JPH06167765A - Photo image forming material - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a photo-image forming material capable of forming a good image on both sides by preventing a show-through phenomenon when it is used as a double-sided photo-image forming material. [Structure] A photoimage-forming material comprising a support and a photoimage-forming layer containing a reducing agent on both the front surface and the back surface of a microcapsule containing both a leuco dye capable of oxidative coloring and a photo-oxidizing agent. And the light transmittance of the support is 400 to 4
A photoimage forming material which is 3% or less in a region of 50 nm and 1% or less in a region of 400 nm or less.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a photoimageable material, and more particularly to a heat-fixable photoimageable material which can be used for proof paper, printout paper and the like.

[0002]

2. Description of the Related Art Conventionally, as one of non-silver salt light-sensitive materials, a photo-image forming material (so-called free radical photography) is known in which a light-sensitive portion is visualized when imagewise exposed. In this case, a technique of radical-oxidizing and coloring various leuco dyes with a photo-oxidizing agent is applied to form dyes image-wise corresponding to an optical image to form a colored image (for example, Pho
to. Sci. Eng. , 5, 98-103 (196
1), JP-B-43-29,407, JP-A-55-55
335, JP-A-57-60,329 and JP-A-62.
The details are reported in Japanese Patent Publication No. 66,254. ).

However, in such a photoimage forming material, when a dye is formed by exposure to form an image and then the photoimage forming material is exposed to room light, sunlight or white light, it remains. Since the photo-oxidizing agent oxidizes the leuco dye to cause a pigment forming reaction, there is a drawback that it is difficult to handle in a bright room. In order to solve such a drawback, for example, the original image is preserved by impregnating the photoimageable material after forming the image with a reducing agent solution which acts as a free radical scavenger (hydroquinone etc.) by spray coating or the like. It is known that However, such a method for fixing an original image has a drawback in that although the dry development is realized, the same operations and operations as those in the wet development are added again, which complicates the whole process. It was

On the other hand, for example, DuPont (Du P
A feature such as Dylux (registered trademark) manufactured by ONT Co., Ltd. that does not require a wet process such as performing image formation with ultraviolet rays and then activating and fixing the photoreducing substance with visible light. Photoimageable materials having are also commercially available. However, this method has the drawbacks that the exposure device is used for a long time because the light is used twice, and the processing speed is slowed down due to the need to replace the spectral filter.

Further, in Japanese Patent Publication No. 43-29,407, a leuco dye and a photo-oxidizing agent are contained together with a reducing thermal fixing agent in a binder solution, or the fixing agent is overcoated on a photosensitive layer. By doing so, there is a description that heat fixing is performed after image exposure. However, this method has a drawback that it is not practical because the light-sensitive material (leuco dye and photo-oxidizing agent) and the fixing agent coexist in close proximity to each other, resulting in deterioration of sensitivity over time.

On the other hand, the photoimage-forming material comprising these leuco dyes and photo-oxidizing agents is usually uniformly dissolved in an organic solvent and applied (or dipped or cast) on a support such as paper or plastic film. It is produced by removing the solvent by evaporation by drying. Therefore, it is necessary to take explosion-proof measures such as manufacturing facilities associated with the use of such a volatile solvent, which is disadvantageous in terms of both safety and manufacturing cost.

In order to solve various drawbacks as described above,
The present inventors have prepared microcapsules containing at least one leuco dye capable of oxidative coloring and at least one photo-oxidizing agent, as well as dissolving at least one reducing agent in an insoluble or sparingly soluble organic solvent in water. We have already proposed a photo-image forming material obtained by coating and drying a coating solution containing an emulsified dispersion on a support. By the way, for a document having images recorded on both sides, it is convenient to use a photoimage forming material having a photoimage forming layer on both sides of a support (referred to as a double-sided photoimage forming material).

[0008]

However, when the conventional double-sided photoimageable material is used, the phenomenon of show-through appears because the light at the time of exposing the front surface reaches the back surface. When an image is formed on the back surface, there is a drawback that the image on the front surface and the image on the back surface overlap each other, making it difficult to see the formed image.

