JP2001199163A - Heat sensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sensitive recording material excellent in the light fastness of a color image and a ground texture (or a white ground) under the condition that the lustrous properties of the material is kept as they are. SOLUTION: In the heat sensitive recording material having a heat sensitive recording layer and a protective layer on a support, the protective layer includes a silicon-modified polymer and either one of the layers of the heat sensitive recording material includes a swelling inorganic lamellar compound. Preferably, the protective layer includes gelatin together with the silicon-modified polymer. As either one layer of the heat sensitive recording material, a second protective layer or a light transmittance adjusting layer provided between the heat sensitive recording layer and the protective layer, an intermediate layer provided between the heat sensitive recording layer and the protective layer or the like are exampled.

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 excellent in light fastness of a color image and a background (white background) while maintaining glossiness.

[0002]

2. Description of the Related Art Thermosensitive recording has recently been developed because its recording device is simple, reliable and requires no maintenance. As its thermosensitive recording material, an electron-donating colorless dye and an electron-accepting compound have conventionally been used. And those utilizing the reaction between a diazonium salt compound and a coupler are widely known. Thermal recording materials, especially
In a multicolor heat-sensitive recording material, an intermediate layer is provided between the heat-sensitive recording layers in order to prevent color mixing between the heat-sensitive recording layers. This intermediate layer not only suppresses the transmission of the color-forming substance to prevent color mixing, but also suppresses the transmission of oxygen to prevent coloring of the background portion by light and oxygen, and discoloration and fading of the image portion. It also has functions.

[0003]

SUMMARY OF THE INVENTION On the other hand, the present inventors have
By using an aqueous silicone-modified polymer and an aqueous binder for a protective layer provided on the heat-sensitive recording layer, a heat-sensitive recording material excellent in glossiness is proposed (Japanese Patent Application No. 10-35).
3471). In this thermosensitive recording material, when gelatin is used as the aqueous binder, particularly good gloss can be obtained. However, since this protective layer has a high oxygen transmittance, it has been found that the light fastness of the color image and the background (white background) is deteriorated.

It is an object of the present invention to maintain gloss while
An object of the present invention is to provide a heat-sensitive recording material having excellent light fastness of a color image and a background (white background).

[0005]

An object of the present invention is to provide a heat-sensitive recording material having a heat-sensitive recording layer and a protective layer on a support, wherein the protective layer contains a silicone-modified polymer, and at least one of the heat-sensitive recording materials is provided. This is achieved by a heat-sensitive recording material characterized in that the layer contains a swellable inorganic layered compound. The protective layer preferably contains a silicone-modified polymer and gelatin, and the support preferably has oxygen barrier properties. Further, a second protective layer or a light transmittance adjusting layer is provided between the heat-sensitive recording layer and the protective layer, and the second protective layer or the light transmittance adjusting layer contains a swellable inorganic layered compound. Is preferred. Further, the heat-sensitive recording layer has two or more heat-sensitive recording layers and an intermediate layer between these heat-sensitive recording layers, and among these heat-sensitive recording layers, swells in the intermediate layer on the layer having the lowest light fastness. It is preferable to contain an inorganic layered compound. The silicone-modified polymer preferably has a glass transition temperature (Tg) of 60 ° C. or higher.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. In the heat-sensitive recording material of the present invention,
A heat-sensitive recording layer and a protective layer are provided on a support. The protective layer contains a silicone-modified polymer, and any layer of the heat-sensitive recording material contains a swellable inorganic layered compound. The silicone-modified polymer contained in the protective layer on the heat-sensitive recording layer is a silicone graft polymer, a silicone block polymer,
Preferred are silicone-modified acrylic polymers and silicone-modified polyvinyl alcohol. Further, as the silicone graft polymer, a silicone graft acrylic polymer and a silicone graft modified polyvinyl alcohol are preferable, and as the silicone block polymer, a silicone block acrylic polymer and a silicone block modified polyvinyl alcohol are preferable.

[0007] The trunk polymer of the silicone-modified polymer is
Any resin may be used as long as it has characteristics such as high Tg (glass transition point), which is excellent in film forming property, heat resistance, light resistance, and film strength, and acrylic resin and polyvinyl alcohol resin are particularly preferable. It is preferably used.

The monomers constituting such an acrylic resin include acrylic resins such as methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and glycidyl (meth) acrylate. Monomers. Further, non-acrylic copolymerizable monomers such as styrene, acrylonitrile, vinyl acetate, N-vinylpyrrolidone, and Nt-butylacrylamide may be copolymerized. In the case of a water-soluble type, as a water-solubility imparting unit, and in the case of an emulsion type or latex type, as a dispersion stability imparting unit, (meth) acrylic acid (or a salt thereof), maleic acid (or a salt thereof), Itaconic acid (or its salt), styrenesulfonic acid (or its salt), 2-acrylamide-2
-Methylpropanesulfonic acid (or a salt thereof), 2-hydroxyethyl (meth) acrylate, acrylamide,
It is preferable to include a monomer such as dimethylacrylamide, dimethylaminoethyl (meth) acrylate (or a salt thereof), or polyethylene glycol monomethyl ether mono (meth) acrylate.

As the branch polymer of the silicone-modified polymer, any silicone may be used, but polydimethylsiloxane is preferably used. Polydimethylsiloxane has excellent properties in terms of water repellency and lubricity.

Therefore, a copolymer having a unit derived from the acrylic monomer and a polydimethylsiloxane unit is excellent in film forming property, heat resistance, light resistance, film strength, water repellency and lubricity. Are better.

As the silicone-modified polymer in the present invention, a silicone graft polymer is preferable. Among the silicone graft polymers, a copolymer of a silicone macromonomer represented by the general formula (1) and a monomer copolymerizable therewith is preferred. Among them, those represented by the general formula (2) are particularly preferred.

[0012]

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In the general formula (2), R ¹ is an alkyl group having 1 to 6 carbon atoms, R ² is —COOR ⁷ , an aryl group, a cyano group, an imidazole group, a triazole group, a pyrrolidone group,
—OCOR ⁷ (R ⁷ represents an alkyl group, an aryl group, or an aralkyl group), R ³ , R ⁴ , R ⁵ , and R ⁶ each represent hydrogen or a methyl group, X represents a hydrophilic group, and Y represents a reactive group. ,
n is a positive integer, m is 2 to 6, a, b, c, d (however,
c may be 0. ) Represents the degree of polymerization.

In the general formula (2), examples of the hydrophilic group (X) include a polyethylene oxide group, a polypropylene oxide group, a carboxy (or salt thereof) group, a hydroxy group, a sulfonic acid (or salt thereof) group and an amino group. Group,
Amide group, substituted amide group, an ammonium base and groups having these functional groups (e.g., -COOCH ₂ CH ₂ O
_{H, -COO (CH 2 CH 2} O) n H), and the like. Further, as the reactive group (Y), a group capable of reacting with a crosslinking agent and / or a binder, for example, an amino group, a carboxy (or a salt thereof) group, a hydroxy group, a sulfinic acid (or a salt thereof) group, a glycidyl group And groups having these functional groups.

Depending on the composition of the monomers, these silicone-grafted acrylic polymers may be solution-polymerized with an azobis compound or an organic peroxide in an organic solvent such as isopropyl alcohol, toluene, or xylene, or may be a nonionic polymer. It is manufactured by emulsion polymerization using potassium persulfate or the like in the presence of anionic and cationic surfactants.

The silicone-modified polyvinyl alcohol derivative is a polymer having a repeating unit (polysiloxane chain) of the general formulas (3) and (4).

[0017]

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In the general formula (4), R ¹ and R ² are each an alkyl group having 6 or less carbon atoms or an aryl group. Examples of the substituent on the polysiloxane chain include a methyl group, an ethyl group, and a phenyl group. Of these, polymethylsiloxane is particularly preferable from the viewpoint of availability of raw materials.

The silicone-modified polymer in the present invention is prepared from a water-soluble type, an emulsion type, a latex type, a solvent miscible with water such as alcohol, or a type dissolved in a mixed solvent of these solvents and water. At this time, any of the types excluding the solvent before the preparation may be used, but the water-soluble type, or a solvent miscible with water such as alcohol, or a type dissolved in a mixed solvent of these solvents and water may be used as a coating liquid. At the time of production, a type in which the solvent is removed before production is preferable.

