JPH1035103A - Thermosensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosensitive recording material which has good coloring properties, dot reproducibility, head matching properties, and chemical resistance. SOLUTION: In a thermosensitive recording material made by laminating an intermediate layer containing a non-expandable plastic hollow particulates with an average grain size of 2 to 10μm and hollowness of 90% or more, a thermosensitive coloring layer whose main components are a leuco dye and a developer, and a protective layer whose main components are a pigment and a resin, on a support in sequence, the protective layer contains aluminum hydroxide as a pigment and zinc stearate as a solute, which account for 75 to 125wt.% and 5 to 15wt.%, respectively.

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 improved properties by providing an elastic intermediate layer between a support and a heat-sensitive coloring layer and a protective layer on the heat-sensitive coloring layer. Related to recording materials.

[0002]

2. Description of the Related Art Recently, various recording materials have been researched, developed, and put to practical use in the information recording field in accordance with social demands such as diversification and increase of information, resource saving, and non-pollution. Above all, the thermosensitive recording material is (1) that a color image is recorded only by heating and a complicated developing step is unnecessary, (2) that it can be manufactured using a relatively simple and compact device, and that the obtained recording is further improved. (3) In many cases, paper is used as a support. In this case, not only the cost of the support is low but also the feeling of the obtained recording material. Because of the advantages of being close to plain paper, such as computer output, printers such as calculators, recorders for medical measurement, low and high-speed facsimile, automatic ticket vending machines, thermal copying, POS systems Are widely used in the label field and the like of the beam.

The above-mentioned thermosensitive recording material is usually produced by applying and drying a thermosensitive coloring layer solution containing a coloring component capable of causing a coloring reaction by heating on a support such as paper, synthetic paper or synthetic resin film. The heat-sensitive recording material thus obtained is heated by a hot pen or a thermal head to record a color image. Conventional examples of such a heat-sensitive recording material include, for example, Japanese Patent Publication No. 43-4160.
Or the heat-sensitive recording material disclosed in JP-B-45-14039. However, such a conventional heat-sensitive recording material has, for example, a low thermal response, and does not provide a sufficient color density during high-speed recording. .

As a method for remedying such a defect, for example, Japanese Patent Application Laid-Open No. 49-38424 discloses a method of using a nitrogen-containing compound such as acetamide, stearamide, m-nitroaniline, dinitrile phthalate, etc.
No. 46 discloses acetoacetic anilide in Japanese Patent Laid-Open No. 53-1.
No. 1036 discloses an N, N-diphenylamine derivative,
Benzamide derivatives and carbazole derivatives are disclosed in
JP-A-3-39139 discloses an alkylated biphenyl and a biphenylalkane, and JP-A-56-144193 discloses a method of increasing the speed and sensitivity by incorporating a p-hydroxybenzoic acid ester derivative. Although disclosed, at present, no satisfactory results have been obtained by any of the methods. As another method, Japanese Patent Application Laid-Open No. 56-164890 discloses a method in which a leuco dye having a high melting point is made amorphous to lower the melting point and increase the sensitivity. However, since the surface of the amorphized dye is activated and has high reactivity, there is a problem that the fogging or background fog of the thermosensitive coloring liquid or the thermosensitive recording material is large and the whiteness is poor.

[0005] Therefore, in order to suppress background fog and enhance dynamic color development sensitivity, the thermal conductivity of the support is set to 0.04 Kca.
1 / mh ° C. or lower (Japanese Patent Laid-Open No. 55-164192) or providing a layer mainly composed of fine hollow sphere particles on a support (Japanese Patent Laid-Open Nos. 59-5093 and 59-225).
No. 987) and a method using non-foamable fine hollow particles of 5 μm or less made of a thermoplastic resin for the intermediate layer (Japanese Patent Application Laid-Open No. 62-5886).
Has been proposed. However, Japanese Patent Application Laid-Open No. 55-16 / 1979
No. 4192, JP-A-59-5093, etc., the heat-sensitive recording material has insufficient foaming properties and lacks flexibility in the wall material, has insufficient heat insulating properties, or has a problem with thermal heads. In some cases, the adhesiveness to the heat-sensitive recording material may be insufficient, and it cannot be said that satisfactory results have been obtained.
The thermal recording material proposed in Japanese Patent No. 886 does not provide satisfactory results.

