JPH0486286A - Thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a thermal recording material which donates adequate performance to various functions such as coloring properties as well as high sensitivity and solvent resistance by allowing the presence of fluoran derivative having an alkylamino group substituted by an aryloxy group or an arylthio group at the 6th position as an electron-donative colorless dye. CONSTITUTION:A thermal recording material containing an electron-donative colorless dye and an electron-receptive compound consists of a thermally coloring layer containing a fluoran derivative with an alkylamino group substituted by an aryloxy group or an arylthio group at the 6th position as an electron- donative colorless dye, provided on a support having a smoothness degree of 500sec. or higher as specified by JIS-P-8119. The fluoran derivative is such as 2-anilino-3-methyl-6-N-ethyl-N-(2-phenoxyethyl)amino fluoran, for example.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material in which a coloring layer containing an electron-donating colorless dye and an electron-accepting compound is provided on a support. Concerning recording materials.

(Prior Art) Recording materials using electron-donating colorless dyes and electron-accepting compounds are already well known as pressure-sensitive paper, thermal paper, light-sensitive pressure-sensitive paper, electrically conductive thermal recording paper, thermal transfer paper, and the like. For example, British Patent No. 2,140,449, US Patent No. 4.48
No. 0.052, No. 4.436,920, Special Publication No. 1983
-23992, JP-A-57-179836, JP-A No. 60
-123556, 60-123557, etc. for details. In particular, heat-sensitive recording materials are detailed in Japanese Patent Publications No. 43-4160 and Japanese Patent Publication No. 45-14039.

These thermal recording systems are being applied to a wide range of fields such as facsimiles, printers, and labels, and their needs are expanding. In the past, there was a strong demand for high-speed recording, low-energy printing, head matching properties, etc., but recently, with the expansion of applications, there has been a growing demand for heat-sensitive recording materials that are highly sensitive and have excellent background preservation. There is. In particular, it is the resistance when using products that use solvents, such as solvent pens, diazo copying materials, and adhesives that are often used as office supplies, and also the resistance in the storage state of printing. In order to meet these requirements, many proposals have been made, including the use of protective layers and the use of solvent-resistant color developers. However, these methods have not been able to achieve high sensitivity. In addition, the present inventors have found that solvent resistance can be imparted by using a fluoran derivative having an alkylamino group substituted with an aryloxy group or an arylthio group at the 6-position. The problem was that the sensitivity was lower than the high-sensitivity color formers currently available.

(Objective of the Invention) An object of the present invention is to provide a heat-sensitive recording material that has sufficient performance in various properties including color development characteristics, and has high sensitivity and solvent resistance.

(Structure of the Invention) An object of the present invention is to provide a heat-sensitive recording material containing an electron-donating colorless dye and an electron-accepting compound, in which the electron-donating colorless dye is substituted with an aryloxy group or a 7-arylthio group at the 6-position. J I 5-P-8+
The heat-sensitive recording material is characterized by being provided on a support with a smoothness defined by +9 for 500 seconds or more.

The electron-donating colorless dye used in the present invention is an allyl 7 substituted with an aryloxy group or a 7-aryldio group at the 6-position.
Among the fluoran derivatives having a mino group, those represented by the following general formula [1] are particularly preferred.

(In the formula, R1 and R3 are an alkyl group, an alkenyl group,
Alkynyl group, aryl group, hydrogen atom, R2 is hydrogen atom, alkyl group, alkoxy group, halogen atom, R4
is a hydrogen atom alkyl group, alkenyl group, alkynyl group,
Aryl group, aldoxy group, aryloxy group, alkylthio group, halogen atom, substituted amine group, Schiff) group, nitro group, acyl group, trihalomethyl group, sulfamoyl group, × represents oxygen atom or sulfur atom, Ar and ring A
represents an aromatic ring which may contain a heteroatom, and n is 1 to 1.
An integer of 0 and m represent an integer of 1 to 3.

The xanthine ring or ring A may have a plurality of the same or different substituents, and in this case, the substituents represent an alkoxy group, a halogen atom, or a nitro group.

