JPH07117693B2 - Photoimage forming material and image recording method using the same - Google Patents

Description

The present invention relates to a photoimageable material and an image recording method using the same.

More specifically, the present invention relates to a photoimageable material that can be used in applications such as proof paper, printout paper, and overlay film, and an image recording method using the same.

"Prior Art" Conventionally, this type of photoimage forming material has been used for many photographic applications as so-called free radical photography in which a light-sensitive portion is visualized by imagewise exposure.

Particularly effective in this regard is the method of radical oxidation of various leuco dyes to their corresponding dyes using photooxidants (eg Photo.Sci.Eng., 5 , 98-103).
(1961), JP-B-43-29,407, JP-A-55-55335,
See JP-A-57-60,329 and JP-A-62-66,254).

"Problems to be solved by the invention" However, since they are sensitive to light, when they are exposed to ordinary room light, sunlight or white light even after forming a dye image by exposure. Color formation occurs on the substrate and, therefore, the handling of such photoimageable materials is difficult.

In order to retain the image after it has been formed,
It must be avoided to develop color in the unirradiated area.
No Free radio by, for example, spraying or impregnation
Reducing agent solution such as cal trapping substance (hydroquinone etc.)
Preserves the original image by applying to the imaged material
It is known to do. This is the preservation of the original image or
Wet process, although advantageous for fixing
The complexity of workability and operability associated with passing through
Will be. Also, for example, Dylux from Du Pont like
Image formation with UV light, activity of photoreducing substance with visible light
It is possible to process with only the light that will fix the
Materials having the specified characteristics are commercially available. But Naga
In this process, the light was used twice
For the same time, and with it the spectral filter
It is necessary to change the
Has the disadvantage that processing speed is unsatisfactory
There is. Further, in the specification of Japanese Patent Publication No. 43-29,407,
Reducing in binder solution with leuco dye and photo-oxidizer
Of the heat fixing agent or the heat fixing agent is exposed to light.
If you heat-fix after image exposure by overcoating on the layer
There is such a description. However, these methods are currently
Actually fixed with the light-sensitive part (leuco dye and photo-oxidizer)
Since the agents coexist in close proximity, sensitivity deterioration with time
This is not good.

On the other hand, the photoimage forming material consisting of these leuco dyes and photooxidants is usually uniformly dissolved in an organic solvent and applied (or dipped, cast, etc.) on a support such as paper or plastic film, and the solvent is dried. To remove by evaporation. Therefore, it is necessary to take explosion-proof measures such as manufacturing facilities associated with the use of such a volatile organic solvent, which is disadvantageous in terms of safety and cost.

"Object of the Invention" The object of the present invention is to provide a photo-image forming material having high photosensitivity in addition to excellent image reproducibility, raw storability, and image storability (fixability), and further, the image forming and fixing It is to provide a completely dry and simple recording method in the process.

Another object of the present invention is to provide a photoimage forming material which reduces or eliminates handling in an organic solvent system which is disadvantageous in terms of production suitability.

"Means for Solving the Problem" The above-mentioned object of the present invention is that at least one kind selected from leuco dyes capable of oxidative coloring and at least two kinds selected from photo-oxidizing agents have the same material permeability by heating. Is contained in a microcapsule having a rising wall, and
At least one selected from a reducing agent is present on the outside of the microcapsules, and a photoimage forming material characterized by using a luffin dimer compound and an organic halogen compound in combination as a photo-oxidizing agent, The image recording method is characterized in that after the image is formed by irradiating the photoimage forming material with light, the photoimage forming material is heated to bring the photooxidizing agent and the reducing agent into contact with each other to perform fixing. .

The most characteristic feature of the photoimageable material of the present invention is that microcapsules are used and a specific photooxidant is used in combination.

The basic function of the microcapsule is as follows: (1) Each component can be microscopically separated inside and outside the microcapsule.

(2) By encapsulating something inside the microcapsule,
The influence of the external environment (especially moisture, oxygen, storage temperature, etc.) is reduced as much as possible, and the inclusions can be stored stably.

(3) If necessary, the contents inside or outside the capsule can be reacted by taking out the contents of the capsules by external stimulation (for example, heat or pressure) or by introducing the external additives into the capsules.

(4) Even if the core material of the capsule is an organic solvent system such as oil, the entire capsule dispersion system can be treated as an aqueous system.

Etc.

In the present invention, the functions (1) and (2) are used to improve the stability of the system, the functions (1) and (2) are used as a means of a simple recording method such as heat fixing after exposure, and (4)
Is used as an improvement in manufacturing suitability.

Also, the combined use of a specific photo-oxidizing agent brings out a synergistic effect which could not be expected by itself, and is utilized as an epoch-making high sensitivity technology.

The capsules preferred in the present invention prevent contact between substances inside and outside of the capsule at room temperature by the substance-separating action of the microcapsule wall, and the permeability of the substance increases only when heated above a certain temperature. 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 (eg, JP-A-59-91,438).
No. 59-190,886, Japanese Patent Application No. 59-99,490, etc.).

