JP2009039874A - Heat-sensitive recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-sensitive recording material with a successful chemical resistance and stickiness. <P>SOLUTION: This heat-sensitive recording material includes: a heat-sensitive recording layer containing a normally colorless or pale-color dye precursor with electron donative properties and an electron-receptive compound which makes the dye precursor develop a color by thermal reaction, formed on the support; and a protecting layer containing an adhesive and a crosslinking agent formed on the heat-sensitive recording layer. The protecting layer includes an acetoacetyl-modified polyvinyl alcohol as an adhesive, and a silane coupling agent with an amino group as a crosslinking agent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat-sensitive recording material having good chemical resistance and sticking property.

  A heat-sensitive recording material generally has a heat-sensitive recording layer that is colored by heat on a support. By heating with a thermal head, a thermal pen, laser light, etc., the dye precursor and the developer are instantaneously formed. A recorded image can be obtained by reaction. Such a heat-sensitive recording material has advantages such as that recording can be obtained with a relatively simple device, easy maintenance, no noise generation, etc., measurement recorder, facsimile, printer, computer terminal, It is used in a wide range of fields such as label printing machines, boarding tickets, and ticket issuing machines.

  As the uses and demands of heat-sensitive recording materials are widely expanded, images are not lost even when they come into contact with various chemicals, that is, image storability is required. For example, water-based inks, oil-based inks, highlighters, vermilion, adhesives, office supplies such as diazo developers, cosmetics such as hand creams, hair tonics, and emulsions, or plasticizers contained in polyvinyl chloride films and synthetic leather Is required to be resistant to chemicals.

  In addition, the use of various barcodes by thermal recording and printing is increasing, and a thermal recording material having barcode printing suitability is demanded.

  As the amount of information contained in a barcode increases, there is an increasing demand for high-definition barcode printing. However, high-definition barcodes have the problem that the readability is greatly reduced due to barcode changes due to printing failures such as sticking, or slight changes in the width of spaces, or missing barcodes due to white spots in printing. ing. In addition, due to the recent downsizing and power saving of recording devices, there are increasing demands for improving the thermal response and device matching for thermal recording heads.

  That is, there is a demand for a heat-sensitive recording material that exhibits a color density similar to that in the past even with low applied energy due to high speed and low power consumption, and that is free from printing problems such as sticking.

  On the other hand, heat-sensitive recording materials used for terminals used outdoors such as for handy terminals and food label applications require water resistance so that the print surface does not peel off due to moisture. Has been.

  For the purpose of improving the chemical resistance of the heat-sensitive recording material, methods for forming a protective layer having various structures on the heat-sensitive recording layer (for example, see Patent Documents 1 to 3) have been proposed. In this method, the sticking property is insufficient.

In order to improve the sticking property of the heat-sensitive recording material having a protective layer, heat-sensitive recording materials having various structures have been proposed (see, for example, Patent Documents 4 to 7). It is difficult to achieve both compatibility and sticking properties.
JP 59-52693 A JP-A-4-34785 Japanese Patent Laid-Open No. 61-25884 JP-A-5-8543 JP-A-6-183150 JP-A-6-336083 Japanese Patent Laid-Open No. 7-179044

  An object of the present invention is to solve these problems and provide a heat-sensitive recording material having good chemical resistance and sticking property.

  As a result of intensive studies, the present inventors have invented the heat-sensitive recording material of the present invention that can solve the problems. That is,

  A heat-sensitive recording layer containing an electron-donating ordinary colorless or light-colored dye precursor on a support and an electron-accepting compound that reacts upon heating to develop the dye precursor, and an adhesive on the heat-sensitive recording layer And a protective layer containing a crosslinking agent, wherein the protective layer contains an acetoacetyl-modified polyvinyl alcohol as an adhesive and a silane coupling agent having an amino group as a crosslinking agent. It is.

  Further, the protective layer preferably contains a zirconium compound as a crosslinking agent.

  According to the present invention, a heat-sensitive recording material having good chemical resistance and sticking property can be obtained.