In order to improve the fading of an image with a chemical such as a plasticizer, which is one of the drawbacks of the heat-sensitive recording material, many proposals have been made to provide a protective layer on the heat-sensitive coloring layer. In such a case, there are problems such as a decrease in dynamic sensitivity and deterioration in dot reproducibility. Therefore, in order to improve this point, in the case of a thermosensitive recording material in which an intermediate elastic layer, a thermosensitive coloring layer and a protective layer are sequentially laminated on a support, the protective layer has an average particle diameter of 0.1 to 1.5 μm. It has been proposed that aluminum be contained (JP-A-5-318928) and that the Bekk smoothness of the surface of the protective layer be 500 to 1,200 seconds (JP-A-6-191157).
Certainly, these heat-sensitive recording materials have high sensitivity and high definition, and are also excellent in chemical resistance to plasticizers and the like. However, when aluminum hydroxide is used for the protective layer, the oil absorption of aluminum hydroxide is high. Since the amount is small, a problem occurs in the head matching property, and when the smoothness of the protective layer is reduced, the coloring sensitivity and the definition cannot be said to be sufficient.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to use non-expandable fine hollow particles having an average particle diameter of 2 to 10 .mu.m and a hollow ratio of 90% or more for a middle layer, and to provide a protective layer with chemical resistance. It is an object of the present invention to provide a heat-sensitive recording material using excellent aluminum hydroxide, having high sensitivity, high definition, excellent chemical resistance, and further having improved head matching such as sticking.

[0008]

According to the present invention, first, on a support, an average particle diameter is 2 to 10 μm and a hollowness is 9 μm.
A thermosensitive recording material in which an intermediate layer containing 0% or more of non-foamable plastic hollow fine particles, a thermosensitive coloring layer mainly containing a leuco dye and a developer, and a protective layer mainly containing a pigment and a resin are sequentially laminated. In the protective layer contains aluminum hydroxide as a pigment, zinc stearate as a lubricant,
In addition, there is provided a thermosensitive recording material characterized in that the weight ratio to the resin is 75 to 125% by weight of aluminum hydroxide and 5 to 15% by weight of zinc stearate.
Second, the Bekk smoothness of the protective layer surface is 1000 to 3
The heat-sensitive recording material according to the first aspect, which is 2,000 seconds. Third, a copolymer of isobutylene and maleic anhydride was used as a resin in the protective layer.
The heat-sensitive recording material according to the first or second aspect is characterized by containing 0% by weight or more. Fourthly, there is provided the heat-sensitive recording material as described in the first, second or third aspect, wherein the protective layer contains 1 to 5% of dialkyl succinate based on the resin.

That is, the heat-sensitive recording material of the present invention comprises an intermediate layer containing non-foamable plastic hollow fine particles having an average particle diameter of 2 to 10 μm and a hollowness of 90% or more on a support;
The thermosensitive coloring layer mainly composed of a leuco dye and a developer, and a resin, aluminum hydroxide (pigment) and zinc stearate (lubricant), and the weight ratio to the resin is:
Since a protective layer having 75 to 125% by weight of aluminum hydroxide and 5 to 15% by weight of zinc stearate is sequentially laminated, high sensitivity, high definition, and chemical resistance are achieved. And the head matching such as sticking is also improved.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in more detail. In the present invention, the protective layer mainly composed of a pigment and a resin contains aluminum hydroxide as a pigment and zinc stearate as a lubricant. The weight ratio of aluminum hydroxide to the resin is 75 to 125% by weight, and stearic acid is used. The zinc content is 5 to 15% by weight, which solves the above-mentioned problem of the present invention.

