JPH07149050A - Thermal recording body - Google Patents

Abstract

PURPOSE:To provide a thermal recording body in which the preserving property of a recording image and a blank paper part and recording sensitivity are excellent. CONSTITUTION:A thermal recording body is constituted by providing a recording layer containing colorless or light-colored basic dye and a developer on a supporting body. The developer consists of at least 4,4-bis(p-toluenesulfonyl aminocarbonylamino) diphenylmethane and zinc salt of 4-(3-(p- tolylsulfonyl)propyloxy) salicylic acid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material having excellent storability and recording sensitivity for recorded images and blank areas.

[0002]

2. Description of the Related Art Heretofore, a heat-sensitive recording material has been well known which uses a heat energy of a heat-sensitive head or the like to develop a colorless or light-colored basic dye and a color developer. Since such a thermal recording material is relatively inexpensive, and the recording device is compact and its maintenance is relatively easy, it is used not only as a recording medium for facsimiles and various computers but also in a wide range of fields such as thermal labels. .

In recent years, recording speeds of 10 seconds or less in A4 size for thermal fax and 120 characters / second or more for thermal printer have become possible, and there is a further demand for higher sensitivity of the thermal recording material. In addition, the use of heat-sensitive recording labels is increasing with the expansion of POS systems aimed at labor saving in the retail industry. However, since a phenol-based developer such as bisphenol A is used in an ordinary heat-sensitive recording material, a background fog may occur due to a solvent or the like,
It has a defect that the color-developing body undergoes discoloration due to oils and fats, chemicals and the like. Therefore, for example, when touching stationery and office supplies such as water-based pens, oil-based pens, fluorescent pens, vermillion flesh, adhesives, glues, diazo developers, etc., the white part is colored, or the density of the recorded image is significantly reduced. , And the product value was significantly impaired due to discoloration.

Various methods such as a method of providing a protective layer on the recording layer and a method of adding a storability improver to the recording layer have been proposed for the purpose of improving such defects, but each of them has new defects. However, there is a strong demand for further improvement because the effect is not always satisfactory.

[0005]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a thermosensitive recording medium in which the background fogging due to the influence of temperature and humidity is small and the recorded image does not easily fade even when influenced by oils and fats, solvents or plasticizers. To provide.

[0006]

SUMMARY OF THE INVENTION The present invention comprises:
In a heat-sensitive recording material provided with a recording layer containing a colorless or light-colored basic dye and a developer, the developer is at least 4,4'-bis (p-toluenesulfonylaminocarbonylamino) diphenylmethane and 4- [ A thermosensitive recording medium comprising a zinc salt of 3- (p-tolylsulfonyl) propyloxy] salicylic acid.

[0007]

The heat-sensitive recording material using 4,4'-bis (p-toluenesulfonylaminocarbonylamino) diphenylmethane as a color developer is excellent in oil resistance and plasticizer resistance of a color image, but has a drawback that recording sensitivity is low. was there. Conventionally,
Waxes having a melting point of 40 to 100 ° C. are used as a carrier (JP-A-48-19231), or a fatty acid amide and a petroleum wax are combined (JP-B-51).
No. 27599), it has been proposed to increase the sensitivity.

However, although these methods have some effect on the improvement of sensitivity,
In combination with 4,4′-bis (p-toluenesulfonylaminocarbonylamino) diphenylmethane, there was a problem that the storage stability of the background, especially the background fogging easily caused by contact with humidity or a plasticizer. Therefore, as a result of intensive studies on the improvement of the sensitivity by the present inventors, the combined use of the zinc salt of 4- [3- (p-tolylsulfonyl) propyloxy] salicylic acid with the above-mentioned color developer reduces the whiteness. However, they found that the recording sensitivity and the recording density were improved, and completed the present invention.

Thus, in the present invention, 4,4'-bis (p-toluenesulfonylaminocarbonylamino) diphenylmethane and 4- [3- (p-tolylsulfonyl)
The proportion of the zinc salt of propyloxy] salicylic acid is not particularly limited, but 4,4′-bis (p
1 to 200 parts by weight, preferably 10 to 100 parts by weight of zinc salt of 4- [3- (p-tolylsulfonyl) propyloxy] salicylic acid, relative to 100 parts by weight of -toluenesulfonylaminocarbonylamino) diphenylmethane. It is desirable to adjust.

