JPH0999645A - Thermal recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance color forming sensitivity to a large extent by adding an aminobenzenesulfonamide derivative to the thermal color forming layer of a thermal recording material as an org. coupler and adding a sulfone compd. thereto as a sensitizer in a specific ratio. SOLUTION: In a thermal recording material wherein a thermal color forming layer containing a basic leuco dye and an org. coupler as main components is provided on a support, an aminobenzenesulfoneamide derivative represented by formula I is added to the thermal color forming layer as an org. couple. Further, at least one kind of a compd. represented by formula II or III is added as a sensitizer in an amt. of 0.01-2 pts. per one part of the coupler represented by the formula. In the formula I, X is an oxygen atom or a sulfur atom, Y is a 1-6C lower alkyl group or an electron withdrawing group and R is a phenyl group or an aralkyl group. In the formula II, R<1> and R<2> are a halogen atom or a 1-6C alkyl group and, in the formula III, R<3> and R<4> are a hydrogen atom or a 1-6C alkoxy group.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In general, a thermosensitive recording medium is usually prepared by grinding and dispersing a colorless or pale-colored basic colorless dye and an organic developer such as a phenolic compound into fine particles, and then mixing the two. A coating obtained by adding a binder, a filler, a sensitivity enhancer, a lubricant and other auxiliaries to a support such as paper, synthetic paper, film, plastic, etc. Color is formed by an instantaneous chemical reaction caused by heating with a hot stamp, hot pen, laser light or the like, and a recorded image is obtained. Thermal recording media are facsimile machines, computer terminal printers, automatic ticket vending machines, measuring records
Widely used for Dar etc. In recent years, high-speed printing and high-speed image formation have become possible along with the diversification of recording apparatuses and the advancement of performance, and higher quality is required for the recording sensitivity of a thermosensitive recording medium.

As a method for satisfying this requirement, it has been proposed to use a dye and a developer together with a sensitizer. For example, when the color developer consists of a phenolic compound represented by bisphenol A, p-benzylbiphenyl (JP-A-60-82382) and benzyl p-benzyloxybenzoate (JP-A-57-201691) No.), benzyl naphthyl ether (JP-A-58-87094) and the like have been used as suitable sensitizers. When using a sensitizer,
When heated, the sensitizer first melts, and when it melts the dye and developer, they both mix at the molecular level and induce a color development reaction. Is important.

On the other hand, the inventors of the present invention filed Japanese Patent Application No. 6-1000.
No. 82, Japanese Patent Application No. 6-168516, Japanese Patent Application No. 6-195568, etc., an aminobenzenesulfonamide derivative having an aminosulfonyl group (—SO ₂ NH ₂ ) is used as a developer. However, when the applied energy is high, the color development sensitivity is good, but when the applied energy is low or when printing is performed at a high speed, sufficient color density cannot be obtained. It was insufficient for practical use in equipment that requires them.

[0005]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a thermosensitive recording material using an aminobenzenesulfonamide derivative as a color developer, in which the coloring sensitivity is greatly improved.

[0006]

The inventors of the present invention have conducted extensive studies to develop a thermosensitive recording medium having the above-mentioned properties, and as a result, have used an aminobenzenesulfonamide derivative as a color developer, which has a sulfonyl group. By using an aromatic compound having (—SO ₂ —) or an aminosulfonyl group (—SO ₂ NH—) as a sensitizer, the recording sensitivity was significantly improved and the present invention was completed. .
That is, the present invention provides a thermosensitive recording layer comprising, on a support, a thermosensitive coloring layer containing a colorless or pale-colored basic colorless dye and an organic developing agent as main components. A compound containing an aminobenzenesulfonamide derivative represented by the following general formula (I) as an agent and a compound represented by the following general formula (II) or (III) as a sensitizer is represented by the following general formula (I). 0.01 for 1 part developer
The present invention relates to a thermosensitive recording medium characterized by containing at least one kind in a ratio of 2 parts.

[0007]

Embedded image (In the formula, X represents an oxygen atom or a sulfur atom, and Y represents 1 carbon atom.
~ 6 represents a lower alkyl group or an electron-withdrawing group, and l represents an integer of 0-4. R represents an unsubstituted or substituted phenyl group, an aralkyl group, a lower alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a lower alkenyl group having 2 to 6 carbon atoms, or a naphthyl group. )

Embedded image (In the formula, R ₁ and R ₂ are a halogen atom or a carbon number of 1 to
6 represents an alkyl group, and m and n represent an integer of 0-2. )

[Chemical 6] (In the formula, R ₃ and R ₄ represent a hydrogen atom, an alkoxy group having 1 to 6 carbon atoms or an allyloxy group.)

