JP2001199164A - Recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording matezial, which can prevent cracks from developing during a storage under lowly humid conditions or the like while curlings are prevented from occurring. SOLUTION: In the recording material having at least an image recording layer and a protective layer on a support, the total coated dry thickness in the image recording layer side is made thicker than 15 μm and a swelling inorganic lamellar compound. Or, in the recording material having at least the image recording layer and the protective layer on the support, a second protective layer is provided between the image recording layer and the protective layer under the conditions that the total coated dry thickness in the image recording layer side is made thicker than 15 μm and the swelling inorganic lamellar compound is included in the second protective layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material, and more particularly to a recording material suitable for preventing cracks in an image recording layer and a protective layer under low humidity.

[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 of 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. In addition, a light transmittance adjusting layer may be provided between the heat-sensitive recording layer and the protective layer in order to enhance the light fixing property.

In some of such heat-sensitive recording materials, the coating layer formed on the heat-sensitive recording layer side of the support has a thickness of 15 μm or more. When a bending force is applied to the steel, cracks are likely to occur. In particular, the tendency is large in a heat-sensitive recording material containing a solid dispersion or microcapsules in the recording layer and a heat-sensitive recording material containing a pigment in the protective layer.

[0004]

The present inventor has disclosed in Japanese Patent Application Laid-Open
JP-A-282112 discloses that curling toward the surface side can be prevented by adding a swellable inorganic layered compound to the back layer of the heat-sensitive recording material. However, subsequent research has found that curling on both the front layer side and the back layer side can be suppressed even when a swellable inorganic layered compound is used for the protective layer or the second protective layer. Accordingly, it is an object of the present invention to provide a recording material that is less likely to crack even when stored under low humidity conditions while preventing curling.

[0005]

SUMMARY OF THE INVENTION The above-mentioned object is achieved by (1)
In a recording material having at least an image recording layer and a protective layer on a support, the total coating dry thickness on the image recording layer side is 1
A recording material having a thickness of 5 μm or more, wherein the protective layer contains a swellable inorganic layered compound; and (2) at least an image recording layer and a protective layer, and the image recording layer and the protective layer on a support. In the recording material having the second protective layer between the coating layer and the image recording layer, the total coating dry thickness on the image recording layer side is 15 μm.
m or more, wherein the recording material is characterized in that the first protective layer contains a swellable inorganic layered compound. In the recording material of (2), in particular, the image recording layer is different from the heat-sensitive recording layer (A) containing an electron-donating colorless dye and an electron-accepting compound with a maximum absorption wavelength of 360 ± 20 nm.
Heat-sensitive recording layer (B) containing a diazonium salt compound and a coupler which reacts with the diazonium salt compound when heated to form a color, a diazonium salt compound having a maximum absorption wavelength of 400 ± 20 nm, and a thermosensitive recording layer (B). A heat-sensitive recording layer (C) containing a coupler that reacts to produce a color, wherein the second protective layer is a light transmittance adjusting layer provided on the heat-sensitive recording layer, A color thermosensitive recording material containing a swellable inorganic layered compound is preferred. Further, in the recording material of (2), the image recording layer is a heat-sensitive recording layer containing a diazonium salt compound having a maximum absorption wavelength of 340 ± 20 nm and a coupler which reacts with the diazonium salt compound when heated to form a color. (D), a heat-sensitive recording layer (E) containing a diazonium salt compound having a maximum absorption wavelength of 360 ± 20 nm and a coupler which reacts with the diazonium salt compound when heated to form a color, and a maximum absorption wavelength of 400 ± 20 nm. And a heat-sensitive recording layer (F) containing a coupler that reacts with the diazonium salt compound when heated to form a color, wherein the second protective layer is provided on the heat-sensitive recording layer. A color thermosensitive recording material, which is a rate adjusting layer and contains the swellable inorganic layered compound in the light transmittance adjusting layer, is preferred.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described. (1) The recording material of the present invention comprises at least an image recording layer and a protective layer on a support, or (2) at least an image recording layer and a protective layer, and the image recording layer and the protective layer on a support. Wherein the total coating dry thickness on the image recording layer side is 15 μm or more. This total coating dry thickness is the total coating dry thickness of each layer formed on the image recording layer side, and therefore does not include the thickness of the back coat layer formed on the back surface of the support.

