JP2003048368A - Ink jet recording resin composition and recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording resin composition useful to manufacture a recording sheet which can form a recording layer having good environmental gas resistance such as an ozone resistance or the like and which has excellent ink absorbability and printing image quality and to provide the recording sheet. SOLUTION: The ink jet recording resin composition comprises the recording layer formed on a base. The resin composition contains 3 to 60 mass% of a copolymer emulsion (a) and 40 to 97 mass% of inorganic fine particles (b) in such a manner that a content (CX) of a free emulsion (c) in the copolymer emulsion (a) satisfies formula (1) of 0 wppm<=CX/AX<10,000 wppm, wherein CX is the content of the free emulsion (c) in the emulsion (a), AX is a copolymer component amount of the copolymer emulsion, and wppm is a mass ppm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for ink jet recording and a recording sheet for forming a recording layer on a substrate such as paper or a plastic film, and more particularly to environmental gas resistance such as ozone resistance. The present invention relates to a resin composition for inkjet recording, which is useful for producing a recording sheet which is capable of forming a recording layer having good properties and is excellent in ink absorbency and print image quality, and a recording sheet formed from these.

[0002]

2. Description of the Related Art Ink jet recording systems are rapidly becoming popular in recent years because they are inexpensive, can be easily converted into full colors, have low noise, and have excellent printing quality. In the inkjet recording, a water-based dye ink is mainly used in terms of safety and recording suitability, and recording is performed by ejecting ink dots from nozzles toward a recording sheet. Therefore, the recording sheet is required to absorb the ink promptly. In addition, it has become possible to obtain a print comparable to that of a silver salt photographic image by increasing the number of colors of ink and reducing the particle size of ink dots, and the recording speed has also been increased. As described above, although the recording apparatus and the recording method have been improved, correspondingly, the inkjet recording material is required to have a high level of characteristics.

Various recording papers have been conventionally 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, various bases such as transparent or opaque plastic film, synthetic paper, and RC paper in which both sides of the paper are coated with plastic. A recording sheet in which a recording layer is provided on the material is used.

The recording layer is roughly classified into a swelling type recording layer mainly composed of a hydrophilic resin and a so-called void type recording layer in which a void layer is formed mainly of a fine particle component such as silica to form a recording layer. be able to. As these recording layers, for example, Japanese Patent Laid-Open No. 63-115780 discloses that a quaternary ammonium salt of (meth) acrylic acid alkyl and / or (meth) acrylamidoalkyl quaternary ammonium salt containing synthetic silica is used. Japanese Unexamined Patent Publication (Kokai) No. 6-227114 discloses a coalescence formed from an aqueous composition containing a pigment containing finely divided silica and a zwitterionic latex as main components.

An ink jet recording material having a swelling type recording layer is a silver salt photograph having a very high gloss and color density after completely evaporating water and an ink solvent composed of a high boiling point organic solvent (such as glycerin and ethylene glycol). However, the ink absorption rate (drying rate) is slower than that of the void-type recording layer, and in some cases, it may take several hours to several hours after printing due to the high boiling point solvent in the ink solvent. The recording layer remains swollen and wet for a period of time, and there is a drawback that it is not sticky or cannot be overlaid. In addition, in a portion where the printing ink amount is large, there are problems that the ink absorbency is insufficient and image defects such as beading occur, and it is difficult to achieve both ink absorbency and water resistance. In particular, as high-speed printers, use of photo inks, and high image quality such as high-resolution printing of 1000 dpi or more progress, slow ink absorption speed (drying speed) becomes a problem, and a void type recording layer having excellent ink absorbability is provided. Ink jet recording materials are becoming mainstream.

On the other hand, an ink jet recording material having a void type recording layer exhibits high ink absorbability because the voids absorb ink. For this reason, image defects such as beading are unlikely to occur, and since water-insoluble inorganic fine particles are the main component, the water resistance is high. In addition, if the recording layer thickness is set so as to ensure a sufficient ink absorption capacity, even if ink solvent such as a high boiling point organic solvent remains in the void, the surface is apparently dry immediately after printing. It has a drying speed that can be touched and overlapped. However, despite these advantages,
There is a problem that the gloss is too low due to the presence of voids.

As the void type recording layer as described above,
For example, JP-A-60-219084 and JP-A-63-1
70074, JP-A-2-43083, JP-A-4-9
3284, JP-A-7-137431, and JP-A-8-
In Japanese Patent Laid-Open No. 197832, the use of various inorganic particles is disclosed. The coating liquid for forming such a void type recording layer on the substrate is formed between the inorganic fine particles if the content of the binder resin relative to the inorganic fine particles is too large in order to improve the glossiness. There is a problem in that the ink absorbency cannot be sufficiently obtained by blocking the voids. Therefore, a formulation having a low binder resin content is used. However, if the proportion of the inorganic fine particles is increased too much in order to secure the ink absorbency and the absorption capacity, the strength of the coating film forming the recording layer becomes weak and becomes brittle, and the inorganic fine particles may come off or crack. This causes a problem that a surface having high flatness cannot be formed and a clear printed image cannot be obtained.

In order to solve the above-mentioned problems and the like, synthetic resin emulsions have come to be preferably used in place of hydrophilic resins such as polyvinyl alcohol as one of the binders which does not hinder the formation of voids between inorganic fine particles. There is. A recording sheet that solves such problems is
A clear printed image is formed by the ink ejected onto the recording layer permeating into the voids of the recording layer or evaporating, and the surface becomes apparently dry immediately after printing and can be touched or overlaid. Has a drying rate.

Further, various performances are required for the formed print image. Among these required performances, many proposals regarding storage stability of printed images have been made, but they have not been sufficiently solved. In particular, with regard to light resistance, which is storage stability against discoloration due to light, a method of increasing the light resistance of the ink itself or a method of adding an additive such as an ultraviolet absorber to the recording layer has been proposed and improved. There is. However, the printed image is subject to fading due to the influence of environmental gas such as ozone resistance, and there is still much room for improvement in improving the environmental gas resistance. Therefore, a recording layer having good environmental gas resistance such as ozone resistance can be formed, and a recording layer useful for producing a recording sheet excellent in ink absorbency, ink drying property, and print quality (printing quality) can be obtained. There is a strong demand for the development of resin compositions and recording sheets using the same.

[0010]

In view of the problems of the prior art, an object of the present invention is to provide an ink jet recording resin composition for forming an ink jet recording layer on a substrate such as paper or a plastic film, which is ozone resistant. And a recording sheet formed from the same, which is useful in the production of a recording sheet which is capable of forming a recording layer having excellent resistance to environmental gas such as properties and which is excellent in ink absorption and print image quality (or print quality) To provide.

