JPH05309942A - Thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a highly water-resistant thermal recording material reduced in background fog under a high temp. and high humidity condition by providing a thermal color forming layer containing a colorless or light-colored electron donating dye, an acidic substance and a specific epoxy resin on a support. CONSTITUTION:Predetermined amounts of a colorless or light-colored electron donating color forming dye, an acidic substance and an epoxy resin represented by formula I (wherein n is an integer of 1-25) are separately ground and dispersed along with a binder by a dispersing machine such as a ball mill and the obtained dispersions are mixed to prepare a coating solution which is, in turn, applied to a support such as paper or a plastic sheet and dried to form a thermal color forming layer to produce a thermal recording material. If necessary, an intermediate layer may be provided between the thermal color forming layer and the support or an overcoat layer may be provided on the thermal color forming layer. The obtained thermal recording material is reduced in background fog under a high temp. and high humidity condition and imparts a developed color image excellent in preservability.

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 excellent in storage stability of color images and whiteness of background.

[0002]

2. Description of the Related Art A heat-sensitive recording material using a colorless or light-colored coloring substance and a color-developing substance capable of coloring the coloring substance under heat is disclosed in JP-B-43-4160 and JP-B-451403.
It was announced in Issue 9 and has been put to practical use. In general, a heat-sensitive recording material is prepared by separately dispersing a leuco dye and a developer such as a phenolic substance in the form of fine particles, and then mixing the two, and then adding a binder, a sensitizer, a filler, a lubricant, etc. It forms a coating liquid by adding additives, and it is applied to a support such as paper, film, synthetic paper, etc. It is colored by a chemical reaction that occurs when one or both of the leuco dye and the color developer melt and contact by heating. In order to obtain a record, a sheet-shaped heat-sensitive recording material is usually prepared. A thermal printer or the like having a built-in thermal head is used for color development of such a thermal recording sheet. Compared to other recording methods, this heat-sensitive recording method is (1) no noise is generated during recording, (2) no need for developing and fixing, (3) maintenance-free, (4)
It is widely used in the field of facsimiles, output of computers, printers such as calculators, recorders for medical measurement, ticket vending machines, thermosensitive recording labels, etc. due to the fact that machines are relatively inexpensive. ..

Among these fields of use, labels are being used with the expansion of POS systems in retail stores, supermarkets, etc., and their use for tickets for automated systems for station affairs is increasing. However, their use is a major drawback in that the color image disappears or fades due to contact with plastic sheets or water wetting.

As a method for solving such a drawback, a method of coating an aqueous emulsion of a resin having chemical resistance on the heat-sensitive recording layer (Japanese Patent Laid-Open No. 128-347347) and a method of coating a water-soluble polymer compound such as polyvinyl alcohol. (Actual development No. 50-125354), or a method of using a bisphenol derivative for the purpose of improving water resistance and storability of color images (JP-A-57-195691, JP-A-57-20519).
1), a method using a novolac epoxy resin (Japanese Patent Application Laid-Open No. 2-289378), etc. have been proposed, but a sufficiently satisfactory effect has not been obtained.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art. That is,
To provide a heat-sensitive recording material having high water resistance and high plasticizer resistance, which hardly causes discoloration or discoloration due to water wetting of a colored image or contact with plastic films and the like, has little background fog under high temperature and high humidity conditions. It is in.

[0006]

Means for Solving the Problems The present inventors have completed the present invention as a result of various studies to achieve the above object. That is, the present invention is characterized in that a color-forming recording material comprising a colorless or light-colored electron-donating color-forming dye and an acidic substance contains at least one epoxy resin represented by the formula (1). A thermal recording material is provided.

[0007]

[Chemical 2]

(In the formula (1), n represents an integer of 1 to 25.) Bisphenol A represented by the formula (2) and epichlorohydrin are mixed with epichlorohydrin / bisphenol A / caustic soda in the presence of caustic soda. By adjusting the ratio and reacting, a desired n of the epoxy resin represented by the formula (1) can be produced.