The Beck smoothness of the surface of the protective layer is 1000 to 3
000 seconds is preferable, and 1000 seconds or less,
Sensitivity and definition are insufficient, and sticking occurs at 3000 seconds or more. As the resin for the protective layer, a binder such as a conventionally known water-soluble polymer or aqueous polymer emulsion described below is used, and preferably contains 30% by weight or more of a copolymer of isobutylene and maleic anhydride. It is desirable to have done. Further, although a known surfactant is used for the protective layer, it is preferable that the dialkyl succinate is contained in an amount of 1 to 5% based on the resin.

The average particle size of the aluminum hydroxide used in the protective layer of the present invention is 0.1 to 1.5 μm.
The usage ratio of the resin and aluminum hydroxide is 0.75 to 1.25 parts by weight of aluminum hydroxide per 1 part by weight of the resin. If it is less than 0.75 parts by weight, the effect of preventing sticking is insufficient, and if it exceeds 1.25 parts by weight, the chemical resistance is insufficient.

In the protective layer of the present invention, zinc stearate is used as a lubricant. The proportion of the resin and zinc stearate used is 0.05 to 0.15 parts by weight of zinc stearate based on 1 part by weight of the resin. If the amount is less than 0.05 part by weight, the effect as a lubricant is insufficient, while if it exceeds 0.15 part by weight, chemical resistance is insufficient and sticking occurs.

[0014] As an auxiliary additive component of the protective layer, for example, a filler, a heat-fusible substance or the like can be used. Specific examples thereof include the same ones as exemplified in the thermosensitive coloring layer described later.

In the present invention, the average particle size is 2 to 10
An intermediate layer containing non-foamable plastic hollow fine particles having a diameter of 90 μm and a hollowness of 90% or more is provided. This intermediate layer acts as a heat insulating layer to improve the sensitivity by efficiently utilizing the thermal energy from the thermal head and the like, and the heat of the thermal head when printing on one side is applied to the heat-sensitive coloring layer on the other side. To prevent color development.

The hollow particles used in the intermediate layer of the present invention are fine hollow particles which have a thermoplastic resin as a shell and contain air or other gas therein and are already in a foamed state. Those having a size of 2 to 10 μm, preferably 3 to 10 μm are used. Average particle size (particle outer diameter)
Is less than 2 μm, there is a problem in production such as difficulty in providing an arbitrary degree of hollowness, and the cost is difficult.
If the thickness is larger than 0 μm, the smoothness of the surface after coating and drying is reduced, so that the adhesion to the thermal head is reduced and the effect of improving sensitivity is reduced. Therefore, it is desirable that such a particle distribution is such that the particle diameter is within the above-mentioned range and the distribution peak is small and uniform.

Further, the fine hollow particles used in the present invention have a hollowness of 90% or more. This hollowness is 9
If it is less than 0%, the heat insulating property is insufficient, so that the thermal energy from the thermal head is released through the support to the outside of the heat-sensitive recording material, and the sensitivity improving effect becomes insufficient. In addition, the hollowness here is the ratio of the outer diameter and the inner diameter of the hollow particles,
It is displayed by the following formula. Hollowness = {(inner diameter of hollow particles) / (outer diameter of hollow particles)}
× 100 (%)

The fine hollow particles used in the present invention have a shell made of a thermoplastic resin as described above. Examples of the resin include polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, and polyvinyl acetate. Acrylic acid esters, polyacrylonitrile, polybutadiene, and copolymer resins thereof are exemplified. Among these,
Particularly, a copolymer resin mainly composed of vinylidene chloride and acrylonitrile is preferable.

