JPH06247043A - Heat sensitive recording body - Google Patents

Abstract

PURPOSE:To provide a heat sensitive recording body whose color phase has a clear gold color. CONSTITUTION:In a heat sensitive recording body which is obtained by providing a heat sensitive recording layer containing colorless or light-colored basic dyes and colorant agent and a protective layer in order on a substrate, heat sensitive recording layer is formed of a coating liquid for the heat sensitive recording layer wherein a haze value becomes not exceeding 40 when 3g/m<2> of a heat sensitive recording layer is provided on a PET film having the haze value of not exceeding 2 and a thickness of 50mum and a layer containing fine powdery body of a Cu-Zn alloy is further provided between the substrate and heat sensitive recording 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 in which the background part has a golden color.

[0002]

2. Description of the Related Art A heat-sensitive recording material which utilizes a color reaction between a colorless or light-colored basic dye and an organic or inorganic color-forming agent to bring both color-forming substances into contact with each other by heat to obtain a recorded image is often used. Are known. Since such a thermosensitive 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.

One of the fields of use thereof is a thermosensitive recording medium for tags. Conventionally, the heat-sensitive recording material for a tag has a support, a heat-sensitive recording layer, a
Alternatively, a method of containing a colored dye or pigment in the protective layer is disclosed in Japanese Utility Model Publication No. 63-37252 and Japanese Utility Model Publication No. 63-6066.
No. 0, JP-A-1-133782, the inclusion of colored dyes or pigments in the heat-sensitive recording layer or protective layer lowers the recording sensitivity and the storability of recorded images. When a colored dye or pigment is contained in the support or between the support and the thermosensitive recording layer, the hue of the background becomes unclear due to the thermosensitive recording layer formed thereon.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material having a golden hue with a clear background hue.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have proposed a thermosensitive recording medium comprising a support, a thermosensitive recording layer containing a colorless or light-colored basic dye and a coloring agent, and a protective layer, which are provided in this order. The thermosensitive recording layer is formed of a coating liquid for a thermosensitive recording layer having a haze value of 2 or less and a haze value of 40 or less when the thermosensitive recording layer is provided on a PET film having a thickness of 50 μm at 3 g / m ² and further supported. It has been found that the above object can be achieved by providing a layer containing fine particles of a Cu—Zn alloy between the body and the heat-sensitive recording layer, and has completed the present invention.

[0006]

According to the present invention, by providing the layer containing the fine powder of the Cu--Zn alloy as described above, a thermal recording material having a golden hue with a high-grade background color can be obtained. With the fine powder of the Cu-Zn alloy used in the invention, a desired golden color can be obtained by changing the compounding ratio of zinc and copper. In order to obtain a fine powder of Cu-Zn based alloy of constant quality, high purity zinc and copper are used as raw materials.
For improving corrosion resistance, aluminum etc.
It is also possible to add 1% or color by heating. The content of zinc in the Cu—Zn alloy is 10 to 7
0%, preferably 20 to 55% is preferable. Cu-Zn
The fine particles of the base alloy have a particle size of 0.5 to 200 μm and an average thickness of 0.1 to 1.0 μm.

The layer containing the fine powder of Cu-Zn alloy is formed by finishing the fine powder of the alloy into an organic solvent-based paint or a water-based paint, and applying it to screen ink, gravure ink, offset ink, etc. It is provided on the front surface or the back surface of the support by finishing with printing ink and printing or the like.
The addition rate of the fine powder of the Cu-Zn alloy in the coating liquid or the ink is appropriately selected depending on the method of use, but is 0.01 to 90% by weight, preferably 0.1 to 60% by weight.
It is desirable to adjust in the range of weight%. Further, it is possible to add a fine powder of a Cu—Zn alloy to the undercoat layer, the heat-sensitive recording layer, the protective layer, etc. within a range not impairing the object of the present invention.

The heat-sensitive recording layer of the present invention has a haze value of 2 or less and 3 heat-sensitive recording layers on a PET film having a thickness of 50 μm.
It is formed from a coating liquid for a heat-sensitive recording layer, which has a haze value of 40 or less when provided in g / m ² . When the thermosensitive recording layer is formed on the layer containing the fine powder of the Cu-Zn alloy by the coating liquid for the thermosensitive recording layer having a haze value of more than 40, the hue of golden color becomes unclear due to irregular reflection of light. Further, the haze value of the heat-sensitive recording layer decreases when the thickness of the heat-sensitive recording layer is constant and the average particle diameter of the voids and the recording material becomes 1 μm or less, diffuse reflection of light is reduced. That is, the transparency of the heat-sensitive recording layer is increased and a clear golden hue is obtained. The thermal recording material of the present invention can also record a negative image and a positive image.

