JPH0553312A - Preparation of microcapsule and photosensitive material formed by using microcapsule - Google Patents

Abstract

PURPOSE:To obtain the method for prepn. of the microcapsule having an excellent core material holding property. CONSTITUTION:This process for prepn. of the microcapsule consists in dispersing a core material contg. at least a polymerizable compd. in an oil drop form into an aq. medium contg. a copolymer contg. a repeating unit having a sulfonic acid group, a repeating unit contg. active hydrogen and a repeating unit having an anionic dissociation group in water and forming a resin wall consisting of an aminoaldehyde resin around the oil drops.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing microcapsules containing at least a polymerizable compound as a core substance, and a light-sensitive material using the microcapsules.

[0002]

2. Description of the Related Art A high-sensitivity light-sensitive material using microcapsules containing silver halide, a reducing agent, and a polymerizable compound is described in JP-A-61-275742. Further, there is disclosed a method for preparing microcapsules in which a hydrophobic core substance is emulsified in the presence of a water-soluble polymer having a sulfinic acid group, and then an aminoaldehyde wall is formed.
No. 152543. Further, the above-mentioned high-sensitivity light-sensitive material using the microcapsules obtained by the preparation method is described in JP-A-2-216151.

The above-mentioned publication describes a large number of copolymers having a repeating unit having a sulfinic acid group and other repeating units. Among them, when a copolymerized water-soluble polymer of a repeating unit having a sulfinic acid group and a repeating unit having no dissociative group is used, the core substance retention of the microcapsules is high, but the emulsion dispersion has an average particle size over time. Since the diameter or coefficient of variation was very unstable, there was a large variation in particle size depending on the production lot.
It was difficult to supply microcapsules with a constant particle size. Further, in the case of using a copolymer of a repeating unit having a sulfinic acid group and a repeating unit having an anionic dissociative group, or a water-soluble polymer having only a sulfinic acid group,
The stability of the emulsified dispersion was very high, but the microcapsule wall did not have sufficient compactness (retention of the core substance), and in the light-sensitive material using the microcapsules, the core substance was less than the capsule wall. There was a problem in that a spotted pattern was generated on the image.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a method for preparing a microcapsule which maintains a stable particle size and is excellent in core substance retention, and an excellent microcapsule having a high maximum concentration and a low minimum concentration. It is an object of the present invention to provide a light-sensitive material capable of providing an image.

[0005]

Means for Solving the Problems The above-mentioned problems are (1) an aqueous solution containing a copolymer polymer comprising a repeating unit having a sulfinic acid group, a repeating unit having active hydrogen, and a repeating unit having an anionic dissociative group. In the medium, a core substance containing at least a polymerizable compound is dispersed in the form of oil droplets, and a method for preparing a microcapsule in which a resin wall made of an aminoaldehyde resin is formed around the oil droplets, and (2)
In a light-sensitive material having at least a silver halide, a reducing agent, and a microcapsule containing a polymerizable compound as a core substance and a binder on a support, microencapsulation is prepared by the method for preparing a microcapsule described in (1) above. It was achieved by a light-sensitive material characterized by

According to the preparation method prior to the present invention, the sulfinic acid group of the water-soluble polymer reacts with the ethylenically unsaturated group contained in the hydrophobic substance to form a reaction product on the surface of the oil droplet particles of the hydrophobic substance. Are adsorbed, and due to charge repulsion of this reaction product or steric hindrance, coalescence of particles due to collision of oil droplets is prevented and formation of large particles is inhibited, and aminoaldehyde resin is deposited there. However, the retention of the core substance of the microcapsules was not sufficient. However, by introducing a group having active hydrogen as in the present invention,
It has become possible to supply microcapsules having a constant particle size and high core substance retention.

The microcapsules of the present invention contain an ethylene-based copolymer containing a repeating unit having a sulfinic acid group, a repeating unit having active hydrogen, and a repeating unit having an anionic dissociative group in an aqueous medium. It can be adjusted by introducing a hydrophobic substance containing a polymerizable compound having an unsaturated bond, emulsifying and dispersing, and further forming a resin wall made of an aminoaldehyde resin on the oil droplet surface. The copolymer polymer of the present invention can be represented by the following general formula (1).

General formula (1)-(A) _x- (B) _y- (C) _z -In the general formula (1), A is a repeating unit having a sulfinic acid group and B is a repeating unit having active hydrogen. Is C
Represents a repeating unit having an anionic dissociative group. Examples of the ethylenically unsaturated monomer having a sulfinic acid group represented by A above include sodium vinylbenzenesulfinate, potassium vinylbenzenesulfinate, N
-Sodium acryloyl-N-methylaminobenzenesulfinate, sodium allylsulfinate and
Ammonium vinylbenzenesulfinate can be mentioned. In the present invention, sodium vinylbenzenesulfinate, potassium vinylbenzenesulfinate and ammonium vinylbenzenesulfinate are preferred. The repeating unit having active hydrogen represented by B above is preferably obtained by copolymerization of a monomer represented by the following general formula.

[0009]

[Chemical 1]

In the formula, R ¹ is a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms (eg, methyl group, ethyl group, n-butyl group), halogen atom (eg, chlorine atom, bromine atom).
And a hydrogen atom or a methyl group is particularly preferable. G is -C
ONH _2, -OCONH _2, representing the -NHCONH _2.

L ¹ is --CON (R ² )-(R ² is a hydrogen atom,
Represents an alkyl group having 1 to 4 carbon atoms or a substituted alkyl group having 1 to 6 carbon atoms), -COO-, -NHCO-, -O
CO-

[0012]

[Chemical 2]

(R ³ and R ⁴ each independently represent a hydrogen atom, a hydroxyl group, a halogen atom or a substituted or unsubstituted alkyl group, alkoxy group, acyloxy group or aryloxy group),

[0014]

[Chemical 3]

L ² represents a linking group connecting L ¹ and G, m represents 0 or 1, and n represents 0 or 1. The linking group represented by L ² is specifically

[0016]

[Chemical 4]

It is represented by J ¹ , J ² , and J ³ may be the same or different and are —CO—, —SO ₂ —, —CO.
N (R ⁵ )-(R ⁵ is a hydrogen atom, an alkyl group (having 1 carbon atom)
To 6), a substituted alkyl group (having 1 to 6 carbon atoms), -SO ₂ N
(R ⁵ )-(R ⁵ has the same meaning as above), -N (R ⁵ ) -R ⁶
-(R ⁵ is as defined above, R ⁶ is an alkylene group having 1 to about 4 carbon atoms), -N (R ⁵ ) -R ⁶ -N (R ⁷ )-(R ⁵ ,
R ⁶ has the same meaning as above, and R ⁷ represents a hydrogen atom, an alkyl group (having 1 to 6 carbon atoms) or a substituted alkyl group (having 1 to 6 carbon atoms). ), - O -, - S -, - N (R 5) -CO-N (R
^{7) - (R 5, R} 7 are as defined ^{above), - N (R 5)} -S
^{_{O 2 -N (R 7) -}} (R 5, R 7 are as defined above), - C
OO -, - OCO -, - N (R 5) CO 2 - (R 5 is as defined above), and the like.

X ¹ , X ² and X ³ may be the same or different and each represents an alkylene group, a substituted alkylene group, an arylene group, a substituted arylene group, an aralkylene group or a substituted aralkylene group. Examples of the alkylene group include methylene, methylmethylene, dimethylmethylene, dimethylene,
Trimethylene, tetramethylene, pentamethylene, hexamethylene, decylmethylene, aralkylene groups such as benzylidene, and phenylene groups such as p-
Examples thereof include phenylene, m-phenylene and methylphenylene. As such an ethylenically unsaturated monomer having active hydrogen represented by the above general formula, acrylamide, methacrylamide,

[0019]

[Chemical 5]

[0020]

[Chemical 6]

[0021]

[Chemical 7]

And the like. Examples of the ethylenically unsaturated monomer having an anionic dissociative group represented by C above include potassium vinylbenzenesulfonate, sodium acrylate, and 2-acrylamido-2-
Examples thereof include sodium methylpropane sulfonate. In this case, the copolymerization ratio x of the repeating unit having a sulfinic acid group represented by the general formula (1) is 3-
The range of 90 mol% is preferable, and the range of 5-50 mol% is more preferable. The copolymerization ratio y of repeating units having active hydrogen is preferably in the range of 10 to 97 mol%,
The range of -95 mol% is more preferable. Specific examples of preferred water-soluble polymers in the present invention are shown below, but the present invention is not limited thereto. The copolymerization ratio of each component represents a weight percentage ratio.

[0023]

[Chemical 8]

[0024]

[Chemical 9]

[0025]

[Chemical 10]

[0026]

[Chemical 11]

The copolymer of the present invention, which comprises a repeating unit having a sulfinic acid group, a repeating unit having an active hydrogen, and a repeating unit having an anionic dissociative group, is used as an aqueous solution of about 0.1-20%. Is preferred. The molecular weight of the polymer is preferably in the range of 20,000-2,000,000, more preferably in the range of 3-1,000,000. The copolymer of the present invention, which comprises a repeating unit having a sulfinic acid group, a repeating unit having an active hydrogen, and a repeating unit having an anionic dissociative group, has a hydrophobic substance as a sulfinic acid group in an aqueous medium. The content of the ethylenically unsaturated group in the compound having an ethylenically unsaturated group is preferably 0.01 to 100 mol%, preferably 0.05 to 20 mol%. It is preferable to be included in.

