JPH02190843A - Optical image forming material - Google Patents

Abstract

PURPOSE:To improve the stability of formed images and to allow heat fixing of black in color developing hue by forming a leuco dye of a compd. having acridan skeleton. CONSTITUTION:The leuco dye which constitutes one component of the optical image forming material is of a reduction type of a dye having 1 or 2 hydrogen atoms. This dye develops a color and forms dye by addition of additional electrons when the hydrogen atoms are removed or exist. Such leuco dye is substantially colorless or has a pale color and, therefore, a means of forming patterns is obtd. when the dye is oxidized to develop the color. This oxidation is attained by allowing a photooxidizing agent to exist. The photooxidizing agent is activated by irradiation of light and reacts with the leuco dye to form the chromatic image only in the part irradiated with the light. The stability of the formed images is improved in this way and the optical image formation of black in color developing hue is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to photoimageable materials, and more particularly to fixable leuco dye-based photoimageable materials. More specifically, the present invention relates to a photoimage-forming material that has excellent stability in formed images and has a black color hue.

"Prior Art" Conventionally, photoimageable materials that can be used for applications such as blue paper, printout paper, and overlay films are:
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 oxidizing various leuco dyes to the 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. Imaging materials are difficult to handle.

For this reason - in order to preserve the image once formed, a solution of a reducing agent, such as a free radical scavenger, is applied to the imaged material, for example by spraying or impregnation, as a method of preventing the development of color in unirradiated areas during image exposure. A method of preserving the original image by
・The specification describes a method of forming an image with UV light and fixing by activating a photoreducing substance with visible light, and the specification of Japanese Patent Publication No. 43-29407 describes a method of forming an image with UV light and fixing by activating a photoreducing substance. Contained in the photosensitive layer or coated on the photosensitive layer,
A method has been proposed in which heat fixing is performed after image exposure.

When attempting to obtain a formed image exhibiting a black color hue with such photoimage-forming materials, one possible method is to use an oxidizable leuco dye that exhibits a black color; Few compounds have been proposed, but xanthine compounds having an anilino group at the 2-position are known. (JP-A-61-137876) However, this xanthe compound having an anilino group at the 2-position has problems in terms of oxidation coloring property and coloring hue, and is not satisfactory.

It is also conceivable to use two or more types of oxidizable leuco dyes in combination to obtain black color, but in this case various problems regarding color mixing cannot be avoided.

OBJECT OF THE INVENTION Accordingly, an object of the present invention is to provide a heat-fixable photoimage-forming material with excellent stability of formed images and a black color hue.

"Means for Solving the Problem" The object of the present invention is to provide a photoimage-forming material in which a coating layer containing at least a leuco dye capable of oxidative color development, a photooxidizing agent, and a reducing agent is formed on a support. This was achieved using a photoimage-forming material characterized in that the leuco dye is a compound having an acrylic skeleton.

The leuco dyes which constitute a component of the photoimageable materials of this invention are reduced forms of dyes having one or two hydrogen atoms, the removal of which hydrogen atoms and the addition of additional electrons in some cases. Leuco dyes such as leuco dyes are substantially colorless or have a pale color, so when they oxidize and develop color, they become a means of forming a pattern.2. In the present invention, the oxidation is achieved by the presence of a photo-oxidizing agent.The second photo-oxidizing agent is activated by light irradiation and reacts with the leuco dye, producing a colored image only in the light-irradiated area. .

The leuco dye having an acridan skeleton and capable of developing color by oxidation according to the present invention is preferably substituted at the 9-position of the acridan skeleton. Particularly preferred are those substituted with an optionally substituted aromatic ring.

As the leuco dye having an acridan skeleton and capable of developing oxidative color according to the present invention, those represented by the following general formula ('I) are preferable.

(In the formula, R', R2 and R3 represent an alkyl group, an alkenyl group, an alkynyl group, an aryl group, and a hydrogen atom, and these may be the same or different, and R4, R1 and R
6 represents 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 halogen atom, a nitro group, or a cyano group. The acridan ring or the benzene ring at the 9-position thereof may have a plurality of the same or different substituents, and may be fused. ) In the above formula, the groups represented by RI SR2 and R3 further include an alkyl group, an alkenyl group, an alkynyl group, an aryl group,
Even if it is substituted with a hydrogen atom, a substituted amino group, an alkoxy group, an aryloxy group, an alkylthio group, a halogen atom, a nitro group, a cyano group, a substituted carbamoyl group, a substituted oxycarbamoyl group, a substituted oxysulfonyl group, a petero ring, etc. good.

These substituents may further have a substituent. Specifically, R1, Rz and R3 are -H, -CH3,
-Cn H2n-I Y Z s-"nH2n-'!A
YZ%-CnH2n-ms-(nH, nocmH2m-
1yz.

(n is an integer from 2 to -10, m is an integer from 1 to 5, Y and Z are 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 halogen atom, a nitro group, a cyano group, etc.) R1 and R2 may be bonded to each other to form a ring containing a hetero atom or an unsaturated bond, in which case, (1 is 4 to 7 , Y represents the above-mentioned group), etc. are preferred examples.

