JPH01279239A - Heat development type copying material - Google Patents

Abstract

PURPOSE:To improve the transparency of the material and to obtain high color forming densities even by low temp. development by incorporating a diazo compd. into microcapsules and dissolving a coupling component in an org. solvent which is hardly soluble or insoluble in water and allowing the soln. to exist in the form of very small oil drops. CONSTITUTION:The diazo compd., the coupling component and a color forming assistant are incorporated on a high-polymer base. Namely, the diazo compd. is incorporated into the microcapsules and the coupling component is dissolved in the org. solvent which is hardly soluble or insoluble in water. The soln. thereof is made to exist in the form of very small oil drops. The microcapsules to be used are formed by using the soln. prepd. by dissolving a diazonium salt and the same kind or different kinds of the compds. which form a high-polymer material by reacting with each other into a nonaq. solvent having 40-95 deg.C b. p. under the atm. pressure. Said capsules contain substantially no solvent. The transparency is thereby improved and the high color forming density is obtd. even by the low-temp. heat development. The material is thus usable as the cause for high quality.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a copying material in which a diazo compound (diazonium salt) is encapsulated in microcapsules, and particularly to a copying material with excellent transparency.

<Prior Art> There are three types of copying materials that utilize the photosensitivity of diazo compounds. One type is known as a wet development type, in which a photosensitive layer containing a diazo compound and a coupling component as main components is provided on a support.
This material is superimposed on the original, and after exposure, it is developed with an alkaline solution. The second type is known as a dry development type, which, unlike the wet type, develops with ammonia gas. The third type is known as a heat-developable type, and includes a type that contains an ammonia gas generating agent such as urea that can generate ammonia gas when heated in the photosensitive layer, or a type that contains an ammonia gas generating agent such as urea that can generate ammonia gas when heated, or a type that contains ammonia gas generating agent such as trichloroacetic acid in the photosensitive layer. There are types that contain an alkali salt of an acid that loses its properties as an acid when heated, and types that use a higher fatty acid amide as a coloring aid and activate the diazo compound and coupling component by heating and melting.

In addition to maintenance problems such as the need for replenishing and discarding the developer as it uses a developer and the large size of the device, the wet type also has problems with maintenance, such as the fact that it is wet immediately after copying, making it difficult to make additions immediately. There are several problems such as copy images not being able to withstand long-term storage. In addition, like the wet type, the dry type requires replenishment of developer, requires gas absorption equipment to prevent the generated ammonia gas from leaking outside, and therefore requires larger equipment.
There are problems such as the smell of ammonia immediately after copying. On the other hand, unlike wet and dry types, heat-developable types have the advantage of maintenance because they do not require a developer, but all conventional types require high developing temperatures of 150°C to 200°C. Moreover, if the temperature is not controlled to about ±10° C., insufficient development may occur or the color tone may change, resulting in a problem of increased equipment cost. Furthermore, the diazo compound used for such high-temperature development is required to have high heat resistance, but such compounds are often disadvantageous in forming high concentrations. Many attempts have been made to develop at low temperatures (90° C. to +30° C.), but these have had the disadvantage of reducing the shelf life of the materials themselves.

As described above, although the thermal development type is expected to have sufficient advantages in terms of maintenance compared to the wet and dry types, the current situation is that it has not yet become the mainstream of diazo copying systems.

Now, in order to obtain the desired degree of color development by heating a material in which a layer containing a diazo compound, a coupling component, and a color development aid is provided on a support, each component must be melted and diffused instantly by heating. It is necessary to react to produce a colored pigment. If we design a material that can sufficiently develop color and obtain a high concentration even at low heating temperatures, there is always the possibility that this reaction will occur even while it is stored at room temperature before copying, resulting in white color. This appears as a phenomenon in which the bare skin becomes colored.

In order to solve this incompatible problem, the inventors of the present invention made extensive studies and found that a copying material is provided with a heat-developable photosensitive layer containing a diazo compound, a coupling component, and a coloring aid on a support. discovered that one basic solution is to contain the diazo compound in microcapsules.

However, even in copying materials using microcapsules containing diazonium salts, the photosensitive layer is opaque, making it difficult to use them as original drawings in copying drawings, which is one of the most frequently used copying materials.

Therefore, a first object of the present invention is to provide a copying material which is excellent in transparency and can obtain high color density even by low-temperature development.

