JPH06328849A - Thermal recording material - Google Patents

Abstract

PURPOSE:To provide a thermal recording material which is excellent in not only chemical resistance but also prevention of sticking and antistat effect and has favorable image quality. CONSTITUTION:A thermal recording material is provided with a thermal recording layer containing at least a coloring agent and developer coloring by reacting with the coloring agent on a substrate and water-soluble resin layer containing at least 0.01-5wt.% surfactant on the thermal recording layer in a form of solid content wherein the surfactant is alkyl sulfosuccinate and fluorine-based surfactant.

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 which is excellent in recorded image and background chemical resistance and is capable of recording a high quality image.

[0002]

2. Description of the Related Art A thermal recording method has been used in various fields such as a facsimile and a printer in recent years because it is highly reliable and requires no maintenance although the recording apparatus used is simple. However, since the thermal recording material has poor resistance to chemicals such as oil and plasticizer, the density of the recorded image decreases when the recorded image is stored in contact with a plastic film containing the plasticizer for a long period of time. was there.

As a method of solving such a drawback, a method of providing a protective layer containing a specific amount of a fluorine-containing surfactant on the color forming layer (Japanese Patent Publication No. 57-107884) or a thermosensitive recording layer is provided. A method of providing a water-soluble resin layer containing a specific amount of alkylsulfosuccinate (Japanese Patent Publication No.
No. 17479) is known. However, in any of the above methods, although the chemical resistance is improved, the protective layer coating liquid is repelled on the heat-sensitive recording layer during coating, so that the protective layer (referred to as cissing) is not uniformly coated.

Therefore, when an image is recorded using such a heat-sensitive recording material, there is a drawback that the recorded image suffers from uneven density due to the repelling and the quality of the recorded image becomes poor. In addition, when the coating solution for the protective layer is applied using a hopper type coating apparatus, the coating property is inferior and an uncoated portion is generated, so that the sticking prevention and antistatic effects are not sufficient.

[0005]

The inventors of the present invention have made extensive studies to solve the above-mentioned drawbacks, and as a result, have found that a water-soluble resin layer containing a specific amount of an alkylsulfosuccinate and a fluorosurfactant. It was found that a good heat-sensitive recording material can be obtained when the protective layer is provided as a protective layer, and thus the present invention has been accomplished. Therefore, an object of the present invention is to provide a heat-sensitive recording material which is excellent not only in chemical resistance, but also in sticking resistance and antistatic effect and in which image quality is excellent.

[0006]

The above objects of the present invention are as follows.
A thermosensitive recording layer containing at least a color-forming agent and a color-developing agent that develops a color by reacting with the color-forming agent on a support, and at least a surfactant in a solid content of 0.01 to 5 on the thermosensitive recording layer.
A heat-sensitive recording material provided with a water-soluble resin layer containing 50% by weight, wherein the surfactant is an alkylsulfosuccinate and a fluorine-based surfactant.

In the heat-sensitive recording material of the present invention, an image is recorded by heating a color-developing agent and a color-developing agent which are separated from each other at room temperature to bring them into contact with each other to develop a color. As a color former and a color developer, a combination of an electron-donating dye precursor (color former) and an electron accepting compound (color former), or a combination of a diazo compound (color former) and a coupling compound (color former) Is preferable, and it is particularly preferable to adopt the former combination from the viewpoint of image clarity.

The electron-donating dye precursor used in the present invention is not particularly limited, but it has a property of developing a color by donating an electron or accepting a proton such as an acid, and a lactone. Compounds having a partial skeleton such as lactam, sultone, spiropyran, ester, amide, etc., which are ring-opened or cleaved upon contact with a color developer, are generally colorless compounds. Examples of such electron-donating dye precursors include crystal violet lactone, benzoyl leuco methylene blue, malachite green lactone, rhodamine B lactam,
1,3,3-trimethyl-6'-ethyl-8'-butoxyindolinobenzospiropyran and the like.

As the electron-accepting compound (developing agent) for these color-forming agents, phenol compounds, organic acids or metal salts thereof, acidic substances such as oxybenzoic acid esters, etc. are used. 61-2911
No. 83. As a heat-sensitive recording material in which such an electron-donating dye precursor (color former) and an electron-accepting compound (developing agent) are combined, for example, US Pat.
771,034, 4,839,332, JP-A-63-22682, 63-265682, 63.
No. 227375 and JP-A No. 1-105782.

