JPH0672037A - Thermal recording sheet - Google Patents

Abstract

PURPOSE:To improve plasticizer resistance by adding special polyvalent hydroxy aromatic compound and bisphenol A type epoxy resin to a heat sensitive color developing layer having basic colorless dye and organic developer as stabilizers. CONSTITUTION:A color developing layer contains polyvalent hydroxy aromatic compound represented by a formula I such as stearyl gallate and bisphenol A type epoxy resin represented by a formula II. However, in the formula I, R is 18-35C aryl group, and formulae III-VII. In the formulae III-VII, R is 18-35 alkyl group. n is 2 or 3, X is -CH2-, -CO2-, -CO-, -O-, -CONH-. In the formula VIII (R<1> is 18-35C alkyl group), -SO2-, -SO3 or -SO2NH-. In the formula II, n is 1-20. Triphenyl methane series are used as the basic colorless dye, and bisphenol A types are used as the organic developer.

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 sheet which prevents bleeding of a recorded image due to a plasticizer.

[0002]

2. Description of the Related Art Generally, a heat-sensitive recording sheet is usually prepared by grinding and dispersing a colorless or light-colored basic colorless dye and an organic developer such as a phenolic substance into fine particles, and then mixing them together to prepare a binder and a filler. A coating solution obtained by adding agents, sensitivity enhancers, lubricants and other auxiliaries to a support such as paper, synthetic paper, film, plastic, etc., such as a hot pen, thermal head, hot stamp, laser light. Color recording is obtained by an instant chemical reaction by heating such as.

These thermal recording sheets are used for measuring recorders, computer terminal printers, facsimiles,
It has been applied to a wide range of fields such as automatic ticket vending machines and bar code labels, but recently, with the diversification and high performance of these recording devices, the quality requirements for thermal recording sheets have become higher. . For example, as recording speed increases, it is required to obtain a clear color image with high density even with a small amount of heat energy, and light resistance on the other hand,
There is a demand for a heat-sensitive recording sheet having excellent storage stability such as weather resistance and oil resistance.

As a conventional example of a heat-sensitive recording sheet, for example, Japanese Patent Publication No. 43-4160 or Japanese Patent Publication No. 45-1403.
The heat-sensitive recording material disclosed in Japanese Patent No. 9 is mentioned, but such a conventional heat-sensitive recording material has a low thermal response, for example, and sufficient color density cannot be obtained during high-speed recording.

As a method for improving such a defect, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane is used as a leuco dye (JP-A-49-109120), 3- Dibutylamino-
Development of high-sensitivity dyes such as using 6-methyl-7-anilinofluorane (JP-A-59-190891) has been made, and a substance having a good coloring property as a developer 1,7-
Bis (4-hydroxyphenylthio) -3,5-dioxaheptane (JP-A-59-106456), 1,
By using 5-bis (4-hydroxyphenylthio) -3-oxaheptane (JP-A-59-116262) and 4-hydroxy-4'-isopropoxydiphenyl sulfone (JP-B-63-46067). Techniques for achieving high speed and high sensitivity have been disclosed.

[0006]

However, these heat-sensitive recording sheets have remarkably poor storage stability of the recorded images, so that when they are printed by a bar code printer, the color-developed image is a wrap of vinyl chloride film or the like. When it comes into contact with a plasticizer (DOP, DOA, etc.) contained in the film, there is a problem that the image density is remarkably reduced or bleeding, and as a result, reading by a bar code reader is hindered.

An object of the present invention is to provide a heat-sensitive recording sheet which has high sensitivity and prevents discoloration and bleeding of an image due to a plasticizer.

[0008]

The present invention is directed to a specific polyvalent hydroxyaromatic compound represented by the general formula (I) and a bisphenol A type epoxy resin represented by the formula (II) as a stabilizer in a thermosensitive coloring layer. By containing the above, the above problems are solved all at once.

[0009]

[Chemical 3]

[Chemical 4]

In the present invention, the polyhydric hydroxyaromatic compound used as the stabilizer, in other words, the polyhydric phenol derivative can be exemplified by the following, but not limited thereto.

