JPH0968773A - Thermal development type diazo copy material - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain a heat-developable diazo copying material having high color development and excellent raw storage stability. In a heat developable diazo copying material in which at least a diazo compound, a coupler, a basic substance and a eutectic agent are attached to a support, at least one component of the diazo compound, the coupler and the basic substance is encapsulated. At the same time, a copolymer containing a monomer having a carboxyl group as a constituent is used as a binder of at least one component.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-developable diazo copying material in which a latent image is formed by exposing a transparent or semi-transparent original in an overlapping manner and then developing the latent image with heat. The present invention also relates to a heat-sensitive recording material, particularly a heat-sensitive recording material capable of being optically fixed.

[0002]

2. Description of the Related Art Heat-developing diazo copying materials are generally paper,
A photosensitive layer containing a diazo compound, a coupling component and a color-forming aid as main components is provided on a support such as a film, and urea trichloroacetic acid sodium is used as the color-forming aid. This kind of diazo copying material is 180 ~
Development is performed by heating at 200 ° C., and the developing mechanism uses an alkali that is decomposed and generated by heating. Further, as an attempt of low temperature development, a heat-fusible substance such as a higher fatty acid amide is used as a color-developing aid, but the development mechanism uses activation of a diazo compound and a coupling component by heating and melting. .

[0003]

However, in the conventional case, pre-coupling gradually progressed during storage and undesired coloring was sometimes caused. Therefore, JP-A-57-
As disclosed in JP-A-42042, JP-A-57-45094, JP-A-57-125091, and the like, any one of a diazo compound, a coupling component, and a basic substance is used as a discontinuous particle. It has been proposed to prevent contact between components and prevent precoupling by making them exist in a form, but if the respective particle diameters are made small in order to obtain high thermal sensitivity and color density, the desired raw storage stability is obtained. There was a problem that was not obtained.

Further, as disclosed in Japanese Patent Publication No. 4-75147, an encapsulation technique in which only a diazo compound is contained as a core substance in a microcapsule and polyurethane or polyurea is used as a partition wall around the core substance in a polymerization reaction. However, as disclosed in JP-A-61-219688, there is a problem that desired storage stability cannot be obtained unless unencapsulated diazo is removed.

Further, there has been proposed an in-liquid drying method in which a partitioning agent as disclosed in Japanese Patent Application Laid-Open No. 57-44141 encapsulates a coupling component with a nonpolar wax. Therefore, the coupling reaction at the time of heat melting was suppressed, and there were many problems in practical use. As described above, it is difficult for the conventional heat-developing diazo copying material to achieve both high color development and raw storability, and the encapsulation of the diazo component is not excellent in manufacturing suitability.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a heat-developable diazo copying material which has a high color-developing property and is excellent in raw storability.

[0007]

According to the present invention, firstly, in a heat-developable diazo copying material in which at least a diazo compound, a coupler, a basic substance and a eutectic agent are attached to a support, the diazo compound is used. , A heat-developable diazo, characterized in that at least one component of a coupler and a basic substance is encapsulated in a capsule, and a copolymer having a monomer having a carboxyl group as a constituent component is used as a binder of at least one component. Copy materials are provided.

Secondly, in the heat-developable diazo copying material described in the above-mentioned first, there is provided a heat-developable diazo copying material characterized in that the copolymer is a styrene-acrylic acid copolymer. .

Thirdly, in the heat-developable diazo copying material described in the first item, the copolymer is a mixture of a styrene-acrylic acid copolymer and an isobutylene-maleic anhydride copolymer, and the mixture thereof. The ratio is 4: 1 to 1: 1 by weight.
There is provided a heat developable diazo copying material characterized by being in the range of 4.

Fourthly, in the heat-developable diazo copying material described in the above-mentioned first, a heat-development agent containing a eutectic agent having a melting point of 80 to 150 ° C. which is eutectic with the thermoplastic resin and the coupler. A type diazo copying material is provided.

Fifth, in the heat-developable diazo copying material described in the above first, a layer containing the diazo compound and a layer containing the coupler, the basic substance and the eutectic agent are laminated on a support. A heat-developable diazo copying material is provided.