As a method for producing the zinc salt of 4- [3- (p-tolylsulfonyl) propyloxy] salicylic acid, for example, in a water or a mixed medium of water and an organic solvent
A method of reacting an alkali metal salt of [3- (p-tolylsulfonyl) propyloxy] salicylic acid with a zinc compound, 4- [3- (p-tolylsulfonyl) propyloxy] salicylic acid, and a wet simultaneous grinding of a zinc compound It can be manufactured by a method such as.

The former method has some drawbacks in operability during production, but is advantageous in terms of the yield and purity of zinc chloride. On the other hand, the latter method has some drawbacks in terms of the yield and purity of zinc chloride, but has the advantage that a composite zinc salt can be produced very easily.

The organic solvent used in the above-mentioned production method is preferably one having a low solubility in water and a high solubility of the zinc salt of the aromatic carboxylic acid formed, for example, an aromatic compound, a halide or an ester. A compound etc. are mentioned. Further, specific organic solvents include toluene, xylene, trichlene, ethyl acetate and the like.

Examples of the zinc compound for preparing the zinc salt include zinc oxide, zinc hydroxide, zinc carbonate, zinc sulfate and zinc chloride. Of these, zinc sulfate and zinc chloride are particularly preferably used. To be done. Although the amount of the zinc compound used is not particularly limited,
It is desirable to use the same amount as that of-[3- (p-tolylsulfonyl) propyloxy] salicylic acid.

In the present invention, as the colorless or light-colored basic dye contained in the heat-sensitive recording layer, known colorless or light-colored basic dyes can be used. Specifically, for example, tris (4-dimethylaminophenyl) methane, 3,
3-bis (p-dimethylaminophenyl) phthalide,
3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (p-dimethylaminophenyl) -3- (4-diethylamino-2-methylphenyl) -6-dimethylaminophthalide, 3- (p-dimethylaminophenyl) -3- (1-methylpyrrole-3-
Yl) -6-dimethylaminophthalide, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-n-butyl-2-methylindole-3-) Yl) phthalide, 3,3-bis (1-n-
Amyl-2-methylindol-3-yl) phthalide,
3,3-bis (2-phenylindol-3-yl)-
6-dimethylaminophthalide, 3,3-bis (1,2-
Dimethylindol-3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3- (p
-Dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-methylindole-3-
Il) phthalide,

3- (p-dimethylaminophenyl) -3
-(1-Ethyl-2-methylindol-3-yl) phthalide, 3,3-bis (4-diethylamino-2-ethoxyphenyl) -4-azaphthalide, 3- (p-diethylamino-o-methylphenyl)- 3- (1-ethyl-
2-Methylindol-3-yl) -4-azaphthalide, 3- (p-diethylamino-o-methylphenyl)
-3- (2-phenyl-1-methylindol-3-yl) -4-azaphthalide, 3- (p-diethylamino-
o-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3-
(P-Diethylamino-on-hexyloxyphenyl) -3- (1-ethyl-2-methylindole-3-
Yl) -4-azaphthalide, 3- (p-diethylamino-o-ethoxyphenyl) -3- (2-methyl-1-n)
-Octylindol-3-yl) -4-azaphthalide, 3- (p-dibenzylaminophenyl) -3-
(1,2-Dimethylindol-3-yl) -7-azaphthalide, 3- (p-diethylamino-o-ethoxyphenyl) -3- (1-ethyl-2-methylindole-
3-yl) -7-azaphthalide,

