JPH05162459A - Recording material - Google Patents

Abstract

PURPOSE:To obtain a thermal recording material having high sensitivity and reduced in the fog against heat by providing a thermal color forming layer containing a specific color forming compound, a specific developing compound and methylolstearamlde on a support. CONSTITUTION:2-anilino-3-methyl-6-butylaminofluorane, alkyl or benzyl bis(4- hydroxyphenyl) acetate and 4-methylphenyl mesitylenesulfonate or methylolstfearamide are compounded with an aqueous medium in a predetermined ratio along with a water-soluble polymeric binder and the resulting mixture is ground and dispersed by a dispersing machine such as a ball mill to prepare a coating solution for a thermal color forming layer. This coating solution is applied to a support such as paper or a plastic sheet and dried to form the thermal color forming layer to obtain a thermal recording material. Further, a hot-melt compound such as animal and vegetable waxes or polyethylene wax or higher fatty acid can be added to the thermal color forming layer as a sensitizer.

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 which is excellent in color developability and has little heat and heat and humidity fog.

[0002]

2. Description of the Related Art Generally, a heat-sensitive recording material is prepared by separately dispersing a leuco dye and a color developing agent such as a phenolic substance in the form of fine particles, and then mixing them together, and then adding a binder, a sensitizer and a filler. , A coating liquid prepared by adding an additive such as a lubricant, which is applied to paper, film, synthetic paper, or the like, and one or both of the leuco dye and the developer melt by heating, and a chemical reaction caused by contact causes This is to obtain a color development record. A thermal printer or the like having a built-in thermal head is used for coloring the thermal recording sheet. Compared with other recording methods, this heat-sensitive recording method has (1) no noise during recording,
(2) Phenomena, no need for fixing, (3) Maintenance-free, (4) Machines are relatively inexpensive, etc. It is widely used in the fields of measurement recorders, automatic ticket vending machines, and heat-sensitive recording labels.

Among these fields of use, the use of labels and station automation systems for passenger tickets is increasing with the expansion of POS systems in retail stores and supermarkets. A problem in these applications is that fog is caused by heat and humidity.

Further, in recent years, the demand for high-speed recording has been further increased, and there has been a strong demand for the development of a heat-sensitive recording material capable of sufficiently responding to high-speed recording. The drawback of fog is likely to appear. Conventionally, various methods have been proposed in order to improve heat resistance and heat and humidity resistance, which have good thermal responsiveness, but a satisfactory method has not yet been established.

[0005]

The objects of the present invention are as follows.
It is to solve the drawbacks of the prior art. That is, it is to provide a heat-sensitive recording material having high sensitivity and good storage stability against heat and humidity.

[0006]

The inventors of the present invention have completed the present invention as a result of various studies to achieve the above object. That is, the present invention relates to a thermosensitive recording material comprising a support and a thermosensitive coloring layer mainly composed of a colorless or light-colored coloring compound and a color-developing compound capable of coloring the coloring compound when heated. As the color forming compound,
A compound represented by the following formula (1), a compound represented by the following formula (2) as the color-developing compound, and further mesitylenesulfonic acid-4-methylphenyl ester or methylolstearic acid amide. A heat-sensitive recording material is provided.

[0007]

[Chemical 4]

[0008]

[Chemical 5]

(In the formula (2), R is an alkyl group having 1 to 4 carbon atoms or

[Chemical 6] Represents)

The present invention will be described in detail. In the present invention, the above-described color-forming compound of formula (1), the color-developing compound of formula (2), and mesitylenesulfonic acid-4-methylphenyl ester or methylolstearic acid amide as a main component are used to bond as shown below. The heat-sensitive color forming layer is prepared with an agent and optionally a filler, a heat-fusible compound, a surfactant and the like. The proportion in the thermosensitive coloring layer is 1 to 20 parts by weight, preferably 1 to 5 parts by weight, of the color-developing compound of the formula (2), relative to 1 part by weight of the color-forming compound of the formula (1), and mesitylene. Sulfonic acid-4-methylphenyl ester or methylol stearic acid amide 0.5 to 20 parts by weight, preferably 2 to 10 parts by weight. Further, other color-forming compounds and color-developing compounds can be used in combination in the thermosensitive color-forming layer.