In order to control the glass transition temperature specific to the capsule wall, it is necessary to change the type of capsule wall forming agent. Examples of the microcapsule wall material that can be used in the present invention include polyurethane, polyurea, polyester, polycarbonate, urea-formaldehyde resin, melamine-
Examples thereof include formaldehyde resin, polystyrene, styrene-methacrylate copolymer, gelatin, polyvinylpyrrolidone, polyvinyl alcohol and the like. Also, two or more of these polymer substances can be used in combination.

In the present invention, among the above-mentioned polymer substances, polyurethane, polyurea, polyamide, polyester, polycarbonate and the like are preferable, and polyurethane and polyurea are particularly preferable.

The microcapsule used in the present invention is obtained by emulsifying a core substance containing a reactive substance such as a leuco dye and a photo-oxidizing agent, and then forming a wall of a polymer substance around the oil droplet to form a microcapsule. In this case, the high molecular substance forming reactant is added to the inside of the oil droplet and / or the outside of the oil droplet. Details of the microcapsules that can be preferably used in the present invention, such as the preferred method for producing the microcapsules, are described in US Pat.
No. 96,696.

For example, when polyurethane urea is used as a capsule wall material, a polyisocyanate and a second substance (for example, a polyol) which reacts with the polyisocyanate to form a capsule wall are mixed in an aqueous phase or an oily liquid to be encapsulated and then emulsified and dispersed in water. Then, by raising the temperature, a polymer forming reaction occurs at the oil drop interface to form a microcapsule wall. If the second additive is, for example, a polyamine or, if nothing is added, polyurea is formed.

In this case, regarding the polyisocyanate to be used and the partner polyol and polyamine that reacts with it, U.S. Pat. Nos. 2,181,383, 3,773,695, 3,793,268 and JP-B-48-4 are used.
0347, 49-24159, JP-A-48-80191, 48-84
No. 086, and they can also be used.

As the polyvalent isocyanate, for example, m-phenylene diisocyanate, p-phenylene diisocyanate,
2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl-diisocyanate, 3 ,
3'-Dimethyldiphenylmethane-4,4'-diisocyanate, xylylene-1,4-diisocyanate, 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene Diisocyanates such as -1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1,4-diisocyanate, 4,4 ', 4 "-triphenylmethane triisocyanate, toluene-2,4,6- Triisocyanates such as triisocyanates, tetraisocyanates such as 4,4'-dimethyldiphenylmethane-2,2 ', 5,5'-tetraisocyanates, adducts of hexamethylene diisocyanate and trimethylolpropane, 2,4-
There are isocyanate prepolymers such as tolylene diisocyanate and trimethylol propane adducts, xylylene diisocyanate and trimethylol propane adducts, and tolylene diisocyanate and hexane triol adducts.

Examples of polyols include aliphatic and aromatic polyhydric alcohols, hydroxypolyesters, and hydroxypolyalkylene ethers.

The following polyols described in JP-A-60-49991 can also be used. Ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,
6-hexanediol, 1,7-heptanediol, 1,8-
Octanediol, propylene glycol, 2,3-dihydroxybutane, 1,2-dihydroxybutane, 1,3-dihydroxybutane, 2,2-dimethyl-1,3-propanediol, 2,4-pentanediol, 2,5 -Hexanediol,
3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, dihydroxycyclohexane, diethylene glycol, 1,2,6-trihydroxyhexane,
2-phenylpropylene glycol, 1,1,1-trimethylolpropane, hexanetriol, pentaerythritol, pentaerythritol ethylene oxide adduct, glycerine ethylene oxide adduct, glycerin, 1,4-di (2-hydroxyethoxy) benzene, A condensation product of an aromatic polyhydric alcohol such as resorcinol dihydroxyethyl ether and an alkylene oxide,
p-xylylene glycol, m-xylylene glycol, α, α′-dihydroxy-p-diisopropylbenzene, 4,4′-dihydroxy-diphenylmethane, 2-
Examples thereof include (p, p′-dihydroxydiphenylmethyl) benzyl alcohol, an adduct of ethylene oxide with bisphenol A, and an adduct of propylene oxide with bisphenol A. Polyol is isocyanate group 1
It is preferable to use the hydroxyl group in an amount of 0.02 to 2 mol per mol.

Examples of polyamines include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, p-phenylenediamine, m-phenylenediamine, piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, and 2-hydroxytrimethylene. Diamine, diethylenetriamine, triethylenetriamine, triethylenetetramine, diethylaminopropylamine, tetraethylenepentamine,
Examples thereof include amine adducts of epoxy compounds. Polyisocyanates can also react with water to form polymeric substances.

