JPH09202049A - Thermal recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermal recording material provided less ground fogging and superior heat resistance, light resistance and water resistance of a recording sensitivity and a recording image. SOLUTION: This recording material is constituted so as to provide a recording layer containing a leuco dye and a coloration agent on a support. In this case, 4,4'-cyclohexylydenediphenol and 2-(2'-hydroxy-5'-methylphenyl) benzotriazole are contained in the recording layer. Then, at least one of 1, 1,3-tris(2-methyl-4-hydroxy-5-cyclohexylphenyl)butane or 1-[α-methyl-α-(p- hydroxyphenyl)ethyl]-4-[α',α-bis(p-hydroxyphenyl)ethyl] benzene is contained.

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 utilizing a color-forming reaction between a leuco dye and a color former, and more particularly to a heat-sensitive recording material excellent in recording sensitivity and storability of recorded images.

[0002]

2. Description of the Related Art A thermosensitive recording medium is well known in which a coloring image of a leuco dye and a coloring agent is utilized to bring both substances into contact with each other by heat to obtain a recorded image. Since such a thermal recording medium is relatively inexpensive, the recording device is compact, and its maintenance is easy, it is used not only as a recording medium for facsimiles and various computers but also in a wide range of fields.

[0003] For example, POS (Point of sal
es) With the expansion of systemization, the number of cases where the thermal recording material is used as a label for displaying products is increasing. A thermal recording material for a label attached to a product generally has insufficient storage stability of a recorded image and has a problem of fading over time. In particular, since the recorded image disappears in a relatively short time under the condition of high temperature (50 to 90 ° C.) or when immersed in water, improvement thereof is strongly demanded.

Further, it has been proposed to add a heat-fusible substance (sensitizer) having a low melting point to the recording layer in order to increase the recording sensitivity of the thermosensitive recording medium in combination with the increase in recording speed. Although the recording sensitivity is increased by adding a heat-fusible substance having a low melting point, there is a problem that the background fog is likely to occur and the heat-resistant storage stability of a recorded image is lowered. In order to improve the heat resistant storage stability of a recorded image, for example, 3-di (n-butyl) amino-6 is used.
It has been proposed to add two types of fusible substances having a low melting point to -methyl-7-anilinofluorane (JP-A-1-281983), but there is a problem in the storability of recorded images.

In order to improve the storage stability of recorded images, 4,4'-cyclohexylidenediphenol and 1,1,3-tris (2-methyl-4-hydroxy-5) are added to the recording layer.
Japanese Patent Application Laid-Open No. 2-286395 discloses a method of incorporating 2-cyclohexylphenyl) butane. In order to enhance recording sensitivity, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole is incorporated into the recording layer. Although the method is disclosed in JP-A-58-87093, the present situation is that a method excellent in recording sensitivity and storability of recorded images has not been obtained.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermosensitive recording medium which has less background fog and is excellent in recording sensitivity and heat resistance, light resistance and water resistance of recorded images.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a thermosensitive recording medium in which a recording layer containing a leuco dye and a color former is provided on a support, and 4,4'-cyclohexylidene diene is contained in the recording layer. Phenol and 2- (2'-hydroxy-5'-
Methylphenyl) benzotriazole is contained, and 1,1,3-tris (2-methyl-4-hydroxy-5) is further contained.
-Cyclohexylphenyl) butane or 1- [α-methyl-α- (p-hydroxyphenyl) ethyl] -4-
By containing at least one of [α ', α'-bis (p-hydroxyphenyl) ethyl] benzene, the above problems have been solved and completed.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is a thermosensitive recording medium in which a recording layer containing a leuco dye and a coloring agent is provided on a support, and 4,4'-cyclohexylidenediphenol is contained in the recording layer. Specific colorant and 2- (2'-hydroxy-
5'-methylphenyl) benzotriazole is contained as a specific ultraviolet absorber, and further 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane or 1- [α-methyl- α- (p
-Hydroxyphenyl) ethyl] -4- [α ', α'-
Bis (p-hydroxyphenyl) ethyl] benzene, which is characterized by containing at least one kind of a specific storage stability improving agent. By using such a specific coloring agent and a specific ultraviolet absorber in combination, The occurrence of background fog is small, and the light resistance of a recorded image and the recording sensitivity are remarkably improved, and the water resistance of a recorded image is improved by using a specific storage stability improver together.

