JPH07144471A - Thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a thermal recording material having high sensitivity, good in raw preservability and imparting a developed color image good in stability by adding a specific N-substituted anthranilic acid derivative or a metal salt thereof and a hindered phenol compd. to a thermal color forming layer. 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, an N-substituted anthranilic acid derivative represented by either one of formulae I, II or a metal salt thereof and a hindered phenol compd. are added to the thermal color forming layer. In the formulae, R1 is a hydrogen atom, an alkyl group or an aryl group, R2 is an alkyl group, a cycloalkyl group, an aryl group, an alkylamino group, an alkyloxy group, an aryloxy group or an arylamino group, X is an oxygen atom or a sulfur atom, M is an n-valent metal atom and n is an integer. This thermal recording material has high sensitivity and does not cause fog color development due to chemicals and the erasure of a developed color part and has extremely excellent capacity.

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 specifically, it contains an electron-donating colorless dye and an electron-accepting compound which are improved in color developability, raw storability and stability of color image. The present invention relates to a heat-sensitive recording material provided with a color forming layer on a 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 found that the electron-donating colorless dye and the electron-accepting compound each have oil solubility, water solubility, partition coefficient, p
Focusing on Ka, the polarity of the substituents, and the positions of the substituents, we have pursued the development of good recording material materials and recording materials.

[0003]

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.

[0004]

The problem to be solved by the present invention is to provide a thermosensitive recording material comprising a support and a thermosensitive coloring layer containing an electron-donating colorless dye and an electron-accepting compound. To the following general formula (I) or (II)
This is achieved by a heat-sensitive recording material containing an N-substituted anthranilic acid derivative represented by the following formula or a metal salt thereof and containing a hindered phenol compound represented by the following general formulas.

[0005]

[Chemical 3]

[0006]

[Chemical 4]

(In the above formula, R ₁ is hydrogen atom, alkyl group or aryl group, R ₂ is alkyl group, cycloalkyl group, aryl group, alkylamino group, alkyloxy group, aryloxy group or arylamino group, X Is an oxygen atom or a sulfur atom, M is an n-valent metal atom, n
Represents an integer. )

In the general formula (I) or (II), R ₁ is preferably a hydrogen atom, a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 or 4 carbon atoms, and 6 to 6 carbon atoms. 10 monocyclic or condensed-ring aryl groups, R ₂ is a linear or branched alkyl group having 4 to 20 carbon atoms, a substituted alkyl group (substituents are an aryl group, a carboxyl group, a sulfo group, a sulfoamino group, an aryl group). Oxy group, alkoxy group, acylamino group, etc.), carbon number 5
9 cycloalkyl group, C 6-10 monocyclic or condensed-ring aryl group, substituted aryl group (as a substituent,
Examples thereof include an alkyl group having 1 to 20 carbon atoms, a hydroxyl group, an aryl group, a carboxyl group, a sulfo group, a sulfoamino group and an acylamino group. ), An alkylamino group having 1 to 20 carbon atoms, a substituted alkylamino group (the substituent includes an aryl group, a carboxyl group, a sulfo group, a sulfoamino group, an acylamino group, etc.), and an alkyloxy group having 1 to 20 carbon atoms. Group, a substituted alkyloxy group (as a substituent, an aryl group, a carboxyl group, a sulfo group, a sulfoamino group,
There are acylamino groups and the like. ), An aryloxy group having 1 to 20 carbon atoms, and a substituted aryloxy group (as the substituent,
Examples thereof include an alkyl group having 1 to 20 carbon atoms, a hydroxyl group, an aryl group, a carboxyl group, a sulfo group, a sulfoamino group and an acylamino group. ), An arylamino group having 6 to 10 carbon atoms, and a substituted arylamino group (the substituent has 1 carbon atom).
.About.20 alkyl groups, hydroxyl groups, carboxyl groups, sulfo groups, sulfoamino groups, acylamino groups and the like. ) Is mentioned. Particularly preferably, R ₁ is a hydrogen atom and R ₂
Is an alkyl group having 7 to 17 carbon atoms, an alkoxy-substituted alkyl group, an aryloxy-substituted alkyl group, a carbon number of 7 to 17
Alkyloxy group, aralkyloxy group, carbon number 6 to
18 aryl groups, alkyl-substituted aryl groups, carbon number 1
2 to 18 alkylamino groups.

