JP2848544B2 - 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 heat-sensitive recording material, and more particularly to a heat-sensitive recording material having excellent storage stability of a color image.

[0002]

2. Description of the Related Art A heat-sensitive recording material using a colorless or light-colored color-forming substance and a color-developing substance capable of coloring the color-forming substance when heated is disclosed in JP-B-43-4160 and JP-B-45-14039.
And has been widely used. In general, a thermosensitive recording material is obtained by separately dispersing a developer such as a leuco dye and a phenolic substance into fine particles, and then mixing both.
Additives such as binders, sensitizers, fillers, lubricants, etc. are added to this to form a coating solution, which is applied to a support such as paper, film, synthetic paper, etc., and heated to produce a leuco dye and a developer. One or both of them is used to obtain a color recording by a chemical reaction caused by melting and contacting, and usually a sheet-like heat-sensitive recording material is prepared. A thermal printer with a built-in thermal head or the like is used for coloring the heat-sensitive recording sheet. Compared with other recording methods, this thermal recording method (1) produces no noise during recording, (2) does not require development and fixing,
(3) Maintenance-free. (4) Facsimile field, computer output, printer field such as calculator, etc.
It is widely used in the field of recorders for medical measurement, the field of automatic ticket vending machines, the field of heat-sensitive recording labels, and the like.

[0003] Among these fields of use, labels are increasing with the expansion of POS systems such as retail stores and supermarkets, and their use is increasing for tickets for station automation systems. However, a major drawback in their use is that the color image disappears or discolors due to contact with plastic sheets or wetness of water.

[0004] As a method for solving such a drawback, a method of applying an aqueous emulsion of a resin having chemical resistance on a heat-sensitive recording layer (Japanese Patent Laid-Open No. 54-128347), and a method of applying a water-soluble polymer compound such as polyvinyl alcohol. (Japanese Utility Model Application Laid-Open No. 50-125354), and a method of using a bisphenol derivative for the purpose of enhancing water resistance and preservation of a color image (JP-A-57-195691, JP-A-57-205191).
However, satisfactory effects have not been obtained.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the disadvantages of the prior art as described above. That is,
No color erasure or fading due to wetness of the color image or contact with plastic films or the like does not occur. It is an object of the present invention to provide a heat-sensitive recording material having high water resistance and high plasticizer resistance.

[0006]

Means for Solving the Problems The present inventors have made various studies to achieve the above object, and as a result, completed the present invention. That is, the present invention provides a thermosensitive recording material characterized in that the coloring layer contains a hydrogenated terpene polymer or a hydrogenated terpene-phenol copolymer.

The present invention will be described in detail. In the present invention, the hydrogenated terpene polymer to be contained in the color-forming layer is obtained, for example, by polymerizing α-pinene and β-pinene at a low temperature (for example, −15 ° C.) in the presence of aluminum chloride. It is obtained by hydrogenating a terpene polymer (terpene resin) by an ordinary method. Its structure has not been sufficiently elucidated, but has, for example, the following structure.

[0008]

Embedded image In the formulas (1), (2) and (3), n represents an integer of 3 to 10.

The hydrogenated terpene-phenol copolymer is a terpene-phenol obtained by copolymerizing phenol with α-pinene, β-pinene or the like in the presence of a Friedel-craft type catalyst. It is obtained by hydrogenating a copolymer by a conventional method. Its structure has not been sufficiently elucidated, but it is considered to have, for example, the following structure.

[0010]

Embedded image In the formula (4), m represents an integer of 2 to 6.

In the heat-sensitive recording material of the present invention, (A) a color-forming compound, (B) a color-developing compound,
(C) A thermosensitive coloring layer is prepared by using a binder and other necessary fillers, a heat-fusible compound, a surfactant, and the like, and the hydrogenated terpene polymer or the hydrogenated terpene-phenol copolymer is prepared from the thermosensitive coloring layer. It is contained in an amount of 1 to 50% by weight, preferably 5 to 30% by weight.

(A) Examples of color-forming compounds: Fluorane compounds, triarylmethane compounds, spiropyran compounds, diphenylmethane compounds, thiazine compounds, lactam compounds, fluorene compounds, and the like. For example, the following compounds may be mentioned.

