JPH04152185A - Sensitizer for heat sensitive recording and material for heat sensitive recording - Google Patents

Abstract

PURPOSE:To improve the coloring sensitivity, whiteness, light resistance, moisture resistance and plasticizer resistance by composing the title sensitizer of terephthalic acid dimethl ester and a specified compound. CONSTITUTION:The title sensitizer for heat sensitive recording consists of terephthalic acid dimethyl ester A, a compound B shown by a general formula 1, and a compound C shown by a general formula 2, as required. The title material for heat sensitive recording contains an electron donative colorless coloring agent and an electron acceptive development substance in a layer which formed on a supporting body, and is colored by heat, and contains this sensitizer in the layer which is formed on the supporting body. The weight ratio between terephthalic acid dimethyl ester A and the compound B is generally 25:75-80:20, and when A is less than 25, the heat sensitivity and plasticizer resistance as a heat sensitive recording paper is lowered. Also, when A exceeds 80, the heat sensitivity decreases. For this sensitizer, when the compound C is jointly used together with A and B, the sensitivity becomes sharper. The weight ratio between A+B and C is generally 95:0-50:50. When the compound C exceeds 50, the sensitivity decreases on the contrary lower, than the case of A and B only.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a heat-sensitive recording sensitizer and a heat-sensitive recording material. More specifically, the present invention relates to a sensitizer for heat-sensitive recording paper and a heat-sensitive recording material such as heat-sensitive recording paper.

[Prior Art] In recent years, there has been a significant demand for faster information processing, and various high-speed devices have been developed. Along with this, there is a demand for highly sensitive heat-sensitive recording materials. Heat-sensitive recording materials such as heat-sensitive recording paper develop color by melting an electron-donating colorless coloring agent and an electron-accepting color-developing substance contained in a layer formed on a support such as paper with heat and causing the two to associate. It is built using the principle of

Conventionally, as a sensitizer used in combination with the color forming agent and the color developing substance to improve sensitivity, for example, phthalic acid diphenyl ester (JP-A-57-11G [i90]) and benzyl biphenyls (JP-A-57-11G [I90]), Showa Go-82382 Publication
lil), a mixture of β,β'-bis-P-methoxyphenoxyethyl ether and 1,4-bisβ,β2phenoxyethoxybenzene (JP-A-64-3111i8
Publication No. 0), etc. have been proposed.

[Problems to be solved by the invention] However, the color development sensitivity of heat-sensitive recording materials using these sensitizers is still insufficient, and in particular higher fatty acid metals such as zinc stearate and calcium stearate are used to prevent sticking. A lubricant such as salt is usually added, but in this case color development sensitivity decreases. Further, there is a problem in that side effects due to increased sensitivity, ie, decreases in whiteness, chromaticity, light resistance, moisture resistance, and plasticizer resistance, cannot be avoided.

[Means for Solving the Problems] The present inventors have arrived at the present invention as a result of intensive studies to solve these problems. That is, the present invention relates to terephthalic acid dimethyl ester (A), which is a hydrocarbon group under the general formula), -OR group, -COOR group, +
COR group, halogen atom, NOs group or CN group; X is O atom or S atom; m and n are integers of 0 to 2. R+ and R2 are (thio)phenol residues which may have substituents, and Y represents 0 atom or S atom. A sensitizer; and a layer formed on the support contains at least an electron-donating colorless color former and an electron-accepting color developer, and in a heat-sensitive recording material that develops color by heat, the sensitizer is applied to the support. This is a heat-sensitive recording material characterized in that it is contained in a layer formed.

In the present invention, a residue means a group obtained by removing the 10H group or the -SH group from a certain compound.

In general formula (1), hydrocarbons having 6 or less carbon atoms for R include methyl, ethyl, n-propyl, isopropyl,
n-butyl, isobutyl, 5ec-butyl, tar
Straight chain or branched alkyl groups such as t-butyl, pentyl, hexyl; Straight chain or branched alkenyl groups and alkynyl groups such as vinyl, allyl, propenyl, impropenyl, 2-butenyl, ethynyl, 2-propynyl; phenyl, Carbocyclic groups such as cyclopentyl and cyclohexyl groups are preferably methyl, allyl, and phenyl.

In Z+ and Z*, the hydrocarbon group R having 6 or less carbon atoms can be the same hydrocarbon group as R in the above general formula (1). (The same goes for preferred compounds). In general formula (1), (Z+)- and (Z*) may be the same or different. fllh n is 0 to 2, preferably 0 or 1.

Specific examples of the compound (B) represented by the general formula (1) are shown in [1] to [9] below.

[1] Naphthacil (having a substituent) (thio) phenyl ether compound [2-corekylnaphthacil (having a substituent) (thio) phenyl ether compound [3] Phenylnaphthacil (having a substituent) ( thio) Phenyl ether compound [4-core alkoxynaphtacil (with a substituent) (thio) Phenyl ether compound [5-core aryloxinatutacil (with a substituent) (thio) Phenyl ether compound [6] Alkyl azyl naphtha sil (with a substituent) (thio) phenyl ether compound [7-cohalogenated naphthacil (with a substituent) (thio) phenyl ether compound [8-conitronaphthacil (with a substituent) (thio) phenyl ether Compound [9] Cyatnaphthacil (with a substituent) (thio) phenyl ether compound Among the compounds (B) exemplified above, preferred ones are natutacil (with any substituent) (thio) phenyl ether compound, alkylnaphthacil ( (thio)
Phenyl ether compound, alkoxynaphthasil CI!
Examples include (thio)phenyl ether compounds (having a substituent), nitronaphthacil (thio)phenyl ether compounds (having a substituent), and (thio)phenyl ether compounds (having a substituent).

