JPH09207445A - Thermal recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermal recording sheet having excellent coloring sensitivity by adding a urea (thiourea) derivative in a thermal coloring layer as an organic developer and adding a fixed rate of benzenesulfone anilide derivative in the organic developer as a sensitizer. SOLUTION: On a support body, a thermal coloring layer which contains a colorless or light color basis colorless dye and an organic developer as main components is provided. The thermal coloring layer contains a compound to be expressed by formula I or II as an organic developer, and contains 0.01-2 pts. of benzenesulfone anilide derivative to be expressed by formula III based on 1 pts. of organic developer. (A) represents a hydrogen, a 1-4C alkyl group, R1 -R3 represent a hydrogen atom, a 1-4C alkyl group, (Y) represents a sulfur or oxygen atom, (B) represents a hydrogen, a 1-4C alkyl group, (X) and (Z) represent a 1-6C alkyl group, a 1-6C alkoxy group, and (m) is an integer of 0-2. Thus, a thermal recording sheet having excellent coloring sensitivity can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosensitive recording sheet having excellent color development sensitivity.

[0002]

2. Description of the Related Art In general, a heat-sensitive recording sheet is generally prepared by grinding and dispersing a colorless or light-colored basic colorless dye and an organic developer such as a phenolic substance into fine particles, and then mixing the two with a binder. A coating liquid obtained by adding a filler, a sensitivity improver, a lubricant, and other auxiliaries to a support such as paper, synthetic paper, non-woven fabric, film, plastic, etc. A recorded image is obtained by an instant chemical reaction caused by heating with a hot stamp, a laser beam or the like.

These thermosensitive recording sheets are used for measuring recorders, computer terminal printers, facsimiles, automatic ticket vending machines, ATMs (automated teller machines), HTs.
It has been applied to a wide range of fields such as (handy terminals) and bar code labels, but recently, with the diversification and high performance of these recording devices, the quality requirements for thermal recording sheets have become higher. There is. For example, with the increase in recording speed, it is required that a clear color image with high density can be obtained even with minute heat energy, and on the other hand, a heat-sensitive recording sheet having excellent storage stability such as light resistance, weather resistance and oil resistance is required. Is required.

As a conventional example of a heat-sensitive recording sheet, for example, Japanese Patent Publication No. 43-4160 or Japanese Patent Publication No. 45-1403
However, such a conventional heat-sensitive recording material has, for example, a low thermal response, and cannot provide a sufficient color density at the time of high-speed recording.

As a method for remedying such a defect, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluoran is used as a leuco dye (JP-A-49-109120). Dibutylamino-
Highly sensitive dyes such as using 6-methyl-7-anilinofluorane (JP-A-59-190891) have been developed, and a benzenesulfonanilide derivative is used as a sensitizer (JP-A-58). -211493) has been developed. Further, as color developing agents, substances having good color developability 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane (JP-A-59-106456) and 1,5-bis (4 -Hydroxyphenylthio) -3-oxaheptane
9-116262), 4-hydroxy-4'-isopropoxydiphenyl sulfone (Japanese Patent Publication No. 63-460).
Japanese Patent No. 67) discloses a technique for achieving high speed and high sensitivity.

[0006]

On the other hand, the present inventor has proposed a thermosensitive recording sheet using a novel urea (thiourea) derivative as a developer in Japanese Patent Application No. 6-206714. , Although it supports high energy printing,
In the case of low-energy printing and high-speed printing, sufficient coloring sensitivity was not obtained, and practical application was impossible. An object of the present invention is to provide a thermosensitive recording sheet having excellent color development sensitivity.

[0007]

According to the present invention, a thermosensitive coloring layer contains a urea (thiourea) derivative represented by the following general formula (I) or (II) as an organic developer and is sensitized. By adding 0.01 to 2 parts of the benzenesulfonanilide derivative represented by the following general formula (III) to 1 part of the organic developer represented by the general formula (I) or (II) as an agent, This is a solution to all of the above issues.

