JPH0664327A - Thermal recording body - Google Patents

Abstract

PURPOSE:To obtain a thermal recording body superior in pixel reproducibility in every range from a low density to a high density, enhanced in recording density, superior in cutting suitability, and free from an adhesion of a head scum. CONSTITUTION:In a thermal recording body provided with a thermal recording layer on a substrate, an intermediate layer mainly composed of a pigment having an oil absorption not less than 80ml/100g and a graft coploymer of a polyvinyl alcohol and an (acrylic amide.acrylic acid.acrylonitrile) coploymer is provided between the substrate and the 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, and more particularly to a heat-sensitive recording material having excellent print pixel reproducibility, high recording density and excellent surface strength.

[0002]

2. Description of the Related Art Conventionally, a heat-sensitive recording which utilizes a color reaction between a color-forming agent and a color-forming agent which develops color by contacting with the color-forming agent, by contacting both color-forming substances with heat to obtain a color-developed image. The body is well known. Since such a thermal recording medium is relatively inexpensive and the recording device is compact and its maintenance is relatively easy, it is used not only as a recording medium for facsimiles and various computers but also in a wide range of fields.

With the diversification of uses, heat sensitivity is excellent in reproducibility of print pixels in any area from low density to high density, and a high quality recorded image comparable to silver halide photography can be obtained. The demand for recording media is increasing. Further, with the increase in speed of recording equipment, there is an increasing demand for a thermal recording material having excellent dynamic recording sensitivity.

In order to obtain such a high-sensitivity and high-quality heat-sensitive recording material, an intermediate layer composed of an oil-absorbing pigment may be provided (Japanese Patent Laid-Open Nos. 59-155097 and 61-44683).
Furthermore, a method of improving smoothness and heat insulation by combining these layers in multiple layers (JP-A-61-112886, JP-A-6-11286).
1-193880) and the like have been proposed. However, when an inorganic pigment having a high oil absorption property such as amorphous silica or calcined clay is used as the oil-absorption material, there is a drawback that the surface area becomes large and the paper surface strength decreases. Increasing the rate is accompanied by the drawback that the recording density is significantly reduced. Therefore, there is still room for improvement in order to obtain an overall balanced quality.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to provide a high-quality recorded image with excellent reproducibility of print pixels in any area from low density to high density without the drawbacks described above. The object is to provide a heat-sensitive recording material.

[0006]

The above-mentioned objects of the present invention are achieved by providing an intermediate layer having a specific composition between the support and the recording layer. Thus, the present invention provides a thermosensitive recording medium having a thermosensitive recording layer on a support, a pigment having an oil absorption of 80 ml / 100 g or more and polyvinyl alcohol (acrylamide) between the support and the recording layer. A heat-sensitive recording material comprising an intermediate layer containing a graft copolymer with an acrylic acid / acrylonitrile) copolymer as a main component.

[0007]

As described above, the heat-sensitive recording material of the present invention comprises a pigment having an oil absorption of 80 ml / 100 g or more, polyvinyl alcohol and a (acrylamide / acrylic acid / acrylonitrile) copolymer between the support and the recording layer. Although it has an important feature in that an intermediate layer containing a graft copolymer as a main component is provided, the above-mentioned specific graft copolymer has excellent adhesiveness to various inorganic pigments, and is particularly amorphous. It has been revealed that an intermediate layer having excellent surface strength is formed because it exhibits outstandingly excellent adhesiveness to pigments having an oil absorption of 80 ml / 100 g or more, such as silica, aluminum silicate and calcined clay. Even with the above-mentioned specific graft copolymer, if the blending amount is too large, the oil absorbency and heat retention of the intermediate layer are lowered, and the head meal and the recording density tend to be lowered. In order to obtain the desired effects of the present invention while maintaining a good quality balance, the amount of the pigment is adjusted in the range of 1 to 50 parts by weight, preferably 2 to 30 parts by weight, relative to 100 parts by weight of the pigment. Is desirable.