A second object of the present invention is to provide a copying material which is excellent in transparency and has a good shelf life, that is, has a low density of background coloration (fog) during storage before copying.

A third object of the present invention is to provide a copying material which has excellent long-term storage stability of copied images (lower decrease in color J degree and lower increase in background density when stored in bright and dark places).

A fourth object of the present invention is to provide a copying material with excellent water resistance, chemical resistance, and abrasion resistance.

A fifth object of the present invention is to provide a copying material that has a simplified layer structure and is easy to manufacture.

A sixth object of the present invention is to provide a simple and easy-to-maintain image forming method that uses the copying material described above and combines a latent image forming process by exposure and a developing process by heating.

Means for Solving the Problems> The above aspects of the present invention are such that a heat-developable photosensitive layer containing a diazo compound, a coupling component, and a coloring aid is provided on a transparent polymer support. A heat-developable copying material characterized in that the diazo compound is contained in microcapsules, and the coupling component is dissolved in an organic solvent that is sparingly soluble or insoluble in water to exist as minute oil droplets. Achieved by copying materials.

The microcapsules used in the present invention have a
After emulsifying and dispersing a solution of a diazonium salt and the same or different compounds that react with each other to produce a polymeric substance in a non-aqueous solvent with a boiling point of 95°C in a hydrophilic protective colloid solution, the reaction vessel is reduced in pressure. The system is heated while moving the wall-forming substance to the surface of the oil droplet, and a polymer production reaction by polyaddition and polycondensation proceeds on the surface of the oil droplet to form a wall film. Preferably, the microcapsules are solvent-free.

The nonaqueous solvent for dissolving the diazonium salt used in the present invention is preferably at least one compound selected from halogenated hydrocarbons, fatty acid esters, ketones, and ethers, and forms the walls of microcapsules. It is preferable that the polymeric substance is formed from at least one selected from polyurethane and polyurea.

The non-aqueous solvent having a boiling point of 40° C. or more and 95° C. or less at normal pressure used in the present invention is preferably used in an amount of 5 to 100 parts by weight per 10 parts by weight of the diazonium salt as the solute.

Specific examples of the nonaqueous solvent used in the present invention are listed below, but the present invention is not limited thereto. (
) indicates the boiling point at normal pressure.

7 setone (58), iso7 methyl methyl ether (91)
, isopropyl methyl ketone (94) methyl isobutyrate (
92), ethyl isobutyl ether (79), ethyl isopropyl ether (54), ethyl propyl ether (64).

t-7mil chloride (86), ethylene chloride (84), isobutyl chloride (69), butyl chloride (7B).

Ethylidene chloride (57), propyl chloride (46), methylene chloride (42), ethyl formate (54).

Propyl formate (81), methyl methyl ether (
59), methyl chloroformate (71).

Ethyl acetate (7?), methyl acetate (57).

Carbon tetrachloride (77), 1,1-dichloropropane (86
), trichlorethylene (87).

Methyl propionate (80), propyl ether (91)
), methylchloroform (74).

Chloroform (61) The microcapsules of the present invention are characterized in that they do not substantially contain a non-aqueous solvent. We have developed a method for quantifying the amount of carbon dioxide, and defined the term "substantially free" in the present invention.

The microcapsules of the present invention are rarely used as capsule liquids, and are generally used in such a way that a coating liquid is prepared together with a coupler and a base, and the coating liquid is coated and dried to be present in a film of a copying material. Therefore, the amount of non-aqueous solvent contained in the coating film, which was present at several percent in the capsule liquid stage, was below the detection limit.

Microcapsule liquid produced by the production method of the present invention 0.
19 was weighed into a 20 cc volumetric flask, methanol was added to make the volume exactly 20 cc, and the volume was left for 30 minutes.

2 CC of the above methanol solution was measured using a microsyringe and injected into a gas chromatograph mass spectrometer (Hitachi M-80B). Column is TENAX 3mmφ
X1m was used. Quantification was performed using the m/z peak corresponding to the solvent to be measured. (For example, in the case of ethyl acetate, m/
z=43. For methylene chloride, peak 84 was used. ) According to this measuring method, the microcapsule liquid of the present invention contained 0.01 to 3.00% nonaqueous solvent.

