JP2002113952A - Thermal recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal recoding material excellent in coloring sensitivity and the resistance to heat and a plasticizer. SOLUTION: The thermal recording material contains, on a substrate, a colorless or light-colored basic dye and at least one kind of sulfone-series developer expressed by general formula (1) [wherein R1 and R2 denote a C1-8 alkyl, alkoxy, alkenyl or aryl or a halogen group, A hydroxyl, alkyl, alkoxy, alkenyl or aryl or an electron absorbing group and a, b and c integers of 0-3] as a developer capable of developing a color in contact with the dye, and at least one kind of phenylbenzylsulfone derivative expressed by a general formula (2) [wherein R3 and 4 denote a C1-4 alkyl, alkoxy, alkenyl or aryl group respectively and n and m integers of 0-2] as a sensitizer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material having excellent coloring sensitivity, heat resistance and plasticizer resistance.

[0002]

2. Description of the Related Art In general, a heat-sensitive recording material having a heat-sensitive color-forming layer mainly composed of a colorless or light-colored dye precursor and a color developer which reacts with the dye when heated to form a color is disclosed in JP-B-45-14.
No. 039, which is widely used. In order to perform recording on this heat-sensitive recording material, a thermal printer or the like having a built-in thermal head is used, but such a heat-sensitive recording method has less noise at the time of recording as compared with other recording methods that have been practically used conventionally. Developing and fixing are not required, maintenance-free, equipment is relatively inexpensive, compact, and the obtained color is very sharp. With the development of the information industry, facsimile and computer fields, Although widely used for measuring instruments, labels, and the like, as recording devices become more diversified and have higher performance, the required quality of heat-sensitive recording materials has become higher. As for the recording speed, as the size of the apparatus is reduced and the recording speed is increased, it is required that a clear color image with a high density can be obtained even with minute heat energy. In order to satisfy such requirements, for example, a method of increasing the color sensitivity by adding a heat-soluble substance to a heat-sensitive layer as described in JP-A-56-169087, and JP-A-56-144193. A method has been devised to increase the color development sensitivity by a method using a new color developing agent having a high color developing ability as described in, but any heat-resistant ground color deteriorates, It has been difficult to say that it has sufficient quality because it has drawbacks such as a decrease in color density (reprintability) when printing after storing uncolored portions for a long time. In addition, a method in which an appropriate sensitizer is further used in combination with a dye and a developer, for example, bisphenol is used as the developer.
When composed of a phenolic compound represented by A, p-
Benzylbiphenyl (JP-A-60-82382), p
-Benzyl benzylhydroxybenzoate (JP-A-57-
201691), benzyloxynaphthalene (JP-A-58-87094) and the like are used as suitable sensitizers. As a method for increasing the color development sensitivity of the sulfone color developer used in the present invention, JP-A-4-69283 discloses a method of adding di (p-methylbenzyl) oxalate, and JP-A-8-67070 discloses a method of increasing the color development sensitivity. Although the content of adding a solid solution of various oxalate derivatives is described, it is hard to say that although the coloring sensitivity is somewhat increased, the image stability over dusting and aging is sufficient. As described above, the color-forming ability is insufficient to satisfy the recent demand for high sensitivity, and a heat-sensitive recording material having another quality performance while realizing high sensitivity has not yet been obtained.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material which is excellent in color sensitivity, heat resistance and plasticizer resistance.

[0004]

SUMMARY OF THE INVENTION The present invention provides a method for manufacturing a semiconductor device comprising the steps of:
A colorless or pale-colored basic dye and a developer capable of forming a color upon contact with the dye represented by the general formula (1)

[0005]

Embedded image

[Wherein R ₁ and R ₂ represent a C1 to C8 alkyl group, alkoxy group, alkenyl group, aryl group or halogen group. A represents a hydroxyl group, an alkyl group, an alkoxy group, an alkenyl group, an aryl group, or an electron withdrawing group. a, b, and c represent an integer of 0 to 3. And at least one sulfone developer represented by the general formula (2):

[0007]