[0011]

[Chemical 5]

[Chemical 6]

[Chemical 7]

Of the above polyvalent hydroxyaromatic compounds,
Stearyl gallate is the best in terms of quality and performance.

The softening point of the bisphenol A type epoxy resin used in the present invention is preferably 70 to 140 ° C, more preferably 90 to 110 ° C. If the softening point is too low, the whiteness of the recording paper tends to decrease, and if it is too high, the sensitivity tends to decrease.

In the present invention, as a developer, bisphenol A, 4-hydroxybenzoic acid ester, 4-hydroxyphthalic acid diester, phthalic acid monoester, bis- (hydroxyphenyl) sulfide, 4-
Hydroxyphenyl aryl sulfones, 4-hydroxyphenyl aryl sulfonates, 1,3-di [2-
(Hydroxyphenyl) -2-propyl] -benzenes, 4-hydroxybenzoyloxybenzoic acid esters, and bisphenol sulfones are exemplified. Specific examples of these are shown below.

Bisphenol A 4,4'-isopropylidene diphenol (also known as bisphenol A) 4,4'-cyclohexylidene diphenol p, p '-(1-methyl-normalhexylidene) diphenol 1,7 -Di (4-hydroxyphenylthio) -3,5-
Dioxaheptane

4-hydroxybenzoic acid esters benzyl 4-hydroxybenzoate ethyl 4-hydroxybenzoate propyl 4-hydroxybenzoate isopropyl 4-hydroxybenzoate butyl 4-hydroxybenzoate isobutyl 4-hydroxybenzoate isobutyl 4-hydroxybenzoate Acid methylbenzyl

4-hydroxyphthalic acid diesters 4-hydroxyphthalic acid dimethyl 4-hydroxyphthalic acid diisopropyl 4-hydroxyphthalic acid dibenzyl 4-hydroxyphthalic acid dihexyl

Phthalic acid monoesters Phthalic acid monobenzyl ester Phthalic acid monocyclohexyl ester Phthalic acid monophenyl ester Phthalic acid monomethyl phenyl ester Phthalic acid monoethyl phenyl ester Phthalic acid monopropyl benzyl ester Phthalic acid monohalogen benzyl ester Phthalic acid monoethoxy Benzyl ester

Bis- (hydroxyphenyl) sulfide
S bis - (4-hydroxy -3-tert-butyl-6
Methylphenyl) sulfide bis- (4-hydroxy-2,5-dimethylphenyl)
Sulfide Bis- (4-hydroxy-2-methyl-5-ethylphenyl) sulfide Bis- (4-hydroxy-2-methyl-5-isopropylphenyl) sulfide Bis- (4-hydroxy-2,3-dimethylphenyl)
Sulfide Bis- (4-hydroxy-2,5-dimethylphenyl)
Sulfide Bis- (4-hydroxy-2,5-diisopropylphenyl) sulfide Bis- (4-hydroxy-2,3,6-trimethylphenyl) sulfide Bis- (2,4,5-trihydroxyphenyl) sulfide Bis- ( 4-hydroxy-2-cyclohexyl-5-methylphenyl) sulfide bis- (2,3,4-trihydroxyphenyl) sulfide bis- (4,5-dihydroxy-2-tert-butylphenyl) sulfide bis- (4- Hydroxy-2,5-diphenylphenyl) sulfide bis- (4-hydroxy-2-tert-octyl-5
-Methylphenyl) sulfide

4-hydroxyphenyl aryl sulfone
S 4-hydroxy-4'-isopropoxydiphenylsulfone 4-hydroxy-4'-propoxy diphenyl sulfone 4-hydroxy-4'-n-butyl sulfone 4-hydroxy-4'-n-propoxy diphenyl sulfone

