JP2002234252A - Heat-sensitive recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-sensitive recording medium having excellent surface glossiness and recording image quality of a recorded section from a low energy to a high energy. SOLUTION: The heat-sensitive recording medium comprises a heat-sensitive recording layer containing an electron donative compound and an electron acceptive compound on one surface of a support. In this medium, the outermost layer of the recording layer side is formed by transferring from a smooth surface. The glossiness (based on JIS P 8142 stipulated in 1993) of the recorded section recorded from the recording layer side by an energy of 80 mJ/mm2 by a thermal head is 35% or more at 20 deg. and 90% or more at 75 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosensitive recording medium utilizing a color development reaction between an electron donating compound and an electron accepting compound.

[0002]

2. Description of the Related Art A thermosensitive recording medium having a thermosensitive recording layer containing a leuco dye, a coloring agent and an adhesive provided on one side of a support made of paper, synthetic paper, plastic film or the like is used as a recording medium. The recording device was compact,
In addition, because it is inexpensive and easy to maintain, it can be used not only as a recording medium for facsimile machines, automatic ticket vending machines, scientific measuring instruments, etc., but also for various printers and plotters such as POS labels, CAD, and CRT medical images. Widely used as.

[0003] Among them, an image printer for CRT medical measurement that requires uniformity of recorded images and high resolution, and a CAD plotter that requires dimensional stability and thin line recording, synthetic paper having a multilayer structure, 2 containing inorganic pigments accordingly
An axially stretched thermoplastic resin film is used. With the diversification of uses, there is an increasing demand for heat-sensitive recording media having excellent surface gloss, recording image quality, and recording traveling properties comparable to silver halide photographs.

A heat-sensitive recording medium in which the outermost layer is a layer transferred from a smooth surface is disclosed in JP-A-8-90907, JP-A-9-14020, and JP-A-2000-71617.
However, there is a problem that the surface gloss of a recording portion after recording is significantly reduced, and the apparent recording image quality is unclear.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to improve the surface gloss of a recording portion from low energy to high energy,
Another object of the present invention is to provide a thermosensitive recording medium having excellent recording image quality.

[0006]

Means for Solving the Problems In a heat-sensitive recording medium having at least a heat-sensitive recording layer containing an electron-donating compound and an electron-accepting compound on one surface of a support, the outermost layer on the side of the heat-sensitive recording layer has a smooth surface. The glossiness (based on JIS P8142-1993) of a recording portion formed by transferring from a substrate having a surface and recording from the heat-sensitive recording layer side with an energy of 80 mJ / mm ² by a thermal head is 35 at 20 °.
% Or more, and 85% or more at 75 °.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention comprises
In a thermosensitive recording medium having at least a thermosensitive recording layer containing an electron donating compound and an electron accepting compound, the outermost layer on the thermosensitive recording layer side is a layer transferred from a substrate having a smooth surface, and 80mJ / mm
The glossiness (based on JIS P 8142-1993) of the recording portion recorded from the heat-sensitive recording layer side with the energy of ² was 20 °.
When the glossiness of the recording portion at 20 ° and 75 ° is less than 30% and less than 85%, respectively, the recorded image quality as viewed obliquely becomes unclear. There is a risk that.

[0007] The glossiness of a recording portion recorded with a high energy of 80 mJ / mm ² by a thermal head (JIS P
8142-1993) greater than 30% at 20 °, 75%
When the coating liquid for forming the outermost layer is an aqueous coating liquid containing at least an aqueous resin, the water content of the formed outermost layer is reduced to 2% or less, The crosslinking agent for the aqueous resin in the aqueous adhesive is 1
There is a method of increasing the heat resistance by adding about 20 to 20% by weight, and it is particularly preferable to make the thickness of the outermost layer about 0.5 to 2.0 μm.

The outermost layer is preferably a protective layer containing an aqueous resin and transferred from a substrate having a smooth surface. In particular, the glossiness (J
Preferably, the protective layer is provided so that the ratio of ISP 8142-1993 is 30% or more at 20 ° and 90% or more at 75 °.

As a smooth surface for obtaining the transferred outermost layer, for example, a light interference microscope (JIS B 0651)
Root mean square roughness (based on JIS B 0601-1982) of a smooth surface measured according to -1973)
0.05 to 0.50 μm is preferred. If the root mean square roughness of the smooth surface is less than 0.05 μm, the outermost layer may not be able to be uniformly peeled off from the smooth surface.
If it exceeds 0 μm, the glossiness of the unrecorded portion and the recorded portion of the outermost layer is reduced, and the recorded image quality may be unclear,
About 0.08 to 0.20 μm is more preferable.