Embedded image In the formula, R ₃ and R ₄ each represent a C1 to C4 alkyl group, alkoxy group, alkenyl group, or aryl group.
n and m show the integer of 0-2. These problems are intended to be solved by including at least one phenylbenzylsulfone derivative represented by the following formula:

It is generally assumed that the color development sensitivity of a heat-sensitive recording material is affected by the melt-dissolution rate and saturation solubility of the dye and the developer. In order to improve these, it is known to add various materials as sensitizers, and the addition of the sensitizer lowers the melting point, changes the polarity, lowers the activation energy, and improves the compatibility between the materials. It is thought that many factors work in a complicated manner, and the melt-dissolution diffusion rate and the saturation solubility increase, thereby promoting the improvement of the color sensitivity. The reason why the excellent effects are obtained in the present invention is not clearly elucidated, but by using a sulfone-based developer as a developer, and by including a phenylbenzylsulfone derivative,
It is thought that the coloring sensitivity of the heat-sensitive recording material is improved without causing a significant drop in the melting point.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In order to obtain the heat-sensitive recording material of the present invention, for example, a dye, a compound represented by the general formula (1) or a compound represented by the general formula (2) are mixed, and other necessary additives are added thereto. The thermosensitive recording material of the present invention can be produced by preparing a thermosensitive coloring layer by preparing a coating solution for the coloring layer and coating and drying the coating solution on the substrate. In the present invention, a sulfone-based developer represented by the general formula (1) is contained as a developer. When the compound represented by the general formula (1) is specifically exemplified,
4'-bisphenolsulfone, 2,4'-bisphenolsulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 3,3'-dimethyl-4,4'-dihydroxydiphenylsulfone, 3,3 ', 5 5'-tetramethyl-4,4'-dihydroxydiphenylsulfone, 2,2'-bis (4-chlorophenol) sulfone, 4-hydroxy-3'-isopropyl-4'-hydroxyphenylsulfone, bis (3-ethyl -4-hydroxyphenyl) sulfone, 2,2'-bis (p-tert-butylphenol) sulfone, 2,2'-bis (p-
Tertiary pentylphenol) sulfone, 2,2'-bis (p-tert-octylphenol) sulfone, 4-hydroxy-4'-isopropoxydiphenyl sulfone,
-Hydroxy-4'-n-propoxydiphenylsulfone, 4-hydroxy-4'-n-butyroxydiphenylsulfone, and the like, but are not limited thereto. Among them, 4,4'-bisphenolsulfone is preferably used because it is highly effective, inexpensive, and easily available. These developers may be used alone or in combination of two or more.

In the present invention, a phenylbenzyl derivative represented by the general formula (2) is used. General formula (2)
The phenylbenzylsulfone derivative represented by the general formula (1) can be generally obtained by reacting allylsulfinic acid sodium salt with a benzyl chloride derivative. The reaction is performed in water, methanol, ethanol, n-propyl alcohol, is
o-propyl alcohol, acetonitrile, toluene,
In a solvent such as chloroform, diethyl ether, N, N-dimethylacetamide, benzene, chlorobenzene, dichlorobenzene, isopropyl alcohol, diethyl ketone, methyl ethyl ketone, acetone, tetrahydrofuran, etc. at a reaction temperature of 0 to 200 ° C. for several hours to several tens of hours. Will be After the reaction, recrystallization is performed with these solvents, whereby a single compound with high purity and high yield can be obtained. Specific examples of the compound represented by the general formula (2) include phenylbenzylsulfone, 4-methylphenylbenzylsulfone, 3-methylphenylbenzylsulfone, 2-methylphenylbenzylsulfone, and phenyl-sulfone.
4-methylbenzylsulfone, phenyl-3-methylbenzylsulfone, phenyl-2-methylbenzylsulfone, 4-methylphenyl-4'-methylbenzylsulfone, 3-methylphenyl-4'-methylbenzylsulfone, 2-methylphenyl -4'-methylbenzylsulfone, 4-methylphenyl-3'-methylbenzylsulfone, 4-methylphenyl-2'-methylbenzylsulfone, 3-methylphenyl-3'-methylbenzylsulfone, 3-methylphenyl-2 '-Methylbenzylsulfone, 2-methylphenyl-3'-methylbenzylsulfone, 2-methylphenyl-2'-methylbenzylsulfone, 4-methoxyphenylbenzylsulfone, 3-methoxyphenylbenzylsulfone, 2-methoxyphenylbenzylsulfone 4-methoxy-4'-methyl benzyl sulfone, 3-methoxy-4'-methyl benzyl sulfone, 2-methoxy-4'-
Benzyl sulfone, 4-methoxyphenyl-3'-methylbenzylsulfone, 4-methoxyphenyl-2'-methylbenzylsulfone, 3-methoxyphenyl-3'-
Methylbenzylsulfone, 3-methoxyphenyl-2 '
-Methylbenzylsulfone, 2-methoxyphenyl-
3'-methylbenzylsulfone, 2-methoxyphenyl-2'-methylbenzylsulfone and the like.