The Tg of these silicone-modified polymers
(Glass transition point) is 60 ° C. or more, preferably 8
The temperature is 0 ° C or higher, particularly preferably 100 ° C or higher. When the Tg (glass transition point) of the silicone-modified polymer is lower than 60 ° C., the slipperiness with the head during printing decreases, which is not preferable.

In the binder of the protective layer in the heat-sensitive recording material of the present invention, 5 to 100 silicone-modified polymers are contained.
% By weight, more preferably 50 to 90% by weight. When the content of the silicone-modified polymer is less than 5% by weight, the above-mentioned properties of the silicone-modified polymer are not sufficiently exhibited.

In the protective layer, other aqueous binder components may be used in addition to the silicone-modified polymer, if necessary. Other aqueous binders include methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, starches, agar, κ -Carrageenan, gelatin, gum arabic, casein, styrene-maleic anhydride copolymer hydrolyzate, ethylene-maleic anhydride copolymer hydrolyzate, isobutylene-maleic anhydride copolymer hydrolyzate, polyvinyl alcohol, modified Examples include polyvinyl alcohol and polyacrylamide.

Among these polymers, a water-soluble polymer that can be set and dried is preferable in that it has high surface smoothness in the background portion and the printing surface and is excellent in glossiness. The water-soluble polymer that can be set and dried is used when heated (for example, at 40 ° C.).
(Before and after), a water-soluble polymer that exhibits a predetermined viscosity and can be applied, and then, when cooled (for example, 5 ° C. to 15 ° C.), increases in viscosity, stops flowing, and gels.

In the present invention, suitable aqueous binders in terms of being set-dryable include proteins such as gelatin, polysaccharides such as carrageenan and agar, and polyvinyl alcohol compounds, and the like. Gelatin is particularly preferred for its superiority. When gelatin and silicone-modified polymer are used, the ratio (silicone-modified polymer / gelatin) is 50/50 by weight.
~ 90/10 is preferred. The polyvinyl alcohol compound can be gelled by boric acid or a salt thereof.

Further, in the case of a polyvinyl alcohol-based compound, silanol-modified polyvinyl alcohol is preferable as the aqueous binder because of good compatibility with the silicone-modified polymer, and silanol-modified polyvinyl alcohol is preferably used as boric acid or gelling agent. When used in combination with a salt thereof, it can be used as a set-dryable water-soluble polymer. When a silanol-modified polyvinyl alcohol and a silicone-modified polymer are used, the ratio (silicone-modified polymer / silanol-modified polyvinyl alcohol) is preferably 5/95 to 95/5, more preferably 50/50 to 90/10, by weight. .

In the present invention, the silicone-modified polymer alone is difficult to set and dry, and when used in combination with the above-described set-dryable water-soluble polymer, formation of the protective layer is facilitated. In the case of a protective layer formed by such a method, the silicone-modified polymer tends to be oriented near the surface of the protective layer. Therefore, on the surface side of the protective layer, it is possible to prevent adhesion of the thermal recording head and the like due to the lubricating property of the silicone, adhesion of scum, and the like, and to impart a smoothing effect of the protective layer surface by the thermal recording head and the like,
The follow-up property of the heat-sensitive recording head and the like is good, and the color density can be increased without any printing failure.

As the aqueous binder, a synthetic rubber latex or a synthetic resin emulsion may be used. Examples of monomers constituting latex and emulsion of these polymers include acrylates, methacrylates, crotonic esters, vinyl esters, maleic diesters, fumaric diesters, itaconic diesters, acrylamides, and methacrylic acid. Examples include amides, vinyl ethers, styrenes, and acrylonitrile.

It is desirable to use a crosslinking agent which undergoes a crosslinking reaction with the silicone-modified polymer and / or the aqueous binder.
Or the aqueous binder is a carboxy group as a functional group,
Amino group, ammonium base, hydroxy group, sulfinic acid (or salt thereof) group, sulfonic acid (or salt thereof) group,
Alternatively, it is desirable to have at least one functional group selected from glycidyl groups.

Examples of the above crosslinking agent include vinyl sulfone compounds, aldehyde compounds (formaldehyde, glutaraldehyde, dialdehyde starch, etc.), epoxy compounds, oxazine compounds, triazine compounds, Polymer hardeners described in JP-A-234157, methylated melamine, blocked isocyanates, methylol compounds, carbodiimide resins and the like can be used.

Among these crosslinking agents, vinyl sulfone compounds, aldehyde compounds, epoxy compounds, oxazine compounds, triazine compounds,
The polymer hardener described in JP-A-234157 is preferred.

The amount of the crosslinking agent used for the water-soluble polymer, polymer latex or polymer emulsion is 1 to 50 parts by weight based on 100 parts by weight of the water-soluble polymer, polymer latex or polymer emulsion. It is desirable to mix. When the compounding amount of the crosslinking agent is less than 1 part by weight, the degree of crosslinking modification is low, and the water resistance and chemical resistance become insufficient. On the other hand, when it exceeds 50 parts by weight, the liquid stability decreases, and Absent.

The protective layer may contain ultrafine inorganic particles having an average primary particle size of 0.1 μm or less. Here, the inorganic ultrafine particles refer to inorganic fine particles having an average primary particle size of 0.1 μm or less, and are not particularly limited as long as the average primary particle size is 0.1 μm. The threshold value at the larger particle size distribution in the liquid is preferably 0.5 μm or less, more preferably 0.4 μm or less, and particularly preferably 0.35 μm or less. The particle diameter of the dispersion is 0.35 μm.
m (aggregated) particles have a frequency of 5% or less, preferably 1% or less.
% Or less, and the frequency of (agglomerated) particles of 0.25 μm or more is particularly preferably 5% or less. The particle size can be measured by a known method, for example, a COULTER N4 type submicron particle size analyzer (Nikkaki).

As the inorganic ultrafine particles, barium sulfate, zinc oxide, magnesium oxide, lead oxide, zirconium oxide, colloidal silica or alumina inorganic ultrafine particles are preferable, and among these, barium sulfate, colloidal silica and alumina are particularly preferable. .

The inorganic ultrafine particles may be used alone or in combination of two or more. In particular, colloidal silica has a high activity, and when performing simultaneous multi-layer coating, depending on the combination, the coating may be uneven due to the interaction with the compound of another layer, and the surface smoothness of the resulting heat-sensitive recording material may be impaired. Therefore, when colloidal silica is used, it is preferable to use colloidal silica and other inorganic ultrafine particles in combination, and the mixing ratio (colloidal silica / other inorganic ultrafine particles) is 1/9 to 6/4 by weight. Is preferred, and a blend ratio of 2/8 to 5/5 is more preferred. As the combination of the inorganic ultrafine particles to be used together, a combination of colloidal silica and barium sulfate is preferable, and it is more preferable to use colloidal silica and barium sulfate in a mixing ratio of 2/8 to 5/5.

In the present invention, the amount of the inorganic ultrafine particles to be added to the protective layer is 0.01 to 1 g / m ² ,
% By weight, preferably 5 to 50% by weight. 0.01g
/ M less than ² and the effect of adding the inorganic ultrafine particles is insufficient, there is a case where glossiness exceeds 1 g / m ² is reduced.

The coating liquid for the protective layer of the present invention contains silicone-modified
In addition to the polymer and inorganic ultrafine particles, if necessary,
Other aqueous binders, crosslinking agents, catalysts, release agents, surfactants
Agent, wax, water repellent, etc. can be added and obtained
Apply the protective layer coating solution on the heat-sensitive recording layer with a bar coater or air coater.
F coater, blade coater, curtain coater, etc.
The protective layer of the present invention is obtained by coating and drying using an apparatus.
However, the protective layer may be applied simultaneously with the recording layer,
After applying the heat-sensitive recording layer, the heat-sensitive recording layer is once dried, and
It may be applied on top. The dry coating amount of the protective layer is
0.1-3g / m ^TwoIs more preferable, and more preferably 0.1.
3 to 2.0 g / m^TwoIt is. If the amount of coating is large, it will be extremely hot
Decreases sensitivity and protects at too low coating levels
Demonstrates layer function (friction resistance, lubricity, scratch resistance, etc.)
Can not. After applying the protective layer,
May be applied.