  The contents of the present invention will be described more specifically. The heat-sensitive recording material of the present invention has a heat-sensitive recording layer that is colored by heat on a support, and a protective layer having an adhesive and a crosslinking agent on the heat-sensitive recording layer.

  The protective layer constituting the heat-sensitive recording material of the present invention is composed of an adhesive, a crosslinking agent, an inorganic pigment, a lubricant and the like.

  The protective layer of the present invention contains acetoacetyl-modified polyvinyl alcohol as an adhesive and a silane coupling agent having an amino group as a crosslinking agent. By using a combination of acetoacetyl-modified polyvinyl alcohol and a silane coupling agent having an amino group, a heat-sensitive recording material having good chemical resistance and sticking property can be obtained.

  Examples of the silane coupling agent having an amino group used in the present invention include N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane and N- (2-aminoethyl) -3-aminopropyltrimethoxy. Examples thereof include silane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane.

  The protective layer of the present invention can contain a crosslinking agent other than the silane coupling agent having an amino group as long as the desired effect of the present invention is not impaired. Specifically, boron compounds such as glyoxal, boric acid and borax, metal compounds having a valence of 2 or more such as zirconium, titanium and aluminum, hydrazide compounds, amine compounds, epoxy compounds, N-methylol compounds, and aziridines Compounds and oxazoline compounds. Among these, a zirconium compound can further improve chemical resistance and sticking property.

  Examples of zirconium compounds include zirconium tetrachloride, zirconyl chloride, zirconyl hydroxychloride, zirconyl carbonate, zirconyl carbonate / ammonium carbonate, zirconyl carbonate / potassium nitrate, zirconyl sulfate, zirconyl sulfate, sodium zirconyl sulfate, acidic zirconyl sulfate trihydrate, Zirconyl acetate, zirconyl acetate / ammonium, zirconyl lactate, zirconyl stearate, zirconyl propionate, zirconyl phosphate, zirconyl phosphate / sodium, zirconyl silicide, zirconyl hexafluoride / potassium hexaalkanoamine, zirconium compound, aminocarboxylic acid A zirconium compound etc. are mentioned.

  Other adhesives can be used for the protective layer of the present invention as long as the desired effects of the present invention are not impaired. Specifically, fully saponified or partially saponified polyvinyl alcohol, diacetone modified polyvinyl alcohol, carboxy modified polyvinyl alcohol, silicon modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, styrene / maleic anhydride copolymer Obtained from water-soluble resins such as alkali salts of ethylene, alkali salts of ethylene / acrylic acid copolymers, alkali salts of styrene / acrylic acid copolymers, and latexes such as styrene / butadiene latex, acrylic latex and urethane latex And a hydrophobic resin.

  A pigment can be added to the protective layer of the present invention in accordance with purposes such as improving whiteness and preventing printing residue on the thermal head. For example, aluminum hydroxide, diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, magnesium hydroxide, titanium oxide, zinc oxide, silicon oxide, amorphous silica, amorphous calcium silicate, colloidal silica, Colloidal alumina, calcium sulfate, barium sulfate, titanium dioxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, calcium silicate, magnesium silicate, alumina, lithopone, zeolite, hydrohalloysite and other white inorganic pigments, vinyl chloride, vinylidene chloride, Organic resin with vinyl acetate, methyl acrylate, ethyl acrylate, methyl methacrylate, acrylonitrile, styrene and other monomers as the main component, or a copolymer resin with these monomers as the main component Hollow particles, penetrating The organic pigments and known pigments such as organic pigments having an opening mentioned has, it can be used singly or two or more kinds.

The protective layer of the present invention may contain higher fatty acid metal salts such as zinc stearate and calcium stearate, and waxes such as paraffin, oxidized paraffin, polyethylene, polyethylene oxide, and castor wax in order to improve sticking properties. . Other additives include pigment dispersants, thickeners, fluidity improvers, antifoaming agents, antifoaming agents, mold release agents, foaming agents, penetrating agents, colored dyes, colored pigments, fluorescent whitening agents, UV absorption An agent, an antioxidant, a preservative, a water-proofing agent and the like can be appropriately added. Ze'inuinurikoryou protective layer is preferably ^{0.2~10g / m 2, 0.5~5g / m} 2 is more preferable.

