JPH0325434A - Light image forming material - Google Patents

Abstract

PURPOSE:To obtain a thermally fixable light image forming material having improved fixability of printing and improved aging stability after printing by using a specified arylhydrazide compd. as a reducing agent. CONSTITUTION:An arylhydrazide compd. represented by formula I is used as a reducing agent. In formula I, Ar is aryl, R1 is H, alkyl or aryl, R2 is alkyl or aryl, groups represented by Ar, R1 and R2 may be substd. by alkyl, alkenyl, etc., and these substituents may have substituents. A thermally fixable light image forming material having the improved fixability of printing and the improved aging stability after printing is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to photoimageable materials, and particularly to heat-fixable leuco dye-based photoimageable materials.

More specifically, the present invention relates to a photoimage-forming material that has improved background photoyellowing and dusting, and has excellent heat fixability.

"Prior Art" Conventionally, photoimage-forming materials that can be used for proofing paper, printout paper, overlay film, etc.
Many photographic applications have been made for so-called free radical photography, in which photosensitive areas are visualized by imagewise exposure.

Particularly effective in this regard is the method of radical oxidative color development of various leuco dyes into their corresponding dyes using a photooxidizing agent.

However, because they are sensitive to light, even after exposure to dye images, color formation occurs when exposed to normal indoor light, sunlight, or white light; therefore, they are sensitive to such light. Handling of image-shaped material is difficult.

Therefore, in order to retain the image once it has been formed, as a method to prevent color from appearing in the unexposed areas during image exposure,
A method of preserving the original image by applying a solution of a reducing agent, such as a free radical scavenger, to the imaged material, e.g. by spraying or smearing, and e.g.
Japanese Patent Publication No. 12879 describes a method of forming an image with UV light and fixing it by activating a photo-reducing substance with visible light, and Japanese Patent Publication No. 43-29407 describes a method of forming an image with UV light and fixing it by activating a photoreducing substance. or coated on the photosensitive layer.
A method has been proposed in which heat fixing is performed after image exposure.

However, none of these methods were satisfactory. Therefore, the present inventors. As a result of extensive research, we have discovered a photoimage-forming material in which a leuco dye and a photooxidizing agent are encapsulated together in microcapsules, and a reducing agent is present outside the microcapsules. (Patent Application No. 62-259111) However,
It has been found that this pre-image forming material has problems with print fixing properties, stability over time after printing, and the like.

``Object of the Invention'' Accordingly, an object of the present invention is to provide a heat-fixable photoimage-forming material with improved print fixability and stability over time after printing.

"Means for Solving the Problem" The above-mentioned object of the present invention is to provide a photoimage-forming material in which a coating layer containing at least an oxidative color-forming leuco dye, a photo-oxidizing agent, and a reducing agent is formed on a support. , a photoimage-forming material characterized in that the reducing agent is an aryl hydrazide compound represented by the following general formula [I]. A r N N H C O R2
(1) R (In the formula, A. r represents an aryl group, R+ represents a hydrogen atom, an alkyl group, or an aryl group. Rl represents an alkyl group or an aryl group.) In the above formula, represented by Ar, R1, and R, The groups further include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a hydrogen atom, a substituted amino group, an alkoxy group, an aryloxy group, an alkylthio group, a nitrogen atom, a nitro group, a cyano group, a substituted carbamoyl group, It may be substituted with a substituted oxycarbamoyl group, substituted oxysulfonyl group, carpoxyl group, heterocycle, etc. . These substituents may further have a substituent.

In the above formula, the aryl group represented by Ar is preferably a benzene ring, a naphthalene ring, a pyridine ring, a 'furan ring, a coumarin ring, etc., and a benzene ring or a naphthalene ring is particularly preferable.

Particularly preferable substituents for Ar include a methyl group, an ethyl group, a methoxy group, an ethoxy group, a chlorine atom, and a fluorine atom.

Among the groups represented by R, a hydrogen atom, an alkyl group, and an aryl group are preferred, and a hydrogen atom, a methyl group, an ethyl group, and a phenyl group are particularly preferred. Among the groups represented by R1,
Specific examples of the compound of the general formula (I) according to the present invention are listed below, in which an alkyl group, an aryl-substituted alkyl group, an aryloxyalkyl group, and an aryl group are preferable, but the present invention is not limited thereto.