The basic dye used in the present invention is not particularly limited as long as it is used for general thermosensitive recording paper and pressure-sensitive recording paper. Specific examples include [triphenylmethane-based leuco dye] 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide 3,3-bis (p-dimethylaminophenyl) phthalide, [fluoran Leuco Dye] 3-Diethylamino-6-methylfluoran 3-Diethylamino-6-methyl-7-anilinofluoran 3-Diethylamino-6-methyl-7- (o, p-dimethylanilino) fluoran 3-Diethylamino -6-methyl-7-chlorofluorane 3-diethylamino-6-methyl-7- (m-trifluoromethylanilino) fluoran 3-diethylamino-6-methyl-7- (m-methylanilino) fluoran 3-diethylamino- 6-methyl-7- (o-chloroanilino) fluoran 3-diethylamino- -Methyl-7- (p-chloroanilino) fluoran 3-diethylamino-6-methyl-7-n-octylanilinofluoran 3-diethylamino-6-methyl-7-n-octylaminofluoran 3-diethylamino-6 Methyl-7-benzylanilinofluoran 3-diethylamino-6-methyl-7-dibenzylanilinofluoran 3-diethylamino-6-chloro-7-methylfluoran 3-diethylamino-6-methyl-7-anilino Fluoran 3-diethylamino-6-methyl-7-p-methylanilinofluoran 3-diethylamino-6-methyl-6-ethoxyethyl-7-anilinofluoran 3-diethylamino-7-methylfluoran 3-diethylamino -7-chlorofluorane 3-diethylamino-7- (m-to Trifluoromethylanilino) fluoran 3-diethylamino-7- (o-chloroanilino) fluoran 3-diethylamino-7- (p-chloroanilino) fluoran 3-diethylamino-7- (o-fluoroanilino) fluoran 3-diethylamino-benzo [A] Fluoran 3-diethylamino-benzo [c] fluoran

3-dibutylamino-6-methylfluoran 3-dibutylamino-6-methyl-7-anilinofluoran 3-dibutylamino-6-methyl-7- (o, p-dimethylanilino) fluoran 3 -Dibutylamino-6-methyl-7- (o-chloroanilino) fluoran 3-dibutylamino-6-methyl-7- (p-chloroanilino) fluoran 3-dibutylamino-6-methyl-7- (o-fluoroanilino ) Fluorane 3-dibutylamino-6-methyl-7- (m-trifluoromethylanilino) fluoran 3-dibutylamino-6-methyl-7-chlorofluorane 3-dibutylamino-6-ethoxyethyl-7-ani Linofluoran 3-dibutylamino-6-chloro-7-anilinofluoran 3-dibutylamino-6-meth Tyl-7-p-methylanilinofluoran 3-dibutylamino-7- (o-chloroanilino) fluoran 3-dibutylamino-7- (o-fluoroanilino) fluoran 3-di-n-pentylamino-6 Methyl-7-anilinofluoran 3-di-n-pentylamino-6-methyl-7- (p-
Chloroanilino) fluorane 3-di-n-pentylamino-7- (m-trifluoromethylanilino) fluoran 3-di-n-pentylamino-6-chloro-7-anilinofluoran 3-di-n-pentyl Amino-7- (p-chloroanilino) fluoran 3-pyrrolidino-6-methyl-7-anilinofluoran 3-piperidino-6-methyl-7-anilinofluoran