The diazo compound that can be used in the present invention is a compound that reacts with a developer called a coupling component described below to develop a desired hue, and emits light of a specific wavelength before the reaction. It is a photodecomposable diazo compound that decomposes when received and no longer has the ability to develop color even when the coupling component acts. The hue in this coloring system is mainly determined by the diazo dye produced by the reaction of the diazo compound and the coupling component. Therefore, as is well known, the coloring hue can be easily changed by changing the chemical structure of the diazo compound or the chemical structure of the coupling component, and almost any coloring hue can be obtained depending on the combination. it can.

The photodecomposable diazo compound in the present invention mainly refers to an aromatic diazo compound, and more specifically, a compound such as an aromatic diazonium salt, a diazosulfonate compound or a diazoamino compound. The diazonium salt is
A compound represented by the general formula ArN ₂ ⁺ X ⁻ (wherein
Ar represents a substituted or unsubstituted aromatic moiety,
N ₂ ⁺ represents a diazonium group, and X ⁻ represents an acid anion).

The photolysis wavelength of a diazonium salt is usually said to be its absorption maximum wavelength. It is known that the absorption maximum wavelength of diazonium salt changes from about 200 nm to about 700 nm depending on its chemical structure ("Photolysis and chemical structure of photosensitive diazonium salt" written by Takahiro Tsunoda and Ao Yamaoka, Japan Photo Journal 29 (4) 197-105
Page (1965). That is, when a diazonium salt is used as a photodecomposable compound, it is decomposed by light having a specific wavelength according to its chemical structure, and if the chemical structure of the diazonium salt is changed, even if it undergoes a coupling reaction with the same coupling component. ,
The hue of the resulting dye changes.

Many diazosulfonates that can be used in the present invention are known, and they can be obtained by treating each diazonium salt with a sulfite. As the diazoamino compound which can be used in the present invention, the diazo group is coupled with dicyandiamide, sarcosine, methyltaurine, N-ethylanthranic acid-5-sulphonic acid, monoethanolamine, diethanolamine, guanidine and the like. It is a compound. Details of these diazo compounds are described in, for example, JP-A-2-136286.

The coupling component for forming a dye by coupling with the diazo compound (diazonium salt) used in the present invention includes, for example, 2-hydroxy-3-naphthoic acid anilide and resorcin as a starting point. -14
The thing described in 6678 can be mentioned. Further, an image having an arbitrary color tone can be obtained by using two or more of these coupling components in combination.
Since the coupling reaction between these diazo compound and the coupling component easily occurs in a basic atmosphere, it is preferable to add a basic substance in the layer.

As the basic substance, a hardly water-soluble or water-insoluble basic substance or a substance which generates an alkali upon heating is used. Examples thereof are inorganic and organic ammonium salts, organic amines, amides, urea and thiourea and their derivatives, thiazoles, pyrroles, pyrimidines,
Examples thereof include nitrogen-containing compounds such as piperazines, guanidines, indoles, imidazoles, imidazolines, triazoles, morpholines, piperidines, amidines, formazines and pyridines. Specific examples of these are described, for example, in JP-A-61-291183. Two or more basic substances may be used in combination.

Thermal recording materials using a combination of the above-mentioned diazo compound (color former) and coupling compound (developing agent) are disclosed, for example, in JP-B-2-28479, JP-A-2-31674 and JP-A-2-31674. -20434. The color former or the developer used in the present invention can be usually used by being dispersed in a solid state, but from the viewpoint of the raw storability of the heat-sensitive recording layer such as preventing contact between the color former and the developer at room temperature (prevention of fogging). ), And from the viewpoint of controlling the color development sensitivity of developing color with desired heat energy, etc., in the present invention, it is preferable to use either the color former or the developer encapsulated in microcapsules.

Any of an interfacial polymerization method, an internal polymerization method, and an external polymerization method can be adopted for producing the microcapsules which can be used in the present invention. In particular, an ultraviolet absorber is contained. It is preferable to employ an interfacial polymerization method in which the core substance is emulsified in an aqueous solution in which a water-soluble polymer is dissolved and then a wall of the polymer substance is formed around the oil droplets. The reactant forming the polymer substance is added inside the oil droplet and / or outside the oil droplet.

Specific examples of the polymer substance include polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, melamine resin, polystyrene, styrene methacrylate copolymer,
Examples thereof include styrene-acrylate copolymer. Preferred polymeric substances are polyurethanes, polyureas, polyamides, polyesters and polycarbonates, particularly preferably polyurethanes and polyureas. Two or more polymer substances can be used in combination. Specific examples of the water-soluble polymer include gelatin, polyvinylpyrrolidone, polyvinyl alcohol and the like.

