 1]

As is evident from Table 1, the composition for an ink jet recording material of the present invention has excellent mechanical stability, and the ink receiving layer obtained by using the composition has a high glossiness and an ink absorbing property. Excellent water resistance and coating strength.

[0081]

The composition for ink jet recording of the present invention has excellent mechanical stability, and the ink receiving layer formed by using the composition is sharp, glossy, ink-absorbing, drying, and water-resistant. Excellent.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 3/36 C08L 43/04 C08L 43/04 B41J 3/04 101Y F-term (Reference) 2C056 FC06 2H086 BA15 BA53 BA59 BA60 BA62 4F070 CA02 CA03 CB03 4J002 BC021 BG011 BG031 BG071 BG101 BG121 BH021 BQ001 DE146 DE236 DJ016 FA086 FD016 HA07 4J100 AB02P AB03P AB04P AB07P AB07Q AC03P AC04P AG02P AG04P AG06P AJ01P AJ02P AJ08P AJ09P AL02P AL03P AL04P AL05P AL08P AL08Q AL09P AL11P AM15P AM21P AN05Q AP01P AP16Q AQ08P AQ12P BA03P BA04Q BA05P BA05Q BA06Q BA10Q BA16P BA28Q BA31P BA32P BA56P BA75Q BA77Q BA85Q BB01Q BC04P BC43Q CA04 FA19 JA07

Claims (6)

[Claims] 1. An ink jet recording material composition comprising a dispersion containing inorganic fine particles (A), a binder resin (B) and an aqueous solvent (C), wherein the binder resin (B) is a hydrolyzable silyl group-containing acrylic. A composition for an ink jet recording material, which is a copolymer, and further comprising subjecting the dispersion to a pulverization and dispersion treatment so that the average particle size of the inorganic fine particles (A) is 0.5 μm or less. 2. The inorganic fine particles (A) have an average particle diameter of 1 to 50.
2. The composition for an ink jet recording material according to claim 1, wherein the composition is silica having a particle diameter of μm. 3. The binder resin (B) contains 0.5 to 15% by weight of a polymerizable unsaturated monomer having a hydrolyzable silyl group.
And 99.5 to 85% by weight of another polymerizable unsaturated monomer
And a water-soluble solvent (C) is added to a resin solution obtained by solution polymerization to form an emulsion, and the polymerization solvent is removed. 2. The composition for an ink jet recording material according to claim 1, wherein the composition is formed into an aqueous resin composition. 4. The mixing ratio of the inorganic fine particles (A) and the binder resin (B) is such that (A) is 70 in terms of solid content.
2. The composition for an ink jet recording material according to claim 1, wherein the content of (B) is 30 to 3% by weight with respect to about 97% by weight. 5. The hydrolyzable silyl group-containing acrylic copolymer is a cationic resin.
3. The composition for an ink jet recording material according to item 1. 6. A recording medium or a recording sheet comprising an ink receiving layer formed of the composition for an ink jet recording material according to claim 1 on a support.