In formula (1), the groups represented by R4, R% and R6 are an alkyl group, an alkenyl group, an alkynyl group, an aryl group,
Substituted with hydrogen atom, substituted amino group, alkoxy group, aryloxy group, alkylthio group, norokene atom, nitro group, cyano group, substituted carbamoyl group, substituted oxycarbamoyl group, substituted oxysulfonyl group, heterocycle, etc. You can.

These substituents may further have a substituent.

The groups represented by R4, R8 and R6 are preferably an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a hydrogen atom, a halogen atom, an alkoxy group, or an aryloxy group, particularly a hydrogen atom, an alkyl group, a halogen atom,
An alkoxy group and a monoyloxy group are preferred.

Specifically, R', R' and R6 are hydrogen atom, methyl group, ethyl group, isopropyl group, butyl group, chlorine atom, bromine atom, trifluoromethyl group, benzyl group, methoxymethyl group, methoxy group, ethoxy group, propoxy group, etc. are preferred.

Next, specific examples relating to the present invention will be shown, but the present invention is not limited thereto.

9-(4-dimethylaminophenyl)-10-methylacridan, 9-(4-diethylaminophenyl)-
10-methylacridan, 9-(4-dibutylaminophenyl)-10-methylacridan/, 9-, (4
-diethylaminophenyl)-10-phenylacridan, 9-(4-diethylaminophenyl)-10-(
2-ethylhexyl)acridan, 9-(4-diethylaminophenyl)-10-benzylacridan, 9-
(4-dibutylaminophenyl)-10-octylacridan, 9-(4-diethylaminophenyl)-10
-methoxymethylacridan, 9-(4-dimethylamino-2-methylphenyl)-10-methylacridan, 9-(4-diethylamino-2-methylphenyl)
-10-methylacridan, 9-(4-diethylamine-2,6-dimethylphenyl)-10-(2-ethylhexyl)acritane, 9-(4-diethylaminophenyl)-1,8-dimethyl-10-phenyl Acridan, 9-(4-diethylaminophenyl)-1-methyl-
Examples include 10-phenylacridan, 9-(4-diethylamino-2-butylphenyl)-1O-(2-ethylhexyl)acridan, 9-7(4-diethylamino-2-ethoxyphenyl)-10-benzylacridan, etc. It will be done.

In addition to the above-mentioned compounds as leuco dyes according to the present invention,
The color Fl may be adjusted by using a material having another skeleton in combination. For example, US Patent No. 344
Preferred are those described in No. 5234.

Specifically, leuco crystal violet, tris-
(4-diethylamino-0-tolyl)-methane, bis-
(4-diethylamino-0-lyl)-phenylmethane, bis-<4-diethylamino-0-tolyl)-thienyl-2-methane, bis=(2-chloro-4-diethylaminophenyl)-phenylmethane, 2- (2-chlorophenyl)amino-6-N,N-dibutylamino-9(
2-methoxycarbonyl)-phenylxanthine, 2-
N,N-dibenzylamino-6-N,N-diethylamino-9-(2-methoxycarbonyl)-phenylxanthine, benzo(a]-6N,N-diethylamino-9-
(2-methoxycarbonyl)-phenylxanthine, 2
- (2-chlorophenyl)-amino-5-N, N-dibutylamino-9-(2-methylphenylcarboxamide)-phenylxanthine, 3.6-dimethoxy=9-
(2-methoxycarbonyl)-phenylxanthine, 3
．． Examples include 6-dinitoxyethyl-9-(2-methoxycarbonyl)-phenylxanthine, benzoylleucomethylene blue, 3.7-bis-diethylaminophenoxazine, and the like.

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.

Typical photo-oxidizing agents include 2゜4.5-1- as described in Japanese Patent Publication No. 62-39728, Japanese Patent Publication No. 63-2099, etc.
Lofine dimer compounds such as aryl imidazole dimers, azide compounds such as 2-azidobenzoxazole, benzoyl azide, and 2-azidobenzimidazole described in U.S. Pat. No. 3,282,693, U.S. Pat. No. 3,615
Pyridinium compounds such as 3'-ethyl-1-methoxy-2-pyridothiacyanine verchlorate, 1-methoxy-2methylpyridinium-p-)luenesulfonate described in No. 568, N-promosuccinimit, trifuromomethyl Phenylsulfone, 2-trichloromethyl-5
-(p-butoxystyryl)-1,3,4-oxadiazole, organic halogen compounds such as 2,6-dydolichloromethyl-4-(p-methoxyphenyl)-triazine,
Examples include the azide polymer described on page 55 of the lecture summary of the 1968 Spring Research Conference of the Photographic Society of Japan. Among these, lophine dimer compounds and organic halogen compounds are preferred, and the combination of both is optimal because high sensitivity can be achieved.