Here, the organic solvent for forming the oil droplets can generally be appropriately selected from high-boiling point oils, and include phosphoric acid ester, phthalic acid ester, acrylic acid ester,
Methacrylic acid ester, other carboxylic acid ester,
Fatty acid amide, alkylated biphenyl, alkylated terphenyl, chlorinated paraffin, alkylated naphthalene,
Diarylethane or the like is used. Specifically,
Those described in 60-242,094 and Japanese Patent Application No. 62-75,409 can be used.

In the present invention, an auxiliary solvent may be added to the above organic solvent as a low boiling point dissolution aid. As such an auxiliary solvent, for example, ethyl acetate, isopropyl acetate, butyl acetate, methylene chloride and the like can be mentioned as particularly preferable ones.

On the other hand, the water-soluble polymer to be contained as a protective colloid in the aqueous phase mixed with the oil phase can be appropriately selected from known anionic polymers, nonionic polymers and amphoteric polymers. , Gelatin, cellulose derivatives and the like are preferable.

Further, as the surfactant to be contained in the aqueous phase, it is possible to appropriately select and use anionic or nonionic surfactants which do not cause precipitation or aggregation by acting on the protective colloid. . Preferable surfactants include sodium alkylbenzene sulfonate (for example, sodium lauryl sulfate), dioctyl sodium sulfosuccinate, polyalkylene glycol (for example, polyoxyethylene nonylphenyl ether) and the like.

In the present invention, the size of the microcapsules is 20 μm or less in terms of the volume average particle size according to the measuring method described in, for example, JP-A-60-214,990, particularly from the viewpoint of image resolution improvement, storability, and handleability. It is preferable that it is, and it is particularly preferable that it is 4 μm or less. If the capsule is too small, it may be erased in the pores of the substrate or in the fiber, but this cannot be said unconditionally because it depends on the nature of the substrate or support, but 0.1 µ or more is preferable.

Next, the leuco dye constituting one component of the photoimageable material of the present invention will be described. The leuco dye that can be used in the present invention is a reduction type dye having one or two hydrogen atoms and forming a dye by removing the hydrogen atom and adding an additional electron in some cases. Is included. Such leuco dyes are either substantially colorless or, in some cases, have a weak color and thus are a means of forming a pattern when oxidized and developed. This oxidation is achieved in the present invention by the presence of at least one photooxidant. The photo-oxidant is activated by irradiation with light and reacts with the leuco dye to produce a colored image against the back-irradiated and thus unaltered material background.

Leuco dyes which can be easily colored by oxidation by the above mechanism include those described in, for example, US Pat. No. 3,445,234, which is described here for reference.

(A) Aminotriarylmethane (b) Aminoxanthene (c) Aminothioxanthene (d) Amino-9,10-dihydroacridine (e) Aminophenoxazine (f) Aminophenothiazine (g) Aminodihydrophenyl Nadine (h) Aminodiphenylmethane (i) Leucoindamine (j) Aminohydrocinnamic acid (cyanoethane, leucomethine) (k) Hydrazine (l) Leucoin digoid dye (m) Amino-2,3-dihydroanthraquinone (n) ) Tetrahalo p, p'-biphenol (o) 2- (p-hydroxyphenyl) -4,5-diphenylimidazole (p) phenethylaniline Among these leuco dyes, those from (a) to (i) Becomes a dye by losing one hydrogen atom, but the leuco dyes from (j) to (p) To yield the parent dyes One of the hydrogen atom is lost. Of these, aminotriarylmethane is preferred. A generally preferred class of aminotriarylmethanes is that at least two of the aryl groups are (a) R ₁ and R ₂ are each hydrogen, and C ₁ -C
R ₁ R ₂ N-substituent in para position to the bond to the methane carbon atom, such as a group selected from ₁₀ alkyl, 2-hydroxyethyl, 2-cyanoethyl, or benzyl, and (b) lower alkyl (C is 1 to 4), lower alkoxy (C is 1 to 4), a phenyl group having a group ortho to the methane carbon atom selected from fluorine, chlorine, hydrogen or bromine; The aryl group may be the same as or different from the first two, and if different, (a) lower alkyl, lower alkoxy, chlorine, diphenylamino, cyano, nitro, hydroxy, fluorine or bromine, alkylthio, arylthio, thioester , Alkyl sulfone, aryl sulfone, sulfonic acid, sulfonamide, alkylamide, arylamide, etc. (B) amino, di-lower alkylamino, naphthyl that can be substituted with alkylamino; (c) pyridyl that can be substituted with alkyl; (d) quinolyl; (e) from indolinylidene that can be substituted with alkyl. It is a type of aminotriarylmethane and its acid salt characterized by being selected. Preferably R ₁ and R ₂ are hydrogen or alkyl of 1 to 4 carbon atoms. Most preferably all three aryl groups are the same.

The triarylmethane or other leuco dye having the above-mentioned structure causes a color-forming dark reaction which causes fog or coloring when applied to a photographic film, paper or other system as a conventional photoimage forming material. I may receive it.

