JPH05318936A - Thermal recording material - Google Patents

Abstract

PURPOSE:To prevent deformation or a damage and to enhance color forming properties and preservability by using a compd. represented by a specific chemical formula as the developing compd. of the thermal color forming layer provided on the upper surface of a support and using a copolymer represented by a specific chemical formula as a binder. CONSTITUTION:A thermal recording material is constituted by providing a thermal color forming layer based on a colorless or light-colored color forming compd. a developing compd. allowing the color forming compd. to form a color at the time of heating and a binder on a nylon support or a support processed by nylon. In this case, as the developing compd., a compd. represented by chemical formula (wherein R1-R3 are respectively independently hydrogen, a 5C or less alkyl group or an alkenyl group) is used. As the binder, an acrylic acid/ ethylene copolymer represented by (C2H4CH2CHCOO<->)n.nX<+> (wherein n is a numeral of 1000 or less and X is hydrogen, Na, K, NH4 or the like) is used.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a heat-sensitive recording material.
More specifically, the present invention relates to a heat-sensitive recording material which is not deformed or damaged by folding or bending and has excellent color development and high storage stability.

[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,
Due to the features such as (2) no need for development and fixing, (3) maintenance-free, (4) relatively inexpensive machines, the field of facsimiles, computer output, printers such as calculators, medical It is widely used in the fields of measurement recorders, automatic ticket vending machines, and heat-sensitive recording labels.

Conventionally, hard plastic films typified by paper, synthetic paper and polyester films have been used as a support for such materials. These are selected because it is easy to keep a flat surface and the surface is uniform according to the conventional wisdom of handwriting. However, in the case of recording by contact of the thermal head surface such as a thermal recording system, the recording sheet surface can be formed. As far as possible, it is preferable to follow the surface of the thermal head. For this reason, in addition to the flatness and smoothness of the recording sheet, conditions such as softness and flexibility also have a great effect on the print quality. When ordinary papers are used as a support, when they are bent or folded, they often have creases or scratches due to their hardness and flatness, which impair normal printing or image recording.

A polyamide synthetic polymer, so-called nylon, can be applied as a material which does not have such inconvenience and can serve as a physically and chemically stable support. However, because of the chemical structure of nylon, which has a strongly reducing polyamide bond, the heat-sensitive color development method that uses a leuco dye has a problem that it impairs the color development function and causes defective printing or decolorization of the recording layer. ing.

[0005]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention
It is to solve the drawbacks of the prior art. That is, it is an object of the present invention to provide a heat-sensitive recording material using as a support a nylon and a base material processed with nylon, which is not deformed or damaged by folding or bending and has excellent color developability and high storage stability.

[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 heat-sensitive material containing, as a main component, a colorless or light-colored color-forming compound, a color-developing compound capable of coloring the color-forming substance under heat, and a binder on nylon or a support processed with nylon. A thermosensitive recording material provided with a color-forming layer contains a compound of the following formula (1) as the color-developing compound and a copolymer of acrylic acid and ethylene represented by the following formula (2) as a binder. A heat-sensitive recording material characterized by the above.

[0008]

[Chemical 3]

(In the formula (1), R ₁ , R ₂ and R ₃ each independently represent hydrogen, an alkyl group having 5 or less carbon atoms or an alkenyl group.)

[0010]

(C ₂ H ₄ CH ₂ CHCOO ⁻ ) _n · nX ⁺ (2) (In the formula (2), n is a number of 1,000 or less, and X is hydrogen, Na, K, NH ₄ or an alkanol. Each represents an amine cation.) The present invention will be described in detail.