4-hydroxyphenylarylsulfona
Over preparative such 4-hydroxyphenyl benzenesulfonate 4-hydroxyphenyl -p- tolyl sulfonate 4-hydroxyphenyl-methylene sulfonate 4-hydroxyphenyl -p- chlorobenzene sulfonate 4-hydroxyphenyl -p-tert-butyl-benzenesulfonyl Nato 4-hydroxyphenyl-p-isopropoxybenzene sulfonate 4-hydroxyphenyl-1'-naphthalene sulfonate 4-hydroxyphenyl-2'-naphthalene sulfonate

1,3-di [2- (hydroxyphenyl)
-2-Propyl] benzenes 1,3-di [2- (4-hydroxyphenyl) -2-propyl] benzene 1,3-di [2- (4-hydroxy-3-alkylphenyl) -2-propyl] Benzene 1,3-di [2- (2,4-dihydroxyphenyl)-
2-Propyl] benzene 1,3-di [2- (2-hydroxy-5-methylphenyl) -2-propyl] benzene

Resorcinols 1,3-dihydroxy-6 (α, α-dimethylbenzyl) -benzene

4-hydroxybenzoyloxybenzoic acid
Ester Benzyl 4-hydroxybenzoyloxybenzoate Methyl 4-hydroxybenzoyloxybenzoate Ethyl 4-hydroxybenzoyloxybenzoate Propyl 4-hydroxybenzoyloxybenzoate Butyl 4-hydroxybenzoyloxybenzoate Isopropyl 4-hydroxybenzoyloxybenzoate 4 Tert-butyl 4-hydroxybenzoyloxybenzoate hexyl 4-hydroxybenzoyloxybenzoate octyl 4-hydroxybenzoyloxybenzoate nonyl 4-hydroxybenzoyloxybenzoate cyclohexyl 4-hydroxybenzoyloxybenzoate β-hydroxybenzoyloxybenzoate Phenyl 4-hydroxybenzoyloxybenzoic acid phenyl 4-hydroxybenzoyloxybenzoic acid α- naphthyl 4-hydroxy-benzoyloxy benzoate β- naphthyl 4-hydroxy-benzoyloxy benzoate sec- butyl

Bisphenol sulfones (I) Bis- (3-1-butyl-4-hydroxy-6-methylphenyl) sulfone Bis- (3-ethyl-4-hydroxyphenyl) sulfone Bis- (3-propyl-4-) Hydroxyphenyl) sulfone Bis- (3-methyl-4-hydroxyphenyl) sulfone Bis- (2-isopropyl-4-hydroxyphenyl)
Sulfone Bis- (2-ethyl-4-hydroxyphenyl) sulfone Bis- (3-chloro-4-hydroxyphenyl) sulfone Bis (2,3-dimethyl-4-hydroxyphenyl) sulfone Bis (2,5-dimethyl-4) -Hydroxyphenyl) sulfone Bis- (3-methoxy-4-hydroxyphenyl) sulfone 4-hydroxyphenyl-2'-ethyl-4'-hydroxyphenylsulfone 4-hydroxyphenyl-2'-isopropyl-4'-
Hydroxyphenyl sulfone 4-hydroxyphenyl-3'-isopropyl-4'-
Hydroxyphenyl sulfone 4-hydroxyphenyl-3'-sec butyl-4'-
Hydroxyphenyl sulfone 3-chloro-4-hydroxyphenyl-3'-isopropyl-4'-hydroxyphenyl sulfone 2-hydroxy-5-t-butylphenyl-4'-hydroxyphenyl sulfone 2-hydroxy-5-t-aminophenyl -4'-hydroxyphenyl sulfone 2-hydroxy-5-t-isopropylphenyl-4 '
-Hydroxyphenyl sulfone 2-hydroxy-5-t-octylphenyl-4'-hydroxyphenyl sulfone 2-hydroxy-5-t-butylphenyl-3'-chloro-4'-hydroxyphenyl sulfone 2-hydroxy-5-t -Butylphenyl-3'-methyl-4'-hydroxyphenyl sulfone 2-hydroxy-5-t-butylphenyl-3'-isopropyl-4'-hydroxyphenyl sulfone 2-hydroxy-5-t-butylphenyl-3 '-Chloro-4'-hydroxyphenyl sulfone 2-hydroxy-5-t-butylphenyl-3'-methyl-4'-hydroxyphenyl sulfone 2-hydroxy-5-t-butylphenyl-3'-isopropyl-4'- Hydroxyphenyl sulfone 2-hydroxy-5-t-butyl Eniru 2'-methyl-4'-hydroxyphenyl sulfone

