JPH07309804A - Heat-sensitive recording material and metal salt of benzoic acid derivative - Google Patents

Abstract

PURPOSE:To obtain the benzoic acid derivative or its metal salt giving heat- sensitive recording materials remarkably improved in the storage stability of colored picture images. CONSTITUTION:In the heat-sensitive recording. material containing an electron- donating coloring compound and an electron-receiving compound, at least one of a benzoic acid derivative of formula I (X1-X4 are H, alkyl, alkoxy, halogen, nitro; Y1, Y2 are H, alkyl, alkoxy, halogen; R1 is aryloxy, alkylthio, alkenylthio, arylthio) and its metal salt is contained as the electron-donating compound. The compound of formula I is especially preferably a compound of formula II, e.g. 2-(4'-phenyloxybenzoyl)benzoate. The metal salt of the compound of formula I includes an alkali metal salt, but is preferably a water-slightly soluble or insoluble polyvalent metal salt, especially a divalent metal salt.

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 having improved storage stability of a color image. Furthermore, the present invention relates to a metal salt of a benzoic acid derivative useful as an electron-accepting compound for heat-sensitive recording materials, an additive for polymer materials and the like.

[0002]

2. Description of the Related Art Conventionally, a heat-sensitive recording material utilizing a color reaction between an electron-donating color-forming compound and an electron-accepting compound (developing agent) is well known (for example, Japanese Patent Publication No. 43-4).
160, JP-B-45-14039). The heat-sensitive recording material is relatively inexpensive and has a merit that the recording device is compact and maintenance-free, and thus is widely used in the fields of facsimiles, recorders, printers and the like.

Phenolic compounds are widely used as electron-accepting compounds. Among them, 2,2-bis (4'-hydroxyphenyl) propane ["bisphenol A"] is used.
Is widely used because it is inexpensive and easily available, but the heat-sensitive recording material using bisphenol A as an electron-accepting compound has a problem that storage stability of a color image is poor.

As a method for improving the storage stability of a color image, for example, it is known that a metal salt of a benzoic acid derivative having a specific structure is useful as an electron-accepting compound or a color image stabilizer (for example, a special method). Japanese Examined Patent Publication No. 2-26874, Japanese Examined Patent Publication No. 2-39994, and Japanese Examined Publication No. 4-171
No. 75, etc.). However, the heat-sensitive recording material using the metal salt of these benzoic acid derivatives, in terms of color development performance or storage stability (moisture and heat resistance of uncolored portion and color image, oil resistance, writing instrument resistance, etc.), practically, It is hard to say that it has sufficient performance.

At present, there is a strong demand for a heat-sensitive recording material having excellent storage stability which overcomes the above-mentioned problems.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material which is remarkably improved in the storage stability of a color image. Furthermore, it is to provide a metal salt of a benzoic acid derivative which is useful as an electron-accepting compound for a heat-sensitive recording material.

[0007]

The inventors of the present invention have arrived at the present invention as a result of earnest studies on a heat-sensitive recording material in order to meet the above demands.

That is, the present invention provides a thermosensitive recording material containing an electron-donating color-forming compound and an electron-accepting compound, wherein the electron-accepting compound is a benzoic acid derivative represented by the general formula (1) or a derivative thereof. A heat-sensitive recording material containing at least one metal salt,

[0009]

[Chemical 3] (In the formula, X ₁ , X ₂ , X ₃ and X ₄ represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a nitro group, and Y ₁ and Y ₂ represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen. Represents an atom, and R ₁ represents an aryloxy group, an alkylthio group, an alkenylthio group or an arylthio group. Furthermore, a benzoic acid represented by the general formula (1), which is useful as an electron-accepting compound for a heat-sensitive recording material. It is a metal salt of a derivative.

In the benzoic acid derivative represented by the general formula (1), X ₁ , X ₂ , X ₃ and X ₄ represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a nitro group, preferably hydrogen. An atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a chlorine atom, a bromine atom or a nitro group, and more preferably a hydrogen atom or a carbon number. It is an alkyl group having 1 to 4, a cyclohexyl group, an alkoxy group having 1 to 4 carbon atoms or a chlorine atom, and a hydrogen atom is particularly preferable.

In the benzoic acid derivative represented by the general formula (1), Y ₁ and Y ₂ represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Group, a cycloalkyl group having 5 to 8 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a chlorine atom or a bromine atom, and more preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a cyclohexyl group, or a carbon number. 1 to
4 is an alkoxy group or a chlorine atom, and a hydrogen atom is particularly preferable.

In the general formula (1), R ₁ is an aryloxy group which may have a substituent, an alkylthio group which may have a substituent, or an alkenylthio group which may have a substituent. Alternatively, it represents an arylthio group which may have a substituent.

The alkylthio group or alkenylthio group of R ₁ may have a substituent, and for example, has 1 to 1 carbon atoms.
An alkoxy group having 20 carbon atoms, an alkoxyalkyloxy group having 2 to 20 carbon atoms, an alkenyloxy group having 2 to 20 carbon atoms,
Alkylthio group having 1 to 20 carbon atoms, alkoxyalkylthio group having 2 to 20 carbon atoms, alkylthioalkylthio group having 2 to 20 carbon atoms, alkenylthio group having 2 to 20 carbon atoms, cyclic alkyl which may contain a hetero atom Base,
It may be mono-substituted or poly-substituted with a substituent such as a halogen atom.

Further, the aryl group in the aryloxy group or the arylthio group of R ₁ may have a substituent, for example, an alkyl group having 1 to 20 carbon atoms or 2 to 2 carbon atoms.
20 alkenyl groups, C1-C20 alkoxy groups,
It may be mono-substituted or poly-substituted with a substituent such as a halogen atom, a nitro group, a formyl group, a hydroxyl group and a cyano group.

Preferably, R ₁ is an aryloxy group having 6 to 20 carbon atoms which may have a substituent, an alkylthio group having 1 to 20 carbon atoms which may have a substituent,
Alkenylthio group having 2 to 24 carbon atoms which may have a substituent, and 6 to 20 carbon atoms which may have a substituent
And more preferably an aryloxy group having 6 to 12 carbon atoms, which may have a substituent,
Alkylthio group having a total carbon number of 1 to 10 which may have a substituent, alkenylthio group having a total carbon number of 2 to 12 which may have a substituent, and total carbon which may have a substituent. An arylthio group of the formulas 6 to 12, and more preferably
Phenyloxy group having a total carbon number of 6 to 10 which may have a substituent, alkylthio group having a total carbon number of 1 to 8 which may have a substituent, total carbon which may have a substituent Number 2
An alkenylthio group having 10 to 10 and an arylthio group having 6 to 10 carbon atoms which may have a substituent, particularly a phenyloxy group and 1 to 1 carbon atoms which may have a substituent.
An alkylthio group having 8 carbon atoms, an alkenylthio group having 1 to 8 carbon atoms which may have a substituent, or a phenylthio group is preferable.

Specific examples of R ₁ include, for example, phenyloxy group, 4-methylphenyloxy group, 4-ethylphenyloxy group, 4-n-propylphenyloxy group, 4-isopropylphenyloxy group, 4-n -Butylphenyloxy group, 4-sec-butylphenyloxy group, 4-tert-butylphenyloxy group, 4-n-pentylphenyloxy group, 4-isopentylphenyloxy group, 4-n-hexylphenyloxy group, 4-n-heptylphenyloxy group, 4-n-octylphenyloxy group, 4-tert-octylphenyloxy group, 4-n-decylphenyloxy group, 4-n-dodecylphenyloxy group, 4-cyclopentylphenyloxy group Group, 4-cyclohexylphenyloxy group, 4-allylphenyloxy group,

4-methoxyphenyloxy group, 4-isopropoxyphenyloxy group, 4-n-butoxyphenyloxy group, 4-isobutoxyphenyloxy group, 4-n-pentyloxyphenyloxy group, 4-isopentyloxy group Phenyloxy group, 4-n-hexyloxyphenyloxy group, 4-n-
Octyloxyphenyloxy group, 4-n-decyloxyphenyloxy group, 4-n-dodecyloxyphenyloxy group, 4-cyclohexyloxyphenyloxy group,

4-methoxymethylphenyloxy group, 4-ethoxymethylphenyloxy group, 4-n-butoxymethylphenyloxy group, 4- (2'-methoxyethyl) phenyloxy group, 4- (2'-ethoxyethyl (Oxy) phenyloxy group, 4- (2'-n-butoxyethyloxy) phenyloxy group, 4- (3'-ethoxypropyloxy) phenyloxy group, 4-vinyloxyphenyloxy group, 4-allyloxyphenyloxy Group, 4- (4'-pentenyloxy) phenyloxy group, 4-allyloxymethylphenyloxy group, 4-
(2'-allyloxyethyloxy) phenyloxy group,

