JPH0531480B2 - - Google Patents

Description

[Detailed description of the invention]

(A) Technical Field of the Invention The present invention relates to a photosensitive and thermosensitive recording medium, and more specifically, a diazonium salt that has excellent storage stability before being photodecomposed (hereinafter referred to as "raw storage stability"), and also has high sensitivity when heated. This invention relates to a photosensitive and thermosensitive recording medium that develops color. (B) Prior art and its problems Conventionally, when forming an image using a light and heat sensitive recording material, it is done in two ways. After image exposure using a fluorescent lamp or mercury lamp, infrared light,
There is a method of heating to about 50 to 200 degrees Celsius using a heat roller, high frequency, etc., and the other method is similar to general heat-sensitive recording materials, by using a heat pen, heat head, etc., on the light- and heat-sensitive recording material to print the above on the image. This is a method in which the unreacted diazonium salt in the non-image area is decomposed and fixed by heating the material to a high temperature and then irradiating the entire surface with ultraviolet rays using a fluorescent lamp or mercury lamp in the same way as with general diazo copying materials. Like the former, in applications similar to diazo copying materials, photosensitive and thermosensitive recording materials that require a high developing temperature of 150°C to 200°C during heat development use diazonium salts that have high heat resistance, which is disadvantageous for high-density images. In addition, it requires a high-temperature and high-precision heating device, so the heating temperature is between 50℃ and 150℃.
There is a need for a highly sensitive light- and heat-sensitive recording material that can provide sufficiently high color density at low temperatures. In addition, in recent years, high-speed thermal printing has been required in the field of thermal printers and facsimile machines, especially in applications similar to general thermal recording materials, such as the latter, and in this respect, there is also a demand for higher sensitivity in thermal color development. has been done. However, in general, there is a contradictory relationship between high sensitivity of heat color development and raw shelf life, and if you try to achieve high sensitivity of heat color development, the raw shelf life will deteriorate, and if you try to improve raw shelf life, heat color development will deteriorate. This tends to lead to lower sensitivity. The present inventors conducted research with the intention of providing a photosensitive and thermosensitive recording material that solved this problem, and first used a guanidine derivative having a specific general formula as a basic substance that promotes the reaction between a diazonium salt and a coupler compound. It has been discovered and proposed that a photosensitive and thermosensitive recording material with high sensitivity and excellent shelf life can be provided by the method. (Unexamined Japanese Patent Publication No. 57-45094, No. 57-125091
However, even in such photosensitive and thermosensitive recording materials, there has been an increasing demand for higher heat color development sensitivity in recent years, and if higher sensitivity is not achieved, there is a tendency for deterioration of raw shelf life, and even further raw shelf life is required. There was a need for improved technology. (C) Object of the Invention The object of the present invention is to overcome the above drawbacks and provide a photosensitive and thermosensitive recording medium with high sensitivity and excellent shelf life. (D) Structure and operation of the invention The present invention provides a photosensitive thermosensitive material containing as main components a fine particulate dispersion of a diazonium salt, a coupler compound, and a hydrophobic organic basic compound which is melted by heat and exhibits a basic atmosphere as a color developer. In a photosensitive and thermosensitive recording material having an undercoat layer provided between the layer and the support, the undercoat layer has a first-order dissociation constant of 10 ^-1 ~
The present invention relates to a light and heat sensitive recording material characterized by containing a polybasic acid of 10 ^-3 . Specific examples of the polybasic acid according to the present invention include citric acid, tartaric acid, malonic acid, maleic acid, oxalic acid, phthalic acid, dioxytartaric acid, etc., and by adding these compounds, the color development sensitivity is not reduced. The reason for the effect of improving raw shelf life is not clear, but when the organic basic compound is melted by heat and the pH of the light-sensitive and heat-sensitive layer increases, the acid that reduces color development sensitivity is released in the undercoat layer. Because it is present in the organic basic compound, it is difficult to cause a decrease in color development sensitivity, and on the contrary, during raw storage under high temperature and high humidity, part of the fine particulate dispersion of the organic basic compound dissolves, and the pH of the coating layer of the light and heat sensitive layer gradually increases. When there is a tendency to do so, it is thought that the buffering effect of the polybasic acid in the undercoat layer suppresses the increase in pH of the coating layer, improving shelf life. These acid compounds are preferably used in a weight ratio of 1.0 to 30%, more preferably 5 to 15%, based on the organic basic compound. If the amount of the acid compound added is less than the above-mentioned preferred range, the effect of improving raw storage stability will be weak, and if it is too much, it will cause a decrease in color development sensitivity. Further, in the undercoat layer, any binder or pigment commonly used in the field of thermal paper can be suitably used. The effects of the present invention can be observed not only when using hydrophobic guanidine derivatives but also when widely known organic basic compounds are used as color developers. Particularly preferred organic basic compounds include the following general formula (),
When used in combination with the guanidine derivative of the general formula (), a photosensitive and thermosensitive recording medium with high sensitivity and excellent storage stability can be obtained. General formula () General formula () [In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are hydrogen, alkyl having 18 or less carbon atoms, cyclic alkyl, aryl,
Represents aralkyl, amino, alkylamino, acylamino, carbamoylamino, heterocyclic residue,
R ₆ is lower alkylene, phenylene, naphthylene or