When the preferred polymeric material is polyurea or polyurethane, the same or different compounds that form the walls of the microcapsules used in the present invention and which react with each other to produce a polymeric substance are incyanates shown below as corresponding monomers. X is selected from the compounds. The amount of monomer used is such that the average particle size of the microcapsules is 0.3μ to 12μ,
The wall thickness is determined to be 0.01μ to 0.3μ.

Specific examples of monomers used in the present invention are listed below, but the present invention is not limited thereto.

General formula [1] (n is an integer of 0 to 10) The aromatic incyanate used in the present invention is represented by the general formula (1), where n=Q, L 2+3I...
10 herbs or a mixture thereof.

Specific examples of the aliphatic polyhydric incyanate used in the present invention include hexamethylene diincyanate,
Propylene-1,2-diisocyanate, butylene-1
, 2-diisocyanate, ethyridine diisocyanate, cyclohexylene 1,4-diisocyanate, isophorone diisocyanate, adduct of hexamethylene diisocyanate and trimethylolpropane, adduct of hexamethylene diisocyanate and hexanetriol, hexamethylene diisocyanate biuret, hexamethylene These include isocyanurate forms of diisocyanate and isocyanurate forms of isophorone diisocyanate.

For the purpose of changing the physical properties of the wall of the microcapsules, diamines and diols may be present together with the incyanate to carry out the polymerization reaction.

The diazo compound and the coupling component contained in the photosensitive layer of the present invention develop color when they come into contact with each other when heated, and the diazo compound decomposes when exposed to light of a specific wavelength before the coloring reaction. Photodegradable compounds are used.

The photodegradable diazo compound as used in the present invention mainly refers to aromatic diazo compounds, and more specifically refers to aromatic diazonium salts, diazosulfonate compounds, and diazo-7mino compounds. It is generally said that the photodecomposition wavelength of a diazo compound is its maximum absorption wavelength. Also, the maximum absorption wavelength of diazo compounds ranges from around 200 nm to 70 nm, depending on their chemical structure.
It is known that it changes to about 0 nm. (“Photodecomposition and chemical structure of photosensitive diazonium salts” by Takahiro Tsunoda and Ao Yamaoka, Journal of the Photographic Society of Japan 29 (4) pp. 197-205 (
(1985)) That is, when a diazo compound is used as a photodegradable compound, it is decomposed by light of a specific wavelength depending on its chemical structure. Furthermore, by changing the chemical structure of the diazo compound, the hue of the dye after the reaction can be changed even when the same coupling component is used for the coupling reaction.

A diazo compound is a compound represented by the general formula ArN2X. (In the formula, Ar represents a substituted or unsubstituted aromatic ring%
N represents a diazonium group, and x represents an acid anion.

) In the present invention, a multicolor heat-developable copying material can be obtained by using diazo compounds having different photodecomposition wavelengths or different photodecomposition rates.

Specific examples of the diazo compound used in the present invention include the following examples.

4-Diazo-1-dimethylaminobenzene 4-Diazo-
2-Butoxy-5-chloro-1-dimethylaminobenzene 4-diazo-1-methylbenzylaminobenzene 4-diazo-1-ethylhydroxyethylaminebenzene 4-diazo-1-diethylamino-3-methoxybenzene 4-diazo-1 -Morpholinobenzene 4-Diazo-1-morpholino-2,5-dibutoxybenzene 4-Diazo-1-tolylmercapto-2,5-jethoxybenzene 4-Diazo-1-piperazino-2-methoxy-5-chlorobenzene 4-Diazo-1(SUN-dioctylaminocarbonyl)benzene 4-Diazo-1-(4-tart-octylphenoxy)benzene 4-Diazo-1-(2-ethylhexanoylpiperidino)-2,5-di Butoxybenzene 4-diazo-1-(2
,5-di-tert-7-milphenoxyα-butanoylpiperidino)benzene4-diazo-1-(4-methoxy)phenylthio-2,
5-Jethoxybenzene 4-diazo-1-(4-methoxy)benz7 mido2,
5-Jethoxybenzene 4-Diazo-1-pyrrolidino-2-methoxybenzene Specific examples of the acid that forms a diazonium salt with the above diazo compound include the following examples.

C,l F211+l COOH (n is an integer from 1 to 9) CM F, +, So3 H (m is an integer from 1 to 9) Boron tetrafluoride, Tetraphenylboron Hexafluorophosphoric acid, Aromatic carboxylic acid Aromatic Sulfonic acid.