Bisphenol sulfonic acid (II) 4,4'-sulfonyldiphenol 2,4'-sulfonyldiphenol 3,3'-dichloro-4,4'-sulfonyldiphenol 3,3'-dibromo-4,4 ′ -Sulfonyldiphenol 3,3 ′, 5,5′-tetrabromo-4,4′-sulfonyldiphenol 3,3′-diamino-4,4′-sulfonyldiphenol

Others p-tert-butylphenol 2,4-dihydroxybenzophenone novolac type phenol resin 4-hydroxyacetophenone p-phenylphenol benzyl-4-hydroxyphenylacetate p-benzylphenol

The basic colorless dye used in the present invention is not particularly limited, but triphenylmethane type, fluorane type, fluorene type, divinyl type and the like are preferable, and specific examples thereof are shown below.

Triphenylmethane leuco dye 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide [also known as crystal violet lactone]

Fluoran leuco dye (I) 3-diethylamino-6-methyl-7-anilinofluorane 3- (N-ethyl-p-toluidino) -6-methyl-
7-anilinofluoran 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluorane 3-diethylamino-6-methyl-7- (o, p-dimethylanilino) fluoran 3 -Pyrrolidino-6-methyl-7-anilinofluorane 3-piperidino-6-methyl-7-anilinofluorane 3- (N-cyclohexyl-N-methylamino) -6-
Methyl-7-anilinofluorane 3-diethylamino-7- (m-trifluoromethylanilino) fluorane 3-Nn-dibutylamino-6-methyl-7-anilinofluorane 3-Nn-dibutyl Amino-7- (o-chloroanilino) fluorane 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluorane 3-dibutylamino-6-methyl-7- (o, p -Dimethylanilino) fluorane 3- (N-methyl-N-propylamino) -6-methyl-7-anilinofluorane 3-diethylamino-6-chloro-7-anilinofluorane 3-dibutylamino-7- (O-Chloranilino) fluorane 3-diethylamino-7- (o-chloranilino) fluorane 3-diethylamino-6-methyl-ku Lolfluorane 3-diethylamino-6-methyl-fluorane 3-cyclohexylamino-6-chlorofluorane 3-diethylamino-benzo [a] -fluorane 3-n-dipentylamino-6-methyl-7-anilinofluorane 2- ( 4-oxo-hexyl) -3-dimethylamino-
6-Methyl-7-anilinofluorane 2- (4-oxo-hexyl) -3-diethylamino-
6-methyl-7-anilinofluorane 2- (4-oxo-hexyl) -3-dipropylamino-6-methyl-7-anilinofluorane

Fluorene type leuco dye 3,6,6'-tris (dimethylamino) spiro [fluorene-9,3'-phthalide] 3,6,6'-tris (diethylamino) spiro [fluorene-9,3'- Phthalide]

Fluoran-based leuco dye (II) 2-methyl-6-p- (p-dimethylaminophenyl)
Aminoanilinofluorane 2-Methoxy-6-p- (p-dimethylaminophenyl) aminoanilinofluorane 2-chloro-3-methyl-6-p- (p-phenylaminophenyl) aminoanilinofluorane 2 -Chloro-6-p- (p-dimethylaminophenyl)
Aminoanilinofluorane 2-nitro-6-p- (p-diethylaminophenyl)
Aminoanilinofluorane 2-amino-6-p- (p-diethylaminophenyl)
Aminoanilinofluorane 2-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluorane 2-phenyl-6-methyl-6-p- (p-phenylaminophenyl) aminoanilinofluorane 2- Benzyl-6-p- (p-phenylaminophenyl) aminoanilinofluorane 2-hydroxy-6-p- (p-phenylaminophenyl) aminoanilinofluorane 3-methyl-6-p- (p-dimethyl Aminophenyl)
Aminoanilinofluorane 3-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluorane 3-diethylamino-6-p- (p-dibutylaminophenyl) aminoanilinofluorane