Fluoran compound; 2-aniline-3-
Methyl-6-diethylaminofluoran, 2-anilino-3-methyl-6- (N-methyl-N-cyclohexylamino) -fluoran, 2-anilino-3-methyl-6
-(N-ethyl-N-isopentylamino) fluoran, 2-anilino-3-methyl-6-dibutylaminofluoran, 2- (p-chloroanilino) -3-methyl-
6-diethylaminofluoran, 2- (p-fluoroanilino) -3-methyl-6-diethylaminofluoran, 2-anilino-3-methyl-6- (p-toluidinoethylamino) fluoran, 2- ( p-toluidino)-
3-methyl-6-diethylaminofluoran, 2- (o
-Chloroanilino) -6-dibutylaminofluoran,
2- (o-fluoroanilino-6-diethylaminofluoran, 2- (o-fluoroanilino) -6-dibutylaminofluoran, 2-anilino-3-methyl-6-piperidinofluoran, 2- Anilino-3-methyl-6
Pyrrolidinofluoran, 2-ethoxyethylamino-3
-Chloro-6-diethylaminofluoran, 2-anilino-3-chloro-6-diethylfluoran, 2-chloro-6-diethylaminofluoran, 2-methyl-6-diethylaminofluoran and the like.

Triarylmethane compounds; 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone), 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) -3-
Spiropyran compounds such as (1,2-dimethylaminoindole-3-) isophthalide; 3-methyl-3-spirodinaphthopyran, 1,3,3-trimethyl-6
Nitro-8'-methoxyspiro (indoline-2,2 '
-Benzopyran); diphenylmethane compounds; N
-Halophenyl-leuco auramine, etc.

Thiazine compounds; lactam compounds such as benzoylleucomethylene blue; rhodamine-B-
Fluorene compounds such as anilinolactam; 3,6-
Bis (dimethylamino) fluorenespiro (9,3 ')
-6'-dimethylaminophthalide, [3,6-bis (dimethylamino) fluorenespiro (9,3 ')-6'-
Pyrrolidinophthalide], [3-dimethylamino-6-diethylaminofluorenespiro (9,3 ')-6'-pyrrolidinophthalide] and the like. These coloring compounds are used alone or in combination.

(B) Color-developing compounds α-naphthol, β-naphthol, p-octylphenol, 4-t-octylphenol, pt-butylphenol, p-phenylphenol, 1,1′-bis (p-hydroxy Phenyl) propane, 2,2′-bis (p-hydroxyphenyl) propane, 2,2′-bis (p-hydroxyphenyl) butane, 1,1′-bis (p-hydroxyphenyl) cyclohexane, 4,4 '
-Thiobisphenol, 4,4'-cyclohexylidenediphenol, 4,4'-sulfonyldiphenol,
4,4'-sulfonyl-bis (2-allylphenol), 2,2'-bis (2,5-dibromo-4-hydroxyphenyl) propane, 4,4'-isopropylidenebis (2-t-butylphenol ), Phenolic compounds such as 2,2'-methylenebis (4-chlorophenol), benzyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, dibenzyl 4-hydroxyphthalate,
Dimethyl 4-hydroxyphthalate, ethyl 5-hydroxyisophthalate, 3,5-di-t-butylsalicylic acid,
Examples thereof include aromatic carboxylic acid derivatives such as 3,5-di-α-methylbenzyl salicylic acid, aromatic carboxylic acids and polyvalent metal salts thereof.

(C) Binder Methylcellulose, methoxycellulose, hydroxyethylcellulose, carboxymethyl, sodium carboxymethylcellulose, cellulose, polyvinyl alcohol (PVA), carboxy group-modified polyvinyl alcohol, sulfonic acid group-modified polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, Polyacrylic acid,
Water-soluble or polyvinyl acetate such as starch and its derivatives, casein, gelatin water-soluble isoprene rubber, styrene / maleic anhydride copolymer alkali salt iso (or diiso) butylene / maleic anhydride copolymer alkali salt , Vinyl chloride / vinyl acetate copolymer, polystyrene, polyacrylate, polyurethane, styrene / butadiene (SB) copolymer, carboxylated styrene / butadiene (SB) copolymer, styrene / butadiene / acrylic acid copolymer For example, a water-soluble emulsion such as a composite particle of a 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 waxes, polyethylene waxes and synthetic waxes, higher fatty acids, higher fatty acid amides, higher fatty acid metal salts, acetylated aromatic amines, aromatic ether compounds, biphenyls. Derivatives and the like that are solid at ordinary temperature and have a melting point of about 80 ° C. or more are exemplified. In addition, lubricants such as zinc stearate, calcium stearate, and aluminum stearate, various surfactants, antifoaming agents, and the like are added as needed.

