JPH08230323A - Thermal recording material - Google Patents

Abstract

PURPOSE: To provide a thermal recording material excellent in recording running properties, recording density and gloss. CONSTITUTION: In a thermal recording material wherein a recording layer containing a leuco dye and a coupler and a protective layer containing an aq. resin are successively provided on a support, the aq. resin consists of polyvinyl alcohol and a polyurethane resin and epoxy modified silicone oil is added to a protective 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 utilizing a color reaction of a leuco dye and a color-developing agent, and more particularly to a heat-sensitive recording material having excellent recording running property, high recording density and excellent gloss. is there.

[0002]

2. Description of the Related Art A thermosensitive recording medium is known in which a color image is obtained by contacting both color-forming substances by heat by utilizing a color-forming reaction between a colorless or light-colored leuco dye and a color-developing agent.
Since such a thermosensitive recording medium is relatively inexpensive and 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. However, there are drawbacks in that fingerprint resistance and solvent resistance are poor, and, for example, when human sebum or a solvent comes into contact with the recording layer, the recording density is reduced, and unnecessary color development called background fog occurs.

As a method of solving such a drawback, a method of forming a protective layer containing an aqueous resin emulsion as a resin having film forming ability and chemical resistance on the heat sensitive recording layer (Japanese Patent Laid-Open No. 54-128347). Gazette) and a method of providing a protective layer containing a water-soluble polymer compound such as polyvinyl alcohol (Japanese Utility Model Publication No. 56-125354). However, in the method proposed so far,
With the improvement, new defects are accompanied, and satisfactory results are not always obtained.

For example, when an aqueous resin coating is applied on the heat-sensitive recording layer, it is necessary to limit the drying temperature in order to avoid color development of the recording layer due to high temperature drying, and inevitably the curing of the resin layer becomes insufficient. During recording, a phenomenon occurs such that the recording head and the resin layer adhere to each other. Therefore, it has been attempted to improve recording runnability by adding a pigment, a lubricant, a curing agent and the like.

On the other hand, in recent years, various printers such as video printers which provide high quality images of photographic tone have come to be used, and thermal recording materials for printout have better recording density and gradation. Is required. Therefore, development of a thermosensitive recording medium excellent in gradation expression using a plastic film, synthetic paper, or highly smooth coated paper as a support is under way. In order to improve the storability of recorded images and the recording runnability in such a thermosensitive recording medium, a protective layer containing polyvinyl alcohol and a polyurethane resin is disclosed in JP-A-3-67688 and modified silicone oil. Contained protective layer
As described in Japanese Patent No. 542, however, when recording with a video printer, especially under high humidity conditions, the overcoat layer adheres to the recording head and the paper feed guide, which often causes a paper jam problem. Further, when a pigment is added to the overcoat layer in order to improve recording runnability, a high transparency and high gloss surface cannot be obtained, and the recording density itself is not always satisfactory.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermosensitive recording medium in which the above-mentioned drawbacks are eliminated and which has extremely excellent recording runnability and which has a high recording density and excellent gloss. .

[0007]

SUMMARY OF THE INVENTION The present invention comprises:
A thermosensitive recording medium comprising a recording layer containing a leuco dye and a colorant, and a protective layer containing an aqueous resin, wherein the aqueous resin is polyvinyl alcohol and a polyurethane resin, and the protective layer contains an epoxy-modified silicone oil. By including the above, the above problems have been solved and completed.

[0008]

The present invention is characterized in that the protective layer contains polyvinyl alcohol, a polyurethane resin and an epoxy-modified silicone oil. The amount of polyvinyl alcohol, the polyurethane resin and the epoxy-modified silicone oil used is not particularly limited, but the total amount of the protective layer is not limited. The polyvinyl alcohol and the polyurethane resin are adjusted to 20 to 70% by weight, preferably 30 to 50% by weight, and the epoxy-modified silicone oil is adjusted to 1 to 30% by weight, preferably 5 to 20% by weight, based on the solid amount. Is desirable.

