JPH03159782A - Thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a thermal recording material excellent in thermal response properties and with a high coloring sensitivity by containing a specific compound in a thermal recording material containing a dye precursor and an electron acceptor compound reacting upon being heated to color the dye precursor. CONSTITUTION:A compound indicated by Formula 1 is contained in a thermal recording material containing a normally colorless or light-colored dye precursor and an electron acceptor compound (developer) reacting upon being heated to color the dye precursor. In Formula 1, X and Y respectively indicate an oxygen or sulphur atom and may be identical with or different from each other. Also, Z forms an alkylene chain with two carbon atoms or more and may have an alkyl group as a side chain. Further, Ar indicates a substituted or unsubstituted aryl group.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a heat-sensitive recording material, and particularly to a heat-sensitive recording material with excellent thermal responsiveness.

<Prior art> Heat-sensitive recording materials generally have a heat-sensitive recording layer on a support, the main components of which are an electron-donating, usually colorless or light-colored dye precursor and an electron-accepting color developer. By heating with a thermal pen, laser light, etc., a dye precursor and a color developer react instantaneously to obtain a recorded image, and are disclosed in Japanese Patent Publication No. 43-4160, Japanese Patent Publication No. 45-14039, etc. has been done. These heat-sensitive recording materials have the advantages of being able to record with relatively simple equipment, being easy to maintain, and producing no noise. It is used in a wide range of fields, including ticket vending machines.

Particularly in the field of facsimile, the demand for heat-sensitive systems is increasing significantly, and efforts are being made to increase speed, miniaturize devices, and lower prices in order to reduce transmission costs. As a result, the amount of energy required for image printing has been steadily decreasing in recent apparatuses. Therefore, there has been a strong demand for the development of highly sensitive heat-sensitive recording materials with high thermal responsiveness that can cope with such higher speed and lower energy facsimiles. In high-speed recording, it is necessary to use the small amount of thermal energy emitted from the thermal head in an extremely short period of time (usually less than 1 millisecond) for color reactions as efficiently as possible to produce highly concentrated colored images. It is.

As a means to achieve the above objective, it is proposed to use a thermofusible substance with a relatively low melting point as a color development accelerator or sensitizer together with a dye precursor and an electron-accepting compound that causes the dye precursor to develop color. has been done. For example, JP-A-57
-64593, JP-A-58-87094 disclose naphthol derivatives, JP-A-57-64592, JP-A-57-185187, JP-A-57-191089,
JP-A-58-110289, JP-A-59-15393
The patent publication discloses naphthoic acid derivatives in JP-A-58-7249.
No. 9 and JP-A-58-87088 propose the use of ether and ester derivatives of phenolic compounds.

However, the heat-sensitive recording materials produced using these methods are still insufficient in terms of thermal response, color development sensitivity, etc.

<Objective of the Invention> An object of the present invention is to obtain a heat-sensitive recording material having excellent thermal responsiveness and high color development sensitivity.

<Structure of the Invention> A heat-sensitive recording material containing a normally colorless or light-colored dye precursor and an electron-accepting compound (color developer) that reacts with the dye precursor upon heating to cause the dye precursor to develop a color, which is represented by the following general formula. By incorporating the compound, it was possible to obtain a heat-sensitive recording material with excellent thermal responsiveness and high color density.

General formula (however, in the above formula, X and Y represent oxygen or sulfur atoms,
They may be the same or different.

Further, 2 forms an alkylene chain having 2 or more carbon atoms, and may have an alkyl group side chain.

Further, Ar represents a substituted or unsubstituted aryl group. ) In the above general formula, substituents for the aryl group include a halogen atom, an alkyl group, an alkylthio group, an alkenyl group, an alkoxy group, an aralkyl group, an aralkyloxy group, a nitro group, a cyano group, etc. Not limited. Moreover, these substituents may further have a substituent.

Specific examples of the compounds of the present invention include those listed below, but the present invention is not limited thereto.

