JPH07237351A - Thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a thermal recording material excellent in glossiness and the uniformity of an image, high in the adhesive strength of a gloss layer and having high stickiness. CONSTITUTION:In a thermal recording material having such a structure that a thermal color forming layer, an intermediate layer and a gloss layer are successively provided on at least the single surface of a support, the intermediate layer contains acryl modified polyvinyl alcohol and the gloss layer contains an acrylic ionizing radiation curable resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal recording material, and more specifically to a thermal recording material suitable for use in an image thermal printer which outputs a CRT image for medical measurement as a hard copy. It is a thing.

[0002]

2. Description of the Related Art A thermal recording material is generally composed of paper, synthetic paper, plastic film or the like on at least one surface thereof, and a colorless or pale color-forming substance such as an electron-donating leuco dye and an electron-accepting material. A thermosensitive coloring layer containing an organic acidic developer such as a phenolic compound and an adhesive as main components, and these coloring dyes and the developer react with heat energy to develop a color. A recorded image can be obtained. Such a thermal recording material,
The recording device has advantages such as compact size, low cost, and easy maintenance, and is not only used as a recording medium for facsimiles, automatic ticket vending machines, and scientific measuring machines, but also P
It is widely used as an output medium for various printers and plotters for OS labels, CAD and CRT medical images.

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 fine line recording require synthetic paper having a multilayer structure, and 2 containing inorganic pigment accordingly
An axially stretched thermoplastic resin film is used. In particular, as an image printer sheet for CRT medical measurement, a recording sheet having high whiteness and high gloss is desired. The conventional recording paper has low gloss and insufficient contrast. The glossiness of the thermosensitive recording medium is, for example, JIS P 8142 in order to obtain a satisfactory contrast.
It is necessary to set the glossiness to 70% or more according to the above. For that purpose, the smoothness of the thermosensitive coloring layer and / or the intermediate layer is increased, and a gloss layer made of an ultraviolet curable resin or an electron beam curable resin is provided in the intermediate layer (JP-A-54-354).
No. 9, JP-A-59-26291, JP-A-58.
No. 177392 and Japanese Patent Laid-Open No. 62-279980), the higher the smoothness of the gloss layer, the better the adhesion to the recording head and the higher the paper feed resistance, resulting in a shorter print size. There is a stick problem such as horizontal stripe-shaped recording unevenness. Further, when the smoothness of the intermediate layer is increased, there is a problem that the adhesive strength of the gloss layer is lowered. In order to improve the adhesive strength and the stick, if a pigment having a large particle size is added to the intermediate layer or the gloss layer to reduce the smoothness, the stick is improved, but there is a problem that the uniformity of the image is deteriorated.

[0004]

The present invention has a gloss of 70.
%, The heat-sensitive recording material provided with a glossy layer containing an ionizing radiation curable resin as the glossy layer resin has a high adhesion strength of the glossy layer, and a stick,
The present invention provides a thermosensitive recording medium having good image uniformity.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have diligently studied to improve the adhesive strength of the glossy layer and to improve the stick and image uniformity in a thermal recording material provided with a glossy layer made of an ionizing radiation curable resin. As a result of further study, the present invention has been completed.

That is, according to the present invention, a thermosensitive coloring layer containing a colorless or pale-colored electron-donating leuco dye, an organic acidic substance that develops the leuco dye by heating and an adhesive as main components, on at least one surface of a support, In a thermosensitive recording medium in which an intermediate layer made of a water-based paint is further provided on the thermosensitive coloring layer, and a gloss layer containing an ionizing radiation curable resin is further provided on the intermediate layer, an acrylic-modified polyvinyl is used as a resin for forming the intermediate layer. A heat-sensitive recording material comprising an alcohol and an acrylic resin as an ionizing radiation curable resin for the glossy layer.