1,1-bis [p- (N-methyl-N-phenyl) anilino] -1- (9-n-butylcarbazol-3-yl) methane, 3,3-bis (9-ethylcarbazole- 3-yl) -6-dimethylaminophthalide,
N-butyl-3- {bis [4- (N-methylanilino)
Phenyl] methyl} carbazole, 3,3-bis [1-
(4-Methoxyphenyl) -1- (4-dimethylaminophenyl) ethylene-2-yl] -4,5,6,7-tetrachlorophthalide, 3,3-bis [1- (4-methoxyphenyl) -1- (4-Pyrrolidinophenyl) ethylene-2-yl] -4,5,6,7-tetrachlorophthalide, 3,3-bis [1,1-bis (4-pyrrolidinophenyl) ethylene- 2-yl] -4,5,6,7-tetrabromophthalide, 3,6-bis (dimethylamino) fluorene-9-spiro-3 '-(6'-dimethylamino)
Phthalide, [4,4'-bis (dimethylamino) benzhydryl] benzyl ether, N-halophenyl-leuco auramine, N-2,4,5-trichlorophenyl leuco auramine, 4,4'-bis (dimethylamino) Benzhydryl-p-toluenesulfinic acid ester,
3,7-bis (diethylamino) -10-benzoylphenoxazine, 3,7-bis (dimethylamino) -1
0-benzoylphenoxazine, p-nitrobenzoylleucomethylene blue, 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3
-Phenyl-spiro-dinaphthopyran, 3-benzyl-
Spiro-dinaphthopyran, 3-methyl-naphtho (6'-
(Methoxybenzo) spiropyran, 3-propyl-spiro-dibenzopyran, di-β-naphthospiropyran, 3-
Methyl-di-β-naphthospiropyran, rhodamine-B
-Anilinolactam, rhodamine (p-nitroanilino) lactam, rhodamine (o-chloroanilino) lactam, 3,6-dimethoxyfluorane, 3-dimethylamino-6-methoxyfluorane, 3-dimethylamino-
7-Methoxyfluorane, 3-diethylamino-6-methylfluorane, 3-diethylamino-6-methoxyfluorane, 3-diethylamino-7-methoxyfluorane, 3-diethylamino-7-chlorofluorane, 3-
Diethylamino-7-phenylfluorane, 3-diethylamino-7-aminofluorane, 3-diethylamino-7-diethylaminofluorane,

3-diethylamino-7-cyclohexylaminofluorane, 3-diethylamino-7- (N-methylamino) fluorane, 3-diethylamino-7-
(N-acetyl-N-methylamino) fluorane, 3-
Diethylamino-7- (N-β-chloroethyl-N-methylamino) fluorane, 3-diethylamino-7-anilinofluorane, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-7-bis (dimethyl) Benzyl) aminofluorane, 3-diethylamino-7- (N-methyl-N-benzylamino) fluorane, 3-diethylamino-7- (N-cyclohexyl-N-benzylamino) fluorane, 3-diethylamino-7- (o -Chloroanilino) fluorane, 3-diethylamino-7- (o-fluoroanilino) fluorane, 3-cyclohexylamino-7-methylfluorane, 3-cyclohexylamino-6-chlorofluorane, 3-pyrrolidino-7-cyclohexylamino Fluoran, 3-benzylami 6-chloro-full Oran, 3
-Diphenylamino-6-diphenylaminofluorane, 3- (N-ethyl-p-toluidino) -6-methylfluorane, 3- (N-ethyl-p-toluidino) -7
-Methylfluorane, 3- (N-ethyl-p-toluidino) -7- (N-phenyl-N-methylamino) fluorane, 3- (N-ethyl-Nn-hexylamino)-
7-anilinofluorane, 3-di (n-butylamino)
-7- (o-chloroanilino) fluorane, 3-di (n
-Butylamino) -7- (o-fluoroanilino) fluorane, 3- (N-ethyl-N-isoamylamino)-
7- (o-chloroanilino) fluorane, 3- (Nn)
-Hexyl-N-ethylamino) -7- (o-chloroanilino) fluorane, 3-dimethylamino-7- [m-
(Trifluoromethyl) anilino] fluorane, 3-diethylamino-7- [m- (trifluoromethyl) anilino] fluorane, 3-diethylamino-7- (2-carbomethoxy-anilino) fluorane, 4-amino-8
-Diethylaminobenzo [a] fluorane, 4-benzylamino-8-diethylaminobenzo [a] fluorane, 2-mesidino-8-diethylamino-benz [C]
Fluorane, 3-diethylamino-7,8-benzofluorane, 3- (N-ethyl-N-isoamylamino)-
7,8-Benzofluorane, 3-dimethylamino-6-
Methyl-7-anilinofluorane, 3-diethylamino-6,7-dimethylfluorane, 3-diethylamino-
6,8-Dimethylfluorane, 3-diethylamino-5
-Methyl-7-dibenzylaminofluorane, 3-diethylamino-5-methyl-7-t-butylfluorane,
3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6-methyl-7-alkyl (C8-10) aminofluorane, 3-diethylamino-
6-chloro-7-anilinofluorane, 3-diethylamino-6-methyl-7- (2,4-xylidino) fluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6 -Methyl-7-m
-Toluidinofluorane, 3-diethylamino-6-methyl-7- (p-ethoxyanilino) fluorane, 3-
Diethylamino-6-methoxy-7-anilinofluorane, 3-di (n-butylamino) -6-methoxy-7-
Anilinofluorane, 3-di (n-butylamino) -6
-Methyl-7-bromofluorane, 3-di (n-butylamino) -6-methyl-7-anilinofluorane, 3-
(N-Ethyl-N-ethoxypropylamino) -6-methyl-7-anilinofluorane, 3-di (n-butylamino) -6-methyl-7- (p-fluoroanilino) fluorane, 3- Di (n-butylamino) -6-methyl-
7- (p-chloroanilino) fluorane, 3-di (n-
Butylamino) -6-methyl-7-m-toluidinofluorane, 3-di (n-pentylamino) -6-methyl-
7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-pn -Butylanilinofluorane, 3-pyrrolidino-6-methyl-7-p-toluidinofluorane, 3- (4-n-butylaminoanilino) -6-methyl-7-chlorofluorane, 3- [4- (4-anilinoanilino) anilino] -6-methyl-7-chlorofluorane, 3- [4- (4-dimethylaminoanilino) anilino] -6-methyl-7-chlorofluorane, 3- [ Four
-(4-Dimethylaminoanilino) anilino] -6-methylfluorane,

