JPH043317B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a photofixable heat-sensitive recording material containing a diazo compound and a coupler as thermochromic components. A basic heat-sensitive recording material (also called a heat-developable diazo copying material) that uses a diazo compound and a coupler as heat-coloring components is a substrate such as paper or plastic film, in which the active ingredients, that is, a diazo compound and a coupler, are mixed with an acidic substance. A heat-sensitive coloring layer is provided, which is dispersed in a binder together with ordinary auxiliary components such as basic substances and fillers. Further, in order to make it suitable for use in facsimile machines, electronic computers, and other high-speed recording devices, it is also known to add a thermofusible substance such as wax or wax as a color development aid or heat sensitivity improver. However, since water-soluble active ingredients coexist in the heat-sensitive recording layer of these heat-sensitive recording materials, there is a major drawback in that fogging is likely to occur, especially under high temperature and high humidity conditions. Therefore, British Patent No. 815005 proposes a heat-sensitive recording material having a three-layer structure in which the active ingredient is separated by an intermediate layer of a thermofusible substance, but it has not yet achieved a sufficient effect of improving storage stability. Further, US Pat. No. 3,111,407 proposes a heat-sensitive recording material in which one of the active ingredients is finely divided and encapsulated with a thermofusible substance, but this recording material has the disadvantage of reduced thermal sensitivity. Furthermore, Japanese Patent Publication No. 41-4146 proposes a heat-sensitive recording material in which the active ingredient is dispersed in the form of fine particles in a binder by coating it in the form of an organic solvent dispersion, but this method has the disadvantage of reduced photosensitivity. have. An object of the present invention is to provide a heat-sensitive recording material in which the water-soluble coupler is chemically treated to make it less soluble in water, thereby significantly improving the storage stability without reducing the heat sensitivity and photosensitivity. That is, the heat-sensitive recording material of the present invention is a heat-sensitive recording material in which a heat-sensitive coloring layer containing a diazo compound, a coupler, a thermofusible substance, and a binder is provided on a support, and the coupler includes a water-soluble coupler and a cationic surfactant. It is characterized by using a poorly water-soluble adduct obtained from.
The poorly water-soluble adduct used in the present invention is obtained by dissolving a water-soluble coupler and a cationic surfactant in water, mixing them, filtering out the precipitation caused by adding an alkali, and then mixing with water/ethanol. Obtained by recrystallization from a solvent. The water-soluble coupler used in the production of this poorly water-soluble adduct includes an aromatic ring having a hydroxyl group as shown in the following general formula, a condensed ring thereof, or a derivative thereof.

【formula】

【formula】

【formula】

【formula】

[Formula] [However, in general formulas () to (), R ₁ , R ₂ ,
R ₃ and R ₄ are hydrogen, hydroxyl group, amino group, carbon number 1
~4 alkyl group, alkoxyl group, dialkylamino group, X and Y represent an SO ₃ H group or SO ₃ M (M is an alkali metal),
n is a number of 0, 1 or 2. Also, R ₅ , R ₆ , R ₇
is hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group, a dialkylamino group, or a halogen. ] Specific examples of water-soluble couplers represented by these general formulas include phenol, 4-methoxy-1-naphthol, 4-amino-1-naphthol, 2-hydroxynaphthalene-6-sulfonic acid, resorcin, methylresorcin, phloroglucin, 4-
Examples include N,N-dimethylaminophenol, 5-methoxy-1,3-dihydroxybenzene, 2,5-dimethoxyphenol, 1,2-dihydroxybenzene, and 1,3-dihydroxy-4-chlorobenzene. On the other hand, examples of cationic surfactants include stearyltrimethylammonium chloride, laurylpyridinium chloride, lauryltrimethylammonium bromide, lauryltrimethylammonium chloride, octyltrimethylammonium bromide, laurylbenzyltrimethylammonium chloride, lauryldimethylbenzylammonium chloride, n-decyltrimethylammonium Bromide, n-decyltrimethylammonium chloride, oleyltrimethylammonium bromide, stearyltrimethylammonium bromide, cetyltrimethylammonium bromide, myristyltrimethylammonium bromide, stearyldimethylbenzylammonium chloride, cetyldimethylbenzylammonium chloride, myristyldimethylbenzylammonium chloride, stearyl dimethyl- 3,4-dichlorobenzylammonium chloride, lauryldimethyl-3,4-dichlorobenzylammonium chloride, stearyldimethyl-2-chlorobenzylammonium chloride, lauryldimethyl-4-chlorobenzylammonium chloride, etc. are suitable. The amount of poorly water-soluble addition salt used is 1 for the diazo compound.
Approximately 1 to 5 parts by weight per part by weight is appropriate. As the diazo compound used in the present invention,
A commonly used one, for example, one represented by the following general formula can be used. [However, in general formulas () to (), R ₁ ,
R ₆ and R ₈ are hydrogen, halogen, C ₁ to C ₅ alkyl group or alkoxyl group, or