The total coating dry thickness on the image recording layer side is 15 μm
In the above recording material, especially the heat-sensitive recording material, when stored under low humidity conditions, when a bending force is applied to the recording material,
Although cracking is likely to occur, such a phenomenon is unlikely to occur in the recording material of the present invention. (1) In the recording material, the protective layer contains a swellable inorganic layered compound,
(2) In the recording material, the second protective layer contains a swellable inorganic layered compound.

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 preventing cracking and curling. Particle size of the water-swellable synthetic mica used in the present invention,
The average major axis is 0.3-20 μm, preferably 0.5-
It is 10 μm, particularly preferably 1 to 5 μm. The average thickness of the particles is 0.1 μm or less, preferably 0.05 μm.
μm or less.

The amount of the swellable inorganic layered compound, particularly the water-swellable synthetic mica, used in the protective layer (including the second protective layer) is from 1 to 40% by weight based on the amount of the binder.
Preferably 1.5 to 30% by weight, more preferably 2/2
0% by weight. If the amount of the swellable inorganic layered compound in the protective layer is less than 1% by weight, the expected effect of preventing cracking of the present invention is not obtained, and if it exceeds 40% by weight, the gloss may be reduced.

Further, the protective layer may contain ultrafine inorganic particles. The inorganic ultrafine particles are 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 or less. Is preferably 0.5 μm or less, more preferably 0.4 μm or less, and particularly preferably 0.35 μm or less. Further, the frequency of (aggregated) particles having a particle diameter of 0.35 μm or more in the dispersion is 5% or less, preferably 1% or less.
It is particularly preferred that the frequency of (aggregated) particles of 25 μm or more is 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, inorganic ultrafine particles of barium sulfate, zinc oxide, magnesium oxide, lead oxide, zirconium oxide, colloidal silica, or alumina are preferable. Among them, barium sulfate, colloidal silica, zirconium oxide, and alumina are preferable. Is particularly preferred.

The above-mentioned 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 protective layer of the inorganic ultrafine particles
Is added to the binder in an amount of 10 to 100% by weight,
Preferably it is 20 to 60% by weight. Addition of inorganic ultrafine particles
10% by weight If less, the effect of adding inorganic ultra-fine particles
Fruits are insufficient and 1 g / m^Two If it exceeds, the gloss decreases
May be.

As a method of blending the inorganic ultrafine particles with the coating solution for forming the protective layer of the present invention, in order to prevent agglomeration of the fine particles and to achieve uniform adsorption on the surface of the resin particles, Carboxymethylcellulose, gelatin, a method of blending as a resin solution with an aqueous dispersion resin such as polyvinyl alcohol, a method of blending after preparing a colloidal dispersion with various mills and the like, and the like, are preferred from the viewpoint of effects and production. .

The binder in the protective layer includes, for example, silicone-modified polymer, gelatin, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, starch, agar, κ-carrageenan, gum arabic, casein, styrene-maleic anhydride copolymer Hydrolysates, ethylene-maleic anhydride copolymer hydrolysates, isobutylene-maleic anhydride copolymer hydrolysates, polyvinyl alcohol-based compounds such as polyvinyl alcohol and modified polyvinyl alcohol, alkyl ether-modified polyvinyl alcohol, polyacrylamide, etc. Is mentioned. Above all, alkyl ether-modified polyvinyl alcohol described in Japanese Patent Application No. 10-297396 filed by the present inventors is preferable, and other binders described above may be used in combination as needed.

When the above-mentioned alkyl ether-modified polyvinyl alcohol is used, the alkyl groups are easily oriented on the surface of the protective layer, and the surface reduces the dynamic friction coefficient of the thermal head to reduce printing failures, and at the same time, smoothes the printing screen. Properties (glossiness) and color density can be improved. Further, when the coefficient of static friction on the surface of the protective layer is reduced, the running property of a medium such as a heat-sensitive recording material when recording with a printer or the like can be improved. Furthermore, the alkyl ether-modified polyvinyl alcohol exhibits not only the characteristics of light resistance and film strength, which are characteristics of the polyvinyl alcohol system, but also contributes to the improvement of water resistance due to the orientation of hydrophobic groups on the surface.

The content of the alkyl ether-modified polyvinyl alcohol in the protective layer is preferably at least 50% by weight based on the total weight of the binder in the protective layer.
80% by weight or more is more preferable. If the content is less than 50% by weight, the above-mentioned properties may not be sufficiently obtained due to the use of the alkyl ether-modified polyvinyl alcohol.