(1) 2-(4-penzyloxyphenyl)-1,
3-dioxane (2) 2-(4-penzyloxyphenyl)-1.
3-dithiane (3) 2-(4-penzyloxyphenyl)-1.
3-Dithiolane 4.5-dimethyl-2-(4-penzyloxyphenyl)-1.3-dithiolane 2- [4- (4-methylbenzyloxy)phenyl]-1.3-dioxane 2- [4- (4-methylbenzyloxy)phenyl]-1,3-dioxolane2-[4-(4-methylbenzyloxy)phenyl]-
1.3-dithiane 2- [4- (4-methylbenzyloxy)phenyl]-1.3-dithiolane 2- [4- (4-methylbenzyloxy)phenyl]-1.3-oxathiolane 4.6-dimethyl -2- [4- (4-methylbenzyloxy)phenyl-1,3-dioxane (11) 4-methyl-2- [4- (4-methylbenzyloxy)phenyl]-1,3-dithiolane 4.5 -dimethyl-2- [4- (4-me(12) (8) (9) (6) (4) (5) (7) (10) thylbenzyloxy)phenyl]-1,3-dithiolane 2- [4-(3-methylbenzyloxy)phenyl]-1,3-dioxane2- [4-(3-methylbenzyloxy)phenyl]-1,3-dithiane2-[4-(3-methylbenzyloxy) phenyl]-1,3-dithiolane4,5-dimethyl-2-[4-(3-methylbenzyloxy)phenyl1-1,3-dithiolane2-[4-(2-methylbenzyloxy)phenyl]-1 .3-dithiane(18)2-[4-(2-methylbenzyloxy)phenyl]-1.3-dithiolane2-[4-(4-methoxybenzyloxy)phenyl]-1.3-dioxane2- [4-(4-methoxybenzyloxy)phenyl-1,3-dithiane2- [4-(4-methoxybenzyloxy)(20) (14) (13) (15) (16) (17) (19) (2 ■) phenyl]-1,3-dithiolane 4,5-dimethyl-2- [4- (4-methoxybenzyloxy) phenyl]-1,3-dithiolane 2- [4- (3-methoxybenzyloxy) phenyl]-1,3-dithiane2-[4-(3-methoxybenzyloxy)phenyl]-1,3-dithiolane2-[4-(4-chloropenzyloxy)phenyl-1,3-dioxane (26) 2- [4- (4-chlorobenzyloxy)
phenyl]-1,3-dithiane2-[4-(4-chloropenzyloxy)phenyl]
-1.3-dithiolane 2- [4- (4-chlorobenzyloxy)phenyl] -1.3-oxathiolane 4-methyl-2- [4- (4-chlorobenzyloxy)phenyl] -1.3- Dithiolane 4,5-dimethyl-2- [4- (4-k(22) (23) (28) (29) (24) (27) (30) (25) lolobenzyloxy)phenyl-1,3-dithiolane (3 1)2-[4-(3-chloropenzyloxy)
phenyl]-1,3-dithiane (32) 2- [4- (3-chloropenzyloxy)
phenyl]-1,3-dithiolane (33) 2- [4- (2-chlorobenzyloxy)
phenyl]-1,3-dithiane (34) 2- [4- (2-chlorobenzyloxy)
phenyl]-1,3-dithiolane (35) 2- [4- (2,4-dimethylbenzyl)
Oxyphenyl]-1,3-dithiane(36)2-[4-(2,4-dimethylbenzyloxy)phenyl]-1,3-dithiolane(37)2-[4-(3,4-dimethylbenzyloxy) phenyl]-1,3-dithiane(38)2-[
4-(3.4-dimethylbenzyloxy)phenyl]-
1,3-dithiolane (39) 2- [4- (2,4-dichlorobenzyloxy)phenyl]-1,3-dithiane (40) 2- [4- (
2.4-dichlorobenzyloxy)phenyl]-1.3
-dithiolane (4 1) 2- [4- (3.4-dimethylbenzyloxy)phenyl]-1.3-dithiane 2- [4-
(3.4-dimethylbenzyloxy)phenyl]-1.
3-Dithiolane 2- [4- (2,6-dichlorobenzyloxy)phenyl]-1,3-dithiane 2-[4- (2,6-dichlorobenzyloxy)phenyl]-1,3-dithiolane 2- [4-(4-ethylbenzyloxy)phenylco-1,3-dioxane2-[4-(4-ethylbenzyloxy)phenylco-1,3-dithiane2-[4-(4-ethylbenzyloxy)(44 ) (46) (43) (47) (42) (45) Phenyl]-1,3-dithiolane 2- [4- (4-isopropylbenzyloxy)phenyl]-1,3-dithiane 2- [4- (4-isopropylbenzyloxy)phenyl]-1,3-dithiolane 2- [4- (4-methylthiobenzyloxy)phenyl]-1.3-dioxane 2-[4- (4-methylthiobenzyloxy)phenyl] -1.3-dithiane(52)2-[4-(4-methylthiobenzyloxy)phenyl]-1,3-dithiolane 4.5-dimethyl-2-[4-(4-methylthiobenzyloxy)phenyl], -1.3-Dithiolane 2- [4- (3-methylthiobenzyloxy)phenyl]-1.3-dithiane 2- [4- (3-methylthiobenzyloxy)phenyl]-1.3-dithiolane 2- [4 - (1-naphthylmethoxy)ph(48) (53) (55) (51) (49) (50) (54) (56) enyl]-1,3-dioxane 2-[4- (1-naphthylmethoxy) ) phenyl] −