[0009] Therefore, as a result of intensive studies made by the present inventors in order to solve the above-mentioned drawbacks, as a result, it is possible to prevent the show-through phenomenon by using a support having a light transmittance of 450 nm or less of a certain amount or less. The inventors have found that the above can be achieved and reached the present invention. Therefore, it is an object of the present invention to provide a double-sided photoimageable material capable of preventing the show-through phenomenon and forming good images on both sides.

[0010]

The above objects of the present invention are as follows.
A photoimage forming material comprising a photoimage forming layer containing microcapsules and a reducing agent, both of which include an oxidatively colorable leuco dye and a photooxidant, on the front and back surfaces of the support, The light transmittance of the support is 400 to 450 nm.
3% or less in the region of 1 and 1% or less in the region of 400 nm or less.

The light transmittance of the support used in the photoimageable material of the present invention is preferably 1% or less in the region of 400 to 450 nm and 0.5% or less in the region of 400 nm or less. . When the light transmittance is 3% or more in the region of 400 to 450 nm or 1% or more in the region of 400 nm or less, the show-through phenomenon cannot be effectively prevented.

The above-mentioned adjustment of the light transmittance of the support can be easily carried out by incorporating in the support a light absorber such as an ultraviolet absorber which absorbs light having a wavelength of 450 nm or less. it can. These light absorbers may be used alone or in combination of two or more kinds. The amount to be contained is appropriately adjusted according to the light transmittance. Examples of the light absorber include known dyes or pigments that absorb ultraviolet rays.

As the ultraviolet absorber, known ultraviolet absorbers can be used, and specific examples thereof include pt-
Butylphenyl salicylate, 2,4-dihydroxybenzophenone, 2-hydroxy-4-n-octoxy-
Examples thereof include benzophenone, 2-hydroxy-4-methoxybenzophenone, 2 (2'-hydroxy4'-n-octoxyphenyl) benzotriazole, and 2- (2'-hydroxy-5'-methyl-phenyl) benzotriazole. .

The leuco dye which can be used in the present invention has one or two hydrogen atoms which form a dye by adding an electron or removing an electron to form a dye. Means a reduced dye. In the present invention, by selecting one of such leuco dyes that is substantially colorless or light-colored, it is possible to form an image in which a white background is colored by photooxidation.

The leuco dye used in the present invention is (1) aminotriarylmethane, (2) aminoxanthene, (3) aminothioxanthene as described in, for example, US Pat. No. 3,445,234. , (4) amino-9,10-dihydroacridine, (5) aminophenoxazine, (6) aminophenothiazine, (7) aminodihydrophenazine, (8) aminodiphenylmethane,
(9) Leuco damine, (10) aminohydrocinnamic acid (cyanoethane, leucomethine), (11) hydrazine, (12) leucoin digoid dye, (13)
Amino-2,3-dihydroanthraquinone, (14) tetrahalo-p, p'-biphenol, (15) 2- (p
-Hydroxyphenyl) -4,5-diphenylimidazole, (16) phenethylaniline and the like can be mentioned. Among these leuco dyes, those of (1) to (9) lose their one hydrogen atom to form a color and become dyes, while those of (10) to (16) lose two hydrogen atoms. Form a dye.

Specific examples of such leuco dyes include:
Tris (4-dimethylaminophenyl) methane, tris (4-diethylaminophenyl) methane, bis (4-diethylaminophenyl)-(4-diethylamino-2-
Methylphenyl) methane, bis (4-diethylamino-)
2-Methylphenyl)-(4-diethylaminophenyl) methane, bis (1-ethyl-2-methylindol-3-yl) -phenylmethane, 2-N- (3-trifluoromethylphenyl) -N-ethylamino -6-Diethylamino-9- (2-methoxycarbonylphenyl)
Xanthene, 2- (2-chlorophenyl) amino-6-
Dibutylamino-9- (2-methoxycarbonylphenyl) xanthene, 2-dibenzylamino-6-diethylamino-9- (2-methoxycarbonylphenyl) xanthene, benzo [a] -6-N, N-diethylamino-
9-2-methoxycarbonylphenyl) xanthene, 2
-(2-chlorophenyl) -amino-6-dibutylamino-9- (2-methylphenylcarboxamidophenyl) xanthene, 3,6-dimethoxy-9- (2-methoxycarbonyl) -phenylxanthene, benzoylleucomethylene blue, 3 , 7-bis-diethylaminophenoxazine and the like.