For example, when polyurea is used as a capsule wall material, polyisocyanates such as diisocyanate, triisocyanate, tetraisocyanate and polyisocyanate prepolymer, and polyamines such as diamine, triamine and tetraamine, amino. A microcapsule wall can be easily formed by reacting a prepolymer containing two or more groups, piperazine or a derivative thereof, a polyol or the like with an interfacial polymerization method in an aqueous solvent.

Further, for example, the composite wall composed of polyurea and polyamide or the composite wall composed of polyurethane and polyamide is added, for example, by using polyisocyanate and acid chloride or polyamine and polyol, after adjusting the pH of the emulsifying medium as the reaction solution. It can be prepared by heating. For details of the method for producing a composite wall composed of these polyurea and polyamide, see JP-A-58-
No. 66948. In order to microencapsulate the color former, it is preferable to dissolve the color former in an organic solvent before use.

Examples of the organic solvent include low-boiling solvents such as ethyl acetate, methyl acetate, carbon tetrachloride, chloroform, methanol, ethanol, n-butanol, dioxane, acetone and benzene, phosphoric acid ester and phthalic acid ester. High boiling point solvents such as carboxylic acid esters, fatty acid amides, alkylated biphenyls, alkylated terphenyls, chlorinated paraffins, alkylnaphthalenes, and diarylethanes can be mentioned. Such an organic solvent is described in detail in JP-A-4-19778.

In the case of microcapsules containing a color-forming agent, a solid sensitizer may be added to swell the microcapsule wall when heated. The solid sensitizer may be selected from those referred to as plasticizers for polymers used as microcapsule walls, and those having a melting point of 50 ° C. or higher, preferably 120 ° C. or lower, and solid at room temperature can be selected and used. For example, when the wall material is made of polyurea or polyurethane, a hydroxy compound, a carbamic acid ester compound, an aromatic alkoxy compound, an organic sulfonamide compound, an aliphatic amide compound, an arylamide compound and the like are preferably used.

In the present invention, when a diazo compound is used as the color former, a color former may be used. The coloring aid that can be used in the present invention is a substance that increases the coloring density during heating printing or lowers the minimum coloring temperature, lowers the melting point of the coupling component or the diazo compound, or capsule wall. This is to create a situation in which the diazo compound and the coupling component easily react with each other by the action of lowering the softening point of.

Examples of the color-forming assistant include phenol compounds, alcoholic compounds, amide compounds, sulfonamide compounds and the like. Specific examples are p-tert-octylphenol, p-benzyloxyphenol, phenyl p-oxybenzoate, Examples thereof include benzyl carbanylate, phenethyl carbanylate, hydroquinone dihydroxyethyl ether, xylylenediol, N-hydroxyethyl-methanesulfonic acid amide, N-phenyl-methanesulfonic acid amide. These may be contained in the core substance or may be added as a dispersion outside the microcapsules.

In the present invention, when the color developer is not microencapsulated, the transparency of the heat-sensitive recording layer is improved to improve the light transmittance of the heat-sensitive recording material to obtain a heat-sensitive recording material used for OHP. Or, from the viewpoint of laminating a plurality of heat-sensitive layers to form a multicolor heat-sensitive recording material, after dissolving it in an organic solvent that is sparingly soluble or insoluble in water, it is mixed with a water-soluble polymer while containing a surfactant. It can also be used in the form of a dispersion obtained by mixing and emulsifying with an aqueous phase having a protective colloid.

The organic solvent used in this case can be appropriately selected from high boiling point oils. Among them, preferable oils include dimethylnaphthalene, diethylnaphthalene, diisopropylnaphthalene, dimethylbiphenyl, diethylbiphenyl, diisopropylbiphenyl, diisobutylbiphenyl, 1-methyl-1-dimethylphenyl-1-phenylmethane, and 1 in addition to esters.
-Ethyl-1-dimethylphenyl-1-phenylmethane, 1-propyl-1-dimethylphenyl-1-phenylmethane, triallylmethane (eg, tritoluylmethane, toluyldiphenylmethane), terphenyl compound (eg, terphenyl) , Alkyl compounds, alkylated diphenyl ethers (eg propyl diphenyl ether), hydrogenated terphenyls (eg hexahydroterphenyl), diphenyl ethers and the like.
Among these, it is particularly preferable to use esters from the viewpoint of emulsion stability of the emulsion dispersion.

