JPH01130973A - Thermosensitive recording material - Google Patents

Abstract

PURPOSE:To obtain a high plasticizer-resistant thermosensitive recording material by adding isobutylene-N-phenylmaleimide-anhydrous maleic acid copolymer and water-soluble epoxy compound to a thermosensitive color developing layer. CONSTITUTION:Isobutylene-N-phenylmaleimide-anhydrous maleic acid is obtained by copolymerizing isobutylene: N-phenylmaleimide: anhydrous maleic acid at a weight ratio of 50:45-20:5-30. The preferable use amount of isobutylene-N- phenylmaleimide-anhydrous maleic acid is 5-50weight%, of the total weight of thermosensitive recording color developing layer. Polyamide epoxy resin, lauryl alcohol glycidyl ether, etc., are used as water-soluble epoxy compounds. The preferable consumption of the water-soluble epoxy compound is 5-100wt.% of the total weight of the copolymer. A color developing compound and a developing compound are crushed and dispersed separately with water or an additive using a dispersing device. Further, an alkali salt solution of isobutylene-N- phenylmaleimide-anhydrous maleic acid copolymer is prepared separately. Then this solution and the water-soluble epoxy compound are mixed to prepare an application solution. Next, this preparation is applied on a support and dried.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material with excellent preservability of colored images.

Prior 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 Japanese Patent Publication No. 43.
It was published in No.-41/+O and Japanese Patent Publication No. 14039/1983 and has been widely put into practical use. Generally, heat-sensitive recording materials are made by separately dispersing a leuco dye and a color developer such as a phenolic substance into fine particles, then mixing the two and adding additives such as a binder, sensitizer, filler, and lubricant. 1 as a coating liquid by adding
paper.

It is coated on a support such as a film or synthetic paper, and when heated, a leuco dye and/or a color developer melt and come into contact, resulting in a chemical reaction that occurs to obtain a colored record.It is usually a sheet-shaped heat-sensitive record. Materials are prepared. A thermal printer or the like having a built-in thermal head is used to color the heat-sensitive recording sheet. Compared to other recording methods, this thermal recording method has (1) no noise during recording; (
2) No need for developing and fixing, etc. (3) Maintenance free.

(4) Because the machine is relatively inexpensive, it is widely used in facsimile fields, computer output, printers such as calculators, medical measurement recorders, automatic ticket vending machines, thermal recording labels, etc. It is being

Among these fields of use, the use of labels for retail stores, supermarkets, etc. with the expansion of POS systems, train tickets for station automation systems, etc. is increasing. A problem in these applications is that the colored image disappears or fades due to contact with plastic sheets or water leakage. Among the above, the phenomenon of decoloring and/or fading of colored images due to contact with plastic sheets is caused by the fading agent contained in plastics, but the thermal recording method K is expanding from short-term applications such as commuter passes and various cards to long-term applications such as commuter passes and various cards, and conventional methods of increasing plastic resistance (anti-polymers) are becoming increasingly inadequate. It's here.

Problems to be Solved by the Invention It is an object of the present invention to solve the drawbacks of the prior art. That is, plastic sea) i%,! ：An object of the present invention is to provide a heat-sensitive recording material having so-called high wash resistance, which does not cause decoloring or fading of colored images due to long-term contact.

Means for Solving the Problems The inventors of the present invention have completed the present invention as a result of various studies to achieve the above object.

A heat-sensitive recording material having a color layer formed on a support, characterized in that the heat-sensitive coloring layer contains an inbutylene-N-phenylmaleimide-maleic anhydride copolymer and a water-soluble epoxy compound. I will provide a.

Imbutylene-N- used in the heat-sensitive recording material of the present invention
For example, isobutylene, N-phenylmaleimide and maleic anhydride are copolymerized in a weight ratio of inbutin:N-phenylmaleimide:maleic anhydride:50:45 to 20:5 to 30. Copolymers having a molecular weight of 20,000 to 80,000 are usually used for manufacturing. Such copolymers can be used in the heat-sensitive material of the present invention.

In the present invention, a water-soluble epoxy compound is used, but a water-insoluble epoxy compound is not good because it causes fogging and the formation of numerous dots on the background of the heat-sensitive recording coloring layer.

