JPH028915B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a fixable heat-sensitive recording material that has excellent storage stability and that develops color with high density during heat-sensitive recording. 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. It 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, 125091) As a result of further development, we developed hydrophobic guanidines of the general formulas () and () that contain a diazonium salt and a coupler compound on a support and, as a color developer, melt under heat to create a basic atmosphere. In a fixing heat-sensitive recording material provided with a light- and heat-sensitive layer containing a fine-particle dispersion of a derivative in the same layer, by containing at least one aromatic carboxylic acid derivative of the following general formula in the light- and heat-sensitive layer. The above object was achieved to a higher degree, and a fixable heat-sensitive recording material having high sensitivity and excellent storage stability was obtained. General formula () General formula () General formula () In the general formulas (), (), and (), l represents an integer of 1 to 4, m=0 or 1, n=0 or 1, m+n≦1, and the general formula () represents a 5- or 6-membered ring compound. In addition, the inventors of the present invention discovered that the effect of adding an aromatic carboxylic acid is observed not only when the hydrophobic guanidine derivative is used, but also when a widely known organic basic compound is used as a color developer. . Particularly preferred organic basic compounds include the following guanidine derivatives. 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 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. ] The addition ratio of the aromatic carboxylic acid derivative used in the present invention is 5% by weight to the organic basic compound.
It is desirable that the content be within the range of ~30%; if it is less than 5%, the effect of improving storage stability, which is the objective of the present invention, will be small, and if it is more than 30%, the color development sensitivity will decrease. Specific compounds of aromatic carboxylic acid derivatives used in the present invention are listed below. First, the benzoic acid derivatives included in the general formula () include 0-chlorobenzoic acid, 0-bromobenzoic acid, 0-nitrobenzoic acid, P-tertiarybutylbenzoic acid, trichlorobenzoic acid, salicylic acid, 5
-promosalicylic acid, 5-chlorosalicylic acid,
3.5-dichlorosalicylic acid, 3-isopropylsalicylic acid, 3-tertiarybutylsalicylic acid,
3.5-Diiodosalicylic acid, 3-Benzylsalicylic acid, 3.5-Ditiybutylsalicylic acid, 3
-(α-methylbenzyl)salicylic acid, 3.5-dinitrosalicylic acid, 5-t-butylsalicylic acid, 5
-sulfosalicylic acid, m-hydroxybenzoic acid,
P-hydroxybenzoic acid, 2-hydroxy-5-
Methoxy-benzoic acid, 4-hydroxy-3-methoxybenzoic acid, 5,5'-methylenedisalicylic acid, trimellitic acid, trimellitic anhydride. In addition, specific compounds of naphthoic acid derivatives included in the general formula () are listed as 7-glomo-3
-Hydroxy-2-naphthoic acid, 4.7-dipromo-3-hydroxy-2-naphthoic acid, 1-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, naphthalene-1.4.5.8-tetracarboxylic acid, etc. In addition, aromatic heterocyclic compounds included in general formula () include 2,6-pyridinecarboxylic acid, 3,4-pyridinedicarboxylic acid, pyridine-2-carboxylic acid, 2-thiophenecarboxylic acid, etc. can be mentioned. These aromatic carboxylic acid derivatives are added to the light and heat sensitive layer in a state dissolved in water or an organic solvent, or are dispersed to a particle size of 10μ or less using a dispersion means such as an attritor, a ball mill, or a sand grinder. It can be added to the light and heat sensitive layer as a fine particulate dispersion. The reason why the addition of the aromatic carboxylic acid derivative described above can improve storage stability without reducing color development sensitivity is probably due to the fact that it occurs during the dispersion of organic basic compounds and has a particularly large effect on the deterioration of storage stability. This is thought to be because the aromatic carboxylic acid derivative neutralizes the very fine dispersed particles or the dissolved matter in the dispersion solvent that gives the color, and also has some coupling ability itself, which can suppress the decrease in color development sensitivity. . Regarding the dispersion of the aromatic carboxylic acid,
Or by combining aromatic carboxylic acids,
Furthermore, organic basic compounds and coupler compounds,
If necessary, it can be used by co-dispersing with other compounds added in a dispersed state. 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, those represented by the following general formula can be particularly preferably used. In the formula, R ₁ and R ₂ are alkyl groups having 1 to 5 carbon atoms,
or an alkoxyl group, or an oxyalkyl group, a benzyl group, a substituted benzyl group, a benzoyl group, a substituted benzoyl group, a phenyl group, a hydrogen atom, etc., and Y and Z are a halogen atom, an alkyl group having 1 to 5 carbon atoms, a carboxyl group , an alkoxyl group having 1 to 5 carbon atoms, a nitro group, an acetoxy group, etc., and m and n are 0 or a positive integer of 4 or less.
Also, X is Cl ^- , Br ^- , SO ₄ ^- , NO ₃ ^- , ClO ₄ ^- , BF ₄ ^-
Anime phones such as ZuCl ₂ , Cdel ₂ or
It represents ions such as SnCl ₄ added to these anions. Specific examples include 4-N,N-dimethylaminobenzenediazonium chloride, 3-chloro-4-
N,N-dimethylaminobenzenediazonium chloride, 4-N,N-diethylaminobenzenediazonium chloride, 1,6-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 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 ₁ 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-ethylmercapto-2,5-diethoxybenzenediazonium chloride, 4-tolylmercapto-2,5-diethoxybenzenediazonium chloride, and 4-benzylmercapto-2,5-dimethoxybenzenediazonium chloride. and so on. These diazonium salts can be dissolved in water or an organic solvent, or dispersed in the form of fine particles in an appropriate solvent, and then coated on a support. 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. 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, oxynaphthalene derivatives, compounds containing active methylene groups, heterocyclic compounds, etc. Specific examples of these compounds include the following compounds. Phenol derivatives Pyrocatechol Resorcinol Chloroglycine 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 4-bromo-β-resorcinic acid Chloroglucincarboxylic acid Gallic acid oxynaphthalene derivative 2,3-dihydroxynaphthalene β-naphthol α-naphthol 1,6 -dihydroxynaphthalene 2,3-dihydroxynaphthalene-6-sulfonic acid 2-naphthol-3,6-disulfonic acid 2-hydroxy-3-naphthoic acid -N,N-bisβ-hydroxy-ethylamide 5-(paranitro)- Benzamide-1-naphthol 1-naphthol-3-(N-β-hydroxyethyl)-sulfone-amide 2-hydroxy-3-propylmorpholinonaphthoic acid 2-hydroxy-3-naphtho-O-toluidide 2-hydroxy-3- Naphthoic acid morpholinopropylamide 2-hydroxy-3-naphthoic acid-4'-chloroanilide 2-hydroxy-3-naphthoic acid-5'-chloro-2',4'-di-methoxyanilide 2-hydroxy-3-naphthoic acid-4'-chloroanilide 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 Compounds containing active methylene groups 1-Phenyl-3-methyl-pyrazolone (5) Acetoacetyl acid anilide 1-Phenyl-3-carboxypyrazolone Acetoacetyl cyclohexylamide Acetoacetyl acid benzylamide Cyanoacetanilide Cyanoacet Morpholine 4-Carboxy-acetoacetanilide heterocyclic compound 1-(3'-sulfoamido)-phenyl-3-methyl-pyrazolone-5 1-(4'-carboxyethyl phenyl)-3-dodecyl-pyrazolone-5 These Dissolve the coupler compound in water or an organic solvent, or use a dispersion means such as a ball mill, sand grinder, or attritor to obtain particles with a particle size of 10μ.
It can be contained in the light and heat sensitive layer as the following fine particulate dispersion. Further, two or more coupler compounds may be combined, if necessary, to produce a combination of dyes exhibiting desired spectral absorption characteristics. Further, during dispersion, the coupler compound may be dispersed alone, but it may also be co-dispersed with an organic basic compound, an aromatic carboxylic acid derivative, and other additives if necessary. If the organic basic compound used as a color developer is soluble in the water or organic solvent 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 to exist as a discontinuous fine particle dispersion in the coating layer, and the solubility in water at 20°C is 1.0.
g/ or less, the humidity and heat storage stability is good, and heterocyclic compounds such as aliphatic amines, pyrrolidine derivatives, imidazole derivatives, imidazoline derivatives, pipesozine derivatives, etc. can also be suitably used, but in particular, the following general formula () When the hydrophobic guanidine derivatives () and () are used as a color developer, it is possible to obtain a fixed heat-sensitive recording material which has excellent storage stability under high temperature and high humidity conditions and which develops color with high sensitivity.
Further, as the color developer, one having m·P 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, sand grinder, or attritor, but aromatic carboxylic acid derivatives, coupler compounds,
If necessary, it may be co-dispersed with other additives. General formula () or 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 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 specific examples thereof are shown in Table 1, but this does not limit the present invention. In the table

