JPH11286173A - Thermal recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the fineness of a recording image part and the fastness of a coloring agent by containing a molecular level admixture of o- toluenesulfonamide and p-toluenesulfonamide in a thermal coloring layer in a thermal recording body in which a thermal recording layer containing as main components a basic achromatic dye and an organic developing agent is provided on a carrier. SOLUTION: The thermal recording body is provided on a carrier with a thermal coloring layer containing main components a basic chromatic dye and an organic developing agent, in which a molecular level admixture of o- toluenesulfonamide and p-toluenesulfonamide in a thermal coloring layer. This avoids a powdering phenomenon being prone to occur at the time of using an intensifier in the imaging part, thus enhancing the stability in the recording part under high humidity. A blending weight ratio of o-toluensulfonamide to p-toluenesulfonamide used is made 35:65-45:55, and a molecular level admixture of o-toluenesulfonamide and p-toluenesulfonamide is contained at a rate of 0.01-2 pts. to an organic developer of 1 pts.

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 medium having excellent color sensitivity.

[0002]

2. Description of the Related Art In general, a heat-sensitive recording sheet is usually prepared by grinding and dispersing a colorless or pale-colored dye precursor (a basic colorless dye) and a developer such as a phenolic compound into fine particles. Is mixed, a binder, a filler, a sensitivity enhancer, a coating solution obtained by adding a lubricant and other auxiliaries, paper, synthetic paper, film, coated on a support such as plastic, A color is formed by an instantaneous chemical reaction caused by heating of a thermal head, a hot stamp, a hot pen, a laser beam or the like, and a recorded image is obtained. These thermosensitive recording materials are applied to a wide range of fields such as measurement recorders, computer terminal printers, facsimile machines, vending machines, barcode labels, etc. As a result, the required quality of the heat-sensitive recording medium has become higher. For example, with the increase in recording speed, it is required to obtain a high-density and clear color image even with minute heat energy.

As a method for satisfying this requirement, it has been proposed to use an additive material (sensitizer) having an appropriate melting point and solubility in combination with a basic colorless dye and a color developer. For example, p-benzylbiphenyl (melting point 86-87 ° C, JP-A-60-82382), benzyl p-benzyloxybenzoate (melting point 117-119 ° C, JP-A-57-2)
01691), benzyl naphthyl ether (melting point 101 ° C., JP-A-58-87094), or 4
-Biphenyl-p-tolyl ether (melting point 95-97)
C., JP-A-63-272852) are used as suitable sensitizers. In addition, for the purpose of further improving the sensitivity and expanding the selectivity of usable materials, a plurality of heat-fusible substances (including sensitizers) are added to the basic colorless dye and developer.
It has been proposed to use a solid solution or a eutectic of the above (JP-A-1-188289).

When a sensitizer comprising one or more compounds as described above is used, the sensitizer is first melted when heated, and is dissolved by dissolving a basic colorless dye and a developer. Both are mixed at the molecular level to induce a color development reaction, and a recorded image is obtained. Therefore, thermal recording becomes possible even at low energy, and high-speed recording becomes possible.

However, when these sensitizers are used, there is a problem that heat resistance is remarkably deteriorated and background fog is caused depending on the combination of a basic colorless dye and a developer. In addition, the addition of the sensitizer frequently causes a problem that the recorded image is whitened over time (hereinafter, referred to as a powder blowing phenomenon). In particular, this powder blowing phenomenon tends to be promoted in a high heat environment or a high humidity environment.

One method of improving the heat resistance while using a sensitizer is to select a compound having a relatively high melting point as the sensitizer, but in this case, the sensitizing effect is generally low. Such a sensitizer is disclosed in
Some examples are found in the aromatic sulfonamide compounds described in JP 38186B. Particularly, o-toluenesulfonamide and p-toluenesulfonamide, which are industrially useful from the viewpoint of raw material availability and use, have an appropriate sensitizing effect despite their relatively high melting points. However, as described above, there was a problem with the powder blowing phenomenon in the recorded image area, and it was difficult to say that this was a practical sensitizer.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat-sensitive recording material which has greatly improved the color-forming sensitivity and has improved the powder blowing phenomenon of a recorded image area, which has conventionally been a problem caused by the addition of a sensitizer. To provide.

[0008]

SUMMARY OF THE INVENTION The present invention provides a method for manufacturing a semiconductor device comprising the steps of:
In a heat-sensitive recording medium provided with a heat-sensitive coloring layer containing a colorless or light-colored basic colorless dye and an organic color developer as main components, o-toluenesulfonamide and p
-The above problem has been solved at once by containing a molecular level mixture with toluenesulfonamide.

The molecular level mixture of o-toluenesulfonamide and p-toluenesulfonamide referred to in the present invention may be a mixture of both dispersions or a mixture of both powders at the time of dispersion. It is obtained by a method different from mixing at the particle level, and means that o-toluenesulfonamide and p-toluenesulfonamide are mixed at the molecular level. That is,
The molecular level mixture of o-toluenesulfonamide and p-toluenesulfonamide in the present invention is obtained by a method of hot-melting both to obtain a mixture, a method of dissolving the mixture in a solvent and then precipitating the mixture to obtain a mixture, or Is prepared by, for example, a method in which a mixture is precipitated as it is after the synthesis.

[0010] The melting point of o-toluenesulfonamide used in the present invention is about 154 to 156 ° C, and the melting point of p-toluenesulfonamide is about 136 to 138 ° C.
The melting point of the mixture at the molecular level is lowered by the eutectic point effect, and an excellent sensitizing effect is obtained. The melting temperature varies depending on the mixing ratio of the two, especially when the mixing weight ratio of o-toluenesulfonamide and p-toluenesulfonamide is in the range of 35:65 to 45:55, the melting temperature of these molecular level mixtures Is about 100 ° C ~ 11
The temperature drops to near 0 ° C., and an extremely high sensitizing effect is obtained.

The content of the molecular mixture of o-toluenesulfonamide and p-toluenesulfonamide in the thermosensitive coloring layer can be appropriately adjusted within a range where a desired effect can be obtained. 0.0 for 1 part
When added in a proportion of 1 to 2 parts, a thermosensitive recording medium having an excellent balance of quality performance is obtained and is effective. When less than 0.01 part is added to 1 part of the organic developer, the sensitizing effect is relatively difficult to be exhibited. On the other hand, when 2 parts or more are added, the color density is lowered due to the decrease in the content ratio of the color-forming material. Some decrease and adhesion of scum are observed.

The heat-sensitive recording material of the present invention is characterized in that the blowing phenomenon of the recorded image area does not occur even though the heat-sensitive coloring layer contains a sensitizer. The reason for this has not been clearly elucidated, but is presumed as follows.