The copolymer polymers comprising the repeating unit having a sulfinic acid group, the repeating unit having an active hydrogen, and the repeating unit having an anionic dissociative group may be used alone or in combination of two or more kinds. it can. In addition, a dispersion is prepared by using a copolymer of the present invention having a repeating unit having a sulfinic acid group, a repeating unit having an active hydrogen, and a repeating unit having an anionic dissociative group in combination with another water-soluble polymer. It can also be prepared. Preferred examples of the above water-soluble polymers that can be used in combination include polyvinyl alcohol, anion-modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, polyvinyl pyrrolidone, sodium polyacrylate, sulfonated polystyrene, ethylene / sodium maleate copolymer, Mention may be made of isobutylene / sodium maleate copolymer, polyacrylamide, sodium polyvinylbenzenesulfinate, pectin and gelatin.

The polymerizable compound that can be used in the present invention includes acrylic acid and salts thereof, acrylic acid esters, acrylamides, methacrylic acid and salts thereof, methacrylic acid esters, methacrylamides, maleic anhydride, Examples thereof include maleic acid esters, itaconic acid esters, styrenes, vinyl ethers, vinyl esters, N-vinyl heterocycles, allyl ethers, allyl esters and their derivatives.

Specific examples of preferred polymerizable compounds that can be used in the present invention include acrylic acid esters, such as n-butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, benzyl acrylate, furfuryl acrylate, ethoxyethoxyethyl. Acrylate, tricyclodecanyloxy acrylate, nonylphenyloxyethyl acrylate,
1,3-dioxolane acrylate, hexanediol diacrylate, butanediol diacrylate, neopentyl glycol diacrylate, tricyclodecane dimethylol diacrylate,

Trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, polyoxyethylenated bisphenol A diacrylate, 2- (2-hydroxy-1,1-dimethylethyl) -5-hydroxymethyl-5-ethyl-1,3-dioxane diacrylate, 2
-(2-hydroxy-1,1-dimethylethyl) -5,
5-dihydroxymethyl-1,3-dioxane triacrylate, triacrylate of propylene oxide adduct of trimethylolpropane, hexaacrylate of caprolactone adduct of dipentaerythritol, polyacrylate of hydroxypolyether, polyester acrylate and polyurethane acrylate Can be mentioned.

As other specific examples, regarding methacrylic acid esters, methyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, butanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate,
Examples thereof include pentaerythritol tetramethacrylate and dioxymethacrylate of polyoxyalkylenated bisphenol A.

The above polymerizable compounds may be used alone or in combination of two or more kinds. Regarding a light-sensitive material in which two or more kinds of polymerizable compounds are used in combination, JP-A-62-210445 is used.
It is described in the official gazette. A substance in which a polymerizable functional group such as a vinyl group or a vinylidene group is introduced into the chemical structure of the reducing agent can also be used as the polymerizable compound.

The following hydrophobic substances having no ethylenically unsaturated group may be contained together with the polymerizable compound. In that case, the hydrophobic substance is preferably contained in a proportion of 0 to 50% of the polymerizable compound.

Examples of the hydrophobic substance having no ethylenically unsaturated group include natural mineral oil, animal oil, vegetable oil and synthetic oil. Examples of mineral oils are petroleum and its fractions, such as kerosene, gasoline, naphtha and paraffin oil. Examples of animal oils include fish oil and lard oil. Examples of vegetable oils include peanut oil, flaxseed oil, soybean oil, castor oil and corn oil. Examples of synthetic oils include biphenyl compounds (eg, isopropyl biphenyl, isoamyl biphenyl, etc.), terphenyl compounds (West German Patent Publication 2,1).
53,635), a phosphoric acid compound (for example, triphenyl phosphate, etc.), a naphthalene compound (for example, see West German Laid-Open Patent 2,141,194),
Methane compound (for example, West German published patent 2,153,63
4), phthalic acid compounds (eg, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, etc.), salicylic acid compounds (eg, ethyl salicylate), and the like.

In the mixture of the compound having an ethylenically unsaturated group and the hydrophobic substance having no ethylenically unsaturated group consisting of natural mineral oil, animal oil, vegetable oil, and synthetic oil, pesticide, medicine, Fragrances, chemical products, adhesives,
Liquid crystals, detergents, dyes, dye precursors, color developers, catalysts, rust preventives and the like can be appropriately mixed depending on the purpose of use. The wall material of the microcapsule of the present invention is amino-
Aldehyde resin walls, especially melamine-formaldehyde resin walls are preferred. Incidentally, JP-A-63-3253
As in the light-sensitive material described in Japanese Patent Laid-Open No. 5, it is preferable that the amount of residual aldehyde is not more than a certain value. The method is JP-A-6.
No. 3-142343 and the like. The average particle size of the microcapsules is 1 to 50 μm, preferably 3 to 2
It is 0 μm. The particle size distribution of the microcapsules is preferably uniform over a certain value, as in the light-sensitive material described in JP-A-63-5334. Also,
The film thickness of the microcapsules is preferably within a certain range with respect to the particle diameter, as in the light-sensitive material described in JP-A-63-81336.

When the silver halide is contained in the microcapsules, the average grain size of the silver halide grains is preferably ⅕ or less, and preferably ⅕ or less of the average size of the microcapsules. Is more preferable. By setting the average grain size of silver halide grains to be one fifth or less of the average size of microcapsules, a uniform and smooth image can be obtained. When the silver halide is contained in the microcapsules, it is preferable that the silver halide be present in the wall material that constitutes the outer shell of the microcapsules. Regarding a light-sensitive material containing silver halide in the wall material of microcapsules, JP-A-62-16
It is described in Japanese Patent No. 9147.

The silver halide, reducing agent, support color image-forming substance and base precursor used in the photothermographic material of the present invention (hereinafter simply referred to as photosensitive material) will be described below.

The silver halide used in the light-sensitive material of the present invention is any of silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodide, silver iodobromide and silver chloroiodobromide. Particles can also be used. The silver halide grains in the photographic emulsion are cubic,
Those having regular crystals such as octahedron, dodecahedron and tetradecahedron, those having an irregular crystal system such as spheres and plates, those having crystal defects such as twin planes, or A composite form of them may be used.

The grain size of the silver halide may be fine grains of about 0.01 micron or less or large grains having a projected area diameter of up to about 10 microns, and it may be a polydisperse emulsion or US Pat. No. 3,574,628. No., 3,655,394
And monodisperse emulsions described in British Patent No. 1,413,748 and the like may be used.

Further, tabular grains having an aspect ratio of about 5 or more can be used in the present invention. Tabular grains are described in Gutoff, Photographic Science and Engineering.
Engineering), Vol. 14, pp. 248-257 (1970)
); U.S. Pat. Nos. 4,434,226 and 4,41
4,310, 4,433,048, 4,43
It can be easily prepared by the method described in 9,520 and British Patent 2,112,157.

The crystal structure may be uniform, may have different halogen compositions inside and outside, or may have a layered structure. Further, silver halides having different compositions may be joined by epitaxial joining,
Further, it may be bonded with a compound other than silver halide such as silver rhodanide and lead oxide. Also, the halogen composition,
Two or more kinds of silver halide grains having different crystal habits, grain sizes and the like can be used in combination.

The silver halide photographic emulsion which can be used in the present invention is, for example, Research Disclosure (RD) No1.
7643 (Dec. 1978), pp. 22-23, "I.
"Emulsion preparation and types", and No. 18716 (November 1979), page 648, and the like.

The silver halide emulsion is usually used after physical ripening, chemical ripening and spectral sensitization. Additives used in such a process are described in Research Disclosure No. 17643 and No. 18716, and the relevant portions are summarized in the table below. Known photographic additives that can be used in the present invention are also the above-mentioned two research products.
It is described in the disclosure, and the relevant parts are shown in the table below.

Additive type RD17643 RD18716 Chemical sensitizer, page 23, page 648, right column, sensitivity enhancer, same as above, spectral sensitizer, page 23-24, page 648, right column-supersensitizer, page 649, right column, antifoggant 24- Page 25 Page 649 Right column ~ and Stabilizer

Details of the above-mentioned silver halide emulsion and photographic additives are described in "Public Technology No. 5" (Astec Co., Ltd., issued March 22, 1991), pages 2 to 17. The amount of silver halide used is 1
0.001 to 10 g, preferably 0.0 in terms of silver per m ^2.
It is 5 to 2 g. Further, in the present invention, an organic silver salt can be used together with silver halide. The organic silver salt is described on pages 17 to 18 of "Public Technology No. 5".

The reducing agent that can be used in the light-sensitive material of the present invention has a function of reducing silver halide and / or a function of accelerating (or suppressing) the polymerization of the polymerizable compound. Examples of the reducing agent having the above function include hydroquinones, catechols, p-aminophenols, p-phenylenediamines, 3-pyrazolidones, 3-aminopyrazoles, 4-amino-5-pyrazolones and 5-amino. Uracils, 4,5-dihydroxy-6-aminopyrimidines, reductones, aminoreductones, o-
Or p-sulfonamidophenols, o- or p
-Sulfonamidonaphthols, 2,4-disulfonamidophenols, 2,4-disulfonamidonaphthols, o- or p-acylaminophenols, 2-
Sulfonamide indanones, 4-sulfonamido-5
-Pyrazolones, 3-sulfonamidoindoles, sulfonamide pyrazolobenzimidazoles, sulfonamide pyrazolotriazoles, α-sulfonamido ketones, hydrazines and the like.