[0008]

Embedded image (In the formula, A is hydrogen, a C ₁ -C ₄ alkyl group, C ₁
To C ₄ alkoxy, hydroxy and nitro groups. In the formula, R ₁ , R ₂ and R ₃ are hydrogen atoms, C ₁ to C.
₄ alkyl group, C ₁ -C ₄ alkoxy group, hydroxy group and nitro group. R ₁ and R ₂ may combine with each other to form an aromatic ring. Y is a sulfur atom or an oxygen atom. )

Embedded image (In the formula, B is hydrogen, a C ₁ -C ₄ alkyl group, C ₁
To C ₄ alkoxy, hydroxy and nitro groups. In the formula, R ₁ , R ₂ and R ₃ are hydrogen atoms, C ₁ to C.
₄ alkyl group, C ₁ -C ₄ alkoxy group, hydroxy group and nitro group. R ₁ and R ₂ may combine with each other to form an aromatic ring. Y is a sulfur atom or an oxygen atom. )

[Chemical 6] (However, in the formula, X and Z are C _{1 to} C ₆ alkyl groups, C ₁
An alkoxy group or an electron withdrawing group -C _6. m and n represent the integer of 0-2. )

In the present invention, the general formula (I) or (II)
The urea (thiourea) derivative represented by is more strongly acidic than the phenol compound which is a known color developer, and exhibits a strong color developing ability with respect to a basic colorless dye. The reason is presumed as follows. In the molecule of the urea (thiourea) derivative used in the present invention, there are two sulfonyl groups, carbonyl groups or thiocarbonyl groups, which are strong electron-withdrawing groups, sandwiching the benzene ring. The density is remarkably reduced, and a strong color developing ability is exhibited with respect to a basic colorless dye.

Further, the general formula (II
Since the sensitizer represented by I) has a sulfonamide group in the molecule, when it is heat-melted together with the organic developer represented by the general formula (I) or (II), the nitrogen atom of the organic developer is It is considered that there is an action of further reducing the electron density of and improving the color development sensitivity.

In the present invention, the urea (thiourea) derivative used as the organic developer is exemplified below, but the invention is not limited thereto. Further, the following urea (thiourea) derivatives can be used alone or in combination of two or more as required.