By containing acrylic modified polyvinyl alcohol as the resin forming the intermediate layer and using the acrylic resin as the gloss layer resin, the adhesive strength is high and the image uniformity is good even if the smoothness is low. Although the cause is not clear, it is presumed that the compatibility between the intermediate layer and the gloss layer is good and they are integrated, so the adhesive strength increases, and even if the intermediate layer has low smoothness, there is no difference in heat conductivity. It

In the present invention, the support is obtained by heat-kneading a polyolefin resin and a white inorganic pigment, extruding from a die, and stretching in the machine direction. Two
Synthetic paper produced by stacking layers and stretching in the transverse direction, and thermoplastic resin such as polyolefin-based resin and polyester-based resin, or a mixture obtained by extruding biaxially a mixture of thermoplastic resins from a die, and a white inorganic material for the thermoplastic resin. In addition to a biaxially stretched film obtained by extruding a pigment obtained by heating and kneading it from a die, a material produced from pulp fibers such as high-quality paper, medium-quality paper, roll paper, recycled paper and coated paper can be used. The support made of pulp fibers improves the uniformity of the image,
It is desirable to apply the heat-sensitive layer after providing the coating layer in advance.

The thermosensitive color developing layer of the present invention contains a colorless or light-colored electron-donating leuco dye, an organic acidic substance that develops the color of the leuco dye by heating, and an adhesive as main components, and if necessary, a white pigment. , A heat-fusible substance, an auxiliary additive component, for example, a dispersant, a defoaming agent, a fluorescent dye or the like may be contained.

The thermosensitive coloring layer of the present invention is applied to at least one surface of the above-mentioned support by a coating method such as an air knife method, a Meyer bar method, a blade method, a reverse roll method or a slit die method which has been conventionally used by those skilled in the art. And the coating amount after drying is ² to 10 g / m ² , and preferably 4 to 9 g / m ² . In addition, the surface of the heat-sensitive coloring layer is a super calendar, gloss calendar,
By performing the smoothing treatment with a machine calendar or the like, the coatability of the intermediate layer can be improved and the intermediate layer having a uniform thickness can be formed.

The color-forming dye used in the present invention is a colorless or light-colored electron-donating leuco dye capable of forming a color by reacting with a developer under heating. For example, 3-diethylamino-6-methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3-
(N-methyl-N-cyclohexyl) amino-6-methyl-7-anilinofluorane, 3-diethylamino-7
-Chloroanilinofluorane, 3- [N-ethyl-N-
(P-Methylphenyl) amino] -6-methyl-7-anilinofluorane, 3-diethylamino-7- (metatrifluoromethyl) anilinofluorane, 3- (N-ethyl-N-tetrahydrofurfuryl) Amino-6-methyl-7-anilinofluorane, 3- (N-ethyl-N-
Isopentyl) amino-6-methyl-7-anilinofluorane, 3- (N, Ndibutyl) amino-6-methyl-
It is composed of at least one member of a fluoran dye such as 7-anilinofluoran.

The color developer used in the present invention comprises an electron-accepting organic acidic substance capable of reacting with a color-forming dye under heating to develop a color. Such a color developer liquefies or vaporizes at room temperature or higher, preferably 70 ° C. or higher, and reacts with the color forming dye to develop a color. For example, 4,4′-isopropylidenediphenol (bisphenol A), 4,4′-isopropylidenebis (2-chlorophenol), 4,4′-isopropylidenebis (2-methylphenol), 4,4 ′
-Isopropylidene bis (2,6-t-butylphenol), 4,4'-sec-butylidene diphenol,
4,4'-cyclohexylidene diphenol, 4-t-
Butylphenol, 4-phenylphenol, 4-hydroxydiphenoxide,

4,4'-dihydroxydiphenyl sulfone, 2,4'-dihydroxydiphenyl sulfone, 3,
3'-dihydroxydiphenyl sulfone, 3,3'-diamino-4,4'-dihydroxy-diphenyl sulfone, 3,3'-diallyl-4,4'-dihydroxydiphenyl sulfone, 3,3'-dichloro-4,4 '-Dihydroxydiphenyl sulfone, 4-hydroxydiphenyl sulfone, 4-hydroxy-4'-isopropyloxydiphenyl sulfone, 4-hydroxy-4'-benzyloxydiphenyl sulfone, 2,4-dihydroxydiphenyl sulfone, 2,4-dihydroxy- It is composed of at least one member selected from 4′-methyldiphenyl sulfone, 3,4-dihydroxyphenyl-p-trisulfone and the like. Since the color developer usually has the highest color density, 1 to 5 parts by weight per 1 part by weight of the color forming dye,
It is preferably mixed and used in a ratio of 1.5 to 3 parts by weight.