As a substrate having such a smooth surface, polyethylene (PE) film, polypropylene (PP)
Examples include resin films such as films, polystyrene (PS) films and polyethylene terephthalate (PET) films, and mirror-plated metal drums. Above all, a resin film is preferable, and its thickness is preferably about 10 to 50 μm. To make the root mean square roughness (based on JIS B 0601-1982) of the resin film surface 0.05 to 0.50 μm, a pigment is internally added to the resin film, or an anchor coat layer is provided. Obtained.

A preferred construction of the heat-sensitive recording material of the present invention is a heat-sensitive recording material having a protective layer containing an aqueous resin as an outermost layer, an adhesive layer mainly composed of an adhesive, a heat-sensitive recording layer and a support in this order. And a thermosensitive recording medium having a protective layer containing an aqueous resin as an outermost layer, a thermosensitive recording layer, an adhesive layer mainly composed of an adhesive, and a support in that order. In particular,
It is preferable that the thermosensitive recording medium having the above-described structure has an intermediate layer containing an aqueous resin between the thermosensitive recording layer and the adhesive layer.

When the layer in contact with the adhesive layer is a protective layer or an intermediate layer, the Oken-type smoothness of the protective layer or the intermediate layer on the side in contact with the adhesive layer is 7000 seconds or more, and the root mean square roughness (-1982 based on JIS B 0601) is 0.4
Preferably it is 5 μm or less.

When the layer in contact with the adhesive layer is a support, the support has an Oken-type smoothness of 400 seconds or more and a root mean square roughness (based on JIS B 0601-1982) of 1.00 μm. The following is preferred.

When the layer in contact with the adhesive layer is a heat-sensitive recording layer, the heat-sensitive recording layer on the side in contact with the pressure-sensitive adhesive layer has an Oken-type smoothness of 1000 seconds or more and a root mean square roughness (JIS).
B 0601-1982) is preferably 0.80 μm or less.

The outermost layer is, for example, a layer formed in contact with one surface of a resin film having a smooth surface. Examples of the outermost layer include a heat-sensitive recording layer, a protective layer cured by irradiating a solventless electron beam-curable compound with an electron beam, and a protective layer containing an aqueous resin.

A thermosensitive recording medium having such an outermost layer has, for example, a protective layer on one surface of a resin film having a smooth surface.
A heat-sensitive recording layer, an intermediate layer and an adhesive layer containing an electron beam-curable compound as main components are sequentially provided, and the adhesive layer surface is separately adhered to one surface of the support. Is peeled from the outermost layer surface, or a protective layer and an adhesive layer mainly composed of an electron beam curable compound are sequentially provided on one surface of a resin film having a smooth surface, and a heat-sensitive recording layer is separately formed on a support. And an intermediate layer are sequentially provided, the surface of the intermediate layer and the surface of the adhesive layer are brought into close contact with each other, and after irradiating with an electron beam, only the resin film having a smooth surface is peeled off from the outermost layer surface.

The protective layer is made of, for example, a medium containing water, an aqueous resin,
A coating amount of the protective layer coating liquid obtained by mixing and stirring with the following auxiliaries, if necessary, after drying on the substrate surface having a smooth surface is about 0.5 to 5 g / m ² , preferably 0.5 to 5 g / m ^2. ~ 2.
It is obtained by coating and drying to about 0 g / m ² .

Examples of the aqueous resin contained in the coating liquid for the protective layer include starches, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, and the like.
Gelatin, casein, arabic gum, completely (partially) saponified polyvinyl alcohol, silicon-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, diisobutylene / maleic anhydride copolymer salt, styrene / maleic anhydride Aqueous resins such as polymer salts, ethylene / acrylic acid copolymer salts, styrene / butadiene-based latex, acrylic-based latex, and urethane-based latex are exemplified.
The amount of the aqueous resin used is 30 to 95 based on the solid content of the protective layer.
Part weight% is preferred.

Examples of the auxiliary agent include surfactants such as sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium salt of lauryl alcohol sulfate, alginates, metal salts of fatty acids, zinc stearate, and stearate. Calcium phosphate, carnauba wax, paraffin wax, ester wax,
Lubricants such as stearyl phosphate, kaolin, clay, talc, calcium carbonate, aluminum hydroxide,
Pigments such as calcined clay, titanium oxide, diatomaceous earth, amorphous silica, glyoxal, crosslinkers such as polyamidoamine / epichlorohydrin resin, melamine resin, boric acid, borax, coloring dyes and fluorescent dyes. Can be

The adhesive layer is coated with an aqueous or organic solvent-based adhesive liquid containing an acrylic resin-based, synthetic rubber-based, or natural rubber-based adhesive as a main component.
Or provided by coating and drying so as to to 5 g / m ^2, or coated surface was coated to a 0.5～5.0M ² an adhesive layer coating solution mainly composed of electron beam-curable compound When,
It is obtained by bringing the thermosensitive recording layer surface or the intermediate layer surface formed on a smooth surface into close contact, and then irradiating an electron beam to cure the electron beam curable compound. A coating liquid for an adhesive layer containing an electron beam curable compound as a main component is preferable because it is more uniformly adhered.