8-diethylamino-benzo [a] fluorane, 8- [4- (4-dimethylaminoanilino) anilino] benzo [a] fluorane, 3- (N-methyl-N)
-N-propylamino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-N-isobutylamino)
-6-Methyl-7-anilinofluorane, 3- (N-ethyl-N-cyclopentylamino) -6-methyl-7-
Anilinofluorane, 3- (N-cyclohexyl-N-
Methylamino) -6-methyl-7-anilinofluorane, 3- (Nn-butyl-N-cyclohexylamino) -6-methyl-7-anilinofluorane, 3- (N
-Ethyl-p-toluidino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-p-toluidino)-
6-methyl-7- (p-toluidino) fluorane, 3-
(N-methyl-Nn-amylamino) -6-methyl-
7-anilinofluorane, 3- (N-ethyl-Nn-)
Amylamino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-N-isoamylamino) -6-
Methyl-7-anilinofluorane, 3- (N-methyl-
N-n-hexylamino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-Nn-hexylamino) -6-methyl-7-anilinofluorane, 3- (N
-Ethyl-N-β-ethylhexylamino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-N-
2-Tetrahydrofurfurylamino) -6-methyl-7
-Anilinofluorane, 3- [N- (3-ethoxypropyl) -N-methylamino] -6-methyl-7-anilinofluorane, 2,2-bis {4- [6 '-(N- Examples thereof include compounds such as cyclohexyl-N-methylamino) -3′-methylspiro (phthalide-3,9′-xanthene) -2′-ylamino] phenyl} propane, and it is possible to use two or more of these in combination. is there.

The use ratio of the basic dye and the color developer contained in the recording layer is not particularly limited, but is generally 0.5 to 1 part by weight of the basic dye.
It is desirable to use about 50 parts by weight, preferably about 1 to 10 parts by weight of the developer.

In the present invention, 4,4'-bis (p-toluenesulfonylaminocarbonylamino) diphenylmethane and 4- [3- (p-tolylsulfonyl) are used as developers.
It is characterized by using a zinc salt of propyloxy] salicylic acid, but it is also possible to use the following publicly known developers in combination as long as the effects of the present invention are not impaired.

Inorganic acidic substances such as activated clay, attapulgite, colloidal silica, aluminum silicate, 4-cumylphenol, hydroquinone monobenzyl ether,
4,4'-isopropylidenediphenol, 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,
4'-dihydroxydiphenyl-2,2-butane, 4,
4'-dihydroxydiphenylmethane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane,
2,2-bis (4-hydroxyphenyl) heptane, bis (4-hydroxyphenylthioethoxy) methane,
1,5-di (4-hydroxyphenylthio) -3-oxapentane, 1,1-bis (4-hydroxyphenyl)
-1-phenylethane, 1,4-bis [α-methyl-α
-(4'-hydroxyphenyl) ethyl] benzene,
1,3-bis [α-methyl-α- (4′-hydroxyphenyl) ethyl] benzene, 4,4′-dihydroxydiphenyl sulfide, di (4-hydroxy-3-methylphenyl) sulfine, 4-hydroxy-4 ′ -Methyldiphenylsulfone, 4-hydroxy-4′-isopropoxydiphenylsulfone, 2,4′-dihydroxydiphenylsulfone, 4,4′-dihydroxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 4 -Hydroxyphenyl-4'-benzyloxyphenyl sulfone, 4-hydroxy-3 ',
4'-tetramethylene biphenyl sulfone, 3,4-dihydroxyphenyl-p-tolyl sulfone, 4,4'-
Dihydroxybenzophenone, benzyl 4-hydroxybenzoate, butyl bis (p-hydroxyphenyl) acetate, methyl bis (p-hydroxyphenyl) acetate, (4
-Hydroxyphenylthio) acetic acid-2- (4-hydroxyphenylthio) ethyl ester, di (p-hydroxyphenylthioethyl) ether, N, N'-di-m-chlorophenylthiourea, N- (phenoxyethyl)- Four
-Phenolic compounds such as hydroxyphenyl sulfonamide, 4- [2- (p-methoxyphenoxy) ethyloxy] salicylic acid, 5- [p- (2-p-methoxyphenoxyethoxy) cumyl] salicylic acid, p-chlorobenzoic acid, etc. Aromatic carboxylic acids, salts of these aromatic carboxylic acids with polyvalent metals such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin and nickel, and organic acid substances such as antipyrine complexes of zinc thiocyanate Etc. are illustrated.