Metal halides (zinc chloride, cadmium chloride, tin chloride)
In addition, in the present invention, in order to obtain a substantially transparent photosensitive layer, the coupling component is dissolved in an organic solvent that is sparingly soluble or insoluble in water, and then this is dissolved in a water-soluble organic solvent containing a surfactant. It is mixed with an aqueous phase containing a polymer as a protective colloid and used in the form of an emulsified dispersion.

The organic solvent used in this case can be appropriately selected from among high boiling point oils. In addition to esters, preferred oils include those of the following general formulas (11) to (1).
v] and triallylmethane (e.g.
Examples include tritolylmethane, tolyldiphenylmethane), terphenyl compounds (eg, terphenyl), and diphenyl ethers (diphenyl ether, propyldiphenyl ether). In the present invention, it is preferable to use esters among these from the viewpoint of emulsion stability.

[General Formula 11] In the formula, R1 and R2 may be the same or different, and each represents at least one substituent selected from hydrogen and a furkyl group having 1 to 18 carbon atoms.

(General formula II) In the R4 formula, R3,
R4 may be the same or different, and each represents at least one hydrogen group and a furkyl group having 1 to 12 carbon atoms.
Represents a substituent of a species.

n represents 1 or 2.

(General Formula IV) R5R6 In the formula, R5 and R6 may be the same or different, and each represents hydrogen and at least one substituent group derived from an alkyl group having 1 to 18 carbon atoms.

m represents an integer from 1 to 13.

Examples of the compound represented by the general formula j1 include dimethylnaphthalene, diethylnaphthalene, diisopropylnaphthalene, and the like.

Examples of the compound represented by general formula 111 include dimethylbiphenyl, diethylbiphenyl, diisopropylbiphenyl, diisobutylbiphenyl, and the like.

Examples of compounds represented by the general formula 1v include 1-methyl-
1-(2,4-dimethylphenyl)-1-phenylmethane, 1-ethyl-1-(2,4-dimethylphenyl)-
Examples include 1-phenylmethane, 1-propyl-1-(2,4-dimethylphenyl)-1-phenylmethane, and the like.

Examples of esters include phosphate esters (for example, triphenyl phosphate, tricresyl phosphate, butyl phosphate, octyl phosphate, diphenyl cresyl phosphate), phthalate esters (
For example, dibutyl phthalate, 2-ethylhexyl phthalate, ethyl octyl phthalate, butyl benzyl phthalate), dioctyl tetrahydrophthalate, benzoic acid esters (for example, ethyl benzoate, propyl benzoate, butyl benzoate, isopentyl benzoate). , benzyl benzoate), abietate esters (e.g. ethyl abietate, benzyl benzoate, etc.) 7 dioctyl dipate, isodecyl succinate 7 dioctyl gelate,
Oxalate esters (e.g. dibutyl oxalate, dipentyl oxalate), diethyl malonate, maleate esters (dimethyl maleate, diethyl maleate, dibutyl maleate), tributyl citrate, sorbate esters (e.g. methyl sorbate, ethyl sorbate,
butyl sorbate), sebacate esters (e.g. dibutyl sebacate, dioctyl sebacate), ethylene glycol esters (monoesters and diesters of formic acid, butyric acid, lauric acid, valmitic acid, stearic acid, etc.), triacetin, diethyl carbonate, diphenyl carbonate,
Examples include boric acid esters (eg, tributyl borate). These oils may be used alone or in combination with other oils.

In the present invention, a low boiling point auxiliary solvent can also be added to the above organic solvent. Particularly preferred examples of such co-solvents include ethyl acetate, isopropyl acetate, butyl acetate and methylene chloride.

The water-soluble polymer to be contained as a protective coconvex in the aqueous phase to be mixed with the oil phase containing these components should be appropriately selected from among known 7-ionic polymers, nonionic polymers, and amphoteric polymers. However, polyvinyl alcohol, gelatin, cellulose derivatives, etc. are preferable.

Furthermore, as the surfactant to be contained in the aqueous phase, it is possible to use any 7-ionic or non-ionic surfactant that does not interact with the protective colloid and cause precipitation or aggregation. Preferred surfactants include sodium flukylbenzenesulfonate, sodium flukylsulfate, dioctyl sodium sulfosuccinate, polyfulkylene glycol, and the like.