The present invention will be described in detail below. As a result of various studies to achieve the above-mentioned object, the present inventors have encapsulated at least one component of a color-forming component, a diazo compound, a coupler, and a basic substance, in a microcapsule, and By using a copolymer having a monomer having a carboxyl group as a constituent component as at least one component of a binder, heat development which is excellent in suppressing background fogging after storage of raw photosensitive paper and also excellent in color developability The present invention has been completed by finding that a type diazo copying material can be obtained.

As described above, the heat-developable diazo copying material of the present invention contains at least one component selected from the diazo compound, the coupler, and the basic substance, which are color-forming components, in microcapsules and at least one of the color-forming components.
The greatest feature is that a copolymer containing a monomer having a carboxyl group as a constituent component is used as a binder for the component.

Background fogging that occurs when raw photo-sensitive paper is stored is caused by contact between color forming components. Therefore, by separating the color forming components by some method, the background fogging can be suppressed. Separation of the color-forming component is mostly achieved mainly by the method of encapsulating the color-forming component in microcapsules. However, the presence of uncapsulated color-forming component causes background fog during storage.

In order to solve these problems, the uncapsule is removed as described above, or the particle size of the color-forming component is increased, that is, the reactivity of the color-forming component particles is decreased to save the background texture after storage. Fogging is also suppressed, but the result is that the production suitability is not excellent, or conversely, the color developability is reduced.

Therefore, in order to obtain a desired storability without requiring a step of removing these unencapsulated components and without deteriorating the reactivity of the color-forming component particles, a thermoplastic resin having a high isolation property, that is, It has been found that the object can be achieved by using the above copolymer as a binder for these color forming components.

In order to achieve the above-mentioned object with a resin which has been conventionally used as a binder, a large amount of resin is required and, conversely, the color developability is deteriorated. However, a copolymer containing a monomer having a carboxyl group as a constituent component When the coalescence is used as a binder, even if used in a large amount, the color fog is not impaired and the background fog is suppressed.

This is because the copolymer can retain an alkali by forming a salt with an alkaline substance, and
This is because the styrene-acrylic acid copolymer resin has a good isolation property. Furthermore, when the styrene-acrylic acid copolymer and the isobutylene-maleic anhydride copolymer are mixed and used, isobutylene-maleic anhydride having high acid strength is dissociated from the styrene-acrylic acid copolymer during storage. Since it can retain alkali, it further suppresses background fog.

However, if the ratio of the isobutylene-maleic anhydride copolymer is too high, on the contrary, the necessary alkali will be retained during color development, so that the isobutylene-maleic anhydride copolymer will be contained in the copolymer mixture. The weight ratio is in the range of 0.2 to 0.8, that is, the mixing ratio of the styrene-acrylic acid copolymer and the isobutylene-maleic anhydride copolymer is 4: 1 to 1: 4. Preferably.

The melting point of the eutectic agent which is eutectic with the copolymer and the coupler is 8 so that dry fog does not occur during coating and drying, and development can be carried out at 110 to 150 ° C.
It is preferably in the range of 0 to 150 ° C.

The main components used in the present invention are listed below. The diazo compound used in the present invention is a diazonium salt represented by the general formula ArN2 + X- (wherein A is
r represents a substituted or unsubstituted aromatic moiety, ArN
2+ represents a diazonium salt, and X- represents an acid anion).