[Formula] or

[Formula] (R ₁₁ , R ₁₂ : Same as R ₂ ), R ₂ , R ₃ , R ₉ are hydrogen, halogen, C ₁ to C ₅ alkyl group or alkoxyl group, R ₄ and R ₅ are the same or different _C1 - _C5 alkyl, hydroxyalkyl group, or

[Formula] (R ₁₃ : hydrogen, C ₁ to _{C 3} alkyl group or alkoxyl group, (or halogen), R ₇ is hydrogen, halogen, trifluoromethyl group, C ₁ to C ₅ alkyl group or alkoxyl group, or

[Formula] R ₁₀ is

【formula】

【formula】

【formula】

【formula】

[Formula] or

[Formula] (R ₁₄ , R ₁₅ , R ₁₆ : Same as R ₁₃ ), M ₁ , M ₂ , M ₃ are acid residues or acid residues forming a double salt with a metal salt. In this case, the acid residue is preferably a halogen ion or a fluorine-containing inorganic acid ion such as BF ^- ₄ or PF ^- ₆ , while the metal salt that forms a double salt with the acid residue is For example, ZnCl ₂ , CdCl ₂ , SnCl ₂
and so on. Y represents -CH ₂ - or -CO-,
n is 0 or 1. ] Specific examples of those corresponding to general formula () include the following. Specific examples of those corresponding to general formula () include the following. Specific examples of those corresponding to general formula () include the following. In order to further improve the storage stability, it is advantageous to use these diazo compounds in the form of water-insoluble salts such as fluorine-containing salts such as _-BF4 and _-PF6 . In the present invention, a thermofusible substance is used in order to enhance high-speed color development or heat sensitivity when used in facsimile or other high-speed recording equipment. Such a thermofusible substance preferably has a melting point in the range of 50 to 250°C. Below 50℃, the shelf life of the product tends to decrease, while above 250℃,
The thermal response of the product to the thermal head becomes insufficient. Specific examples of such thermofusible substances include the following. Alcohol derivatives such as 2-tribromoethanol, 2,2-dimethyltrimethylene glycol, and 1,2-cyclohexanediol, acid derivatives such as malonic acid, glutaric acid, maleic acid, and methylmaleic acid, and animals such as beeswax and Serratus wax. waxes, vegetable waxes such as carnauba wax, mineral waxes such as montan wax, paraffin wax, microcrystalline wax,
Other synthetic waxes, such as polyhydric alcohol esters of higher fatty acids, higher amines, higher amides,
Condensates of fatty acids and amines, condensates of aromatics and amines, synthetic paraffins, chlorinated paraffins, metal salts of higher fatty acids, higher linear glycols, dialkyl 3,4-epoxyhexahydrophthalates, and the like. These thermofusible substances are used in an amount of 2 to 30 parts by weight, preferably 5 to 10 parts by weight, per 1 part by weight of the diazo compound. If this amount is less than the above range, color development will be insufficient and the resulting product will be unsuitable as a recording material for high-speed recording. In the case of the present invention, it is particularly preferable to use 5 parts by weight or more for high-speed output recording such as facsimile. On the other hand, if the amount added is too large, blurring of the image may occur during color development by heating, which is undesirable. Therefore, in the case of the present invention,
The amount of the thermofusible material added is preferably kept within the above range. As the binder used in the present invention, all known binders in the field of thermal recording can be used, such as water-soluble resins such as gelatin, starch, hydroxyethyl cellulose, polyacrylic acid, carboxyethyl cellulose, methoxy cellulose, polyvinyl alcohol, and polyvinylpyrrolidone. Vinyl chloride~
Vinyl acetate copolymer, isobutylene-maleic anhydride copolymer, polystyrene, vinylidene chloride,