The emulsified dispersion in the present invention is prepared by mixing and dispersing an oil phase containing the above components and an aqueous phase containing a protective colloid and a surfactant using a means commonly used for fine particle emulsification, such as high-speed stirring and ultrasonic dispersion. It can be easily obtained.

The oil droplet size (diameter) of this emulsified dispersion is Haze or 40
% or less, the thickness is preferably 7 μm or less. More preferably, it is within the range of 031 to 5μ.

Moreover, the value of the ratio of the oil phase to the aqueous phase (oil phase weight/aqueous phase weight) is preferably 0.02 to 0.6. Furthermore, it is preferably 0.1 to 0.4. If it is less than 0.02 μm, the aqueous phase will be too large and diluted, making it impossible to obtain sufficient color development, while if it is more than 0.6 μm, the viscosity of the liquid will increase, resulting in inconvenience in handling and a decrease in stability of the coating liquid.

Coupling components used in the invention form dyes by coupling with diazo compounds in a basic atmosphere, and include so-called active methylene compounds having a methylene group next to a carbonyl group, phenol derivatives, and naphthol derivatives. , Specific examples include the following.

Resorcin, phloroglucin, 2I Sodium 3-dihydroxynaphthalene-6-sulfonate, 1-hydroxy-2-naphthoic acid morpholinopropylamide, 1,5
-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,3-dihydroxy-6-sulfanylnaphthalene, 2-hydroxy-3-naphthoic acid morpholinopropylamide, 2-hydroxy-3-naphthoic acid octylamide, 2-hydroxy-3 - naphthoic acid 7nylide,
Pencylacetonilide, 1-phenyl-3-methyl-
5-pyrazolone, l-(2,4,6-drichlorophenyl)-3-7nilino-5-pyrazolone, 2-[3-α-
(2,5-di-tert-amylphenoxy)-butanamidehenz7mido]phenol, 2I 4-bis-(
benzoylacetamino)toluene, 1,3-bis-(
pivaloyl7cetaminomethyl)benzene These coupling components can be used individually or in combination of two or more, and any hue can be obtained as required.

As one of the color development aids of the present invention, it is preferable to add a basic substance as necessary for the purpose of making the system basic during thermal development and promoting the coupling reaction.

As these basic substances, used are sparingly water-soluble or water-insoluble basic substances, and substances that generate alkali upon heating.

Basic substances include inorganic and organic ammonium salts,
Organic amines, 7mide, urea and thiourea and their derivatives,
Nitrogen-containing compounds such as thiazoles, virols, pyrimidines, piperazines, guanidines, indoles, imidazoles, imidacillines, triazoles, morpholines, piperidines, 7-midine necks, formamidines, and pyridines are listed. It will be done. Two or more of these basic substances can be used in combination.

In order to obtain a copying material with excellent transparency, which is the object of the present invention, the above basic substance is dissolved in an organic solvent that is sparingly soluble or insoluble in water together with a coupling component, and is in the form of a dispersion that is emulsified and dispersed. It is preferable to use

In the present invention, the diazo compound is 0.05 to 5.09
/m2 coating is preferred. In addition, diazo compound 1
It is preferable to use the coupling component in an amount of 0.1 to 30 parts by weight and the basic substance in an amount of 0.1 to 30 parts by weight.

In addition, the color development aid of the present invention contains phenol derivatives, naphthol derivatives, alkoxy-substituted benzenes, alkoxy-substituted naphthalenes, hydroxy compounds, amide compounds, sulfonamide compounds can be added. These compounds are thought to lower the melting point of the coupling component or the basic substance, or to improve the thermal permeability of the microcapsule wall, resulting in a high color density.

The color development aid of the present invention also does not include heat-fusible substances.

The heat-melting substance is a substance that is solid at room temperature and has a melting point of 50°C to 150°C and melts by heating, and is a substance that dissolves a diazo compound, a coupling component, or a basic substance. Specific examples of these compounds include fatty acid 7mide, N-substituted fatty acid 7mide, ketone compounds, urea compounds, esters, and the like.

The copying material of the invention can be coated using a suitable binder.