4-fluorophenyloxy group, 3-fluorophenyloxy group, 2-fluorophenyloxy group, 4-chlorophenyloxy group, 3-chlorophenyloxy group, 2-
Chlorophenyloxy group, 4-bromophenyloxy group,
4-nitrophenyloxy group, 3-nitrophenyloxy group, 4-formylphenyloxy group, 3-formylphenyloxy group, 2-formylphenyloxy group, 4-cyanophenyloxy group, 2-cyanophenyloxy group, 4 -Hydroxyphenyloxy group,

2-chloro-4-nitrophenyloxy group, 4-
Chloro-2-nitrophenyloxy group, 2-chloro-4-methylphenyloxy group, 4-chloro-2-methylphenyloxy group, 4-chloro-3-methylphenyloxy group, 2-methoxy-
4-nitrophenyloxy group, 2,4-dichlorophenyloxy group, 3,4-dichlorophenyloxy group, 3,5-dichlorophenyloxy group, 2,4,6-trichlorophenyloxy group,

Methylthio group, ethylthio group, n-propylthio group, isopropylthio group, n-butylthio group, isobutylthio group, sec-butylthio group, tert-butylthio group, n
-Pentylthio group, isopentylthio group, n-hexylthio group, 1-methylpentylthio group, 4-methyl-2-pentylthio group, 2-ethylbutylthio group, n-heptylthio group, 1-
Methylhexylthio group, n-octylthio group, 1-methylheptylthio group, 2-ethylhexylthio group, n-nonylthio group, 2,6-dimethyl-4-heptylthio group, 3,5,5-trimethylhexylthio group, n-decylthio group, 1-ethyloctylthio group, n-undecylthio group, 1-methyldecylthio group,
n-dodecylthio group, n-tridecylthio group, n-tetradecylthio group, n-pentadecylthio group, n-hexadecylthio group, n-heptadecylthio group, n-octadecylthio group, cyclopentylthio group, cyclohexylthio group, 4- Methylcyclohexylthio group, 3-methylcyclohexylthio group, 2-methylcyclohexylthio group, 2,5-dimethylcyclohexylthio group, 2,6-dimethylcyclohexylthio group, 3,4-dimethylcyclohexylthio group, 3,5- Dimethylcyclohexylthio group, 3,3,5-trimethylcyclohexylthio group, 4-tert-butylcyclohexylthio group, 3-ter
t-butylcyclohexylthio group, cycloheptylthio group, cyclooctylthio group, cyclohexylmethylthio group, 2-cyclohexylethylthio group, bornelthio group,
Isobornerthio group, 2-norbornanemethylthio group, 1-
Adamantylmethylthio group,

2-methoxyethylthio group, 2-ethoxyethylthio group, 2-isopropoxyethylthio group, 2-n-butoxyethylthio group, 2-n-pentyloxyethylthio group, 2-
n-hexyloxyethylthio group, 2-n-heptyloxyethylthio group, 2-n-octyloxyethylthio group, 2-n-decyloxyethylthio group, 2-n-dodecyloxyethylthio group, 2- Cyclohexyloxyethylthio group, 3-methoxypropylthio group, 3-ethoxypropylthio group, 3-n-propoxypropylthio group, 3-n-butoxypropylthio group, 3-n-hexyloxypropylthio group, 3- n-octyloxypropylthio group, 3-cyclohexyloxypropylthio group, 4-ethoxybutylthio group, 5-methoxypentylthio group, 6-ethoxyhexylthio group, 2-methoxyethoxyethylthio group, 2-ethoxyethoxyethyl Thio group,
2-n-butoxyethoxyethylthio group, 3-ethoxyethoxypropylthio group,

2-allyloxyethylthio group, 2- (4'-pentenyl) oxyethylthio group, 3-allyloxypropylthio group, 4-allyloxybutylthio group, vinylthio group,
Allylthio group, 2-butenylthio group, 3-butenylthio group,
1-methyl-4-pentenylthio group, 2-pentenylthio group, 4
-Pentenylthio group, 1-methyl-2-butenylthio group, 2-hexenylthio group, 3-hexenylthio group, 4-hexenylthio group, 5-hexenylthio group, 2-heptenylthio group, 1-vinylhexylthio group, 3-nonenylthio group, 6-nonenylthio group, 9-decenylthio group, 10-undecenylthio group, 1-
A cyclohexenylthio group,

Phenylthio group, 4-methylphenylthio group, 4-ethylphenylthio group, 4-n-propylphenylthio group, 4-isopropylphenylthio group, 4-n-butylphenylthio group, 4-sec-butyl Phenylthio group, 4-tert-butylphenylthio group, 4-n-pentylphenylthio group, 4-
Isopentylphenylthio group, 4-n-hexylphenylthio group, 4-n-heptylphenylthio group, 4-n-octylphenylthio group, 4-tert-octylphenylthio group, 4-n-decylphenylthio group , 4-n-dodecylphenylthio group, 4-
Cyclopentylphenylthio group, 4-cyclohexylphenylthio group, 4-allylphenylthio group, 4-methoxyphenylthio group, 4-isopropoxyphenylthio group, 4-n-butoxyphenylthio group, 4-isobutoxyphenylthio group , 4-n-pentyloxyphenylthio group, 4-isopentyloxyphenylthio group, 4-n-hexyloxyphenylthio group, 4-n-octyloxyphenylthio group, 4-n-decyloxyphenylthio group, 4-n-dodecyloxyphenylthio group, 4-cyclohexyloxyphenylthio group,

4-methoxymethylphenylthio group, 4-ethoxymethylphenylthio group, 4-n-butoxymethylphenylthio group, 4- (2'-methoxyethyl) phenylthio group, 4-
(2'-ethoxyethyloxy) phenylthio group, 4- (2'-n-
Butoxyethyloxy) phenylthio group, 4- (3'-ethoxypropyloxy) phenylthio group, 4-vinyloxyphenylthio group, 4-allyloxyphenylthio group, 4- (4'-
Pentenyloxy) phenylthio group, 4-allyloxymethylphenylthio group, 4- (2'-allyloxyethyloxy) phenylthio group,

4-fluorophenylthio group, 3-fluorophenylthio group, 2-fluorophenylthio group, 4-chlorophenylthio group, 3-chlorophenylthio group, 2-chlorophenylthio group, 4-bromophenylthio group,

4-nitrophenylthio group, 3-nitrophenylthio group, 4-formylphenylthio group, 3-formylphenylthio group, 2-formylphenylthio group, 4-cyanophenylthio group, 2-cyanophenylthio group Group, 4-hydroxyphenylthio group, 2-chloro-4-nitrophenylthio group, 4-
Chloro-2-nitrophenylthio group, 2-chloro-4-methylphenylthio group, 4-chloro-2-methylphenylthio group, 4-
Chloro-3-methylphenylthio group, 2-methoxy-4-nitrophenylthio group, 2,4-dichlorophenylthio group, 3,4-dichlorophenylthio group, 3,5-dichlorophenylthio group,
Examples include 2,4,6-trichlorophenylthio group and the like.

The compound represented by the general formula (1) according to the present invention has the 2-benzoylbenzoic acid skeleton in which the benzene ring in the benzoyl group is substituted with the substituent R1. The substitution position is a position at the para position, meta position or ortho position with respect to the carbonyl group, and specifically, the following general formula (1-a), general formula (1-b) or general formula (1-c ) Is a benzoic acid derivative.

[0029]

[Chemical 4]

[0030]

[Chemical 5]

[0031]

[Chemical 6] (In the formula, X ₁ , X ₂ , X ₃ , X ₄ , Y ₁ , Y ₂ and R ₁ are the same as above)

Among the above-mentioned compounds, the benzoic acid derivative represented by the general formula (1-a) is particularly preferable.

Specific examples of the compound represented by the general formula (1) include the benzoic acid derivatives listed below, but the present invention is of course not limited thereto.