Examples of the esters include phosphoric acid esters (eg, triphenyl phosphate, tricresyl phosphate, butyl phosphate, octyl phosphate, cresyl diphenyl phosphate), phthalic acid esters (dibutyl phthalate, 2-ethylhexyl phthalate, phthalic acid). Ethyl, octyl phthalate, butylbenzyl phthalate), tetrahydrophthalate dioctyl, benzoic acid ester (ethyl benzoate, propyl benzoate, butyl benzoate, isopentyl benzoate, benzyl benzoate), abietic acid ester (ethyl abietic acid, Benzyl abietic acid), dioctyl adipate, isodecyl succinate, dioctyl azelate, oxalate ester (dibutyl oxalate, dipentyl oxalate), diethyl malonate, maleate ester (dimethyl maleate, maleic acid) Diethyl acid, dibutyl maleate), tributyl citrate, sorbate (methyl sorbate, ethyl sorbate, butyl sorbate), sebacate (dibutyl sebacate, dioctyl sebacate), ethylene glycol esters (formic acid monoester) And diesters, butyric acid monoesters and diesters, lauric acid monoesters and diesters, palmitic acid monoesters and diesters, stearic acid monoesters and diesters, oleic acid monoesters and diesters), triacetin, diethyl carbonate, diphenyl carbonate, ethylene carbonate, carbonic acid propylene,
Examples thereof include boric acid esters (tributyl borate, tripentyl borate) and the like. Among these, the use of tricresyl phosphate alone or in combination is preferable because the emulsion dispersion stability of the developer is particularly good. It is also possible to use the above oils in combination, or to use in combination with other oils.

In the present invention, an auxiliary solvent may be added to the above organic solvent as a low boiling point dissolution aid. As such an auxiliary solvent, for example, ethyl acetate, isopropyl acetate, butyl acetate, methylene chloride and the like can be mentioned as particularly preferable ones. The water-soluble polymer to be contained as a protective colloid in the aqueous phase mixed with the oil phase containing these components may be appropriately selected from known anionic polymers, nonionic polymers and amphoteric polymers. However, polyvinyl alcohol, gelatin, cellulose derivatives and the like are preferable.

As the surface active agent to be contained in the aqueous phase, an anionic or nonionic surface active agent which does not cause precipitation or aggregation by acting on the protective colloid may be appropriately selected and used. it can. Preferred surfactants include sodium alkylbenzene sulfonate, sodium alkylsulfate, dioctyl sodium sulfosuccinate, polyalkylene glycol (eg, polyoxyethylene nonylphenyl ether), and the like.

The emulsified dispersion of the present invention comprises an oil phase containing the above components, a protective colloid, and an aqueous phase optionally containing a surfactant, which are subjected to high speed stirring, ultrasonic dispersion, etc.
It can be easily obtained by mixing and dispersing by using a means usually used for fine particle emulsification. Further, the ratio of the oil phase to the water phase (oil phase weight / water phase weight) is preferably 0.02 to 0.6, and particularly preferably 0.1 to 0.4. If it is 0.02 or less, the amount of the aqueous phase is too large to be diluted and sufficient color developability cannot be obtained, and if it is 0.6 or more, the viscosity of the liquid is increased, which causes inconvenience in handling and a decrease in coating liquid stability.

The water-soluble resin used in the protective layer in the present invention is not particularly limited and can be appropriately selected and used from known water-soluble resins. Examples of the water-soluble resin include polyvinyl alcohol, silicon-modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, starch and its induction resistance, casein, sodium alginate, polyvinylpyrrolidone, sodium polyacrylate, polyacrylamide, styrene malein. Examples thereof include acid copolymer salts, polyurethane resins, urea resins and melamine resins.

The alkyl succinate and the fluorosurfactant to be contained in the water-soluble resin layer in the present invention are not particularly limited and can be appropriately selected from known ones and used. Preferred alkyl sulfosuccinates include those represented by the following chemical formula 1.

[Chemical 1] In the chemical formula 1, R ₁ and R ₂ are alkyl groups, and M is an alkali metal or NH ₄ . R ₁ and R ₂ may be the same or different.