[0011]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to achieve the above-mentioned object, and as a result, in an ink jet recording resin composition for forming a recording layer on a substrate, In the resin composition, the copolymer emulsion (a) and the inorganic fine particles (b) are blended in a specific ratio, and the free emulsifier (c) content (CX) in the copolymer emulsion (a) is specified. When the relational expression is satisfied (that is, less than 1% by mass), a recording layer having excellent environmental gas resistance such as ozone resistance can be formed, and a recording sheet excellent in ink absorption and print image quality (or print quality) can be obtained. The inventors have found that an ink jet recording resin composition useful for production can be obtained, and completed the present invention.

That is, according to the first aspect of the present invention, in the ink jet recording resin composition for forming a recording layer on a substrate, the ink jet recording resin composition is a copolymer emulsion based on the total amount of the composition. (A) 3 to 60 mass% and inorganic fine particles (b) 40 to 97 mass%, and the free emulsifier (c) content (CX) in the copolymer emulsion (a) has the following relationship. Provided is a resin composition for inkjet recording, which satisfies the formula. 0 wppm ≦ CX / AX <10000 wppm (Formula 1) (where CX is the content of the free emulsifier (c) in the copolymer emulsion (a), and AX is the copolymer weight of the copolymer emulsion (a). (The amount of combined components is shown, and wppm is mass ppm.)

According to the second aspect of the present invention, the first aspect
In the invention, the copolymer emulsion (a) is a polymerizable unsaturated monomer (d) 27 to 7 having an ion-forming group.
0% by mass, 0 to 4% by mass of the polymerizable unsaturated monomer (e) having a hydrolyzable silyl group, and 16 to 70% by mass of the other polymerizable unsaturated monomer (f) are copolymerized. There is provided a resin composition for inkjet recording, which is the acrylic copolymer emulsion (g) obtained as described above.

Furthermore, according to the third invention of the present invention, there is provided a resin composition for ink jet recording according to the first invention, wherein the ionic property of the copolymer emulsion (a) is cationic. Provided.

According to the fourth aspect of the present invention, the second aspect
In the invention of, the acrylic copolymer emulsion (g)
Is a water-based resin composition obtained by adding water to a resin solution obtained by solution polymerization to form an emulsion, and then removing a polymerization solvent, to provide an ink jet recording resin composition. It

Furthermore, according to the fifth aspect of the present invention, in the second aspect, the acrylic copolymer emulsion (g) is polymerized in the presence of the radically polymerizable surfactant (h). A characteristic ink-jet recording resin composition is provided.

According to the sixth aspect of the present invention, the fifth aspect
In the invention, there is provided a resin composition for inkjet recording, wherein the radically polymerizable surfactant (h) is cationic.

According to the seventh invention of the present invention, in the third invention, the copolymer emulsion (a) contains the polyvinyl alcohol (i) in an amount of 0 to 30% by mass based on the total amount of the composition.
There is provided a resin composition for inkjet recording characterized by containing the same.

According to an eighth aspect of the present invention, the first aspect
In the invention, the inorganic fine particles (c) have an average particle size of 3 to 3
There is provided a resin composition for inkjet recording, which is silica having a particle size of 00 nm.

On the other hand, according to the ninth aspect of the present invention, the first aspect
A recording sheet having at least one recording layer formed of the resin composition for inkjet recording according to any one of items 1 to 8 is provided.

The present invention provides the ink jet recording resin composition for forming a recording layer on a substrate as described above,
The resin composition for ink jet recording comprises a specific ratio of the copolymer emulsion (a) and the inorganic fine particles (b), and the free emulsifier (c) content (CX) in the copolymer emulsion (a). Relates to a resin composition for inkjet recording characterized by satisfying a specific relational expression, and preferable embodiments thereof include the following. (1) In the second invention, the resin composition for inkjet recording is characterized in that the acrylic copolymer emulsion (g) has a glass transition temperature of -40 to 120 ° C. (2) In the fifth invention, the amount of the radically polymerizable surfactant (h) used is 0.001 to 30% by mass based on the total mass of the polymerizable unsaturated monomer (d to f). A resin composition for inkjet recording, comprising: (3) A recording sheet according to the ninth invention, which has at least one recording layer on a substrate.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
In the present specification, “acrylic” polymerizable monomer and “methacrylic” polymerizable monomer are collectively referred to as “(meth) acrylic” polymerizable monomer and the like. 1. Copolymer Emulsion (a) The copolymer emulsion (a) used in the ink jet recording resin composition of the present invention includes an acrylic copolymer emulsion (g), a urethane copolymer emulsion, and an ethylene-vinyl acetate copolymer. Conventionally known ones such as a combined emulsion, a vinyl acetate copolymer emulsion and a styrene-butadiene copolymer emulsion can be used.
Among these, the acrylic copolymer emulsion (g), the urethane copolymer emulsion, and the ethylene-vinyl acetate copolymer emulsion are preferably used.

In the present invention, in the copolymer emulsion (a), the content (AX) of the contained copolymer component and the content (CX) of the free emulsifier (c) are represented by the relational expression (1). The most important feature is that 0 wppm ≦ CX / AX <10000 wppm (Formula 1) (where CX is the content of the free emulsifier (c) in the copolymer emulsion (a), and AX is the copolymer weight of the copolymer emulsion (a). (The amount of combined components is shown, and wppm is mass ppm.)

The above acrylic copolymer emulsion (g) comprises a polymerizable unsaturated monomer (d) having an ion-forming group and a polymerizable unsaturated monomer (e) having a hydrolyzable silyl group. And other polymerizable unsaturated monomer (f) are copolymerized to obtain an acrylic copolymer.

(1) Polymerizable unsaturated monomer (d) having an ion forming group In the present invention, the polymerizable unsaturated monomer (d) having an ion forming group is one of the components for copolymerization. Used as. 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.

Therefore, examples of the monomer having a cation-forming group include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminopropyl (meth) acrylate and dimethyl. Examples thereof include aminoethyl (meth) acrylamide, (meth) acryloyloxyethyltrimethylammonium chloride and (meth) acryloyloxyethyltrimethylammonium sulfate. These cation-forming group-containing monomers can be used alone or in combination of two or more.

Examples of the monomer having an anion-forming group include carboxyethyl (meth) acrylate, carboxypropyl (meth) acrylate, vinylcarboxylic acid [(meth) acrylic acid, ethacrylic acid, crotonic acid, Sorbic acid, maleic acid, itaconic acid, cinnamic acid, etc.], vinyl sulfonic acid [vinyl sulfonic acid, allyl sulfonic acid, vinyl tolueneene sulfonic acid, styrene sulfonic acid, etc.], (meth) acrylic sulfonic acid [(meth) acrylic Acid sulfoethyl, (meth) acrylic acid sulfopropyl and the like], (meth) acrylamide sulfonic acid [2-acrylamido-2-methylpropane sulfonic acid and the like] and the like. These monomers having an anion-forming group can be used alone or in combination of two or more.

It is preferable to contain a monomer having a cation-forming group in terms of ink fixability of a printed image in ink jet recording and improvement of environmental gas resistance. In particular,
It is preferable to use a polymerizable unsaturated monomer having an ion-forming group in a composition such that the ionicity of the copolymer emulsion (a) becomes cationic.