In the case where o-toluenesulfonamide and p-toluenesulfonamide are used alone, in addition to a general known sensitizer, a basic colorless dye, an organic developer, and a sensitizer are used. In a recorded image area composed of a hot melt formed by an observer, the effect of a sensitizer on the relationship where there is a strong interaction (charge transfer complex) such as a color-forming reaction between a basic colorless dye and an organic developer. The force is considered very small. Therefore, it is considered that after solidification, the sensitizer is more stable when the sensitizer alone is present, so that recrystallization proceeds, and as a result, a powder blowing phenomenon is caused. Also,
It is also considered that the sensitizer generally used has a low molecular weight and many of which have sublimability, which is one of the causes of the powder blowing phenomenon. Furthermore, since the heat-melted portion heated rapidly by the thermal head with the thermal head in msec units instantly returns to room temperature, there is a part of the unmelted sensitizer, or the heat-melted portion is not adjacent to the heat-melted portion. It is considered that the presence of the melted sensitizer causes these unmelted sensitizers to become nuclei to further promote recrystallization.

[0014] In response to such a powder blowing phenomenon, the molecular mixture of o-toluenesulfonamide and p-toluenesulfonamide used in the present invention is characterized in that o-toluenesulfonamide and p-toluenesulfonamide are substituted. It is structurally very similar except for the positional relationship of the groups,
In addition, it is considered that recrystallization is suppressed and the compound does not have sublimation property by the binary molecular mixture in which a sulfamoyl group (or aminosulfonyl group; -NH ₂ SO ₂ group) is present in the structure. Probably, such a structural feature causes a strong interaction between the two-component molecules, and the two-component molecule mixture is in an extremely stable state. If solidification after instantaneous thermal melting does not occur, recrystallization or sublimation does not occur. Conceivable.

Further, o-toluenesulfonamide and p-toluenesulfonamide, which are mixed at the molecular level, are particles that can be obtained by simply mixing both dispersions or mixing and dispersing both powders during dispersion. For those that are mixed at the level, recrystallization does not always occur because there is no single substance o-toluenesulfonamide or p-toluenesulfonamide, that is, since there can be no substance serving as a crystal nucleus. It is considered that no powder blowing phenomenon was observed due to no occurrence of the powder blowing.

Further, a heat-sensitive recording medium using an organic developer having a high melting point of, for example, 150 to 160 ° C. or more, particularly an organic developer having a high melting point of more than 200 ° C., has a heat resistance of a background portion. Although it is useful because it is good, in the case of a thermal recording medium using these organic developers and conventional sensitizers at the same time, the heat-melted part heated by a thermal head etc. solidifies rapidly with a basic colorless dye. The sensitizer is easily separated, and the powder blowing phenomenon easily occurs. In contrast, a molecular level mixture of o-toluenesulfonamide and p-toluenesulfonamide is a high-melting point developer such as a urea-based compound, thiourea-based compound, or aminobenzenesulfonamide having a high melting point or decomposition point. Even when it is contained in a heat-sensitive recording material using a derivative or the like, it exhibits an excellent sensitizing effect without causing a powder blowing phenomenon for the reasons described above, and is very useful.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a method for preparing o-toluenesulfonamide and p-toluenesulfonamide which are mixed at the molecular level is as follows. A method of obtaining a molecular mixture of both by cooling, solidifying and cooling, dissolving both in a solvent (good solvent), adding them to a large amount of a solvent (poor solvent) that does not dissolve, precipitating, and then pulverizing the molecular mixture. Or as an example of a synthesis method, without separating a mixture of o-toluenesulfonyl chloride and p-toluene sunyl chloride, which is produced by changing the reaction temperature from toluene and chlorosulfuric acid at an arbitrary ratio by adjusting the reaction temperature or the like. To obtain a molecular mixture in a desired ratio.

The organic developer used in the present invention includes the following bisphenol A, 4-hydroxybenzoic acid ester, 4-hydroxyphthalic acid diester, phthalic acid monoester, and bis- (hydroxyphenyl) sulfide , 4-hydroxyphenylarylsulfones, 4-hydroxyphenylarylsulfonates,
1,3-di [2- (hydroxyphenyl) -2-propyl] -benzenes, 4-hydroxybenzoyloxybenzoic acid esters, bisphenolsulfones, urea derivatives, thiourea derivatives, aminobenzenesulfonamide derivatives However, the present invention is not limited to these. Further, an organic developer may be used alone or in combination of two or more. Hereinafter, specific examples of the organic color developer will be described.

<Bisphenol A>4,4'-isopropylidene diphenol (also known as bisphenol A) 4,4'-cyclohexylidene diphenol p, p '-(1-methyl-normalhexylidene) diphenol 1, 7-di (hydroxyphenylthio) -3,5-dioxaheptane <4-hydroxybenzoates> Benzyl 4-hydroxybenzoate Ethyl 4-hydroxybenzoate Propyl 4-hydroxybenzoate 4-Isopropyl benzoate 4 -Butyl hydroxybenzoate 4-Isobutyl 4-hydroxybenzoate Methylbenzyl 4-hydroxybenzoate <Diesters of 4-hydroxyphthalic acid> Dimethyl 4-hydroxyphthalate 4-Diisopropyl 4-hydroxyphthalate 4-Dibenzyl 4-hydroxyphthalate 4-hydro Shifutaru acid dihexyl

<Monoesters of phthalic acid> Monobenzyl phthalate Monocyclohexyl phthalate Monophenyl phthalate Monomethyl phenyl phthalate Monoethyl phenyl phthalate Monopropyl benzyl phthalate Monohalogen benzyl phthalate Phthalic acid Monoethoxybenzyl ester <Bis- (hydroxyphenyl) sulfides> Bis- (4-hydroxy-3-tert-butyl-6-
Methylphenyl) sulfide bis- (4-hydroxy-2,5-dimethylphenyl)
Sulfide bis- (4-hydroxy-2-methyl-5-ethylphenyl) sulfide bis- (4-hydroxy-2-methyl-5-isopropylphenyl) sulfide bis- (4-hydroxy-2,3-dimethylphenyl)
Sulfide bis- (4-hydroxy-2,5-dimethylphenyl)
Sulfide bis- (4-hydroxy-2,5-diisopropylphenyl) sulfide bis- (4-hydroxy-2,3,6-trimethylphenyl) sulfide bis- (2,4,5-trihydroxyphenyl) sulfide bis- ( 4-hydroxy-2-cyclohexyl-5-methylphenyl) sulfide bis- (2,3,4-trihydroxyphenyl) sulfide bis- (4,5-dihydroxy-2-tert-butylphenyl) sulfide bis- (4- Hydroxy-2,5-diphenylphenyl) sulfide bis- (4-hydroxy-2-tert-octyl-5)
-Methylphenyl) sulfide