The nylon or the support processed with nylon used in the present invention includes, as an example of a single form, a nylon film, a nylon woven cloth, a nylon nonwoven cloth and the like. Examples of the nylon-processed material include those in which sheet-shaped nylon is bonded to a general plastic film such as a polyester film or a polyethylene film by a conventional method, nylon particles are coated, or JP-A-57-77372. , JP-A-59
-91050, a base cloth made of nylon and polyester or cotton as disclosed in Japanese Patent Laid-Open No. 62-32632 is immersed in a calcium chloride / methanol solution, or a nylon resin is dissolved in a calcium chloride / methanol solution. It is possible to use a product obtained by a wet coagulation treatment with a product. The types of nylon are 6,
6-nylon, 6,10-nylon, 6-nylon, 7
-Nylon, 11-nylon and other polyamide synthetic polymers are considered, but 6,6-nylon and 6-nylon are common. Next, the thermosensitive coloring layer of the present invention contains a color-forming compound, a color-developing compound of the above formula (1) and a copolymer of acrylic acid and ethylene of the above formula (2) as a binder as main components, In addition, if necessary, the thermosensitive color-developing layer is prepared by using a filler, a heat-fusible compound, a surfactant and the like as described below in combination. The proportion in the thermosensitive color developing layer is appropriately 1 to 10 parts by weight, preferably 1 to 5 parts by weight, of the color-developing compound of the formula (1) per 1 part by weight of the color-forming compound. The copolymer of the formula (2) is contained in the thermosensitive coloring layer,
1 to 80% by weight, preferably 10 to 30% by weight is suitable. Further, other color-developing compounds and binders can be used in combination in the color forming layer.

Examples of the color forming compound include the following. That is, a fluorane compound, a triarylmethane compound, a spiropyran compound, a diphenylmethane compound, a thiazine compound, a lactam compound, a fluorene compound and the like can be mentioned, and specific examples thereof include the following compounds.

Fluoran compounds; 2-anilino-3-
Methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-dibutylaminofluorane, 2-anilino-3-methyl-6- (N-methyl-N-cyclohexylamino) fluorane, 2-anilino-3 -Methyl-6- (N-ethyl-N-isopentylamino) fluorane, 2-anilino-3-methyl-6-isobutylethylaminofluorane, 2-anilino-3-methyl-6-
[N-ethyl-N- (3-ethoxypropyl) amino]
Fluorane, 2-anilino-3-methyl-6- (N-ethyl-N-hexylamino) fluorane, 2-anilino-3-methyl-6-dipentylaminofluorane, 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-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 and the like.

These color forming compounds may be used alone or as a mixture.

Examples of the color-developing compound represented by the formula (1) include 4,4'-sulfonyldiphenol and 4,4 '.
-Sulfonyl-bis- (2-allylphenol), 4-
Hydroxy-4'-methoxydiphenyl sulfone, 4-
Hydroxy-4'-ethoxydiphenyl sulfone, 4-
Examples thereof include hydroxy-4′-isopropoxydiphenyl sulfone and 4-hydroxy-4′-butoxydiphenyl sulfone, which may be used alone or as a mixture.

Further, examples of the color-developing compound other than the formula (1) that can be used in combination include the following.

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, 2,2'-bis (2,2
5-dibromo-4-hydroxyphenyl) propane,
4,4'-isopropylidene bis (2-t-butylphenol), 2,2'-methylenebis (4-chlorophenol), methyl bis (4-hydroxyphenyl) acetate,
Butyl bis (4-hydroxyphenyl) acetate, bis (4
-Hydroxyphenyl) benzyl compounds such as benzyl acetate, benzyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, dibenzyl 4-hydroxyphthalate, dimethyl 4-hydroxydiphthalate, ethyl 5-hydroxyisophthalate, 3,5- Aromatic carboxylic acid derivatives such as di-t-butylsalicylic acid and 3,5-di-α-methylbenzylsalicylic acid, aromatic carboxylic acids or polyvalent metal salts thereof.

The acrylic acid-ethylene copolymer of the formula (2) which is a binder is a compound having a monomer component of acrylic acid and ethylene, a molecular weight of about 100,000 or less, and an acid value of about 150. Is commercially available, for example, under the following trade name (Sumitomo Seika Co., Ltd. product). That is, water-soluble type, Saixen-A (NH4 salt), Saixen-A
C (NH4 salt), Saixen-L (alkanolamine salt), Saixen-N (Na salt) and the like, and resin types such as Saixen-F and Saixen-FP.

The following are examples of binders that can be used in combination with the binder of formula (2).