Specific examples of polyvinyl alcohol used for the protective layer include the following substances. Fully saponified or partially saponified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol having an acetoacetyl group introduced by reacting polyvinyl alcohol with diketene, vinyl acetate and maleic acid, fumaric acid, itaconic acid, crotonic acid, acrylic acid, Carboxy-modified polyvinyl alcohol obtained as a saponification product of a copolymer with an ethylenically unsaturated carboxylic acid such as methacrylic acid, a copolymer of vinyl acetate and an olefin sulfonic acid such as ethylene sulfonic acid, allyl sulfonic acid, or a salt thereof. Sulfonic acid-modified polyvinyl alcohol obtained as a saponified product, an olefin-modified polyvinyl obtained by saponifying a copolymer of vinyl acetate and an olefinic acid such as ethylene, propylene, isobutylene, α-dotecene, α-octadotecene. Nitrile alcohol, vinyl acetate and nitrile-modified polyvinyl alcohol obtained as a saponification product of copolymers of nitriles such as acrylonitrile and methacrylonitrile, and saponification of copolymers of vinyl acetate and amides such as acrylamide and methacrylamide. Of the amide-modified polyvinyl alcohol and the pyrrolidone-modified polyvinyl alcohol and vinyl ester obtained by saponifying the copolymer of vinyl acetate and N-vinylpyrrolidone, and an olefinically unsaturated monomer containing a silyl group in the molecule. Silicone-modified polyvinyl alcohol obtained by saponifying the copolymer. Of these, acetoacetyl group-modified polyvinyl alcohol is particularly preferable because it has excellent compatibility with the polyurethane resin and the epoxy-modified silicone oil and also has excellent water resistance.

Polyurethane resins used in the present invention include, for example, polyester type polyurethane resins, polyester type polyurethane resins, aliphatic type polyurethane resins and the like. Among them, aliphatic type polyurethane resins are preferable because of excellent recording running property. The polyurethane resin is used in a water-soluble or emulsion system, and in the emulsion system, a so-called soap-free emulsion without a surfactant is possible due to the hydrophilicity of the functional group. When synthesizing a polyurethane resin, or when selecting from commercial products, things to be careful of are the adhesive strength with other layers, film-forming property,
Matching property with a thermal head is mentioned. It is preferable that the polyurethane resin be purified as much as possible, because the occurrence of background fog is small. Especially in the case of an emulsion system, the type and amount of the surfactant must be carefully selected, and soap-free is most preferable.

Further, the softening point of the resin used for the protective layer has a great influence on the recording runnability of the thermosensitive recording medium. Even with the above polyurethane resin, the softening point of the coating is 80 ° C.
If it is less than the above range, the coating of the polyurethane resin may be melted by the heat of the thermal head during recording and sticking may occur, resulting in a marked decrease in recording runnability. Preferably, by using a polyurethane resin film having a softening point of 80 ° C. or higher, recording runnability is further improved.

The proportion of polyvinyl alcohol and polyurethane resin used is not particularly limited, but is 20 to 100 parts by weight of polyvinyl alcohol.
It is desirable to use 500 parts by weight, especially 50 to 300 parts by weight of polyurethane resin.

The epoxy-modified silicone oil used in the protective layer is dimethylpolysiloxane, hydrogenpolysiloxane, or the like having an epoxy group introduced into the side chain or terminal. These hydrophobic silicone oils can be emulsified or introduced with a hydrophilic group such as a polyether group other than the epoxy group to be water-soluble and used.

Further, a pigment may be added to the protective layer within a range not impairing the effects of the present invention. Specific examples thereof include calcium carbonate, zinc oxide, aluminum oxide, titanium dioxide, silicon dioxide and water. Aluminum oxide,
Barium sulfate, zinc sulfate, talc, kaolin, clay,
Inorganic pigments such as calcined kaolin, calcined clay, colloidal silica, styrene microballs, nylon powder, polyethylene powder, urea / formalin resin filler,
Examples include organic pigments such as raw starch particles. However, since addition of a large amount of these pigments lowers transparency and gloss, the amount used is preferably 50% by weight or less of the total solid content in the protective layer.

