JPH07304254A - Thermal recording material - Google Patents

Abstract

PURPOSE:To enhance color forming properties, raw preservabillty and the stability of a developed color image by adding a specific salicylic acid derivative or a metal salt thereof and a metal compd. to the thermal color forming layer containing an electron donating leuco dye and an electron acceptive compd. provided on a support in a solid dispersed state. CONSTITUTION:In a thermal recording material wherein a thermal color forming layer containing an electron donating leuco dye and an electron acceptive compd. is provided on a support, a salicylic acid derivative represented by formula I or a metal salt thereof and a metal compd. are added to the thermal color forming layer. In the formula, R1 is an alkyl group or an aryl group, X is a hydrogen atom, an alkyl group, an aryl group, an alkoxy group or a halogen atom, M is a hydrogen atom or an n-valent metal atom and n is an integer. If necessary, zinc oxide and a fluorane compd. represented by formula II (wherein R2 and R3 are an alkylene group or an aryl group and R4-R6 are a hydrogen atom, a halogen atom or an alkylene group) are added to the thermal color forming layer.

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 color-forming layer containing an electron-donating colorless dye and an electron-accepting compound having improved color-forming property, raw storability and stability of color image. The present invention relates to a heat-sensitive recording material having a support provided on the support.

[0002]

2. Description of the Related Art Recording materials using an electron-donating colorless dye and an electron-accepting compound are pressure-sensitive paper, thermal paper, photosensitive pressure-sensitive paper,
It is already well known as an electrically conductive recording paper and a thermal transfer paper. For example, British Patent No. 2,140,449, US Patent Nos. 4,480,052, and 4,436,920.
Japanese Patent Publication No. 60-23992, JP-A No. 57-1798.
No. 36, No. 60-123556, No. 60-12355.
Details on No. 7 etc. In particular, the thermal recording material is
For details, see No. 4160 and Japanese Patent Publication No. 45-14039. These thermal recording systems are applied to various fields such as facsimiles, printers and labels, and their needs are expanding. However, since the heat-sensitive recording material has a defect that fog is caused by a solvent and the like, and a color developing body is discolored by oils and fats, chemicals, etc., labels, slips, word processor papers, plotters, etc. In the field of paper and the like, the commercial value has been significantly impaired.

The inventors of the present invention have focused their attention on the oil solubility, the solubility in water, the partition coefficient, pKa, the polarity of the substituent and the position of the substituent of each of the electron-donating colorless dye and the electron-accepting compound. , Has pursued the development of good recording materials and recording materials. However, the addition of these resistances has caused a problem that the sensitivity is significantly lowered.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material of high print quality, which has high sensitivity, good raw storability, and good stability of color image.

[0005]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is to provide a thermosensitive recording material having a thermosensitive coloring layer containing an electron-donating colorless dye and an electron-accepting compound on a support. The present invention has been achieved by a heat-sensitive recording material characterized by containing a salicylic acid derivative represented by the general formula (1) or a metal salt thereof and a metal compound.

[0006]

[Chemical 5]

In the general formula (1), R ₁ is an alkyl group or an aryl group, X is a hydrogen atom, an alkyl group, an aryl group, an alkoxy group or a halogen atom, M is a hydrogen atom or an n-valent metal atom, n represents an integer.

In the general formula (1), among the groups represented by R ₁ , an alkyl group having 1 to 20 carbon atoms and an aryl group having 6 to 15 carbon atoms are preferable. The alkyl group may be substituted with an alkoxy group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or a halogen atom. Aryl group has 1 to 1 carbon atoms
It may be substituted with an alkyl group having 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or a halogen atom. As R ₁ , specifically, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group,
Isobutyl group, sec-butyl group, n-amyl group, n-
Hexyl group, n-octyl group, 2-ethylhexyl group,
n-decyl group, n-dodecyl group, n-pentadecyl group,
Preferred are methoxyethyl group, benzyl group, 4-methylbenzyl group, phenyl group, tolyl group and methoxyphenyl group.

In the general formula (1), among the groups represented by X, a hydrogen atom, a chlorine atom, an alkyl group having 1 to 8 carbon atoms,
An aryl group having 6 to 10 carbon atoms and an alkoxy group having 1 to 8 carbon atoms are preferable. The alkyl group, aryl group and alkoxy group may further have a substituent. Specific examples of X include hydrogen atom, chlorine atom, methyl group, ethyl group, isopropyl group, t-butyl group, t-octyl group, benzyl group, α-methylbenzyl group, α, α-dimethylbenzyl group and phenyl. A group and the like are preferable.

In the general formula (1), the divalent or trivalent metal among the metal atoms represented by M is preferable. n is preferably 2 or 3. As M, specifically, metals such as zinc, magnesium, barium, calcium, aluminum, tin, titanium, nickel, cobalt, manganese, and iron are preferable, and zinc, aluminum, magnesium, and calcium are particularly preferable.

The substitution position of the R ₁ OCONH-group is preferably the 4- and 5-positions of salicylic acid.

Specific examples of the salicylic acid derivative according to the present invention are shown below, but the present invention is not limited thereto.

4-methoxycarbonylaminosalicylic acid, 4-ethoxycarbonylaminosalicylic acid, 4-n
-Propyloxycarbonylaminosalicylic acid, 4-isopropyloxycarbonylaminosalicylic acid, 4-n
-Butoxycarbonylaminosalicylic acid, 4-isobutyloxycarbonylaminosalicylic acid, 4-n-hexyloxycarbonylaminosalicylic acid, 4-n-octyloxycarbonylaminosalicylic acid, 4- (2-ethylhexyloxycarbonylamino) salicylic acid, 4-
n-decyloxycarbonylaminosalicylic acid, 4-n
-Dodecyloxycarbonylamino salicylic acid, 4-
(2-methoxyethoxycarbonylamino) salicylic acid, 4-benzyloxycarbonylaminosalicylic acid,
4-phenoxycarbonylaminosalicylic acid, 4-p-
Trilyloxycarbonylaminosalicylic acid, 5-methyl-4-n-octyloxycarbonylaminosalicylic acid, 5-phenyl-4-n-octyloxycarbonylaminosalicylic acid, 5-methoxycarbonylaminosalicylic acid, 5-ethoxycarbonylaminosalicylic acid, 5
-N-propyloxycarbonylamino salicylic acid, 5
-Isopropyloxycarbonylaminosalicylic acid, 5
-N-butoxycarbonylaminosalicylic acid, 5-isobutyloxycarbonylaminosalicylic acid, 5-n-hexyloxycarbonylaminosalicylic acid, 5-n-octyloxycarbonylaminosalicylic acid, 5- (2-
Ethylhexyloxycarbonylamino) salicylic acid,
5-n-decyloxycarbonylamino salicylic acid, 5
-N-dodecyloxycarbonylamino salicylic acid, 5
-(2-methoxyethoxycarbonylamino) salicylic acid, 5-benzyloxycarbonylaminosalicylic acid,
5-phenoxycarbonylaminosalicylic acid, 5-p-
Examples thereof include trilyloxycarbonylaminosalicylic acid, 3-t-butyl-5-n-octyloxycarbonylaminosalicylic acid, 3-n-octyloxycarbonylaminosalicylic acid, and 6-n-octyloxycarbonylaminosalicylic acid. Among these, 4-n-octylcarbonylaminosalicylic acid is particularly preferable.

