JPH1158958A - Heat sensitive recording body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sensitive recording body excellent in transparency, printability and water resistance. SOLUTION: In a heat sensitive recording body, in which a heat sensitive recording layer, a protective layer is provided in the order named on a transparent support, the heat sensitive recording layer consists at least of two different layers or a coloring agent-containing later and a basic dye-containing layer under the condition that at least one layer between them is one provided by a vapor deposition method and, the protective layer includes a film-forming acrylic resin. In this case, the protective layer includes acrylic resin particles having an average particle diameter of 1.0 μm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material utilizing a color-forming reaction between a colorless or light-colored basic dye and a color former, and more particularly to a heat-sensitive recording material excellent in transparency, printability and water resistance. Is about

[0002]

2. Description of the Related Art A thermosensitive recording medium which uses a color reaction between a colorless or light-colored basic dye and an organic or inorganic colorant to contact both coloring materials by heat to obtain a recorded image is often used. Are known. Such a thermosensitive recording medium is relatively inexpensive, and its recording equipment is compact and easy to maintain, so that it is used not only as a recording medium for facsimile machines and various computers but also in a wide range of fields.

[0003] With the expansion of applications, not only paper supports but also many films and synthetic papers have been produced.
As one of them, there is a highly transparent thermosensitive recording film using a transparent film as a support for medical use, OHP use or drawing. In order to increase the transparency of the heat-sensitive recording film, there is a method in which the particulate material added to the recording layer, the protective layer, or the like is made into fine particles, or the ratio of the adhesive is increased, but the transparency is not sufficient. There is no present.

Japanese Patent Application Laid-Open No. 59-106992 discloses a technique of laminating a color former layer and a color former layer by vacuum deposition, but the transparency, storage stability and printability are not sufficient. Japanese Patent Application Laid-Open No. Hei 4-239688 discloses a method of applying a dye and a color former in a combination of a solvent system and an aqueous system, but has disadvantages such as insufficient transparency and poor sensitivity. Was.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material having excellent transparency, printability and water resistance.

[0006]

According to the present invention, there is provided a heat-sensitive recording medium having a heat-sensitive recording layer and a protective layer provided on a transparent support, wherein the heat-sensitive recording layer comprises at least a layer containing a colorant and a basic dye. A thermosensitive recording medium comprising two types of layers including at least one layer provided by a vapor deposition method, and a protective layer containing a film-forming acrylic resin. .

Further, by providing at least one of the heat-sensitive recording layers by a solvent coating method, a more excellent heat-sensitive recording medium can be obtained. Further, by including an acrylic resin particle having an average particle diameter of 1.0 μm or less in the protective layer, a more excellent thermosensitive recording medium can be obtained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a vapor deposition method used in the present invention, vacuum deposition by resistance heating, induction heating, electron beam heating or the like can be adopted. In addition, it is possible to control the crystallinity of the deposited film and improve the film strength by plasma combined deposition, in which a layer containing a colorant or a layer containing a basic dye and other materials constituting the heat-sensitive layer are deposited under the state of plasma generation. It is. As a condition of the vapor deposition method, it is preferable to perform the vapor deposition under a vacuum higher than 1 × 10 ⁻² Torr when plasma is not used, and under a vacuum higher than 1 Torr when plasma is used.

There are various methods for generating plasma.
A DC plasma method, a high-frequency plasma method, a microwave plasma method, and the like can be given. In particular, the high frequency plasma method is preferable from the viewpoint of easy handling, and the introduced gas is, for example, an inert gas such as helium or argon, N ₂ , O ₂ , or H ₂ .
₂ , CO ₂ and a mixed gas, air and the like. The gas flow rate and the amount of applied energy are not particularly limited as long as plasma is generated, but the balance between crystallinity, film strength, degree of discoloration of the deposited film, and recording density is best. It is preferable to adjust as follows.

In the present invention, as a method for forming the heat-sensitive recording layer, there is a solvent coating method using an organic solvent in addition to the vapor deposition method. Examples of the organic solvent for dissolving the material and the adhesive constituting the heat-sensitive layer include hydrocarbons. , Halogenated hydrocarbons, alcohols, ethers, acetals, ketones, esters and the like are used alone or as a mixed organic solvent.

Specific examples of the hydrocarbons include, for example, benzene, toluene, xylene, hexane, cyclohexane, methylcyclohexane, cyclopentane, petroleum ether, and naphthalene. Specific examples of the halogenated hydrocarbons include, for example, chloroform. , Methylene chloride, carbon tetrachloride, chlorobenzene, dichlorobenzene, and the like; specific examples of alcohols include, for example, methanol, ethanol, propanol, isopropanol, and butanol; and specific examples of ethers include, for example, ethyl ether and isopropyl ether. As specific examples of acetal, for example, diethyl acetal and the like, specific examples of ketones, for example, acetone, methyl ethyl ketone,
Specific examples of esters such as diethyl ketone include, for example, ethyl acetate, methyl acetate, methyl propionate, and the like, but are not limited thereto.