Specific examples include 4-diazo-N, N-dimethylaniline, 4-diazophenylmorpholine and 4-diazophenylmorpholine.
Diazo-N, N-dibutylaniline, 4-diazo-2,
5-dimethoxyphenylmorpholine, 4-diazo-2,
5-diethoxyphenyl mophorin, 4-diazo-2,5
-Dipropoxyphenylmorpholine, 4-diazo-2,
5-dibutoxyphenylmorpholine, 4-diazo-2,
5-dibutoxy-N-benzyl-N-ethylaniline,
4-diazo-2,5-dibutoxy-N, N-dibutylaniline, 4-diazo-2,5-dibutoxy-N-benzyl-N-ethoxyaniline, 4-diazo-2,5-dibutoxyphenylpiperazine, 4 -Diazo-2,5-diethoxyphenylpyrrolidine, 4-diazo-2,5-dipropoxyphenylpiperazine, 4-diazo-2,5-diethoxy-N, N-dimethylaniline, 4-diazo-1
-Benzoylamino-2,5-dibutoxybenzene, 4
-Diazo-1- (4'-methoxybenzoylamino)-
2,5-dimethoxybenzene, 4-diazo-1- (4 '
-Methoxybenzoylamino) -2,5-diethoxybenzene, 4-diazo-1- (4'-methoxybenzoylamino) -2,5-dipropoxybenzene, 4-diazo-1- (3'-chlorobenzoylamino) ) -2,5-Diethoxybenzene, 4-diazo-1- (3'-methoxybenzoylamino) -2,5-dibutoxybenzene, 4
-Diazo-1- (3'-methoxybenzoylamino)-
2,5-Dimethoxybenzene, 4-diazo-1-phenylmercapto-2,5-dipropoxybenzene, 4-diazo-1- (4′-toluylmercapto) -2,5-diethoxybenzene, 4-diazo- 1- (4'-methoxyphenylmercapto) -2,5-dibutoxybenzene,
4-diazo-1- (4'-chlorophenylmercapto)
-2,5-dimethoxybenzene, 4-diazo-1-
(3′-toluylmercapto) -2,5-diethoxybenzene, 4-diazo-1- (3′-methoxyphenylmercapto) -2,5-dipropoxybenzene, 4-diazo-1- (2′-toluyl) Mercapto) -2,5-dibutoxybenzene, 4-diazo-1-phenoxy-2,5
A double salt of a chloride such as dibutoxybenzene and 4-diazo-1- (4′-methoxyphenoxy) -2,5-diethoxybenzene and a metal chloride such as zinc chloride, cadmium chloride and tin chloride, and the above Examples thereof include salts of inorganic acids such as sulfuric acid, hexafluorophosphoric acid, and tetrafluoroboric acid of diazo compounds.

As the coupling component, all those used in general two-component type diazo copying materials can be used, but a naphthol AS type coupler which is relatively eutectic at 80 ° C. to 150 ° C. together with a eutectic agent can be used. Desirably, more specifically, Naphthol AS, Naphthol AS-D,
Naphthol AS-BO, Naphthol AS-BS, Naphthol AS-E, Naphthol AS-G, Naphthol AS-
LB, naphthol AS-OL, naphthol AS-SW,
Naphthol AS-TR and the like.

Examples of the basic substance or the substance which exhibits basicity upon heating and melting include sodium hydroxide, potassium carbonate, sodium hydrogen carbonate, sodium acetate, ammonium acetate, ammonium chloride, ammonium sulfate, ammonium citrate, stearylamine, urea and thio. Urea, allylurea, allylthiourea, methylthiourea, ethylenethiourea, sodium trichloroacetate, guanidine trichloroacetate, morphonium trichloroacetate, guanidine carbonate, guanidine sulfate, aminoguanidine sulfate, 1,
2,3-triphenylguanidine, 1,2-ditolylguanidine, 1,2-dicyclohexylguanidine, imidazole, benzimidazole, 2-heptadecylimidazole, 2-benzylimidazole, 4-phenylimidazole, 2-phenyl-4 -Methylimidazole,
2-undecyl imidazoline, 1,2-diphenyl-
4,4-dimethyl-2-imidazoline, N, N′-dibenzylpiperazine, 4,4′-dithiomorpholine, 2-
There are aminobenzothiazole and the like, but among them, those which are sparingly water-soluble or water-insoluble are more preferable. These color-forming aids can be used in combination of two or more kinds.

Examples of the eutectic agent include higher fatty acid amides having 10 to 20 carbon atoms and N-substituted higher fatty acid amides,
Specifically, lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, arachidic acid amide, behenic acid amide, eicoic acid amide, elaidic acid amide, N-methylol stearic acid amide, N-methylol caproic acid amide, N-methylol lauric acid amide,
N-methylol behenic acid amide and the like.

In the heat-developable diazo copying material of the present invention, in addition to the color-forming component, various additives that are applied to ordinary diazo-based heat-sensitive recording materials, and sodium naphthalene monosulfonate and sodium naphthalene disulfonate as storage stability improvers. , Sodium naphthalene trisulfonate, sulfosalicylic acid, cadmium sulfate, magnesium sulfate, cadmium chloride, zinc chloride and the like can be used. Further, thiourea, urea or the like can be used as an antioxidant, caffeine, theophylline acid or the like can be used as a solubilizer, and a small amount of saponin can be added.