The alkyl group represented by R ₁ and R ₂ preferably has 3 to 15 carbon atoms, particularly 4 to 5 carbon atoms. Specific examples of such an alkyl group include an isobutyl group, an amyl group, a hexyl group, a cyclohexyl group,
Examples thereof include an octyl group and a 2-ethyl-hexyl group.
Preferred examples of the fluorine-based surfactant include perfluoroalkylcarboxylic acid salts, perfluoroalkylsulfonic acid salts, perfluoroalkylphosphoric acid esters, perfluoroalkylethylene oxide adducts, perfluoroalkyltrimethylammonium salts, and perfluoro. Examples include alkyl betaine. Among these,
Those which can be dissolved in water by 0.2% by weight or more are particularly preferable.

The total amount of the alkyl sulfosuccinate and the fluorosurfactant combined is based on the water-soluble resin layer.
The solid content is preferably in the range of 0.01 to 5% by weight. If it is less than 0.01% by weight, the chemical resistance is insufficient, and if it exceeds 5% by weight, the image quality of the recorded image is deteriorated due to uneven density due to cissing of the coating liquid. The ratio of the sulfosuccinate / fluorine-based surfactant used is not particularly limited, but the weight ratio is preferably in the range of 1/9 to 9/1, and particularly 3/7 to 7/3. It is preferably in the range of.

In the present invention, the water-soluble resin layer is preferably composed mainly of silicon-modified polyvinyl alcohol and colloidal silica when transparency is particularly required. In the present invention, by providing a water-soluble resin layer as a protective layer on the uppermost layer of the thermal recording layer,
The mechanical strength of the surface of the heat-sensitive recording layer can be improved.

Pigments, metal soaps, waxes, cross-linking agents, etc. may be added to the water-soluble resin layer for the purpose of improving the matching property with the thermal head during thermal recording and improving the water resistance. Details of these pigments, metal soaps, waxes, cross-linking agents and the like are described in, for example, JP-A-2-141279. When the water-soluble resin layer solution or the heat-sensitive layer solution prepared as described above is applied onto the support or the heat-sensitive recording layer, a known coating means using a water-based or organic solvent-based coating solution is used.

In this case, in order to apply the coating solution safely and uniformly and to maintain the strength of the coating film,
Polymer binders such as methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, starches, gelatin, polyvinyl alcohol, carboxy modified polyvinyl alcohol, polyacrylamide, polystyrene and copolymers thereof, polyester and copolymers thereof, polyethylene and copolymers thereof, epoxy resin,
Acrylate and methacrylate resins and their copolymers, polyurethane resins, polyamide resins and the like can be used together with the microcapsules. Further, pigments, waxes, hardeners and the like may be added to the heat-sensitive recording layer, if necessary.

The heat-sensitive recording layer is coated such that the total amount of the color-developing agent and the color-developing agent is 0.1 to 10 g / m ² , and the thickness of the layer is 1 to 10 μm. Is desirable. The solid coating amount of the water-soluble resin layer is usually preferably 0.2 to 5 g / m ² , and particularly 1 to 5 g / m ² .
It is preferably 3 g / m ² .

The support used in the present invention may be transparent or opaque. Examples of the opaque support include paper, coated paper, synthetic paper, a paper laminated with a polymer film, an aluminum vapor deposition base, and a polymer film coated with a white pigment. As the paper used for the support, neutral paper sized with a neutral sizing agent such as alkyl ketene dimer and having a heat extraction pH of 6 to 9 (for example, JP-A-55-14281) can be used for storage with time. It is advantageous in terms of sex.

In the present invention, the smoothness (JIS P8
When high quality paper of 119) is 200 seconds or longer, an image with particularly good quality can be recorded. Examples of the transparent support include polyester films such as polyethylene terephthalate and polybutylene terephthalate,
Cellulose derivative film such as cellulose triacetate film, polystyrene film, polypropylene film,
Polyolefin film such as polyethylene film, polyimide film, polyvinyl chloride film, polyvinylidene chloride film, polyacrylic acid copolymer film, polycarbonate film and the like can be used, and these can be used alone or by bonding, but especially polyester It is preferable that the film has been subjected to heat treatment and antistatic treatment.

The thickness of the support is 20 to 200 μm, and preferably 50 to 100 μm. In the present invention, when a plastic film or the like is used as a support, before the application of the heat-sensitive layer containing microcapsules or the like on the support for the purpose of preventing the heat-sensitive recording layer from peeling from the support. It is desirable to provide an undercoat layer. As the undercoat layer, an acrylic acid ester copolymer, polyvinylidene chloride, SBR, aqueous polyester or the like can be used, and the film thickness is 0.1 to 0.5.
It is desirable that the thickness is μm.

