JPH03120538A - Material for forming optical image - Google Patents

Abstract

PURPOSE:To enhance stability of a leuco-compound and to convert a dye image into a magenta color image by using a specified leuco-dye. CONSTITUTION:This optical image forming material is obtained by forming on a support a coating layer composed essentially of the leuco-dye capable of developing color by oxidation, a photooxidizing agent, and a reducing agent, and as the dye, bis(indolyl)arylmethane compound, such as a compound of formula I in which each of R<1> and R<2> is H, alkyl, aralkyl, or the like; each of R<3> and R<4> is H, alkyl aryl, or the like; and Ar is an aromatic ring. The compound of formula I can be embodied by bis(1-octyl-2-methyl-3-indolyl)-(2- methoxycarbonylphenyl)me-thane and the like.

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 leuco stability and a magenta coloring hue.

"Prior Art" Conventionally, photoimageable materials that can be used for applications such as proofing 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 a method in which various leuco dyes are oxidized and colored into corresponding dyes using a photo-oxidizing 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 of Japanese Patent Publication No. 43-29407 describes a method in which image formation is performed using UV light and fixing is performed by activating a photoreducing substance with visible light, and Japanese Patent Publication No. 43-29407 describes a method in which image formation is performed using UV light and fixation is performed by activating a photoreducing substance. A method has been proposed in which the compound is contained in the layer or coated on the photosensitive layer, and the image is thermally fixed after exposure.

Among the leuco dyes used in such photoimage-forming materials, many of the bisindolylarylmethane compounds that exhibit a magenta hue develop color over time due to their unstable leuco form, and improvements in stability are desired. was.

``Object of the Invention'' Therefore, an object of the present invention is to provide a heat-fixable photoimage-forming material that has excellent leuco stability and a magenta coloring hue.

An object of the present invention is to provide a photoimage-forming material in which a coating layer containing a leuco dye capable of forming oxidative color, a photooxidizing agent, and a reducing agent as essential components is formed on a support. This was achieved by a photoimage-forming material characterized in that the leuco dye is a bisindolylarylmethane compound.

The leuco dye constituting a component of the photoimageable material of the present invention is a reduced form of a dye having one or two hydrogen atoms;
Removal of the hydrogen atom and, in some cases, addition of additional electrons develops color to form a dye. Since such leuco dyes are substantially colorless or have a light color, when oxidized and colored, they serve as a means for forming a pattern. This oxidation is achieved in the present invention by the presence of a photooxidizing agent. This photooxidizing agent is activated by light irradiation and reacts with the leuco dye, producing a colored image only in the light irradiated area.

Among the leuco dyes having a bisindolylarylmethane skeleton and capable of forming oxidative color according to the present invention, those in which the aryl group has a substituent at the 2-position with respect to the methyl group are particularly stable in their leuco form. Yes, it is preferable.

As the leuco dye having a bisindolylmethane skeleton and capable of developing oxidative color according to the present invention, those represented by the following formula (1) are preferable.

(In the formula, R1 and R1 represent a hydrogen atom, an alkyl group, an aralkyl group, or an alkyl group, and these may be the same or different; R1 and R4 are a hydrogen atom, an alkyl group,
It represents an aryl group, which may be the same or different, and Ar represents an aromatic ring substituted at the 2-position relative to the methyl group. The indole ring or Ar may have a plurality of the same or different substituents, and may be fused.

) In the above formula, the groups represented by RI and R' are preferably a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and these groups further have a substituent. Good too. Particularly preferred are alkyl groups having 1 to 8 carbon atoms and aryl groups having 6 to 10 carbon atoms.

In the above formula, the groups represented by R1 and R4 are preferably a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to IO carbon atoms, and these may further have a substituent. Particularly preferred are alkyl groups having 1 to 6 carbon atoms.

etc. are preferred examples.

The aromatic ring represented by Ar in the above formula is preferably an aromatic ring which may contain a hetero atom having 5 to 20 carbon atoms, and particularly may contain a hetero atom having 5 to IO carbon atoms. Aromatic rings are preferred. Specifically, a benzene ring, a naphthalene ring, a pyridine ring, and a pyrimidine ring are preferred.

The substituent at the 2-position of Ar is an alkyl group, an aryl group,
Preferred are substituted amino groups, alkoxy groups, aryloxy groups, alkylthio groups, halogen atoms, nitro groups, cyano groups, trifluoromethyl groups, alkoxycarbonyl groups, carbamoyl groups, and the like. These may further have a substituent. In particular, alkyl groups having 1 to 4 carbon atoms, alkoxy groups having 1 to 4 carbon atoms, fluorine atoms, chlorine atoms,
Bromine atom, trifluoromethyl group, number of carbon atoms 2-20
An alkoxycarbonyl group and a carbamoyl group having 1 to 10 carbon atoms are preferred.

The substituent at the 2-position of Ar may be fused with Ar to form a ring.

Ar may have one to more substituents, and these may be the same or different.