[0009]

[Chemical 3]

Further, in the epoxy resin represented by the formula (1), a low molecular weight epoxy resin in which n is less than 1 and the bisphenol A represented by the formula (2) are mixed with the low molecular weight epoxy resin /
By adjusting the molar ratio of bisphenol A and reacting it, an epoxy resin in which n is 1 to 25 in the formula (1) can be produced. Among the epoxy resins of the formula (1), preferred are those having a softening point of 60 to 150 degrees, particularly preferably 80 to 120 degrees. If the softening point is too high, the effect of improving the preservability may be lowered, and if the softening point is too low, the whiteness of the thermal recording paper may be lowered. The epoxy resin of the formula (1) can be contained not only in the thermosensitive coloring layer but also in an intermediate layer provided between the support and the thermosensitive coloring layer or in a protective layer provided on the thermosensitive coloring layer. is there. As a result, a heat-sensitive recording paper having improved plasticizer resistance and oil resistance and free from background fog can be obtained. In this case, the epoxy resin of the formula (1) is 1-50% by weight based on the dry weight of the intermediate layer or the protective layer.
It is included.

In the heat-sensitive recording material of the present invention, the following (A) color-forming compound, (B) color-developing compound,
(C) A thermosensitive coloring layer is prepared with a binder and optionally a filler, a heat-fusible compound, a surfactant, etc.,
The compound represented by the formula (1) is contained in the thermosensitive coloring layer in an amount of 1-50.
The weight percentage is preferably 2 to 30 weight percent.

(A) Examples of color-forming compounds Fluoran compounds, triarylmethane compounds, spiropyran compounds, diphenylmethane compounds, thiazine compounds, lactam compounds, fluorene compounds and the like are mentioned, and specific examples thereof include The following compounds may be mentioned.

Fluoran compounds; 2-anilino-3-
Methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-dibutylaminofluorane, 2-
Anilino-3-methyl-6-dipentylaminofluorane, 2-anilino-3-methyl-6- (N-methyl-N
-Cyclohexylamino) fluorane, 2-anilino-
3-Methyl-6- (N-ethyl-N-isopentylamino) fluorane, 2- (p-chloroanilino) -3-methyl-6-diethylaminofluorane, 2- (p-fluoroanilino) -3-methyl -6-Diethylaminofluorane, 2-anilino-3-methyl-6- (p-toluidinoethylamino) fluorane, 2- (p-toluidino) -3-methyl-6-diethylaminofluorane, 2
-(O-chloroanilino) -6-diethylaminofluorane, 2- (o-chloroanilino) -6-dibutylaminofluorane, 2- (o-fluoroanilino) -6-diethylaminofluorane, 2- (o-fluoro Anilino) -6-dibutylaminofluorane, 2-anilino-
3-methyl-6-piperidinofluorane, 2-anilino-3-methyl-6-pyrrolidinofluorane, 2-ethoxyethylamino-3-chloro-6-diethylaminofluorane, 2-anilino-3-chloro -6-diethylaminofluorane, 2-chloro-6-diethylaminofluorane, 2-methyl-6-diethylaminofluorane, 2
-Anilino-3-methyl-6- (N-isobutyl-N-
Ethylamino) fluorane, 2-anilino-3-methyl-6-((N-ethyl-N- (ethoxypropyl) amino) fluorane, 2-anilino-3-methyl-6- (N
-Ethyl-N-hexylamino) fluorane, etc.,

Triarylmethane compound; 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) ) −
Spiropyran-based compounds such as 3- (1,2-dimethylaminoindole) -3-isophthalide; 3-methyl-3-spirodinaphthopyran, -1,3,3-trimethyl-6-nitro-
8'-methoxyspiro (indoline-2,2'-benzopyran) and the like, diphenylmethane compounds; N-halophenyl-leukoauramine and the like,

Thiazine compounds; benzoyl leuco methylene blue, etc., lactam compounds, rhodamine-B-anilinolactam, etc., fluorene compounds, 3,6-bis (dimethylamino)
Fluorene spiro (9,3 ')-6-'dimethylaminophthalide, [3,6-bis (dimethylamino) fluorenspiro (9,3')-6'-pyrrolidinophthalide],
[3-Dimethylamino-6-diethylaminofluorenspiro (9,3 ′)-6′-pyrrolidinophthalide] and the like can be mentioned. These color forming compounds may be used alone or in combination.