Exemplified Compound No. 1. 2- (4'-phenyloxybenzoyl) benzoic acid 2. 2- [4 '-(4 "-methylphenyloxy) benzoyl] benzoic acid 3. 2- [4'-(4" -ethylphenyloxy) benzoyl] benzoic acid 4. 2- [4 '-(4 "-n-propylphenyloxy) benzoyl] benzoic acid 5. 2- [4'-(4" -isopropylphenyloxy) benzoyl] benzoic acid 6. 2- [4 '-(4 "-n-butylphenyloxy) benzoyl]
Benzoic acid 7. 2- [4 '-(4 "-tert-butylphenyloxy) benzoyl] benzoic acid 8. 2- [4'-(4" -n-pentylphenyloxy) benzoyl] benzoic acid 9. 2- [4 '-(4 "-n-hexylphenyloxy) benzoyl] benzoic acid 10. 2- [4'-(4" -n-octylphenyloxy) benzoyl] benzoic acid 11. 2- [4 '-(4 "-n-decylphenyloxy) benzoyl] benzoic acid 12. 2- [4'-(4" -cyclohexylphenyloxy) benzoyl] benzoic acid 13. 2- [4 '-(4 "-vinylphenyloxy) benzoyl]
Benzoic acid 14. 2- [4 '-(4 "-allylphenyloxy) benzoyl]
Benzoic acid 15. 2- [4 '-(4 "-methoxyphenyloxy) benzoyl] benzoic acid 16. 2- [4'-(4" -tert-butoxyphenyloxy) benzoyl] benzoic acid 17. 2- [4 '-(4 "-n-octyloxyphenyloxy)
Benzoyl] benzoic acid 18. 2- [4 '-(4 "-methoxymethylphenyloxy) benzoyl] benzoic acid 19. 2- [4'-(4" -allyloxyphenyloxy) benzoyl] benzoic acid 20. 2- [4 '-(4 "-allyloxymethyloxyphenyloxy) benzoyl] benzoic acid

21. 2- [4 '-(4 "-fluorophenyloxy) benzoyl] benzoic acid 22. 2- [4'-(4" -chlorophenyloxy) benzoyl]
Benzoic acid 23. 2- [4 '-(4 "-bromophenyloxy) benzoyl]
Benzoic acid 24. 2- [4 '-(4 "-nitrophenyloxy) benzoyl]
Benzoic acid 25. 2- [4 '-(4 "-formylphenyloxy) benzoyl] benzoic acid 26. 2- [4'-(4" -hydroxyphenyloxy) benzoyl] benzoic acid 27. 2- [4 '-(4 "-cyanophenyloxy) benzoyl]
Benzoic acid 28. 2- [4 '-(2 ", 4" -dichlorophenyloxy) benzoyl] benzoic acid 29. 2- (4'-methylthiobenzoyl) benzoic acid 30. 2- (4'-n-butylthiobenzoyl) benzoic acid 31. 2- (4'-n-octylthiobenzoyl) benzoic acid 32. 2- (4'-cyclohexylthiobenzoyl) benzoic acid 33. 2- (4'-methylcyclohexylthiobenzoyl)
Benzoic acid 34. 2- [4 '-(4 "-tert-butylcyclohexylthio) benzoyl] benzoic acid 35. 2- [4'-(2" -cyclohexylethylthio) benzoyl] benzoic acid 36. 2- [4 '-(2 "-methoxyethylthio) benzoyl] benzoic acid 37. 2- [4'-(2" -cyclohexyloxyethylthio)
Benzoyl] benzoic acid 38. 2- [4 '-(2 "-methoxyethoxyethylthio) benzoyl] benzoic acid 39. 2- [4'-(2" -allyloxyethylthio) benzoyl] benzoic acid 40. 2- [4 '-(3 "-allyloxypropylthio) benzoyl] benzoic acid

41. 2- (2'-methylthio-5'-chlorobenzoyl) benzoic acid 42. 2- (3'-nitro-4'-ethylthiobenzoyl) benzoic acid 43. 2- (3'-nitro-4'-n-butylthiobenzoyl) benzoic acid 44. 2- (4'-allylthiobenzoyl) benzoic acid 45. 2- [4 '-(2 "-cyclohexenylthio) benzoyl]
Benzoic acid 46. 2- (4'-phenylthiobenzoyl) benzoic acid 47. 2- [4 '-(4 "-methylphenylthio) benzoyl] benzoic acid 48. 2- [4'-(4" -tert-butylphenylthio) benzoyl] benzoic acid 49. 2- [4 '-(4 "-cyclohexylphenylthio) benzoyl] benzoic acid 50. 2- [4'-(4" -allylphenylthio) benzoyl] benzoic acid 51. 2- [4 '-(4 "-methoxyphenylthio) benzoyl]
Benzoic acid 52. 2- [4 '-(4 "-cyclohexyloxyphenylthio) benzoyl] benzoic acid 53. 2- [4'-(4" -fluorophenylthio) benzoyl]
Benzoic acid 54. 2- [4 '-(4 "-chlorophenylthio) benzoyl] benzoic acid 55. 2- [4'-(3" -chlorolophenylthio) benzoyl]
Benzoic acid 56. 2- [4 '-(2 "-chlorophenylthio) benzoyl] benzoic acid 57. 2- [4'-(3" -bromophenylthio) benzoyl] benzoic acid 58. 2- [4 '-(4 "-nitrophenylthio) benzoyl] benzoic acid 59. 2- [4'-(4" -formylphenylthio) benzoyl]
Benzoic acid 60. 2- [4 '-(4 "-cyanophenylthio) benzoyl] benzoic acid

61. 2- [4 '-(4 "-hydroxyphenylthio) benzoyl] benzoic acid 62. 2- [4'-(2" -chloro-4 "-nitrophenylthio) benzoyl] benzoic acid 63. 2- [4 ' -(2 "-chloro-4" -methylphenylthio) benzoyl] benzoic acid 64. 2- [4 '-(2 "-methoxy-4" -nitrophenylthio)
Benzoyl] benzoic acid 65. 2- [4 '-(2 ", 4" -dichlorophenylthio) benzoyl] benzoic acid 66. 2- (4'-phenyloxybenzoyl) -3-methylbenzoic acid 67. 2- (4'-phenyloxybenzoyl) -4-methoxybenzoic acid 68. 2- (4'-phenyloxybenzoyl) -4-chlorobenzoic acid 69. 2- (4'-phenylthiobenzoyl) -4-nitrobenzoic acid 70. 2- (4'-phenyloxybenzoyl) -3,4,5,6-tetrachlorobenzoic acid 71. 2- (4'-methylthiobenzoyl) -3,4,5,6-tetrachlorobenzoic acid 72. 2- (4'-allylthiobenzoyl) -3,4,5,6-tetrachlorobenzoic acid 73. 2- (4'-phenylthiobenzoyl) -3,4,5,6-tetrachlorobenzoic acid

The benzoic acid derivative represented by the general formula (1) can be produced by a method known per se [eg, Journal.
al of Organic Chemistry, 2
Volume 3, p. 206 (1958) or Journal o
f American Chemical Society
ty, 77, 1909 (1955)]
Can be manufactured by. That is, typically,
For example, it is preferably produced by reacting the phthalic anhydride derivative represented by the general formula (2) with the compound represented by the general formula (3) in the presence of a Lewis acid catalyst (eg, aluminum chloride). You can

[0039]

[Chemical 7] (Wherein X ₁ , X ₂ , X ₃ and X ₄ are the same as above)

[0040]

[Chemical 8] (In the formula, Y ₁ , Y ₂ and R ₁ are the same as above)

After the completion of the reaction, the product can be obtained by carrying out the usual post-treatment operations described in the above-mentioned documents and the like, and if desired by a known purification method (eg recrystallization, column chromatography). The purity can be further increased.

In the metal salt of the benzoic acid derivative represented by the general formula (1), the metal salt includes alkali metal salts such as sodium, potassium and lithium. The metal salt is a thermosensitive recording material. When used as the electron-accepting compound (1), it is preferably a sparingly water-soluble or water-insoluble divalent, trivalent or tetravalent metal salt (polyvalent metal salt), and more preferably a divalent metal salt.

Specific examples of polyvalent metal salts include zinc, magnesium, calcium, barium, nickel, tin,
Copper, manganese, cobalt, titanium, aluminum, iron salts can be mentioned, preferably zinc, magnesium, calcium, barium, nickel, manganese, cobalt, aluminum salts, more preferably zinc, calcium, A manganese salt, particularly a zinc salt, is preferable.

The polyvalent metal salt is usually represented by the general formula (1)
An alkali metal salt of a benzoic acid derivative represented by (for example,
Of a slightly water-soluble or water-insoluble benzoic acid derivative by a metathesis method from an aqueous solution of a metal salt such as sodium, potassium or lithium) and an aqueous solution of a corresponding water-soluble divalent, trivalent or tetravalent polyvalent metal compound. It is produced as a valent metal salt. At this time, heating may be performed or an organic solvent may coexist as desired.

As the aqueous solution of the alkali metal salt of the benzoic acid derivative represented by the general formula (1), a plurality of different aqueous solutions of the alkali metal salt of the benzoic acid derivative represented by the general formula (1) are used. Well, for example, 2- (4'-phenyloxybenzoyl) benzoic acid and 2- (4'-phenylthiobenzoyl) benzoic acid alkali metal salt mixed aqueous solution, 2- [4 '-(4'- [Chlorophenyloxy) benzoyl)] benzoic acid and 2- (4′-allylthiobenzoyl) benzoic acid prepared by using a mixed aqueous solution of respective alkali metal salt aqueous solutions are also included in the thermosensitive recording material of the present invention. Can be suitably used.