In order to provide the above-mentioned intermediate layer on a support,
The resin micro hollow body is obtained by dispersing in water together with a known binder such as a water-soluble polymer or an aqueous polymer emulsion, coating the solution on the surface of a support and drying. Specific examples of the binder in this case include water-soluble polymers such as polyvinyl alcohol, starch and derivatives thereof, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, cellulose derivatives such as ethylcellulose, sodium polyacrylate,
Polyvinyl pyrrolidone, acrylamide / acrylic acid ester copolymer, acrylamide / acrylic acid ester / methacrylic acid terpolymer, styrene / maleic anhydride copolymer alkaline salt, isobutylene / maleic anhydride copolymer alkaline salt, polyacrylamide , Sodium alginate, gelatin, casein and the like. Also,
Examples of the aqueous polymer emulsion include latexes such as styrene / butadiene copolymer and styrene / butadiene / acrylic copolymer, vinyl acetate resin, vinyl acetate / acrylic copolymer, and styrene / acrylic ester copolymer. And emulsions of acrylic acid ester resins and polyurethane resins.

In the intermediate layer of the present invention, the plastic spherical hollow particles and the binder resin may be used together with, if necessary, auxiliary additives commonly used in this type of heat-sensitive recording material, such as fillers and heat-fusible materials. , A surfactant and the like can be used. In this case, specific examples of the filler and the heat-fusible substance include various substances described below in relation to the thermosensitive coloring layer component.

The leuco dyes used in the present invention may be used alone or as a mixture of two or more. As such leuco dyes, those applied to this type of recording material are arbitrarily applied. Methanephthalide,
Triallylmethane type, fluoran type, phenothidiane type, thioferoran type, xanthene type, indophthalyl type, spiropyran type, azaphthalide type, chromenopyrazole type, methine type, rhodamine anilinolactam type,
Leuco-containing substances such as rhodamine lactams, quinazolines, diazaxanthenes and bislactones are preferably used. Examples of such compounds include, for example, those shown below.