In the present invention, a sensitizer may be added to the recording layer if necessary. Specific examples of the sensitizer in that case include, for example, stearic acid amide, methoxycarbonyl-N-stearic acid benzamide, N-benzoylstearic acid amide, N-eicosanoic acid amide,
Ethylenebistearic acid amide, behenic acid amide, methylenebisstearic acid amide, N-methylolstearic acid amide, dibenzyl terephthalate, dimethyl terephthalate, dioctyl terephthalate, benzyl p-benzyloxybenzoate, 1-hydroxy-2-naphthoate. Phenyl acid salt, dibenzyl oxalate, oxalate-di-p-methylbenzyl, oxalate-di-p-chlorobenzyl, 2-
Naphthyl benzyl ether, m-terphenyl, p-benzyl biphenyl, biphenyl-p-tolyl ether,
Di (p-methoxyphenoxyethyl) ether, 1,2
-Di (3-methylphenoxy) ethane, 1,2-di (4
-Methylphenoxy) ethane, 1,2-di (4-methoxyphenoxy) ethane, 1,2-di (4-chlorophenoxy) ethane, 1,2-diphenoxyethane, 1- (4
-Methoxyphenoxy) -2- (2-methylphenoxy) ethane, p-methylthiophenylbenzyl ether, 1,4-di (phenylthio) butane, p-acetotoluidide, p-acetophenetide, N-acetoacetyl-p- Toluidine, di (β-biphenylethoxy) benzene, p-di (vinyloxyethoxy) benzene,
Examples include 4,4′-dihydroxydiphenyl sulfone, 1-isopropylphenyl-2-phenylethane and the like. The amount of these sensitizers used is not particularly limited, but it is generally desirable to adjust the amount within a range of about 5 to 500 parts by weight with respect to 100 parts by weight of the color developer.

Further, in order to suppress the background fog caused by heat, tetrakis (1,2,2,6,6-pentamethyl-4
It is desirable to use a hindered amine stabilizer such as -piperidinyl) -1,2,3,4-butanetetracarboxylate together. Further, as long as the effect of the present invention is not impaired, a preservative improving agent can be used in combination, if necessary, in order to further enhance the preservability of the recorded image. Specific examples of such storage improvers include 1,4-diglycidyloxybenzene, 4,4′-diglycidyloxydiphenyl sulfone, 4-benzyloxy-4 ′-(2-methyl-2,3-epoxy). Propyloxy) diphenyl sulfone, diglucidyl terephthalate, bisphenol A
Type epoxy compounds such as epoxy resin, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-te)
rt-butylphenol), 2,2'-ethylidene bis (4,6-di-tert-butylphenol), 4,
4'-thiobis (3-methyl-6-tert-butylphenol), 4,4'-thiobis (2-methyl-6-t
ert-butylphenol), 4,4'-butylidene bis (6-tert-butyl-m-cresol), 1,1,3
-Tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 4,4'-thiobis ( 3-methylphenol),
4,4'-dihydroxy-3,3 ', 5,5'-tetrabromodiphenyl sulfone, 4,4'-dihydroxy-
3,3 ′, 5,5′-tetramethyldiphenyl sulfone, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-)
Hindered phenol compounds such as 3,5-dichlorophenyl) propane and 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1- [α-methyl-α- (4′-hydroxyphenyl) ethyl ] -4-
[Α ', α'-bis (4 "-hydroxyphenyl) ethyl] benzene, N, N'-di-2-naphthyl-p-phenylenediamine, 2,2'-methylenebis (4,6-di-tert- Butylphenyl) sodium phosphate and the like.