Further, in the intermediate layer, in addition to the oil-absorbing pigments as described above, various inorganic pigments such as talc and light calcium carbonate which are usually used, amino resins, phenol resins and styrene resins are also used. It is also possible to use an organic pigment together. Further, the specific graft copolymer, it is also possible to use an ordinary binder in combination, for example, starch, casein, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, water-soluble polymers such as polyacrylic acid Styrene / butadiene based copolymer, styrene / acrylic acid based copolymer, acrylonitrile / butadiene based copolymer,
You may use together various synthetic resin emulsions, such as colloidal silica particle composite styrene-acrylic acid ester copolymer, acrylic acid type copolymer, etc. The amount of the intermediate layer applied to the support is preferably adjusted so that the thickness is about 5 to 40 μm, and may be a multilayer structure having two or more layers.

The support is not particularly limited, and high-quality paper, base paper made by Yankee machine, single-sided gloss base paper,
Papers such as double-sided glossy base paper, cast coated paper, art paper, coated paper, medium coated paper, synthetic fiber paper, synthetic resin film and the like are appropriately used. The method for applying the intermediate layer is not particularly limited, and may be applied and dried by an appropriate application device such as an air knife coater, a blade coater, a bar coater, a gravure coater, a curtain coater, a short dwell coater.

The heat-sensitive recording layer is applied onto the intermediate layer thus formed and dried to produce the heat-sensitive recording material of the present invention. Regarding the combination of the color former and the color former contained in the recording layer. Is not particularly limited, and any combination can be used as long as they are brought into contact with each other by heat to cause a color reaction, for example, a colorless or pale basic dye and an inorganic or organic acidic substance. And a combination of a higher fatty acid metal salt such as ferric stearate and a phenol such as gallic acid. Further, it can be applied to various heat-sensitive recording materials such as a heat-sensitive recording material in which a diazonium compound, a coupler and a basic substance are combined, so that a recorded image can be obtained by heat.

However, since the specific intermediate layer of the present invention provided on the support exerts an excellent effect particularly in the combination of the basic dye and the acidic substance, it is particularly preferably applied to such a combination.

In the heat-sensitive recording material of the present invention, various types of basic dyes of a colorless or pale color, which form a recording layer together with a specific coloring agent and a heat-fusible substance, are known, and for example, the following are known. Is exemplified. 3,3-bis (p-
Dimethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) -3-
(1,2-dimethylindol-3-yl) phthalide,
3- (p-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide, 3 , 3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,3-bis (9-ethylcarbazol-3-yl) -6-dimethylaminophthalide, 3,3 -Bis (2
-Phenylindol-3-yl) -6-dimethylaminophthalide, 3-p-dimethylaminophenyl-3-
Triarylmethane dyes such as (1-methylpyrrol-3-yl) -6-dimethylaminophthalide, 4,4'-
Bis-dimethylaminobenzhydrylbenzyl ether, N-halophenyl-leuco auramine, N-2,
Diphenylmethane dyes such as 4,5-trichlorophenylleuco auramine, benzoyl leuco methylene blue, thiazine dyes such as p-nitrobenzoyl leuco methylene blue, 3-methyl-spiro-dinaphthopyran,
3-ethyl-spiro-dinaphthopyran, 3-phenyl-
Spiro dyes such as spiro-dinaphthopyran, 3-benzyl-spiro-dinaphthopyran, 3-methyl-naphtho (6'-methoxybenzo) spiropyran, 3-propyl-spiro-dibenzopyran, rhodamine-B-anilinolactam, rhodamine ( Lactam dyes such as p-nitroanilino) lactam and 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-methylaminofluorane, 3-diethylamino-7-N-methylaminofluorane, 3-diethylamino-7-di Benzylaminofluorane, 3-diethylamino-7-N-methyl-
N-benzylaminofluorane, 3-diethylamino-
7-N-chloroethyl-N-methylaminofluorane,
3-diethylamino-7-N-diethylaminofluorane, 3- (N-ethyl-p-toluidino) -6-methyl-7-phenylaminofluorane, 3- (N-ethyl-
p-toluidino) -6-methyl-7- (p-toluidino) fluorane, 3-dimethylamino-6-methyl-7
-Phenylaminofluorane, 3-diethylamino-6
-Methyl-7-phenylaminofluorane, 3-di-n
-Butylamino-6-methyl-7-phenylaminofluorane, 3-di-n-pentylamino-6-methyl-7
-Phenylaminofluorane, 3-diethylamino-7
-(2-carbomethoxy-phenylamino) fluorane, 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-di-n- Butylamino-7- (o-chlorophenylamino) fluorane,
3-pyrrolidino-6-methyl-7-p-butylphenylaminofluorane, 3- (N-methyl-Nn-amyl) amino-6-methyl-7-phenylaminofluorane, 3- (N-ethyl) -N-n-amyl) amino-6-
Methyl-7-phenylaminofluorane, 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-phenylaminofluorane, 3- (N-methyl-Nn-hexyl) amino-6- Methyl-7-phenylaminofluorane, 3- (N-ethyl-Nn-hexyl) amino-6-methyl-7-phenylaminofluorane, 3-
(N-ethyl-N-β-ethylhexyl) amino-6-
Methyl-7-phenylaminofluorane, 3- (N-ethyl-N-tetrahydrofurfuryl) amino-6-methyl-7-phenylaminofluorane, 3- (N-ethyl-N-cyclopentyl) amino-6- Methyl-7-phenylaminofluorane, 2,2-bis {4- [6'-
(N-Cyclohexyl-N-methylamino) -3'-methylspiro [phthalide-3,9'-xanthene] -2 '
Fluorane dyes such as -ylamino] phenyl} propane. Of course, it is not limited to these dyes,
A combination of two or more dyes is also possible.