The adhesive used in the solvent coating is not particularly limited as long as it is a resin soluble in an organic solvent. However, a thermoplastic resin is particularly preferably used, and the adhesive used in the organic solvent as described above can be used. A soluble thermoplastic resin is more preferably used. Specific examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylic acid, and (meth) acrylamide. (Meth) acrylic acid monomer, (meth) acrylic acid ester, (meth) acrylamide, (meth) acrylic monomer such as (meth) acrylonitrile, itaconic acid, vinyl chloride, vinylidene chloride, vinyl acetate, styrene, ethylene, Necessary by copolymerizing monomers having copolymerizable ethylenically unsaturated bonds such as propylene and butadiene Acrylic resins, polystyrenes, poly-α-methylstyrenes, vinyl chloride / vinyl acetate copolymers, ethylene / vinyl acetate copolymers, polyvinyl acetal resins, etc., obtained by subjecting them to modification treatments such as hydrolysis, acetalization, etc. Cellulose polymers such as cellulose, polyester resins, polyurethane resins,
Examples include a coumarone-based resin and a nylon-based resin, but are not limited to these, and two or more resins can be used in combination.

The amount of the adhesive to be used is not particularly limited, but may be 0.1 to the total solids of the coating solution.
It is desirable to adjust it in the range of 5 to 90% by weight, preferably 1 to 60% by weight. As the colorless or light-colored basic dye used in the present invention, various known dyes can be used, and specific examples thereof include, for example, 3,3-bis (p-dimethylaminophenyl) -6-dimethyl Aminophthalide, 3- (4-diethylamino-2-methylphenyl) -3- (4-dimethylaminophenyl) -6
Blue coloring dyes such as dimethylaminophthalide and 3-diethylamino-7-dibenzylamino-benzo [a] fluoran: 3- (N-ethyl-Np-tolyl) amino-7
-N-methylanilinofluoran, 3-diethylamino-7-anilinofluoran, 3-diethylamino-7-
Green coloring dyes such as dibenzylaminofluorane: 3,6
-Bis (diethylamino) fluoran-γ-anilinolactam, 3-cyclohexylamino-6-chlorofluoran, 3-dibutylamino-6-methyl-7-bromofluoran, 3-diethylamino-7-methylfluoran, 3 -Diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-7-chlorofluorane,
Rhodamine (o-chloroanilino) lactam, rhodamine (p-chloroanilino) lactam, 3-diethylamino-7,8-benzofluoran, 3- (N-ethyl-p
-Toluidino) -7-methylfluoran, 3-diethylamino-6,8-dimethylfluoran, 3- (N-ethyl-N-isoamyl) amino-benzo [a] fluoran, 3,3'-bis (1- Red-coloring dyes such as n-butyl-2-methylindol-3-yl) phthalide and 2- (4-dodecyloxy-3-methoxystyryl) quinoline: 3- (N-ethyl-N-isoamyl) amino-6 −
Methyl-7-anilinofluoran, 3- (N-methyl-
N-cyclohexyl) amino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-
Anilinofluoran, 3-di (n-butyl) amino-6
-Methyl-7-anilinofluoran, 3-di (n-pentyl) amino-6-methyl-7-anilinofluoran,
3-diethylamino-7- (o-chlorophenylamino) fluoran, 3-di (n-butyl) amino-7-
(O-chlorophenylamino) fluoran, 3-diethylamino-7- (o-fluorophenylamino) fluoran, 3-di (n-butyl) amino-7- (o-fluorophenylamino) fluoran, 3- (N-ethyl -P
-Toluidino) -6-methyl-7-anilinofluoran, 3- (N-ethyl-p-toluidino) -6-methyl-7- (p-toluidino) fluoran, 3- (N-ethyl-N-tetrahydro Furfurylamino) -6-methyl-7-anilinofluoran, 3-diethylamino-6
Chloro-7-anilinofluoran, 3- (N-methyl-
Nn-propylamino) -6-methyl-7-anilinofluoran, 3-dimethylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-
7-m-toluidinofluoran, 3- (Nn-hexyl-N-ethyl) amino-6-methyl-7-anilinofluoran, 3- (N-ethyl-N-isobutyl) amino-6 -Methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-p-ethoxyanilinofluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 3-piperidino-6-methyl -7-anilinofluoran, 2,2-bis {4- [6 '-(N-cyclohexyl-N-methylamino) -3'-methylspiro [phthalide-3,9'-xanthen-2'-yl- amino〕
Phenyl @ propane, 3-diethylamino-7- (3 '
Black-coloring dyes such as -trifluoromethylphenyl) aminofluorane: 3,3-bis [1- (4-methoxyphenyl) -1- (4-dimethylaminophenyl) ethylene-2-yl] -4,5 , 6,7-Tetrachlorophthalide, 3,3-bis [1- (4-methoxyphenyl) -1
-(4-pyrrolidinophenyl) ethylene-2-yl]-
4,5,6,7-tetrachlorophthalide, 3,3-bis [1,1-bis (4-pyrrolidinophenyl) ethylene-
2-yl] -4,5,6,7-tetrabromophthalide,
3-p- (p-dimethylaminoanilino) anilino-6
-Methyl-7-chlorofluorane, 3-p- (p-chloroanilino) anilino-6-methyl-7-chlorofluoran, 2,4-dimethyl-6 '-{[4- (N, N-dimethylamino ) Phenyl] amino} -spiro [isobenzofuran-1 (3H), 9 ′-[9H] xanthen]-
Dyes having an absorption wavelength in the near infrared region, such as 3-one and 3,6-bis (dimethylamino) fluorene-9-spiro-3 ′-(6′-dimethylamino) phthalide, are exemplified. Of course, the present invention is not limited to these, and two or more of them can be used in combination as needed.

