JPH1128869A - Heat-sensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve oil resistance and plasticizer resistance of a color- developed image without spoiling other performance of a heat-sensitive recording material by laminating a heat-sensitive recording layer contg. a specified fluoran compd. as a color developing agent and a specified ureide compd. as a developer on a substrate. SOLUTION: A heat-sensitive recording layer contg. at least one fluoran compd. of formula I (wherein R1 and R2 are each an independent 1-5C alkyl group) as a color developing agent and at least one ureide compd. of formula II (wherein R3 is a structural unit of formula III, etc.), as a developer is laminated to form a heat-sensitive recording material. As practical examples of the fluoran compd., 2-(3-methylanilino)-3-methyl-6-dimethylaminofluoran, etc., are cited and as practical examples of the ureide compd., 4,4'-bis(p- toluenesulfonylamino-carbonylamino)diphenylmethane, etc., are cited.

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, and more particularly to a heat-sensitive recording material having excellent storage stability such as oil resistance and plasticizer resistance of a color image.

[0002]

2. Description of the Related Art In general, a heat-sensitive recording material is provided on a support such as paper, synthetic paper, plastic film or the like, with an electron-donating color former (hereinafter referred to as a color former) and an organic or inorganic electron-accepting developer (hereinafter referred to as a color developer). , A color developer) as a main component, by applying thermal energy to a thermosensitive coloring layer to obtain a recorded image. Such a heat-sensitive recording material is disclosed in
No. 4,160, JP-B-45-14039 and JP-A-48-27736 are widely used.

[0003] Thermal recording materials are compact, inexpensive, and easy to maintain, so that the output of electronic computers, facsimile machines, automatic ticket vending machines, printers for scientific measuring instruments, printers for CRT medical measurement, etc. Used for a wide range of applications.

However, in the case of a leuco dye-type heat-sensitive recording material having a heat-sensitive color-developing layer containing a color former, a color developer and a binder as active components on a support, the color development reaction is reversible. Therefore, it is known that a color image fades with time. Further, the fading is accelerated in an atmosphere of light exposure, high humidity, and high temperature, and proceeds rapidly due to contact with a plasticizer, oil, or the like, and the color image fades to an unreadable level.

[0005] Various attempts have been made to solve this problem. For example, JP-A-62-121769 discloses a method of using a dimer type fluoran dye as a color former.
A method in which a metal salt of a specific salicylic acid derivative is used as a color developer, and JP-A-3-38996 discloses that 1,3-diimino-4,5,6,7-tetrachloroisoindoline and 4,4 ', 4 " -A method utilizing an irreversible reaction with triisocyanato-2,5-dimethoxytriphenylamine and the like are disclosed.

[0006] Those using a fluoran dye of the dimer type have improved storage stability of the color former, but have the disadvantage that the background (uncolored portion) whiteness and color sensitivity are reduced.

A thermosensitive recording material utilizing an irreversible reaction between a diiminoisoindoline derivative and a triisocyanate has a robust color-developing portion, but develops red when an uncolored portion comes in contact with a plasticizer, resulting in poor quality. It has the disadvantage of being severely impaired.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material which has improved oil resistance and plasticizer resistance, particularly of a color image, without impairing other properties as a heat-sensitive recording material. is there.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, at least one fluoran compound represented by the general formula (1) as a color former has been developed. The inventors have found that the problem can be solved by a heat-sensitive recording material using at least one ureide compound represented by the general formula (2) as a coloring agent, and have completed the present invention.

[0010]

Embedded image [Wherein, R ₁ and R ₂ each independently represent a carbon atom of 1
5 to 5 alkyl groups. ]

[0011]

Embedded image

Wherein R ₃ is

Embedded image Is shown. ]

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the fluoran compound represented by the general formula (1), R ₁ and R ₂ are methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl. Group, isobutyl group, n-pentyl group and isopentyl group, and among them, those having 2 to 5 carbon atoms are particularly preferable.