Further, in the coating liquid for forming the protective layer, zinc stearate, calcium stearate,
Lubricants such as polyethylene wax, carnauba wax, paraffin wax and ester wax, surfactants such as sodium dioctyl sulfosuccinate, and various auxiliaries such as defoaming agents can be appropriately added. Further, a curing agent such as glyoxal, boric acid, dialdehyde starch, or an epoxy compound can be added to further improve water resistance.

As the colorless or light-colored basic dye used in the present invention, various known dyes can be used, and specific examples thereof include the following.
3- (4-diethylamino-2-ethoxyphenyl)-
3- (1-ethyl-2-methylindol-3-yl)
-4-azaphthalide, crystal violet lactone, 3- (N-ethyl-N-isopentyl) amino-6
-Methyl-7-anilinofluorane, 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluorane 3-diethylamino-6-methyl-7-anilinofluorane, 3- Diethylamino-6-methyl-7
-(O, p-dimethylanilino) fluorane, 3- (N
-Ethyl-Np-toluidino) -6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-
Anilinofluorane, 3-di (n-butyl) amino-6
-Methyl-7-anilinofluorane, 3- (N-cyclohexyl-N-methyl) amino-6-methyl-7-anilinofluorane, 3-diethylamino-7- (o-chloroanilino) fluorane, 3-dibutyl Amino-7-
(O-chloroanilino) fluorane, 3-diethylamino-7- (m-trifluoromethylanilino) fluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6-methylfluorane,
3-cyclohexylamino-6-chlorofluorane, 3
-(N-ethyl-N-hexyl) amino-6-methyl-
7- (p-chloroanilino) fluorane and the like. Of course, two or more kinds of such basic dyes can be used in combination.

Various compounds are known as colorants used in combination with leuco dyes, such as 4-cumylphenol, hydroquinone monobenzyl ether, 4, and the like.
4'-isopropylidenediphenol, 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4 '
-Dihydroxydiphenyl-2,2-butane, 4,4 '
-Dihydroxydiphenyl sulfide, bis (4-hydroxy-3-methylphenyl) sulfide, 4,4'-
Dihydroxydiphenyl sulfone, 2,4'-dihydroxydiphenyl sulfone, 4-hydroxy-4'-methyldiphenyl sulfone, 4-hydroxy-4'-isopropoxydiphenyl sulfone, bis (3-allyl-4-
Hydroxyphenyl) sulfone, 4-hydroxyphenyl-4'-benzyloxyphenyl sulfone, 4-hydroxy-3 ', 4'-tetramethylene biphenyl sulfone, 3,4-dihydroxyphenyl-p-tolyl sulfone, 4-hydroxybenzoic acid. Benzyl ester, N,
N'-di-m-chlorophenylthiourea, 4,4'-bis (p-tolylsulfonylaminocarbonylamino) diphenylmethane, 4- [2- (p-methoxyphenoxy) ethyloxy] salicylic acid, 4- {3- (p -Tolylsulfonyl) propyloxy] zinc salicylate, 5-
[P- (2-p-methoxyphenoxyethoxy) cumyl] zinc salicylate and the like can be mentioned. In addition, if necessary, two or more kinds of these color-developing agents can be used in combination.

In the present invention, the use ratio of the leuco dye and the coloring agent in the recording layer is appropriately selected according to the types of the leuco dye and the coloring agent used, and is not particularly limited, but generally 1 to 10 parts by weight, preferably 1 to 5 parts by weight, of an acidic substance is used with respect to 1 part by weight of a colorless or light-colored leuco dye.

In the preparation of a coating liquid containing these substances, water is generally used as a dispersion medium, and the leuco dye and the color developing agent are mixed together or separately by stirring with a ball mill, attritor, sand mill or the like and a pulverizer. An average particle diameter of 2 μm or less, preferably 1 μm or less is dispersed to prepare a coating liquid.

