JPS58132593A - Thermosensitive recording sheet - Google Patents

Abstract

PURPOSE:To provide a thermosensitive recording sheet which is ideal for tickets, heat sensitive papers of medical examination equipment or the like with an excellent water resistance of a colored images by providing a heat sensitive coloring layer containing a specific phenol-like material with coloring colorless dye. CONSTITUTION:A thermosensitive coloring layer containing one or more kinds of colorless or light color coloring colorless dye[e.g. 3-(N-cyclohexyl-N-methylamino)-6-methyl-7-anilinofluoran]and a phenol-like material[e.g. bis(4-hydoxyphenyl) sulfonemonobenzyleter]of formula[R represents C1-10 alkyl, benzyl (possibly with a substitution group)]on a supporting body to obtain an intended thermal recording sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-sensitive printing sheet, and more particularly to a heat-sensitive recording sheet with excellent water resistance of colored images.

In general, heat-sensitive N self-recording sheets are made by forming a heat-sensitive PI layer containing a color-forming colorless dye and a coloring agent such as phenolic 11121 as the main components on a support rod such as paper or film. Color recording is obtained through an instantaneous chemical reaction caused by heating of the head, etc.

Compared to other recording materials, this heat-sensitive recording sheet does not require complicated processing such as phenomenon and fixing, and records can be written in a relatively short time, and there is no noise, and it is unique. Due to its low cost and other advantages, it is widely used not only for copying documents such as diagrams, but also as a recording material for electronic computers, facsimile machines, telex medical measuring instruments, and other devices.

However, if a heat-sensitive recording sheet that is a combination of such a color-forming colorless dye and a phenolic substance* is exposed to water or immersed in water, the image will be 9J! Some parts have faded. It loses its value as a record. This phenomenon occurs as a result of the gradual release of phenolic substances into the water.
% colorless (this is thought to be due to the colorless dye returning to its original colorless state).

If you use a phenolic substance that has a strong binding force with color-forming colorless dyes and has a low solubility in water, it is effective because the image area will not get wet even if it is splashed with water or immersed in water. can be expected. Improved water resistance 7? Examples of uses that require a heat-sensitive self-edge sheet include heat-sensitive paper labels for use in cars and office staff, barcode barcodes for POS at mass retailers, etc.

This durable thermal paper has the ability to be splashed with water or immersed in water, making it a popular thermal paper.

There was a drawback that the image became discolored.

In addition, as an improvement on conventional thermal paper, a paper has been proposed in which a water-soluble cylindrical overcoat layer is provided on the thermosensitive coloring layer, but this paper has thermal sensitivity because the overcoat layer impedes heat conduction. However, it has the drawback of being costly because it requires a step of applying an overcoat layer.

Therefore, in order to provide a heat-sensitive recording sheet with good water resistance without worrying about just one overcoat, it is necessary to use a phenolic substance that has a strong binding force with color-forming colorless dyes and has low bath decomposition with water. It is necessary to take action.

As a result of repeated research on the meaning of carp for the above purpose, the present inventors found that
Usually colorless! The second step is to find a heat-sensitive recording sheet containing at least one light color-forming colorless dye and a phenolic substance represented by the following general formula (i), which is the most suitable ink for this purpose. The light of the present invention has been achieved.

[In the formula, RFi represents an alkyl group having 1 to 10 carbon atoms or a benzyl group (having an m substituent). ]Next, as the normally colorless to light-colored colorless dye used in the present invention, there are well-known dyes such as 1-bo dyes, and although there are no particular limitations, examples include crystal violet lactone 3-(N- Ethyl-p,-toluidino)-6-methyl-
7-anilinofluorane 3-diethylamino-6-methyl-7-(orthopara-
dimethylanilino)fluoran 3-pyrrolidino-6-methyl-7-anilinofluoran 3-piperidino-6-methyl-7-anilinofluoran 3-(N-7chlorohexyl-N-methylamino)-6-
Methyl-7-anilinofluorane 3-diethylamino-
7-(orthochloroanilino)fluoran 3-diethylsminor 7-(methatrifluoromenalanilino)fluoran 3-diethylamino-6-methyl-7-chlorofluoran 3-diethylamino-6-methyl-fluoran 3-cyclohexyl Fill with amino-6-chlorofluorane or the like.