The content of the polymerizable unsaturated monomer (d) having an ion-forming group is 27 to 7 based on the total amount of the copolymer.
It is 0% by mass, preferably 30 to 60% by mass, and more preferably 33 to 55% by mass. When the content of the polymerizable unsaturated monomer (d) is less than 27% by mass, the affinity with the ink is lowered and the effect of improving the environmental gas resistance is reduced. 7
If it exceeds 0% by mass, water resistance may be poor or stickiness may occur.

(2) Polymerizable unsaturated monomer having a hydrolyzable silyl group (e) In the present invention, the polymerizable unsaturated monomer having a hydrolyzable silyl group (e) is used as a component for copolymerization. Used as one of. Examples of the polymerizable unsaturated monomer (e) having a hydrolyzable silyl group include monomers containing a hydrolyzable and condensable group such as a silyl group [vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane. , Vinylmethoxydimethylsilane, vinylethoxydimethylsilane, vinylisobutoxydimethylsilane, vinyldimethoxymethylsilane, vinyldiethoxymethylsilane, vinyltris (β-methoxyethoxy) silane, vinyldiphenylethoxysilane, vinyltriphenoxysilane, γ- ( Vinylphenylaminopropyl) trimethoxysilane, γ- (vinylbenzylaminopropyl) trimethoxysilane, γ- (vinylphenylaminopropyl) triethoxysilane, γ- (vinylbenzylaminopropyl) triethoxysilane, Divinyldimethoxysilane, divinyldiethoxysilane, divinyldi (β-methoxyethoxy) silane, vinyldiacetoxymethylsilane, vinyltriacetoxysilane, vinylbis (dimethylamino) methylsilane, vinylmethyldichlorosilane, vinyldimethylchlorosilane, vinyltrichlorosilane, vinyl Methylphenylchlorosilane, allyltriethoxysilane, 3-allylaminopropyltrimethoxysilane, allyldiacetoxymethylsilane, allyltriacetoxysilane, allylbis (dimethylamino) methylsilane, allylmethyldichlorosilane, allyldimethylchlorosilane, allyltrichlorosilane, meta Rylphenyldichlorosilane, β- (meth) acryloxyethyltrimethoxysilane, β- (meth) acryloxy Tilttriethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropylmethyl Dichlorosilane, γ- (meth)
Acryloxypropyl tris (β-methoxyethoxy)
Silane, etc.] and the like. Those having an alkoxysilyl group (C _1-4 alkoxysilyl group such as methoxysilyl group and ethoxysilyl group) are preferable.

The content of the polymerizable unsaturated monomer (e) having a hydrolyzable silyl group is 0 to the total amount of the copolymer.
It is 4% by mass, preferably 0.2 to 2.5% by mass, more preferably 0.5 to 1.5% by mass. When the content (copolymerization amount) of the polymerizable unsaturated monomer (e) is higher, the coating strength and water resistance are improved by crosslinking, but when it exceeds 4% by mass, the content of the inorganic fine particle component is The interaction reduces the stability of the recording layer resin composition as a coating liquid.

(3) Other polymerizable unsaturated monomer (f) In the present invention, the other polymerizable unsaturated monomer (f) is
It is one of the components for copolymerization to form the acrylic copolymer emulsion (g), and is a polymerizable unsaturated monomer (d) having an ion-forming group and a polymerizable unsaturated monomer having a hydrolyzable silyl group. It occupies the balance with the saturated monomer (e).

Other polymerizable unsaturated monomers (f) include
Two or more kinds of (meth) acrylic polymerizable unsaturated monomers and other polymerizable unsaturated monomers can be used in combination. Examples of the (meth) acrylic polymerizable unsaturated monomer include (meth) acrylate, (meth) acrylamides, and (meth) acrylonitrile.

Examples of the (meth) acrylate include alkyl (meth) acrylates [eg methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate], isopropyl (meth) acrylate, butyl (meth) acrylate. , Isobutyl (meth) acrylate, t-butyl (meth) acrylate,
Hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
Lauryl (meth) acrylate, _{C 1-1 8} alkyl, such as (meth) acrylate, etc.], cycloalkyl (meth) acrylates [e.g., cyclohexyl (meth) acrylate, etc.], aryl (meth) acrylates [e.g., phenyl (meth) Acrylate etc.], aralkyl (meth) acrylate [eg benzyl (meth) acrylate etc.], hydroxyalkyl (meth) acrylate [eg hydroxy-C such as 2-hydroxyethyl, 2-hydroxypropyl (meth) acrylate etc.
_2-4 alkyl (meth) acrylate, etc.], glycidyl (meth) acrylate, dialkylamino-alkyl (meth) acrylate [eg, 2- (dimethylamino) ethyl (meth) acrylate, 2- (diethylamino) ethyl (meth) acrylate. etc. di _{C 1-4 alkylamino--C 2-4} alkyl, such as (meth) acrylate, etc.].

Examples of (meth) acrylamides include:
(Meth) acrylamide, hydroxyalkyl (meth)
Acrylamide, [eg, N-hydroxy-C _1-4 alkyl (meth) acrylamide such as N-methylol (meth) acrylamide], alkoxyalkyl (meth) acrylamide, [eg N-such as N-methoxymethyl (meth) acrylamide, etc. C _1-4 alkoxy-C _1-4 alkyl (meth) acrylamide and the like], diacetoxy (meth) acrylamide and the like.

Preferred (meth) acrylic monomers include, for example, methacrylate [eg C _1-18 alkyl (meth) acrylate, hydroxy-C _2-4 alkyl (meth) acrylate, glycidyl (meth) acrylate, (Ci- ₄ alkylamino- _C2-4 alkyl (meth) acrylate], and (meth) acrylamides. More preferably (meth) acrylic polymerizable unsaturated _{monomer, C 2-10} alkyl _{acrylates, C 1-6} alkyl methacrylate, hydroxy _{-C 2 -3} alkyl (meth) acrylate, glycidyl (meth) Akurureto, and di _{C 1 -3} alkyl amino _{-C 2-3} alkyl (meth) acrylate.

Other examples of the polymerizable unsaturated monomer include radically polymerizable light stabilizers and the like. Examples thereof include hindered amines such as 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate. A system light stabilizer can be used. Examples of commercially available products include Adegastub LA-82 and LA available from Asahi Denka Co., Ltd.
-87 etc. are mentioned.

As the other polymerizable unsaturated monomer,
Radical-polymerizable UV absorbers are also included, and examples of the radical-polymerizable UV absorbers include benzophenone-based UV absorbers such as 2-hydroxy-4-acryloxybenzophenone and 2- (2'-hydroxy-5'-. A benzotriazole-based ultraviolet absorber such as methacryloxyethylphenyl) -2H-benzotriazole can be used. Examples of commercially available products include RUVA-93 manufactured by Otsuka Chemical Co., Ltd. and CG manufactured by Ciba-Geigy Japan.
L-104 etc. are mentioned.