In the heat-sensitive recording material of the present invention, the use ratio of the specific coloring agent, the specific ultraviolet absorber and the specific storage stability improving agent is not particularly limited, but generally 100 parts by weight of the leuco dye is used. On the other hand, a specific coloring agent
0 to 700 parts by weight, preferably 150 to 500 parts by weight,
10 to 700 parts by weight, preferably 50 to 500 parts by weight of a specific ultraviolet absorber, 10 to 50 parts by weight of a specific storage stability improver
The amount is 0 parts by weight, preferably about 10 to 300 parts by weight.

The leuco dye contained in the recording layer is not particularly limited, and various known ones can be used. Specific examples of such leuco dyes include, for example, 3,3
-Bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-methylphenyl) -3- (4-dimethylaminophenyl)-
6-dimethylaminophthalide, 3-diethylamino-7
Blue-coloring dyes such as -dibenzylamino-benzo [a] fluoran, 3- (N-ethyl-N-p-tolyl) amino-7-N-methylanilinofluoran, 3-diethylamino-7-anilino Fluoran, 3-diethylamino-
Green coloring dye such as 7-dibenzylaminofluorane, 3
-Cyclohexylamino-6-chlorofluoran, 3-
Diethylamino-6-methyl-7-chlorofluorane,
3-diethylamino-7-chlorofluorane, rhodamine (o-chloroanilino) lactam, 3-diethylamino-7,8-benzofluorane, 3- (N-ethyl-p
-Toluidino) -7-methylfluorane, 3-diethylamino-6,8-dimethylfluorane, 3,3'-bis (1-n-butyl-2-methylindol-3-yl)
Red coloring dye such as phthalide,

3-di (n-butyl) amino-6-methyl-7-anilinofluorane, 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluorane, 3- (N-methyl-N-cyclohexyl) amino-
6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-di (n-butyl) amino-7- (o-chloroanilino) fluorane, 3-di (n -Pentyl) amino-6-methyl-7-anilinofluorane, 3-diethylamino-7-
(O-chlorophenylamino) fluoran, 3-diethylamino-7- (o-fluorophenylamino) fluoran, 3-di (n-butyl) amino-7- (o-fluorophenylamino) fluoran, 3- (N-ethyl -P
-Toluidino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluorane, 3-diethylamino-6-chloro-7 -Anilino Fluoran,
3- (N-methyl-Nn-propylamino) -6-methyl-7-anilinofluorane, 3-dimethylamino-
6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-p-ethoxyanilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-piperidino-6- Black color-forming dyes such as methyl-7-anilinofluorane and 3-diethylamino-7- (3'-trifluoromethylphenyl) aminofluorane,

3,3-bis [1- (4-methoxyphenyl) -1- (4-dimethylaminophenyl) ethylene-
2-yl] -4,5,6,7-tetrachlorophthalide,
3,3-bis [1- (4-methoxyphenyl) -1-
(4-pyrrolidinophenyl) ethylene-2-yl]-
4,5,6,7-Tetrachlorophthalide, 3,3-bis [1,1-bis (4-pyrrolidinophenyl) ethylene-
2-yl] -4,5,6,7-tetrabromophthalide,
3-p- (p-dimethylaminoanilino) anilino-6
-Methyl-7-chlorofluorane, 3-p- (p-chloroanilino) anilino-6-methyl-7-chlorofluorane, 3,6-bis (dimethylamino) fluorene-9
Examples thereof include dyes having an absorption wavelength in the near infrared region such as -spiro-3 '-(6'-dimethylamino) phthalide.
Of course, it is not limited to these, and two or more kinds may be used in combination as required. The amount of the leuco dye used is not particularly limited, but is about 5 to 40% by weight, preferably about 10 to 30% by weight based on the total solid amount of the recording layer.

Although 4,4'-cyclohexylidenediphenol is used as a coloring agent together with the above leuco dye, other known coloring agents may be used as long as the desired effects of the present invention are not impaired. It can also be used together. Specific examples of such a coloring agent include 4,4′-isopropylidenediphenol, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 4,4′-dihydroxydiphenyl sulfide and hydroquinone monobenzyl ether. , Benzyl 4-hydroxybenzoate, 4,4'-dihydroxydiphenyl sulfone, 4-hydroxy-4 '
-Isopropoxydiphenyl sulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxy-4'-methyldiphenyl sulfone, 4-hydroxyphenyl-4'-benzyloxyphenyl sulfone,
3,4-dihydroxyphenyl-4′-methylphenyl sulfone, 1,4-bis [α-methyl-α- (4′-hydroxyphenyl) ethyl] benzene, 1,3-bis [α-methyl-α- ( 4'-hydroxyphenyl) ethyl] benzene, di (4-hydroxy-3-methylphenyl) sulfide, 2,2'-thiobis (3-tert-octylphenol), 2,2'-thiobis (4-tert-octylphenol) Phenolic compounds such as N, N '
-Thiourea compounds such as di-m-chlorophenylthiourea, N- (p-tolylsulfonyl) carbamoyl acid-p
-Cumylphenyl ester, N- (p-tolylsulfonyl) carbamoyl acid-p-benzyloxyphenyl ester, N- (o-toluoyl) -p-tolylsulfoamide, N- (p-tolylsulfonyl) -N'- (P-tolyl) urea, 4,4′-bis (Np-tolylsulfolaminocarbonylamino) diphenylmethane and the like having a —SO ₂ NH— bond in the molecule, zinc p-chlorobenzoate, 4- Zinc [2- (p-methoxyphenoxy) ethyloxy] salicylate, Zinc 4- [3- (p-tolylsulfonyl) propyloxy] salicylate, 5- [p-
Examples include zinc (2-p-methoxyphenoxyethoxy) cumyl] aromatic carboxylic acid such as zinc salicylate and zinc dithiosalicylate.

In the present invention, the recording layer further contains 2- (2'-hydroxy-5'-methylphenyl) benzotriazole as an ultraviolet absorber, whereby the light resistance of the recorded image and the background fog are reduced. Moreover, the effect of remarkably increasing the recording sensitivity can be obtained. Further, various known sensitizers may be used in combination for increasing the recording sensitivity. Specific examples of the sensitizer include stearic acid amide, ethylenebisstearic acid amide, methylenebisstearic acid amide, N-methylolstearic acid amide, dibenzyl terephthalate, benzyl p-benzyloxybenzoate, and 2-naphthylbenzyl. Ether, m
-Terphenyl, p-benzylbiphenyl, di (p-methoxyphenoxyethyl) ether, 1,2-di (3-
Methylphenoxy) ethane, 1,2-di (4-methylphenoxy) ethane, 1,2-di (4-methoxyphenoxy) ethane, 1,2-di (4-chlorophenoxy) ethane, 1,2-diphenoxy Ethane, 1- (4-methoxyphenoxy) -2- (3-methylphenoxy) ethane,
p-methylthiophenylbenzyl ether, 1,4-di (phenylthio) butane, p-acetotoluidide, p-
Acetophenetide, N-acetoacetyl-p-toluidine, di (β-biphenylethoxy) benzene, p-di (vinyloxyethoxy) benzene, 1-isopropylphenyl-2-phenylethane, 2-naphthylbenzyl ether, Shu Acid di-p-chlorobenzyl ester,
Examples thereof include oxalic acid di-p-methylbenzyl ester and oxalic acid dibenzyl ester.