A specific example of the fluoran compound represented by the general formula (1) is 2- (3-methylanilino) -3-
Methyl-6-dimethylaminofluoran, 2- (3-methylanilino) -3-methyl-6-diethylaminofluoran, 2- (3-methylanilino) -3-methyl-6
-Di-n-propylaminofluoran, 2- (3-methylanilino) -3-methyl-6-diisopropylaminofluoran, 2- (3-methylanilino) -3-methyl-6-di-n-butylaminofluoran Oran, 2- (3-methylanilino) -3-methyl-6-diisobutylaminofluoran, 2- (3-methylanilino) -3-methyl-6- (N-methyl-N-isobutylamino) fluoran, 2- ( 3-methylanilino) -3-methyl-6-
(N-ethyl-N-propylamino) 2- (3-methylanilino) -3-methyl-6- (N-ethyl-N-isopentylamino) fluoran, 2- (3-methylanilino) -3-methyl-6 -Di-n-pentylaminofluoran and the like.

Particularly preferred are 2- (3-methylanilino) -3-methyl-6-diethylaminofluoran and 2- (3-methylanilino) -3-methyl-6-di-n-butylaminofluoran, especially Cu Diffraction angle (2θ) in powder X-ray diffraction by Kα ray: 7.6 °, 1
2.2 °, 14.9 °, 15.9 °, 17.6 °, 2
Preferred is the β-crystal modification of 2- (3-methylanilino) -3-methyl-6-diethylaminofluoran, characterized by 2.8 °.

The fluoran compound represented by the general formula (1) can be produced, for example, by the following method.

General formula (3)

Embedded image [Wherein, R ₁ and R ₂ are the same as defined above. A benzophenone compound represented by the general formula (4):

[0018]

Embedded image [Wherein, R represents a hydrogen atom or a lower alkyl group. ]
Is reacted at a temperature of 0 to 50 ° C. for several hours to several tens of hours in the presence of a dehydration condensing agent such as concentrated sulfuric acid, and the resulting reaction product is treated with an aqueous alkali solution such as sodium hydroxide. After that, the fluoran compound represented by the general formula (1) can be obtained in the form of a white to slightly colored powder by performing purification, recrystallization, and the like using an appropriate organic solvent as necessary. .

Also, 2- (3-methylanilino) -3-
The β-crystal modification of methyl-6-diethylaminofluoran can be obtained according to the method disclosed in JP-A-6-25249. For example, the benzophenone compound of the general formula (3) is reacted with the diphenylamine compound of the general formula (4) in the presence of a dehydrating condensing agent, and then impurities in an organic solvent extract of the treated product after alkali treatment are extracted. It can be produced by precipitating from an organic solvent extract that is 10% or less of the components.

As the developer represented by the general formula (2),
Specifically, 4,4′-bis (p-toluenesulfonylaminocarbonylamino) diphenylmethane, 4,4 ′
-Bis (p-toluenesulfonylaminocarbonylamino) diphenyl sulfide, 3,4'-bis (p-toluenesulfonylaminocarbonylamino) diphenyl ether, 4,4'-bis (p-toluenesulfonylaminocarbonylamino) diphenyl ether, 2-bis [4- (p-toluenesulfonylaminocarbonylamino) phenyl] ethane, 2,8 dimethyl-3,7-
(P-toluenesulfonylaminocarbonylamino) dibenzothiophene-5,5-dioxide and 1,3-
Bis [4- (p-toluenesulfonylaminocarbonylamino) phenoxy] benzene is exemplified.

The ureide compound represented by the general formula (2) can be produced, for example, by the following method. p
An alkali metal salt of toluenesulfonic acid and a compound represented by the general formula (5)

Embedded image [Wherein, R represents the same as R described above. With a diisocyanate compound represented by the formula (1) in a polar solvent and subjecting the obtained dialkali salt of the diureide compound to dealkalization using a mineral acid.

In the present invention, other coloring agents can be used in combination as long as the effect is not impaired. As the color former that can be used in combination, any of those conventionally used for this type of recording material can be used. In particular, fluoran, diarylphthalide, indolylphthalide, vinylogphthalide, azaphthalide, diarylmethane, rhodamine lactam, thiazine, spiropyran and fluorene colorants are preferred.