In such a coating liquid, starch, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, polyvinyl alcohol, alkali salt of styrene / maleic anhydride copolymer, ethylene / acrylic acid are usually used as binders. Alkali salt of copolymer, alkali salt of styrene / acrylic acid copolymer, natural rubber emulsion, styrene / butadiene copolymer emulsion, acrylonitrile / butadiene copolymer emulsion, methyl methacrylate / butadiene copolymer emulsion, polychloroprene Emulsion, vinyl acetate emulsion, ethylene / vinyl acetate emulsion and the like are added in an amount of about 5 to 20% by weight of the total solid content of the recording layer.

If desired, various additives are used in combination, for example, lubricants such as zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax, ester wax; calcium carbonate, zinc oxide, aluminum oxide, titanium dioxide. , Silicon dioxide, aluminum hydroxide, barium sulfate, talc,
Inorganic pigments such as kaolin, clay, calcined clay and colloidal silica; organic pigments such as styrene microballs, nylon powder, polyethylene powder, urea / formalin resin fillers; stearic acid amide, N-methylstearic acid amide, benzalinide, methylene stearate. Fatty acid amides such as bisamide;

4,4'-butylidene bis (6-tert-butyl-3-methylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,
4-di-tert-butyl-3-methylphenol, 1,
1,3-tris (2-methyl-4-hydroxy-5-te
rt-Butylphenyl) butane, 1,1,3-tris (5
-Cyclohexyl-4-hydroxy-2-methylphenyl) butane, 1,3,5-tris (5-tert-butyl-
Hindered phenols such as 3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid; 4- (2-methyl-1,2-epoxyethyl) diphenylsulfone, 4
Diphenylsulfone derivatives such as-(2-ethyl-1,2-epoxyethyl) diphenylsulfone and 4-benzyloxy-4 '-(2,3-glycidyloxy) diphenylsulfone; 2- (2'-hydroxy-5' -Methylphenyl) benzotriazole, 2-hydroxy-
UV absorbers such as 4-benzyloxybenzophenone;
1,2-di (3-methylphenoxy) ethane, 1,2-
Diphenoxyethane, parabenzyl biphenyl, naphthylbenzyl ether, benzyl-4-methylthiophenyl ether, 1-hydroxy-2-naphthoic acid phenyl ester, oxalic acid dibenzyl ester, oxalic acid-di-p-methylbenzyl ester, oxalic acid Examples thereof include heat sensitivity improvers (sensitizers) such as di-p-chlorobenzyl ester, terephthalic acid dibutyl ester, terephthalic acid dibenzyl ester, and isophthalic acid dibutyl ester.

The average particle diameter of the above additives contained in the heat-sensitive recording layer is preferably 2 μm or less. The amount of the additive used is not particularly limited, but for example, the amount of the sensitizer used is generally 4 with respect to 1 part by weight of the color developing agent.
It is desirable to adjust within the range of not more than parts by weight.

The method for forming the recording layer and the protective 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. It is formed by a method such as coating and drying the coating liquid for the recording layer on the support by various coating methods. As the support, paper, synthetic paper, film, or the like is used, and when a transparent film is used, excellent transparency and recording runnability can be obtained.

The coating amount of the coating liquid for the recording layer is adjusted to a dry weight of 1 to 20 g / m ² , preferably 5 to 15 g / m ² . The coating amount of the coating liquid for the protective layer is adjusted in the range of 0.5 to 5 g / m ^{2 in} dry weight.

If desired, a resin layer may be provided on the protective layer and / or on the back surface of the heat-sensitive recording sheet to further improve the storability of the heat-sensitive recorded image. In addition, various known techniques in the field of producing a thermal recording medium can be applied by subjecting the back surface to an adhesive label to process it into an adhesive label or providing a magnetic layer. Of course, it is also possible to improve the image quality and the image density by applying a super calender treatment after forming the undercoat layer, the heat-sensitive recording layer and the protective layer.

[0027]

EXAMPLES The thermal recording material of 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, "part" and "%" in an example show "weight part" and "weight%", respectively, unless there is particular notice.

Example 1 Preparation of Solution A A composition comprising 10 parts of 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluorane, 5 parts of a 5% aqueous solution of methylcellulose, and 40 parts of water. Was pulverized with a sand mill until the average particle size became 1 μm.