In the present invention, at least one aminobenzenesulfonamide derivative represented by the general formula (I) is used as an organic developer. In the general formula (I), X is an oxygen atom or a sulfur atom, and Y may be a substituent that does not deteriorate the color developing ability. Such a substituent has 1 to 6 carbon atoms such as a methyl group and an ethyl group. And lower electron groups, electron-withdrawing groups such as chlorine atom, nitro group and methoxy group. R represents a hydrocarbon group, specifically, a phenyl group, an aralkyl group, a lower alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a lower alkenyl having 2 to 6 carbon atoms. Group or naphthyl group. In addition, R may be substituted with a substituent that does not inhibit color development, and examples of the substituent include a lower alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group or a chlorine atom, a nitro group, a methoxy group and the like. Examples thereof include electron-withdrawing groups. Specific examples of the compound represented by the general formula (I) include (I-1) to (I-72) shown below, and the present invention is not limited thereto.
From the viewpoint of availability of raw materials and ease of synthesis (I-10)
Is preferably used. Further, in the present invention, for the purpose of improving sensitivity, it is possible to use a conventionally known developer together with about 0.01 to 0.9 part by weight per 1 part of the compound of the general formula (I).

[0009]

[Chemical 7]

Embedded image

[0010]

Embedded image

Embedded image

[0011]

Embedded image

[Chemical 12]

[0012]

Embedded image

Embedded image

In the present invention, at least one compound represented by the general formula (II) or (III) is used as a sensitizer. In the general formula (II), R ₁ and R ₂ may be substituents which do not inhibit the sensitizing effect, and examples of such substituents include a halogen atom or an alkyl group having 1 to 6 carbon atoms. . Specific examples of the compound represented by the general formula (II) are shown below (II-1) to (II-
14), but not limited thereto. Above all, (II-1) or (II-2) is preferably used since the effect when used with the above-mentioned color developer (I-10) is good.

[0014]

[Chemical 15]

Embedded image

Further, in the general formula (III), R ₃ and R _{4 are}
Is a hydrogen atom or a substituent which does not inhibit the sensitizing effect, and examples of such a substituent include an alkoxy group having 1 to 6 carbon atoms, an allyloxy group and the like. Specific examples of the compound represented by the general formula (III) include (III-1) to (III-9) shown below, but the compound is not limited to these. Above all, the developer (I
-10) and the good effect when used (III-
1) is preferably used.

[0016]

Embedded image

In the present invention, the general formulas (II) and (III)
If the content of the sensitizer represented by the formula (1) is less than 0.01 part with respect to 1 part of the developer represented by the general formula (I), the sensitizing effect is not sufficient and 1 part of the developer is contained. On the other hand, when the content is more than 2 parts, a sufficient color density cannot be obtained. Therefore, the sensitizers represented by the general formulas (II) and (III) should be used in a proportion of 0.01 to 2 parts with respect to 1 part of the developer represented by the general formula (I). desirable.