<4-hydroxyphenylarylsulfones>4-hydroxy-4'-isopropoxydiphenylsulfone4-hydroxy-4'-n-butyloxydiphenylsulfone4-hydroxy-4'-n-propoxydiphenylsulfone<melting point 150-152 ° C><4-hydroxyphenylarylsulfonates> 4-hydroxyphenylbenzenesulfonate 4-hydroxyphenyl-p-tolylsulfonate 4-hydroxyphenylmethylenesulfonate 4-hydroxyphenyl-p-chlorobenzenesulfonate 4-hydroxyphenyl-p-tert-butylbenzenesulfonate 4-hydroxyphenyl-p-isopropoxybenzenesulfonate 4-hydroxyphenyl-1'-naphthalenesulfonate 4- Hydroxyphenyl-2'-naphthalene sulfonate

<1,3-di [2- (hydroxyphenyl) -2-propyl] benzenes> 1,3-di [2- (4-hydroxyphenyl) -2-propyl] benzene 1,3-di [ 2- (4-hydroxy-3-alkylphenyl) -2-propyl] benzene 1,3-di [2- (2,4-dihydroxyphenyl)-
2-propyl] benzene 1,3-di [2- (2-hydroxy-5-methylphenyl) -2-propyl] benzene <resorcinols> 1,3-dihydroxy-6 (α, α-dimethylbenzyl) -benzene <4-Hydroxybenzoyloxybenzoate> Benzyl 4-hydroxybenzoyloxybenzoate Methyl 4-hydroxybenzoyloxybenzoate Ethyl 4-hydroxybenzoyloxybenzoate Propyl 4-hydroxybenzoyloxybenzoate Butyl 4-hydroxybenzoyloxybenzoate Isopropyl 4-hydroxybenzoyloxybenzoate tert-butyl 4-hydroxybenzoyloxybenzoate hexyl 4-hydroxybenzoyloxybenzoate octyl 4-hydroxybenzoyloxybenzoate 4-h Roxybenzoyloxy nonyl 4-hydroxybenzoyloxybenzoate cyclohexyl 4-hydroxybenzoyloxybenzoate β-phenethyl 4-hydroxybenzoyloxybenzoate phenyl 4-hydroxybenzoyloxybenzoate α-naphthyl 4-hydroxybenzoyloxybenzoate β -Naphthyl sec-butyl 4-hydroxybenzoyloxybenzoate

<Bisphenolsulfones (I)> bis- (3-1-butyl-4-hydroxy-6-methylphenyl) sulfone bis- (3-ethyl-4-hydroxyphenyl) sulfone bis- (3-propyl-) 4-hydroxyphenyl) sulfone bis- (3-methyl-4-hydroxyphenyl) sulfone bis- (2-isopropyl-4-hydroxyphenyl)
Sulfone bis- (2-ethyl-4-hydroxyphenyl) sulfone bis- (3-chloro-4-hydroxyphenyl) sulfone bis- (2,3-dimethyl-4-hydroxyphenyl)
Sulfone bis- (2,5-dimethyl-4-hydroxyphenyl)
Sulfone bis- (3-methoxy-4-hydroxyphenyl) sulfone 4-hydroxyphenyl-2'-ethyl-4'-hydroxyphenylsulfone 4-hydroxyphenyl-2'-isopropyl-4'-
Hydroxyphenylsulfone 4-hydroxyphenyl-3'-isopropyl-4'-
Hydroxyphenylsulfone 4-hydroxyphenyl-3'-secbutyl-4'-
Hydroxyphenylsulfone 3-chloro-4-hydroxyphenyl-3'-isopropyl-4'-hydroxyphenylsulfone 2-hydroxy-5-t-butylphenyl-4'-hydroxyphenylsulfone 2-hydroxy-5-t-aminophenyl -4'-hydroxyphenylsulfone 2-hydroxy-5-t-isopropylphenyl-4 '
-Hydroxyphenylsulfone 2-hydroxy-5-t-octylphenyl-4'-hydroxyphenylsulfone 2-hydroxy-5-t-butylphenyl-3'-chloro-4'-hydroxyphenylsulfone 2-hydroxy-5-t -Butylphenyl-3'-methyl-4'-hydroxyphenylsulfone 2-hydroxy-5-tert-butylphenyl-3'-isopropyl-4'-hydroxyphenylsulfone 2-hydroxy-5-tert-butylphenyl-2 '-Methyl-4'-hydroxyphenylsulfone<Bisphenolsulfones(II)>4,4'-Sulfonyldiphenol<Melting point 240 to 25
0 ° C.> 2,4′-sulfonyl diphenol <melting point 185 ° C. or more> 3,3′-dichloro-4,4′-sulfonyl diphenol 3,3′-dibromo-4,4′-sulfonyl diphenol 3,3 ', 5,5'-Tetrabromo-4,4'-sulfonyldiphenol 3,3'-diamino-4,4'-sulfonyldiphenol

