JP2734504B2 - Thermal recording sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosensitive 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 prepared by grinding and dispersing a colorless or pale-colored basic colorless dye and an organic color developer such as a phenolic substance into fine particles, and then mixing and dispersing them together. A coating solution obtained by adding an agent, a sensitivity improver, a lubricant and other auxiliaries to a support such as paper, synthetic paper, film, plastic, etc. The color recording is obtained by an instantaneous chemical reaction caused by heating such as described above.

[0003] These thermosensitive recording sheets are used for measuring recorders, computer terminal printers, facsimile,
It has been applied to a wide range of fields such as automatic ticket vending machines and bar code labels, but recently, as these recording devices have been diversified and improved in performance, the required quality of thermal recording sheets has become higher. . For example, it is required that a high-density and vivid color image can be obtained even with a small amount of heat energy accompanying the high-speed recording, and on the other hand, light fastness,
There is a demand for a heat-sensitive recording sheet having excellent storability 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
However, such a conventional heat-sensitive recording material has, for example, a low thermal response, and cannot provide a sufficient color density at the time of high-speed recording.

As a method for remedying such a defect, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluoran is used as a leuco dye (JP-A-49-109120). Dibutylamino-
Highly sensitive dyes such as those using 6-methyl-7-anilinofluoran (JP-A-59-190891) have been developed, and as a color developing agent, a substance having a good coloring property, 1,7-
Bis (4-hydroxyphenylthio) -3,5-dioxaheptane (JP-A-59-106456);
By using 5-bis (4-hydroxyphenylthio) -3-oxaheptane (JP-A-59-116262) and 4-hydroxy-4'-isopropoxydiphenylsulfone (JP-B-63-46067). Techniques for increasing the speed and increasing the sensitivity have been disclosed.

[0006]

However, these heat-sensitive recording sheets have extremely poor storage stability of the recorded images. Therefore, when printed with a bar code printer, the color-developed images are wrapped with a wrapping material such as a PVC film. Contact with a plasticizer (DOP, DOA, etc.) contained in the film causes a significant decrease in image density and bleeding, resulting in a problem that reading with a bar code reader is hindered.

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

[0008]

According to the present invention, a specific epoxidized diphenylsulfone derivative represented by the general formula (I) and a bisphenol A type epoxy resin represented by the formula (II) are used as a stabilizer in a thermosensitive coloring layer. The above-mentioned problem has been solved at a glance by containing it.

[0009]

Embedded image Is shown. Here, R ₁ and R ₂ each represent a hydrogen atom or a methyl group, α represents 0 or an integer of 1 to 5, and β and γ each represent an integer of 1 to 5. B is Is shown. C represents a chlorine atom, a bromine atom, a methyl group,
M represents 0 or an integer of 1 to 2;
Indicates a number. ]

Embedded image [In the formula, n represents an integer of 1 to 20. ]

Specific examples of the epoxidized diphenylsulfone derivative represented by the above general formula (I) used in the present invention include, for example, those represented by the following compound No.

[0011]

Embedded image

Embedded image

Embedded image

Of course, it is not limited to these,
If necessary, two or more compounds can be used in combination.

The softening point of the bisphenol A type epoxy resin used in the present invention is preferably 70 to 140 ° C., more preferably about 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 is lowered.

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

Bisphenol A 4,4'-isopropylidene diphenol (alias: 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 4-Hydroxybenzoate Methyl benzyl

4-Hydroxyphthalic acid diesters Dimethyl 4-hydroxyphthalate Diisopropyl 4-hydroxyphthalate Dibenzyl 4-hydroxyphthalate Dihexyl 4-hydroxyphthalate

Monoesters of phthalic acid Monobenzyl phthalate Monocyclohexyl phthalate Monophenyl phthalate Monomethyl phenyl phthalate Monoethyl phenyl phthalate Monopropyl benzyl phthalate Monohalogen benzyl phthalate Monoethoxy phthalate 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

[0020] 4-hydroxyphenylaryl sulfone
S 4-hydroxy-4'-isopropoxy diphenylsulfone <br/> phon 4 - hydroxy-4'-n-butyl sulfone 4-hydroxy-4'-n-propoxy diphenyl sulfone