When colloidal silica or alumina sol is used as a pigment in the heat-sensitive recording layer, the number of voids in the heat-sensitive recording layer is decreased and the transparency of the heat-sensitive recording layer is increased. 5 to 40% by weight, preferably 10 to 30% by weight, based on the total solid content of
If it is less than 5% by weight, the transparency of the heat-sensitive recording layer is not improved so much, and if it exceeds 40% by weight, the recording density is lowered. As the average particle size of colloidal silica or alumina sol,
Particularly, 40 nm or less is preferable. Further, alumina sol made of boehmite is preferable because of its high transparency.

As the colorless or light-colored basic dye used in the heat-sensitive recording layer, various types are known, and examples thereof include the following. 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3,3
-Bis (p-dimethylaminophenyl) phthalide, 3-
(P-Dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl) fritado, 3- (p-dimethylaminophenyl) -3- (2-methylindole-
3-yl) fritado, 3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindole-3-)
Yl) -6-Dimethylaminophthalide, 3,3-bis (9-ethylcarbazol-3-yl) -6-dimethylaminophthalide, 3,3-bis (2-phenylindol-3-yl) -6 -Dimethylaminophthalide, 3-p
-Triarylmethane dyes such as dimethylaminophenyl-3- (1-methylpyrrol-3-yl) -6-dimethylaminophthalide, 4,4'-bis-dimethylaminobenzhydrylbenzyl ether, N-halophenyl −
Diphenylmethane dyes such as leuco auramine, N-2,4,5-trichlorophenyl leuco auramine, thiazine dyes such as benzoyl leuco methylene blue and p-nitrobenzoyl leuco methylene blue, 3-methyl-
Spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3-phenyl-spiro-dinaphthopyran, 3
-Spiro dyes such as benzyl-spiro-dinaphthopyran, 3-methyl-naphtho- (6'-methoxybenzo) spiropyran, 3-propyl-spiro-dibenzopyran, rhodamine-B anilinolactam, rhodamine (p-nitroanilino) lactam , Lactam dyes such as rhodamine (o-chloroanilino) lactam, 3-dimethylamino-7-methoxyfluorane, 3-diethylamino-6-
Methoxyfluorane, 3-diethylamino-7-methoxyfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6,7-dimethylfluorane, 3- (N-ethyl-p-toluidino) -7-methylfluorane, 3-diethylamino-7- (N-acetyl-N-methylamino) fluorane, 3-diethylamino-7-N-methylaminofluorane, 3 -Diethylamino-7-dibenzylaminofluorane, 3-diethylamino-7- (N-methyl-N-benzylamino) fluorane, 3-diethylamino-7- (N-chloroethyl-N-methylamino) fluorane, 3-diethylamino -7-diethylaminofluorane, 3-diethylamino-7- (m-to Fluoromethylanilino) fluorane, 3- (N-ethyl-p-toluidino) -6-methyl-7-phenylaminofluorane, 3- (N-cyclopentyl-N-ethylamino) -6-methyl-7-ani Rinofluorane, 3- (N-ethyl-p-toluidino)-
6-methyl-7- (p-toluidino) fluorane, 3-
Diethylamino-6-methyl-7-phenylaminofluorane, 3-di (n-butyl) amino-6-methyl-7
-Phenylaminofluorane, 3-di (n-pentyl)
Amino-6-methyl-7-phenylaminofluorane,
3-Diethylamino-7- (2-carbomethoxy-phenylamino) fluorane, 3- (N-ethyl-N-isoamylamino) -6-methyl-7-phenylaminofluorane, 3- (N-cyclohexyl-N- Methylamino) -6-methyl-7-phenylaminofluorane, 3
-Pyrrolidino-6-methyl-7-phenylaminofluorane, 3-piperidino-6-methyl-7-phenylaminofluorane, 3-diethylamino-6-methyl-7-
Xylidinofluorane, 3-diethylamino-7- (o
-Chlorophenylamino) fluorane, 3-dibutylamino-7- (o-chlorophenylamino) fluorane,
3-pyrrolidino-6-methyl-7-p-butylphenylaminofluorane, 3- (N-methyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluorane, 3- (N-ethyl Fluorane dyes such as -N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluorane.