With respect to the undercoat layer, the image recorded on the heat-sensitive layer may be deteriorated when the undercoat layer swells due to the water content in the heat-sensitive layer when the heat-sensitive layer is coated thereon. , Glutaraldehyde, 2,3-dihydroxy-
It is desirable to cure using a dialdehyde such as 1,4-dioxane and a hardener such as boric acid. The amount of these hardeners added is in the range of 0.20% to 3.0% by weight based on the weight of the undercoat material, and an appropriate amount can be selected according to the desired degree of curing.

The heat-sensitive layer, the water-soluble resin layer, the undercoat layer and the like are known coating methods such as blade coating method, air knife coating method, gravure coating method, roll coating coating method, spray coating method, dip coating method and bar coating method. It is applied by the method. The coating amount is preferably 1 to ²⁰ g / m ² , and particularly 3 to 1
It is preferably 0 g / m ² .

[0044]

The heat-sensitive recording material of the present invention is excellent in chemical resistance because a water-soluble resin layer containing a specific amount of an alkylsulfosuccinate and a fluorosurfactant is provided on the heat-sensitive recording layer. In addition, the coating property is good, the sticking prevention and the antistatic effect are excellent, and an image of good quality can be recorded.

[0045]

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited thereto.

Example 1. Preparation of coating liquid for heat-sensitive layer 20 g of 2-anilino-3-methyl-6-N-ethyl-N-isoamylaminofluorane as an electron-donating dye precursor and bisphenol A20 as an electron-accepting compound
g and 20 g of benzyl-2-naphthyl ether as a heat-fusible substance are added to 100 g of a separately prepared 5% by weight aqueous solution of gelatin, and each solution is mixed using a ball mill so that the average particle diameter becomes 3 μm or less. The mixture was dispersed all day and night to obtain an electron-donating dye precursor dispersion liquid, an electron-accepting compound dispersion liquid, and a heat-fusible substance dispersion liquid. On the other hand, calcined kaolin (A
80 g of nisIex-93) was added to 160 g of a 0.5 wt% solution of sodium hexametaphosphate and dispersed using a homogenizer to obtain a pigment dispersion liquid.

5 g of the electron-donating dye precursor dispersion prepared as described above, 10 g of the electron-accepting compound dispersion, 10 g of the heat-fusible substance dispersion and 22 g of the pigment dispersion were mixed, and then zinc stearate 20 4 g of a weight% emulsion solution and 5 g of a 2% by weight aqueous solution of sodium (2-ethylhexyl) sulfosuccinate were added and mixed to obtain a heat-sensitive layer coating solution.

Preparation of coating solution for water-soluble resin layer 8% by weight aqueous polyvinyl alcohol solution (PVA 117:
14 g of Kuraray Co., Ltd. product name), 1 g of sodium di- (2-ethyl-hexyl) sulfosuccinate, and perfluoroalkylcarboxylic acid salt (MegaFac F120:
Product of Dainippon Ink and Co., Ltd., zinc stearate 2
1.8 g of 0% by weight emulsion, 50% by weight of kaolin
13 g of the dispersion liquid was added and mixed to obtain a water-soluble resin layer coating liquid.

Preparation of heat-sensitive recording material On high- quality paper having a basis weight of 60 g / m ² and a smoothness of 600 seconds, the heat-sensitive layer had a solid content of 6.0 g / m ² and the water-soluble resin layer had a solid content of 2.0 g / m 2. ^A coating solution was sequentially applied and dried using a wire bar so as to have the value of ^2. Thus, the heat-sensitive recording material of the present invention was obtained. Example 2. A heat-sensitive recording material of the present invention was obtained in exactly the same manner as in Example 1 except that the heat-sensitive layer coating liquid was changed to the following heat-sensitive layer coating liquid.

Preparation of coating solution for heat-sensitive layer Preparation of capsule solution 2 parts by weight of 2-methyl-3-anilino-7-cyclohexyl-N-methylaminofluorane as an electron-donating dye precursor, and xylylenediene as a capsule wall material. 18 parts by weight of a 3: 1 adduct of isocyanate and trimethylolpropane (Takenate D-110N: trade name manufactured by Takeda Pharmaceutical Co., Ltd.) was added to a mixture of 24 parts by weight of diisopropylnaphthalene and 5 parts by weight of ethyl acetate. After that, it was heated and melted.

5% by weight of polyvinyl alcohol (PVA217E: trade name of Kuraray Co., Ltd.)
3.5 parts by weight of aqueous solution, 1.7 parts by weight of gelatin, 1,4-
2.4 parts by weight of di (hydroxyethoxy) benzene was added to 5 parts of water.
Add 8 parts by weight to the mixed solution and stir at 60 ° C.
And heated for 2 hours to cause the encapsulation reaction to prepare a capsule liquid.