N- (benzenesulfonyl) -p- (phenylureylene) benzamide, N- (4-toluenesulfonyl) -p- (phenylureylene) benzamide, N- (4-ethylphenylsulfonyl) -p- ( Phenylureylene) benzamide, N- (4-n-propylphenylsulfonyl) -p- (phenylureylene) benzamide, N- (4-iso-propylphenylsulfonyl) -p- (phenylureylene) benzamide, N- (T-Butylphenylsulfonyl) -p-
(Phenylureylene) benzamide, N- (4-methoxyphenylsulfonyl) -p- (phenylureylene) benzamide, N- (4-ethoxyphenylsulfonyl) -p- (phenylureylene) benzamide, N
-(4-hydroxyphenylsulfonyl) -p- (phenylureylene) benzamide, N- (2-hydroxyphenylsulfonyl) -p- (phenylureylene) benzamide, N- (4-nitrophenylsulfonyl)-
p- (phenylureylene) benzamide, N- (benzenesulfonyl) -p- (4-tolylureylene) benzamide, N- (4-toluenesulfonyl) -p- (4
-Tolylureylene) benzamide, N- (4-ethylphenylsulfonyl) -p- (4-tolylureylene)
Benzamide, N- (4-iso-propylphenylsulfonyl) -p- (4-tolylureylene) benzamide, N- (n-butylphenylsulfonyl) -p- (4
-Tolylureylene) benzamide, N- (4-methoxyphenylsulfonyl) -p- (4-tolylureylene) benzamide, N- (4-hydroxyphenylsulfonyl) -p- (4-tolylureylene) benzamide, N- (2-hydroxyphenyl) Sulfonyl) -p-
(4-tolylureylene) benzamide, N- (4-nitrophenylsulfonyl) -p- (4-tolylureylene) benzamide, N- (benzenesulfonyl) -p-
(2-naphthylureylene) benzamide, N- (4-
Toluenesulfonyl) -p- (2-naphthylureylene) benzamide, N- (4-iso-propylphenylsulfonyl) -p- (2-naphthylureylene) benzamide, N- (4-methoxyphenylsulfonyl)-
p- (2-naphthylureylene) benzamide, N-
(4-hydroxyphenylsulfonyl) -p- (2-naphthylureylene) benzamide, N- (4-nitrophenylsulfonyl) -p- (2-naphthylureylene)
Benzamide, N- (benzenesulfonyl) -p- (phenylthioureylene) benzamide, N- (4-toluenesulfonyl) -p- (phenylthioureylene) benzamide, N- (4-ethylphenylsulfonyl)-
p- (phenylthioureylene) benzamide, N-
(4-n-propylphenylsulfonyl) -p- (phenylthioureylene) benzamide, N- (4-iso
-Propylphenylsulfonyl) -p- (phenylthioureylene) benzamide, N- (4-methoxyphenylsulfonyl) -p- (phenylthioureylene) benzamide, N- (4-ethoxyphenylsulfonyl)-
p- (phenylthioureylene) benzamide, N-
(4-hydroxyphenylsulfonyl) -p- (phenylthioureylene) benzamide, N- (2-hydroxyphenylsulfonyl) -p- (phenylthioureylene) benzamide, N- (4-nitrophenylsulfonyl) -p- (Phenylthioureylene) benzamide,
N- (benzenesulfonyl) -p- (4-tolylthioureylene) benzamide, N- (4-toluenesulfonyl) -p- (4-tolylthioureylene) benzamide, N- (4-n-propylphenylsulfonyl) ) -P
-(4-Tolylthioureylene) benzamide, N-
(4-methoxyphenylsulfonyl) -p- (4-methylphenylthioureylene) benzamide, N- (4-
(Hydroxyphenylsulfonyl) -p- (4-tolylthioureylene) benzamide, N- (2-hydroxyphenylsulfonyl) -p- (4-methylphenylthioureylene) benzamide, N- (4-nitrophenylsulfonyl)- p- (4-methylphenylthioureylene) benzamide, N- (benzenesulfonyl) -p-
(2-naphthylthioureylene) benzamide, N-