Various compounds are known as colorants used in combination with a basic dye, and the following are exemplified. Inorganic acid substances such as activated clay, acid clay, attapulgite, bentonite, aluminum silicate, 4-hydroxydiphenoxide, α-naphthol, β-naphthol, 4-hydroxyacetophenone, 4-tert-butylphenol, hydroquinone, 4-tert-octyl Catechol, 4,4'-isopropylidene diphenol (bisphenol A), 4,4'-cyclohexylidene diphenol, 2,2'-dihydroxydiphenol, 2,
2'-methylenebis (4-methyl-6-tert-butylphenol), 4,4'-isopropylidenebis (2-te
rt-butylphenol), 4,4'-sec-butylidene diphenol, 4-phenylphenol, 2,2'-methylenebis (4-chlorophenol), 4,4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenyl Sulfone, 4-hydroxy-4'-methyldiphenyl sulfone, 4-hydroxy-4'-chlorodiphenyl sulfone, 4-hydroxy-4'-methoxydiphenyl sulfone, 4-hydroxy-4'-isopropoxydiphenyl sulfone, 4-hydroxy Benzyl benzoate, dimethyl 4-hydroxyphthalate, hydroquinone monobenzyl ether, novolac type phenol resin, phenolic compounds such as phenol polymers, benzoic acid,
p-tert-butylbenzoic acid, trichlorobenzoic acid, terephthalic acid, 3-sec-butyl-4-hydroxybenzoic acid, 3-cyclohexyl-4-hydroxybenzoic acid,
3,5-Dimethyl-4-hydroxybenzoic acid, salicylic acid, 3-isopropylsalicylic acid, 3-tert-butylsalicylic acid, 3-benzylsalicylic acid, 3- (α-methylbenzyl) salicylic acid, 3-chloro-5- (α- Aromatic carboxylic acids such as methylbenzyl) salicylic acid, 3,5-di-tert-butylsalicylic acid, 3-phenyl-5- (α, α-dimethylbenzyl) salicylic acid, 3,5-di-α-methylbenzylsalicylic acid, And these phenolic compounds, aromatic carboxylic acids and for example zinc, magnesium, aluminum, calcium, titanium, manganese,
Organic acid substances such as polyvalent metal salts such as tin and nickel.

In the present invention, the use ratio of the colorless or light-colored basic dye and the color developing agent in the heat-sensitive recording layer should be appropriately selected according to the types of the basic dye and the color developing agent to be used and is not particularly limited. However, in general, 1 to 7 parts by weight, preferably 1 to 4 parts by weight, of a coloring agent is used per 1 part by weight of the basic dye. The preparation of a coating liquid containing these substances is generally carried out by using water as a dispersion medium, stirring with a ball mill, an attritor, a horizontal sand mill or the like, and dispersing a color former and a color former together or separately by a pulverizer. The coating liquid is prepared to have an average particle size of 1 μm or less, preferably 0.5 μm or less.

In such a coating liquid, starch, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, polyvinyl alcohol, diisobutylene / maleic anhydride copolymer salt, styrene / maleic anhydride are usually used as binders. Copolymer salt, ethylene / acrylic acid copolymer salt,
Styrene / acrylic acid copolymer salt, natural rubber emulsion, styrene / butadiene copolymer emulsion, acrylonitrile / butadiene copolymer emulsion, methyl methacrylate / butadiene copolymer emulsion, polychloroprene emulsion, vinyl acetate emulsion, ethylene At least one kind such as vinyl acetate emulsion is added in an amount of 10 to 40% by weight, preferably 15 to 35% by weight, based on the total solid content of the recording layer.

If necessary, various auxiliary agents can be added to the coating solution, for example, disodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium lauryl alcohol sulfate, dispersant of fatty acid metal salt, stearin. Waxes such as zincate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax, ester wax, defoaming agent,
Fluorescent dyes, coloring dyes, etc. are appropriately added.