In order to prepare a coating liquid for a recording layer containing these substances, water is generally used as a dispersion medium, a basic mill, a developer, a developer, a ball mill, an attritor, a sand mill and the like are used. Further, a coating solution can be obtained by dispersing and preparing a sensitizer and the like which are added as necessary together / or separately. In such a coating solution, as an adhesive, starch, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, arabic gum, polyvinyl alcohol, diisobutylene / maleic anhydride copolymer salt, styrene / maleic anhydride copolymer salt. , Ethylene / acrylic acid copolymer salt,
The styrene / acrylic acid copolymer salt, the styrene / butadiene copolymer emulsion and the like are adjusted in the range of 10 to 40% by weight, preferably 15 to 30% by weight of the total solid content.

It is also possible to use various pigments in combination in the coating solution. For example, kaolin, clay, calcium carbonate, calcined clay, calcined kaolin, titanium oxide, diatomaceous earth, fine anhydrous silica, activated clay, and other inorganic materials. Examples thereof include pigments, styrene microballs, nylon powder, polyethylene powder, urea / formalin resin filler, and organic pigments such as raw starch particles.

Further, various auxiliary agents such as sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium lauryl alcohol sulfate / sodium salt, alginate, fatty acid metal salt and the like, and benzophenone-based agents are contained in the coating solution. , A triazole-based ultraviolet absorber, other defoaming agents, fluorescent dyes, coloring dyes and the like can be appropriately added.

In the present invention, the method of forming the heat-sensitive recording layer is not particularly limited, and the heat-sensitive recording layer can be formed according to a conventionally known and commonly used technique. For example, air knife coater, variber blade coater, pure blade coater, short dwell coater,
It can be formed by coating the coating solution on a support with a curtain coater or the like and drying. Also, there are no particular limitation on the coating amount, 2~12g / m ² in weight after drying, it is preferably adjusted in the range of 3 to 10 g / m ^2. As the support, paper, synthetic paper, plastic film or the like is appropriately selected and used.

If necessary, on the thermal recording material and / or
Alternatively, by providing a resin layer on the back surface of the recording medium,
Furthermore, it is possible to enhance the storage stability of the recorded image. Further, an undercoat layer may be provided on the support to improve image quality and sensitivity, an adhesive label may be applied to the back surface of the recording material to form an adhesive label, or a magnetic layer may be provided on the back surface of the recording material to form a thermosensitive recording material. Various known techniques in the manufacturing field can be applied. Further, the image quality and the image density can be improved by performing a super calendering process after forming the recording layer.

[0029]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Unless otherwise specified, "part" and "%" in the examples are
"Part by weight" and "% by weight" are shown, respectively.

Example 1 Preparation of Solution A 10 parts of 3-di (n-butylamino) -6-methyl-7-anilinofluorane, 5% aqueous solution of methylcellulose 5
Parts and 40 parts of water were pulverized with a sand mill until the average particle size became 1.5 μm.

Preparation of Solution B A composition comprising 30 parts of 4,4′-bis (p-toluenesulfonylaminocarbonylamino) diphenylmethane, 5 parts of a 5% aqueous solution of methylcellulose, and 80 parts of water having an average particle diameter of 1. It was pulverized until it became 0 μm or less.

Preparation of Solution C 4- [3- (p-tolylsulfonyl) propyloxy]
A composition consisting of 30 parts of a zinc salt of salicylic acid, 5 parts of a 5% aqueous solution of methylcellulose, and 80 parts of water was ground by a sand mill until the average particle size became 1.5 μm.

Preparation of Solution D A composition comprising 20 parts of 1,2-di (3-methylphenoxy) ethane, 5 parts of a 5% aqueous solution of methyl cellulose, and 55 parts of water was sand-milled until the average particle size reached 1.5 μm. Crushed.

Formation of Recording Layer 55 parts of solution A, 80 parts of solution B, 35 parts of solution C, 80 parts of solution D, 1
A recording layer coating solution obtained by mixing and stirring 160 parts of a 0% polyvinyl alcohol aqueous solution and 25 parts of clay (trade name: HG Clay / manufactured by Huber) was dried on one surface of a fine paper of 45 g / m ² and dried. The recording layer was formed by coating and drying so that the coating amount was 4 g / m ² .

Example 2 In the preparation of solution A in Example 1, 3- (N-ethyl-N- instead of 10 parts of 3-di (n-butylamino) -6-methyl-7-anilinofluorane was used. A thermosensitive recording medium was obtained in the same manner as in Example 1 except that 10 parts of ethoxypropylamino) -6-methyl-7-anilinofluorane was used.