[Formula] (in the formula, X represents lower alkylene, SO ₂ , S ₂ , S, O, -NH- or a single bond), and aryl in the formula is a lower alkyl, alkoxy, nitro, acylamino, alkylamino group. and those having a substituent selected from halogen are also included. ] As the diazonium salt used in the present invention, any compound used in conventionally known diazo type copying materials can be used, but for example, the following compounds can be particularly preferably used. Specific examples include 4-N,N-dimethylaminobenzenediazonium chloride, 3-chloro-4-
N,N-dimethylaminobenzenediazonium chloride, 4-N,N-diethylaminobenzenediazonium chloride, 2,5-diethoxy-4-
N,N-diethylaminobenzenediazonium chloride, 4-N-ethyl-N-hydroxyethylaminobenzenediazonium chloride, 4-N,
N-diethoxyaminobenzenediazonium chloride, 4-phenylaminobenzenediazonium chloride, 4-N-(P-methoxyphenyl)-aminobenzenediazonium chloride, 4-morpholinobenzenediazonium chloride, 2,5-
Diethoxy-4-morpholinobenzenediazonium chloride, 4-oxazolidinobenzenediazonium chloride, 3-methyl-4-piperidinobenzenediazonium chloride, 4-ethylcapto-2,5-diethoxybenzenediazonium chloride, 4-tolyl Examples include mercapto-2,5-diethoxybenzenediazonium chloride and 4-benzylmercapto-2,5-dimethoxybenzenediazonium chloride. Further, as the coupler compound which reacts with the diazonium salt to form an azo dye, any compound capable of coupling with the above-mentioned diazonium salt can be used. Examples of these coupler compounds include phenol derivatives and oxynaphthalene derivatives, and compounds containing active methylene groups include the following compounds. (1) Phenol derivatives Pyrocatechol resorcin Phloroglycine Pyrogallol Meta-aminophenol Para-aminophenol Diethylaminophenol N-Lauryl-para-aminophenol N-Acyl-meta-aminophenol 3,3',5-trihydroxydiphenyl 3,3',5 , 5'-Tetrahydroxydiphenyl α-resorcinic acid β-resorcinic acid γ-resorcinic acid Phloroglucinic acid Gallic acid Diresorcin sulfide Diresorcin sulfoxide 3,5-Resorcinic acid ethanolamide 2,4-Resorcinic acid ethanol Amide 4-bromoresorcin 4-chlororesorcin 2-methylresorcin 3,3'-butylenedioxydiphenol 3,3'-ethylenedioxydiphenol bisphenol A (2) Oxynaphthalene derivative 2,3-dihydroxynaphthalene β- Naphthol α-Naphthol 1,6-dihydroxynaphthalene 2,3-dihydroxynaphthalene-6-sulfonic acid 2-naphthol-3,6-disulfonic acid 1,8-dihydroxynaphthalene-8-sulfonic acid 2-hydroxy-3- Naphthoic acid-N-β-hydroxyethyl-amide 2-hydroxy-3-naphthoic acid-N,N-bisβ-hydroxyethylamide 5-(paranitro)-penzamide-1-naphthol 1-naphthol-3-(N- β-hydroxyethyl)-sulfone-amide 2-hydroxy-3-propylmorpholino-naphthoic acid 2-hydroxy-3-naphtho-0-triidide 2-hydroxy-3-naphthoic acid morpholinopropylamide 2-hydroxy-3-naphthoic acid- 4'-chloroanilide 2-hydroxy-3-naphthoic acid-5'-chloro-2',4'-di-ethoxyanilide 2-hydroxy-3-naphthoic acid-2',5'-dimethoxyanilide 2-hydroxy- 3-naphthoic acid-2'-ethoxyanilide 2-hydroxy-3-naphthoic acid-2'-methoxyanilide 2-hydroxy-3-naphthoic acid-phenyl ester 2-hydroxy-3-naphthoic acid-4'-phenoxylate Cyanilide 2-hydroxy-3-naphthoic acid-4'-benzyloxyanilide 2-hydroxy-3-naphthoic acid-4'-phenethyloxyanilide 2-hydroxy-3-naphthoic acid-2'-benzyloxyanilide Anilide 2-hydroxy-3-naphthoic acid-2'-dimethylanilide 2-hydroxy-3-naphthoic acid-4'-methoxyanilide (3) Compound containing active methylene group 1-phenyl-3-methyl-pyrazolone (5) Acetoacetate anilide 1-Phenyl-3-carboxypyrazolone Acetoacetate Cyclohexylamide Acetacetate Benzylamide Cyanoacetanilide Cyanoacetomorpholin 4-Carboxy-acetoacetanilide These coupler compounds were processed using a ball mill, sand grinder, It can be contained in the light and heat sensitive layer as a fine particle dispersion with a particle size of 10 μm or less using a dispersion means such as an attritor. Further, one kind or a combination of two or more kinds of coupler compounds may be used to produce a dye exhibiting desired spectral absorption characteristics. Furthermore, during dispersion, the coupler compound may be dispersed alone, but it may also be co-dispersed with an organic basic compound or other additives if necessary. If the organic basic compound used as a color developer is soluble in the water used as a solvent for the coating solution when applied to the support, the pH of the coating solution will increase, causing fogging on the background and deterioration of storage stability. Therefore, it is desirable that it exists as a discontinuous fine particle dispersion in the coating layer.
In addition, if the solubility in water at 20°C is 1.0 g/or less, it has good humidity and heat storage stability, and heterocyclic compounds such as aliphatic amines, pyrrolidine derivatives, imidazole derivatives, imidazoline derivatives, and piperidine derivatives are also suitable. However, especially when hydrophobic guanidine derivatives of the following general formulas () and () are used as a color developer, image storage that has excellent storage stability under high temperature and high humidity conditions and develops color with high sensitivity. A diazo-fixed heat-sensitive recording material with excellent properties can be obtained. Also, the color developer has a melting point of 100 to 170℃.
Those within the range of can be particularly preferably used. The color developer may be dispersed alone using a dispersion means such as a ball mill, a sand grinder, an attritor, etc., but it may also be co-dispersed with a coupler compound and other additives as necessary. In addition, if necessary, polyvinyl alcohol,
Methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, sodium alginate, etc. are used as protective colloids to reduce the solid content during dispersion.
0.5-10% can be added. General formula () Or general formula () [In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are hydrogen, alkyl having 18 or less carbon atoms, cyclic alkyl, aryl,
Represents aralkyl, amino, alkylamino, acylamino, carbamoylamino, heterocyclic residue,
R ₆ is lower alkylene, phenylene, naphthylene or

[Formula] (wherein X represents lower alkylene, SO ₂ , S ₂ , S, O, -NH- or a single bond), and the aryl group in the formula is lower alkyl, alkoxy, nitro, acylamino, alkylamino and those having a substituent selected from halogen.] Typical examples are shown in Table 1, but the invention is not limited thereto. In the table

[Formula] represents a cyclohexyl group. These guanidine derivatives shown above can be easily synthesized by known methods or methods similar thereto. The light-sensitive and heat-sensitive layer of the present invention may be formed in a single layer on the undercoat layer, mainly containing a diazonium salt, a coupler compound, a color developer, etc., but the above-mentioned main components may be divided into two or multiple layers and placed on the undercoat layer. may be provided. Furthermore, if necessary, an acid compound or the like can be added as a pre-coupling inhibitor. Binder materials for forming the photosensitive and heat-sensitive layer of the present invention include corn starch, gum arabic, glue, gelatin, casein, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyacrylamide, carboxymethyl starch, dialdehyde starch, etc. starch or its modified products and derivatives, polyvinyl alcohol or its modified products and derivatives, polyvinylpyrrolidone, isobutylene-maleic anhydride copolymer, polyacrylate, styrene-maleic anhydride copolymer, polyvinyl chloride, polychloride vinylidene, polystyrene,
Synthetic resin emulsions such as styrene styrene butadiene rubber (=SBR), methacrylate butadiene rubber (=MBR), nitrile butadiene rubber (=NBR), polymethyl methacrylate, polypropylene, polyacrylonitrile, acrylic ester, etc. are listed, and these binders The materials can be used alone or in combination. Since the coupling reaction of diazonium salts is promoted in polar solvents such as water, the storage stability of fixed heat-sensitive recording materials using diazonium salts, especially under high temperature and high humidity conditions, is limited by the use of binder materials with a low equilibrium moisture content. It can also be greatly improved by selecting
Storage stability can also be improved by using water-resistant agents that are normally used in water-soluble polymeric binders, such as formalin, glyoxal, chromium alum, glutaraldehyde, melamine/formalin resin, and urea/formalin resin. I can do it. Specific examples of pigments used in the photosensitive and heat-sensitive layer of the present invention include kaolin, calcined kaolin, talc, waxite, diatomaceous earth, styrene resin particles, calcium carbonate, magnesium hydroxide, aluminum hydroxide, magnesium carbonate, Examples include titanium carbide, barium carbonate, urea-formalin filler, cellulose filler, aluminum oxide, etc., but from the viewpoint of thermal head matching properties such as scum and states king, JP-A No. 53-118059, 54-25845,
The oil absorption as described in 54-118846, 54-118847 is
80ml to 500 according to the measurement method specified in JIS K5101
It is preferable to use oil-absorbing pigments of ml/100g;
Particularly in the layer that is in direct contact with the heat head, it is desirable to use an oil-absorbing pigment exhibiting the above-mentioned oil absorption amount, such as calcined kaolin or urea-formalin filler. As other auxiliary ingredients, UV inhibitors and antioxidants such as thiourea may be added as necessary, and waxes and metal soaps may be used for the purpose of improving staining and coloring sensitivity. . Specifically, the waxes include paraffin wax, carnauba wax, microcrystalline wax, polyethylene wax, as well as higher fatty acid amides such as stearic acid amide, laurylamide, myristylamide, hardened tallow acid amide, palmitic acid amide, oleic acid amide,
Examples include acetamide, coconut fatty acid amide, methylolated products of these fatty acid amides, methylene bis stearamide, ethylene bis stearamide, and higher fatty acid esters. Examples of the metal soap include polyvalent metal salts of higher fatty acids, ie, zinc stearate, aluminum stearate, calcium stearate, zinc oleate, and the like. In addition, as a sensitizer that improves color development sensitivity, it has a melting point.
It is also possible to use a substance that has a temperature of 90°C to 150°C and has good compatibility with organic basic compounds, coupler compounds, etc. when heated. As these substances, any substance can be used as long as it has good compatibility during heating, but in particular substances that have a benzene ring or naphthalene ring in one molecule, as well as ether bonds, carbonyl groups (ketone groups, ester groups), etc. A substance having a polar group can be suitably used. Specific examples include dimethyl terephthalate, dibenzyl terephthalate, 1-methoxynaphthalene, 1,4-diethoxynaphthalene, and benzyl ether of P-hydroxybenzoic acid benzyl ester. It can be used alone or dispersed, but it can also be used co-dispersed with an organic basic compound, a coupler compound, etc. Further, a protective layer may be provided on the photosensitive and heat sensitive layer for the purpose of improving the water resistance, chemical resistance, and anti-glare properties of the image. In addition to paper, synthetic resin film,
Laminated paper etc. can also be used. (E) Examples Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Example 1 An undercoat layer was formed on a support with the following formulation:
The amount of coating after drying is 4.0g/ ^m2 .
The unit is parts by weight. Water 10g Oxalic acid 0.6g 10% polyvinyl alcohol 30g Calcined kaolin 10g Next, a coating liquid for the light and heat sensitive layer was prepared with the following composition, and the coating amount after drying on the undercoat layer was 9.0 g.
g/m ² and dried to create a light and heat sensitive recording material. Water 50g 2,5-diethoxy-4-morpholinobenzenediazonium tetrafluoroborate 2.0g Calcined kaolin 10g Part A 5g Part B 100g 10% polyvinyl alcohol 100g For parts A and B, mix the following compositions in a ball mill. Prepared by grinding for hours. Solution A 2-hydroxy-3-naphthoic acid-2'-methylanilide 10g 10% polyvinyl alcohol 5g Water 15g Solution B