The above-mentioned various reducing agents are described in detail on pages 18 to 35 of the above-mentioned known technology No. 5.
The addition amount of the reducing agent can be widely varied, but is generally 0.1 to 1500 mol%, preferably 10 to 10 mol% with respect to the silver salt.
It is 300 mol%.

Materials that can be used for the support include glass, paper, woodfree paper, baryta paper, coated paper, cast coated paper, synthetic paper, metal and its analogs, polyester, polyethylene, polypropylene, acetyl cellulose, cellulose. Ester, polyvinyl acetal,
Examples thereof include films such as polystyrene, polycarbonate, polyethylene terephthalate, and polyimide, and paper laminated with a resin material or a polymer such as polyethylene. For details, refer to “Public Technology No. 5” above.
No. ”pp. 144-149. Among them, the preferred support of the present invention is a polymer film, and it is particularly preferred that it is a polymer film having a thickness of 50 μm or less in view of the thermal conductivity described above.

Further, in order to coat the photosensitive layer on the support,
It is preferable to provide the undercoat layer described in JP-A-61-113058 on the polymer film, or to provide a metal vapor deposition film of aluminum or the like on the polymer film.
Therefore, as the support of the light-sensitive material of the present invention, 50 μm
A polymer film having the following thickness and having an aluminum vapor deposition film is particularly preferable.

The microcapsules of the present invention may further contain a color image forming substance. The color image-forming substance that can be used is not particularly limited, and various types can be used. That is, the substance itself is colored (dye or pigment), the energy itself is colorless or light-colored but external energy (heat, pressure, light irradiation, etc.) or another component (developing agent) A substance (color former) that develops a color upon contact with is included in the color image forming substance. As the color image forming substance, as described in JP-A-62-187346, dyes and pigments which are excellent in image stability and colored themselves are preferable.

Commercially available dyes and pigments as well as known dyes and pigments described in various documents can be used. For references, see Color Index (CI) Handbook,
"Latest Pigment Handbook" edited by Japan Pigment Technology Association (1977), "Latest Pigment Application Technology" CMC Publishing (1986), "Printing Ink Technology" (CMC Publishing, 1984), etc. For details of the color image-forming substance that can be used in the present invention and the technique for using the same, refer to the above-mentioned "Public Technology No. 5".
No. "p. 35 to 50. In particular, the pigment is preferable because it has excellent light fastness and causes less blurring of an image during transfer. The pigment is 5-6 with respect to 100 parts by weight of the polymerizable compound.
It is preferable to use 0 part by weight.

A base precursor can be used in the light-sensitive material of the present invention in order to obtain a clear image. As the base precursor, base precursors of inorganic bases and organic bases (decarboxylation type, thermal decomposition type, reaction type, complex salt forming type, etc.) can be used. Details of these base precursors and the techniques for using them are described in "Public Technology No. 5," pages 55 to 86.

Preferred base precursors are JP-A-59-180549, JP-A-59-180537, JP-A-59-195237, JP-A-61-32844 and JP-A-61.
-36743, 61-51140, 61-52
No. 638, No. 61-52639, No. 61-53631.
No. 61-53634, No. 61-53635, No. 61-53636, No. 61-53637, No. 61-
53638, 61-53639, 61-536.
40, 61-55644, 61-55645.
No. 61, No. 61-55646, No. 61-84640, No. 61-107240, No. 61-2119950, No. 6
1-251840, 61-252544, 61
-313431, 63-316740, 64-
No. 68746 and Japanese Patent Application No. 1-54452, salts of organic acids and bases which are decarboxylated by heating,
Further, JP-A-59-157637 and JP-A-59-1669.
Compounds capable of eliminating a base by heating as described in each of Nos. 43 and 63-96159 are mentioned.

The base precursor of the present invention is 50
It is preferable to release the base at ℃ ~ 200 ℃, 80
More preferably, the release is carried out at a temperature of 180 to 180 ° C. The base precursor used in the light-sensitive material of the present invention is preferably contained in microcapsules, in which case,
As described in Japanese Patent Application No. 2-270159, a base precursor composed of a salt of a carboxylic acid and an organic base described below, which has a solubility of 1% or less in water and a polymerizable compound at 25 ° C., is particularly preferable.

In the present invention, when the base precursor is contained in the microcapsules, a photosensitive composition in which the base precursor is directly solid-dispersed in a polymerizable compound may be used (Japanese Patent Laid-Open No. 64-32521, JP-A-64-22551). Kaihei 1-2
It is particularly preferable to use a photosensitive composition in which a base precursor is dispersed in water and emulsified in a polymerizable compound. (JP-A-63-21
No. 8964, Japanese Patent Application No. 1-182245, Japanese Patent Application No. 1-1
No. 60148, each gazette and description) Here, when dispersing the base precursor in water, it is preferable to use a nonionic or amphoteric water-soluble polymer.

Examples of nonionic water-soluble polymers are polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polymethyl vinyl ether, polyacryloylmorpholine, polyhydroxyethyl acrylate, polyhydroxyethyl methacrylate-co-acrylamide, hydroxyethyl cellulose, hydroxy. Examples thereof include propyl cellulose and methyl cellulose. Further, as the amphoteric water-soluble polymer,
Mention may be made of gelatin.

The above water-soluble polymer is preferably contained in the base precursor in a proportion of 0.1 to 100% by weight, more preferably 1 to 50% by weight. The base precursor is preferably contained in the dispersion in an amount of 5 to 60% by weight, more preferably 10 to 50% by weight. The base precursor is preferably contained in a proportion of 2 to 50% by weight with respect to the polymerizable compound,
It is more preferable that the content is 5 to 30% by weight.

In order to reduce the solubility of the base precursor in the polymerizable compound, polyethylene glycol, polypropylene glycol, benzoic acid amide, cyclohexylurea, octyl alcohol, dodecyl alcohol, stearyl alcohol, stearamide and the like can be used in the polymerizable compound. OH, -SO ₂ NH _2, -CONH
_{It is} also possible to add a compound having a hydrophilic group such as ₂ , ₂ , -NHCONH ₂ .

In the present invention, in addition to the reducing agent, known antioxidants can be used together with the polymerizable compound to prevent oxidative deterioration of the polymerizable compound and to prevent oxygen oxidation during heat development. As such an antioxidant, 2,2 '
-Methylene-bis- (4-methyl-6-t-butylphenol), 2,6-di-t-butylphenol, 2,
2'-butylidene-bis- (4-methyl-6-t-butylphenol), 2-t-butyl-6- (3'-t-butyl-5'-methyl-2'-hydroxybenzyl) -4
-Methylphenyl acrylate, 4,4'-thio-bis- (3-methyl-6-t-butylphenol) and other phenolic antioxidants; diphenyldecyl phosphite,
Triphenyl phosphite, tris- (2,4-di-t
-Butylphenyl) phosphite, tris- (2-ethylhexyl) phosphite and other phosphite antioxidants; dilauryl-3,3'-thio-dipropionic acid ester, pentaerythritol-tetrakis- (β-lauryl-thio -Propionic acid ester), thio-dipropionic acid, and other sulfur-based antioxidants; phenyl-1-naphthylamine, 6-ethoxy-2,2,4-trimethyl-
Examples thereof include amine antioxidants such as 1,2-dihydroquinoline and dioctyliminodibenzyl.

Other components that can be used in the light-sensitive material of the present invention will be described below. Details of these components are described in the above-mentioned "Known Technique No. 5", pp. 98-144 and 86-.
It is described on page 88. The binder that can be used in the light-sensitive material can be contained in the light-sensitive layer alone or in combination. It is preferable to mainly use a hydrophilic binder. As the hydrophilic binder, a transparent or translucent hydrophilic binder is typical. For example, natural substances such as gelatin, gelatin derivatives, cellulose derivatives, starch, gum arabic, etc., and polyvinyl alcohol, polyvinylpyrrolidone, acrylamide polymers, etc. Including synthetic polymeric materials such as water soluble polyvinyl compounds. Other synthetic polymeric materials include dispersed polyvinyl compounds in the form of latices, which increase the dimensional stability of photographic materials in particular. The photosensitive material using a binder is described in JP-A-61-69062. Further, regarding a light-sensitive material using a binder together with microcapsules, see JP-A-62-209525.
It is described in the official gazette.

As the anti-smudge agent used in the light-sensitive material, solid particles at room temperature are preferable. Specific examples thereof include starch particles described in British Patent No. 1232347, polymer fine powder described in U.S. Pat. No. 3,625,736, and microcapsule particles containing no color former described in British Patent No. 12359991. US Patent No. 2
Examples include cellulose fine powder described in No. 711375, talc, kaolin, bentonite, wax, inorganic particles such as zinc oxide, titanium oxide and alumina. The average particle size of the particles is preferably in the range of 3 to 50 μm in volume average diameter, and more preferably in the range of 5 to 40 μm. As described above, when the oil droplets of the polymerizable compound are in the microcapsule state, it is more effective that the particles are larger than the microcapsules. Various image formation accelerators can be used in the light-sensitive material.

The image forming accelerator has a function of promoting transfer of a base or base precursor, promoting reaction of a reducing agent with a silver salt, and promoting immobilization of a dye-donor substance by polymerization. Are classified into the above-mentioned bases or base precursors, nucleophilic compounds, oils, thermal solvents, surfactants, compounds that interact with silver or silver salts, compounds having an oxygen scavenging function, and the like. However, these substance groups generally have a composite function and usually have some of the above-mentioned accelerating effects together. Details thereof are described in the specifications and publications of U.S. Pat. No. 4,678,739, columns 38 to 40, JP-A-62-209443 and the like. The hexavalent metal compound described in Japanese Patent Application No. 2-272878 is also effective.