Particularly preferred are Natsuta sylphenyl ether compounds,
Natsuta syl alkyl phenyl ether compound, Natsu syl aryl phenyl ether compound, Natsu syl alkoxy phenyl ether compound, Natsu syl alkylphenyl ether compound, Natsu syl phenyl ether compound, Natsu syl halogenated phenyl ether compound, naphta syl nitrophenyl ether compound, Natsuta Silcyanophenyl ether compound, alkylnaphthacylphenyl ether compound, alkylnaphthacyl alkylphenyl ether compound, alkylnaphthacyl arylphenyl ether compound, alkylnaphthadyl alkoxyphenyl ether compound, alkylnaphthacyl alkylacyl phenyl ether compound, alkylnaphthacyl halogen phenyl ether compound, alkylnaphthacyl nitrophenyl ether compound, alkylnaphthacyl cyanophenyl ether compound, alkoxynaphthacyl phenyl ether compound, alkoxynaphthacyl alkylphenyl ether compound, alkoxynaphthacyl arylphenyl ether compound, alkoxynaphthacyl alkoxyphenyl Examples thereof include ether compounds, alkoxynatsutacyl alkylacyl phenyl ether compounds, alkoxynatsutacyl halogenated phenyl ether compounds, alkoxynatsutacyl cyanophenyl ether compounds, and natsutacylphenyl ether compounds.

Two or more different types of compounds (B) may be used in combination.

In general formula (2), IIRI and R2 may be the same or different. R+ Y Ch- group and R2YC
The positions of the bonds between the H2-groups and the phenol ring are as follows: olf
Any of the fh and p positions may be used, with the p position being preferred.

Specific examples of the compound (C) represented by the general formula (2) are as shown in [1] and [2] below.

[Diethers of phenols which may have one substituent and P-xylene halide, etc. [2] Dieters of thiophenols which may have a substituent and xylene halide etc. Compounds exemplified above (C ), the preferred one is [
1], particularly preferred are diethers of phenol and P-xylene halide, diethers of methylphenol and P-xylene halide,
and a diether of methoxyphenol and P-xylene halide.

Two or more different types of compounds (C) may be used in combination.

In the present invention, the electron-donating colorless coloring agent (hereinafter abbreviated as coloring agent) is not particularly limited, and includes, for example, those used in known heat-sensitive or pressure-sensitive recording materials. Examples of the known coloring agents include triarylmethane-based, diphenylmethane-based, xanthine-based, phenothiazine-based, and spiropyran-based coloring agents.

Specific examples of triarylmethane coloring agents include 3.3
-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (crystal violet lactone, hereinafter abbreviated as CVL), 3,3-bis(p-dimethylaminophenyl)phthalide, 3-(p-dimethylaminophenyl)- 3-(1,2-dimethylindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)-3-(
2-methylindol-3-yl)phthalide, 3-(p
-dimethylaminophenyl)-3-(2-phenylindol-3-yl)phthalide, 3,3-bis(l,2-
dimethylindol-3-yl)-5-dimethylaminophthalide, 3,3-bis-(1,2-dimethylindol-3-yl)-6-dimethylaminophthalide, 3,3
-bis(9-ethylcarbazol-3-yl)-5-dimethylaminophthalide, 3,3-bis(2-phenylindol-3-yl)-5-dimethylaminophthalide,
Examples include 3-p-dimethylaminophenyl-3-(1-methylpyrrol-2-yl)-6-dimethylaminophthalide.

As a diphenylmethane color former, 4,4'-bis-
Dimethylaminobenzhydrin benzyl ether, N-
Examples include halophenyl leuco auramine and N-2.4.5-trichlorophenyl leuco auramine.