Preparation of color developer dispersion 20 parts by weight of bisphenol A was added to 100 parts by weight of a 5% by weight aqueous solution of polyvinyl alcohol, and the mixture was dispersed with a sand mill for 3 hours so that the average particle diameter was 1 μm. A dispersion was obtained. Preparation of Pigment Dispersion 40 parts by weight of calcium carbonate (Univar 70: a product of Shiraishi Kogyo Co., Ltd.) was added to 60 parts by weight of water, and dispersed so that the average particle size was 1.5 μm to obtain a pigment dispersion. It was

Preparation of coating liquid 40 parts by weight of the capsule liquid prepared as described above, 20 parts by weight of the developer dispersion liquid, 15 parts by weight of the pigment dispersion liquid, and di- (2
-Ethyl-hexyl) 3 parts by weight of a 2% by weight aqueous solution of sodium sulfosuccinate was added and mixed to obtain a heat-sensitive layer coating solution.

Example 3. Preparation of coating liquid for heat-sensitive layer Preparation of capsule liquid 1 part by weight of a compound represented by the following chemical formula 2 as a diazo compound and 1 part by weight of a compound represented by the following chemical formula 3 and 3 of toluylene diisocyanate and trimethylolpropane as a capsule wall material 1 part adduct 6 parts by weight and xylylene diisocyanate and trimethylolpropane 3: 1 adduct (Takenate D-110N: trade name of Takeda Pharmaceutical Co., Ltd.) 18 parts by weight, dibutyl phthalate 24 parts by weight and acetic acid. 5 parts by weight of ethyl was added to the mixed solution and dissolved by heating.

[0055]

[Chemical 2]

[Chemical 3] 3.5 parts by weight of polyvinyl alcohol and 1.7 parts by weight of gelatin were added to and mixed with a solution of 58 parts by weight of water, and the resulting solution was emulsified using a homogenizer so that the average particle size was 1 μm. After dispersion, and then 100 parts by weight of water was added, the encapsulation reaction was carried out at 50 ° C. for 2 hours with stirring to prepare a capsule liquid.

Preparation of Coupler Dispersion 16 parts by weight of 2-hydroxy-3-naphthoic acid anilide and 4 parts by weight of the compound represented by the following chemical formula 4 were added to 100 parts by weight of a 5% by weight aqueous solution of polyvinyl alcohol to obtain an average particle diameter. Of 1 μm was dispersed for 3 hours using a sand mill to obtain a coupler dispersion.

[Chemical 4]

Preparation of triphenylguanidine dispersion 20 parts by weight of triphenylguanidine was added to 100 parts by weight of an aqueous solution of 5% by weight of polyvinyl alcohol, and dispersed for 3 hours using a sand mill so that the average particle diameter was 1 μm. A phenylguanidine dispersion was obtained. Preparation of coating liquid 50 parts by weight of the obtained capsule liquid, 15 parts by weight of coupler dispersion, 15 parts by weight of dispersion of triphenylguanidine and the pigment dispersion used in Example 2 were stirred and mixed to prepare a coating liquid for heat-sensitive layer. did.

Preparation of Water-Soluble Resin Layer Coating Solution 14 parts by weight of 8% by weight aqueous solution of gelatin, 1 part by weight of sodium di-n-hexylsulfosuccinate and perfluoroalkyl betaine (Surflon S131: trade name of Asahi Glass Co., Ltd.) 2 parts by weight, zinc stearate 20% by weight
A water-soluble resin layer liquid was obtained by adding and mixing 1.8 parts by weight of the emulsion liquid and 13 parts by weight of the dispersion liquid of 50% by weight of kaolin.

Preparation of heat-sensitive recording material On high- quality paper having a basis weight of 60 g / m ² and a smoothness of 600 seconds, the heat-sensitive layer had a solid content of 6.0 g / m ² and the water-soluble resin layer had a solid content of 2.0 g / m 2. ² was simultaneously multilayer coated using a hopper type coating apparatus and dried to obtain a heat-sensitive recording material of the present invention.

Example 4. Preparation of coating liquid for heat-sensitive layer Preparation of capsule liquid 12 parts by weight of 2-anilino-3-methyl-6-N-ethyl-N-isoamylaminofluorane as an electron-donating dye precursor, and toluylene diisocyanate as a capsule wall material And trimethylolpropane 3: 1 adduct 2
0 part by weight was added to a liquid obtained by mixing 12 parts by weight of 1-phenyl-1-xylylethane and 20 parts by weight of methylene chloride, and dissolved by heating.