Further, aromatic vinyls, vinyl esters, halogen-containing vinyls, vinyl ethers (eg vinyl ethyl ether etc.), vinyl ketones (eg methyl vinyl ketone etc.) and vinyl heterocyclic compounds (eg N-). Vinylpyrrolidone, N-vinyl compounds such as N-vinylimidazole, N-vinylpyridine, etc.), olefinic monomers (eg, ethylene, propylene, etc.), allyl compounds (eg, allyl esters such as allyl acetate), etc. Can be mentioned. This polymerizable unsaturated monomer may be used alone or in combination of two or more kinds.

The content of the other polymerizable unsaturated monomer (f) occupies the rest of the polymerizable unsaturated monomers (d) and (e),
The amount is 16 to 70% by mass, preferably 36 to 68% by mass, and more preferably 40 to 65% by mass, based on the total amount of the copolymer.

(4) Acrylic Copolymer Emulsion (g) The acrylic copolymer emulsion (g) obtained from the above-mentioned polymerizable unsaturated monomers (d) to (f) is usually a hard monomer [eg ( A monomer component forming a homopolymer having a glass transition temperature of about 30 to 140 ° C. such as methyl (meth) acrylate and styrene], and a soft monomer [eg, a glass transition temperature of C _2-10 alkyl acrylate- The glass transition temperature when used in combination with a monomer component that forms a homopolymer at about 85 ° C to 30 ° C is often set, and it is -40 to 120 ° C, preferably -20 to 110 ° C, and further. Is 0 to 100 ° C.

As described above, when a hard monomer and a soft monomer are usually used as the polymerizable unsaturated monomer,
The mixing ratio is not particularly limited, but for example, 10 to 90% by mass of the hard monomer (for example, 15 to 85% by mass, preferably 20 to 80% by mass, more preferably 25 to 7% by mass).
5% by weight, especially 30 to 70% by weight), soft monomer 1
It can be 0 to 90% by mass (for example, 15 to 85% by mass, preferably 20 to 80% by mass, more preferably 25 to 75% by mass, and particularly 30 to 70% by mass).

In the present invention, the copolymer emulsion (a) is preferably a cationic resin composition containing the polyvinyl alcohol (i). By containing the polyvinyl alcohol (i), there is an advantage that affinity with the ink is increased. As the polyvinyl alcohol (i) that can be used in the present invention, conventionally known polyvinyl alcohol can be used. To the polyvinyl alcohol (i), a water resistance improver composed of a cross-linking agent or the like, an ink fixing agent composed of a cationic polymer or the like may be added. The amount of polyvinyl alcohol (i) contained in the copolymer emulsion (a) is 0 to 30% by mass, preferably 1 to 20% by mass, and further 2 to 10% by mass.

Further, as described above, in the present invention, the copolymer emulsion (a) contains the copolymer component amount (AX) and the free emulsifier (c) content (C).
The greatest feature is that X) and X satisfy the relational expression of (Equation 1). 0 wppm ≦ CX / AX <10000 wppm (Formula 1) (where CX is the content of the free emulsifier (c) in the copolymer emulsion (a), and AX is the copolymer weight of the copolymer emulsion (a). (The amount of combined components is shown, and wppm is mass ppm.)

In the copolymer emulsion (a), the content (CX) ratio (CX / AX) of the free emulsifier (c) to the contained copolymer component amount (AX) is 100.
When it is less than 00 wppm, that is, when it is less than 1% by mass, it is possible to form a recording layer having good environmental gas resistance such as ozone resistance.

In the present invention, the copolymer emulsion (a) used as the binder resin can be obtained by copolymerization using various known polymerization methods such as emulsion polymerization. A method is preferably used in which the solution polymerization is performed, water is added to the obtained resin solution to form an emulsion, and then the solvent used for the solution polymerization is removed to obtain an aqueous resin composition. That is, the above-mentioned respective copolymerization components are mixed and copolymerized in the presence of a suitable organic solvent, and this polymer is treated with an alkali (for example, alkylamine such as triethylamine, cyclic amine such as morpholine, triethanolamine or the like). Alkanolamine, pyridine, ammonia, etc.) and acids [eg, inorganic acids (eg, hydrochloric acid, sulfuric acid, etc.), organic acids (eg, acetic acid,
Carboxylic acid such as propionic acid, sulfonic acid, etc.)] or the like. The polymerization operation is
It may be a batch type or a continuous type.

Examples of the organic solvent used in the solution polymerization include alcohols (eg ethanol, isopropanol, n-butanol etc.) and aromatic hydrocarbons (eg
Benzene, toluene, xylene etc.), aliphatic hydrocarbons (eg pentane, hexane, heptane etc.), alicyclic hydrocarbons (eg cyclohexane etc.), esters (eg ethyl acetate, n-butyl acetate etc.), ketones (For example, acetone, methyl ethyl ketone, etc.), ether (for example, diethyl ether, dioxane, tetrahydrofuran, etc.), etc. can be used. You may use these organic solvents individually or in combination of 2 or more types. The organic solvent is usually an alcohol such as isopropanol, an aromatic hydrocarbon such as toluene,
Ketones such as methyl ethyl ketone are used.

The amount of the organic solvent used is not particularly limited, and for example, the amount of the organic solvent with respect to the total amount of the polymerizable unsaturated monomer is (0.1 / 1 to 5/1) in mass ratio, and preferably (0 .5
It can be selected from the range of about / 1 to 2/1).

The acrylic copolymer emulsion (g) can be obtained by copolymerization using a polymerization method such as emulsion polymerization as described above, in which case a radically polymerizable surfactant is used. Polymerization is desirable in the presence of (h). Radical polymerizable surfactant (h)
In the copolymer emulsion (a), the content (CX) of the free emulsifier (c) relative to the content (AX) of the copolymer component contained (CX) in the copolymer emulsion (a).
X / AX) can be less than 10000 wppm, and a recording layer having good environmental gas resistance such as ozone resistance can be formed. The radically polymerizable surfactant has the same function as a general surfactant during polymerization, and after polymerization, it is copolymerized or grafted to a polymer. As a result, there is essentially no free emulsifier (or surfactant) in the emulsion. The content (CX) of the free emulsifier (c) can be measured using gas chromatography.

As the radically polymerizable surfactant (h), for example, an acrylic or maleic acid-based reactive surfactant or a reactive (polymerizable) emulsifier can be used. As examples of commercially available products, trade names “Adekaria Soap NE-10 and NE-2” available from Asahi Denka Kogyo Co., Ltd.
0, SE-10N, SE-11, DQ-80 "and trade name" Light Ester DQ75 "manufactured by Kyoeisha Chemical Co., Ltd.
And nonionic, anionic, and cationic ones. Cationic ones are preferably used. The amount of the radically polymerizable surfactant (h) used is not particularly limited, and may be, for example, 0. 0 based on the total mass of the polymerizable unsaturated monomer.
001 to 30% by mass, preferably 0.01 to 20% by mass
(For example, 0.1 to 10% by mass) can be selected from the range.