When it is used as a light-fixing type heat-sensitive recording material, a filler can be added for the purpose of preventing sticking to the thermal head and improving running property. For example, organic and inorganic solid particles such as styrene resin fine particles, urea-formalin condensate resin fine particles, aluminum hydroxide, magnesium hydroxide, calcium carbonate, titanium, talc, kaolin, silica and alumina. Metal soaps can also be used for the same purpose.

As binders for the above materials, polyvinyl alcohol, polyacrylamide, casein, gelatin, starch and derivatives thereof, in addition to the above copolymers,
Polyvinylpyrrolidone, carboxymethylcellulose,
Water-soluble resins such as methyl cellulose, ethyl cellulose and hydroxyethyl cellulose, and various emulsion resins such as polyvinyl acetate, polyacrylic acid ester, vinyl chloride-acrylic acid ester copolymer and ethylene-vinyl acetate copolymer can be used.

When diazo, which is sparingly soluble in water, is applied by dissolving it in an organic solvent, a resin soluble in an organic solvent may be used as a binder. For example, vinyl chloride type, vinyl acetate type, chloride type, etc. Vinyl-vinyl acetate copolymer, vinyl acetate-vinylidene chloride copolymer, polystyrene,
Butyral type, polycarbonate type, acrylic acid derivative type resin, modified PVA, gum arabic, diisobutene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, ethylene-acrylic acid copolymer, styrene-methacrylic acid copolymer A combination or the like can be used in combination with the above copolymer, and these resins can be used in combination of two or more kinds.

For the production of the microcapsules which can be used in the present invention, any method such as an interfacial polymerization method, an internal polymerization method, an external polymerization method and a submerged drying method can be adopted. It is preferable to employ the interfacial polymerization method and the in-liquid drying method.

The heat-developable diazo copying material of the present invention can be advantageously applied to various other fields of heat-sensitive recording, especially as a recording sheet for facsimiles and electronic computers which require high-speed recording. In this case, the characters and images recorded on the surface of the recording paper can be fixed by forming an image by heating and then decomposing the unreacted diazo compound by exposure.

Further, the recording material of the present invention can be applied to the recording and preparation of necessary items for securities, gift certificates, entrance tickets, certificates, slips, etc. by utilizing its fixing property.

[0033]

EXAMPLES Examples are shown below, but the present invention is not limited to these examples. In addition, "part" indicating the addition amount represents "part by weight".

<Microencapsulation of Coloring Component> (Diazo Component) 4-diazo-1-morpholino-2,5-dibutoxybenzene hexafluorophosphate 2.0 parts xylylene diisocyanate and trimethylolpropane (3: 1) Addition product 10.0 parts Dibutyl phthalate 20.0 parts Ethyl acetate 5.0 parts A diazo solution (A) was prepared with the above composition. Diazo solution (A) 37.0 parts PVA 5.2 parts Water 58.0 parts The above liquid was emulsified and dispersed at 20 ° C to obtain an emulsion having an average particle diameter of 3 µm. Add 100 parts of water to this emulsion and stir 40
The mixture was heated to ˜70 ° C., and after 2 hours, a diazo capsule liquid (1) containing a diazo compound was obtained.

(Coupler component) Ethyl cellulose 5.0 parts Ethyl acetate 20.0 parts Naphthol AS 20.0 parts A coupler dispersion (B) was prepared with the above composition. Coupler dispersion (B) 45.0 parts PVA 5.0 parts Water 120.0 parts The above liquid was emulsified and dispersed at 20 ° C. to obtain an emulsion having an average particle diameter of 3 μm. The solvent was evaporated while stirring this emulsion to obtain a coupler capsule liquid (2) having a coupler solid content of 20%.

(Basic substance) A basic substance capsule liquid (3) was obtained in the same manner as the encapsulation of the coupler component except that naphthol AS of the coupler component was replaced with triphenylguanidine. When the color-forming component is used without being encapsulated, the average particle diameter of the coupler and the dispersion of the basic substance are 3 μm and the solid content weight ratio is 2 μm, respectively.
A 0% solution, Naphthol AS dispersion (2) and triphenylguanidine dispersion (2) were used. In this example, the precoat layer containing the coupler and the basic substance was applied on the support, and then the photosensitive layer containing the diazo component was laminated. However, the color forming component was applied in one layer and applied. Is also good.