The coloring agent used in the present invention is, for example, 4,
4'-isopropylidene diphenol, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-
Bis (4-hydroxyphenyl) -4-methylpentane, 4,4'-dihydroxydiphenylsulfide, hydroquinone monobenzyl ether, benzyl 4-hydroxybenzoate, 4,4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenyl Sulfone, 4
-Hydroxy-4'-isopropoxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxyphenyl-4'-benzyloxyphenylsulfone, 3, 4-dihydroxyphenyl-4 '
-Methylphenylsulfone, bis (4-hydroxyphenylthioethoxy) methane, 1,5-di (4-hydroxyphenylthio) -3-oxapentane, bis (p-hydroxyphenyl) butyl acetate, bis (p-hydroxyphenyl) ) Methyl acetate, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,4-bis [α-
Methyl-α- (4′-hydroxyphenyl) ethyl] benzene, 1,3-bis [α-methyl-α- (4′-hydroxyphenyl) ethyl] benzene, di (4-hydroxy-3-methylphenyl) sulfide , 2,2'-thiobis (3-tert-octylphenol), 2,2 '
Phenolic compounds such as -thiobis (4-tert-octylphenol): thiourea compounds such as N, N'-di-m-chlorophenylthiourea: p-chlorobenzoic acid, 4- [2- (p-methoxyphenoxy) ethyloxy ] Salicylic acid, 4- [3- (p-tolylsulfonyl)
Aromatic carboxylic acids such as propyloxy] salicylic acid and 5- [p- (2-p-methoxyphenoxyethoxy) cumyl] salicylic acid, and zinc, magnesium, aluminum, calcium, titanium, manganese and tin of these aromatic carboxylic acids; A salt with a polyvalent metal such as nickel, an antipyrine complex of zinc thiocyanate, a composite zinc salt of terephthalaldehyde acid and another aromatic carboxylic acid, etc .: arylsulfonylaminocarbonyl represented by the following general formula (1) Examples include compounds having an amino group.

[0015]

Embedded image

(However, R ₁ represents an unsubstituted or an aromatic group substituted by at least one member selected from a lower alkyl group, a lower alkoxy group and a halogen atom.) It is represented by the general formula (1). Compounds such as (1)
N- (p-toluenesulfonyl)-having one arylsulfonylaminocarbonylamino group
N'-phenylurea, N- (p-toluenesulfonyl)
-N '-(p-methoxyphenyl) urea, N- (p-toluenesulfonyl) -N'-(o-tolyl) urea, N-
(P-toluenesulfonyl) -N '-(m-tolyl) urea, N- (p-toluenesulfonyl) -N'-(p-tolyl) urea, N- (p-toluenesulfonyl) -N'-
(P-ethylphenyl) urea, N- (p-toluenesulfonyl) -N ′-(pn-propylphenyl) urea,
N- (p-toluenesulfonyl) -N '-(pn-butylphenyl) urea, N- (p-toluenesulfonyl)
-N ', N'-diphenylurea, N- (p-toluenesulfonyl) -N'-(p-hydroxyphenyl) urea,
N- (p-toluenesulfonyl) -N '-(o-chlorophenyl) urea, N- (p-toluenesulfonyl)-
N '-(m-chlorophenyl) urea, N- (p-toluenesulfonyl) -N'-(2,4-dichlorophenyl)
Urea, N- (p-toluenesulfonyl) -N'-methyl-N'-phenylurea, N- (p-toluenesulfonyl) -N'-benzylurea, N- (p-toluenesulfonyl) -N '-( 1-naphthyl) urea, N- (p-toluenesulfonyl) -N '-(1- (2-methylnaphthyl)) urea, N- (benzenesulfonyl) -N'-phenylurea, N- (p-chlorobenzenesulfonyl) )-
N'-phenylurea, N- (o-toluenesulfonyl)
-N'-phenylurea, N- (p-toluenesulfonyl) -N'-methylurea, N- (p-toluenesulfonyl) -N'-ethylurea, N- (p-toluenesulfonyl) -N '-( 2-phenoxyethyl) urea, N, N '
-Bis (p-toluenesulfonyl) urea, N- (p-toluenesulfonyl) -N '-(o-diphenyl) urea,
N- (p-toluenesulfonyl) -N '-(p-ethoxycarbonylphenyl) urea, N- (p-toluenesulfonyl) -N'-butylurea, N- (p-chlorobenzenesulfonyl) -N'-propylurea , N- (p-methoxybenzenesulfonyl) -N'-phenylurea and the like:
(2) Bis (p-toluenesulfonylaminocarbonylamino) ketone, 1,2-bis (p-toluenesulfonylaminocarbonylamino) ethane, 1,1,6 as those having two or more arylsulfonylaminocarbonylamino groups , 6-Tetra (p-toluenesulfonylaminocarbonylamino) heptane, 1,5-bis (p-toluenesulfonylaminocarbonylamino)-
3-oxapentane, 1,5-bis (p-toluenesulfonylaminocarbonylamino) -3-thiopentane,
1,3-bis (p-toluenesulfonylaminocarbonylamino) -2-propanone, 1,5-bis (p-toluenesulfonylaminocarbonylamino) -3-
(2 ′-(p-toluenesulfonylaminocarbonylamino) ethyl) -3-azapentane, 1,3-bis (p
-Toluenesulfonylaminocarbonylaminomethyl)
Benzene, 1,4-bis (p-toluenesulfonylaminocarbonylaminomethyl) benzene, 4,4′-bis (p-toluenesulfonylaminocarbonylamino) diphenylmethane, 4,4′-bis (o-toluenesulfonylaminocarbonylamino) ) Diphenylmethane, 4,
4′-bis (benzenesulfonylaminocarbonylamino) diphenylmethane, 4,4′-bis (1-naphthalenesulfonylamylcarbonylamino) diphenylmethane, 2,2-bis (4 ′, 4 ″-(p-toluenesulfonylaminocarbonyl) Amino) phenyl) propane,
1,2-bis (4 ′-(p-toluenesulfonylaminocarbonylamino) phenyloxy) ethane, 2,5-
Bis (p-toluenesulfonylaminocarbonylaminomethyl) furan, 1,3-bis (p-toluenesulfonylaminocarbonylamino) benzene, 1,4-bis (p-toluenesulfonylaminocarbonylamino) benzene, 1,5-bis (P-toluenesulfonylaminocarbonylamino) naphthalene, 1,8-bis (p-toluenesulfonylaminocarbonylamino) naphthalene, 4,4′-bis (p-toluenesulfonylaminocarbonylamino) diphenyl ether, 3,3′-bis (P-toluenesulfonylaminocarbonylamino) diphenyl sulfone, 2,4-bis (p-toluenesulfonylaminocarbonylamino) toluene, 2,6-bis (p-toluenesulfonylaminocarbonylamino) toluene, 4,4′-bis p- toluenesulfonyl aminocarbonylamino) sulfide, and 3,4 '- bis (p- toluenesulfonyl aminocarbonylamino) diphenyl ether.