Divinyl-based leuco dye 3,3-bis- [2- (p-dimethylaminophenyl)
-2- (p-Methoxyphenyl) ethenyl] -4,5,
6,7-Tetrabromophthalide 3,3-bis- [2- (p-dimethylaminophenyl)
-2- (p-Methoxyphenyl) ethenyl] -4,5,
6,7-Tetrachlorophthalide 3,3-bis- [1,1-bis (4-pyrrolidinophenyl) ethylene-2-yl] -4,5,6,7-tetrabromophthalide 3,3- Bis- [1- (4-methoxyphenyl) -1-
(4-Pyrrolidinophenyl) ethylene-2-yl]-
4,5,6,7-tetrachlorophthalide

Others 1,1-bis- [2 ', 2', 2 ", 2" -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2,
2-Dinitrileethane 1,1-bis- [2 ′, 2 ′, 2 ″, 2 ″ -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2-
β-naphthoylethane 1,1-bis- [2 ′, 2 ′, 2 ″, 2 ″ -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2,
2-Diacetylethane bis- [2,2,2 ', 2'-tetrakis- (p-dimethylaminophenyl) -ethenyl] -methylmalonic acid dimethyl ester

These dyes can be used alone or in admixture of two or more.

Further, as a sensitizer, fatty acid amides such as stearic acid amide and palmitic acid amide, ethylene bisamide, montan wax, polyethylene wax, dibenzyl terephthalate, benzyl p-benzyloxybenzoate, di-p-tolyl carbonate. , P-benzylbiphenyl, phenyl α-naphthyl carbonate, 1,4-diethoxynaphthalene, 1-hydroxy-
2-naphthoic acid phenyl ester, 1,2-di- (3-
Methylphenoxy) ethane, di (p-methylbenzyl) oxalate, β-benzyloxynaphthalene, 4-biphenyl p-tolyl ether, O-xylerin-bis- (phenyl ether), 4- (m-methylphenoxymethyl) biphenyl Etc. can also be added.

As the binder used in the present invention, a fully silicified polyvinyl alcohol having a polymerization degree of 200 to 1900, a partially silicified polyvinyl alcohol, a carboxy modified polyvinyl alcohol, an amide modified polyvinyl alcohol, a sulfonic acid modified polyvinyl alcohol, and a butyral modified polyvinyl are used. Alcohol, other modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer and ethyl cellulose, cellulose derivatives such as acetyl cellulose, polyvinyl chloride, polyvinyl acetate,
Examples thereof include polyacrylamide, polyacrylic acid ester, polyvinyl butyral polystyrol and copolymers thereof, polyamide resin, silicone resin, petroleum resin, terpene resin, ketone resin and coumarone resin. These polymeric substances are water, alcohols, ketones,
In addition to using it by dissolving it in a solvent such as ester or hydrocarbon,
It may be used in a state of being emulsified in water or another medium or dispersed in a paste form and used together depending on the required quality.

Further, in the present invention, a known stabilizer p-nitrobenzoic acid metal salt (Ca, Zn) or phthalic acid monobenzyl ester metal salt (Ca, Zn) is used within a range that does not impair the effects of the present invention. It is also possible to add.

The filler used in the present invention is silica,
Examples thereof include inorganic or organic fillers such as calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, tanks, titanium oxide, and aluminum hydroxide.

In addition to these, a release agent such as a fatty acid metal salt, a lubricant such as waxes, a benzophenone-based or triazole-based UV absorber, a water-proofing agent such as glyoxal, a dispersant, an antifoaming agent, etc. should be used. You can

The amounts of the stabilizer and basic colorless dye used in the present invention, and the types and amounts of various other components are determined according to the required performance and recording suitability, and are not particularly limited, but usually a base is used. 1 to 8 parts of organic color developer, 0.25 to 2.5 parts of stabilizer, and 1 to 20 parts of filler are used for 1 part of water-soluble colorless dye, and the binder is 10 to 25% in the total solid content.
Is appropriate. Further, the mixing ratio of the polyhydroxy aromatic compound and the bisphenol A type epoxy resin is 5: 1 to 1:
5 is preferable.