(4-toluenesulfonyl) -p- (2-naphthylthioureylene) benzamide, N- (4-methoxyphenylsulfonyl) -p- (2-naphthylthioureylene)
Benzamide, N- (4-hydroxyphenylsulfonyl) -p- (2-naphthylthioureylene) benzamide, N- (2-hydroxyphenylsulfonyl) -p-
(2-naphthylthioureylene) benzamide, N-
(4-nitrophenylsulfonyl) -p- (2-naphthylthioureylene) benzamide, N- (phenyl)-
N '-(p-benzoylaminosulfonyl) phenylurea, N- (phenyl) -N'-{p- (4-toluoylaminosulfonyl)} phenylurea, N- (phenyl) -N '-{p- ( 2-naphthoylaminosulfonyl) @phenylurea, N- (phenyl) -N '-@ p
-(4-hydroxybenzoylaminosulfonyl)｝ phenylurea, N- (phenyl) -N ′-｛p- (2-
Hydroxybenzoylaminosulfonyl)} phenylurea, N- (phenyl) -N '-{p- (4-methoxybenzoylaminosulfonyl)} phenylurea, N-
(Phenyl) -N '-{p- (4-ethoxybenzoylaminosulfonyl)} phenylurea, N- (phenyl) -N'-{p- (4-n-propoxybenzoylaminosulfonyl)} phenylurea, N- (Phenyl)
-N '-{p- (4-iso-propoxybenzoylaminosulfonyl)} phenylurea, N- (phenyl)
-N '-{p- (4-nitrobenzoylaminosulfonyl)} phenylurea, N- (4-toluyl) -N'-
(P-benzoylaminosulfonyl) phenylurea,
N- (4-toluyl) -N '-{p- (4-toluoylaminosulfonyl)} phenylurea, N- (4-toluyl) -N'-{p- (2-naphthoylaminosulfonyl)} phenyl Urea, N- (3-toluyl) -N'-
(P-benzoylaminosulfonyl) phenylurea,
N- (3-toluyl) -N '-{p- (4-toluoylaminosulfonyl)} phenylurea, N- (3-toluyl) -N'-{p- (3-toluoylaminosulfonyl)} phenyl Urea, N- (3-toluyl) -N'-
{P- (2-toluoylaminosulfonyl)} phenylurea, N- (3-toluyl) -N ′-{p- (2-naphthoylaminosulfonyl)} phenylurea, N-
(4-Toluyl) -N '-{p- (4-hydroxybenzoylaminosulfonyl)} phenylurea, N- (4
-Toluyl) -N '-{p- (2-hydroxybenzoylaminosulfonyl)} phenylurea, N- (4-toluyl) -N'-{p- (4-methoxybenzoylaminosulfonyl)} phenylurea, N- (4-toluyl) -N '-{p- (4-nitrobenzoylaminosulfonyl)} phenylurea, N- (phenyl) -N'-
{P- (4-toluoylaminosulfonyl)} phenylthiourea, N- (phenyl) -N ′-{p- (2-naphthoylaminosulfonyl)} phenylthiourea, N
-(Phenyl) -N '-{p- (4-hydroxybenzoylaminosulfonyl)} phenylthiourea, N-
(Phenyl) -N '-{p- (4-methoxybenzoylaminosulfonyl)} phenylthiourea, N- (phenyl) -N'-{p- (4-nitrobenzoylaminosulfonyl)} phenylthiourea, N- (4 -Toluyl) -N '-(p-benzoylaminosulfonyl) phenylthiourea, N- (4-toluyl) -N'-｛p-
(4-toluoylaminosulfonyl)} phenylthiourea, N- (4-toluyl) -N ′-{p- (3-toluoylaminosulfonyl)} phenylthiourea, N-
(4-toluyl) -N '-{p- (2-naphthoylaminosulfonyl)} phenylthiourea, N- (3-toluyl) -N'-(p-benzoylaminosulfonyl) phenylthiourea, N- (3- Toluyl) -N '-｛p
-(4-toluoylaminosulfonyl)} phenylthiourea, N- (3-toluyl) -N '-{p- (3-toluoylaminosulfonyl)} phenylthiourea, N
-(3-Toluyl) -N '-{p- (2-naphthoylaminosulfonyl)} phenylthiourea, N- (4-toluyl) -N'-{p- (4-hydroxybenzoylaminosulfonyl)} phenylthiourea , N- (4-toluyl) -N '-{p- (4-methoxybenzoylaminosulfonyl)} phenylthiourea, N- (4-toluyl) -N'-{p- (4-nitrobenzoylaminosulfonyl)} Phenylthiourea