Preparation of Solution B 30 parts of 4-hydroxy-4′-isopropyloxydiphenyl sulfone, 5 parts of 5% aqueous solution of methylcellulose,
A composition consisting of 80 parts of water was sand milled to have an average particle size of 1
It was pulverized to a size of μm.

Preparation of Solution C A composition consisting of 20 parts of 1,2-di (3-methylphenoxy) ethane, 5 parts of a 5% aqueous solution of methylcellulose, and 55 parts of water was pulverized with a sand mill until the average particle diameter became 1 μm.

Formation of Recording Layer Liquid A 55 was formed on a transparent polyester film having a thickness of 75 μm.
Part, 115 parts of B solution, 80 parts of C solution, and 80 parts of 10% polyvinyl alcohol aqueous solution are mixed and stirred to obtain a coating solution having a coating amount after drying of 6 g / m ² and then heat-sensitive. I got a record.

Preparation of liquid D: Acetoacetyl group-modified polyvinyl alcohol (trade name:
Gocefimer Z-200, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
200% of 10% aqueous solution of, polyurethane resin (trade name:
Teisan Urethane SL-2108, manufactured by Teikoku Chemical Industry Co., Ltd.)
50 parts of epoxy modified silicone oil emulsion (trade name: Polon MF-11B, manufactured by Shin-Etsu Chemical Co., Ltd.) and 100 parts of water were mixed and stirred to obtain a coating liquid for forming a protective layer.

Formation of Protective Layer Liquid D is applied and dried on the recording layer so that the coating amount after drying is 3 g / m ² , a protective layer is provided, and a super calendering treatment is further performed to obtain a thermosensitive recording medium. Got

Example 2 In the preparation of liquid D of Example 1, polyurethane resin (trade name: Teisan Urethane SL-2108, manufactured by Teikoku Chemical Industry Co., Ltd.) was used (trade name: Teisan Urethane SL-2101, manufactured by Teikoku Chemical Industry Co., Ltd.). A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the above was changed.

Example 3 In the preparation of solution D of Example 1, 10% of an aqueous solution of polyvinyl alcohol modified with acetoacetyl group (trade name: Gocefimer Z-200, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was used.
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the aqueous solution of acetoacetyl group-modified polyvinyl alcohol (trade name: Gocefimer Z-210, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was used.

Example 4 In the preparation of solution D of Example 1, an epoxy-modified silicone oil emulsion (trade name: Polon MF-11 was used.
B, manufactured by Shin-Etsu Chemical Co., Ltd.) was changed to an amino-modified silicone oil emulsion (trade name: Polon MF-14D, manufactured by Shin-Etsu Chemical Co., Ltd.) to obtain a thermosensitive recording medium in the same manner as in Example 1.

Comparative Example 1 In the preparation of the D liquid of Example 1, 200 parts of a 10% aqueous solution of acetoacetylated polyvinyl alcohol (trade name: Gocefimer Z-200, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), polyurethane resin (trade name) : Teisan Urethane SL-21
08, Teikoku Chemical Industry Co., Ltd.) 50 parts to 10 parts aqueous solution of acetoacetylated polyvinyl alcohol (trade name: Gocefimer Z-200, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 250 parts A thermosensitive recording medium was obtained.

Comparative Example 2 In the preparation of the D liquid of Example 1, 200 parts of a 10% aqueous solution of acetoacetylated polyvinyl alcohol (trade name: Gocefimer Z-200, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), polyurethane resin (trade name) : Teisan Urethane SL-21
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that 50 parts of 08, manufactured by Teikoku Chemical Industry Co., Ltd. was changed to 250 parts of a polyurethane resin (trade name: Teisan Urethane SL-2108, manufactured by Teikoku Chemical Industry Co., Ltd.).

Comparative Example 3 In the preparation of the liquid D of Example 1, an epoxy-modified silicone oil emulsion (trade name: Polon MF-11 was used.
B, manufactured by Shin-Etsu Chemical Co., Ltd. was changed to an aqueous dispersion of zinc stearate (trade name: Hydrin Z-7, manufactured by Chukyo Yushi Co., Ltd.) to obtain a thermosensitive recording medium in the same manner as in Example 1.