The desired heat-sensitive recording sheet can be obtained by applying the coating solution having the above composition to any support such as paper, synthetic paper, film, plastic, nonwoven fabric and the like.

Further, an overcoat layer of a polymeric substance containing a filler may be provided on the thermosensitive color developing layer for the purpose of enhancing the storage stability.

An undercoat layer containing an organic filler or an inorganic filler may be provided below the thermosensitive color developing layer for the purpose of enhancing the storage stability and sensitivity.

The above-mentioned organic color developer, basic colorless dye, stabilizer and, if necessary, materials to be added are pulverized with a crusher such as a ball mill, attritor, or sand grinder or an appropriate emulsifying device to a particle size of several microns or less. The mixture is atomized until a certain amount, and a binder and various additives according to the purpose are added to obtain a coating liquid.

[0046]

The reason why the effect of the present invention is obtained when the specific stabilizer is used in combination in the present invention is considered as follows.

First, what is excellent in the ability of dynamic coloring is
This is because the dye has a high melt-dissolving diffusion rate and a high saturation solubility in the stabilizer of the present invention, and a recorded image can be instantaneously formed by instantaneous contact of a high-heat thermal head.

Further, the fastness of the recorded image to the plasticizer is high, and the bleeding due to the plasticizer does not occur as described below. Generally, a thermal recording paper is composed of a basic colorless dye as an electron donor and an organic acidic substance such as a phenol compound, an aromatic carboxylic acid or an organic sulfonic acid as an electron acceptor. The heat-melting reaction between the basic colorless dye and the color developer is an acid-base reaction based on electron donation / acceptance, whereby a metastable "charge transfer complex" is formed and a color image is obtained. . At this time, by incorporating a bisphenol type epoxy resin in this system, it is presumed that the epoxy group is ring-opened during the heat melting reaction and reacts with the leuco dye and the organic developer to stabilize the recorded image. It When a specific polyhydric hydroxyaromatic compound and a specific bisphenol A type epoxy resin are combined in this reaction process, the ring-opening reaction of this epoxy group occurs actively, which causes the recorded image to be affected by the plasticizer under environmental conditions. It is considered that the stability of the color image is maintained even when the color image is exposed for a long period of time, and at the same time, the outflow into the heat-sensitive layer due to the penetration of the plasticizer of the color image, which is a cause of the bleeding, is prevented.

[0049]

EXAMPLES The present invention will be described below with reference to examples.
In the description, parts indicate parts by weight.

[Example 1 (Test Nos. 1 to 8)] Liquid A (Developer Dispersion Liquid) Developer (see Table 1) 6.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts water 11.2 Part B liquid (dye dispersion liquid) 3-n-dibutylamino-6-methyl 2.0 parts -7-anilinofluorane 10% polyvinyl alcohol aqueous solution 4.6 parts water 2.6 parts C liquid (stabilizer dispersion liquid) 1) Polyhydric hydroxy aromatic compound (see Table 1) 2.0 parts 10% polyvinyl alcohol aqueous solution 2.5 parts Water 1.5 parts D liquid (stabilizer dispersion 2) Bisphenol A type epoxy resin (see Table 1) 1.0 part 10% polyvinyl alcohol aqueous solution 1.3 parts water 0.7 part Each liquid of the above composition was ground to an average particle size of 1 micron with a sand grinder. Next, the dispersion liquids were mixed at the following ratios to prepare coating liquids. Liquid A 36.0 parts Liquid B 9.2 parts Liquid C 6.0 parts Liquid D 3.0 parts Kaolin clay (50% dispersion liquid) 12.0 parts Each of the above coating liquids on one side of 50 g / m ² base paper. Coating amount of 6.0
It was coated and dried so as to be g / m ² , and this sheet was treated with a super calender so that the smoothness was 500 to 600 seconds to prepare a heat-sensitive recording sheet.