Generally, in a thermosensitive recording medium, a dye and a developer are usually dispersed together with a binder, and if necessary, an auxiliary agent such as a sensitizer, a filler, an ultraviolet absorber, a water-proofing agent and a defoaming agent is added. To prepare a coating composition, which is applied onto a support and dried. As the dye to be used in the heat-sensitive recording material of the present invention, all known dyes in the field of conventional pressure-sensitive or heat-sensitive recording paper can be used and are not particularly limited, but triphenylmethane compounds and fluorane are usable. Preferred are system compounds, fluorene compounds and divinyl compounds. Specific examples of typical basic colorless dyes are shown below. These basic colorless dyes may 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 [ Another name: Malachite green lactone] <Fluoran-based leuco dye> 3-diethylamino-6-methylfluorane 3-diethylamino-6-methyl-7-anilinofluorane 3-diethylamino-6-methyl-7- (o, p-dimethyl Anilino) fluorane 3-diethylamino-6-methyl-7-chlorofluorane 3-diethylamino-6-methyl-7- (m-trifluoromethylanilino) fluorane 3-diethylamino-6-methyl-7- (o- Chloroanilino) fluorane 3-diethylamino-6-methyl Lu-7- (p-chloroanilino) fluorane 3-diethylamino-6-methyl-7- (o-fluoroanilino) fluorane 3-diethylamino-6-methyl-7-n-octylanilinofluorane 3-diethylamino-6 -Methyl-7-n-octylaminofluorane 3-diethylamino-6-methyl-7-benzylanilinofluorane 3-diethylamino-6-methyl-7-dibenzylanilinofluorane 3-diethylamino-6-chloro- 7-Methylfluorane 3-diethylamino-6-chloro-7-anilinofluorane 3-diethylamino-6-chloro-7-p-methylanilinofluorane 3-diethylamino-6-ethoxyethyl-7-anilinoflu Oran 3-diethylamino-7-methylfluorane 3-diethylamino- -Chlorofluorane 3-diethylamino-7- (m-trifluoromethylanilino) fluorane 3-diethylamino-7- (o-chloroanilino) fluorane 3-diethylamino-7- (p-chloroanilino) fluorane 3-diethylamino-7- (O-Fluoroanilino) fluorane 3-diethylamino-benzo [a] fluorane 3-diethylamino-benzo [c] fluorane 3-dibutylamino-6-methyl-fluorane 3-dibutylamino-6-methyl-7-anilinoflu Oran 3-dibutylamino-6-methyl-7- (o, p-dimethylanilino) fluorane 3-dibutylamino-6-methyl-7- (o-chloroanilino) fluorane 3-dibutylamino-6-methyl-7- (P-chloroanilino) fluorane 3-dibutyl Amino-6-methyl-7- (o-fluoroanilino) fluorane 3-dibutylamino-6-methyl-7- (m-trifluoromethylanilino) fluorane 3-dibutylamino-6-methyl-chlorofluorane 3 -Dibutylamino-6-ethoxyethyl-7-anilinofluorane 3-dibutylamino-6-chloro-7-anilinofluorane 3-dibutylamino-6-methyl-7-p-methylanilinofluorane 3- Dibutylamino-7- (o-chloroanilino) fluorane 3-dibutylamino-7- (o-fluoroanilino) fluorane 3-n-dipentylamino-6-methyl-7-anilinofluorane 3-n-dipentylamino- 6-Methyl-7- (p-chloroanilino) fluorane 3-n-dipentylamino-7- (m-trifluor Romethylanilino) fluorane 3-n-dipentylamino-6-chloro-7-anilinofluorane 3-n-dipentylamino-7- (p-chloroanilino) fluorane 3-pyrrolidino-6-methyl-7-anilinofluorane 3 -Piperidino-6-methyl-7-anilinofluorane 3- (N-methyl-N-propylamino) -6-methyl-7-anilinofluorane 3- (N-methyl-N-cyclohexylamino) -6 −
Methyl-7-anilinofluorane 3- (N-ethyl-N-cyclohexylamino) -6-
Methyl-7-anilinofluorane 3- (N-ethyl-N-xylamino) -6-methyl-
7- (p-chloroanilino) fluorane 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- (N-ethyl-N-ethoxypropylamino) -6
-Methyl-7-anilinofluoran 3-cyclohexylamino-6-chlorofluoran 2- (4-oxahexyl) -3-dimethylamino-6
-Methyl-7-anilinofluorane 2- (4-oxahexyl) -3-diethylamino-6
-Methyl-7-anilinofluoran 2- (4-oxahexyl) -3-dipropylamino-
6-methyl-7-anilinofluorane 2-methyl-6-p- (p-dimethylaminophenyl)
Aminoanilinofluorane 2-Methoxy-6-p- (p-dimethylaminophenyl) aminoanilinofluorane 2-chloro-3-methyl-6-p- (p-phenylaminophenyl) aminoanilinofluorane 2 -Chloro-6-p- (p-dimethylaminophenyl)
Aminoanilinofluoran 2-nitro-6-p- (p-diethylaminophenyl)
Aminoanilinofluorane 0 2-amino-6-p- (p-diethylaminophenyl) aminoanilinofluorane 2-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluorane 2-phenyl-6- Methyl-6-p- (p-phenylaminophenyl) aminoanilinofluorane 2-benzyl-6-p- (p-phenylaminophenyl) aminoanilinofluorane 2-hydroxy-6-p- (p-phenyl Aminophenyl) aminoanilinofluorane 3-methyl-6-p- (p-dimethylaminophenyl)
Aminoanilinofluorane 3-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluorane 3-diethylamino-6-p- (p-dibutylaminophenyl) aminoanilinofluorane 2,4-dimethyl- 6-[(4-Dimethylamino) anilino] -fluorane <fluorene-based leuco dye>3,6,6'-tris (dimethylamino) spiro [fluorene-9,3'-phthalide] 3,6,6'-tris (Diethylamino) spiro [fluorene-9,3'-phthalide] <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> 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) fluorane-γ- (3
′ -Nitro) anilinolactam 3,6-bis (diethylamino) fluorane-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