Examples of the water-soluble polyvalent metal compounds include sulfates such as zinc sulfate, magnesium sulfate, calcium sulfate and aluminum sulfate, zinc chloride, magnesium chloride, calcium chloride, barium chloride, nickel chloride and cobalt chloride. Examples thereof include chlorides such as aluminum chloride and acetates such as zinc acetate and manganese acetate.

The metal salt of the benzoic acid derivative represented by the general formula (1) produced as described above depends on the type of the benzoic acid derivative represented by the general formula (1), the type of metal or the production conditions. Occasionally, a solvate such as a hydrate may be formed, and the solvate can also be suitably used for the heat-sensitive recording material of the present invention. Of course, a metal salt of a benzoic acid derivative obtained by removing a solvent such as water from the solvate can be produced by a known method (for example, drying), and, of course, a benzoic acid derivative of the solvate can be prepared. Metal salts can also be suitably used in the heat-sensitive recording material of the present invention.

The heat-sensitive recording material of the present invention is a heat-sensitive recording material containing an electron-donating color forming compound and an electron-accepting compound, and the electron-accepting compound is a benzoic acid derivative represented by the general formula (1) or Although at least one metal salt of a derivative is contained, it is preferable that the heat-sensitive recording material further contains a metal compound because the storage stability of a color image can be improved.

Specific examples of the metal compound are divalent,
Trivalent or tetravalent metals such as zinc, magnesium,
Barium, calcium, aluminum, tin, titanium,
Examples thereof include oxides, hydroxides, sulfides, halides, carbonates, phosphates, silicates, sulfates and nitrates of metals selected from nickel, cobalt, manganese, iron and the like. Particularly, zinc compounds are preferable.

Specific examples of the metal compound include zinc oxide, zinc hydroxide, zinc aluminate, zinc sulfide, zinc carbonate, zinc phosphate, zinc silicate, zinc thiocyanate, magnesium sulfate, magnesium aluminate, and hydroxide. Examples thereof include magnesium, magnesium oxide, magnesium carbonate, barium carbonate, calcium sulfate, calcium chloride, calcium carbonate, aluminum oxide, aluminum hydroxide, aluminum silicate, aluminum phosphate, tin oxide and titanium oxide. These metal compounds may be used alone or in combination. Particularly preferred are zinc carbonate and zinc oxide.

The amount of these metal compounds used is not particularly limited, but usually 100 parts by weight of a benzoic acid derivative represented by the general formula (1) or a metal salt of the derivative used as an electron-accepting compound is used. For 1 to 50
It is desirable to use 0 part by weight, preferably 3 to 300 parts by weight.

The method of incorporating the metal compound into the heat-sensitive recording material of the present invention is not particularly limited, but for example, a benzoic acid derivative represented by the general formula (1) or a metal of the derivative is used. The salt and premixed mixture,
A method in which a dispersion obtained by dispersion treatment or a benzoic acid derivative represented by the general formula (1) or a metal salt of the derivative is dispersed and the obtained dispersion is applied on a support is applied. It

The method and conditions for preparing the mixture are not particularly limited. For example, the benzoic acid derivative represented by the general formula (1) or the metal salt of the derivative and the metal compound may be mixed and prepared in a solid state, or may be mixed and prepared in the presence of water. Good.

When preparing the mixture, it is not necessary to perform heat treatment, but it is preferable to perform heat treatment for preparation.
The heat treatment temperature may be a temperature equal to or higher than the melting point of the benzoic acid derivative represented by the general formula (1) or a metal salt of the derivative, but is preferably a temperature lower than the melting point, more preferably a general formula ( The temperature is 5 ° C. or more lower than the melting point of the benzoic acid derivative represented by 1) or the metal salt of the derivative, more preferably 25 ° C. to 5 ° C. or more lower than the melting point, and particularly preferably 25 ° C. The temperature is 10 ° C. or more lower than the melting point. The heat treatment time is not particularly limited and may be 1 minute or more. The heat treatment for a long time only lowers the production efficiency, and is usually about 1 minute to 10 hours, more preferably about 5 minutes to 5 hours. Alternatively, they may be mixed and prepared in the presence of water. Moreover, when mixing in the presence of water, it may be carried out in the presence of a binder, a surfactant and the like, and the mixing treatment temperature is not particularly limited, but is usually 20 to 100.
℃.

When a heat-fusible compound (sensitizer) is used together in the production of the heat-sensitive recording material of the present invention, the mixture can be prepared in the presence of the heat-fusible compound. . When the mixture is prepared, it is not necessary to stir and mix, but it is preferable to stir and mix using an appropriate stirrer and mixer. Stirring, as the mixing device, for example, a mortar, a propeller-type stirrer, a turbine-type stirrer, a paddle-type stirrer, a homogenizer, a homomixer, a line mixer, stirring without using a medium such as a line homomixer,
Mixing device, agitator mill such as attritor, Sentry mill, sand grinder, crane mill,
A mixing and stirring device filled with media (for example, glass beads, ceramic balls, steel balls, etc.) such as a flow tube type mill such as a pearl mill, a matter mill, a dyno mill, an annular type continuous wet stirring mill such as a conical ball mill, an annular mill, etc. be able to.

Usually, the mixture can be prepared under atmospheric pressure, but may be prepared under reduced pressure or under pressure, if desired. Furthermore, if desired, the mixture can be prepared under an atmosphere of an inert gas such as nitrogen gas, argon gas, or helium gas.

In the heat-sensitive recording material of the present invention, the proportions of the electron-donating color-forming compound and the electron-accepting compound used are not particularly limited, but usually 100 parts by weight of the electron-donating color-forming compound are used. Electron-accepting compound 50
It is desirable to use ˜700 parts by weight, preferably 100 to 500 parts by weight.

Examples of the colorless or light-colored electron-donating color-forming compound used in the present invention include triarylmethane compounds, diarylmethane compounds, rhodamine-lactam compounds, fluorane compounds, indolylphthalide compounds, divinyl. Examples thereof include various known electron-donating color-forming compounds such as phthalide compounds, pyridine compounds, spiro compounds, fluorene compounds and thiazine compounds.

Among the above-mentioned electron-donating color-forming compounds,
A fluoran compound is preferable, and a fluoran compound represented by formula (A) is more preferable.

[0060]

[Chemical 9] (In the formula, A and B are an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkoxyalkyl group having 2 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, or a tetrahydrofurfuryl group. Further, A and B may be bonded to form a pyrrolidine ring, a piperidine ring or a morpholine ring, and X is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or Represents a halogen atom, Y and Z are hydrogen atom, halogen atom, carbon number 1
Represents an alkyl group or a trifluoromethyl group of 4)

To give some specific examples of the electron-donating color-forming compound, the triarylmethane compounds are:
For example, 3,3-bis (4'-dimethylaminophenyl) -6-dimethylaminophthalide ["Crystal violet lactone"], 3,3-bis (4'-dimethylaminophenyl) phthalide, 3- (4 ' -Dimethylaminophenyl) -3- (4 "-diethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis
(9'-Ethylcarbazol-3'-yl) -6-dimethylaminophthalide, 3- (4'-dimethylaminophenyl) -3- (1 "-methylpyrrole-3" -yl) -6-dimethylamino There are phthalides.

Examples of the diarylmethane compound include 4,4-bis-dimethylaminobenzhydrin benzyl ether, N-halophenyl-leukoauramine, N- (2,4,
5-trichlorophenyl) leuco auramine.

As the rhodamine-lactam compound,
For example, Rhodamine-B-anilinolactam, Rhodamine-
Examples include (4-nitroanilino) lactam and rhodamine-B- (2-chloroanilino) lactam.