However, these leuco dyes can be used in the novel material using the capsule of the present invention. because,
This is because the color-forming dark reaction can be prevented by having the capsule perform the same effect as storing such a composition in the absence of air.

On the other hand, at least two kinds of photo-oxidizing agents used in the photo-image forming material of the present invention are a loffin dimer compound and an organic halogen compound. These are inactive until exposed to gliding radiation such as visible rays, ultraviolet rays, infrared rays, and X-rays, but when exposed to light, an oxidizing agent that oxidizes the color forming agent to its colored form is formed. Occurs.

The loffin dimer compound is represented by the following formula. Upon dissociation, the dimer forms the corresponding 2,4,5-triarylimidazolyl group.

(Wherein A, B and D may be the same or different and unsubstituted or may be a carbocycle or heterocycle substituted with a substituent that does not inhibit the dissociation of the dimer to the imidazolyl group or the oxidation of the leuco dye) The groups B and D usually have 0 to 3 substituents and A
The group of has 0 to 4 substituents. Useful loffin dimer compounds and their preparation are disclosed in U.S. Pat. No. 3,552,973 at column 4, line 22 to column 6, line 3.

The chemical structural formulas of the loffin dimer compounds useful in the present invention are shown below, but the compounds usable in the present invention are not limited thereto.

.2,2'-bis- (o-chlorophenyl) -4,4 ', 5,5'
-Tetraphenyl biimidazole .2,2'-bis- (o-chlorophenyl) -4,4 ', 5,5'
-Tetrakis (m-methoxyphenyl) biimidazole .2,2'-bis- (o-trifluoromethylphenyl)
−4,4 ′, 5,5′-Tetraphenylbiimidazole -2- (2,3-dichlorophenyl) -4,5-bis- (3,4
-Methylenedioxyphenyl) -biimidazole The organic halogen compound used in combination with the above luffin dimer compound is a solid or liquid compound having 40 or less carbon atoms in the molecule. Specifically (1) General formula R-CX ₃ (wherein R is hydrogen, halogen, an aryl group, X is a halogen), a compound represented by, for example, carbon tetrachloride, carbon tetrabromide, p
-Nitrobayzotribromide, bromotrichloromethane, benzotrichloride, hexabromoethane, iodoform, 1,1,1-tribromo-2-methyl-2-propanol, 1,1,2,2-tetrabromoethane, 2 , 2,2-Tribromoethanol, 1,1,1-trichloro-2-methyl-
2-propanol, (2) general formula (In the formula, Rx represents hydrogen or 1 to 5 substituents on the benzene ring, and these substituents are a nitro group, a halogen group, an alkyl group, a haloalkyl group, an acetyl group, a haloacetyl group,
It is not necessary that all substituents are the same in the alkoxy group), for example, o-nitro-α, α, α-tribromoacetophenone, m-nitro-α, α, α-tribromo. Acetophenone, p-nitro-α, α, α-tribromoacetophenone, α, α, α-tribromoacetophenone, α, α, α-tribromo-3,4-cycloloacetophenone, (3) a compound represented by the general formula R-SO ₂ -X (wherein R is an alkyl group, X with an aryl group (including those having a substituent) is a halogen), such as 1,3-benzenedicarboxylic chloride, 2,4-dinitrobenzenesulfonyl chloride, o-nitrobenzenesulfonyl chloride, m-
Nitrobenzenesulfonyl chloride, 3,3'-diphenylsulfone disulfonis chloride, ethanesulfonyl chloride, p-bromobenzenesulfonyl chloride, p-nitrobenzenesulfonyl chloride, p-3
-Dobenzenesulfonyl chloride, p-acetamidobenzenesulfonyl chloride, p-chlorobenzenesulfonyl chloride, p-toluenesulfonyl chloride, methanesulfonyl chloride, benzenesulfonyl bromide, (4) General formula R-S-X (wherein R is an alkyl group) , An aryl group (including those having a substituent), X is a halogen), for example, 2,4-dinitrobenzenesulfenyl chloride, o-nitrobenzenesulfenyl chloride, (5) General formula Or (Wherein R is a substituted or unsubstituted aryl group, heterocyclic ring residues are X ₁ , X ₂ , and X ₃ are hydrogen, and halogen is not all hydrogen at the same time), for example, hexabromo Dimethyl sulfoxide, pentabromodimethyl sulfoxide,
Hexabromodimethyl sulfone, trichloromethylphenyl sulfone, tribromomethylphenyl sulfone, trichloromethyl-p-chlorophenyl sulfone, tribromomethyl-p-nitrophenyl sulfone, 2-trichloromethylbenzothiazole sulfone, 4,6-dimethyl Pyrimidine-2-tribromomethyl sulfone, tetrabromodimethyl sulfone, 2,4-dichlorophenyl-trichloromethyl sulfone, 2-methyl-4-chlorophenyl-trichloromethyl sulfone, 2,5-dimethyl-4-
Chlorophenyl-trichloromethyl sulfone, 2,4-dichlorophenyl-tribromomethyl sulfone, (6) General formula (Wherein R is a heterocyclic compound residue which may have a substituent. X ₁ , X ₂ and X ₃ are hydrogen or halogen and are not all hydrogen at the same time), for example, Tribromoquinaldine, 2-
Tribromomethyl-4-methylquinoline, 4-tribromomethylpyrimidine, 4-phenyl-6-tribromomethylpyrimidine, 2-trochloro-methyl-6-nitrobenzothiazole, 1-phenyl-3-trichloromethylpyrazole, 2 , 5-Ditribromomethyl-3,4-dibromothiophene, 2-trochloromethyl-5- (p-butoxystyryl) -1,3,4-toxadiazole, 2,6-ditrichloromethyl-4- And organic halogen compounds such as (p-methoxyphenyl) -troazine.