  The heat-sensitive recording layer constituting the heat-sensitive recording material of the present invention can be obtained by mixing each aqueous dispersion obtained by finely pulverizing each color forming component and a resin, and coating and drying on a support.

  For the heat-sensitive recording layer, diatomaceous earth, talc, kaolin, calcined kaolin, heavy calcium carbonate, precipitated calcium carbonate, magnesium carbonate, zinc oxide, aluminum oxide, aluminum hydroxide, magnesium hydroxide, titanium dioxide, barium sulfate are used as pigments. , Zinc sulfate, amorphous silica, amorphous calcium silicate, colloidal silica and other inorganic pigments, melamine resin filler, urea-formalin resin filler, polyethylene powder, nylon powder, styrene plastic pigment, acrylic plastic pigment, carbonized Organic pigments such as hydrogen-based plastic pigments can be used.

  A lubricant can be added to the heat-sensitive recording layer for the purpose of improving sticking or the like. As specific examples, those similar to the inorganic pigments shown in the description of the protective layer are preferably used.

For the purpose of improving light resistance, the heat-sensitive recording layer has a UV-absorbing agent such as benzophenone or benzotriazole, a surfactant containing a high molecular weight anionic or nonionic as a dispersing / wetting agent, and A fluorescent dye, an antifoaming agent, etc. are added as needed. The coating amount of the thermosensitive recording layer is usually preferably 0.05 to 2.0 g / m ^{2 in} terms of the absolute dry coating amount of the dye precursor in order to obtain sufficient thermal response. 0 g / m ² is more preferable.

  The electron-donating normally colorless or light-colored dye precursor contained in the heat-sensitive recording layer constituting the heat-sensitive recording material of the present invention is typically represented by pressure-sensitive recording materials or those used in heat-sensitive recording materials. However, it is not particularly limited.

As an example of a specific dye precursor,
(1) Triarylmethane compounds: 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (crystal violet lactone), 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- (P-dimethylaminophenyl) -3- (2-phenylindol-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)- -Dimethylaminophthalide, 3,3-bis (2-phenylindol-3-yl) -5-dimethylaminophthalide, 3- (p-dimethylaminophenyl) -3- (1-methylpyrrol-2-yl) ) -6-dimethylaminophthalide, etc.

  (2) Diphenylmethane compounds: 4,4′-bis (dimethylaminophenyl) benzhydrylbenzyl ether, N-chlorophenylleucooramine, N-2,4,5-trichlorophenylleucooramine, etc.

  (3) Xanthene compounds: Rhodamine B anilinolactam, rhodamine Bp-chloroanilinolactam, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-7-octylaminofluorane, 3-diethylamino- 7-phenylfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-chloro-7-methylfluorane, 3-diethylamino-7- (3,4-dichloroanilino) fluorane, 3-dibutyl Amino-7- (2-chloroanilino) fluorane, 3-diethylamino-7- (2-chloroanilino) fluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7- Anilinofluorane, 3-dipentylamino-6-methyl- -Anilinofluorane, 3- (N-ethyl-N-tolyl) amino-6-methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3- (N- Ethyl-N-tolyl) amino-6-methyl-7-phenethylfluorane, 3-diethylamino-7- (4-nitroanilino) fluorane, 3- (N-methyl-N-propyl) amino-6-methyl-7- Anilinofluorane, 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluorane, 3- (N-methyl-N-cyclohexyl) amino-6-methyl-7-anilino Fluorane, 3- (N-ethyl-N-tetrahydrofurfuryl) amino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7- (3-trifluorome Ruanirino) fluoran, etc.,

  (4) Thiazine compounds: benzoyl leucomethylene blue, p-nitrobenzoyl leucomethylene blue, etc.

  (5) Spiro compounds: 3-methylspirodinaphthopyrans, 3-ethylspirodinaphthopyrans, 3,3'-dichlorospirodinaphthopyrans, 3-benzylspirodinaphthopyrans, 3-methylnaphtholopyrans (3-methoxy) Benzo) spiropyran, 3-propyl spirobenzopyran and the like. These dye precursors can be used alone or in admixture of two or more as required.