These colorants may be used alone or as a mixture of two or more. In addition,
Pigments, cross-linking agents, sensitizers, and storability improvers exemplified below to improve the physical properties, color development characteristics, and storability of the coating film in the solvent coating layer composed of the material used for the heat-sensitive layer and the adhesive And an ultraviolet absorber. When the material used for the heat-sensitive layer is deposited by a vapor deposition method, a sensitizer, a preservability improver, an ultraviolet absorber, etc. may be evaporated from the same evaporation source, or may be co-evaporated from different evaporation sources at the same time. It is possible.

In the case of using a solvent coating method for forming the heat-sensitive layer, a layer composed of a heat-sensitive material and an adhesive dissolved in an organic solvent must be provided immediately above the support. A multi-layer of a heat-sensitive material may be provided by a vapor deposition method, and furthermore, a layer of a sensitizer, a storage stability improving agent, an ultraviolet absorber or the like may be provided by a multi-layer method. When all layers are formed by a vapor deposition method, the order of layer formation does not need to be particularly limited, and a colorant, a basic dye is an essential component, and a sensitizer, a preservability improver, an ultraviolet absorber, etc. Any number of layers can be stacked.

Examples of the pigment include inorganic pigments such as kaolin, clay, calcium carbonate, aluminum hydroxide, aluminum oxide, calcined clay, calcined kaolin, titanium oxide, talc, zinc oxide, silica, and styrene microballs.
Organic pigments such as nylon powder, polyethylene powder, urea formalin resin filler, raw starch particles, silicon powder and the like.

Examples of the crosslinking agent include dialdehyde compounds such as glyoxal and dialdehyde starch, polyamine compounds such as polyethyleneimine, epoxy compounds,
Use of polyamide resins, melamine resins, diglycidyl compounds such as glycerin diglycidyl ether, dimethylol urea compounds, aziridine compounds, isocyanate compounds, and inorganic compounds such as ammonium persulfate, ferric chloride, magnesium chloride, and zirconium carbonate compounds. Can be.

Specific examples of the sensitizer include, for example, stearic acid amide, methoxycarbonyl-N-stearic acid benzamide, N-benzoylstearic acid amide, N-
Eicosanoic acid amide, ethylenebisstearic acid amide, behenic acid amide, methylenebisstearic acid amide, N-methylolstearic acid amide, dibenzyl terephthalate, dimethyl terephthalate, dioctyl terephthalate, benzyl p-benzyloxybenzoate, 1-hydroxy Phenyl-2-naphthoate, 2-naphthylbenzyl ether, m-terphenyl, dibenzyl oxalate, di-p-methylbenzyl oxalate, di-p-chlorobenzyl oxalate, p-benzylbiphenyl, p-
Tolylbiphenyl ether, di (p-methoxyphenoxyethyl) ether, 1,2-di (3-methylphenoxy) ethane, 1,2-di (4-methylphenoxy) ethane, 1,2-di (4-methoxyphenoxy) ) Ethane,
1,2-di (4-chlorophenoxy) ethane, 1,2-
Diphenoxyethane, 1- (4-methoxyphenoxy)
-2- (3-methylphenoxy) ethane, p-methylthiophenylbenzyl ether, 1,4-di (phenylthio) butane, p-acetotoluidide, p-acetophenethidide, N-acetoacetyl-p-toluidine, di ( β
-Biphenylethoxy) benzene, p-di (vinyloxyethoxy) benzene, 1-isopropylphenyl-2
-Phenylethane and the like.