Examples of xanthine coloring agents include rhodamine-B-anilinolactam, rhodamine (p-nitroanilino)lactam, rhodamine (0-chloroanilino)lactam, and 3-
Diethylamino-7,8-benzofluorane, Rhodamine-B-(P-chloroanilinolactam), 2-anilino-3-methyl-6-dimethylaminofluorane, 2-
Anilino-3-methyl-〇-N-ethylaminofluorane, 2-anilino-3-methyl-8-N-methyl-N-
(isopropyl)aminofluorane, 2-anilino-3
-Methyl-6-N-methyl-N-cyclohexylaminofluorane, 2-anilino-3-methyl-6-ethylaminofluorane, 2-7nilino-3-methyl-6-sibutylaminofluorane, 2- Anilino-3-chloro-
6-Simethylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N-isoamylaminofluorane, 2-anilino-3-chloro-6-dinithylaminofluorane, 2-anilino-3 -chloro-Ei-N-methyl-N-ethylaminofluorane, 2-anilino-3-
Chloro-6-N-methyl-N-(isopropyl)aminofluorane, 2-anilino-3-chloro-6-N-methyl-N-cyclohexylaminofluorane, 2-anilino-3-chloroto N-methyl -N-pentylaminofluorane, 2-(P-methylanilino)-3-methyl-
6-Simethylaminofluorane, 2-(P-methylanilino)-3-methyl-Ei-N-methyl-N-ethylaminofluorane, 2-(P-methylanilino)-3-methyl-6-N-methyl -N-(isopropyl)aminofluorane, 2-(P-methylanilino)-3-methyl-
6-N-methyl-N-pentylaminofluorane, 2-
(P-methylanilino)-3-methyl-1i-N-methyl-N-cyclohexylaminofluorane, 2-(P-
methylanilino)-3-methyl-6-N-ethyl-N-
Pentylaminofluorane, 2-(P-methylanilino)-3-chloro-6-dimethylaminofluorane, 2-
(P-methylanilino)-3-chlorodiethylaminofluorane, 2-(P-methylanilino)-3-chloroto N-methyl-N-dithylaminofluorane, 2-
(P-methylanilino)-3-chloroto N-methyl-
N-(isopropyl)aminofluorane, 2-(P-methylanilino)-3-chloro-6-N-methyl-N-cyclohexylaminofluorane, 2-(P-methylanilino)-3-chloroto N-methyl -N-pentylaminofluorane, 2-(P-methylanilino)-3-chloro-11i-N-ethyl-N-pentylaminofluorane, 2-(P-methylanilino)3-chloro-G-N-
Methyl-N-furylmethylaminofluorane, 2-(P
-methylanilino)-3-ethyl-B-N-methyl-N
-furylmethylaminofluorane and the like.

Examples of the phenothiazine color former include benzoyl leucomethylene blue, p-nitrobenzoyl leucomethylene blue, and the like.

As a spiropyran coloring agent, 3-methyl-spiro-
dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3,3'-cyclospirodinaphthopyran, 3-
Benzyl°-spirodinaphthopyran, 3-methyl-naphtho-(3-methoxy-benzo)-spiropyran, 3-
Examples include propylose spirodibenzodipyran.

As an indolylphthalide coloring agent, 3,3-bis(
1-Ethyl-2-methylindol-3-yl)phthalide, 3,3-bis(l-octyl-2-methylindol-3-yl)phthalide, 3-(2-ethoxy-4-diethylaminophenyl)-3 -(1-ethyl-2-methylindol-3-yl)phthalide, 3-(2-ethoxy-4-dibutylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)phthalide, 3 −(
2-amyloxy-4-diethylaminophenyl)-3
-(1-ethyl-2-methylindol-3-yl)phthalide, 3-(2-ethoxy-4-diethylaminophenyl)-3-(1-octyl-2-methylindole-
Examples include 3-yl) phthalide.

Examples of pyridine-based coloring agents include 3-(2-ethoxy-4-diethylaminophenyl)-3-(1-octyl-2-methylindol-3-yl)-7-azaphthalide, 3-
(2ethoxy-4-diethylaminophenyl)-3-(
1-ethyl-2-methylindol-3-yl)-4-
Examples thereof include azaphthalide, 3-(2-hexyloxy-4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)4-azaphthalide, and the like.

Examples of fluorene color formers include 3',[i'-bisdiethylamino-5-diethylaminospiro(inbenzofuran-1,9'-fluorene)-3'-one, 3',Ei
'-Bisdiethylamino-7-diethylamino-2-methylspiro(l,3-benzoxazine-4,9'-fluorene) -3'-one 31. [i+-bisdiethylamino-7-diethylaminospiro(2-hydro-1
,3-benzoxazine-4,3'-fluorene)-2
- Examples include on.

These color formers may be used alone or in combination of two or more.

On the other hand, as the electron-accepting color-developing substance (hereinafter abbreviated as color-developing agent), various electron-accepting color-developing substances can be used that react with the color former when heated to develop color. Examples of such color developers include phenolic substances, organic or inorganic acidic substances, and salts thereof.

Specific examples include "Paper and Pulp Technology Times, Chic Time Co., Ltd., Vol. 30, No. 6 to Vol. 31, No. 3"
``Color developer for thermal recording paper (1) - (complete), written by Takashi Shiga'' serialized in ``Color developer for thermal recording paper (1) - (complete), written by Takashi Shiga'' and ``Color developer for thermal recording paper (1)'' published in ``Volume 32, No. 4 to Volume 32, No. ) ~ (complete), written by Takashi Shiga”
These include those listed in . Specifically, the following can be mentioned.