3,3-bis (p-dimethylaminophenyl) -phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-diethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-dibutylaminophenyl) phthalide, 3-cyclohexylamino-6-chlorofluoran, 3 -Dimethylamino-5,
7-dimethylfluoran, 3- (N-methyl-N-isoamylamino) -6-methyl-7-anilinofluoran, 3- (N-methyl-N-isobutylamino) -6
Methyl-7-anilinofluoran, 3- (Np-tolyl-N-ethylamino) -6-methyl-7-anilinofluoran, 3- (N-methyl-N-amylamino) -6
-Methyl-7-anilinofluoran, 3- (N, N-di-n-amylamino) -6-methyl-7-anilinofluoran, 3- (N-methyl-N-cyclohexylamino) -6 Methyl-7-anilinofluoran, 3- (N
-Methyl-N-iso-propylamino) -6-methyl-7-anilinofluoran, 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluoran, 3- Diethylamino-7,8-benzfluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-7-methylfluoran, 3-
Diethylamino-6-methyl-7-chlorofluoran,
3-pyrrolidino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (m-trichloroanilino) fluoran, 3-diethylamino-7
-(O-chloroanilino) fluoran, 3-dibutylamino-7- (o-chloroanilino) fluoran, 3-diethylamino-6-methyl-7-anilinofluoran,
3-dibutylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (2 ′,
4'-dimethylanilino) fluoran, 3- (N, N-
Diethylamino) -5-methyl-7- (N, N-dibenzylamino) fluoran, benzoylleucomethylene blue, 6'-chloro-8'-methoxybenzoindolinospiropyran, 6'-bromo-8'-methoxybenzoindolino Spiropyran, 3- (2'-hydroxy-4 '
-Dimethylaminophenyl) -3- (2'-methoxy-
5'-chlorophenyl) phthalide, 3- (2'-hydroxy-4'-dimethylaminophenyl) -3- (2'-
Methoxy-5'-nitrophenyl) phthalide, 3-
(2'-hydroxy-4'-diethylaminophenyl)
-3- (2'-methoxy-5'-methylphenyl) phthalide, 3- (2'-methoxy-4'-dimethylaminophenyl) -3- (2'-hydroxy-4'-chloro-
5'-methylphenyl) phthalide, 3-morpholino-7
-(N-propyltrifluoromethylanilino) fluoran, 3-pyrrolidino-7-trifluoromethylanilinofluoran, 3-diethylamino-5-chloro-7-
(N-benzyl-trifluoromethylanilino) fluoran, 3-pyrrolidino-7- (di-p-chlorophenyl) methylaminofluoran, 3-diethylamino-5
-Chloro-7- (α-phenylethylamino) fluoran, 3- (N-ethyl-Np-toluidino) -7-
(Α-phenylethylamino) fluoran, 3-diethylamino-7- (o-methoxycarbonylphenylethylfluoran, 3-diethylamino-5-methyl-7-
(Α-phenylethylamino) fluoran, 3-diethylamino-7-piperidinoaminofluoran, 2-chloro-3- (N-methyltoluidino) -7- (p-N-butylanilino) fluoran, 3,6-bis (Dimethylamino) fluorenespiro (9,3 ')-6'-dimethylaminophthalide, 3- (N-ethyl-N-cyclohexylamino) -5,6-benzo-7-α-naphthylamino-4'- Bromofluorane, 3-diethylamino-6-
Chloro-7-anilinofluoran, 3- (N-ethyl-
N-2-ethoxypropylamino) -6-methyl-7-
Anilinofluoran, 3- (N-ethyl-N-tetrafurfurylamino) -6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-mesitidino-4 ′, 5′-benzo Fluoran, 3- (p-dimethylaminophenyl) -3- {1,1-bis (p-dimethylaminophenyl) ethylene-2-yl} phthalide, 3-
(P-dimethylaminophenyl) -3- {1,1-bis (p-dimethylaminophenyl) ethylene-2-yl}
-6-dimethylaminophthalide, 3- (p-dimethylaminophenyl) -3- (1-p-dimethylaminophenyl-1-phenylethylene-2-yl) phthalide, 3-
(P-dimethylaminophenyl) -3- (1-p-dimethylaminophenyl-1-p-chlorophenylethylene-2-yl) -6-dimethylaminophthalide, 3-
(4'-dimethylamino-2'-methoxy) -3-
(1 "-p-dimethylaminophenyl-1" -p-chlorophenyl-1 ", 3" -butadiene-4 "-yl) benzophthalide, 3- (4'-dimethylamino-2'-benzyloxy) -3- (1 "-p-dimethylaminophenyl-1" -phenyl-1 ", 3" -butadiene-4 "
-Yl) benzophthalide, 3-dimethylamino-6-dimethylamino-fluorene-9-spiro-3 '(6'-
Dimethylamino) phthalide, 3,3-bis (2- (p-
Dimethylaminophenyl) -2- (p-methoxyphenyl) ethenyl l-4,5,6,7-tetrachlorophthalide, 3-bis {1,1-bis (4-pyrrolidinophenyl) ethylene-2-yl ｝ -5,6-dichloro｝ 4,7
-Dibromophthalide, bis (p-dimethylaminostyryl) -1-naphthalenesulfonylmethane, bis (p-dimethylaminostyryl) -1-p-tolylsulfonylmethane and the like.

In the present invention, various compounds having an electron accepting property, such as a phenolic compound, may be used as a color developer.
A thiophenol compound, a thiourea derivative, an organic acid and a metal salt thereof can be used. Specific examples thereof include the following, but are not limited thereto.