8% by weight of the obtained solution was polyvinyl alcohol (PVA217E: trade name of Kuraray Co., Ltd.).
60 parts by weight of an aqueous solution and 20 parts by weight of water were added to a mixed solution, and the mixture was emulsified and dispersed using a homogenizer so that the average particle size was 1 μm. Then, 120 parts by weight of water was added, and then at 40 ° C. for 3 hours. An encapsulation reaction was performed to prepare a capsule liquid.

Preparation of Developer Emulsion Dispersion Liquid 5 parts by weight of the developer represented by the following formula 5, 2 parts by weight of the developer represented by the following formula 6 and developer 8 represented by the following formula 7 1 part by weight of 1-phenyl-1-xylylethane and 7 parts by weight of ethyl acetate were added to 1 part by weight, and the mixture was heated and dissolved. The resulting solution was added to a solution prepared by mixing 37 parts by weight of an 8% by weight polyvinyl alcohol aqueous solution, 35 parts by weight of water, and 0.2 parts by weight of sodium dodecylbenzenesulfonate so that the average particle diameter becomes 1.5 μm. Then, it was emulsified and dispersed using an ace homogenizer (manufactured by Nippon Seiki Co., Ltd.) to obtain a color developer emulsion dispersion.

[0063]

[Chemical 5]

[Chemical 6]

[Chemical 7] Preparation of coating liquid The thermosensitive layer coating liquid was prepared by stirring and mixing 5 parts by weight of the obtained capsule liquid, 10 parts by weight of the color developer emulsion dispersion, and 5 parts by weight of water.

Preparation of Water-Soluble Resin Layer Coating Solution 8% by weight of polyvinyl alcohol aqueous solution (PVA217: trade name of Kuraray Co., Ltd.) was added to di- (2-
Ethyl-hexyl) sodium sulfosuccinate 2% by weight
1 part by weight of aqueous solution, 1 part by weight of perfluoroalkylethylene oxide adduct (Surflon S-145: trade name of Asahi Glass Co., Ltd.), 1 part by weight of 4% by weight boric acid solution and 2 parts by weight of 20% by weight zinc stearate emulsion. Was added and mixed to obtain a water-soluble resin layer liquid.

Preparation of heat-sensitive recording material On a polyethylene terephthalate film, the heat-sensitive layer had a solid content of 12 g / m ² , and the water-soluble resin layer had a solid content of 2.0 g.
/ M ² was simultaneously multi-layered using a hopper type coating device and dried to obtain a transparent heat-sensitive recording material of the present invention.

Comparative Example 1. Other than using sodium di- (2-ethyl-hexyl) sulfosuccinate and perfluoroalkylethylene oxide adduct (Surflon S-145: trade name of Asahi Glass Co., Ltd.) used in the water-soluble resin layer in Example 4 When a heat-sensitive recording material was produced in the same manner as in Example 4, the water-soluble resin layer as the protective layer could not be applied uniformly.

Comparative Example 2. A heat-sensitive recording material was obtained in the same manner as in Example 4 except that the sodium di- (2-ethyl-hexyl) sulfosuccinate used in the water-soluble resin layer in Example 4 was not used.

Comparative Example 3. A heat-sensitive recording material in the same manner as in Example 4 except that the perfluoroalkylethylene oxide adduct (Surflon S-145: a product name of Asahi Glass Co., Ltd.) used in the water-soluble resin layer in Example 4 was not used. Got

Recording of Image Each of the heat-sensitive recording materials of Examples and Comparative Examples prepared as described above was attached to a heat-sensitive printer (thermal imager FT).
Images were recorded using I-1000 type: trade name of Fuji Photo Film Co., Ltd., and the results of visual evaluation of image quality and chargeability are as shown in Table 1.

[0070]

[Table 1] The results in Table 1 demonstrate the effectiveness of the present invention.

Claims (1)

[Claims] 1. A heat-sensitive recording layer containing at least a color-forming agent and a color-developing agent that develops a color upon reacting with the color-forming agent on a support, and at least a surfactant in solid content on the heat-sensitive recording layer. A heat-sensitive recording material provided with a water-soluble resin layer containing 0.01 to 5% by weight, wherein the surfactant is an alkyl sulfosuccinate and a fluorine-based surfactant.