Further, in the present invention, as the sensitizer, a compound represented by the general formula
The benzenesulfonanilide derivative represented by (III) is used. In the general formula (III), X and Z are C ₁ to C.
_{And 6 represents} an alkyl group, a C _{1 to} C ₆ alkoxy group, an electron withdrawing group such as a chlorine atom, a nitro group, and a cyano group.
Examples of these specific compounds are shown below, but the invention is not limited thereto.

[0014]

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[0015]

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In the present invention, the content of the sensitizer represented by the general formula (III) is 0.01 part with respect to 1 part of the organic developer represented by the general formula (I) or (II). If less than
When the sensitizing effect is insufficient and the amount is more than 2 parts with respect to 1 part of the organic color developer, sufficient color developing sensitivity cannot be obtained. Therefore, the content of the sensitizer is 0.0 with respect to 1 part of the organic developer.
It is most desirable to contain 1 to 2 parts.

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

<Triphenylmethane type leuco dye> 3,
3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide [also known as crystal violet lactone] <fluorane-based leuco dye (I)> 3-diethylamino-6-methyl-7-anilinofluorane 3- (N-ethyl-p-toluidino) -6-methyl-
7-anilinofluoran 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluoran 3-diethylamino-6-methyl-7- (o, p-dimethylanilino) fluoran 3 -Pyrrolidino-6-methyl-7-anilinofluoran 3-piperidino-6-methyl-7-anilinofluoran 3- (N-cyclohexyl-N-methylamino) -6
Methyl-7-anilinofluoran 3-diethylamino-7- (m-trifluoromethylanilino) fluoran 3-Nn-dibutylamino-6-methyl-7-anilinofluoran 3-Nn-dibutyl Amino-7- (o-chloroanilino) fluoran 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluoran 3-dibutylamino-6-methyl-7- (o, p -Dimethylanilino) fluoran 3- (N-methyl-N-propylamino) -6-methyl-7-anilinofluoran 3-diethylamino-6-chloro-7-anilinofluoran 3-dibutylamino-7- (O-chloroanilino) fluoran 3-diethylamino-7- (o-chloroanilino) fluoran 3-diethylamino-6-methyl-c Lorfluoran 3-diethylamino-6-methyl-fluoran 3-cyclohexylamino-6-chlorofluoran 3-diethylamino-benzo [a] -fluoran 3-n-dipentylamino-6-methyl-7-anilinofluoran 2- ( 4-oxo-hexyl) -3-dimethylamino-
6-methyl-7-anilinofluoran 2- (4-oxo-hexyl) -3-diethylamino-
6-Methyl-7-anilinofluorane 2- (4-oxo-hexyl) -3-dipropylamino-6-methyl-7-anilinofluorane <fluorene-based leuco dye>3,6,6'-tris (Dimethylamino) spiro [fluorene-9,3'-phthalide] 3,6,6'-tris (diethylamino) spiro [fluorene-9,3'-phthalide] <Fluoran-based leuco dye (II)> 2-methyl- 6-p
-(P-Dimethylaminophenyl) aminoanilinofluorane 2-methoxy-6-p- (p-dimethylaminophenyl) aminoanilinofluorane 2-chloro-3-methyl-6-p- (p-phenylamino Phenyl) aminoanilinofluorane 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) aminoanilinofluorane 3-diethylamino-6-p- (p-dibutylaminophenyl) aminoanilinofluorane <Divinyl-based 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> 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

In the present invention, known sensitizers can be used in combination as long as the effects of the present invention are not impaired. Examples of such sensitizers include fatty acid amides such as stearic acid amide and palmitic acid amide, ethylene bisamide, montan wax, polyethylene wax, dibenzyl terephthalate, benzyl p-benzyloxybenzoate, di-
p-tolyl carbonate, p-benzyl biphenyl, phenyl α-naphthyl carbonate, 1,4-diethoxynaphthalene, 1-hydroxy-2-naphthoic acid phenyl ester, 1,2-di- (3-methylphenoxy) ethane, shu Acid di (p-methylbenzyl), β-benzyloxynaphthalene, 4-biphenyl p-tolyl ether, O-xylelin-bis- (phenyl ether), 4
Examples thereof include-(m-methylphenoxymethyl) biphenyl. You may use these sensitizers individually or in mixture of 2 or more types.

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, 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.

The filler used in the present invention is silica,
Calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, tank, titanium oxide, aluminum hydroxide, urea-
Examples include inorganic or organic fillers such as formalin resin and hollow plastic pigments.

In addition, release agents such as fatty acid metal salts, lubricants such as waxes, benzophenone-based or triazole-based UV absorbers, water-proofing agents such as glyoxal, dispersants and defoamers may be used. it can.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The heat-sensitive recording sheet of the present invention comprises a basic colorless dye and the above general formula (I) or (I
As a urea (thiourea) derivative represented by I) and a sensitizer,
The benzenesulfonanilide derivative represented by the general formula (III) is milled and dispersed together with a binder, and a heat-sensitive layer coating liquid is prepared by adding a filler and, if necessary, other additives,
It can be obtained by coating on a support and drying. General formula
The benzenesulfonanilide derivative represented by (III) is an organic developer 1 represented by the general formula (I) or (II).
It is used in a ratio of 0.01 to 2 parts with respect to parts.

The amounts of the organic developer and the basic colorless dye used in the present invention and the types and amounts of other various components are determined according to the required performance and recording suitability, and are not particularly limited. Usually, 0.01 to 2 parts of the sensitizer represented by the general formula (III), 0.1 part of the basic colorless dye to 1 part of the organic developer represented by the general formula (I) or (II). 1-2
Parts and 0.5 to 4 parts of filler are used, and 5 to 25% of the total solid content of the binder is suitable.

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, non-woven fabric, film and plastic. 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 may be provided under the thermosensitive color developing layer for the purpose of enhancing the storage stability and the sensitivity.