Next, in the present invention, at least one of the layers of the heat-sensitive recording material contains a swellable inorganic layered compound. As the layer containing the swellable inorganic layered compound, for example, a layer that can effectively impart oxygen barrier properties to the heat-sensitive recording layer by containing the swellable inorganic layered compound is preferable. As such a layer, for example, (1) When a second protective layer or a light transmittance adjusting layer is provided between the heat-sensitive recording layer and the protective layer, the second protective layer or the light transmittance adjusting layer swells. A layered inorganic compound. (2) When the heat-sensitive recording layer has two or more heat-sensitive recording layers and an intermediate layer between these heat-sensitive recording layers, at least one of these intermediate layers contains a swellable inorganic layered compound. In particular, among these heat-sensitive recording layers, the intermediate layer on the layer having the lowest light fastness contains a swellable inorganic layered compound. (3) The protective layer contains a swellable inorganic layered compound. And so on.

In the present invention, the water-swellable synthetic mica is particularly preferred as the swellable inorganic layered compound. The water-swellable synthetic mica used in the present invention has a general formula A (B,
C) _2-3 D ₄ O ₁₀ (OH, F, O) ₂ [where A is K,
Na or Ca, B and C are FeII, FeIII,
Mn, Al, Mg, or V, and D is Si or A
1).

In the above mica group, Na tetrasilyl
Kumaika NaMg_Two._Five(Si_FourO_Ten) F_Two, Na or L
i Teniolite (Na, Li) Mg_TwoLi (Si
_FourO_Ten) F _Two, Montmorillonite Na or Li hex
Tolite (Na, Li)_1/8Mg_{2 / Five}Li_1/8(Si_Four
O_Ten) F_TwoAnd water-swellable mica. The present invention
In other words, fluorine-based swellable mica, which is a synthetic layered compound,
Particularly useful.

The water-swellable synthetic mica used in the present invention has an aspect ratio of 50 or more, preferably 100 or more.
Particularly preferably, it is 200 or more. The aspect ratio is the ratio of the thickness to the major axis of the particle. The greater the aspect ratio, the greater the effect of oxygen barrier properties. The particle diameter of the water-swellable synthetic mica used in the present invention has an average major axis of 0.3.
It is 20 to 20 m, preferably 0.5 to 10 m, particularly preferably 1 to 5 m. The average thickness of the particles is 0.1.
It is 1 μm or less, preferably 0.05 μm or less.

When the water-swellable synthetic mica particles having a large aspect ratio are contained in any layer of the heat-sensitive recording material, the oxygen-blocking property to the heat-sensitive recording layer is improved, and the swellable inorganic material is used. Not only is the elastic modulus and strength of the layer containing the layered compound particles increased, but also the thermal expansion coefficient and the molding shrinkage become uniform in the two-dimensional direction and become smaller, so that curling of the recording material is prevented. It is estimated that

First, (1) when a second protective layer or a light transmittance adjusting layer is provided between the heat-sensitive recording layer and the protective layer, the swellable inorganic layered compound is added to the second protective layer or the light transmittance adjusting layer. Can be contained. Here, the second protective layer is a protective layer formed on the lower surface of a protective layer (hereinafter, also referred to as a surface protective layer) constituting the outermost surface of the heat-sensitive recording material. The binder is not particularly limited, but a modified or unmodified polyvinyl alcohol or the like can be preferably used, and the swellable inorganic layered compound is used in an amount of 0.01 to 0.3 g / m ² , preferably 0.02 to 0.3 g / m ² .
0.2 g / m ² is preferably contained.
If it is less than 1 g / m ² , the oxygen barrier property is not sufficient, and
If it exceeds / m ² , failures such as a decrease in glossiness and clouding of air bubbles occur.

In the case of a full-color heat-sensitive recording layer, a light-fixing type heat-sensitive recording layer is provided on a support with a light transmittance adjusting layer whose light transmittance in a wavelength region where light is fixed is reduced after fixing. Is preferable, and the light transmittance adjusting layer can contain a swellable inorganic layered compound.

In the present invention, the light transmittance adjusting layer containing the swellable inorganic layered compound has a component which has an oxygen barrier property and functions as a precursor of an ultraviolet absorber, and has a region necessary for fixing. Since it does not function as an ultraviolet absorber before irradiation with light of a wavelength, it has a high light transmittance, and when fixing a light-fixing type thermosensitive recording layer, sufficiently transmits wavelengths in a region necessary for fixing, and transmits visible light. The rate is high, and there is no problem in fixing the heat-sensitive recording layer.

The precursor of the ultraviolet absorbent is converted into an ultraviolet absorbent by reacting with light or heat after the light irradiation of the wavelength necessary for fixing the light fixing type thermosensitive recording layer by light irradiation is completed. As a result, most of the light in the wavelength range necessary for fixing in the ultraviolet region is absorbed by the ultraviolet absorber, the transmittance is reduced, and the light resistance of the heat-sensitive recording material is improved. Because there is no absorption effect,
The visible light transmittance is not substantially changed.

At least one light transmittance adjusting layer can be provided in the light fixing type thermosensitive recording material, and most preferably, it is formed between the light fixing type thermosensitive recording layer and the surface protective layer. The transmittance adjusting layer may be used also as the protective layer. The characteristics of the light transmittance adjusting layer can be arbitrarily selected according to the characteristics of the light fixing type thermosensitive recording layer.

(2) When the heat-sensitive recording layer has two or more heat-sensitive recording layers and an intermediate layer between these heat-sensitive recording layers, at least one of these intermediate layers contains a swellable inorganic layered compound. In particular, among these heat-sensitive recording layers, it is preferable to include a swellable inorganic layered compound in the intermediate layer on the layer having the lowest light fastness. In general, in a full-color thermosensitive recording material in which the thermosensitive recording layer has cyan, yellow, and magenta thermosensitive recording layers, the light fastness of the magenta thermosensitive recording layer is low. It is preferable to include a layered compound.

The binder used in the intermediate layer of the present invention is not particularly limited as long as it exhibits the above physical properties, and aqueous polymers such as polyvinyl alcohol-based, polyamide-based, and polymers having an amide group and a carboxyl group can be used. Can be. Among them, a polyvinyl alcohol-based aqueous polymer is preferable in terms of low oxygen permeability at room temperature and set drying by adding boric acid or a salt thereof, and contains at least 70% or more of vinyl alcohol as a monomer unit. Modified polyvinyl alcohol is more preferred. Further, among the modified polyvinyl alcohols, carboxy-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, and epoxy-modified polyvinyl alcohol are preferable from the viewpoint of adhesion to an adjacent layer.

The amount of the swellable inorganic layered compound, particularly the water-swellable synthetic mica used in the intermediate layer is 0.01 to 0.3 g.
/ M ² , more preferably 0.02 to 0.2 g
/ M ² . The amount of the swellable inorganic layered compound used is 0.0
When it is less than 1 g / m ² , the oxygen barrier property becomes insufficient,
If it exceeds 0.3 g / m ² , the gas permeability at the time of printing becomes insufficient, and the gloss is deteriorated.

The intermediate layer containing a swellable inorganic layered compound, particularly a synthetic mica having water swellability, does not degrade the transparency of the layer and has a good barrier performance against a coloring substance. 5 to 45% of the thickness of the intermediate layer made of only a binder such as a conductive polymer has the same barrier performance. That is, by increasing the barrier performance, the thickness of the intermediate layer can be reduced, and the sharpness, sensitivity (printing speed), and curling resistance of the recording material can also be improved.

Next, in the heat-sensitive recording material of the present invention, various known supports can be used as the support, and plastic films, papers, plastic resin laminated papers, synthetic papers and the like can be used. However, it is particularly preferable to use a support having oxygen barrier properties. Here, the support having oxygen barrier properties means a support having an oxygen permeability of 10 ml / m ² · hr · atm at 25 ° C. and 40% RH.