Binders include polyvinyl alcohol, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose, gum arabic, gelatin, polyvinylpyrrolidone, casein, styrene-butadiene latex, acrylonitrile-butadiene latex, polyvinyl acetate, polyacrylic acid ester, ethylene-vinyl acetate, etc. Various emulsions such as polymers can be used. The amount used is 0.59 to 59/m2 in terms of solid content.

In the present invention, in addition to the above-mentioned materials, citric acid, tartaric acid, oxalic acid, phosphoric acid, phosphoric acid, pyrophosphoric acid, etc. can be added as stabilizers.

In addition, the copying material of the present invention can be viewed from one side of the transparent support through a transmitted image or a reflected image. In particular, in the latter case, the photosensitive layer is coated so that the back side of the background part cannot be seen through. A white pigment may also be added.

In the present invention, "substantially transparent" means a haze of 40% or less (measured with an integrating sphere HTR meter manufactured by Nippon Seimitsu Kogyo Co., Ltd., expressed as n≦), preferably 30"3≦. However, , the transparency of an actual copying material sample is greatly influenced by light scattering based on minute irregularities on the surface of the copying material.Therefore, the inherent transparency of the copying material, that is, the transparency inside the photosensitive layer, is a problem in the present invention. When measuring the properties using a haze meter, a simple method is to attach a transparent adhesive tape onto the photosensitive layer, and then evaluate the measured value by substantially excluding surface scattering.

The copying material of the present invention may also be provided with a protective layer on top of the photosensitive layer in order to increase the mechanical strength of the surface. As a protective layer, one consisting of silicon-modified polyvinyl alcohol and colloidal silicone is suitable for the purpose of the invention.

The transparent polymer support used in the present invention is a polyester film such as polyethylene terephthalate or polybutylene terephthalate, a cellulose derivative film such as cellulose triacetate film, a polystyrene film,
There are films made of polyolefins such as polyethylene, etc.
These can be used as a plant or by pasting them together.

The thickness of the transparent support used is 20 to 200 μm, particularly preferably 50 to 100 μm.

<Effects of the Invention> The copying material of the present invention has excellent transparency and can obtain high color density even by low-temperature thermal development, so it can be suitably used for second original drawings, which are frequently used in the field of drawing copying. I can do it. In particular, the wet type that is currently widely used,
Compared to dry-type diazo copying materials, it has advantages in terms of maintenance and provides back-quality original drawings.

The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited thereby.

<Example> 3.45 parts of 1-morpholino-2,5-dibutoxybenzene-4-diazonium hexafluorophosphate, xylylene diinocyanate and trimethylolpropane (3.45 parts)
:1) 18 parts of the adduct were added to 10 parts of ethyl acetate and dissolved by heating. This diazo compound solution was mixed with an aqueous solution containing 5.2 parts of polyvinyl alcohol dissolved in 58 parts of water, and emulsified and dispersed at 20°C to obtain an emulsion having an average particle size of 2.5 μm. 100 parts of water was added to the obtained emulsion and heated to 60° C. while stirring, and after 2 hours, a capsule liquid containing a diazo compound in the core material was obtained. During this reaction, the vessel was maintained under reduced pressure of OOmmHq to 130mmHg using a water jet pump.

The ethyl acetate in the capsule liquid was determined by the measurement method described above.
A value of 0.87 inches was obtained.

Fukini 1- (2,4,6-drichlorophenyl)-3-
[3-(α-(2,5-dimethylphenoxy)acetamido)bensamide]-2-pyrazoline-5-
25 parts of tricresyl phosphate and 50 parts of triphenylguanidine were dissolved in a pre-mixed solution of 1aO part of tricresyl phosphate and 200 parts of ethyl acetate. This solution was added to 1700 parts of a 4% by weight aqueous solution of polyvinyl alcohol, mixed, and emulsified at 20°C to obtain an emulsified dispersion having an average particle size of 3 μm.

To 50 parts of the capsule solution of the diazo compound obtained as described above, 50 parts of a dispersion of a coupling component and triphenylguanidine and 10 parts of a 40% calcium carbonate dispersion were added to prepare a coating liquid. This coating solution was coated onto a 75 μm polyethylene terephthalate transparent film using a coating bar so that the dry weight was 15 c+/m 2 and dried at 50° C. for 1 minute to prepare copying material A.

Copying material B was prepared in the same manner as copying material A except that a capsule liquid prepared by the following method was used instead of the above capsule liquid.