The heat-sensitive recording material of the present invention is prepared by using the above-mentioned materials by, for example, the following method. That is, first by a conventional method, a color milling compound, a color developing compound, a hydrogenated terpene polymer or a hydrogenated terpene-phenol copolymer each separately with a binder or a ball mill attritor together with other additives as necessary, After pulverizing and dispersing with a dispersing machine such as a sand mill (the hydrogenated terpene polymer or the hydrogenated phenol terpene copolymer may be preliminarily mixed with a color-forming compound or a color-developing compound for dispersion. ) Mix to prepare a thermosensitive coloring layer coating solution, paper,
Usually 5 to 4 on a support such as a plastic sheet or synthetic paper.
0 g / m ² by a bar coater, a spread coater or the like (the ratio of the color-forming compound to the color-developing compound is usually 1: 1 to 1:10 in terms of dry weight ratio) and dried. Obtain the recording material.

If necessary, an intermediate layer may be provided between the thermosensitive coloring layer and the support, or an overcoat layer may be provided on the thermosensitive coloring layer. The heat-sensitive recording material of the present invention containing a hydrogenated terpene polymer or a hydrogenated terpene-phenol copolymer has excellent color image storage stability as compared with conventionally known materials.

[0022]

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

Embodiment 1 FIG. The mixture of the following composition was pulverized for 30 minutes using a sand grinder, and each of the liquids (A),
Solutions [B] and [C] were prepared. [A] solution: 2-o-fluoroanilino-6-25 parts dibutylaminofluorane 25% PVA aqueous solution 20 parts water 55 parts [B] solution: bisphenol A 8 parts p-acetotoluidide 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: hydrogenated terpene-phenol copolymer (softening point about 130 ° C, molecular weight about 650) 25 parts 25% PVA Aqueous solution 20 parts Water 55 parts

[0024] Then the [A] solution: [B] was: [C] solution = 6: 74 parts were mixed at a ratio of 20 parts of heat-sensitive color developing layer coating solution was prepared, having a basis weight of 50 g / m ² Liquid volume 3 on high quality paper
It was applied to a concentration of 0 g / m ² and dried to provide a thermosensitive coloring layer. Further, a 10% PVA aqueous solution was applied on the thermosensitive coloring layer and dried so that the coated amount after drying was 3 g / m ² , to obtain a thermosensitive recording material of the present invention.

Embodiment 2 FIG. In Example 1, [D] solution having the following pulverized composition instead of [A] solution [D] solution: 2-anilino-3-methyl-6-cyclohexyl 25 parts Methylaminofluorane 25% PVA aqueous solution 20 parts Water Using 55 parts, [D] solution: [B] solution: [C] solution: water = 6 parts: 74
Parts: 10 parts: 10 parts by weight to prepare a thermosensitive coloring layer coating solution, the amount of which is 30 g on a high-quality paper having a basis weight of 50 g / m ^2.
/ M ² and dried to form a thermosensitive coloring layer. Further, a 10% PVA aqueous solution was applied onto the thermosensitive coloring layer so that the coated amount after drying was 3 g / m ^2, and dried to obtain a thermosensitive recording material of the present invention.

Embodiment 3 FIG. In Example 1, [E] solution having the following pulverized composition instead of [B] solution [E] solution: p-hydroxybenzoic acid benzyl ester 8 parts Calcium carbonate 13.5 parts Carboxylated SB latex (50%) 7 parts 25 % PVA aqueous solution 5 parts Water 66.5 parts Using [A] solution: [E] solution: [C] solution = 6 parts: 74 parts:
A thermosensitive coloring layer coating solution was prepared by mixing at a ratio of 20 parts, and a thermosensitive coloring layer coated and dried on a high quality paper having a basis weight of 50 g / m ^{2 so} as to have a solution amount of 30 g / m ² was provided. Further, the amount of the 10% PVA aqueous solution after drying was 3 g on the thermosensitive coloring layer.
/ M ² and dried to obtain a heat-sensitive recording material of the present invention.

Embodiment 4 FIG. The mixture having the following composition was pulverized for 1 hour by using a sand grinder, and each of the mixture [F]
[G] A solution was prepared. [F] Liquid: 2-o-fluoroanilino-6-diethyl 10 parts Aminofluoran p-acetotoluidide 30 parts 25% PVA aqueous solution 20 parts Water 40 parts [G] Liquid: bisphenol S 8 parts White carbon 6.5 parts 15% aqueous casein solution 9.3 parts Acrylic resin emulsion (40%) 8.3 parts Water 67.9 parts

Next, [F]: [G] solution: [C] solution = 18
Parts: 72 parts: 10 parts by weight to prepare a thermosensitive coloring layer coating solution, the amount of which is 30 g on a high-quality paper having a basis weight of 50 g / m ^2.
/ M ² and dried to obtain a thermosensitive coloring layer.
Further, a 10% PVA aqueous solution was applied onto the thermosensitive coloring layer so that the coated amount after drying was 3 g / m ^2, and dried to obtain a thermosensitive recording material of the present invention.