In solution polymerization, the polymerization may be initiated by irradiation with electron beams or ultraviolet rays, but the polymerization is often initiated using a polymerization initiator. Examples of the polymerization initiator include 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 (eg, potassium persulfate, sodium persulfate, persulfates such as ammonium persulfate, hydrogen peroxide), organic peroxides (eg, benzoyl peroxide) ,
Di-t-butyl peroxide, cumene hydroxyperoxide, di (2-ethoxyethyl) peroxydicarbonate] and redox catalyst [eg sulfite or bisulfite (eg alkali metal salt, ammonium salt etc.), L- A catalyst system comprising a combination of a reducing agent such as ascorbic acid and erythorbic acid and an oxidizing agent such as persulfate (eg, alkali metal salt, ammonium salt) and peroxide] can be exemplified. The polymerization initiators can be used alone or in combination of two or more kinds.

The amount of the polymerization initiator used is, for example, 0.001 to 20% by mass based on the total mass of the polymerizable unsaturated monomer,
Preferably 0.01 to 10% by mass (eg 0.1 to 1
It can be selected from the range of about 0% by mass.

The reaction temperature in solution polymerization is, for example, 5
The temperature is 0 to 150 ° C, preferably about 70 to 130 ° C.
The reaction time is, for example, 1 to 10 hours, preferably 2 to 7 hours. The end point of the polymerization is the double bond absorption (1648c) in the infrared absorption spectrum.
It can be confirmed by the disappearance of m ⁻¹ ), or reduction of unreacted monomers using gas chromatography.

When the polymer contains a cation-forming group such as an amino group or an imide group, the use of an acid improves the hydrophilicity and allows the polymer to be easily dissolved or emulsified. Examples of such acids include inorganic acids (eg, hydrochloric acid, phosphoric acid, sulfuric acid, nitric acid, etc.), organic acids [eg, saturated aliphatic monocarboxylic acids such as formic acid, acetic acid, propionic acid, oxalic acid, adipic acid, etc. Saturated aliphatic polycarboxylic acid such as, unsaturated aliphatic polycarboxylic acid such as (meth) acrylic acid, unsaturated aliphatic polycarboxylic acid such as maleic acid and itaconic acid, aliphatic oxycarboxylic acid such as lactic acid and citric acid Etc.] can be exemplified.

When the polymer has an anion-forming group such as a carboxyl group, a base can be used to easily dissolve or emulsify the polymer. Such bases include, for example, organic bases (eg, alkylamines such as triethylamine, cyclic amines such as morpholine, alkanolamines such as triethanolamine, pyridine), inorganic bases (eg, ammonia, alkali metal hydroxides). Etc.) etc. are included.

The amount of the acid and the base used is, for example, based on the total molar ratio of the anion-forming groups, base / anion-forming group = 0.3 / 1 to 1.5 / 1 (molar ratio), and cation-forming group. Acid / cation-forming group = based on the total molar ratio of the functional groups =
It can be selected from the range of about 0.3 / 1 to 1.5 / 1 (molar ratio).

When polymerizing such an acrylic copolymer emulsion (g), for example, the acrylic copolymer emulsion (g) and the inorganic fine particles (b) which constitute the coating liquid for forming the ink jet recording composition. Polymerization may be carried out in the presence of a part or all of the inorganic fine particles (b) to be added to the coating liquid, from the viewpoint of improving the mixing property of (1). The content of the inorganic fine particles (b) blended in the polymerization solution is 3 to 80 parts by mass, preferably 5 to 30 parts by mass with respect to 100 parts by mass as the total mass of the polymerizable unsaturated monomer contained therein. .

The emulsification of the polymer obtained by solution polymerization is
It can be carried out in the presence or absence of an organic solvent. In the presence of an organic solvent, when dissolving or emulsifying and dispersing the polymer,
As the organic solvent, a water-soluble organic solvent (for example, alcohol such as isopropanol) is often used. When the polymer is emulsified in the presence of an organic solvent, the organic solvent may be removed by evaporation after the emulsification, and the obtained emulsion may contain the organic solvent. In addition,
When removing the organic solvent before emulsifying the polymer, an organic solvent having a low boiling point (for example, a ketone such as methyl ethyl ketone) is often used.

When the polymer obtained by solution polymerization is emulsified in the presence of an organic solvent, additives (for example, an emulsifier, a pH adjusting agent, an acid, etc.) are added to the organic solution containing the polymer, and then water is added. Can be added to emulsify. In this case, it is preferable to add water gradually by dropping or the like. The temperature at the time of emulsification is preferably low, for example, 5 to 70 ° C,
Preferably, it can be selected from the range of about 10 to 50 ° C.
In the present invention, the addition of an emulsifier requires caution because it may impair the characteristics of the present invention.

The removal of the organic solvent after addition of water and emulsification is often carried out, for example, at a temperature of about 5 to 80 ° C. under normal pressure or reduced pressure (for example, about 0.01 to 100 kPa).

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

The average particle size of the polymer particles in the acrylic copolymer emulsion (g) thus obtained is in a range that does not impair the dispersion stability, adhesion, etc., for example, 0.01 to 1 μm, preferably 0. 0.01-0.5μ
m, more preferably 0.02 to 0.3 μm, and even more preferably 0.03 to 0.2 μm.

In the acrylic copolymer emulsion (g) according to the present invention, if necessary, other stabilizers such as a lubricant, an antioxidant, an ultraviolet absorber and a heat stabilizer,
You may add various well-known additives, such as a radical scavenger, a quencher, an antistatic agent, a plasticizer, a thickener, and a defoaming agent.

2. Inorganic particles (b) Examples of the inorganic particles (b) used in the recording resin composition of the present invention include alumina, silica, calcium carbonate,
Examples thereof include aluminum hydroxide and calcium silicate.
Silica is preferable, and colloidal silica is particularly preferable. Specifically, it is a water dispersion type silica sol or an organo silica sol. A small particle size is preferable for the gloss and transparency of the ink receiving layer. For example, 3 ~
It is 300 nm or less, preferably 5 to 50 nm or less.
The shape of the inorganic particles may be spherical, flat, columnar, or beaded.

3. Ink jet recording resin composition A binder resin comprising the copolymer emulsion (a) such as the acrylic copolymer emulsion (g) thus obtained and inorganic fine particles (b) are mixed to form a recording layer. An ink jet recording resin composition used for the above is prepared. As a mixing method, a conventionally known method can be used. In addition, a high pressure homogenizer or the like is used to disperse inorganic particles such as silica particles having a large particle size (1 μm or more) such as dry silica or wet silica in water in the presence of the acrylic copolymer (g). The inorganic fine particles (b) of the present invention may be pulverized and mixed so as to fall within the particle size range. As such a high-pressure homogenizer, for example,
Examples include a high-pressure jet flow emulsifier manufactured by Japan BEE Co., Ltd., a jet stream mixer manufactured by Mitamura Riken Kogyo Co., Ltd., and a nanomanizer manufactured by Nanomanizer Co., Ltd.

