JPH0324915B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a diazo-fixed heat-sensitive recording material that develops color with high density during heat-sensitive recording and has excellent image storage stability against light. In recent years, high-speed printers, facsimile machines, etc. have made remarkable progress in response to society's demand for outputting large amounts of information as hard copies as quickly as possible. Electrophotography, electrostatic recording, discharge recording, inkjet recording, thermosensitive recording, and the like are known as methods for forming images on recording media according to electrical information, such as high-speed printers and facsimiles. Among these methods, the thermal recording method has been rapidly becoming popular in recent years because the apparatus is relatively simple and the recording paper is also relatively inexpensive. As one method of the heat-sensitive recording method, a heat-sensitive recording sheet made by combining a color-forming substance such as crystal violet lactone and a phenolic compound such as bisphenol A is described in, for example, Japanese Patent Publication No. 14039/1983. and is already known. These thermosensitive recording sheets are currently widely used as office copy paper, recording paper for various recorders, electrocardiographs, calculators, computer terminals, facsimiles, and the like. However, with the above conventional method, if the background is heated incorrectly after printing, the background may become colored and the print may become unreadable, or there is a possibility that it may be tampered with after printing.
Improvements are strongly desired. The present inventors conducted research with the intention of providing a fixable heat-sensitive recording medium that solved this problem, and first developed 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 already been found and proposed that by using this method, it is possible to provide a fixable heat-sensitive recording medium that is highly sensitive and has excellent storage stability. (Unexamined Japanese Patent Publication No. 1983-
45094, Publication No. 57-125091). As a result of further development, the present inventors have found that at least one compound selected from the group of compounds represented by the following general formula () or (), and optionally (), is used as a coupler compound, especially with a particle size of 0.5. By using it in the form of a fine particle dispersion of ~10 microns, a diazo-fixed thermosensitive recording material with high sensitivity and excellent storage stability, as well as excellent image storage stability against light, was obtained. General formula () (However, X is selected from the group consisting of methylene, sulfide, and sulfoxide, and the aromatic ring may have an alkyl group, an alkoxy group, or a halogen as a substituent.) General formula () (However, Y and Z are hydrogen, halogen, alkano-
general formula () selected from the group consisting of (However, R ₁ to _{R 4} are each independently selected from the group consisting of hydrogen, an alkyl group, and an alkoxy group, and R ₅ is an alkylene group of 1 to 6 carbon atoms and a P-phenylene-bis-methylene group. ) The effect of improving image storage stability through the use of coupler compounds represented by general formulas () to () is due to the use of not only hydrophobic guanidine derivatives but also widely known organic basic compounds as color developers. However, by using guanidine derivatives of the following general formulas () and () as particularly preferred organic basic compounds, diazosols with high sensitivity, excellent storage stability, and excellent image storage stability can be obtained. A fixable thermosensitive recording medium is obtained. [In the formula, R ₆ , R ₇ , R ₈ , R ₉ and R ₁₀ are hydrogen, alkyl having 18 or less carbon atoms, cyclic alkyl, aryl,
Represents aralkyl, amino, alkylamino, acylamino, carbamoylamino, heterocyclic residue,
R ₁₁ 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 Also included are those having substituents selected from groups and halogens. ] As the diazonium salt used in the present invention, any compound used in conventionally known diazo type copying materials can be used. For example, compounds represented by the following general formulas (), (), () can be used. It can be used particularly preferably. In the formula, R ₁₂ and R ₁₃ are alkyl having 1 to 5 carbon atoms,
or alkoxyl, oxyalkyl, benzyl, substituted benzyl, benzoyl, substituted benzoyl, phenyl group, hydrogen atom, etc., and Y and Z
represents a halogen atom, alkyl having 1 to 5 carbon atoms, carboxyl, alkoxyl having 1 to 5 carbon atoms, nitro, acetoxy group, etc., and m and n represent 0 or a positive integer of 4 or less. Also, X is Cl ^- , Br ^- ,
It represents anions such as SO ₄ ⁻ , NO ₃ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ and ions to which ZnCl ₂ , CdCl ₂ or SnCl ₄ are added. 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,
Examples include N-diethoxyaminobenzenediazonium chloride, 4-phenylaminobenzenediazonium chloride, and 4-N-(P-methoxyphenyl)-aminobenzenediazonium chloride. In the formula, R ₁₄ is −CH ₂ CH ₂ OCH ₂ CH ₂ −ya−
CH ₂ OCH ₂ CH ₂ −, −CH ₂ CH ₂ CH ₂ CH ₂ −, etc. X, Y, Z, m and n have the same meanings as in the general formula (). Specific compound examples include 4-morpholinobenzenediazonium chloride, 2,5-diethoxy-4-morpholinobenzenediazonium chloride, 4-oxazolidinobenzenediazonium chloride, and 3-methyl-4-piperidinobenzene. Examples include diazonium chloride. In the formula, R ₁₅ represents an alkyl group or an aryl group.
Moreover, X, Y, Z, m and n have the same meanings as in the general formula (). Specific compound examples include 4-ethylcapto-
Examples include 2,5-diethoxybenzenediazonium chloride, 4-tolylmercapto-2,5-diethoxybenzenediazonium chloride, and 4-benzylmercapto-2,5-dimethoxybenzenediazonium chloride. In addition, an acid compound can be used in the photosensitive and heat-sensitive layer to stabilize the diazonium salt and prevent precoupling, but this is possible by using any organic or inorganic acid compound used in conventionally known diazo type copying materials. Specific examples include tartaric acid,
Citric acid, boric acid, lactic acid, gluconic acid, phosphoric acid,
Trichloroacetic acid, dichloroacetic acid, cyanoacetic acid, oxalic acid, malonic acid, maleic acid, etc. are all preferably used. 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. Specific examples of those corresponding to general formula () include the following. Table 1 Diresorcin Sulfide Diresorcin Sulfoxide Specific examples of compounds corresponding to general formula () include the following. Table 2 3,5-resorcinic acid ethanolamide 2,4-resorcinic acid ethanolamide 4-bromoresorcin 4-chlororesorcinol As specific examples of those corresponding to general formula (), the following can be mentioned. . Table 3 3,3'-ethylenedioxydiphenol 3,3'-ethylenedioxydiphenol 3,3'-ethylenedioxybis(2-methylphenol) 3,3'-ethylenedioxybis(2- methoxyphenol) 3,3'-ethylenedioxybis(2-methylphenol) 3,3'-ethylenedioxybis(2-ethoxyphenol) These coupler compounds were dispersed using a dispersion means such as a ball mill, sand grinder, or attritor. It can be incorporated into the light- and heat-sensitive layer as a fine particle dispersion with a particle size of 10 μm or less. In addition, the coupler compound has the above general formula () ~
One or more compounds selected from () may be combined, or if necessary, a yellow coupler having an active methylene group, a coupler having a pyrazolone ring, a β-naphthol derivative, etc.
() may be combined with compounds of () to produce dyes exhibiting desired spectral absorption properties. 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, it has excellent storage stability under high temperature and high humidity conditions, and also has image storage stability that develops color with high sensitivity. A diazo-fixed heat-sensitive recording material with excellent properties can be obtained. Further, as the color developer, one having a melting point in the range of 100 to 170°C 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. Or [In the formula, R ₆ , R ₇ , R ₈ , R ₉ and R ₁₀ 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 ₁₁ 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 It also includes those having substituents selected from groups and halogens.] Typical examples thereof are shown in Table 4, but are not limited thereto. In the table

[Formula] represents a cyclohexyl group.

【formula】

【formula】

【formula】 【formula】

These guanidine derivatives shown above can be easily synthesized by known methods or methods similar thereto. The light and heat sensitive layer of the present invention mainly contains a diazonium salt, a coupler compound, a color developer, etc. These may be provided as a single layer on a support as a light and heat sensitive layer, but the above main components may be formed in two layers or It may be divided into multiple layers and provided on the support. 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 butadiene rubber (=SBR), methacrylate butadiene rubber (=MBR), nitrile butadiene rubber (=NBR), polymethyl methacrylate, polypropylene, polyacrylonitrile, and acrylic ester are listed, and these binder 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, aluminum hydroxide, magnesium hydroxide, magnesium carbonate, Examples include titanium oxide, barium carbonate, urea-formalin filler, cellulose filler, aluminum oxide, etc., but from the viewpoint of thermal head matching properties such as scum and statesking, JP-A No. 53-118059, 54-25845,
The oil absorption as described in 54-118846, 54-118847 is
According to the measurement method specified in JISK5101, 80ml to 500ml/
It is desirable to use 100 g of an oil-absorbing pigment, and especially in layers that are in direct contact with the heat head, it is desirable to use an oil-absorbing pigment that exhibits the above-mentioned oil absorption in calcined kaolin, urea-formalin fillers, etc. Other auxiliary ingredients include zinc chloride, zinc sulfate, sodium citrate, etc. to suppress or assist color development.
Saccharides such as guanidine thiourea sulfate, calcium gluconate, sorbitol, and sugar rose are used, and if necessary, UV inhibitors and antioxidants are added, and waxes and metals are added to improve staining and color development sensitivity. You can use soap. 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. Metal soaps include higher fatty acid polyvalent metal salts, namely zinc stearate, aluminum stearate,
Examples include calcium stearate and zinc oleate. 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 both polar groups can be suitably used. Specific examples include dimethyl terephthalate, dibenzyl tephthalate, 1-methoxynaphthalene, 1,4-diethoxynaphthalene, and benzyl ether of P-hydroxybenzoic acid benzyl ester. Although these can be used alone as dispersed, they can also be used as co-dispersed with organic basic compounds, coupler compounds, etc. In addition to paper, synthetic resin film,
Laminated paper can also be used, and when paper is used as a support, if the photosensitive and heat-sensitive layer is applied directly onto the support, the diazonium salt will penetrate into the pores of the paper base and be impregnated into the inside, so a large amount of diazonium will be absorbed. Since salt is required, the sensitivity of light fixing due to exposure after thermal printing may be reduced. To prevent this drawback, if necessary, the paper base may be pre-filled with voids such as silica sol, alumina, titanium oxide, kaolin, etc. It may be precoated with a filler or a combination of these and a polymeric material such as starch, casein, polyvinyl alcohol, polyvinyl acetate emulsion, etc., and then a light and heat sensitive layer may be applied. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Example 1 A coating solution for a photosensitive and thermosensitive layer is prepared according to the following formulation, and coated onto a support so that the coating weight after drying is 9.5 g/m ² and dried to prepare a fixable thermosensitive recording material. The unit is parts by weight. Water 200 Oxalic acid 2.5 2,5-diethoxy-4-morpholinobenzenediazonium tetrafluoroborate 2 Calcined kaolin 10 Part A 5 Part B 100 10% polyvinyl alcohol 200 Parts A and B were prepared as follows in a ball mill. It was prepared by grinding for 48 hours. Liquid A diresorcin sulfide (compounds in Table 1)
10g 10% polyvinyl alcohol 5g Water 15g Liquid B

[Formula] (Compound (7) in Table 4) 55g Stearamide 45g 10% methylcellulose 50g Water 150g Example 2 In Example 1, instead of using compound (1) in Table 1 as liquid A, 4-bromlesorcin was used. A diazo-fixed heat-sensitive recording material was prepared in the same manner as in Example 1 except that (compound (3) in Table 2) was used. Example 3 In Example 1, diresorcin sulfide (compound (1) in Table 1) was used instead of using compound (1) in Table 1 in Solution A.
3g 3,3'-ethylenedioxydiphenol (Table-
In the same manner as in Example 1 except that 2 g of compound (1)) of No. 3 and 5 g of 2-hydroxy-2'-ethoxy-3-naphthoanilide were used in combination,
A diazo-fixed heat-sensitive recording material was prepared. Comparative Example 1 A fixable heat-sensitive recording material was prepared in the same manner as in Example 1 except that 2,4-dihydroxybenzoic acid was used instead of Compound (1) in Table 1 in Liquid A. Example 4 A photosensitive layer containing a diazonium salt was prepared with the following formulation, and the coating amount after drying on the support was 2.0 g/m ²
Apply it so that it looks like this. Oxalic acid 2g Thiourea 2g 2,5-diethoxy-4-morpholinobenzenediazonium tetrafluoroborate 2g Calcined kaolin 4g 10% polyvinyl alcohol 30g Water 100ml A heat-sensitive layer containing a color developer prepared with the following formulation on the above photosensitive layer The coating amount after drying is 8.0
g/m ² to prepare a diazo-fixed heat-sensitive recording material. Water 100g Calcined kaolin 20g Solution A 5g Solution B 100g 10% polyvinyl alcohol 120g 50% melamine formalin waterproofing agent 2g Solutions A and B were prepared by grinding and dispersing the following formulations in a ball mill for 48 hours. Liquid A diresorcin sulfide (compound (1) in Table 1)
10g 10% polyvinyl alcohol 5g Water 15g Liquid B