(1) Bisphenol color developer (1-1) Non-sulfur-containing bisphenol color developer 2-(4
-hydroxyphenyl)propane, 2-(3'-hydroxyphenyl)propane, tetrabromobisphenol A14,4'-isopropylidenediphenol, 4,4
Bisphenol A related compounds such as '-butylidenebis (2-t-butyl-5-methylphenol), 4,4
1-methylenebis(2-cyclohexyl-5-methylphenol), 4,4'-isopropylidenebis(2-cyclohexyl-5-methylphenol), 4,4'-butylidenebis(2-cyclohexyl-5-methylphenol) ), 4,4'-cyclohexylidenebis(2-cyclohexyl-5-methylphenol), 3,3-bis(
Ethyl 3-cyclohexyl-4-hydroxy-5-methylphenol)butanoate, 4-[1,1-bis[4
-hydroxyphenyl)ethylcopyphenyl, 2-[1
, 1-bis(4-hydroxyphenyl)ethylcopiphenyl, l-phenyl-1,1-bis(4-hydroxyphenyl)butane, 1,1-bis(p-hydroxyphenyl)cyclohexane, 4,4'-butylidenebis (2-
Bisphenol A related compounds such as cyclohexyl 5-methylphenol), methyl-phenyl-methylidene bisphenol, l,1-bis(4-hydroxyphenyl)acetic acid, 2,2-bis(4-hydroxyphenyl)propionic acid, bisphenol (4-hydroxyphenyl)acetic acid methyl ester, bis(4-hydroxyphenyl)acetic acid M-n
-butyl, bis(4-hydroxyphenyl)propargyl acetate, bis(4-hydroxyphenyl)cinnamyl acetate, bis(4-hydroxyphenyl)benzyl acetate, bis(4-hydroxyphenyl)phenyl acetate, bis(4-hydroxyphenyl)acetate,
Hydroxyphenyl) phenethyl acetate, bis(4-hydroxyphenyl) ff[-β-(4'-ethoxyphenoxy)ethyl, 2,2-bis(4-hydroxyphenyl)acetate-3-phenoxypropyl, 2,2-bis (4-
hydroxyphenyl)valerate-β-(42-methylphenoxy)ethyl, bis(4-hydroxyphenyl)stearamide, 1,3-bis(4-hydroxyphenyl)propane, 2,4-bis(4-hydroxyphenyl) )-4-Methylpentane, l,3-di[2.(4-hydroxyphenyl)-2-propyl]benzene, 1.3-
Di[2-(3,5-dimethyl-4-hydroxyphenyl)-2-propylcobenzene, bisphenol 1.1
-Bis(hydroxyphenyl) acid compounds (1-2) such as bis(hydroxyphenyl)-1-phenylethane
Sulfur-containing bisphenol color developer 4.4' dihydroxyphenyl diphenyl sulfone, 2.4' dihydroxyphenyl diphenyl sulfone, bis-(3-allyl-4-
hydroxyphenyl)sulfone, bis-(3-allyl-
4-hydroxyphenyl) sulfone, 3-3'-sulfonylbis(4-hydroxybenzoic acid methyl ester),
1. Bisphenolsulfone derivatives such as 3-bis(p-hydroxyanilinosulfonyl)benzene; 4-hydroxy-4'-benzyloxydiphenylsulfone, 4-
Monoethers of bisphenolsulfones such as hydroxy-41-isopropoxydiphenylsulfone: bis(3,S-dimethyl-4-hydroxyphenyl)sulfide, bis(2-methyl-5-isopropyl-4-hydroxyphenyl)sulfide, 4, 4'-thiobis(l
1i-ter-butyl-3-methylphenol), 1.
5-di(4-hydroxyphenylthio)-3-oxypentane, l,8-di(4-hydroxythio)-3,[i
-dioxaoctane, 1,3-di(4-hydroxyphenylthio)acetone, 1,7-di(4-hydroxyphenylthio)-3,5-dione, 1,2-di(4-hydroxyphenylthio) Phenylethane, Wataru, 2-di(4-
hydroxyphenylthio)-1-(4-chlorophenyl)ethane, methyl 4-hydroxyphenylthio-4-hydroxyphenyl)acetate, methyl bis(4-hydroxyphenylthio)acetate, 4-benzyloxyphenyl-4
- Bisphenol sulfide such as hydroxyphenyl sulfide (2) Hydroxyarylcarboxylic acid color developer (2-1
) Hydroxybenzoic acid color developer p-hydroxybenzoic acid, hydroxybenzoic acid, salicylic acid, methyl p-hydroxybenzoate, benzyl p-hydroxybenzoate,
p-hydroxybenzoic acid-β-p-methoxyphenoxyethyl, p-hydroxybenzoic acid-β-p-phenoxyethyl, p-hydroxybenzoic acid-β-p-methoxyphenoxyethyl, p-hydroxybenzoic acid-2-(o -Hydroxybenzoic acid and p-hydroxybenzoic acid esters such as -hydroxyphenylthio)ethyl; 2,4-dihydroxybenzoic acid octadecyl, 2,4-dihydroxybenzoic acid-β-p-ethoxyphenoxyethyl, 2,
