JPH10297109A - Thermal recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the keeping stability and dynamic sensitivity of a colored image by providing n intermediate layer between a support and a heat-sensitive coloring layer to specify the thermal conductivity between the support and the intermediate layer and at the same time, adding at least, one type of diphenylsulfone crosslinking compound selected from among the chemical compounds of this category expressed by a specific formula to the heat-sensitive coloring layer. SOLUTION: The thermal conductivity between a support and an intermediate layer is set below 0.7 kcal/mh deg.C. In addition, a heat-sensitive coloring layer contains at least, one type of diphenylsulfone crosslinked compound which is selected from among the chemical compounds of this category and is expressed by formula I [in the formula, X, Y are 1-12C saturated and unsaturated hydrocarbon groups and 1-12C hydrocarbon group with an ether bond or by formula II (in the formula, R is a methylene group or an ethylene group; and T is a hydrogen atom and 1-4C alkyl groups). R1 -R6 are a halogn atom, 1-6C alkyl groups and alkenyl groups; m, n, p, q, r, t are at integer of 0-4 and when the integer is 2 or more, R1 -R6 may be different respectively; and a is an integer of 0-10]. Thus it is possible to enhance the keeping stability and dynamic sensitivity of a colored image.

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 recording material having excellent storage stability of a color image and high color sensitivity.

[0002]

2. Description of the Related Art A recording material utilizing color development by a reaction between a color-forming dye and a developer can be recorded in a relatively simple apparatus in a short time without performing complicated processing such as development and fixing. It is widely used for thermal recording paper for output recording of a printer or the like, or pressure-sensitive copying paper for a form for simultaneously copying several sheets. As these recording materials, those which rapidly develop color, maintain the whiteness of uncolored portions (hereinafter referred to as "background"), and have high color fastness of developed images and background are demanded. Furthermore, in recent years, it has been used in a large amount in fields where the reliability of recorded images such as labels is emphasized, and is used for plasticizers and fats and oils contained in organic polymer materials used for packaging and the like. There is a need for recording materials that exhibit high storage stability. For this purpose, various auxiliaries such as a color-forming dye, a developer and a storage stabilizer have been developed, but none of them have been found to be sufficiently satisfactory.

Similar to the compounds of the present invention include:
Compounds having a skeleton of a diphenyl sulfone cross-linked compound are disclosed in JP-B-5-194368 and JP-B-5-310.
683 and the like. Further, Japanese Unexamined Patent Publication No.
No. 13, International Publications WO93 / 06074, WO95 / 3
There is 3714. These compounds are still not sufficiently satisfactory in terms of high preservation of images. In addition, recording materials with improved storage stability of these images generally have poor color-forming sensitivity, failing to obtain sufficient color-forming density and dynamic sensitivity.

[0004]

[0005] In recording materials, improvements in storage stability of color images, especially in recent years, such as plasticizer resistance, oil resistance, light resistance, and moist heat resistance have been awaited. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, to provide a color image having excellent storage stability, high dynamic sensitivity, sufficient color density, and excellent dot reproducibility and heat matching. To provide a recording material.

[0005]

According to the present invention, there is provided a heat-sensitive recording material having a heat-sensitive color-forming layer on a support, which is provided with a heat-sensitive color-forming layer. The intermediate layer is provided between the support and the heat-sensitive color-forming layer. The thermal conductivity of the layer is set to 0.70 Kcal / mh ° C. or less, and the heat-sensitive color-forming layer has the general formula (I)

[0006]

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[Wherein, X and Y may be different from each other and may have a linear or branched C 1 -C 12 saturated;
A hydrocarbon group which may have an unsaturated or ether bond, or

[0008]

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(R represents a methylene group or an ethylene group, T represents a hydrogen atom or a C ₁ -C ₄ alkyl group). R _{1 to} R ₆ are each independently a halogen atom, C ₁
To C ₆ alkyl and alkenyl groups. Also, m,
n, p, q, r, and t represent an integer from 0 to 4, and when 2 or more, R _{1 to} R ₆ may be different from each other.
a represents an integer of 0 to 10. ] It is a heat-sensitive recording material characterized by containing at least one of diphenylsulfone cross-linkable compounds represented by the following formulas:

In the present invention, the main component of the intermediate layer is plastic hollow particles, the hollow ratio of the plastic spherical hollow particles is 50% or more, and the average particle diameter of the plastic spherical hollow particles is 2 to 10 μm. 90% hollow rate
A heat-sensitive recording material characterized by the above.
Further, the present invention provides that the main component of the intermediate layer is an expandable plastic filler, and that the intermediate layer having an expandable plastic filler as a main component is subjected to a surface treatment so that the surface smoothness is 100%.
Provided is a heat-sensitive recording material characterized by being set to 0 second or longer. Further, the present invention is a heat-sensitive recording material, wherein the main component of the intermediate layer is an inorganic pigment, the oil absorption of the inorganic pigment is 50 ml / 100 g or more, and the inorganic pigment is calcined kaolin. Provided is a thermosensitive recording material characterized by the following features.

The following are specific examples of the groups represented by X and Y. Methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, methylmethylene group, dimethylmethylene Group, methylethylene group, methyleneethylene group, ethylethylene group, 1,2-dimethylethylene group, 1-methyltrimethylene group, 1-methyltetramethylene group, 1,3-dimethyltrimethylene group, 1-ethyl-4 -Methyl-tetramethylene group, vinylene group, propenylene group, 2-butenylene group, ethynylene group, 2-butynylene group, 1-vinylethylene group, ethyleneoxyethylene group, tetramethyleneoxytetramethylene group, ethyleneoxyethyleneoxyethylene group , Ethylene oxide Methyleneoxy ethylene, 1,3-dioxane -5,
5-bismethylene group, 1,2-xylyl group, 1,3-xylyl group, 1,4-xylyl group, 2-hydroxytrimethylene group, 2-hydroxy-2-methyltrimethylene group, 2-hydroxy-2-ethyl Examples include a trimethylene group, a 2-hydroxy-2-propyl trimethylene group, a 2-hydroxy-2-isopropyl trimethylene group, and a 2-hydroxy-2-butyl trimethylene group. R ₁ ~
The alkyl group or alkenyl group for R ₆ is a C ₁ -C ₆ alkyl group or a C ₂ -C ₄ alkenyl group, and specific examples include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. , N-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, n-hexyl group, isohexyl group, 1-methylpentyl group, 2
-Methylpentyl group, vinyl group, allyl group, isopropenyl group, 1-propenyl group, 2-butenyl group, 3-butenyl group, 1,3-butanedienyl group, 2-methyl-2-
And a propenyl group. The halogen atom represents chlorine, bromine, fluorine, and iodine.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the heat-sensitive recording material of the present invention, the heat-sensitive coloring layer needs to contain at least one diphenylsulfone cross-linkable compound represented by the general formula (I). When a in the formula is 0, it is necessary to further contain one or more crosslinked compounds.