It is preferable to include a pigment in the adhesive layer since the recording image quality can be further improved. The average particle diameter of the primary particles of the contained pigment is preferably about 0.2 to 3.0 μm. When the average particle diameter is less than 0.2 μm, the effect of improving the recording image quality is low. There is a possibility that the transferability to the adhesive layer and the recorded image quality may deteriorate.

The shape of the pigment contained in the adhesive layer may be spherical, needle-like, plate-like, column-like, or amorphous. Specific examples of such pigments include kaolin, clay, talc, calcium carbonate, aluminum hydroxide, calcined clay, titanium oxide, diatomaceous earth, silica, barium sulfate and the like. The amount of the pigment in the adhesive layer is preferably about 2 to 30% by weight based on the adhesive layer.

The electron beam curable compound contained in the adhesive layer coating liquid is, for example, a monomer or prepolymer having at least one ethylenically unsaturated bond. Examples of such a monomer include N-vinylpyrrolidone, acrylonitrile, styrene, acrylamide, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, tetrahydrofurfuryl acrylate, and phenoxyethyl. Acrylate, nonylphenoxyethyl acrylate, acrylate of caprolactone adduct, butoxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl acrylate, cyclohexyl (meth) acrylate, N, N-
Monofunctional monomers such as (meth) acrylates such as dimethylamino (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, 3-phenoxypropyl acrylate, and 2-methoxyethyl (meth) acrylate;

Hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate, tetraethylene glycol diacrylate, tricyclodecane dimethylol diacrylate, trimethylol propane triacrylate, dipentaerythritol hexa (penta And bifunctional monomers such as acrylate, acrylate of ε-caprolactone-modified dipentaerythritol, and diacrylate of ethylene oxide-modified bisphenol A.

The prepolymer includes a prepolymer composed of the above monomers. Such monomers and prepolymers may be used as a mixture of two or more kinds.

The coating solution for the adhesive layer containing the electron beam-curable compound is prepared, for example, by using a three-roll mill, a sand mill, a paint conditioner, an ultrasonic disperser, or the like to prepare a composition comprising an electron beam-curable compound and a pigment. Is done.

The electron beam accelerator used for the electron beam irradiation is not particularly limited, and for example, an electron beam irradiation device such as an electro-curtain system or a scanning system can be used. Among them, an electro-curtain type which is relatively inexpensive and can obtain a large output is effectively used. The acceleration voltage during electron beam irradiation is 30 to 30
It is about 0 KV.

As the support, for example, a polyolefin resin and a white inorganic pigment are heated and kneaded, and extruded from a die.
Synthetic paper manufactured by laminating a film composed of a polyolefin resin and a white inorganic pigment on both sides of one or two layers per side on one side of the one stretched in the longitudinal direction, and stretching in the transverse direction to be translucent or opaque, and polyethylene, A film obtained by heating and kneading a thermoplastic resin such as polypropylene, polystyrene, or polyester alone or a mixture, extruding from a die and biaxially stretching, and an opaque film that is biaxially stretched by mixing a white inorganic pigment with these resins. And those manufactured from pulp fibers such as high quality paper, medium quality paper, neutral paper, recycled paper, and coated paper. The basis weight of the support is about ²⁰ to 250 g / m ² .

Examples of the thermal recording method having an electron donating compound and an electron accepting compound include, for example, a combination of a leuco dye and a color former, a combination of a diazonium salt and a coupler, a chelate compound and a transition element such as iron, cobalt or copper. And a combination of an imino compound and an aromatic isocyanate compound. Of these, a combination of a leuco dye and a color former is preferably used because of its excellent color density. Less than,
A heat-sensitive recording material comprising a combination of a leuco dye which is an electron donating compound and a color former which is an electron accepting compound will be described in detail.