β-methallyloxyethyl 4-dihydroxybenzoate, β-ethyloxyethyl 2,4-dihydroquinebenzoate, 2,4-dihydroxy-β-phenylthioethyl, ■, 4-cyclohexane dimethanol-rubis-( p-
Hydroxybenzoic acid derivatives (2-2) such as hydroxybenzoic acid ester, l,4-ethylene glycol-bis-(p-hydroxybenzoic acid) ester, salicylic acid color developer, salicylic acid metal salt (Z no M gt Cal
A I ), 4-tetradecyloxysalicylic acid, 4
-β-p-)lyoxyethoxysalicylic acid, 3,5-di(α-methylbenzyl)salicylic acid, 3,5-di(
α,α-dimethylbenzyl)salicylic acid, 3,5-di-ter-butylsalicylic acid, 3-isopropenyl-5-
tar-butylsalicylic acid, 3-vinyl-5-cyclohexanoic acid, 3vinyl-5-benzylsalicylic acid, 5-myristoylsalicylic acid, 5-phenylacetylsalicylic acid, methylphenoxyacetylsalicylic acid, 4-myristoylaminosalicylic acid, 4-phenylacetylaminosalicylic acid , 2゜2-bis(3-carboxy-4-hydroxyphenyl)furopane, l,4-bis(3-carboxy-4-hydroxycumyl)benzene, bis(2-hydroxy-3-carboxy-5-α- salicylic acid derivatives such as (phenethylphenyl) methane (2-3) Other hydroxyarylcarboxylic acid color developers dimethyl 4-hydroxyphthalate, zinc 3,4,5.6-tetrachlorophthalate-mono-2-hydroxyethyl Salt, 3, 4, 5. Phthalic acid derivatives such as the zinc salt of G-tetrachlorophthalate-mono-3-hydroxy-2,2-dimethylpropyl, P-chlorobenzyl gallate,
Gallic acid derivatives such as benzyl gallate and p-vinylbenzyl gallate: l-hydroxy-4-benzyloxy-2-naphthoic acid, l-acyloxy-4-benzyloxy-2-naphthoic acid, 2-acyloxy-4 -benzyloxy-1-naphthoic acid, Z nl of these acids
Naphthoic acid derivatives such as polyvalent metal salts such as Mg (2-4) Other carboxylic acid color developers 0-methyl fumarate, p-methyl fumarate, 0-ethyl fumarate,
p-benzyl fumarate, 0-naphthylmethyl fumarate,
Zinc indole-2-carboxylate, calcium indole-2-carboxylate, zinc l-methylindole-2-carboxylate, zinc p-nitrobenzoate, p-nitrobenzoic acid, L-ascorbic acid, etc. (3) Sulfone Color developer methyl 4-hydroxybenzenesulfonate, ethyl 4-hydroxy-3-methyl-5-bromobenzenesulfonate, ethyl 4-hydroxy-3,5-dibromobenzenesulfonate, 4-hydroxy-4'-methyl Diphenylsulfone, 3',4') dimethylene-4-hydroxydiphenylsulfone, 2-(4-hydroxybenzenesulfonyl)naphthalene, 1-(4-hydroxybenzenesulfonyl)naphthalene, 3-allyl-4-hydroxy-
4'-methyldiphenylsulfone, 3-allyl-4-hydroxy-4'-methoxydiphenylsulfone, 3-allyl-4-hydroxy-4'-(2-phenoxyethoxy)diphenylsulfone, 3,4-dihydroxyphenyl-p -Tolylsulfone, 2,2'-bis(4-hydroxybenzenesulfonyl)ethyl ether, 4-hydroxy-41-isopropoxydiphenylsulfone, 4-
Hydroxy-4'-chlorodiphenylsulfone, 3,5
- Sulfonic color developer such as diβ-phenoxyethoxycarbonylbenzenesulfonic acid, 2-β-naphthoxyethoxynaphthalene-6sulfonic acid; N-benzenesulfonyl 1-7 minophenol, N-(α-naphthalenesulfonyl)- shoulder-aminophenol, 1,3-bis(p-
Hydroxyanilinosulfonylbenzene, N-(2-phenoxyethyl)-4-hydroxybenzenesulfonamide, N-(3-phenoxypropyl)-4-hydroxybenzenesulfonamide, N-(phenylsulfonyl)-p-toluenesulfonamide , n-butyl-N-(o
-carboxyphenylsulfonyl) p-aminobenzony), N-(dimethylsulfamoyl)-p-toluenesulfonamide, N,N'-diphenylsulfonamide; α-naphthalenesulfonyl chloride, p-phenyl Sulfonyl chloride compounds such as benzenesulfonyl chloride These color developers may be used alone or in combination of two or more.