  The electron-accepting compound contained in the heat-sensitive recording layer constituting the heat-sensitive recording material of the present invention is typically represented by a pressure-sensitive recording material or an acidic substance used in the heat-sensitive recording material, but is not limited thereto. There is nothing. For example, phenol derivatives, aromatic carboxylic acid derivatives, N, N′-diarylthiourea derivatives, arylsulfonylurea derivatives, polyvalent metal salts such as zinc salts of organic compounds, benzenesulfonamide derivatives, urea urethane compounds, etc. Can do.

  Specific examples of the electron-accepting compound contained in the heat-sensitive recording layer are listed below, but are not necessarily limited to these compounds.

  4-hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy-4'-n-propoxydiphenylsulfone, 4,4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, 4-hydroxydiphenylsulfone, 4 -Hydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-methoxydiphenylsulfone, 4-hydroxy-4'-ethoxydiphenylsulfone, 4-hydroxy-4'-n-butoxydiphenylsulfone, 4-hydroxy-4 '-Benzyloxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, bis (3,5-dibromo-4-hydroxyphenyl) sulfone, bis (3,5-dichloro-4-hydroxyphenyl) sulfone, 3,4-di Droxydiphenylsulfone, 3,4-dihydroxy-4'-methyldiphenylsulfone, 3,4,4'-trihydroxydiphenylsulfone, 3,4,3 ', 4'-tetrahydroxydiphenylsulfone, 2,3,4 -Trihydroxydiphenylsulfone, 3-phenylsulfonyl-4-hydroxydiphenylsulfone, 2,4-bis (phenylsulfonyl) phenol,

  4-phenylphenol, 4-hydroxyacetophenone, 1,1-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) pentane, 1,1-bis (4-hydroxyphenyl) hexane, , 1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) hexane, 1,1-bis (4-hydroxyphenyl)- 2-ethylhexane, 2,2-bis (3-chloro-4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,3-bis [1- (4- Hydroxyphenyl) -1-methylethyl] benzene, 1,3-bis [1- (3,4-dihydroxyphenyl) -1-methyl ester L] benzene, 1,4-bis [1- (4-hydroxyphenyl) -1-methylethyl] benzene, 4,4'-hydroxydiphenyl ether, 3,3'-dichloro-4,4'-dihydroxydiphenyl sulfide, Bis (2-hydroxynaphthyl) methane,

  2,2-bis (4-hydroxyphenyl) methyl acetate, 2,2-bis (4-hydroxyphenyl) butyl acetate, 4,4-thiobis (2-tert-butyl-5-methylphenol), 4-hydroxyphthal Dimethyl acid, benzyl 4-hydroxybenzoate, methyl 4-hydroxybenzoate, benzyl gallate, stearyl gallate, pentaerythritol tetra (4-hydroxybenzoic acid) ester, pentaerythritol tri (4-hydroxybenzoic acid) ester, 2 , 2-bis (hydroxymethyl) -1,3-propanediol polycondensate and 4-hydroxybenzoic acid dehydration condensate,

  N, N'-diphenylthiourea, 4,4'-bis [3- (4-methylphenylsulfonyl) ureido] diphenylmethane, N- (4-methylphenylsulfonyl) -N'-phenylurea, N- (benzenesulfonyl) ) -N '-[3- (4-toluenesulfonyloxyphenyl)] urea, N- (4-toluenesulfonyl) -N'-[3- (4-toluenesulfonyloxyphenyl)] urea,

  Salicylanilide, 5-chlorosalicylanilide, salicylic acid, 3,5-di-tert-butylsalicylic acid, 3,5-bis (α-methylbenzyl) salicylic acid, 4- [2 ′-(4-methoxyphenoxy) ethyloxy] salicylic acid , 3- (octyloxycarbonylamino) salicylic acid or metal salts (for example, zinc salts) of these salicylic acid derivatives,

  N- (4-hydroxyphenyl) -4-toluenesulfonamide, N- (2-hydroxyphenyl) -4-toluenesulfonamide, N-phenyl-4-hydroxybenzenesulfonamide and the like.