1,3-dithiane2-[4-(1-naphthylmethoxy)phenyl]-1,3-dithiolane(59)2-[4-(4-nitropenzyloxy)
phenyl-1,3-dioxane2-[4-(4-nitropenzyloxy)phenyl]-1,3-dioxolane2-[4-(4-nitropenzyloxy)phenyl]
-1.3-dithiolane 2- [4- (4-nitropenzyloxy)phenyl]-1.3-oxathiolane 2- [4- (3-nitrobenzyloxy)phenyl]-1.3-dioxane 2- [4 -(3-Nitropenzyloxy)phenyl]-1.3~dithiane2-[4. -(3-nitropenzyloxy)phenyl]
-1.3-dithiolane 2- [4- (2-nitropenzyloxy) (62) (65) (60) (63) (66) (61) (58) (57) (64) (67) (68 ) (69) (70) (71) (72) (73) (74) (75) (76) Phenyl]-1.3-dioxane 2-[4-(2-nitrobenzyloxy)phenyl]-1. 3-dithiane 2-[4- (2-nitrobenzyloxy)phenyl]
-L 3-dithiolane 2- [4- (4-cyanobenzyloxy)phenyl]-1.3-dioxane 2- [4- (4-cyanobenzyloxy)phenyl]-1.3-dioxolane 2- [4- (4-cyanobenzyloxy)phenyl]-1,3-dithiolane 2- [4- (4-cyanobenzyloxy)phenyl]-1.3-oxathiolane 2- [4- (3-cyanobenzyloxy)phenyl]- 1.3-dioxane 2-[4-(3-cyanobenzyloxy)phenyl]-1.3-dithiane 2-[4-(3-cyanobenzyloxy)phenyl]
-1.3-dithiolane 2- [4- (2-cyanobenzyloxy)phenyl]-1.3-dioxane (77) 2- [4- (2-cyanobenzyloxy)
phenylco1,3-dithiane2-[4-(2-cyanobenzyloxy)phenylco1,3-dithiolane2-[4-(4-vinylbenzyloxy)phenyl]-1,3-dioxane2-[4- (4-vinylbenzyloxy)phenyl-1,3-dioxolane 2- [4- (4-vinylbenzyloxy)phenyl-1,3-dithiolane 2- [4- (4-vinylbenzyloxy)phenyl]-1.3- Oxathiolane 2- [4- (4-penzylbenzyloxy)phenyl]-1,3-dioxane 2- [4- (4-penzylbenzyloxy) phenyl]-1,3-dithiane 2- [4- (4 -penzylbenzyloxy)phenyl]-1,3-dithiolane 2- [4- (4-penzyloxybenzi(85) (83) (78) (79) (80) (81) (82) (84) (86) phenyl]-1,3-dioxane 2- [4- (4-benzyloxybenzyloxy)
phenyl]-1.3-dithiane(88)2-[4-(4-benzyloxybenzyloxy)phenyl]-1.3-dithiolane 2-[4-(4-benzyloxybenzyloxy)phenyl]-1. 3-Oxathiolane 4-methyl-2- [4- (4-benzyloxybenzyloxy) phenyl]-1,3-dithiolane 4,5-dimethyl-2- [4- (4-penzyloxybenzyloxy) phenyl] -1,3-dithiolane 2- {4- [4- (3-chlorobenzyloxy)
penzyloxy]phenyl} 1.3-dithiane (87) (87) (88) (89) (90) (9 1) 2- {4- [4- (2-chlorobenzyloxy)penzyloxy]phenyl}-1. 3-Dithiane The compound of the present invention can be easily synthesized by known methods. For example, 4-hydroxybenzaldehyde and a diol, such as propanediol or a dithiol, such as ethanedithiol, are reacted, usually using an acid catalyst;
A cyclic acetal or a cyclic dithioacetal can be obtained. In this case, the reaction with the diol is usually carried out while removing water. Furthermore, the desired compound can be obtained by reacting the obtained phenolic compound with, for example, benzyl bromide in the presence of an alkali. Also, 4
A desired compound can also be obtained by reacting -hydroxybenzaldehyde with, for example, benzyl bromide in the presence of an alkali, and subjecting the resulting compound to the above-mentioned acetalization or thioacetalization reaction.