Particularly preferred compounds are those represented by the general formula (II), which contain two or more compounds which differ only in the value of a.

[0014]

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Among the compounds represented by the general formula (I) used in the present invention, the compound wherein a = 0 is disclosed in JP-A-7-149713.
No., International Publications WO93 / 06074, WO95 / 337
No. 14, typically 1,3-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] -2-hydroxypropane 1,1-bis [4- (4-hydroxyphenylsulfonyl) ) Phenoxy] methane 1,2-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] ethane 1,3-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] propane 1,4-bis [4- (4 -Hydroxyphenylsulfonyl) phenoxy] butane 1,5-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] pentane 1,6-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] hexane α, α'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] -p-xylene α, α'-bi [4- (4-hydroxyphenylsulfonyl) phenoxy] -m-xylene α, α'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] -o-xylene 2,2'-bis [4- (4- (Hydroxyphenylsulfonyl) phenoxy] diethyl ether 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] dibutyl ether 1,2-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] ethylene 1,4- Bis [4- (4-hydroxyphenylsulfonyl) phenoxy] -2-butene;

Among the compounds represented by the general formula (I) of the present invention, the compounds in which a = 1 or more can be specifically exemplified below. (1-1) 4,4'-bis [4- [4- (4-hydroxyphenylsulfonyl) phenoxy] -2-trans-
Butenyloxy] diphenylsulfone Melting point (° C) 176-180 (1-2) 4,4′-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-4-butyloxy] diphenylsulfone Melting point (° C) 215-220 (1- 3) 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-3-propyloxy] diphenylsulfone Melting point (° C) 237-242 (1-4) 4,4'-bis [4- (4 -Hydroxyphenylsulfonyl) phenoxy-2-ethyloxy] diphenylsulfone (1-5) 4- [4- (4-hydroxyphenylsulfonyl) phenoxy-4-butyloxy] -4 '-[4-
(4-hydroxyphenylsulfonyl) phenoxy-
3-propyloxy] diphenylsulfone (1-6) 4- [4- (4-hydroxyphenylsulfonyl) phenoxy-4-butyloxy] -4 '-[4-
(4-hydroxyphenylsulfonyl) phenoxy-
2-ethyloxy] diphenylsulfone (1-7) 4- [4- (4-hydroxyphenylsulfonyl) phenoxy-3-propyloxy] -4 '-[4
-(4-hydroxyphenylsulfonyl) phenoxy-2-ethyloxy] diphenylsulfone (1-8) 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-5-pentyloxy] diphenylsulfone (1-9 ) 4,4'-Bis [4- (4-hydroxyphenylsulfonyl) phenoxy-6-hexyloxy] diphenylsulfone Melting point (° C) 133-136 (1-10) 4- [4- [4- (4-hydroxy Phenylsulfonyl) phenoxy] -2-trans-butenyloxy] -4 '-[4- (4-hydroxyphenylsulfonyl) phenoxy-4-butyloxy] diphenylsulfone (1-11) 4- [4- (4-hydroxyphenylsulfonyl) ) Phenoxy-2-trans-butenyloxy]
-4 '-[4- (4-hydroxyphenylsulfonyl)
Phenoxy-3-propyloxy] diphenylsulfone (1-12) 4- [4- [4- (4-hydroxyphenylsulfonyl) phenoxy] -2-trans-butenyloxy] -4 '-[4-
(4-hydroxyphenylsulfonyl) phenoxy-2
-Ethyloxy] diphenyl sulfone (1-13) 1,4-bis [4- [4- [4- (4-hydroxyphenylsulfonyl) phenoxy-2-trans-butenyloxy] phenylsulfonyl] phenoxy] -cis-2-butene Melting point (C) 185-190 (1-14) 1,4-bis [4- [4- [4- (4-hydroxyphenylsulfonyl) phenoxy-2-trans-butenyloxy] phenylsulfonyl] phenoxy] -trans-2 -Butene melting point (° C) 240-243 (1-15) 4,4'-bis [4- [4- (2-hydroxyphenylsulfonyl) phenoxy] butyloxy]
Diphenyl sulfone (1-16) 4,4'-bis [4- [2- (4-hydroxyphenylsulfonyl) phenoxy] butyloxy]
Diphenyl sulfone (1-17) 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-2-ethyleneoxyethoxy] diphenyl sulfone Melting point (° C) 130-134 (1-18) 4,4'- Bis [4- (4-hydroxyphenylsulfonyl) phenyl-1,4-phenylenebismethyleneoxy] diphenylsulfone Melting point (C) 148-152 (1-19) 4,4'-bis [4- (4-hydroxyphenyl) (Sulfonyl) phenyl-1,3-phenylenebismethyleneoxy] diphenylsulfone (1-20) 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenyl-1,2-phenylenebismethyleneoxy] diphenylsulfone (° C) 224 to 227 (1-21) 2,2'-bis [4- [4- [4 (4
(Hydroxyphenylsulfonyl) phenoxy-2-ethyleneoxyethoxy] phenylsulfonyl] phenoxy] diethyl ether (1-22) α, α'-bis [4- [4- [4- (4-
(Hydroxyphenylsulfonyl) phenyl-1,4-phenylenebismethyleneoxy] phenylsulfonyl] phenoxy] -p-xylene (1-23) α, α'-bis [4- [4- [4- (4-
(Hydroxyphenylsulfonyl) phenyl-1,3-phenylenebismethyleneoxy] phenylsulfonyl] phenoxy] -m-xylene (1-24) α, α'-bis [4- [4- [4- (4-
(Hydroxyphenylsulfonyl) phenyl-1,2-phenylenebismethyleneoxy] phenylsulfonyl] phenoxy] -o-xylene (1-25) 2,4′-bis [2- (4-hydroxyphenylsulfonyl) phenoxy-2-ethylene Oxyethoxy] diphenylsulfone (1-26) 2,4'-bis [4- (2-hydroxyphenylsulfonyl) phenoxy-2-ethyleneoxyethoxy] diphenylsulfone (1-27) 4,4'-bis [3 5-dimethyl-4
-(3,5-Dimethyl-4-hydroxyphenylsulfonyl) phenoxy-2-ethyleneoxyethoxy] diphenylsulfone (1-28) 4,4'-bis [3-allyl-4- (3-
Allyl-4-hydroxyphenylsulfonyl) phenoxy-2-ethyleneoxyethoxy] diphenylsulfone (1-29) 4,4'-bis [3,5-dimethyl-4-
(3,5-dimethyl-4-hydroxyphenylsulfonyl) phenyl-1,4-phenylenebismethyleneoxy] diphenylsulfone (1-30) 4,4'-bis [3,5-dimethyl-4-
(3,5-dimethyl-4-hydroxyphenylsulfonyl) phenyl-1,3-phenylenebismethyleneoxy] diphenylsulfone (1-31) 4,4'-bis [3,5-dimethyl-4-
(3,5-dimethyl-4-hydroxyphenylsulfonyl) phenyl-1,2-phenylenebismethyleneoxy] diphenylsulfone (1-32) 4,4'-bis [3-allyl-4- (3-
Allyl-4-hydroxyphenylsulfonyl) 1,4-
Phenylenebismethyleneoxy] diphenylsulfone (1-33) 4,4'-bis [3-allyl-4- (3-
Allyl-4-hydroxyphenylsulfonyl) 1,3-
Phenylenebismethyleneoxy] diphenylsulfone (1-34) 4,4'-bis [3-allyl-4- (3-
Allyl-4-hydroxyphenylsulfonyl) 1,2-
Phenylenebismethyleneoxy] diphenylsulfone (1-35) 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-2-hydroxypropyloxy] diphenylsulfone (1-36) 1,3-bis [4 -[4- [4- (4-hydroxyphenylsulfonyl) phenoxy-2-hydroxypropyloxy] phenylsulfonyl] phenoxy] -2-hydroxypropane