Examples of some of these are fluoran compounds such as 3,6-dimethoxyfluoran,
Chloro-6-cyclohexylaminofluoran, 3-chloro-6-cyclohexylaminofluoran, 2-methyl-6-cyclohexylaminofluoran, 3-methyl-6-cyclohexylaminofluoran, 1,3-dimethyl-6 Diethylaminofluoran, 2-tert-
Butyl-6-diethylaminofluoran, 2-chloro-
6-diethylaminofluoran, 2-chloro-3-methyl-6-diethylaminofluoran, 2-methyl-6
(N-ethyl-4-methylanilino) fluoran, 8-
Diethylaminobenzo [a] fluoran, 2-dibenzylamino-6-diethylaminofluoran, 2-dibenzylamino-4-methyl-6-diethylaminofluoran, 2-n-octylamino-6-diethylaminofluoran, 2- Anilino-6- (N-ethyl-NNn-hexylamino) fluoran, 2- (N-methylanilino) -6- (N-ethyl-4-methylanilino) fluoran, 2-chloro-3-methyl-6- [ 4- (4-anilinoanilino) anilino] fluoran, 2-anilino-
3-methyl-6-dimethylaminofluoran, 2-anilino-3-methyl-6-diethylaminofluoran, 2
-Anilino-3-methyl-6-di-n-propylaminofluoran, 2-anilino-3-methyl-6-di-n-
Butylaminofluoran, 2-anilino-3-methyl-
6-di-n-pentylaminofluoran, 2-anilino-3-methyl-6- (N-methyl-N-ethylamino)
Fluoran, 2-anilino-3-methyl-6- (N-methyl-NN-propylamino) fluoran, 2-anilino-3-methyl-6- (N-methyl-N-n-butylamino) fluoran,

2-anilino-3-methyl-6- (N-methyl-N-isobutylamino) fluoran, 2-anilino-3-methyl-6- (N-methyl-NNn-pentylamino) fluoran, -Anilino-3-methyl-6-
(N-methyl-N-cyclohexylamino) fluoran, 2-anilino-3-methyl-6- (N-ethyl-N
-N-propylamino) fluoran, 2-anilino-3
-Methyl-6- (N-ethyl-NN-butylamino)
Fluoran, 2-anilino-3-methyl-6- (N-ethyl-N-isobutylamino) fluoran, 2-anilino-3-methyl-6- (N-ethyl-Nn-pentylamino) fluoran, 2- Anilino-3-methyl-6
(N-ethyl-N-isopentylamino) fluoran,
2-anilino-3-methyl-6- (N-ethyl-Nn
-Octylamino) fluoran, 2-anilino-3-methyl-6- [N-ethyl-N- (3-ethoxypropyl) amino] fluoran, 2-anilino-3-methyl-
6- (N-ethyl-Np-tolylamino) fluoran, 2-anilino-3-chloro-6-diethylaminofluoran, 2-anilino-3-chloro-6-di-n-butylaminofluoran,

2- (2-chloroanilino) -6-diethylaminofluoran, 2- (2-chloroanilino) -6
-Di-n-butylaminofluoran, 2- (2-fluoroanilino) -6-diethylaminofluoran, 2-
(2-fluoroanilino) -6-di-n-butylaminofluoran, 2- (3-trifluoromethylanilino)
-6-dimethylaminofluoran, 2- (3-trifluoromethylanilino) -6-diethylaminofluoran, 2- (3-trifluoromethylanilino) -6-di-n-butylaminofluoran, 2 -(4-methylanilino) -3-methyl-6-diethylaminofluoran,
2- (4-t-amylanilino) -3-methyl-6-diethylaminofluoran, 2- (3-chloro-4-methylanilino) -3-methyl-6-diethylaminofluoran, 2- (2,4-dimethyl Anilino) -3-methyl-6-diethylaminofluoran, 2- (2,4-dimethylanilino) -3-methyl-6-di-n-butylaminofluoran, 2- (2,6-dimethylani Reno) -3
-Methyl-6-diethylaminofluoran, 2- (2,
6-dimethylanilino) -3-methyl-6-di-n-butylaminofluoran, 2- (2,6-diethylanilino) -3-methyl-6-diethylaminofluoran, 2
-(2,6-diethylanilino) -3-methyl-6-di-n-butylaminofluoran, 2-anilino-3-methoxy-6-diethylaminofluoran, 2,2-bis {4- [6 -(N-cyclohexyl-N-methylamino) -3-methylfluoran-2-ylamino] phenyl} propane and the like,