Various kinds of compounds are known as colorants used in combination with the above basic dyes, and examples thereof include the following. 4-tert-butylphenol, α-naphthol, β-naphthol, 4-acetylphenol,
4-tert-octylphenol, 4,4'-sec-butylidene diphenol, 4-phenylphenol, 4,
4'-dihydroxy-diphenylmethane, 4,4'-isopropylidenediphenol, hydroquinone, 4,
4'-cyclohexylidene diphenol, 4,4'-
(1,3-dimethylbutylidene) bisphenol, 2,
2-bis (4-hydroxyphenyl) -4-methylpentane, 4,4'-dihydroxydiphenyl sulfide, 4,4'-thiobis (6-tert-butyl-3-methylphenol), 4,4'-dihydroxydiphenyl Sulfone, 2,4'-dihydroxydiphenyl sulfone,
4-hydroxy-4'-methyldiphenyl sulfone, 4
-Hydroxy-4'-methoxydiphenyl sulfone, 4
-Hydroxy-4'-isopropoxydiphenyl sulfone, 4-hydroxy-3 ', 4'-trimethylene diphenyl sulfone, 4-hydroxy-3', 4'-tetramethylene diphenyl sulfone, 3,4-dihydroxy-
4'-methyldiphenyl sulfone, bis (3-allyl-
4-hydroxyphenyl) sulfone, 1,3-di [2-
(4-hydroxyphenyl) -2-propyl] benzene, hydroquinone monobenzyl ether, bis (4-hydroxyphenyl) acetic acid butyl ester, 4-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,4,4'-trihydroxy Benzophenone,
2,2 ', 4,4'-tetrahydroxybenzophenone, dimethyl 4-hydroxyphthalate, methyl 4-hydroxybenzoate, ethyl 4-hydroxybenzoate, 4-
Propyl hydroxybenzoate, sec-butyl 4-hydroxybenzoate, pentyl 4-hydroxybenzoate, 4
Phenyl hydroxybenzoate, benzyl 4-hydroxybenzoate, tolyl 4-hydroxybenzoate, chlorophenyl 4-hydroxybenzoate, phenylpropyl 4-hydroxybenzoate, phenethyl 4-hydroxybenzoate, 4-hydroxybenzoic acid-p- Chlorobenzyl, 4
-Hydroxybenzoic acid-p-methoxybenzyl, novolac type phenolic resin, phenolic compounds such as phenolic 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, 3,5-di-tert-butylsalicylic acid, 3-benzylsalicylic acid, 3- (α-methylbenzyl) salicylic acid, 3-chloro-5- (α-methylbenzyl) salicylic acid, 3-phenyl −5- (α,
α-Dimethylbenzyl) salicylic acid, 3,5-di-α-
Aromatic carboxylic acids such as methylbenzyl salicylic acid, and organic acidic substances such as salts of these phenolic compounds and aromatic carboxylic acids with polyvalent metals such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin and nickel etc. Of course, the above-mentioned coloring agents can also be used as needed.
One or more species can be used in combination.