The aqueous binder used for the protective layer includes:
Silicone modified polymers are also preferred. Examples of the silicone-modified polymer include a silicone graft polymer, a silicone block polymer, a silicone-modified acrylic polymer, and a silicone-modified polyvinyl alcohol. Further, among the above, a silicone graft polymer is preferable, and as the silicone graft polymer, a silicone graft acrylic polymer and a silicone graft modified polyvinyl alcohol are preferable. That is, as the characteristics of the trunk polymer constituting the silicone-modified polymer, any polymer having excellent Tg (glass transition point) excellent in film forming property, heat resistance, light resistance, and film strength is used. Resins may be used, but among them, acrylic resins and polyvinyl alcohol resins are particularly preferable. Patent application No. 9-8305 filed by the present inventors
Specific examples of the silicone-modified polymer described in No. 2 can be suitably used in the present invention.

The Tg (glass transition point) of the silicone-modified polymer is preferably 60 ° C. or higher, more preferably 80 ° C. or higher, and most preferably 100 ° C. or higher. The Tg
If the (glass transition point) is less than 60 ° C., the lubricity with the head during printing may be reduced.

The content of the silicone-modified polymer in the binder of the protective layer is preferably 5 to 100% by weight, more preferably 50 to 90% by weight. If the content is less than 5% by weight, the above-mentioned properties of the silicone-modified polymer, that is, heat resistance, light resistance, and film strength may not be sufficiently obtained.

Like the above-mentioned other aqueous binder components, a water-soluble polymer which can be set and dried is preferable in that it has a high surface smoothness in the background portion and the printing surface and is excellent in glossiness. The set-dryable water-soluble polymer exhibits a predetermined viscosity when heated (for example, around 40 ° C.) and can be applied, and then cools (for example, 5 ° C. to 15 ° C.) to increase the viscosity and the fluid state. Means a water-soluble polymer that stops and gels.

Among them, gelatin is particularly preferred in that it has excellent compatibility with the silicone-modified polymer. When gelatin and silicone-modified polymer are used, the ratio (silicone-modified polymer / gelatin) is preferably 50/50 to 90/10 by weight.

When the polyvinyl alcohol-based compound is used among the aqueous binders, silanol-modified polyvinyl alcohol is preferable from the viewpoint of compatibility with the silicone-modified polymer, and the silanol-modified polyvinyl alcohol is a gelling agent. When used in combination with boric acid or 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 by weight, and 50/50 to 90/1.
0 is more preferred.

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, the formation of a protective layer is facilitated. In the case of a protective layer formed by such a method, a silicone-modified polymer having a relatively high Tg (glass transition point) tends to be oriented near the surface of the protective layer. Therefore, on the surface side of the protective layer, the hardness is high, and it is possible to prevent sticking and scumming of the thermal recording head and the like, and to impart a smoothing effect to the surface of the protective layer by the thermal recording head and the like. It is possible to enhance the color density without a printing failure, with good head followability.

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

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

Examples of the crosslinking agent include vinyl sulfone compounds, aldehyde compounds (formaldehyde, glutaraldehyde, dialdehyde starch, etc.), epoxy compounds, oxazine compounds, triazine compounds, and JP-A-62-234157. The polymer hardener, methylated melamine, blocked isocyanate, methylol compound, carbodiimide resin, and the like described in JP-A No. 2000-216, can be used. Among them, vinyl sulfone compounds, aldehyde compounds, epoxy compounds, oxazine compounds, triazine compounds, and JP-A-62-234.
The polymer hardener described in JP-A-157-157 is suitable.

Among the modified polyvinyl alcohols,
In particular, silanol-modified polyvinyl alcohol is preferred,
This can itself improve the water resistance and the like, and for the purpose of further improving the water resistance, it is effective to use a crosslinking agent and a catalyst for accelerating the reaction together with the silanol-modified polyvinyl alcohol.

Further, in addition to the above-mentioned components, pigments, lubricants, surfactants, matting agents and the like can be added to the protective layer, and organic pigments and inorganic pigments can be used as pigments. Examples of the lubricant include silicone oil and wax. In the case of water-insoluble, the silicone can be added as an emulsion, and in the case of water-soluble, it can be used by directly blending it with a coating solution.