Fluoran compounds include, for example, 3,
6-dimethoxyfluorane, 3-diethylamino-6-methoxyfluorane, 3-dimethylamino-7-methoxyfluorane, 3-diethylamino-7-methylfluorane, 3-N-cyclohexyl-Nn-butylamino-7- Methylfluorane, 3-
N-ethyl-N-isopentylamino-7-methylfluorane,
3-diethylamino-7-methoxyfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6,7-dimethylfluorane, 3,6- Bis (diphenylamino) fluorane,

3-diethylamino-7-dibenzylaminofluorane, 3-di-n-butylamino-7-dibenzylaminofluorane, 3-diethylamino-7-di-n-hexylaminofluorane, 3-diethylamino -7-n-octylaminofluorane, 3-diethylamino-7-anilinofluorane, 3-N
-Ethyl-N-isopentylamino-7-anilinofluorane, 3-diethylamino-7- (2'-chlorophenylamino) fluorane, 3-diethylamino-7- (3'-chlorophenylamino) fluorane, 3-diethylamino- 7- (2 ', 3'-dichlorophenylamino) fluorane, 3-diethylamino-7-
(3'-trifluoromethylphenylamino) fluorane, 3
-Di-n-butylamino-7- (2'-chlorophenylamino) fluorane,

3-diethylamino-7- (2'-fluorophenylamino) fluorane, 3-di-n-butylamino-7- (2'-fluorophenylamino) fluorane, 3-diethylamino-
6-chloro-7-anilinofluorane, 3-di-n-butylamino
-6-chloro-7-anilinofluorane, 3-diethylamino-6
-Methoxy-7-anilinofluorane, 3-di-n-butylamino-6-ethoxy-7-anilinofluorane,

3-pyrrolidino-6-methyl-7-anilinofluorane, 3-morpholino-6-methyl-7-anilinofluorane,
3-Dimethylamino-6-methyl-7-anilinofluorane, 3-
Diethylamino-6-methyl-7-anilinofluorane, 3-di
-n-Butylamino-6-methyl-7-anilinofluorane, 3-
Di-n-pentylamino-6-methyl-7-anilinofluorane, 3-di-n-octylamino-6-methyl-7-anilinofluorane, 3-Nn-propyl-N-methylamino-6 -Methyl-7-
Anilinofluorane, 3-Nn-butyl-N-methylamino-6-
Methyl-7-anilinofluorane, 3-Nn-butyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-N-isobutyl-N-methylamino-6-methyl-7-anilino Fluoran, 3
-N-isobutyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-Nn-pentyl-N-ethylamino-6-methyl-7
-Anilinofluorane, 3-N-isopentyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-Nn-hexyl-N
-Ethylamino-6-methyl-7-anilinofluorane, 3-Nn
-Octyl-N-ethylamino-6-methyl-7-anilinofluorane,

3-N-cyclopentyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-N-cyclohexyl-N-methylamino-6-methyl-7-anilinofluorane, 3-N -Cyclohexyl-Nn-propylamino-6-methyl-7-anilinofluorane, 3-N-cyclohexyl-Nn-butylamino-6-
Methyl-7-anilinofluorane, 3-N-cyclohexyl-N-
n-hexylamino-6-methyl-7-anilinofluorane, 3-
N-cyclohexyl-Nn-octylamino-6-methyl-7-anilinofluorane,

3-N- (2'-methoxyethyl) -N-isobutylamino-6-methyl-7-anilinofluorane, 3-N- (2'-ethoxyethyl) -N-ethylamino-6- Methyl-7-anilinofluorane, 3-N- (3'-methoxypropyl) -N-methylamino-6-
Methyl-7-anilinofluorane, 3-N- (3'-methoxypropyl) -N-ethylamino-6-methyl-7-anilinofluorane, 3-N- (3'-ethoxypropyl) -N -Methylamino-6-methyl-7-anilinofluorane, 3-N- (3'-ethoxypropyl) -N-ethylamino-6-methyl-7-anilinofluorane,
3-N- (2'-tetrahydrofurfuryl) -N-ethylamino-6-
Methyl-7-anilinofluorane, 3-N- (4'-methylphenyl) -N-ethylamino-6-methyl-7-anilinofluorane,

3-Diethylamino-6-ethyl-7-anilinofluorane, 3-diethylamino-6-methyl-7- (3'-methylphenylamino) fluorane, 3-diethylamino-6-methyl
-7- (2 ', 6'-Dimethylphenylamino) fluorane, 3-di-
n-butylamino-6-methyl-7- (2 ', 6'-dimethylphenylamino) fluorane, 3-di-n-butylamino-7- (2', 6'-dimethylphenylamino) fluorane, 2, 2-bis [4 '-(3 "-N
-Cyclohexyl-N-methylamino-6 "-methylfluorane
-7 "-yl) aminophenyl] propane, 3- [4 '-(4" -phenylaminophenyl) aminophenyl] amino-6-methyl-7-
For example, chlorofluoran.

Examples of indolylphthalide compounds include 3,3-bis (1 ', 2'-dimethylindol-3'-yl) -5.
-Dimethylaminophthalide, 3,3-bis (1 ', 2'-dimethylindol-3'-yl) -6-dimethylaminophthalide, 3,3-bis (2'-phenylindol-3'-yl) ) -6-Dimethylaminophthalide, 3,3-bis (1'-ethyl-2'-methylindole-
3'-yl) phthalide, 3,3-bis (1'-octyl-2'-methylindol-3'-yl) phthalide, 3- (4'-dimethylaminophenyl) -3- (1 ", 2" -Dimethylindol-3 "-yl) phthalide, 3- (4'-dimethylaminophenyl) -3- (2" -methylindol-3 "-yl) phthalide, 3- (2'-ethoxy-4'-diethylamino Phenyl) -3- (1 "-ethyl-2" -methylindole
-3 "-yl) phthalide, 3- (2'-ethoxy-4'-dibutylaminophenyl) -3- (1" -ethyl-2 "-methylindol-3" -yl) phthalide, 3- (2 '-Ethoxy-4'-diethylaminophenyl) -3- (1 "-octyl-2" -methylindol-3 "-yl)
There are phthalides.

Examples of the divinylphthalide compound include 3,3-bis [2 ', 2'-bis (4 "-dimethylaminophenyl)
Ethenyl] -4,5,6,7-tetrachlorophthalide, 3,3-bis
[2 ', 2'-bis (4 "-pyrrolidinophenyl) ethenyl] -4,5,6,
7-Tetrabromophthalide, 3,3-bis [2 '-(4 "-methoxyphenyl) -2'-(4 '"-dimethylaminophenyl) ethenyl]-
4,5,6,7-Tetrachlorophthalide, 3,3-bis [2 '-(4 "-methoxyphenyl) -2'-(4 '"-pyrrolidinophenyl) ethenyl]
-4,5,6,7-tetrachlorophthalide etc.

Examples of the pyridine compound include 3-
(2'-Ethoxy-4'-diethylaminophenyl) -3- (1 "-ethyl-2""-methylindol-3-yl) -4 or 7-azaphthalide, 3- (2'-ethoxy-4'- Diethylaminophenyl) -3-
(1 "-ethyl-2" -phenylindol-3 "-yl) -4 or 7
-Azaphthalide, 3- (2'-ethoxy-4'-diethylaminophenyl) -3- (1 "-octyl-2" -methylindol-3 "-yl) -4 or 7-azaphthalide, 3- (2'- Hexyloxy-4 '
-Diethylaminophenyl) -3- (1 "-ethyl-2" -methylindol-3 "-yl) -4 or 7-azaphthalide, 3- (2 ''-n-
Butoxy-4-diethylaminophenyl) -3- (1 "-ethyl-2"
-Phenylindole-3 "-yl) -4 or 7-azaphthalide, 3- (4'-diethylamino-2'-methylphenyl) -3- (1"-
Ethyl-2 "-methylindol-3" -yl) -4 or 7-azaphthalide, 3- (4 ''-diethylamino-2-methylphenyl)-
3- (1 "-n-octyl-2" -methylindol-3 "-yl) -4 or 7-azaphthalide, 3,3-bis (4'-diethylamino-2'-
Methoxyphenyl) -4 or 7-azaphthalide, 3,3-bis
(4'-diethylamino-2'-ethoxyphenyl) -4 or 7-
There is azaphthalide.

Examples of the spiro compound include 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3-phenyl-spiro-dinaphthopyran, 3-benzyl-spiro-dinaphthopyran, 3-methyl-naphtho- ( Examples include 3'-methoxybenzo) spiropyran and 3-propyl-spiro-dibenzopyran.

Examples of the fluorene compound include 3,
6-bis (dimethylamino) fluorene-9-spiro-3 '-(6'-
Dimethylamino) phthalide, 3-diethylamino-6- (N-allyl-N-methylamino) fluorene-9-spiro-3 '-(6'-dimethylamino) phthalide, 3,6-bis (dimethylamino) -spiro [Fluorene-9,6'-6'H-chromeno (4,3-b) indole], 3,6-bis (dimethylamino) -3'-methyl-spiro [fluorene-9,6'-6'H -Kromeno (4,3-b) indole], 3,6
-Bis (diethylamino) -3'-methyl-spiro [fluorene-
9,6'-6'H-chromeno (4,3-b) indole] etc.

Examples of thiazine compounds include benzoyl leuco methylene blue and 4-nitrobenzoyl leuco methylene blue.

These electron-donating color forming compounds may be used alone or in combination.