As the preservability improver, for example, 2,2'-
Methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-
tert-butylphenol), 2,2′-ethylidenebis (4,6-di-tert-butylphenol),
4,4'-thiobis (2-methyl-6-tert-butylphenol), 4,4'-butylidenebis (6-te
rt-butyl-m-cresol), 1- [α-methyl-
α- (4′-hydroxyphenyl) ethyl] -4-
[Α ', α'-bis (4 "-hydroxyphenyl) ethyl] benzene, 1,1,3-tris (2-methyl-4-
(Hydroxy-5-cyclohexylphenyl) butane,
1,1,3-tris (2-methyl-4-hydroxy-5
-Tert-butylphenyl) butane, 4,4'-thiobis (3-methylphenol), 4,4'-dihydroxy-3,3 ', 5,5'-tetrabromodiphenylsulfone, 4,4'-dihydroxy- 3,3 ', 5,5'-
Tetramethyldiphenyl sulfone, 2,2-bis (4-
(Hydroxy-3,5-dibromophenyl) propane,
2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3,
Phenol compounds such as 5-dimethylphenyl) propane, 1,4-diglycidyloxybenzene, 4,4′-
Epoxy compounds such as diglycidyloxydiphenylsulfone, 4-benzyloxy-4 ′-(2-methylglycidyloxy) diphenylsulfone, diglycidyl terephthalate, cresol novolak epoxy resin, phenol novolak epoxy resin, and bisphenol A epoxy resin; N, N'-di-2-naphthyl-p-phenylenediamine, 2,2'-methylenebis (4,6-di-
and sodium or polyvalent metal salts of tert-butylphenyl) phosphate, bis (4-ethyleneiminocarbonylaminophenyl) methane and the like. Of course, the present invention is not limited to these, and two or more of them can be used as needed.

Examples of the ultraviolet absorber include salicylic acid-based ultraviolet absorbers such as phenyl salicylate, p-tert-butylphenyl salicylate and p-octylphenyl salicylate: 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2
-Hydroxy-4-octyloxybenzophenone,
Benzophenone-based ultraviolet absorbers such as 2,2'-dihydroxy-4-methoxybenzophenone: 2- (2'-hydroxy-5'-methylphenyl) benzotriazole;
2- (2'-hydroxy-3 ', 5'-di-tert-
Butylphenyl) -5-chlorobenzotriazole,
2,2-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazole-2
-Yl) phenol], 2- (2'-hydroxy-5 '
-Tert-butylphenyl) benzotriazole, 2
-(2'-hydroxy-3'-tert-butyl-5 '
-Methylphenyl) -5-chlorobenzotriazole,
2- [2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″,
6 "-tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2- (2'-hydroxy-5'-tert-octylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5' -Ji-
tert-butylphenyl) benzotriazole, 2-
4-di-tert-butylphenyl-3,5-di-te
rt-butyl-4-hydroxybenzoate, 2-
[2′-hydroxy-3 ′, 5′-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3'-dodecyl-5 '
-Methylphenyl) benzotriazole, 2- [2'-
Hydroxy-4 ′-(2 ″ -ethylhexyl) oxyphenyl] benzotriazole, 5-tert-butyl-
Octyl 3- (5-chloro-2H-benzotriazol-2-yl) -4-hydroxybenzene-propionate, methyl-3- [3-tert-butyl-5- (2H
-Benzotriazol-2-yl) -4-hydroxyphenol] propionate-condensate with polyethylene glycol (molecular weight about 300), 2- (2'-hydroxy-
3 ', 5'-sec-amylphenyl) benzotriazole-based UV absorbers such as benzotriazole: 2-ethylhexyl-2-cyano-3,3'-diphenylacrylate, ethyl-2-cyano-3,3'-diphenyl And cyanoacrylate-based ultraviolet absorbers such as acrylate. Above all, a benzotriazole-based ultraviolet absorber having a strong absorption up to a relatively long wavelength ultraviolet region is preferably used. Of course, the present invention is not limited to these, and two or more of them can be used as needed.

The protective layer provided on the heat-sensitive recording medium of the present invention uses an acrylic resin as a resin which is a main component of the film formation, and contains a pigment, a crosslinking agent, a lubricant and the like as required. is there. Examples of the acrylic resin include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylic acid,
(Meth) acrylamide and other (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylamide, (meth) acrylonitrile and other acrylic monomers, and itaconic acid and maleic copolymerizable with these acrylic monomers Acid, vinyl chloride, vinylidene chloride, vinyl acetate, styrene, ethylene, propylene, butadiene and other monomers having an ethylenically unsaturated bond are copolymerized, and if necessary, subjected to a modification treatment such as hydrolysis, acetalization, etc. It is obtained.

The amount of the resin as the main component is as follows.
It is preferable to adjust the total solid content of the protective layer in the range of 20 to 98% by weight. In the protective layer, other resins, pigments, cross-linking agents, lubricants and the like can be contained, if necessary, in addition to the resin of the main component.