The leuco dye contained in the heat-sensitive recording layer is not particularly limited, and for example, various known dyes can be used. Specific examples of such leuco dyes include, for example, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3-diethylamino-7-anilinofluoran 3-cyclohexylamino-6-chlorofluoran 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-7-chlorofluorane, rhodamine (o-chloroanilino) lactam,
3-diethylamino-6,8-dimethylfluoran, 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-chloroanilino) fluoran, 3-di (n-butyl) amino-7- (o-fluoroanilino) fluoran, 3- ( N-ethyl-p-toluidino) -6-methyl-7-anilinofluoran, 3-
(N-ethyl-N-tetrahydrofurfurylamino)-
6-methyl-7-anilinofluoran, 3,3-bis [1- (4-methoxyphenyl) -1- (4-dimethylaminophenyl) ethylene-2-yl] -4,5,6
7-tetrachlorophthalide, 3-p- (p-dimethylaminoanilino) anilino-6-methyl-7-chlorofluoran, 3-p- (p-chloroanilino) anilino-6
-Methyl-7-chlorofluorane, 3,6-bis (dimethylamino) fluorene-9-spiro-3 '-(6'-
Demethylamino) phthalide and the like.

Specific examples of the coloring agent include, for example, 4,4 ′
-Isopropylidene diphenol, 1,1-bis (4-
(Hydroxyphenyl) cyclohexane, benzyl 4-hydroxybenzoate, 4,4′-dihydroxydiphenylsulfone, 2,4′-dihydroxydiphenylsulfone, 4-hydroxy-4′-isopropoxydiphenylsulfone, bis (3-allyl-4- (Hydroxyphenyl) sulfone, 4-hydroxy-4′-methyldiphenyl sulfone, 4-hydroxyphenyl-4′-benzyloxyphenyl sulfone, 3,4-dihydroxyphenyl-4′-methylphenyl sulfone, 2,4-bis (phenyl Phenolic compounds such as sulfonyl) phenol; thiourea compounds such as N, N'-di-m-chlorophenylthiourea Np-tolulsulfonyl-N'-3-
(P-tolulsulfonyloxy) phenylurea, p-
Tolylsulfonyl-p-aminophenol, N- (p-
Tolylsulfonyl) -N '- (p-tolyl) having a -SO ₂ NH- bond in the molecule, such as urea, p- chlorobenzoic acid zinc, 4- [2-(p-methoxyphenoxy)
Ethyloxy] zinc salicylate, 4- [3- (p-tolylsulfonyl) propyloxy] zinc salicylate, 5-
[P- (2-p-methoxyphenoxyethoxy) cumyl] Zinc salts of aromatic carboxylic acids such as zinc salicylate.

In the present invention, the ratio of the leuco dye to the color former in the heat-sensitive recording layer is appropriately selected according to the type of the leuco dye and the color former, and is not particularly limited. Generally, it is preferable to use 1 to 10 parts by weight, preferably about 1 to 5 parts by weight of a coloring agent per 1 part by weight of the leuco dye.

If necessary, the following sensitizers and storage improvers can be added to the heat-sensitive recording layer. Specific examples of the sensitizer include, for example, stearamide, behenamide, dibenzyl terephthalate, dibenzyl oxalate, di-p-methylbenzyl oxalate, di-p-chlorobenzyl oxalate, Dibutyl isophthalate, 2-naphthylbenzyl ether, 1,2-di (3-methylphenoxy) ethane, 1,2-diphenoxyethane, 1-phenoxy-
2- (β-naphthoxy) ethane, diphenyl carbonate, p-
Benzylbiphenyl and the like.

As the preservability improver, for example, 2,2'-
Methylene bis (4-methyl-6-tert-butylphenol), 4,4′-butyldenbis (6-tert-butylphenol)
Butyl-m-cresol), 1,1,3-tris (2-
Methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 2,
2′-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-thiobis (2-methyl-6
-Tert-butylphenol) and ultraviolet absorbers such as 2- (2'-hydroxy-5'-methylphenyl) -benzotriazole and 2-hydroxy-4-octyloxybenzophenone. In general, it is preferable that the sensitizer and the storage stability improver are each contained in an amount of about 0.1 to 4 parts by weight based on 1 part by weight of the leuco dye.

The heat-sensitive recording layer is formed, for example, by using water as a dispersion medium.
Leuco dye, color former and, if necessary, sensitizer by pulverizer such as sand mill, attritor and ball mill,
Having an average particle size of 2 together or separately with a preservability improver, etc.
After the pulverization is performed so as to have a particle size of not more than μm, the coating amount for the heat-sensitive recording layer prepared by adding an adhesive and the following auxiliaries onto the support is about 3 to 20 g / m ^2. , Formed by coating and drying.

As the adhesive contained in the heat-sensitive recording layer coating solution, for example, an aqueous resin contained in the above-mentioned protective layer coating solution is used. The amount of the adhesive used is preferably about 8 to 35 parts by weight based on the solid content of the heat-sensitive recording layer. Further, as the auxiliary agent, for example, the auxiliary agent contained in the above-mentioned coating liquid for a protective layer can be used.