In the system for polymerizing a part of the polymerizable compound in which a latent image of silver halide is not formed on the light-sensitive material,
A thermal or photopolymerization initiator can be used for the purpose of initiating polymerization or for polymerizing an unpolymerized polymerizable compound after image transfer. Examples of thermal polymerization initiators include azo compounds, organic peroxides, inorganic peroxides, sulfinic acids and the like. Details thereof are described in pages 6 to 18 and the like of “Addition Polymerization / Ring-Opening Polymerization” (1983, Kyoritsu Shuppan) edited by the Society for Polymer Science, Editorial Committee for Polymer Experiments.

Examples of the photopolymerization initiator include benzophenones, acetophenones, benzoins, thioxanthones and the like. Details of these are described in "UV Curing System" (1989, Comprehensive Technical Center), pp. 63-147. Various surface active agents can be used in the light-sensitive material for the purpose of coating aid, improvement of peeling property, improvement of sliding property, antistatic property, acceleration of development and the like. Specific examples of the surfactant are disclosed in JP-A-62-173.
463, 62-183457 and the like.

An antistatic agent can be used in the light-sensitive material for the purpose of antistatic. As an antistatic agent, it is described in Research Disclosure, November 1978, No. 17643 (page 27). In the photosensitive layer of the photosensitive material,
Dyes or pigments may be added for the purpose of preventing halation or irradiation. A light-sensitive material containing a white pigment added to the light-sensitive layer.
It is described in the official gazette.

A dye having the property of being decolorized by heating or light irradiation may be contained in the microcapsules of the light-sensitive material. The dye having the property of being decolorized by heating or light irradiation can function as a yellow filter in a conventional silver salt photographic system. The light-sensitive material using the dye having the property of being decolorized by heating or irradiation with light as described above is described in JP-A-63-974940.

When a solvent of a polymerizable compound is used in the light-sensitive material, it is preferable to use it by enclosing it in a microcapsule different from the microcapsule containing the polymerizable compound.
A photosensitive material using an organic solvent miscible with a polymerizable compound encapsulated in microcapsules is disclosed in Japanese Patent Laid-Open No.
It is described in JP-A 2-209524.

Various antifoggants or photographic stabilizers can be used in the present invention. For example,
Azoles and azaindenes described on pages 24 to 25 of RD17643 (1978), JP-A-59-168442.
Nitrogen-containing carboxylic acids and phosphoric acids described in JP-A No. 59-111636, mercapto compounds and metal salts thereof described in JP-A No. 59-111636, and acetylene compounds described in JP-A No. 62-87957 are used. ..

Various development stoppers can be used in the light-sensitive material for the purpose of always obtaining a constant image with respect to the processing temperature and processing time during development. The term "development terminating agent" as used herein refers to a compound that immediately neutralizes or reacts with a base to reduce the concentration of the base in the film to stop the development after proper development, or to inhibit development by interacting with silver and a silver salt. Compound. Specific examples thereof include an acid precursor that releases an acid when heated, an electrophilic compound that causes a substitution reaction of a coexisting base when heated, or a nitrogen-containing heterocyclic compound, a mercapto compound and a precursor thereof. More specifically, JP-A-62-253159, pages (31) to (32), JP-A-1-724
No. 79, No. 1-3471, etc. are described.

In addition to the above, examples of optional components that can be contained in the photosensitive layer and the usage thereof are also described in the specification of the above-mentioned series of photosensitive materials and Research Disclosure Vol. 170, 197.
No. 17029 (Pages 9 to 15), June 1996. As a layer that can be optionally provided in the photosensitive material,
Examples thereof include an image receiving layer, a heating element layer, an antistatic layer, an anti-curl layer, a peeling layer, a cover sheet or a protective layer, and an antihalation layer (colored layer).

A photosensitive material using a heating element layer is disclosed in JP-A-61-294434, and a photosensitive material provided with a cover sheet or a protective layer is disclosed in JP-A-62-2.
Japanese Patent Application Laid-Open No. 63-101842 discloses a photosensitive material provided with a colored layer as an antihalation layer.
Each of them is described in Japanese Patent Publication No. Furthermore, examples of other auxiliary layers and their usages are also described in the specification of the series of photosensitive materials described above.

In the image forming method using the light-sensitive material of the present invention, it is general to use the image-receiving material together with the light-sensitive material. The image receiving material will be described below. The details are described in "Public Technology No. 5", pages 149 to 178. The image receiving material may be only the support, but it is preferable to provide an image receiving layer on the support. The support of the image receiving material is not particularly limited, but like the support of the light-sensitive material, glass, paper, high-quality paper, baryta paper, coated paper, cast coated paper, synthetic paper, cloth, metal and analogs thereof. , Polyester, polyethylene, polypropylene, acetyl cellulose, cellulose ester, polyvinyl acetal,
Examples thereof include films such as polystyrene, polycarbonate and polyethylene terephthalate, and paper laminated with a resin material or a polymer such as polyethylene.

When a porous material such as paper is used as the support of the image receiving material, it is disclosed in JP-A-62-20953.
It is preferable that the image receiving material described in Japanese Patent Laid-Open No. 0 have a certain smoothness. Further, an image receiving material using a transparent support is described in JP-A-62-209531. The image-receiving layer of the image-receiving material is composed of a white pigment, a binder, and other additives, and the white pigment itself or voids between the particles of the white pigment increase the receptivity of the polymerizable compound.

The white pigment used in the image-receiving layer is an inorganic white pigment, for example, oxides of silicon oxide, titanium oxide, zinc oxide, magnesium oxide, aluminum oxide, magnesium sulfate, barium sulfate, calcium sulfate, carbonic acid. Alkaline earth metal salts such as magnesium, barium carbonate, calcium carbonate, calcium silicate, magnesium hydroxide, magnesium phosphate, and magnesium hydrogen phosphate, as well as aluminum silicate, aluminum hydroxide, zinc sulfide, sugar clay, talc , Kaolin, zeolite, acid clay, activated clay, glass and the like. Organic white pigments include polyethylene, polystyrene, benzoguanamine resins, urea-formalin resins,
Examples thereof include melamine-formalin resin and polyamide resin. These white pigments may be used alone or in combination, but those having a high oil absorption amount with respect to the polymerizable compound are preferable.

As the binder used in the image-receiving layer of the present invention, a water-soluble polymer, a polymer latex, a polymer soluble in an organic solvent or the like can be used. As the water-soluble polymer, for example, carboxymethyl cellulose, hydroxyethyl cellulose, cellulose derivatives such as methyl cellulose, gelatin, phthalated gelatin, casein, proteins such as ovalbumin, starches such as dextrin, etherified starch, polyvinyl alcohol,
Polyvinyl alcohol partial acetal, poly-N-vinylpyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, synthetic polymers such as polyvinyl imidazole, polyvinyl pyrazole, polystyrene sulfonic acid, etc., locust bean gum, pullulan, gum arabic, alginic acid Examples include soda.

Examples of the polymer latex include styrene-butadiene copolymer latex, methyl methacrylate / butadiene copolymer latex, polymers of acrylic acid ester and / or methacrylic acid ester, copolymer latex, ethylene / vinyl acetate copolymer. Polymer latex etc. are mentioned. Examples of the polymer soluble in an organic solvent include polyester resin, polyurethane resin, polyvinyl chloride resin, polyacrylonitrile resin and the like.

The above binders may be used in combination of two or more kinds, and may also be used in a ratio such that the two kinds of binders cause phase separation. As an example of such usage, JP-A-1-154789
There is a description in the official gazette. The average particle size of the white pigment is 0.
1 to 20 μ, preferably 0.1 to 10 μ, and the coating amount is 0.1 g to 60 g, preferably 0.5 g to 30 g
The range is. The weight ratio of the white pigment to the binder is preferably 0.01 to 0.4 of the binder, and more preferably 0.03 to 0.3 with respect to the pigment 1.

The image-receiving layer may contain various additives as described below, in addition to the binder and the white pigment. For example, when a color-developing system including a color-developing agent and a color-developing agent is used, the image-receiving layer may contain the color-developing agent. Typical developers include phenols, organic acids or salts thereof, or esters, but when a leuco dye is used as a color image-forming substance, a zinc salt of a salicylic acid derivative is preferable, Above all,
Zinc 3,5-di-α-methylbenzyl salicylate is preferred. The above color developer is preferably contained in the image receiving layer in a coating amount of 0.1 to 50 g / m ² . More preferably, it is in the range of 0.5 to 20 g / m ² .

The image receiving layer may contain a thermoplastic compound. When the image receiving layer contains a thermoplastic compound, it is preferable that the image receiving layer itself is formed as an aggregate of thermoplastic compound fine particles. The image-receiving layer having the above-described structure has an advantage that a transfer image can be easily formed and a glossy image can be obtained by heating after the image formation.
The thermoplastic compound is not particularly limited and may be arbitrarily selected from known plastic resins (plastics) and waxes. However, the glass transition point of the thermoplastic resin and the melting point of the wax are preferably 200 ° C. or lower. Regarding the image-receiving material having the image-receiving layer containing the above-mentioned fine particles of the thermoplastic compound, JP-A-Sho 6 is used.
2-280071 and 62-280739.