In the present invention, conventionally known sensitizers can be used as long as the desired effects for the above problems are not impaired. Examples of such a sensitizer include fatty acid amides such as stearic acid amide and palmitic acid amide, ethylene bisamide, montanic acid wax, polyethylene wax, 1,2-di- (3-methylphenoxy) ethane, p-benzylbiphenyl, β- Benzyloxynaphthalene, 4-biphenyl-p-tolyl ether, m-terphenyl, 1,2-diphenoxyethane, dibenzyl oxalate, di (p-chlorobenzyl oxalate), di (p-methylbenzyl) oxalate, Dibenzyl terephthalate, benzyl p-benzyloxybenzoate, di-p-tolyl carbonate, phenyl-α-naphthyl carbonate, 1,4-diethoxynaphthalene, 1-hydroxy-
Examples thereof include 2-naphthoic acid phenyl ester, o-xylelin-bis- (phenyl ether), and 4- (m-methylphenoxymethyl) biphenyl, but they are not particularly limited thereto. 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 polymerization degree of 200 to 1900, partially saponified polyvinyl alcohol, carboxy modified polyvinyl alcohol, amide modified polyvinyl alcohol, sulfonic acid modified polyvinyl alcohol, butyral modified polyvinyl. Modified polyvinyl alcohol such as alcohol, cellulose derivative such as hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, acetyl cellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer, polyvinyl chloride, polyvinyl acetate, polyacrylamide , Polyacrylic acid ester, polyvinyl butyral, polystyrene and their copolymers, polyamide resin, silicone Butter, petroleum resins, terpene resins, ketone resins, and coumarone resins. These polymeric substances are water, alcohols, ketones, esters,
In addition to being used by being dissolved in a solvent such as a hydrocarbon, it may be used in a state of being emulsified in water or another medium or dispersed in a paste form, and may be used together depending on the required quality.

In the present invention, p-nitrobenzoic acid metal salt (Ca, Zn), which is a known stabilizer showing an oil resistance effect of a recorded image, etc., within a range that does not impair the desired effect on the above problems, Alternatively, phthalic acid monobenzyl ester metal salt (Ca, Zn) can be added.

As the filler which can be used in the present invention, silica, calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, talc, titanium oxide, zinc oxide, aluminum hydroxide, polystyrene resin, urea-formalin resin, styrene- Examples thereof include methacrylic acid copolymers, styrene-butadiene copolymers, and inorganic or organic fillers such as hollow plastic pigments.

In addition, release agents such as fatty acid metal salts, lubricants such as waxes, benzophenone-based and triazole-based UV absorbers, waterproofing agents such as glyoxal, dispersants, defoamers, antioxidants, and fluorescent agents. A dye or the like can be used.

The amount of the color developer and the dye used in the heat-sensitive recording material of the present invention and the type and amount of other various components are determined according to the required performance and recording suitability, and are not particularly limited, but are usually , A developer 1 represented by the general formula (I)
To 0.1 part by weight of basic colorless dye, the general formula (I
0.01 to 2 parts of the compound represented by I) or (III) and 0.5 to 4 parts of a filler are used, and the binder is 5 to 5 in the total solid content.
25% is appropriate.