Among these, the compounds of (2), (5) and (6) are preferable, and as the halogen, chlorine, bromine and iodine are preferable.

In producing the photoimageable material of the present invention, good results are obtained by mixing the leuco dye and the photooxidant in a molar ratio of about 10: 1 to about 1:10. More desirable ratio is 2: 1
Or 1: 2.

In addition, the combination ratio of the two photo-oxidizing agents is a luffin dimer compound.
With respect to 10 mol, 0.05 to 100 mol of an organic halogen compound,
It is preferably 0.2 to 10 mol.

The photoimage forming material of the present invention can be exposed to light to form an image, and then, for example, to be subjected to heat treatment, whereby a stable image can be reliably obtained. That is, as a mechanism for fixing the photoimageable material of the present invention, for example, by contacting the photooxidizing agent and the reducing agent through the capsule wall by heating, the reducing agent can be activated even if the photooxidizing agent is no longer activated thereafter. This is because it acts to deactivate the oxidant.

Such reducing agents typically act as so-called free radical scavengers that trap the free radicals of the activated photooxidant.

As such a free radical scavenger, all known substances can be used, and specifically, the following substances are included.

For example, an organic reducing agent having a hydroxyl group on the benzene ring described in US Pat. No. 3,042,515 and at least another hydroxyl group or an amino group at another position of the benzene ring (for example,
Hydroquinone, catechol, resorcinol, hydroxyhydroquinone, pyrologricinol and aminophenols such as o-aminophenol, p-aminophenol, etc.) or the cyclic phenylhydrazide described in the specification of JP-B-62-39,728. Compound, eg 1-
Phenylpyrazolidin-3-one [Phenidone A, the following formula (1)], 1-phenyl-4-methylpyrazolidin-3-one [Phenidone B, the following formula (2)], 1-phenyl -4,4-Dimethylpyrazolidin-3-one [dimesone, the following formula (3)] or 3-methyl-1- (p-
Sulfophenyl) -2-pyrazolin-5-one and 3-
Methyl-1-phenyl-2-pyrazolin-5- You can turn it on.

However, the following substituents may be present on the phenyl group of the cyclic phenylhydrazide. O-, m- and p-methyl, p-trifluoromethyl, m- and p-chloro, m- and p-bromo, p-fluoro, o-, m-
And p-methoxy, p-ethoxy, p-benzyloxy, p-butoxy, p-phenoxy, 2,4,6-trimethyl, 3,4-dimethyl. The following substituents can be present at the 4-position on the heterocyclic group of the cyclic phenylhydrazide.
Bis-hydroxymethyl, hydroxymethyl and methyl,
Hydroxymethyl, dimethyl, dibutyl, ethyl, benzyl. The following substituents may be present at the 5-position on the heterocyclic group of the cyclic phenylhydrazide: dimethyl, methyl, phenyl.

Furthermore, guanidine derivatives, alkylenediamine derivatives,
A compound selected from hydroxyamine derivatives can be used. Specifically, as the guanidine derivative,
For example, phenylguanidine, 1,3-diphenylguanidine, 1,2,3-triphenylguanidine, 1,2-dicyclohexylguanidine, 1,2,3-tricyclohexylguanidine, 1,3-di-o-tolylguanidine , O-tolyldiphenylguanidine, m-tolyldiphenylguanidine, p-tolyldiphenylguanidine, N, N′-dicyclohexyl-4-morpholinocarboxamidine, 1,3
-Ditolyl-3-phenylguanidine, 1,2-dicyclohexylphenylguanidine, 1-o-tolylbiguanide, N-benzylidene-guanidinoamine and the like.

Examples of the alkylenediamine derivative include ethylenediamine, propylenediamine, tetramethylenediamine, hexamethylenediamine, octamethylenediamine, 1,1,2-diaminododecane and tetrabenzylethylenediamine.

Examples of the hydroxyamine derivative include diethanolamine, triethanolamine, 3-β-naphthyloxy-1-N, N dimethylamino-2-propanol and the like.

The reducing agents used in combination as the above free radical scavenging substances can be used alone or in combination of two or more kinds, but are not limited to these as long as they are reducing substances having a function capable of acting on so-called oxidizing agents. is not.