Examples of water-soluble epoxy compounds include polyamide epoxy resin, ethylene polyethylene glycol diglycidyl ether, propylene polypropylene glycol diglycidyl ether, glycerol polyglycidyl ether,
Examples include phoricrycerol polyglycidyl ether, phenol glycidyl ether, and lauryl alcohol glycidyl ether. These water-soluble epoxy compounds act as crosslinking agents for the copolymer (it is thought that the crosslinked copolymer acts as a binder).

The preferred amount of the inbutylene-N-phenylmaleimide-maleic anhydride copolymer used in the present invention is 5 to 50% by weight, more preferably 5 to 20% by weight of the heat-sensitive recording coloring layer.
Weight%. The amount of the water-soluble epoxy compound used is preferably 5 to 100% by weight, more preferably 20 to 50% by weight, based on the weight of the copolymer.

In the heat-sensitive coloring layer of the heat-sensitive recording material of the present invention, inbutylene-
In addition to the N.phenylmaleimide-maleic anhydride copolymer and the water-soluble epoxy compound, a water-soluble polymer acting as a binder as shown below can also be contained.

In this case, the proportion of the copolymer used is at least 20% by weight or more, preferably 50% by weight or more, based on the total amount of the copolymer and water-soluble polymer used.

In the present invention, examples of water-soluble polymers (binder) that can be used in combination with the copolymer include polyvinyl alcohol, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, starch and its derivatives, casein, alginate, polyvinylpyrrolidone, Examples include polyacrylamide.

The heat-sensitive recording material of the present invention contains an inbutylene-N-phenylmaleimide-maleic anhydride copolymer and a water-soluble epoxy resin as shown below (A) a color-forming compound, (B) a color-developing compound, and others as necessary. It is obtained by incorporating it into a heat-sensitive recording coloring layer together with a binder, a filler, a thermofusible compound, a surfactant, and the like.

(A) Rhodamine-β-anilinolactam, rhodamine (p-nitroanilino)lactam, 2-dibenzylamino-6-diethylaminofluorane, 2-anilino-3-methyl-6-diethylamino as a xanthine-based chromogenic compound Fluoran, 2-anilino-3-methyl-6-cyclohexylmethylaminofluorane, 2-anilino-3-methyl-6-impentylethylaminofluorane, 2-anilino-3-methyl-6-sibutylamino fluorane,
2-p-chloroanilino-3/-3-methyl-6-diethylaminofluorane, 2-p-fluoroanilino-3
-Methyl-6-diethylaminofluorane, 2-p-fluoroanilino-3-methyl-6-sibutylaminofluorane, 2-anilino-3-methyl-6-(1)-)luidinoethyl)aminofluorane, 2-1-) Luizino 3-methyl-6-dinithylaminofluorane, 2-0
-chloroanilino-6-diethylaminofluorane%2
-o-chloroanilino-6-sibutylaminofluorane.

2-0-fluoroanilino-6-diethylaminofluorane, 2-0-fluoroanilino-6-sibutylaminofluorane, 2-m-chloroanilino-6-diethylaminofluorane, 2-anilino-3-methyl- 6-piperidinofluorane, 2-anilino-3-methyl-6-pyrrolidinofluorane, 2-m-trifluoromethylanilino-6-diethylaminofluorane, 2-dihexylamino-6-aminofluorane, 2-butylamino-3
-Chloro-6-diethylaminofluorane.

2-Ethoxyethylamino-3-chloro-6-diethylaminofluorane, 2-anilino-5-chloro-6-diethylaminofluorane, 2-diphenylamino-6-
Diethylaminofluorane, 2-anilino-3-methyl-6-siphenylaminofluorane, 2-phenyl-6
-diethylaminofluorane, 2-chloro-3-methyl-6-diethylaminofluorane, 2-chloro-6-diethylaminofluorane, 2-methyl-6-diethylaminofluorane, 6-diethylamino-1,2-penzfluoran etc., 3 as a triarylmethane compound
, 3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone), 3.5-bis(p-dimethylaminophenyl)phthalide, 3-(p-dimethylaminophenyl)- 3
-(1,2-dimethylaminoindol-3-yl)phthalide.

3-Methyl-3-spiro- as spiropyran compounds such as 5-(p-dimethylaminophenyl)-3-(2-methylindol-3-yl)phthalide, chromenes, etc.
dinaphthopyran, 3-benzylspiro-dinaphthopyran, 3-methyl-naphtho-(5-methoxy-benzo)spiropyran, 3-propyl-spiro-dipenzopyran,
1,3. ! l-trimethyl-6'-nitro-8'-methoxyspiro (indoline-2,2'-benzopyran)
, 1,3.3-) dimethyl-6'-nitrospiro (indoline-2,2'-benzopyran), 4,4'- and su-dimethylaminobenzhydrin pendyl ether as diphenylmethane compounds, N-halophenyl -Leuco auramine%N-2p4,5-)lichlorophenyl leuco auramine, benzoyl leucomethylene blue 1p-nitrobenzyl leucomethylene blue as a thiazine compound, and other bis-
5,3-(bis-1,1-(p-dimethylaminophenyl)methylene-2]phthalide, bis-3゜3-[bis-
1,1-('p-dimethylaminophenyl)methylene-
2] 4+5y6+7-titrachlorophthalide, bis-3
,3-Cbis-1,1-(p-diethylaminophenyl)methylene-2)-4,5,6,7-titrachlorophthalide,bis-3,3-(bis-1,1-(p- dimethylaminophenyl)methylene-2) -4 (or 7)-
Divinyl group-containing phthalide derivatives such as ditrophthalide,
5,6-bis(dimethylamino)fluorene spiro(9
,3') -6'-dimethylaminophthalide, 5,6
-bis(diethylamino)fluorenespiro(9,3'
) Fluorene compounds such as -6'-diethylaminophthalide may also be used.

These color-forming compounds may be used alone or in combination.

(B) Color developing compound 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)propane -hydroxyphenyl)cyclohexane, 4.4'-thiobisphenol, 4.4'-cyclo-hexylitine diphenol, 4.4'-sulfonyldiphenol, 4.4'-sulfonyl-bis(
2-allylphenol), 2,2'-bis(2,5-dibromo-4-hydroxyphenyl)propane% 4,4
'-isopropylidene bis(2-t-butylphenol)S2,2'-methylenebis(4-chlorophenol)
Phenolic compounds such as benzyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, dibenzyl 4-hydroxyphthalate, dimethyl 4-hydroxyphthalate, ethyl 5-hydroxyinphthalate, 3.5-di-t
-butylsalicylic acid, aromatic carboxylic acid derivatives such as 3,5-di-α-methylbenzylsalicylic acid, aromatic carboxylic acids or polyvalent metal salts thereof, and the like.

The heat-sensitive recording material of the present invention is prepared using the materials described above, for example, by the following method. That is, first, the color-forming compound and the color-developing compound are separately mixed with water or other additives as necessary, a purulent colloid substance such as polyvinyl alcohol, a surfactant, etc. in a ball mill, attritor, sand mill, etc. using a conventional method. The mixture was pulverized and dispersed using a disperser.

Separately, an alkali compound such as caustic alkali or aqueous ammonia is added to water and an alkali compound such as aqueous ammonia is added to an inbutylene-N-phenylmaleimide-maleic anhydride copolymer and dissolved by heating to obtain an aqueous solution of the alkali salt of the copolymer.

Next, a color-forming compound, a pulverized dispersion of a color-developing compound, an aqueous alkali salt solution of a copolymer of butylene-N-phenylmaleimide-maleic anhydride, and a water-soluble epoxy compound were mixed to prepare a heat-sensitive coloring coating solution. It is coated onto a support such as a sheet or synthetic paper using a bar coater or the like in a ratio of 5 to 402/- (the ratio of color-forming compound to color-developing compound is usually 1:1 to 1:10 in terms of dry weight). )
The heat-sensitive recording material of the present invention is obtained by drying.

If necessary, an overcoat layer of PVA or the like may be provided between the heat-sensitive coloring layer and the support (intermediate layer) or on the heat-sensitive coloring layer.

The heat-sensitive recording material of the present invention, which contains a water-soluble epoxy compound and an inbutylene-N-phenylmaleimide-maleic anhydride copolymer, has a colored image that has much better anti-sodium resistance than conventionally known materials. .