Examples include water-insoluble resins such as alkyd resins, polyvinyl butyral, and cyclized rubber. The appropriate amount of these binders to be used is about 5 to 70% of the weight of each layer. Further, in the present invention, the heat-sensitive coloring layer may further contain acidic substances, basic substances, fillers, and other substances as auxiliary components, if necessary. Acidic substance: Acidic substances are added as necessary to prevent coupling reactions and to maintain storage stability, and include, for example, the following. Tartaric acid, citric acid, boric acid, lactic acid, gluconic acid, sulfuric acid, etc. Basic substance: A basic substance is added as necessary to cause a coupling reaction during heating, and examples thereof include the following. Caustic alkalis and alkali carbonates such as sodium hydroxide, calcium hydroxide, potassium carbonate, etc.
Substances that generate basicity when heated include urea,
Thiourea and derivatives thereof, alkali salts of trichloroacetic acid, ammonium chloride, ammonium sulfate, ammonium citrate, etc. Filler: A filler is added to improve the matching property to a thermal head when heating with a thermal head, and examples of such fillers include the following. Organic and inorganic solid particles such as styrene resin particles, urea-formalin condensate resin particles, aluminum hydroxide, magnesium hydroxide, calcium carbonate, titanium, talc, kaolin, silica, and alumina. Other auxiliary ingredients include zinc chloride, zinc sulfate, sodium citrate, guanidine sulfate, calcium gluconate,
Sorbitol, satsuka rose, etc. are used. To make the heat-sensitive recording material of the present invention, the above components are basically mixed, dissolved or dispersed in a suitable solvent to form a coating solution, and this is used to coat paper, plastic film, synthetic paper, metal laminated paper, etc. The heat-sensitive coloring layer may be provided by coating and drying the coloring layer on the support. The heat-sensitive coloring layer thus obtained is a single layer type, but 2
It may be of a laminated type with more than one layer. In this case, the components used in each layer are arbitrary, and include, for example, those having the following configuration. Note that D is a diazo compound, C is a coupler, X is a thermofusible substance, and B is a binder, and the illustrated layers are provided on the support in order from the left. Further, the auxiliary component may be contained in each layer, or may be laminated as an independent layer at any position on the support together with a binder if necessary. Example 1 of laminated thermosensitive coloring layer B layer/(C+D+X+B) layer 2 (D+X+B) layer/(C+X+B) layer 3 (D+B) layer/X layer/(C+B) layer 4 (C+X+B) layer/(D+X+B) layer 5 ( C+X+B) layer/X layer (D+X+B) layer Among these, the examples 2) to 5) contain the diazo compound and coupler separately in separate layers, so the storage stability is lower than that of the single layer type or the example 1). However, the thermal sensitivity is slightly decreased. The solvent for dissolving or dispersing the above layer-forming components is appropriately selected and used depending on the properties and purpose of the layer to be formed. Examples of such solvents include water or alcohols such as methanol and ethanol, polar organic solvents such as methyl isobutyl ketone, methyl cellosolve, acetone, methyl ethyl ketone, and dimethyl ether, benzene, toluene, xylene, n-hexane, n-heptane, cyclohexane, and kerosene. or a mixture thereof. The heat-sensitive recording material of the present invention has excellent storage stability and high heat sensitivity, so it can be advantageously used in various heat-sensitive recording fields, especially for output recording in facsimile machines and electronic computers that require high-speed recording, and can be formed easily. This image has the advantage that unreacted diazo compounds can be decomposed and fixed simply by light irradiation. Examples of the present invention are shown below. Note that parts represent parts by weight. Example 1 An aqueous dispersion containing 1.5 parts of polyvinyl alcohol and 0.5 parts of calcium carbonate was coated on the surface of a high-quality paper weighing 20 g/m ² and dried to form an undercoat layer with a coating weight of 2 g/m ² . Apply a methyl cellosolve dispersion containing the following ingredients on top and dry it to determine the amount of adhesion.