In the sensitizer of the present invention, the weight ratio of dimethyl terephthalate (A) to the compound (B) represented by general formula (1) is usually 25:5 to 80:20, preferably 30.
: 20-75:25, particularly preferably 35:ei5
~70:30. If (A) is less than 25, the sensitivity and plasticizer resistance for thermal recording paper will decrease. Moreover, when (A) exceeds 80, the sensitivity decreases.

In the sensitizer of the present invention, (A) and (B) are represented by the general formula (
When compound (C) shown in 2) is used in combination, the sensitivity becomes even sharper. The weight ratio of (A) + (B) and CC') is usually 95:0 to 50:50, preferably 90:
10-55: 45. Compound (C) is 50
On the other hand, if the value exceeds 1, the sensitivity will be lower than in the case of only (A) and (B).

The sensitizer consisting of (A), (B) and, if necessary, (C) of the present invention is usually used after each component is ground into fine powder and mixed.

In the heat-sensitive recording material of the present invention, the amount of the sensitizer of the present invention used is usually 1 to 200 parts by weight, preferably 3 to 0 parts by weight, particularly preferably 10 parts by weight, per 100 parts by weight of the color developer.
~70 parts by weight. If the amount of the sensitizer used is less than 1 part by weight, the effect of improving sensitivity in thermal recording will be reduced, and if it exceeds 200 parts by weight, the effect of improving sensitivity will be saturated and uneconomical.

The ratio of the color former to the color developer is usually 5 to 100 parts by weight, preferably 10 to 70 parts by weight, particularly preferably 20 to 50 parts by weight per 100 parts by weight of the color former. . If the amount of the color developer used is less than 5 parts by weight, the color density will decrease, and if it exceeds 100 parts by weight, the color density will reach an equilibrium, making it uneconomical to use any more.

In the present invention, the support is preferably paper, such as paper, synthetic paper, or synthetic resin film.

Next, a method for producing the heat-sensitive recording material of the present invention will be illustrated.

A suspension solution containing each of a sensitizer, a color former, and a color developer is prepared. Subsequently, each suspension solution alone or a suspension solution mixture consisting of a combination determined according to various coating methods is used as a coating solution and coated on a support to produce a heat-sensitive recording material.

¥ each! To give an example of a method for producing a Nagoya solution, a sensitizer and a binder, a color former and a binder, and a color developer and a binder are mixed in water and optionally a surfactant (2-ethylhexyl sulfosuccinate soda salt, naphthalene sulfonic acid). 10μ or less using a grinder such as a ball mill, atrider, or sand grinder with a soda salt formalin condensate, etc.
Preferably, each suspension solution is obtained by grinding and dispersing the particles into particles of 3 μm or less.

Examples of the binder include polyvinyl alcohol,
Starch and its derivatives, cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose; sodium polyacrylate, polyvinylpyrrolidone, acrylic amide/acrylic ester copolymer,
Acrylic acid amide/acrylic ester/methacrylic acid terpolymer, styrene/maleic anhydride copolymer alkali salt, inbutylene/maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, casein, etc. In addition to water-soluble polymers, polyvinyl acetate, polyurethane, styrene/butadiene copolymer, polyacrylic acid, polyacrylic ester, vinyl chloride/
Latex such as vinyl acetate copolymer, polybutyl methacrylate, ethylene/vinyl acetate copolymer, styrene/butadiene/acrylic copolymer, etc. can be used.

As shown in Table 1 below, the coating solution may be a mixture of three suspension solutions, a mixture of two solutions, or a single solution, depending on the various coating methods.

Table 1 Note) Mark 0 indicates the suspension solution constituting each of coating solutions a to g.

Further, each coating liquid may contain, if necessary, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as fillers, thermofusible substances, lubricants, and the like. Examples of fillers include calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay kaolin, talc, and surface-treated inorganic fine powders such as calcium carbonate and silica, as well as urea. Examples include organic fine powders such as formalin resin, styrene/methacrylic acid copolymer, and polystyrene resin. Examples of thermofusible substances include stearic acid amide, stearic acid methylenebisamide, oleic acid amide, higher fatty acid amide such as coconut fatty acid amide, bisamide such as ethylene bisstearylamide, dodecyl-N'-lauryl urea, and tostearyl-N' -Urea-based compounds such as tocosyl urea, other known thermofusible substances, etc.
Examples include those having a melting point of 00°C.

As lubricants, zinc stearate, calcium stearate, magnesium stearate, lead stearate,
Examples include higher fatty acid metal salts such as cadmium stearate, barium stearate, and aluminum stearate, as well as waxes such as stearic acid, polyethylene, carnauba wax, beeswax, and paraffin wax.

The coating solution can be applied to the support using an air knife coater, a blend coater, etc.
Coating is done by a method such as a roll coater/wifeless method. Further, as a method for forming the heat-sensitive recording layer, for example, the heat-sensitive recording layer may be formed by the following methods (I) to (■) in which the combinations selected from coating liquids a to g shown in Table 1 are changed. can.

(I) Coating the coating liquid (a) onto the support. FIG. 1 shows the heat-sensitive recording material obtained. In FIG. 1, 1 is a support, and 2 is a layer containing a mixture of a sensitizer, a color former, and a color developer.

(II) Coating liquid (d) is applied onto the support, and coating liquid (e) is further applied on top of the coating liquid (d). FIG. 2 shows the heat-sensitive recording material obtained. In FIG. 2, 5 is a layer containing a mixture of a color forming agent and a color developer, and 6 is a layer containing a sensitizer.

(III) Coating liquid (e) is applied onto the support, and coating liquid (d) is further applied on top of the coating liquid (e). FIG. 3 shows the heat-sensitive recording material obtained. In FIG. 3, 6 is a layer of a sensitizer, and 5 is a layer containing a mixture of a color former and a color developer.

(IV) Coating solution (g), coating solution (e), and coating solution (f) are coated on the support in a layered manner. FIG. 4 shows the heat-sensitive recording material obtained. In FIG. 4, 8 is a color developer layer, 6 is a sensitizer layer, and 7 is a color former layer.