<Aminobenzenesulfonamide derivatives (I)> 2-Sulfamoylcarbanilide <Decomposition point: about 181 ° C.> 2-Sulfamoyl-3′-ethylcarbanilide 2-sulfamoyl-4′-chlorocarbani Lido 2-sulfamoyl-3 ', 4'-dichlorocarbanilide 2-sulfamoyl-4'-bromocarbanilide 2-sulfamoyl-4'-methoxycarbanilide 2-sulfamoyl-3'-nitrocarbanilide 2- Sulfamoylthiocarbanilide 2-sulfamoyl-4'-methoxythiocarbanilide 3-sulfamoylcarbanilide <decomposition point about 208 ° C>3-sulfamoyl-4'-methylcarbanilide 3-sulfamoyl-3 ' -Chlorocarbanilide 3-sulfamoyl-3 ', 4'-dichlorocarbanilide < Decomposition point about 242 ° C>3-sulfamoyl-4'-bromocarbanilide3-sulfamoyl-2'-fluorocarbanilide3-sulfamoyl-4'-methoxycarbanilide3-sulfamoyl-4'-nitrocarbanilide 1,5-dichloro-3-sulfamoylcarbanilide 3-sulfamoyl-4-chloro-3'-chlorocarbanilide 3-sulfamoylthiocarbanilide 3-sulfamoyl-4'-ethylthiocarbanilide 3 -Sulfamoyl-4'-chlorothiocarbanilide 3-sulfamoyl-3 ', 4'-dichlorothiocarbanilide 3-sulfamoyl-3'-bromothiocarbanilide 3-sulfamoyl-4'-fluorothiocarbanilide 3-sulfamoyl-3'-methoxythiocarbanilide 3-sulfamoyl- '-Nitrothiocarbanilide 4-chloro-3-sulfamoylthiocarbanilide 3-sulfamoyl-5-bromo-3'-chlorothiocarbanilide 4-sulfamoylcarbanilide <decomposition point about 236 ° C>4-sulfamoyl-4'-methylcarbanilide<decomposition point about 249 ° C>4-sulfamoyl-4'-chlorocarbanilide<decomposition point about 256 ° C>4-sulfamoyl-2'-chlorocarbanilide<decomposition point About 236 ° C.> 4-sulfamoyl-2 ′, 5′-dichlorocarbanilide <decomposition point about 264 ° C.> 4-sulfamoyl-3 ′, 4′-dichlorocarbanilide <decomposition point about 264 ° C.> 4-sulfamoyl -4'-fluorocarbanilide 4-sulfamoyl-4'-methoxycarbanilide <decomposition point about 258 ° C> 2,6-dichloro-4-sulfur Moil carbanilide 4-sulfamoyl-4'-nitro carbanilide 1,5-dichloro-3-sul Famo dolphins Le Bani Lido 4- sulfamoyl Lucio carbanilide <decomposition point about 198
C>4-sulfamoyl-4'-methylthiocarbanilide2,5,6-trichloro-4-sulfamoyl-3'-
Chlorothiocarbanilide 4-sulfamoyl-4'-ethoxythiocarbanilide

<Aminobenzenesulfonamide derivatives (II)> 1- (2-sulfamoylphenyl) -3-benzylurea 1- (2-sulfamoylphenyl) -3- (4-methylbenzyl) urea 1 -(2-sulfamoylphenyl) -3- (α, α-
Dimethylbenzyl) urea 1- (2-sulfamoylphenyl) -3- (3-isopropenyl-α, α-dimethylbenzyl) urea 1- (2-sulfamoylphenyl) -3- (n-propyl) Urea 1- (2-sulfamoylphenyl) -3-isopropylurea 1- (2-sulfamoylphenyl) -3-cyclohexylurea 1- (2-sulfamoylphenyl) -3- (2-propenyl) urea 1- (2-sulfamoylphenyl) -3- (α-naphthyl) urea 1- (2-sulfamoylphenyl) -3-benzylthiourea 1- (2-sulfamoylphenyl) -3- (3- Isopropenyl-α, α-dimethylbenzyl) thiourea 1- (2-sulfamoylphenyl-3-methyl) -3
-(N-propyl) urea 1- (2-sulfamoylphenyl) -3-benzenesulfonylurea 1- (2-sulfamoylphenyl) -3- (p-toluenesulfonyl) urea 1- (2-sulfamoyl) Moylphenyl) -3- (p-toluenesulfonyl) thiourea 1- (2-sulfamoylphenyl) -3- (m-methoxybenzenesulfonyl) urea 1- (3-sulfamoylphenyl) -3-benzylurea 1- (3-sulfamoylphenyl) -3- (4-chlorobenzyl) urea 1- (3-sulfamoylphenyl) -3- (α, α-
Dimethylbenzyl) urea 1- (3-sulfamoylphenyl) -3- (3-isopropenyl-α, α-dimethylbenzyl) urea <decomposition point about 199 ° C.> 1- (3-sulfamoylphenyl)- 3- (3-Isopropenyl-α, α-dimethylbenzyl) urea 1- (2,4,6-trichloro-3-sulfamoylphenyl) -3- (n-propyl) urea 1- (3-sulfur Famoylphenyl) -3-isopropylurea 1- (3-sulfamoylphenyl) -3-cyclohexylurea 1- (3-sulfamoylphenyl) -3- (1-propenyl) urea 1- (3-sulfa Moylphenyl) -3- (β-naphthyl) urea 1- (3-sulfamoylphenyl) -3- (3-isopropenyl-α, α-dimethylbenzyl) thiourea 1- (3-sulfamoi Phenyl) -3-cyclohexylthiourea 1- (3-sulfamoylphenyl) -3- (α-naphthyl) thiourea 1- (3-sulfamoylphenyl) -3-benzenesulfonylurea 1- (3-sulfur Famoylphenyl) -3- (o-toluenesulfonyl) urea 1- (3-sulfamoylphenyl) -3- (p-toluenesulfonyl) urea 1- (3-sulfamoylphenyl) -3- (p- Toluenesulfonyl) thiourea 1- (3-sulfamoylphenyl) -3- (m-toluenesulfonyl) urea 1- (3-sulfamoylphenyl) -3- (p-methoxybenzenesulfonyl) urea 1- (3 -Sulfamoylphenyl) -3- (m-methoxybenzenesulfonyl) urea 1- (3-sulfamoylphenyl) -3- (m-methoxybe Sensulfonyl) thiourea 1- (3-sulfamoylphenyl) -3-methanesulfonylurea 1- (3-sulfamoylphenyl) -3-cyclohexanesulfonylurea 1- (3-sulfamoylphenyl) -3- (1-propene) sulfonylurea 1- (3-sulfamoylphenyl) -3- (α-naphthalene) sulfonylurea 1- (4-sulfamoylphenyl) -3-benzylurea <decomposition point about 250 ° C.> 1 -(4-sulfamoylphenyl) -3- (3-bromobenzyl) urea 1- (4-sulfamoylphenyl) -3- (α, α-
Dimethylbenzyl) urea 1- (4-sulfamoylphenyl) -3- (3-isopropenyl-α, α-dimethylbenzyl) urea 1- (4-sulfamoylphenyl) -3- (n-propyl) Urea <decomposition point about 213 ° C.> 1- (2,6-dichloro-4-sulfamoylphenyl) -3-chloromethylurea 1- (4-sulfamoylphenyl) -3- (4-methylcyclohexyl) urea 1- (4-sulfamoylphenyl) -3-ethynyl urea 1- (4-sulfamoylphenyl) -3- (α-naphthyl) urea <decomposition point about 252 ° C.> 1- (4-sulfamoylphenyl) ) -3-Benzylthiourea <decomposition point about 193 ° C> 1- (4-sulfamoylphenyl) -3- (3-isopropenyl-α, α-dimethylbenzyl) urea <decomposition point about 209 ° C> 1- (4-sulfamoylphenyl) -3-cyclohexylthiourea <decomposition point about 203 ° C> 1- (4-sulfamoylphenyl) -3-benzenesulfonylurea <decomposition point about 212 ° C> 1- (4-sulfur Famoylphenyl) -3- (2-propenyl) urea 1- (4-sulfamoylphenyl) -3- (o-toluenesulfonyl) urea 1- (4-sulfamoylphenyl) -3- (p-toluene Sulfonyl) urea <decomposition point about 205 ° C.> 1- (4-sulfamoylphenyl) -3- (p-toluenesulfonyl) thiourea 1- (4-sulfamoylphenyl) -3- (m-toluenesulfonyl) Urea 1- (4-sulfamoylphenyl) -3- (p-methoxybenzenesulfonyl) urea 1- (4-sulfamoylphenyl) -3- (p-methoxybe Zensuruhoniru) thiourea 1- (4-sulfamoylphenyl)-3-(m-methoxybenzenesulfonyl) urea