Comparative Example 4 A polyurethane resin was used as a styrene / butadiene copolymer latex (trade name: L-15) in the preparation of the liquid D of Example 1.
No. 71, manufactured by Asahi Kasei Co., Ltd.) was carried out in the same manner as in Example 1 to obtain a thermosensitive recording medium.

The following evaluations were carried out on the respective samples of the thermal recording materials obtained in the examples and comparative examples, and the results obtained are shown in Table 1. (1) Runnability (sticking property) The runnability when recorded with a thermal printer (UP-930, manufactured by Sony Corporation) and the noise during recording were evaluated. (Evaluation criteria) ○: No problem in practical use. Δ: There is some problem in practical use. X: There is a problem in practical use.

(2) Recording Density The density of the obtained recorded image is measured by a Macbeth densitometer (RD-100
Type, manufactured by Macbeth). (3) Glossiness Based on the method described in JIS P 8142, it was measured at an incident angle of 75 ° with a goniophotometer.

(4) Transparency The haze value was measured with a haze meter (TC-HIII type, manufactured by Tokyo Denshoku Co., Ltd.).

[0044]

[Table 1]

[0045]

As is clear from the results of Table 1, the thermal recording material of the present invention was a thermal recording material excellent in recording runnability, gloss and recording density.

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[Procedure amendment]

[Submission date] April 4, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

On the other hand, in recent years, various printers such as video printers which provide high quality images of photographic tone have come to be used, and thermal recording materials for printout have better recording density and gradation. Is required. Therefore, development of a thermosensitive recording medium excellent in gradation expression using a plastic film, synthetic paper, or highly smooth coated paper as a support is under way. In order to improve the storability of recorded images and the recording runnability in such a thermosensitive recording medium, a protective layer containing polyvinyl alcohol and a polyurethane resin is disclosed in JP-A-3-67688 and modified silicone oil. The protective layer contained is disclosed in
As described in Japanese Patent No. 8542, particularly when recording with a video printer under a high humidity condition, the protective layer adheres to the recording head and the paper feed guide, which often causes a paper jam problem. Further, when a pigment is added to the protective layer in order to improve recording runnability, a highly transparent or highly glossy surface cannot be obtained, and the recording density itself is not always satisfactory.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

The present invention is characterized in that the protective layer contains polyvinyl alcohol, a polyurethane resin and an epoxy-modified silicone oil. The amounts of polyvinyl alcohol, polyurethane resin and epoxy-modified silicone oil used are not particularly limited, but the total amount of the protective layer is not limited. The polyvinyl alcohol and the polyurethane resin are adjusted to 20 to 70% by weight, preferably 30 to 50% by weight, and the epoxy-modified silicone oil is adjusted to 1 to 30% by weight, preferably 5 to 20% by weight, based on the solid amount. Is desirable.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

Examples of the polyurethane resin used in the present invention include polyester-based polyurethane resin and polyester.
There are ether polyurethane resins, aliphatic polyurethane resins and the like. Among them, aliphatic polyurethane resins are preferable because of their excellent recording running properties. The polyurethane resin is used in a water-soluble or emulsion system, and in the emulsion system, a so-called soap-free emulsion without a surfactant is possible due to the hydrophilicity of the functional group. When synthesizing a polyurethane resin, or when selecting from commercial products, things to be careful of are the adhesive strength with other layers, film-forming property,
Matching property with a thermal head is mentioned. It is preferable that the polyurethane resin be purified as much as possible, because the occurrence of background fog is small. Especially in the case of an emulsion system, the type and amount of the surfactant must be carefully selected, and soap-free is most preferable.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

The proportion of polyvinyl alcohol and polyurethane resin used is not particularly limited, but it is 30 to 100 parts by weight of polyvinyl alcohol.
It is desirable to use 350 parts by weight, especially 50 to 200 parts by weight of polyurethane resin.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