N"-Phenyl acetohydrazide N' - Phenylbutyryl hydrazide N' - Phenylbutyryl hydrazide N" - Phenylvaleryl hydrazide N' - Phenylisovaleryl hydrazide N' - Phenylhexanoyl hydrazide N゜-Phenyloctanoylhydrazide N゜-Phenyllauroylhydrazide N゛-Phenylphenylacetylhydrazide N゛ -Phenylphenoxyacetylhydrazide N゛-Phenylbenzoylhydrazide N゛ -Phenylacryloylhydrazide N'-Phenyl-N゛ - Methylprobionyl hydrazide N゜-phenyl-N゜-methylacetylhydrazide N゜-phenyl-N'-methylbutyrylhydrazide N゜-phenyl-(3-carboxylpropionyl) hydrazide N'-p-chlorophenylbutyrylhydrazide Nl-p
-Methylphenylbutyrylhydrazide N' -p-methoxyphenylbutyrylhydrazide N', N' -
Examples include diphenylbutyrylhydrazide N'N'-diphenylacetylhydrazide. The compound of the general formula [E] of the present invention can be obtained by acylating the corresponding arylhydrazine derivative.

In turn, the leuco dyes which constitute a component of the photoimageable materials of the present invention are reduced forms of dyes having one or two hydrogen atoms, with the removal of the hydrogen atom and in some cases the addition of additional electrons. Addition produces color and shapes the dye. Since such leuco dyes are substantially colorless or have a weak color, when they oxidize and develop color, they serve as a means for forming a pattern. This oxidation is counteracted in the present invention by the presence of at least one photooxidizing agent. This photooxidant is activated by light irradiation and reacts with the leuco dye to produce a colored image against a background of unirradiated and therefore unchanged material.

In addition to the above-mentioned compounds as leuco dyes according to the present invention,
Color tone adjustment may be performed by using materials having other skeletons in combination. For example, US Patent No. 344
Preferred are those described in No. 5234.

Specifically, leuco crystal violet, tris(4-diethylamino-o-}lyl)-methane, bis-
(4-diethylamino-0-tolyl)-phenylmethane, bis-(4-diethylamino-0-tolyl)-thenyl-2-methane, bis-(2-chloro-4-diethylaminophenyl)-phenylmethane, 2- (2- chlorophenyl)amino-6-N,N-dibutylamino-9-
(2-methoxycarbonyl)-phenylxanthene, 2
-N,N-dibenzylamino-6-N. N-diethylamino-9-(2-methoxycarbonyl)-phenylxanthene, benzo(a)-6-N. N-diethylamino-9-(2-methoxycarbonyl)-phenylxanthene, 2-(2-chlorophenyl)-mono-6-N,N-
Dibutylamino-9-(2-methylphenylcarboxamide)-phenylxanthene, 3,6-dimethoxy-9
- (2-Methoxycarbonyl)-1 phenylxanthene, 3,6-diethoxyethyl-9-(2-methoxycarbonyl)-1 phenino V xanthene, penzoylleucomethylene blue-3,7-bis-diethylaminophenoxazine, etc. can.

On the other hand, the photooxidizing agent in the photoimageable material of the present invention is normally inert, but when exposed to active radiation such as visible light, ultraviolet light, infrared light, or X-rays, it converts the leuco dye into its colored form. It produces chemical species that oxidize.

As a typical photo-oxidizing agent, Japanese Patent Publication No. 6 2-3 972
8, 2.4.5-triaryl imidazole dimer described in Japanese Patent Publication No. 63-2099, 2-azidobenzoxazole, penzoyl azide, and 2-azidobenzimidazole described in U.S. Pat. No. 3,282,693. Azide compounds such as U.S. Patent No. 36155
Viridinium compounds such as 3-ethyl-l-methoxy 2-pyridothiacyanine verchlorate and l-methoxy-2-methylpyridinium-p-1 luenesulfonate described in No. 68, N-promosuccinimide, tribromomethylphenyl Sulfone, 2-trichloromethyl-5-
Organic halogen compounds such as (p-butoxystyryl)-1,3,4-oxadiazole, 2,6-ditriclomethyl-4-(p-methoxyphenyl)monotriazine, Photographic Society of Japan 1968 Spring Research Presentation Examples include the azide polymer described on page 55 of the conference abstract. Among these, lophine dimer compounds and organic halogen compounds are preferred, and the combination of both is optimal because high sensitivity can be achieved.

In producing the photoimageable material of the present invention, the leuco dye and the photooxidizing agent are preferably mixed in a molar ratio of 10:1 to 1:10, and a more preferable mixing ratio is 2:1 to 1:2. It is.

The reducing agent according to the present invention acts as a so-called free radical scavenger that traps the free radicals of the activated photo-oxidizing agent.