An intermediate layer containing an aqueous resin is formed in order to prevent background fog of the heat-sensitive recording layer and to enhance the preservability of the recording portion. The aqueous resin is contained in the aqueous resin contained in the protective layer. Can be appropriately selected and used.
Among these, complete (partial) saponified polyvinyl alcohol, silicon-modified polyvinyl alcohol, which is excellent in film formability,
Acetoacetyl group-modified polyvinyl alcohol, carboxyl-modified polyvinyl alcohol and casein are preferred.

The intermediate layer is preferably formed by applying and drying a coating liquid in which an aqueous resin is dissolved or dispersed so that the coating amount after drying is about 1 to 5 g / m ² . Further, the coating liquid may contain an auxiliary agent that can be added to the protective layer coating liquid if necessary.

Each coating solution for forming each layer is applied by various known coaters such as a curtain coater, a gravure coater, a blade coater, a lip coater and a bar coater.

Further, in order to improve the recording sensitivity and recording image quality, an undercoat layer containing an oil-absorbing pigment or organic hollow particles as a main component is provided between the support and the heat-sensitive recording layer, and a protective layer is provided on the back side of the support. It is also possible to provide an adhesive layer, a magnetic recording layer and the like. Various other known techniques in the field of heat-sensitive recording medium production can be added as needed.

[0041]

The present invention will be described in detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. Unless otherwise specified, parts and% in the examples are parts by weight and% by weight, respectively.
To represent.

Example 1 Solution A Preparation A composition comprising 20 parts of 3-di (n-butyl) amino-6-methyl-7-anilinofluoran, 5 parts of a 10% aqueous solution of polyvinyl alcohol, and 20 parts of water. The product is dispersed with an Ultra Viscomil so that the average particle size becomes 1.3 μm.
A liquid was obtained.

Preparation of Solution B A composition comprising 50 parts of 4-hydroxy-4'-isopropoxydiphenylsulfone, 5 parts of a 10% aqueous solution of polyvinyl alcohol, and 70 parts of water was adjusted to an average particle diameter of 1.3 μm with an ultrabiscomil. To obtain a liquid B.

Preparation of coating solution for heat-sensitive recording layer 30 parts of solution A, 90 parts of solution B, 52 parts of 60% slurry of calcium carbonate, 40% aqueous solution of polyvinyl alcohol 40
Part, styrene-butadiene latex (trade name: L-
1537, solid concentration 50%, manufactured by Asahi Kasei Corporation) 28 parts,
Stearamide (trade name: High Micron G-27)
0, a solid concentration of 20%, manufactured by Chukyo Yushi Co., Ltd.), 11 parts of zinc stearate (trade name: Hydrin Z-7-30, a solid concentration of 30%, manufactured by Chukyo Yushi Co., Ltd.), and 82 parts of water. The mixture was stirred to obtain a coating liquid for a heat-sensitive recording layer.

Preparation of coating solution for intermediate layer Kaolin (trade name: UW-90, manufactured by Engelhard Co.)
Of a 60% slurry, 180 parts of a 10% aqueous solution of silicon-modified polyvinyl alcohol (trade name: R-1130, manufactured by Kuraray Co., Ltd.) and 150 parts of water are mixed and stirred to obtain a coating liquid for an intermediate layer. Was.

Preparation of Coating Solution for Adhesive Layer 100 parts of acrylate of ε-caprolactone-modified dipentaerythritol (trade name: Kayarad DPCA-60, manufactured by Nippon Kayaku Co., Ltd.) as an electron beam-curable compound, average particle size: 1. 10 parts of 5 μm spherical silica was dispersed by a three-roll mill to obtain a coating liquid for an adhesive layer.

Preparation of coating liquid for protective layer Acrylic resin emulsion (trade name: VARISTAR B-
1000, solid concentration 20%, manufactured by Mitsui Chemicals, Inc.) 250 parts,
Kaolin with an average particle size of 0.8 μm (trade name: UW-9)
0, 75 parts of a 60% slurry of Engelhard Co., Ltd., potassium stearyl phosphate (trade name: Woopol 1800, solid concentration 35%, manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.) 10
Part, 5 parts of 25% aqueous solution of polyamidoamine / epichlorohydrin, 5 parts of sodium salt of dioctylsulfosuccinic acid
% Aqueous solution and 100 parts of water were mixed and stirred to obtain a coating liquid for a protective layer.