The use ratio of the basic dye and the color developing agent 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, but in general, the basic dye 1 is used.
About 100 to 700 parts by weight, preferably about 150 to 400 parts by weight, of the coloring agent is used with respect to 00 parts by weight. The coating liquid containing these is generally prepared by dispersing water with a dispersion medium, a basic dye, a colorant together or separately by a stirring / grinding machine such as a ball mill, attritor, or sand mill. However, in such a coating liquid, starches, hydroxyethyl cellulose, and
Methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, polyvinyl alcohol, styrene / maleic anhydride copolymer salt, styrene /
Acrylic acid copolymer salt, styrene-butadiene copolymer emulsion and the like are added in an amount of 10 to 40% by weight, preferably 15 to 30% by weight, based on the total solid content.

Various auxiliaries can be further added to the coating liquid, for example, dioctylsulfosuccinic acid sodium salt, dodecylbenzenesulfonic acid sodium salt,
Examples thereof include dispersants such as lauryl alcohol sulfate / sodium salt and fatty acid metal salt, defoaming agents, fluorescent dyes, and coloring dyes. Further, in order to improve the adhesion of dust to the recording head, kaolin, clay, talc, calcium carbonate, calcined clay, titanium oxide, diatomaceous earth, fine anhydrous silica, inorganic pigments such as activated clay, styrene microballs, nylon powder, polyethylene Powder, urea
Organic pigments such as formalin resin filler and raw starch particles can also be added. Further, a dispersion liquid or emulsion of stearic acid, polyethylene, carnauba wax, paraffin wax, zinc stearate, calcium stearate, ester wax or the like may be added so that sticking does not occur due to contact with a recording device or recording head.

Further, in the heat-sensitive recording material of the present invention, fatty acid amides such as stearic acid amide, stearic acid methylene bisamide, oleic acid amide, palmitic acid amide, and coconut fatty acid amide are used as long as the desired effects of the present invention are not impaired. , 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 4,4'-butylidenebis (6-tert-butyl-3-methylphenol), 1,1,3-tris (2-methyl) -4-hydroxy-5-tert-butylphenyl) butane, 1,1,3-
Hindered phenols such as tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, p
-Benzylbiphenyl, p- (4-tolyloxy) biphenyl, 1,5-bis (4-methoxyphenoxy) -3
-Oxa-pentane, 1,2-bis (phenoxy) ethane, 1,2-bis (4-methylphenoxy) ethane,
1,2-bis (3-methylphenoxy) ethane, 1-
Ethers such as (2-methylphenoxy) -2- (4-methoxyphenoxy) ethane, 2-naphtholbenzyl ether, dibenzyl terephthalate, 1-hydroxy-2-naphthoic acid phenyl ester, oxalic acid dibenzyl ester, oxalic acid Esters such as di (4-methylbenzyl) ester and oxalic acid di (4-chlorobenzyl) ester, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2-hydroxy-4-benzyloxybenzophenone It is also possible to use an ultraviolet absorber such as the above and various known heat-fusible substances together as a sensitizer. Among these heat-fusible substances, 1,2-bis (3-methylphenoxy) ethane, 1,2-bis (phenoxy) ethane, 1- (2-methylphenoxy) -2-
(4-methoxyphenoxy) ethane, oxalic acid dibenzyl ester, oxalic acid di (4-methylbenzyl) ester, oxalic acid di (4-chlorobenzyl) ester, p-
Benzylbiphenyl, p- (4-tolyloxy) biphenyl, and 1,5-bis (4-methoxyphenoxy)-
3-Oxa-pentane is more preferable because it exhibits a particularly excellent sensitizing effect in relation to a specific storage stability improver.
The amount of the heat-fusible substance used is not particularly limited, but is generally 50 to 1000 parts by weight, preferably 100 to 500 parts by weight with respect to 100 parts by weight of the basic dye.
It is desirable to use it in the range of parts by weight.