Representative examples of compositions containing two or more compounds of the general formula (I) are shown below.

(2-1) 2,2'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] diethyl ether and 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-2-ethylene Combination of [oxyethoxy] diphenyl sulfone (2-2) α, α'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] -p-xylene and 4,
Combination of 4'-bis [4- (4-hydroxyphenylsulfonyl) phenyl-1,4-phenylenebismethyleneoxy] diphenylsulfone (2-3) α, α'-bis [4- (4-hydroxyphenylsulfonyl) [Phenoxy] -m-xylene and 4,
Combination of 4'-bis [4- (4-hydroxyphenylsulfonyl) phenyl-1,3-phenylenebismethyleneoxy] diphenylsulfone (2-4) α, α'-bis [4- (4-hydroxyphenylsulfonyl) [Phenoxy] -o-xylene and 4,
Combination of 4'-bis [4- (4-hydroxyphenylsulfonyl) phenyl-1,2-phenylenebismethyleneoxy] diphenylsulfone (2-5) 2,2'-bis [4- (4-hydroxyphenylsulfonyl) Phenoxy] diethyl ether and 4,
4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-2-ethyleneoxyethoxy] diphenylsulfone and 2,2'-bis [4- [4- [4-
(4-hydroxyphenylsulfonyl) phenoxy-2
Combination of -ethyleneoxyethoxy] phenylsulfonyl] phenoxy] diethyl ether (2-6) α, α'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] -p-xylene and 4,
4'-bis [4- (4-hydroxyphenylsulfonyl) phenyl-1,4-phenylenebismethyleneoxy] diphenylsulfone and α, α'-bis [4- [4
Combination of-[4- (4-hydroxyphenylsulfonyl) phenyl-1,4-phenylenebismethyleneoxy] phenylsulfonyl] phenoxy] -p-xylene (2-7) α, α'-bis [4- (4- Hydroxyphenylsulfonyl) phenoxy] -m-xylene and 4,
4'-bis [4- (4-hydroxyphenylsulfonyl) phenyl-1,3-phenylenebismethyleneoxy] diphenylsulfone and α, α'-bis [4- [4
Combination of-[4- (4-hydroxyphenylsulfonyl) phenyl-1,3-phenylenebismethyleneoxy] phenylsulfonyl] phenoxy] -m-xylene (2-8) α, α'-bis [4- (4- Hydroxyphenylsulfonyl) phenoxy] -o-xylene and 4,
4'-bis [4- (4-hydroxyphenylsulfonyl) phenyl-1,2-phenylenebismethyleneoxy] diphenylsulfone and α, α'-bis [4- [4
Combination of-[4- (4-hydroxyphenylsulfonyl) phenyl-1,2-phenylenebismethyleneoxy] phenylsulfonyl] phenoxy] -o-xylene (2-9) 1,4-bis [4- (4-hydroxy Combination of phenylsulfonyl) phenoxy] -trans-2-butene and 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-2-trans-butenyloxy] diphenylsulfone (2-10) 1,2-bis Combination of [4- (4-hydroxyphenylsulfonyl) phenoxy] -ethane and 4,4'-bis [2- (4-hydroxyphenylsulfonyl) phenoxy-ethyloxy] diphenylsulfone (2-11) 1,4-bis [ 4- (4-hydroxyphenylsulfonyl) phenoxy] butane and Combination of 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-butyloxy] diphenylsulfone (2-12) 1,6-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] hexane and 4,4 Combination of '-bis [6- (4-hydroxyphenylsulfonyl) phenoxy-hexyloxy] diphenylsulfone (2-13) 1,3-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] -2-hydroxypropane Combination with 4,4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-2-hydroxypropyloxy] diphenylsulfone (2-14) 1,3-bis [4- (4-hydroxyphenylsulfonyl) phenoxy 2-hydroxypropane and 4,4'-bis [ - (4-hydroxyphenyl sulfonyl) phenoxy-2-hydroxypropyl oxy] diphenyl sulfone and 1,3-bis [4- [4
Combination with-[4- (4-hydroxyphenylsulfonyl) phenoxy-2-hydroxypropyloxy] phenylsulfonyl] phenoxy] -2-hydroxypropane

In addition, in the general formula (II), a = 0 to 0
A composition containing 10 in an arbitrary ratio can be preferably used.

In the present invention, the heat-sensitive color-forming layer has the general formula (I)
Wherein an intermediate layer is provided between the support and the thermosensitive coloring layer, and the thermal conductivity of the support and the intermediate layer is set to 0.7 Kc.
al / mh ° C. or lower, the storage stability of the image,
Particularly, it is excellent in plasticizer resistance and has improved coloring sensitivity.