Preparation of Thermosensitive Recording Material On one surface of a synthetic paper (trade name: Yupo FPG-80, manufactured by Oji Yuka Synthetic Paper) as a support, a coating solution for a thermosensitive recording layer and a coating solution for an intermediate layer were applied. The coating amount after drying was 8.0 g /
m ² , 3.0 g / m ² , followed by coating in a bar coating method and drying to form a heat-sensitive recording layer and an intermediate layer, followed by a super calender treatment, and further a coating for an adhesive layer. The solution was applied so that the applied amount was 3.0 g / m ² to form an adhesive layer applied surface. Separately, as a substrate having a smooth surface, a thickness of 40 μm having a root mean square roughness of 0.11 μm is used.
m on an anchor coat layer of a PET film (corona discharge treatment immediately before applying the protective layer coating liquid) so that the coating amount after drying the protective layer coating liquid is 1.0 g / m ^2. After applying and drying with a coating method, it is super-calendered,
The surface of the adhesive layer and the surface of the protective layer are brought into close contact with each other, and an electron curtain type electron beam accelerator (ESI
175KV, absorbed dose 4.0Mr
After curing the adhesive layer by irradiating an electron beam of ad,
The heat-sensitive recording medium was obtained by peeling off between the T film and the protective layer.

Example 2 The procedure of Example 1 was repeated except that the thermosensitive recording medium was prepared as follows.
A thermosensitive recording medium was obtained in the same manner as in Example 1.

Preparation of Thermosensitive Recording Material A coating solution for a thermosensitive recording layer and a coating solution for an intermediate layer were respectively dried on one side of synthetic paper (trade name: YUPO FPG-80, manufactured by Oji Oil Chemical Synthetic Paper Co., Ltd.). The coating amount is 8.0 g / m ² , 3.0
g / m ² by bar coating method to form a heat-sensitive recording layer and an intermediate layer, and then perform a super calendering process. Thickness 40 μm with roughness 0.11 μm
Bar coating on the anchor coat layer of a PET film (with a corona discharge treatment immediately before coating the protective layer coating liquid) so that the coating amount after drying the protective layer coating liquid is 1.0 g / m ^2. After applying and drying by a working method, the composition was subjected to a super calender treatment, and further applied thereon so that the coating amount of the adhesive layer coating liquid was 3.0 g / m ² to form an adhesive layer coated surface. Next, the surface on which the adhesive layer is applied and the above-mentioned intermediate layer are brought into close contact with each other, and PET is applied.
From the film side, an electron curtain type electron beam accelerator (E
Acceleration voltage 175 KV, absorbed dose 4.0
After irradiating Mrad electron beam to cure the adhesive layer,
The heat-sensitive recording medium was obtained by peeling off between the PET film and the outermost layer.

Example 3 The procedure of Example 1 was repeated except that the thermosensitive recording medium was prepared as follows.
A thermosensitive recording medium was obtained in the same manner as in Example 1.

Preparation of Thermosensitive Recording Material PE having a root mean square roughness of 0.08 μm and a thickness of 20 μm
On a T film (with a corona discharge treatment immediately before applying the coating liquid for the protective layer and applying the coating liquid for the protective layer), apply the coating liquid for the protective layer, the coating liquid for the heat-sensitive recording layer, and the coating liquid for the intermediate layer after drying. There are ^{3.0g / m 2, 8.0g / m} 2, 3.0g / m 2
After coating and drying in order by a bar coating method, a super calender treatment was performed. Separately, synthetic paper (trade name:
One side of YUPO FPG-80, manufactured by Oji Yuka Synthetic Paper Co., Ltd.) was coated with an adhesive layer coating solution such that the coating amount was 3.0 g / m ² to form an adhesive layer coated surface. Further, the adhesive layer layer-coated surface and the intermediate layer are brought into close contact with each other, and an electron beam having an acceleration voltage of 175 KV and an absorbed dose of 4.0 Mrad is irradiated from the PET film side by an electron curtain type electron beam accelerator (manufactured by ESI). After curing, the PET film and the protective layer were peeled off to obtain a thermosensitive recording medium.

Example 4 The procedure of Example 1 was repeated except that the thermosensitive recording medium was prepared as follows.
A thermosensitive recording medium was obtained in the same manner as in Example 1.

Preparation of thermosensitive recording medium PE having a thickness of 40 μm and a root mean square roughness of 0.11 μm
The coating amount of the protective layer coating solution and the thermosensitive recording layer coating solution was 3.0 g each on the anchor coat layer of the T film (corona discharge treatment was performed immediately before the application of the protective layer coating solution).
/ M ² , 8.0 g / m ² , followed by a bar coating method, followed by a super calender treatment, and then a coating amount of the adhesive layer coating liquid on the heat-sensitive recording layer was 3.0 g / m ^2. m ² to form an adhesive layer coated surface. Further, the surface coated with an adhesive layer and a synthetic paper (trade name: YUPO FPG-80,
(Oji Yuka Synthetic Paper Co., Ltd.) and an electro-curtain type electron beam accelerator (ESI) from the PET film side.
After irradiation with an electron beam having an acceleration voltage of 175 KV and an absorbed dose of 4.0 Mrad to cure the adhesive layer, the PET film and the protective layer were peeled off to obtain a thermosensitive recording medium.

Example 5 The following coating liquid for a protective layer was used in place of the coating liquid for a protective layer used in Example 1, and a thermosensitive recording medium was prepared as follows in the preparation of a thermosensitive recording medium. Except for the above, a thermosensitive recording medium was obtained in the same manner as in Example 1.

Preparation of Coating Liquid for Protective Layer 100 parts of acrylate of ε-caprolactone-modified dipentaerythritol (trade name: Kayarad DPCA-60, manufactured by Nippon Kayaku Co., Ltd.) as an electron beam-curable compound, average particle diameter 1.5 μm 10 parts of silica, 1 part of zinc stearate,
Five parts of potassium stearyl phosphate were dispersed in a three-roll mill to obtain a coating liquid for a protective layer.

Preparation of thermosensitive recording medium One side of a synthetic paper (trade name: YUPO FPG-80, manufactured by Oji Yuka Synthetic Paper Co., Ltd.) was dried with a coating solution for the thermosensitive recording layer and a coating solution for the intermediate layer, respectively. The coating amount is 8.0 g / m ² , 3.0
g / m ² , by applying a bar coating method sequentially to form a heat-sensitive recording layer and an intermediate layer. After performing a super calender treatment, a coating amount of a protective layer coating liquid is applied on the intermediate layer. 0.0 g / m ² to form a protective layer coating surface, and a thickness of 40 μm having a root mean square roughness of 0.11 μm.
The anchor coat layer of the PET film (with corona discharge treatment immediately before the coating liquid for the protective layer is applied) and the surface coated with the protective layer are brought into close contact with each other, and accelerated from the PET film side by an electron curtain type electron beam accelerator (manufactured by ESI). Voltage 175K
V, the protective layer was cured by irradiating an electron beam with an absorption dose of 4.0 Mrad, and then the PET film and the protective layer were peeled off to obtain a thermosensitive recording medium.

Example 6 A thermosensitive recording medium was obtained in the same manner as in Example 5, except that the thermosensitive recording medium was prepared as described below.

Preparation of Thermosensitive Recording Material One side of a synthetic paper (trade name: YUPO FPG-80, manufactured by Oji Yuka Synthetic Paper Co., Ltd.) was dried with a coating solution for the thermosensitive recording layer and a coating solution for the intermediate layer, respectively. The coating amount is 8.0 g / m ² , 3.0
g / m ² by bar coating method to form a heat-sensitive recording layer and an intermediate layer, and after super calendering, the root mean square roughness is 0.11.
The coating amount of the protective layer coating solution was 2.0 g / m ² on the anchor coat layer of a PET film having a thickness of 40 μm and having a thickness of 40 μm (corona discharge treatment was performed immediately before the coating solution for the protective layer was applied). It was applied to form a protective layer application surface. The intermediate layer surface on the support side and the protective layer coating surface are brought into close contact with each other, and an acceleration voltage of 175 KV and an absorbed dose of 4.0 Mra are applied from the PET film side by an electro-curtain type electron beam accelerator (manufactured by ESI).
After irradiating the protective layer with the electron beam of d, the PET film and the protective layer were peeled off to obtain a thermosensitive recording medium.

Example 7 A thermosensitive recording medium was obtained in the same manner as in Example 1 except that spherical silica was not used in the preparation of the coating solution for the adhesive layer in Example 1.

[Embodiment 8] In the production of the thermosensitive recording medium of the embodiment 1, the thickness 40 having a root mean square roughness of 0.11 μm was used.
The root mean square roughness is 0.1 in place of a μm PET film.
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that a PET film having a thickness of 40 μm, which was 8 μm, was used.

Example 9 In the production of the thermosensitive recording medium of Example 1, the thickness 40 having a root-mean-square roughness of 0.11 μm was used.
The root mean square roughness is 0.1 in place of a μm PET film.
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that a 4 μm thick PET film having a thickness of 100 μm was used.

[Comparative Example 1] In the production of the thermosensitive recording medium of Example 1, the thickness 40 having a root-mean-square roughness of 0.11 μm was used.
Mean square roughness is 0.2 in place of μm PET film
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that a 4 μm thick PET film having a thickness of 40 μm was used.

[Comparative Example 2] In the production of the thermosensitive recording medium of Example 1, the thickness 40 having a root-mean-square roughness of 0.11 μm was used.
The mean square roughness is 0.0 in place of the μm PET film.
A thermosensitive recording medium was obtained in the same manner as in Example 1, except that a PET film having no anchor coat layer having a thickness of 40 μm and a thickness of 2 μm was used.