[Example 1] (Precoat liquid (1)) Naphthol AS dispersion liquid (2) 15.0 parts Triphenylguanidine dispersion liquid (2) 15.0 parts Styrene-acrylic acid copolymer ammonium salt (20%) ) 30.0 parts Behenamide dispersion (20%) 25.0 parts Silica 2.0 parts Polyvinyl alcohol (10%) 10.0 parts Water 3.0 parts

(Photosensitive liquid (1)) Diazo capsule liquid (1) 75.0 parts Tartaric acid 0.2 parts Isopropanol 0.5 parts Polyvinyl alcohol 5.0 parts Silica 1.0 parts Water 18.3 parts Pre-coat liquid ( 1) is coated and dried on a high-quality paper using a wire bar, and the photosensitive liquid (1) is coated and dried so that the solid content deposition amount becomes 5.0 g / m2 and then the diazo component deposition amount becomes 0.8 g / m2. did.

[Example 2] (Precoat liquid (2)) Coupler capsule liquid (2) 15.0 parts Triphenylguanidine dispersion liquid (2) 15.0 parts Styrene-acrylic acid copolymer ammonium salt (20%) 30.0 parts Behenamide dispersion (20%) 25.0 parts Silica 2.0 parts Polyvinyl alcohol (10%) 10.0 parts Water 3.0 parts

(Photosensitive Solution (2)) 4-Diazo-2,5-dibutoxyphenylmorpholine chloride / 1/2 zinc chloride 1.5 parts Tartaric acid 0.5 part Isopropanol 1.0 part Polyvinyl alcohol 10.0 Part Silica 2.0 parts Water 85.0 parts The above precoat liquid (2) was applied and dried on woodfree paper using a wire bar to give a solid content of 5.0 g / m @ 2, and then a diazo component adhesion of 0. The photosensitive solution (2) was applied and dried so that the amount was 8 g / m 2.

[Example 3] (Precoat liquid (3)) Naphthol AS dispersion liquid (2) 15.0 parts Basic substance capsule liquid (3) 15.0 parts Styrene-acrylic acid copolymer ammonium salt (20%) ) 30.0 parts Behenamide dispersion (20%) 25.0 parts Silica 2.0 parts Polyvinyl alcohol (10%) 10.0 parts Water 3.0 parts

(Photosensitive Solution (2)) 4-Diazo-2,5-dibutoxyphenylmorpholine chloride / 1/2 zinc chloride 1.5 parts Tartaric acid 0.5 part Isopropanol 1.0 part Polyvinyl alcohol 10.0 Part Silica 2.0 parts Water 85.0 parts The above precoat liquid (3) was applied to high-quality paper using a wire bar and dried to give a solid content of 5.0 g / m 2, and then a diazo component adhesion of 0. The photosensitive solution (2) was applied and dried so that the amount was 8 g / m 2.

[Example 4] (Precoat liquid (4)) Coupler capsule liquid (1) 15.0 parts Triphenylguanidine dispersion liquid (2) 15.0 parts Styrene-acrylic acid copolymer ammonium salt (20%) 15.0 parts Isobutylene-maleic anhydride copolymer Ammonium salt (20%) 15.0 parts Behenamide dispersion (20%) 25.0 parts Silica 2.0 parts Polyvinyl alcohol (10%) 10. 0 parts water 3.0 parts

(Photosensitive solution (2)) 4-diazo-2,5-dibutoxyphenylmorpholine chloride / 1/2 zinc chloride 1.5 parts tartaric acid 0.5 part isopropanol 1.0 part polyvinyl alcohol 10.0 parts Silica 2.0 parts Water 85.0 parts The above precoat liquid (4) is applied and dried on a fine paper using a wire bar to give a solid content of 5.0 g / m2, and then a diazo component of 0.8 g. The photosensitive solution (2) was applied and dried so as to be / m 2.

Comparative Example 1 In Example 1, styrene-
The conditions were the same as in Example 1 except that polyvinyl alcohol was used instead of the ammonium salt of acrylic acid copolymer.