Methyl cellulose, methoxy cellulose,
Hydroxyethyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, cellulose, polyvinyl alcohol (PVA), carboxyl group-modified polyvinyl alcohol, sulfonic acid group-modified polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch and its derivatives, casein, water-soluble gelatin. Isoprene rubber, styrene / maleic anhydride copolymer alkali salt iso (or diiso)
Water-soluble substances such as alkali salts of butylene / maleic anhydride copolymer or polyvinyl acetate / vinyl acetate copolymer, polystyrene, polyacrylic acid ester, polyurethane, styrene / butadiene (SB) copolymer, carboxylated styrene / Butadiene (SB) copolymer, styrene / butadiene / acrylic acid copolymer, water-soluble emulsion such as composite particles of colloidal silica and acrylic resin.

Examples of the filler usable in the heat-sensitive recording material of the present invention include calcium carbonate, magnesium carbonate, magnesium oxide, silica, white carbon, talc, clay, alumina, magnesium hydroxide, aluminum hydroxide, aluminum oxide, There are barium sulfate, polystyrene resin, urea-formalin resin and the like.

Further, in the heat-sensitive recording material of the present invention, usable heat-fusible compounds are animal and vegetable waxes,
Waxes such as polyethylene wax and synthetic wax, higher fatty acids, higher fatty acid amides, higher fatty acid metal salts,
Acetylated products of aromatic amines, aromatic ether compounds,
Examples thereof include those that are solid at room temperature and have a melting point of about 80 ° C. or higher, such as biphenyl derivatives.

In addition, lubricants such as zinc stearate, calcium stearate and aluminum stearate, various surfactants, antifoaming agents and the like are added as required.

The heat-sensitive recording material of the present invention is prepared by using the above-mentioned material by the following method, for example.

That is, according to a conventional method, first, a color-forming compound and a color-developing compound of the above formula (1) are separately separately added together with a binder or, if necessary, other additives, in a ball mill,
After pulverizing and dispersing with a disperser such as an attritor or a sand mill, the copolymer of the above formula (2) has a dry solid content ratio of 1
A thermosensitive color developing layer coating solution is prepared by adding 0 to 30% by weight. Then, the prepared solution is applied onto a nylon or a support processed with nylon by a bar coater, a blade coater or the like so that the dry weight is usually 1 to 20 g / m ² (the ratio of the color forming compound to the color developing compound is Usually, the dry weight ratio is 1: 1 to 1:10), followed by drying to obtain the heat-sensitive recording material of the present invention.

If desired, 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 color-developing compound of the above formula (1) and the copolymer of the above formula (2) is
Compared with the conventionally known ones, they are softer, have better matching with the thermal head surface, have excellent color development and have high storage stability.
It is also characterized by being less likely to be deformed by being bent or bent and not being scratched.

[0028]

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

Example 1 A mixture having the following composition was ground for 30 minutes using a sand grinder to prepare a liquid [A] and a liquid [B], respectively.

[A] liquid: 2-anilino-3-methyl-6-dibutylaminofluorane 40 parts 25% PVA aqueous solution 20 parts water 40 parts [B] liquid: 4,4′-sulfonyl-bis- (2- Allylphenol) 20 parts p-Benzylbiphenyl 20 parts 25% PVA aqueous solution 20 parts Water 40 parts Then, a thermosensitive color developing layer coating liquid was prepared by mixing in the following proportions.

[A] liquid 5 parts [B] liquid 50 parts Zyksen-AC (30% acrylic acid / ethylene copolymer NH ₄ salt aqueous solution, Sumitomo Seika Chemicals Ltd.) 20 parts 70% calcium carbonate aqueous dispersion 10 parts water 15 parts The thermosensitive coloring layer coating solution was applied onto a nylon woven fabric (70 denier basis weight, 70 g / m ² taffeta) using a wire bar so that the dry weight was about 12 g / m ^2. After coating and drying, a heat-sensitive recording material of the present invention was obtained.

Example 2 The procedure of Example 1 was repeated except that 4,4′-sulfonyl-bis- (2-allylphenol) in Example 1 was replaced with 4,4′-sulfonyldiphenol. A heat-sensitive recording material of the invention was obtained.

Example 3 As Example 1 except that 4-hydroxy-4′-isopropoxydiphenyl sulfone) was used in place of 4,4′-sulfonyl-bis- (2-allylphenol) of Example 1. Similarly, a heat-sensitive recording material of the present invention was obtained.