[0021] 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-isopropoxybenzenesulfonate 4-hydroxyphenyl-1'-naphthalenesulfonate 4-hydroxyphenyl-2'-naphthalenesulfonate

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 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

[0024] 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 4-hydroxybenzoyloxybenzoate β- Phenethyl 4-hydroxybenzoyloxybenzoate phenyl 4-hydroxybenzoyloxybenzoate α- naphthyl 4-hydroxy-benzoyloxy benzoate β- naphthyl 4-hydroxy-benzoyloxy benzoate sec- butyl

Bisphenolsulfones (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'-
Hydroxyphenylsulfone 4-hydroxyphenyl-3'-isopropyl-4'-
Hydroxyphenylsulfone 4-hydroxyphenyl-3'-secbutyl-4'-
Hydroxyphenylsulfone 3-chloro-4-hydroxyphenyl-3'-isopropyl-4'-hydroxyphenylsulfone 2-hydroxy-5-t-butylphenyl-4'-hydroxyphenylsulfone 2-hydroxy-5-t-aminophenyl -4'-hydroxyphenylsulfone 2-hydroxy-5-t-isopropylphenyl-4 '
-Hydroxyphenylsulfone 2-hydroxy-5-t-octylphenyl-4'-hydroxyphenylsulfone 2-hydroxy-5-t-butylphenyl-3'-chloro-4'-hydroxyphenylsulfone 2-hydroxy-5-t - butylphenyl-3'-methyl-4'-hydroxyphenyl sulfone 2-hydroxy -5-t-butylphenyl-3'-isopropyl-4'-hydroxyphenyl sulfo down 2 - hydroxy -5-t-butyl-phenyl-2 '-Methyl-4'-hydroxyphenyl sulfone

Bisphenolsulfonic 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

Other p-tert-butylphenol 2,4-dihydroxybenzophenone novolak type phenolic resin 4-hydroxyacetophenone p-phenylphenol benzyl-4-hydroxyphenylacetate p-benzylphenol

The basic colorless dye used in the present invention is not particularly limited, but is preferably a triphenylmethane type, a fluoran type, a fluorene type, a divinyl type or the like, 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-anilinofluoran 3- (N-ethyl-p-toluidino) -6-methyl-
7-anilinofluoran 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluoran 3-diethylamino-6-methyl-7- (o, p-dimethylanilino) fluoran 3 -Pyrrolidino-6-methyl-7-anilinofluoran 3-piperidino-6-methyl-7-anilinofluoran 3- (N-cyclohexyl-N-methylamino) -6
Methyl-7-anilinofluoran 3-diethylamino-7- (m-trifluoromethylanilino) fluoran 3-Nn-dibutylamino-6-methyl-7-anilinofluoran 3-Nn-dibutyl Amino-7- (o-chloroanilino) fluoran 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluoran 3-dibutylamino-6-methyl-7- (o, p -Dimethylanilino) fluoran 3- (N-methyl-N-propylamino) -6-methyl-7-anilinofluoran 3-diethylamino-6-chloro-7-anilinofluoran 3-dibutylamino-7- (O-chloroanilino) fluoran 3-diethylamino-7- (o-chloroanilino) fluoran 3-diethylamino-6-methyl-c Lorfluoran 3-diethylamino-6-methyl-fluoran 3-cyclohexylamino-6-chlorofluoran 3-diethylamino-benzo [a] -fluoran 3-n-dipentylamino-6-methyl-7-anilinofluoran 2- ( 4-oxo-hexyl) -3-dimethylamino-
6-methyl-7-anilinofluoran 2- (4-oxo-hexyl) -3-diethylamino-
6-methyl-7-anilinofluoran 2- (4-oxo-hexyl) -3-dipropylamino-6-methyl-7-anilinofluoran

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

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

Divinyl 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

Other 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 combination of two or more.

Further, as sensitizers, 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 and the like can also be added.

[0037] As binder to be used in the present invention, fully Quai emissions polyvinyl alcohol with a polymerization degree of 200-1900, partially Ke emissions polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, butyral Modified polyvinyl alcohol, other modified polyvinyl alcohol, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer and cellulose derivatives such as ethylcellulose, acetylcellulose, polyvinyl chloride, polyacetic acid vinyl,
Examples thereof include polyacrylamide, polyacrylate, polyvinyl butyral polystyrene, and copolymers thereof, polyamide resin, silicone resin, petroleum resin, terpene resin, ketone resin, and cumarone resin. These macromolecules are water, alcohol, ketone,
In addition to dissolving in solvents such as esters and hydrocarbons,
It is used in a state of being emulsified or dispersed in a paste form in water or another medium, and may be used in combination depending on required quality.

