JPH0318598B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a fixable heat-sensitive recording material that develops color with high density during heat-sensitive recording and has excellent storage stability. 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. 2. Description of the Related Art Electrophotography, electrostatic photography, 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. has been described 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. We have already proposed that by using the method, it is possible to provide a fixable heat-sensitive recording medium with high sensitivity and excellent storage stability (Japanese Patent Application Laid-Open No. 57-45094,
Publication No. 57-125091). An object of the present invention is to provide a fixable heat-sensitive recording material that develops color with high density during heat-sensitive recording and has excellent storage stability. That is, the fixable heat-sensitive recording material of the present invention has a diazonium salt, a coupler compound, a coloring aid,
and a fixing type heat-sensitive recording material in which a fine particulate dispersion of an organic basic compound which is melted by heat and exhibits a basic atmosphere as a color developer is provided in the same layer or as a light- and heat-sensitive layer consisting of two or more separate layers. The method is characterized in that a naphthalene derivative represented by the following general formula () is used as a coloring aid. General formula () In the formula, R ₁ is a hydrogen atom, a halogen atom, an alkyl group, and R ₂ is a hydrogen atom, an alkyl group, a substituted alkyl group, or an aromatic group such as a phenyl group, a naphthyl group, a phenoxy group, or a naphthoxy group; Group groups include alkyl groups, aralkyl groups, alkoxy groups, aryloxy groups, acyl groups, aroyl groups,
It may have a substituent such as a nitro group or a halogen. Further, the naphthalene ring in the general formula can also have various substituents as described above. n=integer of 0, 1, 2, 3; m=integer of 1, 2, 3. The naphthalene derivative used in the present invention has a melting point of 40~
It is a solid substance at room temperature of 160℃, preferably 70 to 135℃, and is sparingly soluble or insoluble in water, and easily dissolves diazonium salts, coupler compounds, and organic basic compounds used as color developers when hot melted. It is preferable to use one that allows Specific examples of this naphthalene derivative are shown in Table 1 along with their melting points. Table-1 Compound Melting point 2-methoxynaphthalene 72℃ β-bromoethyl-β-naphthyl ether 96℃ 2,4-dinitrophenyl-β-naphthyl ether 95℃ P-tolyl-β-naphthyl ether 135℃ Benzyl-β-naphthyl ether 99 ℃ 2-α-naphthoxy-naphthalene 81℃ 2-β-naphthoxy-naphthalene 105℃ Glycerin-mono-β-naphthyl ether 110℃ Methylene glycol-di-β-naphthyl ether
133℃ β-chloroethyl-β-naphthyl ether 83℃ 2-(5-chloro-2-nitro-phenoxy)-naphthalene 110℃ 4-nitrobenzyl-β-naphthyl ether
106℃ Di-β-naphthyl ether 105℃ β,β′-di-β-naphthoxy-diethyl ether
122℃ Trimethylene glycol-mono-β-naphthyl ether 99℃ 1-α-naphthoxy-naphthalene 110℃ Ethylene glycol di-α-naphthyl ether
125℃ Trimethylene glycol di-α-naphthyl ether 103℃ Glycerin-mono-α-naphthyl ether 91℃ Ethylidene-di-α-naphthyl ether 117℃ The naphthalene derivatives shown above can be easily obtained by known methods or similar methods. It can be synthesized into The compound used as a coloring aid in the present invention is
All of them are thermofusible and poorly soluble or insoluble in water, and are used in the form of fine particles with a particle size of 0.1 to 10 μm.
The ratio of the diazonium salt, the coupler compound, and the color development aid of the present invention is preferably in the range of 1:(0.1-10):(0.1-20) (by weight). In addition, the coloring aid may be used alone or in combination with two if necessary.