Preparation of capsule liquid for copying material B = 1-morpholino-2
, 3.45 parts of 5-dibutoxybenzene-4-diazonium hexafluorophosphate and 18 parts of an adduct of xylylene diisocyanate and trimethylolpropane (3:1) in a mixed solvent of 6 parts of tricresyl phosphate and 5 parts of ethyl acetate. and heated to dissolve. This solution of diazo compound is
It was mixed with an aqueous solution of 5.2 parts of polyvinyl alcohol dissolved in 58 parts of water, emulsified and dispersed at 20°C, and the average particle size was 2.
．． A 5μ emulsion was obtained. 100 parts of water was added to the obtained emulsion and heated to 60° C. while stirring, and after 2 hours, a capsule liquid containing a diazo compound in the core substance was obtained.

In addition, copying material C was prepared in the same manner as in the copying material day except that a dispersion prepared by the following method was used instead of the dispersion of the coupling component and triphenylguanidine described above.

Preparation of dispersion for copying material C: 1-C2,4°6-drichlorophenyl')-3-[3-(α-(2,5-di-tert-amylphenoxy)7cetamido)henzamide]-2- 25 parts of pyrazoline-5-one and 50 parts of triphenylguanidine were added to 1700 parts of a 4% by weight aqueous solution of polyvinyl alcohol and dispersed for about 24 hours in a sand mill to obtain a dispersion with an average particle size of 3 μm.

The haze transmittance of this copying material Gi 4 was measured using an integral method HTR meter manufactured by Nippon Seimitsu Kogyo, and the transparency was also visually confirmed. The results are shown in Table 1.

C Table 1] □ 1 Haze transparency of 1 copy material: 1 type of transparency
% 1 ・1' □ (A' 10 □ Good □ Test original on copying materials A-C (a circle with a diameter of 3 cm painted uniformly black on tracing paper using a 28-lead screen)
was placed on top and exposed to fluorescent light. At this time, a fluorescent lamp whose emission spectrum has a maximum value at 420 nm was used. Next, an image was formed by heating for 3 seconds using a heat block heated to 120°C. Similarly, tests were also conducted at heat block temperatures of 100°C and 160°C. Also, to test shelf life, 40
After being stored at 90% RH for 24 hours, it was exposed and developed at 120'C in the same manner. A 24 hour storage test was also conducted at 600C and 30% RH.

The densities of the colored parts and background parts of the samples obtained in each test were measured using a Macbeth densitometer.

Table 2 shows the results of tests with different heating temperatures, and Table 3 shows the results of the pre-copy storage test.

As shown in Table 2, sample A has the highest image transmission density. Furthermore, this feature is also apparent in the forced deterioration test for evaluating shelf life, as shown in Table 3.

−　　　Table 2〕

Claims (1)

[Scope of Claims] 1) A copying material in which a heat-developable photosensitive layer containing a diazo compound, a coupling component, and a coloring aid is provided on a transparent polymer support, in which the diazo compound is contained in microcapsules. 1. A heat-developable copying material, characterized in that the coupling component is dissolved in an organic solvent that is sparingly soluble or insoluble in water to exist as minute oil droplets. 2) The microcapsules are prepared by dissolving a solution of a diazonium salt and the same or different compounds that react with each other to produce a polymer substance in a non-aqueous solvent with a boiling point of 40 to 95°C at normal pressure, and adding a hydrophilic protective colloid to the solution. After emulsification and dispersion in the solution, the temperature of the system is raised while reducing the pressure in the reaction vessel to move the wall-forming substance to the oil droplet surface, and to advance the polymer production reaction by polyaddition and polycondensation on the oil droplet surface to form a wall. The heat-developable copying material according to claim 1, which is produced by a method for obtaining microcapsules substantially free of solvent by forming a film. 3) The heat-developable copying material according to claim 2, wherein the polymeric substance is formed of at least one selected from polyurea and polyurethane. 4) The heat-developable copying material according to claim 1, wherein the organic solvent that is sparingly soluble or insoluble in water is an ester compound. 5) For the copying material according to claim 1,
A first step of forming a latent image on the photosensitive layer by exposing it to light corresponding to the image of the original, and fixing the area other than the image forming portion by light irradiation; and after the first step, the entire surface of the photosensitive layer of the copying material is covered. An image forming method comprising a second step of heating and developing with a heating means.