The reducing agent represented by the general formula (I) of the present invention is a hydroquinone described in U.S. Pat. Compounds such as aminophenol compounds, cyclic phenylhydrazide compounds described in Japanese Patent Publication No. 62-39728, and compounds selected from guanidine derivatives, alkylene diamine derivatives, and droxyamine derivatives may be used in combination. In the photoimage-forming material of the present invention, the reducing agent is preferably used by solid dispersion using a sand mill or the like, or by dissolving it in oil and emulsifying it. It is preferable to use a protective colloid during solid dispersion or emulsion dispersion.

The preferred amount of reducing agent is from 1 to 1 on a mole basis of the photooxidant component.
00 times the molar amount, more preferably 5 to 20 times the molar amount.

A specific form of the photoimage forming material according to the present invention will be explained.

The photoimage-forming material according to the present invention contains a leuco dye, a photooxidizing agent, and a reducing agent as essential components, and it is preferable that one or two of these are encapsulated in microcapsules. Preferably a leuco dye, preferably encapsulated.

A preferred capsule is one in which at room temperature, the isolation effect of the microcapsule wall prevents contact between substances inside and outside the capsule, and the permeability of substances increases only when heated above a certain temperature. The permeation start temperature of this phenomenon can be freely controlled by appropriately selecting the capsule wall material, capsule core material, and additives. Wall materials that can be used in the present invention include polyurethane, polyurea,
Examples include polyamide, polyester, polycarbonate, etc., among which polyurethane and polyurea are particularly preferred.

Microcapsules are made by emulsifying a core material containing a photoimageable material such as a leuco dye and a photooxidizing agent, and then forming a wall of polymeric material around the emulsified oil droplets. In this case, the wall-forming actant is added to the interior of the oil droplet and/or to the exterior of the oil droplet. Specific methods for microencapsulation are described in U.S. Patent Nos. 3726804 and 37966flF6.
This is carried out by the method described in Japanese Patent Application No. 62-259111.

High boiling point oils are used as organic solvents to dissolve the photoimage-forming substances mentioned above, specifically phosphoric acid esters, phthalic acid esters, acrylic acid esters, methacrylic acid esters, other carboxylic acid esters, fatty acid amides, alkyl esters, etc. Examples thereof include biphenyls, alkylated terphenyls, alkylated naphthalenes, diarylethanes, and chlorinated baraffins.

In the present invention, a low boiling point auxiliary solvent can also be added to the above organic solvent. Specific examples of the auxiliary solvent include ethyl acetate, isoprobyl acetate, butyl acetate, methylene chloride, cyclohexanone, and the like.

In order to stably form emulsified oil droplets, protective colloids and surfactants can be added to the aqueous phase. Generally, water-soluble polymers can be used as the protective colloid, but carboxy-modified polyvinyl alcohol is preferably used to improve water resistance.

The size of the microcapsules particularly improves image resolution,
From the viewpoint of ease of handling, the volume average size is preferably 20 μm or less, more preferably 4 μm or less.

In the present invention, an acidic substance may be added into the capsule. Examples of acidic substances include mineral acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, and phosphoric acid, p-toluenesulfonic acid, benzenesulfonic acid, chlorobenzenesulfonic acid,
Aromatic sulfonic acid derivatives such as nitrobenzenesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, benzoic acid, chlorobenzoic acid, nitrobenzoic acid, hydroxybenzoic acid, toluic acid, salicylic acid, butylsalicylic acid, amylsalicylic acid, phenylsalicylic acid, Examples include aromatic sulfonic acid derivatives such as naphthoic acid and salts thereof.

In the present invention, there is no problem in adding a known sensitizer, ultraviolet absorber, or antioxidant into the capsule.

The photoimage-forming material of the present invention can be prepared by coating on a support a dispersion of microcapsules containing such a leuco dye and a photooxidizing agent and a reducing agent.

Microcapsules containing the above leuco dye and photooxidizing agent and a dispersion of a reducing agent are combined with binders, pigments, waxes, metal soaps, surfactants, and melting point depressants such as p-benzyloxyphenol and p-toluenesulfonamide. and an acidic substance may be added, and the coating amount of the photoimage forming layer in the present invention is 3 to 30 g/m'' in terms of solid content, particularly 5 g/m''.
~20 g/mt is preferred.

Suitable materials for the support include papers ranging from tissue paper to thick cardboard, regenerated cellulose, cellulose acetate, cellulose nitrate, polyethylene terephthalate, polyethylene, polyvinyl acetate, polymethyl methacrylate, polyvinyl chloride, and the like.

Methods for coating the support include air knife coating, curtain coating, slide coating, roller coating, dip coating, wire bar coating, blade coating, gravure coating, spin coating, or extrusion coating. etc., but are not limited to these.