As the diarylphthalide compound,
3,3-bis (4-dimethylaminophenyl) -6-dimethylaminophthalide (general name: CVL), 3,3-bis (4-dimethylaminophenyl) phthalide, 3- (4-
Dimethylaminophenyl) -3- (4-diethylamino-2-methylphenyl) -6-dimethylaminophthalide, 3,3-bis (9-ethylcarbazol-3-yl) -6-dimethylaminophthalide, 3- (4-dimethylaminophenyl) -3- (1-methylpyrrole-3-
Yl) -6-dimethylaminophthalide and the like,

As the indolylphthalide compound, 3
-(4-dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl) phthalide, 3,3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,3-bis (1-ethyl-2-
Methylindol-3-yl) phthalide, 3,3-bis (1-n-butyl-2-methylindol-3-yl)
Phthalide, 3,3-bis (1-n-octyl-2-methylindol-3-yl) phthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-methylindole- 3-yl) phthalide, 3-
(2-ethoxy-4-dibutylaminophenyl) -3-
(1-ethyl-2-methylindole-3-yl) phthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-octyl-2-methylindole-3
-Yl) phthalide, etc.

As vinylogous phthalide compounds, 3
-(4-Diethylaminophenyl) -3- [2,2-bis (1-ethyl-2-methylindol-3-yl) ethenyl] phthalide, 3,3-bis [2- (4-dimethylaminophenyl)- 2- (4-methoxyphenyl) ethenyl] -4,5,6,7-tetrachlorophthalide, 3,
3-bis [2- (4-pyrrolidinophenyl) -2- (4
-Methoxyphenyl) ethenyl] -4,5,6,7-tetrachlorophthalide, 3,3-bis [2,2-bis (4
-Dimethylaminophenyl) ethenyl] -4,5,6
7-tetrachlorophthalide, 3,3-bis [2,2-bis (4-pyrrolidinophenyl) ethenyl] -4,5
6,7-tetrabromophthalide and the like,

The azaphthalide compounds include 3,3-
Bis (4-diethylamino-2-ethoxyphenyl)-
4-azaphthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- [4- (N-ethyl-N-phenylamino) -2-ethoxyphenyl] -4-azaphthalide, 3- (4-diethylamino- 2-ethoxyphenyl) -3- (1-ethyl-2-methylindole-3-
Yl) -4-azaphthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-n-octyl-
2-methylindol-3-yl) -4-azaphthalide and the like,

As the diarylmethane compound, 4,
4′-bis (dimethylamino) benzhydryl benzyl ether, N-halophenylleuco auramine, etc.
Rhodamine lactam compounds include rhodamine B anilino lactam and rhodamine B (4-nitroanilino)
Lactam, rhodamine B (4-chloroanilino) lactam and the like,

Examples of the thiazine compound include benzoyl leucomethylene blue and p-nitrobenzoyl leucomethylene blue, and examples of the spiropyran compound include 3-
Methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3-phenylspirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-propylspirodinaphthopyran and the like,

Examples of the fluorene compound include 3,6-bis (dimethylamino) fluorenespiro [9,3 ']-
6'-dimethylaminophthalide, 3-diethylamino-
6- (N-allyl-N-methylamino) fluorenespiro [9,3 ′]-6′-dimethylaminophthalide, 3,
6-bis (dimethylamino) spiro [fluorene-9,
6′-6′H-chromeno (4,3-b) indole],
3,6-bis (dimethylamino) -3′-methylspiro [fluorene-9,6′-6′H-chromeno (4,3-
b) Indole], 3,6-bis (diethylamino)-
3'-methylspiro [fluorene-9,6'-6'H-
Chromeno (4,3-b) indole] and the like.
These may be used alone or in combination of two or more.

