JPH08156406A - Thermal recording material - Google Patents

Abstract

PURPOSE: To provide a thermal recording material fitted to the original mechanism of a serial printer, not generating head up.down contamination and strip like contamination at all and not also generating the shift of a vertical rule. CONSTITUTION: In a thermal recording material wherein a thermal color forming layer containing an electron donating leuco dye and an electron acceptive coupler is provided on a support, paraffin wax of which the melting start temp. of a heat absorption peak obtained by differential thermal analysis is 60 deg.C or higher and metal stearate with an average particle size of 2-10μm are added to the thermal color forming layer.

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 a recording method for the heat-sensitive recording material.

[0002]

2. Description of the Related Art A heat-sensitive recording material is usually a colorless electron-donating leuco dye (hereinafter referred to as a leuco dye) on a support such as paper, synthetic paper, or resin film, and an electron-accepting acidic acid that develops a color when heated. A thermosensitive coloring layer containing a substance (hereinafter referred to as a developer) as a main component is provided.
No. 4160, Japanese Patent Publication No. 45-14039 and the like. In recent years, such a thermal recording medium is recorded by a thermal head, but it has advantages of being able to obtain recording in a shorter time than other recording mediums, less noise generation, and low cost. Therefore, it is widely used for measuring recorders, computers, facsimiles, ticket vending machines, etc.

Recording methods using a thermal head include a horizontal single-row printing method using a horizontal single-row head for facsimiles and printers, a so-called line printing method, and a vertical single-row printing method using a vertical single-row head for a small printer, or There is a so-called serial printing method of a digit sequential printing method using a one-character head. Recently, in the field of Japanese word processors (hereinafter referred to as word processors), word processors that perform thermal recording by serial printing have rapidly spread due to their small size and low cost, and have become widely used at home. There is.

The serial printing type heat-sensitive recording adopted in this word processor is designed on the premise that it is also used as the heat-sensitive recording by the thermal transfer ribbon, and therefore has its own printing mechanism. That is, after the thermal recording medium is loaded into the printer, the thermal head is pressed against the thermal recording medium at the start of printing, and in that state the thermal head moves laterally to perform printing for one line, and at the end of printing, the thermal head moves to the recording medium. Get away from. While the thermal head is returning to the original recording start position, or at the same time when the thermal head returns to the original recording position, paper feeding is performed, printing of the next line is performed, and the same operation is sequentially repeated to perform recording for one page.

By the way, as a thermal recording material for a word processor which performs printing by a serial printing method, a thermal recording material for a line printing method such as a facsimile has been often used. However, since it is not adapted to the printing mechanism unique to the word processor of the serial printing method, a small amount of printing dust adhered to the thermal head is transferred to the recording start portion or the recording end portion of the print line, and unnecessary stains are caused. However, there is a problem in that (hereinafter, referred to as head-up / down dirt) or band-shaped dirt (hereinafter referred to as band-shaped dirt) is generated due to the pressing pressure (printing pressure) of the thermal head.

In the above serial printer, when a vertical ruled line different from the moving direction (horizontal direction) of the thermal head is printed, one line of vertical ruled line is printed, and after the printing is completed, the thermal head starts the original recording. Paper is fed while returning to the position or at the same time as returning, and vertical ruled lines are printed on the next line, and the same operation is sequentially repeated to print vertical ruled lines extending over a plurality of lines.

However, the vertical ruled line thus obtained is N
Since the vertical ruled lines of the line (n + 1) and the next (N + 1) line are slightly shifted (hereinafter, vertical ruled line shift), the appearance was inferior to that printed by a laser printer or the like. Regarding such head-up / down stains and band-like stains, see Japanese Patent Application Laid-Open Nos. 4-10976 and 4-70378.
Improvements are being considered, but not always of satisfactory quality. In addition, the improvement of the vertical ruled line shift has not been studied so far.

[0008]

SUMMARY OF THE INVENTION In consideration of the above-mentioned situation, the present invention is adapted to a mechanism unique to a printer of a serial printing system, does not cause head-up / down dirt, band-like dirt at all, and causes vertical ruled line shift. An object of the present invention is to provide a heat-sensitive recording material which does not exist and a recording method of the heat-sensitive recording material.

[0009]

That is, according to the present invention, a heat-sensitive recording material comprising a support and a heat-sensitive color-forming layer containing an electron-donating colorless dye and an electron-accepting developer is provided on the support. A heat-sensitive recording material comprising a paraffin wax having an endothermic peak having a melting start temperature of 60 ° C. or more obtained by a differential thermal analysis and a metal stearate having an average particle diameter of 2 to 10 μm in the color forming layer. Provided.

The first feature of the present invention is that the endothermic peak melting start temperature obtained by differential thermal analysis is 6 in the thermosensitive coloring layer.
The point is that paraffin wax having a temperature of 0 ° C. or higher is used.
Since such paraffin wax has an action of preventing adhesion of a heat-melting material such as a dye or a color developer to the thermal head during printing, head-up / down stains, band-like stains, etc. can be prevented. Such paraffin wax is commercially available as Hydrin E manufactured by Chukyo Yushi Co., Ltd.
-139, Hydrin F-516, etc. are on the market.
With a wax whose melting start temperature of the endothermic peak obtained by the differential thermal analysis is less than 60 ° C., the solidification of the hot melt after printing is delayed, the hot melt hinders the movement of the thermal head, and the vertical ruled line shift increases. However, the intended purpose of the present invention cannot be achieved.

The second feature of the present invention is that the thermosensitive color developing layer contains a metal stearate having an average particle diameter of 2 to 10 μm. That is, conventionally, a paraffin emulsion having a particle size of 2 μm or less is usually used for the purpose of improving head-up / down stains and band-like stains, and other materials constituting the thermosensitive coloring layer have an average particle size of 2 μm.
It is adjusted and used so that it is less than or equal to m. As a result of intensive studies made by the present inventors on this point, such a heat-sensitive recording material has high adhesion between the heat-sensitive color forming layer and the thermal head. It was found that misalignment and vertical ruled line misalignment occurred. As a result of further research, when a metal salt of stearic acid having an average particle diameter of 2 to 10 μm was contained in the thermosensitive coloring layer, the frictional resistance between the thermosensitive coloring layer and the thermal head was unexpectedly reduced, and vertical ruled line shift occurred. It was found that the occurrence of can be prevented at the same time.

When a metal stearate having an average particle size of less than 2 μm is used, the effect of reducing the frictional resistance between the heat-sensitive color forming layer and the thermal head is not sufficient, whereas when a metal stearate having a diameter of more than 10 μm is used. When the head is running, the metal stearate adheres as head dregs to produce band-like stains (gloss of head running marks), so the intended object of the present invention cannot be achieved. Examples of the metal stearate used in the present invention include zinc stearate, calcium stearate, aluminum stearate, lead stearate, magnesium stearate and the like, but zinc stearate is preferably used from the viewpoint of exhibiting the effect. .

In the present invention, the paraffin wax and the metal stearate are each contained in an amount of 10 to 300% by weight based on the electron-donating colorless dye contained in the thermosensitive color developing layer.
Preferably 30 to 250% by weight is used. 10% by weight
If it is less than the above range, the performance of the present invention cannot be sufficiently exhibited, which is not preferable. Further, if it exceeds 300% by weight, no further effect can be obtained, which is not preferable.

In the present invention, the leuco dyes used in the thermosensitive coloring layer may be used alone or in combination of two or more.
As such leuco dyes, those applied to this type of heat-sensitive material are arbitrarily applied, for example, triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, spiropyran-based, indolinophtalide-based, etc. Leuco compounds of dyes are preferably used. Specific examples of such leuco dyes include, for example, those shown below.

3,3-bis (p-dimethylaminophenyl)-
Phthalide, 3,3-bis (p-dimethylaminophenyl) -6
-Dimethylaminophthalide (also known as crystal violet lactone), 3,3-bis (p-dimethylaminophenyl)
-6-diethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-
Dibutylaminophenyl) phthalide, 3-cyclohexylamino-6-chlorofluorane, 3-dimethylamino-5,
7-Dimethylfluorane, 3-N-methyl-N-isobutyl-6-
Methyl-7-anilinofluorane, 3-N-ethyl-N-isoamyl-6-methyl-7-anilinofluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3- (Np-tolyl-N-ethylamino) -6-
Methyl-7-anilinofluorane, 3-pyrrolidino-6-
Methyl-7-anilinofluorane, 2- {N- (3'-trifluoromethylphenyl) amino} -6-diethylaminofluorane, 2- {3,6-bis (diethylamino) -9- (o-
Chloranilino) xanthylbenzoic acid lactam}, 3-diethylamino-6-methyl-7- (m-trichloromethylanilino) fluorane, 3-diethylamino-7- (o-chloroanilino) fluorane, 3-dibutylamino-7- (o -Chloranilino) fluorane, 3-N-methyl-N-amylamino-6-methyl-7-anilinofluorane, 3-N-methyl-N
-Cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7- (2 ', 4'-dimethylanilino ) Fluoran, 3- (N, N-diethylamino) -5
-Methyl-7- (N, N-dibenzylamino) fluorane, benzoyl leuco methylene blue, 6'-chloro-8'-methoxy-benzoindolino-spiropyran, 6'-bromo-
3'-methoxy-benzoindolino-spiropyran, 3-
(2'-hydroxy-4'-dimethylaminophenyl) -3-
(2'-methoxy-5'-chlorophenyl) phthalide, 3- (2 '
-Hydroxy-4'-dimethylaminophenyl) -3- (2 '
-Methoxy-5'-nitrophenyl) phthalide, 3- (2'-
Hydroxy-4'-diethylaminophenyl) -3- (2'-
Methoxy-5'-methylphenyl) phthalide, 3- (2'-methoxy-4'-dimethylaminophenyl) -3- (2'-hydroxy-4'-chloro-5'-methylphenyl) phthalide, 3
-Morpholino-7- (N-propyl-trifluoromethylanilino) fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7- (N-benzyl-trifluoromethyl) Anilino) fluorane, 3-pyrrolidino-7- (di-p-chlorophenyl)
Methylaminofluorane, 3-diethylamino-5-chloro-
7- (α-phenylethylamino) fluorane, 3- (N-ethyl
-p-toluidino) -7- (α-phenylethylamino) fluorane, 3-diethylamino-7- (o-methoxycarbonylphenylamino) fluorane, 3-diethylamino-5-methyl-7-
(α-Phenylethylamino) fluorane, 3-diethylamino-7-piperidinofluorane, 2-chloro-3- (N-methyltoluidino) -7- (pn-butylanilino) fluorane, 3-
(N-methyl-N-isopropylamino) -6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3,6-bis (dimethylamino) fluorene spiro ( 9,3 ')-6'-Dimethylaminophthalide, 3- (N-benzyl-N-cyclohexylamino) -5,6-benzo-7-α
-Naphthylamino-4'-bromofluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3-N-ethyl-N
-(2-Ethoxypropyl) amino-6-methyl-7-anilinofluorane, 3-N-ethyl-N-tetrahydrofurfurylamino-6-methyl-7-anilinofluorane, 3-diethylamino
-6-methyl-7-mesitidino-4 ', 5'-benzofluorane, 3-
(p-Dimethylaminophenyl) -3- {1,1-bis (p-dimethylaminophenyl) ethylene-2-yl} phthalide, 3- (p-dimethylaminophenyl) -3- {1,1-bis ( p-dimethylaminophenyl) ethylene-2-yl} -6-dimethylaminophthalide,
3- (p-dimethylaminophenyl) -3- (1-p-dimethylaminophenyl-1-phenylethylene-2-yl) phthalide, 3- (p-
Dimethylaminophenyl) -3- (1-p-dimethylaminophenyl-1-p-chlorophenylethylene-2-yl) -6-dimethylaminophthalide, 3- (4'-dimethylamino-2'-methoxy)-
3- (1 ''-p-dimethylaminophenyl-1 ''-p-chlorophenyl-1 '', 3 ''-butadiene-4 ''-yl) benzophthalide, 3-
(4'-Dimethylamino-2'-benzyloxy) -3- (1 ''-p-dimethylaminophenyl-1 ''-phenyl-1 '', 3 ''-butadiene-4 ''-yl) benzophthalide , 3-dimethylamino-6-dimethylamino-fluorene-9-spiro 3 '(6'-dimethylamino) phthalide, 3,3-bis {2- (p-dimethylaminophenyl) -2- (p-methoxyphenyl ) Ethenyl} -4,5,6,7-tetrachlorophthalide, 3-bis {1,1-bis (4-pyrrolidinophenyl) ethylene-2-yl} -5,6-dichloro-4,7- Dibromophthalide, bis (p-dimethylaminostyryl) -1-naphthalenesulfonylmethane, bis (p-dimethylaminostyryl) -1
-p-tolylsulfonylmethane, 2- (3-methylanilino) -3-methyl-6- (N-methyl-N-isopentylamino) fluorane, 2- (3-methylanilino) -3-
Methyl-6- (N-ethyl-N-isopentylamino)
Fluoran, 2- (3-methylanilino) -3-methyl-6
-(N-n-propyl-N-isopentylamino) fluorane, 2- (3-methylanilino) -3-methyl-6-
(Nn-butyl-N-isopentylamino) fluorane, 2- (3-methylanilino) -3-methyl-6-di-n
-Pentylaminofluorane, 2- (3-methylanilino) -3-methyl-6- (N-ethyl-N-neopentylamino) -fluorane, 2- (3-methylanilino) -3
-Methyl-6-di-n-propylaminofluorane, 2-
(3-methylanilino) -3-methyl-6-dimethylaminoflurane and the like.

As the color developer used in the thermosensitive color developing layer of the present invention, various electron-accepting compounds that cause the leuco dye to develop color upon contact, such as phenolic compounds, thiophenolic compounds, thiourea derivatives, and organic compounds. Acids and metal salts thereof are preferably applied, and specific examples thereof include those shown below.

4,4'-isopropylidene bisphenol,
4,4'-isopropylidene bis (o-methylphenol),
4,4'-Secondary butylidene bisphenol 4,4'-isopropylidene bis (2-tert-butylphenol), 4,4'-cyclohexylidene diphenol, 4,4'-
Isopropylidene bis (2-chlorophenol), 2,2'-
Methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 4,4'-butylidenebis (6-tert-butyl-2-methylphenol), 1 , 1,3-Tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,1,3-Tris (2-methyl-4-hydroxy-
5-cyclohexylphenyl) butane, 4,4'-thiobis (6
-Tert-butyl-2-methylphenol), 4,4'-
Diphenol sulfone, 4-isopropoxy-4'-hydroxydiphenyl sulfone, 4-benzyloxy-4'-hydroxydiphenyl sulfone, 4,4'-diphenol sulfoxide, isopropyl P-hydroxybenzoate, benzyl P-hydroxybenzoate , Benzyl protocatechuate, stearyl gallate, lauryl gallate, octyl gallate, 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane, 1,5-bis (4-hydroxyphenylthio) -3-Oxapentane, 1,3-bis (4-hydroxyphenylthio) -propane, 1,3-bis (4-hydroxyphenylthio) -2-hydroxypropane, N, N'-diphenylthiourea, N, N'-di (m-chlorophenyl) thiourea, salicylanilide, 5-chloro-salicylanilide, 2-hydroxy-3-naphthoic acid, 2-hydroxy-1- Futoe acid, 1-hydroxy-2-naphthoic acid, zinc hydroxynaphthoic acid, aluminum, metal salts such as calcium,
Bis- (4-hydroxyphenyl) acetic acid methyl ester, bis- (4-hydroxyphenyl) acetic acid benzyl ester, 1,3
-Bis (4-hydroxycumyl) benzene, 1,4-bis (4-
(Hydroxycumyl) benzene, 2,4'-diphenol sulfone, 3,3'-diallyl-4,4'-diphenol sulfone,
α, α-bis (4-hydroxyphenyl) -α-methyltoluene, zinc thiocyanate antipyrine complex, tetrabromobisphenol A, tetrabromobisphenol S, 4,
4'-thiobis (2-methylphenol), 4,4'-thiobis (2-
Chlorophenol) etc.

In order to produce the heat-sensitive recording material of the present invention,
When the leuco dye and the color developer are bound and supported on the support, various commonly used binders can be appropriately used, and specific examples thereof include the following.

Polyvinyl alcohol, starch and its derivatives, cellulose derivatives such as hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose and ethyl cellulose, polyacrylic acid sodium -Da, polyvinylpyrrolidone, acrylamide / acrylic acid ester copolymer, acrylamide / acrylic acid ester / methacrylic acid terpolymer, styrene /
Maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, polyacrylamide, soda alginate, gelatin, other water-soluble polymers such as casein, polyvinyl acetate, polyurethane, polyacrylic acid, Polyacrylic acid ester, vinyl chloride / vinyl acetate copolymer, polybutyl methacrylate, ethylene /
Emulsion such as vinyl acetate copolymer, latex such as styrene / butadiene copolymer and styrene / butadiene / acrylic copolymer.

Further, in the present invention, various heat-fusible substances can be used as the sensitivity improver, and specific examples thereof include the followings, but the present invention is not limited thereto. . Fatty acids such as stearic acid and behenic acid, fatty acid amides such as stearic acid amide and palmitic acid amide, fatty acid metal salts such as zinc stearate, aluminum stearate, calcium stearate, zinc palmitate and zinc behenate, p-benzyl Biphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, phenyl β-naphthoate, phenyl 1-hydroxy-2-naphthoate, methyl 1-hydroxy-2-naphthoate, diphenyl Carbonate, Greacol Carbonate, Dibenzyl terephthalate, Dimethyl terephthalate, 1,4-Dimethoxynaphthalene, 1,4-Diethoxynaphthalene, 1,4-Dibenzyloxynaphthalene, 1,2-Diphenoxyethane, 1,2 -
Bis (3-methylphenoxy) ethane, 1,2-bis (4-methylphenoxy) ethane, 1,4-diphenoxy-2-butene, 1,2-
Bis (4-methoxyphenylthio) ethane, dibenzoylmethane, 1,4-diphenylthiobutane, 1,4-diphenylthio
-2-butene, 1,3-bis (2-vinyloxyethoxy) benzene, 1,4-bis (2-vinyloxyethoxy) benzene, p- (2
-Vinyloxyethoxy) bifer, p-aryloxypphenyl, p-propargyloxybiphenyl, dibenzoyloxymethane, dibenzoyloxypropane, dibenzyl disulfide, 1,1-diphenylethanol, 1,1-diphenylpropanol, p -Benzyloxybenzyl alcohol, 1,3-phenoxy-2-propanol, N-octadecylcarbamoyl-p-methoxycarbonylbenzene, N-
Octadecylcarbamoylbenzene, 1,2-bis (4-methoxyphenoxy) propane, 1,5-bis (4-methoxyphenoxy) -3-oxapentane, dibenzyl oxalate, bis (4-methylbenzyl) oxalate, oxalic acid Bis (4-chlorobenzyl) and the like.

As the pigment, inorganic pigments and organic pigments may be used alone or in combination of two or more. As the inorganic pigment, an oil supply amount of 30 ml / 100 g or more is selected. These inorganic pigments can be selected from pigments commonly used in this type of heat-sensitive recording material, for example, calcium carbonate, silica, zinc oxide, titanium oxide,
Inorganic pigments such as aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, surface-treated calcium and silica, kaolin, calcined kaolin and colloidal silica can be mentioned. Further, as the organic pigment, for example,
Examples thereof include urea-formalin resin, styrene / methacrylic acid copolymer, polystyrene resin, vinylidene chloride resin and the like. If necessary, other lubricants such as the paraffin wax and the metal salt of stearic acid, for example, higher fatty acid and metal salt thereof, higher fatty acid amide, higher fatty acid ester, animal, vegetable, mineral or petroleum type are used. Waxes and the like can also be included.

In the present invention, an intermediate layer may be provided between the support and the thermosensitive color developing layer, if necessary. In this case, as the component forming the intermediate layer, the above-mentioned pigment, binder, heat-fusible substance and the like can be used, and in addition, hollow body fine particles can be contained. Various hollow body fine particles are used, and examples thereof include hollow body fine particles formed of a material such as glass, ceramics, plastics, and the like. Particularly, the hollowness rate of a thermoplastic resin is 1
Hollow particles of 0% or more are preferred. Further, in the present invention, a protective layer may be provided on the thermosensitive coloring layer, if necessary. In this case, as the component constituting the protective layer, the above-mentioned pigment, binder, lubricant, etc. can be used in addition to the paraffin wax and the metal stearate salt.

[0023]

Since the heat-sensitive recording material of the present invention has the above-mentioned constitution, it does not cause head-up / down stains, band-like stains and vertical ruled line deviations when printed by a serial printing type printer.

[0024]

EXAMPLES Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples. All parts and% shown below are based on weight.

Example 1 [Solution A] 3-dibutylamino-6-methyl-7-anilinofluorane 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts water 60 parts [Solution B] 2,2-bis (4-) Hydroxyphenyl) propane 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts water 60 parts A mixture of the above composition is dispersed using a sand mill so that the average particle size is 1.5 μm or more and 2.0 μm or less, and ], And [B liquid] were adjusted. [Liquid C] [Liquid A] 10 parts [Liquid B] 30 parts 7 parts of paraffin wax dispersion (concentration 30%) whose melting start temperature of endothermic peak obtained by differential thermal analysis of solid is 63.5 ° C ( Chukyo Yushi Hydrin E-139) Zinc stearate dispersion having an average particle size of 4 μm (concentration 30%) 7 parts (Chukyo Yushi Hydrin Z-730) 10% aqueous solution of polyvinyl alcohol 10 parts A mixture comprising the above composition The mixture was thoroughly stirred to adjust [C liquid]. Here, the differential thermal analysis of the solid content of the paraffin wax dispersion was carried out by a thermal analyzer system 001 DSC-3100 manufactured by Mac Science Co., Ltd. The analysis was performed by reading the melting start temperature from the endothermic peak of the DSC curve obtained by raising 6 mg of the wax solid matter from 30 ° C. to 120 ° C. at a heating rate of 20 ° C./min under a nitrogen stream. . The average particle size of the stearic acid metal salt and aluminum hydroxide is measured using a laser diffraction / scattering particle size distribution measuring device LA-700 manufactured by Horiba, Ltd. Commercially available high-quality paper (5
8 g / m ² ) on the surface so that the weight after drying is 6 g / m ^2, and the surface has a smoothness of 500 to 2000.
The heat-sensitive recording material of the present invention was obtained by carrying out a calendering treatment so that the time became seconds.

Example 2 [D liquid] 10% aqueous solution of polyvinyl alcohol 50 parts 25% aqueous dispersion of aluminum hydroxide (average particle size: 2 μm) 25 parts Chukyo Yushi Hydrin Z-730 5 parts water 20 parts Example In the same manner as in Example 1, except that after applying and drying [C liquid], [D liquid] was further applied and dried so that the weight after drying was 0.5 g / m ² . A thermosensitive recording material was obtained.

Comparative Example 1 A thermosensitive recording material was obtained in the same manner as in Example 1, except that a paraffin wax dispersion (Hydrin P-7) manufactured by Chukyo Yushi Co., Ltd. was used instead of the hydrin E-139 manufactured by Chukyo Yushi Co., Ltd. . The melting start temperature of the endothermic peak obtained by the differential thermal analysis of the solid content of hydrin P-7 was 43.4 ° C.

Comparative Example 2 A thermal recording material was prepared in the same manner as in Example 1, except that Hydrin F-115 (average particle size: 0.2 μm) manufactured by Chukyo Yushi Co., Ltd. was used in place of Hydrin Z-730 manufactured by Chukyo Oil and fat. Obtained.

Comparative Example 3 A thermosensitive recording material was obtained in the same manner as in Example 1, except that the following [solution E] (concentration: 33%) was used instead of Hydrin Z-730 manufactured by Chukyo Yushi Co., Ltd. [Liquid E] Zinc stearate 100 parts 5% aqueous solution of methyl cellulose 200 parts water 33 parts A mixture of the above composition dispersed by a sand mill so that the average particle diameter becomes 1.5 μm.

Comparative Example 4 A thermosensitive recording material was obtained in the same manner as in Example 1, except that the following [F liquid] (concentration: 33%) was used instead of Hydrin Z-730 manufactured by Chukyo Yushi. [F liquid] A mixture of the same composition as that of [E liquid] dispersed in a sand mill so that the average particle diameter is 12 μm.

The heat-sensitive recording material obtained as described above is used as a word processor having a serial printer.
Characters and vertical ruled lines were printed using Ricoh My Report NT-500, and the states of head-up / down stains, band-like stains and vertical ruled line shifts were observed, and the results are summarized in Table 1.

[0032]

[Table 1] ○… Head up / down dirt, band-like dirt, vertical ruled line deviation did not occur △… Head-up / down dirt, band-like dirt, vertical ruled line deviation slightly occurred ×… Head-up / down dirt, band-like dirt , Vertical ruled lines are misaligned

As described above, the heat-sensitive recording material of the present invention is
It was practically excellent, with no head-up / down stains, band-like stains, and vertical ruled line shifts.

Claims (3)

[Claims] 1. A heat-sensitive recording material comprising a support and a heat-sensitive color-forming layer containing an electron-donating colorless dye and an electron-accepting developer, wherein the heat-sensitive color-developing layer has an endotherm obtained by differential thermal analysis. A thermosensitive recording material comprising a paraffin wax having a peak melting start temperature of 60 ° C. or higher and a stearic acid metal salt having an average particle diameter of 2 to 10 μm. 2. The heat-sensitive recording material according to claim 1, wherein the metal stearate is zinc stearate. 3. The recording method of the heat-sensitive recording material according to claim 1 or 2, wherein heat-sensitive recording is performed on the heat-sensitive recording material by a serial printer type heat-sensitive printer.