The mixing ratio is 3 to 60% by mass of the copolymer emulsion (a) and 97 to 4 of the inorganic fine particles (b).
It is 0 mass%. Preferably, the copolymer emulsion (a) is 5 to 30 mass% and the inorganic fine particles (b) are 95 to 7%.
It is 0 mass%. When the content of the inorganic fine particles (b) exceeds 97% by mass, the film-forming property tends to decrease, while when it is less than 40% by mass, the quick drying property and the ink absorption property decrease.

The ink-jet recording resin composition used for forming the recording layer contains a conventional ink fixing agent, cross-linking agent, light resistance stabilizer, ultraviolet absorber, anti-blocking agent, and film-forming auxiliary as long as the characteristics are not lost. Additives for improving the ink jet recording property, the storage stability of the recording material, the characteristics of the coating liquid, and the like may be further added as necessary.

4. Recording Layer The recording layer is usually formed by using the above ink jet recording resin composition. The recording layer may optionally contain other components, for example, a polymer having no crosslinkable group or an aqueous emulsion containing the polymer (for example, ethylene-
Vinyl acetate copolymer emulsion, vinyl acetate emulsion, etc.) may be contained. Also, in the recording layer,
A powder or granular material (such as a pigment) may be contained. Here, as the granular material, for example, inorganic granular material (white carbon, particulate calcium silicate, zeolite, magnesium aminosilicate, calcined diatomaceous earth, particulate magnesium carbonate, particulate alumina, talc, kaolin, deramikarin, clay, Mineral powder such as heavy calcium carbonate, light calcium carbonate, magnesium carbonate, titanium dioxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, magnesium silicate, calcium sulfate, sericite, bentonite, and smetite), organic Examples thereof include powder particles (crosslinked or non-crosslinked organic fine particles such as polystyrene resin, urea resin, melamine resin and benzoguanamine resin, organic powder particles such as fine hollow particles). These powders and granules may be used alone or in combination of two or more kinds, appropriately selected.

When the powder or granule is used, a hydrophilic polymer such as a saponified vinyl acetate copolymer can be used as the binder resin. The ratio of the powder and granules to the binder resin is about 0.1 to 80 parts by mass, and preferably about 0.2 to 50 mass parts with respect to 100 parts by mass of the binder resin.

5. Substrate In the present invention, the substrate on which the recording layer is formed may be opaque, semi-transparent or transparent depending on the application, and when used in an overhead projector (OHP) or the like, the substrate is usually It is transparent. The material of the substrate is not particularly limited, and examples of usable substrates include paper, coated paper, non-woven fabric, plastic film, and synthetic paper.

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, poly (meth) acrylic. Acid ester, polystyrene, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, cellulose derivatives such as cellulose acetate,
Polyester (polyalkylene terephthalate such as polyethylene terephthalate and polybutylene terephthalate, polyalkylene arylate such as polyethylene naphthalate and polybutylene naphthalate), polycarbonate, polyamide (polyamide 6, polyamide 6)
/ 6, polyamide 6/10, polyamide 6/12, etc.), polyester amides, polyethers, polyimides, polyimide amides, polyether esters, and the like. Further, using copolymers, blends, and crosslinked products of these Good.

Polyolefins (especially polypropylene), polyesters (especially polyethylene terephthalate), polyamides, etc. are usually used as the polymers constituting these plastic films or synthetic papers, and in particular mechanical strength, workability, cost, etc. From the viewpoint of, polyester (particularly polyethylene terephthalate) is preferable. 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 base material can be selected according to the application and is usually 5 to 500 μm, preferably 10 to 300 μm. The base material may have a sizing agent, an antioxidant, an ultraviolet absorber, a heat stabilizer, or an internal or surface thereof, if necessary.
Conventional additives such as lubricants and pigments may be used. In addition, surface treatment such as corona discharge treatment or undercoat treatment may be performed in order to improve the adhesiveness to the recording layer.

6. Method for Producing Recording Sheet The recording sheet of the present invention can be produced by forming a recording layer on at least one surface of the above-mentioned substrate with a coating liquid comprising the resin composition for inkjet recording of the present invention. . That is, the recording layer can be formed by applying the prepared coating liquid to the base material. The coating solution is 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, etc. Cast or coated on. The recording layer can be formed by applying a coating liquid containing the above components to at least one surface of the substrate and drying. Further, if necessary, after coating the coating liquid, it may be heated at an appropriate temperature selected from the range of about 50 to 150 ° C. to form a crosslinked ink absorbing layer. If necessary, a porous layer, an antiblocking layer, a slipping layer, an antistatic layer or the like may be formed on the recording layer. Further, if necessary, the surface of the recording layer may be smoothed by using a super calendar or the like.

The thickness of the recording layer formed by the above ink jet recording resin composition can be selected according to the application,
For example, it is about 1 to 50 μm, preferably about 3 to 30 μm, and more preferably about 5 to 20 μm.

A preferable layer constitution of the recording sheet is a layer constitution in which at least one layer of an ink absorbing layer made of inorganic fine particles is formed on a substrate, and the recording layer is further formed thereon. As the inorganic fine particles forming the ink absorbing layer, conventionally known dry silica fine particles and / or wet silica fine particles can be preferably used. Further, as the binder resin, a conventionally known one such as polyvinyl alcohol can be used.

[0077]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited by these examples. Unless otherwise specified, the mass% of the copolymer emulsion (g) and the inorganic fine particles (b).
Is the solid content, and hereinafter, the number of parts is the number of parts by mass, and% is% by mass.
And The following performance items were evaluated for the ink jet recording resin compositions and recording sheets obtained in Examples and Comparative Examples.

(Gas resistance 1: Ozone resistance 1) Yellow:
A color pattern of Y, magenta: M, cyan: C, black: B is printed on a recording sheet, and the gas concentration is 5 mg / L,
The sample was stored in an ozone exposure tank at a temperature of 40 ° C. and a humidity of 85% RH for 6 hours, and the color densities before and after the storage were measured with a Macbeth color densitometer. When the average color density retention rate of the cyan print portion with a large change in color density is 85% or more, it is ⊚, 70 to 85% is ∘, and 60 to 70%.
Was evaluated as Δ, and less than 60% was evaluated as x.

(Gas resistance 2: ozone resistance 2) Yellow:
A color pattern of Y, magenta: M, cyan: C, black: B is printed on a recording sheet, and the gas concentration is 5 mg / L,
Stored in an ozone exposure tank at a temperature of 40 ° C without humidification for 6 hours,
The color density before and after storage was measured with a Macbeth color densitometer. The average color density retention rate of the cyan print area where the color density changes greatly is 85.
% Or more for ◎, 70 to 85% for ○, 60 to 70% for △, 6
Evaluation was made with x being less than 0%.