As such a support, 1) a laminated film obtained by laminating a polyester resin such as polyethylene terephthalate, 2) a laminated paper such as a polyethylene resin layer / polyvinyl alcohol layer / paper / polyethylene resin layer, and 3) an evar laminated paper And 4) an oxygen permeation rate of 10 at 25 ° C. and 40% RH from laminated paper or the like coated with a layer containing the swellable inorganic layered compound.
It is preferable to select one having a value of not more than ml / m ² · hr · atm. Oxygen permeability is measured according to JIS K7126 (198
7) -B method (value obtained by the equal pressure method). By using these supports, entry of oxygen from the support side can be prevented, and the light fastness of the color image and the background (white background) can be improved.

In the present invention, when a support having a relatively high oxygen permeability is used as the support, an undercoat layer is provided, and a water-soluble polymer compound is used as the binder having excellent oxygen barrier properties in the undercoat layer. it can. Examples of such a water-soluble polymer compound include, for example, polyvinyl alcohol, modified polyvinyl alcohol, methyl cellulose, sodium polystyrene sulfonate, styrene-maleic acid copolymer, gelatin, and the like. A polymer compound layer is preferably used.

The heat-sensitive recording layer of the present invention may be a full-color heat-sensitive recording layer or a mono-color heat-sensitive recording layer, but may be a diazonium salt compound or a coupler which reacts with the diazonium salt compound on a support. It is desirable to have at least one heat-sensitive recording layer containing a binder as a main component. In particular, it is desirable that the heat-sensitive recording layer has a heat-sensitive recording layer formed of a diazo system for each of cyan, yellow, and magenta.

In the heat-sensitive recording layer of the present invention, a multicolor heat-sensitive recording material can be obtained by changing the hue of each heat-sensitive recording layer. That is, a full-color image can be recorded by selecting the coloring hues of the respective heat-sensitive recording layers so as to be three primary colors, yellow, magenta, and cyan in the subtractive color mixing.
In this case, the color-forming mechanism of the heat-sensitive recording layer directly laminated on the support surface (the lowermost layer of the heat-sensitive recording layer) is a color-forming system composed of an electron-donating dye and an electron-accepting dye, for example, a diazonium salt and a diazonium salt. Any of a diazo coloring system, a base coloring system that forms a color by contacting with a basic compound, a chelate coloring system, a coloring system that reacts with a nucleophile to cause a elimination reaction to form a color may be used. Preferably, a diazo coloring system is provided, and two layers of light-fixing type thermosensitive recording layers each containing a diazonium salt compound having a different maximum absorption wavelength and a coupler reacting with the diazonium salt compound to form a color are provided on the thermosensitive recording layer. It is desirable to provide a light transmittance adjusting layer containing a swellable inorganic layered compound and an outermost protective layer on the layer.

In the present invention, as the color-forming component used in the heat-sensitive recording layer, conventionally known color-forming components can be used. In particular, those utilizing a reaction between a diazonium salt compound and a coupler, or an electron-donating colorless dye and an electron-accepting dye are used. Compounds utilizing a reaction with a hydrophilic compound are preferable. Examples of the compound used in the heat-sensitive recording layer containing a diazonium salt compound and a coupler that reacts with the diazonium salt compound when heated to form a color include a diazonium salt compound and the diazonium salt. In addition to a coupler capable of forming a dye by reacting with a compound, a basic substance which promotes a reaction between the diazonium salt compound and the coupler and the like can be mentioned. The diazonium salt compounds are compounds shown below, and can control the maximum absorption wavelength depending on the position and type of the substituent in the Ar portion.

[0057]

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Ar represents an aryl group, and X ⁻ represents an acid anion.

Specific examples of the diazonium salt compound in the present invention include 4- (N- (2- (2,4-di-
tert-amylphenoxy) butyryl) piperazino)
Benzenediazonium, 4-dioctylaminobenzenediazonium, 4- (N- (2-ethylhexanoyl)
Piperazino) benzenediazonium, 4-dihexylamino-2-hexyloxybenzenediazonium, 4-
N-ethyl-N-hexadecylamino-2-ethoxybenzodiazonium, 3-chloro-4-dioctylamino-2-octyloxyobenzenediazonium, 2,5
-Dibutoxy-4-morpholinobenzenediazonium,
2,5-octoxy-4-morpholinobenzenediazonium, 2,5-dibutoxy-4- (N- (2-ethylhexanoyl) piperazino) benzenediazonium, 2,
5-diethoxy-4- (N- (2- (2,4-di-te
acid anion salts such as rt-amylphenoxy) butyryl) piperazino) benzenediazonium, 2,5-dibutoxy-4-tolylthiobenzenediazonium, 3- (2-octyloxyethoxy) -4-morpholinobenzenediazonium and the following diazonium salts Compound D-1
To D-5. The diazonium salt compound is particularly preferably a hexafluorophosphate salt, a tetrafluoroborate salt, or a 1,5-naphthalene sulfonate salt.

[0060]

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Among these diazonium salt compounds, particularly preferred compounds in the present invention are 300 to 40.
4- (N- (2-
(2,4-di-tert-amylphenoxy) butyryl) piperazino) benzenediazonium, 4-dioctylaminobenzenediazonium, 4- (N- (2-ethylhexanoyl) piperazino) benzenediazonium,
4-dihexylamino-2-hexyloxybenzenediazonium, 4-N-ethyl-N-hexadecylamino-2-ethoxybenzodiazonium, 2,5-dibutoxy-4- (N- (2-ethylhexanoyl) piperazino) Benzenediazonium, 2,5-diethoxy-4-
(N- (2- (2,4-di-tert-amylphenoxy) butyryl) piperazino) benzenediazonium and the compounds shown in the specific examples D-3 to D-5. The maximum absorption wavelength of the diazonium salt compound referred to herein is a spectrophotometer (Shimazu MPS-200) obtained by coating each compound with a coating film of 0.1 g / m ² to 1.0 g / m ^2.
0).

Examples of the couplers used in the present invention, which react with the diazonium salt upon heating to give a color, include resorcinol,
Fluluglucin, 2,3-dihydroxynaphthalene-6
Sodium sulfonate, morpholinopropylamide 1-hydroxy-2-naphthoate, 1,5-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,3
-Dihydroxy-6-sulfanylnaphthalene, 2-hydroxy-3-naphthoic acid anilide, 2-hydroxy-
3-naphthoic acid ethanolamide, 2-hydroxy-3
-Naphthoic acid octylamide, 2-hydroxy-3-naphthoic acid-N-dodecyloxypropylamide, 2-hydroxy-3-naphthoic acid tetradecylamide, acetanilide, acetoacetanilide, benzoylacetoanilide, 2-chloro-5-octyl Acetoacetanilide, 1-phenyl-3-methyl-5-pyrazolone, 1-
(2′-octylphenyl) -3-methyl-5-pyrazolone, 1- (2 ′, 4 ′, 6′-trichlorophenyl)
-3-benzamide-5-pyrazolone, 1- (2 ',
4 ', 6'-trichlorophenyl) -3-anilino-5
-Pyrazolone, 1-phenyl-3-phenylacetamido-5-pyrazolone, and the following C-1 to C-6 compounds. By using two or more of these couplers together, a desired color hue can be obtained.

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Examples of the basic substance include an inorganic or organic basic compound, and a compound which decomposes upon heating to release an alkaline substance. Representatives include organic ammonium salts, organic amines, amides, ureas and thioureas and their derivatives, thiazoles, pyrroles, pyrimidines, piperazines, guanidines, indoles, imidazoles, imidazolines,
Nitrogen-containing compounds such as triazoles, morpholines, piperidines, amidines, formazines, pyridines and the like can be mentioned. Specific examples of these include tricyclohexylamine, tribenzylamine, octadecylbenzylamine, stearylamine, allylurea, thiourea,
Methylthiourea, allylthiourea, ethylenethiourea,
2-benzylimidazole, 4-phenylimidazole, 2-phenyl-4-methylimidazole, 2-undecylimidazoline, 2,4,5-trifuryl-2-imidazoline, 1,2-diphenyl-4,4-dimethyl-
2-imidazoline, 2-phenyl-2-imidazoline,
1,2,3-triphenylguanidine, 1,2-dicyclohexylguanidine, 1,2,3-tricyclohexylguanidine, guanidine trichloroacetate, N, N ′
-Dibenzylpiperazine, 4,4'-dithiomorpholine, morpholinium trichloroacetate, 2-aminobenzothiazole, 2-benzoylhydrazinobenzothiazole and the like. These can be used in combination of two or more.