[0038] In the present invention, known stabilizer p- nitrobenzoic acid metal salt effective in not jeopardized the present invention (Ca, Zn) or lid Le acid monobenzyl ester metal salt (Ca, Zn) Can also be added.

As the filler used in the present invention, silica,
Calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, data Torque, titanium oxide, and the like inorganic or organic fillers such as aluminum hydroxide.

In addition, a releasing agent such as a fatty acid metal salt, a lubricant such as a wax, a benzophenone-based or triazole-based ultraviolet absorber, a water-proofing agent such as glyoxal, a dispersant, and an antifoaming agent. Can be.

The amounts of the stabilizer and the basic colorless dye used in the present invention and the types and amounts of other various components are determined according to the required performance and recording suitability, and are not particularly limited. 1 to 8 parts of an organic color developer, 0.25 to 2.5 parts of a stabilizer, and 1 to 20 parts of a filler are used for 1 part of a neutral colorless dye, and a binder is 10 to 25% of the total solid content.
Is appropriate. The mixing ratio of the epoxidized diphenyl sulfone derivative and the bisphenol A type epoxy resin is 5:
1-1: 5 is preferred.

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

Further, an overcoat layer of a polymer material containing a filler or the like can be provided on the thermosensitive coloring layer for the purpose of enhancing the storage stability.

Further, an undercoat layer containing an organic filler or an inorganic filler can be provided below the thermosensitive coloring layer for the purpose of enhancing the storage stability and sensitivity.

The above-mentioned organic color developer, basic colorless dye, stabilizer, and materials to be added as necessary are reduced to a particle size of several microns or less by a pulverizer such as a ball mill, an attritor, a sand grinder or an appropriate emulsifying device. It is pulverized to the extent necessary, and a coating liquid is prepared by adding a binder and various additives according to the purpose.

[0046]

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

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

The reason why the recorded image has high fastness to the plasticizer and does not cause bleeding due to the plasticizer is explained as follows. In general, a thermosensitive recording paper is constituted by using 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 these basic colorless dyes and the developer is an acid-base reaction based on donation and acceptance of electrons, whereby a metastable "charge transfer complex" is formed and a colored image is obtained. . At this time, it is presumed that the inclusion of the epoxidized diphenylsulfone derivative in this system causes the epoxy group to open during the heat melting reaction, reacting with the leuco dye and the organic developer, and stabilizing the recorded image. Is done. When a specific epoxidized diphenylsulfone derivative is combined with a specific bisphenol A type epoxy resin in this reaction process, a ring opening reaction of this epoxy group occurs actively,
Therefore, even if the recorded image is exposed to the environmental conditions affected by the plasticizer for a long period of time, the stability of the colored image is maintained, and at the same time, the outflow of the colored image into the heat-sensitive layer due to the penetration of the plasticizer, which is a cause of bleeding, is maintained. It is thought to prevent.

[0049]

The present invention will be described below with reference to examples.
In addition, in description, a part shows a weight part. [Example 1 (Test Nos. 1 to 8)] Liquid A (color developer dispersion) Color developer (see Table 1) 6.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts Water 11.2 parts Liquid B (Dye dispersion liquid) 3-n-dibutylamino-6-methyl 2.0 parts -7-anilinofluoran 10% aqueous polyvinyl alcohol solution 4.6 parts Water 2.6 parts Liquid C (stabilizer dispersion liquid 1) Epoxy Diphenyl sulfone derivative (see Table 1) 2.0 parts 10% aqueous polyvinyl alcohol solution 2.5 parts Water 1.5 parts Liquid D (stabilizer dispersion liquid 2) Bisphenol A type epoxy resin (see Table 1) 1.0 part 1.3 parts of 10% aqueous polyvinyl alcohol solution 0.7 parts of water Each liquid of the above composition was ground by a sand grinder to an average particle diameter of 1 micron. Subsequently, the dispersion liquid was mixed at the following ratio to obtain a coating liquid. Liquid A 36.0 parts Liquid B 9.2 parts Liquid C 6.0 parts Liquid D 3.0 parts Kaolin clay (50% dispersion) 12.0 parts One side of each of the above coating liquids at 50 g / m ² base paper 6.0 coating amount
g / m ² and dried, and this sheet was treated with a super calender so that the smoothness became 500 to 600 seconds to prepare a heat-sensitive recording sheet.