<Others> p-tert-butylphenol 2,4-dihydroxybenzophenone novolak-type phenol resin 4-hydroxyacetophenone p-phenylphenol benzyl-4-hydroxyphenylacetate p-benzylphenol 4,4'-bis (p-toluene Sulfonylaminocarbonylamino) diphenylmethane 4,4'-bis (p-toluenesulfonylaminocarbonylamino) diphenyl ether 3,3'-bis (p-toluenesulfonylaminocarbonylamino) diphenylsulfone 1,3-diphenylurea <melting point 240 ° C> 1,3-diphenylthiourea <melting point 151 ° C>

The basic colorless dye used in the present invention is not particularly limited, but is preferably a triphenylmethane type, a fluoran type, a fluorene type, a divinyl type or the like, and specific examples thereof will be shown below. These dyes can be used alone or in combination of two or more.

<Triphenylmethane leuco dye> 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide [also known as crystal violet lactone] 3,3-bis (p-dimethylaminophenyl) phthalide Also known as malachite green lactone]

<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-chlorofluoran 3-diethylamino-6-methyl-7- (m-trifluoromethylanilino) fluoran 3-diethylamino-6-methyl-7- (o-chloroanilino) Fluoran 3-diethylamino-6-methyl-7- (p-chloroanilino) fluoran 3-diethylamino-6-methyl-7- (o-fluoroanilino) fluoran 3-diethylamino-6-methyl-7-n-octylanilino Fluoran 3-diethylamino-6-methyl-7-n-octylua Minofluoran 3-diethylamino-6-methyl-7-benzylanilinofluoran 3-diethylamino-6-methyl-7-dibenzylanilinofluoran 3-diethylamino-6-chloro-7-methylfluoran 3-diethylamino-6 -Chloro-7-anilinofluorane 3-diethylamino-6-chloro-7-p-methylanilinofluoran 3-diethylamino-6-ethoxyethyl-7-anilinofluoran 3-diethylamino-7-methylfluoran 3-diethylamino-7- (chloroanilino) fluoran 3-diethylamino-7- (m-trifluoromethylanilino) fluoran 3-diethylamino-7- (o-chloroanilino) fluoran 3-diethylamino-7- (p-chloroanilino) fluoran 3 -Diethylamino-7- ( -Fluoroanilino) fluoran 3-diethylamino-benzo [a] fluoran 3-diethylamino-benzo [c] fluoran 3-dibutylamino-6-methyl-fluoran 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) fluoran 3-dibutylamino-6-methyl-7- (m-trifluoromethylanilino) fluoran 3-dibutylamino-6 -Methyl-chlorofluoran 3-dibutylamino-6-ethoxyethyl- 7-anilinofluoran 3-dibutylamino-6-chloro-7-anilinofluoran 3-dibutylamino-6-methyl-7-p-methylanilinofluoran 3-dibutylamino-7- (o-chloroanilino ) Fluoran 3-dibutylamino-7- (o-fluoroanilino) fluoran 3-n-dipentylamino-6-methyl-7-anilinofluoran 3-n-dipentylamino-6-methyl-7- (p- Chloroanilino) fluoran 3-n-dipentylamino-6-chloro-7-anilinofluoran 3-n-dipentylamino-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-isoamylamino) -6-chloro-7-anilino Fluoran 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluoran 3- (N-ethyl-N-isobutylamino) -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)
Aminoanilinofluorane 3-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluoran 3-diethylamino-6-p- (p-dibutylaminophenyl) aminoanilinofluoran

<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- (4-methoxyphenyl) -1-
(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

As the binder used in the present invention, completely saponified polyvinyl alcohol having a degree of polymerization of 200 to 1900, partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, butyral-modified polyvinyl alcohol Alcohol, other modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer and ethyl cellulose, cellulose derivatives such as acetyl cellulose, polyvinyl chloride, polyvinyl acetate,
Examples thereof include polyacrylamide, polyacrylate, polyvinyl butyral polystyrene, and copolymers thereof, polyamide resin, silicone resin, petroleum resin, terpene resin, ketone resin, and cumarone resin. These macromolecules are water, alcohol, ketone,
In addition to dissolving in solvents such as esters and hydrocarbons,
It is used in a state of being emulsified or dispersed in a paste form in water or another medium, and may be used in combination depending on required quality.

In the present invention, a known stabilizer metal salt of p-nitrobenzoic acid (Ca, Zn) or metal salt of monobenzyl phthalate (Ca, Zn) is used as long as the effects of the present invention are not impaired. It is also possible to add. Examples of fillers used in the present invention include inorganic or organic fillers such as silica, calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, tanks, titanium oxide, and aluminum hydroxide. In addition, release agents such as fatty acid metal salts, lubricants such as waxes, benzophenone-based and triazole-based ultraviolet absorbers, water-proofing agents such as glyoxal, dispersants, and defoamers can be used.

The amounts of the sensitizer, the organic developer and the basic colorless dye, and the types and amounts of other various components used in the present invention are determined according to the required performance and recording suitability, and are not particularly limited. Although not present, 1 to 8 parts of a developer and 1 to 16 parts of a sensitizer of the present invention are used for 1 part of a basic colorless dye.
Parts and 1 to 20 parts of filler, and the binder is suitably used in an amount of 10 to 25% based on the total solid content. These materials are pulverized to a particle size of several microns or less by a pulverizer such as a ball mill, an attritor, a sand grinder or an appropriate emulsifying device, and a binder and various additive materials are added according to the purpose to form a coating liquid. .

The desired heat-sensitive recording sheet can be obtained by applying the coating solution having the above composition to any support such as paper, synthetic paper, plastic film, and non-woven fabric. Further, an overcoat layer of a filler-containing polymer substance or the like can be provided on the thermosensitive coloring layer for the purpose of enhancing the storage stability. Further, an undercoat layer containing an organic filler or an inorganic filler can be provided below the thermosensitive coloring layer for the purpose of enhancing the storage stability and sensitivity.