The wax is a compound which is in a solid state at room temperature and has a melting point of 30 to 200 ° C., and any of a natural wax and a synthetic wax can be suitably used. As the above-mentioned natural wax and synthetic wax, those similar to those usable for the solid dispersion described above can be used. Among them, those having a melting point of 50 to 150 ° C are preferable.

Examples of the matting agent include fine particles such as starch obtained from barley, wheat, corn, rice, and beans, cellulose fiber, polystyrene resin, epoxy resin, and the like.
Polyurethane resin, urea formalin resin, poly (meth)
Acrylate resin, polymethyl (meth) acrylate resin, copolymer resin such as vinyl chloride or vinyl acetate, fine particles of synthetic polymer such as polyolefin, calcium carbonate,
Titanium oxide, kaolin, aluminum hydroxide, silica,
Examples include fine particles of inorganic substances such as zinc oxide. The matting agent may be used alone or in combination of two or more.

The coating liquid for the protective layer is applied on the heat-sensitive recording layer using a bar coater, an air knife coater, a blade coater, a curtain coater or the like, and dried to obtain the protective layer of the present invention. However, the protective layer may be applied at the same time as the recording layer, or the thermal recording layer may be dried once after the application of the thermal recording layer, and then applied thereon. Dry coating amount of the protective layer is preferably from 0.1 to 3 g / m ^2, more preferably from 0.3 to 2.0 g / m ^2. If the coating amount is large, the thermal sensitivity is remarkably lowered, and if the coating amount is too low, the function as a protective layer (friction resistance, lubricity, scratch resistance, etc.) cannot be exhibited. After the application of the protective layer, a calendering treatment may be performed if necessary.

Next, in the recording material of the present invention, the intermediate layer between the image recording layer and the protective layer contains a swellable inorganic layered compound. As the intermediate layer, for example, in the case of an intermediate layer formed between two or more recording layers and a protective layer, particularly, in the case of a full-color heat-sensitive recording layer, it is optically fixed to a light-fixing type heat-sensitive recording layer on a support. In a thermosensitive recording material having a light transmittance adjusting layer in which light transmittance in a wavelength region decreases after fixing, and a protective layer thereon, the light transmittance adjusting layer may contain a swellable inorganic layered compound. it can.

In the present invention, the amount of the swellable inorganic layered compound contained in the light transmittance adjusting layer as the intermediate layer is as follows:
1 to 10 with respect to the binder in the light transmittance adjusting layer
0% by weight, preferably 2 to 50% by weight, more preferably 3 to 30% by weight. If the amount of the swellable inorganic layered compound is less than 1% by weight, the expected effect of preventing cracking of the present invention is low, and if it is more than 100% by weight, the surface smoothness is reduced and the gloss is deteriorated. There is.

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 an area necessary for fixing. Since it does not function as an ultraviolet absorber before irradiation with light having a wavelength of, the light transmittance is high, and when fixing the light-fixing type thermosensitive recording layer, the wavelength in the region required for fixing is sufficiently transmitted, and The transmittance is high, and there is no problem in fixing the heat-sensitive recording layer.

The precursor of the ultraviolet absorber is converted into an ultraviolet absorber by reacting with light or heat after light irradiation of a wavelength necessary for fixing of 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. The characteristics of the light transmittance adjusting layer can be arbitrarily selected according to the characteristics of the light fixing type thermosensitive recording layer.

The aqueous polymer used for the second protective layer of the present invention is not particularly limited, and an aqueous polymer such as a polyvinyl alcohol-based, polyamide-based, or polymer having an amide group and a carboxyl group can be used. 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 second protective layer containing a swellable inorganic layered compound, particularly a water-swellable synthetic mica, does not deteriorate the transparency of the layer and has a good barrier property against a color-forming substance. The same barrier performance is obtained at a thickness of 5 to 45% of the thickness of the second protective layer made of only a binder such as a water-soluble polymer. That is, by increasing the barrier performance, the thickness of the second protective layer can be reduced, and the sharpness, sensitivity (printing speed), and curling resistance of the recording material can also be improved.

The image-recording layer of the present invention may be a monocolor heat-sensitive recording layer, but is preferably a full-color heat-sensitive recording layer, and further comprises a coupler and a binder which have a coupling reaction with a diazonium salt compound on a support. It is desirable to have at least one thermosensitive recording layer. 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 (second protective layer) containing a swellable inorganic layered compound and an outermost protective layer on the layer.

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.

