JPH0231675B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a heat-sensitive recording material, particularly a heat-sensitive recording material that can be fixed with light. That is, the present invention provides a diazo-based heat-sensitive recording material that develops color when recorded with a thermal head at a certain temperature, loses its ability to develop color in non-printed areas when irradiated with light, and does not recolor when heat is applied again. It is related to. In addition to being used as copy paper for books and documents, thermosensitive recording materials are also used as output recording paper for electronic computers, facsimile machines, medical measuring machines, etc., as well as thermal recording magnetic ticket paper and thermal recording label paper. be done. In addition, heat-sensitive recording materials are also being considered for use as paper for creating securities, gift certificates, admission tickets, certificates, slips, etc. by taking advantage of their ease of automatic recording. In order to obtain high recording reliability, the heat-sensitive recording material must be able to be fixed. Conventionally, as fixable heat-sensitive recording materials, diazo-based materials that utilize a color-forming reaction between a diazo compound and a coupler are known. However, from a practical standpoint, conventional products have not yet been satisfactory in terms of thermal response to thermal heads and long-term storage stability. In particular, in fields such as facsimile, high-speed recording performance (high-speed color development) is strongly required to reduce information transmission costs, but conventional diazo-based products
These requirements have not yet been fully satisfied. The present inventors have conducted extensive research to develop a material that differs from conventional diazo-based heat-sensitive recording materials in that it has excellent thermal responsiveness to a thermal head for high-speed recording, as well as excellent long-term storage stability. As a result,
The present invention has now been completed. That is, according to the present invention, a layer containing a porous filler is provided on a support as a precoat layer, and a diazo compound, a coupler, a thermofusible substance, and a thermofusible or thermosoftening material are applied thereon. A diazo-based heat-sensitive recording material capable of high-speed recording is provided, which is characterized by being provided with a heat-sensitive coloring layer containing a binder. In the present invention, by providing a precoat layer containing a porous filler on the support,
Preservation properties can be improved by preventing moisture absorption from the support of the thermosensitive coloring layer, and when the thermosensitive coloring layer is heated, the molten coloring substance is adsorbed by the porous filler in the precoat layer and penetrates into the support. Since this is prevented, high color development can be achieved. Therefore, the diazo heat-sensitive recording material of the present invention is different from conventional diazo heat-sensitive recording materials in that it is capable of high-speed recording and has excellent long-term storage stability. In addition, the heat-sensitive color forming layer as used in the present invention refers to one layer or a multilayer of two or more layers formed to support heat-sensitive color forming layer forming components such as a diazo compound, a coupler, and a thermofusible substance on a support. This means the entire coating layer. Therefore, the components for forming the thermosensitive coloring layer may be contained simultaneously in one coating layer, or appropriately separated and contained in two or more multilayer coating layers. As the diazo compound and coupler used in the present invention, those commonly used for diazo photosensitive paper are applicable, and examples thereof include those shown below. Diazo compound: 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 the general formulas [], [] and [], 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 group, 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】