(V) Coating liquid (f), coating liquid (e), and coating liquid (g) are sequentially layered on the support. The obtained thermosensitive recording material is shown in FIG. In FIG. 5, 6 is a sensitizer layer, 7 is a color former layer, and 8 is a color developer layer.

(VI) Coating liquid (b) is coated on the support, and coating liquid (c) is further coated on top of the coating liquid (b). The obtained thermosensitive recording material is shown in FIG. In FIG. 6, 3 is a layer containing a mixture of a sensitizer and a color former, and 4 is a layer containing a mixture of a sensitizer and a color developer.

(■) Coating liquid (C) is applied onto the support, and coating liquid (b) is further applied on top of the coating liquid (C). The obtained thermosensitive recording material is shown in FIG. In FIG. 7, 4 is a layer in which a sensitizer and a color developer are mixed, and 3 is a layer in which a sensitizer and a color former are mixed.

Among these, preferred methods for forming a heat-sensitive recording layer (n) (
VI) and (■).

The coating thickness of each layer is determined depending on the form of the heat-sensitive recording material and other conditions. The coating amount is not particularly limited, but is usually 0.5 to 20 g/lI2, preferably 1 to 15 g/lI2, particularly preferably 3 to 10 g/lI2 in terms of dry weight.
g/intestine 2.

[Examples] The present invention will be further described below with reference to Examples, but the present invention is not limited thereto. Parts and percentages in the examples are by weight. Further, the test methods in the examples are shown below.

(Test method) (1) Color development l) Dynamic color development test The produced thermal recording paper was tested for the relationship between operating time (pulse width) and color density using an MSI type thermal head printing device. 0.1 to 1.0 m5ec, voltage 22v0 Color density was determined by measuring reflection density using a Macbeth densitometer (manufactured by Macbeth). The larger the value, the higher the color density.

2) Static color development test The prepared thermal recording paper was heated using a thermal gradient heat sealer at a temperature range of 70'C to 100'C and a printing pressure of 2 kg/cm.
The color was developed under the conditions of 2 seconds of pressure bonding time and the color density was measured. The concentration meter is the same as 1).

(2) Whiteness (background fog) Hunter white discoloration before coloring of thermal recording paper, B value is Mu
ltl 5pectro Co1our Meter
Measurement was performed using H2O-2 type. The larger the value, the higher the degree of whiteness.

(3) Light resistance The colored image area was irradiated for 72 hours at 80° C. using a fade meter, and the color density of the irradiated area was measured.

The densitometer is the same as l).

(4) Humidity Resistance Test The image area colored in the color development test was left in a constant temperature and humidity chamber at 45° C. and 90% RH for 24 hours, and then the color density of the image area was measured. The concentration meter is the same as 1).

(5) Plasticizer Resistance Test A plastic eraser was placed on the image area that had been colored in advance in the color development test, and after being left for 24 hours, the color density of the image area was measured. The densitometer is the same as l).

Examples 1 to 6, Comparative Examples 1 to 7 Production Examples 1 to 6 and Comparative Production Examples 1 to 7 Each of the compounds shown in Table-2 was finely ground, and
) to obtain sensitizers ① to ② of the present invention.

Sensitizers (1) to (0) of Comparative Production Examples were each obtained by finely pulverizing each compound shown in Table 2 (2). Sensitizer of comparative production example @,
[Phase] was obtained by mixing and melting the compounds shown in Table 2 (2) at 150°C, cooling and finely pulverizing the mixture.

Table 2 (1) Table 2 (2) Examples 1 to 6, Comparative Examples 1 to 7 In Tables 3 to 5, A1 BB and CC liquids were respectively ground and dispersed in a ball mill for 24 hours, then 6 Display the liquid.
The combinations shown in 7 were sufficiently mixed to prepare coating liquids of Examples 1 to 6. This coating liquid was applied onto high-quality paper (basis weight 50 g/shoulder 2) with a doctor blade so that the dry solid content was 6 g/■2, and after drying, Created the material.

In addition, the same procedure as above was carried out except that the conventional sensitizer suspension solutions shown in Table 6 were used instead of the AA solution, and the combinations shown in Table 8 were used instead of the combinations shown in Table 7. Coating liquids and heat-sensitive recording materials of Comparative Examples 1 to 7 shown in Table 8 were prepared. Obtained Examples 1 to 6 and Comparative Examples 1 to 7
Tables 9 to 1 show the results of measuring each performance of the heat-sensitive recording material.
Shown in 1.

Table-3 note) (14): calcium carbonate (15): hydroxyethylcellulose (10% aqueous solution) Table-4 Table-5 Table-6 Table-7 [Sensitizer-containing coating liquid of the present invention] (unit: Department) table [Conventional sensitizer-containing coating liquid] (unit: Department) Table-9 Dynamic color development test Table-1 Static color test Table-1 Table-9~1 As is clear from 1, the heat sensitivity of the present invention Color development of recording paper, lightfastness, Moisture resistance and plasticizer resistance Both properties were superior to conventional thermal recording paper.

In particular, in Comparative Examples 1 and 2, the sensitizer ■ used had a p of 142°C, and the sensitizer ■ had a high p of 145°C (both conventional sensitizers), resulting in extremely poor sensitivity. .