As the electron-donating color forming compound,
Fluoran compounds that develop black color are preferable, and among them,
Preferably, di-n-butylamino-7- (2'-chlorophenylamino) fluorane, 3-dimethylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinoflu Oran, 3-di-n-butylamino-6-methyl-7-anilinofluorane, 3-di-n-pentylamino-6-methyl-7
-Anilinofluorane, 3-Nn-propyl-N-methylamino
-6-Methyl-7-anilinofluorane, 3-Nn-butyl-N-methylamino-6-methyl-7-anilinofluorane, 3-N-isobutyl-N-methylamino-6-methyl-7 -Anilinofluorane, 3-N-isobutyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-N-isopentyl-N-ethylamino-6-
Methyl-7-anilinofluorane, 3-N- (2'-methoxyethyl) -N-isobutylamino-6-methyl-7-anilinofluorane, 3-N- (3'-ethoxypropyl) -N -Ethylamino-6-methyl-7-anilinofluorane and 3-diethylamino-6-methyl-7- (3'-methylphenylamino) fluorane.

The heat-sensitive recording material of the present invention is characterized by containing at least one benzoic acid derivative represented by the general formula (1) or a metal salt of the derivative as an electron-accepting compound. It is also possible to use other electron-accepting compounds in combination as long as the desired effects of the present invention are not impaired.

In this case, the proportion of the benzoic acid derivative represented by the general formula (1) or the metal salt of the derivative in the total electron-accepting compound is usually 10% by weight or more, preferably 20% by weight or more, More preferably, it is desirable to adjust to 30% by weight or more.

As the electron-accepting compound other than the benzoic acid derivative represented by the general formula (1) or the metal salt of the derivative, a phenol derivative, an organic acid or a metal salt or complex thereof,
Examples thereof include organic electron-accepting compounds such as urea derivatives and inorganic electron-accepting compounds such as acid clay.

Some specific examples of these compounds include, for example, 4-tert-butylphenol, 4-tert-octylphenol, 4-phenylphenol, 1-naphthol, 2-naphthol, hydroquinone, resorcinol,
4-tert-octylcatechol, 2,2'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, 2,2-bis (4'-hydroxyphenyl) propane ["bisphenol A"], 1,1-bis (4 '-Hydroxyphenyl) cyclohexane, 2,2-bis (4'-hydroxy-3'-methylphenyl) propane, 1,3-bis (4'-hydroxycumyl) benzene, 1,4
-Bis (4'-hydroxycumyl) benzene, 1,3,5-tris
(4'-Hydroxycumyl) benzene, 2,2-bis (4'-hydroxyphenyl) acetic acid ethyl ester, 4,4- (4'-hydroxyphenyl) pentanoic acid-n-butyl ester, 4-hydroxybenzoic acid Benzyl ester, 4-hydroxybenzoic acid phenethyl ester, 2,4-dihydroxybenzoic acid phenoxyethyl ester, 4-hydroxyphthalic acid dimethyl ester, gallic acid-n-propyl ester, gallic acid-n-octyl ester, gallic acid-n -Dodecyl ester, gallic acid-n-octadecyl ester, hydroquinone monobenzyl ether, bis (3-methyl-4-hydroxyphenyl)
Sulfide, bis (2-methyl-4-hydroxyphenyl) sulfide, bis (3-phenyl-4-hydroxyphenyl) sulfide, bis (3-cyclohexyl-4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfoxide, Bis (4-hydroxyphenyl) sulfone, bis (3
-Allyl-4-hydroxyphenyl) sulfone, 4-hydroxy-4'-methyldiphenyl sulfone, 4-hydroxy-
4'-tert-butyldiphenylsulfone, 4-hydroxy-
4'-chlorodiphenyl sulfone, 4-hydroxy-4'-methoxydiphenyl sulfone, 4-hydroxy-4'-n-propoxydiphenyl sulfone, 4-hydroxy-4'-isopropoxydiphenyl sulfone, 4-hydroxy-4'- n-Butoxydiphenylsulfone, 4-hydroxy-4'-benzyloxydiphenylsulfone, 3,4-dihydroxy-4'-
Methyldiphenyl sulfone, 2,4'-dihydroxydiphenyl sulfone, 2-methoxy-4'-hydroxydiphenyl sulfone, 2-ethoxy-2'-hydroxydiphenyl sulfone, 4-hydroxy-3-methyl-4'-n-propoxydiphenyl Sulfone, bis (2-hydroxy-5-tert-butylphenyl) sulfone, bis (2-hydroxy-5-chlorophenyl) sulfone, bis [4- (3'-hydroxyphenyloxy) phenyl] sulfone, 4-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 1,7-bis
(4'-hydroxyphenylthio) -3,5-dioxaheptane,
Phenol derivatives such as 1,5-bis (4'-hydroxyphenylthio) -3-oxapentane, or metal salts of these phenol derivatives (for example, metal salts of nickel, zinc, aluminum, magnesium, calcium, titanium, etc.),

For example, salicylic acid, 3-isopropylsalicylic acid, 3-cyclohexylsalicylic acid, 3,5-di-tert-butylsalicylic acid, 3,5-di-α-methylbenzylsalicylic acid, 3-methyl-5-α-methylbenzyl Salicylic acid, 4- [2'-
(4 "-methoxyphenyloxy) ethyloxy] salicylic acid, 4- [3 '-(4" -methylphenylsulfonyl) propyloxy] salicylic acid, 4- [3'-(4 "-methoxyphenylsulfonyl) propyloxy] salicylic acid, 5- {4 '-[2 "-(4'"-methoxyphenyloxy) ethyloxy] cumyl} salicylic acid, 1-naphthoic acid, 2-naphthoic acid, 2-hydroxy-3-naphthoic acid, 2-hydroxy-6- Naphthoic acid, 6-acetoxy-
2-naphthoic acid, phthalic acid monobenzyl ester, phthalic acid monophenyl ester, isophthalic acid, 4-methylbenzoic acid, 2-benzoylbenzoic acid, 2- (4'-chlorobenzoyl) benzoic acid, 4-nitrobenzoic acid, 4-chlorobenzoic acid, 4
-Organic acids such as formylbenzoic acid or metal salts thereof (for example, metal salts such as nickel, zinc, aluminum, magnesium, calcium and titanium),

Complexes such as zinc thiocyanate antipyrine complex and molybdate acetylacetone complex, for example, N, N'-diphenylthiourea, N, N'-di (3-trifluoromethylphenyl) thiourea, 1,4 Urea such as -di (3'-chlorophenyl) -3-thiosemicarbazide, N-phenyl-'N- (4-methylphenylsulfonyl) urea, 4,4'-bis (4 "-methylphenylsulfonylcarbonylamino) diphenylmethane Organic electron-accepting compounds such as derivatives,

Examples thereof include inorganic clay compounds such as acid clay, attapulgite, colloidal silica, aluminum silicate, activated clay, aluminum chloride, zinc chloride and zinc bromide, but are not limited thereto. . These electron-accepting compounds can be used in combination. Among these, phenol derivatives are particularly preferable electron-accepting compounds.

The heat-sensitive recording material of the present invention is further provided with various known formulations (addition of a heat-fusible compound, etc.) for producing a known heat-sensitive recording material as described below.

In the heat-sensitive recording material of the present invention, a heat-fusible compound (a compound having a melting point of about 70 to 150 ° C., more preferably a melting point of about 80 to 130 ° C.) is optionally added to the heat-sensitive recording material of the present invention. This is preferable for obtaining a heat-sensitive recording material compatible with high speed recording. In this case, the amount of the heat-fusible compound used is not particularly limited, but usually the electron-donating color forming compound 10 is used.
10 to 700 parts by weight of the heat-fusible compound with respect to 0 parts by weight,
It is preferable to use 20 to 500 parts by weight.

Specific examples of the heat-fusible compound include caproic acid amide, capric acid amide, palmitic acid amide, stearic acid amide, oleic acid amide, erucic acid amide, linoleic acid amide, linolenic acid amide, and the like. N-ethylcapric acid amide, N-butyllauric acid amide, N-methylstearic acid amide, N-methyloleic acid amide, N-stearylcyclohexylamide, N-octadecylacetamide, N-oleinacetamide, stearylurea, stearic acid anilide , Benzanilide,
Nitrogen-containing compounds such as linoleic acid anilide, acetoacetic acid anilide, o-acetoacetic acid toluidide, p-acetoacetic acid aniside, N-ethylcarbazole, 4-methoxydiphenylamine, N-hydroxymethylstearic acid amide, ethylenebisstearic acid amide,

For example, 4-benzyloxybenzoic acid benzyl ester, 2-naphthoic acid phenyl ester, 1-hydroxy-2-naphthoic acid phenyl ester, oxalic acid dibenzyl ester, oxalic acid di (4-methylbenzyl) ester, shu Acid di (4-chlorobenzyl) ester, adipic acid diphenyl ester, glutaric acid diphenacyl ester, di (4-methylphenyl) carbonate, terephthalic acid dimethyl ester, terephthalic acid di-n-butyl ester, terephthalic acid dibenzyl ester , Isophthalic acid di
-Ester compounds such as n-butyl ester, isophthalic acid bis (4-benzyloxycarbonylphenyl) ester, bis [2- (benzoyloxy) ethyl] sulfide,

Hydrocarbon compounds such as 4-benzylbiphenyl, m-terphenyl, fluorene, fluoranthene, 2,6-diisopropylnaphthalene, and 3-benzylacenaphthene.