In the photo-image forming material of the present invention, the leuco dye and the photo-oxidizing agent are both encapsulated in microcapsules, but the reducing agent not encapsulated is either solid-dispersed by a sand mill or after being dissolved in oil. It is preferable to use by emulsifying and dispersing.

In the case of solid dispersion, it is dispersed in a water-soluble polymer solution having a concentration of 2 to 30% by weight, and a preferable dispersed particle size is 10 μm or less. Preferred water-soluble polymers include water-soluble polymers used when making microcapsules. The emulsification / dispersion can be carried out by referring to the methods and materials described in the specification of Japanese Patent Application No. 62-75,409.

The preferred amount of reducing agent is from 1 to 10 on a molar basis of the photooxidant component.
Although it can be used in a 0-fold molar amount, a range of 1- to 10-fold molar amount is more preferable in order to obtain a desired result in the smallest possible amount.

Furthermore, in order to impart a fixing property to the photoimage forming material composed of a leuco dye capable of oxidative coloring and a photo-oxidizing agent, the reducing agent alone or the reducing agent in the embodiment of the present invention may be encapsulated in microcapsules. It is possible.

In the present invention, a known sensitizer may be added and used as an additional component of the photo-oxidizing agent. For example, the compounds described in “Sensitizer” by Katsumi Tokumaru and Shin Okawara, pp. 64-75 in Kodansha 1987 can be mentioned. Specifically, aromatic ketones, acetophenones, diketones, carbonyl compounds such as acyloxime esters, aromatic thiols, mono- and disulfides, sulfur compounds such as thioureas and dithiocarbamates, and benzoyl peroxide. Examples thereof include organic peroxides, azo compounds such as azobisisobutyronitrile, and halides such as N-bromosuccinimide. Further, as a sensitizing dye in the visible region, an amidinium ion system described on pages 160 to 123 of the same book,
Examples thereof include a dye having a carboxyl ion type or dipolar amide type chromophore. Specifically, cyanine-based, phthalein-based, and oxonol-based dyes are typical.

In the present invention, a known stabilizer such as an antioxidant may be added to the capsule for use. The function of the stabilizer here is, of course, a substance having a function similar to that of the reducing agent, although the purpose of use is different. Therefore, specifically, in addition to the above-mentioned free radical scavenger, the compounds described in U.S. Pat. No. 4,066,459 or JP-A-55-5
2,4-dihydroxyaldoxime and the like described in the specification of No. 5,335 can be mentioned, and the amount of the stabilizers used is from about 0.01 mol% to about 25 mol% based on the photo-oxidizing agent.
Is used preferably in the range of 0.1 mol% to 10 mol%.

The photo-image forming material in the present invention can be prepared by coating, impregnating or forming a self-supporting layer on a support as a dispersion of microcapsules containing such a leuco dye and a photo-oxidizing agent and a reducing agent.

At this time, as a binder that can be added to the dispersion, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, gum arabic, gelatin, polyvinyl pyrrolidone, casein, styrene-butadiene latex, acrylonitrile-butadiene latex, polyvinyl acetate. Various emulsions such as polyacrylic acid ester, ethylene-vinyl acetate copolymer and the like can be used. The amount is in terms of the solid content ^{0.5g / m 2 ~5g / m 2} .

The coating amount of the photoimage forming material in the present invention is calculated in terms of solid content.
^{3g / m 2 ~30g / m 2} , it is preferable that particularly is between ^{5g / m 2 ~20g / m 2} . Sufficient concentration was not obtained below 3 g / m ² and 30 g / m ²
Even if the above coating is performed, no improvement in quality is seen, which is disadvantageous in cost.

Suitable materials for the support include papers from tissue paper to thick cardboard, regenerated cellulose, cellulose acetate, cellulose nitrate, polyethylene terephthalate, vinyl polymers and copolymers, polyethylene, polyvinyl acetate, polymethylmethacrylate. , Films of plastics and polymeric materials such as polyvinyl chloride; woven fabrics; materials commonly used in graphic arts and decorative applications such as glass, wood and metal.

For coating the support, generally well-known coating methods, for example, day coat method, air knife coat method, curtain coat method, roller coat method, doctor coat method, wire bar coat method, slide coat method, gravure coat Method, spin coating method or US Patent No. 2,
It can be applied by an extrusion coating method using a hopper described in the specification of No. 681,294.

In the present invention any convenient light source can be used to activate the photooxidant and image the leuco dye. Irradiation can be natural or artificial, monochromatic or non-coherent or coherent light, and must be sufficiently dense for activation of the appropriate photoimageable composition.

Conventional light sources include fluorescent lamps, mercury, metal additions and arc lamps. Coherent light sources are pulsed nitrogen-lasers, xenon lasers, argon ion-lasers and ionized neon lasers whose emission is within or overlaps the UV or visible absorption band of the photooxidant. . The UV and near visible light irradiation-luminescent cathode ray tubes that are widely used in printout systems for writing on light sensitive materials are also useful in the subject compositions.

