JPH0444597B2 - - Google Patents

Description

[Detailed description of the invention]

(A) Technical Field 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. (B) Prior art and its problems 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 solving this problem and providing a fixable heat-sensitive recording material, 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). However, since a coupler compound that is generally used in the field of diazo copying paper is used, the azo dye produced has poor image preservation against light, and improvements in this respect have been sought. (C) Object of the Invention The object of the present invention is to provide a black coloring diazo-fixed heat-sensitive recording material which has improved the above-mentioned drawbacks and has high sensitivity and excellent storage stability of colored images. (D) Structure and operation of the invention A light-sensitive and heat-sensitive layer containing as main components a diazonium salt, a coupler compound, and a fine particle dispersion of an organic basic compound as a color developer that melts with heat and exhibits a basic atmosphere is provided on a support. In the diazo-fixed heat-sensitive recording material provided, the coupler compound is selected from a first coupler compound represented by the following general formula () and a second coupler compound group represented by the following general formulas () to (). At least one compound was used in combination, particularly as a fine particulate dispersion with a particle size of 0.5 to 10 microns. By adding a compound represented by the following general formula () to the diazo-fixed heat-sensitive recording material, a black-colored diazo-fixed heat-sensitive recording material with higher sensitivity and excellent image storage stability against light was obtained. General formula () (In the general formula (), R ₁ and R ₅ are both hydrogen atoms or one of them is a methyl group, and R ₂ , R ₃ , and R ₄ each represent a hydrogen atom, an alkyl group, and an alkoxy group. General formula () (However, R ₆ and R ₇ are each independently selected from the group consisting of hydrogen, an alkyl group, and an alkoxy group, and R ₈ represents an alkylene group having 1 to 6 carbon atoms. General formula () (However, X represents sulfide, 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 selected from the group consisting of hydrogen and halogen.) General formula () (However, R ₉ and R ₁₀ are hydrogen, an alkyl group having 1 to 6 carbon atoms, or R ₉ and R ₁₀ jointly form a cycloalkyl ring.) Image preservability by using the compound represented by the general formula () The improvement effect is observed not only when hydrophobic guanidine derivatives but also widely known organic basic compounds are used as color developers, but particularly preferred organic basic compounds include the following general formula (),
By using the guanidine derivative of the general formula (), a diazo-fixed thermosensitive recording material with high sensitivity and excellent storage stability, as well as excellent image storage stability, can be obtained. General formula () General formula () [In the formula, R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ and R ₁₅ represent hydrogen, alkyl having 18 or less carbon atoms, cyclic alkyl, aryl, aralkyl, amino, alkylamino, acylamino, carbamoylamino, heterocyclic residue; , R ₁₆ is lower alkylene, phenylene, naphthylene or

[Formula] (In the formula, 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. ] 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, compounds represented by the following general formulas (), (), () can be used particularly preferably. In the formula, R ₁₇ and R ₁₈ 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 added to these anions such as ZnCl ₂ , CdCl ₂ or SnCl ₄ . 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, etc. In the formula, R ₁₉ 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 examples of compounds include 4-morpholinobenzenediazonium chloride, 2,5-diethoxy-4-morpholinobenzenediazonium chloride, 4-oxazalidinobenzeneazonium chloride, 3-methyl-4-piperidino Examples include benzenediazonium chloride. In the formula, R ₂₀ 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. 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,
Trichloro acid, dichloro 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 15% to the organic basic compound. Specific examples of things that fall under the general formula () are:
For example, the following can be mentioned: Table 1 2-Hydroxy-2'-methyl-3-naphthanilide 2-hydroxy-2',4'-dimethyl-3-naphthanilide 2-hydroxy-2',5'-dimethyl-3-naphthanilide 2-hydroxy-2 ',3'-dimethyl-3-naphthanilide 2-hydroxy-2'-methyl-3'-methoxy-3-naphthanilide 2-hydroxy-2'-methyl-4'-ethoxy-3-naphthanilide 2-hydroxy-2'-Methyl-5'-ethoxy-3-naphthanilide2-hydroxy-3',4'-dimethoxy-3-
Naphthanilide 2-hydroxy-3',4',5'-triethoxy-3-naphthanilide 2-hydroxy-4'-ethoxy-3-naphthanilide 2-hydroxy-3',4'-diethoxy-3-
Naphthoanilide Further, as specific examples of those corresponding to the general formula (), the following can be mentioned. Table 2 3,3'-ethylenedioxydiphenol 3,3'-butylenedioxydiphenol 3,3'-ethylenedioxybis(2-methylphenol) 3,3'-ethylenedioxybis(2- methoxyphenol) 3,3'-ethylenedioxybis(6-methylphenol) 3,3'-ethylenedioxybis(6-ethoxyphenol) Specific examples of those corresponding to general formula () include the following: can be mentioned. Table 3 Diresorcin sulfide Diresorcin sulfoxide Specific examples of compounds corresponding to general formula () include the following. Table 4 3,5-Resorcinic Acid Ethanolamide 2,4-Resorcinic Acid Ethanolamide 4-Bromresorcin 4-Chlororesorcin Specific examples of those corresponding to general formula () include the following.