As the support, paper, synthetic paper, plastic film, non-woven fabric, metal foil or the like can be used, and a composite sheet in which these are combined may be used. The desired thermosensitive recording medium can be obtained by applying a coating solution having the above composition to any one of these supports. Further, an overcoat layer of a polymer substance or the like may be provided on the thermosensitive color developing layer for the purpose of enhancing the storage stability. Further, an undercoat layer containing an organic filler or an inorganic filler may be provided between the color forming layer and the support for the purpose of enhancing the storage stability and sensitivity.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The heat-sensitive recording material of the present invention comprises a basic colorless dye, at least one aminobenzenesulfonamide derivative represented by the general formula (I) as a developer, and a sensitizer. At least one kind of compound represented by the general formula (II) or (III) is dispersed together with a binder, and a thermosensitive color-forming layer coating liquid is prepared by adding a filler and other additives as necessary. Can be obtained by coating on a support and drying. General formula (II) or (III)
The compound represented by is a developer 1 represented by the general formula (I).
It is used in a ratio of 0.01 to 2 parts with respect to parts.

Generally, a color developer having an acidic functional group such as a phenolic hydroxyl group or a carboxyl group has a high color developing ability. The aminobenzenesulfonamide derivative represented by the formula (I) used in the present invention does not have these functional groups, but exhibits a strong color developing ability for a basic dye. The reason for this is not clearly understood, but it is presumed as follows. The aminobenzenesulfonamide derivative used in the present invention is considered to undergo a structural change (tautomerism) from a neutral type to an acidic type as shown in the following formula under certain conditions. Functions as a colorant.
A high temperature is required to cause the tautomerism from the neutral type to the acidic type, and in the case of a thermosensitive recording medium, the thermal head momentarily reaches a high temperature of 200 to 300 ° C. or more, and therefore the recording layer of the thermosensitive recording medium. The compound represented by the formula (I) contained therein undergoes tautomerism to become an acidic form and develops a color developing ability.
It is considered that this causes the lactone ring of the dye to be cleaved to develop a color.

[0029]

Embedded image (In the formula, X represents an oxygen atom or a sulfur atom)

The formula (II) used in the present invention
Alternatively, the sensitizer represented by (III) has an action of inducing a structural change from the neutral type to the acidic type of the developer when melted together with the developer represented by the formula (I). it is conceivable that.

[0031]

【Example】

<Production of Thermal Recording Material> The thermal recording material of the present invention will be described below with reference to examples. The parts and% in the description represent parts by weight and% by weight, respectively, unless otherwise specified.

[Examples 1 to 5] In Examples 1 to 5, compounds (I-1) and (I) were used as color developers in the heat-sensitive recording material of the present invention.
-10), (I-13), (I-19) or (I-2
6), 3-diethylamino-6-as a basic colorless dye
In this example, methyl-7-anilinofluorane (ODB) and compound (II-1) were used as a sensitizer. Dispersing liquid of developer (A liquid) and basic colorless dye dispersion (B
Liquid) and the sensitizer dispersion (C liquid) were separately wet-milled with a sand grinder until the average particle diameter became 1 micron. A liquid (developing agent dispersion liquid) Developer 6.0 parts 10% polyvinyl alcohol aqueous solution 18.8 parts Water 11.2 parts Liquid B (basic colorless dye dispersion liquid) 3-diethylamino-6-methyl- 7-anilinofluoran (ODB) 2.0 parts 10% polyvinyl alcohol aqueous solution 4.6 parts water 2.6 parts solution C (sensitizer dispersion) compound (II-1) 4.0 parts 10% Polyvinyl alcohol aqueous solution 18.8 parts Water 11.2 parts Next, the dispersions were mixed and stirred at the following ratios to prepare coating solutions. Liquid A (developer dispersion liquid) 36.0 parts Liquid B (basic colorless dye [ODB] dispersion liquid) 9.2 parts Liquid C (sensitizer [compound (II-1)] dispersion liquid) 34.0 Part Kaolin clay (50% dispersion liquid) 12.0 parts Each of the above coating liquids was applied to one side of a base paper of 50 g / m ² and then dried, and this sheet was smoothed with a super calender. Was applied for 500 to 600 seconds to obtain a thermal recording material having a coating amount of 6.0 g / m ² .