Here, specific synthesis examples of the compound represented by the above general formula are shown, but the present invention is not limited thereto.

(Synthesis Example 1) Product 1) 10.6 g of 4-penzyloxybenzaldehyde was dissolved in 150 ml of benzene, and 1,3-propanediol 4
．． About 0.5 g of p-1 toluenesulfonic acid was added, and the mixture was refluxed for 3 hours while the water produced was removed by azeotropy with benzene. The reaction solution was washed with a 10% aqueous sodium carbonate solution, dried over anhydrous sodium sulfate, and benzene was distilled off. The residue was recrystallized from a mixed solvent of n-hexane:benzene=10:1 to obtain 7.2 g of the desired product (white crystals).

Melting point: 88.5°C to 89.5°C.

(Synthesis Example 2) (Compound 9) 18.3 g of p-hydroxybenzaldehyde was dissolved in 200 ml of methyl ethyl ketone, and 22.8 g of potassium carbonate was dissolved.
23.2 g of g1α-chlorop-xylene was added, and the mixture was refluxed for 10 hours under a nitrogen stream.

Insoluble matters were removed by filtration, the solvent of the filtrate was distilled off, and the residue was distilled under reduced pressure to obtain 17.9 g of 4-(4-methylbenzyloxy)benzaldehyde (white crystals).

4-(4-methylbenzyloxy)benzaldehyde 7
．． 9g of benzene was dissolved in 100m of benzene, 2.7g of 2-mercaptoethanol, and about 0.5g of p-toluenesulfonic acid.
g was added thereto, and the mixture was refluxed for 3 hours while the produced water was removed by azeotropy with benzene. The reaction solution was washed with a 10% aqueous sodium carbonate solution, dried over anhydrous sodium sulfate, and benzene was distilled off.

The residue was recrystallized from a mixed solvent of n-hexane:benzene=10:1 to obtain 5.0 g of the desired product (white crystals). Melting point: 101°C to 102°C.

(Synthesis Example 3) Synthesis of 2-[4-(3-chlorobenzyloxy)phenyl]-1,3-dithiane (Compound 33) 18.3 g of p-hydroxybenzaldehyde was dissolved in 200 ml of methyl ethyl ketone, and 22.8 g of potassium carbonate was added. -24.2 g of chlorobenzyl chloride was added, and the mixture was refluxed for 8 hours under a nitrogen stream. Insoluble matter was removed by filtration, the solvent was distilled off from the filtrate, and 32.6 g of 4-(3-
Chlorobenzyloxy)benzaldehyde (white crystals)
I got it.

4-(3-chlorobenzyloxy)benzaldehyde 9
．． 9 g was dissolved in 150 ml of ethanol, 3.8 g of ethanedithiol was added and stirred, and about 1 g of boron trifluoride ethyl etherate was added dropwise under water cooling. White crystals were immediately deposited. The mixture was further stirred at room temperature for 1 hour. The crystals were collected by filtration, thoroughly washed with a 10% aqueous sodium carbonate solution and water, dried, and then recrystallized from ethanol to obtain 8.0 g of the desired product (white crystals). Melting point: 99°C to 100°C.

Next, a specific method for producing the heat-sensitive recording material according to the present invention will be described.