The image receiving layer may contain a photopolymerization initiator or a thermal polymerization initiator. In image formation using an image receiving material, a color image forming substance is transferred together with an unpolymerized polymerizable compound. Therefore, a photopolymerization initiator or a thermal polymerization initiator can be added to the image-receiving layer for the purpose of curing (fixing) the unpolymerized polymerizable compound. An image receiving material having an image receiving layer containing a photopolymerization initiator is disclosed in JP-A-62-161149, and an image receiving material having an image receiving layer containing a thermal polymerization initiator is disclosed in JP-A-62-161149.
Each of them is described in Japanese Patent Publication No. 210444.

In the following, in the image forming method of the present invention, the step of imagewise exposure, the imagewise exposure, or after the imagewise exposure, the photosensitive material is heated from the surface of the support having no photosensitive layer coated thereon. And a series of steps such as a step of superposing the surface of the photosensitive material coated with the photosensitive layer and the image receiving material and pressurizing the same.

As the exposure method in the imagewise exposure step, various exposure means can be used, but in general, a latent image of silver halide is obtained by imagewise exposure of radiation including visible light. The type of light source and the amount of light exposure depend on the light-sensitizing wavelength of silver halide (sensitized wavelength when dye-sensitized)
Alternatively, it can be selected according to the sensitivity.

Typical light sources include low-energy radiation sources such as natural light, ultraviolet rays, visible light, infrared rays, fluorescent lamps, tungsten lamps, mercury lamps, halogen lamps, xenon flash lamps, laser light sources (gas laser, solid laser, Chemical lasers, semiconductor lasers, etc.), light emitting diodes, plasma arc tubes, FOTs and the like. In special cases, it is possible to use X-rays, γ-rays, electron beams, etc., which are high-energy ray sources.

The light-sensitive material of the present invention, particularly in the case of a full-color light-sensitive material, is composed of microcapsules having photosensitivity in a plurality of spectral regions, and therefore it is necessary to perform image exposure with a plurality of corresponding spectral lines. Is. Therefore, the light sources may be used alone or in combination of two or more. When selecting the light source,
It goes without saying that a light source suitable for the photosensitive wavelength of the photosensitive material is selected, but it can be selected in consideration of whether image information passes through an electric signal, the processing speed of the entire system, compactness, power consumption, and the like.

When the image information does not pass through an electric signal, for example, direct photography of a landscape or a person, direct copying of an original image,
In the case of exposing through a positive such as a reversal film, a camera, an exposure device for printing such as a printer or an enlarger, an exposure device of a copying machine, or the like can be used. In this case, a two-dimensional image can be simultaneously exposed by so-called one shot, or scanning exposure can be performed through a slit or the like. You can also stretch or reduce the original image. In this case, the light source is not a monochromatic light source such as a laser but a light source such as a tungsten lamp or a fluorescent lamp, or a combination of a plurality of monochromatic light sources.

When image information is recorded via an electric signal, as an image exposure device, a light emitting diode and various lasers may be used in combination according to the color sensitivity of the heat-developable color photosensitive material. Various devices known as an image display device (CRT, liquid crystal display, electroluminescence display, electrochromic display, plasma display, etc.) can also be used. In this case, the image information includes an image signal obtained from a video camera or an electronic still camera, a television signal represented by Nippon Television Signal Standard (NTSC),
An image signal obtained by dividing an original image into a large number of pixels with a scanner or the like, or an image signal stored in a recording material such as a magnetic tape or a disk can be used.

Upon exposure of a color image, LEDs, lasers, fluorescent tubes and the like are used in combination according to the color sensitivity of the light-sensitive material. However, a plurality of the same materials may be used in combination, or different kinds of materials may be used in combination. May be. The color sensitivity of photosensitive materials is R (red), G (green), B (blue) in the photographic field.
Photosensitivity is normal, but in recent years it is often used in combination with UV, IR, etc., and the range of use of the light source is expanding. For example, the color sensitivity of the photosensitive material is (G, R, IR)
Or (R, IR (short wave), IR (long wave)),
(UV (short wave), UV (medium wave), UV (long wave)), (U
Spectral regions such as V, B, G) are utilized. The light source may be a combination of different types such as a combination of two LED colors and a laser. The light emitting tube or element may be scanned and exposed by using a single tube or element for each color, or an array tube may be used to increase the exposure speed. Examples of usable arrays include an LED array, a liquid crystal shutter array, and a magneto-optical element shutter array.

The image display device described above is a CRT.
As described above, there are color display and monochrome display, but a method of performing exposure several times by combining the monochrome display with a color filter may be adopted. Existing 2
The three-dimensional image display device may be used by making it one-dimensional like FOT, or by dividing one screen into several pieces and using them in combination with scanning.

By the above imagewise exposure, a latent image is obtained on the silver halide contained in the microcapsules. The image forming method of the present invention includes a step of heating the photosensitive material at the same time as the imagewise exposure or after the imagewise exposure to thermally develop the photosensitive material. Thermal development is preferably carried out by heating from the surface of the support on which the photosensitive layer of the photosensitive material is not coated.

As this heating means, there is disclosed in JP-A-61-29.
As in the light-sensitive material described in Japanese Patent No. 4434, a heating element layer may be provided on a surface of a support on which the light-sensitive layer of the light-sensitive material is not coated to heat the support. Further, as described in JP-A-61-147244, a hot plate, an iron, and a heat roller are used, or as described in JP-A-62-144166, a photosensitive material is sandwiched between a heat roller and a belt. A method of heating may be used.

That is, the photosensitive material may be brought into contact with a heating element having a surface area larger than the area of the photosensitive material to heat the entire surface at the same time, or a heating element having a smaller surface area (heating plate,
The entire surface may be heated over time by bringing it into contact with a heating roller, a heating drum, etc. and scanning it.
In addition to the heating method in which the heating element and the photosensitive material are brought into direct contact with each other as described above, electromagnetic waves, infrared rays, hot air, etc. can be applied to the photosensitive material to heat them in a non-contact state.

In the image forming method of the present invention, thermal development is carried out by heating the surface of the photosensitive material on the support on which the photosensitive layer is not coated. At this time, the photosensitive layer is coated. The surface that is marked may be in direct contact with the air,
It may be covered with a heat insulating material or the like in order to keep it warm so as not to release heat. In this case, it is preferable not to apply a strong pressure (10 kg / cm ² or more) to the photosensitive layer so as not to break the microcapsules contained in the photosensitive layer.

The heat development by heating is carried out at the same time as the imagewise exposure or after the imagewise exposure, but it is preferable to perform the heating after 0.1 seconds or more has passed after the imagewise exposure. The heating temperature is generally 60 ° C to 250 ° C, preferably 80 ° C to 180 ° C.
And the heating time is between 0.1 and 20 seconds, preferably between 0.5 and 5 seconds.

The photosensitive material can be subjected to heat development as described above to polymerize the polymerizable compound in the portion where the latent image of silver halide is formed or the portion where the latent image of silver halide is not formed. In the case where a polymerization inhibitor is formed in the latent image formed portion of silver halide by the reaction with a reducing agent, heat or photopolymerization initiation which has been added in advance in the photosensitive layer, preferably in microcapsules. It is also possible to decompose the agent by heating or irradiating with light to uniformly generate radicals and polymerize the polymerizable compound in a portion where a latent image of silver halide is not formed. In this case, in addition to the above-mentioned imagewise exposure step and heat development step, if necessary, a whole surface heating or whole surface exposure step is required, and the method is the same as the imagewise exposure step or the heat development step.

In the image-forming method of the present invention, the unpolymerized polymerizable compound is transferred to the image-receiving material by the step of applying pressure in the state where the light-sensitive material having a polymer image and the image-receiving material are superposed on the photosensitive layer, A color image can be obtained on the image receiving material. A conventionally known method can be used as the pressurizing method.

For example, the photosensitive material and the image receiving material may be sandwiched between press plates such as a presser, or pressure may be applied while being conveyed by using a pressure roller such as a nip roll. The pressure may be applied intermittently by a dot impact device or the like.
Further, high pressure air can be wiped with an air gun or the like, or can be pressurized with an ultrasonic wave generator, a piezoelectric element or the like. The pressure required for pressurization is 500 kg / cm ² or more,
It is preferably 800 kg / cm ² or more. However, 500 kg / cm when pressure is applied together with heating at 40 ° to 120 ° C
It may be ² or less.

The light-sensitive material of the present invention has many uses such as color photographing and printing light-sensitive materials, printing light-sensitive materials, computer graphic hard copy light-sensitive materials, and light-sensitive materials for copying machines. It is possible to create compact and inexpensive image forming systems such as copiers, printers, and simple printers.

[0099]

【Example】

Example 1 Preparation of silver halide emulsion (EB-1) 24 g of lime-treated inert gelatin was added to distilled water, and 4
After dissolving at 0 ° C. for 1 hour, 1 g of KBr was added, and 1
The pH was adjusted to 3.2 by adding N-sulfuric acid.

After 10 mg of (AGS-1) was added to this solution, solutions I and II were added simultaneously at 75 ° C. over 15 minutes. Further, the liquid III and the liquid IV were added simultaneously at 75 ° C. over 15 minutes. After the addition is complete, adjust the pH to 1N NaO
The pAg was adjusted to 9.4 by addition of 6.0 to H with KBr and (AZ-1) 1.9 mg and (AZ-2) 2.3 mg.
Was added and the mixture was aged at 75 ° C. for 60 minutes. After aging (SB-1)
480 mg was added, and 20 minutes after the addition, the temperature was raised to 35 ° C., and then an aqueous solution containing 4.1 g of KI 200 was added over 5 minutes.
g was added at an equal flow rate.