The group represented by R1 in the above general formula [1] further includes an alkyl group, an alkenyl group, an alkynyl group, an aryl group,
It may be substituted with an alkoxy group, an aryloxy group, an alkylthio group, a halogen atom, a substituted 7-mino group, a cyano group, a nitro group, an acyl group, a trihalomethyl group, a sulfamoyl group, a heterocyclic residue, or the like. These substituents may further have a substituent. As R1, H, CR3I CII R2, -I Y ZlCn
H2n -3, C0R2, OC-R2--I Y
Z - (n is an integer of 2 to 10, m is an integer of 1 to 5, Y and 2 are hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, aryl groups, alkoxy groups, aryloxy groups, alkylthio groups, halogen atoms , a substituted amine group, a cyano group, a nitro group, an acyl group, a trihalomethyl group, a sulfamoyl group, and a hetero residue) are preferred.

Especially preferred as R is a methyl group, ethyl group, propyl group, butyl group, etc.

In the above formula, the group represented by R2 is preferably an alkyl group, an alkenyl group, an alkynyl group, an acetoxy group, or a halogen atom, and particularly preferably a methyl group, an ethyl group, a methoxy group, a methoxymethyl group, a methylthio group, or a chlorine atom.

In the above formula, the group represented by R3 is a hydrogen atom, and has 1 to 1 carbon atoms.
8 is preferable, and a hydrogen atom and an ethyl group are particularly preferable.

R4 is preferably a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, or an alkenyl group, and may further have a substituent such as a halogen atom or an alkoxy group.

1 to 3 R4s can be substituted on the benzene ring, and in the case of multiple R4s, they may be the same or different.

When R3 is a hydrogen atom, R4 is preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. When R3 is an ethyl group, %R4 is preferably a trifluoromethyl group, a nitro group, a cyan group, a sulfamoyl group, or the like.

In the above formula, the ring is preferably a Hensen ring, a naphthalene ring, a pyridine ring, a pyrimidazine ring, an indole ring, and particularly a Hensen ring.

When the ring is substituted with the same or different substituents, the substituent is preferably a halogen atom, a nitro group, a cyano group, an alkoxy group, etc., and a chlorine atom or a fluorine atom is particularly preferable.

The aromatic ring represented by Ar in the above formula is preferably a benzene ring, a naphthalene ring, a pyridine ring, a furan ring, a coumarin ring, etc., and a Hensen ring or a naphthalene ring is particularly preferred.

As a substituent for Ar, a saturated or unsaturated furkyl group,
Cycloalkyl group, aryl group, hydroxy group, alkoxy group, alkylthio group, aryloxy group, arylthio group, halogen atom, dialkylamino group, carbonyl group, carboxyl group, carboxyl group, carbamoyl group, alkoxycarbonyl group, acyl group, cyano A group, a nitro group, a sulfonyl group, an isocyanate group, and a heterocyclic residue are preferred. These substituents may further have similar substituents; for example, for alkyl groups,
Examples include alkoxyalkyl groups, haloalkyl groups, aralkyl groups, and hydroxyphenyl-substituted alkyl groups. Furthermore, the molecule may contain several phenolic compounds via substituents.

In particular, substituents for Ar include methyl group, ethyl group, isopropyl group, t-butyl group, pencil group, methoxymethyl group, phenoxymethyl group, cyclohexyl group, methoxy group, ethoxy group, phenoxymethoxy group, phenoxyethoxy group, Phenoxypropoxy group, chloroethoxy group, methylthio group, ethylthio group, phenylthioethoxy group, phenoxy group, nilthio group, phenoxyethylthio group, 7-cedyl group, acetoxy group, methoxycarbonyl group, cyano group, formyl group, trifluoromethyl group, diethylamino group, chlorine atom, fluorine atom, etc. are preferable.

In the above general formula (1), n is preferably an integer of 2 to 6, and the divalent group represented by -(CH2) or - may be linear or branched.

Specific examples of the fluoran derivatives according to the present invention are as follows:
-7nilino3-methyl-6-N-edjiruN-(2-
phenoxyethyl)aminofluorane, 2-7nilino3-methyl-6-N-edyl-N-(3-phenoxyprobyl)aminofluorane, 2-7nilino3-methyl-6-N-conityl-N-( 3-(4-methoxyphenoxy)propyl)aminofluorane, 2-7nilino 3
-Methyl-6-N-edyl-N-(3-(4-methylthiophenoxy)propylcoaminofluorane).