Various pigments may be used in combination in the coating liquid as long as the characteristics of the present invention are not impaired. For example, kaolin, clay, calcium carbonate, calcined clay, calcined kaolin, diatomaceous earth and fine anhydrous silica particles. , Inorganic pigments such as activated clay, styrene microballs, nylon powder,
Examples of the organic pigment include polyethylene powder, urea / formalin resin filler, and raw starch particles.

Further, a sensitizer may be used in combination depending on the purpose. Specific examples of the sensitizer include, for example, stearic acid amide, methoxycarbonyl-N-stearic acid benzamide, N-benzoylstearic acid amide, N-eicosanoic acid amide, ethylenebistearic acid amide, behenic acid amide, and methylenebisstearic acid. Amide, N-
Methylol stearamide, dibenzyl terephthalate, dimethyl terephthalate, dioctyl terephthalate,
Benzyl p-benzyloxybenzoate, phenyl 1-hydroxy-2-naphthoate, 2-naphthylbenzyl ether, m-terphenyl, dibenzyl oxalate, oxalate-di-p-methylbenzyl, oxalate-di-p- Chlorobenzyl, p-benzylbiphenyl, tolylbiphenyl ether, 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-diphenoxyethane, 1- (4-methoxyphenoxy) -2- (2-methylphenoxy) ethane, p-methylthiophenylbenzyl ether, 1,4-di (phenylthio) butane, p
-Acetotoluidide, p-acetophenetidide, N-acetoacetyl-p-toluidine, di (β-biphenylethoxy) benzene, p-di (vinyloxyethoxy) benzene, 1-isopropylphenyl-2-phenylethane and the like are exemplified. To be done. The amount of these sensitizers used is not particularly limited, but it is generally desirable to adjust the amount within the range of 4 parts by weight or less relative to 1 part by weight of the color developing agent.

In the present invention, a storability improver may be used in combination so as to further enhance the storability of a recorded image according to the purpose unless the effect is impaired. Specific examples of such storage improvers include 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-ethylenebis (4-methyl-6-tert-butylphenol) 2.
2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (4,6-di-te)
rt-butylphenol), 2,2'-ethylidenebis (4,6-di-tert-butylphenol), 2,2'-
Ethylidene bis (4-methyl-6-tert-butylphenol), 2,2'-ethylidene bis (4-ethyl-6-)
tert-butylphenol), 2,2 '-(2,2-propylidene) bis (4,6-di-tert-butylphenol), 2,2'-methylenebis (4-methoxy-6-te)
rt-butylphenol), 2,2'-methylenebis (6
-Tert-butylphenol), 4,4'-thiobis (3
-Methyl-6-tert-butylphenol), 4,4'-
Thiobis (2-methyl-6-tert-butylphenol), 4,4'-thiobis (5-methyl-6-tert-butylphenol), 4,4'-thiobis (2-chloro-)
6-tert-butylphenol), 4,4'-thiobis (2-methoxy-6-tert-butylphenol), 4,
4'-thiobis (2-ethyl-6-tert-butylphenol), 4,4'-butylidenebis (6-tert-butyl-m-cresol), 1- [α-methyl-α- (4'-
Hydroxyphenyl) ethyl] -4- [α ', α'-bis (4 "-hydroxyphenyl) ethyl] 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'-thiobis (3-methylphenol), 4,4'-dihydroxy -3, 3 ', 5,
5'-tetrabromodiphenyl sulfone, 4,4'-dihydroxy-3,3 ', 5,5'-tetramethyldiphenyl sulfone, 2,2-bis (4-hydroxy-3,5
-Dibromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,
Hindered phenol compounds such as 2-bis (4-hydroxy-3,5-dimethylphenyl) propane, N,
N'-di-2-naphthyl-p-phenylenediamine,
2,2'-methylenebis (4,6-di-tert-butylphenyl) sodium phosphate and the like can be mentioned.

In the present invention, the method for forming the heat-sensitive recording layer is not particularly limited, and suitable examples include air knife coating, varibar blade coating, pure blade coating, rod blade coating, short dwell coating, curtain coating and die coating. The coating liquid for the heat-sensitive recording layer is formed on the transparent support by various coating methods and dried. The coating amount of the recording layer coating liquid is 0.1 to 12 in dry weight.
g / m ^2, it is preferably adjusted in the range of about 0.3 to 10 / m ^2.