More than one species can be used in combination. The effect of improving the color development sensitivity of a fixable heat-sensitive recording material by the color development aid of the present invention is observed not only when hydrophobic guanidine derivatives but also widely known organic basic compounds are used as a color developer, but this is particularly preferred. Examples of organic basic compounds include the following guanidine derivatives. In the formula, R ₃ , R ₄ , R ₅ , R ₆ and R ₇ 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 ₈ 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, but for example, compounds represented by the following general formulas (), (), and It can be suitably used. In the formula, R ₉ and R ₁₀ 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 ^-, etc., as well as ZnCl ₂ , CoCl ₂ , SnCl _4, etc., or ions added to these anions. 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 ₁₁ 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 ₁₂ 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 are dissolved in water or an organic solvent, or dispersed in a suitable solvent in the form of fine particles,
Preferably, it can be coated on the support within the range of 0.1 to 1.0 g/m ² . 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 5.0 to 100%, more preferably 10 to 50%, 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, and specific examples of these compounds include the following compounds. Phenol derivatives Pyrocatechol Resorcinol Phloroglycin Pyrogallol Meta-aminophenol Para-aminophenol Diethylaminophenol N-lauryl-para-aminophenol N-acyl-meta-aminophenol 3,3',5-trihydroxydiphenyl 3,3'5,5'-tetra Hydroxydiphenyl α-resorcinic acid β-resorcinic acid γ-resorcinic acid Phloroglucincarboxylic acid Gallic acid Oxynaphthalene derivatives 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-bis β-hydroxyethylamide 5-(paranitro)-benzamido-1-naphthol 1-naphthol-3-(N-β-hydroxyethyl)sulfone-amide 2-hydroxy-3-propylmorpholinonaphthoic acid 2 -Hydroxy-3-naphthoic acid-0-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, 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'-phenoxyanilide 2-hydroxy-3-naphthoic acid-4'-benzyloxyanilide 2 -Hydroxy-3-naphthoic acid-4'-phenethyloxyanilide 2-hydroxy-3-naphthoic acid-2'-benzyloxyanilide Compound containing active methylene group 1-phenyl-3-methyl-pyrazolone (5) Acetoacetyl acid anilide 1-Phenyl-3-carboxypyrazolone Acetoacetyl cyclohexylamide Acetoacetyl acid benzylamide Cyanoacetanilide Cyanoacetomorpholine 4-Carboxy-acetoacetanilide heterocyclic compound 1-(3'- sulfoamide)-phenyl-3-methyl-pyrazolone-5 1-(4'-carboxyethyl phenyl)-3-
Dodecyl-pyrazolone-5 These coupler compounds are dissolved in water or an organic solvent, or incorporated into 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 a ball mill or a sand grinder attritor. I can do it. 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, the color development aid of the present invention, or 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, 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 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, or the like, but it may also be co-dispersed with a coupler compound, the color development aid of the present invention, or other additives as necessary. [In the formula, R ₃ , R ₄ , R ₅ , R ₆ and R ₇ 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 ₈ 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. ] Typical specific examples are shown in Table 2, but the invention is 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. 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., 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 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-resisting agents such as formalin, glyoxal, chromium alum, glitaraldehyde, melamine/formalin resin, urea/formalin resin, etc., which are usually used in water-soluble polymer binder materials, may be used. However, it is possible to improve the storage stability. 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 are added, and waxes and metal soaps are added to improve staining and color sensitivity. It can be used. Specific examples of 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 amide, and palmitin. 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. Metal soaps include higher fatty acid polyvalent metal salts, namely zinc stearate, aluminum stearate,
Examples include calcium stearate and zinc oleate. These can be used alone as dispersed, but they can also be used as co-dispersed with organic basic compounds, coupler compounds, etc., and the color development aid of the present invention. 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 gel,
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 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. The mixture was prepared by pulverization and dispersion for 48 hours. Part A 2-hydroxy-3-naphthoic acid-2'-ethoxyanilide 10g Benzyl-β-naphthyl ether 10g 10% polyvinyl alcohol 5g Water 15g Part B

