JPH0240516B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a heat-sensitive recording material using a heat-developable diazo type recording material that can be fixed (processing in which uncolored areas do not develop color due to heat). Conventionally, there are many known image recording methods for converting information into visible images. In general,
Images are formed by causing physical or chemical changes in response to energy such as light, radiation, electrolysis, magnetism, heat, or pressure. For example, there are two types of recording methods that use heat: one that forms images using physical changes such as melting, sublimation, and volatilization, and one that forms images that utilizes color development due to chemical changes caused by heat. . However, since such a heat-sensitive recording material is configured to obtain a recorded image using heat, the non-image area also has the ability to develop color when heat is applied later. Therefore, if it is mistakenly brought close to a heat source, it will develop color and lose its ability as a recording medium, which is a defect due to the structure of the thermal recording medium. Therefore, improvements in this respect are desired in the general market. Therefore, in recent years, a heat-developable diazo type recording material, which is a dry imaging system, has attracted attention as a heat-sensitive recording material, and development is progressing toward practical use. In a heat-developable diazo type recording medium, thermal developer undergoes chemical changes such as decomposition and melting due to heat energy, puts the recording layer in an alkaline atmosphere, causes azo coupling, and forms an image. A common method is to fix the non-image area by eliminating its thermal coloring ability. Although many patents have been issued using this method, there is currently no heat-developable diazo type recording material that fully satisfies storage stability and color development sensitivity. For example, a conventionally known heat-developable diazo type recording material is composed of the basic elements of a diazo compound, a coupling agent, an acid stabilizer, and a heat developer serving as an alkali source on a support. As thermal color developers, recording materials using base generators such as urea derivatives and guanidine derivatives that generate water-soluble ammonia, salts of organic amines and weak acids, and organic and inorganic ammonium salts will develop color. There are practical difficulties in terms of sensitivity, storage stability, and water resistance. Furthermore, a recording material using a base generator of a salt of a water-insoluble higher aliphatic amine and a polybasic acid as a thermal color developer has good storage stability, but has a problem in terms of color development sensitivity. Furthermore, recording materials using water-soluble salts such as halogenated acetates with high thermal decomposition rates, such as inorganic salts of trichloroacetic acid and lower aliphatic amine salts, as thermal color developers exhibit good color development sensitivity. , causing a pre-coupling phenomenon and poor storage stability. In other words, in heat-developable diazo type recording materials, those using water-soluble substances as thermal color developers have satisfactory color development sensitivity, but have poor storage stability; Both have advantages and disadvantages, as they have excellent storage stability but poor color development sensitivity. The present inventors have synthesized a large number of heat-developable color-developing substances for use in heat-developable diazo-type recording materials, and have worked diligently to invent heat-developable diazo-type recording materials that have excellent storage stability and good color development sensitivity. As a result of our research, we found that a heat-developable diazo-type recording material containing at least a water-insoluble higher aliphatic amine and a salt of trichloroacetic acid as a heat developer has unprecedented storage stability, color development sensitivity, and water resistance. We have discovered that this is the case, and have completed the present invention. The heat-developable diazo type recording material of the present invention basically consists of a support with a diazo compound, a coupling agent, an acid stabilizer, an antioxidant, a heat developer, and, if necessary, a polymer binder. It consists of a recording layer as an element. The thermal developer used in the recording medium has the general formula

[Formula] (However, R ₁ is a C ₁₂ to C 18 alkyl group, R 2 is a C 12 to _{C 18} alkyl group, and R ₂ is a C ₁₂ to C 18 alkyl group.