Examples of the color forming compound that can be used in combination include the following. Fluoran compounds, triarylmethane compounds, spiropyran compounds, diphenylmethane compounds, thiazine compounds, lactam compounds,
Examples thereof include fluorene compounds, and specific examples thereof include the following compounds. Fluoran compounds; 2-aniline-3-methyl-6-
Diethylaminofluorane, 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
-Dibutylaminofluorane, 2- (o-fluoroanilino-6-diethylaminofluorane, 2- (o-fluoroanilino) -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-diethylfluorane, 2-chloro-6-diethylaminofluorane, 2-methyl-6-diethylaminofluorane, etc. ,

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-
(1,2-Dimethylaminoindole-3-) isophthalide and other spiropyran compounds; 3-methyl-3-spirodinaphthopyran, 1,3,3-trimethyl-6-nitro-
8'-methoxyspiro (indoline-2,2'-benzopyran) and other diphenylmethane compounds; N-halophenyl-leucoauramine and other thiazine compounds; benzoylleuco methylene blue and other lactam compounds; rhodamine-B-anilinolactam Etc., fluorene compounds; 3,6-bis (dimethylamino)
Fluorene spiro (9,3 ′)-6′-dimethylaminophthalide, [3,6-bis (dimethylamino) fluorene spiro (9,3 ′)-6′-pyrrolidinophthalide],
[3-Dimethylamino-6-diethylaminofluorenspiro (9,3 ')-6'-pyrrolidinophthalide] These color forming compounds may be used alone or in combination.

The following are examples of color-developing compounds that can be used in combination. α-naphthol, β-naphthol, p-octylphenol, 4-t-octylphenol, p-t-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'-
Cyclo-hexylidene 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),
Phenolic compounds such as 2,2-methylenebis (4-chlorophenol), benzyl p-hydroxybenzoate,
Ethyl p-hydroxybenzoate, dibenzyl 4-hydroxyphthalate, dimethyl 4-hydroxyphthalate, 5-
Examples thereof include aromatic carboxylic acid derivatives such as ethyl hydroxyisophthalate, 3,5-di-t-butylsalicylic acid and 3,5-di-α-methylbenzylsalicylic acid, aromatic carboxylic acids or polyvalent metal salts thereof.

In the present invention, a binder is used for providing the heat-sensitive recording layer, and the following binders can be used. Methyl cellulose, methoxy cellulose, hydroxyethyl cellulose, carboxymethyl,
Sodium caboxymethyl cellulose, cellulose, polyvinyl alcohol (PVA), caboxy group-modified polyvinyl alcohol, sulfonic acid group-modified polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch and its derivatives, casein, gelatin water-soluble isoprene rubber, styrene / Alkaline salt of maleic anhydride copolymer Water-soluble substance such as alkali salt of iso (or diiso) butylene / maleic anhydride copolymer or polyvinyl acetate, vinyl chloride / vinyl acetate copolymer, polystyrene, polyacrylic Acid ester, polyurethane, styrene / butadiene (SB) copolymer, carboxylated styrene / butadiene (SB) copolymer, styrene / butadiene / acrylic acid copolymer, colloidal silica and acrylic resin Soluble emulsion such as the composite particles.

Examples of fillers that can be used are calcium carbonate, magnesium carbonate, magnesium oxide, silica,
There are white carbon, talc, clay, alumina, magnesium hydroxide, aluminum hydroxide, aluminum oxide, barium sulfate, polystyrene resin, urea-formalin resin and the like.

Examples of heat-fusible compounds that can be used include waxes such as animal and vegetable waxes, polyethylene waxes, synthetic waxes, and higher fatty acids, higher fatty acid amides, higher fatty acid metal salts, acetylated aromatic amines, and aromatic ethers. Examples thereof include compounds and biphenyl derivatives which are solid at room temperature and have a melting point of about 80 ° C. or higher. In addition, lubricants such as zinc stearate, calcium stearate, and aluminum stearate, various surfactants, antifoaming agents, etc. are added as necessary.

The heat-sensitive recording material of the present invention is prepared by the following method using the above materials. That is, according to a conventional method, first, a color-developing compound, a color-developing compound, mesitylenesulfonic acid-4-methylphenyl ester or methylolstearic acid amide is separately added together with a binder or, if necessary, other additives with a ball mill attritor. After pulverizing and dispersing with a disperser such as a sand mill (mesitylenesulfonic acid-4-methylphenyl ester or methylolstearic acid amide may be mixed with a color-forming compound or a color-developing compound in advance in some cases for dispersion). The thermosensitive color developing layer coating liquid is prepared by mixing and is usually 5 to 40 on a support such as paper, plastic sheet and synthetic paper.
Coating with a bar coater, a blade coater or the like so that g / m ² is obtained (the ratio of the color-forming compound to the color-developing compound is usually 1: 1 to 1:10 by dry weight), and the heat-sensitive material of the present invention. Obtain recording material.