EXAMPLES The present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. In the examples, "1 part" indicates parts by weight.

Example 1 A mixture of the following composition was prepared using a sand grinder (A)
Solution and [B] solution were prepared.

Separately, a mixture of the following composition was stirred and dissolved at 90°C for about 2 hours [C
] A solution was prepared.

= 14- Next, the above [A] solution: [B] solution: [C] solution = 58 parts = 2
7.5 parts and 816 parts of polyethylene glycol diglycidyl ether (molecular weight approximately 420) were mixed together.
．． Add 2 parts to prepare a heat-sensitive coloring layer coating solution, and one tsubo weight is 50f/
M' is coated on high-quality paper so that the liquid amount is 30 f/y/ and dried, and then a 10% PVA aqueous solution is applied on the layer so that the coated amount after drying is 22/d, and then dried. A heat-sensitive recording material of the present invention was obtained.

Example 2 A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 1 except that 30 parts of liquid [C] was used in Example 1.

Example 3 A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 1 except that 0.6 part of polyethylene glycol diglycidyl ether was used.

Example 4 A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 1 except that liquid [D] having the following grinding composition was used instead of liquid [A] in Example 1.

Example 5 A mixture of the following composition was CEel using a sand grinder.
Solution, CF) solution was prepared.

Using [E] solution: [F] solution: [C] solution = 6 parts = 74 parts:
A heat-sensitive coloring layer coating solution was prepared by mixing 16 parts of polyethylene glycol diglycidyl ether (molecular weight: about 420) and 1.2 parts of polyethylene glycol diglycidyl ether (molecular weight: about 420). The coating amount was 301i'/- on high-quality paper, and the layer was dried, and then a 10% PVA aqueous solution was applied on top of the layer, and the coating amount after drying was 3t/rr? The heat-sensitive recording material of the present invention was obtained by coating and drying so as to give the following properties.

Example 6 A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 5 except that phenol glycidyl ether was used instead of polyethylene glycol diglycidyl ether.

Example 7 A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 5, except that a 15% K: polyamide epoxy resin aqueous solution was used instead of polyethylene glycol diglycidyl ether.

Example 8 In Example 5, a mixture of the following composition was used instead of the CCI liquid at 90%
A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 5, except that the solution (()) which had been stirred and dissolved at °C for about 2 hours was used.

Comparative Example 1 A comparative heat-sensitive recording material was obtained in the same manner as in Example 1 except that polyethylene glycol diglycidyl ether was not used.

Comparative Example 2 In Example 1, carboxylated S was used instead of liquid (C).
A comparative heat-sensitive recording material was obtained in the same manner as in Example 1 except that 4.8 parts of B latex (solid content 50%) was used.

Table/Quality performance test results 1) Background Samples with no markings were measured using Macbeth reflection densitometer RD.
-Value measured with type 914.

2) Image Density The density of a sample printed with a thermal test printer (D-8o5p) manufactured by Ishida Koki Co., Ltd. was measured using a Macbeth reflection densitometer RD-914.

3) Agent resistance (I) The sample printed with the previous thermal test printer was sandwiched from both sides with PvC wrap film and left at 40°C for 15 hours under a 7 cm load. Value measured with a densitometer.

4) The value measured using the Macbeth reflection densitometer on the printed area after the test sample of H(ll) (1) was left unloaded at room temperature for 3 months.

As is clear from the table, the heat-sensitive recording material of the present invention containing a water-soluble epoxy compound and an inbutylene-N-phenylmaleimide-maleic anhydride copolymer has a colored image that is more resistant to solubilizing agents than conventionally known materials. is far superior. It also has the characteristic of showing sufficient whiteness even on the background.

Effect of the invention A heat-sensitive recording material was obtained which had significantly superior resistance to detergents.

Patent applicant: Nippon Kayaku Co., Ltd. 121 completed-

Claims (1)

[Claims] 1. In a heat-sensitive recording material in which a heat-sensitive color-forming layer is formed on a support, the main components are a color-forming substance and a color-developing substance capable of causing the color-forming substance to develop color when heated. A heat-sensitive recording material containing a maleimide-maleic anhydride copolymer and a water-soluble epoxy compound.