[0036]

The present invention will be described below with reference to examples.
In addition, in description, a part shows a weight part. [Sensitizer Production Example 1] A mixture having the following composition was heated,
It was melted uniformly. This is cooled to room temperature and solidified,
After that, by pulverizing, o- having a weight ratio of 40:60 is obtained.
A molecular level mixture of toluenesulfonamide and p-toluenesulfonamide was obtained (S-1). The melting start temperature of this molecular level mixture was 103 ° C. or higher. 1.6 parts of o-toluenesulfonamide 2.4 parts of p-toluenesulfonamide

[Sensitizer Preparation Example 2] A weight ratio of 25: 7 was prepared in the same manner as in the sensitizer preparation example 1 except that the sensitizer was prepared from the following composition.
A molecular level mixture of o-toluenesulfonamide and p-toluenesulfonamide, which was 5, was obtained (S-2).
The melting start temperature of this molecular level mixture was 130 ° C. or higher. o-toluenesulfonamide 1.0 part p-toluenesulfonamide 3.0 parts

[Sensitizer Preparation Example 3] A weight ratio of 35: 6 was prepared in the same manner as in the sensitizer preparation example 1 except that the sensitizer was prepared from the following composition.
Thus, a molecular level mixture of o-toluenesulfonamide and p-toluenesulfonamide was obtained (S-3).
The melting onset temperature of this molecular level mixture was 120 ° C. or higher. o-toluenesulfonamide 1.4 parts p-toluenesulfonamide 2.6 parts

[Sensitizer Preparation Example 4] A weight ratio of 45: 5 was prepared in the same manner as in the sensitizer Preparation Example 1 except that the sensitizer was prepared from the following composition.
Thus, a molecular level mixture of o-toluenesulfonamide and p-toluenesulfonamide was obtained (S-4).
The melting start temperature of this molecular level mixture was 110 ° C. or higher. o-toluenesulfonamide 1.8 parts p-toluenesulfonamide 2.2 parts

[Sensitizer Preparation Example 5] A weight ratio of 75: 2 was obtained in the same manner as in the sensitizer preparation example 1 except that the sensitizer was prepared from the following composition.
Thus, a molecular level mixture of o-toluenesulfonamide and p-toluenesulfonamide 5 was obtained (S-5).
The melting start temperature of this molecular level mixture was 130 ° C. or higher. o-toluenesulfonamide 3.0 parts p-toluenesulfonamide 1.0 parts

Hereinafter, Examples and Comparative Examples for producing a thermosensitive recording medium will be described. [Examples 1 to 10] 3-Dibutylamino-6-methyl-7-anilinofluorane was used as a color developer and a basic colorless dye shown below, and S- of Preparation Example 1 was used as a sensitizer.
This is an example using No. 1. Developer used in each Example (Example 1) 4,4'-isopropylidene diphenol (Example 2) 4-hydroxy-4'-isopropylidene diphenyl sulfone (Example 3) 4-hydroxy-4 ' -N-propoxydiphenyl sulfone (Example 4) 4,4'-sulfonyl diphenol (Example 5) 2,4'-sulfonyl diphenol (Example 6) 1,3-diphenylthiourea (Example 7) 1 (Example 8) 2-Sulfamoylcarbanilide (Example 9) 3-Sulfamoylcarbanilide (Example 10) 4-Sulfamoylcarbanilide A solution (developing agent) Dispersion solution) Developer 6.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts Water 11.2 parts Liquid B (dye dispersion liquid) 3-dibutylamino-6-methyl-7-anilinofluoran 2.0 parts 10% aqueous solution of polyvinyl alcohol 4.6 parts Water 2.6 parts Liquid C (sensitizer dispersion) Sensitizer (S-1) 4.0 parts 10% aqueous solution of polyvinyl alcohol 9.2 parts Water 5 .2 parts Each liquid of the above composition was ground with a sand grinder to an average particle size of 1 micron. Subsequently, the dispersion liquid was mixed at the following ratio to obtain a coating liquid. Liquid A 36.0 parts Liquid B 9.2 parts Liquid C 18.4 parts Kaolin clay (50% dispersion) 12.0 parts Amount of each of the above coating liquids applied to one side of 50 g / m ² base paper 6.0
g / m ² and dried, and the sheet was treated with a super calender to have a smoothness of 500 to 600 seconds to produce a thermosensitive recording medium.

Examples 11 to 14 Thermosensitive recording media were prepared in the same manner as in Example 2 except that the following sensitizers (see Production Examples 2 to 5) were used instead of S-1. Sensitizer used in each example (Example 11) S-2 (Example 12) S-3 (Example 13) S-4 (Example 14) S-5

Examples 15 to 18 Heat-sensitive recording media were prepared in the same manner as in Example 9 except that the following sensitizers (see Production Examples 2 to 5) were used instead of S-1. Sensitizer used in each example (Example 15) S-2 (Example 16) S-3 (Example 17) S-4 (Example 18) S-5

Examples 19 to 24 In the same manner as in Example 2 except that the liquid C (sensitizer dispersion) prepared using the above S-1 was changed to the following compounding ratio. A coating solution was prepared, and a thermal recording medium was prepared using the coating solution. Mixing ratio of solution C (sensitizer dispersion) in coating liquid in each example (Example 19) 0.05 part (Example 20) 0.5 part (Example 21) 4.6 parts (Example 22) ) 36.8 parts (Example 23) 55.2 parts (Example 24) 69.0 parts

Examples 25 to 30 In the same manner as in Example 9 except that the liquid C (sensitizer dispersion) prepared using S-1 was changed to the following compounding ratio. A coating solution was prepared, and a thermal recording medium was prepared using the coating solution. Mixing ratio of liquid C (sensitizer dispersion) in coating liquid in each example (Example 25) 0.05 part (Example 26) 0.5 part (Example 27) 4.6 parts (Example 28) 36.8 parts (Example 29) 55.2 parts (Example 30) 69.0 parts

Example 31 The basic colorless dye used in the above-mentioned liquid B (dye dispersion) was converted from 3-dibutylamino-6-methyl-7-anilinofluoran to 3- (N-ethyl-
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that (N-isoamylamino) -6-methyl-7-anilinofluoran was used.

Example 32 The basic colorless dye used in the above-mentioned liquid B (dye dispersion) was converted from 3-dibutylamino-6-methyl-7-anilinofluoran to 3- (N-ethyl-
A heat-sensitive recording material was prepared in the same manner as in Example 2 except that the composition was changed to (N-isoamylamino) -6-methyl-7-anilinofluoran.