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 color-forming compound of formula (1), the color-developing compound of formula (2), and mesitylenesulfonic acid-4-
The heat-sensitive recording material of the present invention containing methylphenyl ester or methylolstearic acid amide has higher sensitivity, less fog to heat and moist heat, and better storage stability than conventionally known materials.

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, "part" indicates part by weight.

Example 1 A mixture having the following composition was pulverized for 30 minutes using a sand grinder to prepare solutions [A], [B] and [C], respectively. [A] liquid: 2-anilino-3-methyl-6-dibutylaminofluorane 25 parts 25% PVA aqueous solution 20 parts water 55 parts [B] liquid: benzyl bis (4-hydroxyphenyl) acetate 25 parts 25% PVA aqueous solution 20 parts Water 55 parts [C] Liquid: Mesitylenesulfonic acid-4-methylphenyl ester 25 parts 25% PVA aqueous solution 20 parts Water 55 parts

Next, the thermosensitive color developing layer coating liquid was prepared by mixing the following components. [A] liquid 20 parts [B] liquid 60 parts [C] liquid 60 parts 50% calcium carbonate dispersion 50 parts 25% PVA aqueous solution 20 parts water 40 parts

The thermosensitive color-developing layer coating liquid was applied on a high-quality paper having a basis weight of 50 g / m ^{2 so} that the liquid amount was about 30 g / m ^2, and dried to obtain a thermosensitive recording material of the present invention.

Example 2 A thermosensitive recording material of the present invention was prepared in the same manner as in Example 1 except that methyl bis- (4-hydroxyphenyl) acetate was used in place of benzyl bis (4-hydroxyphenyl) acetate of Example 1. Got

Example 3 A thermosensitive recording material of the present invention was prepared in the same manner as in Example 1 except that butyl bis (4-hydroxyphenyl) acetate was used instead of benzyl bis (4-hydroxyphenyl) acetate. Got

Example 4 A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 1 except that methylolstearic acid amide was used in place of the mesitylenesulfonic acid-4-methylphenyl ester of Example 1.

Comparative Example 1 Comparative Example 1 was carried out in the same manner as in Example 1 except that bis- (3-allyl-4-hydroxyphenyl) sulfone was used instead of benzyl bis (4-hydroxyphenyl) acetate of Example 1. A heat-sensitive recording material of was obtained.

Comparative Example 2 In place of 2-anilino-3-methyl-6-dibutylaminofluorane of Example 1, 2-anilino-3-methyl-
A thermal recording material for comparison was obtained in the same manner as in Example 1 except that 6- (N-ethyl-N-isopentylamino) fluorane was used.

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

Table 1 Results of quality performance test Background ¹⁾ Color density ²⁾ Heat resistance ³⁾ Moisture and heat resistance ⁴⁾ Example 1 0.07 1.49 0.12 0.18 Example 2 0.08 1.47 0.11 0.23 Example 3 0.08 1.47 0.13 0.40 Example 4 0.06 1.50 0.11 0.17 Comparative Example 1 0.10 1.43 0.23 1.08 Comparative Example 2 0.09 1.49 0.09 0.93

1) Background: The unprinted portion of the sample was measured by a Macbeth reflection densitometer RD-914 type (reflection density). 2) Color density: reflection density of a sample printed by a thermal printer (D-805P) manufactured by Ishida Kogyo Co., Ltd. 3) Heat resistance: The reflection density of the unprinted part of the sample after standing in a constant temperature and humidity chamber at 70 ° C. for 24 hours. 4) Moisture and heat resistance: Reflection density of the unprinted part of the sample after being left for 24 hours in a thermo-hygrostat at 70 ° C. and 100% relative humidity.

As is apparent from the table, the heat-sensitive recording material of the present invention is excellent in color density, heat resistance and wet heat resistance.

[0032]

EFFECT OF THE INVENTION A heat-sensitive recording material having high sensitivity and good storage stability with less fog against heat and moist heat was obtained.

Claims (1)

[Claims] 1. A thermosensitive recording material comprising a support and a thermosensitive coloring layer comprising a colorless or light-colored coloring compound and a color-developing compound capable of coloring the coloring substance under heat as a main component. The layer contains a compound of the following formula (1) as the color-forming compound and a compound of the following formula (2) as the color-developing compound, and further contains mesitylenesulfonic acid-4-methylphenyl ester or methylolstearic acid amide. A heat-sensitive recording material characterized by containing [Chemical 2] (In the formula (2), R is an alkyl group having 1 to 4 carbon atoms or Represents)