Comparative Example 3 In the preparation of the coating solution for the protective layer of Example 1, kaolin (trade name: UW-90, manufactured by Engelhard Co.) was used instead of 75 parts of a 60% slurry. -90, manufactured by Engelhard Co.)
% Slurry, 50 parts of a 50% slurry of calcium carbonate having an average particle diameter of 2.1 μm, and 50 parts of water were used in the same manner as in Example 1 to obtain a thermosensitive recording medium.

Comparative Example 4 A thermosensitive recording medium was prepared in the same manner as in Example 3 except that the coating liquid for a protective layer used in Comparative Example 3 was used instead of the coating liquid for a protective layer used in Example 3. I got

The following evaluation tests were carried out on each of the thus obtained heat-sensitive recording materials and those obtained in the course of production. The results are shown in Table 1.

[Gloss] Gloss meter (trade name: GM-26)
D, unrecorded area, thermal head (resistance value: 520Ω, 8 dots / mm, 0.15) using Murakami Color Research Laboratory
mm ² / dot, applied pulse width 2m sec, by applying pulse period 5m sec) 30mJ / mm ² (low energy) and 80 mJ / mm ² (high energy) recording unit of gloss recorded in energy (in 1993 (Based on specified JIS P8142-1993) at incident angles of 20 degrees and 75 degrees.

[Smoothness] The smoothness of each surface was measured using a smoothness meter (trade name: Digital Oken type smoothness meter, manufactured by ASAHI SEIKO).

[Root Mean Square Roughness] The root mean square roughness (based on JIS B 0601-1982) of each surface was measured with an optical interference microscope (trade name: ZYGO, magnification 200 times, rms arithmetic expression, manufactured by Canon Inc.). It was measured.

[Recording image quality] The obtained heat-sensitive recording medium was subjected to halftone printing using a built-in pattern of a printer (trade name: UP-880, manufactured by Sony Corporation), and the obtained image quality of the recording portion was visually judged as follows. did. ☆: The image quality of the recording unit is very uniform. A: The image quality of the recording unit is uniform. ：: The image quality of the recording unit is slightly uneven. Δ: The image quality of the recording portion is slightly nonuniform, and there are slight white spots. X: The image quality of the recording unit is not uniform.

[0072]

[Table 1]

[0073]

As is clear from the results shown in Table 1, the heat-sensitive recording material of the present invention has excellent effects on the surface gloss of the recording portion from low energy to high energy, and excellent recording image quality.

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[Procedure amendment]

[Submission date] March 9, 2001 (2001.3.9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Change

[Correction contents]

[Gloss] Gloss meter (trade name: GM-26)
D, Murakami Color Research Laboratory), an unrecorded portion , and a thermal head (resistance 520 Ω, 8 dots / mm, 0.
015 mm ² / dot, applied pulse width 2 msec, applied pulse cycle 5 msec), and 30 mJ / mm.
² (low energy) and 80 mJ / mm ² (high energy), the glossiness ( JI)
SP 8142-1993 ) at angles of incidence of 20 degrees and 75
Measured in degrees.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0070

[Correction method] Change

[Correction contents]

[ Root- mean- square roughness] The root- mean- square roughness of each surface (based on JIS B 0601-1982) was measured using a light wave interference microscope (trade name: ZYGO, magnification 200 times, r
ms calculation formula, manufactured by Canon Inc.).

Claims (4)

[Claims] 1. A thermosensitive recording medium having at least a thermosensitive recording layer containing an electron donating compound and an electron accepting compound on one surface of a support, wherein the outermost layer on the thermosensitive recording layer side has a smooth surface. The glossiness of the recording portion (JIS) which is a layer transferred from the recording material and recorded from the heat-sensitive recording layer side with an energy of 80 mJ / mm ² by a thermal head.
30% at 20 °, 7%
85% or more at 5 °. 2. The glossiness (JI) of an unrecorded portion on the heat-sensitive recording layer side.
2. The heat-sensitive recording material according to claim 1, wherein the thermosensitive recording medium (based on SP8142-1993) is at least 30% at 20 ° and at least 85% at 75 °. 3. The heat-sensitive recording material according to claim 1, wherein the outermost layer is a protective layer containing an aqueous resin. 4. A root-mean-square roughness (based on JIS B 0601-1982) of a substrate having a smooth surface measured by a light wave interference microscope (according to JIS B 0651-1973). Claim 1, wherein the thickness is 0.50 µm.
4. The heat-sensitive recording material according to 2 or 3.