For example, 2-benzyloxynaphthalene, 2-
(4'-methylbenzyloxy) naphthalene, 1,4-diethoxynaphthalene, 1,2-diphenoxyethane, 1,2-bis (3'-
Methylphenoxy) ethane, 1,2-bis (4'-methylphenoxy) ethane, 1-phenoxy-2- (4'-ethylphenoxy)
Ethane, 1- (4'-methoxyphenoxy) -2-phenoxyethane, 1- (4'-methoxyphenoxy) -2- (3'-methylphenoxy) ethane, 1- (4'-methoxyphenoxy) -2- (2'-methylphenoxy) ethane, 1- (4'-methoxyphenoxy) -2-phenoxypropane, 1-phenoxy-2- (4'-methoxyphenoxy) propane, 1,2-bis (4'-methoxyphenoxy) ) Propane, 1,3-bis (4'-methoxyphenoxy) propane, 1
-(4'-methoxyphenoxy) -2- (2'-chlorophenoxy) ethane, 1,4-diphenoxybutane, bis [2- (4'-methoxyphenoxy) ethyl] ether,

4- (4'-methylphenoxy) biphenyl, 1,2
-Diphenoxybenzene, 1,4-diphenoxybenzene,
1,4-bisbenzyloxybenzene, 1,4-bis (2'-chlorobenzyloxy) benzene, 1,4-bis (2'-chlorophenoxy) benzene, 1,4-bis (4'-methylphenoxy) Benzene, 1,4-bis (3'-methylphenoxymethyl) benzene, 4
-(4'-chlorobenzyloxy) ethoxybenzene, 4,4'-
Bis (phenoxy) diphenyl ether, 1,4-bis (4'-benzylphenoxy) benzene, 1,4-bis [(4'-methylphenyloxy) methoxymethyl] benzene,

4- (4'-methoxybenzylthio) anisole, 1-phenoxy-2- (4'-methoxyphenylthio) ethane, 1,2-bis (4'-methoxyphenylthio) ethane, 1- (4 '
-Methylphenoxy) -2- (4'-methoxyphenylthio) ethane, benzyl-4-methylthiophenyl ether, 4,4'-bis (phenoxy) diphenylthioether, 4,4'-di-n-butoxydiphenylsulfone, etc. Ether compounds or sulfur-containing compounds,

For example, 1,4-di (glycidyloxy) benzene, 1,4-diglycidyl terephthalate, 4-glycidyloxy-4'-isopropyloxydiphenyl sulfone, 4-
[(2,3-Epoxy-2-methyl) propyloxy] phenyl-4 '
-(Benzyloxy) phenyl sulfone, a compound having an epoxy group such as 4-[(2,3-epoxy) propyloxy] phenyl-4 '-(4-methylbenzyloxy) diphenylsulfone,

For example, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-tert-
Butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-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-amylphenyl) benzotriazole, 2- (2 '-Hydroxy-5'-te
Examples thereof include, but are not limited to, triazole compounds such as rt-octylphenyl) benzotriazole. These heat-fusible compounds may be used alone or in combination.

The heat-sensitive recording material of the present invention can be manufactured by a known method without using a special method.

Generally, in the presence of water, an electron-donating color-forming compound, a benzoic acid derivative represented by the general formula (1) or a metal salt of the derivative, and, if desired, a heat-fusible compound, A metal compound or the like, together or separately, in a water-soluble binder is mixed with a ball mill, a sand mill, a sand mill (vertical or horizontal type), an attritor, a colloidal mill, or the like, and usually 3 μm or less, preferably 2 μm or less by a pulverizer.
The coating liquid for the heat-sensitive recording layer can be prepared by pulverizing and dispersing to a particle size of μm or less and mixing. In such coating liquid,
The binder is blended in an amount of about 5 to 50% by weight of the total solid content.

As the binder, a water-soluble binder is generally used. For example, polyvinyl alcohol,
Carboxy modified polyvinyl alcohol, sulfonation modified polyvinyl alcohol, polyvinyl alcohol derivatives such as alkyl modified polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, cellulose derivatives such as hydroxypropyl cellulose, epichlorohydrin modified polyamide, ethylene-maleic anhydride copolymer, Styrene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer,
Examples include, but are not limited to, polyacrylic acid, polyacrylamide, methylol-modified polyacrylamide, starch, starch derivatives (oxidized starch, etherified starch, etc.), casein, gelatin, gum arabic and the like.

Further, in the recording layer of the heat-sensitive recording material of the present invention, if necessary, a pigment, a water-insoluble binder, a metal soap, a wax, a surfactant, an ultraviolet absorber, an ultraviolet stabilizer, a crosslinking agent, and a hindered agent. Add phenol, antifoaming agent, etc.

Examples of the pigment include calcium carbonate,
Barium carbonate, magnesium carbonate, zinc carbonate, zinc oxide, aluminum oxide, titanium oxide, aluminum hydroxide, magnesium hydroxide, barium sulfate, talc, wax stone, kaolin, clay, diatomaceous earth, inorganic pigments such as silica, styrene microballs , Nylon particles, urea-
Organic pigments such as formalin filler, polyethylene particles, cellulose filler and starch particles are used.

As the water-insoluble binder, synthetic rubber latex or synthetic resin emulsion is generally used,
For example, styrene-butadiene rubber latex, acrylonitrile-butadiene latex, methyl acrylate-
Butadiene rubber latex, vinyl acetate emulsion and the like are known and used as necessary.

Examples of the metal soap include higher fatty acid metal salts such as zinc stearate, calcium stearate, aluminum stearate and zinc oleate.

Examples of the wax include paraffin wax, microcrystalline wax, carboxy-modified paraffin wax, carnauba wax, polyethylene wax, polystyrene wax, candelilla wax, montan wax, higher fatty acid ester and the like.

As the surfactant (dispersant), for example,
Sulfosuccinic acid-based alkali metal salt (for example, di (n-hexyl) sulfosuccinic acid, sodium salt of di (2-ethylhexyl) sulfosuccinic acid, etc.), sodium salt of dodecylbenzenesulfonic acid, sodium salt of lauryl alcohol sulfate, fatty acid Examples thereof include metal salts and fluorine-containing surfactants.

Examples of ultraviolet absorbers and ultraviolet stabilizers include cinnamic acid derivatives, benzophenone derivatives, triazole derivatives and hindered amine derivatives.

Examples of the crosslinking agent include aldehyde compounds such as glyoxal, epoxy compounds, polyamide resins, diglycidyl compounds, aziridine compounds, magnesium chloride and ferric chloride.

The hindered phenol is preferably a phenol derivative in which at least one ortho position of the phenolic hydroxyl group is substituted with a branched alkyl group, and 1,1,3-tris (2-methyl-4-hydroxy-5- (tert-butylphenyl)
Butane, 1,1,3-Tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) 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, 2,2'-methylene-bis (6-tert-butyl-4-methylphenol), 2,2'-methylene-bis (6-ter
t-butyl-4-ethylphenol), 1,3,5-trimethyl-2,4,
6-tris (3,5-di-tert-butyl-4-hydroxybenzyl)
Benzene, 1,3,5-tris (4-tert-butyl-3-hydroxy-
2,6-Dimethylbenzyl) isocyanuric acid, 1,3,5-tris
(4-tert-butyl-3-hydroxy-2-methyl-6-ethylbenzyl) isocyanuric acid, bis (2-methyl-4-hydroxy-5-
tert-butylphenyl) sulfide and the like.

In the heat-sensitive recording material of the present invention, the method for forming the recording layer is not particularly limited, and the recording layer can be formed according to a conventionally known technique.

For example, the coating liquid for the heat-sensitive recording layer is coated on a support with an appropriate coating device such as an air knife coater, a blade coater, a bar coater, a gravure coater, a curtain coater, a short dwell coater, and a wire bar, and dried. Then, the recording layer can be formed.

Further, the coating amount of the coating liquid is not particularly limited, and generally 1.5 to 12 g / dry weight.
It is adjusted in the range of m ² , preferably 2.5 to 10 g / m ² .