2-7 Nilino 3-methyl-6-N-ethyl-N-(3
-(4-methoxyphenylthio)propyl)aminofluorane, 2-7nilino-3-methyl-6-N-ethyl-
N-(3-(3-methylphenoxy)propylcoaminofluorane, 2-7nilino3-methyl-6-N-ethyl-N-[3-(3,5-difluorophenoxy)propylcoaminofluorane, 2 -7 Nilino 3-methyl-
6-N-edyl-N-(3-(2-naphdyloxy)propylcoaminofluorane, 2-anilino II-3-methyl-6-N-ethyl-N-[3-・[4-(
2-phenoxyethoxy)phenoxy]propyl]aminofluorane, 2-p-ethylanilino-3-methyl-
6-N-ethyl-N-(2-(4-methoxynaphthyloxy)ethyl)aminofluorane, 2-N-methyl-N
-(3-trifluoromethylphenyl)-6-N-ethyl-N-(3-phenoxyprobyl)aminofluorane 2-N-ethyl-N-(2,4-dimethylamino)-6
-N-Ethyl-N-(3-(4-methylthiophenoxy)propylcoaminofluorane 2-phunilino 3-methyl-6-N-ethyl-N-)2- (4-(4-methoxyphenoxy)phenoxy) Ethylcoaminofluorane, 2-7nilino-3-methyl-6-N-ethyl-N-[
2(2-methylphenoxy)ethylcoaminofluorane 2-anilino-3-methyl-6-N-ethyl-N-(
2-(3-methylphenoxy)ethyl lahminofluorane, 2-7nilino-3-methyl-6-N-ethyl-N-
(2-(4-methylphenoxy)ethylcoaminofluorane, 2-7nilino-3-medyl-6-N-ethyl-
N-[2(2-ethylphenoxy)ethyl]a≧nofluorane, 2-7nilino3-methyl-6-N-ethyl-
N-(2-(3-ethylphenoxy)ethylcoaminofluorane, 2-7nilino3-methyl-6-N-ethyl-N-(2-(4-ethylphenoxy)ethylcoaminofluorane, 2- Allino 3-methyl-6-N-ethyl-N-(2-(2-methoxyphenoxy)ethylcoaminofluorane, 2-7nilino 3-methyl-6-N-ethyl-N-(2-(3-methoxy) phenoxy)ethylcoaminofluorane, 2-7nilino-3-methyl-6-N
-ethyl-N-(2-(4-methoxyphenoxy)ethyl)7minofluorane, 2-anilino-3-methyl-6
-N-ethyl-N-(2-(3,5-difluorophenoxy)ethyl)aminofluorane, 2-7nilino3-
Methyl-6-N-ethyl-N-(2-(4-fluorophenoxy)ethylcoaminofluorane, 2-7 dilino-3-methyl-6-N-ethyl-N-[2-(4-chlorophenoxy) )ythylcoaminofluorane, 2-7nilino3-methyl-6-N-edyl-N-(2-(4-methylthiophenoxy)ethyl)7minofluorane, 2-7
Nilino 3-methyl-6-N-ediru N-(2-(4
-ethylthiophenoxy)ethyl)aminofluorane.

2-7 Nilino 3-methyl-6-N=ethyl-N-(4
-(4-ethyl fluoride)butylcoaminofluorane,
2-7 Nilino 3-methyl-6-N=ethyl-N-(1
-methyl-2-phenoxyethyl)aminofluorane,
2-anilino-3-methyl-6-N-ethyl-N-(4
-(4-methoxyphenoxy)butyl)aminofluorane, 2-anilitwo-3-methyl-6-N-ethyl-N(
4-(3-methylphenoxy)butyl)aminofluorane, 2-7nilino-3-methyl-6-N-ethyl-N-C
2-(2-methylphenoxy)ethyl)aminofluorane, 2-7nilino-3-methyl-6-N-ethyl-N-
(2-(2-methylphenoxy)ethylcoaminofluorane, 2-p-ethylanilino-3-methyl-6-N-
Ethyl-N-(2-(4-ethylphenoxy)ethylcoaminofluorane, 2-N-methyl-N(3-trifluoromethylphenyl)amino-6N-ethyl-N-(2
-(2-ethylphenoxy)ethylcoaminofluorane, 2-ethyl(2,4-dimethylphenyl)amino-6
-N(2-(4-methoxyphenoxy)ethyl)aminofluorane, 2-7nilino3-methyl-6-N-tetrahydrofurfuryl-N-(2-(4ethylphenoxy)ethylcoaminofluorane).