(B) Examples of color-developing compounds α-naphthol, β-naphthol, p-octylphenol, 4-t-octylphenol, pt-butylphenol, p-phenylphenol, 1,1'-bis (p- Hydroxyphenyl) propane, 2,2-bis (p-hydroxyphenyl) propane, 2,2′-bis (p-hydroxyphenyl) butane, 1,1′-bis (p-hydroxyphenyl) cyclohexane, 4,4 ′
-Thiobisphenol, 4,4'-cyclohexylidene diphenol, 4,4'-sulfonyldiphenol,
4,4'-sulfonyl-bis (2-allylphenol), 2,2'-bis (2,5-dibromo-4-hydroxyphenyl) propane, 4,4'-isopropylidenebis (2-t-butylphenol) , 2,2'-methylenebis (4-chlorophenol), 4-hydroxy-
4'-isopropoxydiphenyl sulfone, bis (4-
Phenolic compounds such as methyl hydroxyphenyl) acetate, butyl bis (4-hydroxyphenyl) acetate, and benzyl bis (4-hydroxyphenyl) acetate, benzyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, 4-hydroxyphthalic acid Dibenzyl, dimethyl 4-hydroxyphthalate, ethyl 5-hydroxyisophthalate, 3,5-di-t-butylsalicylic acid, 3,5-di-
Examples thereof include aromatic carboxylic acid derivatives such as α-methylbenzyl salicylic acid, aromatic carboxylic acids and polyvalent metal salts thereof.

(C) Examples of binders Methylcellulose, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, sodium carboxymethylcellulose, cellulose, polyvinyl alcohol (PVA), carboxy group-modified polyvinyl alcohol, sulfonic acid group-modified polyvinyl alcohol, polyvinylpyrrolidone, poly Water-soluble acrylamide, polyacrylic acid, starch and its derivatives, casein, gelatin, isoprene rubber, alkali salt of styrene / maleic anhydride copolymer, alkali salt of iso (or diiso) butylene / maleic anhydride copolymer, etc. Or polyvinyl acetate, vinyl chloride / vinyl acetate copolymer, polystyrene, polyacrylate, polyurethane,
Styrene / butadiene (SB) copolymer, carboxylated styrene / butadiene (SB) copolymer, styrene /
A water-soluble emulsion such as a butadiene / acrylic acid type copolymer or a composite particle of colloidal silica and an acrylic resin is used.

Examples of other additives Examples of fillers include calcium carbonate, magnesium carbonate, magnesium oxide, silica, white carbon, talc, clay, alumina, magnesium hydroxide, aluminum hydroxide, aluminum oxide, barium sulfate and polystyrene. Resin, urea-formalin resin and the like.

Examples of the heat-fusible compound include waxes such as animal and vegetable wax, polyethylene wax, and synthetic wax, higher fatty acids, higher fatty acid amides, higher fatty acid metal salts, acetylated aromatic amines, aromatic ether compounds, and aromatics. It is possible to use those which are solid at room temperature and have a melting point of about 80 ° C. or higher, such as group sulfonic acid esters and biphenyl derivatives. Specific examples of these compounds include:
Caproic acid amide, capric acid amide, palmitic acid amide, stearic acid amide, oleic acid amide, erucic acid amide, linoleic acid amide, N-methylstearic acid amide, stearic acid anilide, N-methyloleic acid amide, benzanilide, linoleic acid Anilid, N-
Ethylcapric acid amide, N-butyllauric acid amide, N-octadecylacetamide, N-oleinacetamide, N-oleinbenzamide, N-stearylcyclohexylamide, erucic acid amide, methylolbehenic acid amide, methylolstearic acid amide, methylenebisstearic acid Acid amide, ethylenebisstearic acid amide, p-acetotoluidide, polyethylene glycol, 1-benzyloxynaphthalene, 2-benzyloxynaphthalene, 1-hydroxynaphthoic acid phenyl ester, 1,2-diphenoxyethane, 1,4-diphenoxy Butane, 1,2-bis (3-methylphenoxy) ethane, 1,2-bis (4-methoxyphenoxy) ethane, 1,2-bis (3,4-dimethylphenyl) ethane, 1-phenoxy-2 (4-chlorophenoxy) ethane, 1-phenoxy-2- (4-methoxyphenoxy) ethane, 1- (2-methylphenoxy) -2- (4
-Methoxyphenoxy) ethane, terephthalic acid dibenzyl ester, oxalic acid dibenzyl ester, oxalic acid di (4-methylbenzyl) ester, p-benzyloxybenzoic acid benzyl ester, p-benzylbiphenyl,
m-terphenyl, 1,5-bis (p-methoxyphenoxy) -3-oxa-pentane, 1,4-bis (2-vinyloxyethoxy) benzene, p-biphenyl-p-
Examples include compounds such as tolyl ether, benzyl-p-methylthiophenol, phenylmesitylene sulfonate, and 4-methylphenylmesitylene sulfonate. In addition, lubricants such as zinc stearate, calcium stearate and aluminum stearate, various surfactants, antifoaming agents and the like are added as necessary.

The heat-sensitive recording material of the present invention is prepared using the above-mentioned material, for example, by the following method. That is, according to a conventional method, first, a color-forming compound, a color-developing compound, and a compound represented by the formula (1) are separately added together with a binder or, if necessary, other additives, in a ball mill, attritor,
After crushing and dispersing with a disperser such as a sand mill (the compound of formula (1) may be mixed with a color-forming compound or a color-developing compound in advance for dispersion), and mixed to form a thermosensitive color-forming layer coating liquid. Prepared and coated on a support such as paper, plastic sheet or synthetic paper by a bar coater, a blade coater or the like so that the dry weight is usually 1 to 20 g / m ² (ratio of the color-forming compound and the color-developing compound). Is usually 1: 1 to 1:10 by dry weight ratio) to obtain the heat-sensitive recording material of the present invention.

If necessary, an intermediate layer may be provided between the thermosensitive color developing layer and the support, or an overcoat layer may be provided on the thermosensitive color developing layer. The heat-sensitive recording material of the present invention containing the compound of the formula (1) has less background fog at high temperature and high humidity, and has better storability of color images (plasticizer resistance, water resistance, heat resistance) than those conventionally known. , Light resistance) is excellent.

[0022]

EXAMPLES The present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. In the examples, "part" indicates part by weight.

Example 1 A mixture having the following composition was pulverized for 30 minutes using a sand grinder, and liquids [A], [B] and [C] were respectively obtained.
A liquid was prepared. Liquid [A]: 2-anilino-3-methyl-6-25 parts Dibutylaminofluorane 25% PVA aqueous solution 20 parts Water 55 parts [B] liquid: Bisphenol A 8 parts 4-Methylphenylmesitylene sulfonate 8 parts Calcium carbonate 13.5 parts Carboxylated SB latex (50%) 7 parts 25% PVA aqueous solution 5 parts Water 58.5 parts [C] liquid: Epoxy resin No. 1 25 parts 25% PVA aqueous solution 20 parts water 55 parts Epoxy resin No. 1 used here. No. 1 is an epoxy resin having a softening point of 98 ° C. and an average n of the general formula (1) of 5.4 and an epoxy equivalent of 920.

Next, the above [A] solution: [B] solution: [C] solution = 6 parts: 74 parts: 20 parts are mixed to prepare a thermosensitive color developing layer coating solution having a basis weight of 50 g / m ² . 3 on a fine paper
The coating was carried out so that the coating amount was 0 g / m ^2, and the coating was dried to provide a thermosensitive coloring layer. Further, a 10% PVA aqueous solution was applied and dried on the thermosensitive coloring layer so that the coating amount after drying was 3 g / m ² to obtain a thermosensitive recording material of the present invention.

Example 2 Liquid [D] having the following crushing composition in place of the liquid [A] in Example 1 [D] liquid: 2-o-fluoroanilino-6-25 parts dibutylaminofluorane 25% PVA aqueous solution 20 parts Water 55 parts [D] liquid: [B] liquid: [C] liquid: water = 6 parts: 74
Parts: 10 parts: mixed at a ratio of 10 parts to prepare a thermosensitive color developing layer coating liquid, and the liquid amount is 30 g on a high-quality paper having a basis weight of 50 g / m ^2.
The coating was performed so that the coating amount would be / m ² and the coating was dried to provide a thermosensitive coloring layer. Further, a 10% PVA aqueous solution was applied and dried on the thermosensitive coloring layer so that the coating amount after drying was 3 g / m ² to obtain a thermosensitive recording material of the present invention.

Example 3 In Example 1, the epoxy resin No. 1 of the liquid [C] was used. Epoxy resin No. 1 instead of No. 1 2 was used to obtain a heat-sensitive material of the present invention in the same manner as in Example 1. Epoxy resin No. 2 is the formula (1)
Is an epoxy resin having a softening point of 68 ° C. and an average n of 2.1 and an epoxy equivalent of 475.