As with the color former, the developer is also
Other developers may be used in combination as long as the effects of the present invention are not impaired, and additives and fillers may be added.

Examples of the developer which can be used in combination include phenol derivatives, organic acids or metal salts / complexes, urea derivatives and the like.

Examples of some of these developers include 4-tert-butylphenol and phenol derivatives as phenol derivatives.
4-octylphenol, 4-phenylphenol, 1
-Naphthol, 2-naphthol, hydroquinone, resorcinol, 4-tert-octylcatechol, 2,
2′-dihydroxybiphenyl, 4,4′-dihydroxydiphenyl ether, 2,2-bis (4-hydroxyphenyl) propane [generic name bisphenol A], tetrabromobisphenol A, 1,1-bis (4-hydroxyphenyl) cyclohexane 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 2,2-bis (4-hydroxy Phenyl) -4-methylpentane, 1,4-bis (4-hydroxycumyl) benzene, 1,3,5-tris (4-
Hydroxycumyl) benzene, 1,1,3-tris (2
-Methyl-4-hydroxy-5-cyclohexylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane,
4,4 ′-(m-phenylenediisopropylidene) bisphenol, 4,4 ′-(p-phenylenediisopropylidene) bisphenol, bis (4-hydroxyphenyl) acetic acid ethyl ester, 4,4-bis (4-hydroxy Phenyl) valeric acid-n-butyl ester, 4-
Hydroxybenzoic acid benzyl ester,

4-hydroxybenzoic acid phenethyl ester, 2,4-dihydroxybenzoic acid-2-phenoxyethyl ester, 4-hydroxyphthalic acid dimethyl ester, gallic acid-n-propyl ester, gallic acid-n-
Octyl ester, gallic acid-n-dodecyl ester,
Gallic acid-n-octadecyl ester, hydroquinone monobenzyl ether, bis (3-methyl-4-hydroxyphenyl) sulfide, bis (2-methyl-4-hydroxyphenyl) sulfide, bis (3-phenyl-
4-hydroxyphenyl) sulfide, bis (3-cyclohexyl-4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfoxide, bis (4
-Hydroxyphenyl) sulfone [generic name bisphenol S], tetrabromobisphenol S, bis (3-
Allyl-4-hydroxyphenyl) sulfone, 2,
4'-dihydroxydiphenylsulfone, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-chlorodiphenylsulfone, 4-hydroxy-4'-n-propoxydiphenylsulfone, 4
-Hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy-4'-n-butoxydiphenylsulfone, 3,4-dihydroxy-4'-methyldiphenylsulfone, 2,4-dihydroxydiphenylsulfone, 2-methoxy-4 '-Hydroxydiphenylsulfone, 2-ethoxy-4'-hydroxydiphenylsulfone, bis (2-hydroxy-5-tert-
Butylphenyl) sulfone, bis (2-hydroxy-
5-chlorophenyl) sulfone, 4-hydroxybenzophenone, 2,4-dihydroxybenzophenone,
1,7-bis (4-hydroxyphenylthio) -3,5
-Dioxaheptane, 1,5-bis (4-hydroxyphenylthio) -3-oxapentane and the like,