To this emulsion, 1.1 g of (CK-1) was added, precipitated, washed with water, desalted, and then added with 6 g of lime-processed gelatin to dissolve, and a 3.5% aqueous solution of (ATR-3) 1. The pH was adjusted to 6.2 by adding 5 cc. 550 g of a monodisperse silver iodobromide emulsion (EB-1) having an average grain size of 0.35 μm and a coefficient of variation of 15% was prepared.

Liquid I AgNO ₃ 40 g Distilled water 300 cc Liquid II KBr 36.4 g Distilled water 300 cc III Liquid AgNO ₃ 80 g Distilled water 300 cc IV Liquid KBr 72.8 g Distilled water 550 cc

Preparation of silver halide emulsion (EG-1) 24 g of lime-processed inert gelatin was added to distilled water, and
After dissolving at 0 ° C. for 1 hour, 1 g of KBr was added, and 1
The pH was adjusted to 3.2 by adding N-sulfuric acid.

After 10 mg of (AGS-1) was added to this solution, solutions I and II were added simultaneously at 75 ° C. over 15 minutes. After the addition was completed, the pH was adjusted to 6.0 with 1N NaOH and KBr was added to adjust the pAg to 9.4, (AZ-1)
2.5 mg and (AZ-2) 3.3 mg were added and the mixture was aged at 75 ° C. for 60 minutes. After the aging, 480 mg of (SG-1) was added, and 20 minutes after the addition, the temperature was raised to 35 ° C., and 200 g of an aqueous solution containing 4.1 g of KI was added at an equal flow rate over 5 minutes.

To this emulsion, 1.1 g of (CK-1) was added, precipitated, washed with water, desalted, and then added with 6 g of lime-processed gelatin to dissolve, and a 3.5% aqueous solution of (ATR-3) was added. The pH was adjusted to 6.2 by adding 5 cc. 550 g of a monodisperse silver iodobromide emulsion (EG-1) having an average grain size of 0.20 μm and a coefficient of variation of 19% was prepared.

Solution I AgNO ₃ 80 g Distilled water 600 cc Solution II KBr 72.8 g Distilled water 600 cc

Preparation of Silver Halide Emulsion (ER-1) 24 g of deionized gelatin was added to distilled water and the mixture was mixed at 40 ° C. for 1 hour.
After dissolution over time, 1 g of KBr was added, and 1N sulfuric acid was added thereto to adjust the pH to 3.2.

After 10 mg of (AGS-1) was added to this solution, solutions I and II were added simultaneously at 75 ° C. over 15 minutes. After the addition was completed, the pH was adjusted to 6.0 with 1N NaOH and KBr was added to adjust the pAg to 9.4, (AZ-1)
5.0 mg and 6.5 mg of (AZ-2) were added and the mixture was aged at 75 ° C. for 60 minutes. After aging (SR-1) 120mg, (SR
-6) 120 mg and (SR-2) 300 mg were added, and the temperature was brought to 35 ° C. 20 minutes after the addition, and then 200 g of an aqueous solution containing 4.1 g of KI was added at an equal flow rate over 5 minutes.

1.1 g of (CK-1) was added to this emulsion, precipitated, washed with water for desalting, and then 6 g of deionized gelatin was added to dissolve, and a 3.5% aqueous solution of (ATR-3) was added. The pH was adjusted to 6.2 by adding 5 cc. 550 g of a monodisperse silver iodobromide emulsion (ER-1) having an average grain size of 0.21 μm and a coefficient of variation of 20% was prepared.

Solution I AgNO ₃ 80 g Distilled water 600 cc Solution II KBr 72.8 g Distilled water 600 cc

[0111]

[Chemical formula 12]

[0112]

[Chemical 13]

(CK-1) Poly (isobutylene-co-
Monosodium maleate)

Preparation of Solid Dispersion (KB-1) 5.4 of lime-processed gelatin in a 300 ml dispersion container.
% Aqueous solution 110 g, polyethylene glycol (average molecular weight 2000) 5% aqueous solution 20 g, base precursor (BG-1) 70 g, and glass beads 200 ml with a diameter of 0.5 to 0.75 mm are added, and 300 using a Dynomill.
Disperse at 0 rpm for 30 minutes, adjust the pH to 6.5 with 2N sulfuric acid and adjust the base precursor (BG
A solid dispersion (KB-1) of -1) was obtained.

[0115]

[Chemical 14]

Preparation of Pigment Dispersion (GY-1) To 255 g of the polymerizable compound (MN-1), 45 g of Chromofine Yellow 5900 (trade name, manufactured by Dainichiseika Seiki Co., Ltd.) was mixed, and an Eiger Motor Mill (Eiger. (Manufactured by Engineering Co., Ltd.) was stirred at 5000 rpm for 1 hour to obtain a dispersion (GY-1). Polymerizable compound (MN-1) Compound described in Synthesis Example 1 of JP-A-64-68339 (manufactured by Nippon Kayaku Co., Ltd.)

Preparation of Pigment Dispersion (GM-1) Rubin F6B was added to 270 g of the polymerizable compound (MN-1).
(Product name, manufactured by Hoechst Co., Ltd.) 30 g was mixed and stirred for 1 hour at 5000 rpm using an Eiger Motor Mill (manufactured by Eiger Engineering Co.) to obtain a dispersion (GM-
1) was obtained.

Preparation of Pigment Dispersion (GC-1) Polymerizable compound (MN-1) (255 g), copper phthalocyanine (CI Pigment 15) (45 g) and Solsperse 500 were prepared.
0 (manufactured by ICI) 1.13 g, Sols Perth 24000
3.37 g (manufactured by ICI) was mixed and stirred for 1 hour at 5000 rpm using an Eiger motor mill (manufactured by Eiger Engineering) to obtain a dispersion (GC-1).

Preparation of Photosensitive Composition (PB-1) 45 g of pigment dispersion (GY-1) was added with (SV of (1P-4)).
-1) 9 g of 10% (wt%) solution, (RD-1) 2.
3 g, (RD-3) 3.1 g, (FF-3) (SV-
1) 2 g of 0.5% (wt%) solution and (ST-1)
0.5 g was added and dissolved to prepare an oily solution. To this solution, 7.6 g of silver halide emulsion (EB-1) and 24 g of solid dispersion (KB-1) were added, and the mixture was stirred at 10,000 rpm for 5 minutes using a 40φ dissolver while maintaining the temperature at 60 ° C. Then, a W / O emulsion photosensitive composition (PB-1) was obtained.

Preparation of Photosensitive Composition (PG-1) 45 g of pigment dispersion (GM-1) was added to (SV) of (1P-4).
-1) 9 g of 10% (wt%) solution, (RD-1) 2.
3 g, (RD-3) 3.1 g, (FF-3) (SV-
1) 2 g of 0.5% (wt%) solution and (ST-1)
0.5 g was added and dissolved to prepare an oily solution. To this solution, 7.6 g of silver halide emulsion (EG-1) and 24 g of solid dispersion (KB-1) were added, and the mixture was stirred at 10,000 rpm for 5 minutes using a 40φ dissolver while maintaining the temperature at 60 ° C. , W / O emulsion photosensitive composition (P
G-1) was obtained.

Preparation of Photosensitive Composition (PR-1) 45 g of pigment dispersion (GC-1) was added with (S) of (1P-4).
V-1) 9 g of 10% (wt%) solution, (RD-1)
2.3 g, (RD-2) 3.1 g, (FF-3) (S
V-1) 2 g of 0.5% (wt%) solution and (ST-
1) 0.5 g was added and dissolved to prepare an oily solution.

A silver halide emulsion (ER-1) was added to this solution.
7.6 g and 24 g of solid dispersion (KB-1) were added, and 5
While maintaining the temperature at 0 ° C., the mixture was stirred at 10000 rpm for 5 minutes using a 40φ dissolver to obtain a photosensitive composition (PR-1) as a W / O emulsion.

[0123]

[Chemical 15]

[0124]

[Chemical 16]

[0125]

[Chemical 17]

Photosensitive microcapsule dispersion (CB-
Preparation of 1) 48 g of water was added to 2 g of a 10% aqueous solution of the polymer (P-7) which is the copolymer of the present invention, and the mixed solution was added to 2N.
The pH was adjusted to 5.0 with sulfuric acid. Polymer (2P-
50 g of a 10% aqueous solution of 2) was added and mixed at 60 ° C. for 30 minutes. This mixed liquid was added to the above-mentioned photosensitive composition (PB-1), and a 40φ dissolver was used at 60 ° C. for 600 minutes per minute.
The mixture was stirred at 0 rotation for 20 minutes to obtain an emulsion in the state of W / O / W emulsion. Separately, melamine 31.5 g, formaldehyde 37% aqueous solution 52.2 g and water 170.
3 g was added, and the mixture was heated to 60 ° C. and stirred for 30 minutes to obtain a transparent aqueous solution of melamine-formaldehyde initial condensation product.