The thermal conductivity of the intermediate layer is 0.7 Kcal / mh
When the temperature is lower than 0 ° C., the intermediate layer acts as a heat insulating layer, and the heat energy of the thermal head or the like can be effectively used in the heat-sensitive recording layer, and a heat-sensitive recording material having high color sensitivity can be obtained.

The thermal conductivity of the intermediate layer is 0.7 Kcal / mh
In order to make the temperature below ℃, it is preferable to contain fine hollow particles as a main component of the intermediate layer. As the hollow particles, various kinds of conventionally known hollow particles can be used, for example, glass, ceramics, plastics and the like. Although there is a hollow body formed of the various materials described above, it is particularly preferable to contain plastic hollow particles. The plastic hollow particles are made of a thermoplastic resin as a shell. As the resin, in particular, acrylic resin such as acrylate ester, acrylonitrile, styrene resin such as styrene or a copolymer thereof, and vinylidene chloride A copolymer resin mainly composed of acrylonitrile is preferred. The hollow particles contained in the intermediate layer preferably have a hollow ratio of 20% or more, and the higher the hollow ratio, the more preferable, and the better is 50% or more. Especially 90%
Those described above are preferred. Here, the hollow ratio is: hollow ratio = (inner diameter of hollow particles / outer diameter of hollow particles) × 100
(%).

The particle size of the hollow particles is usually 20 μm or less, and the finer the particles, the more desirable. As a result, the surface of the intermediate layer becomes smooth, the surface smoothness after the application of the thermosensitive coloring layer and after the calendering treatment is improved, and the dot reproducibility is improved. In particular, those having an average particle diameter of 2 to 10 μm are preferable.

As the main component of the intermediate layer, a foamable plastic filler can also be used. The expandable plastic filler is a minute hollow particle which has a thermoplastic resin as a shell, contains air or other gas therein, and becomes a foamed state after heating. The thermoplastic resin that forms the shell includes polystyrene, polyvinyl chloride, polyvinylidene chloride,
Examples thereof include polyvinyl acetate, polyacrylate, polyacrylonitrile, polybutadiene, and a copolymer thereof, and a copolymer resin mainly containing vinylidene chloride and acrylonitrile is preferable. In addition, propane or butane is generally used as a foaming agent contained in the shell.

Since the surface of the intermediate layer formed on the support has considerable irregularities, it is preferable to smooth the plane by calendering after forming the intermediate layer. In this case, the smoothness of the surface is preferably 1000 seconds or more.

Further, as a main component of the intermediate layer, an inorganic pigment can be preferably used. As a result, the improvement of the adhesion of the waste to the thermal head and the improvement of the recording sensitivity are achieved.
As inorganic pigments, calcined kaolin, aluminum oxide,
Magnesium carbonate, diatomaceous earth, aluminum silicate,
Aluminum silicate, magnesium silicate, calcium silicate, sodium aluminosilicate, magnesium aluminosilicate, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate,
Examples include clay, talc, surface-treated calcium and silica, and the like. In particular, calcined kaolin and amorphous silica have excellent heat insulating properties and have the effect of further improving the recording sensitivity, so that they can be preferably used. Further, fogging at the interface of the coloring layer can be prevented, and the whiteness can be increased.

In order to further improve the oil absorbing property of the intermediate layer and reduce the amount of residue in the thermal head, the oil absorption of the inorganic pigment is reduced to 5%.
It is preferably 0 ml / 100 g or more. Specifically, diatomaceous earth, fired diatomaceous earth, flux fired diatomaceous earth,
Particulate anhydrous aluminum oxide, particulate titanium oxide, magnesium carbonate, white carbon, particulate anhydrous silica,
And magnesium aminosilicate.

In order to provide an intermediate layer on a support, the above-mentioned fine hollow particles and the like are dispersed in water together with a binder such as a known water-soluble polymer or aqueous polymer emulsion, and this is applied to the surface of the support. Obtained by drying. In this case, the coating amount of the fine hollow particles is at least 1 g per 1 m ² of the support, and the coating amount of the binder resin may be an amount that bonds the intermediate layer to the support.

It is also possible to form an intermediate layer containing fine hollow particles and a pigment. In this case, the fine hollow particles and the pigment are dispersed in water together with a binder, applied to the surface of the support, and dried. Obtained by:

Examples of commonly known water-soluble polymers and aqueous emulsions suitably used as a binder include, for example,
Polyvinyl alcohol, starch and derivatives thereof, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, cellulose derivatives such as ethylcellulose, sodium polyacrylate,
Polyvinyl pyrrolidone, acrylamide / acrylate copolymer, acrylamide / acrylate / methacrylic acid terpolymer, styrene / maleic anhydride alkali salt, isobutylene / maleic anhydride copolymer alkali In addition to water-soluble polymers such as salt, polyacrylamide, sodium alginate, gelatin, casein, polyvinyl acetate, polyurethane, styrene / butadiene copolymer, polybutyl methacrylate, ethylene /
Latexes such as vinyl acetate copolymers and styrene / butadiene / acrylic copolymers can be used.

In order to obtain the heat-sensitive recording material of the present invention, after forming an intermediate layer by binding and supporting a hollow filler or the like on a support, the intermediate layer contains a leuco dye, a developer and an auxiliary component. What is necessary is just to provide a thermosensitive coloring layer.

When the compound of the present invention is used for heat-sensitive recording paper, it may be carried out in the same manner as in the use of known image storage stabilizers and color developers. For example, fine particles of the compound of the present invention and a color-forming dye Can be produced by mixing a suspension in which each of the fine particles is dispersed in an aqueous solution of a water-soluble binder such as polyvinyl alcohol or cellulose, applying the suspension to a support such as paper, and drying.

When used as an image storage stabilizer, the compound of the present invention is used in an amount of 0.1 to 5 parts by weight, preferably 0.2 to 5 parts by weight, per 1 part by weight of the chromogenic dye. 2 parts by weight, and when used as a color developer, the amount is 1 to 10 parts by weight, preferably 1.5 to 5 parts by weight, per 1 part by weight of the color-forming dye.

The above dispersion further contains other developers, other image stabilizers, sensitizers, fillers, dispersants, antioxidants, desensitizers, antiblocking agents, defoamers, light stabilizers. , A fluorescent whitening agent and the like can be contained as necessary.

These agents may be contained in the color-forming layer. However, in the case of a multilayer structure, they may be contained in any layer such as a protective layer. In particular, when an overcoat layer or an undercoat layer is provided above and / or below the color-forming layer, these layers can contain an antioxidant, a light stabilizer, and the like. In addition, antioxidants,
The light stabilizer can be contained in these layers in the form of being encapsulated in microcapsules as required.