The image recording layer comprises a heat-sensitive recording layer (A) containing an electron-donating colorless dye and an electron-accepting compound; a diazonium salt compound having a maximum absorption wavelength of 360 ± 20 nm; A heat-sensitive recording layer (B) containing a coupler which develops a color when reacting,
A diazonium salt compound having a diameter of 00 ± 20 nm, and a thermosensitive recording layer (C) containing a coupler which reacts with the diazonium salt compound when heated to form a color, wherein the second protective layer is provided on the thermosensitive recording layer. Light transmittance adjusting layer,
The heat-sensitive recording material containing the swellable inorganic layered compound in the light transmittance adjusting layer and the image recording layer have a maximum absorption wavelength of 34.
A heat-sensitive recording layer (D) containing a diazonium salt compound having a wavelength of 0 ± 20 nm, a coupler which reacts with the diazonium salt compound when heated to form a color, and a maximum absorption wavelength of 360 ± 20 n
m, a thermosensitive recording layer (E) containing a coupler which reacts with the diazonium salt compound when heated to give a color, and a diazonium salt compound having a maximum absorption wavelength of 400 ± 20 nm and the diazonium salt compound. A heat-sensitive recording layer (F) containing a coupler that reacts with heat to form a color, wherein the second protective layer is a light transmittance adjusting layer provided on the image recording layer; A heat-sensitive recording material containing a swellable inorganic layered compound in the adjustment layer is particularly preferred.

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 preferred. 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.

[0046]

Embedded image

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.

[0049]

Embedded image

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).

The coupler which reacts with the above-mentioned diazonium salt at the time of heating to produce a color includes 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.

[0052]

Embedded image

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-naphthyl benzyl 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 polymer substance serving as the wall film of the microcapsules include, for example, polyurethane resin, polyurea resin, polyamide resin, polyester resin, polycarbonate resin, aminoaldehyde resin, melamine resin, polystyrene resin, styrene-acrylate copolymer resin, Styrene-methacrylate copolymer resin, gelatin, polyvinyl alcohol, and the like. 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 following known antioxidants can be used in order to further improve the light resistance. 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).

[0067]

Embedded image

[0068]

Embedded image

[0069]

Embedded image

[0070]

Embedded image

[0071]

Embedded image

[0072]

Embedded image

[0073]

Embedded image

As the support in the present invention, a plastic film, paper, plastic resin laminated paper, synthetic paper, or the like can be used.

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 these, 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.

In the present invention, when a support having a high oxygen permeability such as a laminated paper is used, an undercoat layer may be provided as an oxygen-blocking layer to improve light resistance.
A water-soluble polymer compound is used for the undercoat layer. For example, polyvinyl alcohol, modified polyvinyl alcohol,
Examples include methylcellulose, sodium polystyrene sulfonate, styrene-maleic acid copolymer, and gelatin.

In the above, an example of a heat-sensitive recording material has been described as a recording material. However, in addition to the heat-sensitive recording material of the present invention, a silver halide light-sensitive material other than the heat-sensitive recording material may be used. Those having a thickness of 15 μm or more are also included,
Also in this case, cracks and the like during storage under low humidity conditions can be prevented.

[0083]

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 side (back 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 composed of a mat 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 applied to 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 Solution 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.

[0088]

Embedded image

(3) Preparation of Cyan Thermosensitive Recording Layer Solution <Preparation of Capsule Solution Containing Electron Donating Dye Precursor> Solution A 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 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) represented by the following structural formula (decomposed by light having a wavelength of 365 nm) 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.

[0094]

Embedded image

<Preparation of Coupler Emulsion Dispersion> 2 parts of coupler (1), 2 parts of 1,2,3-triphenylguanidine, and tricresyl phosphate 0.3 represented by the following structural formula
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.

[0096]

Embedded image

<Preparation of Coating Solution> SBR latex (manufactured by Sumitomo Nogatack; "SN-307") was added to the capsule solution containing the diazo compound prepared above at 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 Solution <Preparation of Capsule Solution 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 Solution> The previously prepared coupler emulsified dispersion was mixed with the capsule solution containing the diazo compound so that the weight ratio thereof was 3/2, to obtain a coating solution for 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 were added and mixed uniformly to obtain an intermediate layer liquid.

(7) Preparation of Coating Solution for Light Transmittance Adjusting Layer 1.5 parts of the compound shown below, R-6 was added as a reducing agent 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 Corporation) was added, and the mixture was further stirred for 1 hour. Thus, a target coating solution was prepared. The average particle size of the capsule is 0.35 μm
Met.