Embodiment 5 FIG. In Example 4, instead of the liquid [C], the liquid [H] having the following pulverized composition [liquid H]: 25 parts of hydrogenated terpene polymer (softening point: about 140 ° C., molecular weight: about 980) 25% PVA aqueous solution 20 parts: water 55 A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 4, except for using parts.

Embodiment 6 FIG. Instead of the solution [C] in Example 4, the solution [I] of the following pulverized composition [I] solution: 25 parts of hydrogenated terpene-phenol copolymer (softening point: about 100 ° C., molecular weight: about 600) 25% PVA aqueous solution 20 A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 4 except that 55 parts of water was used.

Embodiment 7 FIG. In Example 4, instead of the liquid [C], the liquid [J] having the following pulverized composition [liquid J]: hydrogenated terpene-phenol copolymer (softening point: about 140 ° C., molecular weight: about 1000) 25 parts 25% PVA aqueous solution 20 A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 4 except that 55 parts of water was used.

Comparative Example 1 In Example 1, [C] solution 20
A heat-sensitive recording material for comparison was obtained in the same manner as in Example 1 except that 20 parts of water was used instead of 20 parts.

Comparative Example 2 In Example 2, [C] solution 10
A comparative thermosensitive recording material was obtained in the same manner as in Example 2 except that 10 parts of water was used instead of 10 parts.

Comparative Example 3 In Example 3, [C] solution 20
[K] solution having the following pulverization composition [K] solution: 2,2'-methylene-bis (4-methyl-6-25 parts t-butylphenol 25% aqueous solution of PVA 20 parts Water 55 parts 20 parts A heat-sensitive recording material for comparison was obtained in the same manner as in Example 3 except for the above.

Comparative Example 4 A heat-sensitive recording material for comparison was obtained in the same manner as in Example 4, except that water was used in place of the solution [C] in Example 4.

Comparative Example 5 In Example 4, [C] solution 10
Instead of parts, 10 parts of [L] solution having the following pulverized composition [L] solution: 4,4'-thiobis (3-methyl-6-t-25 parts butylphenol) 25% PVA aqueous solution 20 parts Water 55 parts A heat-sensitive recording material for comparison was obtained in the same manner as in Example 4 except for the above.

Using the heat-sensitive recording material of the present invention obtained as described above and a heat-sensitive recording material for comparison, the following quality performance tests were carried out.

Table 1 Results of Quality Performance Test Image density 1) Water resistance 2) Plasticizer resistance 3) Example 1 1.21 1.01 0.70 Example 2 1.33 1.10 0.81 Example 3 1.38 1.07 1.02 Example 4 1.35 1.06 1.21 Example 5 1.31 1.00 1.24 Example 6 1.30 1.03 1.20 Example 7 1. 35 1.01 1.23 Comparative Example 1 1.20 0.72 0.26 Comparative Example 2 1.32 0.79 0.39 Comparative Example 3 1.40 0.70 0.71 Comparative Example 4 1.32 0 .46 0.69 Comparative Example 5 1.35 1.00 0.98

1) Image density Thermal printer manufactured by Ishida Koki Co., Ltd.
(D-805P) A value obtained by measuring the density at which the sample was printed using a Macbeth reflection densitometer RD-914. 2) Water resistance The value measured by the Macbeth reflection densitometer on the printed portion after the sample printed by the thermal test printer was immersed in tap water at room temperature for 24 hours. 3) Soviability resistance The sample printed with the above thermal test printer was sandwiched from both sides with a PVC wrap film, and the Macbeth reflection density of the printed portion after being left at 40 ° C. under a load of 0.3 kg / cm ² for 15 hours. The value measured by the meter.

As is clear from the table, the heat-sensitive recording material of the present invention is superior in the water resistance and the solvability to the heat-sensitive recording material for comparison.

[0041]

According to the present invention, a heat-sensitive recording material which gives a color image having good water resistance and good resistance to soviability is obtained.

Claims (1)

(57) [Claims] 1. A heat-sensitive recording material characterized in that the coloring layer contains a hydrogenated terpene polymer or a hydrogenated terpene-phenol copolymer.