Examples of the electron-donating dye precursor used in the present invention include triarylmethane compounds, diphenylmethane compounds, thiazine compounds, xanthene compounds, spiropyran compounds, and the like. Xanthene compounds are useful because they have a high coloring density. To illustrate some of these,
3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (that is, crystal violet lactone), 3,3-bis (p-dimethylamino) phthalide, 3- (p-dimethylaminophenyl) -3 − (1,
3-dimethylindol-3-yl) phthalide, 3-
(P-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3- (o-methyl-p
-Diethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 4,4'-bis (dimethylamino) benzhydrin benzyl ether, N-halophenylleucouramine, N-2,4,5 -Trichlorophenylleuco auramine, rhodamine-B-anilinolactam, rhodamine (p-nitroanilino) lactam, rhodamine-B- (p-chloroanilino) lactam, 2-benzylamino-6-diethylaminofluoran, 2-anilino-6 -Diethylaminofluoran, 2
-Anilino-3-methyl-6-diethylaminofluoran, 2-anilino-3-methyl-6-cyclohexylmethylaminofluoran, 2-anilino-3-methyl-6
-Isoamylethylaminofluoran, 2- (o-chloroanilino) -6-diethylaminofluoran, 2-octylamino-6-diethylaminofluoran, 2-ethoxyethylamino-3-chloro-2-diethylaminofluoran, 2- Anilino-3-chloro-6-diethylaminofluoran, benzoylleucomethylene blue,
p-Nitrobenzyl leucomethylene blue, 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3,3'-dichloro-spiro-dinaphthopyran, 3-benzylspirodinaphthopyran, 3-propyl-spiro-dibenzopyran And the like.

Examples of the electron-accepting compound include phenol derivatives, salicylic acid derivatives, and hydroxybenzoic acid esters. Particularly, bisphenols and hydroxybenzoates are preferred. Some examples of these include 2,2-bis (p-hydroxyphenyl) propane (ie, bisphenol A), 4,4 ′-(p-phenylenediisopropylidene) diphenol (ie, bisphenol P), 2,2-bis (p-hydroxyphenyl) pentane, 2,2-bis (p-hydroxyphenyl) ethane, 2,2-bis (p-hydroxyphenyl)
Butane, 2,2-bis (4'-hydroxy-3 ', 5'
-Dichlorophenyl) propane, 1,1- (p-hydroxyphenyl) cyclohexane, 1,1- (p-hydroxyphenyl) propane, 1,1- (p-hydroxyphenyl) pentane, 1,1- (p-hydroxyphenyl) ) -2-Ethylhexane, 3,5-di (α-methylbenzyl) salicylic acid and its polyvalent metal salts, 3,5-di (tert-butyl) salicylic acid and its polyvalent metal salts, 3-α, α- Dimethylbenzyl salicylic acid and its polyvalent metal salts, butyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, p-hydroxybenzoic acid
Examples include 2-ethylhexyl, p-phenylphenol, p-cumylphenol and the like.

As the sensitizer, a low-melting point organic compound having an appropriate aromatic group and polar group in the molecule is preferable. Benzyl p-benzyloxybenzoate, α-naphthylbenzyl ether, β- Naphthyl benzyl ether,
β-naphthoic acid phenyl ester, α-hydroxy-β
-Naphthoic acid phenyl ester, β-naphthol- (p
-Chlorobenzyl) ether, 1,4-butanediol phenyl ether, 1,4-butanediol-p-methylphenyl ether, 1,4-butanediol-p-ethylphenyl ether, 1,4-butanediol-m-
Methyl phenyl ether, 1-phenoxy-2- (p-
Tolyloxy) ethane, 1-phenoxy-2- (p-ethylphenoxy) ethane, 1-phenoxy-2- (p-
Chlorophenoxy) ethane, p-benzylbiphenyl and the like.

In the present invention, use forms of the above-mentioned diazonium salt compound, a coupler, a basic substance, a colorless electron-donating dye, an electron-accepting compound, and a sensitizer which react with the diazonium salt compound to give a color when heated. Is not particularly limited. That is, (1) a method of using a solid dispersion, (2) a method of using an emulsified dispersion, (3) a method of using a polymer dispersed, (4) a method of using a latex dispersed, and (5) a micro method. Although there is a method of encapsulation and the like, among them, the method of microencapsulation is particularly preferable from the viewpoint of storage stability, and particularly in a color developing system utilizing a reaction between a diazonium salt compound and a coupler, a diazonium salt compound is used. In the case of microencapsulation, it is preferable to microencapsulate the electron donating colorless dye in a color forming system utilizing the reaction between the electron donating colorless dye and the electron accepting compound.

As a method of microencapsulation, a conventionally known microcapsule method can be used.
That is, the colorant, the additive and the microcapsule wall precursor are dissolved in a water-insoluble or insoluble organic solvent, added to an aqueous solution of a water-soluble polymer, emulsified and dispersed using a homogenizer or the like, and the temperature is raised. It can be adjusted by forming a polymer substance to be a microcapsule wall as a wall film at the oil / water interface.

Examples of the organic solvent include low-boiling auxiliary solvents such as acetate, methylene chloride, and cyclohexanone and / or phosphates, phthalates, acrylates, methacrylates, other carboxylic esters, fatty acid amides, and the like. Alkylated biphenyl, alkylated terphenyl, alkylated naphthalene,
Diarylethane, chlorinated paraffin, alcoholic,
Phenol type, ether type, monoolefin type, epoxy type and the like can be mentioned. Specific examples include tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, tricyclohexyl phosphate, dibutyl phthalate, dioctyl phthalate, dilaurate phthalate, dicyclohexyl phthalate, butyl olefin, diethylene glycol benzoate, dioctyl sebacate, Dibutyl sebacate, dioctyl adipate, trioctyl trimellitate, acetyl triethyl citrate, octyl maleate, dibutyl maleate, isoamyl biphenyl, chlorinated paraffin, diisopropyl naphthalene,
1,1'-ditolylethane, 2,4-ditertiaryamylphenol, N, N-dibutyl-2-butoxy-5
Tert-octylaniline, hydroxybenzoic acid 2-
Ethylhexyl ester, high-boiling oils such as polyethylene glycol, and among them, alcohols, phosphates, carboxylic esters,
Preferred are alkylated biphenyls, alkylated terphenyls, alkylated naphthalenes, and diarylethanes. Further, an anti-carbonizing agent such as hindered phenol or hindered amine may be added to the high boiling point oil. Further, as the oil, those having an unsaturated fatty acid are particularly desirable,
α-methylstyrene dimer and the like.
Examples of the α-methylstyrene dimer include “MSD100” (trade name, manufactured by Mitsui Toatsu Chemicals, Inc.).

As the water-soluble polymer, a water-soluble polymer such as polyvinyl alcohol is used, but a hydrophobic polymer emulsion or latex can also be used in combination. Examples of the water-soluble polymer include polyvinyl alcohol, silanol-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amino-modified polyvinyl alcohol, itaconic acid-modified polyvinyl alcohol, styrene-maleic anhydride copolymer, butadiene-maleic anhydride copolymer, and ethylene. -Maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, polyacrylamide, polystyrene sulfonic acid, polyvinylpyrrolidone, ethylene-acrylic acid copolymer, gelatin and the like, among which carboxy-modified polyvinyl alcohol is particularly preferred. preferable. Examples of the hydrophobic polymer emulsion or latex include a styrene-butadiene copolymer, a carboxy-modified styrene-butadiene copolymer, and an acrylonitrile-butadiene copolymer. At this time, a conventionally known surfactant or the like may be added as necessary.