[Comparative Example 1 (Test Nos. 9 to 11)] Solution E (Developer dispersion) 6.0 parts of 4-hydroxy-4'-isopropoxydiphenylsulfone 18.8 parts of 10% aqueous solution of polyvinyl alcohol Water 11.2 parts Liquid B (dye dispersion liquid) 3-n-dibutylamino-6-methyl 2.0 parts -7-anilinofluoran 10% aqueous solution of polyvinyl alcohol 4.6 parts Water 2.6 parts Liquid F (stable Dispersant 1) Epoxidized diphenylsulfone derivative (see Table 1) 3.0 parts 10% aqueous polyvinyl alcohol solution 3.8 parts Water 2.2 parts Each liquid of the above composition was sand-grindered to an average particle diameter of 1 micron. Ground. Next, a dispersion was mixed at the following ratio to form a coating liquid, and a heat-sensitive recording sheet was prepared in the same manner as in Example 1. E liquid 36.0 parts B liquid 9.2 parts F liquid 9.0 parts Kaolin clay (50% dispersion) 12.0 parts

[Comparative Example 2 (Test Nos. 12 to 14)] Solution E (Developer dispersion) 5.0 parts of 4-hydroxy-4'-isopropoxydiphenylsulfone 18.8 parts of a 10% aqueous solution of polyvinyl alcohol Water 11.2 parts B liquid (dye dispersion liquid) 3-n-dibutylamino-6-methyl 2.0 parts -7-anilinofluoran 10% aqueous solution of polyvinyl alcohol 4.6 parts water 2.6 parts G liquid (stable Dispersant 2) Bisphenol A type epoxy resin (see Table 1) 3.0 parts 10% aqueous solution of polyvinyl alcohol 3.8 parts Water 2.2 parts Each liquid of the above composition is sand-grindered to an average particle diameter of 1 micron. Ground. Next, a dispersion was mixed at the following ratio to form a coating liquid, and a heat-sensitive recording sheet was prepared in the same manner as in Example 1. E liquid 36.0 parts B liquid 9.2 parts G liquid 9.0 parts Kaolin clay (50% dispersion) 12.0 parts

Example 2 (Test Nos. 15 to 22) Liquid A (Developer dispersion) Developer (see Table 2) 6.0 parts 10% aqueous solution of polyvinyl alcohol 18.8 parts Water 11.2 Part B liquid (dye dispersion liquid) 3-n-dibutylamino-6-methyl 2.0 parts -7-anilinofluoran 10% aqueous polyvinyl alcohol solution 4.6 parts water 2.6 parts liquid C (stabilizer dispersion liquid) 1) Epoxidized diphenylsulfone derivative (see Table 2) 2.0 parts 10% aqueous solution of polyvinyl alcohol 2.5 parts Water 1.5 parts Liquid D (stabilizer dispersion liquid 2) Bisphenol A type epoxy resin (see Table 2) 0.0 part 10% aqueous solution of polyvinyl alcohol 1.3 parts Water 0.7 part Each liquid of the above composition was ground with a sand grinder to an average particle diameter of 1 micron. Subsequently, the dispersion liquid was mixed at the following ratio to obtain a coating liquid. Liquid A 36.0 parts Liquid B 9.2 parts Liquid C 6.0 parts Liquid D 3.0 parts Kaolin clay (50% dispersion) 12.0 parts One side of each of the above coating liquids at 50 g / m ² base paper 6.0 coating amount
g / m ² and dried, and this sheet was treated with a super calender so that the smoothness became 500 to 600 seconds to prepare a heat-sensitive recording sheet.