A diazo layer of 3.35 g/m ² was applied. 0.35 parts Stearic acid amide 1.0 Vinyl chloride-vinyl acetate copolymer 2.0 Next, an aqueous dispersion consisting of the following components was applied on the diazo layer and dried to form a coupler layer with a coating weight of 2.5 g/m ² . The surface was arranged to have a Beck smoothness of 400 seconds to obtain a heat-sensitive recording material having a laminated heat-sensitive coloring layer. Imidazole 0.3 parts Adduct of phloroglucin and trimethylstearylammonium chloride 0.7〃 Silica 1.0 parts〃 Isobutylene-maleic anhydride copolymer 0.5〃 Next, this heat-sensitive recording material was printed with a commercially available high-speed recording facsimile, and then a commercially available diazo When the image was fixed by irradiating it with ultraviolet light using a copying machine, a clear black image was obtained. The image area density of this product was 1.0 using a Macbeth densitometer. Also copy this 40
Although it was left in an environment of ℃-90% RH for 24 hours, the skin concentration increased by only 0.10. Examples 2-3 Instead of the adduct of phloroglucin and stearyl ammonium chloride, an adduct of trimethylphloroglucin and dodecyltrimethylammonium chloride (Example 2) and an adduct of phloroglucin and laurylpyridinium chloride (Example 3) A similar type of heat-sensitive recording material was prepared in the same manner as in Example 1, except that each of the following was used. below,
When this recording material was used to print and record in the same manner as in Example 1 and was fixed, the image density was 0.95 and 0.97, respectively.
A clear black image was obtained. Furthermore, when these copies were left under the same conditions as in Example 1, the background density increased by only 0.09 and 0.12, respectively. Examples 4 to 7 Instead of the adduct of phloroglucin and stearyl ammonium chloride in Example 1, an adduct of 2-hydroxynaphthalene-6-sulfonic acid and stearyl trimethylammonium bromide (Example 4), 1,3-dihydroxy- Adduct of 4-chlorobenzene and lauryldimethylbenzylammonium chloride (Example 5), 4-methoxy-
An adduct of 1-naphthol and lauryldimethyl-4-chlorobenzylammonium chloride (Example 6) and an adduct of 2-hydroxynaphthalene-6-sulfonic acid and lauryldimethyl-4-chlorobenzylammonium chloride (Example 7) Printing was performed and fixed in the same manner as in Example 1 using the same type of heat-sensitive recording material as in Example 1, except that the image density was 0.98 (Example 4) and 1.02 (Example 4), respectively. Example 5), 0.94 (Example 6) 0.99
A clear black image of (Example 7) was obtained. Also,
These copies were left under the same conditions as in Example 1, but the background density increased by 0.10 (Example 4), 0.13 (Example 5), 0.09 (Example 6), and 0.12 (Example 7), respectively. Ta. Comparative Example A heat-sensitive recording material of the same type as in Example 1 was prepared, except that phloroglucin was used instead of the adduct of phloroglucin and trimethylstearylammonium chloride. The image density of this product after printing and fixing was 0.95, but the increase in background density after being left under the same conditions as in Example 1 was as large as 0.35.

Claims (1)

[Claims] 1. In a heat-sensitive recording material in which a heat-sensitive coloring layer containing a diazo compound, a coupler, a thermofusible substance, and a binder is provided on a support, the coupler is a poorly water-soluble coupler obtained from a water-soluble coupler and a cationic surfactant. A heat-sensitive recording material characterized by using an additive.