2-anilino-3-methyl-6-N-1-lyruN(2
-(4-ethylphenoxy)ethylcoaminofluorane, 2-anilino-3-methyl-6N-cyclohexyl-
N-(2-(4-ethylphenoxy)ethylcoaminofluorane, 2-anilino-3-methoxy-6-N-ethyl-N-C2-(4-ethylphenoxy)ethyl)aminofluorane, 2-7 Nilino-3-chloro-6-N-N-(2-(4-ethylphenoxy)ethyl)aminefluoran 12-anilino-3-nhexyl-6-
N-ethyl-N-(2-(4-ethylphenoxy)ethyl)7minofluorane 12-(2,4-dimethyl)anilino-3-meth-6-N-ethyl-N-(3-(4
-ethylphenoxy)ethylcoaminofluorane, 2-
o-Fluoroanilino-3-methyl-6-N-ethyl N
-(3-(4-ethylphenoxy)propylcoaminofluorane, 2-o-chloroanilino-3-methyl-6-
N-ethyl-N-(3-(4-ethylphenoxy)propyl)aminofluorane 2-7 nilino 3-methyl-6
-N-ethyl-N-(2-phenoxypropyl)7minofluorane.

2-anilino-3-methyl-6-N-ethyl-N-(3
-(4-ethylphenoxy)propylcoaminofluorane, 2-7nilino-3-methyl-6N-ethyl-N-(
3-(4-n-propylphenoxy)propyltafminofluorane, 2-7nilino 3-methyl-6-N-ethyl-N-[3-(4-iso-propylphenoxy)propyl)aminofluorane, 2 -7 Nilino 3-methyl-6-N-ethyl-N-(3-(4-n-butylphenoxy)propyl)aminofluorane, 2-7 Nilino 3
-Methyl-6-N-ethyl-N-(3(4-iso-butylphenoxy)propyl)aminofluorane, 2-7nilino3-methyl-6-N-ethyl-N-(3-(4
-tertbutylphenoxy)propyl)aminofluorane, 2-anilino-3-methyl-6-N-ethyl-N
-(3-(4-allylphenoxy)propylcoaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N-(3-(3-ethylphenoxy)propylcoaminofluorane, 2-7 Nilino 3-methyl-6-N-ethyl-N-(3-(2-phenylphenoxy)propylcoaminofluorane, 2-anilino-3-methyl-6-
N-ethyl-N-(3-(3,5-dimethylphenoxy)propyl)aminofluorane, 2-anilino-3-methyl-6-N-ethyl-N-(3-(2-fluorophenoxy)propylco) Aminofluorane, 2-7nilino-3-methyl-6-N-edyl-N-(3-(2-cyclohexylphenoxy)propyl)aminofluorane, 2
-anilino-3-methyl-6-N-ethyl-N-(3-
(3-fluorophenoxy)propylcoaminofluorane, 2-7nilino3-methyl-6-Nethyl-N-(
3-(3,5-dichlorophenoxy)propyl)aminofluorane, 2-7nilino 3-methyl-6-N-ethyl-N-(3-(2ethylphenoxy)propyl)aminofluorane, 2-7nilino Examples include 3-methyl-6-N-ethyl-N-(3-(3,5-difluorophenoxy)propylcoaminofluorane).

The electrochromic colorless dyes according to the present invention include conventionally known triphenylmethane compounds, fluoran compounds, phenothiazine compounds, indolylphthalide compounds, leucoauramine compounds, rhodamine lactam compounds, It can be used in combination with various compounds such as phenylmethane compounds, triazene compounds, spiropyran compounds, and fluorene compounds.

Specific examples of phthalides are given in U.S. Patent Reissue Patent Specification No. 23.
No. 024, U.S. Patent No. 3,491,111, U.S. Patent No. 3
No. 491112, No. 3491116 and No. 350
No. 9174, specific examples of fluorans are U.S. Patent No. 3,624,107, U.S. Pat.
No. 1011, No. 3462828, No. 368139
No. 0, No. 3920510, No. 3959571,
Specific examples of spiropyrans are shown in U.S. Patent Specification No. 397180.
No. 8, pyridine-based and pyrazine-based compounds are described in U.S. Pat. No. 3,775,424, U.S. Pat. .