3- (N-methyl-N-propylamino)
-6-methyl-7-anilinofluoran 3- (N-methyl-N-cyclohexylamino) -6
Methyl-7-anilinofluoran 3- (N-ethyl-N-cyclohexylamino) -6
Methyl-7-anilinofluoran 3- (N-ethyl-N-xylamino) -6-methyl-
7- (p-chloroanilino) fluoran 3- (N-ethyl-p-toluidino) -6-methyl-
7-anilinofluoran 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluoran 3- (N-ethyl-N-azoamylamino) -6-chloro-7-ani Linofluoran 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluoran 3- (N-ethyl-N-isobutylamino) -6-methyl-7-anilinofur Oran 3- (N-ethyl-N-ethoxypropylamino) -6
-Methyl-7-anilinofluoran 3-cyclohexylamino-6-chlorofluoran 2- (4-oxahexyl) -3-dimethylamino-6
-Methyl-7-anilinofluoran 2- (4-oxahexyl) -3-diethylamino-6
-Methyl-7-anilinofluoran 2- (4-oxahexyl) -3-dipropylamino-
6-methyl-7-anilinofluoran 2-methyl-6-p- (p-dimethylaminophenyl)
Aminoanilinofluoran 2-methoxy-6-p- (p-dimethylaminophenyl) aminoanilinofluoran

2-chloro-3-methyl-6-p- (p-
Phenylaminophenyl) aminoanilinofluoran 2-chloro-6-p- (p-dimethylaminophenyl)
Aminoanilinofluoran 2-nitro-6-p- (p-diethylaminophenyl)
Aminoanilinofluoran 2-amino-6-p- (p-diethylaminophenyl)
Aminoanilinofluoran 2-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluoran 2-phenyl-6-methyl-6-p- (p-phenylaminophenyl) aminoanilinofluoran 2- Benzyl-6-p- (p-phenylaminophenyl) aminoanilinofluoran 2-hydroxy-6-p- (p-phenylaminophenyl) aminoanilinofluoran 3-methyl-6-p- (p-dimethyl Aminophenyl)
Aminoanilinofluoran 3-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluoran 3-diethylamino-6-p- (p-dibutylaminophenyl) aminoanilinofluoran 2,4-dimethyl- 6-[(4-dimethylamino) anilino] -fluoran

[Fluorene leuco dye] 3,6,6'-tris (dimethylamino) spiro [fluorene-9,3'-phthalide] 3,6,6'-tris (diethylamino) spiro [fluorene-9,3 '-Phthalide] [divinyl leuco dye] 3,3'-bis- [2- (p-dimethylaminophenyl) -2- (p-methoxyphenyl) ethenyl] -4,
5,6,7-tetrabromophthalide 3,3'-bis- [2- (p-dimethylaminophenyl) -2- (p-methoxyphenyl) ethenyl] -4,
5,6,7-tetrachlorophthalide 3,3-bis- [1,1-bis (4-pyrrolidinophenyl) ethylene-2-yl] -4,5,6,7-tetrabromophthalide 3, 3-bis- [1,1-bis (4-pyrrolidinophenyl) ethylene-2-yl] -4,5,6,7-tetrachlorophthalide [others] 3- (4-diethylamino-2-ethoxyphenyl) )-
3- (1-ethyl-2-methylindol-3-yl)
-4-azaphthalide 3- (4-diethylamino-2-ethoxyphenyl)-
3- (1-octyl-2-methylindol-3-yl) -4-azaphthalide 3- (4-cyclohexylethylamino-2-methoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) ) -4-Azaphthalide 3,3-bis (1-ethyl-2-methylindole-3
-Yl) phthalide 3,6-bis (diethylamino) fluoran-γ-
(3′-nitro) anilinolactam 3,6-bis (diethylamino) fluoran-γ-
(4'-nitro) anilinolactam 1,1-bis- [2 ', 2', 2 ", 2" -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2,
2-dinitrileethane 1,1-bis- [2 ', 2', 2 ", 2" -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2-
β-naphthoylethane 1,1-bis- [2 ′, 2 ′, 2 ″, 2 ″ -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2,
2-diacetylethane bis- [2 ', 2', 2 ", 2" -tetrakis- (p-
Dimethylaminophenyl) -ethenyl] -methylmalonic acid dimethyl ester and the like, and they can be used alone or in combination of two or more as long as the effects of the invention are not impaired.