Example 33 The basic colorless dye used in the above-mentioned liquid B (dye dispersion) was converted from 3-dibutylamino-6-methyl-7-anilinofluoran to 3-diethylamino-7- (m-triene). A heat-sensitive recording material was prepared in the same manner as in Example 5, except that the composition was changed to (fluoromethylanilino) fluorane.

Example 34 The basic colorless dye used in the above-mentioned liquid B (dye dispersion liquid) was converted from 3-dibutylamino-6-methyl-7-anilinofluoran to 3-diethylamino-6-methyl-7-. A heat-sensitive recording material was produced in the same manner as in Example 3 except that anilinofluorane was used.

Example 35 The basic colorless dye used in the above-mentioned liquid B (dye dispersion) was converted from 3-dibutylamino-6-methyl-7-anilinofluoran to 3-diethylamino-6-methyl-7-. A heat-sensitive recording material was produced in the same manner as in Example 10 except that anilinofluorane was used.

[Comparative Examples 1 to 10] Comparative examples using a developer shown below and 3-dibutylamino-6-methyl-7-anilinofluoran as a basic colorless dye (without sensitizer) ). Examples 1 to 10 except that the sensitizer was omitted
In the same manner as in the above, a thermosensitive recording medium was obtained. Developer used in each comparative example (Comparative Example 1) 4,4'-isopropylidene diphenol (Comparative Example 2) 4-hydroxy-4'-isopropylidene diphenyl sulfone (Comparative Example 3) 4-hydroxy-4 ' -N-propoxydiphenyl sulfone (Comparative Example 4) 4,4'-sulfonyldiphenol (Comparative Example 5) 2,4'-sulfonyldiphenol (Comparative Example 6) 1,3-diphenylthiourea (Comparative Example 7) 1 Comparative Example 8 2-Sulfamoylcarbanilide (Comparative Example 9) 3-Sulfamoylcarbanilide (Comparative Example 10) 4-Sulfamoylcarbanilide

[Comparative Examples 11 to 15] In the liquid C (sensitizer dispersion) prepared using the above S-1, the following sensitizers were used except that the following sensitizers were used instead of S-1. A coating liquid was prepared in the same manner as in Example 2, and a thermosensitive recording medium was prepared using the coating liquid. Sensitizer used in each Comparative Example (Comparative Example 11) o-Toluenesulfonamide (Comparative Example 12) p-Toluenesulfonamide (Comparative Example 13) Benzyl p-benzyloxybenzoate (Comparative Example 14) p-benzylbiphenyl (Comparative Example 15) Phenyl p-toluenesulfonate

[Comparative Example 16] Solution C (sensitizer dispersion) was
A coating solution was prepared in the same manner as in Example 2 except that the following C1 solution was used, and a thermosensitive recording medium was prepared using the same.
This is an example in which two kinds of sensitizers are dispersed at the same time. C1 solution (sensitizer mixed simultaneous dispersion) 1.6 parts of o-toluenesulfonamide 2.4 parts of p-toluenesulfonamide 9.2 parts of a 10% aqueous solution of polyvinyl alcohol 9.2 parts of water 5.2 parts

[Comparative Example 17] Solution C (sensitizer dispersion) was
A coating liquid was prepared in the same manner as in Example 2 except that the C2 liquid was changed to use a molecular level mixture (T-1) having the following composition and prepared in the same manner as in Preparation Example 1 of the sensitizer. Was used to produce a thermosensitive recording medium. This is an example in which a molecular level mixture other than the present invention is used as a sensitizer. T-1 sensitizer charge composition Phenyl p-toluenesulfonate 2.0 parts Dibenzoylmethane 2.0 parts C2 liquid (T-1 sensitizer dispersion liquid) T-1 4.0 parts 10% aqueous solution of polyvinyl alcohol 9 .2 parts water 5.2 parts

[Comparative Example 18] Solution C (sensitizer dispersion) was
A coating liquid was prepared in the same manner as in Example 2 except that the C3 liquid was changed to a liquid mixture (T-2) having the following composition and prepared in the same manner as in Preparation Example 1 of the sensitizer. Was used to produce a thermosensitive recording medium. This is an example in which a molecular level mixture other than the present invention is used as a sensitizer. T-2 sensitizer charge composition Phenyl p-toluenesulfonate 2.0 parts 1-Hydroxy-2-naphthoate 2.0 parts C3 solution (T-2 sensitizer dispersion) 4.0 parts T-2 10% aqueous solution of polyvinyl alcohol 9.2 parts Water 5.2 parts

[Comparative Example 19] Liquid C (sensitizer dispersion liquid)
A coating liquid was prepared in the same manner as in Example 2 except that the C4 liquid was changed to use a molecular level mixture (T-3) having the following composition and prepared in the same manner as in Preparation Example 1 of the sensitizer. Was used to produce a thermosensitive recording medium. This is an example in which a molecular level mixture other than the present invention is used. T-3 sensitizer charge composition 1.6 parts of benzyl p-benzyloxybenzoate 2.4 parts of p-benzylbiphenyl C4 liquid (T-3 sensitizer dispersion) 4.0 parts of T-3 10% polyvinyl alcohol Aqueous solution 9.2 parts Water 5.2 parts

[Comparative Examples 20 to 21] In the solution C (sensitizer dispersion) prepared using the above-mentioned S-1, the following sensitizers were used except that the following sensitizers were changed from S-1. A coating solution was prepared in the same manner as in Example 9 and used to prepare a thermosensitive recording medium. Sensitizer used in each comparative example (Comparative Example 20) o-toluenesulfonamide (Comparative Example 21) p-toluenesulfonamide

Comparative Example 22 Liquid C (sensitizer dispersion) was
A coating liquid was prepared in the same manner as in Example 9 except that the liquid C1 shown in Comparative Example 16 was changed, and a thermosensitive recording medium was prepared using the coating liquid. This is an example in which a sensitizer mixed and co-dispersed product is used.

Comparative Example 23 Liquid C (sensitizer dispersion) was
A coating solution was prepared in the same manner as in Example 9 except that the liquid C2 was changed to the liquid C2 using the molecular level mixture (T-1) shown in Comparative Example 17, and a thermosensitive recording medium was prepared using the coating liquid. This is an example in which a molecular level mixture other than the present invention is used as a sensitizer.

Comparative Example 24 Liquid C (sensitizer dispersion) was
A coating solution was prepared in the same manner as in Example 9 except that the C4 solution was changed to the C4 solution using the molecular level mixture (T-3) shown in Comparative Example 19, and a thermosensitive recording medium was prepared using the same. It is an example using a molecular level mixture other than the present invention.