The photo-oxidizing agent used in the present invention is visible light,
It is activated by actinic rays such as ultraviolet rays, infrared rays and X-rays and reacts with the leuco dye to form a colored image on the background of the unexposed portion. Photooxidants that can be used in the present invention have different peak sensitivities across the spectrum, depending on the structure of the compound. That is, by being exposed to a specific actinic ray, the photo-oxidizing agent contained in the microcapsules is activated, and the leuco dye contained in the microcapsules is oxidized to form a color, and the light-irradiated portion A colored image is formed on.

Specific examples of such photo-oxidizing agents include lophine such as 2,4,5-triarylimidazole dimer described in JP-B-62-39,728 and 63-2099. Dimer compounds, azide compounds such as 2-azidobenzoxazole, benzoyl azide and 2-azidobenzimidazole described in US Pat. No. 3,282,693, US Pat.
No. 568, 3'-ethyl-1-methoxy-2
-Pyridothiacyanine perchlorate, 1-methoxy-
Pyridinium compounds such as 2-methylpyridinium-p-toluenesulfonate, N-bromocinnimide, tribromomethylphenyl sulfone, 2-trichloromethyl-
5- (p-butoxystyryl) -1,3,4-oxadiazole, 2,6-ditrichlororetyl-4- (p-
Organohalogenated compounds such as methoxyphenyl) -triazine, azido polymers described in the abstract of the 1968 Spring Research Presentation of the Photographic Society of Japan, page 55, benzophenone,
Mention may be made of p-aminophenyl ketone, polynuclear quinones, thioxanthenones and mixtures thereof.

In the present invention, among the above compounds,
It is preferable to use a lophine dimer compound or an organic halogen compound, and it is particularly preferable to use these compounds in combination from the viewpoint of enhancing the sensitivity. In the present invention, the amount of the photo-oxidizing agent used with respect to the leuco dye is 1 in molar ratio
The range of 0: 1 to 1:10 is preferable, and the range of 2: 1 to 1: 2 is particularly preferable.

In the present invention, known stabilizers such as known sensitizers and antioxidants may be added to the microcapsules and used as additional components of the photo-oxidizing agent. Examples of antioxidants include phenol compounds, hydroquinone compounds, and catechol compounds. Specific examples of these compounds include 2,6, -di-
t-butyl-4-methylphenol, 2,4,6-tri-t-butylphenol, 2,5-di-t-butylhydroquinone, 2,3-di-t-butylhydroquinone,
2,5-di-t-octylhydroquinone, 2,5-di-t-amylhydroquinone, 3,6-di-t-butylcatechol and the like can be mentioned. The amount of the antioxidant used is preferably in the range of 0.001 to 2, and particularly preferably in the range of 0.01 to 0.1 with respect to the photo-oxidant 10 by weight ratio.

Regarding the antioxidants and the like, Japanese Patent Application No.
It is described in detail in JP-A No. 2-287096 (Please refer to Japanese Patent Laid-Open Publication No. Sho). With the photoimageable material of the present invention, after the imagewise irradiation of light to form a color image, the image can be made stable and reliable by heating, for example (referred to as image fixing). That is, when the image-forming photoimage forming material is heated, the microcapsules contained in the photoimage forming layer become substance-permeable, and the photo-oxidizing agent and the reducing agent separated by the microcapsules come into contact with each other, This is for deactivating the photo-oxidizing agent.

The reducing agent used in the present invention is a so-called free radical scavenger that traps the free radicals of the activated photo-oxidizing agent and has a function of deactivating the oxidizing action of the photo-oxidizing agent. is there. Therefore, the leuco dye is no longer oxidized by the photooxidant when the photoimageable material is irradiated with actinic radiation after heating. The above free radical scavenger can be appropriately selected and used from known compounds. Specifically, for example, US Pat.
No. 042,515 has a hydroxyl group on the benzene ring, and at least another hydroxyl group or an amino group is present at another position on the benzene ring (for example, hydroquinone, catechol, resorcinol,
Hydroxyhydroquinone, phloroglicinol and o-
Aminophenols, aminophenols such as p-aminophenol, etc.), cyclic phenylhydrazide compounds described in JP-B-62-39,728, guanidine derivatives, alkylenediamine derivatives, hydroxyamine derivatives, phenylhydrazine compounds and the like. To be

The above reducing agents may be used alone or in combination of two or more kinds. Further, any reducing substance capable of acting on the oxidizing agent can be used without being limited to the above reducing agents. The reducing agent can be used in the range of 1 to 100 mol per 1 mol of the photo-oxidizing agent, but 5
It is particularly preferred to use -20 mol. In addition, the fixing of the image of the present invention can be performed by applying pressure, or applying pressure or
It is also possible to destroy the microcapsules by heating.

In the present invention, the photooxidizing agent and the leuco dye are used from the viewpoint of improving the transparency of the photoimage forming layer and the raw storage stability (preventing fogging) such as preventing contact between the photooxidizing agent and the reducing agent at room temperature. Is encapsulated in a microcapsule, but the photo-oxidizing agent, the leuco dye, and the reducing agent may be separately encapsulated in a microcapsule before use. Any of interfacial polymerization method, internal polymerization method, and external polymerization method can be adopted for the production of the microcapsules used in the present invention, and particularly, a leuco dye and a photo-oxidizing agent (referred to as a photo-image forming substance). Alternatively, it is preferable to employ an emulsion polymerization method in which a core substance containing a reducing agent is emulsified in an aqueous solution in which a water-soluble polymer is dissolved, and then a wall of the polymer substance is formed around the oil droplets.

The reactant forming the polymer substance is added inside the oil droplet and / or outside the oil droplet. As the core substance containing the photoimage forming substance, a high-boiling point oil and a low-boiling point auxiliary solvent used for a reducing agent described later can be used. Specific examples of the polymer material include polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, melamine resin, polystyrene, styrene methacrylate copolymer,
Examples thereof include styrene-acrylate copolymer. Preferred polymeric substances are polyurethanes, polyureas, polyamides, polyesters and polycarbonates, particularly preferably polyurethanes and polyureas. Two or more polymer substances can be used in combination.

Specific examples of the water-soluble polymer include gelatin, polyvinylpyrrolidone, polyvinyl alcohol and the like. For example, when using polyurea as a capsule wall material, diisocyanate, triisocyanate, tetraisocyanate, polyisocyanate such as polyisocyanate prepolymer, and polyamine such as diamine, triamine, tetraamine, and two amino groups The microcapsule wall can be easily formed by reacting the prepolymer, piperazine or its derivative or the polyol, etc., contained above in an aqueous solvent by an interfacial polymerization method.

Further, for example, the composite wall made of polyurea and polyamide or the composite wall made of polyurethane and polyamide is added, for example, by using polyisocyanate and acid chloride or polyamine and polyol, after adjusting the pH of the emulsifying medium as the reaction liquid. It can be prepared by warming. For details of the method for producing a composite wall composed of these polyurea and polyamide, see JP-A-58-6.
6948. The average particle diameter of the microcapsules used in the present invention is 30 μm or less in terms of volume average diameter, especially 4 from the viewpoint of improving image resolution.
It is preferably μm or less.

Furthermore, a metal-containing dye, a charge control agent such as nigrosine, or any other additive substance can be added to the microcapsule wall used in the present invention, if necessary. These additive substances can be contained in the wall of the capsule at the time of forming the wall or at any time. or,
A monomer such as a vinyl monomer may be graft-polymerized, or these polymers may be attached in order to adjust the chargeability of the surface of the capsule wall as necessary.

Further, a solid sensitizer may be added to swell the microcapsule wall during heating. As the solid sensitizer, those which are solid at room temperature and have a melting point of 50 ° C. or higher, preferably 120 ° C. or lower, can be selected and used from among the plasticizers of polymers used for the microcapsule wall. For example, when the wall material is made of polyurea or polyurethane, a hydroxy compound, a carbamic acid ester compound, an aromatic alkoxy compound, an organic sulfonamide compound, an aliphatic amide compound, an arylamide compound and the like are preferably used.

In the present invention, the reducing agent may be used in a solid-dispersed state using a sand mill or the like.
After being dissolved in a water-insoluble or insoluble organic solvent, it may be mixed with an aqueous phase having a water-soluble polymer containing a surfactant as a protective colloid and used in the form of an emulsion-dispersed dispersion. preferable. The organic solvent used in this case can be appropriately selected from high boiling point oils.

Preferred oils include, in addition to esters, alkalinized naphthalenes such as dimethylnaphthalene, diethylnaphthalene, diisopropylnaphthalene, dimethylbiphenyl, diethylbiphenyl, diisopropylbiphenyl, diisobutylbiphenyl, 1-methyl-1-.
Dimethylphenyl-1-phenylmethane, 1-ethyl-
1-dimethylphenyl-1-phenylmethane, 1-propyl-1-dimethylphenyl-1-phenylmethane, triallylmethane (eg, tritoluylmethane, toluyldiphenylmethane), terphenyl compound (eg,
Terphenyl), alkyl compounds, alkylated diphenyl ethers (eg propyl diphenyl ether),
Examples include hydrogenated terphenyl (eg, hexahydroterphenyl), diphenyl ether, chlorinated paraffin, and the like. Among these, it is particularly preferable to use esters from the viewpoint of emulsion stability of the emulsified dispersion.

Examples of the esters include phosphates (eg, triphenyl phosphate, tricresyl phosphate, butyl phosphate, octyl phosphate, cresyl diphenyl phosphate), phthalates (dibutyl phthalate, 2-ethylhexyl phthalate, phthalic acid). Ethyl, octyl phthalate, butylbenzyl phthalate), tetrahydrophthalate dioctyl, benzoic acid ester (ethyl benzoate, propyl benzoate, butyl benzoate, isopentyl benzoate, benzyl benzoate), abietic acid ester (ethyl abietic acid, Benzyl abietic acid), dioctyl adipate, isodecyl succinate, dioctyl azelate, oxalate ester (dibutyl oxalate, dipentyl oxalate), diethyl malonate, maleate ester (dimethyl maleate, maleic acid) Diethyl acid, dibutyl maleate), tributyl citrate, sorbate (methyl sorbate, ethyl sorbate, butyl sorbate), sebacate (dibutyl sebacate, dioctyl sebacate), ethylene glycol esters (formic acid monoester) And diesters, butyric acid monoesters and diesters, lauric acid monoesters and diesters, palmitic acid monoesters and diesters, stearic acid monoesters and diesters, oleic acid monoesters and diesters), triacetin, diethyl carbonate, diphenyl carbonate, ethylene carbonate, carbonic acid propylene,
Examples thereof include boric acid esters (tributyl borate, tripentyl borate) and the like. Among these, the use of tricresyl phosphate alone or in combination is preferable because the reducing agent has particularly good emulsion dispersion stability. It is also possible to use the above oils in combination, or to use in combination with other oils.

In the present invention, an auxiliary solvent may be added to the above organic solvent as a dissolution aid having a low boiling point. As such an auxiliary solvent, for example, ethyl acetate, isopropyl acetate, butyl acetate, methylene chloride and the like can be mentioned as particularly preferable ones. The water-soluble polymer to be contained as a protective colloid in the aqueous phase mixed with the oil phase containing these components may be appropriately selected from known anionic polymers, nonionic polymers and amphoteric polymers. However, polyvinyl alcohol, gelatin, cellulose derivatives and the like are preferable.

As the surface active agent to be contained in the aqueous phase, an anionic or nonionic surface active agent which does not cause precipitation or aggregation by acting on the protective colloid may be appropriately selected and used. it can. Preferred surfactants include sodium alkylbenzene sulfonate, sodium alkylsulfate, dioctyl sodium sulfosuccinate, polyalkylene glycol (eg, polyoxyethylene nonylphenyl ether), and the like.

In the emulsified dispersion, the oil phase containing the above components and the aqueous phase containing the protective colloid and the surfactant are mixed using a means such as high speed stirring, ultrasonic dispersion or the like used for ordinary fine particle emulsification. It can be dispersed and easily obtained.
Also, the value of the ratio of the oil phase to the water phase (oil phase weight / water phase weight)
Is preferably 0.02-0.6, particularly 0.1-0.4
Is preferred. If it is 0.02 or less, the amount of the aqueous phase is too large to be diluted and sufficient color developability cannot be obtained, and if it is 0.6 or more, the viscosity of the liquid is increased, which causes inconvenience in handling and a decrease in coating liquid stability.

When the mixed liquid of the emulsified dispersion liquid and the microcapsule liquid (hereinafter referred to as the photoimage forming layer liquid) prepared as described above is applied to both sides of the support, a known water-based or organic solvent-based coating is applied. The application means described later using a liquid is used. In this case, in order to apply the photoimage forming layer liquid safely and uniformly and to maintain the strength of the coating film, in the present invention, as the binder, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, starches, gelatin, polyvinyl alcohol are used. , Carboxy-modified polyvinyl alcohol, polyacrylamide, polystyrene and its copolymers, polyester and its copolymers, polyethylene and its copolymers, epoxy resins, acrylate and methacrylate resins and their copolymers, polyurethane resins and polyamide resins Etc. can be used together with the microcapsules. Incidentally, pigments, waxes, metal soaps, surfactants and the like may be added as appropriate.

In order to produce the photoimage forming material of the present invention, a coating solution containing the above binder and other additives is prepared in the above photoimage forming layer solution, and the light transmittance is 400 to 45.
3% or less in the region of 0 nm and 1% or less in the region of 400 nm or less, wire bar coating, blade coating, slide coating, curtain coating, air knife coating on both sides of a support such as paper or synthetic resin film. Gravure coating, roll coating coating, spray coating, dip coating,
It is applied and dried by a coating method such as spin coating or estrosion coating, and the solid content per surface is 3 to 30 g /
A photoimageable layer of m ² , preferably 4 to 15 g / m ² is provided. The photoimage forming layer thus provided has very good transparency.

Examples of the support used in the present invention include papers from tissue paper to thick cardboard, regenerated cellulose, cellulose acetate, cellulose nitrate, etc.,
Examples thereof include polyethylene terephthalate, polyethylene, polyvinyl acetate, polymethyl methacrylate, polyvinyl chloride and the like. If the support is transparent,
An opaque layer for making it opaque may be provided according to a known method.

The support having the above light transmittance used in the present invention can be easily obtained by incorporating the above light absorber into the above support material by a known method. . In the present invention, the apparent transparency is reduced due to light scattering on the surface of the photoimage forming layer, the photoforming material is attached to a heating roller during heat fixing, blocking of the photoimage forming material and water is attached. In this case, in order to prevent the photoimage forming layer from peeling off from the support (water resistance), it is preferable to provide a protective layer on the photoimage forming layer by a known method.

Details of the protective layer are described, for example, in "Paper Pulp Technology Times" (1985, September issue), pages 2 to 4 and Japanese Patent Application No. 62-287096. In the present invention, a protective layer containing a silicone resin as a main component may be provided together with or in place of the above-mentioned protective layers which have been conventionally used. Thereby, the water resistance can be significantly improved without impairing the transparency of the photoimage forming layer (Japanese Patent Application No. 3-132152).
issue). Waxes and metal soaps may be added to the protective layer. The amount of these used is 0.2 to 7 g / m ² .

The light source for exposure used in the photoimage forming material of the present invention is not particularly limited, and may be natural light, artificial light,
Either monochromatic light, non-coherent light or coherent light can be used. It may be any of a fluorescent lamp, a mercury lamp, a metal halide lamp, a xenon lamp and a tungsten lamp. However, in order to form a suitable image, it is necessary to select a light source having an appropriate light wavelength and light density corresponding to the photoimageable composition. Such a light source and the like are described in detail in Japanese Patent Application No. 62-287096.

[0042]

As described in detail above, the photoimage forming material of the present invention has a photoimage forming layer on both sides of a support and has a light transmittance of 3% or less in a region of 400 to 450 nm.
Since a support having a content of 1% or less in a region of 400 nm or less is used, show-through can be prevented, and a good image can be formed on both sides.

[0043]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.
In addition, "part" indicating the addition amount represents "part by weight".

Example 1. Preparation of capsule liquid tris (4-dimethylaminophenyl) methane 0.3
Part, tris (4-diethylamino-2-methylphenyl) methane 0.7 part, 2,2′-bis- (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole 2 parts, tri 0.4 parts of bromomethylmethylphenyl sulfone and 10 parts of a 75 wt% ethyl acetate solution of a 1/3 adduct of xylylene diisocyanate / trimethylolpropane were added to a mixed solution of 16 parts of ethyl acetate and 14 parts of dicyclohexyl phthalate. , Melted. 5% by weight of the resulting solution with carboxy-modified polyvinyl alcohol
It was added to 64 parts of an aqueous solution and emulsified and dispersed, and the average particle size was 1.
An emulsion dispersion of 6 μm was obtained. Water 5 in the obtained emulsified dispersion.
After adding 8 parts of the mixture and stirring at 40 ° C. for 3 hours to cause the encapsulation reaction, the mixture was cooled to room temperature and filtered to obtain a capsule liquid.

Preparation of reducing agent dispersion 1-phenylpyrazolidine-3- (fendon A) 9.
4 parts and 0.9 parts of p-toluenesulfonamide were added to 23 parts of a 6% by weight aqueous solution of carboxy-modified polyvinyl alcohol and emulsified and dispersed using a horizontal sand mill to obtain a reducing agent dispersion liquid having an average particle diameter of 1 μm. It was

Preparation of coating liquid 165.4 parts of the capsule liquid, 33.3 parts of the reducing agent dispersion liquid, and a dispersion liquid containing 20% by weight of silica (Syloid 40).
4: Fuji Davis Chemical Co., Ltd. product name) 7 parts, 30
3 parts by weight of an epoxidized polyamide resin (FL71: trade name of Toho Chemical Co., Ltd.) and 10 parts by weight of an aqueous solution of 4-methylpentyl sulfosuccinate are mixed in an amount of 3 parts,
A coating liquid was obtained.

Preparation of Photoimage- forming Material The light transmittance in the region of 400 to 450 nm is 3% or less, and the light transmittance in the region of 400 nm or less is 1% or less. The coating solution is applied using a coating rod so that the coating amount becomes 8 g / m ² .
It was dried at 50 ° C. to obtain the photoimageable material of the present invention.

Image recording test Using the obtained photoimage forming material, ultraviolet rays were irradiated from the side of the original on which the line drawing was recorded using an ultrahigh pressure mercury lamp (manufactured by Oak Co., Ltd.) to form an image on the surface. Then, an image was formed on the back side, and an image colored in blue was obtained on each side. The resulting image-formed paper was passed between rollers heated to 135 ° C. at a paper traveling speed of 450 mm / min to fix the unexposed portion. With respect to the photoimage forming material after forming an image in this manner, the non-coloring part (unexposed part) of the color-developing part (exposed part), the non-coloring part (unexposed part) and the color-developing part (exposed part) is formed. Each density was measured using a Macbeth reflection densitometer. The results are as shown in Table 1.

Comparative Example 1. A photoimage forming material was prepared in exactly the same manner as in Example 1 except that the base paper used in Example 1 was replaced with a base paper having a light transmittance of 3% or more (FIG. 2) in the region of 400 to 450 nm. Then, an image was formed, and the density of the image was measured in exactly the same manner as in Example 1. The results are as shown in Table 1.

[0050]

[Table 1] The above results show that show-through can be prevented when images are formed on both sides using the photoimageable material of the present invention.
It is demonstrated that a good image can be formed on both surfaces of the support.

[Brief description of drawings]

FIG. 1 is a drawing in which the light transmittance of the base paper used in Example 1 is measured.

FIG. 2 is a drawing in which the light transmittance of the base paper used in Comparative Example 1 is measured.

Claims (2)

[Claims] 1. An optical image in which a microcapsule containing both an oxidatively colorable leuco dye and a photo-oxidizing agent, and a photo-image forming layer containing a reducing agent are provided on the front and back surfaces of a support. The forming material, wherein the light transmittance of the support is 40
It is 3% or less and 400n in the region of 0 to 450 nm.
A photoimageable material having a content of 1% or less in a region of m or less. 2. The light transmittance of the support is 1% or less in the region of 400 to 450 nm, and 0.
The photoimageable material according to claim 1, which is 5% or less.