Specific examples of the resin that can be contained in the protective layer include, for example, starches such as oxidized starch, enzyme-modified starch, cation-modified starch, esterified starch, etherified starch, methylcellulose, carboxymethylcellulose, and methoxycellulose. , Cellulose resins such as hydroxyethyl cellulose, completely (or incomplete) saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, acetoacetylated polyvinyl alcohol, polyvinyl alcohols such as silicon-modified polyvinyl alcohol, acrylic resins other than the main component,
Polyvinyl pyrrolidone, styrene / maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, casein, polyvinyl acetate, polyurethane, styrene / butadiene copolymer, vinyl chloride / vinyl acetate copolymer, ethylene -Vinyl acetate copolymer, styrene-butadiene-acrylic copolymer, and the like.

The pigments to be used include inorganic pigments such as kaolin, clay, calcium carbonate, aluminum hydroxide, aluminum oxide, calcined clay, calcined kaolin, titanium oxide, talc, zinc oxide, silica, styrene microballs, nylon powder and the like. , Polyethylene powder,
Organic pigments such as urea / formalin resin filler, raw starch particles, silicone powder, and the like.

Crosslinking agents for improving the durability of the protective layer include dialdehyde compounds such as glyoxal and dialdehyde starch; polyamine compounds such as polyethyleneimine; epoxy compounds; polyamide resins; melamine resins; Diglycidyl compounds such as glycidyl ether, dimethylol urea compounds, aziridine compounds, blocked isocyanate compounds, and inorganic compounds such as ammonium persulfate, ferric chloride, and magnesium chloride may be used in the range of 0 to 20%. it can. Examples of the lubricant to be used include waxes such as zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax, and ester wax; alkyl phosphates such as lauryl phosphate, oleyl phosphate, and stearyl phosphate; Its alkali metal salts, glyceryl monomyristate, glyceryl monostearate,
Glycerin fatty acid esters such as glyceryl monooleate, glyceryl distearate, and glyceryl dioleate; polyglycerols such as diglyceryl monolaurate, diglyceryl dilaurate, tetraglyceryl monolaurate, hexaglyceryl monolaurate, and decaglyceryl monolaurate There are fatty acid esters, silicone oils and the like, and among them, it is necessary to select one having no desensitizing action, decoloring action, and ground coloring action. The coating liquid for the protective layer is prepared by mixing and stirring a resin, a pigment, a lubricant and the like using water or a mixed solvent of water and an organic solvent as a dispersion medium.
If necessary, auxiliary agents such as a dispersant, an antifoaming agent, a coloring dye, a fluorescent dye, a crosslinking agent, and an ultraviolet absorber can be added to the coating liquid.

The protective layer has an average particle diameter of 1 μm.
By adding a resin composition of m or less, better printability can be obtained. As the resin component of the resin composition having an average particle diameter of 1 μm or less, monomers that can be used for the acrylic resin component can be used, and in particular, monomers having two or more ethylenically unsaturated bonds, for example, ethylene glycol, diethylene glycol, Combined use of polyhydric alcohols such as propylene glycol, trimethylolpropane, and pentaerythritol with esters of (meth) acrylic acid, and polyfunctional monomers such as diallyl maleate and divinylbenzene increase the crosslink density and increase the temperature to 100 ° C. This is effective as a resin component that does not form a film.

The heat resistance of the protective layer is improved by mixing the acrylic resin as the main component and a resin composition having an average particle diameter of 1 μm or less by a method such as a blending method or a core-shell type copolymerization method. The printing suitability is improved. If the average particle size of the resin component not forming a film exceeds 1 μm, the transparency of the thermosensitive recording medium is adversely affected.
It is desirable that:

The method for forming the solvent-coated layer and the protective layer of the heat-sensitive recording layer is not particularly limited. For example, air knife coating, buriba blade coating, pure blade coating, rod blade coating, short dwell coating, curtain coating, die coating It is formed by an appropriate coating method such as coating and gravure coating.

The coating amount of the coating liquid for the protective layer is adjusted in the range of about 0.5 to 10 g / m ² in terms of dry weight. In addition,
The support has a thickness of 4 to 250 μm, preferably 20 to 250 μm.
A transparent plastic film of about 200 μm is appropriately selected and used. The plastic film is not particularly limited and is a cellulose derivative film such as a cellulose triacetate film, polyethylene terephthalate, polybutylene terephthalate, a polyester film such as polyethylene naphthalate, a polyethylene film, a polyolefin film such as polypropylene, a polyvinyl chloride film, Polycarbonate film, polyamide film, polysulfone film, polyethersulfone film, polyetheretherketone film, polyetherimide film, polyphenylenesulfide film, polyacrylate film, polyesterether film, polyamideimide film, fluororesin film, polyurethane film, Acrylic film, polyvinyl butyral film, Li styrene film, and including polyvinyl alcohol film or the like,
In addition, a synthetic resin-based transparent film can be used alone or bonded.

By providing a resin layer on the protective layer and / or on the back surface of the thermosensitive recording sheet as required, it is possible to further enhance the preservability of the thermosensitive recording image. In addition, various known techniques in the field of heat-sensitive recording material manufacturing can be applied by applying an adhesive to the back surface and processing it into an adhesive label, or providing a magnetic layer. Needless to say, super calendering can be performed after the formation of the heat-sensitive recording layer and the protective layer to improve image quality and image density.