Example 3 In the preparation of solution A of Example 1, 3-di (n-butylamino) was used instead of 10 parts of 3-di (n-butylamino) -6-methyl-7-anilinofluorane. A thermosensitive recording medium was obtained in the same manner as in Example 1 except that 10 parts of -7- (o-chloroanilino) fluorane was used.

Example 4 Instead of 20 parts of 1,2-di (3-methylphenoxy) ethane in the preparation of solution D of Example 1, di-p oxalate was used.
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that 20 parts of methylbenzyl ester was used.

Example 5 Instead of the liquid D of Example 1, 80 parts of a 21.5% stearic acid amide emulsion liquid (trade name: G-270 / produced by Chukyo Yushi Co., Ltd., average particle size = 0.4 μm) was used. A thermal recording material was obtained in the same manner as in Example 1 except that the thermal recording material was used.

Example 6 In the preparation of solution D of Example 1, instead of 20 parts of 1,2-di (3-methylphenoxy) ethane, biphenyl-p was used.
A thermal recording material was obtained in the same manner as in Example 1 except that 20 parts of tolyl ether was used.

Example 7 In the same manner as in Example 1 except that 20 parts of p-benzylbiphenyl was used in place of 20 parts of 1,2-di (3-methylphenoxy) ethane in the preparation of the liquid D of Example 1. A thermosensitive recording material was obtained.

Example 8 The same as Example 1 except that 20 parts of 2-naphthylbenzyl ether was used in place of 20 parts of 1,2-di (3-methylphenoxy) ethane in the preparation of the liquid D of Example 1. A thermosensitive recording medium was obtained.

Example 9 Formation of Recording Layer 55 parts of solution A, 35 parts of solution B, 80 parts of solution C, 80 parts of solution D, 1
A recording layer coating solution obtained by mixing and stirring 160 parts of 0% polyvinyl alcohol aqueous solution and 25 parts of clay (trade name: HG Clay / manufactured by Huber) was dried on one surface of a fine paper of 45 g / m ² and dried. A recording layer was formed by coating and drying so that the coating amount was 4 g / m ² .

Example 10 Preparation of Solution E Tetrakis (1,2,2,6,6-pentamethyl-4-)
Piperidinyl) -1,2,3,4-butanetetracarboxylate 10 parts, 5% aqueous solution of methylcellulose 5
Parts and 40 parts of water were pulverized with a sand mill until the average particle size became 1.5 μm.

Formation of Recording Layer 55 parts of solution A, 80 parts of solution B, 35 parts of solution C, 80 parts of solution D, E
Liquid 10 parts, 10% polyvinyl alcohol aqueous solution 160
And 25 parts of clay (trade name: HG Clay / manufactured by Huber) are mixed and stirred to obtain 45
coating amount after drying on one surface of woodfree paper g / m ² is 4g / m ²
Was applied and dried to form a recording layer.

Example 11 Preparation of Solution F Consisting of 10 parts of 4-benzyloxy-4 ′-(2-methyl-2,3-epoxypropyloxy) diphenylsulfone, 5 parts of a 5% aqueous solution of methylcellulose, and 40 parts of water. The composition was ground with a sand mill until the average particle size was 1.5 μm.

Formation of Recording Layer 55 parts of solution A, 80 parts of solution B, 35 parts of solution C, 80 parts of solution D, F
Liquid 55 parts, 10% polyvinyl alcohol aqueous solution 160
Of 25 parts and 25 parts of calcium carbonate mixed and stirred
45g / m layer coating solution²After drying on one side of fine paper
Coating amount is 4g / m ²Coating and dry the recording layer
Formed.

Example 12 Preparation of liquid G A composition consisting of 100 parts of calcined clay (trade name: manufactured by Ansilex / EMC, oil absorption = 110 ml / 100 g), 100 parts of 10% aqueous solution of polyvinyl alcohol, and 200 parts of water was prepared. By mixing and stirring, a coating liquid for the undercoat layer was obtained.

[0048] one surface of woodfree paper of Preparation 45 g / m ² of the heat-sensitive recording material, after coating and drying the solution G so that the coating amount after drying of 8 g / m ^2, recording was prepared in the same manner as in Example 1 Coating amount after layer coating is 4g /
After coating and drying so as to be m ² , a super calender treatment was carried out to obtain a thermosensitive recording material.