[Formula] (Compound (7) in Table 1) 55g Stearamide 45g 10% methylcellulose 50g Water 150g Example 2 Example 1 except that citric acid was used instead of oxalic acid in the undercoat layer in Example 1.
A photosensitive and thermosensitive recording medium was prepared in the same manner as above. Example 3 A light and heat sensitive recording material was prepared in the same manner as in Example 1 except that sake soap was used instead of oxalic acid in the undercoat layer. Comparative Example 1 A photosensitive and thermosensitive recording material was prepared in the same manner as in Example 1 except that oxalic acid was not added to the undercoat layer. Comparative Example 2 In Example 1, no undercoat layer was provided,
A light and heat sensitive recording material was prepared using the same composition as in Example 1 for the light and heat sensitive layer. The photosensitive and thermosensitive recording material thus obtained was printed and recorded using Fujitsu's FACOM FAX 621C.
The diazonium salt was decomposed and fixed by full-surface ultraviolet exposure, and the color density was measured using a Macbeth densitometer (RD-514). In addition, as a moisture and heat resistance test to evaluate raw shelf life, the photosensitive and thermosensitive recording material prepared as described above was tested.
After being left at 40°C and 90% for 24 hours, the diazonium salt was photolyzed and the density of background fog was measured in the same manner as above.

[Table] (F) Effect of the invention The first-order dissociation constant between the support and the photosensitive/thermosensitive layer is 10 ^-1 ~
By containing a 10 ^-3 polybasic acid, a photosensitive thermosensitive material with high sensitivity and excellent shelf life could be obtained.

Claims (1)

[Scope of Claims] 1. A light- and heat-sensitive layer containing as main components a diazonium salt, a coupler compound, and a fine particulate dispersion of a hydrophobic organic basic compound that melts with heat and exhibits a basic atmosphere as a color developer, and a support. 1. A photosensitive and thermosensitive recording material comprising an intermediate undercoat layer, characterized in that the undercoat layer contains a polybasic acid having a first order dissociation constant of 10 ^-1 to 10 ^-3 . 2 The hydrophobic organic basic compound has the following general formula ()
The photosensitive and thermosensitive recording material according to claim 1, which is a hydrophobic guanidine derivative represented by (). General formula () General formula () [In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are hydrogen and the number of carbon atoms
represents an alkyl, cyclic alkyl, aryl, aralkyl, amino, alkylamino, acylamino, carbamoylamino, heterocyclic residue of 18 or less,
R ₆ represents lower alkylene, phenylene, naphthylene, or [Formula] (wherein X represents lower alkylene, SO ₂ , S ₂ , S, O, -NH-, or a single bond), and the aryl group in the formula is lower Also included are those having substituents selected from alkyl, alkoxy, nitro, acylamino, alkylamino groups and halogen. ]