Examples of the color-forming dye used in the recording material of the present invention include leuco dyes such as fluoran dyes, phthalide dyes, lactam dyes, triphenylmethane dyes, phenothiazine dyes and spiropyran dyes. It is not limited, and any color-forming dye that can be colored by contact with a color developer, which is an acidic substance, can be used.
These color-forming dyes are used alone, and a recording material of the color to be formed is of course manufactured, but two or more of them can be mixed and used. For example, red,
A recording material that develops a true black color can be produced by using a mixture of three primary color developing dyes of blue and green or a black coloring dye.

Among these dyes, fluoran-based dyes are exemplified by 3-diethylamino-6-methyl-7-.
Anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3- (N-ethyl-N-isobutylamino) -6-methyl-7-anilinofluoran, 3- (N- Methyl-N-propylamino) -6-methyl-7-anilinofluoran, 3- (N-ethyl-N
-Isopentylamino) -6-methyl-7-anilinofluoran, 3-diethylamino-7- (o-chloroanilino) fluoran, 3-dibutylamino-7- (o-chloroanilino) fluoran, 3- (N-ethyl -P-toluidino) -6-methyl-7-anilinofluoran, 3
-(N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluoran, 3-pyrrolidino-6
Methyl-7-anilinofluoran, 3-piperidino-6
-Methyl-7-anilinofluoran, 3-dimethylamino-7- (m-trifluoromethylanilino) fluoran, 3-dipentylamino-6-methyl-7-anilinofluoran, 3- (N-ethoxy Propyl-N-ethylamino) -6-methyl-7-anilinofluoran, 3-
Dibutylamino-7- (o-fluoroanilino) fluoran, 3-diethylaminobenzo [a] fluoran, 3-
Dimethylamino-6-methyl-7-chlorofluoran,
3-diethylamino-5-methyl-7-dibenzylaminofluoran, 3-diethylamino-7-dibenzylaminofluoran, 3-diethylamino-5-chlorofluoran, 3-diethylamino-6- (N, N'- Dibenzylamino) fluoran, 3,6-dimethoxyfluoran 2,4-dimethyl-6- (4-dimethylaminophenyl) aminofluoran and the like. Further, as the near infrared absorbing dye, 3- (4- (4- (4-anilino)-
Anilino) anilino-6-methyl-7-chlorofluoran, 3,3-bis (2- (4-dimethylaminophenyl) -2- (4-methoxyphenyl) vinyl) -4,
5,6,7-tetrachlorophthalide, 3,6,6′-tris (dimethylamino) spiro [fluorene-9,3 ′
-Phthalide] and the like. Other examples include 3,3-bis (4'-diethylaminophenyl) -6-diethylaminophthalide.

In the recording material of the present invention, other color developing agents can be further added. Representative examples thereof include bisphenol A, 4,4'-sec-butylidene bisphenol, and 4,4'- Cyclohexylidene bisphenol,
2,2-dimethyl-3,3-bis (4-hydroxyphenyl) butane, 2,2′-dihydroxydiphenyl, pentamethylene-bis (4-hydroxybenzoate),
2,2-dimethyl-3,3-di (4-hydroxyphenyl) pentane, 2,2-di (4-hydroxyphenyl)
Bisphenol compounds such as hexane, 4,4′-dihydroxydiphenylthioether, 1,7-di (4-hydroxyphenylthio) -3,5-dioxaheptane,
Sulfur-containing bisphenol compounds such as 2,2'-bis (4-hydroxyphenylthio) diethyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenylthioether, benzyl 4-hydroxybenzoate, 4-hydroxybenzoic acid Ethyl, propyl 4-hydroxybenzoate, isopropyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate, isobutyl 4-hydroxybenzoate, chlorobenzyl 4-hydroxybenzoate, methylbenzyl 4-hydroxybenzoate, 4-hydroxybenzoate 4-hydroxybenzoic acid esters such as diphenylmethyl acid, metal benzoates such as zinc benzoate and zinc 4-nitrobenzoate, salicylic acids such as 4- (2- (4-methoxyphenyloxy) ethyloxy) salicylic acid, Zinc salicylate, bis @ 4- Salicylic acid metal salts such as octyloxy carbonylamino) -2-hydroxy-benzoic acid} zinc, 4,4'-dihydroxydiphenyl sulfone, 2,4'-dihydroxydiphenyl sulfone, 4-
Hydroxy-4′-methyldiphenylsulfone, 4-hydroxy-4′-isopropoxydiphenylsulfone,
4-hydroxy-4′-butoxydiphenyl sulfone,
4,4'-dihydroxy-3,3'-diallyldiphenylsulfone, 3,4-dihydroxy-4'-methyldiphenylsulfone, 4,4'-dihydroxy-3,3 ',
Hydroxysulfones such as 5,5'-tetrabromodiphenylsulfone; dimethyl 4-hydroxyphthalate;
4-hydroxyphthalic acid diesters such as dicyclohexyl-hydroxyphthalate and diphenyl 4-hydroxyphthalate; esters of hydroxynaphthoic acid such as 2-hydroxy-6-carboxynaphthalene; hydroxyacetophenone; p-phenylphenol; 4-hydroxy Benzyl phenylacetate, p-benzylphenol, hydroquinone-monobenzyl ether, trihalomethyl sulfones such as tribromomethylphenyl sulfone, sulfonylureas such as 4,4'-bis (p-toluenesulfonylaminocarbonylamino) diphenylmethane, tetra Examples thereof include cyanoquinodimethanes and 2,4-dihydroxy-2'-methoxybenzanilide.

Typical examples of image storage stabilizers that can be added include 4-benzyloxy-4'-.
Epoxy group-containing diphenylsulfones such as (2-methylglycidyloxy) -diphenylsulfone and 4,4′-diglycidyloxydiphenylsulfone;
4-diglycidyloxybenzene, 4- (α- (hydroxymethyl) benzyloxy) -4′-hydroxydiphenylsulfone, 2-propanol derivative, salicylic acid derivative, metal salt of oxynaphthoic acid derivative (particularly zinc salt), 2, Examples thereof include metal salts of 2-methylenebis (4,6-tert-butylphenyl) phosphate and other water-insoluble zinc compounds.