5- In addition, 7 of the general formula (I) used in the present invention,
In the heat-sensitive coloring layer of the present invention, it is possible to appropriately use conventional binders for bonding and supporting on the support, such as polyvinyl alcohol, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, Water-soluble materials such as polyacrylamide, polyacrylic acid, starch, gelatin, etc., or more aqueous emulsions such as polystyrene, vinyl chloride-vinyl acetate copolymer, borizotyl methacrylate, etc. can be used as binders. can.

In addition, if necessary, conventional auxiliary additives, such as fine powders of FA, calcium acid, silica, alumina, magnesia, Merck, titania, barium sulfate, aluminum sudeate, etc., may be added to the heat-sensitive coloring solution. , the clarity of the colored image can be improved by 6- Same as above.

The heat-sensitive recording sheet of the present invention is produced by applying a coating liquid for forming a heat-sensitive layer containing the above-mentioned components onto a suitable support such as paper, synthetic paper, or plastic film, and drying it. It has excellent water resistance and is used as a heat-sensitive recording sheet.

Next, the present invention will be further explained based on an example.

implementation? According to the composition of 11'F, the following liquids were separately pulverized and dispersed for 2 days using a magnetic ball mill to obtain [A) liquid and [B''l
B, [C″l 豫 was simulated.

[A) 3-(N-cyclohexyl-N-methylamino)-6-
Methyl-7-anilite fluorane 2L)I
IL transportation! 10% hydroxyethylcellulose water bath W
20 #Water
60 〃[B″I bis(4-hydroxyphenylnosul7one monopenzyl ether (m, p-167-168°U) 2
OJkffi part (in general formula (1), R is benzyl) 10% hydroxyethyl heptylulose water bath solution
2oxts water
60 [C] Liquid calcium carbonate 20 wa 1 part 5-thimethylcellulose water bath Q 20# water
A heat-sensitive coloring layer solution having the following composition was prepared using (A) to [C) & obtained by heating at 60 N or more, and dried and spread on a commercially available high-quality paper with a standard basis weight of 50 g/day. A wire bar is selected to apply the coating and dry, and then calendering is performed so that the smoothness of the heat-sensitive coloring layer becomes 500 to 600 seconds in Bekk smoothness. made.

Thermosensitive coloring layer liquid [A) liquid 10 covered part CB) liquid 30#
C″3 liquid 30 20% alkaline water bath of inzotylene-pyrohydric maleic acid copolymerization group 10 Comparative example 1 All procedures were carried out in the same manner as in the example except that the following liquid [D] was used instead of the CB) liquid in the example. A thermosensitive recording sheet (b) was prepared.

[D) & Bisphenol A 20 target part 10% hydroxyethyl cellulose water m liquid
20 #Water 6
0 #Ratio [1 Tari 2 Thermal recording sheet (C) was prepared in the same manner as in the example except that the following liquid (E) was used instead of the CB) liquid in the example.
made.

(E) Liquid p-hydroxybenzoic acid penzylephthyl 2
0fitfftS10% hydroxyethyl cellulose water fiHOL 20# water
601 The heat-sensitive recording sheets (a) to (,) obtained as above were printed at 150° C. with a pressure of 2 KF and a contact time of 1 second using an S1 inclination tester (manufactured by Yokanki). For the heat-sensitive recording sheets of (a) to (a), cut out 4 square pieces with the printed area in the center, and soak each piece separately with tap water.
It was immersed in a beaker of c sea fc100TILl for 24 hours, taken out, dried, and the IIk degree of the Iil image area was determined using Macbeth RD514, and compared with #friend before the test.Table-1
Table 1 As is clear from Table 1, the heat-sensitive recording sheet of the present invention has water resistance iC4&re-fCIl! It can be seen that this is a stable heat-sensitive recording sheet of Monk II.

10-

Claims (1)

[Scope of Claims] 1. Providing a heat-sensitive epichromatic layer fir on the supporting body containing at least one Vr-usually colorless or light-colored colorless dye and a phenolic substance represented by the following general formula (1). A heat-sensitive recording sheet characterized by: [In the formula, R represents an alkyl group having 1 to 10 carbon atoms or a benzyl group (having an ijlf substituent). ]