[Examples 6 to 8] In Examples 6 to 8, the compound (I-10) was used as the developer and the OD was used as the basic colorless dye.
It is an example of using the basic colorless dyes shown below other than B and the compound (II-1) as a sensitizer. (Basic colorless dye) ODB-2; 3-dibutylamino-6-methyl-7-anilinofluorane PSD-170; 3-pyrrolidino-6-methyl-7-anilinofluorane CVL; 3,3-bis (P-dimethylaminophenyl)
-6-Dimethylaminophthalide The developer dispersion of compound (I-10) and the sensitizer dispersion of compound (II-1) were treated in the same manner as in Examples 1 to 5. The basic colorless dye dispersion liquid (D liquid) other than ODB was separately wet-milled with a sand grinder until the average particle diameter became 1 micron. Liquid D (basic colorless dye dispersion other than ODB) Basic colorless dye 2.0 parts 10% polyvinyl alcohol aqueous solution 4.6 parts water 2.6 parts Next, the dispersions are mixed and stirred at the following ratios. Then, the coating liquid was prepared. Liquid A (developer [Compound (I-10)] dispersion) 36.0 parts Liquid D (basic colorless dye dispersion other than ODB) 9.2 parts Liquid C (sensitizer [compound (II-1 )] Dispersion) 34.0 parts Kaolin clay (50% dispersion) 12.0 parts Each of the above coating solutions is applied to one side of a 50 g / m ² base paper and then dried to obtain a sheet. -A calender was applied so that the smoothness was 500 to 600 seconds, and a coating amount of 6.0 g / m ² was obtained.

[Examples 9 to 15] In Examples 9 to 15, the compound (I-10) was used as the developer, the ODB was used as the basic colorless dye, and the compounds (II-2) and (II-6) were used as the sensitizer. ),
(II-8), (II-10), (III-1), (III-
It is an example using 8) and (III-9). Example 1
The developer dispersion and the ODB dispersion of the compound (I-10) were treated in the same manner as in 5, and the compounds (II-2) to (III-
9) is treated in the same manner as compound (II-1) to prepare dispersion E.
A liquid was obtained. Then mix and stir the dispersions at the following ratios,
The coating liquid was adjusted. Liquid A (developer [compound (I-10)] dispersion liquid) 36.0 parts Liquid D (basic colorless dye [ODB] dispersion liquid) 9.2 parts Liquid E (sensitizer dispersion liquid) 34.0 Part Kaolin clay (50% dispersion liquid) 12.0 parts Each of the above coating liquids was applied to one side of a base paper of 50 g / m ² and then dried, and this sheet was smoothed with a super calender. Was applied for 500 to 600 seconds to obtain a thermal recording material having a coating amount of 6.0 g / m ² .

[Example 16] In Example 16, compounds (I-1) and (I-10) were used as developers, ODB was used as a basic colorless dye, and compound (II-1) was used as a sensitizer. Here is an example. In the same manner as in Examples 1 to 5, the compound (I-
1) and (I-10) developer dispersion, ODB dispersion,
And a sensitizer dispersion of the compound (II-1) was processed. Next, the dispersions were mixed and stirred at the following ratios to prepare coating solutions. Liquid A (developer [compound (I-1)] dispersion liquid) 18.0 parts Liquid A (developer [compound (I-10)] dispersion liquid) 18.0 parts Liquid B (basic colorless dye [ ODB] Dispersion) 9.2 parts C liquid (sensitizer [compound (II-1)] dispersion) 34.0 parts Kaolin clay (50% dispersion) 12.0 parts 50 g / m of the above coating solutions. After applying to one side of the base paper of No. ^2, the sheet was dried, and this sheet was treated with a super calender so that the smoothness was 500 to 600 seconds, and the applied amount was 6.0 g / m ^2. A thermosensitive recording medium was obtained.

[Example 17] Example 17 is an example in which the compound (I-10) was used as the color developer, ODB and PSD-170 were used as the basic colorless dye, and the compound (II-1) was used as the sensitizer. is there. In the same manner as in Examples 1 to 8, the compound (I
-10) Developer dispersion, ODB dispersion and PSD-1
70 dispersions and a sensitizer dispersion of compound (II-1) were processed. Next, the dispersions were mixed and stirred at the following ratios to prepare coating solutions. Liquid A (developer [Compound (I-10)] dispersion liquid) 36.0 parts Liquid B (basic colorless dye [ODB] dispersion liquid) 4.6 parts Liquid D (basic colorless dye [PSD-170] Dispersion liquid) 4.6 parts C liquid (sensitizer [compound (II-1)] dispersion liquid) 34.0 parts Kaolin clay (50% dispersion liquid) 12.0 parts Each of the above coating liquids of 50 g / m ² After coating on one side of the base paper, it is dried, and this sheet is treated with a super calender to have a smoothness of 500 to 600 seconds, and the coating amount is 6.0 g / m ² thermal recording. Got the body

Example 18 In Example 18, the compound (I-10) was used as the color developer, and ODB was used as the basic colorless dye.
In this example, compounds (II-1) and (III-1) were used as sensitizers. In the same manner as in Examples 1 to 15, the compound (I
-10) developer dispersion, ODB dispersion, compound (II-
The sensitizer dispersion liquid of 1) and the compound (III-1) was processed. Next, the dispersions were mixed and stirred at the following ratios to prepare coating solutions. Liquid A (developer [Compound (I-10)] dispersion liquid) 36.0 parts Liquid D (basic colorless dye [ODB] dispersion liquid) 9.2 parts Liquid C (sensitizer [compound (II-1) )] Dispersion) 17.0 parts E solution (sensitizer [compound (III-1)] dispersion) 17.0 parts Kaolin clay (50% dispersion) 12.0 parts 50 g / m of each coating solution After applying to one side of the base paper of No. ^2, the sheet was dried, and this sheet was treated with a super calender so that the smoothness was 500 to 600 seconds, and the applied amount was 6.0 g / m ^2. A thermosensitive recording medium was obtained.

Comparative Example 1 The same operation as in Example 2 was performed. However, Dispersion E was not mixed in the formation of the color forming layer.

Comparative Example 2 The same operation as in Example 2 was performed. However, the compound (II-
P-Benzylbiphenyl (PBB) was used instead of 1).

<Evaluation of Thermal Recording Material> The thermal recording material thus prepared was subjected to an applied energy of 0 by using TH-PMD (a thermal recording paper printing tester, Kyocera, equipped with a thermal head) manufactured by Okura Electric Co., Ltd. .30 and 0.38 mj / dot
Printed with. The recording density of the recording unit was measured using a Macbeth densitometer (R
D-914, Amber filter used) (see Table 1).

[0041]

[Table 1]

As is clear from Table 1 above, when the compound represented by the general formula (I) is used as the color developer, the combination of the compound represented by the general formula (II) or (III) gives a high recording performance. Sensitivity is shown. On the other hand, in Comparative Example 2 in which other sensitizers were used, sufficient coloring ability was not obtained.
Alternatively, it can be seen that the compound represented by (III) has a remarkable sensitizing effect.

[0043]

The thermosensitive recording medium of the present invention has the above general formula (II) or (II) when the aminobenzenesulfonamide derivative represented by the above general formula (I) is used as the color developer.
By containing the compound represented by I) as a sensitizer, the color development sensitivity is high and the recorded image is good. Therefore, a high density and clear image can be obtained even with a small amount of thermal energy, and it is suitable for high-speed printing and equipment with small applied energy, and is highly practical.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kyosho Nagai 1-30-6 Kamiochiai, Shinjuku-ku, Tokyo Inside Nippon Paper Industries Co., Ltd. Product Development Laboratory (72) Inventor Akio Sekine 5-21, Oji, Kita-ku, Tokyo No. 1 Central Research Institute of Nippon Paper Industries Co., Ltd. (72) Inventor Toshio Kaneko 1-30-6 Kamiochiai, Shinjuku-ku, Tokyo Inside Nippon Paper Industries Co., Ltd. Product Development Laboratory

Claims (1)

[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 developing agent as main components, wherein the thermosensitive coloring layer is an organic developing agent. As a sensitizer, a compound represented by the following general formula (II) or (III)
A thermosensitive recording medium comprising at least one kind in a proportion of 0.01 to 2 parts per part. Embedded image (In the formula, X represents an oxygen atom or a sulfur atom, and Y represents 1 carbon atom.
~ 6 represents a lower alkyl group or an electron-withdrawing group, and l represents an integer of 0-4. R represents an unsubstituted or substituted phenyl group, an aralkyl group, a lower alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a lower alkenyl group having 2 to 6 carbon atoms, or a naphthyl group. ) (In the formula, R ₁ and R ₂ are a halogen atom or a carbon number of 1 to
6 represents an alkyl group, and m and n represent an integer of 0-2. ) (In the formula, R ₃ and R ₄ represent a hydrogen atom, an alkoxy group having 1 to 6 carbon atoms or an allyloxy group.)