Further, if necessary, an undercoat layer may be provided on the support, or a coating layer may be provided on the photoimage forming layer. The undercoat layer and coating layer are mainly formed from a binder and/or a pigment. General image forming methods for the photoimage-forming material of the present invention include a method of imagewise exposure to form a colored image and then heat fixing, and a method of imagewise thermal printing and then photocoloring. I don't really mind.

In the former case, image fixation can be effectively achieved by contacting the photooxidizing agent and reducing agent through the capsule wall through heating, but a synergistic effect can also be expected by applying heating and pressure at the same time. .

Further, if the microcapsules are appropriately selected, fixing can be performed only by pressure.

Any light source can be used in the present invention to activate the canine oxidizer and image the leuco dye. Conventional light sources include fluorescent lamps, mercury lamps, metal halide lamps, xenon lamps, tungsten lamps, and the like.

In addition, various methods can be used for thermal heating, but
Heating is generally done using a thermal head, heat roller, heat stamp, hot plate, etc.

Examples will be shown below, but the present invention is not limited thereto. Note that "parts" indicating the amount added indicate "parts by weight."

"Example" Example 1 1 part of leuco crystal violet, 2.2-bissu (
2 parts of 0-chlorophenyl)-4,4',5,5-tetraphenylbiimidazole, 0.4 part of tribromomethylphenylsulfone, 0.1 part of 2,5-tertiary octylhydroquinone, and xylylene diisocyanate/tri 10 parts of a 75% by weight ethyl acetate solution of the methylolpropane adduct was added to and dissolved in a mixed solvent of 16 parts of ethyl acetate and 14 parts of dicyclohexyl phthalate.

This solution was added to 64 parts of a 5% by weight aqueous solution of carboxy-modified polyvinyl alcohol, and emulsified at 20°C to obtain an emulsion having an average particle size of 1 μm. 58 parts of water was added to the resulting emulsion, and stirring was continued at 40°C for 3 hours.

Thereafter, the mixture was returned to room temperature and filtered to obtain a capsule dispersion.

Next, 9.4 parts of N°-phenylbutyryl hydrazide and 0.9 parts of p-}luenesulfonamide, which are reducing agents, were added to 23 parts of a 6% by weight aqueous solution of carboxy-modified polyvinyl alcohol.
part and dispersed in a horizontal sand mill to obtain an average particle size lμ
A reducing agent-containing dispersion was obtained.

Next, a coating liquid having the following composition was prepared.

The above capsule dispersion The above reducing agent dispersion 20% silica (Thyroid 404, Fuji Davison Chemical (
7 parts 30% epoxidized polyamide resin (FL-71, manufactured by Toho Chemical)
3 parts lO% sulfosuccinic acid 4
-Methylbentyl ester aqueous solution
Apply 3 parts of this coating solution to high-quality paper (basis weight: 16 g)
/m2) with coating rod, solid coating amount 10g/m2
! The photoimage-forming material was dried at 50°C.

Example 2 A photoimage-forming material was obtained in the same manner as in Example 1, except that N°-phenylisobutyryl hydrazide was used in place of N°-phenylbutyrylhydrazide in Example 1.

Comparative Example 1 The photoimage-forming material was prepared in the same manner as in Example 1, except that l-phenylvirazolidine-3-one (phenidone A) was used instead of N-phenylbutyrylhydrazide in Example 1. Obtained.

The photoimage forming materials obtained in Examples and Comparative Examples 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 manuscript using a jet light (an ultra-high pressure mercury lamp, manufactured by Oak Co., Ltd.), and the image density of the exposed area was measured using a Macbeth reflection densitometer.

(2) Heat fixability The sample after the image formation described above was passed through a heating roller at 135° C. at a speed of 450 mm/min, and then irradiated with light using a jet light to observe whether there was any change in the image.

(3) Stability over time After the above-mentioned heat-fixed sample was left in a 90% atmosphere at 40° C. for 48 hours, changes in the image area and background area were visually observed.

The results are shown in Table 1. "Effects of the Invention" It can be seen that by using the aryl hydrazide compound of the present invention, the stability after fixing can be improved without adversely affecting image density and heat fixability.

Claims (1)

[Scope of Claims] A photoimage-forming material in which a coating layer is formed on a support, the coating layer comprising at least a leuco dye capable of oxidative color development, a photooxidizing agent, and a reducing agent as essential components, wherein the reducing agent is represented by the following general formula [I] A photoimage-forming material characterized by being an aryl hydrazide compound represented by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, Ar represents an aryl group, R_1 represents a hydrogen atom, an alkyl group, or an aryl group, and R_2 represents an alkyl group or an aryl group.)