[Formula] represents a cyclohexyl group. These derivatives of quanidine shown above can be easily synthesized by known methods or methods similar thereto. In addition, examples of binder materials for forming the photosensitive and thermosensitive layer of the present invention include cornstarch, gum arabic, glue, gelatin, casein, methylcellulose, ethylcellulose, and aqueous solvents.
Starch or its modified products and derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose, polyacrylamide, carboxymethyl starch, dialdehyde starch, polyvinyl alcohol or its modified products and derivatives, polyvinylpyrrolidone, isobutylene-maleic anhydride copolymer, polyacrylic acid Salt, styrene-maleic anhydride copolymer, polyvinyl chloride, polyvinylidene chloride, polystyrene, styrene-butadiene rubber (=SBR), methacrylate-butadiene rubber (=
MBR), nitrile butadiene rubber (=NBR), polymethyl methacrylate, polypropylene, polyacrylonitrile, synthetic resin emulsion such as acrylic ester, etc. These binder materials can be used alone or in combination. Furthermore, in the case of an organic solvent system, the above-mentioned synthetic resin can be used by dissolving it in an organic solvent without emulsifying it. 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
In addition, when using an aqueous solvent, water-resistant agents such as formalin, glyoxal, chromium alum, glutaraldehyde, melamine/formalin resin, urea/formalin resin, etc., which are usually used in water-soluble polymer binder materials, can be used. Storage stability can be improved. 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, and carbonic acid. Magnesium, titanium oxide, barium carbonate, urea-formalin filler,
Examples include 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 and 54-118847 is JIS
80ml to 500ml/100 according to the measurement method specified in K5101
It is desirable to use oil-absorbing pigments having the above-mentioned oil-absorbing capacity, especially in layers that come into direct contact with a thermal head, such as 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 are added, and waxes and metal soaps are added to improve staining and color sensitivity. It can be used. Specific waxes include paraffin wax, carnauba wax, microcrystalline wax, polyethylene wax, and higher fatty acid amides such as stearic acid amide, laurylamide, myristylamide, hardened tallow acid gamide, and valmitin. Examples include acid amide, oleic acid amide, 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 metal soaps include polyvalent metal salts of higher fatty acids, ie, zinc stearate, aluminum stearate, calcium stearate, zinc oleate, and the like. These can be used alone as dispersed, but they can also be used as co-dispersed with organic basic compounds, aromatic carboxylic acid derivatives, coupler compounds and the like. 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, silica sol,
It may be precoated with a void filler such as alumina, titanium oxide, kaolin, etc., or a combination of these and a polymeric material such as starch, casein, polyvinyl alcohol, polyvinyl acetate emulsion, etc., and then a photosensitive/thermosensitive 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 tetrafluoroporate 2 Calcined kaolin 10 Solution A 100 Solution B 5 Solution C 10 10% polyvinyl alcohol 200 In addition, following solutions A, B, and C The following formulation was prepared by grinding and dispersing in a ball mill for 48 hours. Solution A 2-hydroxy-3-naphthoic acid-2'-ethoxyanilide 10g 10% methylcellulose 5g Water 15g