Example 4 In Example 1, the epoxy resin No. 1 of the liquid [C] was used. Epoxy resin No. 1 instead of No. 1 3 was used in the same manner as in Example 1 to obtain a heat-sensitive recording material of the present invention. Epoxy resin No. 3 is an epoxy resin having a softening point of 83 ° C. and an average n of the formula (1) of 3.4 and an epoxy equivalent of 650.

Example 5 In Example 1, the epoxy resin No. 1 of the liquid [C] was used. Epoxy resin No. 4 instead of 1. Was used in the same manner as in Example 1 to obtain a heat-sensitive material of the present invention. Epoxy resin No. 4 is formula (1)
Is an epoxy resin having an average n of 3.7 and an epoxy equivalent of 700 and a softening point of 89 ° C.

Example 6 In Example 1, the epoxy resin No. 1 of the liquid [C] was used. Epoxy resin No. 5 instead of 1. Was used to obtain a thermosensitive recording material of the present invention in the same manner as in Example 1. Epoxy resin No. 5 has an average n of the formula (1) of 12.6 and an epoxy equivalent of 2000.
Is an epoxy resin having a softening point of 128 ° C.

Example 7 In Example 1, the epoxy resin No. 1 of the liquid [C] was used. Epoxy resin No. 6 instead of 1. Was used in the same manner as in Example 1 to obtain a heat-sensitive material of the present invention. Epoxy resin No. 6 is the formula (1)
Is an epoxy resin having a softening point of 148 ° C. and an average n of 19.5 and an epoxy equivalent of 2850.

Example 8 The heat-sensitive material of the present invention was prepared in the same manner as in Example 1 except that 4,4'-sulfonylbis (2-allylphenol) was used in place of bisphenol A in the liquid (B) of Example 1. A recording material was obtained.

Example 9 Instead of bisphenol A in the liquid (B) of Example 1, 4
A thermal recording material of the present invention was obtained in the same manner as in Example 1 except that -hydroxy-4'-isopropoxydiphenyl sulfone was used.

Example 10 A thermosensitive recording material of the present invention was obtained in the same manner as in Example 1 except that benzyl bis (4-hydroxyphenyl) acetate was used instead of bisphenol A in the liquid (B) of Example 1. It was

Example 11 2-anilino-3-methyl-6 in the liquid (A) of Example 1
2-anilino-instead of dibutylaminofluorane
A thermal recording material of the present invention was obtained in the same manner as in Example 1 except that 3-methyl-6- (N-ethyl-N-isopentylamino) fluorane was used.

Example 12 A thermosensitive recording material of the present invention was obtained in the same manner as in Example 1 except that methylolstearic acid amide was used instead of 4-methylphenylmesitylene sulfonate in the liquid (B) of Example 1. It was

Example 13 A thermosensitive recording material of the present invention was obtained in the same manner as in Example 1 except that p-benzylbiphenyl was used in place of 4-methylphenylmesitylene sulfonate in the liquid (B) of Example 1. It was

Comparative Example 1 A thermosensitive recording material was obtained in the same manner as in Example 1 except that the liquid [C] was not used.

Comparative Example 2 Epoxy resin No. 1 of the liquid [C] in Example 1 was used. Cresol novolac type epoxy resin instead of 1; Nippon Kayaku Co., Ltd .; trade name EOCN-104S (softening point 94 ° C.)
A thermosensitive recording material was obtained in the same manner as in Example 1.

Comparative Example 3 A cresol novolac type epoxy resin Asahi Kasei Co., Ltd .; trade name ECN-299 (softening point 97 ° C.) was used in place of the epoxy resin No1 of the liquid [C] in Example 1. Similarly, a heat sensitive material was obtained.

Using the heat-sensitive recording material of the present invention and the heat-sensitive recording material for comparison obtained as described above, the following quality evaluation test was carried out.