(Ink Drying Property) Solid images of cyan, magenta, yellow, black, and red, green, and blue, which are mixed colors of these, are printed by using an Epson printer (Epson PM800C), and after 30 seconds, the printed portion is printed. Put PPC copy paper and load (500g / cm
^{After 2} ) was applied for 10 seconds, the PPC paper was peeled off, and the degree of ink transfer to the copy paper was visually judged according to the following criteria. ◯: No ink transfer was observed on the copy paper. Δ: Ink transfer is slightly recognized. X: Ink transfer is remarkable.

(Print Quality) Using the above printer, ISO
A standard image was printed and visually judged according to the following criteria. ◯: No defective image quality such as bleeding or unevenness is observed. B: Image quality defects such as slight bleeding and unevenness are recognized. X: Image quality defects such as bleeding and unevenness are remarkable and a clear image cannot be obtained.

[Synthesis Example 1] Acrylic copolymer (g-1)
(Cationic) In a 2 liter reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, nitrogen introducing tube and thermometer, 470 parts of isopropyl alcohol (hereinafter abbreviated as "IPA") and azoisobutyro 1.23 parts of nitrile (hereinafter abbreviated as "AIBN") was added, stirred and dissolved, and heated to 80 ° C. As a copolymerization component e, 3-methacryloxypropyltrimethoxysilane (manufactured by Nippon Unicar Co., Ltd., A-174) 3.21
Part, 118.63 parts of methyl methacrylate (hereinafter abbreviated as "MMA") as a copolymerization component f, and a copolymerization component d
As diethylaminoethyl methacrylate 105.
81 parts, polyethylene glycol methacrylate (manufactured by NOF CORPORATION, Bremmer PE-200) 60.92
And 30.06 parts of acrylic acid (hereinafter abbreviated as “AA”) were mixed and added dropwise into the flask over about 4 hours. After completion of dropping, 0.25 part of AIBN and IPA25 as an additional catalyst
Then, the solution was added dropwise, and the reaction was further continued for 2 hours to complete the polymerization. After completion of the polymerization, acetic acid 1
After 6 parts were added to the flask and 705 parts of water was added dropwise over about 2 hours, the solvent was evaporated by a rotary evaporator to obtain an acrylic copolymer: g-1 (cationic). The content ratio (CX / AX) of the free emulsifier (c) to the acrylic copolymer (g-1) component is
It is 0 because no surfactant or emulsifier is used.

[Synthesis Example 2] Acrylic copolymer (g-2)
Synthesis (anionic) In a 2 liter reaction vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a nitrogen introduction tube and a thermometer, 175 parts of IPA was added, and 0.62 parts of AIBN was added to dissolve the mixture, Warmed to ° C. As a copolymerization component, MMA69
Part, n-butyl acrylate (hereinafter abbreviated as "BA") 4
4 parts, 3-methacryloxypropyltrimethoxysilane (manufactured by Nippon Unicar Co., Ltd., A-174) 6 parts, AA51
The parts were mixed and added dropwise to the reaction vessel using a dropping funnel over about 4 hours. After dropping, AIBN is added as an additional catalyst.
0.25 part was dissolved in 25 parts of IPA and added dropwise to the reaction vessel, and the reaction was further held for 2 hours. After completion of the polymerization, while continuing stirring, 7.2 parts of 25% (w / v) ammonia water was added to the reaction container, and 705 parts of water was added dropwise to the reaction container over about 2 hours to form an emulsion. After emulsification, IPA was evaporated using a rotary evaporator to obtain the desired hydrolyzable silyl group-containing anionic acrylate resin (g-2). Content ratio of free emulsifier (c) to acrylate resin (g-2) (CX / AX)
Is 0.

[Synthesis Example 3] Acrylic copolymer (g-3)
Synthesis (cationic) In a 2 liter reaction vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a nitrogen introducing tube and a thermometer, ion-exchanged water 31
8 parts was added, and the mixture was stirred and heated to 75 ° C. 0.7 parts of 3-methacryloxypropyltrimethoxysilane (A-174 manufactured by Nippon Unicar Co., Ltd.), 15 parts of MMA, BA
15 parts, diethylaminoethyl methacrylate 33 parts,
20 parts of polyethylene glycol methacrylate (Nippon Yushi Co., Ltd., Bremmer PE-200), AA10
Parts, radical-polymerizable surfactant dimethylaminoethyl methacrylate quaternary product (manufactured by Kyoeisha Chemical Co., Ltd., product name Light Ester DQ75) 8 parts and ion-exchanged water 60
An emulsion obtained by emulsifying g in advance and an aqueous catalyst solution (aqueous solution of 0.5 g of 2,2-azobis (2-amidinopropane) dihydrochloride and 16.5 g of ion-exchanged water) are added dropwise to the reaction vessel over 2 hours. did. After reacting for an additional 1 hour, the mixture was cooled to room temperature to obtain the desired aqueous emulsion (g-3). The content ratio (CX / AX) of the free (unreacted) radically polymerizable surfactant contained in the product (g-3) was 200.
It was 0 wppm or less.

[Synthesis Example 4] Acrylic copolymer (g-4)
Synthesis (anionic) In a 2 liter reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, nitrogen introducing tube and thermometer, ion-exchanged water 31
8 parts was added, and the mixture was stirred and heated to 75 ° C. MMA40.
4 parts, BA 25.8 parts, AA 29.9 parts, 3-methacryloxypropyltrimethoxysilane (manufactured by Nippon Unicar Co., Ltd., A-174) 0.7 parts, radically polymerizable surfactant (reactive emulsifier) ( Asahi Denka Kogyo Co., Ltd., 8 parts of trade name ADEKA RIASOAP SE-11) and 60 g of ion-exchanged water are emulsified in advance, and an aqueous catalyst solution (0.5 g of potassium persulfate and 16.5 g of ion-exchanged water). ) And were added dropwise to the reaction vessel over 2 hours. 1 more
After reacting for a time, the mixture was cooled to room temperature to obtain the desired aqueous emulsion (g-4). Content ratio of free radical-polymerizable surfactant contained in product (g-4) (CX / A
X) was 2000 wppm or less.

[Synthesis Example 5] Acrylic copolymer (g-5)
In a 2 liter reaction vessel equipped with a synthetic stirrer, a reflux condenser, a dropping funnel, a nitrogen introduction tube and a thermometer, ion-exchanged water 31
8 parts was added, and the mixture was stirred and heated to 75 ° C. MMA73
Part, BA 24 parts, 3-methacryloxypropyltrimethoxysilane (manufactured by Nippon Unicar Co., Ltd., A-174) 0.
7 parts, a surfactant (manufactured by Nippon Emulsifier Co., Ltd., trade name Newcol 707SF), and an emulsion liquid in which 60 g of ion-exchanged water was emulsified in advance, and an aqueous catalyst solution (potassium persulfate 0.5
g and an aqueous solution of 16.5 g of ion-exchanged water) were added dropwise to the reaction vessel over 2 hours. After reacting for another hour,
It cooled to room temperature and obtained the target aqueous emulsion (g-5). The solid content of this resin composition was 40%. The content ratio (CX / AX) of the free surfactant (emulsifier) contained in the product (g-5) was 81800 wppm.