Examples of the sensitizer include higher fatty acid amides such as stearamide, benzamide, stearic anilide, acetoacetic anilide, thioacetanilide, dibenzyl oxalate, di (4-methylbenzyl) oxalate, and oxalic acid. Di (4-chlorobenzyl), dimethyl phthalate, dimethyl terephthalate, dibenzyl terephthalate, dibenzyl isophthalate, bis (tert-butylphenol) s, diphenylsulfone and derivatives thereof, diethers of 4,4′-dihydroxydiphenylsulfone, Diethers of 2,4′-dihydroxydiphenyl sulfone, 1,2-bis (phenoxy) ethane,
1,2-bis (4-methylphenoxy) ethane, 1,2
-Bis (3-methylphenoxy) ethane, 2-naphthol benzyl ether, diphenylamine, carbazole, 2,3-di-m-tolybutane, 4-benzylbiphenyl, 4,4'-dimethylbiphenyl, m-terphenyl, di- β-naphthylphenylenediamine, phenyl 1-hydroxy-naphthoate, 2-naphthylbenzyl ether, 4-methylphenyl-biphenyl ether, 2,
2-bis (3,4-dimethylphenyl) ethane, 2,
3,5,6-tetramethyl-4'-methyldiphenylmethane, diphenyl carbonate and the like can be mentioned. Preferably, 1,2-bis (3-methylphenoxy) ethane,
Ethers such as 2-naphthylbenzyl ether, m-terphenyl, 4-benzylbiphenyl, dioxalate (4
-Methylbenzyl), and the like. More preferably, diphenylsulfone and its derivatives, especially diethers of 4,4′-dihydroxydiphenylsulfone and diethers of 2,4′-dihydroxydiphenylsulfone,
4,4'-dimethoxydiphenyl sulfone, 4,4'-
Diethoxydiphenylsulfone, 4,4'-dipropoxydiphenylsulfone, 4,4'-diisopropoxydiphenylsulfone, 4,4'-dibutoxydiphenylsulfone, 4,4'-diisobutoxydiphenylsulfone, 4,4 ' -Dipentyloxydiphenyl sulfone,
4,4′-dihexyloxydiphenyl sulfone, 2,
4'-dimethoxydiphenylsulfone, 2,4'-diethoxydiphenylsulfone, 2,4'-dipropoxydiphenylsulfone, 2,4'-diisopropoxydiphenylsulfone, 2,4'-dibutoxydiphenylsulfone, 2, 4'-diisobutoxydiphenyl sulfone,
2,4'-dipentyloxydiphenyl sulfone, 2,
4'-dihexyloxydiphenyl sulfone and the like can be exemplified.

As the filler, silica, clay, kaolin, calcined kaolin, talc, satin white, aluminum hydroxide, calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, barium sulfate, magnesium silicate,
Aluminum silicate, plastic pigment and the like can be used. Particularly in the recording material of the present invention, an alkaline earth metal salt is preferable. Further, carbonates are preferable, and calcium carbonate, magnesium carbonate and the like are preferable. The filler is used in an amount of 0.1 to 15 parts by weight per 1 part by weight of the coloring dye,
Preferably it is 1 to 10 parts by weight. It is also possible to use a mixture of the above-mentioned other fillers.

Examples of the dispersant include sulfosuccinates such as dioctyl sodium sulfosuccinate, sodium dodecylbenzenesulfonate, sodium lauryl alcohol sulfate and fatty acid salts.

As antioxidants, 2,2'-methylenebis (4-methyl-6-tert-butylphenol),
2′-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-propylmethylenebis (3-methyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert -Butylphenol), 4,4'-thiobis (2-tert-butyl-5-methylphenol), 1,1,3-tris (2-methyl-
4-hydroxy-5-tert-butylphenyl) butane,
1,1,3-tris (2-methyl-4-hydroxy-5
-Cyclohexylphenyl) butane, 4- [4- {1,
1-bis (4-hydroxyphenyl) ethyl} -α, α
-Dimethylbenzyl] phenol and the like.

Examples of the desensitizer include higher aliphatic alcohols, polyethylene glycol, and guanidine derivatives.

Examples of the antiadhesive include stearic acid, zinc stearate, calcium stearate, carnauba wax, paraffin wax, ester wax and the like.

As the light stabilizer, phenyl salicylate, p-tert-butylphenyl salicylate, p-
Salicylic acid-based ultraviolet absorbers such as octylphenyl salicylate, 2,4-dihydroxybenzophenone, 2-
Hydroxy-4-methoxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2′-
Dihydroxy-4-methoxybenzophenone, 2,2 ′
-Dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis (2-methoxy-4-hydroxy-5-
Benzophenone-based ultraviolet absorbers such as benzoylphenyl) methane, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-
5'-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-ter
t-butylphenyl) benzotriazole, 2- (2 ′
-Hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2-
(2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole, 2-
(2'-hydroxy-3 ', 5'-di-tert-amylphenyl) benzotriazole, 2- [2'-hydroxy-3'-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2- (2'-hydroxy-5'-ter
t-octylphenyl) benzotriazole, 2-
[2′-hydroxy-3 ′, 5′-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (2′-hydroxy-3′-dodecyl-5′-
Methylphenyl) benzotriazole, 2- (2′-hydroxy-3′-undecyl-5′-methylphenyl)
Benzotriazole, 2- (2'-hydroxy-3'-
Undecyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tridecyl-5 '
-Methylphenyl) benzotriazole, 2- (2'-
Hydroxy-3′-tetradecyl-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-
3'-pentadecyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3'-hexadecyl-5'-methylphenyl) benzotriazole,
-[2'-hydroxy-4 '-(2 "-ethylhexyl) oxyphenyl] benzotriazole, 2- [2'
-Hydroxy-4 '-(2 "-ethylheptyl) oxyphenyl] benzotriazole, 2- [2'-hydroxy-4'-(2" -ethyloctyl) oxyphenyl]
Benzotriazole, 2- [2'-hydroxy-4'-
(2 "-propyloctyl) oxyphenyl] benzotriazole, 2- [2'-hydroxy-4 '-(2"-
Propylheptyl) oxyphenyl] benzotriazole, 2- [2′-hydroxy-4 ′-(2 ″ -propylhexyl) oxyphenyl] benzotriazole, 2-
[2'-hydroxy-4 '-(1 "-ethylhexyl)
Oxyphenyl] benzotriazole, 2- [2′-hydroxy-4 ′-(1 ″ -ethylheptyl) oxyphenyl] benzotriazole, 2- [2′-hydroxy-
4 '-(1'-ethyloctyl) oxyphenyl] benzotriazole, 2- [2'-hydroxy-4'-
(1 "-propyloctyl) oxyphenyl] benzotriazole, 2- [2'-hydroxy-4 '-(1"-
Propylheptyl) oxyphenyl] benzotriazole, 2- [2′-hydroxy-4 ′-(1 ″ -propylhexyl) oxyphenyl] benzotriazole,
2'-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazole-2-
Yl)] benzotriazole-based ultraviolet absorbers such as condensates of phenol, polyethylene glycol and methyl-3- [3-tert-butyl-5- (2H-benzotriazol-2-yl) -4-hydroxyphenyl] propionate 2,2′-ethylhexyl-2-cyano-3,
3-diphenyl acrylate, ethyl-2-cyano-
Cyanoacrylate-based ultraviolet absorbers such as 3,3-diphenylacrylate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (2,2,6,6-tetramethyl-succinate) Hindered amine ultraviolet absorbers such as 4-piperidyl) ester and 2- (3,5-di-tert-butyl) malonic acid-bis (1,2,2,6,6-pentamethyl-4-piperidyl) ester; , 8-dihydroxy-2-acetyl-3-methyl-6-methoxynaphthalene and related compounds.