[Table] Example 2 In Example 1, instead of using 5-tertiarybutylsalicylic acid in liquid C, 1-hydroxy-2
- A fixable heat-sensitive recording material was prepared in the same manner as in Example 1 except that naphthoic acid was used. Example 3 A fixable heat-sensitive recording material was prepared in the same manner as in Example 1 except that trimellitic anhydride was used instead of 5-tertiarybutylsalicylic acid in Liquid C in Example 1. Example 4 A fixable thermosensitive recording material was prepared in the same manner as in Example 1 except that liquid D was used instead of liquid A, liquid E was used instead of liquid B, and liquid F was used instead of liquid C.

【table】

[Table] Example 5 A fixable heat-sensitive recording material was obtained in the same manner as in Example 4 except that trimellitic acid was used in place of 2,6-pyridine-dicarboxylic acid in the F solution. Comparative Example 1 A fixable heat-sensitive recording material was obtained in the same manner as in Example 1 except that liquid C was not added. The thus obtained fixable heat-sensitive recording material was thermally printed using a facsimile machine (Toshiba KB-4800), and then the diazonium salt was dispersed and fixed by exposing the entire surface to ultraviolet light. The print density obtained as described above was measured using a Macbeth densitometer (RD-514), and the values are shown in Table 2.
Shown below. Table 2 also shows the results of the storage stability test. The storage stability test represents the results of a humidity and heat resistance test when a sample formed by preparing a coating solution, applying it and drying it was left in a dark place at 40℃ and 90% relative humidity for 24 hours. After fixation, the skin density measured with a Macbeth densitometer is shown in Table 2.

【table】

Claims (1)

[Scope of Claims] 1. A photosensitive material containing a diazonium salt and a coupler compound on a support, and a fine particle dispersion of an organic basic compound which is melted by heat and exhibits a basic atmosphere as a color developer in the same layer. In a fixing type heat-sensitive recording material provided with a heat-sensitive layer, at least one aromatic carboxylic acid derivative of the following general formula is contained in the light-sensitive heat-sensitive layer.
A fixable heat-sensitive recording medium characterized by containing seeds. General formula () General formula () General formula () In the general formula (), (), (), l is an integer of 1 to 4 m=0 or 1 n=0 or 1 m+n≦1 General formula () represents a 5- or 6-membered ring compound. 2. The diazo-fixed thermal recording material according to claim 1, wherein the organic basic compound is a hydrophobic guanidine derivative represented by the following general formula () or (). General formula () General formula () [In the formula, R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ are hydrogen, alkyl having 18 or fewer carbon atoms, cyclic alkyl, aryl, aralkyl, amino, alkylamino, acylamino, carbamoylamino, heterocyclic residue , R ₆ is lower alkylene, phenylene, naphthylene or [Formula] (wherein X is lower alkylene, SO ₂ , S ₂ , S, O, -NH-
or a single bond), and the aryl group in the formula includes those having a substituent selected from lower alkyl, alkoxy, nitro, acylamino, alkylamino groups, and halogen. ]