The salicylic acid derivative represented by the general formula (1) is an oxide, hydroxide, or the like of zinc, aluminum, titanium, silicon, boron, magnesium, or calcium.
When used in combination with one or more of carbonates and carboxylates, the image storability is further improved. Among the metal compounds used in combination, zinc oxide, aluminum hydroxide, calcium carbonate, silicon dioxide and aluminum silicate are particularly preferable, and zinc oxide is particularly preferable.

The dispersed particle size of the salicylic acid derivative represented by the general formula (1) according to the present invention or its metal salt after being atomized in a sand mill or the like is preferably 3 μm in order to obtain color developing sensitivity.
Hereafter, it is preferable to atomize to preferably 2 μm or less. Further, when the salicylic acid derivative of the present invention is used, it is preferable to use a solid dispersion obtained by mixing and dispersing with a metal compound in an aqueous system. Among the metal compounds in this case, zinc oxide, aluminum hydroxide, calcium carbonate, silicon dioxide and aluminum silicate mentioned above are preferable, and zinc oxide is particularly preferable.

In the present invention, salicylic acid derivatives, metal salts of aromatic carboxylic acids, phenol derivatives, phenol resins, novolac resins, metal-treated novolac resins, metal complexes, acid clay, bentonite, which are well known in the present invention, other than the present invention are also known. You may use together electron-accepting compounds, such as. Examples of these are JP-B-40-9309, JP-B-45-14039, JP-A-52-140483,
JP-A-48-51510, JP-A-57-210886
JP-A-58-87089 and JP-A-59-1128.
6, JP-A-60-176795, and JP-A-61-95.
No. 988 and the like.

Some examples of these are 4-tert-butylphenol, 4-phenylphenol, 2,
2'-dihydroxybiphenyl, 2,2-bis (4-
Hydroxyphenyl) propane (bisphenol A),
4,4'-sec-butylidene diphenol, 4,4 '
-Cyclohexylidene diphenol, bis (3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxyphenyl-3 ', 4' dimethylphenyl sulfone, 4-
(4-isopropoxyphenylsulfonyl) phenol, 4,4′-dihydroxydiphenyl sulfide,
1,4-bis- (4'-hydroxycumyl) benzene,
1,3-bis- (4'-hydroxycumyl) benzene,
4,4'-thiobis (6-tert-butyl-3-methylphenol), 4,4'-dihydroxydiphenylsulfone, 4-hydroxybenzoic acid benzyl ester,
3,5-di-tert-butylsalicylic acid, 3-phenyl-5- (α, α-dimethylbenzyl) salicylic acid, 3
-Cumyl-5-t-octylsalicylic acid, 3,5-di-
t-butylsalicylic acid, 3-phenyl-5-t-octylsalicylic acid, 3-methyl-5-α-methylbenzylsalicylic acid, 3-methyl-5-cumylsalicylic acid, 3,5
-Di-t-octylsalicylic acid, 3,5-bis (α-methylbenzyl) salicylic acid, 3-cumyl-5-phenylsalicylic acid, 5-n-octadecylsalicylic acid, 4-pentadecylsalicylic acid, 3,5-bis (α , Α-Dimethylbenzyl) salicylic acid, 3,5-bis-t-octylsalicylic acid, 4-β-dodecyloxyethoxysalicylic acid, 4-methoxy-6-dodecyloxysalicylic acid, 4
-Β-phenoxyethoxysalicylic acid, 4-β-p-ethylphenoxyethoxysalicylic acid, 4- [2 ′-(4
-Methoxyphenyloxy) ethyloxy] salicylic acid, N- (phenoxyacetyl) anthranilic acid and the like, and metal salts thereof. Among these, especially 4- [2'-
It is preferably used in combination with (4-methoxyphenyloxy) ethyloxy] salicylic acid and the metal salt. The above electron-accepting compound is preferably mixed in the salicylic acid derivative of the present invention in a proportion of 10 to 200% by weight. More preferably, it is 10 to 100% by weight. Further, it is more preferable to use two or more of the above-mentioned electron-accepting compounds in combination. In particular, 4- [2 '-(4-methoxyphenyloxy) ethyloxy] salicylic acid (metal salt), 2,2
-Bis (4-hydroxyphenyl) propane, 4- (4
A combination comprising at least one of -isopropoxyphenylsulfonyl) phenol or 1,4-bis- (4'-hydroxycumyl) benzene is preferred. When two or more electron-accepting compounds are used in combination with the salicylic acid derivative represented by the general formula (1), dispersion treatment is performed after mixing the electron-accepting compounds from the viewpoint of high sensitivity. It is preferable.

The electron-accepting compound is preferably used in an amount of 50 to 800% by weight, more preferably 100 to 500% by weight of the electron-donating colorless dye.

Examples of the electron-donating colorless dyes include triphenylmethanephthalide compounds, fluorane compounds, phenothiazine compounds, indolylphthalide compounds, leucoauramine compounds, rhodaminelactam compounds, triphenylmethane compounds. , Triazene compounds, spiropyran compounds, fluorene compounds, and the like. Specific examples of the phthalides are US Reissue Patent Specification No. 23,024 and US Patent Specification No. 3,49.
No. 1,111, No. 3,491,112, No. 3,4
91,116 and 3,509,174, specific examples of fluoranes are described in U.S. Pat. No. 3,624,10.
No. 7, No. 3,627,787, No. 3,641,0
No. 11, No. 3,462,828, No. 3,681,
No. 390, No. 3,920,510, No. 3,95
9,571, specific examples of spirodipyrans are US Pat. No. 3,971,808, and pyridine-based and pyrazine-based compounds are US Pat. No. 3,775,424.
No. 3,853,869, No. 4,246,31
No. 8, specific examples of fluorene compounds are disclosed in JP-A-63-94.
No. 878 and the like. In the present invention, preferred electron donating colorless dyes include fluoran compounds represented by the following general formula (2).

[0020]

[Chemical 6]

In the above general formula, R ₂ and R ₃ represent an alkyl group or an aryl group, and R ₄ , R ₅ and R ₆ represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group.