Production Example 7 In the same manner as in Production Examples 1 to 6, the compounds shown in Table 12 were each finely ground and mixed to obtain a sensitizer [phase] of the present invention.

Table 12 Examples 7 to 9, Comparative Example 8 The following DD and EE solutions were ground and dispersed in a ball mill for 24 hours to obtain a suspension solution. Spread this solution on high-quality paper (basis weight Bo
g/■ 2) Methods (I), (VI) and (■), i.e. CI), are a mixture of DD liquid and EE liquid (1 part 1 weight ratio) on paper with a dry solid content of 8 g/2). It was applied with a doctor blade and dried. (VI) is coating liquid D on paper.
Liquid D was applied using a doctor blade to a dry solid content of 4E/at, and then liquid EE was similarly applied onto this layer and dried. (■) is the opposite of (Vl), and the husband ζE
Liquid E was applied, and then liquid DD was applied. The coating amount is (V
The same as I).

CDD liquid: mixed suspension solution of sensitizer and color former] Sensitizer @
10 part 2-anilino-3
-Methyl-6-sibutylaminofluorane
15 parts zinc stearate
5 parts calcium carbonate
5 parts polyvinyl alcohol (10% aqueous solution) 35 parts water
30 parts CEE solution: mixed suspension of sensitizer and color developer Co-sensitizer [phase] 10 parts Bisphenol A 20 parts Zinc stearate 5 parts 1.5-di(4-
Hydroxyphenylthio)-3-oxapentane
10 parts calcium carbonate
5 parts polyvinyl alcohol (
10% aqueous solution) 35 parts water
15 parts Coating method (I), (
The heat-sensitive recording materials prepared in VI) and (■) were designated as Examples 7.8 and 9, respectively.

In addition, as Comparative Example 8, the sensitizer [phase] of the DD and EE liquids was
A heat-sensitive recording material (Comparative Example 8) was prepared by coating with the coating method (I) using P-benzylbiphenyl instead. Next, the results of measuring the performance of the heat-sensitive recording materials of Examples 7 to 9 and Comparative Example 8 are shown in Tables 13 to 15.

Table - Dynamic Color Development Test Table - Static Color Development Test Table - As is clear from Tables 13 to 15, the color development, light fastness, moisture resistance, and plasticizer resistance of the heat-sensitive recording material of the present invention are higher than those of conventional heat-sensitive recording materials. It was superior to recording materials.

Furthermore, the heat-sensitive recording material (Example 8) produced by the coating method (VI) was the most excellent.

[Effects of the Invention] The heat-sensitive recording material of the present invention containing the sensitizer of the present invention has the following effects:
Compared to conventional products, even when a lubricant such as a higher fatty acid metal salt is added, the color development sensitivity is significantly higher (and the whiteness (background fog) is excellent).

Additionally, the image area provides high quality performance such as light fastness, moisture resistance and plasticizer resistance.

Because of these effects, the sensitizer and heat-sensitive recording material of the present invention are useful for various recording materials such as facsimiles and POS labels.

[Brief explanation of drawings]

1 to 7 are schematic diagrams (cross-sectional views) of the heat-sensitive recording material of the present invention. 1...Support, 2...A layer containing a mixture of a sensitizer, a color former and a color developer, 3...A layer containing a mixture of a sensitizer and a color former, 4...A layer containing a mixture of a sensitizer and a color former. A mixed layer of colorants,
5... Layer containing a mixture of color former and color developer 6... Layer of sensitizer, 7... Layer of color former, 8... Layer of color developer Fig. 1 Fig. 2

Claims (1)

[Claims] 1. Terephthalic acid dimethyl ester (A), general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) [In the formula, Z_1 or Z_2 is a -R group (R is a carbon number of 6 or less) hydrocarbon group), -OR group, -COOR group, -
COR group, halogen atom, NO_2 group or CN group;
is an O atom or an S atom; m and n are integers from 0 to 2], and if necessary, there is a general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (2) [In the formula, R_1 and R_2 is a (thio)phenol residue which may have a substituent, and Y represents an O atom or an S atom. agent. 2. The sensitizer according to claim 1, wherein the content of (A) is 25% by weight or more. 3. A heat-sensitive recording material that contains at least an electron-donating colorless color former and an electron-accepting color developer in the layer formed on the support, and that develops color when heated, as claimed in claim 1 or 2.
A heat-sensitive recording material, characterized in that a layer formed on a support contains the sensitizer according to any one of the above. 4. The layer formed on the support is a laminated layer of a layer in which the electron-donating colorless color former and the electron-accepting color developer are mixed and a layer of the sensitizer. Heat-sensitive recording material. 5. The layer formed on the support is a layer in which the sensitizer and the electron-donating colorless coloring agent are mixed, and a layer in which the sensitizer and the electron-accepting color developer are mixed. The heat-sensitive recording material according to claim 3, which is a layer. 6. The layer formed on the support is a laminated layer of a layer in which the sensitizer and the electron-accepting color developer are mixed and a layer in which the sensitizer and the electron-donating colorless color former are mixed. The heat-sensitive recording material according to claim 3.