[Reference Example 1] Acrylic copolymer (g-1)
50 parts of silica (particle size 3.3 μm, Mizusawa Chemical Co., Ltd., Mizukasil P-78A) was mixed in 50 parts, and ion-exchanged water was added so that the solid content concentration of the coating solution was 20%. To obtain a coating liquid 1.

Reference Example 2 Acrylic Copolymer (g-2)
50 parts of silica (particle size 3.3 μm, Mizusawa Chemical Co., Ltd., Mizukasil P-78A) was mixed in 50 parts, and ion-exchanged water was added so that the solid content concentration of the coating solution was 20%. To obtain coating liquid 2.

[Example 1] Acrylic copolymer (g-3)
50 parts of silica (particle size 3.3 μm, Mizusawa Chemical Co., Ltd., Mizukasil P-78A) was mixed in 50 parts, and ion-exchanged water was added so that the solid content concentration of the coating solution was 20%. To obtain coating liquid 3.

[Example 2] Acrylic copolymer (g-4)
50 parts of silica (particle size 3.3 μm, Mizusawa Chemical Co., Ltd., Mizukasil P-78A) was mixed in 50 parts, and ion-exchanged water was added so that the solid content concentration of the coating solution was 20%. To obtain coating solution 4.

[Comparative Example 1] Acrylic copolymer (g-5)
50 parts of silica (particle size 3.3 μm, Mizusawa Chemical Co., Ltd., Mizukasil P-78A) was mixed in 50 parts, and ion-exchanged water was added so that the solid content concentration of the coating solution was 20%. To obtain coating solution 5.

[Comparative Example 2] Acrylic copolymer (g-2)
To 50 parts, 5 parts of a surfactant (manufactured by Nippon Emulsifier Co., Ltd., trade name Newcol 707SF), silica (particle size 3.3).
μm, Mizusuka Chemical Co., Ltd., Mizukasil P-78A) was mixed in an amount of 50 parts, and ion-exchanged water was added so that the solid content concentration of the coating solution was 20% to obtain a coating solution 6. The content ratio (CX / AX) of the free surfactant (emulsifier) contained in the acrylic copolymer (g-2) is 5/50 = 1 × 10.
It is ⁵ wppm.

[Comparative Example 3] Acrylic copolymer (g-1)
20 parts of silica (particle size: 3.3 μm, Mizusuka Chemical Co., Ltd., Mizukasil P-78A) was mixed with 80 parts, and ion-exchanged water was added so that the solid content concentration of the coating solution was 20%. To obtain a coating liquid 7.

The ink-jet recording resin compositions of Reference Examples, Examples and Comparative Examples were applied so as to have a dry coating amount of 10 g / m ² , and an ink absorbing layer was formed on the art paper having a thickness of 190 μm (NK whitening loss 180). .0). The obtained recording sheet was printed with an Epson printer (Epson PM800C). Table 1 shows the evaluation results of the recording sheets obtained in Examples and Comparative Examples. further,
In the examples, when colloidal silica (manufactured by Nissan Chemical Co., Ltd., ST-50) is used instead of silica (particle size: 3.3 μm, Mizusuka Chemical Co., Ltd., Mizukasil P-78A), ink drying property, ink Absorbency is poor, but gloss,
An ink absorption layer excellent in ozone resistance could be obtained.

[0095]

[Table 1]

[0096]

INDUSTRIAL APPLICABILITY According to the present invention, an ink jet recording useful for producing a recording sheet which can form a recording layer having a good environmental gas property, has high gloss, is excellent in ink absorptivity and printing image quality (or printing quality). A resin composition can be provided.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08K 3/36 C08L 29/04 Z 4J100 C08L 29/04 33/08 33/08 101/00 101/00 B41J 3/04 101Y F-term (reference) 2C056 EA13 FC06 2H086 BA01 BA15 BA21 BA33 BA34 BA45 4F070 AA32 AA78 AC80 CA02 CA16 CB03 CB13 4J002 BB061 BC051 BE022 BG041 CK021 DE146 DE236 DJ006 DJ016 GS00 HA07 4J011 KA08 KA09 KB29 4J100 AJ02S AL03P AL03Q AL04P AL08Q AL08R AL09P AL10P AL11P AM15P AM21P AM21Q AP01S BA03P BA05P BA31Q BA32Q BA56S BA77Q CA05 CA06 EA07 FA03 FA20 JA01 JA13

Claims (9)

[Claims] 1. A resin composition for ink jet recording for forming a recording layer on a substrate, wherein the resin composition for ink jet recording comprises 3 to 60 mass% of a copolymer emulsion (a) based on the total amount of the composition. Inkjet recording comprising inorganic fine particles (b) of 40 to 97% by mass, wherein the content (CX) of free emulsifier (c) in the copolymer emulsion (a) satisfies the following relational expression. Resin composition. 0 wppm ≦ CX / AX <10000 wppm (Formula 1) (where CX is the content of the free emulsifier (c) in the copolymer emulsion (a), and AX is the copolymer weight of the copolymer emulsion (a). (The amount of combined components is shown, and wppm is mass ppm.) 2. The copolymer emulsion (a) comprises, based on the total amount of the copolymer, 27 to 70% by mass of a polymerizable unsaturated monomer (d) having an ion-forming group and a hydrolyzable silyl group. Acrylic copolymer emulsion (g) obtained by copolymerizing 0 to 4 mass% of the polymerizable unsaturated monomer (e) with 16 to 70 mass% of the other polymerizable unsaturated monomer (f). The resin composition for inkjet recording according to claim 1, wherein 3. The resin composition for inkjet recording according to claim 1, wherein the ionic property of the copolymer emulsion (a) is cationic. 4. Acrylic copolymer emulsion (g)
Is a water-based resin composition obtained by adding water to a resin solution obtained by solution polymerization to form an emulsion, and then removing the polymerization solvent.
The resin composition for inkjet recording described. 5. Acrylic copolymer emulsion (g)
Is polymerized in the presence of a radically polymerizable surfactant (h), The resin composition for ink jet recording according to claim 2. 6. The resin composition for ink jet recording according to claim 5, wherein the radically polymerizable surfactant (h) is cationic. 7. The resin composition for ink jet recording according to claim 3, wherein the copolymer emulsion (a) contains 0 to 30% by mass of the polyvinyl alcohol (i) based on the total amount of the composition. object. 8. The inorganic fine particles (c) have an average particle size of 3 to 30.
The resin composition for ink jet recording according to claim 1, wherein the resin composition is 0 nm silica. 9. A recording sheet comprising at least one recording layer formed of the ink jet recording resin composition according to claim 1. Description: