JPH05127300A - Image forming material - Google Patents

Abstract

PURPOSE:To provide the image forming material which fogs less before using and has the high density of color developed images and excellent stability by using specific triphenyl methane derivatives as leuco dyes. CONSTITUTION:The triphenyl methane derivatives having aminophenoxy alkyl groups which may have a substituent are used as the leuco dye of the image forming material constituted by forming a coating layer contg. at least microcapsuels contg. the oxidation color developable leuco dyes, a photooxidation agent and a reducing agent on a base. The leuco dyes to be used are the triphenyl methane derivatives expressed by formulas I and II. In the formulas I, II, R<1>, R<3> and R<5> denote a hydrogen atom, alkyl group, aralkyl group or aryl group; R<2>, R<4> and R<6> denote an alkyl group, aralkyl group or aryl group; R denotes the group of formula III. In the formula III, R<7>, R<8> denote an alkyl group or acyl group; X denotes a hydrogen atom, alkyl group, halogen atom; n denotes an integer from 1 to 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image-forming material containing a heat-fixable leuco dye, which can be used for proof paper, printout paper, overlay film and the like. The present invention relates to an image forming material which gives a blue color image having a small amount, a high color image density, and excellent stability.

[0002]

2. Description of the Related Art Conventionally, proof paper, printout paper,
Image-forming materials that can be used in applications such as overlay films have been used in many photographic applications as so-called free radical photography in which a light-sensitive portion is visualized by imagewise exposure.

Particularly effective as such an image-forming material is a method of radical-oxidizing and coloring various leuco dyes into their corresponding dyes using a photo-oxidizing agent. However, since such an image forming material is sensitive to light, color formation occurs when exposed to normal room light, sunlight or white light even after forming a dye image by exposure. It has a problem of causing optical fog and thermal fog. In order to solve this problem, some methods of fixing after image exposure have been proposed. For example, JP-A-2-44 discloses an image forming material in which a leuco dye and a photo-oxidizing agent are encapsulated together in a microcapsule, and a reducing agent is present outside the microcapsule. Has been done. This image-forming material has excellent image reproducibility, raw storability, and image storability, but during long-term storage, there is a problem that color develops (fogging occurs) before use. I knew it was.

[0004]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to reduce fog before use and to increase the density of a color image.
An object of the present invention is to provide an image forming material which gives a blue color image having excellent stability.

[0005]

The present invention provides at least the following:
Microcapsules containing an oxidatively colorable leuco dye and a photo-oxidizing agent, and an image-forming material having a coating layer containing a reducing agent formed on a support, wherein the leuco dye has a substituent. An image forming material characterized by being a triphenylmethane derivative having a good aminophenoxyalkyl group.

The preferred embodiments of the present invention will be described below. (1) The image forming material as described above, wherein the leuco dye is a triphenylmethane derivative represented by the following general formula (1) or general formula (2).

[0007]

[Chemical 1]

[In the formula, R ¹ , R ³ and R ⁵ each independently represent a hydrogen atom, an alkyl group, an aralkyl group or an aryl group, and R ² , R ⁴ and R ⁶ are each independently an alkyl group, Represents an aralkyl group or an aryl group, and R represents
The following general formula (3):

[0009]

[Chemical 2]

(In the formula, R ⁷ and R ⁸ each independently represent an alkyl group, an aralkyl group or an acyl group, X represents a hydrogen atom, an alkyl group or a halogen atom, and n is an integer of 1 to 10, R ⁷ and R ⁸ may be bonded to each other to form a ring which may contain an unsaturated atom or a hetero atom), R ¹ and R ² , R ³ and R ⁴ and R ⁵ and R ⁶ may combine with each other to form a ring which may contain unsaturated atoms or heteroatoms].

[0011]

[Chemical 3]

[Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R have the same meaning as defined in the general formula (1)].

(2) The image forming material as described above, wherein the microcapsules further contain an antioxidant. (3) The ratio of the leuco dye to the photo-oxidizing agent is 10: 1.
The image-forming material as described above, wherein the molar ratio is ˜1: 10. (4) The amount of the reducing agent is 1 to 10 of the amount of the photo-oxidizing agent.
The image-forming material as described above, characterized in that it is 0 mole times.

The leuco dye used in the image-forming material of the present invention is a triphenylmethane derivative having an aminophenoxyalkyl group which may have a substituent. In order for this leuco dye to develop a color and exhibit a blue hue, it is preferable that the three phenyl groups are triphenylmethane derivatives having an amino group having a substituent in the para position to the methine group.

The leuco dye in the present invention is represented by the following general formula (1) or general formula (2) from the viewpoint of easiness of synthesis.
It is preferably a triphenylmethane derivative represented by

[0016]

[Chemical 4]

[In the formula, R ¹ , R ³ and R ⁵ each independently represent a hydrogen atom, an alkyl group, an aralkyl group or an aryl group, and R ² , R ⁴ and R ⁶ are each independently an alkyl group, Represents an aralkyl group or an aryl group, and R represents
The following general formula (3):

[0018]

[Chemical 5]

(Wherein R ⁷ and R ⁸ each independently represents an alkyl group, an aralkyl group or an acyl group, X represents a hydrogen atom, an alkyl group or a halogen atom, and n is an integer of 1 to 10, R ⁷ and R ⁸ may be bonded to each other to form a ring which may contain an unsaturated atom or a hetero atom), R ¹ and R ² , R ³ and R ⁴ and R ⁵ and R ⁶ may combine with each other to form a ring which may contain unsaturated atoms or heteroatoms].

[0020]

[Chemical 6]

[Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R have the same meanings as defined in the general formula (1)].

In the general formulas (1) and (2),
Of the groups represented by R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ , the alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms, and an aryl group. Preferably has 6 to 12 carbon atoms, particularly 6 to 10 carbon atoms, and the aralkyl group preferably has 7 to 12 carbon atoms, particularly 7 to 10 carbon atoms. These groups may be further substituted with an alkoxy group having preferably 1 to 8 carbon atoms, an alkyl group, an aryloxy group having 6 to 10 carbon atoms, an aralkyloxy group and the like. R ¹ and R ² , R ³ and R ⁴ and R ⁵ and R ⁶ are bonded to each other to form a ring containing an unsaturated atom or a hetero atom (for example, piperidyrino group, 1-pyrrolidinyl group, 1-pyrrolyl group, morpholino group). May be formed.

In the general formula (3), among the groups represented by R ⁷ and R ⁸ , the alkyl group is preferably one having 1 to 6 carbon atoms, and the aralkyl group is one having 7 to 10 carbon atoms. Some are preferable, and the acyl group has 1 to 10 carbon atoms.
Are preferred. These groups may be further substituted with an alkoxy group having preferably 1 to 6 carbon atoms, an alkyl group, an aryloxy group having 6 to 10 carbon atoms, an aralkyloxy group and the like. Further, R ⁷ and R ⁸ are bonded to each other to form a ring containing an unsaturated atom or a hetero atom (for example,
A piperidino group, a 1-pyrrolidinyl group, a 1-pyrrolyl group, a morpholino group) may be formed.

Examples of the above alkyl group include methyl,
Examples thereof include ethyl, propyl, isopropyl, butyl, isobutyl, hexyl and octyl. Examples of the above aryl group include phenyl, naphthyl, tolyl, methoxyphenyl and the like. Examples of the above aralkyl group include benzyl, phenethyl, and 4
-Methylbenzyl and the like can be mentioned. Examples of the above acyl group include acetyl, formyl, benzoyl and the like. Examples of the above alkoxy group include methoxy, ethoxy, propoxy, isopropoxy and the like. Phenoxy, naphthoxy, 4-methoxyphenoxy etc. can be mentioned as an example of the said aryloxy group. Examples of the above aralkyloxy group include benzyloxy, phenethyloxy and the like.

From the viewpoint of easy availability of raw materials, R ¹ , R
Preferred as ² , R ³ , R ⁴ , R ⁵ and R ⁶ are a methyl group and an ethyl group. Further, as R ⁷ and R ⁸ , a methyl group, an ethyl group, a propyl group and a butyl group are preferable.

In the general formula (3), among the groups represented by X, the alkyl group is preferably an alkyl group having 1 to 6 carbon atoms as described above, and the halogen atom is a chlorine atom, a fluorine atom or a bromine atom. preferable. It is particularly preferable that X is a hydrogen atom, a methyl group or a chlorine atom. In the general formula (3), n is preferably an integer of 2-4.

In the general formula (3), the substitution position of the amino group is preferably a meta position or a para position with respect to the bonding position of the oxygen atom to the benzene ring.

Specific examples of the group represented by the general formula (3) include 2- (4-dimethylaminophenoxy) ethyl group,
2- (4-diethylaminophenoxy) ethyl group, 3-
(4-Dimethylaminophenoxy) propyl group, 3-
(4-diethylaminophenoxy) propyl group, 2-
(4-diethylaminophenoxy) propyl group, 4-
(4-diethylaminophenoxy) butyl group, 2- (3
-Diethylaminophenoxy) ethyl group, 2- (3-dibutylaminophenoxy) ethyl group, 3- (3-dimethylaminophenoxy) propyl group, 3- (3-diethylaminophenoxy) propyl group, A 2- (3-diethylaminophenoxy) propyl group, a 4- (3-diethylaminophenoxy) butyl group and the like are preferable.

Below, the general formula (1) or the general formula (2)
Specific examples of the triphenylmethane derivative represented by (leuco dye used in the present invention) are shown below, but the present invention is not limited thereto. Bis (4-dimethylaminophenyl)-[4-methyl-
[2- (4-dimethylaminophenoxy) ethyl] aminophenyl] methane, bis (4-dimethylaminophenyl)-[4-methyl- [2- (3-diethylaminophenoxy) ethyl] aminophenyl] methane, Bis (4-
Dimethylaminophenyl)-[4-ethyl- [2- (3
-Diethylaminophenoxy) ethyl] aminophenyl] methane, bis (4-diethylaminophenyl)-
[4-Ethyl- [2- (3-diethylaminophenoxy) ethyl] aminophenyl] methane, bis (4-diethylaminophenyl)-[4-ethyl- [2- (3-dibutylaminophenoxy) ethyl] Aminophenyl] methane, bis (4-diethylaminophenyl)-[4-ethyl- [4- (3-diethylaminophenoxy) butyl] aminophenyl] methane, 2- [bis (4-dimethylaminophenyl) methyl]- 2- (4-Dimethylaminophenoxy) ethyl ester of 5-dimethylaminobenzoic acid, 2- (3-diethylaminophenyl) of 2- [bis (4-dimethylaminophenyl) methyl] -5-dimethylaminobenzoic acid Enoxy) ethyl ester 2- [bis (4-dimethylaminophenyl) methyl]-
2- (3-Dibutylaminophenoxy) ethyl ester of 5-dimethylaminobenzoic acid 2- [bis (4-dimethylaminophenyl) methyl]-
4- (3-Diethylaminophenoxy) butyl ester of 5-dimethylaminobenzoic acid 2- [bis (4-diethylaminophenyl) methyl]-
2- (3-Diethylaminophenoxy) ethyl ester of 5-diethylaminobenzoic acid

By using a triphenylmethane derivative having an aminophenoxyalkyl group which may have a substituent as the leuco dye of the image forming material of the present invention, the image forming material has less fog before use. It is not always clear why the developed image has such a high density as to give a blue image with excellent stability, but the aminophenoxy skeleton in the general formula (3) is a leuco dye. Since it exhibits a fog-preventing action on the mother nucleus, it is considered that introduction of such a skeleton into the molecule of the leuco dye can reduce fog before use (coloring becomes difficult). As shown in the comparative example, tris (p-disubstituted aminophenyl) methane having no aminophenoxy skeleton does not exhibit the excellent effect of the present invention.

In the present invention, another leuco dye may be used in combination with the benzoic acid ester derivative represented by the above general formula (1). Examples of leuco dyes that can be used in combination include, for example, U.S. Pat. No. 3,445,234 and JP-A 61-13787.
6, JP-A-62-94841, JP-A-63.
The following compounds described in Japanese Patent Publication No. -15787 are preferable. When another leuco dye is used in combination with the above benzoic acid ester derivative, the molar ratio of benzoic acid ester derivative: other leuco dye is preferably 100: 0.1 to 1:10. (A) Aminotriarylmethane, aminoxanthene, aminothioxanthene, amino-9,10-dihydroacridine, aminophenoxazine, aminophenothiazine, aminodihydrophenazine, aminodiphenylmethane, leucoindamine, (B) aminohydrocinnamic acid (cyanoethane) , Leucomethine), hydrazine, leucoin digoid dye, amino-2,3-dihydroanthraquinone, tetrahalo-p, p'-biphenol, 2-
(P-Hydroxyphenyl) -4,5-diphenylimidazole, phenethylaniline. Among these leuco forms, (A) loses one hydrogen atom and (B) loses two hydrogen atoms to form a host dye.

Specifically, tris (4-dimethylaminophenyl) methane, tris (4-diethylaminophenyl) methane, tris (4-diethylamino-2-methylphenyl) 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 , 3,6-bis (diethylamino) -9-
Phenylxanthene, 3,6-bis (dimethylamino)
-9- (o-methoxycarbonylphenyl) xanthene, 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 can be mentioned.

The image forming material of the present invention uses the benzoic acid ester derivative represented by the general formula (1) as the leuco dye, and the image forming material described in JP-A-2-44. Is the same as.

Preferred photo-oxidizing agents which can be used in the image-forming material of the present invention are inert until exposed to actinic rays such as visible rays, ultraviolet rays, infrared rays and X-rays. When exposed to light, it produces chemical species that oxidize the leuco dye to its chromogenic form.

As a typical photo-oxidizing agent, Japanese Patent Publication No. 62-
Lophine dimer compounds such as 2,4,5-triarylimidazole dimers described in Japanese Patent Publication No. 39728 and Japanese Patent Publication No. 63-2099, 2-azidobenzoxazole, benzoylazide, and 2-described in U.S. Pat. No. 3,282,693. Azide compounds such as azidobenzimidazole, pyridinium such as 3'-ethyl-1-methoxy-2-pyridothiacyanine perchlorate and 1-methoxy-2-methylpyridinium-p-toluenesulfonate described in U.S. Pat. No. 3,615,568. Compound, N-bromosuccinimide, tribromomethylphenyl sulfone, 2-trichloromethyl-5- (p-butoxystyryl) -1,3,4-oxadiazole, 2,6-ditrichloromethyl-4- (p -Methoxyphenyl) -triazine and other organic halogens Compounds, mention may be made of an azide polymer, and the like of the Society of Photographic Science and Technology of Japan 1968 Spring Research Workshop Abstracts page 55 described. Of these, the lophine dimer compound and the organic halogen compound are preferable, and the combined use of both is most preferable because high sensitivity can be realized.

In the production of the image-forming material of the present invention, the leuco dye and the photo-oxidizing agent are used in a molar ratio of 10: 1 to 1: 1.
It is advisable to mix them in a ratio of 10, and a more preferable mixing ratio is a molar ratio of 2: 1 to 1: 2.

In the present invention, the preferable microcapsules for encapsulating the leuco dye and the photo-oxidizing agent are heated to a certain temperature or higher at room temperature due to the substance separating action of the walls of the microcapsule preventing contact between substances inside and outside the capsule. Only when the permeability of the substance is increased. With respect to this phenomenon, the permeation initiation temperature can be freely controlled by appropriately selecting the capsule wall material, the capsule core substance, and the additive. The permeation initiation temperature in this case corresponds to the glass transition temperature of the capsule wall.

In order to control the glass transition temperature inherent to the microcapsule wall, it is necessary to change the type of capsule wall forming agent. Examples of the capsule wall material that can be used in the present invention include polyurethane, polyurea, polyamide,
Examples thereof include polyesters, polycarbonates and the like, and blends thereof. Among them, polyurethane and polyurea are particularly preferable.

The microcapsules used in the present invention are prepared by emulsifying a core substance containing an image forming substance such as a leuco dye and a photo-oxidizing agent, and then forming a wall of the wall forming material around the emulsified oil droplets. Made In this case, a reactant for forming a wall is added inside the oil droplet and / or outside the oil droplet.

A high boiling point oil (having a boiling point of 120 ° C. or higher) is used as the organic solvent for dissolving the above image forming substance. As the high boiling point oil, phosphoric acid ester, phthalic acid ester, acrylic acid ester, methacrylic acid ester, other carboxylic acid ester, fatty acid amide, alkylated biphenyl, alkylated terphenyl, alkylated naphthalene, diarylethane, chlorinated paraffin Etc. Specific compounds include, for example, JP-A 60-242094 and JP-A 62-62.
Those described in Japanese Patent No. 75409 can be used.

In the present invention, the above high boiling point oil has a low boiling point auxiliary solvent (having a boiling point of less than 120 ° C.).
Can also be added. Specific examples of the auxiliary solvent include ethyl acetate, isopropyl acetate, butyl acetate, methylene chloride and cyclohexanone.

In order to make the emulsified oil droplets stable, a protective colloid or a surfactant can be added to the aqueous phase. As the protective colloid, generally, a water-soluble polymer (eg, polyvinyl alcohol, gelatin, cellulose derivative, etc.) can be used.

In the present invention, the size of the microcapsules is, in particular, from the viewpoint of image resolution improvement and handleability.
The volume average particle size according to the measuring method described in JP-A-60-214990 is preferably 20 μm or less, and particularly preferably 4 μm or less. The lower limit of the capsule size depends on the nature of the substrate or support, but is generally preferably 0.1 μm or more.

In the image forming material of the present invention, an antioxidant may be contained in the microcapsules in order to further impart stability before use. As the antioxidant, a phenol compound, a hydroquinone compound, a catechol compound and the like are preferable. Specific compounds of the antioxidant include 2,6-di-t-butyl-4-methylphenol, 2,4,6-tri-t-butylphenol,
2,5-di-t-butylhydroquinone, 2,3-di-
Examples thereof include t-butyl hydroquinone, 2,5-di-t-octyl hydroquinone, 2,5-di-t-amyl hydroquinone, and 3,6-di-t-butyl catechol.

In producing the image-forming material of the present invention, the photo-oxidizing agent and the antioxidant are used in a molar ratio of 10: 0.001 to
It is preferable to mix them in a ratio of 10: 2, particularly 10: 0.01 to 10: 1.

In the present invention, any known sensitizer may be added to the microcapsules.

The image-forming material of the present invention can be exposed to light to form an image and then subjected to heat treatment to reliably obtain a stable image. That is, the fixing mechanism of the image forming material of the present invention is such that the photooxidizing agent and the reducing agent come into contact with each other through the microcapsule wall by heating, and the reducing agent acts and oxidizes even if the photooxidizing agent is subsequently activated. This is because the agent is inactivated and the leuco dye no longer develops color. Such a reducing agent acts as a so-called free radical scavenger that traps the free radicals of the activated photo-oxidizing agent.

Examples of the reducing agent in the present invention include:
JP-A-2-44 discloses a hydroquinone compound having a hydroxyl group on a benzene ring and at least another hydroxyl group or an amino group at another position of the benzene ring, an aminophenol compound, a cyclic phenylhydrazide compound, and further guanidine. A compound selected from a derivative, an alkylenediamine derivative and a hydroxyamine derivative, a phenylhydrazine compound or the like can be used. Specific examples of the reducing agent include hydroquinone, catechol, resorcinol, hydroxyhydroquinone, pyrrologricinol, aminophenol, 1-phenylpyrazolidin-3-one (phenidone A), 1-phenyl-4-methyl. Pyrazolidin-3-one (phenidone B), 3-methyl-1- (p-sulfophenyl) -2-pyrazolin-5
-One, 3-methyl-1-phenyl-2-pyrazoline-
5-on and the like can be mentioned.

In the image forming material of the present invention, the reducing agent is not encapsulated in microcapsules but is solid-dispersed by a sand mill or the like, or is dissolved in oil and emulsified and dispersed. When solid-dispersing or emulsifying, it is preferred to use protective colloids similar to those mentioned above for the preparation of microcapsules. The amount of the reducing agent is preferably 1 to 100 times, and more preferably 5 to 20 times the molar amount of the photooxidant component.

The fixing of the image in the present invention can be effectively achieved by the contact of the photo-oxidizing agent and the reducing agent through the capsule wall by heating as described above, but it is synergistic by simultaneous heating and pressurization. You can also expect a great effect. It is preferable to use a melting point depressant such as p-benzyloxyphenol or p-toluenesulfonamide together with this reducing agent because fixing can be performed at a relatively low temperature.

The image-forming material of the present invention is the same as the method described in JP-A-2-44, except that the benzoic acid ester derivative represented by the general formula (1) is used as the leuco dye. Can be manufactured.

That is, the image-forming material of the present invention can be prepared by coating on a support as a dispersion of microcapsules containing the specified leuco dye and a photo-oxidizing agent and a reducing agent.

A binder, a pigment, a wax, a metal soap or a surfactant may be further added to the dispersion of the microcapsules containing the leuco dye and the photo-oxidizing agent and the reducing agent. The coating amount of the image forming layer in the invention is
3 to 30 g / m ^{2 in} terms of solid content, especially 5 to 20 g / m ²
Is preferred.

Suitable materials for the support include, for example, papers from tissue paper to thick ball paper, recycled cellulose, cellulose acetate, cellulose nitrate.
Examples thereof include films of polymers such as polyester, polyethylene terephthalate, polyethylene, polyvinyl acetate, polymethyl methacrylate, polyvinyl chloride and the like.

The coating solution for the image-forming layer is applied to the support by an air-knife coat method, a carten coat method,
Slide coating method, roller coating method, dip coating method, wire bar coating method, blade coating method, gravure coating method, spin coating method or extrusion coating method. However, the method is not limited to these.

If desired, an undercoat layer may be provided on the support, or a coating layer may be provided on the image forming layer. The undercoat layer and the coating layer are mainly composed of a binder and / or
Or it contains a pigment.

The method of forming an image using the image forming material of the present invention and fixing the obtained image is the same as the method described in JP-A-2-44 itself. Imagewise exposure to the imaging element of the present invention may be accomplished, for example, by writing with a beam of activating light or by exposing a selected area of a negative, stencil or other relatively opaque pattern to a suitable light source (eg, fluorescent light). Lamp, mercury lamp, metal halide lamp, xenon lamp, tungsten lamp, etc.)
Can be used for exposure. As a result, the photo-oxidant is activated and a leuco dye image is formed. The fixing of the formed image is performed by heating the temperature of the wall material of the microcapsule to a temperature above its glass transition temperature and contacting the photooxidizing agent and the reducing agent through the wall of the capsule. You can On this occasion,
You may pressurize simultaneously.

The image forming material of the present invention is used as an image forming material having improved background light yellowing and powder blowing.

[0059]

EXAMPLES Examples will be shown below, but the present invention is not limited thereto. In addition, "part" which shows an addition amount shows "weight part.

Example 1 Bis (4-diethylaminophenyl)-[4-ethyl- [2- (3-diethylaminophenoxy) ethyl] aminophenyl] methane [leuco dye] 1.5 parts, 2,2 '-Bis- (o-chlorophenyl) -4,4', 5,5'-tetraphenylbiimidazole [photooxidant] 2 parts, tribromomethylphenyl sulfone 0.4 part and xylylene diisocyanate / trimethylolpropane 75 wt% ethyl acetate solution of adduct 1
0 part was added to a mixed solvent of 16 parts of ethyl acetate and 14 parts of dicyclohexyl phthalate and dissolved. This solution
Add to 64 parts of a 5% by weight aqueous solution of carboxy-modified polyvinyl alcohol, emulsify and disperse at 20 ° C., average particle size 1
A μm emulsion was obtained. 58 parts of water was added to the obtained emulsion, and the mixture was continuously stirred at 40 ° C. for 3 hours. Then, the mixture was returned to room temperature and filtered to obtain a capsule dispersion liquid.

Next, 1-phenylpyrazolidin-3-one (phenidone A) [reducing agent] 9.4 parts and p-toluenesulfonamide 0.9 part were added to a 6 wt% aqueous solution of carboxy-modified polyvinyl alcohol 23. In addition to the parts, the mixture was dispersed by a horizontal sand mill to obtain a reducing agent-containing dispersion liquid having an average particle diameter of 1 μm.

Next, a coating solution having the following composition was prepared. 165.4 parts of the above capsule dispersion 33.3 parts of the above Phenidone A dispersion 33.3 parts 20% silica (Cyroid 404, manufactured by Fuji Devison Chemical Co., Ltd.) dispersion 7 parts 30% epoxidized polyamide resin (FL-71, Toho Chemical ( Co., Ltd.) 3 parts 10% sulfosuccinic acid 4-methylpentyl ester aqueous solution 3 parts

This coating solution was applied to wood free paper (grammage 76 g / m ² ).
Was coated with a coating rod at a solid coating amount of 10 g / m ² and dried at 50 ° C. to obtain an image forming material.

[Embodiment 2] In Embodiment 1, the bis (4-
Diethylaminophenyl)-[4-ethyl- [2- (3
2- (bis (4-dimethylaminophenyl) methyl] -5-dimethylaminobenzoic acid 2- (3-diethylaminophenoxy) ethyl ester 1 instead of -diethylaminophenoxy) ethyl] aminophenyl] methane An image forming material was obtained in the same manner as in Example 1 except that 0.5 part was used.

Comparative Example 1 In Example 1, bis (4-
Diethylaminophenyl)-[4-ethyl- [2- (3
An image forming material was obtained in the same manner as in Example 1 except that 1.0 part of tris (4-diethylaminophenyl) methane was used instead of -diethylaminophenoxy) ethyl] aminophenyl] methane. ..

Comparative Example 2 Instead of 2- (3-diethylaminophenoxy) ethyl ester of 2- [bis (4-dimethylaminophenyl) methyl] -5-dimethylaminobenzoic acid in Example 2 Example 2 except that 1.0 part of the ethyl ester of 2- [bis (4-dimethylaminophenyl) methyl] -5-dimethylaminobenzoic acid was used as
In the same manner as described above, an image forming material was obtained.

Example 3 1.5 parts of 2- [3-diethylaminophenoxy) ethyl ester of 2- [bis (4-dimethylaminophenyl) methyl] -5-dimethylaminobenzoic acid, 2,2 '-Bis- (o-chlorophenyl)
-4,4 ', 5,5'-Tetraphenylbiimidazole 2 parts, tribromomethylphenyl sulfone 0.4 part,
75 wt% ethyl acetate solution 1 of 2,5-di-t-octylhydroquinone [antioxidant] 0.1 part and xylylene diisocyanate / trimethylol propane adduct 1
0 part was added to a mixed solvent of 16 parts of ethyl acetate and 14 parts of dicyclohexyl phthalate and dissolved. This solution
Add to 64 parts of a 5% by weight aqueous solution of carboxy-modified polyvinyl alcohol, emulsify and disperse at 20 ° C., average particle size 1
A μm emulsion was obtained. 58 parts of water was added to the obtained emulsion, and the mixture was continuously stirred at 40 ° C. for 3 hours. Then, the mixture was returned to room temperature and filtered to obtain a capsule dispersion liquid.

An image-forming material was obtained in the same manner as in Example 1, except that this capsule dispersion was used instead of the capsule dispersion in Example 1.

COMPARATIVE EXAMPLE 2 In Example 3, 2- (3-diethylaminophenoxy) ethyl ester of 2- [bis (4-dimethylaminophenyl) methyl] -5-dimethylaminobenzoic acid 1. 2- [bis (4
-Dimethylaminophenyl) methyl] -5-dimethylaminobenzoate The image forming material was obtained in the same manner as in Example 3 except that 1.0 part of the ethyl ester was used.

The image forming materials obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were tested as follows. The results are shown in Table 1. (1) Image Density A fresh sample was irradiated with light through a line drawing original by a jet light (ultra high pressure mercury lamp, manufactured by Oak Co., Ltd.) to obtain a yellow image. Then, the unexposed portion was fixed by passing it through a heating roller at 135 ° C. at a speed of 450 mm / min. Then, the image density of the exposed portion was measured with a Macbeth reflection densitometer. (2) Fog before use Fresh samples were stored for 1 week in the dark at a temperature of 45 ° C and a relative humidity of 30%, and the fog density was measured by a Macbeth reflection densitometer. (3) Stability of image area After the above heat-fixed sample was irradiated with a fluorescent lamp of 32000 lux for 10 hours, the density of the image area was measured with a Macbeth reflection densitometer and the image density before irradiation with the fluorescent lamp was measured. Compared with.

[0071]

[Table 1]

As is clear from the data in Table 1, the image-forming materials of the present invention obtained in each of the examples were compared with the image-forming materials of each comparative example using a leuco dye outside the scope of the present invention. Further, it is an image forming material having less fog before use, high density of a color image, and excellent stability of an image area.

[0073]

The image-forming material of the present invention has the remarkable effects of providing a color image with less fog before use, high density of a color image and excellent stability.

Claims (2)

[Claims] 1. An image forming material comprising a support and a coating layer containing a reducing agent and a microcapsule containing at least an oxidative colorable leuco dye and a photo-oxidizing agent, wherein the leuco dye is substituted. An image forming material, which is a triphenylmethane derivative having an aminophenoxyalkyl group which may have a group. 2. The image forming material according to claim 1, wherein an antioxidant is further contained in the microcapsules.