  The heat-sensitive recording layer constituting the heat-sensitive recording material of the present invention can contain a heat-fusible substance in order to improve its thermal response. In this case, those having a melting point of 60 to 180 ° C are preferable, and those having a melting point of 80 to 140 ° C are more preferably used.

  Specifically, stearic acid amide, N-hydroxymethyl stearic acid amide, N-stearyl stearic acid amide, ethylene bis stearic acid amide, methylene bis stearic acid amide, methylol stearic acid amide, N-stearyl urea, benzyl-2- Naphthyl ether, m-terphenyl, 4-benzylbiphenyl, 2,2′-bis (4-methoxyphenoxy) diethyl ether, α, α′-diphenoxyxylene, bis (4-methoxyphenyl) ether, diphenyl adipate, Dibenzyl oxalate, di (4-methylbenzyl ester) oxalate, bis (4-chlorobenzyl) oxalate, dimethyl terephthalate, dibenzyl terephthalate, phenyl benzenesulfonate, bis (4-allyloxyphenyl) sulfone, 1,2 -Known thermofusible substances such as bis (3-methylphenoxy) ethane, 1,2-diphenoxyethane, 4-acetylacetophenone, acetoacetate anilides and fatty acid anilides are used, but higher fatty acid amides are used. In some cases, it is more preferable because it functions as a lubricant.

  These compounds can be used alone or in combination of two or more. Further, in order to obtain sufficient thermal responsiveness, it is preferable that the heat fusible substance occupies 5 to 50% by mass in the total solid content of the thermosensitive recording layer.

  As the adhesive used for the heat-sensitive recording layer, various resins used in ordinary coating can be used as in the case of the protective layer. As a specific example, the same resin as that shown in the description of the protective layer is preferably used.

  As the support used in the heat-sensitive recording material in the present invention, paper is mainly used. In addition to paper, various woven fabrics, nonwoven fabrics, synthetic resin films, synthetic resin laminated papers, synthetic papers, metal foils, vapor deposition sheets, Or the composite sheet which combined these by bonding etc. can be used arbitrarily according to the objective.

In the heat-sensitive recording material of the present invention, if necessary, one or more undercoat layers composed of a single layer or a plurality of layers of pigment, resin, or the like can be provided between the support and the heat-sensitive recording layer. When the heat-sensitive recording material of the present invention is provided with a subbing layer, Ze'inuinurikoryou the undercoat layer is preferably ^{1~30g / m 2, 3~20g / m} 2 is more preferable.

  As the pigment for the undercoat layer, calcined kaolin is generally used, but diatomaceous earth, talc, kaolin, heavy calcium carbonate, precipitated calcium carbonate, magnesium carbonate, zinc oxide, aluminum oxide, hydroxide are also used. Inorganic pigments such as aluminum, magnesium hydroxide, titanium dioxide, barium sulfate, zinc sulfate, amorphous silica, amorphous calcium silicate, colloidal silica, melamine resin filler, urea-formalin resin filler, polyethylene powder, nylon powder, Organic pigments such as styrene-based plastic pigments, acrylic-based plastic pigments, and hydrocarbon-based plastic pigments can be used.

  As the resin for the undercoat layer, various water-soluble resins or hydrophobic resins used in normal coating can be used as in the case of the protective layer and the heat-sensitive recording layer. Specific examples are shown in the description of the protective layer.

  The method for forming the heat-sensitive recording layer, protective layer or undercoat layer is not particularly limited, and can be formed according to a conventionally known technique. Specific examples include air knife coating, rod blade coating, bar coating, blade coating, gravure coating, curtain coating, E-bar coating, and other methods. A recording layer, a protective layer or an undercoat layer can be formed. In addition, each layer may be formed by various printing machines or the like using a system such as a lithographic plate, a relief plate, a flexo, a gravure, a screen, and a hot melt.

  If necessary, after applying the undercoat layer, after applying the heat-sensitive recording layer, or after applying the protective layer, supercalender treatment can be performed to improve the image quality.