C ₁₈ alkyl group, methyl group or hydrogen atom; R ₃ represents a methyl group or hydrogen atom; and X represents trichloroacetic acid. ) is a water-insoluble salt of a higher aliphatic amine and trichloroacetic acid. The heat-developable diazo recording material of the present invention not only exhibits unprecedented storage stability, but also
Because it can be developed at temperatures below 130℃,
The support can be selected depending on the application. The above properties were achieved because the salt produced from a specific higher aliphatic amine and trichloroacetic acid as a thermal developer hardly dissolves in water and does not cause a decomposition reaction at temperatures below 100°C. A heat-developable diazo type recording medium using the same has good storage stability because it is not affected by the outside atmosphere (humidity and temperature) at room temperature and does not cause fogging. Furthermore, when the temperature approaches the melting point, it instantly thermally decomposes and contributes to development, resulting in high color development sensitivity. As described above, the heat-developable diazo type recording material according to the present invention has satisfactory storage stability and color development sensitivity, which have been difficult to put into practical use, and therefore can be used in various applications. For example, it is a particularly effective recording medium for computer output printers, data communication terminals, and for tickets, cards, and stickerless commuter passes that require counterfeit prevention. Each material used in the present invention will be described in detail below. The thermal developer used in the present invention is a salt formed from a water-insoluble selected higher aliphatic amine and trichloroacetic acid, such as dodecylammonium trichloroacetate, hexadecylammonium trichloroacetate, octadecylammonium trichloroacetate, and dioctylammonium trichloroacetate. Trichloroacetate, dioctadecylammonium trichloroacetate, icosyl ammonium trichloroacetate, N-methyl-N-
Dodecylammonium trichloroacetate, N
-Methyl-N-octadecylammonium trichloroacetate, N,N-dimethyl-N-octadecylammonium trichloroacetate, and the like. Also, the main component is the thermal developer used in the present invention,
In addition, a mixed system with a water-insoluble heat developer such as di(octadecyl ammonium) oxalate, di(octadecyl ammonium) tartrate, etc. is also effective. Various known diazo compounds can be used as the diazo compound used in the present invention. For example, paraphenylenediamine N-N-substituted compounds (4-diazo-N-N-diethylaniline, etc.), aminohydroquinone ethers (4-diazo-2-5-diptoxy-N-N-diethylaniline, 4-diazo-N-N-diethylaniline, etc.), diazo-2-chloro-5methoxy-N-benzoylaniline etc), aminodiphenyl, aminodiphenylamine and similar compounds (4-diazo-2-5
-4'-triexydiphenylamine, etc.), heterocyclic amine derivatives (4-diazo-2
-5-dibutoxy-N-phenylmorpholine
etc) etc. The diazo compounds described above are used as diazonium salts, which are relatively stable as sulfates or hydrochlorides, or as double salts with zinc chloride, boron trifluoride, and the like. As the coupling agent used in the present invention, any coupling agent that is normally used in dry diazo can be used. For example, resorcinol,
Phloroglucin, sodium 2,3-dihydroxynaphthalene-6-sulfonate, sodium 2-hydroxynaphthalene 3,6-disulfonate, 1
-(3-aminobenzamide)-4-naphthol, 1-(3-aminobenzacid)-7-naphthol, 2,3 dihydroxynaphthalene, 2,3
-dihydroxy-6-sulfanylnaphthalene,
Examples include 1-carboxy-2,3-dihydroxynaphthalene, 1,4-dichloro-2,3-dihydroxynaphthalene, 2,6-dihydroxybenzoic acid, and acetoacetanilide. As the acid stabilizer used in the present invention, various known nonvolatile acids can be used. Examples include citric acid, gluconic acid, tartaric acid, oxalic acid, sulfamic acid, boric acid, and phosphoric acid. Moreover, thiourea etc. can be used as an antioxidant. The polymer binder used in the present invention is used to improve the adhesion between the recording material and the support, the coating uniformity, or the water resistance. Even if it is not added, the characteristics of the recording medium of the present invention will not be impaired in any way. Examples of polymer binders include polyvinyl alcohol, hydroxyethyl cellulose, polyvinyl alcohol gum arabic, polyvinyl acetate emulsion,
Methyl cellulose, ethyl cellulose, polyvinyl butyral, polyvinyl acetate, polystyrene, nitrocellulose, cellulose acetate butyrate polymers and the like can be mentioned. Next, a known method can be used to coat the recording layer on the support in the present invention. Specifically, diazo compounds, couplers, acid stabilizers,
Coating by uniformly mixing a liquid in which a recording agent consisting of an antioxidant and, if necessary, a polymeric binder is dissolved in water or an organic solvent, and a pre-prepared dispersion containing a thermal developer. A heat-developable diazo type recording material can be produced by applying the solution onto a support such as paper, glass or film using a wire bar or the like and drying it at a low temperature. In addition, when the recording layer has a two-layer structure, a coating liquid in which a thermal color developer and a polymeric binder are uniformly dispersed in water or an organic solvent is applied onto the support using a wire bar or the like. After drying, a recording agent consisting of a diazo compound, a coupler, an acid stabilizer, an antioxidant and, if necessary, a polymeric binder is dissolved in water or an organic solvent and then applied with a wire bar or the like. By drying, a heat-developable diazo type recording material can be produced. However, some of the thermal color developers used in the present invention are soluble in organic solvents, so even if they are used in a solution type rather than as a dispersion, the characteristics of the recording medium of the present invention will not be affected in any way. It won't hurt. The method for recording the heat-developable diazo type recording material thus obtained can use a thermal head, thermal pen, infrared rays, laser light, etc. as a heat source. A mercury lamp, a tungsten lamp, a xenon flash, a laser, or the like is used as a light source that generates ultraviolet rays used for fixing. These heat sources and light sources can be used to develop and fix the heat-developable diazo type recording material. Examples of the present invention will be shown below. Example 1 A solution of 26.9 g of octadecylamine dissolved in 700 ml of commercially available primary ethanol was heated to a temperature of 50°C, and while stirring, a solution of 16.3 g of trichloroacetic acid dissolved in 50 ml of ethanol was gradually added dropwise. After the dropwise addition was completed, the mixture was stirred at the above temperature for 30 minutes. After the reaction is complete, lower the temperature to 0°C.