Of these, 2-arylamino-3-H, which has a black color, and halogen or alkyl-6-substituted aminofluorane are particularly effective. Specific examples include, for example, 2-anilino-3-methyl-6-diethylaminofluorane, 2-
Anilino-3-methyl-6-N-cyclohexyl-N-
Methylaminofluorane, 2-p-chloroanilino-3
-Methyl-6-dibutylaminofluorane, 2-anilino-3-chloro-6-diethylaminofluorane, 2-
Anilino-3-methyl-6-N-ethyl-N-isoamylaminofluorane, 2-anilino-3-methyl-6-
N-ethyl-N-dodecylaminofluorane, 2-o-
Chloroanilino-6-dibutylaminofluorane, 2-
Anilino-3-pentadecyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-dibutylaminofluorane, 2-o-toluidino-3-methyl-6-
Diisopropylaminofluorane, 2-anilino-3-
Methyl-6-N-isobutyl-N-ethylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N
-Tetrahydrofurfurylaminofluorane, 2-anilino-3-chloro-6-N-ethyl-N-isoamylaminofluorane, 2-anilino-3-methyl-6-N-
Methyl-N-γ-ethoxypropylaminofluorane,
2-anilino-3-methyl-6-N-ethyl-N-γ-
Ethoxypropylaminofluorane, 2-anilino-3
-Methyl-6-N-ethyl-N-γ-propoxypropylaminofluorane, 2-anilino-3-methyl-6-
N-methyl-N-propylaminofluorane and the like can be mentioned. Among these, 2-anilino-3-methyl-6-
Dibutylaminofluorane is preferable, and 2-anilino-3-methyl-6-N-methyl-Nn-propylaminofluorane is particularly preferable.

A sensitizer may be added in addition to the electron-donating colorless dye and the electron-accepting compound. Examples of the sensitizer include JP-A-58-57989, JP-A-58-87094,
The compounds disclosed in JP-A-63-39375 and the like can be mentioned. Aromatic ethers (especially benzyl ethers, di (substituted phenoxy) alkanes, diphenyl ethers, particularly preferably 2-benzyloxynaphthalene, 1,2-di (3-methylphenoxy) ethane, 4-
Biphenyl-p-tolyl ether), aromatic ester (especially dibenzyl oxalate derivative, particularly preferably di (p-methylbenzyl oxalate)), biphenyl derivative (especially parabenzyl biphenyl, metaterphenyl) or fat The group amides, ureas or aromatic amides or ureas are representative. The sensitizer is preferably used in an amount of 50 to 800% by weight of the electron-donating colorless dye, more preferably 100 to 500% by weight. Two or more sensitizers may be used in combination. In particular, it is preferable to use an aliphatic amide or urea together with a sensitizer of an aromatic ether, an aromatic ester or a biphenyl derivative.
Examples of the aliphatic amide and urea include those represented by the general formula (3):
Those mentioned in (5) are preferable.

[0024]

[Chemical 7]

In the above general formula, R ₇ has 12 to 12 carbon atoms.
An alkyl or alkenyl group of 24, R ₈ is a hydrogen atom, an alkyl group or methylol group having 1 to 24 carbon atoms, R ₉ represents an alkylene group having 1 to 8 carbon atoms.

Specific examples thereof include stearic acid amide, palmitic acid amide, oleic acid amide, stearyl urea and palmityl urea. Further, N-substituted amide compounds such as methylol stearic acid amide and ethylenebisstearic acid amide are also included. The addition amount of these amide compounds or urea compounds is 1 to 1 with respect to the sensitizer of aromatic ether, aromatic ester or biphenyl derivative.
00 wt% is preferred. More preferably, it is 2 to 50% by weight.

Next, a method for producing a typical thermosensitive coloring layer of the present invention will be described. Electron-donating colorless dye, electron-accepting compound,
The sensitizer is dispersed with a water-soluble polymer aqueous solution such as polyvinyl alcohol to a particle size of several microns or less using a ball mill, a sand mill or the like. The sensitizer is an electron-donating colorless dye,
In addition to either or both of the electron-accepting compounds, they may be dispersed simultaneously, or in some cases, a eutectic with an electron-donating colorless dye or an electron-accepting compound may be prepared and dispersed. These dispersions are mixed after dispersion, and if necessary, pigments, surfactants, binders, metal soaps, waxes,
Antioxidant, ultraviolet absorber, etc. are added to make a heat-sensitive coating liquid. The heat-sensitive coating liquid obtained is a high-quality paper, a high-quality paper having an undercoat layer,
After being applied and dried on synthetic paper, plastic film, etc.,
The calendering process imparts smoothness to the target thermal recording material.

The support used in the present invention is JI
It is particularly preferable to use a support having a smoothness defined by S-8119 of 500 seconds or more, particularly 800 seconds or more, from the viewpoint of dot reproducibility. In order to obtain a support having a smoothness of 500 seconds or more, (1) a highly smooth one such as synthetic paper or a plastic film is used, and (2) an undercoat layer containing a pigment as a main component is provided on the support. (3) means for increasing the smoothness of the support by using a super calender or the like.

It has been found that the provision of an undercoat layer containing a pigment as a main component makes it difficult for the white background to be fogged when stored at a high temperature in addition to the dot reproducibility. In the present invention, as the pigment used in the undercoat layer, calcined kaolin, aluminum hydroxide, calcium carbonate, barium sulfate, zinc oxide, lithopone, wax stone, kaolin, silica,
There are amorphous silica and the like. Two or more of these pigments may be used in combination. Particularly preferred is calcined kaolin.

The undercoat layer coating liquid is obtained by mixing the pigment dispersion with a binder. Further, a release agent, a waterproofing agent, a surfactant, a sizing agent, a wax, etc. may be added, if necessary. In particular, the addition of sizing agents such as alkenyl succinates, alkyl ketene dimers and rosin compounds, and water repellents such as paraffin wax, microcrystalline wax, carnauba wax, montan wax, and polyethylene wax will further improve the preservability of white areas. . The amount of the sizing agent and the water repellent used is 0.2 to 20% by weight, preferably 0.5 to 5% by weight, based on the pigment contained in the undercoat layer. The obtained undercoat layer coating liquid is applied and dried on a support using an apparatus such as a bar coater, an air knife coater, a blade coater or a curtain coater to obtain the undercoat layer of the present invention. A thermosensitive coloring layer is coated on the undercoating layer thus provided to obtain a thermosensitive recording material. The undercoat layer may be applied simultaneously with the heat-sensitive color forming layer, or after the undercoat layer is applied, the undercoat layer may be dried once and then the heat-sensitive color developing layer may be applied. The dry coating amount of the undercoat layer is preferably 3.0 to 20.0 g / m ² , and more preferably 5.0 to 12.0 g / m ² . When the coating amount is small, the thermal sensitivity is remarkably lowered, and when the coating amount is large, the coating film strength and the paper strength are insufficient. After applying the undercoat layer and after applying the heat-sensitive color forming layer, a calendering treatment may be carried out if necessary.

In the present invention, a protective layer may be provided if necessary. Examples of pigments include aluminum hydroxide, calcium carbonate, barium sulfate, zinc oxide, lithopone, wax, kaolin, silica, and amorphous silica. Two or more of these pigments may be used in combination. In particular, it is preferable to use aluminum hydroxide because when the surface of the thermal paper is written with a pencil, the surface is less likely to slip and the sensitivity is less likely to decrease.

The protective layer coating liquid of the present invention is obtained by mixing a pigment dispersion with a binder. If necessary, a release agent,
A water resistant agent, a surfactant, a wax and the like may be added. The protective layer coating liquid thus obtained is applied and dried on the thermosensitive color developing layer using an apparatus such as a bar coater, an air knife coater, a blade coater or a curtain coater to obtain the protective layer of the present invention. The protective layer may be applied at the same time as the heat-sensitive color forming layer, or may be applied after the heat-sensitive color forming layer is applied and then dried. The dry coating amount of the protective layer is preferably 0.5 to 5.0 g / m ² , and more preferably 0.8 to 3.0 g / m ² . When the coating amount is large, the thermal sensitivity is remarkably reduced, and when the coating amount is small, the protective effect is not sufficient. After applying the protective layer, a calendering treatment may be performed if necessary.

As the binder used in the present invention,
A compound that is soluble in 5% by weight or more in water at 25 ° C. is preferable. Specifically, polyvinyl alcohol (including modified polyvinyl alcohol such as carboxy-modified, acetoacetyl-modified, itaconic acid-modified, maleic acid-modified, and silica-modified) , Methyl cellulose, carboxymethyl cellulose, starches (including modified starch), gelatin, gum arabic, casein, styrene-maleic anhydride copolymer hydrolyzate, polyacrylamide, saponified vinyl acetate-polyacrylic acid copolymer, etc. Can be given. These binders are used not only for dispersion but also for the purpose of improving the coating strength.
A latex binder of a synthetic polymer such as a butadiene copolymer, a vinyl acetate copolymer, an acrylonitrile / butadiene copolymer, a methyl acrylate / butadiene copolymer, or polyvinylidene chloride may be used in combination. Further, if necessary, a crosslinking agent for a suitable binder may be added depending on the kind of the binder.

Examples of the pigment used in the present invention include calcium carbonate, barium sulfate, lithopone, wax, kaolin, silica and amorphous silica. As the metal soap, higher fatty acid metal salt is used, zinc stearate,
Calcium stearate, aluminum stearate, etc. are used. Further, a surfactant, an antistatic agent, an ultraviolet absorber, an antifoaming agent, a conductive agent, a fluorescent dye, a coloring dye, etc. may be added if necessary.

When the salicylic acid derivative of the present invention and the metal salt thereof are used, the chemical resistance of the white background and the image area is very good, but the ultraviolet absorption in order to improve the discoloration of the white background against light. By adding the agent, the light resistance of the white background can be improved. The ultraviolet absorber may be added to the thermosensitive coloring layer, to the undercoat layer, to the back layer, or to the protective layer, but it should be added to the coloring layer or the protective layer. Is preferred. When it is added to the protective layer, a protective layer containing no ultraviolet absorber may be further provided thereon.

A benzophenone-based ultraviolet absorber,
There are benzotriazole-based, cyanoacrylate-based, and hindered amine-based UV absorbers, and among them, benzotriazole-based UV absorbers are preferable. Particularly, a benzotriazole compound represented by the following general formula (6) is particularly preferable.

[0037]

[Chemical 8]

In the above formula, R _10, R ₁₁ and R ₁₂ are a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, an alkoxy group,
Represents an aralkyl group, an aryl group or a halogen atom,
These may have a substituent further.

Specific examples include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole and 2- (2'-hydroxy-5'-methylphenyl) benzotriazole.
(2′-hydroxy-5′-tert-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-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-sec-
Butyl-5′-tert-butylphenyl) benzotriazole, 2- {2′-hydroxy-3 ′, 5′-di (α, α-dimethylbenzyl) phenyl} benzotriazole, 2- (2′-hydroxy-3) ', 5'-Gee t
ert-amylphenyl) benzotriazole, 2-
(2'-Hydroxy-3'-dodecyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-4 '-(2 "-ethylhexyl) oxyphenyl) benzotriazole, 2- (2'-hydroxy) -5'-t
ert-octylphenyl) benzotriazole, methyl-3- {3-tert-butyl-5- (2H-benzotriazol-2-yl) -4-hydroxyphenyl}
Propionate polyethylene glycol (molecular weight about 3
00) solutions and the like. The amount of the ultraviolet absorber used is 10 to 500 of the electron-donating colorless dye in the thermosensitive coloring layer.
It is preferable to use 50% by weight, more preferably 50%
~ 400% by weight.

Even if the UV absorber is used in a solid dispersion,
Further, from the viewpoint that a substance having a low melting point or a substance having a liquid at room temperature can be used, it may be contained in a microcapsule for use. The microcapsules used in the present invention can be prepared by various known methods, and generally, a core substance (oily liquid) obtained by dissolving an ultraviolet absorber in an organic solvent as necessary is emulsified and dispersed in an aqueous medium. Then, it is adjusted by a method of forming a wall film made of a polymer substance around the oily droplets. Specific examples of the polymer substance that becomes the wall film of the microcapsule include:
Examples thereof include polyurethane resin, polyurea 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.
Examples of the organic solvent used for the core substance include oils used for pressure-sensitive recording materials and low boiling point solvents such as ethyl acetate and butyl acetate.

In the present invention, when the ultraviolet absorbent is added to the protective layer, the ultraviolet absorbent dispersion or the capsule containing the ultraviolet absorbent is mixed with the pigment dispersion and the binder to obtain a protective layer coating liquid. Further, a release agent, a waterproofing agent, a surfactant, a wax and the like may be added if necessary. The protective layer coating liquid thus obtained is applied and dried on the thermosensitive color developing layer using an apparatus such as a bar coater, an air knife coater, a blade coater or a curtain coater to obtain the protective layer of the present invention. The protective layer may be applied at the same time as the heat-sensitive color forming layer, or may be applied after the heat-sensitive color forming layer is applied and then dried.
If necessary, a protective layer containing no ultraviolet absorber may be provided on the protective layer containing the ultraviolet absorber. The dry coating amount of the protective layer is preferably 0.5 to 5.0 g / m ² , and more preferably 0.8 to 3.0 g / m ² . When the coating amount is large, the thermal sensitivity is remarkably reduced, and when the coating amount is small, the protective effect is not sufficient. After applying the protective layer, a calendering treatment may be performed if necessary.

Further, if necessary, a back coat layer may be provided on the surface of the support of the thermosensitive recording material opposite to the thermosensitive coloring layer. As the back coat layer, any one known as a back coat layer of a thermal recording material can be used. Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the examples.