The electron-accepting compound used in the present invention includes phenol derivatives, metal salts of aromatic carboxylic acids, acid clay, bentonite, novolac resins, metal-treated novolac resins, metal complexes, and the like. These examples are
No. 09, JP 45-14039, JP 52-14
No. 0483, JP-A-48-51510, JP-A-57-
2 + 0886, JP 58-87089, JP 59-11286, JP 60-176795,
It is described in Japanese Patent Application Laid-Open No. 61-95988.

To give some examples of these, phenolic compounds include 2,2°-bis(4-hydroxyfer)propane, 4-phenylphenol, 1,1-bis(3-'7
0rho4-hydroxyphenyl)cyclohexane, 1
, 1-his(4-hydroxyphenyl)cyclohexane, 1,1-bis(3-chloro-4-hydroxyphenyl)-2-ethylbutane, 4,4'-5ec-inocdylidenzyphenol, 4,4'' -5ec-butylidene diphenol, 4-p-megluphenylphenyl Tnol, 4.4゛-methylcyclo\1cylideneph]nol,
4゜4'-isobenzylidenephenol, his(3-aryl-4-hydroxyphenyl)sulfone, 4hydroxyphenyl-3゛4' dimethylfersulfone,
Examples include 4-(4-impropoxyphenylsulfonyl)phenol, his(2-(4-hydroxyphenylthio)ethoxy)methane, and Hensyl p-hydroxybenzoate. Salicylic acid derivatives include 4-pentadecyl salicylic acid, 3,5-di(α-methylhensyl) salicylic acid,
3,5-di(ter-octyl)salicylic acid, 5-α-
(p-α-methylhensylphenyl)ethylsalicylic acid, 3-α-methylhensyl-5-ter-octylsalicylic acid, 5-tetradecylsalicylic acid, 4-hexyloxysalicylic acid, 4-cyclohexyloxysalicylic acid, 4-decyloxysalicylic acid , 4-dodecyloxysalicylic acid, 4-pentadecyloxysalicylic acid, 4-octadecyloxysalicylic acid, etc., and salts thereof such as zinc, aluminum, calcium, copper, etc. Among these, hisphenols are preferred.

It is preferred to use thermofusible substances in the present invention, specific examples include 4-chlorohensyl 4'-methoxyphenyl ether, 4-methoxyhensyl-4'-chlorofuconyl ether, 4-chlorohensyl-4 '-Ethoxyphenyl ether, 4-ethoxypencyl-4'-chlorophenyl ether, 4-propoxybenzyl-4'-
Chlorophenyl ether, 4-chlorobenzyl-2'-
Propoxyphenyl ether, 4-butoxybenzyl-
4'-chlorophenyl ether, β-naphthylhenzyl ether, II 2-bis-(4-methoxyphenoxy)propane, II 2+-his-(4-ethoxyphenoxy)propane, 1-(4-methoxyphenoxy)-2
-(4-ethoxyphenoxy)propane, '1-(4-
1-toxyphenoxy)-2-(4-methoxyphenoxy)propane, 112-his-(2-methoxyphenoxy)propane, 1-(4-methoxyphenoxy)-2-
(2-methoxyphenoxy)propane, 1-(4-methoxyphenoxy)-2-phenoxypropane, 1-(4
-methoxyphenoxy)-2-(4-methoxyphenoxy)propane, ]-(]4-methoxyphenoxy-2-
Aromatic ether compounds such as (4-chlorophenoxy)propane, 1-(4-methoxyphenoxy)-2-(4-fluorophenoxy)propane, II 2-bis-(3-methoxyphenoxy)phenoxypropane, Medi Lornutearylamide, stearic acid amide, palmitic acid amide, te[・lacuccinic acid amide, N-phenyl stearic acid amide, N-phenyl palmitic acid amide, N
-Amides such as stearyl urea, N-palmitine oxygen, and p-benzylbiphenyl, and aromatic hydrocarbons.

It is preferable to add wax to the present invention, with a melting point of 4
Examples of waxes with a temperature of 0 to 120°C include paraffin wax, polyethylene wax, carnauba wax, microcrystalline wax, campria wax, and montan wax.