In the invention, the adhesive contained in the thermosensitive coloring layer may be either a water-soluble resin or a water-dispersible resin. For example, polyvinyl alcohol, starch, modified starch, gum arabic, gelatin, casein, chitosan, methyl cellulose, hydroxyethyl cellulose, hydroxymethyl cellulose, polyvinylpyrrolidone, polyacrylic acid salt, polyacrylic amide, polyester resin, styrene-acrylic acid ester copolymer resin, Water-soluble resins such as styrene-maleic anhydride copolymer resin, methyl vinyl ether-maleic anhydride copolymer resin, isopropylene-maleic anhydride copolymer resin, and vinyl acetate emulsion, acrylic ester copolymer emulsion, methacrylic ester copolymer Polymerized emulsion, vinyl acetate- (meth) acrylic acid ester copolymer emulsion, polyurethane emulsion, polyvinyl chloride emulsion, polyvinylidene chloride emulsion ® down, SBR latex, minimum film forming temperature in emulsion, such as NBR latex can be used alone or as a mixture of 20 ° C. below the film forming properties of good water-dispersible resin.

However, it is necessary that the mixed liquid does not develop color, aggregate, or have a high viscosity when mixed with the respective dispersion liquids of the color forming dye and the color developer, and the formed heat-sensitive The recording layer film is tough,
It is necessary to have no desensitizing effect. The content of the adhesive in the heat-sensitive color developing layer is preferably 8 to 30%. If it is less than 8%, the coating film strength is low, and if it exceeds 30%, the sensitivity is lowered.

Further, in order to improve the water resistance of the thermosensitive coloring layer, a crosslinking agent for curing the resin can be used if necessary. For example, glyoxal, dialdehyde compounds such as dialdehyde starch, polyamine compounds such as polyethyleneimine, epoxy compounds, polyamide resins, melamine resins, diglycidyl compounds such as glycerin diglycidyl ether, dimethylol urea compounds, aziridine compounds, Blocked isocyanate compounds and inorganic compounds such as ammonium persulfate, ferric chloride, and magnesium chloride can be used in the range of 1% to 10%.

The pigment used in the thermosensitive coloring layer of the present invention is, for example, calcium carbonate, magnesium carbonate, magnesium oxide, kaolin, clay, talc, calcined clay, silica, diatomaceous earth, synthetic aluminum silicate, zinc oxide,
There are inorganic pigments such as titanium oxide, aluminum hydroxide, barium sulfate, surface-treated calcium carbonate and silica, and organic pigments such as urea resin, styrene-methacrylic acid copolymer and polystyrene resin. The pigment content of the heat-sensitive color forming layer is preferably 5 to 40% by weight, and when it exceeds 40% by weight, the recording density is lowered, and when it is less than 5% by weight, the stick tends to be deteriorated.

Examples of the heat-fusible substance used in the thermosensitive coloring layer of the present invention include fatty acid amides such as stearic acid amide, stearic acid ethylenebisamide, oleic acid amide, palmitic acid amide, coconut fatty acid amide and behenic acid amide. , Fatty acid metal salts such as zinc stearate and calcium stearate, hydrophobic waxes such as polyethylene wax, carnauba wax, paraffin wax and ester wax,

Oxalic acid di-p-methylbenzyl ester, oxalic acid di-p-chlorobenzyl ester, terephthalic acid dimethyl ester, terephthalic acid dibutyl ester, terephthalic acid dibenzyl ester, isophthalic acid dibutyl ester, 1-hydroxynaphthoic acid phenyl ester. Ester, 1,2-di (3-methylphenoxy) ethane,
1,2-diphenoxyethane, 1-phenoxy-2-
(4-methylphenoxy) ethane, diphenyl carbonate, p
-Benzylbiphenyl, 2,2'-methylenebis (4-
Methyl-6-t-butylphenol), 4,4'-butylidenebis (6-t-butyl-3-methylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) ) Butane, 2,2′-methylenebis (4-ethyl-6-t-butylphenol),
2,4-di-t-butyl-3-methylphenol, 4,
Hindered phenols such as 4′-thiobis (3-methyl-6-t-butylphenol), 2- (2′-hydroxy-5′-methylphenyl) -benzotriazole,
And sensitizers such as 2-hydroxy-4-benzyloxybenzophenone, antioxidants, and ultraviolet absorbers.
In general, the heat-fusible substance is preferably contained in the thermosensitive coloring layer in a ratio of 4 parts by weight or less with respect to 1 part by weight of the color developer.