[0043]

【Example】

(Example-1) 2-anilino-3-methyl-6-dibutylaminofluorane as an electron-donating colorless dye, oxalic acid di (p-methylbenzyl) ester as a sensitizer,
20 g of each was dispersed together with 100 g of an aqueous solution of 5% polyvinyl alcohol (Kuraray PVA-105) in a ball mill for a whole day and night so that the average particle diameter was 1.5 μm or less to obtain each dispersion. Also, 20 g of 4-benzyloxycarbonylaminosalicylic acid as an electron-accepting compound was added to 5 g of zinc oxide.
Was mixed with 100 g of a 5% aqueous solution of polyvinyl alcohol (Kuraray PVA-105) in a ball mill for 24 hours to obtain an electron-accepting compound dispersion having an average particle size of 1.5 μm or less. Further, 80 g of calcium carbonate was dispersed with 160 g of a 0.5% sodium hexametaphosphate solution by a homogenizer to obtain a pigment dispersion liquid. 5 g of each of the dispersions prepared as described above was used as an electron-donating colorless dye dispersion, 5 g of an electron-accepting compound dispersion, 10 g of an oxalic acid di (p-methylbenzyl) ester dispersion, and 5 g of a calcium carbonate dispersion. Then, 3 g of a 21% zinc stearate emulsion was added to obtain a heat-sensitive coating liquid. This thermosensitive color-developing layer coating solution was applied to a high-quality paper having a basis weight of 50 g / m ² using a wire bar so that the dry weight of the coating layer was 5 g / m ² , and dried at 50 ° C. for 1 minute to prepare a thermosensitive recording paper. Got

(Example-2) In the preparation of Example-1, except that 4-n-octyloxycarbonylaminosalicylic acid was used instead of 4-benzyloxycarbonylaminosalicylic acid to prepare a heat-sensitive coating liquid. A heat-sensitive recording paper was obtained by the same method.

Example 3 In the preparation of Example 1, 4-n-hexyloxycarbonylaminosalicylic acid was used instead of 4-benzyloxycarbonylaminosalicylic acid to prepare a heat-sensitive coating solution. A heat-sensitive recording paper was obtained by the same method.

(Example-4) In the preparation of Example-1, a heat-sensitive coating liquid was prepared by using 4-n-decyloxycarbonylaminosalicylic acid instead of 4-benzyloxycarbonylaminosalicylic acid. A heat-sensitive recording paper was obtained by the same method.

(Example-5) In the preparation of Example-1, a heat-sensitive coating liquid was prepared by using 4-p-tolyloxycarbonylaminosalicylic acid instead of 4-benzyloxycarbonylaminosalicylic acid. A heat-sensitive recording paper was obtained by the same method.

(Example-6) The same procedure as in Example-1 was repeated except that 5-benzyloxycarbonylaminosalicylic acid was used instead of 4-benzyloxycarbonylaminosalicylic acid to prepare a heat-sensitive coating solution. A heat sensitive recording paper was obtained by the method described in 1.

(Example-7) In the preparation of Example-1, 5-n-octyloxycarbonylaminosalicylic acid was used in place of 4-benzyloxycarbonylaminosalicylic acid to prepare a heat-sensitive coating solution. A heat-sensitive recording paper was obtained by the same method.

(Example-8) Thermal recording was carried out in the same manner as in Example-1, except that the amount of zinc oxide used was changed to 2 g to prepare an electron-accepting compound dispersion liquid to prepare a heat-sensitive coating liquid. Got the paper.

(Example-9) A heat-sensitive recording was conducted in the same manner as in Example-1, except that the amount of zinc oxide used was changed to 10 g to prepare an electron-accepting compound dispersion liquid to prepare a heat-sensitive coating liquid. Got the paper.

Example 10 The procedure of Example 1 was repeated except that 2-benzyloxynaphthalene was used instead of oxalic acid di (p-methylbenzyl) ester to prepare a heat-sensitive coating solution. A thermal recording paper was obtained by the same method.

Example 11 The same procedure as in Example 1 was repeated except that parabenzyl biphenyl was used instead of oxalic acid di (p-methylbenzyl) ester to prepare a heat-sensitive coating solution. Thermal recording paper was obtained by the method.

(Example-12) The same procedure as in Example-1 was carried out except that a heat-sensitive coating solution was prepared using metaterphenyl instead of using oxalic acid di (p-methylbenzyl) ester. Thermal recording paper was obtained by the method.

Example 13 A heat-sensitive coating solution was prepared by using 4-biphenyl-p-tolyl ether instead of using oxalic acid di (p-methylbenzyl) ester in the preparation of Example-1. A heat-sensitive recording paper was obtained by the same method as above.

Example 14 In the preparation of Example-1, 1,2-di (3-methylphenoxy) ethane was used in place of the oxalic acid di (p-methylbenzyl) ester to obtain a heat-sensitive substance. A thermal recording paper was obtained by the same method except that the coating liquid was prepared.

(Example-15) The same procedure as in Example-1 except that 2 g of a 21% stearic acid amide dispersion (High Micron G270 manufactured by Chukyo Yushi Co., Ltd.) was added to prepare a heat-sensitive coating solution. A heat sensitive recording paper was obtained by the method described in 1.

Example 16 In the preparation of Example-1, 2-benzyloxynaphthalene was used in place of oxalic acid di (p-methylbenzyl) ester, and a 22% methylol stearoamide dispersion was used. Heat-sensitive recording paper was obtained by the same method except that 2 g of a product (Hydrin D-130 manufactured by Chukyo Yushi Co., Ltd.) was added to prepare a heat-sensitive coating liquid.

Example 17 Instead of using 2-anilino-3-methyl-6-dibutylaminofluorane in the preparation of Example-1, 2-anilino-3-methyl-6-N-ethyl was used. A heat-sensitive recording paper was obtained by the same method except that the heat-sensitive coating liquid was prepared using -N-isoamylaminofluorane.

Example-18 Instead of using 2-anilino-3-methyl-6-dibutylaminofluorane in the preparation of Example-1, 2-anilino-3-methyl-6-N-methyl A thermosensitive recording paper was obtained by the same method except that the thermosensitive coating liquid was prepared using -N-n-propylaminofluorane.

Example 19 Instead of using 2-anilino-3-methyl-6-dibutylaminofluorane in the preparation of Example-1, 2-o-chloroanilino-6-dibutylaminofluorane was used. A heat-sensitive recording paper was obtained by the same method except that a heat-sensitive coating liquid was prepared.

Example 20 A thermosensitive recording paper was obtained by using the undercoat paper prepared as described below in place of the high-quality paper having a basis weight of 50 g / m ² in the preparation of Example-1. (Preparation of undercoat 1) Calcined kaolin (Ansilex 9
80 g of Engelhardt) was dispersed with a homogenizer together with 160 g of a 0.5% sodium hexametaphosphate solution, and 100 g of a 10% polyvinyl alcohol (Kuraray PVA-105) aqueous solution was added to this dispersion to obtain an undercoat layer coating liquid. . The dry weight of the undercoat layer coating solution was applied to a fine paper having a basis weight of 50 g / m ² using a wire bar so that the dry weight of the undercoat layer was 7.
It was coated so as to be 0 g / m ² and dried at 50 ° C. for 1 minute to obtain an undercoat paper. The undercoated paper thus obtained was surface-treated with a calender and adjusted so that the smoothness was 300 ± 100 seconds as Beck's smoothness to obtain an undercoated paper.

(Example-21) The same procedure as in Example-20 except that 15 g of 15.5% alkyl ketene dimer compound (Size Pine K903 manufactured by Arakawa Chemical Co., Ltd.) was added to the undercoat layer coating solution to prepare an undercoating solution. A heat-sensitive recording material was obtained by the method described in 1.

Example-22 Alkyl ketene dimer compound of Example-21 (Size Pine K9 manufactured by Arakawa Chemical Co., Ltd.)
A thermosensitive recording material was obtained by the same method except that 12 g of an alkyl ketene dimer compound (Size Pine K287 manufactured by Arakawa Chemical Co., Ltd.) was used instead of 03) to prepare an undercoating liquid.

Example-23 Alkylketene dimer compound of Example-21 (Size Pine K9 manufactured by Arakawa Chemical Co., Ltd.)
A thermosensitive recording material was obtained by the same method except that an undercoating liquid was prepared by using 9 g of a 30% paraffin wax dispersion liquid (Size Pine W116H manufactured by Arakawa Chemical Co., Ltd.) instead of 03).

Example-24 Alkylketene dimer compound of Example-21 (Size Pine K9 manufactured by Arakawa Chemical Co., Ltd.)
A thermosensitive recording material was obtained by the same method except that an undercoating liquid was prepared by using 9 g of a 30% paraffin wax dispersion liquid (Hidrin D-337 manufactured by Chukyo Yushi Co., Ltd.) instead of using 03).

Example-25 Alkylketene dimer compound of Example-21 (Size Pine K9 manufactured by Arakawa Chemical Co., Ltd.)
A thermosensitive recording material was obtained by the same method except that an undercoating liquid was prepared by using 9 g of a 30% paraffin wax dispersion liquid (Hidrin P-7 manufactured by Chukyo Yushi Co., Ltd.) instead of 03).

Example-26 The alkylketene dimer compound of Example-21 (Size Pine K9 manufactured by Arakawa Chemical Co., Ltd.)
A heat-sensitive recording material was obtained by the same method except that the undercoating coating solution was prepared by using 9 g of 30% reinforced rosin size agent (Size Pine E manufactured by Arakawa Chemical Industries Co., Ltd.) instead of using 03).

(Example-27) The alkylketene dimer compound of Example-21 (Size Pine K9 manufactured by Arakawa Chemical Co., Ltd.)
A thermosensitive recording material was obtained by the same method except that 6 g of a potassium salt (40%) of a compound having an alkenyl group having 12 carbon atoms was used instead of 03) to prepare an undercoating liquid.

(Example-28) A heat-sensitive material was prepared in the same manner as in Example-21, except that calcium carbonate (Callite KT, Shiraishi Central Research Laboratories) was used instead of the calcined kaolin of Example-21 to prepare an undercoating solution. I got the recording paper.

Example-29 Instead of using the calcined kaolin of Example-21, amorphous silica (Mizuka) is used.
Sil P-832, Mizusawa Kagaku Co., Ltd.) was used to obtain a thermosensitive recording paper by the same method except that an undercoating liquid was prepared.

(Example-30) Instead of using 80 g of calcined kaolin of Example-21, 70 g of calcined kaolin +
A heat-sensitive recording paper was obtained by the same method except that the heat-sensitive coating liquid was prepared using 10 g of calcium carbonate.

Example-31 Instead of using 80 g of calcined kaolin of Example-21, 60 g of calcined kaolin +
A thermosensitive recording paper was obtained by the same method except that the thermosensitive coating liquid was prepared using 20 g of calcium carbonate.

(Example-32) On the thermosensitive recording paper obtained in Example 1, the protective layer coating liquid 1 obtained by the following method was applied using a wire bar so that the dry weight of the protective layer was 2.0 g / m ^2. To obtain a heat-sensitive recording paper. (Preparation of Protective Layer Coating Liquid 1) 80 g of aluminum hydroxide (Showa Denko Hygilite H42) was dispersed in a homogenizer together with 160 g of a 0.5% sodium hexametaphosphate solution,
10% polyvinyl alcohol (Kuraray PV
A-105) Aqueous solution 800 g and 21% zinc stearate emulsion 100 g were added to obtain a protective layer coating liquid.

(Example-33) Instead of using 80 g of aluminum hydroxide of Example-32, 60 g of aluminum hydroxide + 20 g of kaolin (Shiroishi Kogyo Kablite) 20 g
A heat-sensitive recording paper was obtained by the same method except that the heat-sensitive coating liquid was prepared using.

(Example-34) A thermosensitive recording paper was prepared in the same manner as in Example-32 except that 40 g of aluminum hydroxide + 40 g of kaolin was used instead of 80 g of aluminum hydroxide to prepare a thermosensitive coating solution. Obtained.

(Example-35) Instead of using 80 g of aluminum hydroxide of Example-32, 60 g of aluminum hydroxide + calcium carbonate (Shiroishi Kogyo Unibur 7
0) A thermosensitive recording paper was obtained by the same method except that 20 g of the thermosensitive coating liquid was prepared.

(Example-36) In the preparation of Example-32, 2- (2'-hydroxy-) was used as an ultraviolet absorber.
20 g of 5'-methylphenyl) benzotriazole
00g of 5% polyvinyl alcohol (Kuraray PVA-1
05) A heat-sensitive recording paper was obtained by the same method except that the heat-sensitive coating liquid was prepared by adding 10 g of a dispersion obtained by dispersing the solution with an aqueous solution by a ball mill all day and night to give an average particle size of 1.5 μm or less.

(Example-37) The same procedure as in Example-36 was repeated except that the amount of added 2- (2'-hydroxy-5'-methylphenyl) benzotriazole was changed to 5 g to prepare a heat-sensitive coating solution. Thermal recording paper was obtained by the method.

(Example-38) The same procedure as in Example-36 was repeated except that the amount of added 2- (2'-hydroxy-5'-methylphenyl) benzotriazole was changed to 15 g to prepare a heat-sensitive coating solution. Thermal recording paper was obtained by the method.

(Example-39) The same procedure as in Example-36 was repeated except that the addition amount of 2- (2'-hydroxy-5'-methylphenyl) benzotriazole was changed to 50 g to prepare a heat-sensitive coating solution. Thermal recording paper was obtained by the method.

Example-40 Instead of using 2- (2'-hydroxy-5'-methylphenyl) benzotriazole in the preparation of Example-36, 2-
A thermosensitive recording paper was obtained by the same method except that the thermosensitive coating liquid was prepared using (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole.

Example-41 Instead of using 2- (2'-hydroxy-5'-methylphenyl) benzotriazole in the preparation of Example-36, 2-
(2'-hydroxy-3'-tert-butyl-5'-
A thermosensitive recording paper was obtained by the same method except that a thermosensitive coating liquid was prepared using methylphenyl) -5-chlorobenzotriazole.

Example-42 Instead of using 2- (2'-hydroxy-5'-methylphenyl) benzotriazole in the preparation of Example-36, 2-
A thermosensitive recording paper was obtained by the same method except that the thermosensitive coating liquid was prepared by using (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole.

(Example-43) A thermosensitive recording paper was obtained without coating the protective layer of Example-36.

(Example-44) A thermosensitive recording paper was obtained without applying the protective layer of Example-42.

(Example-45) The protective layer coating liquid 2 obtained by the following method was applied onto the thermosensitive recording paper obtained in Example 1 by using a wire bar so that the dry weight of the protective layer was 3.0 g / m ^2. To obtain a heat-sensitive recording paper. (Preparation of Coating Liquid 2 for Protective Layer) 2- (2 ′) as an ultraviolet absorber
-Hydroxy-5'-methylphenyl) benzotriazole 20 g was dispersed together with 100 g of a 5% aqueous solution of polyvinyl alcohol (Kuraray PVA-105) in a ball mill for a whole day and night so that the average particle diameter was 1.5 μm or less to obtain an ultraviolet absorbent dispersion. It was 50 g of a dispersion prepared by dispersing 80 g of aluminum hydroxide (Showa Denko Hydilite H42) in 160 g of this dispersion together with 160 g of a 0.5% solution of sodium hexametaphosphate with a homogenizer, and adding 10% polyvinyl alcohol (Kuraray PVA-105) aqueous solution to this dispersion. 200
g, 20 g of 21% zinc stearate emulsion was added to obtain a protective layer coating liquid 2.

(Example-46) The same procedure as in Example-45 except that the amount of 2- (2'-hydroxy-5'-methylphenyl) benzotriazole added was changed to 30 g to prepare a protective layer coating solution. A heat sensitive recording paper was obtained by the method described in 1.

(Example-47) The same procedure as in Example-45 except that the protective layer coating solution was prepared by changing the amount of 2- (2'-hydroxy-5'-methylphenyl) benzotriazole added to 50 g. A heat sensitive recording paper was obtained by the method described in 1.

(Example-48) The same procedure as in Example-45 was repeated except that the amount of 2- (2'-hydroxy-5'-methylphenyl) benzotriazole added was changed to 150 g to prepare a protective layer coating solution. A heat sensitive recording paper was obtained by the method described in 1.

Example-49 Instead of using 2- (2'-hydroxy-5'-methylphenyl) benzotriazole in the preparation of Example-45, 2-
A heat-sensitive recording paper was obtained by the same method except that the protective layer coating solution was prepared using (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole.

Example-50 Instead of using 2- (2'-hydroxy-5'-methylphenyl) benzotriazole in the preparation of Example-45, 2-
(2'-hydroxy-3'-tert-butyl-5'-
A thermal recording paper was obtained by the same method except that the protective layer coating liquid was prepared using methylphenyl) -5-chlorobenzotriazole.

Example-51 Instead of using 2- (2'-hydroxy-5'-methylphenyl) benzotriazole in the preparation of Example-45, 2-
A thermosensitive recording paper was obtained by the same method except that the protective layer coating liquid was prepared using (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole.

Example-52 Instead of using 100 g of 2- (2'-hydroxy-5'-methylphenyl) benzotriazole dispersion in the preparation of Example-45, 2- (2'-hydroxy- 3'-dodecyl-5 '
-Methylphenyl) benzotriazole capsule liquid (1
0% polyvinyl alcohol (PVA-217E) 100
g to ethyl 8 g, 2- (2'-hydroxy-3'-
30 g of dodecyl-5'-methylphenyl) benzotriazole and 40 g of xylidene diisocyanate-trimethylolpropane adduct (Takenate D-110N) solution were mixed with each other and emulsified with a homogenizer at 60 ° C.
Microcapsule dispersion having a wall film made of polyurethane-polyurea resin reacted for 2 hours and having a particle size of 3 μm)
A thermosensitive recording paper was obtained by the same method except that the protective layer coating liquid was prepared using 200 g.

(Example-53) Instead of using 20 g of 4-benzyloxycarbonylaminosalicylic acid as the electron-accepting compound in the preparation of Example-1,
Using 10 g of octylcarbonylaminosalicylic acid,
10 g of 4- [2 ′-(4-methoxyphenyloxy) ethyloxy] salicylic acid was used, and 21% stearic acid amide dispersion (manufactured by Chukyo Yushi Co., Ltd. High Micron G
270) 2 g was added to prepare a heat-sensitive coating liquid, and a heat-sensitive recording paper was obtained by the same method.

(Example-54) Instead of using 2-anilino-3-methyl-6-dibutylaminofluorane as the electron-donating colorless dye in the preparation of Example-1, 2-anilino-3-methyl- 6-N-methyl-N-propylaminofluorane is used, 2-benzyloxynaphthalene is used instead of oxalic acid di (p-methylbenzyl) ester as a sensitizer, and an electron-accepting compound As an alternative to using 20 g of 4-benzyloxycarbonylaminosalicylic acid as a mixture with 5 g of zinc oxide and using 100 g of a 5% polyvinyl alcohol (Kuraray PVA-105) aqueous solution, which was dispersed in an electron accepting compound dispersion in a ball mill all day and night, 8 g of zinc octylcarbonylaminosalicylate, 4- [2 '-(4-methoxyphenyloxy ) Ethyloxy] salicylic acid 8
g, 2 g of zinc oxide, 4 g of 2-2-bis- (4-hydroxyphenyl) propane were mixed, and 100 g of 5% polyvinyl alcohol (Kuraray PVA-105) aqueous solution was dispersed in a ball mill all day and night to obtain an electron accepting compound dispersion liquid. use. Further, a thermosensitive recording paper was obtained by the same method except that 2 g of a 21% stearic acid amide dispersion (High Micron G270 manufactured by Chukyo Yushi Co., Ltd.) was added to prepare a thermosensitive coating solution.

(Example-55) In the preparation of Example-54, 2,2-bis- was used as the electron-accepting compound dispersion.
A thermosensitive recording paper was obtained by the same method except that the thermosensitive coating liquid was prepared by using 1,4-bis- (4′-hydroxycumyl) benzene instead of using (4-hydroxyphenyl) propane. .

(Example-56) In the preparation of Example-54, 2,2-bis- was used as the electron-accepting compound dispersion.
A heat-sensitive recording paper was obtained by the same method except that a heat-sensitive coating liquid was prepared by using 4- (4-isopropoxyphenylsulfonyl) phenol instead of using (4-hydroxyphenyl) propane.