Specific examples of the high molecular substance which forms the wall film of the microcapsule include polyurethane resin, polyurea resin, polyamide resin, polyester resin, polycarbonate resin, aminoaldehyde resin, melamine resin, and the like.
Polystyrene resin, styrene-acrylate copolymer resin, styrene-methacrylate copolymer resin, gelatin, polyvinyl alcohol and the like can be mentioned. Among these, a particularly preferred wall agent is a polyurethane / polyurea resin. Microcapsules having a wall film composed of a polyurethane / polyurea resin, a microcapsule wall precursor such as polyvalent isocyanate is mixed in a core material to be encapsulated, and emulsified and dispersed in an aqueous solution of a water-soluble polymer such as polyvinyl alcohol. It is produced by raising the liquid temperature and causing a polymer forming reaction at the oil droplet interface.

Some specific examples of the polyvalent isocyanate compound are shown below. For example, m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-
Tolylene diisocyanate, 2,4-tolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylmethane-4,4′-diisocyanate, 3,
3'-diphenylmethane-4,4'-diisocyanate, xylene-1,4-diisocyanate, 4,4'-
Diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,
Diisocyanates such as 2-diisocyanate, cyclohexylene-1,2-diisocyanate, and cyclohexylene-1,4-diisocyanate; 4,4 ′, 4 ″-
Triphenylmethane triisocyanate, toluene
Triisocyanates such as 2,4,6-triisocyanate, 4,4′-dimethylphenylmethane-2,2 ′,
Tetraisocyanates such as 5,5′-tetraisocyanate, adducts of hexamethylene diisocyanate with trimethylolpropane, adducts of 2,4-tolylenediisocyanate with trimethylolpropane, and xylylenediisocyanate with trimethylolpropane And isocyanate prepolymers such as adducts and adducts of tolylene diisocyanate and hexanetriol. If necessary, two or more kinds can be used in combination. Of these, particularly preferred are those having three or more isocyanate groups in the molecule.

In the microencapsulation method, the oil shown by emulsification and dispersion can be used as the organic solvent for dissolving the colorant, additives and microcapsule wall precursor. The same applies to a water-soluble polymer. The particle size of the microcapsules is preferably from 0.1 to 1.0 μm, more preferably from 0.2 to 0.7 μm.

In the present invention, the above-mentioned heat-sensitive recording layers may be laminated, and a multi-color heat-sensitive recording material can be obtained by changing the hue of each heat-sensitive recording layer. Although the layer configuration is not particularly limited, it is particularly preferable that the layers having different photosensitive wavelengths have different wavelengths.
Thermal recording using two types of diazonium salt compounds, two thermosensitive recording layers combining couplers that react with each diazonium salt compound when heated to develop different colors, and a thermosensitive recording layer combining an electron-donating colorless dye and an electron-accepting compound. And a multi-color thermosensitive recording material in which three layers are laminated, and three thermosensitive recording layers in which three kinds of diazonium salt compounds having different photosensitive wavelengths are combined with couplers which react with the respective diazonium salt compounds when heated to develop different colors. The multicolor heat-sensitive recording material described above is preferable, and the latter is more preferable.

In the present invention, the following known antioxidants can be used in order to further improve the light fastness. For example, EP-A-310551,
German Patent No. 3435443, European Patent No. 310552, Japanese Patent Application Laid-Open No. 3-121449.
JP-A-59-41616, JP-A-2-262654, JP-A-2-71262, JP-A-63-163351, U.S. Pat. No. 4,814,262, and JP-A-54-48535. ,
JP-A-5-61166, JP-A-5-119449
No., US Pat. No. 4,980,275, JP-A-63
JP-A-113536, JP-A-62-262047, EP-A-223239, EP-A-309402, and EP-A-309401.

Further, it is also effective to use various additives already known as heat-sensitive recording materials and pressure-sensitive recording materials. Of these, some of the antioxidants are described in JP-A-60-125470, JP-A-60-125471, JP-A-60-125472, and JP-A-60-2.
87485, JP-A-60-287486,
JP-A-60-287487, JP-A-62-146
680, JP-A-60-287488, JP-A-62-282885, JP-A-63-89877
JP, JP-A-63-88380, JP-A-63-088381, JP-A-01-239282, JP-A-04-291885, JP-A-04-2
No. 91684, Japanese Unexamined Patent Publication No. 05-188687,
JP-A-05-188686, JP-A-05-110
490, JP-A-05-1108437, JP-A-05-170361, JP-A-63-2033
No. 72, JP-A-63-2241989, JP-A-63-267594, JP-A-63-182484
JP, JP-A-60-107384, JP-A-60-107384
-107383, JP-A-61-160287, JP-A-61-185483, JP-A-61-2
No. 11079, JP-A-63-251282,
JP-A-63-051174, JP-B-48-043
No. 294, JP-B-48-033212 and the like.

Specific examples include 6-ethoxy-1-phenyl-
2,2,4-trimethyl-1,2-dihydroquinoline,
6-ethoxy-1-octyl-2,2,4-trimethyl-1,2-dihydroquinoline, 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline, 6-ethoxy-1-octyl-2,
2,4-trimethyl-1,2,3,4-tetrahydroquinoline, nickel cyclohexanoate, 2,2-bis-4
-Hydroxyphenylpropane, 1,1-bis-4-hydroxyphenyl-2-ethylhexane, 2-methyl-
4-methoxy-diphenylamine, 1-methyl-2-phenylindole.

These antioxidants can be added to the heat-sensitive recording layer or intermediate layer, the light transmittance adjusting layer, and the protective layer. When these antioxidants are used in combination, for example, specific examples (Q-7), (Q-45), (Q-4)
6) or a combination of compound (Q-10) and compound (Q-13).

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In the present invention, as the compound contained in the light transmittance adjusting layer, for example, the compounds described in JP-A-9-1928 can be used.

In the above-described example, the description has been made particularly with respect to the full-color heat-sensitive recording layer. However, the heat-sensitive recording material of the present invention may be a heat-sensitive recording material having a monocolor heat-sensitive recording layer.

The monocolor heat-sensitive recording layer contains at least a substantially colorless color-forming component A and a substantially colorless color-forming component B which reacts with the color-forming component A to form a color. The color-forming component A and the color-forming component B are components that cause a color-forming reaction when they come into contact with each other. Examples of combinations of these components include the following (A) to (W).

(A) Combination of a photodegradable diazonium salt compound and a coupler. (B) A combination of an electron-donating dye precursor and an electron-accepting compound. (C) A combination of an organic metal salt such as silver behenate and silver stearate with a reducing agent such as protocatechinic acid, spiroindane and hydroquinone. (D) A combination of a long-chain fatty acid salt such as ferric stearate and ferric myristate and a phenol such as tannic acid, gallic acid and ammonium salicylate.

(E) Organic acid heavy metal salts such as nickel, cobalt, lead, copper, iron, mercury and silver salts such as acetic acid, stearic acid and palmitic acid; and alkalis such as calcium sulfide, strontium sulfide and potassium sulfide. A combination with an earth metal sulfide or a combination of the organic acid heavy metal salt and an organic chelating agent such as s-diphenylcarbazide or diphenylcarbazone. (F) A combination of a heavy metal sulfate such as a sulfate of silver, lead, mercury or sodium and a sulfur compound such as Na-tetrathionate, sodium thiosulfate or thiourea.

(G) A combination of a ferric fatty acid salt such as ferric stearate and an aromatic polyhydroxy compound such as 3,4-hydroxytetraphenylmethane. (H) A combination of an organic acid metal salt such as oxalate and mercury oxalate and an organic polyhydroxy compound such as polyhydroxy alcohol, glycerin and glycol. (Ii) A combination of a ferric fatty acid salt such as ferric pelargonic acid or ferric laurate, and a thiocesylcarbamide or isothiocesylcarbamide derivative.