【formula】

【formula】

【formula】

【formula】

【formula】

[Formula] (R ₁₄ , R ₁₅ , R ₁₆ : same as R ₁₃ ), M ₁ , M ₂ and 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 Examples include ZnCl ₂ , CdCl ₂ , and SnCl ₂ . Specific examples of those falling under the general formula [] include the following. Specific examples of those falling under the general formula [] include the following. Specific examples of those falling under the general formula [] include the following. In the present invention, in order to obtain a product with further improved long-term shelf life, HBF ₄ is used as the diazo compound.
Advantageously, it is used in the form of a water-insoluble salt such as a fluorine-containing salt such as or HPF ₆ . Couplers: Couplers used in the present invention include phenol, resorcin, methylresorcin, 4,4-bisresorcin, phloroglucin, resorcinic acid,
Phloroglucic acid, 2-methyl-5-methoxy-
1,3-dihydroxybenzene, 5-methoxy-
1,3-dihydroxybenzene, 4-N,N-dimethylphenol, 2,6-dimethyl-1,3,
5-trihydroxybenzene, 2,6-dihydroxybenzoic acid, 2,6-dihydroxy-3,5-
Phenol derivatives such as dibromo-4-methoxybenzoic acid, α-naphthol, β-naphthol, 4
-methoxy-1-naphthol, 2,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene-6-sulfonic acid sodium, 2-hydroxy-3
Examples include naphthol derivatives such as -propylmorpholinonaphthoic acid, 2-hydroxy-3-naphtho-O-toluidide, and 2-hydroxy-3-naphthoic acid morpholinopropylamide, but are of course not limited to these. However, any substance that can act as a coupler for the diazo compound can be applied. In the present invention, thermofusible or thermosoftening substances are preferably used in order to enhance rapid color development. Specific examples of such things include, for example, 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 selaz wax. waxes, vegetable waxes such as carnauba wax, mineral waxes such as montan wax, petroleum waxes such as paraffin wax and microcrystalline wax, and 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, 3,4
-Dialkyl epoxyhexahydrophthalate, etc. The thermofusible or thermosoftening substance used in the present invention preferably has a melting point or softening point in the range of 50 to 250°C. If the melting point or softening point is less than 50℃, the shelf life of the product tends to decrease,
When the temperature exceeds 250°C, the thermal response of the product to the thermal head becomes unsatisfactory. In addition, from the viewpoint of obtaining a product with high-speed coloring property (high-speed recording property), the thermofusible or heat-softening substance used in the present invention is preferably 2 to 30 parts by weight, based on 1 part by weight of the diazo compound. It is used in a proportion of 5 to 10 parts by weight. 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 or thermosoftening substance added is preferably kept within the above range. In the present invention, a heat-fusible or heat-softening binder is used in order to firmly support the heat-sensitive coloring layer on the support, but such binders include:
Examples include polyvinyl acetate, polyvinyl chloride, vinyl chloride/vinyl acetate copolymer, polyacrylic acid ester, polystyrene, polybutadiene, polyacrylamide, styrene/butadiene/acrylic copolymer, and the like. These binders preferably have a melting point or softening point in the range of 50 to 250°C. 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 heated by 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. In the present invention, as the binder, thermofusible or thermosoftening binders as described above are preferably used, but these binders do not necessarily need to be used alone, and each component in the layer is Other binders may be used in combination to firmly bind to the support. Examples of such binders include the following. polyvinyl alcohol, polyacrylamide,
casein, gelatin, starch and its derivatives,
Polyvinylpyrrolidone, carboxymethylcellulose, methylcellulose, ethylcellulose, polyester (≒100,000 or more), polystyrene (≒100,000 or more), chlorinated rubber, styrene-maleic anhydride copolymer, iso(or diiso)butylene-maleic anhydride copolymer Water-soluble urea-formalin resin, phenol resin, melamine resin, etc.
Organic solvent soluble or aqueous dispersion resin. These binders may be used alone in some cases. In the present invention, a precoat layer containing a porous filler is formed on the support prior to the formation of the heat-sensitive coloring layer. In this case, the porous filler may include various inorganic and organic fillers. However, in general, oil absorption (JISK 5101
(based on) is 100ml/100g or more, preferably 200
~500ml/100g of material is used. Examples of such porous fillers include the following. The number in brackets after the substance name below indicates the oil absorption amount. Diatomaceous earth (100-160), anhydrous aluminum oxide (100-250), titanium oxide (100-120), magnesium carbonate (100-150), silica (100-800), magnesium aluminosilicate (300-400), zeolite (100-1000), urea-formalin resin fine particles (100-500), etc. A binder is applied to the precoat layer containing the porous filler in order to firmly adhere it to the support. Used arbitrarily. Formation of this precoat layer also helps to prevent the staking phenomenon during thermal printing. Furthermore, in the present invention, a heat-resistant polymer resin coating is provided on the heat-sensitive coloring layer as necessary to prevent moisture absorption from the surface of the heat-sensitive coloring layer, improve storage stability, and enhance head matching properties. It is also possible. In this case, the heat-resistant polymer resin has a melting point, softening point, or decomposition point of 200℃ or higher,
Examples include carboxyl group-modified polyvinyl alcohol, hydroxyethyl cellulose, polyester, polycarbonate, and the like. To produce the diazo-based heat-sensitive recording material of the present invention, the porous filler described above is dispersed in the form of solid particles in a solvent such as water, toluene, methyl isobutyl ketone, methyl cellosolve, n-hexane, or cyclohexane. to prepare a precoat layer coating solution. Next, the coating liquid is applied to a support such as paper, synthetic paper, plastic film, etc. so that the solid content is 1 to 100 g/m ² and dried to form a precoat layer. Next, the aforementioned diazo compound, coupler, thermofusible substance, and other auxiliary components used as necessary are dissolved or dispersed in a solvent such as water, toluene, methyl isobutyl ketone, methyl cellosolve, or n-hexane. A heat-sensitive coloring layer coating solution is prepared, and this coating solution is applied onto the precoat layer so that the solid content is 1 to 10 g/m ² and dried. The heat-sensitive recording material of the present invention can be advantageously applied in various heat-sensitive recording fields, particularly as output recording paper for facsimile machines and electronic computers that require high-speed recording.Moreover, in the case of the present invention, the surface Characters and images recorded on the film can be fixed by forming the image by heating and then decomposing the unreacted diazo compound with light. Also,
The heat-sensitive recording material of the present invention utilizes its fixing properties,
It can be applied to recording and creating necessary information for securities, gift certificates, admission tickets, certificates, slips, etc. Next, the present invention will be explained in more detail with reference to Examples. Example Part A: Silica 5 parts by weight 10% polyvinyl alcohol aqueous solution 5 Water 90 Part B: 2-hydroxy-3-propylmorpholino-naphthoic acid 3 parts by weight Stearic acid amide 5 Urea 10 10% polyvinyl alcohol aqueous solution 20 〃Wed 62 〃