[Comparative Example 25] In liquid C (sensitizer dispersion) prepared using S-1, except that the sensitizer was changed from S-1 to o-toluenesulfonamide and used. A coating liquid was prepared in the same manner as in Example 1, and a thermosensitive recording medium was prepared using the coating liquid.

[Comparative Example 26] In the liquid C (sensitizer dispersion liquid) prepared by using S-1, except that the sensitizer was changed from S-1 to o-toluenesulfonamide and used. A coating liquid was prepared in the same manner as in Example 3, and a thermosensitive recording medium was prepared using the coating liquid.

[Comparative Example 27] In the solution C (sensitizer dispersion) prepared by using S-1, except that the sensitizer was changed from S-1 to p-toluenesulfonamide and used. A coating liquid was prepared in the same manner as in Example 7, and a thermosensitive recording medium was prepared using the coating liquid.

[Comparative Example 28] In the liquid C (sensitizer dispersion) prepared using the above-mentioned S-1, the sensitizer was S-1
A coating solution was prepared in the same manner as in Example 10 except that p-toluenesulfonamide was used instead of p-toluenesulfonamide.

With respect to the heat-sensitive recording materials obtained in the above Examples and Comparative Examples, the following quality performance tests were performed. The results are shown in Tables 1 to 4. [Thermal Recording Test (Dynamic Color Density)] Applied energy 0.30 and 0.38 mj / dot using TH-PMD (thermal recording paper printing tester, Kyocera thermal head) manufactured by Okura Electric Co., Ltd. Then, a thermal recording was performed on the produced thermal recording medium (the same thermal recording was performed under the same conditions).
The recording density of the recording unit was measured using a Macbeth densitometer (RD-914,
The measurement was carried out under the same conditions using an amber filter. Examples 1 to 35 in which the compound of the present invention was used as a developer
With regard to the heat-sensitive recording material of Example 1, a sufficient recording density was obtained by a printer. By optimizing the mixing ratio and the addition amount of o-toluenesulfonamide and p-toluenesulfonamide mixed at the molecular level, extremely high recording sensitivity was sometimes obtained (Examples 1, 2, 3, and 11). , 12, 13, 1
4, 20, 21, 22, 23, 31, 32). Also, 2
An excellent sensitizing effect of the molecular level mixture of the present invention was also observed for a developer having a melting point or decomposition point of 00 ° C. or higher (Examples 8, 9, 16, 17, 28, and 29).

[0066]

Table 1 Recording density of heat-sensitive recording materials of Examples 1 to 18

[0067]

Table 2 Recording density of heat-sensitive recording materials of Examples 19 to 35

[0068]

Table 3 Recording density of heat-sensitive recording media of Comparative Examples 1 to 18

[0069]

Table 4 Recording density of heat-sensitive recording media of Comparative Examples 19 to 28

[Evaluation Test of Powder Blowing Phenomenon] The applied energy of 0.38 mj / dot was measured using the above-described thermal recording paper printing tester.
Then, the thermosensitive recording medium was subjected to thermosensitive recording, and the thermosensitive recording part was left under the conditions of (1) one week after the recording, (2) 24 hours at 40 ° C., and (3) 60 °, and thereafter, visually determined Was done. (1) Even when the recording part was left for one week, no powder blowing phenomenon was observed in the thermal recording medium of the example using the molecular level mixture of the present invention. On the other hand, except for the heat-sensitive recording materials of Comparative Examples 1 to 10 not using a sensitizer, all of the recording portion surfaces of the heat-sensitive recording materials of Comparative Examples 11 to 28 using a sensitizer other than the present invention were used. Powder blowing phenomenon was observed. (2) Even when the recording part was left at 40 ° C. for 24 hours, no powder blowing phenomenon was observed in the thermal recording medium of the example using the molecular level mixture of the present invention. On the other hand, except for the heat-sensitive recording materials of Comparative Examples 1 to 10 not using a sensitizer, all of the recording portion surfaces of the heat-sensitive recording materials of Comparative Examples 11 to 28 using a sensitizer other than the present invention were used. Powder blowing phenomenon was observed. Among them, except for Comparative Example 6, the substances causing the powder blowing phenomenon could be wiped off. In particular, Comparative Examples 15, 17, 20, 21, 23, 24, 27, 2
In the heat-sensitive recording medium of No. 8, the powder blowing portion was 0.3 mm below the original recording density.
One or more drops. (3) Even when the recording part was left under the condition of 60 ° C., the powder recording phenomenon was not recognized at all in the heat-sensitive recording medium of the example using the molecular level mixture of the present invention. On the other hand, except for the heat-sensitive recording materials of Comparative Examples 1 to 10 not using a sensitizer, all of the recording portion surfaces of the heat-sensitive recording materials of Comparative Examples 11 to 28 using a sensitizer other than the present invention were used. The powder blowing phenomenon was observed, and the powder blowing part showed a drop of 0.1 or more from the original recording density.

[0071]

The heat-sensitive recording material according to the present invention does not cause any powder blowing phenomenon in the image area, which tends to occur when a sensitizer is used, and has the following excellent effects. (1) The recorded image area is stable even at high temperature or high humidity. (2) Even if a developer having a high melting point and a high decomposition point is used, powder blowing does not occur. (3) It is useful as a sensitizer for a thermosensitive recording medium in which background coloring does not occur even at high temperatures.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Chuichi Fukuchi 1-30-6 Kamiochiai, Shinjuku-ku, Tokyo Japan Paper Manufacturing Co., Ltd. (72) Inventor Naomi Sumikawa 1-30-6 Kamiochiai, Shinjuku-ku, Tokyo No. Japan Paper Manufacturing Co., Ltd.

Claims (3)

[Claims] 1. A thermosensitive recording medium comprising a support and a thermosensitive coloring layer containing a colorless or light-colored basic colorless dye and an organic developer as main components, wherein o-
A heat-sensitive recording material comprising a molecular level mixture of toluenesulfonamide and p-toluenesulfonamide. 2. The thermosensitive recording according to claim 1, wherein the mixing weight ratio of o-toluenesulfonamide and p-toluenesulfonamide is 35:65 to 45:55 in the thermosensitive coloring layer. body. 3. In the thermosensitive coloring layer, a molecular level mixture of o-toluenesulfonamide and p-toluenesulfonamide is added in an amount of 0.01 to 2 parts per 1 part of the organic developer.
3. The composition of claim 1 or 2, wherein
The thermosensitive recording medium as described.