[Table] These compounds () to () may be contained alone or in a mixture in the light and heat sensitive layer as a fine particle dispersion with a particle size of 10μ or less using a dispersion means such as a ball mill, sand grinder, attritor, etc. I can do it. In addition, as long as the coupler compound is a combination of at least one compound selected from the above general formula () and general formulas () to () as a main component, a coupler having an active methylene group or a pyrazolone ring may be used as necessary. A dye exhibiting desired spectral absorption characteristics may be produced by combining couplers, β-naphthol derivatives, etc. Further, during dispersion, only the coupler compound may be dispersed alone, but it is also possible to co-disperse it with an organic basic compound 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, piperidine 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, a diazo-fixed heat-sensitive recording material is obtained which has excellent storage stability under high temperature and high humidity conditions, and which develops color with high sensitivity and has excellent image storage stability. I can do it. Also, the color developer has a melting point of 100
A temperature range of 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. General formula () Or general formula () [In the formula, R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ and R ₁₅ represent hydrogen, alkyl having 18 or less carbon atoms, cyclic alkyl, aryl, aralkyl, amino, alkylamino, acylamino, carbamoylamino, heterocyclic residue; , R ₁₆ is lower alkylene, phenylene, naphthylene or

[Formula] (In the formula, 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. 6, but is not limited to these. 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 and heat sensitive layer of the present invention has a diazonium salt, a coupler compound and a color developer as main components, and these may be provided as a single layer on a support as a light and heat sensitive layer. It may be divided into two parts and provided on the support body. 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 modified products and derivatives thereof such as hydroxyethyl cellulose, carboxymethyl cellulose, polyacrylamide, carpoxymethyl starch, dialdehyde starch, polyvinyl alcohol or modified products and derivatives thereof, polyvinylpyrrolidone, isbutylene-maleic anhydride copolymer, polyacrylic Acid acid, styrene-maleic anhydride copolymer, polyvinyl chloride, polyvinyldene 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., and 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 affected by the use of binder materials with a low equilibrium moisture content. 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 binders, may be used. However, it is possible to improve the storage stability. Further, specific examples of pigments used in the photothermal 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
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 comes into direct contact with the combustion 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. 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 are used to improve staining and color sensitivity. or metal soaps can be used. 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, meirolated products of these fatty acid amides, methylene bis stearamide, ethylene bis stearamide, and higher fatty acid esters. Examples of metal soaps include higher fatty acid polyvalent metals, 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 both polar groups 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. Although these can be used alone as dispersed, they can also be used as co-dispersed with organic basic compounds, coupler compounds, etc. As a support, 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 decrease.To prevent this drawback, if necessary, the entire paper 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 filler 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. (E) Examples Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Example 1 A coating solution for a photothermal layer is prepared according to the following formulation, coated on a support so that the coating weight after drying is 8.5 g/m ² , and dried to produce a diazo-fixed heat-sensitive recording material. . The unit is parts by weight. Water 200 Citric acid 2.5 2,5-diethoxy-4-morpholinobenzenediazonium tetrafluoroborate 2 Calcined kaolin 10 Part A 10 Part B 5 Part C 100 10% polyvinyl alcohol 200 Parts A, B, and C are as follows. The following formulation was prepared by milling in a ball mill for 48 hours.