25 g of this initial condensate was added to the emulsion in the W / O / W emulsion state cooled to 40 ° C.,
The pH was adjusted to 5.0 with 2N sulfuric acid while stirring at 1200 rpm with a propeller blade. Next, the temperature of this liquid was raised to 70 ° C. in 30 minutes, and further stirred for 30 minutes. To this, add 10.3 g of 40% aqueous solution of urea and add 2N sulfuric acid.
The pH was adjusted to 3.5 and stirring was continued at 70 ° C. for another 40 minutes. After cooling this liquid to 40 ° C., 3 of κ-carrageenan
% Aqueous solution (9 g) was added, the mixture was stirred for 10 minutes, and the pH was adjusted to 6.5 with a 2N aqueous sodium hydroxide solution to prepare a photosensitive microcapsule dispersion (CB-1).

Photosensitive microcapsule dispersion (CG-
1) and Preparation of (CR-1) 38 g of water was added to 2 g of a 10% aqueous solution of the polymer (P-7), and the mixed solution was adjusted to pH 5.0 with 2N sulfuric acid. To this solution, 60 g of a 10% aqueous solution of polymer (2P-2) was added, and mixed at 60 ° C for 30 minutes. The photosensitive composition (PG-1) was added to this mixed solution, and the mixture was stirred at 60 ° C. for 20 minutes at 6000 rpm using a 40φ dissolver, and W /
An emulsion in the form of an O / W emulsion was obtained. Then (C
A photosensitive microcapsule dispersion (CG-1) was prepared by using a melamine-formaldehyde initial condensate as in B-1).

Then, in the preparation of (CB-1), (P
A photosensitive microcapsule dispersion (CR-1) was prepared in the same manner except that (PR-1) was used instead of B-1). Polymer (P-7) Poly (potassium vinylbenzenesulfinate-co-acrylamide-potassium co-vinylbenzenesulfonate Polymer (2P-2) Polyvinylpyrrolidone K-9
0 Polymer (PC-3) PVA KL318 (Kuraray, carboxy-modified PVA)

Preparation of High Boiling Organic Compound Dispersion (HB-1) 50 g of a 10% aqueous solution of polymer (PC-3) kept at 60 ° C. was mixed with 15 g of a 5% aqueous solution of sodium dodecylbenzene sulfonate, and MN was added. -1 (50 g) was added and the mixture was dispersed with a homogenizer (manufactured by Nippon Seiki Co., Ltd.) at 8000 rpm for 10 minutes.

Preparation of High Boiling Organic Compound Capsule (HC-1) As high boiling organic compound (MN-1) 45 g, (1P
-1) (SV-1) 10% (wt%) solution 9 g,
(RD-1) 1.6 g, (RD-2) 1.2 g, (FF
2 g of (SV-1) 0.5% (wt%) solution of 3) was added and dissolved to prepare an oily solution (YU-1). 36 g of water was added to 4 g of a 15% aqueous solution of the polymer (2P-4), and the mixed solution was adjusted to pH 5.0 with 2N sulfuric acid. To this solution, 60 g of a 10% aqueous solution of polymer (2P-2) was added, and mixed at 60 ° C for 30 minutes. The oily solution composition (YU-1) was added to this mixed solution, and the mixture was stirred at 60 ° C. at 6000 rpm for 20 minutes using a 40φ dissolver to obtain an emulsion in the form of an emulsion. Then, in the same manner as in the preparation of the photosensitive microcapsule dispersion (CB-1), melamine-
A high boiling organic compound capsule dispersion (HC-1) was prepared using the formaldehyde initial condensate.

Preparation of Photosensitive Material 101 Photosensitive microcapsule (CB-1) of the present invention
g, 15 g of (CG-1) and 15 g of (CR-1) were taken out, respectively, heated to 40 ° C. without stirring and dissolved, and then mixed, to prepare a 5% aqueous solution of a surfactant (WW-1). 6.5
g, 8 g of 1% aqueous solution of surfactant (WW-2), (HB
-1) 7.5 g of the dispersion and 7.5 g of the (HC-1) dispersion and 15 cc of water were added, and they were mixed by stirring at 40 ° C for 10 minutes. This solution was filtered through a 44 μm mesh filter cloth to prepare a capsule coating solution 101.

[0133]

[Chemical 18]

This coating solution was applied to the aluminum vapor deposition surface of a support obtained by vapor deposition of aluminum on a polyethylene terephthalate film having a thickness of 12 μm by an extrusion method so that the coating amount was 100 cc / m ^2, and dried at 60 ° C. The photosensitive material 101 was prepared by winding the coated surface inside at 25 ° C. and 65%.

Example 2 Preparation of Photosensitive Microcapsule Dispersion Liquid (CB-2) In the preparation of (CB-1), (P-11) was used instead of (P-7) as the copolymer polymer of the present invention. A photosensitive microcapsule dispersion (CB-
2) was adjusted. Photosensitive microcapsule dispersion (CG-2) and (C
Preparation of R-2) Preparation of (CG-1) and (CR-1) (P-7)
In the same manner except that (P-11) is used instead of (P-11), the photosensitive microcapsule dispersion liquid (CG-2) and (CR-
2) was adjusted. Preparation of photosensitive material 102 In preparation of photosensitive material 101, (CB-1), (CG-
1) and (CR-1) instead of (CB-2), (C
G-2) and (CR-2) were used, and the photosensitive material 102 was prepared in the same manner.

Example 3 Preparation of Photosensitive Microcapsule Dispersion Liquid (CB-3) In preparation of (CB-1), (P-13) was used in place of (P-7) as the copolymer polymer of the present invention. A photosensitive microcapsule dispersion (CB-
2) was adjusted. Photosensitive microcapsule dispersion (CG-3) and (C
Preparation of R-3) In preparation of (CG-1) and (CR-1) (P-7)
In the same manner except that (P-13) is used instead of (P-13), the photosensitive microcapsule dispersion liquid (CG-3) and (CR-
3) was adjusted. Preparation of photosensitive material 103 (CB-1), (CG-
1) and (CR-1) instead of (CB-3), (C
G-3) and (CR-3) were used, and the light-sensitive material 103 was prepared in the same manner.

Comparative Example 1 Preparation of Photosensitive Microcapsule Dispersion Liquid (CB-4) In preparation of (CB-1), the following (2P-5) was used instead of (P-7) of the copolymer polymer of the present invention. In the same manner as above except that the photosensitive microcapsule dispersion liquid (CB-
4) was adjusted. Photosensitive microcapsule dispersion (CG-4) and (C
Preparation of R-4) In preparation of (CG-1) and (CR-1) (P-7)
In the same manner except that (2P-5) is used instead of (2P-5).
4) was adjusted. (2P-5) Poly (vinylbenzenesulfinate potassium-co-methylmethacrylate) Preparation of photosensitive material 104 In preparing photosensitive material 101, (CB-1), (CG-
1) and (CR-1) instead of (CB-4), (C
The photosensitive material 104 was prepared in the same manner except that G-4) and (CR-4) were used.

Comparative Example 2 Preparation of Photosensitive Microcapsule Dispersion Liquid (CB-5) In preparation of (CB-1), the following (2P-6) was used instead of (P-7) of the copolymer polymer of the present invention. In the same manner as above except that the photosensitive microcapsule dispersion liquid (CB-
5) was adjusted. Photosensitive microcapsule dispersion (CG-5) and (C
Preparation of R-5) In preparation of (CG-1) and (CR-1) (P-7)
In the same manner except that (2P-6) is used instead of (2P-6), photosensitive microcapsule dispersions (CG-5), (CR-5)
Was adjusted. (2P-6) Poly (potassium benzenesulfinate-co-potassium co-benzenesulfinate) Preparation of photosensitive material 105 In preparation of photosensitive material 101, (CB-1), (CG-
1) and (CR-1) instead of (CB-5), (C
G-5) and (CR-5) were used, and the light-sensitive material 105 was prepared in the same manner.

Comparative Example 3 Preparation of Photosensitive Microcapsule Dispersion Liquid (CB-6) In the preparation of (CB-1), (P) of the copolymer of the present invention was used.
A photosensitive microcapsule dispersion liquid (CB-6) was prepared in the same manner except that the following (2P-7) was used instead of -7). Photosensitive microcapsule dispersion (CG-6) and (C
Preparation of R-3) In preparation of (CG-1) and (CR-1) (P-7)
In the same manner except that (2P-7) is used instead of (2P-7), photosensitive microcapsule dispersions (CG-6), (CR-6)
Was adjusted. (2P-7) Polybenzene potassium sulfinate

Preparation of photosensitive material 106 In preparing photosensitive material 101, (CB-1), (CG-
1) and (CR-1) instead of (CB-6), (C
The photosensitive material 106 was prepared in the same manner except that G-6) and (CR-6) were used.

[0141]

[Table 1]

Evaluation of Emulsified Dispersion (w / o / w Emulsion) and Capsule Average Particle Size As shown in Table 1, Examples 1, 2, 3 and Comparative Examples 2, 3
In Comparative Example 1, there is a deviation between the emulsified dispersion and the average particle size of the capsules. Thus, it can be seen that the dissociative group greatly contributes to the stabilization of emulsion particles.

Image evaluation Preparation of image receiving material (RS-1) Surfactant (Poise 520, manufactured by Kao Corporation) 5.6 g,
After stirring and mixing 354.4 ml of water and 354.4 ml of water, dispersion was performed at 8000 rpm for 3 minutes using a disperser (trade name: Ultra Disperser (LK-41 type), manufactured by Yamato Scientific Co., Ltd.). 52 g of this dispersion was mixed with 40 g of a 10% aqueous solution of polyvinyl alcohol (PVA-117, manufactured by Kuraray Co., Ltd.), and a 1% aqueous solution of a surfactant (WW-3) 4
ml and water (22 ml) were added to prepare a coating solution for forming an image receiving layer.