By applying and curing a coating containing a resin which is cured by electron beam irradiation on the protective layer, the glossiness can be further increased, and the color density and the resistance can be further improved. It is possible to improve the print storability such as plasticizer properties and water resistance. Examples of the electron beam curable resin include (A) a radical polymerizable monofunctional monomer: acrylic acid, ethyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate,
Hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate, trioxyethyl acrylate, nonylphenoxyethyl acrylate, tetrahydrofurfuryloxyethyl acrylate, 1,3-dioxolane acrylate, phenoxydiethylene glycol acrylate, benzyl acrylate, butoxyethyl acrylate, cyclohexyl acrylate , Dicyclopentanyl acrylate,
Dicyclopentenyl acrylate, glycidyl acrylate, carbitol acrylate, isobornyl acrylate and the like. (B) radically polymerizable polyfunctional monomer: 1,
6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate,
Dicyclopentanyl diacrylate, butylene glycol diacrylate, pentaerythritol diacrylate, trimethylolpropane triacrylate, propylene oxide-modified trimethylolpropane triacrylate, pentaerythritol triacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hexaacrylate, caprolactone Modified dipentaerythritol hexaacrylate, tetramethylolmethanetetraacrylate, and the like. (C) Radical polymerizable oligomer (prepolymer): polyester (poly) acrylate, urethane (poly) acrylate, epoxy (poly) acrylate, polyol (poly) acrylate and the like.

The coating amount of the resin cured by the electron beam is not necessarily limited, but may be 0.1 g
/ M ² , the desired effect of the present invention cannot be expected, and 20
If the coating amount exceeds g / m ² , the recording density may be significantly reduced.
m ² , more preferably in the range of about 0.5 to 10 g / m ² .

In the electron beam-curable resin component, in addition to the above-mentioned prepolymers and monomers, if necessary, for example, pigments, defoaming agents, leveling agents, lubricants, surfactants, plasticizers and the like may be added. An agent can be appropriately added.

[0037]

The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted to such specific Examples. Parts and% in Examples are parts by weight and% by weight, respectively, unless otherwise specified.

Example 1 Preparation of Coating Solution for Protective Layer Acrylic resin emulsion having a solid content of 52% (trade name:
POLYSOL AM2250, manufactured by Showa Kobunshi Co., Ltd.) 19.2
Part, 10% aqueous solution of dioctyl sodium sulfosuccinate 3
Parts, 3 parts of zinc stearate dispersion having a solid content of 20%, 5%
A composition comprising 20 parts of a glyoxal aqueous solution was mixed and stirred to obtain a coating liquid for a protective layer. Preparation of Coloring Agent Coating Solution 9 parts of 4,4′-isopropylidene diphenol, polyvinyl butyral resin (trade name: Denka butyral # 3)
(000-K, manufactured by Denki Kagaku) was dissolved in 40 parts of ethanol and 45 parts of toluene to obtain a coating liquid. · Formation of thermosensitive recording layer polyester film (trade name: Lumirror T60, Toray Industries Inc., thickness 100 [mu] m) on, as the coating amount after drying of the above color developer coating solution is 5 g / m ² After coating and drying, a basic dye 3-di (n-butyl) amino-6-methyl-7-anilinofluoran (melting point: 180 ° C.) was vacuum-deposited thereon, and a basic dye film having a thickness of 1000 nm was formed. Was formed. · On the film forming the above basic dyes of the protective layer, after the coating dried to a coating weight after drying using the protective layer coating solution is 2 g / m ^2,
A thermosensitive recording medium was obtained.

Example 2 A heat-sensitive recording material was obtained in the same manner as in Example 1, except that the preparation of the colorant coating solution was changed as follows. Preparation of Coloring Agent Coating Solution 7.5 parts of 4,4′-isopropylidene diphenol, 1.5 parts of oxalic acid-di-p-chlorobenzyl ester, polyvinyl butyral resin (trade name: denkabutyral)
# 3000-K) Ethanol 4
0 parts and 45 parts of toluene to obtain a coating solution.

Example 3 In Example 1, N- (p-toluenesulfonyl)-was used in place of 4,4'-isopropylidenediphenol.
Using N'-phenylurea, 3-diethylamino-6-methyl-7-anilinofluoran was used instead of 3-di (n-butyl) amino-6-methyl-7-anilinofluoran. Except for the above, a thermosensitive recording medium was obtained in the same manner as in Example 1.

Example 4 In Example 3, oxalic acid-di-p-chlorobenzyl ester (melting point: 120 ° C.) was vacuum-deposited between the colorant coating layer and the film of the basic dye to give a film thickness of 500 nm. A heat-sensitive recording material was obtained in the same manner as in Example 1 except that a sensitizer film was formed.

Example 5 A thermosensitive recording medium was obtained in the same manner as in Example 4, except that the following coating liquid for a protective layer was used. -Preparation of protective layer coating liquid Acrylic resin emulsion with a solid content of 52% (trade name:
POLYSOL AM2250, manufactured by Showa Kobunshi Co., Ltd.) 19.2
Parts, acrylic polymer particles having a particle size of 1 to 2 μm (trade name: MP-1400, manufactured by Soken Chemical Co., Ltd.), 3 parts of a 10% aqueous solution of sodium dioctylsulfosuccinate, solid content 2
A composition comprising 3 parts of a 0% zinc stearate dispersion and 20 parts of a 5% glyoxal aqueous solution was mixed and stirred to obtain a coating liquid for a protective layer.