Comparative Example 1 Zinc salt of 4- [3- (p-tolylsulfonyl) propyloxy] salicylic acid was used in the preparation of solution C of Example 1.
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that 30 parts of 4,4'-isopropylidenediphenol was used instead of parts.

Comparative Example 2 In the preparation of solution C of Example 1, zinc salt of 4- [3- (p-tolylsulfonyl) propyloxy] salicylic acid 30 was used.
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that 30 parts of 4-hydroxy-4′-isopropoxydiphenyl sulfone was used in place of the parts.

Comparative Example 3 In the preparation of the liquid B of Example 1, 30 parts of 4,4'-isopropylidenediphenol was used instead of 30 parts of 4,4'-bis (p-toluenesulfonylaminocarbonylamino) diphenylmethane. A thermal recording material was obtained in the same manner as in Example 1 except for the above.

Comparative Example 4 In the formation of the recording layer of Example 1, 80 parts of solution B and 3 parts of solution C were used.
Example 1 except that 115 parts of solution B was used instead of 5 parts.
A thermosensitive recording medium was obtained in the same manner as described above.

Comparative Example 5 In the formation of the recording layer of Example 1, 80 parts of solution B and 3 parts of solution C were used.
Example 1 except that 115 parts of C liquid were used instead of 5 parts.
A thermosensitive recording medium was obtained in the same manner as described above.

Comparative Example 6 In the formation of the recording layer of Comparative Example 1, 80 parts of solution B and 35 parts of solution C were used.
A thermosensitive recording medium was obtained in the same manner as in Comparative Example 1 except that 115 parts of C liquid was used instead of parts. The 18 types of thermal recording materials thus obtained were subjected to the following evaluation tests, and the results are shown in Table 1.

[Whiteness] In order to evaluate the degree of color fog, the whiteness of the recording layer was measured with a Hunter whiteness meter.

[Color density] Thermal recording medium evaluation machine (trade name:
TH-PMD / Okura Electric Co., Ltd.) and applied voltage 24
Each thermosensitive recording medium was colored at V and a pulse time of 2 ms, and the color density of the obtained recorded image was measured by a Macbeth densitometer (RD-91).
4 type / manufactured by Macbeth Co., Ltd.] in visual mode.

[Oil resistance] The edible oil was dropped on the heat-sensitive recording body on which the color was printed, and the state of the print was visually evaluated after standing for 24 hours.

[Solvent Resistance] A yellow oil-based magic ink was used to write on a heat-sensitive recording material on which color was printed, and the state of printing after that was visually evaluated.

[Plasticizer resistance] polypropylene pipe (4
A vinyl chloride wrap film (manufactured by Mitsui Toatsu Chemicals Co., Ltd.) is wound in three layers on a 0 mmφ tube, and a heat-sensitive recording material, which is partially printed and colored, is sandwiched so that the printed and colored surface is on the outside, and further on top. The vinyl chloride wrap film was wrapped in three layers, and the plasticizer resistance was evaluated from the print density after leaving it at 30 ° C. for 24 hours and the whiteness of the blank area.

[Heat Resistance] As a background fogging acceleration test, a heat-sensitive recording material before printing was treated under a drying condition of 60 ° C. for 24 hours, and then the degree of fogging was visually evaluated.

[Humidity resistance] The heat-sensitive recording material before printing is
After processing for 24 hours under the condition of 75% RH, the degree of fogging was visually evaluated.

[Light resistance] A heat-sensitive recording material on which printing color is formed is
It was exposed to direct sunlight for 2 days, and the color density of the recorded image was measured by a Macbeth densitometer (RD-914 type / manufactured by Macbeth Co.) in a visual mode.

[Evaluation Criteria] Evaluation criteria for oil resistance, solvent resistance, plasticizer resistance, heat resistance and humidity resistance are as follows.

[0064]

[Table 1]

[0065]

As is clear from the results shown in Table 1, the heat-sensitive recording materials of the present invention are excellent in storability of recorded images, particularly oil resistance, plasticizer resistance and solvent resistance, and have excellent recording sensitivity. Was also an excellent thermal recording material.

Claims (1)

[Claims] 1. A thermosensitive recording medium comprising a support and a recording layer containing a colorless or light-colored basic dye and a developer, wherein the developer is at least 4,4'-bis (p-toluene). A heat-sensitive recording material comprising a sulfonylaminocarbonylamino) diphenylmethane and a zinc salt of 4- [3- (p-tolylsulfonyl) propyloxy] salicylic acid.