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

Bis(l-octyl-2-methyl-3-indolyl)-
(2,6-dimethylphenyl)methane, bis(l-ethyl-2-methyl-3-indolyl)-(l-naphthyl)
Methane, bis(l-ethyl-2-methyl-3-indolyl)-(2,4,6-drimethylphenyl)methane, bis(1-ethyl-2-methyl-3-indolyl)-(2
,6-dichlorophenyl)methane, bis(l-hexyl-2-methyl-3-indolyl)-(2,5-dimethoxyphenyl)methane, bis(l-ethyl-2-methyl-
3-indolyl)-(2-methoxycarbonylphenyl)methane, bis(1-ethyl-2-methyl-3-indolyl)-(2-(2-ethylhexyl)oxycarbonylphenyl)methane, bis(1-phenyl-2 -Methyl-3-indolyl)-(1-naphthyl)methane, bis(l-phenyl-2-methyl-3-indolyl)-(2
,6-dichlorophenyl)methane, bis(1-phenyl-2-methyl-3-indolyl)-(2-ethoxycarbonylphenyl)methane, bis(1-(4-octyloxyphenyl)-2-methyl-3 -indolyl)-(2
-methoxycarbonylphenyl)methane, bis(l-phenyl-2-methyl-3-indolyl) -(2-(p
-methoxyphenoxy-2-propyl)oxycarbonylphenyl)methane, (l-phenyl-2-methyl-
3-indolyl)-(l-octyl-2-methyl-3-
Examples include indolyl)-(2-methoxycarbonylphenyl)methane.

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

Specifically, leuco crystal violet, tris-
(4-diethylamino-〇-tolyl)-methane, bis-
(4-diethylamino-0-lyl)-phenylmethane, bis-(4-diethylamino-0-lyl)-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)-6-N,N-diethylamino-9
-(2-methoxycarbonyl)-phenylxanthine,
2-(2-chlorophenyl)-amino-6-N,N-
Dibutylamino-9-(2-methylphenylcarboxamide)-phenylxanthine, 3,6-simethoxy 9
-(2-methoxycarbonyl)-phenylxanthine,
Examples include 3,6-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 lophine dimer compounds such as 2゜4.5-triarylimidazole dimer described in Japanese Patent Publication No. 62-39728 and Japanese Patent Publication No. 63-2099, etc.; Azide compounds such as 2-azidobenzoxazole, benzoyl azide, 2-azidobenzimidazole, US Pat. No. 36,155
3°-ethyl-1-methoxy-2-pyridothiacyanine verchlorate described in No. 68, pyridinium compounds such as l-methoxy-2-methylpyridinium-p-toluenesulfonate, N-promosuccinimide, tribromomethylphenyl Sulfone, 2-trichloromethyl-5-
Organic halogen compounds such as (p-butoxystyryl)-1,3,4-oxadiazole, 2,6-dydolic p-promethyl-4-(p-methoxyphenyl)-triazine, 1968 Spring Research Presentation of the Photographic Society of Japan Examples include the azide polymer described on page 55 of the lecture 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.

The molar ratio of the leuco dye to the photooxidizing agent in the photoimage-forming material of the present invention is preferably 1:1 to 1:10, more preferably 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 preferable amount of reducing agent is 1 to 100% relative to the photooxidation side 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. As the protective colloid, water-soluble polymers can be used for boat fishing, 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.

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, □The coating amount of the photoimage forming layer in the present invention is 3 to 30 g/m in terms of solid content.
"s, especially 5 to 20 g/m richness 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 can be effectively achieved by bringing the photooxidizing agent and reducing agent into contact through the capsule wall by heating, but a synergistic effect can also be expected by applying heating and pressurization simultaneously.

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 "r parts" indicating the amount added indicates "parts by weight."

Example 1 Bis(1-octyl-2-methyl-3-indolyl)-
3 parts of (2-methoxycarbonylphenyl)methane, 2.
2-bis-(0-chlorophenyl)-4,4,5,5
- 3 parts of tetraphenylbiimidazole, 0.6 part of tribromomethylphenylsulfone, 0.4 part of 2,5-di-tert-octylhydroquinone and a 75% by weight solution of xylylene diisocyanate/trimethylolpropane adduct in ethyl acetate 24 parts were added to a mixed solvent of 22 parts of methylene chloride and 24 parts of tricresyl phosphate and dissolved. 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. 100 parts of water was added to the obtained 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, 30 parts of l-phenyl, pyrazolidin-3-one (phenidone A) was added to 150 parts of a 4% by weight aqueous solution of carboxy-modified polyvinyl alcohol and dispersed in a horizontal sand mill to obtain a phenidone A dispersion with an average particle size of 1 μm. Obtained.

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 ■
(manufactured by) Dispersion liquid 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 at a solid coating weight of 10 g/m'' and dried at 50°C to obtain a photoimage-forming material.

This photoimage-forming material was irradiated with light through a line drawing original using a jet light (ultra-high pressure mercury lamp, manufactured by Oak ■) to obtain a clear magenta image.

After image formation, the sample was passed through a heated roller at a temperature of 120 C to perform fixing. 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.

Example 2.3 The bis(1-octyl-2-methyl-3-indolyl)-(2-methoxycarbonylphenyl)methane of Example 1 was converted into bis(1-phenyl-2-methyl-3-indolyl)-( 2,6 dichlorophenyl)methane (Example 2), bis(l-ethyl-2-methyl-3-indolyl)-
(2-ethoxycarbonylphenyl)methane (Example 3
), except that the same operations as in Example 1 were performed to obtain a clear magenta image. After the image-formed sample was fixed in the same manner as in Example 1, the entire surface was irradiated with light, but no change in the image was observed.

In addition, the obtained images had excellent stability.

Ma

Claims (1)

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