As the organic carboxylic acid or its metal salt / complex, salicylic acid, 3-isopropylsalicylic acid,
-Tert-butylsalicylic acid, 3-benzylsalicylic acid,
3-chloro-5- (α-methylbenzyl) salicylic acid,
3-phenyl-5- (α, α-dimethylbenzyl) salicylic acid, 3,5-bis- (α-methylbenzyl) salicylic acid, 4- (3-p-toluenesulfonylpropyloxy) salicylic acid, 5- {4- [ 2- (4-methoxyphenoxy) ethoxy] cumyl salicylic acid, 3-cyclohexylsalicylic acid, 3,5-di-tert-butylsalicylic acid, 3-methyl-5-α-methylbenzylsalicylic acid, 4- [2- (4- Methoxyphenoxy) ethoxy]
Salicylic acid, 2-hydroxy-3-naphthoic acid, 2-hydroxy-6-naphthoic acid, monobenzyl phthalate, monophenyl phthalate, 4-nitrobenzoic acid, 3-nitrobenzoic acid, 2-nitrobenzoic acid, 4-
Organic acids such as chlorobenzoic acid or metal salts thereof (for example, metal salts such as nickel, zinc, aluminum and calcium), zinc thiocyanate antipyrine complex,
Molybdate acetylacetone complex, etc.

As urea derivatives, phenylthiouric acid,
N, N'-diphenylthiourea, N, N'-bis (3-
(Trifluoromethylphenyl) thiourea, 1,4-bis (3-chlorophenyl) thiosemicarbazide and the like.

These can be used alone or in combination of two or more.

As the sensitizer, various heat-fusible substances can be used. Examples of these acid amide compounds include, as acid amide compounds, caproic amide, capric amide, stearic amide, palmitic amide, oleic amide, stearyl uric acid, stearic anilide, etc., as fatty acids or metal salts thereof. stearic acid,
Behenic acid, fatty acids such as palmitic acid or their zinc, aluminum, calcium salts and the like,

As ester compounds, benzyl 4-benzyloxybenzoate, phenyl 2-naphthoate, phenyl 1-hydroxy-2-naphthoate, dibenzyl oxalate, bis (4-oxalate)
Methyl benzyl) ester, bis (4-chlorobenzyl) oxalate, diphenacyl glutarate, bis (4-methylphenyl) carbonate, dibenzyl terephthalate, etc., as hydrocarbon compounds such as 4-benzylbiphenyl, m-terphenyl, fluorene, fluoranthene, 2,6-diisopropylnaphthalene, 3-benzylacenaphthene and the like,

As ether compounds, 2-benzyloxynaphthalene, 2- (4-methylbenzyloxy) naphthalene, 1,4-diethoxynaphthalene, 1,4-dibenzyloxynaphthalene, 1,2-diphenoxyethane, , 2-bis (3-methylphenoxy) ethane, 1
Phenoxy-2- (4-ethylphenoxy) ethane,
1- (4-methoxyphenoxy) -2-phenoxyethane, 1- (4-methoxyphenoxy) -2- (3-methylphenoxy) ethane, 1- (4-methoxyphenoxy) -2- (2-methylphenoxy) Ethane, 4- (4
-Methylphenoxy) biphenyl, 1,4-bis (2-
Chlorobenzyloxy) benzene, 4,4'-di-n-
Butoxydiphenylsulfone, 1,2-diphenoxybenzene, 1,4-bis (2-chlorophenoxy) benzene, 1,4-bis (4-methylphenoxy) benzene, 1,4-bis (3-methylphenoxymethyl) Benzene, 1- (4-chlorobenzyloxy) -4-ethoxybenzene, 4,4'-diphenoxydiphenyl ether, 1,4-bis (4-benzylphenoxy) benzene, 1,4-bis (4-methylphenoxymethoxy) Methyl) benzene and the like. These can be used alone or in combination of two or more.

In particular, 4-benzylbiphenyl, m-terphenyl, 2-benzyloxynaphthalene, bis (4-methylbenzyl) oxalate, and 1,2-bis (3-methylphenoxy) ethane are preferably used.

As the support, paper, coated paper, synthetic paper,
A plastic film or the like is used.

Examples of the water-soluble binder include methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, starches, styrene-maleic anhydride copolymer hydrolyzate, ethylene-maleic anhydride copolymer hydrolyzate, and isobutylene-maleic anhydride copolymer. Polymer hydrolyzate, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyacrylamide and the like are used.