Example 6 A thermosensitive recording medium was obtained in the same manner as in Example 5, except that the following coating liquid for a protective layer was used. Preparation of protective layer coating liquid Acrylic emulsion type resin component capable of forming a film at 60 ° C. or lower and average particle diameter of not forming a film at 100 ° C. 1.0
A resin composition having a solid concentration of 20%, which is a mixture of an emulsion-type resin component having a particle size of μm or less (trade name: Acryset SC2
291, manufactured by Nippon Shokubai), a composition consisting of 50 parts of a 10% aqueous solution of sodium dioctylsulfosuccinate, 3 parts of a dispersion of zinc stearate having a solid content of 20% and 20 parts of a 5% aqueous glyoxal solution was mixed with stirring to protect A layer coating liquid was obtained.

Example 7 A thermosensitive recording medium was obtained in the same manner as in Example 6, except that the following coating liquid for a protective layer was used. Preparation of coating liquid for protective layer A core-shell type emulsion having a solid concentration of 20% (acrylic) having a resin component of 1 μm or less that does not form a film at 100 ° C. as a core and a component forming a film at 60 ° C. or less as a shell. Set SA558: Nippon Shokubai) 50 parts, 3 parts of a 10% aqueous solution of sodium dioctylsulfosuccinate, 3 parts of a zinc stearate dispersion having a solid content of 20%, and 5% aqueous solution of glyoxal 2
0 parts of the composition was mixed and stirred to obtain a coating liquid for a protective layer.

Example 8 In Example 7, N- (p-toluenesulfonyl) -N'-phenylurea was used as a color former, and a layer of the color former was formed to a thickness of 2000 nm by vacuum deposition instead of solvent coating. A heat-sensitive recording material was obtained in the same manner as in Example 7 except for the above.

Example 9 A heat-sensitive recording material was obtained in the same manner as in Example 8, except that when forming the colorant layer, the layer was deposited under the occurrence of argon plasma.

Comparative Example 1 A heat-sensitive recording material was obtained in the same manner as in Example 1 except that the formation of the coating liquid for the protective layer was changed as follows. Preparation of coating liquid for protective layer 100 parts of a 10% aqueous solution of polyvinyl alcohol (trade name: PVA105, manufactured by Kuraray), 3 parts of a 10% aqueous solution of sodium dioctylsulfosuccinate, 3 parts of a zinc stearate dispersion having a solid content of 20% A composition comprising 20 parts of a 5% aqueous glyoxal solution was mixed and stirred to obtain a coating liquid for a protective layer.

Comparative Example 2 A thermosensitive recording medium was obtained in the same manner as in Example 1, except that the formation of the coating liquid for the protective layer was changed as follows. Preparation of coating liquid for protective layer 25 parts kaolin (trade name: UW-90, manufactured by EMC),
Acetoacetyl group-modified polyvinyl alcohol (trade name:
Gohsefimer Z-200, manufactured by Nippon Gohsei
A composition comprising 100 parts of a 0% aqueous solution, 3 parts of a 10% aqueous solution of dioctyl sodium sulfosuccinate, 3 parts of a zinc stearate dispersion having a solid content of 20%, 5 parts of a 5% aqueous glyoxal solution, and 100 parts of water is mixed and stirred. Thus, a coating liquid for a protective layer was obtained.

The following evaluation tests were performed on the 11 types of heat-sensitive recording materials thus obtained, and the results are shown in Table 1.

[Evaluation] [Recording density] Thermal printer (trade name: UP-860,
Recording was performed with a Sony (manufactured by Sony Corporation), and the density of the obtained recorded image was measured using a transmission densitometer (TD-904, manufactured by Macbeth).

[Printing Suitability] The degree of sticking when printing with the thermal printer was evaluated. ：: Clear printing without sticking was obtained. ×: Sticking occurred, and clear printing was not obtained. [Transparency of Thermal Recording Medium: Haze Value] The haze value of the thermal recording medium was measured using a haze meter (trade name: TC-H1V, manufactured by Tokyo Denshoku Co., Ltd.).

[Water Resistance] Water droplets were dropped on the surface of the thermosensitive recording medium, left for 5 minutes, and rubbed with a finger to observe the destruction state of the protective layer. Good: The surface does not peel off. Bad: Surface peeled off.

[0053]

[Table 1]

[0054]

As is clear from the results shown in Table 1, a heat-sensitive recording medium having good transparency, printability and water resistance was obtained by the constitution of the present invention.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B41M 5/18 E

Claims (3)

[Claims] 1. A heat-sensitive recording medium having a heat-sensitive recording layer and a protective layer sequentially provided on a transparent support, wherein the heat-sensitive recording layer comprises at least a layer containing a colorant and a layer containing a basic dye. A thermosensitive recording medium, wherein at least one of the layers is provided by a vapor deposition method, and the protective layer contains a film-forming acrylic resin. 2. The thermosensitive recording medium according to claim 1, wherein at least one of the thermosensitive recording layers is provided by a solvent coating method. 3. The heat-sensitive recording material according to claim 1, wherein the protective layer contains acrylic resin particles having an average particle diameter of 1.0 μm or less.