The molar ratio of the leuco dye to the photo-oxidizing agent in the photoimage-forming material of the present invention is preferably 10=1 to 1:10.
More preferably, the ratio is 2:1 to 1:5.

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

Specific examples of the reducing agent include hydroquinone compounds and aminophenol compounds that have a hydroxyl group on a benzene ring and at least another hydroxyl group or an amino group at another position on the benzene ring, as described in US Pat. No. 3,042,515;
Examples thereof include the cyclic phenylhydrazide compound described in No. 39728, and further compounds selected from guanidine derivatives, alkylene diamine derivatives, and hydroxyamine derivatives. These can be used alone or in combination of two or more, but are not limited to these as long as they are reducing substances that have the function of acting on so-called oxidizing agents.

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 1-100% based on the photooxidant component.
It is twice the molar amount, more preferably 2 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. It is preferable that a leuco dye, a leuco dye and a photo-oxidizing agent, or a reducing agent be included, and it is particularly preferable that a leuco dye and a photo-oxidizing agent be included.

A preferred capsule is one in which at room temperature, the material isolation effect of the microcapsule wall prevents contact between the materials inside and outside the capsule, and the permeability of the material 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 these, 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 reactant is added to the interior of the oil droplet and/or to the exterior of the oil droplet.

The specific method of microencapsulation is described in U.S. Patent No. 372.
No. 6804, No. 3796696, patent application No. 62-259
This is carried out by the method described in No. 111 and the like.

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 include biphenyls, alkylated terphenyls, alkylated naphthalenes, diarylethanes, and chlorinated paraffins.

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, isopropyl 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-) luenesulfonic 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, naphthoate Examples include aromatic sulfonic acid derivatives such as acids 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.

The above-mentioned microcapsules containing the leuco dye and photooxidizing agent and a dispersion of the reducing agent are combined with binders, pigments, waxes, metal soaps, surfactants, p-benzyloxyphenol, p-)luenesulfonamide, etc. to lower the melting point. Agents and acidic substances may be added, and the coating amount of the photoimage forming layer in the present invention is 3 to 30 g/m2 in terms of solid content, particularly 5.
~20 g/m 2 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 barcoding, 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 the coating layer contain a binder and/or a pigment as a main component.

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 is effectively achieved through contact between the photooxidizing agent and the reducing agent through the capsule wall by heating, but a synergistic effect can also be expected by applying heating and pressurization 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 photooxidant 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 performed using a thermal head, heat roller, heat stamp, hot plate, or the like.

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

Example 1 3 parts of 9-(4-diethylaminophenyl)-10-methylacridan, 2,2'-bis-(〇-chlorophenyl)-4,4', 5. 3 parts of 5'-tetraphenylbiimiguzole, 0.61 parts of tribromomethylphenylsulfone, 0.48 parts of 2.5-di-tert-octylhydroquinone and 75% by weight of xylylene diisocyanate/trimethylolpropane adduct in ethyl acetate. 24 parts of the solution was added to and dissolved in a mixed solvent of 22 parts of methylene chloride and 24 parts of tricresyl phosphate.

This solution was added to 63 parts of an 8% by weight aqueous solution of carboxy-modified polyvinyl alcohol and emulsified and dispersed at 20°C to obtain an emulsion with an average particle size of 1 μm. Add 1 part water to the resulting emulsion
00 parts were added and stirring continued at 40°C for 3 hours. Thereafter, the mixture was returned to room temperature and filtered to obtain a capsule dispersion.

Next, 30 parts of 1-phenylpyrazolidin-3-one (phenidone A) was added to 4 parts of carboxy-modified polyvinyl alcohol.
The mixture was added to 150 parts by weight of an aqueous solution and dispersed in a horizontal sand mill to obtain a phenidone 8 dispersion having an average particle size of 1 μm.

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

The above capsule dispersion The above phenidone A dispersion 20% silica (Thyroid 404, Fuji Davison Chemical Q
(manufactured by @) Dispersion 20 parts 30% epoxidized polyamide resin (FL-71, manufactured by Toho Chemical @)
15 parts 3% polyethylene glycol lauryl ether aqueous solution
Apply 10 parts of this coating solution to high-quality paper (basis weight 76 g/
m') with a coating rod, solid coating amount 10g/m2
The photoimage-forming material was obtained by coating and drying at 50°C.

This photoimage-forming material was irradiated with light using a jet light (ultra-high-pressure mercury lamp, OAK ■1!) through a line drawing original to obtain a clear black image.The sample after image formation was
The image was fixed by passing it through a heating roller at a temperature of 120C.

Thereafter, this sample was irradiated with light of five times the amount of image exposure using a jet light, but no change in the image was observed. Moreover, the obtained image had excellent stability.

Claims (1)

[Claims] A photoimage-forming material in which a coating layer containing at least a leuco dye capable of oxidative color development, a photooxidizing agent, and a reducing agent as essential components is formed on a support, characterized in that the leuco dye is a compound having an acridan skeleton. photoimageable material.