As the support, paper, synthetic paper, non-woven fabric, transparent paper, transparent plastic film or the like is used.

The heat-sensitive recording material of the present invention is provided with a protective layer on the heat-sensitive recording layer in order to make the storability of recorded images against chemicals and the like and the hue of the background clearer. The protective layer is composed mainly of a binder made of a water-soluble or water-dispersible polymer compound. Specific examples of such a binder 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, diisobutylene / maleic anhydride copolymer salt, styrene / maleic anhydride copolymer salt, ethylene. Acrylic acid copolymer salts, styrene / acrylic acid copolymer salts, styrene / butadiene copolymer emulsions, urea resins, melamine resins, amide resins, polyurethane resins and the like can be exemplified, and among them, acetoacetyl group-modified polyvinyl alcohol and carboxy. Modified polyvinyl alcohol is particularly preferably used because it can form a strong film.

The protective layer has a haze value of 2 or less and a thickness of 50 μm.
It is preferable that the protective layer coating liquid has a haze value of 35 or less when a protective layer of 3 g / m ^{2 is} provided on the PET film of m. In particular, when the haze value of the protective layer is lower than the haze value of the heat-sensitive recording layer, the golden color of the background part can be seen more clearly.

A pigment may be added to the protective layer as needed in order to further improve printability and sticking. Specific examples thereof include calcium carbonate,
Inorganic pigments such as zinc oxide, aluminum oxide, titanium dioxide, silicon dioxide, aluminum hydroxide, barium sulfate, zinc sulfate, talc, kaolin, clay, calcined kaolin, colloidal silica, styrene microballs, nylon powder, polyethylene powder, urea Examples include formalin resin fillers and organic pigments such as raw starch particles. It is generally desirable to adjust the amount used in the range of about 5 to 100 parts by weight with respect to 100 parts by weight of the binder component.

Further, in the protective layer coating liquid, if necessary, a lubricant such as zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax and ester wax, and a surfactant (dispersion such as sodium dioctylsulfosuccinate) 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 coating liquid for forming the protective layer is
Generally, water is used as the dispersion medium.

The coating solution for the protective layer thus prepared is coated on the thermosensitive recording layer by a suitable coating device, but if the coating amount exceeds 20 g / m ² in dry weight, the recording sensitivity may be significantly lowered. Therefore, in general, 0.1 to 20 g / m ² ,
It is desirable that the amount is adjusted within the range of 0.3 to 10 g / m ² .

The heat-sensitive recording material of the present invention may be provided with two or more heat-sensitive recording layers which develop different color tones. Further, various well-known techniques in the field of heat-sensitive recording material production, such as smoothing treatment such as super calendering after each layer coating, or pressure-sensitive adhesive treatment on the back surface of the recording material to process it into an adhesive label, are necessary. It can be added.

[0026]

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. Unless otherwise specified, "parts" and "%" in the examples mean "parts by weight" and "% by weight", respectively.

Example 1 Preparation of Liquid A 10 parts of 3-di (n-butyl) amino-6-methyl-7-phenylaminofluorane, 20 parts of 1,2-di (3-methylphenoxy) ethane, methylcellulose A composition comprising 30 parts of a 5% aqueous solution of 60 parts of water and 60 parts of water was pulverized with a sand mill until the average particle size became 0.8 μm.

Preparation of Solution B 20 parts of 4-hydroxy-4′-isopropoxydiphenylsulfone, 20 parts of 5% aqueous solution of methylcellulose,
A composition comprising 40 parts of water and water was pulverized with a sand mill until the average particle size became 0.8 μm.

Preparation of Coating Solution for Thermal Recording Layer Liquid A 120 parts, liquid B 80 parts, solid content 30% colloidal silica (average particle diameter 20 nm) 70 parts, solid concentration 50
% Styrene-butadiene 58 parts, 1 part of a 10% aqueous solution of sodium dioctylsulfosuccinate, and 70 parts of water were mixed and stirred to obtain a coating liquid for heat-sensitive recording layer. The resulting heat-sensitive recording layer coating liquid had a haze value of 1 and a thickness of 50 μm.
m PET film has a coating amount of 3 g / m ² after natural drying.
The haze value when applied was 24.