The leuco dye used in the present invention includes:
Various known materials can be used, and specific examples thereof include the following. 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-
2-methylindol-3-yl) -4-azaphthalide, crystal violet lactone, 3- (N -ethyl)
L-N-isoamyl) amino-6-methyl-7-anili
Nofluorane, 3-diethylamino-6-methyl-7-
Anilinofluorane, 3-diethylamino-6-methyl-7- (o, p-dimethylanilino) fluorane, 3-
(N-ethyl-N-p-toluidino) -6-methyl-7
-Anilinofluorane, 3-pyrrolidino-6-methyl-
7-anilinofluorane, 3-di (n-butyl) amino-6-methyl-7-anilinofluorane, 3- (N-cyclohexyl-N-methyl) amino-6-methyl-7-
Anilinofluorane, 3-diethylamino-7- (o-
Chloroanilino) fluorane, 3-dibutylamino-7
-(O-chloroanilino) fluorane, 3-diethylamino-7- (m-trifluoromethylanilino) fluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6-methylfluorane, 3 -Cyclohexylamino-6-chlorofluorane, 3- (N-ethyl-N-hexyl) amino-6-methyl-7- (p-chloroanilino) fluorane and the like. Of course, it is also possible to use two or more of these leuco dyes in combination.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

Preparation of liquid D: Acetoacetyl group-modified polyvinyl alcohol (trade name:
Gocefimer Z-200, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
200% of 10% aqueous solution of, polyurethane resin (trade name:
Teisan Urethane SL-2108, solid concentration 40%, Teikoku Chemical Industry Co., Ltd. 50 parts, epoxy modified silicone oil emulsion (trade name: Polon MF-11B, solid)
20 parts of a shape concentration of 30%, manufactured by Shin-Etsu Chemical Co., Ltd.) and 100 parts of water were mixed and stirred to obtain a coating liquid for forming a protective layer.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

Example 2 In the preparation of the liquid D of Example 1, a polyurethane resin (trade name: Teisan Urethane SL-2108, solid concentration 40) was used.
% (Manufactured by Teikoku Chemical Industry Co., Ltd.) (trade name: Teisan Urethane SL-2101, solid concentration 40%, manufactured by Teikoku Chemical Industry Co., Ltd.)
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the above was changed.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

Example 4 In the preparation of solution D of Example 1, an epoxy-modified silicone oil emulsion (trade name: Polon MF-11 was used.
B, manufactured by Shin-Etsu Chemical Co., Ltd., is an amino-modified silicone oil emulsion (trade name: Polon MF-14D, solid).
Shape concentration 30%, manufactured by Shin-Etsu Chemical Co., Ltd.)
A thermal recording material was obtained in the same manner as in Example 1.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

Comparative Example 3 In the preparation of the liquid D of Example 1, an epoxy-modified silicone oil emulsion (trade name: Polon MF-11 was used.
B, manufactured by Shin-Etsu Chemical Co., Ltd., was changed to an aqueous dispersion of zinc stearate (trade name: Hydrin Z-7, solid concentration 30%, manufactured by Chukyo Yushi Co., Ltd.) in the same manner as in Example 1 for thermal recording. Got

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction content]

Comparative Example 4 A polyurethane resin was used as a styrene / butadiene copolymer latex (trade name: L-15) in the preparation of the liquid D of Example 1.
71, solid concentration 45%, manufactured by Asahi Kasei Co., Ltd.) to obtain a thermosensitive recording medium in the same manner as in Example 1.

Claims (3)

[Claims] 1. A thermosensitive recording medium comprising a support, on which a recording layer containing a leuco dye and a coloring agent and a protective layer containing an aqueous resin are sequentially provided, wherein the aqueous resin is polyvinyl alcohol and a polyurethane resin. A heat-sensitive recording material characterized by containing an epoxy-modified silicone oil in the protective layer. 2. The heat-sensitive recording material according to claim 1, wherein the polyvinyl alcohol is acetoacetyl group-modified polyvinyl alcohol. 3. The heat-sensitive recording material according to claim 1, wherein the polyurethane resin is an aliphatic polyurethane resin.