[Comparative Example 2] In Example 2, styrene-
The same conditions as in Example 2 were applied except that polyvinyl alcohol was used instead of the acrylic acid copolymer ammonium salt.

[Comparative Example 3] In Example 3, styrene-
The same conditions as in Example 3 were used except that polyvinyl alcohol was used instead of the acrylic acid copolymer ammonium salt.

[Comparative Example 4] (Precoat liquid (5)) Coupler capsule liquid (1) 15.0 parts Triphenylguanidine dispersion liquid (2) 15.0 parts Styrene-acrylic acid copolymer ammonium salt (20%) 3.0 parts Isobutylene-maleic anhydride copolymer ammonium salt (20%) 27.0 parts Behenamide dispersion (20%) 25.0 parts Silica 2.0 parts Polyvinyl alcohol (10%) 10. 0 parts water 3.0 parts

(Photosensitive solution (2)) 4-diazo-2,5-dibutoxyphenylmorpholine chloride / 1/2 zinc chloride 1.5 parts Tartaric acid 0.5 part Isopropanol 1.0 part Polyvinyl alcohol 10.0 Part Silica 2.0 parts Water 85.0 parts The above pre-coat liquid (5) was applied and dried on woodfree paper using a wire bar to give a solid content of 5.0 g / m 2, and then a diazo adhesion of 0.8 g. The photosensitive solution (2) was applied and dried so as to be / m 2.

Comparative Example 5 The same conditions as in Example 2 were used except that the ethylene biscapric acid amide dispersion liquid was used in place of the behenic acid amide dispersion liquid in Example 2.

[Comparative Example 6] The same procedure as in Example 2 was repeated except that the ricinoleic acid amide dispersion liquid was used in place of the behenic acid amide dispersion liquid in Example 2. Therefore, the photosensitive paper was not evaluated.

The heat-developable diazo copying materials of Examples and Comparative Examples obtained as described above were used as COPI ART10.
The photosensitivity was measured with a copy scale 4 of 0 (manufactured by Fuji Photograph Co., Ltd., development temperature: about 120 ° C.). Further, the unexposed / completely exposed sample was developed on the copy scale 4, and the color-developed portion (unexposed portion) and the background portion (completely exposed portion) obtained were measured as the densities of the initial sample with a Macbeth reflection densitometer. Next, in order to check the raw storability of the photosensitive paper, the heat-developable diazo copying material was stored in a packaged state at 50 ° C. for 72 hours, and a forced deterioration test was conducted.
After the deterioration test, the densities of the colored portion and the background portion were measured as in the initial sample. The results are shown in Table 1.

[0053]

[Table 1]

[0054]

As described above, according to the configuration described in the above first, without deteriorating the color developing property and the developing property,
A heat-developable diazo copying material excellent in raw storability is obtained.

According to the second construction, a heat-developable diazo copying material which is more excellent in raw storability can be obtained.

According to the constitution described in the above third aspect, a heat-developable diazo copying material further excellent in raw storability can be obtained.

According to the fourth construction, a heat developable diazo copying material having a higher color density can be obtained.

According to the structure described in the fifth aspect, as compared with the single-layer structure, partition walls are more likely to be formed between the layers, and the raw storability is easily improved.

[Table 1]

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B41M 5/18 112

Claims (5)

[Claims] 1. A heat-developable diazo copying material comprising a support having at least a diazo compound, a coupler, a basic substance and a eutectic agent attached thereto, wherein at least one component selected from the diazo compound, the coupler and the basic substance. A heat-developable diazo copying material, characterized in that a copolymer containing a monomer having a carboxyl group as a constituent is used as a binder of at least one component while encapsulating the above. 2. The heat-developable diazo copying material according to claim 1, wherein the copolymer is a styrene-acrylic acid copolymer. 3. The copolymer is a mixture of a styrene-acrylic acid copolymer and an isobutylene-maleic anhydride copolymer, and the mixing ratio thereof is in the range of 4: 1 to 1: 4 by weight. The heat-developable diazo copying material according to claim 1, wherein 4. The thermal transfer recording medium according to claim 1, wherein the eutectic agent has a melting point in the range of 80 to 150 ° C. 5. The heat-developable diazo according to claim 1, wherein the layer containing the diazo compound and the layer containing the coupler, the basic substance and the eutectic agent are laminated on a support. Copy material. [0001]