[Example 2 (Test Nos. 15 to 22)] Liquid E (developing agent dispersion) Developer (see Table 2) 6.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts water 11.2 Part B liquid (dye dispersion) 3-n-dibutylamino-6-methyl 2.0 parts -7-anilinofluorane 10% polyvinyl alcohol aqueous solution 4.6 parts water 2.6 parts F liquid (stabilizer dispersion liquid) 1) Polyhydric hydroxyaromatic compound (see Table 2) 2.0 parts 10% polyvinyl alcohol aqueous solution 2.5 parts Water 1.5 parts D liquid (stabilizer dispersion 2) Bisphenol A type epoxy resin (see Table 2) 1.0 part 10% polyvinyl alcohol aqueous solution 1.3 parts water 0.7 part Each liquid of the above composition was ground to an average particle size of 1 micron with a sand grinder. Next, the dispersion liquids were mixed at the following ratios to prepare coating liquids. Liquid E 36.0 parts Liquid B 9.2 parts Liquid F 6.0 parts Liquid D 3.0 parts Kaolin clay (50% dispersion liquid) 12.0 parts Each of the above coating liquids on one side of 50 g / m ² base paper Coating amount of 6.0
It was coated and dried so as to be g / m ² , and this sheet was treated with a super calender so that the smoothness was 500 to 600 seconds to prepare a heat-sensitive recording sheet.

Comparative Example 1 (Test Nos. 9 to 11) Liquid A (Developer Dispersion Liquid) Developer (see Table 1) 6.0 parts 10% polyvinyl alcohol aqueous solution 18.8 parts water 11.2 Part B liquid (dye dispersion liquid) 3-n-dibutylamino-6-methyl 2.0 parts -7-anilinofluorane 10% polyvinyl alcohol aqueous solution 4.6 parts water 2.6 parts C liquid (stabilizer dispersion liquid) 1) Polyhydric hydroxyaromatic compound (see Table 1) 3.0 parts 10% aqueous polyvinyl alcohol solution 3.8 parts water 2.2 parts Each solution of the above composition is ground with a sand grinder to an average particle size of 1 micron. did. Next, the dispersions were mixed in the following proportions to form a coating liquid, and a thermosensitive recording sheet was prepared in the same manner as in Example 1. Liquid A 36.0 parts Liquid B 9.2 parts Liquid C 9.0 parts Kaolin clay (50% dispersion liquid) 12.0 parts

Comparative Example 2 (Test Nos. 12 to 14) Liquid A (Developer Dispersion Liquid) Developer (see Table 1) 5.0 parts 10% polyvinyl alcohol aqueous solution 18.8 parts water 11.2 Part B liquid (dye dispersion) 3-n-dibutylamino-6-methyl 2.0 part -7-anilinofluorane 10% polyvinyl alcohol aqueous solution 4.6 parts water 2.6 parts D liquid (stabilizer dispersion liquid) 2) Bisphenol A type epoxy resin (see Table 1) 3.0 parts 10% polyvinyl alcohol aqueous solution 3.8 parts water 2.2 parts Each solution of the above composition was ground to an average particle size of 1 micron with a sand grinder. . Next, the dispersions were mixed in the following proportions to form a coating liquid, and a thermosensitive recording sheet was prepared in the same manner as in Example 1. Liquid A 36.0 parts Liquid B 9.2 parts Liquid D 9.0 parts Kaolin clay (50% dispersion liquid) 12.0 parts