【table】

[Table] Solution E: Sodium 2,3-dihydroxynaphthalene-6-sulfonate 3 parts by weight Urea 10 Boric acid 0.5 Water 82.5 After ball mill dispersion, polyvinyl acetate emulsion (solid content 50%) 4 parts by weight Add and stir evenly. Liquid F: Stearic acid amide 5 parts by weight Polystyrene resin (≒800) 1 〃 Toluene 94 〃

[Table] The above compositions A to G were prepared using a ball mill for 24 hours.
Dispersions A to G were prepared by time-pulverization and dispersion.

[Table] The coating solutions of Examples 1 to 3 and Comparative Examples 1 and 2 described above were applied to the surface of high-quality paper (approximately 50 g/m ² ), and the adhesion amount of each layer was 2 to 3 g/m ² (solid content ) was provided with a precoat layer and a heat-sensitive coloring layer, and further calendered to obtain a heat-sensitive recording material with a Beck smoothness of 400 seconds. The heat-sensitive recording material obtained as described above was printed in G-mode using RIFAX 303 (manufactured by Ricoh Co., Ltd.), and then completely exposed using Ricopy High Start 205 (manufactured by Ricoh Co., Ltd.). It took root. Next, Table 1 shows a quality comparison of Examples 1 to 3 and Comparative Examples 1 and 2.

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Claims (1)

[Claims] 1 A layer containing a porous filler is provided as a precoat layer on a support, and a heat-sensitive layer containing a diazo compound, a coupler, a heat-fusible substance, and a heat-fusible or heat-softening binder is applied thereon. A diazo-based heat-sensitive recording material characterized by being provided with a coloring layer.