Comparative Example-1 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that bisphenol A was used instead of 4-benzyloxycarbonylaminosalicylic acid to prepare a thermosensitive coating solution. It was

Comparative Example 2 By the same method as in Example 1, except that 4-benzyloxycarbonylaminosalicylic acid in Example 1 was used, 4-hydroxybenzoic acid benzyl ester was used to prepare a heat-sensitive coating liquid. A thermosensitive recording paper was obtained.

(Comparative Example 3) A heat-sensitive coating solution was prepared by using 4- (4-isopropoxyphenylsulfonyl) phenol instead of 4-benzyloxycarbonylaminosalicylic acid of Example-1. A heat-sensitive recording paper was obtained by the same method.

The thermal recording paper obtained as described above is
Surface treatment was performed with a calender, and the smoothness was adjusted to be Beck's smoothness of 300 ± 50 seconds to obtain a heat-sensitive recording material. The thermal recording paper was evaluated as follows. (1) Color density is 30 mJ / printing energy with a Kyocera printing tester
Printed in mm ² , and measured the color density with a Macbeth densitometer.
The higher this value, the higher the sensitivity of the thermal recording paper. (2)
In the chemical resistance test, a highlighter pen (PILOT Spotlighter Pink) was written on the color surface of the recording paper obtained by the above method to evaluate the degree of fog on the white background and decoloring (discoloration) of the color area. . (3) The light resistance test was carried out by using the recording paper obtained by the above method for direct sunlight for 1 week (Fujinomiya, 1
(Month) The white background density (Yellow density) and image density after irradiation were measured. (4) Heat resistance test was performed with 60 recording papers.
The white background density was measured after storing in a thermo-hygrostat at 30 ° C for 24 hours. (5) In the plasticizer resistance test, the recording paper obtained by the above method was contacted with Shin-Etsu's PVC wrap for 120 hours, and the degree of decoloration of the color-developed portion was evaluated. The above results are shown in Tables 1 to 4.

[0103]

[Table 1]

[0104]

[Table 2]

[0105]

[Table 3]

[0106]

[Table 4]

[0107]

As can be seen from the results of Tables 1 to 4, the recording material of the present invention has high sensitivity, does not cause fog color development or color part decolorization due to chemicals, and does not decolor the color part by a plasticizer. It can be seen that the image does not occur, the sharpness of the color-developed portion can be maintained, and the performance is extremely excellent.

Claims (9)

[Claims] 1. A thermosensitive recording material comprising a support and a thermosensitive coloring layer containing an electron-donating colorless dye and an electron-accepting compound, the salicylic acid derivative represented by the following general formula (1) being contained in the thermosensitive coloring layer. Or containing a metal salt and a metal compound,
A heat-sensitive recording material characterized by being in a solid dispersion state. [Chemical 1] In the above general formula, R ₁ represents an alkyl group or an aryl group, X represents a hydrogen atom, an alkyl group, an aryl group, an alkoxy group or a halogen atom, M represents a hydrogen atom or an n-valent metal atom, and n represents an integer. . 2. A heat-sensitive recording material comprising a support and a thermosensitive coloring layer containing an electron-donating colorless dye, an electron-accepting compound and a metal compound, wherein zinc oxide and the following general formula (2) are contained in the thermosensitive coloring layer. The heat-sensitive recording material according to claim 1, comprising a fluoran compound represented by: [Chemical 2] In the above general formula, R ₂ and R ₃ represent an alkyl group or an aryl group, and R ₄ , R ₅ and R ₆ represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. 3. A thermosensitive recording material in which a thermosensitive coloring layer containing an electron-donating colorless dye, an electron-accepting compound and a metal compound is provided on a support, wherein di (p-methylbenzyl oxalate) is contained in the thermosensitive coloring layer. , 2-benzyloxynaphthalene, parabenzyl biphenyl, metaterphenyl, 4-
Group consisting of biphenyl-p-tolyl ether, 1,2-di (3-methylphenoxy) ethane, aliphatic amide compound or aliphatic urea compound represented by the following general formulas (3), (4) and (5) The heat-sensitive recording material according to claim 1 or 2, further comprising a sensitizer selected from the following. [Chemical 3] In the above general formula, R ₇ is an alkyl group or an alkenyl group having 12 to 24 carbon atoms, and R ₈ is a hydrogen atom or 1 carbon atom.
~ 24 alkyl group or methylol group, R ₉ represents an alkylene group having 1 to 8 carbon atoms. 4. A thermosensitive coloring layer containing an electron-donating colorless dye, an electron-accepting compound and a metal compound on a support, and a thermosensitive recording material having a protective layer formed thereon, wherein aluminum hydroxide is contained in the protective layer. The heat-sensitive recording material according to claim 1, wherein the heat-sensitive recording material is contained. 5. A heat-sensitive recording material having a thermosensitive coloring layer containing an electron-donating colorless dye, an electron-accepting compound and a metal compound on a support, wherein an ultraviolet absorber represented by the following general formula (6) is used. It contains 1 to 4 characterized by the above-mentioned.
The heat-sensitive recording material described in. [Chemical 4] In the above general formula, R ₁₀ , R ₁₁ and R ₁₂ are hydrogen atoms,
It represents an alkyl group having 1 to 15 carbon atoms, an alkoxy group, an aralkyl group, an aryl group or a halogen atom. 6. A heat-sensitive recording material in which a subbing layer, a thermosensitive coloring layer containing an electron-donating colorless dye, an electron-accepting compound and a metal compound are sequentially provided on a support, wherein calcined kaolin, a sizing agent or a sizing agent is used in the subbing layer. At least 1 wax
The heat-sensitive recording material according to claim 1, further comprising a seed. 7. A heat-sensitive recording material having a thermosensitive coloring layer containing an electron-donating colorless dye, an electron-accepting compound and a metal compound on a support, wherein a salicylic acid derivative represented by the general formula (1) or the metal thereof is used. 7. The heat-sensitive recording material according to claim 1, comprising a salt and 4- [2 ′-(4-methoxyphenyloxy) ethyloxy] salicylic acid or the metal salt thereof. 8. A thermosensitive recording material comprising a support and a thermosensitive coloring layer containing an electron-donating colorless dye and an electron-accepting compound metal compound, which comprises 2,2-bis- (4-hydroxyphenyl) propane, The heat-sensitive recording material according to claim 7, which contains at least one of 4-, 4-bis- (4'-hydroxycumyl) benzene and 4- (4-isopropoxyphenylsulfonyl) phenol. 9. A thermosensitive recording material having a thermosensitive coloring layer containing an electron-donating colorless dye, an electron-accepting compound and a metal compound on a support, wherein the salicylic acid derivative represented by the general formula (1) is 4- 8. An n-octylcarbonylaminosalicylic acid or a metal salt thereof.
Or the heat-sensitive recording material described in 8 above.