[Formula] (Compound (13) in Table 2) 100g 10% methylcellulose 50g Water 150g Example 2 In Example 1, instead of using benzyl-β-naphthyl ether in solution A, trimethylene glycol-mono-β-naphthyl ether was used. A fixable heat-sensitive recording material was prepared in the same manner as in Example 1 except for the use of 2-hydroxy-3-
A fixable heat-sensitive recording material was prepared in the same manner as in Example 1 except that 2-hydroxynaphthoic acid-4'-phenoxyanilide was used instead of naphthoic acid-2'-ethoxyanilide. Comparative example 1 In Example 1, benzyl-β of the present invention was used as liquid A.
- A fixable heat-sensitive recording material was prepared in the same manner as in Example 1 except that naphthyl ether was omitted. The thus obtained fixable heat-sensitive recording material was thermally printed using a facsimile machine (Toshiba KB-4800), and then the diazonium salt was decomposed 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). Table the value -
Shown in 3. Table 3 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. It is fixed and the skin density measured with a Macbeth densitometer is shown.
Shown in 3.

[Table] Example 4 A layer containing a diazonium salt is prepared according to the following formulation and coated on a support so that the coating weight after drying is 2.0 g/m ² . Oxalic acid 2g Thiourea 2g 2,5-diethoxy-4-morpholinobenzenediazonium tetrafluoroborate 2g Calcined kaolin 4g 10% polyvinyl alcohol 30g Water 100g Contains a color developer prepared with the following formulation on the layer created above. The coating amount of the coating layer after drying is
A fixing type heat-sensitive recording material is prepared by applying it at a concentration of 8.0 g/m ² . Water 100g Calcined kaolin 20g Part A 5g Part B 100g 10% polyvinyl alcohol 120g 50% melamine formalin waterproofing agent 2g For parts A and B, the same formulation as in Example 1 was ground and dispersed in a ball mill for 48 hours. Prepared. Example 5 A fixable heat-sensitive recording material was prepared in the same manner as in Example 4, except that the formulations of liquid A and liquid B were the same as in Example 2. Example 6 A fixable heat-sensitive recording material was prepared in the same manner as in Example 4, except that the formulations of liquid A and liquid B were the same as in Example 3. Examples 7-15 Instead of using benzyl-β-naphthyl ether, 2-methoxynaphthalene (Example 7), β-
Bromoethyl-β-naphthyl ether (Example 8), P-tolyl-β-naphthyl ether (Example 9), 2-α-naphthoxynaphthalene (Example
10), glycerin-mono-β-naphthyl ether (Example 11), β-chloroethyl-β-naphthyl ether (Example 12), 4-nitrobenzyl-β-
Naphthyl ether (Example 13), β,β′-di-β
Example 6 was repeated except using -naphthoxy-diethyl ether (Example 14) or trimethylene glycol-di-α-naphthyl ether (Example 1%). Comparative Example 2 A fixable heat-sensitive recording material was prepared in the same manner as in Example 4, except that the formulations of liquid A and liquid B were the same as in comparative example 1. The thus obtained diazo-fixed heat-sensitive recording material was thermally printed using a facsimile (Toshiba KB-4800), and then the entire surface was exposed to ultraviolet light to decompose and fix the diazonium salt. The print density obtained as described above was measured using a Macbeth densitometer (RD-514), and the values are shown in Table 4.
Shown below. Table 4 also shows the results of the storage stability test. The storage stability test consists of a moisture and heat resistance test in which the sample is prepared by preparing the coating solution, applied and dried, and left in a dark place at 40℃ and 90% relative humidity for 24 hours.
Table 4 shows the results of a heat resistance test in which the samples were left in a dryer at ℃ for 24 hours. After each treatment, the entire surface was exposed to light and fixed, and the background density was measured using a Macbeth densitometer.

【table】

【table】

Claims (1)

[Scope of Claims] 1. A fine particle dispersion of a diazonium salt, a coupler compound, a coloring aid, and an organic basic compound that melts with heat and exhibits a basic atmosphere as a color developer in the same layer or in two or more layers. A fixing heat-sensitive recording material provided on a support as a photosensitive heat-sensitive layer consisting of another layer, characterized in that the color development aid is a naphthalene derivative represented by the following general formula (). . General formula () In the formula, R ₁ is a hydrogen atom, a halogen atom, an alkyl group, and R ₂ is a hydrogen atom, an alkyl group, a substituted alkyl group, or an aromatic group such as a phenyl group, a naphthyl group, a phenoxy group, or a naphthoxy group; Group groups include alkyl groups, aralkyl groups, alkoxy groups, aryloxy groups, acyl groups, aroyl groups,
It may have a substituent such as a nitro group or a halogen. Further, the naphthalene ring in the general formula can also have various substituents as described above. n=integer of 0, 1, 2, 3; m=integer of 1, 2, 3. 2. Claim No. 1, in which at least one of the diazonium salt and the coupler compound is contained in the light and heat sensitive layer as a discontinuous fine particle dispersion.
The fixing type heat-sensitive recording material described in Section 1. 3. The fixable heat-sensitive recording material according to claim 2, wherein the organic basic compound is a hydrophobic guanidine derivative represented by the following general formula () or (). In the formula, R ₃ , R ₄ , R ₅ , R ₆ and R ₇ 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 ₈ 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.