Further, as conventionally known sensitizers, stearic acid amide, palmitic acid amide, methoxycarbonyl-N-stearic acid benzamide, N-benzoylstearic acid amide, N-eicosanoic acid amide, ethylenebisstearic acid amide, behen Acid amide, methylenebisstearic acid amide, methylenebisstearic acid amide, methylolamide, N-methylolstearic acid amide, dibenzyl terephthalate, dimethyl terephthalate, dioctyl terephthalate, benzyl p-benzyloxybenzoate, 1-hydroxy-2 Phenyl naphthoate, dibenzyl oxalate, di-p-methylbenzyl oxalate, di-p-chlorobenzyl oxalate, 2-naphthylbenzyl ether, p-benzylbiphenyl, 4-
Biphenyl-p-tolyl ether, di (p-methoxyphenoxyethyl) ether, 1,2-di (3-methylphenoxy) ethane, 1,2-di (4-methylphenoxy) ethane, 1,2-di (4 -Methoxyphenoxy) ethane, 1,2-di (4-chlorophenoxy) ethane,
1,2-diphenoxyethane, 1- (4-methoxyphenoxy) -2- (2-methylphenoxy) ethane, p-
Methylthiophenylbenzyl ether, 1,4-di (phenylthio) butane, p-acetotoluidide, p-acetophenethidide, N-acetoacetyl-p-toluidine, di (β-biphenylethoxy) benzene, p-di (vinyloxy) Ethoxy) benzene, 1-isopropylphenyl-2-phenylethane, 1,2-bis (phenoxymethyl) benzene, p-toluenesulfonamide,
It is also possible to use o-toluenesulfonamide, di-p-tolylcarbonate, phenyl-α-naphthylcarbonate, diphenylsulfone and the like in combination without impairing the present invention. In the present invention, as an image stabilizer,
4,4'-butylidene (6-tert-butyl-3-methylphenol), 2,2'-di-tert-butyl-5,5 '
-Dimethyl-4,4'-sulfonyldiphenol, 1,
Adding 1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane and the like Can also.

As the binder used in the present invention, completely saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, butyral-modified polyvinyl alcohol having a polymerization degree of 200 to 1900 are used. , Other modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, ethyl cellulose, cellulose derivatives such as acetyl cellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer, polyvinyl chloride, polyvinyl acetate, poly Acrylamide, polyacrylate, polyvinyl butyral polystyrene and copolymers thereof, polyamide resin, silicone Butter, petroleum resins, terpene resins, ketone resins, coumarone resins. These polymer substances can be used by dissolving them in solvents such as water, alcohols, ketones, esters, and hydrocarbons, and can be used together according to required quality. As the filler used in the present invention, silica, calcium carbonate, kaolin, calcined kaolin, diatom, earth,
Inorganic or organic fillers such as tanks, titanium oxide, aluminum hydroxide and the like. In addition, a release agent such as a fatty acid metal salt, a lubricant such as a wax, a benzophenone-based or triazole-based ultraviolet absorber, a water-resistant agent such as glyoxal, a dispersant, and an antifoaming agent can be used. The amount of the basic dye used in the present invention, the type and amount of other various components are determined according to the required performance and recordability,
Although not particularly limited, usually, 1 to 8 parts of a developer and 1 to 20 parts of a filler are used with respect to 1 part of a dye, and the binder is suitably used in an amount of 10 to 25% based on the total solid content. . The ratio of the developer compound represented by the general formula (1) and the sensitizer compound represented by the general formula (2) is increased with respect to 1 part of the developer, as in the case of this type of heat-sensitive recording material. Sensitizer is about 0.1 to 2 parts. Paper, recycled paper, synthetic paper,
The desired heat-sensitive recording material can be obtained by coating on any support such as a film or plastic. Furthermore, an overcoat layer of a polymer substance containing a filler or the like can be provided on the coloring layer of the thermal paper for the purpose of enhancing the storage stability.
Further, for the purpose of enhancing the storage stability and sensitivity, an undercoat layer containing an organic or inorganic filler can be provided below the thermosensitive coloring layer. The above-mentioned developer, sex dyes and materials to be added as necessary are made into fine particles by a crusher or an emulsifier such as a ball mill, an attritor, a sand grinder or the like to a particle size of several microns or less, and depending on the binder and the purpose. Various additive materials are added to form a coating liquid.