(Nu) Lead salts of organic acids such as lead caproate, lead pelargonate and lead behenate, ethylene thiourea, N
-In combination with a thiourea derivative such as dodecylthiourea. (R) A combination of a heavy metal salt of a higher fatty acid such as ferric stearate and copper stearate with zinc dialkyldithiocarbamate. (Ii) Those that form an oxazine dye, such as a combination of resorcinol and a nitroso compound. (W) A combination of a formazan compound and a reducing agent and / or a metal salt.

Among them, in the present invention, (a)
A combination of a photodegradable diazonium salt compound and a coupler,
The combination of the electron-donating dye precursor and the electron-accepting compound of (b), the combination of the organometallic salt and the reducing agent of (c) are preferable, and the cases of (a) and (b) are more preferable. Is preferred.

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EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. In the examples, “parts” means parts by weight.

Example 1 (1) Preparation of Support A wood pulp composed of 100 parts of LBKP was subjected to 300 cc Canadian freeness using a double disc refiner.
Beated until 0.5 part of epoxidized behenamide, 1.0 part of anionic polyacrylamide, 0.1 part of polyamide polyamine epichlorohydrin, and 0.5 part of cationic polyacrylamide were added at an absolute dry weight ratio to pulp, A base paper having a basis weight of 100 g / m ² is formed by a fourdrinier paper machine, the surface size of polyvinyl alcohol is set to an absolute dry weight of 1.0 g / m ² , and a density of 1.0 is obtained by calendering.
Was adjusted.

After performing a corona discharge treatment on the wire surface (back surface) side of the base paper, high-density polyethylene was coated to a resin thickness of 30 μm using a melt extruder to form a resin layer having a matte surface ( This surface is called the back surface). After the corona discharge treatment on the polyethylene coated surface of the back surface, aluminum oxide (“Alumina Sol 100” manufactured by Nissan Chemical Industries, Ltd.) / Silicon dioxide (“Snowtex O” manufactured by Nissan Chemical Industries, Ltd.) as an antistatic agent = 1 /
2 (weight ratio) dispersed in water and dried to a weight of 0.2 g
/ M ² . (This is called the back PE lami product)

Further, a corona discharge treatment is performed on the felt surface (front surface) side of the base paper, and a low-density polyethylene containing 10% by weight of titanium dioxide and a very small amount of ultramarine is made to have a resin thickness of 40 μm using a melt extruder. Melt extrusion coating was performed to form a resin layer having a glossy surface (this surface is referred to as a front surface). After the corona discharge treatment on the front side of the polyethylene-coated surface, the gelatin undercoat was dried at a weight of 0.1%.
g / m ² . Hereinafter, a production example of a thermosensitive recording material according to the present invention capable of reproducing three colors of yellow, magenta, and cyan independently and reproducing a full-color image will be described.

(2) Preparation of Undercoat Layer Liquid Swellable synthetic mica (manufactured by Corp Chemical Co .; "Somasif ME
100 "), 97.5 parts of water was added to 2.5 parts, and the mixture was dispersed with a dynamill. This was added to 200 parts of a 5% by weight aqueous solution of gelatin at 40 ° C., stirred for 30 minutes, and 20 parts of the following surfactant-1 (5% by weight) was added to obtain an undercoat layer solution.

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(3) Preparation of Cyan Thermosensitive Recording Layer Solution <Preparation of Capsule Solution Containing Electron Donating Dye Precursor> Solution A Solution 3- (o-methyl-p-dimethylaminophenyl) -3
5 parts of-(1'-ethyl-2'-methylindol-3-yl) phthalide (electron-donating dye precursor) are dissolved in 20 parts of ethyl acetate, and 20 parts of alkylnaphthalene (high boiling point solvent) is added thereto. Add and heat to mix evenly.
To the obtained solution, 20 parts of a 1/3 adduct of xylylene diisocyanate / trimethylolpropane was added, and the mixture was stirred uniformly to prepare solution A. Solution B Liquid B was prepared by adding 2 parts by weight of a 2% by weight aqueous solution of sodium dodecylsulfonate to 54 parts of a 6% by weight aqueous solution of phthalated gelatin.

Solution A was added to solution B, and the mixture was emulsified and dispersed using a homogenizer to obtain an emulsified dispersion. 68 parts of water is added to the obtained emulsified dispersion, mixed and homogenized, and then the mixture is heated to 50 ° C. while stirring to encapsulate the microcapsules so that the average particle diameter of the microcapsules becomes 1.2 μm. The reaction was performed for 3 hours to obtain a capsule liquid.

<Preparation of developer emulsified dispersion> 1,1- (p
-Hydroxyphenyl) -2-ethylhexane (developer) 2.5 parts, tricresyl phosphate 0.3 part and diethyl maleate 0.1 part were dissolved in ethyl acetate 10 parts. The obtained solution was added to a solution obtained by mixing 20 parts of a 6% by weight aqueous solution of gelatin and 2 parts of a 2% by weight aqueous solution of sodium dodecyl sulfonate, and emulsified for 10 minutes using a homogenizer to obtain an emulsified dispersion. .

<Preparation of Coating Solution> SBR latex (manufactured by Sumitomo Nogatack; "SN-307") was added to the capsule solution containing the electron-donating dye precursor prepared above at 40% by weight based on the solid content of the capsule. Thereafter, the developer emulsified dispersion was mixed with the capsule liquid containing the electron-donating dye precursor so that the weight ratio became 1/4 to obtain a cyan layer coating liquid.

(4) Preparation of Magenta Thermosensitive Recording Layer Solution <Preparation of Capsule Solution Containing Diazo Compound> 2.0 parts of diazo compound (1) (decomposed by light having a wavelength of 365 nm) represented by the following structural formula was dissolved in acetic acid. After dissolving in 20 parts of ethyl,
Further, 20 parts of alkylnaphthalene was added, and the mixture was heated and uniformly mixed. To the resulting solution, 15 parts of an adduct (capsule wall material) of xylylene diisocyanate / trimethylolpropane 1/3 was added and mixed uniformly to obtain a diazo compound solution. The obtained solution of the diazo compound was added to a solution obtained by mixing 54 parts of a 6% by weight aqueous solution of phthalated gelatin and 2 parts of a 2% by weight aqueous solution of sodium dodecyl sulfonate, and emulsified and dispersed using a homogenizer. 68 parts of water was added to the obtained emulsified dispersion, mixed uniformly, and heated to 40 ° C. with stirring, so that the average particle diameter of the capsule was 1.2 μm.
The encapsulation reaction was performed for 3 hours to obtain a capsule solution.

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<Preparation of Coupler Emulsion Dispersion> 2 parts of coupler (1) represented by the following structural formula, 2 parts of 1,2,3-triphenylguanidine, and tricresyl phosphate 0.3
Parts and 0.1 part of diethyl maleate were dissolved in 10 parts of ethyl acetate. The obtained solution was poured into an aqueous solution obtained by mixing 20 parts of a 6% by weight aqueous solution of gelatin and 2 parts of an aqueous solution of 2% by weight of sodium dodecylsulfonate, and then emulsified for 10 minutes using a homogenizer to obtain an emulsified dispersion. Was.

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<Preparation of Coating Solution> SBR latex (manufactured by Sumitomo Nogatack; "SN-307") was added to the capsule solution containing the diazo compound prepared above in an amount of 40% by weight based on the solid content of the capsule. The emulsified liquid was mixed at a weight ratio of 3/2 with respect to the capsule liquid containing the diazo compound to obtain a magenta layer coating liquid.

(5) Preparation of yellow thermosensitive recording layer liquid <Preparation of capsule liquid containing diazo compound>
Dibutoxy-4-tolylthiobenzenediazonium hexafluorophosphate (diazo compound: 420 nm
3.0 parts were dissolved in 20 parts of ethyl acetate, and alkylnaphthalene 2 was added as a high boiling point solvent.
0 parts were added and mixed by heating. Xylylene diisocyanate / capsule wall solution was added to the obtained solution.
15 parts of a 1/3 adduct of trimethylolpropane was added and mixed uniformly to obtain a diazo compound solution. A solution of the obtained diazo compound was added to 6% by weight of phthalated gelatin.
54 parts of aqueous solution and sodium dodecyl sulfonate aqueous solution 2
The mixture was added to the mixed solution, and emulsified and dispersed using a homogenizer. 68 parts of water was added to the obtained emulsified dispersion,
The uniformly mixed solution was heated to 40 ° C. while further stirring, and an encapsulation reaction was performed for 3 hours so that the average particle diameter of the capsules was 1.3 μm, to obtain a capsule solution.