This coating solution was weighed 80 g / m ^{2 on} a paper support (as a fiber length distribution defined by JIS-P-8207, the sum of the weight% of the 24 mesh residue and the weight% of the 42 mesh residue was 30). A paper support having a fiber length distribution such that the fiber length distribution is from 60 to 60% [JP-A-63-18623]
No. 9)]) was uniformly coated on the surface of the plate at 65 g / m ² and then dried at 60 ° C. to prepare an image receiving material (RS-1).

[0145]

[Chemical 19]

Image formation Using a halogen lamp adjusted to a color temperature of 3100 ° K,
A black silver image was continuously exposed through a wedge having a transmission density varying from 0 to 4.0 under exposure conditions of 5000 lux and 1 second. Immediately after the exposure, the side opposite to the coated surface of the light-sensitive material was brought into close contact with a drum heated to 150 ° C. and heat-developed for 1.0 second. After 8 seconds, the image receiving material (RS-
1) and the coated surface are overlaid and passed through a pressure roller with a diameter of 3 cm and a pressure of 200 kg / cm ² (surface temperature of 65 ° C) at a speed of 3.2 cm / sec, and the image receiving material is peeled off from the photosensitive material immediately after passing. did.

[0147]

[Table 2]

As shown in Table 2, the photosensitive materials 105 and 106
The images obtained with the light-sensitive materials 101, 102, 103, and 104 had a very low minimum density portion, and a very excellent image without spot-like color development was obtained.

Example 4 Preparation of Photosensitive Composition (PB-2) 45 g of pigment dispersion (GY-1) was added with (SV of (1P-4).
-1) 9 g of 10% (wt%) solution, (RD-3) 3.
1 g, (FF-3) (SV-1) 0.5% (wt%)
2 g of the solution and 0.5 g of (ST-1) were added and dissolved to prepare an oily solution. 7.6 g of silver halide emulsion (EB-1) and 24 g of solid dispersion (KB-1) were added to this solution.
g, and while maintaining the temperature at 60 ° C., using a 40φ dissolver, stirring at 10000 rpm for 5 minutes, and W / O
An emulsion photosensitive composition (PB-2) was obtained.

Photosensitive microcapsule dispersion (CB-
Preparation of 7) 10 of the polymer (P-7) of the copolymer polymer of the present invention
48 g of water was added to 2 g of 2% aqueous solution, and the mixed solution was adjusted to pH 5.0 with 2N sulfuric acid. Polymer (2P-2) in this liquid
50 g of a 10% aqueous solution of was added and mixed at 60 ° C. for 30 minutes. This mixed solution was added to the above-mentioned photosensitive composition (PB-2), and a 40φ dissolver was used at 60 ° C. for 6000 minutes per minute.
The mixture was stirred for 20 minutes by rotation to obtain an emulsion in the state of W / O / W emulsion. Separately, melamine 31.5 g, formaldehyde 37% aqueous solution 52.2 g and water 170.3
g, heated to 60 ° C., and stirred for 30 minutes to obtain a transparent aqueous solution of the melamine-formaldehyde initial condensation product.

25 g of this initial condensate was added to the emulsion in the W / O / W emulsion state cooled to 40 ° C.,
The pH was adjusted to 5.0 with 2N sulfuric acid while stirring at 1200 rpm with a propeller blade. Next, the temperature of this liquid was raised to 70 ° C. in 30 minutes, and further stirred for 30 minutes. To this, add 10.3 g of 40% aqueous solution of urea and add 2N sulfuric acid.
The pH was adjusted to 3.5 and stirring was continued at 70 ° C. for another 40 minutes. After cooling this liquid to 40 ° C., 3 of κ-carrageenan
% Aqueous solution (9 g) was added, the mixture was stirred for 10 minutes, and the pH was adjusted to 6.5 using a 2N aqueous sodium hydroxide solution to prepare a photosensitive microcapsule dispersion (CB-7).

Preparation of Reducing Agent Solid Dispersion (KB-2) 181 g 1% aqueous solution of lime-processed gelatin in 300 ml dispersion container 1% aqueous solution of surfactant (WW-2) 1
8.8 cc, reducing agent (RD-1) 30.2 g and 200 ml of glass beads having a diameter of 0.5-0.75 mm were added, and the mixture was dispersed for 20 minutes at 2000 rpm using a Dynomill.
A reducing agent solid dispersion (KB-2) was prepared.

Preparation of Photosensitive Material 107 45 g of the photosensitive microcapsules (CB-7) of the present invention
Were taken out, each was heated to 40 ° C. without stirring, dissolved and then mixed, and a 5% aqueous solution of a surfactant (WW-1) was added.
5 g, 8 g of 1% aqueous solution of surfactant (WW-2), (K
B-2) Add 3.5 g of the dispersion and 15 cc of water, and add 40 ° C.
Stir for 10 minutes to mix. This solution was filtered through a 44 μm mesh filter cloth to prepare a capsule coating solution 107.

This coating solution was applied to the aluminum vapor deposition surface of a support obtained by vapor deposition of aluminum on a polyethylene terephthalate film having a thickness of 12 μm by an extrusion method so that the coating amount was 100 cc / m ² and dried at 60 ° C. The photosensitive material 107 was prepared by winding the coated surface inside at 25 ° C. and 65%.

Comparative Example 4 Preparation of Photosensitive Microcapsule Dispersion Liquid (CB-8) In preparation of (CB-5), (2P-5) was used in place of (P-7) of the copolymer polymer of the present invention. Photosensitive Microcapsule Dispersion Liquid (CB-8)
Was adjusted. Preparation of Photosensitive Material 108 Photosensitive Material 108 was prepared in the same manner except that (CB-8) was used instead of (CB-7) in the preparation of Photosensitive Material 107.
Was adjusted.

Comparative Example 5 Preparation of Photosensitive Microcapsule Dispersion Liquid (CB-9) In preparation of (CB-7), (2P-6) was used in place of (P-7) of the copolymer polymer of the present invention. Photosensitive Microcapsule Dispersion Liquid (CB-9)
Was adjusted. Preparation of photosensitive material 109 In preparation of photosensitive material 107, photosensitive material 109 was prepared in the same manner except that (CB-9) was used instead of (CB-7).
Was adjusted.

Comparative Example 6 Preparation of Photosensitive Microcapsule Dispersion Liquid (CB-10) In preparation of (CB-7), (2P-7) was used instead of (P-7) of the copolymer polymer of the present invention. A photosensitive microcapsule dispersion (CB-1
0) was adjusted. Preparation of photosensitive material 110 In preparation of photosensitive material 107, photosensitive material 11 was prepared in the same manner except that (CB-10) was used instead of (CB-7).
0 was adjusted.

Image formation Using a halogen lamp adjusted to a color temperature of 3100 ° K,
A black silver image was continuously exposed through a wedge having a transmission density varying from 0 to 4.0 under exposure conditions of 5000 lux and 1 second. Immediately after the exposure, the side opposite to the coated surface of the light-sensitive material was brought into close contact with a drum heated to 150 ° C. and heat-developed for 1.0 second. After 8 seconds, the image receiving material (RS-
1) and the coated surface are overlaid and passed through a pressure roller with a diameter of 3 cm and a pressure of 200 kg / cm ² (surface temperature of 65 ° C) at a speed of 3.2 cm / sec, and the image receiving material is peeled off from the photosensitive material immediately after passing. did. A positive image is obtained on the transferred image receiving paper, and X
Table 3 shows the results of the concentration measurement with -lite310.

[0159]

[Table 3]

In this case, the coloring of the image receiving material occurs when the polymerizable compound in the microcapsules is not polymerized. Therefore, in the case of the above evaluation method, when the denseness of the capsules is high, the reducing agent present in the binder does not enter the microcapsules, so polymerization does not occur and after transfer, a high density is given on the image receiving paper, On the other hand, when the compactness is low, the polymerization proceeds and the coloration on the image receiving paper is low.

Example 5 Preparation of Photosensitive Materials 111, 112, 113, and 114 In preparing Photosensitive Materials 101, 104, 105, and 106, a high-boiling organic compound dispersion (HB-1) (HC-
Photosensitive materials 111, 112, 113, and 114 were prepared in the same manner except that 1) water was added instead of 1).
Each of them was cut to a size of 2.6 cm x 10 cm, overlapped with plain paper of the same area, and a load of 500 kg / m ² was applied from the top and left for 1 day. Each of these plain papers was placed in 10 ml of methanol and then left to stand for 15 minutes. When these liquids were analyzed by liquid chromatography after filtration, 11
1,112 is 5% or less of the coating amount of the monomer, 113,1
Approximately 30% was detected in 14. Therefore, it can be said that the microcapsule of the present invention has a stable particle size and is excellent in the retention of the core substance.

Claims (3)

[Claims] 1. A repeating unit having a sulfinic acid group,
A core substance containing at least a polymerizable compound is dispersed in the form of an oil droplet in an aqueous medium containing a copolymer of a repeating unit having active hydrogen and a repeating unit having an anionic dissociative group, and the core surrounding the oil droplet is dispersed. A method for preparing a microcapsule in which a resin wall made of an aminoaldehyde resin is formed on a substrate. 2. The method for preparing microcapsules according to claim 1, wherein the core substance containing a polymerizable compound contains silver halide and a reducing agent. 3. A photosensitive material comprising a support and microcapsules prepared by the method for preparing microcapsules according to claim 2 and a binder.