JPH08244355A - Thermal recording material - Google Patents

Abstract

PURPOSE: To provide excellent ground color stability and excellent color developability by using bisurea compound having both carboxyl group and hydroxyl group as developer. CONSTITUTION: The thermal recording material comprises a colorless of pale dye precursor, a thermal color developing layer containing developer for color developing the precursor in reaction at the time of heating. The developer is bisurea compound represented by a formula. The color developing layer contains at least one type of the bisurea compounds. In the formula, X is 1-6C alkyl group, halogen atom or hydrogen atom, and A is bivalent group of at most 30C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material excellent in stability of a background color portion (white paper portion).

[0002]

2. Description of the Related Art Generally, a heat-sensitive recording material is prepared by grinding and dispersing a colorless or light-colored electron-donating colorless dye and a color developing agent such as a phenolic compound into fine particles, and then mixing the two. A coating liquid obtained by adding a binder, a filler, a sensitivity improver, a lubricant, and other auxiliaries to a support such as paper, synthetic paper, film, plastic, etc.,
A visible record is obtained by color development by an instant chemical reaction caused by heating with a thermal head, hot stamp, laser light or the like.

The thermosensitive recording medium is applied to a wide range of fields such as a measuring recorder, a computer terminal printer, a facsimile, an automatic ticket vending machine and a bar code label. However, with the recent diversification of recording devices for thermal recording media and the progress of higher performance, the quality required for thermal recording media has become higher and more difficult. For example, from the viewpoint of speeding up recording, there is a demand for a heat-sensitive recording material that can obtain a color image with a high recording density even with a smaller heat energy. On the other hand, from the viewpoint of storage stability of the recording material, there is a demand for a thermal recording material having excellent light resistance, oil resistance, water resistance, solvent resistance and the like.

With the spread of plain paper recording systems such as electrophotographic systems and ink jet systems, thermal recording systems are often compared with these plain paper recording systems. Therefore, for example, the stability of the recording portion (image) of the thermal recording material or the stability of the non-recording portion before and after recording (called the background color portion or the blank sheet portion) (hereinafter referred to as background color stability) , Etc.) is required to approach the same quality as the plain paper recording method. Among them, particularly, the thermal recording material is required to have background color stability against heat and solvent (hereinafter referred to as background color heat resistance and background color solvent resistance, respectively). In other words, it can be said that the recording body is, so to speak, “heat-sensitive” only during recording and is “non-heat-sensitive” except during recording.

Regarding the background color stability of the thermal recording material, for example,
Japanese Patent Laid-Open No. 4-353490 discloses a heat-sensitive recording material having relatively good ground color stability even under a high temperature condition of about 90 ° C. This heat-sensitive recording material is characterized by containing a 4-hydroxydiphenylsulfone compound and a metal salt of phosphate.

[0006]

The background color stability of the thermosensitive recording medium disclosed in Japanese Patent Laid-Open No. 4-353490 is 95% in a dryer.
When processed at 5 ℃ for 5 hours, the Macbeth density of the background color is about 0.11 and shows a considerable stability, but it is still insufficient in terms of the stability of the background color at a temperature higher than that, for example, 120 ℃. there were. Therefore, it is an object of the present invention to provide a thermosensitive recording medium which has excellent ground color stability and good color development.

[0007]

Means for Solving the Problems The above problems were solved by a thermosensitive recording medium using a bisurea compound having both a carboxyl group and a hydroxyl group as a developer. JP-A-53-140043, JP-A-57-87993 and JP-A-
57-82787, JP-A-59-67083, etc.,
A heat-sensitive recording material is disclosed in which a urea compound and a phenol-based developer (a phenol compound conventionally known as a developer such as bisphenol A and bisphenol S) are used in combination. In these publications, the urea compound has only a limited number of carbon atoms, and is basically used only as a melting point adjusting agent for a phenol-based developer. However, a heat-sensitive recording material containing a urea compound and a phenol-based color developer in combination could not obtain sufficient heat resistance against background color.

Patents using a specific monourea compound in a heat-sensitive recording material are disclosed in JP-A-58-211496, JP-A-59-184694 and JP-A-61-211085. There is. The monourea compound used in these publications is a urea compound in which only one amino group portion of urea is substituted. However, a heat-sensitive recording material using this urea compound alone as a color developer also did not show sufficient background color heat resistance. Also in these publications,
It was used in combination with a phenol-based developer, and with this combination, good ground color heat resistance could not be obtained.

Further, a heat-sensitive recording material using a bisurea compound is disclosed in Japanese Patent Application Laid-Open Nos. 5-31752 and 5-147357.
It is disclosed in Japanese Patent Application Laid-Open Nos. 5-148220, 6-227142, and the like. JP-A-5-131752, JP-A-5-147357
The bisurea compound described in JP-A No. 5-148220 or JP-A No. 5-148220 has a structure in which a sulfonyl group is adjacent to a urea structure (Ar—SO ₂ —NH—C (═O) —NH—)
It is characterized by having individual pieces. However, even these urea compounds have insufficient heat resistance under high temperature conditions of 120 ° C or higher. On the other hand, the bisurea compound described in JP-A-6-227142 is a compound in which two arylureido structures (Ar-NH-C (= O) -NH-) are linked by a diphenyl derivative. In this publication, the aryl group having an arylureido structure is exemplified by a halogen-substituted group and an unsubstituted group, but no description is given of the case of having a carboxyl group (—COOH) or a hydroxyl group. In this urea compound,
Although it is possible to obtain heat resistance under high temperature conditions of 120 ° C or higher, there is a drawback that the color development sensitivity is insufficient.

The inventors of the present invention use a specific bisurea compound (bisurea compound having both a carboxyl group and a hydroxyl group) as a developer.
It has been found that a thermal recording material having excellent ground color stability and good color development sensitivity can be obtained, and the present invention has been completed.

That is, the present invention provides a thermosensitive recording material having a thermosensitive coloring layer containing a colorless or pale color dye precursor and a developer which reacts when heated to develop the dye precursor. Is a bisurea compound represented by the following general formula (1), wherein the thermosensitive coloring layer contains at least one kind of the bisurea compound.

[0012]

[Chemical 4] (Here, X represents an alkyl group having 1 to 6 carbon atoms, a halogen atom, or a hydrogen atom. A represents a divalent group having 30 or less carbon atoms.)

The bisurea compound represented by the general formula (1) used in the present invention has an arylureido structure ((HOOC) (HO) -Ar- having both a carboxyl group and a hydroxyl group.
It can be considered that the two NH-C (= O) -NH-) are bisurea compounds linked by a joint group (A). When the bisurea compounds are roughly classified by the joint group, they are classified as follows, for example.