[Formula] (Compound (10) in Table 4) 55g Ethylene bisamide 45g 10% methyl cellulose 50g Water 150g Example 5 In Example 4, instead of using compound (1) in Table 1 as liquid A, 3,5- Example 4 except for using resorcinic acid ethanolamide (compound (1) in Table 2)
A diazo-fixed heat-sensitive recording material was prepared in the same manner as described above. Example 6 In Example 4, diresorcin sulfide (compound (1) in Table 1) was used instead of using compound (1) in Table 1 in Solution A.
3g 2,4-resorcinic acid ethanolamide (Table-
A diazo-fixed thermal recording material was prepared in the same manner as in Example 4 except that 2 g of compound (2)) and 5 g of 2-hydroxy-3-naphthoanilide were used. Comparative Example 2 A diazo-fixed thermosensitive recording material was prepared in the same manner as in Example 4, except that 2-methylresorcinol was used instead of Compound (1) in Table 1 in Liquid A. The diazo-fixed heat-sensitive recording material thus obtained was heated at 150° C. for 5 seconds to develop color using a heating block, and the entire surface was exposed to ultraviolet light to decompose the diazonium salt and fix it. The color image obtained in this way was measured using a xenon fade meter (manufactured by Suga Test Instruments, FAL-25X-HCL).
Table 5 shows the initial image density and image survival rate when irradiated for 24 hours at 40° C. and 60% at an irradiation intensity of 60 W/m ² . The measurement results were measured using a Macbeth densitometer (RD-514) using Kodatsu filter #106 for black pigment.

[Table] Example 7 Fixing was carried out in the same manner as in Example 4 except that 4,4-methylenebis-1,3-benzenediol was used instead of using compound (1) in Table 1 in Solution A in Example 4. A molded thermosensitive recording material was created. Example 8 A fixable thermosensitive recording material was prepared in the same manner as in Example 4 except that compound (2) diresorcin sulfoxide in Table 1 was used instead of compound (1) in Table 1 in Liquid A in Example 4. It was created. Example 9 Fixable thermosensitive recording was carried out in the same manner as in Example 4 except that 4-chlororesorcinol, compound (4) in Table 2, was used instead of compound (1) in Table 1 in Liquid A in Example 4. created a body. The results of Examples 7 to 9 are shown in Table 6.

【table】

Claims (1)

[Scope of Claims] 1. A light-sensitive and heat-sensitive layer containing as main components a fine particle dispersion of a diazonium salt, a coupler compound, and a hydrophobic organic basic compound which melts with heat and exhibits a basic atmosphere as a color developer is provided on a support. A diazo-fixed heat-sensitive recording material provided with a diazo-fixed heat-sensitive recording material having excellent image preservability, characterized in that the coupler compound is at least one compound selected from the group of compounds represented by the following general formula () or (). A diazo-fixed heat-sensitive recording material. General formula () (However, X is selected from the group consisting of methylene, sulfide, and sulfoxide, and the aromatic ring may have an alkyl group, an alkoxy group, or a halogen as a substituent.) General formula () (However, Y and Z are hydrogen, halogen, alkano-
2. The diazo-fixed heat-sensitive recording material having excellent image storage properties according to claim 1, characterized in that a coupler compound of the general formula () is used in combination as the coupler compound. General formula () (However, R ₁ to _{R 4} are each independently selected from the group consisting of hydrogen, an alkyl group, and an alkoxy group, and R ₅ is an alkylene group of 1 to 6 carbon atoms and a P-phenylene-bis-methylene group. ) 3 The hydrophobic organic basic compound has the following general formula ()
The diazo-fixed heat-sensitive recording material having excellent image storage properties according to claim 1 or 2, which is a hydrophobic guanidine derivative represented by (). [In the formula, R ₆ , R ₇ , R ₈ , R ₉ and R ₁₀ are hydrogen, alkyl having 18 or less carbon atoms, cyclic alkyl, aryl,
Represents aralkyl, amino, alkylamino, acylamino, carbamoylamino, heterocyclic residue,
R ₁₁ 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 represents lower Also included are those having substituents selected from alkyl, alkoxy, nitro, acylamino, alkylamino groups and halogen. ]