<Preparation of Coupler Emulsion Dispersion> 2 parts of 2-chloro-5- (3- (2,4-di-tert-pentyl) phenoxypropylamino) acetoacetanilide,
1 part of 1,2,3-triphenylguanidine, 0.3 part of tricresyl phosphate and 0.1 part of diethyl maleate
Parts in 10 parts of ethyl acetate, 6% by weight of gelatin
The mixture was poured into an aqueous solution obtained by mixing 20 parts of an aqueous solution and 2 parts of a 2% by weight aqueous solution of sodium dodecylsulfonate, and emulsified for 10 minutes using a homogenizer to obtain an emulsified dispersion.

<Preparation of Coating Liquid> The coupler emulsified dispersion prepared above was mixed with the capsule liquid containing the diazo compound so that the weight ratio thereof was 3/2 to obtain a coating liquid for a yellow layer.

(6) Preparation of Intermediate Layer Solution Gelatin (manufactured by Nitta Gelatin Co., Ltd .; trade name “# 75”)
0 ") Polyacrylic acid (manufactured by Nippon Pure Chemical Co., Ltd .; trade name" Julima AC-10L ") in 10 parts of a 15% by weight aqueous solution
3 parts by weight of a 15% by weight aqueous solution and 5 parts by weight of a 4% by weight aqueous solution of boric acid were added and uniformly mixed to obtain an intermediate layer liquid.

(7) Preparation of Coating Solution for Light Transmittance Adjusting Layer 1.5 parts of the compound shown below and R-6 as a reducing agent were added in 0.1 part.
5 parts, ethyl acetate 6.0 parts and tricresyl phosphate 0.8
And thoroughly dissolved. Xylylene diisocyanate / trimethylolpropane (7
5% ethyl acetate solution: Takeda Pharmaceutical Co .;
10N ") was added to this solution and stirred until uniform. 29.7 parts of an aqueous solution of 8% by weight of carboxy-modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd .; "KL-318") was prepared, added to the above solution, and emulsified and dispersed by a homogenizer. The obtained emulsion was added to 40 parts of ion-exchanged water and stirred at 40 ° C. for 3 hours to perform an encapsulation reaction. Thereafter, 7.0 parts of an ion exchange resin “Amberlite MB-03” (manufactured by Organo) was added, and the mixture was further stirred for 1 hour and filtered to prepare a target coating solution. The average particle size of the capsule was 0.35 μm.

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(8) Preparation of Protective Layer Solution Gelatin (15% by weight) 20g Water 50g Cymac US450 (30% by weight) 25g (Silicone graft polymer; manufactured by Toagosei Co., Ltd.) VARIFINE BF21 dispersion (20% by weight) 7 g (barium sulfate ultrafine particles; manufactured by Sakai Chemical Industry Co., Ltd.) Snowtex C (20% by weight) 5 g (colloidal silica; manufactured by Nissan Chemical Industries, Ltd.) Surfactant-1 (2% by weight) 3 ml Surfactant-2 (5 Weight%) 3 ml Surflon S-131 (30 weight%) 0.5 ml (fluorinated surfactant; manufactured by Asahi Glass Co., Ltd.)

[0117]

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(9) Production of Thermal Recording Material 100 (Comparative Example)
On the front side of a paper support laminated with polyethylene,
In order from the support, an undercoat layer solution, a cyan thermosensitive recording layer solution, a medium
Interlayer liquid, magenta thermosensitive recording layer liquid, intermediate layer liquid, yellow feeling
Becomes a thermal recording layer liquid, light transmittance adjusting layer liquid, and protective layer liquid
Multi-layer heat-sensitive recording material 100
I got The amount of coating is equivalent to the solid content after drying.
1.0 g / m ^TwoThe cyan thermosensitive recording layer
6.1 g / m^Two, The intermediate layer is 1.0 g / m^Two, Magenta feeling
Thermal recording layer is 7.8 g / m^Two, The intermediate layer is 1.0 g / m^Two,
7.2 g / m of yellow heat-sensitive recording layer^Two, Light transmittance adjustment layer
Is 1.5 g / m^Two, And the protective layer is 1.2 g / m ^Twoage
Was.

(10) Preparation of Thermosensitive Recording Material 101 In the preparation of the coating solution for the light transmittance adjusting layer of the thermosensitive recording material 100, finally, an aqueous dispersion (2) of swellable synthetic mica “ME100” (manufactured by Corp Chemical Co., Ltd.) (0.5% by weight), and a heat-sensitive recording material 101 was prepared in the same manner as the heat-sensitive recording material 100 except that the mixture was stirred for about 30 minutes.

(11) Preparation of heat-sensitive recording material 102 The amount of boric acid added to the intermediate layer coating solution between the magenta heat-sensitive recording layer and the cyan heat-sensitive recording layer of the heat-sensitive recording material 100 was doubled, and the magenta heat-sensitive recording layer and the yellow heat-sensitive A heat-sensitive recording material 102 was prepared in the same manner as the heat-sensitive recording material 100, except that the coating liquid for the intermediate layer between the recording layers was as described below, and the coating amount of the intermediate layer was 1.5 g / m ² .

(Preparation of Coating Solution for Intermediate Layer) While stirring 200 parts of an 8% by weight aqueous solution of KL-318 at 40 ° C., 50 parts of a 2.5% by weight dispersion of a swellable synthetic mica “ME100” was added little by little. This was added to obtain an intermediate layer coating liquid.

The heat-sensitive recording materials 100 to 100 obtained in Example 1
102 was evaluated as follows. [Gloss] Using a TA printer (printer for full-color thermal recording material) NC301D (manufactured by Fuji Photo Film Co., Ltd.), solid printing was performed so that the gray density D ≒ 1.0.
The specular reflection at 20 ° incidence was measured with a gloss meter. [Light fastness] A sample solid-printed on the heat-sensitive recording material using NC301D such that the coloring density of each of the yellow, magenta, and cyan coloring layers becomes D ≒ 1.0,
A sample subjected to light fixing alone (for background light resistance) was prepared and irradiated with light for 120 hours using a fluorescent lamp fading tester (20,000 lux). The densities of yellow, magenta, and cyan before and after irradiation were measured with a Macbeth densitometer, and the residual dye ratio (%) and light stain were calculated as follows.

[0123]

(Equation 1)

Table 1 shows the above results.

[Table 1]

[0125]

As described above, according to the heat-sensitive recording material of the present invention, the color image and the background (white background) can be maintained while maintaining the glossiness.
A heat-sensitive recording material having excellent light fastness can be provided.

Claims (6)

[Claims] 1. A heat-sensitive recording material having a heat-sensitive recording layer and a protective layer on a support, wherein the protective layer contains a silicone-modified polymer, and any one of the layers of the heat-sensitive recording material contains a swellable inorganic layered compound. A heat-sensitive recording material characterized in that: 2. The heat-sensitive recording material according to claim 1, wherein the protective layer contains a silicone-modified polymer and gelatin. 3. The heat-sensitive recording material according to claim 1, wherein the support has oxygen barrier properties. 4. A second protective layer or a light transmittance adjusting layer is provided between the heat-sensitive recording layer and the protective layer, and a swellable inorganic layer compound is added to the second protective layer or the light transmittance adjusting layer. The heat-sensitive recording material according to any one of claims 1 to 3, wherein the heat-sensitive recording material is contained. 5. The heat-sensitive recording layer has two or more heat-sensitive recording layers and an intermediate layer between these heat-sensitive recording layers, and an intermediate layer on the heat-sensitive recording layer having the lowest light fastness. The heat-sensitive recording material according to any one of claims 1 to 4, wherein the layer contains a swellable inorganic layered compound. 6. The heat-sensitive recording material according to claim 1, wherein the glass transition temperature (Tg) of the silicone-modified polymer is 60 ° C. or higher.