[0018]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The identification of the compound was confirmed by NMR and IR. In the description, parts indicate parts by weight.

[Synthesis of phenyl-3-methylbenzylsulfone] Sodium phenylsulfinate tetrahydrate was placed in a four-necked reaction vessel equipped with a stirrer, a thermometer, and a dropping funnel.
6 g (0.25 mol) and 300 ml of water were added, and the mixture was maintained at 20 ° C. with good stirring. 35.2 g (0.25 mol) of 3-methylbenzyl chloride in THF (100 ml).
The solution was added dropwise, and after completion of the addition, the mixture was stirred at 20 ° C. for 3 hours.
After completion of the reaction, extraction with methylene chloride (300 ml x 2)
Then, the organic layer was washed with water (300 ml × 2) and then dried using sodium sulfate. The sodium sulfate was filtered off and the solvent was removed with a rotary evaporator, whereby white crystals precipitated. When this crystal is recrystallized with ethanol,
Acicular white crystals 47.4 g (yield 77%) of phenyl-3-methylbenzylsulfone was obtained. The melting point was 120 ° C. [Synthesis of 4-methylphenyl-3'-methylbenzylsulfone] 80.6 g (0.25 mol) of sodium p-toluenesulfinate tetrahydrate was placed in a four-necked reaction vessel equipped with a stirrer, a thermometer, and a dropping funnel. And 300 ml of water, and the mixture was kept at 30 ° C. with good stirring. 35.2 g (0.25 mol) of 3-methylbenzyl chloride in THF
(100 ml) solution was added dropwise, and after the addition was completed,
Stirred for hours. After completion of the reaction, extraction with methylene chloride (30
0 ml × 2), and the organic layer was washed with water (300 ml × 2) and then dried using sodium sulfate. The sodium sulfate was filtered off and the solvent was removed with a rotary evaporator, whereby white crystals precipitated. The crystals were recrystallized from ethanol to give acicular white crystals, 4-methylphenyl-3'-.
62.5 g (96% yield) of methylbenzylsulfone was obtained. Melting point was 124.5 ° C. [Synthesis of phenyl-benzylsulfone] According to the synthesis of 4-methylphenylbenzylsulfone, sodium benzenesulfinate tetrahydrate was reacted with benzyl chloride,
The obtained crystals were recrystallized with ethanol to obtain phenylbenzylsulfone as acicular white crystals. Melting point is 14
7.8 ° C.

[Example 1] Liquid A (dye dispersion liquid) 3-Nn-dibutylamino-6-methyl-7-anilinofluoran 2.0 parts 10% aqueous solution of polyvinyl alcohol 4.6 parts Water 2. 5 parts B liquid (developer dispersion liquid) 4,4'-bisphenolsulfone 6.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts water 11.2 parts C liquid (sensitizer dispersion liquid) phenylbenzylsulfone 0 parts 10% aqueous solution of polyvinyl alcohol 12.5 parts Water 7.5 parts Each liquid of the above composition was pulverized with a sand grinder to a particle diameter of 1 micron. Next, the dispersion liquid is mixed at the following ratio to obtain a coating liquid. Liquid A (dye dispersion) 9.1 parts Liquid B (developer dispersion) 36.0 parts Liquid C (sensitizer dispersion) 24.0 parts Kaolin clay (50% dispersion) 12.0 parts The coating liquid is applied on a base paper having a basis weight of 50 g / m ² so as to obtain a coating amount of 6 g / m ^{2 as} a solid content, and is applied at room temperature.
After drying for 4 hours, a calendering treatment was performed to obtain a heat-sensitive recording material.