The image may be formed by writing with a beam of activating light or by exposing selected areas of the back of a negative, stencil or other relatively opaque pattern with such light. The negative may be silver on a film of cellulose acetate or polyester or such that its opacity occurs due to the agglomeration of regions having different refractive indices. Image formation may also be carried out in conventional diazo printing machines, graphic art exposure or electronic flash machines, and also by the procedures described in US Pat. No. 3,661,461. The exposure time is between a fraction of a second and a few minutes, depending on the density of light and the spectral energy distribution, its distance from the composition, the nature and amount of the composition used, and the density of color in the desired image. May change.

After the image exposure, the image can be fixed by bringing the photo-oxidizing agent and the reducing agent into contact with each other. Various methods can be applied to bring them into contact with each other.

For example, there is a method of heating. In this method, by raising the temperature of the microcapsule wall to a temperature above its glass transition point, the photo-oxidizing agent and the reducing agent pass through the wall of the softened microcapsule and come into contact with each other. The glass transition point of the microcapsule wall depends on the material used, and therefore the heat treatment conditions necessary for fixing can be appropriately selected in consideration of these.

The photoimage forming material of the present invention is used as a photoimage forming composition which is excellent in production suitability, and is excellent in image forming property and storability.
Examples will be shown below, but the present invention is not limited thereto. In addition, "part" which shows addition amount shows a "weight part."

"Example" Example 1 The following photoimageable materials were prepared.

Sample (1): Leuco dye Leuco Crystal Violet 3.0 parts Photo-oxidant 2,2'-bis- (o-chlorophenyl)
-4,4 ', 5,5'-Tetraphenylbiimidazole 3.0 parts Tribromomethylphenyl sulfone 0.6 parts Methylene chloride 22 parts Tricresyl phosphate 24 parts Takenate D-110N (75 wt% ethyl acetate solution (Takeda Yakuhin) 24 parts by trade name (manufactured by Kogyo Co., Ltd.) are mixed and added to an aqueous solution consisting of 63 parts of an aqueous solution of 8% by weight polyvinyl alcohol and 100 parts of distilled water, and then emulsified and dispersed at 20 ° C to obtain an average particle size of 1 µm. The obtained emulsion was continuously stirred for 3 hours at 40 ° C. Then, the mixture was returned to room temperature and filtered to obtain an aqueous capsule dispersion.

Next, polyvinyl alcohol 4% by weight aqueous solution 150 parts Reducing agent 1-phenylpyrazolidin-3-one (phenidone A) 30 parts were mixed, and Dynomil (Willie A. Bakoven.
Dispersed by AJ (trade name), average particle size 3μ
A phenidone A dispersion liquid was obtained.

9 parts of the above capsule liquid and 6 parts of phenidone A dispersion liquid were mixed, and coated on a super calendered high-quality paper (basis weight of 64 g / m ² ) so as to have a solid coating amount of 10 g / m ² , and at 50 ° C., 1 It heat-dried for 1 minute and obtained the sample (1).

Comparative Examples 1 and 2 2,2'-bis- (o-chlorophenyl) as a photo-oxidizing agent
Sample (2) was prepared in the same manner as in Example 1 except that 3,6 parts of 4,4 ', 5,5'-tetraphenylbiimidazole or 3,6 parts of tribromomethylphenyl sulfone were used, respectively (2),
A sample (3) was prepared.

For these samples (1) to (3), a jet light (super high pressure mercury lamp, Oak Co., Ltd.)
Light), and the reflection density in the visible region of the exposed area was measured with a Macbeth RD-918 type densitometer. The results are shown in Table 1.

From these results, the combined use of the two specific photo-oxidizing agents of the present invention brings out a synergistic effect which cannot be expected by themselves because the exposure dose of light irradiation for obtaining a constant exposure concentration is extremely small. It can be seen that epoch-making high sensitivity was achieved.

Next, the sample (1) after the image formation was heated at a temperature of 120 ° C.
(By dynamic viscoelasticity measurement, pass through a heating roller of about 20 ° C higher than the glass transition temperature of the capsule wall) at a speed of 450 mm / min to promote the permeability of the capsule wall due to heat and to fix it (for the inside and outside of the capsule). Contact). Formation, and then this sample was exposed to a jet light at 5
No change in the image was observed despite the double irradiation of the entire surface.

From the above results, it can be seen that the photoimageable material of the present invention has excellent image reproducibility and image storability (fixability).

Example 2 Of the photo-oxidants, doribromomethylphenyl sulfone 0,
A sample was prepared in the same manner as in Example 1 except that 0,3 parts of 2-trichloromethyl-5- (p-butoxystyryl) -1,3,4-oxadiazole was used instead of 6 parts.

When this sample was irradiated with light through a line drawing original document with a jet light at an exposure amount of 20 counts, a clear color image with a reflection density of 1.15 was obtained.

Next, the sample after the image formation was subjected to the same fixing operation as in Example 1 and then to the same whole surface light irradiation, but no change in the image was observed.

Example 3 Leuco crystal violet 3.0 as leuco contact
3.0 parts of tris- (2-methyl-4-diethylaminophenyl) -methane was used in place of the parts, and 2,6-ditrichloromethyl-4- (in place of 0.6 parts of tribromomethylphenylsulfone among the photo-oxidizing agents. A sample was prepared in the same manner as in Example 1 except that 3.0 parts of p-methoxyphenyl) -triazine was used.

When this sample was irradiated with light through a line drawing original document with a jet light at an exposure amount of 100 counts, a clear color image with a reflection density of 1.38 was obtained.

Next, the sample after the image formation was subjected to the same fixing operation as in Example 1 and then to the same whole surface light irradiation, but no change in the image was observed.

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Claims (2)

[Claims] 1. At least one kind selected from leuco dyes capable of oxidative coloring and at least two kinds selected from photo-oxidizing agents are both encapsulated in microcapsules having a wall whose permeability to a substance is increased by heating. And, in the photoimage forming material in which at least one selected from a reducing agent is present outside the microcapsules, the photooxidizing agent is selected from loffin dimer compounds represented by the following general formula. At least one (Wherein A, B and D may be the same or different and unsubstituted or may be a carbocycle or heterocycle substituted with a substituent that does not inhibit the dissociation of the dimer to the imidazolyl group or the oxidation of the leuco dye) Representing a group) At least one selected from the organic halogen compounds represented by the following general formulas (1) to (6) is represented by the general formula (1) R-CX ₃ (wherein R is hydrogen, halogen or an aryl group). , X is a halogen) General formula (2) (In the formula, Rx represents hydrogen or 1 to 5 substituents on the benzene ring, and these substituents are a nitro group, a halogen group, an alkyl group, a haloalkyl group, an acetyl group, a haloacetyl group,
It is not necessary that all the substituents are the same in the alkoxy group. General formula (3) R—SO ₂ —X (wherein R is an alkyl group, an aryl group (including those having a substituent), and X is a halogen). ) General formula (4) R-S-X (wherein R is an alkyl group, an aryl group (including those having a substituent) and X is a halogen) General formula (5) Or (Wherein R is a substituted or unsubstituted aryl group, heterocyclic ring residues are X ₁ , X ₂ , and X ₃ are hydrogen, and halogen is not all hydrogen at the same time) General formula (6) (In the formula, R is a heterocyclic compound residue which may have a substituent. X ₁ , X ₂ and X ₃ are hydrogen and halogen, and not all of them are hydrogen at the same time.) Lophine dimer compound 10 mol On the other hand, an optical image-forming material characterized by being used in an amount of 0.05 to 100 mol of an organic halogen compound. 2. At least one selected from leuco dyes capable of oxidative coloring and at least two selected from photo-oxidizing agents are both encapsulated in microcapsules having a wall whose permeability to a substance is increased by heating. And, in the photoimage forming material in which at least one selected from a reducing agent is present outside the microcapsules, the photooxidizing agent is selected from loffin dimer compounds represented by the following general formula. At least one (Wherein A, B and D may be the same or different and unsubstituted or may be a carbocycle or heterocycle substituted with a substituent that does not inhibit the dissociation of the dimer to the imidazolyl group or the oxidation of the leuco dye) Representing a group) At least one selected from the organic halogen compounds represented by the following general formulas (1) to (6) is represented by the general formula (1) R-CX ₃ (wherein R is hydrogen, halogen or an aryl group). , X is a halogen) General formula (2) (In the formula, Rx represents hydrogen or 1 to 5 substituents on the benzene ring, and these substituents are a nitro group, a halogen group, an alkyl group, a haloalkyl group, an acetyl group, a haloacetyl group,
It is not necessary that all the substituents are the same in the alkoxy group. General formula (3) R—SO ₂ —X (wherein R is an alkyl group, an aryl group (including those having a substituent), and X is a halogen). ) General formula (4) R-S-X (wherein R is an alkyl group, an aryl group (including those having a substituent) and X is a halogen) General formula (5) Or (Wherein R is a substituted or unsubstituted aryl group, heterocyclic ring residues are X ₁ , X ₂ , and X ₃ are hydrogen, and halogen is not all hydrogen at the same time) General formula (6) (In the formula, R is a heterocyclic compound residue which may have a substituent. X ₁ , X ₂ and X ₃ are hydrogen and halogen, and not all of them are hydrogen at the same time.) Lophine dimer compound 10 mol With respect to the organic halogen compound is used in an amount of 0.05 to 100 moles in combination with the photo-image forming material after image formation by irradiation with light, the photo-image forming material is heated to the photo-oxidizing agent and the reducing agent. An image recording method characterized by contacting and fixing.