Further, in order to improve the wetting of the heat-sensitive layer coating and eliminate repelling, a wetting improving agent such as acetylene glycol or dialkyl sulfosuccinate may be added. The intermediate layer provided on the heat-sensitive color developing layer of the present invention prevents penetration of the gloss layer resin to prevent background coloration of the heat-sensitive color developing layer due to the ionizing radiation-curable resin and to improve stickiness and glossiness. Is.

The intermediate layer of the present invention contains an acrylic-modified polyvinyl alcohol as a water-soluble resin and a pigment, and optionally contains a crosslinking agent and a lubricant. The intermediate layer of the present invention has a coating amount after drying of 1.0 to 10.0 g / m ² , preferably 2.0 to 7.
It can be obtained by coating with 0 g / m ² . The coating method can be appropriately selected and used from among the methods used for the thermosensitive coloring layer. If the coating amount of the intermediate layer is less than 1.0 g / m ² , the coating film is not formed uniformly, and there is a problem that the scratch resistance, water resistance, and chemical resistance decrease. Coating amount is 10.0
If it exceeds g / m ² , there is a drawback that the sensitivity is lowered and the recording density is lowered.

The acryl-modified polyvinyl alcohol used in the intermediate layer of the present invention is a graft copolymer of polyvinyl alcohol and acrylonitrile and / or methacrylonitrile, a homopolymer of acrylonitrile, a homopolymer of methacrylonitrile and polyvinyl alcohol. Although it is obtained as a mixture, it is desirable that the proportion of the graft copolymer is high. For this reason, it is desirable to use a persulfate such as ammonium persulfate or potassium persulfate as a polymerization initiator to enhance the grafting efficiency in carrying out the polymerization reaction. The reaction time usually requires 2 to 6 hours, and it is necessary to sufficiently reduce acrylonitrile and methacrylonitrile as residual monomers. The polyvinyl alcohol used as a raw material is not particularly limited, and a commercially available one having a saponification degree of 80 to 100% and a polymerization degree of 500 to 2,500 can be used. Considering the water resistance, the polymerization degree is preferably 1,000 or more.

Acrylonitrile and methacrylonitrile are used as monomers for graft copolymerization and can be used alone or in combination. As the polymerization initiator, hydrogen peroxide, tertiary butyl hydroperoxide, peroxides such as benzoyl peroxide, persulfates such as ammonium persulfate and potassium persulfate, azobisisobutyronitrile, 2-2′- An azo compound such as azobis (2-aminopropane) dihydrochloride can be used. Among them, water-soluble substances such as hydrogen peroxide and ammonium persulfate are preferable. It is also possible to use it in combination with a reducing agent as a redox polymerization system. Usually, the amount of the polymerization initiator used is preferably 0.1 to 10% by weight based on acrylonitrile and methacrylonitrile. The amount of acrylonitrile and methacrylonitrile used for radical polymerization based on 100 parts by weight of polyvinyl alcohol is preferably 2 to 25% by weight, and if less than 2% by weight, the water resistance is poor, and if more than 25% by weight, the viscosity of the graft copolymer is high. Therefore, there is a problem in the paint preparation and coating process of the intermediate layer paint.

In the intermediate layer of the present invention, a water-soluble resin and / or a water-dispersible resin other than the acrylic modified polyvinyl alcohol can be used within a range not impairing the uniformity of the image. The water-soluble resin and / or the water-dispersible resin can be appropriately selected and used from those used for the thermosensitive coloring layer. The resin content of the intermediate layer is 20 with respect to the solid content of the intermediate layer.
If it is less than 20% by weight, the barrier property of the intermediate layer is low, the background color is increased, and the glossiness is lowered. If the amount is more than 80% by weight, the adhesion of the ionizing radiation curable resin may be deteriorated or the stick may be deteriorated, which is a problem.

The pigment used in the intermediate layer of the present invention is effective not only for reducing the smoothness of the intermediate layer and improving the adhesiveness of the gloss layer, but also for improving stickiness, and is used for the thermosensitive coloring layer. The pigment can be appropriately selected and used. The pigment content is preferably 20 to 80% by weight based on the solid content of the intermediate layer. If it is less than 20% by weight, the adhesiveness of the ionizing radiation-curable resin will be deteriorated and the stick will be deteriorated, and if it exceeds 80% by weight, the barrier property will be deteriorated.

If desired, a crosslinking agent and a lubricant may be added to the intermediate layer of the present invention. The cross-linking agent can be appropriately selected and used from those used for the thermosensitive color developing layer. The compounding amount of the crosslinking agent is 30 with respect to the solid content of the intermediate layer.
It is preferably less than or equal to wt%. Lubricants used in the intermediate layer of the present invention include, for example, waxes such as zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax and ester wax, lauryl phosphate ester, oleyl phosphate ester, stearyl phosphate ester and the like. Alkylsulphonic acid esters and their alkali metal salts, lauryl sulfonic acid esters, oleyl sulfonic acid esters, stearyl sulfonic acid esters and other alkyl sulfonic acid esters and their alkali metal salts, glyceryl monomyristate, glyceryl monostearate, glyceryl monooleate , Glyceryl fatty acid ester such as glyceryl distearate, glyceryl dioleate, diglyceryl monolaurate, diglyceryl dilaurate, teremonolaurate Raguriseriru, monolauryl hexaglyceryl, there are polyglycerol fatty acid esters such as monolaurate decaglyceryl, desensitizing effect from them decoloring action, it is necessary to select a without background color effects. It is desirable to add the lubricant in an amount of 10% or less based on the solid content of the intermediate layer.

After coating the intermediate layer, a back layer is coated if necessary from the viewpoints of curl prevention and antistatic property, and further subjected to smoothing treatment with a super calender, gloss calender, machine calender or the like to obtain an image. Uniformity of
The sensitivity and recording density can be improved.

The gloss layer of the present invention comprises α rays, β rays, γ rays and X rays.
It contains an acrylic ionizing radiation curable resin having at least one double bond that can undergo a curing reaction upon irradiation with ionizing radiation such as rays, neutron rays, ultraviolet rays, and electron beams, and a pigment is added if necessary. The coating amount after curing the coating composition on the intermediate layer is 0.5 to 5.0 g / m ² , preferably 0.8 to 5.0 g / m ² .
It can be obtained by coating the coating solution to 3.0 g / m ² and then curing it with ionizing radiation. Coating amount is 0.8
If it is less than g / m ² , the glossiness is low, and if it exceeds 5.0 g / m ² , the recording sensitivity is lowered, which is a problem.

The ionizing radiation-curable resin used in the gloss layer of the present invention is made of an acrylic prepolymer or monomer having an ethylenically unsaturated bond.
(A) Aliphatic, alicyclic, araliphatic polyhydric alcohol having 2 to 6 valences and poly (meth) acrylate of polyalkylene glycol, (b) aliphatic, alicyclic, araliphatic 2 to 6
Poly (meth) acrylate of polyhydric alcohol in the form of addition of alkylene oxide to divalent polyhydric alcohol,
(C) Poly (meth) acryloyloxyalkyl phosphate ester, (d) Polyester poly (meth) acrylate, (e) Epoxy poly (meth) acrylate, (f)
Polyurethane poly (meth) acrylate, (g) polyamide poly (meth) acrylate, (h) polysiloxane poly (meth) acrylate, (i) side chain and / or vinyl type or diene having (meth) acryloyloxy group at the terminal. Examples include low polymers, (j) prepolymers such as modified oligoester (meth) acrylates described in (a) to (i) above. As the monomer, (k) an ethylenically unsaturated (meth) acrylamide or an alkyl-substituted (meth) acrylamide, (l) an amino group-containing monomer such as dimethylaminoethyl (meth) acrylate-2-vinylpyridine, ( m) nitrile group-containing monomer such as (meth) acrylonitrile, (n) mono (meth) acrylate of alkylene oxide addition polymer of compound containing active hydrogen, (o) alkylene oxide of compound containing active hydrogen A bifunctional monomer comprising a diester of an addition polymer and (meth) acrylic acid, (p) bisacrylamide such as N, N-methylenebisacrylamide, (q) an alkylene oxide addition polymer of a compound containing active hydrogen, Examples thereof include polyfunctional monomers made of polyester with (meth) acrylic acid.

If necessary, an inorganic pigment or an organic pigment may be added to the gloss layer of the present invention. Although the pigment may be effective in improving stickiness, it tends to cause a decrease in glossiness, and in order to suppress the decrease in glossiness, a pigment having an average particle size of 1.0 μm or more and a relatively large particle size is used in the gloss layer. It is desirable to add 30% by weight or less to the solid content. If the amount is more than 30% by weight, the gloss is lowered, which is a problem. Of the ionizing radiation, α rays, β rays, γ rays, and X rays are dangerous to the human body, and therefore electron beams and ultraviolet rays, which are less dangerous, are used.

When an electron beam is used, the electron dose for irradiation is preferably in the range of 0.5 to 10 Mrad. 0.5 Mr
If it is less than ad, the curing is insufficient, and if it exceeds 10 Mrad, there is a risk that the thermosensitive recording material will develop color or the electron beam curable resin will be discolored. The irradiation acceleration voltage is preferably about 100 to 300 kV. As an electron beam irradiation method, a curtain beam method, a scanning method, a broad beam method, or the like can be used. The pigment to be blended in the gloss layer of the present invention can be appropriately selected and used from the pigments used in the thermosensitive coloring layer. For coating the ionizing radiation curable glossy layer of the present invention, a coating method such as a Mayer bar method, a blade method, a reverse roll method, a slit die method, a gravure method, etc., which has been conventionally used by those skilled in the art, is used. be able to.

[0032]

The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to these examples. In each example, “part” means “part by weight”. Example 1 A commercially available synthetic paper (Yupo FPG-80, manufactured by Oji Oka Kasei Synthetic Paper Co., Ltd.) was coated on one side with the thermosensitive coloring layer coating composition shown below to give a coating amount of 6.5 g / m ^2. Thus, the intermediate layer coating material was applied thereon so that the coating amount after drying was 2.0 g / m ² . Further, the back layer coating material was applied onto the opposite surface of the synthetic paper so that the coating amount after drying was 1.0 g / m ² . After coating the back layer, super calender treatment was performed to adjust the smoothness of the intermediate layer to 3,000 seconds. Then, 1.5g / m ^{2 of} electron beam curable gloss layer paint was applied and 5Mr
A thermosensitive recording medium was obtained by irradiating an electron beam of ad.

Preparation of paint for thermosensitive coloring layer Liquid A (thermosensitive coloring dye dispersion) 3- (N-ethyl-N-isopentyl) amino-6-methyl-7-anilinofluorane 20 parts 10% polyvinyl alcohol Aqueous solution 20 parts Water 10 parts Liquid B (developing agent dispersion) 4,4'-isopropylidenediphenol 50 parts 10% polyvinyl alcohol aqueous solution 50 parts Water 25 parts Liquids A and B are separately dispersed in Ultraviscomill. The particles were pulverized and adjusted so that the average particle diameter was 1.3 ± 0.3 μm.

Liquid A 30 parts, liquid B 75 parts, 60% calcium carbonate dispersion (Brilliant-15, average particle size 0.15)
μm, Shiraishi Industry Co., Ltd. 55 parts, 10% polyvinyl alcohol aqueous solution 60 parts, SBR latex (L-153)
7, solid content 50%, Asahi Kasei product 28 parts, stearic acid amide dispersion liquid (High Micron G-270, melting point 1
A thermosensitive coloring layer coating material was prepared by mixing 24 parts of 00 ° C., solid content 21%, Chukyo Yushi Co., Ltd. product, and 61 parts of water.・ Intermediate layer paint Kaolinite clay 60% dispersion (UW-90, average particle size 0.5 μm, manufactured by EMC) 108 parts Acrylic modified polyvinyl alcohol 10% aqueous solution (Ricabond SA-70, manufactured by Chuo Rika Kogyo Co., Ltd.) 250 parts Glyoxal (solid content 40%, product of Nippon Synthetic Chemical Industry Co., Ltd.) 25 parts Water 217 parts were mixed to form an intermediate layer paint.