The above-mentioned organic color developer, basic colorless dye, sensitizer and, if necessary, materials to be added are pulverizers such as a ball mill, attritor and sand grinder or a suitable emulsifying device or a particle size of 1 micron or less. The mixture is atomized until it becomes, and a binder and various additives according to the purpose are added to obtain a coating liquid.

[0027]

EXAMPLES The present invention will be described below with reference to examples and comparative examples. In addition, in description, a part shows a weight part. [Example 1 (Test Nos. 1 to 32)] Liquid A (dye dispersion liquid) Dye 3-N-n-dibutylamino-6-methyl-7-anilinofluorane 2.0 parts 10% polyvinyl alcohol aqueous solution 4 .6 parts Water 2.5 parts Solution B (developing agent dispersion) Developer (see Table 1 and Table 2) 6.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts Water 11.2 parts Solution C (increased Sensitizer Dispersion) Sensitizer (see Tables 1 and 2) 4.0 parts 10% aqueous polyvinyl alcohol solution 12.5 parts water 7.5 parts Each solution of the above composition is sand grinder to a particle size of 1 micron. Ground Then, the dispersion liquids are mixed in the following proportions to prepare a coating liquid. Solution A (dye dispersion) 9.1 parts Solution B (developing agent dispersion) 36.0 parts Solution C (sensitizer dispersion) 24.0 parts Kaolin clay (50% dispersion) 12.0 parts Above 5.0g of coating liquid on one side of 50g / m ² base paper
/ M ² was applied and dried, and this sheet was treated with a super calender so as to have a smoothness of 400 to 500 seconds to obtain a heat-sensitive recording paper.

Comparative Example 1 (Test Nos. 33 to 35) Liquid A (dye dispersion) Dye 3-Nn-dibutylamino-6-methyl-7-anilinofluorane 2.0 parts 10% polyvinyl Aqueous alcohol solution 4.6 parts Water 2.5 parts Liquid D (developing agent dispersion) Developer (see Table 5) 6.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts Water 11.2 parts The above composition Each liquid of (3) was ground to a particle size of 1 micron with a sand grinder. Then, the dispersion liquids are mixed in the following proportions to prepare a coating liquid. Solution A (dye dispersion) 9.1 parts Solution D (developing agent dispersion) 36.0 parts Kaolin clay (50% dispersion) 12.0 parts Each of the above coating solutions on one side of 50 g / m ² base paper Apply amount to 5.0
The coated sheet was dried so as to be g / m ² , and this sheet was treated with a super calender so that the smoothness was 400 to 500 seconds to obtain a thermal recording paper.

Comparative Example 2 (Test Nos. 36 to 37) Liquid A (dye dispersion) Dye 3-Nn-dibutylamino-6-methyl-7-anilinofluorane 2.0 parts 10% polyvinyl Aqueous alcohol solution 4.6 parts Water 2.5 parts D solution (developing agent dispersion) Developer (see Table 5) 6.0 parts 10% polyvinyl alcohol aqueous solution 18.8 parts Water 11.2 parts E solution (increased Sensitizer dispersion) P-benzylbiphenyl (abbreviation PBB) 4.0 parts 10% aqueous polyvinyl alcohol solution 12.5 parts water 7.5 parts Each solution of the above composition was ground to a particle size of 1 micron with a sand grinder. . Then, the dispersion liquids are mixed in the following proportions to prepare a coating liquid. Solution A (dye dispersion) 9.1 parts Solution D (developer dispersion) 36.0 parts Solution E (sensitizer dispersion) 24.0 parts Kaolin clay (50% dispersion) 12.0 parts Apply each coating solution to one side of 50g / m ² base paper at 5.0
The coated sheet was dried so as to be g / m ² , and this sheet was treated with a super calender so that the smoothness was 400 to 500 seconds to obtain a thermal recording paper.