4,4'-isopropylidene diphenol, 4,4'-isopropylidenebis-o-methylphenol, 4,4'-sec-butylidenebisphenol, 4,4'-isopropylidenebis (2-tert −
Butylphenol, zinc p-nitrobenzoate, 1,3
5-tris (4-tert-butyl-3-hydroxy-
2,6-dimethylbenzyl isocyanuric acid, 2,2-
(3,4′-dihydroxyphenyl) propane, bis (4-hydroxy-3-methylphenyl) sulfide,
4- (β- (p-methoxyphenoxy) ethoxy) salicylic acid, 1,7-bis (4-hydroxyphenylthio)
3,5-dioxaheptane, 1,5-bis (4-hydroxyphenylthio) -3-oxabentan, monobenzyl phthalate monocalcium salt, 4,4′-cyclohexylidenediphenol, 4,4′-isopropyl Redidenbis (2-chlorophenol), 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 4,4′-butylidenebis (6-tert-butyl-2-methylphenol), 1,1,1 3-Tris (2
-Methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4,4'-thiobis (6-tert-butyl-2-methylphenol), 4,4'-diphenolsulfone, 4-isopropoxy-4'- Hydroxydiphenylsulfone, 4-benzyloxy-4′-hydroxydiphenylsulfone, 4,4′-diphenolsulfoxide, isopropyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, benzyl protocatechuate,
Stearyl gallate, lauryl gallate, octyl gallate, 1,3-bis (4-hydroxyphenylthio) propane, N, N'-diphenylthiourea, N, N'-di (m-chlorophenyl) thiourea, salicyl Anilide,
Methyl bis- (4-hydroxyphenyl) acetate, benzyl bis (4-hydroxyphenyl) acetate, 1,3-bis (4-hydroxyphenyl) benzene, 1,4-bis (4-hydroxyphenyl) benzene, 2,4 '-Diphenolsulfone, 2,2'-diallyl-4,4'-hydroxyphenylsulfone, 3,4-dihydroxy-
4'-methyldiphenyl sulfone, zinc 1-acetyloxy-2-naphthoate, zinc 2-acetyloxy-3-naphthoate, zinc 2-acetyloxy-1-naphthoate, α, α-bis (4-hydroxyphenyl ) Α-Methyltoluene, antipyrine complex of zinc thiocyanate, tetrabromobisphenol A, tetrabromobisphenol S, 4,4′-thiobis (2-methylphenol), 4,4′-thiobis: (2-chlorophenol)
etc.

In order to produce the heat-sensitive recording material of the present invention, a leuco dye, a developer and other auxiliaries may be supported on a support. As the binder in this case, various conventional binders can be appropriately used, and specific examples thereof include the same ones as exemplified in the above-mentioned intermediate layer coating.

Further, in the thermosensitive coloring layer of the present invention, various heat-fusible substances can be used in combination as a sensitivity improving agent. Specific examples thereof include the following, but are not limited thereto. I don't know.

Fatty acids such as stearic acid and behenic acid; fatty acid amides such as stearic acid amide and palmitic acid amide; zinc stearate; aluminum stearate;
Fatty acid metal salts such as calcium stearate, zinc palmitate, and zinc behenate, p-benzylbiphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, β
-Phenyl naphthoate, phenyl 1-hydroxy-2-naphthoate, methyl 1-hydroxy-2-naphthoate,
Diphenyl carbonate, gliacol carbonate, dibenzyl terephthalate, dimethyl terephthalate,
1,4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 1,4-dibenzyloxynaphthalene, 1,2
-Diphenoxyethane, 1,2-bis (3-methylphenoxy) ethane, 1,2-bis (4-methylphenoxy) ethane, 1,4-diphenoxybutane, 1,4-diphenoxy-2-butene, 1 , 2-bis (4-methoxyphenylthio) ethane, dibenzoylmethane, 1,4-
Diphenylthiobutane, 1,4-diphenylthio-2-
Butene, 1,3-bis (2-vinyloxyethoxy) benzene, 1,4-bis (2-vinyloxyethoxy) benzene, p- (2-vinyloxyethoxy) biphenyl, p-aryloxybiphenyl, p-propa Gyloxybiphenyl, dibenzoyloxymethane, dibenzoyloxypropane, dibenzyldisulphide, 1,1
-Diphenylethanol, 1,1-diphenylpropanol, p-benzyloxybenzyl alcohol, 1,3
-Phenoxy-2-propanol, N-octadecylcarbamoyl-p-methoxycarbonylbenzene, N-octadecylcarbamoylbenzene, 1,2-bis (4-
Methoxyphenoxy) propane, 1,5-bis (4-methoxyphenoxy) -3-oxapentane, dibenzyl oxalate, bis (4-methylbenzyl) oxalate, bis (4-chlorobenzyl) oxalate and the like.