Example 4 20 parts of 6-nylon, 58 parts of methanol were placed on a 75 denier polyester woven fabric instead of the nylon woven fabric of Example 1.
Parts, 24 parts of calcium chloride, 7 parts of calcium carbonate were applied so as to be about 70 g / m ² , and then a white sheet obtained by dipping in water, coagulation, extraction, washing with water, and drying was used. A thermal recording material of the present invention was obtained in the same manner as in Example 1.

Example 5 Instead of Saixen-AC of Example 5, Saixen-L
A thermal recording material of the present invention was obtained in the same manner as in Example 5 except that (25% alkanolamine salt, manufactured by Sumitomo Seika Chemicals, Ltd.) was used.

Example 6 Instead of Saixen-AC of Example 5, Saixen-N
(25% Na salt, manufactured by Sumitomo Seika Co., Ltd.)
A thermal recording material of the present invention was obtained in the same manner as in Example 5.

Comparative Example 1 A thermosensitive recording material for comparison was obtained in the same manner as in Example 1 except that carboxylated styrene / butadiene copolymer latex was used instead of Saixene-AC in Example 1.

Comparative Example 2 4,4'-sulfonyl-bis-in the liquid [A] of Example 1
Bisphenol A instead of (2-allylphenol)
Also, instead of Saixen-AC, PVA (saponification degree =
86.5 to 89.0 mol%, degree of polymerization = 1,000 or less)
A thermal recording material for comparison was obtained in the same manner as in Example 1 except that was used.

Comparative Example 3 Instead of the nylon woven fabric used in Example 1, the basis weight = about 5
A thermosensitive recording material for comparison was obtained in the same manner as in Example 1 except that 0 g / m 2 of high quality paper was used as the support.

Comparative Example 4 Instead of the nylon woven fabric used in Example 1, thickness = 10.
A thermosensitive recording material for comparison was obtained in the same manner as in Example 1 except that a transparent polyester film of 0 μm was used as the support.

The following quality tests were carried out on the heat-sensitive recording materials of the present invention and comparative examples obtained as described above.

[0042]

[Table 1] In Table 1, each test item was carried out as follows.

1) Color density: A value measured by a Macbeth reflection densitometer RD-914 type on a sample printed by a thermal printer (D-805P) manufactured by Ishida Koki Co., Ltd.

2) Moisture and heat resistance: The residual rate (%) of the image portion after the sample colored by the printer was left in a thermo-hygrostat at 40 ° C. and 90% relative humidity for 24 hours.

3) Flex resistance: According to the flex test of JIS K 5400. The restored state of the sample when a mandrel having a diameter of 2 mm under the strongest condition of a bending resistance tester (manufactured by Tester Sangyo Co., Ltd.) was used and the printing quality when printing was performed by the above printer were determined.

○ The appearance and print quality are the same as before the test.

Δ Folding occurred, but there was no problem in print quality.

× Folding occurs and print quality is poor.

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

[0050]

[Effects of the Invention] It is hard to be deformed by folding or bending and is not scratched. Therefore, a heat-sensitive recording material using a nylon or a nylon-processed product as a support, which has a good matching with the thermal head surface, excellent color development, and good storage stability, was obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yosuke Tsugawa 563 Oyama, Matsudo City, Chiba Prefecture (72) Inventor Yuriko Mukai 35-15 Iwabuchicho, Kita-ku, Tokyo 202 Asahi Corp 202

Claims (1)

[Claims] 1. A heat-sensitive color-developing layer containing, as a main component, a colorless or light-colored color-forming compound, a color-developing compound capable of coloring the color-forming substance under heat, and a binder on nylon or a support processed with nylon. In the heat-sensitive recording material, the compound of formula (1) below is contained as the color-developing compound, and the copolymer of acrylic acid and ethylene represented by formula (2) below is contained as a binder. Characteristic thermal recording material. [Chemical 1] (In the formula (1), R ₁ , R ₂ and R ₃ each independently represent hydrogen, an alkyl group having 5 or less carbon atoms or an alkenyl group.) (C ₂ H ₄ CH ₂ CHCOO ⁻ ) _N · nX ⁺ (2) (In the formula (2), n represents a number of 1,000 or less, and X represents hydrogen, Na, K, NH ₄ or an alkanolamine cation.)