The heat-sensitive recording material according to the present invention is generally provided with a heat-sensitive recording layer mainly composed of an electron-donating, usually colorless or light-colored dye precursor and an electron-accepting compound on a support, and can be used with a thermal head, a thermal pen, or a laser beam. By heating the dye precursor with an electron-accepting compound, a recorded image is obtained by instantaneous reaction between the dye precursor and the electron-accepting compound.
It is disclosed in Publication No. 39 and the like. Further, pigments, sensitizers, antioxidants, anti-sticking agents and the like are added to the heat-sensitive recording layer as necessary.

The dye precursor used in the heat-sensitive recording material according to the present invention is not particularly limited as long as it is generally used in pressure-sensitive recording paper or heat-sensitive recording paper. Specific examples include (1) triarylmethane compounds 3,3-bis(p-dimethylaminophenyl) 6-dimethylaminophthalide (crystal violet lactone), 3,3-bis(p-dimethylamino phenyl)phthalide, 3-(p-dimethylaminophenyl')-3
- (1,2-dimethylindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)-3- (2
-methylindol-3-yl)phthalide, 3-(p-
dimethylaminophenyl)-3-(2-phenylindol-3-yl)phthalide, 3,3-bis(1,2-
dimethylindol-3-yl)-5-dimethylaminophthalide, 3,3-bis(1,2-dimethylindol-3-yl)-6-dimethylaminophthalide, 3,3-
Bis(9-ethylcarbazol-3-yl)-5-dimethylaminophthalide, 3,3-bis(2-phenylindol-3-yl)-5-dimethylaminophthalide, 3
-p-dimethylaminophenyl-3-(1-methylpyrrol-2-yl)-6-dimethylaminophthalide and the like.

(2) Diphenylmethane compounds 4.4°-bis(dimethylaminophenyl)benzhydrylbenzyl ether, N-chlorophenylleucoauramine, N-2.4.5-trichlorphenylleucoauramine, etc.

(3) Xanthene compounds Rhodamine B anilinolactam, Rhodamine B-p-chloroanilinolactam, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-7-octylaminofluorane, 3-diethylamino-7- Phenylfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-chloro-7-methylfluorane, 3-diethylamino-7-(3.4-dichloroanilino)fluorane, 3-diethylamino-7-
(2-chloroanilino)fluorane, 3-diethylamine-6-methyl-7-anilinofluorane, 3-(.N
monoethyl-N-tolyl)amino-6-methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3-(N-ethyl-N-tolyl)amino-6-methyl-7 -Phenethylfluorane, 3-jethylamino-7-(4-nitroanilino)fluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3-(N-methyl-N-probyl)amino-6
-Methyl-7-anilinofluorane, 3-(N-ethyl-N-isoamyl)amino-6-methyl-7-anilinofluorane, 3-(N-methyl-N-cyclohexyl)
Amino-6methyl-7-anilinofluorane, 3-(N
ethyl-N-tetrahydrofuryl)amino-6-methyl-7-anilinofluorane, etc.

(4) Thiazine-based compounds penzoyl icomethylene blue, p-nitropenzoyl icomethylene blue, etc.

(5) Spiro-based compounds 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3"-dichlorospirodinaphthopyran, 3-penzylspirodinaphthopyran, 3-methylnaphtho(3-methoxybenzo)subiropyran, 3- Provilsuvirobenzobilan etc.

These can be used alone or in combination of two or more.