The method for forming the recording layer is not particularly limited, and the coating liquid for the heat-sensitive recording layer is applied onto a support having an intermediate layer formed thereon, for example, an air knife coater, a blade coater,
Bar coater, gravure coater, curtain coater,
It is formed by a method such as coating and drying with a suitable coating device such as a short dwell coater. Further, the coating amount of the coating liquid is not particularly limited, and generally 2 to 2 in dry weight.
12 g / m ² approximately, it is preferably adjusted in the range of about 2 to 8 g / m ^2.

After coating and drying the intermediate layer and the recording layer, a smoothing treatment such as super calendering can be applied if necessary. Further, it is possible to provide an overcoat layer on the recording layer for the purpose of protecting the recording layer, and to provide a backing layer on the support or to apply an adhesive treatment to various overcoat layers in the field of manufacturing thermal recording media. Known techniques can be added.

The thermal recording material of the present invention thus obtained is
Since an intermediate layer containing a graft copolymer of a specific oil-absorbing pigment, polyvinyl alcohol and a copolymer of (acrylamide / acrylic acid / acrylonitrile) as a main component is provided between the support and the thermosensitive recording layer. Excellent pixel reproducibility in all areas from low density to high density, high recording density, and excellent surface strength of the recording material, so head dust and paper dust generation during cutting are effective. It is a thermal recording material that is effectively suppressed and has an excellent quality balance.

[0020]

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 represent parts by weight and% by weight, respectively.

Example 1 [Preparation of coating liquid for intermediate layer] Amorphous silica (oil absorption: 150 ml)
/ 100g) 100 parts, 30 parts of a 10% aqueous solution of a graft copolymer of polyvinyl alcohol and a (acrylamide / acrylic acid / acrylonitrile) copolymer (Polymaron-1560, manufactured by Arakawa Chemical Co., Ltd.) and SBR latex (solid content: 10 parts of 50%) was mixed so that the solid content was 30% to prepare an intermediate layer coating liquid. [Formation of Intermediate Layer] The obtained intermediate layer coating liquid was used to weigh 50 g / m 2.
^{The high-} quality paper of No. ² was coated and dried with an air knife coater so that the coating amount after drying was 8 g / m ² (thickness: 13 μm).

[Preparation of coating liquid for recording layer] Preparation of liquid A 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-phenylaminofluorane 10 parts 1,2-bis (4-methylphenoxy) Ethane 20 parts Methylcellulose 5% aqueous solution 15 parts Water 80 parts This composition was ground by a sand mill until the average particle size became 0.8 μm.

Preparation of Solution B 4,4′-Isopropylidenediphenol 30 parts Methylcellulose 5% aqueous solution 30 parts Water 70 parts This composition was ground with a sand mill until the average particle size became 0.8 μm.

A coating solution for a recording layer is prepared by stirring and mixing 125 parts of solution A, 130 parts of solution B, 30 parts of silicon oxide pigment (oil absorption 180 ml / 100 g), 150 parts of 20% aqueous solution of oxidized starch, and 55 parts of water. did.

[Formation of Recording Layer] The above-mentioned coating liquid for recording layer is applied onto the above-mentioned intermediate layer with an air knife coater so that the coating amount after drying is 5 g / m ^2, and dried to obtain a thermosensitive recording paper. It was

Example 2 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that calcined clay (oil absorption 85 ml / 100 g) was used in place of the amorphous silica in the preparation of the coating liquid for the intermediate layer.