The smoothness of the support according to the present invention must be at least 500 seconds, and preferably at least 800 seconds. To obtain the support of the present invention, (1) Use a material with high flatness such as synthetic paper or plastic film.

■ An undercoat layer containing pigment as the main component is provided on the support.

■ There are ways to increase the smoothness of the support by using a super calender or the like.

As the above-mentioned pigment, any general organic or inorganic pigment can be used, and it is particularly preferable to use one having an oil absorption of 40 cc/1009 or more as defined in JIS-5101. Specific examples include calcium carbonate, barium sulfate, titanium oxide, talc, waxite, kaolin, calcined kaolin, aluminum hydroxide, amorphous silica, urea-formalin resin powder, polyethylene resin powder, and the like.

When these pigments are applied onto a support, the amount of pigment is 297 m2 or more, preferably 49/m2 or more.

Binders used in the undercoat layer include water-soluble polymers and water-insoluble polymers, and the binders may be used alone or in combination of two or more.

Examples of water-soluble polymers include methylcellulose, ruboxymethylcellulose, hydroxyethylcellulose, starches, gelatin, gum arabic, casein, styrene-hydrohydric maleic acid copolymer hydrolyzate, ethyl [non-maleic anhydride copolymer hydrolyzate] , isophylene-maleic anhydride hydrolyzate, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyacrylamide, and the like.

As the water-insoluble binder, synthetic rubber latex or synthetic elbow fat emulsion is generally used, and examples include styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, meddy-butadiene acrylate rubber latex, and vinyl acetate emulsion. It will be done.

Next, a typical method for producing a heat-sensitive color forming layer of the present invention will be described.

The electron-donating colorless dye, the electron-accepting compound, and the sensitizer are dispersed to a size of several microns or less together with an aqueous solution of a water-soluble polymer such as polyvinyl alcohol using a ball mill, sand mill, or the like. The sensitizer is added to either the electron-donating colorless dye or the electron-accepting compound, or both, and is dispersed simultaneously, or in some cases, a eutectic product is prepared in advance with the electron-donating colorless dye or the electron-accepting compound. , may be dispersed.

These dispersions are mixed and, if necessary, pigments, surfactants, binders, metal soaps, waxes, antioxidants, ultraviolet absorbers, etc. are added to form a heat-sensitive coating liquid. The obtained heat-sensitive coating liquid can be applied to high-quality paper, high-quality paper with an undercoat layer, synthetic paper, plastic film, etc., and has a smoothness of 500 seconds or more as defined in JIS--5+01 described in the present invention. After being coated and dried on a support, smoothness is imparted by calendering to obtain the desired heat-sensitive recording material.

As the metal soap, higher fatty acid metal salts are used, such as zinc stearate, calcium stearate, aluminum stearate, and the like.

Furthermore, surfactants, antistatic agents, ultraviolet absorbers, antifoaming agents, conductive agents, fluorescent dyes, coloring dyes, and the like may be added as necessary.

The applied heat-sensitive recording material is dried and subjected to a process such as a calender before being used.

Further, a protective layer may be provided on the thermosensitive coloring layer if necessary. The protective layer may be any one known as a protective layer for heat-sensitive recording materials.

Furthermore, if necessary, a back coat layer may be provided on the opposite side of the support of the heat-sensitive recording material from the heat-sensitive coloring layer. As the backcoat layer, any known backcoat for heat-sensitive recording materials can be used.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited only to the Examples below.

(Preparation of Undercoat Paper A) Calcined kaolin (Ansilex 9Q: manufactured by Engelhard) 809 was dispersed with a 0.5% aqueous solution of sodium hexametaphosphate 1609 using a homogenizer.

Add 48% styrene-buxien latex (manufactured by Sumitomo Naugatuck) to this dispersion J 60 q + 0! ! The coating solution obtained by adding the above was applied onto a high-quality paper of 50 q/m2 using a wire bar to a dry coating weight of 69/m2, and dried in an oven at 50°C to obtain an undercoated paper.

This undercoated paper was subjected to supercalender treatment at a linear pressure of 50 kc+/cm to obtain undercoated paper A. This smoothness is 85
It was 0 seconds. (Smoothness of high quality paper is 150 seconds) (Preparation of undercoat paper B) Super calender treatment of undercoat paper A at linear pressure 100k
Undercoat paper B was obtained in the same manner as undercoat paper A except that q/am was changed. The smoothness was 1150 seconds.

(Preparation of Undercoat Paper C) Undercoat Paper C was obtained by supercalendering the Undercoat Paper A. The smoothness was 300 seconds.

(Example-1) 2-7nilino-3methyl- as an electron-donating colorless dye
6-N-ethyl-N-(3-(4-ethylphenoxy)
Bisphenol A as a propylcoaminofluorane electron-accepting compound and β-naphthylbenzyl needle as a thermofusible compound, each 209, were dispersed in a ball mill overnight with a 5% aqueous solution of polyvinyl alcohol (Clara PVA-105) of 1009, and the average Each dispersion was obtained with a particle size of 1.5 μm or less. In addition, calcium carbonate 80
9 was homogenized and dispersed with 0.5% sodium hexametaphosphate solution 1609 to obtain a pigment dispersion.

The dispersions prepared as described above were mixed in a ratio of 59 parts of an electron-donating colorless dye dispersion, 109 parts of an electron-accepting compound dispersion, 1.9 parts of a β-naphthylbenzyl ether dispersion, and 59 parts of a calcium carbonate dispersion. Furthermore, 21% zinc stearate emulsion 39 paraffin wax dispersion (manufactured by Middle East Yushi Co., Ltd., Hyde LJ-D-33'7i average melting point 68°
c) 59 was added, 25% shisobutylene-maleic anhydride oligomer sodium salt aqueous solution (molecular weight 2000-3
000, Demol FP (manufactured by Hanadama Co., Ltd.) 0.79 was added to obtain a heat-sensitive coating liquid. Apply this heat-sensitive coloring layer coating solution onto the undercoat paper A using a wire bar to calculate the dry weight of the coating layer.
The film was coated so as to have a temperature of 100° C. and dried for 1 minute at 50° C. to obtain thermosensitive recording paper.

(Example 2) A thermosensitive recording material was obtained in the same manner as in Example 1, except that the thermosensitive coloring liquid of Example 1 was applied to subbing paper B.

(Example-3) Example-3 except that 2-7nilino-3-methyl-6-N-ethyl-N-(3-(2-ethylphenoxy)propylcoaminofluoran) was used as the electron-donating colorless dye.
A thermosensitive recording material was obtained in the same manner as in Example 1.

(Comparative Example-1) High-quality paper (smoothness 15
A heat-sensitive recording material-4 was obtained in the same manner as in Example-1 except that 0 seconds) was used.

(Comparative Example-2) A heat-sensitive recording material was obtained in the same manner as in Example-1 except that undercoat paper C was used instead of undercoat paper A in Example-1.

(Comparative Example-3) Instead of 2-7nilino-3-methyl-6-N-ethyl-N-(3-(4-ethylphenoxy)propylcoaminofluorane in Example-1), 2-alino-3- Methyl-
Example except that 6-diethylaminoflurane was used
A thermosensitive recording material was obtained in the same manner as in Example 1.

The thermal recording paper was evaluated as follows.

■Color density was determined using a Kyocera printing tester with a printing energy of 30m.
Printing was performed at J/mm2, and the color density was measured using a Macbeth densitometer. The higher this value, the higher the sensitivity of the thermal recording paper.

■For heat resistance evaluation, the density of the white background area and the density of the printed area with a color density of 1.3 (printed with a Kyocera printing tester) were measured using a Maches densitometer after being left at 60°C and 30% RH for 24 hours. . The density of the white background part is low and the density of the printed part is high, or it has a high shelf life.

■For chemical resistance evaluation, use ethanol Q and LCC with a dropper.
(Thermal recording t,=+ It was dropped onto the soil, and fogging was visually observed and evaluated as follows.

○ No fogging has occurred. × Fog has occurred. :3 Table 1

Claims (1)

[Claims] In a heat-sensitive recording material containing an electron-donating colorless dye and an electron-accepting compound, 6 as the electron-donating colorless dye.
A heat-sensitive coloring layer containing a fluorane derivative having an alkylamino group substituted with an aryloxy group or an arylthio group at the position thereof is provided on a support having a smoothness of 500 seconds or more as defined in JIS-P-8119. Features of heat-sensitive recording material.