The color developer is not particularly limited as long as it is an acidic substance commonly used in thermal paper. For example, polyvalent metal salts such as phenol derivatives, aromatic carboxylic acid derivatives, N,N'diarylthiourea derivatives, and zinc salts of organic compounds can be used. Also, particularly preferred are phenol derivatives, specifically p-phenylphenol, p-hydroxyacetophenone, 4-hydroxy-4゜-methyldiphenylsulfone, 4-hydroxy-4'-isoproboxy Diphenylsulfone, 4-hydroxy-4°-benzenesulfonyloxydiphenylsulfone, 1
, 1-bis(p-hydroxyphenyl)propane, 1,
1-bis(p-hydroxyphenyl)pentane, 1,1
-bis(p-hydroxyphenyl)hexane, 1,1-
Bis(p-hydroxyphenyl)cyclohexane, 2.
2-bis(p-hydroxyphenyl)propane, 2.2
-bis(p-hydroxyphenyl)hexane, 1,1-
Bis(p-hydroxyphenyl)-2-ethylhexane, 2,2-bis(3-chloro-4-hydroxyphenyl)propane, ■. 1-bis(p-hydroxyphenyl)
-1-phenylethane, 1. 3-G[2-(
p-hydroxyphenyl)-2-proyl]benzene,
1,3-di[2-(3,4-dihydroxyphenyl)
-2-propyl]benzene, 1,4-di(2-(p-
hydroxyphenyl)-2-proyl]benzene, 4,
4゜dihydroxydiphenyl ether, 4.4''-dihydroxydiphenyl sulfone, 3,3゜dichloro4
, 4゛-dihydroxydiphenylsulfone, 3.3"
-Diallyl-4,4°-dihydroxydiphenyl sulfone, 3,3°-dichloro-4.4'-dihydroxydiphenyl sulfide, 2,2-bis(4-hydroxyphenyl)methyl acetate, 2.2 -bis(4-hydroxyphenyl)butyl acetate, 4,4°-thiobis(2-
(t-butyl-5-methylphenol), benzyl p-hydroxybenzoate, chlorobenzyl p-hydroxybenzoate, dimethyl 4-hydroxyphthalate, benzyl gallate, stearyl gallate, salicylanilide, 5-chlorosalicylanilide, etc. .

Binders used in heat-sensitive recording materials include starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein,
Alkali salts of polyvinyl alcohol, modified polyvinyl alcohol, sodium polyacrylate, acrylic amide/acrylic ester copolymer, acrylic amide/acrylic ester/methacrylic acid ternary copolymer, styrene/maleic anhydride copolymer , water-soluble adhesives such as alkali salts of ethylene/maleic anhydride copolymers, polyvinyl acetate, polyurethane, polyacrylic esters, styrene/putadiene copolymers, acrylonitrile/putadiene copolymers, methyl acrylate/putadiene copolymers, etc. Examples include polymers and latexes such as ethylene/vinyl acetate copolymers.

In addition, N-
Waxes such as hydroxymethyl stearamide, stearamide, and valmitic acid amide, naphthol derivatives such as 2-penzyloxynaphthalene, biphenyl derivatives such as p-penzylbiphenyl and 4-allyloxybiphenyl, 1.2- Bis(3-methylphenoxy)
Polyether compounds such as ethane, 2.2'-bis(4-methoxyphenoxy) diethyl ether, bis(4-methoxyphenyl) ether, diphenyl carbonate, dibenzyl oxalate, bis(p-methylbenzyl) oxalate ester Carbonic acid or oxalic acid diester derivatives such as these can be added in combination.

Examples of the pigment include diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silicon oxide, aluminum hydroxide, urea-formalin resin, and the like.

In addition, higher fatty acid metal salts such as zinc stearate and calcium stearate, waxes such as paraffin, oxidized paraffin, polyethylene, oxidized polyethylene, stearic acid amide, and castor wax are used to prevent head wear and stickiness, as well as dioctyl sulfosuccinate. A dispersant such as sodium chloride, an ultraviolet absorber such as a penzophenone type or a penzotriazole type, a surfactant, a fluorescent dye, etc. are added as necessary.

As the support used in the present invention, paper is mainly used, but nonwoven fabric, plastic film, synthetic paper, metal foil, etc., or a composite sheet of a combination of these can also be used as desired. In addition, in the production of heat-sensitive recording materials, an overcoat layer is provided to protect the heat-sensitive recording layer, and an undercoat layer consisting of a single layer or multiple layers of pigment or resin is provided between the heat-sensitive recording layer and the support. Various known techniques can be used.

The coating amount of the heat-sensitive recording layer is determined by the amounts of the dye precursor and color developer that are responsible for color development, and is usually 0.1 to 1. ．． O
g/rrf is appropriate.

Further, the amount of the color developer added is 5 to 400% by weight based on the dye precursor, and a particularly preferable addition amount is 20 to 300% by weight.

The compound of the present invention is added in an amount of 5 to 400% by weight based on the color developer, and a particularly preferable addition amount is 20 to 300% by weight.

<Example> Next, the present invention will be explained in more detail with reference to Examples.

Note that all parts and percentages shown below are based on weight.

(Example 1) Preparation of heat-sensitive recording material (1) Preparation of heat-sensitive coating liquid Dye precursor 3-dibutylamino-6-methyl-7
- 35 parts of anilinofluorane and 80 parts of a 2.5% polyvinyl alcohol aqueous solution were ground in a ball mill for 24 hours to obtain a dye dispersion. Next, 40 parts of 2,2-bis(p-hydroxyphenyl)propane and 60 parts of a 2.5% polyvinyl alcohol aqueous solution were ground in a ball mill for 24 hours to obtain a color developer dispersion. 2-(4-penzyloxyphenyl)-1,3-dioxane (compound 1) 50 parts
, and 120 parts of a 5% polyvinyl alcohol aqueous solution for 24 hours in a ball mill to obtain a dispersion of the compound of the present invention.

After mixing the above three types of dispersions, the following were added and mixed well while stirring to prepare a heat-sensitive coating liquid.

50% calcium carbonate dispersion 100 parts 40% zinc stearate dispersion 25 parts 10% polyvinyl alcohol aqueous solution 185 parts water
280 copies (2) Preparation of heat-sensitive coated paper A coating liquid consisting of the following composition is smeared on base paper with a basis weight of 40 g/rd to a solid content of 9 g/rd, and dried to create heat-sensitive coated paper. did.

Calcined kaolin 100 parts Styrene-butadiene latex 50% aqueous dispersion 24 parts water
200 copies (3) Preparation of heat-sensitive recording material The heat-sensitive coating liquid prepared in (1) was smeared on the surface of the heat-sensitive coating paper prepared in (2) to a solid content coating amount of 4 glrd, and dried. A thermosensitive recording material was created.

(Examples 2 to 7) 2-(4-penzyloxyphenyl) in Example 1
-2(4-penzyloxyphenyl)-1,3-dithiolane (Example 2: Compound 3), 2-[4-(4-methylbenzyloxy)] instead of -1,3-dioxane
phenyl]-1,3oxathiolane (Example 3: Compound 9), 2[4-(3-methylbenzyloxy)phenyl]1,3-dithiolane (Example 4; Compound 15), 2-
[4-(4-methoxybenzyloxy)phenyl]
-1.3-dithiolane (Example 5: Compound 2 1),
2-[4-(4-chloropenzyloxy)phenyl]
-1,3-dithiolane (Example 6; Compound 27), 2
= [4-(3-chlorobenzyloxy)phenyl]
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that -1,3-dithiolane (Example 7: Compound 32) was used.

(Comparative Example 1) 2-(4-penzyloxyphenyl) in Example 1
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that -1,3-dioxane was omitted.

(Comparative Example 2) 2-(4-penzyloxyphenyl) in Example 1
A heat-sensitive recording material was prepared in the same manner as in the example except that N-hydroxymethylstearamide was used instead of -1,3-dioxane.

(Evaluation) The heat-sensitive recording materials obtained in Examples 1 to 7 and Comparative Examples 1 and 2 were calendered so that the smoothness of the heat-sensitive coated surface was 400 to 500 seconds, and then subjected to a facsimile testing machine manufactured by Okura Electric Co., Ltd. A printing test was conducted using TH-PMD.

A thermal head with a dot density of 8 dots/mm and a head resistance of 85 Ω was used, with a head voltage of 12 V and a pulse width of 0.
Printing was performed by applying electricity for 6 and 07 milliseconds, and the color density was measured using a Macbeth RD-918 type reflection densitometer. The results are shown in the table below.

<Effects> As is clear from the examples, by incorporating the compound of the present invention, it was possible to obtain a heat-sensitive recording material with excellent thermal responsiveness, high optical density, and high color development sensitivity with the same printing energy. .

July 11, 2007

Claims (1)

[Claims] 1. A heat-sensitive recording material containing a normally colorless or light-colored dye precursor and an electron-accepting compound that reacts with the dye precursor when heated to cause the dye precursor to develop a color, in which a compound represented by the following general formula is used. A heat-sensitive recording material characterized by containing: General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, in the above formula, X and Y represent oxygen or sulfur atoms,
They may be the same or different. Further, Z forms an alkylene chain having 2 or more carbon atoms, and may have an alkyl group side chain. Further, Ar represents a substituted or unsubstituted aryl group. )