Examples of the fluorescent dye include the following. 4,4'-bis [2-anilino-4- (2-hydroxyethyl) amino-1,3,5-triazinyl-6
Amino] stilbene-2,2'-disulfonic acid = disodium salt 4,4'-bis [2-anilino-4-bis (hydroxyethyl) amino-1,3,5-triazinyl-6-amino] stilbene-2 , 2'-Disulfonic acid = disodium salt 4,4'-bis [2-methoxy-4- (2-hydroxyethyl) amino-1,3,5-triazinyl-6-amino] stilbene-2,2'- Disulfonic acid = disodium salt 4,4'-bis [2-methoxy-4- (2-hydroxypropyl) amino-1,3,5-triazinyl-6-amino] stilbene-2,2'-disulfonic acid = 2 Sodium salt 4,4'-bis [2-m-sulfoanilino-4-bis (hydroxyethyl) amino-1,3,5-triazinyl-6-amino] stilbene-2,2'-disulfate Honic acid = disodium salt 4- [2-p-sulfoanilino-4-bis (hydroxyethyl) amino-1,3,5-triazinyl-6-amino] -4 '-[2-m-sulfoanilino-4-bis (Hydroxyethyl) amino-1,3,5-triazinyl-
6-amino] stilbene-2,2'-disulfonic acid = tetrasodium salt 4,4'-bis [2-p-sulfoanilino-4-bis (hydroxyethyl) amino-1,3,5-triazinyl-6-amino ] Stilbene-2,2'-disulphonic acid = tetrasodium salt 4,4'-bis [2- (2,5-disulphoanilino)-
4-phenoxyamino-1,3,5-triazinyl-6
-Amino] stilbene-2,2'-disulfonic acid = hexasodium salt 4,4'-bis [2- (2,5-disulfoanilino)-
4- (p-methoxycarbonylphenoxy) amino-
1,3,5-triazinyl-6-amino] stilbene-
2,2'-disulfonic acid = hexasodium salt 4,4'-bis [2- (p-sulfophenoxy) -4-
Bis (hydroxyethyl) amino-1,3,5-triazinyl-6-amino] stilbene-2,2'-disulfonic acid = tetrasodium salt 4,4'-bis [2- (2,5-disulfoanilino)-
4-formalinylamino-1,3,5-triazinyl-
6-amino] stilbene-2,2'-disulfonic acid = hexasodium salt 4,4'-bis [2- (2,5-disulfoanilino)-
4-bis (hydroxyethyl) amino-1,3,5-triazinyl-6-amino] stilbene-2,2'-disulfonic acid hexasodium salt

[0048]

EXAMPLES Hereinafter, the recording material of the present invention will be described in detail with reference to examples, but is not necessarily limited thereto. The parts and percentages shown below are based on weight.

Example 1 [Liquid A] Plastic non-hollow particles 40 parts (Mitsui Toatsu: SPMM-HS solid content 47%) Styrene / butadiene copolymer latex (47.5%) 13 parts Water 47 parts The above composition The mixture consisting of the following was stirred and dispersed to prepare a liquid A for forming an intermediate layer, and this was mixed with commercially available high-quality paper (basis weight: 52 g /
After drying on the surface of m ² ), the resultant was coated so as to have a weight of 5 g / m ² to obtain an intermediate layer coated paper. [Solution B] 3-Di-n-butylamino-6-methyl-7-anilinofluoran 20 parts Polyvinyl alcohol 10% aqueous solution 20 parts Water 60 parts [Solution C] 4, represented by the general formula (II) 10 parts of a polymer containing 4'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy-2-ethyleneoxyethoxy] diphenylsulfone (a = 0: 36.54%, a = 1: 26.37) %, A = 2: 13.27%, a = 3: 7.09%, a = 4: 3.24%, a = 5: 2.16%, a = 6: 1.75%) Polyvinyl alcohol 10 % Aqueous solution 25 parts Calcium carbonate 15 parts Water 60 parts A mixture comprising the above composition was dispersed using a sand mill so that the average particle size became 2 μm or less.
Liquid] was prepared. Then, [Solution B] and [Solution C] were mixed and stirred at a weight ratio of 1: 6, and then applied and dried on the intermediate layer coated paper so that the dry adhesion amount was 4 to 5 g / m ^2. After calendering, the heat-sensitive recording paper of the present invention was obtained.

Example 2 [D liquid] 50 parts of plastic hollow particles (hollowness: 30%, average particle size: 1.0 μm, solid content: 37.5%) Styrene / butadiene copolymer latex (47.5%) 13 parts Water 37 Part The mixture having the above composition was stirred and dispersed to prepare a liquid D for forming an intermediate layer. Instead of [A solution] in Example 1, [D
Liquid) was used in the same manner as in Example 1 except for using the liquid.

Example 3 [E liquid] 68 parts of plastic hollow particles (hollow ratio: 50%, average particle diameter: 4 μm, solid content: 27.5%) Styrene / butadiene copolymer latex (47.5%) 13 parts Water 19 parts The mixture composed of the components was stirred and dispersed to prepare a liquid E for forming an intermediate layer. [E Solution] in place of [A Solution] in Example 1
Liquid) was used in the same manner as in Example 1 except for using the liquid.