As the support, paper, plastic sheet,
Synthetic paper, a composite sheet in which these are combined, a non-woven sheet, or a molded product is used.

If necessary, a protective layer (overcoat layer) made of resin or the like may be provided on the front surface and / or the back surface of the thermosensitive recording layer, or a single-layer or multi-layer pigment may be provided between the support and the thermosensitive recording layer. (For example, kaolin) or a synthetic resin (for example, plastic spherical particles, plastic spherical hollow particles) to provide an undercoat layer (undercoat layer), between the thermosensitive recording layer and the undercoat layer, or the thermosensitive recording layer and protection. It is of course possible to provide an intermediate layer composed of a pigment, a binder and the like between the layers, and further, various known techniques in the production method of the heat-sensitive recording material can be imparted, for example, the back surface of the support is subjected to an adhesive treatment. . Further, after forming the recording layer, super calendering treatment can be performed.

[0113]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples,% represents% by weight.

Production Example 1 [Production of zinc salt of 2- (4'-phenyloxybenzoyl) benzoic acid] 18.3 g of 2- (4'-phenyloxybenzoyl) benzoic acid
50 ml of an aqueous solution in which 2.4 g of 95% sodium hydroxide was dissolved was added dropwise to the methanol suspension solution (50 ml) of (1) at room temperature over 15 minutes, and the mixture was further stirred at room temperature for 2 hours. To the solution of 2- (4'-phenyloxybenzoyl) benzoic acid sodium salt, 100 ml of an aqueous solution in which 8.3 g of zinc sulfate heptahydrate was dissolved was added dropwise at room temperature over 30 minutes. After the dropping, the mixture was stirred for 1 hour, the precipitated solid was filtered, washed with water, and dried at 50 ° C. for 24 hours to obtain a colorless zinc salt of 2- (4′-phenyloxybenzoyl) benzoic acid 19. 6 g was obtained. Melting point 135-145 ° C

Production Example 2 [Production of zinc salt of 2- (4'-phenylthiobenzoyl) benzoic acid] In Example 1, 2- (4'-phenyloxybenzoyl)
2- (4'-phenylthiobenzoyl) instead of benzoic acid
A zinc salt of 2- (4′-phenylthiobenzoyl) benzoic acid was produced by a method similar to that described in Example 1 except that benzoic acid was used. Melting point 200-220 ° C

[Evaluation of Thermal Recording Paper] 1. Storage stability test of uncolored part The whiteness of the uncolored part (background) of each thermal recording paper prepared in the following Examples and Comparative Examples was measured by a color difference meter (Σ-8).
0, manufactured by Nippon Denshoku Co., Ltd.).

As the storage stability test, an oil resistance test and a writing instrument resistance test were conducted.

In the oil resistance test, each thermosensitive recording paper was overlaid with a capsule coated paper containing dioctyl phthalate, passed through a pressure roll, and stored at 25 ° C. for 1 week. It was measured using.

The larger the numerical value, the better the whiteness of the uncolored portion.

In the writing instrument resistance test, after writing with a fluorescent pen on the uncolored portion of each thermosensitive recording paper, the whiteness of the uncolored portion was visually observed after standing at 25 ° C. for 72 hours. ○ indicates a state with no stain and high whiteness, and × indicates a state in which it was stained black gray.

2. Storage stability test for color images Each thermal recording paper was loaded with a thermal paper color device (TH-P manufactured by Okura Electric Co., Ltd.
MD) was used to form a color image having a color density of 0.9 measured with a Macbeth densitometer (TR-524 type), and then a storage stability test was conducted.

As the storage stability test, a moist heat resistance test and an oil resistance test were carried out, and the residual ratio of the colored image on each thermosensitive recording paper after each test was examined.

The moist heat resistance test was carried out at 40 ° C. for each thermosensitive recording paper.
The color image density after storage for 24 hours in 90% relative humidity was measured using a Macbeth densitometer to determine the residual rate of the color image.

The oil resistance test was carried out by overlaying each thermosensitive recording paper with capsule coating paper containing dioctyl phthalate, passing it through a pressure roll, and storing it at 25 ° C. for 1 week. It was measured using a meter to determine the residual rate of the color image. Residual rate (%) = [(colored image density after each test) / colored image density before test (0.9)] × 100 The larger the value, the better the storage stability of the colored image. There is.

Examples 1 to 20 [Preparation of thermal recording paper]

[0126]

[Table 1]

[0127]

[Table 2]

[0128]

[Table 3]

The solutions A, B, and C were dispersed by a sand grinding mill so that the average particle diameter was 1.5 μm, to prepare dispersions.

Liquid A 100 g, liquid B 250 g, liquid C 250
g of the dispersion liquid and 23 g of 30% paraffin wax were mixed, and this was coated on a high-quality paper so that the dry coating amount was 5.0 g / m ^2, and dried to prepare a thermosensitive recording paper.

The compounds represented by the general formula (1) used as the electron-donating color-forming compound in the liquid A, the heat-fusible compound in the liquid C and the electron-accepting compound in the liquid B used in each example. Table 1 shows the benzoic acid derivatives or metal salts of the derivatives.

In Table 1, the heat-fusible compound a is 2-benzyloxynaphthalene, and the heat-fusible compound b is 1,2-
Bis (3'-methylphenoxy) ethane, thermofusible compound c is 4- (4'-methylphenoxy) biphenyl, and thermofusible compound d is oxalic acid di (4-methylbenzyl) ester. Represent

[0133]

[Table 4]

Examples 21 to 30 Thermal recording papers were produced in the same manner as in the above examples except that the following liquid D was used instead of liquid B.

[0135]

[Table 5]

The benzoic acid derivative represented by the general formula (1) used as the electron-donating color-forming compound in the liquid A, the heat-fusible compound in the liquid C and the electron-accepting compound in the liquid D used. Alternatively, the metal salt of the derivative is shown in Table 2.

In Table 2, the heat fusible compound a is 2-benzyloxynaphthalene, and the heat fusible compound b is 1,2-
Bis (3'-methylphenoxy) ethane, thermofusible compound c is 4- (4'-methylphenoxy) biphenyl, and thermofusible compound d is oxalic acid di (4-methylbenzyl) ester. Represent

[0138]

[Table 6]

Comparative Examples 1 to 5 Liquid A 100 g, liquid B 250 g, and liquid C 250 g dispersion were mixed with 30% paraffin wax 23 g, and the dry coating amount of this was 5.0 g / m ^2. To apply,
It was dried to prepare a heat sensitive recording paper. 2-Benzyloxynaphthalene was used as the heat-fusible compound in the liquid C.

The electron-donating color-forming compound in the liquid A and the electron-accepting compound in the liquid B used in each comparative example were the third compounds.
Shown in the table.

[0141]

[Table 7]

Tables 4 and 5 show Examples 1-30.
The results of the storage stability test of the uncolored part and the colored image of the thermosensitive recording paper prepared in Comparative Examples 1 to 6 are shown.

[0143]

[Table 8]

[0144]

[Table 9]

As is clear from the results shown in Tables 4 and 5, the heat-sensitive recording material containing the benzoic acid derivative represented by the general formula (1) or the metal salt of the derivative as the electron-accepting compound of the present invention. Is compared to conventional thermal recording materials,
Excellent storage stability of uncolored part and colored image.

[0146]

According to the present invention, it is possible to provide a heat-sensitive recording material which is excellent in storage stability of the uncolored portion and the color-developed image as compared with the conventional heat-sensitive recording material.

Continued Front Page (72) Inventor Masakatsu Nakatsuka 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd.

Claims (3)

[Claims] 1. A heat-sensitive recording material containing an electron-donating color-forming compound and an electron-accepting compound, wherein at least a benzoic acid derivative represented by the general formula (1) or a metal salt of the derivative is used as the electron-accepting compound. Thermal recording material containing one kind. [Chemical 1] (In the formula, X ₁ , X ₂ , X ₃ and X ₄ represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a nitro group, and Y ₁ and Y ₂ represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen. Represents an atom, and R ₁ represents an aryloxy group, an alkylthio group, an alkenylthio group or an arylthio group) 2. The heat-sensitive recording material according to claim 1, which contains at least one benzoic acid derivative represented by the general formula (1) or a metal salt of the derivative as an electron-accepting compound, and further contains a metal compound. 3. A metal salt of a benzoic acid derivative represented by the general formula (1). [Chemical 2] (In the formula, X ₁ , X ₂ , X ₃ and X ₄ represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a nitro group, and Y ₁ and Y ₂ represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen. Represents an atom, and R ₁ represents an aryloxy group, an alkylthio group, an alkenylthio group or an arylthio group)