  Next, the present invention will be described in more detail with reference to examples. However, it is not limited to these. The parts and% shown below are based on mass, and the coating amount is the absolute dry coating amount.

Example 1
Preparation of coating solution for undercoat layer A composition comprising 100 parts of calcined kaolin (trade name: Ancilex, Engelhard), 24 parts of styrene / butadiene latex having a solid content of 50% and 200 parts of water was mixed and stirred. A coating solution for an undercoat layer was obtained.

<Dispersion A>
200 g of 3-dibutylamino-6-methyl-7-anilinofluorane is dispersed in a mixture of 200 g of a 10% sulfone group-modified polyvinyl alcohol aqueous solution and 600 g of water, and pulverized with a bead mill until the average particle size becomes 1 μm. A was obtained.

<Dispersion B>
200 g of 2,4′-dihydroxydiphenylsulfone was dispersed in a mixture of 200 g of a 10% sulfone group-modified polyvinyl alcohol aqueous solution and 600 g of water, and pulverized with a bead mill until the average particle size became 0.7 μm, whereby dispersion B was obtained.

<Dispersion C>
200 g of benzyl-2-naphthyl ether was dispersed in a mixture of 200 g of a 10% sulfone group-modified polyvinyl alcohol aqueous solution and 600 g of water, and pulverized with a bead mill until the average particle size became 1 μm to obtain dispersion C.

<Dispersion D>
200 g of precipitated calcium carbonate (trade name: Unibur-70, manufactured by Shiraishi Kogyo Co., Ltd.) was dispersed in 800 g of a 0.2% sodium polyacrylate aqueous solution and stirred for 5 minutes with a homogenizer to obtain dispersion D.

Preparation of coating solution for heat-sensitive recording layer Using the above dispersion, mix in the following composition, add added water so that the solid content concentration is 17%, and stir well to heat-record. A layer coating solution was prepared.
Dispersion A 30 parts Dispersion B 70 parts Dispersion C 70 parts Dispersion D 50 parts 10% fully saponified polyvinyl alcohol aqueous solution (NM-11, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 80 parts 40% zinc stearate dispersion 25 Part

<Dispersion E>
200 g of aluminum hydroxide [trade name: H-42, manufactured by Showa Denko KK] was dispersed in 800 g of a 0.2% sodium polyacrylate aqueous solution and stirred for 5 minutes with a homogenizer to obtain dispersion E.

Preparation of coating liquid for protective layer The mixture shown below was mixed, added water was added so as to obtain an aqueous dispersion having a solid content concentration of 8%, and stirred sufficiently to prepare a coating liquid for protective layer.
Dispersion E 20 parts 10% acetoacetyl-modified polyvinyl alcohol aqueous solution (Nippon Synthetic Chemical Industry Co., Ltd., Z320) 150 parts 10% 3-aminopropyltriethoxysilane aqueous solution (Shin-Etsu Chemical Co., Ltd., KBE-903) 15 parts 40% 5 parts of zinc stearate dispersion

On one surface of woodfree neutral paper making basis weight of 50 g / m ² of heat-sensitive recording material, the coating amount as the solid content 9 g / m ² for undercoat layer coating solution, the coating amount as the solid content of the heat-sensitive recording layer coating composition Are coated and dried sequentially so that the coating amount of the dye precursor is 0.5 g / m ² and the coating amount of the coating liquid for the protective layer is 2 g / m ^2, and then the undercoat layer, the heat-sensitive recording layer and the protective layer. A heat-sensitive recording material was prepared by forming a layer and performing a calendar process.

(Example 2)
In the production of the heat-sensitive recording material of Example 1, 15 parts of 10% 3-aminopropyltriethoxysilane aqueous solution (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-903) used for the protective layer coating solution was added to 10% N-2- ( A thermosensitive recording material was prepared in the same manner as in Example 1 except that the aminoethyl) -3-aminopropyltrimethoxysilane aqueous solution (KBE-603, manufactured by Shin-Etsu Chemical Co., Ltd.) was changed to 15 parts.