Back layer paint Sodium polystyrene sulfonate 30 parts (Chemistat SA-9, Sanyo Kasei Co., Ltd. solid content 33%) SBR latex 70 parts (0528, Nippon Synthetic Rubber Co., Ltd. solid content 50%) 10% aqueous solution of oxidized starch 150 parts (Ace A manufactured by Oji Corn Starch Co., Ltd.) 60% kaolinite clay slurry (UW-90, 67 parts average particle size 0.5 μm, solid content 60%, manufactured by EMC) 350 parts water The mixture was mixed to obtain a back layer paint. After coating the back layer, super calendar treatment was performed to obtain an intermediate layer having an Oken type smoothness (J.TAPPI No. 5) of 2,000 seconds on the intermediate layer surface. Furthermore, after coating the electron beam curable gloss layer shown below so that the coating amount after curing is 1.5 g / m ² , 5 Mr
An electron beam of ad was irradiated to obtain a gloss layer.

Gloss layer coating pentaerythritol tetraacrylate (trade name: Aronix M-450, Tg ≧ 250 ° C., Toagosei Kagaku Co., Ltd.) 90 parts Calcium carbonate 10 parts (Ryton A, average particle size 1.9 μm, Bihoku Powder Co., Ltd. product was mixed with a three-roll mill to obtain a gloss layer paint.

Example 2 A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the following coating material was used instead of the intermediate layer coating material of Example 1. -Intermediate layer coating calcium carbonate dispersion 100 parts (NS-1000, average particle size 1.17 [mu] m, solid content 70%, Nitto Koka Kogyo Co., Ltd. product) acrylic modified polyvinyl alcohol 10% aqueous solution 250 parts (Ricabond SA-70) , Chuo Rika Kogyo Co., Ltd. Acrylic emulsion 22 parts (SA-2291, solid content 23%, Nippon Shokubai Co., Ltd.) Water 228 parts were mixed to form an intermediate layer paint.

Comparative Example 1 A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the following paint was used instead of the intermediate layer paint.・ Intermediate layer coating calcium carbonate dispersion 100 parts (NS-1000, average particle size 1.17 μm, solid content 70%, Nitto Koka Kogyo Co., Ltd. product) completely saponified polyvinyl alcohol 10% aqueous solution 250 parts (PVA-110, Saponification degree 98.5%, degree of polymerization 1,100, Kuraray Co., Ltd.) Acrylic emulsion (SA-2291, solid content 23%, Nippon Shokubai Co., Ltd.) 22 parts Water 228 parts are mixed to form an intermediate layer paint. And

Comparative Example 2 A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the following coating material was used instead of the intermediate layer coating material. -Intermediate layer coating calcium carbonate dispersion 100 parts (NS-1000, average particle size 1.17 [mu] m, solid content 70%, Nitto Koka Kogyo Co., Ltd. product) Carboxy modified polyvinyl alcohol 10% aqueous solution (Gothenal T-330, Japan Synthetic Chemical Industry Co., Ltd. product 250 parts Acrylic emulsion (SA-2291, solid content 23%, Nippon Shokubai Co., Ltd. product) 22 parts Water 228 parts were mixed to form an intermediate layer paint.

Comparative Example 3 A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the following paint was used instead of the intermediate layer paint. -Intermediate layer paint: Carboxy modified polyvinyl alcohol 10% aqueous solution 500 parts (Gosenal T-330, Nippon Synthetic Chemical Industry Co., Ltd. product) Acrylic emulsion (SA-2291, solid content 23%, Nippon Shokubai Co., Ltd. product) 217 parts The mixture was mixed to obtain an intermediate layer paint.

The thermal recording materials obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were conditioned for 2 hours under the conditions of 20 ° C. and 65% RH, and then commercially available thermal printers (UP-86).
0, made by Sony) was used for gradation recording. The results are as shown in Table 1, and the glossiness is high in Examples 1 and 2,
The image uniformity was good, and the recording unevenness and sticking noise of the stick were small, whereas the image uniformity was poor in Comparative Examples 1 and 2, and the sticking noise was large in Comparative Example 3 and recording unevenness also occurred. did.