Comparative Example 3 (Test Nos. 23 to 25) Liquid E (Developer Dispersion Liquid) Developer (see Table 2) 6.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts water 11.2 Part B liquid (dye dispersion liquid) 3-n-dibutylamino-6-methyl 2.0 parts -7-anilinofluorane 10% polyvinyl alcohol aqueous solution 4.6 parts water 2.6 parts C liquid (stabilizer dispersion liquid) 1) Polyvalent hydroxyaromatic compound (see Table 2) 3.0 parts 10% aqueous polyvinyl alcohol solution 3.8 parts water 2.2 parts Each solution of the above composition is ground to an average particle size of 1 micron with a sand grinder. did. Next, the dispersions were mixed in the following proportions to form a coating liquid, and a thermosensitive recording sheet was prepared in the same manner as in Example 1. E liquid 36.0 parts B liquid 9.2 parts C liquid 9.0 parts Kaolin clay (50% dispersion liquid) 12.0 parts

Comparative Example 4 (Test Nos. 26 to 28) Liquid E (Developer Dispersion Liquid) Developer (see Table 2) 5.0 parts 10% polyvinyl alcohol aqueous solution 18.8 parts water 11.2 Part B liquid (dye dispersion) 3-n-dibutylamino-6-methyl 2.0 part -7-anilinofluorane 10% polyvinyl alcohol aqueous solution 4.6 parts water 2.6 parts D liquid (stabilizer dispersion liquid) 2) Bisphenol A type epoxy resin (see Table 2) 3.0 parts 10% aqueous polyvinyl alcohol solution 3.8 parts water 2.2 parts Each liquid of the above composition was ground to an average particle size of 1 micron with a sand grinder. . Next, the dispersions were mixed in the following proportions to form a coating liquid, and a thermosensitive recording sheet was prepared in the same manner as in Example 1. E liquid 36.0 parts B liquid 9.2 parts D liquid 9.0 parts Kaolin clay (50% dispersion liquid) 12.0 parts

The results of a quality performance test conducted on the thermal recording sheets obtained in the above Examples and Comparative Examples are summarized in Tables 1 and 2.

[0057]

[Table 1]

[Table 2]

[Table 3]

[Table 4]

Note (1) Dynamic color density; manufactured by Tokyo Shibaura Electric Co., Ltd.
Thermal facsimile KB-4800 is used and the applied voltage is 1
The image density recorded at 8.03 V and a pulse width of 3.2 milliseconds was measured with a Macbeth densitometer (RD-914, using an amber filter. The same applies hereinafter). Note (2) Plasticizer resistance: The image density of the sample dynamically printed by the method of Note (1) was measured with a Macbeth densitometer and taken as the untreated density. And vinyl chloride film (Mitsui Toatsu High Wrap KMA) on the front and back of this printed sample
The image densities after stacking for 24 hours in a constant temperature tester at 40 ° C. were measured with a Macbeth densitometer. The residual rate is calculated from the following formula.

[Equation 1] Note (3) Bleeding due to plasticizer; The degree of bleeding of the residual image portion of the sample subjected to the plasticizer test according to the method of Note (2) to the white paper portion was visually determined. ⊚: No bleeding was observed ◯: Almost no bleeding was observed Δ: Bleeding was observed ×: Bleeding was observed considerably

In Tables 1 and 2 above, regarding the bisphenol A type epoxy resin, the symbol A is bisphenol A type epoxy resin (Asahi Kasei: trade name AE R664P),
Symbol B is bisphenol A type epoxy resin (Asahi Kasei: trade name AER664), symbol C is bisphenol A
Type epoxy resin (Asahi Kasei: trade name AE R661
Y) is shown.

[0060]

【The invention's effect】

(1) Since the thermal response is excellent, a clear high density image can be obtained even at high speed and high density recording. (High sensitivity) (2) The image area does not fade or bleed even when contacted with a plasticizer. (Plasticizer resistance)

Claims (2)

[Claims] 1. A thermosensitive recording sheet comprising a support and a thermosensitive color developing layer containing a colorless or pale basic colorless dye and an organic developer as main components, wherein the thermosensitive color developing layer serves as a stabilizer. A heat-sensitive recording sheet comprising a polyvalent hydroxyaromatic compound represented by the general formula (I) and a bisphenol A type epoxy resin represented by the following formula (II). [Chemical 1] [Chemical 2] 2. The heat-sensitive recording sheet according to claim 1, wherein the polyvalent hydroxyaromatic compound is stearyl gallate.