Preparation of Coating Liquid for Protective Layer Acetoacetyl group-modified polyvinyl alcohol [trade name:
Gocefimer Z-200, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.]
100 parts of 0% aqueous solution, 10 parts of 30% aqueous dispersion of colloidal silica, 3 parts of 30% emulsion of silicone oil,
A coating liquid for protective layer obtained by mixing and stirring a composition consisting of and 30 parts of water was obtained. The haze value of the obtained coating liquid for protective layer was 1
The haze value was 12 when the PET film having a thickness of 50 μm was applied at a coating amount of 3 g / m ² after natural drying.

Preparation of offset ink containing fine powder of Cu—Zn alloy Fine powder of Cu—Zn alloy having a zinc content of 30% (particle size 2
˜25 μm, thickness 0.2 μm) 15 parts, offset ink medium 100 parts by mixing and dispersing the composition C
An offset ink containing fine powder of u-Zn alloy was obtained.

Formation of Cu-Zn Alloy Fine-Powder-Containing Layer, Thermal Recording Layer, and Protective Layer ^On a synthetic paper of 80 g / m ² , the Cu-Zn alloy fine-powder-containing offset ink had a weight of 1 g / m 2. Print evenly over the entire surface so that it becomes ^2, and then apply the coating liquid for the heat-sensitive recording layer and the coating liquid for the protective layer at a coating amount of 3 g / m ² each after drying, and then dry. A thermal recording material was obtained by processing.

Example 2 In preparation of solution A, 3,3-bis (p-dimethylaminophenyl) -6 was used instead of 3-di (n-butyl) amino-6-methyl-7-phenylaminofluorane. A thermosensitive recording medium was obtained in the same manner as in Example 1 except that dimethylaminophthalide was used.

Example 3 Preparation of Coating Liquid for Protective Layer Acetoacetyl group-modified polyvinyl alcohol [trade name:
Gocefimer Z-200, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.]
100 parts of 0% aqueous solution, 10 parts of 30% zinc stearate aqueous dispersion, 3 parts of 30% emulsion of silicone oil,
A coating liquid for protective layer obtained by mixing and stirring a composition consisting of and 30 parts of water was obtained. The haze value of the obtained coating liquid for protective layer was 1
The haze value was 29 when the PET film having a thickness of 50 μm was coated at a coating amount of 3 g / m ² after natural drying.
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the above-mentioned protective layer coating liquid was used in place of the protective layer coating liquid used in Example 1.

[Comparative Example 1] In Example 1, Cu-Z
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the layer containing the fine powder of the n alloy was not provided.

Comparative Example 2 Preparation of Coating Solution for Thermal Recording Layer 120 parts of solution A, 80 parts of solution B, light calcium carbonate 21
Parts, 58 parts of styrene / butadiene having a solid concentration of 50%, 1 part of a 10% aqueous solution of sodium dioctylsulfosuccinate, and 100 parts of water were mixed and stirred to obtain a coating liquid for a heat-sensitive recording layer. The resulting heat-sensitive recording layer coating solution had a haze value of 1, and a PET film having a thickness of 50 μm and having a coating amount after natural drying of 3 g / m ² was 78, and the haze value was 78. A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the above-mentioned coating liquid for thermosensitive recording layer was used instead of the coating liquid for thermosensitive recording layer used in Example 1.

The density of the recorded image obtained by recording the thus obtained five kinds of thermal recording papers with NTTFAX-20R was measured by a Macbeth densitometer [Model 914 manufactured by Macbeth Co.] and the density of the background portion. The results of visually judging the sharpness of the golden color are shown in [Table 1].

[Golden clearness of background part] ◎: Very good ○: Excellent ×: Inferior

[0039]

[Table 1]

[0040]

As is clear from the results of [Table 1], the thermosensitive recording medium of the present invention was a golden thermosensitive recording medium having a clear background hue.

Claims (1)

[Claims] 1. A heat-sensitive recording material comprising a support, on which a colorless or light-colored basic dye and a coloring agent are contained, and a protective layer are provided in that order. The heat-sensitive recording layer has a haze value of 2.
Hereinafter, it was formed with a coating liquid for a heat-sensitive recording layer having a haze value of 40 or less when a heat-sensitive recording layer was provided on a PET film having a thickness of 50 μm at 3 g / m ² and further between the support and the heat-sensitive recording layer. A thermosensitive recording medium comprising a layer containing a fine powder of a Cu-Zn alloy.