Table 1 Results of quality performance test Background 1) Color density 2) Heat resistance 3) Water resistance 4) Background image area Image area Example 1 0.06 1.32 0.07 1.32 1.06 Example 2 0.05 1.29 0.07 1.29 1.03 Example 3 0.06 1.35 0.07 1.35 1.08 Example 4 0.06 1.35 0.07 1.351 0.07 Example 5 0.06 1.34 0.07 1.34 1.08 Example 6 0.06 1.31 0.07 1.31 1.11 Example 7 0.06 1.30 0.07 1.30 1.10 Example 8 0.06 1.43 0.07 1.43 1.40 Example 9 0.05 1.46 0.06 1.46 1.31 Example 10 0.05 1. 37 0.06 1.37 1.29 Example 11 0.06 1.42 0.07 1.42 1.20 Implementation 12 0.05 1.35 0.06 1.35 1.20 Example 13 0.05 1.32 0.07 1.32 1.06 Comparative Example 1 0.06 1.36 0.07 1.220 .68 Comparative Example 2 0.08 1.26 0.25 1.26 0.88 Comparative Example 3 0.08 1.25 0.22 1.25 0.88

Table 2 Quality performance test results Moisture resistance 5) Plasticizer resistance 6) Light resistance 7) Background image area Image area Image background Image area Example 1 0.07 1.32 1.29 △ △ Example 2 0.07 1.29 1.26 △ △ Example 3 0.07 1.35 1.32 △ △ Example 4 0.07 1.35 1.32 △ △ Example 5 0.07 1.34 1. 31 Δ Δ Example 6 0.07 1.31 1.30 1.30 Δ Δ Example 7 0.07 1.30 1.29 Δ Δ Example 8 0.07 1.43 1.43 Δ Δ Example 9 0. 06 1.46 1.43 △ △ Example 10 0.06 1.37 1.33 △ △ Example 11 0.07 1.42 1.38 △ △ Example 12 0.06 1.35 1.30 △ △ Example 13 0.07 1.32 1.29 △ △ Comparative Example 1 0.07 1.29 0.95 △ △ Ratio Example 2 0.20 1.23 1.20 × ×× Comparative Example 3 0.15 1.23 1.18 × ××

1) Background The value (reflection density) of the uncolored portion of the sample measured by a Macbeth reflection densitometer RD-914 type. 2) Image Density The value obtained by measuring the density of a sample printed with a thermal printer (D-805P) manufactured by Ishida Koki Co., Ltd. using a Macbeth reflection densitometer RD-914 type.

3) Heat resistance The respective densities of the unprinted part and the sample printed by the thermal test printer were left in a thermostat at 60 ° C. for 24 hours, and the respective densities were measured by the Macbeth reflection densitometer. 4) Water resistance A value measured by the above Macbeth reflection densitometer after immersing a sample printed by the above thermal test printer in tap water at room temperature for 2 hours and air drying.

5) Moisture resistance The unprinted area and the sample printed by the thermal test printer were left in a thermo-hygrostat at 40 ° C. and 90% relative humidity for 24 hours, and the respective densities were measured by the Macbeth reflection densitometer. The measured value. 6) Plasticizer resistance A sample printed with the above thermal test printer was sandwiched from both sides with a PVC wrap film and left at 25 ° C. for 24 hours under a load of 30 g / cm ² , and the printed part was measured with the above Macbeth reflection densitometer. value.

7) Light resistance The unprinted part and the sample printed by the above thermal test printer were subjected to 1 using a fluorescent lamp.
The discoloration and fading of each sample was visually evaluated after irradiation for 100 hours under an illumination of 10,000 lux. ○ Insignificant discoloration or fading is not observed. △: Some discoloration or fading is observed. Marked by discoloration and fading. XX mark Discoloration or fading is remarkable.

As can be seen from Tables 1 and 2, the heat-sensitive recording material of the present invention is less heat-resistant and less moisture-resistant than the heat-sensitive recording material for comparison and has less background fog in the unprinted area, and the color density of the printed area. The decrease of is also small. It also gives a colored image having good water resistance, plasticizer resistance and light resistance.

[0048]

EFFECT OF THE INVENTION The heat-sensitive recording material of the present invention causes less background fog in the unprinted part under high heat and high humidity, and less reduction in color density of the printed part. Further, a heat-sensitive recording material which gives a colored image having good water resistance, plasticizer resistance and light resistance was obtained.

Claims (1)

[Claims] 1. A color-forming recording material comprising a colorless or light-colored electron-donating color-forming dye and an acidic substance, containing at least one epoxy resin represented by the formula (1). Thermosensitive recording material. [Chemical 1] (In the formula (1), n represents an integer of 1 to 25.)