When a heat-sensitive recording material is obtained according to the present invention, if necessary, together with a leuco dye and a developer, additional components commonly used in this type of heat-sensitive recording material, such as a filler,
A surfactant, a lubricant, a pressure coloring inhibitor and the like can be used in combination. In this case, as a filler, for example, inorganic fine powder such as calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, kaolin, talc, surface-treated calcium and silica, and urea -Fine organic powders such as formalin resin, styrene / methacrylic acid copolymer, polystyrene resin, vinylidene chloride resin, etc., and as the lubricant, higher fatty acids and metal salts thereof, higher fatty acid amides,
Examples include higher fatty acid esters, various types of animal, vegetable, mineral or petroleum waxes.

In the present invention, a layer containing a pigment, a binder, a heat-fusible substance and the like can be provided between the intermediate layer and the thermosensitive coloring layer, if necessary, as another intermediate layer. .

[0030]

Next, the present invention will be described in more detail with reference to examples. All parts and percentages shown below are based on weight.

<Preparation of heat-sensitive coloring layer coated paper> [Solution A] 20 parts of 3-dibutylamino-6-methyl 20 parts of 10% aqueous solution of 7-anilinofluoran polyvinyl alcohol 60 parts of water

[Solution B] 4-Isopropoxy-4'-hydroxydiphenylsulfone 10 parts 10% aqueous solution of polyvinyl alcohol 25 parts Calcium carbonate 15 parts Water 50 parts

[Liquid C] 20 parts of aluminum hydroxide {manufactured by Showa Denko KK: Hijilite H43M} 10 parts aqueous solution of polyvinyl alcohol 20 parts Water 60 parts

The mixture having the above composition was dispersed using a sand mill so that the average particle diameter was 2 μm or less, respectively, to prepare [Solution A], [Solution B] and [Solution C].

[Solution D] Micro hollow particles (copolymer resin containing mainly 24 parts of vinylidene chloride and acrylonitrile) (solid content: 41%, average particle size: 5 μm, hollowness: 92%) Styrene / butadiene copolymer latex 10 parts (solid content 47.5%)

The mixture having the above composition was stirred and dispersed to prepare an intermediate layer forming liquid, which was then mixed with a commercially available high-quality paper (with a basis weight of 52 g).
/ M ² ) was applied to the surface so as to have a dry weight of 5 g / m ² and dried to obtain an intermediate layer coated paper.

Next, the above [Solution A] and [Solution B] were mixed and stirred at a weight ratio of 1:10 to prepare a thermosensitive coloring layer forming solution, which was dried on the surface of the intermediate layer coated paper. The coated paper was dried so as to have a weight of 5 g / m ² to obtain a thermosensitive coloring layer coated paper.

Examples 1 to 5 and Comparative Examples 1 to 4 [Liquid C], 10% aqueous solution of polyvinyl alcohol, epichlorohydrin resin (12.5%), and zinc stearate dispersion (30%) were prepared as shown in Table 1. A protective layer coating solution is prepared by mixing and stirring, coated and dried on the thermosensitive coloring layer coated paper so as to have a dry weight of 2 g / m ^2, and dried with a super calender at a pressure of 15 kg / cm ^2. By rendering, a thermosensitive recording material of the present invention and a comparative thermosensitive recording material were prepared.

[0039]

[Table 1]

Examples 6 to 8, Comparative Examples 5 and 6 Next, in the same manner as in Example 2, a protective layer was coated on the thermosensitive coloring layer coated paper so as to have a dry weight of 2 g / m ² and dried. The calendering pressure was set as shown in Table 2 with a super calender to prepare a thermosensitive recording material of the present invention and a comparative thermosensitive recording material.