The white crystals formed are immediately filtered.
After thorough washing with cold ethanol solution and air drying, octadecyl ammonium trichloroacetate 38.0
I got g. Dispersion A A dispersion containing 10 g of octadecylammonium trichloroacetate and 100 ml of water/ethanol (9:1) was uniformly dispersed in a ball mill for 24 hours. B Solution P-N ₁ N-diethylaminobenzenediazonium chloride boron trifluoride double salt 1g Sodium 2,3-dihydroxynaphthalene-6-sulfonate 2g Tartaric acid 1g Thiourea 1g Polyvinyl alcohol 2g Water/ethanol (8:2) 100ml A A coating liquid made by uniformly mixing the dispersion liquid and B liquid at a ratio of 1:1 is applied onto pre-coated white paper using a No. 24 wire bar, dried at a low temperature, and heat-developed diazo type recording. Paper was made. When this recording paper was printed with a thermal printer and the entire surface was irradiated with a mercury lamp, a clear, deep-concentration blue-violet image was recorded. For comparison, a comparative heat-developed diazo Pattern recording paper was prepared and the color development sensitivity and storage stability were compared, and the following results were obtained.

[Table] As is clear from the results, the comparative product does not provide satisfactory color density and storage stability. Example 2 A solution prepared by dissolving 5 g of octadecylammonium trichloroacetate in a 2% ethanol solution of polyvinyl butyral was applied onto a polyester film using a No. 24 wire bar and dried. On the layer, P-N, N-diethylaminobenzenediazonium chloride zinc chloride double salt 1g, 2, 3
-2 g of sodium dihydroxynaphthalene-6-sulfonate, 1 g of oxalic acid, 0.7 g of thiourea and 2 g of polyvinyl alcohol were mixed with water/ethanol (1:
1) A recording film was prepared by applying the solution dissolved in 100 ml using a No. 24 wire bar and drying it. This recording film was passed through a transparent original closely, exposed to light with a mercury lamp to form a latent image, and then developed by irradiating the entire surface with infrared rays, resulting in a copy with a clear, dark blue-purple image. Obtained. Further, as in Example 1, a recording film with excellent preservability could be provided. Example 3 A solution of 28.3 g of N-methyl-N-octadecylamine dissolved in 700 ml of ethanol was heated to 50°C, and while stirring, a solution of 16.3 g of trichloroacetic acid dissolved in 60 ml of ethanol was gradually added dropwise. . After the dropwise addition was completed, the mixture was stirred at the above temperature for 30 minutes. After the reaction was completed, the temperature was cooled to 0° C., and the white crystals formed were immediately filtered, thoroughly washed with cold ethanol solution, and air-dried to obtain 37.5 g of N-methyl-N-octadecylammonium trichloroacetate. N-methyl-N-octadecylammonium trichloroacetate 5 produced as above
g, nitrocellulose-urethane (8:2) 5
g, toluene 70g, isopropyl alcohol 30g
A coating solution obtained by uniformly dispersing a mixed solution consisting of the above in a ball mill for 24 hours was applied onto a polyester film using a No. 24 wire bar and dried. On the layer, 5 g of alcohol-soluble cellulose acetate butyrate polymer, 1.5 g of 2,3-dihydroxynaphthalene, 2 g of 4-morpholino-2.5-dibutoxybenzenediazonium chloride boron trifluoride double salt, 0.3 g of oxalic acid, 80 g of methanol,
A mixed solution consisting of 10 g of butanol was applied using a No. 24 wire bar and dried to prepare a recording film. After printing on this recording film using a thermal printer, the entire surface was exposed using a xenon flash, and a clear, high-density blue image was obtained. Further, even when heat was applied to the unprinted area, no blue image was formed, and the result was that the image was fixed.

Claims (1)

[Claims] 1. A diazo compound, a coupling agent,
In a recording medium provided with a recording layer containing an acid stabilizer, an antioxidant, and a thermal developer, a salt of a water-insoluble higher aliphatic amine and trichloroacetic acid represented by the following general formula is used as the thermal developer. A heat-developable diazo type recording material characterized by the following. [Formula] (However, R ₁ is a C ₁₂ to C ₁₈ alkyl group, and R ₂ is a C ₁₂ to C 18 alkyl group.
C ₁₈ alkyl group, methyl group or hydrogen atom, R ₃
represents a methyl group or a hydrogen atom, and X represents trichloroacetic acid)