[0042]

[Table 1]

Light intensity: Measured according to JIS P 8142. Image uniformity: After adjusting the humidity of the recording paper for 2 hours under the environmental condition of 20 ° C. and 65% RH, UP-860 (product of Sony Corporation)
The printer performs 17-step halftone recording and evaluates the uniformity of the recorded image. ◯: Good. X: Small white spots are visible and the color is not uniformly developed. Adhesive strength: A commercially available cellophane tape is attached to the surface of the glossy layer, and then peeled off in the direction of 180 ° C. ◯: Does not peel off. Δ: Slightly peeled off. X: It peels off considerably. Recording Muller: Evaluates horizontal stripe-like density unevenness during 17-step recording. ◯: Almost no unevenness. X: The unevenness is clearly seen. Stick sound: When recording 17 steps, the loudness of recording sound is evaluated. ○: There is almost no sound. X: A loud noise is generated and horizontal stripe-shaped recording unevenness occurs.

[0044]

According to the present invention, it is possible to obtain a heat-sensitive recording material having good gloss and uniformity of image, high adhesive strength of glossy layer and good stickiness.

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[Procedure amendment]

[Submission date] March 25, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

However, it is necessary that the mixed liquid does not develop color, aggregate, or have a high viscosity when mixed with the respective dispersion liquids of the color forming dye and the color developer, and the formed heat-sensitive The recording layer film is tough,
It is necessary to have no desensitizing effect. The content of the adhesive in the thermosensitive coloring layer is preferably 8 to 30% by weight, and 8% by weight
If it is less than 30% by weight, the coating strength is low, and if it exceeds 30% by weight, the sensitivity is lowered.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

Further, in order to improve the water resistance of the thermosensitive coloring layer, a crosslinking agent for curing the resin can be used if necessary. For example, glyoxal, dialdecht compound such as dialdehyde starch, polyamine compound such as polyethyleneimine, epoxy compound, polyamide resin, melamine resin, diglycidyl compound such as glycerin diglycidyl ether, dimethylol urea compound, aziridine compound, block 1 to 10% by weight of an isocyanate compound and an inorganic compound such as ammonium persulfate, ferric chloride, and magnesium chloride
It can be used in the range of.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

If desired, a crosslinking agent and a lubricant may be added to the intermediate layer of the present invention. The cross-linking agent can be appropriately selected and used from those used for the thermosensitive color developing layer. The compounding amount of the crosslinking agent is 30 with respect to the solid content of the intermediate layer.
It is preferably less than or equal to wt%. Lubricants used in the intermediate layer of the present invention include, for example, waxes such as zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax and ester wax, lauryl phosphate ester, oleyl phosphate ester, stearyl phosphate ester and the like. Alkyl phosphates and their alkali metal salts, lauryl sulfonates, oleyl sulfonates, stearyl sulfonates and other alkyl sulfonates and their alkali metal salts, glyceryl monomyristate, glyceryl monostearate, monooleic acid Glyceryl fatty acid esters such as glyceryl, glyceryl distearate and glyceryl dioleate, diglyceryl monolaurate, diglyceryl dilaurate, teremonolaurate Raguriseriru, monolauryl hexaglyceryl, there are polyglycerol fatty acid esters such as monolaurate decaglyceryl, desensitizing effect from them decoloring action, it is necessary to select a without background color effects. It is desirable to add the lubricant in an amount of 10% by weight or less based on the solid content of the intermediate layer.

Claims (1)

[Claims] 1. A thermosensitive coloring layer containing a colorless or light-colored electron-donating leuco dye, an organic acidic substance that develops the color of the leuco dye by heating, and an adhesive as main components on at least one surface of a support, and the thermosensitive coloring. A heat-sensitive recording material in which an intermediate layer made of a water-based paint is further provided on the layer, and a gloss layer containing an ionizing radiation curable resin is further provided on the intermediate layer in order to contain an acrylic modified polyvinyl alcohol as a resin forming the intermediate layer. And a recording material containing an acrylic resin as the ionizing radiation curable resin for the glossy layer.