Example 4 [F liquid] Plastic hollow particles 40 parts (hollowness 90%, average particle diameter 4 μm, solid content 23%) Styrene / butadiene copolymer latex (47.5%) 10 parts Water 50 parts From the above composition The resulting mixture was stirred and dispersed to prepare an intermediate layer forming liquid F liquid. [F solution] in place of [A solution] in Example 1
Liquid], the heat-sensitive recording material of the present invention was prepared in the same manner as in Example 1 except that the weight after drying was changed to ² to 3 g / m ² .

Example 5 [Solution G] 15 parts of foamable plastic filler (shell: vinylidene chloride / acrylonitrile copolymer) (blowing agent: isobutane) 10% aqueous solution of polyvinyl alcohol 30 parts water 55 parts A mixture having the above composition was stirred. The mixture was dispersed to prepare an intermediate layer forming liquid G. [G Solution] instead of [A Solution] in Example 1
After drying, the composition is coated and dried so that the weight becomes ² to 3 g / m ² , and then the surface is brought into close contact with the surface of a rotating drum dryer having a heater, and the surface temperature is adjusted to 120 to 130.
Example 1 except that the mixture was foamed by heating for about 2 minutes under the condition of
In the same manner as in Example 1, a thermal recording material was prepared during the present invention.

Example 6 A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 5, except that the surface of the intermediate layer in Example 5 was subjected to a calendering treatment to adjust the surface smoothness to 5000 seconds.

Example 7 [Liquid H] 10 parts of calcium carbonate 10 parts of styrene / butadiene copolymer latex (47.5%) 10 parts of water 80 parts The mixture having the above composition was stirred and dispersed to prepare a liquid H for forming an intermediate layer. It was adjusted. [H Solution] in place of [A Solution] in Example 1
Liquid) was used in the same manner as in Example 1 except for using the liquid.

Example 8 [Solution I] Silica 10 parts Styrene / butadiene copolymer latex (47.5%) 10 parts Water 80 parts The mixture having the above composition was stirred and dispersed to prepare an intermediate layer forming solution I solution. did. [I Solution] in place of [A Solution] in Example 1
Liquid) was used in the same manner as in Example 1 except that the recording material of the present invention was used.

Example 9 [Solution J] 10 parts of calcined kaolin 10 parts of styrene / butadiene copolymer latex (47.5%) 10 parts of water 80 parts The mixture having the above composition was stirred and dispersed to prepare an intermediate layer forming liquid J. It was adjusted. [J Liquid] in Example 1 was replaced with [J
Liquid) was used in the same manner as in Example 1 except for using the liquid.

Comparative Example 1 A heat-sensitive recording material for comparison was obtained in the same manner as in Example 1 except that the intermediate layer of Example 1 was omitted.

Comparative Example 2 The procedure of Example 1 was repeated, except that 4-hydroxy-4'-isopropoxydiphenyl sulfone was used in place of the polymer represented by the general formula (II) in [C solution]. A heat-sensitive recording material for comparison was obtained.

Comparative Example 3 A comparative thermosensitive recording material was obtained in the same manner as in Comparative Example 2 except that the intermediate layer was omitted.

Each of the heat-sensitive recording materials obtained as described above was tested for dynamic color sensitivity and plasticizer resistance. Table 1 shows the results. The test was performed as follows.

(1) Dynamic color development sensitivity Using a thermal printing tester having a thin film head manufactured by Matsushita Electric Parts Co., Ltd., head power 0.45 W / dot, one line recording time 4 msec / l, scanning line density 8 × Printing was performed with a pulse width of 0.2 to 1.2 ms under the condition of 7.7 dots / mm, and the print density was measured with a Macbeth densitometer RD-914, and the density at 0.8 ms was used as dynamic color sensitivity. I let it.

(2) Plasticizer resistance Printing was performed with a heat block of 200 ° C. under the conditions of a pressure of 2 kg / cm ² and 1 second, and three sheets of Shin-Etsu Polymer PVC (polymer wrap 300) were stacked on the printed portion of each printed sample. The print density was measured with a Macbeth densitometer RD-914 after storage for 15 hours in a 40 ° C. environment under a load of 5 kg.

(3) Thermal conductivity Measured using a thermal conductivity meter Q7M-03 manufactured by Kyoto Electronics Industry Co., Ltd.

[0065]

[Table 1]

[0066]

According to the present invention, it is possible to obtain a heat-sensitive recording material having excellent storage stability of a color image, particularly excellent plasticizer resistance, and excellent dynamic color sensitivity. Further, a recording material having high whiteness without sticking can be obtained.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B41M 5/18 101D

Claims (9)

[Claims] In a heat-sensitive recording material having a heat-sensitive color-forming layer on a support, which forms a color when heated, an intermediate layer is provided between the support and the heat-sensitive color-forming layer, and the thermal conductivity of the support and the intermediate layer is set at 0. 70
Kcal / mh ° C. or lower, and the heat-sensitive coloring layer further contains a compound represented by the general formula (I): [Wherein, X and Y may be different from each other and may have a linear or branched hydrocarbon group having 1 to 12 carbon atoms which may be saturated, unsaturated or have an ether bond, or Formula 2 (R represents a methylene group or an ethylene group, T represents a hydrogen atom or a C ₁ -C ₄ alkyl group). R _{1 to} R
₆ each independently represents a halogen atom, a C ₁ -C ₆ alkyl group or an alkenyl group. Also, m, n, p, q, r,
t represents an integer of 0 to 4, is 2 or more when R ₁ to R
₆ may be different from each other. a represents an integer of 0 to 10. ] A thermosensitive recording material comprising at least one of the diphenylsulfone cross-linkable compounds represented by the following formula: 2. The heat-sensitive recording material according to claim 1, wherein the main component of the intermediate layer is plastic hollow particles. 3. The hollow ratio of the spherical hollow particles of plastic is 50.
% Or more. 4. The heat-sensitive recording material according to claim 2, wherein the plastic spherical hollow particles have an average particle diameter of 2 to 10 μm and a hollow ratio of 90% or more. 5. The heat-sensitive recording material according to claim 1, wherein the main component of the intermediate layer is a foamable plastic filler. 6. The heat-sensitive recording material according to claim 5, wherein an intermediate layer containing a foamable plastic filler as a main component is subjected to a surface treatment to have a surface smoothness of 1000 seconds or more. 7. The heat-sensitive recording material according to claim 1, wherein the main component of the intermediate layer is an inorganic pigment. 8. The heat-sensitive recording material according to claim 7, wherein the inorganic pigment has an oil absorption of 50 ml / 100 g or more. 9. The heat-sensitive recording material according to claim 7, wherein the inorganic pigment is calcined kaolin.