Specific examples of the electron-accepting compound according to the present invention will be shown. (1) N-caproylanthranilic acid, (2)
N-pivaloylanthranilic acid, (3) N-capryloylanthranilic acid, (4) N- (2-ethylhexanoyl) anthranilic acid, (5) N-decanoylanthranilic acid, (6) N-lauroylanthranilic acid Acid, (7) N
-Myristoylanthranilic acid, (8) N-palmitoylanthranilic acid, (9) N-stearoylanthranilic acid, (10) N- (cyclohexylcarbonyl) anthranilic acid, (11) N- (p-toluenesulfonyl)
Anthranilic acid, (12) N- (isobutylsulfonyl) anthranilic acid, (13) N- (octylsulfonyl) anthranilic acid, (14) N- (2-ethylhexylsulfonyl) anthranilic acid, (15) N- (dodecylsulfonyl) Anthranilic acid, (16) N- (octadecylsulfonyl) anthranilic acid, (17) N- (dodecylbenzenesulfonyl) anthranilic acid, (18)
N- (dodecylsulfonyl) anthranilic acid, (19)
N- (mesitylenesulfonyl) anthranilic acid, (2
0) N- (2,4,6-triisopropylbenzenesulfonyl) anthranilic acid, (21) N- (octylcarbamoyl) anthranilic acid, (22) N- (2-ethylhexylcarbamoyl) anthranilic acid, (23) N-
(Cyclohexylcarbamoyl) anthranilic acid, (2
4) N- (dodecylcarbamoyl) anthranilic acid,
(25) N- (octadecylcarbamoyl) anthranilic acid, (26) N- (dodecylphenylcarbamoyl)
Anthranilic acid, (27) N- (cyclohexylthiocarbamoyl) anthranilic acid, (28) N- (octylthiocarbamoyl) anthranilic acid, (29) N- (2
-Ethylhexylthiocarbamoyl) anthranilic acid,
(30) N- (dodecylthiocarbamoyl) anthranilic acid,

(31) N- (octadecylthiocarbamoyl) anthranilic acid, (32) N- (hexadecylsulfonyl) anthranilic acid, (33) N-acetylanthranilic acid, (34) N-propionylanthranilic acid, (35) N- (n-butylcarbonyl) anthranilic acid, (36) N- (n-hexylcarbonyl) anthranilic acid, (37) N- (n-octylcarbonyl) anthranilic acid, (38) N-benzoylanthranilic acid, (39 ) N- (4-chlorobenzoyl) anthranilic acid, (40) N- (4-methoxybenzoyl) anthranilic acid, (41) N- (2-methoxybenzoyl) anthranilic acid, (42) N- (2-methylthiobenzoyl) ) Anthranilic acid, (43) N- (2-chlorobenzoyl) anthranilic acid (44) N- (phenoxyacetyl) anthranilic acid, (45) N- (4-methoxyphenoxyacetyl) anthranilic acid, (46) N- (phenylacetyl) anthranilic acid, (47) N- (phenoxycarbonyl) anthranilic acid , (48) N- (benzyloxycarbonyl) anthranilic acid, (49) N
-(2-phenoxypropionyl) anthranilic acid,
(50) N- (3-phenoxypropionyl) anthranilic acid, (51) N- (methoxyacetyl) anthranilic acid, (52) N- (methylsulfonyl) anthranilic acid, (53) N- (n-butylsulfonyl) anthranyl Acid, (54) N- (phenylsulfonyl) anthranilic acid, (55) N- (methoxycarbonyl) anthranilic acid, (56) N- (ethoxycarbonyl) anthranilic acid, (57) N- (n-butyloxycarbonyl) Anthranilic acid and the like can be mentioned. Particularly, N- (phenoxyacetyl) anthranilic acid and its metal salt are preferable.

On the other hand, the N-substituted anthranilic acid represented by the general formulas (I) and (II) of the present invention is converted into a polyvalent metal salt of its carboxyl group to obtain a remarkable color-developing ability which meets the object of the present invention. Indicates. In this case, the polyvalent metal is a typical element such as magnesium, calcium, aluminum or tin, or a transition element such as titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper or zinc. Particularly, as the polyvalent metal salt of N-substituted anthranilic acid represented by the general formula (I) or (II), a zinc salt or an aluminum salt is preferable. Among them, zinc salt has a high color developing ability. The N-substituted anthranilic acid derivatives represented by the general formulas (I) and (II) are oxides, hydroxides, carbonates and carboxylic acids of zinc, aluminum, titanium, silicon, boron, magnesium or calcium. When used in combination with one or more salts, 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 preferable, and zinc oxide is particularly preferable. According to the present invention, the N-substituted anthranilic acid derivative or its metal salt is preferably atomized to a particle size of 3 μm or less, preferably 2 μm or less, in order to obtain color development sensitivity, after being atomized by a sand mill or the like.

Even when the N-substituted anthranilic acid derivative or its metal salt is used as an electron-accepting compound, the image may be erased when a certain special polar solvent is attached. Although the cause of this is not clear, it has been found that the decoloring can be suppressed by adding the hindered phenol compound of the present invention. The hindered phenol compound of the present invention is one in which the activity of the phenolic hydroxyl group is suppressed by the alkyl group at the ortho position, and specifically, the compounds represented by the following general formulas (III) to (VI), etc. There is.

[0013]

[Chemical 5]

(Wherein R ¹ is a branched alkyl group having 3 to 8 carbon atoms, R ² is hydrogen or a branched alkyl group having 3 to 8 carbon atoms,
R ³ is hydrogen or an alkyl group having 1 to 3 carbon atoms, R ⁴ is hydrogen or an alkyl group having 3 to 8 carbon atoms, R ⁵ , R ⁶ , and R ⁷ are hydrogen or an alkyl group having 1 to 3 carbon atoms, R ⁸ Represents hydrogen or an alkyl group having 1 to 8 carbon atoms. )

[0015]

[Chemical 6]

(Wherein R ¹ and R ³ represent branched alkyl groups having 3 to 8 carbon atoms, R ² and R ⁴ represent alkyl groups having 1 to 8 carbon atoms,
Y is _{^{- (CR 5 R 6) n}} -, cyclohexylene or represents cyclopentylene radical, n is an integer of from 0 to 3,, R ^5,
R ⁶ represents hydrogen or an alkyl group having 1 to 8 carbon atoms. )

[0017]

[Chemical 7]

(Wherein R ¹ and R ⁴ are branched alkyl groups having 3 to 8 carbon atoms, R ² , R ³ , R ⁵ and R ⁶ are hydrogen or 1 to 8 carbon atoms)
When R ² and R ⁵ are hydrogen, R is
¹ and R ⁴ are the ortho positions of the hydroxyl group. Z is-(CR ⁷
R ⁸⁾ _n -, cyclohexylene or cyclopentylene group,, n represents an integer of 0~3, R ^7, R ⁸ represents hydrogen or an alkyl group having 1 to 8 carbon atoms. )

[0019]

[Chemical 8]

(Wherein R ¹ and R ² are branched alkyl groups having 3 to 8 carbon atoms, A is —NH—, —O (CH ₂ ) _n — (where n is an integer of 1 to 5). ) And i represent the integer of 1-4.
However, the W when i = 1 is an alkyl group having 1 to 18 carbon atoms, i = W when 2 ^{-S -, - (CR 3 R} 4) j - ( wherein R ^3, R ⁴ is hydrogen or In the alkyl group having 1 to 8 carbon atoms, j represents an integer of 0 to 8), and when i = 3, W is -C.
—R ⁵ (wherein R ⁵ represents hydrogen or an alkyl group having 1 to 8 carbon atoms), and when i = 4, W represents —C. )

Typical examples of the hindered phenols represented by the above general formulas (III) to (VI) are shown below. The hindered phenols represented by the general formula (III) include 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,1,3.
-Tris (2-ethyl-4-hydroxy-5-tert
-Butylphenyl) butane 1,1,3-tris (3,5
-Di-tert-butyl-4-hydroxyphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) propane and the like can be mentioned.

The hindered phenols represented by the general formula (IV) include 2,2'-methylene-bis- (6-
tert-butyl-4-methylphenol), 2,2 '
-Methylene-bis- (6-tert-butyl-4-ethylphenol) and the like.

The hindered phenols represented by the general formula (V) include 4,4'-butylidene-bis- (6-
(tert-butyl-3-methylphenol) and the like.

As the hindered phenols represented by the general formula (VI),

[0025]

[Chemical 9]

[0026]

[Chemical 10]

[0027]

[Chemical 11]

And the like. These may be used alone or in combination of two or more. The addition amount of these is preferably 5% by weight or more, more preferably 20% by weight or more, based on the N-substituted anthranilic acid derivative of the present invention or its metal salt. If the addition amount is 250% by weight or more, the color developability deteriorates. Further, as the phenol derivative, 1,1,3-tris (2-methyl-
4-Hydroxy-5-tert-butylphenyl) butane, 4,4′-butylidene-bis (6-tert-butyl-3-methylphenol) is particularly preferred.

The N-substituted anthranilic acid derivative according to the present invention has at least 1 at the ortho position of the phenolic hydroxyl group.
Salicylic acid derivatives, metal salts of aromatic carboxylic acids, which are already well known in phenolic compounds having one or more branched alkyl groups having 3 or more carbon atoms and an alkyl group which may have a substituent in the para position, An electron-accepting compound such as a phenol derivative, a phenol resin, a novolac resin, a metal-treated novolac resin, a metal complex, acid clay or bentonite may be used in combination. Examples of these are Japanese Patent Publication No. 40-93.
09, JP-B-45-14039, JP-A-52-14
0483, JP-A-48-51510, JP-A-57-
210886, JP-A-58-87089, JP-A-5
No. 9-112286, JP-A-60-176795, JP-A-61-95988 and the like.

Some examples of these are 4-tert-butylphenol, 4-phenylphenol, 2,
2'-dihydroxybiphenyl, 4,4'-sec-
Butylidene diphenol, bisphenol A, 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
There are -β-phenoxyethoxysalicylic acid, 4-β-p-ethylphenoxyethoxysalicylic acid, 4-β-p-methoxyphenoxyethoxysalicylic acid and the like, and metal salts thereof. The electron-accepting compound N- according to the present invention
The above electron-accepting compound is preferably mixed in a proportion of 10 to 100% by weight with respect to the substituted anthranilic acid derivative. Moreover, you may use together 2 or more types of said electron-accepting compounds.

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 dye of the present invention include triphenylmethanephthalide compounds, fluorane compounds, phenothiazine compounds, indolylphthalide compounds, leukoauramine compounds, rhodamine lactam compounds, There are various compounds such as triphenylmethane compounds, triazene compounds, spiropyran compounds, and fluorene compounds. Specific examples of the phthalides include US Reissue Patent Specification No. 23,024, US Patent Specification Nos. 3,491,111, and 3,491,112,
No. 3,491,116 and No. 3,509,17
No. 4, specific examples of fluoranes are described in US Pat.
No. 24,107, No. 3,627,787, No. 3,
No. 641,011, No. 3,462,828, No. 3,681,390, No. 3,920,510, No. 3,959,571, specific examples of spiro dipyrans are US patent specifications. No. 3,971,808, pyridine and pyrazine compounds are described in US Pat.
No. 5,424, No. 3,853,869, No. 4,2
46,318, and specific examples of fluorene compounds are described in Japanese Patent Application No. 61-240989. Among these, black aryl 2-arylamino-3-H, halogen or alkyl-6-substituted aminofluorane is particularly effective.

As a specific 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-anilino-3-ethyl-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-ethoxypropylaminofluor Oran, 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.

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 (particularly benzyl ethers, di (substituted phenoxy) alkanes), aromatic esters and / or aliphatic amides, ureas or aromatic amides or ureas are representative. In particular, aromatic esters are preferred, and oxalic acid dibenzyl ester derivatives are particularly preferred.

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. At this time, it is particularly preferable in terms of dot reproducibility to use a support having a smoothness defined by JIS-8119 of 500 seconds or more, particularly 800 seconds or more. 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.

As the binder, a compound that is soluble in 5% by weight or more in water at 25 ° C. is preferable.
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, Examples thereof include styrene-maleic anhydride copolymer hydrolyzate, polyacrylamide, and saponified vinyl acetate-polyacrylic acid copolymer. These binders are used not only during dispersion but also for the purpose of improving the coating strength. For this purpose, styrene / butadiene copolymer, vinyl acetate copolymer, acrylonitrile / butadiene copolymer, acrylic resin are used. Methyl acid-butadiene copolymer,
A latex binder of synthetic polymer such as polyvinylidene chloride may be used together. Further, if necessary, a crosslinking agent for a suitable binder may be added depending on the kind of the binder.

Examples of pigments include calcium carbonate, barium sulfate, lithopone, wax, kaolin, silica and amorphous silica.

As the metal soap, higher fatty acid metal salts are used, and zinc stearate, calcium stearate,
Aluminum stearate or the like is 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. The applied heat-sensitive recording material is dried and subjected to treatment with a calendar or the like before use. Further, a protective layer may be provided on the thermosensitive coloring layer, if necessary.

Any known protective layer can be used as the protective layer for the heat-sensitive recording material.

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.

[0041]

【Example】

(Example-1) 2-anilino-3-methyl-6-dibutylaminofluorane as an electron-donating colorless dye, zinc N- (phenoxyacetyl) anthranilate as an electron-accepting compound, and a hindered phenol compound,
1,1,3-tris (2-methyl-4-hydroxy-5)
-Tert-butylphenyl) butane, oxalic acid di (p-methylbenzyl) ester as a sensitizer, 20 g each
100 g of 5% polyvinyl alcohol (Kuraray PVA
-105) The mixture was dispersed with an aqueous solution for a whole day and night by a ball mill so that the average particle diameter was 1.5 μm or less, and each dispersion was obtained. In addition, 80 g of calcium carbonate was dispersed with a homogenizer together with 160 g of a 0.5% sodium hexametaphosphate solution,
A pigment dispersion was obtained. 5 g of the electron-donating colorless dye dispersion liquid, 10 g of the N- (phenoxyacetyl) anthranilic acid zinc dispersion liquid, 1, 1, 3
-Tris (2-methyl-4-hydroxy-5-tert)
-Butylphenyl) butane dispersion 3 g, oxalic acid di (p
-Methylbenzyl) ester dispersion liquid (10 g) and calcium carbonate dispersion liquid were mixed at a ratio of 5 g, and 3 g of 21% zinc stearate emulsion was added to obtain a heat-sensitive coating liquid. This thermosensitive color developing layer coating liquid was applied to a high-quality paper having a basis weight of 50 g / m ² by using a wire bar so that the dry weight of the coating layer was 5 g / m.
^It was applied so that it would be ² , and dried at 50 ° C. for 1 minute to obtain a thermosensitive recording paper.

(Example-2) 1, 1, 3-of Example-1
Tris (2-methyl-4-hydroxy-5-tert-
Instead of using butylphenyl) butane, 4,4 '
A heat-sensitive recording paper was obtained by the same method except that a heat-sensitive coating liquid was prepared by using -butylidene-bis (6-tert-butyl-3-methylphenol).

(Example-3) 1,1,3-of Example-1
Tris (2-methyl-4-hydroxy-5-tert-
2,2 'instead of using butylphenyl) butane
A heat-sensitive recording paper was obtained by the same method except that a heat-sensitive coating liquid was prepared by using -methylene-bis (6-tert-butyl-4-methylphenol).

Example 4 A heat-sensitive coating liquid was prepared by using N- (phenylacetyl) anthranilic acid instead of using zinc N- (phenoxyacetyl) anthranilic acid in the preparation of Example-1. A thermal recording paper was obtained by the same method except for the above.

Example 5 Instead of using zinc N- (phenoxyacetyl) anthranilate in the preparation of Example-1, N- (benzyloxycarbonyl)
A heat-sensitive recording paper was obtained by the same method except that the heat-sensitive coating liquid was prepared using zinc anthranilate.

(Example-6) In the preparation of Example-1, instead of using zinc N- (phenoxyacetyl) anthranilate, zinc N- (2-phenoxypropionyl) anthranilate was used. A thermosensitive recording paper was obtained by the same method except that the above was prepared.

(Example-7) The procedure of Example-1 was repeated, except that zinc N- (phenoxyacetyl) anthranilate was used instead of zinc N- (phenoxyacetyl) anthranilate to prepare a heat-sensitive coating solution. A thermal recording paper was obtained by the same method.

(Example-8) In the preparation of Example-1, 0.5 g of 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane dispersion was added. A heat-sensitive recording paper was obtained by the same method except that the heat-sensitive coating solution was prepared by changing the above.

(Example-9) In the preparation of Example-1, the amount of 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane dispersion added was changed to 1 g. A thermal recording paper was obtained by the same method except that the thermal coating solution was prepared.

Example 10 In the preparation of Example-1, the amount of 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane dispersion added was changed to 10 g. A thermal recording paper was obtained by the same method except that the thermal coating solution was prepared.

Comparative Example-1 Thermal recording paper was prepared in the same manner as in Example 1, except that bisphenol A was used instead of the zinc N- (phenoxyacetyl) anthranilate to prepare a thermal coating solution. Got

Comparative Example-2 A heat-sensitive coating solution was prepared by using 4- (4-isopropoxyphenylsulfonyl) phenol instead of using zinc N- (phenoxyacetyl) anthranilate in Example-1. A heat-sensitive recording paper was obtained by the same method as above.

(Comparative Example-3) 1, -1,3-of Example-1
Tris (2-methyl-4-hydroxy-5-tert-
A thermosensitive recording paper was obtained by the same method except that the thermosensitive coating liquid was prepared without adding the butylphenyl) butane dispersion liquid.

The heat-sensitive 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 25 mJ / printing energy with a Kyocera printing tester
The image was printed at mm ² and the color density was measured with a Macbeth densitometer.
The higher this value, the higher the sensitivity of the thermal recording paper. (2)
The chemical resistance test was conducted on the recording paper obtained by the above method on the white background portion and the color development portion of the ink. The degree of fog in the white background and the decoloring (discoloration) of the color-developed portion in the area where the 500 and Zebra highlighter pen (PEN-II yellow) was written was evaluated. The above results are shown in Table 1.

[0055]

[Table 1]

[0056]

As can be seen from the results of Table 1, the heat-sensitive recording material of the present invention has high sensitivity and does not cause fog coloration or decolorization of the color-developed portion due to chemicals, and has extremely excellent performance. I understand.

Claims (4)

[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 thermosensitive coloring layer having the following general formula (I) or (I):
A heat-sensitive recording material comprising an N-substituted anthranilic acid derivative represented by I) or a metal salt thereof, and a hindered phenol compound. [Chemical 1] [Chemical 2] (In the above formula, R ₁ is a hydrogen atom, an alkyl group or an aryl group, R ₂ is an alkyl group, a cycloalkyl group, an aryl group, an alkylamino group, an alkyloxy group, an aryloxy group or an arylamino group, and X is An oxygen atom or a sulfur atom, M is an n-valent metal atom, and n is an integer.) 2. The hindered phenol compound is added to the N-substituted anthranilic acid derivative or its metal salt in an amount of 5 to 2
The heat-sensitive recording material according to claim 1, which is used in an amount of 50% by weight. 3. The heat-sensitive recording according to claim 1, wherein the N-substituted anthranilic acid derivative or the metal salt thereof is N- (phenoxyacetyl) anthranilic acid or a zinc salt thereof. material. 4. The hindered phenol compound is 1,1,
3-tris (2-methyl-4-hydroxy-5-ter
t-butylphenyl) butane, 4,4′-butylidene-
Bis (6-tert-butyl-3-methylphenol)
The heat-sensitive recording material according to any one of claims 1 to 3, wherein