Comparative Example 3 (Test Nos. 38 to 42) Liquid A (dye dispersion liquid) Dye 3-Nn-dibutylamino-6-methyl-7-anilinofluorane 2.0 parts 10% polyvinyl Aqueous alcohol solution 4.6 parts Water 2.5 parts F solution (developing agent dispersion) Developer (see Table 5) 6.0 parts 10% polyvinyl alcohol aqueous solution 18.8 parts Water 11.2 parts C solution (increased Sensitizer dispersion) Sensitizer (see Table 5) 4.0 parts 10% aqueous polyvinyl alcohol solution 12.5 parts water 7.5 parts Each solution of the above composition was ground to a particle size of 1 micron with a sand grinder. . Then, the dispersion liquids are mixed in the following proportions to prepare a coating liquid. Solution A (dye dispersion) 9.1 parts Solution F (developing agent dispersion) 36.0 parts Solution C (sensitizer dispersion) 24.0 parts Kaolin clay (50% dispersion) 12.0 parts Above 5.0g of coating liquid on one side of 50g / m ² base paper
/ M ² was applied and dried, and this sheet was treated with a super calender so as to have a smoothness of 400 to 500 seconds to obtain a heat-sensitive recording paper.

The thermal recording papers obtained in the above Examples and Comparative Examples were subjected to the following quality performance tests, and the results are shown in Table 3.
The results are shown in Tables 4 and 6. Note (1) Dynamic color density; TH-PMD manufactured by Okura Electric Co., Ltd.
(Thermal recording paper printing tester, Kyocera, equipped with thermal head), applied energy 0.30 mj / dot
And image densities recorded at 0.38 mj / dot using Macbeth densitometer (RD-914, amber filter used)
It was measured at.

[0032]

[Table 1]

[Table 2]

[0033]

[Table 3]

[Table 4]

[0034]

[Table 5]

[Table 6]

As is clear from Table 3, Table 4 and Table 6,
An organic developer represented by the general formula (I) or (II),
In Example 1 of the present invention using the sensitizer represented by the general formula (III), an extremely high sensitizing effect was obtained. on the other hand,
Comparative Example 1 in which the sensitizer represented by the general formula (III) is not used, P- which is known to have a sensitizing effect on a known representative phenolic developer (for example, bisphenol A) Comparative Example 2 using benzylbiphenyl and a conventional representative phenolic color developer are used in the general formula of the present invention.
In Comparative Example 3 in which the sensitizer represented by (III) was combined,
The sensitizing effect is extremely poor and the recording density is low. Therefore, it is understood that the excellent effect can be obtained only when the compound of the general formula (I) or (II) and the compound of the general formula (III) are used at the same time.

[0036]

INDUSTRIAL APPLICABILITY In the present invention, urea (thiourea) represented by the general formula (I) or (II) is used as the organic developer.
By using a derivative and a benzenesulfonanilide derivative represented by the above general formula (III) as a sensitizer, it is possible to obtain a clear high density image with excellent thermal response and high speed and high density recording. To be

Claims (1)

[Claims] 1. A thermosensitive recording sheet 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 the thermosensitive coloring layer is an organic developer. Containing a compound represented by the following general formula (I) or (II) as a sensitizer and having the following general formula (III)
The benzenesulfonanilide derivative represented by
A heat-sensitive recording sheet containing 0.01 to 2 parts with respect to 1 part of the organic developer represented by (I) or (II). Embedded image (In the formula, A is hydrogen, a C ₁ -C ₄ alkyl group, C ₁
To C ₄ alkoxy, hydroxy and nitro groups. In the formula, R ₁ , R ₂ and R ₃ are hydrogen atoms, C ₁ to C.
₄ alkyl group, C ₁ -C ₄ alkoxy group, hydroxy group and nitro group. R ₁ and R ₂ may combine with each other to form an aromatic ring. Y is a sulfur atom or an oxygen atom. ) (In the formula, B is hydrogen, a C ₁ -C ₄ alkyl group, C ₁
To C ₄ alkoxy, hydroxy and nitro groups. In the formula, R ₁ , R ₂ and R ₃ are hydrogen atoms, C ₁ to C.
₄ alkyl group, C ₁ -C ₄ alkoxy group, hydroxy group and nitro group. R ₁ and R ₂ may combine with each other to form an aromatic ring. Y is a sulfur atom or an oxygen atom. ) (However, in the formula, X and Z are C _{1 to} C ₆ alkyl groups, C ₁
An alkoxy group or an electron withdrawing group -C _6. m and n represent the integer of 0-2. )