Example 3 10 of graft copolymer of polyvinyl alcohol and (acrylamide / acrylic acid / acrylonitrile) copolymer (Polymaron-1560, manufactured by Arakawa Chemical Co., Ltd.)
% Thermal paper was obtained in the same manner as in Example 1 except that the amount of the aqueous solution was 200 parts.

Example 4 In the preparation of solution A of the recording layer coating liquid, 3-di (N-butyl) was used instead of 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-phenylaminofluorane. ) A thermal recording paper was obtained in the same manner as in Example 1 except that amino-6-methyl-7-phenylaminofluorane was used.

Comparative Example 1 Instead of amorphous silica, clay (oil absorption 20 ml / 1
A thermosensitive recording paper was obtained in the same manner as in Example 1 except that 100 g) was used.

Comparative Example 2 Instead of a graft copolymer of polyvinyl alcohol and (acrylamide / acrylic acid / acrylonitrile) copolymer (Polymaron-1560, manufactured by Arakawa Chemical Co., Ltd.), polyvinyl alcohol (degree of polymerization: 1000, saponification) Thermal recording paper was obtained in the same manner as in Example 1 except that the temperature was 98%).

The five kinds of thermal recording papers thus obtained were
A thermal printer (SONY, UP-701 type video printer) was used to record with a print pulse time of 3 ms and 8 ms, and the recorded density was recorded with a Macbeth densitometer (RD-100
R type, using an amber filter) and the results are shown in Table 1. In addition, the reproducibility of the print pixels, the suitability for cutting, and the state of head residue adhesion were evaluated, and the results are also shown in Table 1.

[0032]

[Table 1]

The reproducibility of the printed pixels was evaluated by the ratio of the area of the printed dots to the area of one dot of the thermal head (dot reproducibility), and the evaluation criteria were as follows. ◎ ・ ・ ・ ・ 86% or more ○ ・ ・ ・ ・ 76-85% △ ・ ・ ・ ・ 70-75% × ・ ・ ・ 69% or less

The cutting suitability was evaluated by the generation of paper dust when the recording portion and the blank portion of the recording paper were cut by a cutter, and the evaluation criteria were as follows. ◎ ・ ・ ・ ・ No paper dust is generated or the recording layer is peeled off. ○: No paper dust was generated, but the recording layer was slightly peeled off. × ・ ・ ・ ・ Paper powder is remarkably generated and the recording layer is often peeled off.

Further, regarding the head residue, a printing rate of 1 was obtained by using a heat-sensitive fax machine (NEFAX-27).
The occurrence of head shavings after copying 10 sheets at 00% was evaluated, and the evaluation criteria were as follows. ◎ ・ ・ ・ ・ Heads are not seen at all. ○: A small amount of head dust is seen. × ・ ・ ・ ・ Heads are remarkably generated.

[0036]

As is clear from the results of Table 1, the thermosensitive recording medium of the present invention is excellent in reproducibility of print pixels in any area from low density to high density, and has high recording density. The recording material was excellent in cutting suitability and also excellent in head scrap.

Claims (3)

[Claims] 1. A heat-sensitive recording material comprising a support and a heat-sensitive recording layer, wherein an oil absorption is 80 m between the support and the recording layer.
Pigment and polyvinyl alcohol with 1 / 100g or more (acrylamide / acrylic acid / acrylonitrile)
A thermosensitive recording medium comprising an intermediate layer containing a graft copolymer with a copolymer as a main component. 2. The heat-sensitive recording material according to claim 1, wherein the pigment having an oil absorption of 80 ml / 100 g or more is one kind selected from amorphous silica, aluminum silicate and calcined clay. 3. The heat-sensitive recording material according to claim 1, wherein 2 to 30 parts by weight of a graft copolymer of polyvinyl alcohol and a (acrylamide / acrylic acid / acrylonitrile) copolymer is used with respect to 100 parts by weight of the pigment.