[0041]

[Table 2]

Examples 9 to 11 Next, the polyvinyl alcohol 10 in the protective layer of Example 2 was used.
% Of an aqueous solution of an isobutylene-maleic anhydride copolymer in the same manner as in Example 2, except that the thermal recording material of the present invention was prepared.

[0043]

[Table 3]

Examples 12 to 14 and Comparative Example 7 The present invention and comparative examples were prepared in the same manner as in Example 2 except that dialkyl succinate was used in the protective layer of Example 2 as shown in Table 4. Was prepared.

[0045]

[Table 4]

<Evaluation> Table 5 shows the results of the evaluation by the following test methods using the heat-sensitive recording material obtained above.

(1) Dynamic color development characteristics Using a thermal printing test apparatus having a thin-film head manufactured by Kyocera Corporation, head power 0.45 W / DOT, line recording time 4 / ms, scanning line density 8 × 7.7 DOT. The print density was measured with a Macbeth densitometer R-914 under the conditions of / mm and a pulse width of 0.6 ms.

(2) Dot Reproducibility The dot reproducibility of the image used in the dynamic color test was visually evaluated. ◎ Very good. ○ good △ normal × bad

(3) Sticking test Using a Xerox facsimile 7005, the facsimile chart No. 3 was received in the G3 standard mode, and the state of sticking was visually evaluated.

(4) Plasticity test Polycarbonate containing a plasticizer in the color-developed portion printed using a thermal gradient tester manufactured by Toyo Seiki Co., Ltd. under the conditions of 130 ° C., compression time of 1 s, and compression pressure of 2.0 MPa. The vinyl sheets were overlapped, a load of 0.1 Mpa was applied, and the concentration after storage at 40 ° C. for 15 hours was measured.

[0051]

[Table 5]

From the results shown in Table 5, it can be seen that the heat-sensitive recording material of the present invention is excellent in color developing property and dot reproducibility, and also excellent in head matching property and chemical resistance.

[0053]

The heat-sensitive recording material according to the present invention is characterized in that an intermediate layer containing non-embracing plastic hollow fine particles having an average particle diameter of 2 to 10 μm and a hollowness of 90% or more on a support, a leuco dye and In a thermosensitive coloring material in which a thermosensitive coloring layer containing a coloring agent as a main component and a protective layer containing a pigment and a resin as main components are sequentially laminated, aluminum hydroxide is used as a pigment in the protective layer.
It contains zinc stearate as a lubricant, and the weight ratio to the resin is 75 to 125% by weight of aluminum hydroxide.
Since zinc stearate is 5 to 15% by weight, it is excellent in coloring property and dot reproducibility, and excellent in head matching property and chemical resistance. The protective layer surface has a Bekk smoothness of 1,000 to 3,000 seconds, the protective layer contains, as a resin, a copolymer of isobutylene and maleic anhydride in an amount of 30% by weight or more, and dialkyl succinate succinate as a resin. By adding 1 to 5%, the effect is further improved.

Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location B41M 5/18 101C 101D

Claims (4)

[Claims] An average particle size of 2 to 10 μm on a support.
m, an intermediate layer containing non-foamable plastic hollow particles having a hollowness of 90% or more, a thermosensitive coloring layer mainly containing leuco dye and a developer, and a protective layer mainly containing pigment and resin are sequentially laminated. In the heat-sensitive recording material, the protective layer contains aluminum hydroxide as a pigment and zinc stearate as a lubricant, and the weight ratio to the resin is 75 to 125% by weight of aluminum hydroxide and 5 to 15% by weight of zinc stearate. A heat-sensitive recording material, characterized in that the content is by weight. 2. The Beck smoothness of the surface of the protective layer is 100.
2. The heat-sensitive recording material according to claim 1, wherein the time is from 0 to 3000 seconds. 3. The heat-sensitive recording material according to claim 1, wherein the protective layer contains a copolymer of isobutylene and maleic anhydride as a resin in an amount of 30% by weight or more. 4. The heat-sensitive recording material according to claim 1, wherein the protective layer contains 1 to 5% of dialkyl succinate relative to the resin.