To improve the water resistance of the recorded image, 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane or 1-, 1
[Α-Methyl-α- (p-hydroxyphenyl) ethyl] -4- [α ', α'-bis (p-hydroxyphenyl) ethyl] benzene is contained in at least one type of compound, which is desirable in the present invention. As long as the effect of the above is not impaired, other various known storage stability improvers can be used in combination, and specific examples of the storage stability improver include, for example, 2,
2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6)
-Tert-butylphenol), 2,2'-ethylidenebis (4,6-di-tert-butylphenol), 4,4 '
-Thiobis (2-methyl-6-tert-butylphenol), 4,4'-butylidenebis (6-tert-butyl-
m-cresol), 1,1,3-tris (2-methyl-)
4-hydroxy-5-tert-butylphenyl) butane,
4,4'-thiobis (3-methylphenol), 2,2
-Bis (4-hydroxy-3,5-dichlorophenyl)
Hindered phenol compounds such as propane and 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 4,4′-diglycidyloxydiphenyl sulfone, 4-benzyloxy-4 ′-(2-methyl Glycidyloxy) diphenyl sulfone, diglycidyl terephthalate, cresol novolac type epoxy resin, phenol novolac type epoxy resin, bisphenol A type epoxy resin and other epoxy compounds, N, N′-di-2-naphthyl-p-phenylenediamine, 2, Examples thereof include sodium or polyvalent metal salt of 2'-methylenebis (4,6-di-tert-butylphenyl) phosphate, bis (4-ethyleneiminocarbonylaminophenyl) methane and the like.

The recording coating liquid containing these leuco dyes, specific color formers, specific storability improvers, specific ultraviolet absorbers and the like generally uses water as a dispersion medium and is prepared by using a ball mill, attritor, sand mill or the like. It is prepared by finely dispersing a leuco dye, a specific coloring agent, a specific storability improving agent, and a specific ultraviolet absorber together or separately with a stirrer / pulverizer, and then adding the following adhesive and the like.

Examples of the adhesive include starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, polyvinyl alcohol, carboxy modified polyvinyl alcohol, acetoacetyl group modified polyvinyl alcohol, silicon modified polyvinyl alcohol and diisobutylene. Maleic anhydride copolymer salt, styrene / maleic anhydride copolymer salt, ethylene / acrylic acid copolymer salt, styrene / acrylic acid copolymer salt, styrene / butadiene copolymer emulsion, urea resin, melamine resin, At least one of amide resins and polyurethane resins can be used. The amount of such an adhesive used is about 5 to 30% by weight based on the total solid content of the recording layer.

If desired, various auxiliaries can be added to the coating liquid for the recording layer. For example, sodium dioctyl sulfosuccinate, sodium dodecylbenzene sulfonate, sodium lauryl alcohol sulfate, fatty acid metal salt, etc. The dispersant, zinc stearate, calcium stearate, waxes such as polyethylene wax, carnauba wax, paraffin wax, ester wax, defoaming agent, coloring dye, and the following pigments are appropriately added.

Examples of pigments include kaolin, clay,
Examples thereof include inorganic pigments such as calcium carbonate, calcined clay, calcined kaolin, titanium oxide, diatomaceous earth, and amorphous silica, and organic pigments such as styrene microballs, nylon powder, polyethylene powder, urea / formalin resin filler, and raw starch particles.

In the heat-sensitive recording material of the present invention, a protective layer may be provided on the recording layer for the purpose of improving the storability of a recorded image with respect to chemicals such as plasticizers and oils, or the recording suitability. The method for preparing the protective layer coating liquid for forming the protective layer is not particularly limited, and generally water as a dispersion medium, starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, polyvinyl. Prepared by mixing and stirring a film-forming adhesive such as alcohol, carboxy-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, or silicon-modified polyvinyl alcohol with a pigment such as kaolin, light calcium carbonate or amorphous silica. .

Further, in the coating liquid for protective layer, if necessary, a lubricant such as zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax, ester wax, etc., and a surfactant (dispersion such as sodium dioctylsulfosuccinate) (dispersion). Agent, wetting agent), defoaming agent,
Various auxiliaries such as water-soluble polyvalent metal salts such as potassium alum and aluminum acetate may be appropriately added. Further, in order to further improve the water resistance, a curing agent such as glyoxal, boric acid, dialdehyde starch, and an epoxy compound can be used in combination.

The method for forming the recording layer and the protective layer is not particularly limited, and suitable coating such as air knife coating, varibar blade coating, pure blade coating, rod blade coating, short dwell coating, curtain coating, die coating, etc. The coating liquid for recording layer is applied and dried on the support by a method, and then the coating liquid for protective layer is further applied and dried on the recording layer. The support may be appropriately selected from paper, plastic film, synthetic paper, non-woven fabric, metal deposit, etc., and used. Also,
The coating amount of the recording layer coating liquid is ² to 12 g / m ^{2 as} a dry weight,
Preferably 3 to 10 g / m ² approximately, 0.5 to 15 g / m ² coating amount of the protective layer coating liquid for a dry weight, preferably 1.
It is adjusted within the range of 0 to 8 g / m ² .

If necessary, a protective layer may be provided on the back side of the thermosensitive recording medium to further improve the storability, an undercoat layer may be provided between the support and the recording layer, and a super calendar after coating each layer. Applying a smoothing treatment such as hanging, or applying an adhesive treatment to the back surface of the thermal recording medium to process it into an adhesive label, rewetting adhesive layer, magnetic recording layer, printing coating layer and thermal transfer recording layer. Various known techniques in the field of thermal recording material production, such as provision, can be added as necessary.

[0024]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In addition, unless otherwise indicated, the part and% in an example show a weight part and weight%, respectively.

Example 1 Preparation of solution A 1 part of 2- (2'-hydroxy-5'-methylphenyl) benzotriazole 40 parts, polyvinyl alcohol [trade name: Go-Celan L-3266, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.]
A composition consisting of 40 parts of a 0% aqueous solution and 20 parts of water was dispersed in a vertical sand mill until the particle size became 1.3 μm.

Preparation of solution B 10 parts of 3-di (n-butyl) amino-6-methyl-7-anilinofluorane, 5% aqueous solution of methylcellulose 5
Parts and 40 parts of water were pulverized with a sand mill until the average particle diameter became 1 μm.

Preparation of liquid C A composition consisting of 30 parts of 4,4'-cyclohexylidenediphenol, 5 parts of a 5% aqueous solution of methylcellulose and 70 parts of water was pulverized in a sand mill until the average particle diameter became 2 μm, and then the conditions of 60 ° C. It was left standing for 1 day.

Preparation of Solution D 1,1,3-Tris (2-methyl-4-hydroxy-5)
A composition consisting of 30 parts of -cyclohexylphenyl) butane, 5 parts of a 5% aqueous solution of methylcellulose, and 55 parts of water was pulverized with a sand mill until the average particle size became 1 µm.

Preparation of Coating Liquid for Recording Layer A liquid 34 parts, B liquid 75 parts, C liquid 122 parts, D liquid 28 parts,
170 parts of a 10% aqueous solution of polyvinyl alcohol, 3 parts of a 40% aqueous solution of glyoxal and 4 parts of aluminum hydroxide were mixed and stirred to obtain a coating liquid for a recording layer.

Preparation of Coating Liquid for Protective Layer 195 parts of 10% aqueous solution of polyvinyl alcohol modified with acetoacetyl group, 40 parts of aluminum hydroxide having an average particle diameter of 1.0 μm, kaolin [trade name: UW-90, manufactured by EMC] 10 Parts, 16 parts of 30% zinc stearate dispersion,
Curing agent with a concentration of 30% [Product name: PA-800, Japan PM
Company C] A composition consisting of 0.7 part and 100 parts of water was mixed and stirred to obtain a coating liquid for protective layer.

The heat-sensitive on one side of the recording medium neutral paper making basis weight of 44 g / m ² of the recording layer coating solution and a protective layer coating liquid application amount after drying 5 g / m ² and 4g / m ² After that, a recording layer and a protective layer were formed by sequentially coating and drying so as to obtain a thermosensitive recording material.

Example 2 In the preparation of solution D of Example 1, 1,1,3-tris (2
1- [α-methyl-α-instead of 30 parts of methyl-4-hydroxy-5-cyclohexylphenyl) butane
(P-Hydroxyphenyl) ethyl] -4- [α ',
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that 30 parts of α'-bis (p-hydroxyphenyl) ethyl] benzene was used.

Example 3 In the preparation of solution B of Example 1, 3- (N-ethyl-p-toluidino) was used instead of 10 parts of 3-di (n-butyl) amino-6-methyl-7-anilinofluorane. ) A thermosensitive recording medium was obtained in the same manner as in Example 1 except that 10 parts of 6-methyl-7-anilinofluorane was used.

Comparative Example 1 A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the solution A was not used in the preparation of the recording layer coating solution of Example 1.

Comparative Example 2 A thermosensitive recording medium was obtained in the same manner as in Example 1 except that D liquid was not used in the preparation of the recording layer coating liquid of Example 1.

Comparative Example 3 In the preparation of the liquid A of Example 1, 40 parts of 1,2-bis (3-methylphenoxy) ethane was used instead of 40 parts of 2- (2'-hydroxy-5'-methylphenyl) benzotriazole. A thermosensitive recording medium was obtained in the same manner as in Example 1 except that was used.

Comparative Example 4 Example 1 was repeated except that 30 parts of 4,4′-isopropylidenediphenol was used in place of 30 parts of 4,4′-cyclohexylidenediphenol in the preparation of the liquid C of Example 1. A thermosensitive recording medium was obtained in the same manner as described above.

Comparative Example 5 In the preparation of the liquid D of Example 1, 1,1,3-tris (2
-Methyl-4-hydroxy-5-cyclohexylphenyl) butane was replaced with 30 parts of sodium salt of 2,2'-methylenebis (4,6-di-tert-butylphenyl) phosphate instead of 30 parts. A thermal recording material was obtained in the same manner as in Example 1.

The thermal recording material thus obtained was subjected to the following evaluation tests, and the results are shown in Table 1.

[Coloring property] Heat-sensitive evaluation machine [Product name: TH-P
MD, Okura Electric Co., Ltd.] applied energy 0.50 mJ
Each of the thermosensitive recording materials was made to develop color at a dot / dot, and the color density of the obtained recorded image was measured in a visual mode with a Macbeth densitometer [RD-914 type, manufactured by Macbeth Co.].

[Light resistance] The initial density of the background portion of the thermosensitive recording medium after recording in the above [Coloring property] and the background portion after irradiation with a xenon fade meter (manufactured by Suga Test Instruments Co., Ltd.) for 14 hours (xenon arc) The density was measured with a Macbeth densitometer (using a blue filter).

[High Temperature Resistance] The thermosensitive recording medium after recording in the above [coloring property] was left at 80 ° C. for 24 hours, and the color density and background density were measured with a Macbeth densitometer (visual mode). The high temperature resistance was evaluated.

[Water resistance] The thermosensitive recording medium after recording in the above [Color development] was immersed in tap water at 20 ° C. for 24 hours, and the color density was measured with a Macbeth densitometer (visual mode) to obtain water resistance. The sex was evaluated.

[0044]

[Table 1]

[0045]

As shown in [Table 1], the present invention is a heat-sensitive recording which has less background fog and is excellent in recording sensitivity and heat resistance, light resistance and water resistance of recorded images. It was a body.

Claims (1)

[Claims] 1. A thermosensitive recording medium comprising a support and a recording layer containing a leuco dye and a coloring agent, the recording layer comprising:
4,4'-cyclohexylidene diphenol and 2-
(2'-Hydroxy-5'-methylphenyl) benzotriazole is contained, and 1,1,3-tris (2-
Methyl-4-hydroxy-5-cyclohexylphenyl) butane or 1- [α-methyl-α- (p-hydroxyphenyl) ethyl] -4- [α ', α'-bis (p
-Hydroxyphenyl) ethyl] benzene.