As the pigment, organic and inorganic pigments can be used. Preferred specific examples include calcium carbonate,
Examples include barium sulfate, titanium oxide, aluminum hydroxide, amorphous silica, urea formalin resin powder, polyethylene resin powder, and the like.

As the water-insoluble binder, styrene-
Butadiene rubber latex, acrylonitrile-butadiene rubber latex, vinyl acetate emulsion and the like are used as needed.

As a sticking preventive, stearic acid, carnauba wax, paraffin wax, carboxy-modified wax, polyethylene wax, zinc stearate, calcium stearate, aluminum stearate and the like are used.

Examples of the anti-adhesion agent include inorganic pigments such as kaolin, clay, talc, calcium carbonate, titanium oxide, and silica; and organic pigments such as styrene microballs, nylon powder, polyethylene powder, urea, formalin resin filler, and starch. Used.

Examples of the ultraviolet absorber include benzophenone and its derivatives, benzotriazole and its derivatives, benzoin and its derivatives, 2-chloroanthraquinone,
Benzyl peroxide, salicylates such as pt-butylphenyl salicylate, and cyanoacrylates such as ethyl diphenylacrylate can be used.

As antioxidants, 2,6-di-t-butyl-4-methylphenol, di (3-t-butyl-4)
-Hydroxy-5-methylphenyl) thioether,
1,1-bis (2-methyl-4-hydroxy-5-t-
Hindered phenols such as butylphenyl) butane; di (2,2,6,6-tetramethyl-4 sebacate)
Hindered amines such as (piperidine).

As the pigment, inorganic and inorganic pigments can be used. Preferred specific examples include calcium carbonate,
Examples include zinc oxide, titanium oxide, zinc hydroxide, aluminum hydroxide, amorphous silica, calcined clay, talc, urea formalin resin, polyethylene resin, polystyrene resin, and styrene / methacrylic acid polymer.

The heat-sensitive recording material of the present invention is produced, for example, according to the following method.

A color former, a developer and a sensitizer are dispersed together with an aqueous solution of a water-soluble polymer such as polyvinyl alcohol using an attritor, a sand mill or the like so that the particle diameter of the drug becomes several microns or less. The sensitizer may be dispersed simultaneously with one or both of the color former and the developer, or in some cases, a eutectic with the color former or the developer may be prepared and dispersed in advance. Is also good. These dispersions are mixed, and if necessary, pigments, binders, waxes, metal soaps, antioxidants, ultraviolet absorbers and the like are added to obtain a heat-sensitive coating liquid.

Mixing ratio (weight ratio) of color former and developer
Is from 0.5 to 3 times, preferably from 1 to 2.5 times, the color developer to the color former 1.

The obtained heat-sensitive coating liquid is applied to a support such as a high-quality paper, a synthetic paper, a plastic film or the like, dried and then smoothed by calendering to obtain a heat-sensitive recording material. In addition, the heat-sensitive coating liquid may be applied to a support having a heat insulating layer such as a plastic pigment or silica, as needed, in order to improve the color development. Further, in order to impart water resistance and chemical resistance, an overcoat layer such as a water-soluble polymer may be provided on the heat-sensitive recording layer as needed.

[0057]

The present invention will be described more specifically with reference to the following examples.

Example 1 Preparation of Coloring Agent Dispersion 3 g of β-type crystal modification of 2- (3-methylanilino) -3-methyl-6-diethylaminofluorane was placed in 70 g of a 2% aqueous solution of polyvinyl alcohol using a sand mill. Then, the resulting mixture was pulverized so that the average particle size became 1 μm to obtain a color former dispersion.

Preparation of Developer Dispersion Solution 4 g of 4,4'-bis (p-toluenesulfonylaminocarbonylamino) diphenylmethane and 3 g of sensitizer p-benzylbiphenyl were mixed in a 75% aqueous 2% polyvinyl alcohol solution by sand milling. To obtain a developer dispersion liquid.