(Example 3)
In the production of the thermosensitive recording material of Example 1, 150 parts of a 10% acetoacetyl-modified polyvinyl alcohol aqueous solution (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Z320) used for the protective layer coating solution was replaced with 10% acetoacetyl-modified polyvinyl alcohol aqueous solution (Japan). A thermosensitive recording material was produced in the same manner as in Example 1 except that the composition was changed to 150 parts (Z200) manufactured by Synthetic Chemical Industry Co., Ltd.

Example 4
In the production of the heat-sensitive recording material of Example 1, the same as Example 1 except that 15 parts of 10% hydroxy zirconyl chloride aqueous solution (ZC-2, manufactured by Daiichi Elemental Chemical Co., Ltd.) was added to the protective layer coating solution. Thus, a heat-sensitive recording material was produced.

(Comparative Example 1)
In the production of the thermosensitive recording material of Example 1, 150 parts of a 10% acetoacetyl-modified polyvinyl alcohol aqueous solution (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Z320) used for the protective layer coating solution was added to a 10% fully saponified polyvinyl alcohol aqueous solution (Japan). A thermosensitive recording material was produced in the same manner as in Example 1 except that the composition was changed to 150 parts (manufactured by Synthetic Chemical Industry, NH-18).

(Comparative Example 2)
In preparation of the thermosensitive recording material of Example 1, 15 parts of 10% 3-aminopropyltriethoxysilane aqueous solution (KBE-903, manufactured by Shin-Etsu Chemical Co., Ltd.) used for the protective layer coating solution was added to 10% vinyltriethoxysilane aqueous solution. A heat-sensitive recording material was prepared in the same manner as in Example 1 except that the material was changed to (KBE-1003, manufactured by Shin-Etsu Chemical Co., Ltd.).

(Comparative Example 3)
In the production of the heat-sensitive recording material of Example 1, except that 15 parts of 10% 3-aminopropyltriethoxysilane aqueous solution (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-903) used for the protective layer coating solution was not added, A thermosensitive recording material was produced in the same manner as in Example 1.

  The heat-sensitive recording materials produced in Examples 1 to 4 and Comparative Examples 1 to 3 were subjected to the following evaluation. The results are shown in Table 1.

[Thermal response test]
Printing was performed using a facsimile testing machine TH-PMD manufactured by Okura Electric. A thermal head having a dot density of 8 dots / mm and a head resistance of 1685Ω was used, and an image was obtained by energizing with a head voltage of 21 V and a pulse width of 1.6 msec. The density of the image area was measured with a Macbeth RD-918 reflection densitometer (visual filter).

[Chemical resistance test]
A soft PVC sheet was closely attached to a printed image printed with a pulse width of 1.6 msec used in the evaluation of thermal response, and the density of the image portion after storage for 72 hours at room temperature was measured using a Macbeth RD-918 reflection densitometer ( (Visual filter).

[Sticking test]
Using a printer HT950 manufactured by Canon Inc., printing was performed under an environmental condition of 23 ° C. and 65% RH, and the degree of sticking on the printed surface was evaluated in three stages. The evaluation criteria followed the following indicators.
◎: Sticking does not occur at all ○: Sticking occurs very slightly ×: Sticking occurs on the entire surface

  Examples 1-4 are excellent in chemical resistance and sticking property compared with Comparative Examples 1-3. The former contains acetoacetyl-modified polyvinyl alcohol as an adhesive in the protective layer and a silane coupling agent having an amino group as a crosslinking agent.

  Example 4 is superior to Example 1 in chemical resistance and sticking property. The former contains a zirconium compound as a crosslinking agent in the protective layer.

Claims (2)

  A heat-sensitive recording layer containing an electron-donating ordinary colorless or light-colored dye precursor on a support and an electron-accepting compound that reacts upon heating to develop the dye precursor, and an adhesive on the heat-sensitive recording layer And a protective layer containing a crosslinking agent, wherein the protective layer contains an acetoacetyl-modified polyvinyl alcohol as an adhesive and a silane coupling agent having an amino group as a crosslinking agent. .   The heat-sensitive recording material according to claim 1, wherein the protective layer contains a zirconium compound as a crosslinking agent.