[0103]

Embedded image

(8) Preparation of Protective Layer Solution EP130 (7% by weight) 100g Water 50g Varifine BF21 dispersion (20% by weight) 10g Surfactant-1 (2% by weight) 5ml Surfactant-2 (5 5% by weight) "EP130" Dodecyl-modified polyvinyl alcohol manufactured by Denki Kagaku Kogyo Co., Ltd., and "Varifine BF21 Dispersion" are barium sulfate ultrafine particles manufactured by Sakai Chemical Industry Co., Ltd. The above-mentioned surfactant-2 is represented by the following structural formula.

[0105]

Embedded image

(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, 2.5% by weight of a swellable synthetic mica “ME100” (manufactured by Corp Chemical) was dispersed. Except that 50 parts of a liquid (dispersed in the same manner as in the preparation of the undercoat layer liquid) was added, and the coating amount of the light transmittance control layer was 1.7 g / m ^{2 in} terms of solid content.
Thermal recording material 1 in the same manner as thermal recording material 100
01 was produced.

(11) Preparation of Thermosensitive Recording Material 102 In the preparation of the protective layer solution of the thermosensitive recording material 100, the swellable synthetic mica “ME100” (manufactured by Corp Chemical Co.) was used.
A heat-sensitive recording material 102 was prepared in the same manner as in the case of the heat-sensitive recording material 100 except that 40 g of the 5 wt% dispersion was used.

The heat-sensitive recording materials 100 to 100 obtained in Example 1
102 was evaluated as follows. [Crack test] A thermosensitive recording material (sample) cut to a width of 3 cm and a length of 20 cm was conditioned overnight at a low humidity condition of 10 ° C. and 15% RH, and then passed through a jig for continuously changing a radius of curvature. The position where the crack occurred was represented by the distance from the reference line. The smaller the value, the smaller the number of cracks.

[Curling Test] A thermosensitive recording material (sample) cut into a 10 cm square was conditioned at 25 ° C. and 20% RH for 4 hours, then placed on a horizontal plate, and the distance from both sides of the plate to the plate (Mm). The smaller this value is, the smaller the curling is. Table 1 shows the above results.

[0111]

[Table 1]

[0112]

As described above, according to the recording material of the present invention, it is possible to prevent cracking during storage under low humidity conditions while preventing curling.

Claims (4)

[Claims] 1. A recording material having at least an image recording layer and a protective layer on a support, wherein the total coating dry thickness on the image recording layer side is 15 μm or more, and the protective layer contains a swellable inorganic layered compound. Recording material characterized by the following. 2. A recording material having at least an image recording layer and a protective layer on a support, and a second protective layer between the image recording layer and the protective layer, wherein the total coating dry thickness on the image recording layer side is A recording material having a thickness of 15 μm or more, wherein the second protective layer contains a swellable inorganic layered compound. 3. The thermosensitive recording layer (A), wherein the image recording layer contains an electron donating colorless dye and an electron accepting compound, a diazonium salt compound having a maximum absorption wavelength of 360 ± 20 nm, and a diazonium salt compound. A heat-sensitive recording layer (B) containing a coupler which reacts to color when heated and has a maximum absorption wavelength of 4
A diazonium salt compound having a diameter of 00 ± 20 nm, and a thermosensitive recording layer (C) containing a coupler which reacts with the diazonium salt compound when heated to form a color, wherein the second protective layer is provided on the thermosensitive recording layer. Light transmittance adjusting layer,
The recording material according to claim 2, wherein the light transmittance adjusting layer contains a swellable inorganic layered compound. 4. The image recording layer according to claim 1, wherein the maximum absorption wavelength is 34.
A heat-sensitive recording layer (D) containing a diazonium salt compound having a wavelength of 0 ± 20 nm, a coupler which reacts with the diazonium salt compound when heated to form a color, and a maximum absorption wavelength of 360 ± 20 n
m, a thermosensitive recording layer (E) containing a coupler which reacts with the diazonium salt compound when heated to give a color, and a diazonium salt compound having a maximum absorption wavelength of 400 ± 20 nm and the diazonium salt compound. A heat-sensitive recording layer (F) containing a coupler that reacts with heat to form a color, wherein the second protective layer is a light transmittance adjusting layer provided on the image recording layer; 3. The swellable inorganic layered compound is contained in the adjustment layer.
Recording material described in 1.