Comparative Example 3 (Test Nos. 23 to 25) Liquid H (developer dispersion liquid) 4,4'-isopropylidenediphenol 6.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts Water 11. 2 parts liquid B (dye dispersion liquid) 3-n-dibutylamino-6-methyl 2.0 parts -7-anilinofluoran 10% aqueous polyvinyl alcohol solution 4.6 parts water 2.6 parts liquid F liquid (stabilizer dispersion) Liquid 1) Epoxidized diphenylsulfone derivative (see Table 2) 3.0 parts 10% aqueous solution of polyvinyl alcohol 3.8 parts Water 2.2 parts Each liquid of the above composition is ground with a sand grinder to an average particle diameter of 1 micron. did. Next, a dispersion was mixed at the following ratio to form a coating liquid, and a heat-sensitive recording sheet was prepared in the same manner as in Example 1. Liquid H 36.0 parts Liquid B 9.2 parts Liquid F 9.0 parts Kaolin clay (50% dispersion) 12.0 parts

[Comparative Example 4 (Test Nos. 26 to 28)] Liquid H (developer dispersion liquid) 4,4'-isopropylidenediphenol 5.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts water 11. 2 parts liquid B (dye dispersion liquid) 3-n-dibutylamino-6-methyl 2.0 parts -7-anilinofluoran 10% aqueous solution of polyvinyl alcohol 4.6 parts water 2.6 parts liquid G (stabilizer dispersion) Liquid 2) Bisphenol A type epoxy resin derivative (see Table 2) 3.0 parts 10% aqueous polyvinyl alcohol solution 3.8 parts Water 2.2 parts Polish each liquid of the above composition to an average particle diameter of 1 micron with a sand grinder. Crushed. Next, a dispersion was mixed at the following ratio to form a coating liquid, and a heat-sensitive recording sheet was prepared in the same manner as in Example 1. Liquid H 36.0 parts Liquid B 9.2 parts Liquid G 9.0 parts Kaolin clay (50% dispersion) 12.0 parts

The results of quality tests performed on the heat-sensitive recording sheets obtained in the above Examples and Comparative Examples are summarized in Tables 1 and 2.

[0056]

[Table 1]

[Table 2]

[Table 3]

[Table 4]

Note (1) Dynamic color density; manufactured by Tokyo Shibaura Electric Co., Ltd.
Using thermal facsimile KB-4800, applied voltage 1
The image density recorded at 8.03 V and a pulse width of 3.2 ms 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 was regarded as an unprocessed density. Then, a vinyl chloride film (Hilab KMA manufactured by Mitsui Toatsu) is formed on the front and back surfaces of the printed sample.
Were placed in a thermostat at 40 ° C. for 24 hours, and the image density was measured with a Macbeth densitometer. The residual rate is calculated from the following equation.

(Equation 1) Note (3) Bleeding due to plasticizer; The degree of bleeding of the remaining image portion of the sample subjected to the plasticizer test by the method of Note (2) into a blank portion was visually determined. ◎: No bleeding observed ○: Almost no bleeding observed △: Bleeding observed ×: Bleeding was observed very badly

In Tables 1 and 2 above, for the bisphenol A type epoxy resin, the symbol A is a bisphenol A type epoxy resin (Asahi Kasei: AER664P),
Symbol B is bisphenol A type epoxy resin (Asahi Kasei: AER R664), symbol C is bisphenol A
Type epoxy resin (Asahi Kasei: AER661)
Y) is shown.

[0059]

【The invention's effect】

(1) Because of its excellent thermal response, 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)

(57) [Claims] 1. A thermosensitive recording sheet comprising a support having thereon a heat-sensitive coloring layer containing a colorless or light-colored basic colorless dye and an organic developer as main components. A thermosensitive recording sheet comprising an epoxidized diphenylsulfone derivative represented by the general formula (I) and a bisphenol A type epoxy resin represented by the following formula (II). Embedded image Is shown. Here, R ₁ and R ₂ each represent a hydrogen atom or a methyl group, α represents 0 or an integer of 1 to 5, and β and γ each represent an integer of 1 to 5. B is Is shown. C represents a chlorine atom, a bromine atom, a methyl group,
M represents 0 or an integer of 1 to 2;
Indicates a number. ] [In the formula, n represents an integer of 1 to 20. ] 2. The method according to claim 1, wherein the epoxidized diphenylsulfone derivative is 4-benzyloxy-4 ′-(2,3-epoxy-2).
The heat-sensitive recording sheet according to claim 1, which is -methylpropoxy) diphenyl sulfone.