The joint group is a linear alkylene group having 1 to 12 carbon atoms (methylene group, ethylene group, n-propylene group, n-butylene group, n-pentamethylene group, n-hexamethylene group, n- Heptamethylene group, n-octamethylene group,
Bisurea compound which is n-nonamethylene group, n-decamethylene group, n-undecamethylene group, n-dodecamethylene group). A bisurea compound whose joint group is an alkylene group having a branched chain of 1 to 15 carbon atoms. A bisurea compound whose joint group is a linear alkylene group having a nitrogen atom or an oxygen atom in a straight chain and having 1 to 12 carbon atoms. A bisurea compound in which the joint group is a group having 3 to 20 carbon atoms and containing at least one substituted or unsubstituted cycloalkyl ring. More specifically, a bisurea compound in which two arylureido structures are directly linked to one cycloalkyl ring (such as a cyclohexyl ring),
Biurea compounds in which one arylureido structure is bonded to a dicycloalkylalkyl (eg, dicyclohexylmethane, dicyclohexylethane, etc.) and two arylureido structures are bonded to an alkyl group portion of the dialkylcycloalkyl. It can be divided into bisurea compounds and the like. A bisurea compound in which the joint group is a group containing one substituted or unsubstituted aromatic ring (benzene ring, naphthalene ring, etc.). When further classified, two arylureido structures are directly linked to one substituted or unsubstituted aromatic ring (benzene, toluene, xylene, naphthalene, etc.), a bisurea compound, and two arylureido structures are two. And a bisurea compound bonded to the alkyl group portion of the aromatic ring substituted with the alkyl group. A bisurea compound in which the joint group is a group containing two or more substituted or unsubstituted aromatic rings (benzene ring, naphthalene ring, etc.). For example, a bisurea compound in which two arylureido structures are bonded to a diphenyl compound (diphenylmethane, diphenylethane, diphenyl ether, diphenyl sulfone, diphenyl sulfide, benzophenone, etc.) can be mentioned. Besides this,
It is also possible that the joint group is a group having an isophorone ring or a group having a piperazine ring.

Considering the joint group, regarding the joint group (A) of the bisurea compound represented by the general formula (1), the thermosensitive recording produced such as the melting point, the decomposition temperature of the bisurea compound and the solubility in a solvent. It should be appropriately selected depending on the physical performance (recording density, stability of recording area, background color stability, etc.) or ease of synthesis (availability of raw materials, reaction yield, etc.), and is not particularly limited. Not something. However, from the viewpoint of recording density, it is most preferable that the joint group is a linear alkylene group having 1 to 12 carbon atoms.

That is, in a thermosensitive recording material having a thermosensitive coloring layer containing a colorless or light-colored dye precursor and a developer which reacts when heated to develop the dye precursor, the developer has the following general formula: A thermosensitive recording medium represented by (2), wherein the thermosensitive color developing layer contains at least one kind of the bisurea compound is more preferable.

[0017]

Embedded image (Here, X represents an alkyl group having 1 to 6 carbon atoms, a halogen atom, or a hydrogen atom. Further, n is 1 to 12
Represents the integer. )

When the joint group is a group containing two or more substituted or unsubstituted aromatic rings (benzene ring, naphthalene ring, etc.), the melting point of the bisurea compound is high, which is high. Recording density cannot be obtained.

On the other hand, considering the arylureido structure having carboxyl groups at both terminals, the substituent (X) on the aromatic ring of the arylureido structure portion of the bisurea compound represented by the general formula (1) or (2). Also,
It should be appropriately selected depending on the melting point of the bisurea compound, the decomposition temperature, the solubility in a solvent, or the like, or the performance of the heat-sensitive recording material to be manufactured (recording density, recording portion stability, background color stability, etc.), It is not particularly limited.
However, when comprehensively considering the recording density, the availability of synthetic raw materials, the ground color stability, and the economical efficiency (cost), the case where the substituent (X) on the aromatic ring is a hydrogen atom provides the best balance, Most preferred.

Regarding the carboxyl group of the arylureido structure portion of the bisurea compound represented by the general formula (1) or (2), the carboxyl group is different from the ureido structure in terms of heat resistance against background color. More preferably, it is located at the para position or the meta position.

The bisurea compound represented by the general formula (1) or (2) is, for example, a reaction of (1) an aminohydroxybenzoic acid derivative and a diisocyanate compound (reaction of the formula (a)), (2) hydroxybenzoic acid. It can be easily synthesized by a reaction between an isocyanate derivative of an acid and a diamine (reaction of formula (a)).

[0022]

[Chemical 6]

Among these reactions, the reaction of the formula (a) is the most advantageous method from the viewpoints of availability of raw materials, simplicity of the reaction and the like. When synthesizing by the reaction of (a),
The joint group is derived from the structure of the diisocyanate compound. Therefore, when selecting a joint group, a joint group derived from a diisocyanate compound described later is more preferable in terms of availability.

In the case of the reaction of the formula (a), for example, as aminohydroxybenzoic acid derivatives, 2-amino-3-hydroxybenzoic acid, 2-amino-5-hydroxybenzoic acid, 3-amino-2-hydroxybenzoic acid are used. (3-aminosalicylic acid), 3-
Amino-4-hydroxybenzoic acid, 4-amino-2-hydroxybenzoic acid (4-aminosalicylic acid), 4-amino-3-hydroxybenzoic acid, 5-amino-2-hydroxybenzoic acid (5-
Aminosalicylic acid), 2-amino-3-hydroxy-4-methylbenzoic acid, 3-amino-2-hydroxy-4-methylbenzoic acid, 4-amino-5-chloro-3-hydroxybenzoic acid and the like, On the other hand, as the diisocyanate compound, 2,4-
Toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), tolidine diisocyanate (TODI) , Hexamethylene diisocyanate (HD
I), isophorone diisocyanate (IPDI), p-phenylene diisocyanate, m-phenylene diisocyanate, transcyclohexane-1,4-diisocyanate, xylylene diisocyanate (XDI), 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MD
I), lysine diisocyanate (LDI), m-tetramethylxylene diisocyanate (m-TMXDI), p-tetramethylxylene diisocyanate (p-TMXDI)
Etc., and can be selected from both in any combination.

Specific examples of the bisurea compound represented by the general formula (1) or (2) include the following compounds.

[0026]

[Chemical 7]

Embedded image

[0027]

[Chemical 9]

[Chemical 10]

[0028]

[Chemical 11]

[Chemical 12]

[0029]

[Chemical 13]

Embedded image

The bisurea compound represented by the general formula (1) or (2) may be converted into a zinc derivative (zinc salt, zinc complex compound, mixture with zinc compound, etc.) for use. In particular, when it is desired to obtain the recording sensitivity of the manufactured thermosensitive recording medium, it is possible to improve the sensitivity.

That is, in a thermosensitive recording material having a thermosensitive coloring layer containing a colorless or light-colored dye precursor and a developer which reacts when heated to develop the dye precursor, the developer has the following general formula: A heat sensitive recording material, which is a zinc derivative of a bis-urea compound represented by (3), characterized in that the heat-sensitive color forming layer contains at least one kind of the bis-urea compound.

[0032]

[Chemical 15] (Here, X represents an alkyl group having 1 to 6 carbon atoms, a halogen atom, or a hydrogen atom. Further, n is 1 to 12
Represents the integer. )

Among the zinc derivatives of the bis-urea compound represented by the general formula (3), the zinc derivative of the bis-urea compound having a structure in which a carboxyl group and a hydroxyl group are adjacent to each other, that is, a salicylic acid structure, is the most preferable in terms of recording sensitivity. Is.

The zinc derivative of the bis-urea compound represented by the general formula (3) is described in detail, for example, in "New Experimental Chemistry Course 8-II" (Maruzen Co., Ltd., 1977), page 987. It may be prepared from the bisurea compound represented by the general formula (1) or (2) according to a synthetic method, a salicylate synthesis method, or the like.

The bisurea compound represented by the general formula (1) or (2) is not limited to the zinc derivative, but may be in the form of an aluminum derivative, a calcium derivative, or a magnesium derivative.

Further, the bisurea compound represented by the general formula (1) or (2) of the present invention (particularly salicylic acid type compound) is a zinc compound, an aluminum compound, as disclosed in JP-B-6-49392. It may be of a type used in combination with a metal compound selected from magnesium compounds.

The heat-sensitive recording material using the bisurea compound represented by the general formula (1) or (2) or the zinc derivative of the bisurea compound represented by the general formula (3) of the present invention has a background color heat resistance. , And ground color are excellent in solvent resistance. That is, on the one hand, although the thermal head can record with a sufficient recording density, on the other hand, even if this recording medium is placed in a high temperature environment of 120 ° C. or higher, the recording surface (thermosensitive The ground color of the surface provided with the color forming layer) is substantially stable. Also, if you want to pursue heat resistance of the background color,
The bisurea compound represented by the general formula (1) or (2) is more preferable than the zinc derivative.

The heat-sensitive recording material of the present invention has high heat resistance against background color, and therefore, for example, (a) heat-laminate the recording surface after heat-sensitive recording with a plastic film or the like; It is also possible to use the sheet as a transfer sheet for heat transfer and to fix the toner on the surface of the heat-sensitive recording layer to heat-fix it, or (c) to heat-fix the toner on the heat-sensitive recording surface of the heat-sensitive recorded sheet.

Further, the thermosensitive recording medium of the present invention has an advantage that it is very easy to control the manufacturing process. That is, conventionally, in the production of a thermosensitive recording medium, the drying step after coating the thermosensitive coloring layer requires very strict temperature control so that the background coloring of the coated surface does not occur, and therefore high speed coating is also limited. was there. However, the thermal recording material of the present invention is
Since the background color does not develop even if hot air is applied, high-temperature drying in the drying process is possible, and the control range of the drying temperature can be greatly expanded, so it is possible to expect a dramatic improvement in productivity. it can.

Further, in the heat-sensitive recording material of the present invention, the discoloration due to the oil-based ink does not occur, probably because the bisurea compound or its zinc derivative used has a low solubility in an organic solvent. Therefore, it is also possible to write with an oil-based ink on the surface of the heat-sensitive recording layer of the heat-sensitive recording material.

Thus, the bisurea compound of the present invention,
And its zinc derivative are heat-sensitive recording materials excellent in ground color stability (ground color heat resistance, background color solvent resistance, etc.).

A general method for producing the thermosensitive recording medium of the present invention has (a) a dye precursor and (b) a bisurea compound of the present invention or a zinc derivative thereof as a developer having a dispersing function. This is a method in which each is dispersed together with a binder, an auxiliary agent such as a filler or a lubricant is added if necessary to prepare a coating liquid, and the coating liquid is applied onto a support by a usual method and dried.

The bisurea compound of the present invention and the zinc derivative thereof may be used alone or in combination. Further, for example, the specification of Japanese Patent Application No. 5-231105,
Japanese Patent Application No. 5-250328, Japanese Patent Application No. 5-250329, Japanese Patent Application No. 5-311502, Japanese Patent Application No. 5-315023, Japanese Patent Application No. 5-317211, Japanese Patent Application No. 5-321506, Japanese Patent Application No.
6-100082, Japanese Patent Application No. 6-14310, Japanese Patent Application No. 6-
No. 144159, Japanese Patent Application No. 6-144160, No. 6-14
No. 4161, Japanese Patent Application No. 6-184285, No. 7-9806
It is also possible to use it in combination with the urea compound described in Japanese Patent Application No. 7-21507.

Further, in principle, the thermosensitive recording medium of the present invention should not be used in combination with a phenol compound conventionally known as a color developer. When a phenol compound is used, the performance of the heat-sensitive recording material (recordability, heat resistance, solvent resistance, etc.) mainly depends on the phenol compound. Therefore, the heat-sensitive recording material used in combination with the phenol compound cannot obtain sufficient background color heat resistance. However, as long as the performance such as the background color stability (background color heat resistance, background color solvent resistance, etc.) of the heat-sensitive recording material to be produced is not impaired, a conventionally known developer for developing a dye precursor is developed. (For example, bisphenol A, bisphenol S, benzyl 4-hydroxybenzoate, 4-hydroxy-4′-isopropoxydiphenyl sulfone, etc.) may be used in combination in a small amount.

As the dye precursor used in the heat-sensitive recording material of the present invention, those conventionally known in the field of heat-sensitive recording can be used, and although not particularly limited, triphenylmethane leuco dyes, Fluoran-based leuco dyes and fluorene-based leuco dyes are preferred. Hereinafter, typical dye precursors will be exemplified.

3,3-bis (4'-dimethylaminophenyl)
-6-Dimethylaminophthalide (also known as crystal violet lactone (CVL)) 3,3-bis (4'-dimethylaminophenyl) -6-pyrrolidylphthalide 3,3-bis (4'-dimethylamino) Phenyl) phthalide (also known as malachite green lactone (MGL)) tris [4- (dimethylamino) phenyl] methane (also known as leuco crystal violet (LCV)) 3-dimethylamino-6-methyl-7- (m- Trifluoromethylanilino) fluorane 3-diethylamino-6-methyl-fluorane 3-diethylamino-7-methyl-fluorane 3-diethylamino-7-chloro-fluorane 3-diethylamino-6-methyl-7-chlorofluorane 3-diethylamino -6-Methyl-7-anilinofluorane 3-diethylamino-6-methyl-7-p-methylanilinofluorane 3-diethylamino-6-methyl-7- ( o, p-Dimethylanilino) fluorane 3-diethylamino-6-methyl-7- (m-trifluoromethylanilino) fluorane 3-diethylamino-6-methyl-7- (o-chloroanilino) fluorane 3-diethylamino-6 -Methyl-7- (p-chloroanilino) fluorane 3-diethylamino-6-methyl-7- (o-fluoroloanilino) fluorane 3-diethylamino-6-methyl-7- (pn-butylanilino)
Fluorane 3-diethylamino-6-methyl-7-n-octylaminofluorane 3-diethylamino-6-chloro-7-anilinofluorane 3-diethylamino-6-ethoxyethyl-7-anilinofluorane 3-diethylamino- Benzo [a] fluorane 3-diethylamino-benzo [c] fluorane 3-diethylamino-6-methyl-7-benzylaminofluorane 3-diethylamino-6-methyl-7-dibenzylaminofluorane 3-diethylamino-7-di (P-Methylbenzyl) aminofluorane 3-diethylamino-6-methyl-7-diphenylmethylaminofluorane 3-diethylamino-7-dinaphthylmethylaminofluorane 10-diethylamino-4-dimethylaminobenzo [a] fluorane 3 -Dibutylamino-7- (o-chloroanilino) fluorane 3-dibutylamino-6-methylfluorane 3-dibutylamino-6- Methyl-7-chlorofluorane 3-dibutylamino-6-methyl-7-anilinofluorane 3-dibutylamino-6-methyl-7-p-methylanilinofluorane 3-dibutylamino-6-methyl-7 -(o, p-Dimethylanilino) fluorane 3-dibutylamino-6-methyl-7- (m-trifluoromethylanilino) fluorane 3-dibutylamino-6-methyl-7- (o-chloroanilino) fluorane 3 -Dibutylamino-6-methyl-7- (p-chloroanilino) fluorane 3-dibuethylamino-6-methyl-7- (o-fluoroloanilino) fluorane 3-dibuethylamino-6-methyl-7- ( pn-Butylanilino) fluorane 3-dibutylamino-6-methyl-7-n-octylaminofluorane 3-dibutylamino-6-chloro-7-anilinofluorane 3-dibutylamino-6-ethoxyethyl-7-ani Rinofluorane 3-di-n-pentylamino-6-methyl-7-anilino Luoran 3-di-n-pentylamino-6-methyl-7- (o, p-dimethylanilino) fluorane 3-Di-n-pentylamino-6-methyl-7- (m-trifluoromethylanilino) fluorane 3 -Di-n-pentylamino-6-methyl-7- (o-chloroanilino) fluorane 3-di-n-pentylamino-6-methyl-7- (p-chloroanilino) fluorane 3-di-n-pentylamino-6-methyl -7- (o-Fluoroloanilino) fluorane 3-pyrrolidino-6-methyl-7-anilinofluorane 3-piperidino-6-methyl-7-anilinofluorane 3- (N-methyl-Nn-propyl Amino) -6-methyl-7-anilinofluorane 3- (N-ethyl-Nn-propylamino) -6-methyl-7-anilinofluorane 3- (N-ethyl-N-iso-propylamino) -6-methyl-7-
Anilinofluorane 3- (N-ethyl-Nn-butylamino) -6-methyl-7-anilinofluorane 3- (N-ethyl-N-iso-butylamino) -6-methyl-7-anilino Fluoran 3- (N-ethyl-Nn-hexylamino) -6-methyl-7-p-
Methylanilinofluorane 3- (N-ethyl-Nn-hexylamino) -6-methyl-7- (o,
p-Dimethylanilino) fluorane 3- (N-ethyl-Nn-hexylamino) -6-methyl-7- (m-
Trifluoromethylanilino) fluorane 3- (N-ethyl-Nn-hexylamino) -6-methyl-7- (o-
Chloroanilino) fluorane 3- (N-ethyl-N-iso-amylamino) -6-methyl-7-anilinofluorane 3- (N-ethyl-N-iso-amylamino) -6-chloro-7-anilinoflu Oran 3- (N-ethyl-N-3-methylbutylamino) -6-methyl-7
-Anilinofluoran 3- (N-ethyl-Np-toluidino) -6-methyl-7-anilinofluoran 3- (N-ethyl-Np-toluidino) -6-methyl-7- (p-methylanilino) Fluoran 3- (N-ethyl-Np-toluidino) -6-methyl-7- (o, p-dimethylanilino) fluoran 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-
Methyl-7-anilinofluorane 3- (N-cyclohexyl-N-methylamino) -6-methyl-7
-Anilinofluorane 3- (N-cyclohexyl-N-methylamino) -7-anilinofluorane 3- (N-ethyl-N-3-methoxypropylamino) -6-methyl-7-anilinofluorane 3- (N-Ethyl-N-3-ethoxypropylamino) -6-methyl-7-anilinofluorane 2- (4-oxahexyl) -3-dimethylamino-6-methyl
-7- Anilinofluorane 2- (4-oxahexyl) -3-diethylamino-6-methyl
-7- Anilinofluorane 2- (4-oxahexyl) -3-dipropylamino-6-methyl-7-anilinofluorane 3- (4``-aminostilbrudil-4'-amino)- 7,8-Benzofuran 3,6,6'- Tris (dimethylamino) spiro [fluorene
-9,3'-phthalide] 3,6,6'-tris (diethylamino) spiro [fluorene
-9,3'-phthalide] 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-diethylamino-2-n-hexylphenyl) -3- (1-
Ethyl-2-methylindol-3-yl) -4-azaphthalide 3- (4-cyclohexylmethylamino-2-methoxyphenyl) -3- (1-ethyl-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-methylindol-3-yl) phthalide 3,3-bis (2-methyl-1-octylindol-3-yl)
Phthalide 3- (1-Ethyl-2-methylindol-3-yl) -3- (1-
n-Butyl-2-methylindol-3-yl) phthalide 3,7-bis (dimethylamino) -10-benzoylphenothiazine 3,7-bis (dimethylamino) -N- [pN-bis (4,4 '-Dimethylaminophenyl) methylamino] benzoylphenothiazine 3,7-bis (dimethylamino) -N- [pN-bis (4,4'-diethylaminophenyl) methyl] benzoylphenothiazine 3,6-bis (diethylamino) fluorane- γ- (2'-nitro) anilinolactam 3,6-bis (diethylamino) fluorane-γ- (3'-nitro) anilinolactam 3,6-bis (diethylamino) fluorane-γ- (4'-nitro) Anilinolactam 3,6-bis (diethylamino) fluorane-γ-anilinolactam

These dye precursors may be used alone or in admixture of two or more. In the present invention, among these dye precursors, a fluoran dye precursor can be preferably used. Further, in particular, when importance is attached to thermal stability, naturally, a dye precursor having a high melting point and a high decomposition temperature is preferable.

In addition, in the heat-sensitive recording material of the present invention, in particular, when ground color heat resistance is required, it is generally preferable not to use a sensitizer. This is because when a sensitizer is used, the color development temperature depends on the melting point of the sensitizer. However, these may be used alone or in combination depending on the required performance of the manufactured thermal recording material. As the sensitizer used, 2-di (3-methylphenoxy) ethane, p-benzylbiphenyl, β-benzyloxynaphthalene, 1-
Hydroxy-2-naphthoic acid phenyl ester, dibenzyl terephthalate, benzyl p-benzyloxybenzoate, diphenyl carbonate, ditolyl carbonate, 4-biphenyl-p-
Trilyl ether, m-terphenyl, 1,2-diphenoxyethane, 1,2-bis (m-tolyloxy) ethane, 1,5-bis (p-methoxyphenoxy) -3-oxapentane, dibenzyl oxalate, shu Examples include acid di (p-methylbenzyl), oxalate di (p-chlorobenzyl), and the like.

As the binder which can be used in the heat-sensitive recording material of the present invention, a completely saponified polyvinyl alcohol having a polymerization degree of 200 to 1900, a partially saponified polyvinyl alcohol, a carboxy modified polyvinyl alcohol, an amide modified polyvinyl alcohol, and a sulfonic acid are used. Polyvinyl alcohols such as modified polyvinyl alcohol, butyral modified polyvinyl alcohol and other modified polyvinyl alcohols; cellulose derivatives such as hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, ethyl cellulose and acetyl cellulose; styrene-maleic anhydride copolymer, styrene-butadiene Copolymer, polyvinyl chloride, polyvinyl acetate, polyacrylamide, polyacrylic acid ester, polyacrylic acid ester, polyvinyl chloride Butyral, polystyrene,
And synthetic polymers such as copolymers composed of combinations thereof; polyamide resins, silicone resins, petroleum resins,
Resins such as terpene resin, ketone resin and coumarone resin can be exemplified. Among these examples, polyvinyl alcohol-based binder has dispersibility, binder property,
It is also desirable in terms of heat stability of the ground color. These binders should be dissolved in a solvent such as water, alcohol, ketone, ester, hydrocarbon, or emulsified in water or other medium, or used in the form of paste to be used together depending on the required quality. Is also possible.

The fillers used in the present invention include silica, calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, talc, zinc oxide, titanium oxide, zinc hydroxide, aluminum hydroxide, and other inorganic fillers, or polystyrene-based organic fillers. Examples include fillers, styrene / butadiene organic fillers, styrene / acrylic organic fillers, hollow organic fillers, and the like.

In addition to the above, a release agent such as a fatty acid metal salt,
Lubricants such as waxes, UV absorbers such as benzophenone and benzotriazole, water resistant agents such as glyoxal, dispersants, and defoaming agents can also be used.

In the heat-sensitive recording material of the present invention, the blending amount of (a) the dye precursor and (b) the bisurea compound (or its zinc derivative), the type of other various components, and the blending amount are required. It is determined according to the properties (for example, background color heat resistance and recording suitability) and is not particularly limited, but usually 1 to 8 parts of the bisurea compound (or its zinc derivative) to 1 part of the dye precursor. The filler is 1 to 20 parts, and the binder is 10 to 25 in the total solid content.
% By weight. These materials are pulverized by a crusher such as a ball mill, attritor, or sand grinder, or an appropriate emulsifying device to a particle size of several microns or less, and a binder and various additives depending on the purpose are added to a coating liquid. And A desired thermosensitive recording medium can be obtained by applying the coating liquid to a support.

Examples of the support used in the heat-sensitive recording material of the present invention include paper, synthetic paper, non-woven fabric, metal foil, plastic film, plastic sheet, or a composite sheet obtained by combining these.

The heat-sensitive recording material of the present invention is provided with an overcoat layer made of a polymer material on the heat-sensitive color forming layer for the purpose of enhancing the storage stability of the recording material, or contains a filler for the purpose of enhancing the color developing sensitivity of the recording material. An undercoat layer of the above-mentioned polymer substance or the like can be provided below the thermosensitive color developing layer.

The thermosensitive recording medium of the present invention utilizes high ground color stability to thermally laminate a plastic film,
A transparent and strong protective coating can be provided. For example,
Even after heat-sensitive recording on the heat-sensitive recording material of the present invention, a card having excellent stability such as heat resistance can be easily prepared using a commercially available simple laminating machine. Examples of the plastic film used in the heat-sensitive recording material of the present invention include low density polyethylene, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, ethylene / methyl methacrylate copolymer, ethylene / methacrylic acid copolymer. Thermoplastic resins such as coalesced can be mentioned.

Further, the heat-sensitive recording material of the present invention may contain a light absorber which absorbs light and converts it into heat in the heat-sensitive recording layer. The light absorber is not particularly limited as long as it is a substance that absorbs the emission wavelength of various light sources.

For example, when a light source having a continuous wavelength, a strobe flash, or the like is used as a light source for recording, the light absorber described in JP-A-2-206583 and Japanese Patent Application No. 5-30954 is used. Examples include heating reaction products of thiourea derivatives / copper compounds, graphite described in JP-A-3-86580, copper sulfide, lead sulfide, molybdenum trisulfide, black titanium, carbon black, and the like.

On the other hand, when a semiconductor laser is used as a light source for recording, it is used as a light absorber in JP-A-54-4142.
JP-A-58-94494, JP-A-58-209594, JP-A-2-217287, JP-A-3-73814, etc., polymethine dyes (cyanine dyes),
Azolenium dyes, pyrylium dyes, thiopyrylium dyes, squarylium dyes, croconium dyes, dithiol complexes, mercaptophenol metal complex dyes, mercaptonaphthol metal complex dyes, phthalocyanine dyes, naphthalocyanine dyes, triarylmethane dyes Examples thereof include dyes, immonium dyes, diimmonium dyes, naphthoquinone dyes, anthraquinone dyes, and metal complex dyes. Further, the light absorbers mentioned in the case of the light source having a continuous wavelength can be used as well.

Specifically, for example, Color Chemical Encyclopedia (edited by the Organic Synthesis Society, CMC Publishing (1988) p196-2)
00) Table 1 and Chemical Industry (vol.5, 1986, p379-389) Table 3
Near infrared absorbing dyes described, JP-A-61-69991, JP-A-61-69991
61-246391 Publication, US-PATENT: 35570122, US-PATENT: 35
75871, near-infrared absorbing dyes described in US-PATENT: 3637769, 1,1,5,5-tetrakis (p-dimethylaminophenyl)
-3-Methoxy-1,4-pentadiene (or its cation), 1,1,5,5-tetrakis (p-diethylaminophenyl) -3-methoxy-1,4-pentadiene (or its cation), toluene Dithiol nickel complex, 4-tert
-Butyl-1,2-benzenedithiol nickel complex, bisdithiobenzyl nickel complex, bis (4-ethyldithiobenzyl) nickel complex, bis (4-n-propyldithiobenzyl) nickel complex and the like. You may use these light absorbers individually or in mixture of 2 or more types.

These light absorbing agents are used (a) by simply mixing them in various materials required for a thermosensitive recording medium, and (b)
As described in 2-217287, etc., in various materials necessary for a thermal recording material, a method in which a light absorber is melt-mixed in advance and dissolved or dispersed, or (c)
The light absorber may be dissolved or dispersed in a solvent in advance in various materials necessary for the heat-sensitive recording material, and the dissolved or dispersed mixture may be used according to a method of using after removing the solvent. Further, the light absorber is a developer, a dye precursor,
It may be co-dispersed (simultaneous mixing dispersion) with a sensitizer, a mixture of a developer and a sensitizer, or a mixture of a dye precursor and a sensitizer.

The heat-sensitive recording material of the present invention does not change its background color stability (heat resistance, solvent resistance, etc.) even if it contains a light absorber. Therefore, even in the case of a heat-sensitive recording material containing a light absorber, toner recording,
Alternatively, heat lamination or the like can be performed.

A heat-sensitive recording medium prepared by heat-laminating a heat-sensitive recording material containing a light absorber with a plastic film before or after heat-sensitive recording is to be recorded with light from above the laminated plastic film. You can also

[0063]

The bisurea compound of the present invention is excellent in color developability,
It is also a developer that has excellent background color heat resistance and background color solvent resistance. Further, it is also excellent in color developability as compared with a bisurea compound having no carboxyl group or hydroxyl group. Furthermore, the zinc derivative of the bisurea compound of the present invention is more excellent in color developability. The clear reason why the bisurea compound of the present invention imparts high ground color stability has not yet been elucidated. However, as one of the reasons, the following is presumed.

The bisurea compound of the present invention has a carboxyl group and a carboxyl group of an arylureido structure having a carboxyl group and a hydroxyl group, and a carboxyl group as sites that are considered to have a color developing property (a property of developing a dye precursor). There are three urea structures of arylureido structure. However, among the three, the urea structure is considered to be mainly involved in color development. This urea structure is
The structure changes according to the conditions as shown in the following equation. Since this change is a phenomenon similar to keto / enol tautomerism, it is referred to as keto or enol here for convenience.

[0065]

Embedded image

In order for the urea structure to function as a color developer, it seems necessary to be enolized. The enolization requires high temperature conditions. Since the thermal head momentarily reaches a high temperature of 200 to 300 ° C, it is considered that the urea structure causes enolization and develops color by contact with the thermal head. Therefore, under temperature conditions below the temperature at which enolization occurs, the urea structure retains the keto type and does not develop color, so that the ground color is stable. This seems to be the reason why the ground color heat resistance is high.

On the other hand, the carboxyl group and the hydroxyl group are
Rather than being directly involved in color development, it seems to act as an acid catalyst for the enolization of the urea structure. The carboxyl group and the hydroxyl group are, for example,
It seems to be greatly useful for lowering the enolization temperature and improving the enolization rate (the conversion ratio from keto type to enol type), and therefore, compared to the case where no carboxyl group and hydroxyl group are present, It is considered that a heat-sensitive recording material excellent in recording density can be obtained.

Further, the ground color does not change due to the writing of the oil-based ink because the bisurea compound of the present invention has a low solubility in the solvent used in the oil-based ink, and even if it is brought into contact with these solvents, it does not react with the dye precursor. It is considered that this is because there is substantially no mixing with the developer.

[0069]

【Example】

<Synthesis of Bisurea Compound> As a synthesis example of a bisurea compound, synthesis examples of compounds A-4 and A-5 are shown below. Other than these, the synthesis of the bisurea compound was performed in Synthesis Example 1
It was carried out according to ~ 2.

Synthesis Example 1 5-Amino-2-hydroxybenzoic acid (16.5 g, 110 mM) was dissolved in acetone (200 ml). Add hexamethylene diisocyanate (8.4 g, 50 m
A solution of M) in ethyl acetate (100 ml) was added dropwise. 6
Upon stirring at 0 ° C for 1 hour, a precipitate was formed. This was filtered and thoroughly washed with acetone and n-hexane until one spot was obtained on TLC (thin layer chromatography).
I got A-4.

[Synthesis Example 2] 4-amino-2-hydroxybenzoic acid (16.5 g, 110 mM) was dissolved in ethyl acetate (200 ml).
Hexamethylene diisocyanate (8.4 g, 50
A solution of mM) in ethyl acetate (50 ml) was added dropwise. 60
Precipitation occurred after stirring for 1.5 hours at ℃. Filter this,
The compound A-5 was sufficiently washed with ethyl acetate and n-hexane until 1 spot on TLC was obtained.

<Production of Thermosensitive Recording Body> In the following description, parts and% indicate parts by weight and% by weight, respectively. [Examples 1 to 20] The urea compound of the present invention, or a zinc derivative thereof, as a developer and as a dye precursor,
A thermosensitive recording medium was produced using any of the six types of dye precursors shown below. (See Tables 1 and 2) ODB: 3-diethylamino-6-methyl-7-anilinofluorane ODB-2: 3-dibutylamino-6-methyl-7-anilinofluorane TH-107: 3-dibutyl Amino-7- (o-chloroanilino) fluorane CVL: 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide New Blue: 3- (4-diethylamino-2-ethoxyphenyl) -3- ( 1-ethyl-2-methylindol-3-yl) -4-
Azaphthalide I-Red: 3,3-bis (1-ethyl-2-methylindole-3-
That is, first, the color developer dispersion (solution A) and the dye precursor dispersion (solution B) having the following compositions were ground to an average particle size of 1 micron with a sand grinder. (Liquid A: Developer Dispersion) Urea compound of the present invention or its zinc derivative 6.0 parts 10% Polyvinyl alcohol aqueous solution 18.8 parts Water 11.2 parts (Liquid B: dye precursor dispersion) Each dye precursor 2.0 parts 10% Aqueous polyvinyl alcohol solution 4.6 parts Water 2.6 parts Next, liquid A (developing agent dispersion liquid), liquid B (dye precursor dispersion liquid), and kaolin clay dispersion liquid were mixed at the following ratio to prepare a coating liquid. Solution A: Developer dispersion 36.0 parts Solution B: Dye precursor dispersion 9.2 parts Kaolin clay (50% dispersion) 12.0 parts Coating solution 6.0 g / m ² on one side of 50 g / m ² base paper
It is coated and dried so that it has a surface area of m ² , and this sheet is treated with a super calendar so that the smoothness is 500 to 600 seconds.
A thermosensitive recording medium was prepared.

[Comparative Examples 1 to 8] The following compounds were used as developers in the same manner as in Examples 1 to 20 to prepare thermal recording materials for Comparative Examples. (See Table 1) (Developer compound for comparative example) Bisphenol A (B-1) Bisphenol S (B-2) 4-hydroxy-4'-iso-propoxydiphenyl sulfone (B-3) 4-hydroxy- 4'-n-butyroxydiphenyl sulfone (B
-4) Phenylurea (B-5) JP-A-58-211496 JP Bisurea compound (B-6) JP-A-5-147357 JP Bisurea compound (B-7) That is, the following formulation The dispersion liquid of each developer compound shown in 1 was ground to an average particle size of 1 micron with a sand grinder. (C liquid: developer dispersion liquid) Developer compound (B-1 to B-7) 6.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts water 11.2 parts Next, at the following ratio, liquid C (developing agent dispersion liquid) ), A dye precursor (ODB or CVL) dispersion (solution B), and a kaolin clay dispersion were mixed to prepare a coating solution. Liquid C: Developer dispersion 36.0 parts Liquid B: Dye precursor dispersion 9.2 parts Kaolin clay (50% dispersion) 12.0 parts Coating solution 6.0g / on one side of 50g / m ² base paper
It is coated and dried so that it has a surface area of m ² , and this sheet is treated with a super calendar so that the smoothness is 500 to 600 seconds.
A thermosensitive recording medium was prepared.

[0074]

[Chemical 17]

<Evaluation of Thermal Recording Material> The thermal recording material thus obtained was subjected to a recording test by a word processor, a thermal stability test for the background color, and an oil ink suitability test. The evaluation results of Examples 1 to 20 and Comparative Examples 1 to 8 are shown in Tables 1 and 2.

[Recordability test (dynamic color density)]: A word processor (trade name: RUPO
-90F / manufactured by Toshiba Co., Ltd.) was used and recording was performed on the prepared thermal recording medium under the maximum applied energy condition. Then
The Macbeth value of the recording part was calculated using the Macbeth densitometer (RD-914,
An amber filter was used. Hereinafter, the concentration measurement was performed under these conditions. ). In this case, the larger the Macbeth value, the higher the recording density and the better the recording suitability. When ODB was used as the dye precursor, the Macbeth value was 0.
8 or more is "recordability is good", and
A Macbeth value of 1.20 or more was judged to be “excellent in recordability”.

[Heat resistance test (static color density)]: In order to check the heat resistance of the recording material to the ground color, a hot plate heated to 90 ° C., 120 ° C. and 135 ° C. was applied at a pressure of 10 g / cm ² . The prepared thermal recording material was pressed for 4 seconds, and the recording material was measured with a Macbeth densitometer. In this case, the smaller the Macbeth value,
The ground color is less colored and the heat resistance of the ground color is high.

[Oil-based ink suitability test (ground-color discoloration test with oil-based ink)]: Written on a thermosensitive recording medium prepared with an oil-based red magic ink (trade name: Magic INK No. 500 / manufactured by Teranishi Kagaku Co., Ltd.) Then, the degree of discoloration with respect to the original red color was visually measured. ◎ ... No discoloration ○ ... Almost no discoloration △ ... Slightly discolored × ... Remarkably discolored

[0079]

[Table 1]

[Table 2]

[Embodiment 21] A thermal recording material of Embodiment 1 is sandwiched between pouch films and a simple laminating apparatus (trade name: M
Thermal lamination was carried out using S Pouch H-140 / Meiko Shokai Co., Ltd. When the recorded part and the background color part were measured with a Macbeth densitometer, the recorded part was 1.41 and the background color part was 0.13.

[Embodiment 22] A heat-sensitive recording material of Embodiment 12 is sandwiched between pouch films and a simple laminating apparatus (trade name: M
Thermal lamination was carried out using S Pouch H-140 / Meiko Shokai Co., Ltd. When the recording part and the background color part were measured with a Macbeth densitometer, the recording part was 1.35 and the background color part was 0.14.

[Embodiment 23] In the thermal recording material of Embodiment 3, a copying machine (trade name: NP6060 / manufactured by Canon Inc.)
Then, when toner recording was performed, no change was observed in the background color, and printing could be performed.

[Example 24] In the thermal recording material of Example 17, a copying machine (trade name: NP6060 / manufactured by Canon Inc.)
Then, when toner recording was performed, no change was observed in the background color, and printing could be performed.

<Production of Optical Recording Material> [Examples 25 to 26] ODB was prepared using Compound A-4 as a developer.
Was used as a dye precursor, and as a light absorber, an optical recording material was prepared by using a hot melt of an absorbing dye and a sensitizer. Cyanine dye (trade name: NK-2015 / manufactured by Japan Photosensitive Dye Research Institute) Immonium dye (trade name: IRG-002 / manufactured by Nippon Kayaku Co., Ltd.) That is, first, 4-biphenyl-p- To 94 parts of trilyl ether, 6 parts of an absorption dye was added, heated to 100 to 150 ° C., melt-mixed and then pulverized to obtain a light absorber. Then, the light absorbent dispersion having the following composition was ground to an average particle size of 1 micron with a sand grinder. (Liquid D: Light Absorber Dispersion) Light Absorber 4.0 parts 10% Polyvinyl alcohol aqueous solution 10.0 parts Water 6.0 parts Next, a dispersion liquid of compound A-4 (A
Liquid), the dispersion liquid of the dye precursor (ODB) (liquid B), the liquid D (light absorbent dispersion liquid), and the dispersion liquid of kaolin clay were mixed to prepare a coating liquid. Liquid A (developer dispersion liquid) 36.0 parts Liquid B (dye precursor dispersion liquid) 9.2 parts Liquid D (light absorber dispersion liquid) 20.0 parts Kaolin clay (50% dispersion liquid) 12.0 parts This coating liquid 50 g / m Coating amount 6.0g / on one side of base paper ²
It is coated and dried so that it has a surface area of m ² , and this sheet is treated with a super calendar so that the smoothness is 500 to 600 seconds.
A thermosensitive recording medium was prepared.

[Examples 27 to 28] As a light absorber, a heat-sensitive recording material was produced by using an absorbing dye alone instead of a thermal melt of an absorbing dye and a sensitizer. Toluenedithiol nickel complex (TDNi) 1,1,5,5-tetrakis (p-diethylaminophenyl) -3-
Methoxy-1,4-pentadiene (TDEPMP) The following light-absorbing developer dispersion liquid (E liquid) was ground with a sand grinder to an average particle size of 1 micron. (Solution E: light absorbing developer dispersion) Compound A-4 6.0 parts TDNi or TDEPMP 1.0 part 10% polyvinyl alcohol aqueous solution 18.8 parts water 10.2 parts Then, at the following ratio, the light absorbing developer dispersion (E
Liquid), a dispersion liquid of the dye precursor (ODB) used in Example 2 (liquid B), and a dispersion liquid of kaolin clay were mixed to prepare a coating liquid. Liquid E (light-absorbing developer dispersion) 36.0 parts Liquid B (dye precursor dispersion) 9.2 parts Kaolin clay (50% dispersion) 12.0 parts This coating solution is applied to one side of a 50 g / m ² base paper. Quantity 6.0g /
It is coated and dried so that it has a surface area of m ² , and this sheet is treated with a super calendar so that the smoothness is 500 to 600 seconds.
A thermosensitive recording medium was prepared.

<Evaluation of Thermal Recording Material Containing Light Absorber>
A recording test was performed on the obtained thermal recording material.
The evaluation results are shown in Table 3. [Recordability test (optical recording)]: A laser plotter device described in JP-A-3-239598 was used to irradiate an optical recording medium with laser light, and the recording portion was measured with a Macbeth densitometer. As the light irradiation conditions, a semiconductor laser (product name: LT015MD / Sharp Co., Ltd.) with an oscillation wavelength of 830 nm and an output of 30 mW was used as a recording light source, and a light collecting lens with a numerical aperture of 0.45 and a focal length of 4.5 mm Using a spherical plastic lens (trade name: AP4545 / manufactured by Konica Corp.) at a recording speed of 50 mm / sec and a recording interval of 50 microns,
Solid prints of 1 cm in length and width were obtained.

[0087]

[Table 3]

[0088]

INDUSTRIAL APPLICABILITY As described above, the bisurea compound of the present invention has a stable background color under environmental conditions in the range of 120 ° C. to 135 ° C., but is more effective than a thermal head. It is possible to obtain a record of recording density. The effects of the present invention include, for example, the following points.

(1) The heat-sensitive recording material of the present invention is a heat-sensitive recording material having excellent background color stability such as heat resistance and solvent resistance as compared with the conventional heat-sensitive recording material. (2) The thermal recording material of the present invention can be used under severe environmental conditions (for example, temperature conditions in the range of 90 ° C to 135 ° C). (3) The thermosensitive recording medium of the present invention can be freely written on the recording surface (the surface having the thermosensitive coloring layer) using an oil-based ink. (4) The thermosensitive recording medium of the present invention can be heat laminated with a plastic film by a simple laminating device or the like. Therefore, a card or the like can be easily made. (5) The heat-sensitive recording material of the present invention can be used for toner recording. Further, particularly when pursuing the recording sensitivity, it is possible to improve the sensitivity by using the zinc derivative of the bisurea compound of the present invention. This zinc derivative is also believed to be useful as a developer for pressure sensitive paper. Similar effects can be expected even if the thermal recording medium of the present invention contains a light absorbing agent.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisami Satake 5-21-1 Oji, Kita-ku, Tokyo Inside Nippon Paper Industries Co., Ltd.

Claims (5)

[Claims] 1. A thermosensitive recording medium having a thermosensitive color developing layer comprising a colorless or light-colored dye precursor and a developer which reacts when heated to develop the color of the dye precursor, wherein the developer has the following general formula: A thermosensitive recording material represented by (1), wherein the thermosensitive coloring layer contains at least one kind of the bisurea compound. Embedded image (Here, X represents an alkyl group having 1 to 6 carbon atoms, a halogen atom, or a hydrogen atom. A represents a divalent group having 30 or less carbon atoms.) 2. The heat-sensitive recording material according to claim 1, wherein the developer is a bisurea compound represented by the following general formula (2). Embedded image (Here, X represents an alkyl group having 1 to 6 carbon atoms, a halogen atom, or a hydrogen atom. Further, n is 1 to 12
Represents the integer. ) 3. A thermosensitive recording material having a thermosensitive color developing layer comprising a colorless or light-colored dye precursor and a developer which reacts when heated to develop the color of the dye precursor, wherein the developer has the following general formula: A heat-sensitive recording material, which is a zinc derivative of a bis-urea compound represented by (3), wherein the heat-sensitive color developing layer contains at least one kind of the bis-urea compound. Embedded image (Here, X represents an alkyl group having 1 to 6 carbon atoms, a halogen atom, or a hydrogen atom. A represents a divalent group having 30 or less carbon atoms.) 4. The claim 1, claim 2, or claim 3.
A thermosensitive recording card obtained by laminating the thermosensitive recording medium described above with a plastic film. 5. The claim 1, claim 2, or claim 3.
A transfer sheet for electrophotography, which uses the thermosensitive recording medium described.