Preparation of heat-sensitive coating solution After the above color former dispersion and developer dispersion were mixed in total, 15 g of calcium carbonate was dispersed in 50 ml of water and 15 g of a 30% paraffin wax dispersion were added. Then, the mixture was mixed well to obtain a heat-sensitive coating liquid.

Preparation of heat-sensitive recording material The obtained heat-sensitive coating liquid was coated on a high-quality paper at a solid content of about 5 g /
m and dried, and then calendered to adjust the Bekk smoothness of the surface of the heat-sensitive recording layer to about 300 seconds to obtain a heat-sensitive recording material.

(Comparative Example 1) In place of the β-form modification of 2- (3-methylanilino) -3-methyl-6-diethylaminofluoran which is the color former in Example 1,
A heat-sensitive recording material was prepared in the same manner as in Example 1, except that anilino-3-methyl-6- (N-ethyl-N-isopentylamino) fluoran was used.

(Comparative Example 2) Instead of 4,4'-bis (p-toluenesulfonylaminocarbonylamino) diphenylmethane which is a developer in Example 1, 2,2-
A heat-sensitive recording material was produced in the same manner as in Example 1, except that bis (p-hydroxyphenyl) propane was used.

(Evaluation) A reflection densitometer RD-914 was applied to each of the heat-sensitive recording materials obtained in Example 1 and Comparative Examples 1-2.
(Macbeth) was used to measure the background whiteness. next,
Using a printing device TH-PMD (manufactured by Okura Electric Co., Ltd.), the pulse width was adjusted so that the color image density (OD value) was about 1.1, and a color image was obtained. An oil resistance test and a plasticizer resistance test were performed on the color image, and the stability of the color image was evaluated by the residual ratio. Table 1 shows the results.

Residual rate (%) = (color image density after test / color image density before test) × 100 The lower the background whiteness, the higher the whiteness, and the higher the residual rate, the higher the whiteness. The higher the stability, the higher the stability of the color image.

Oil resistance test A salad oil was applied to the color image, excess salad oil was wiped off, and after standing at room temperature for 3 hours, a reflection densitometer RD-91 was used.
In step 4, the residual image density was measured.

Test for Plasticizer Resistance Dioctyl phthalate was applied to the color-developed image, excess was wiped off, left at room temperature for 3 hours, and the residual image density was measured with a reflection densitometer RD-914.

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[Table 1] Background whiteness and storage stability of color image ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Background whiteness before test Residual rate (%) ─────────── (OD value) Concentration (OD value) Oil resistance Plasticizer resistance {Example 1 0.07 1.11 97 71} {Comparative Example 1 0.08 1.10 91 65 Comparative Example 2 0.07 1.12 21 13} ━━━━━━━━━━

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According to the present invention, as is apparent from Table 1,
In particular, a heat-sensitive recording material excellent in oil resistance and plasticizer resistance of a color image could be provided.

Claims (3)

[Claims] 1. A thermosensitive recording material utilizing a color reaction between a colorless or light-colored electron-donating color former and an electron-accepting color developer capable of forming a color upon contact with said color-developing agent. The following general formula (1) [Wherein, R ₁ and R ₂ each independently represent a carbon atom of 1
5 to 5 alkyl groups. And at least one fluoran compound represented by the following general formula (2): Wherein R ₃ is Is shown. ] A thermosensitive recording material comprising at least one ureide compound represented by the formula: 2. The fluoran compound of the general formula (1)
-(3-methylanilino) -3-methyl-6-diethylaminofluoran or 2- (3-methylanilino)-
2. The heat-sensitive recording material according to claim 1, which is 3-methyl-6-di-n-butylaminofluoran. 3. 2- (3-methylanilino) -3-methyl-6-diethylaminofluoran has a diffraction angle (2θ) of 7.6 ° in a powder X-ray diffraction method using Cu-Kα ray,
12.2 °, 14.9 °, 15.9 °, 17.6 °, 2
3. The heat-sensitive recording material according to claim 2, which is a β-form crystal modification characterized by an X-ray diffraction pattern showing a characteristic peak at 2.8 °.