[Table] Example 2 In Example 1, instead of using compound (1) in Table 1 and compound (1) in Table 3 as liquid A, 2-hydroxy-2',5'-dimethyl-3-naphthanilide was used. (Compound (3) in Table 1) 5g 3,3'-ethylenedioxyphenol (Compound (1) in Table 2) 3g was used, and instead of using Compound (2) in Table 5 in Solution C, ,

A diazo-fixed heat-sensitive recording material was prepared in the same manner as in Example 1 except that the compound (1) of Table 5 was used. Example 3 In Example 1, instead of using Compound (1) in Table 1 and Compound (1) in Table 3 as Liquid A, 2-hydroxy-2',3'-dimethyl-3-naphthanilide (Table 1) was used. Compound (4)) 5g 4-bromoresorcinol (Compound (3) in Table 4) 2g 3,3-ethylenedioxydiphenol (Compound (1) in Table 2) - instead of using compound (2) of 5

A diazo-fixed heat-sensitive recording material was prepared in the same manner as in Example 1 except that the following formula was used: Compound (3) in Table 5. Comparative Examples 1 to 3 In Examples 1 to 3 above, each of Example 1 is the same as Example 1 except that the dispersion liquid (Liquid C) of the compound contained within the range of the general formula () of the present invention is not added.
A diazo-fixed heat-sensitive recording material was prepared in the same manner as in steps 3 to 3. The diazo-fixed heat-sensitive recording material obtained in this way is heated at 150°C for 5 seconds and colored using a heating block to obtain a black colored image. Ta. The color image obtained in this way was measured using a xenon fade meter (manufactured by Suga Test Instruments, FAL-25X-HCL).
The table shows the initial image density and image survival rate when irradiated for 72 hours at 40℃ and 60% at an irradiation intensity of 60w/ ^m2 .
7. The measurement results were measured using a Macbeth densitometer (RD-514) using Kodatsu filter #105 for black pigment.

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Claims (1)

[Scope of Claims] 1. A photosensitive and thermosensitive layer containing as main components a diazonium salt, a coupler compound, and a fine particulate dispersion of an organic basic compound as a color developer which melts under heat and exhibits a basic atmosphere is provided on a support. A diazo-fixed heat-sensitive recording material, in which the coupler compound is selected from a first coupler compound represented by the following general formula () and a compound represented by the following general formula (), general formula (), and general formula (). A diazo-fixed heat-sensitive recording material containing at least one second coupler compound, characterized in that it contains at least one compound selected from the group of compounds represented by the following general formula (). A black coloring diazo-fixed thermal recording material with excellent image storage properties. General formula () (In the general formula (), R ₁ and R ₅ are both hydrogen atoms, or one of them is a methyl group, and R ₂ , R ₃ , and R ₄ each represent a hydrogen atom, an alkyl group, and an alkoxy group. ) General formula () (However, R ₆ and R ₇ are each independently selected from the group consisting of hydrogen, an alkyl group, and an alkoxy group,
And R ₈ represents an alkylene group having 1 to 6 carbon atoms. ) General formula () (However, X represents a sulfide, 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 selected from the group consisting of hydrogen and halogen.) General formula () (However, R ₉ and R ₁₀ are hydrogen, an alkyl group having 1 to 6 carbon atoms, or R ₉ and R ₁₀ jointly form a cycloalkyl ring.) 2. The organic basic compound has the following general formula () or () A black coloring diazo-fixing type thermal recording material having excellent image storage stability according to claim 1, which is a hydrophobic guanidine derivative represented by the following. General formula () General formula () [In the formula, R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ and R ₁₅ represent hydrogen, alkyl having 18 or less carbon atoms, cyclic alkyl, aryl, aralkyl, amino, alkylamino, acylamino, carbamoylamino, heterocyclic residue; , R ₁₆ 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. ]