Example 2 A heat-sensitive recording material was obtained in the same manner as in Example 1 except that phenyl-3-methylbenzylsulfone was used in place of the phenylbenzylsulfone used in the sensitizer dispersion of Example 1. .

Example 3 Instead of phenylbenzylsulfone used in the sensitizer dispersion of Example 1, 4-methylphenyl-3'-methylbenzylsulfone was used.
A heat-sensitive recording material was obtained in the same manner as in Example 1.

Comparative Example 1 A heat-sensitive recording material was obtained in the same manner as in Example 1 except that 2-benzyloxynaphthalene was used instead of phenylbenzylsulfone used in the sensitizer dispersion of Example 1.

Comparative Example 2 A heat-sensitive recording material was obtained in the same manner as in Example 1 except that p-benzylbiphenyl was used in place of phenylbenzylsulfone used in the sensitizer dispersion in the performance test.

[Evaluation method] The following quality performance tests were performed on the heat-sensitive recording materials obtained in the above Examples and Comparative Examples, and the results are shown in Table 1. (1) Dynamic Color Density Printing was performed with an applied energy of 0.38 mj / dot using Okura Electric TH-PMD (a thermal recording paper printing tester equipped with a Kyocera thermal head), and the image density of the recording portion was determined by Macbeth. Densitometer RD-914 (using amber filter)
Was measured. (2) Heat resistance The uncolored thermosensitive recording paper was left for 24 hours under a high-temperature drying condition of 60 ° C., and the ground color density was measured by a Macbeth densitometer. (3) Plasticizer resistance Vinyl chloride wrap (Mitsui Toatsu Hi Wrap KM)
A) was wrapped in a single layer, the thermosensitive recording material recorded in the dynamic color density test was attached thereon, and the vinyl chloride wrap was further wrapped in a triple layer at 40 ° C.
After standing for a period of time, the Macbeth density in the image area and the ground color area was measured.

[0026]

[Table 1]

As is apparent from Table 1, in Examples 1 to 3 of the present invention using the sulfone-based developer represented by the general formula (1) and the phenylbenzylsulfone derivative represented by the general formula (2), An extremely high sensitizing effect is obtained, and the heat resistance of the background and the image storability against a plasticizer are also excellent. on the other hand,
2-Benzyloxynaphthalene and p-benzylbiphenyl, which are known as typical sensitizers, do not exhibit a sensitizing effect on 4,4'-bisphenolsulfone, have low recording density, Image preservability to plasticizers is also poor. Therefore, it can be seen that a thermosensitive recording material having excellent quality performance can be obtained by using a phenylbenzylsulfone derivative represented by the general formula (2) together with a sulfone-based developer, particularly 4,4'-bisphenolsulfone.

[0028]

The heat-sensitive recording material of the present invention is excellent in color-forming sensitivity, and can provide a high-density and clear color-developed image even with minute heat energy. In addition, the stability of the background portion and the image portion is high, which is extremely useful.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kaori Suzuki 955 Komatsuri, Yoshitomi-cho, Yoshitomi-gun, Fukuoka Prefecture Inside the Tomi Fine Chemical Co., Ltd. (72) Inventor Naomi Sumikawa 5-21-1, Oji, Kita-ku, Tokyo Nippon Paper Industries Co., Ltd. F-term (reference) 2H026 AA07 BB01 BB25 BB30 DD02 DD45 DD53

Claims (1)

[Claims] 1. A colorless or pale-colored basic dye on a support, and a color developing agent capable of forming a color upon contact with the dye, represented by the general formula (1): ## STR1 ## [Wherein R ₁ and R ₂ represent a C1 to C8 alkyl group, an alkoxy group, an alkenyl group, an aryl group or a halogen group. A is a hydroxyl group, an alkyl group, an alkoxy group,
It represents an alkenyl group, an aryl group, or an electron withdrawing group.
a, b, and c represent an integer of 0 to 3. And at least one sulfone developer represented by the general formula (2): [In the formula, R ₃ and R ₄ each represent an alkyl group, an alkoxy group, an alkenyl group, or an aryl group of C1 to C4. n and m show the integer of 0-2. ] A heat-sensitive recording material comprising at least one phenylbenzylsulfone derivative represented by the following formula: