JPS58134792A - Heat-sensitive recording material - Google Patents

Abstract

PURPOSE:To provide the titled material capable of recording a clear colored image, by incorporating a specified diketone compound into a heat-sensitive color-forming layer comprising a colorless or light-colored leuco dye and an organic acid and/or a phenolic substance for developing the color of the dye when being heated. CONSTITUTION:The objective material is obtained by incorporating (C) a compound of the formula (wherein X is 0-10C (substituted) alkyl, phenyl, ethylene; each of R1, R2 is alkyl, phenyl, alkylated phenyl), e.g., benzil, into a heat-sensitive color-forming layer comprising a combination of a colorless or light-colored basic dye (leuco dye) as a heat-sensitive color forming component and an organic acid (e.g., stearic acid) and/or a phenolic substance (e.g., 4-tert-butylphenol) for developing the color of the dye when being heated. EFFECT:A clear colored image with a high density can be recorded with low thermal energy, and the traveling property of a thermal head is not damaged by adhesion of scum, sticking or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved heat-sensitive recording material that uses a colorless or light-colored leuco dye and an organic acid and/or phenolic plate material that causes the leuco dye to develop color when heated.

Conventionally, a thermosensitive coloring layer that can record image scratches by developing color when heated is provided on a support such as paper, synthetic paper, or resin film.
Various thermal recording materials are known. Compared to other recording materials, it does not require complicated processes such as printing and fixing, can be recorded in a relatively short time, does not generate noise, and is low in cost. It is widely used as a recording material for output printers, facsimile machines, telex machines, various information devices, medical devices, various measuring devices, automatic ticket vending machines, etc. However, these conventional recording materials have several drawbacks17 and have not been satisfactory.

In particular, there is a strong demand for higher speed output machines, and there are no machines that have sufficient thermal sensitivity to meet this demand. For this reason, it has been proposed to add various sensitizers. For example, JP-A-58-F391B9, JP-A-58-161
No. 89, JP-A-58-5686, JP-A-58-110
No. 86 and the like include various waxes, fatty acid amines P, alkylated biphenyls, substituted biphenyl alkanes, coumarin compounds, diphenylamines, and the like. Further, surface treatments have been applied to increase the smoothness of the heat-sensitive layer to increase heat sensitivity, but the effect has been insufficient. Also, it melts due to heating during recording and adheres to the thermal head, etc., resulting in residue and sticking. There is a strong desire for a better solution to this problem, which significantly impairs running performance and the clarity of the wheels.

An object of the present invention is to solve the above-mentioned conventional drawbacks,
In particular, it is an object of the present invention to provide a heat-sensitive recording material that can record clear colored mrs of density holes with low thermal energy and has high thermal sensitivity without inhibiting the running performance of a thermal head due to adhesion of residue, sticking, etc.

As a result of repeated research aimed at the purpose of the present invention, it has been found that a thermosensitive recording material having a thermosensitive coloring layer containing a colorless or light-colored leuco dye and an organic acid or phenolic substance that causes the leuco dye to develop color when heated, It has been found that the above-mentioned conventional drawbacks can be significantly solved by incorporating a compound represented by the following structural formula f into the layer, and the present invention has been achieved.

0 0 (wherein, X is a substituted or unsubstituted alkyl group having 0 to 10 or 1 carbon atoms, a phenyl group or an ethylene group,
, identical! may also represent an alkyl group, a phenyl group, or an alkyl-substituted phenyl group. ) Such compounds include:
For example, benzyl (m, p, 95°C), 1,1-dibenzoylmethane (k, p, 95°C)% 1,2-dipenzoyl ethane (++a, p.

144°C), 1.11-dibenzoylp 1:l (m, p.

, 1' 67.6℃), 1.4-Cubenzoylbutane (wm,
p.

112°C), 1,5[-dibenzoylpentay (m,
p.

68°C), 1.6- ・dibenzoylhexane (m, p
.

84°C), 1,7-dibenzoylhebutane (m, p.

57℃), 1.8- Cupenzoyl octane (!I,
P.

89°C), benzoylacetone (m, p, 59°C) 4-
t-Butyl dibenzoylmethane (m, p.

100℃), stearoyl benzoylmethane (-, p
, 70°C), 1.2-, :, 7penzoylbenzene (m
, p, 146°C), 1,8-dibenzoylbenzene (m
, p, 100°C), 1,4-dibenzoylpenzene (m
, p, 164°C), 1,4-diacetylbenzene (m
, p, l l 4°C), cuminyl (m, p, 84°C)
trans-1,2-X)benzoylethylene (m, p1
84°C), cis-1,2-dibenzoylethylene (m,
p, 111°C), stearylbenzoylmethane (11,
IP, 67-70°C), etc.

Since the above-mentioned compound exhibits an extremely large effect on the voice sensitivity of the heat-sensitive recording material, it provides a coloring surface gII with lower thermal energy f and higher density than conventional ones. Furthermore, since the coloring start temperature shows a sharp rise in the coloring temperature-coloring density characteristic curve, it is possible to quickly obtain a clear image of the density hole without coloring the surrounding area of the first coloring layer. Furthermore, the compound used in the present invention is less likely to cause debris adhesion or sticking during recording, which would impede the running performance of the thermal head.
Can withstand long-term recording.

In the present invention, conventionally known leuco dyes, organic acids, or phenolic substances constituting the heat-sensitive coloring layer are used, and examples thereof are shown below.

Examples of leuco dyes include triphenylmethane phthalide, fluoran, phenothiazine, indolyl phthalide, spiropyran, leuco auramine, rhodamine lactam, triphenylmethane, triazene, naphtolactam, spirotutaranxanthin series,
There are substances f selected from the group such as azomethine series, benzopyran series, hydroxyphthalate-5y series, and leukoolamine series, and organic acids include stearic acid, sialic acid, maleic acid, tartaric acid, citric acid, benzoic acid, and naphthoate. acid,
4-t-butylphenol, 4-phenylphenol,
Solid organic acids such as 2.2'-2-hydroxydiphenyl, 4.4'-isozolobylidene diphenol, naphthol, 4-hydroxyamotophenone, methyl-4-hydroxybenzoate, salicylic acid, or they and formalin. acidic polymers, phenol-aldehyde polymers,
Phenol-acetylene polymer, rosin-modified maleic acid resin, styrene-maleic anhydride copolymer hydrolyzed product,
The substance f is selected from the group of calzexy I-lyethylene polymer hydrolyzate, vinyl ethyl ether-maleic anhydride copolymer hydrolyzate, ethylene-maleic anhydride copolymer hydrolyzate, and the like.

This will be explained below using examples.

EXAMPLES AND COMPARATIVE EXAMPLES Mixtures having the following compositions were dispersed for 24 hours using a Zeel mill, and equal parts by weight were mixed to prepare thermosensitive color forming liquids.

A liquid B liquid This is a conventional sensitizer! Some wax liquid 0? Prepare as follows.

Solution 0 or in place of the above solution 0, solution D-B having the following composition is prepared and used as the solution for forming the arrangement material of the present invention.

Solution D Solution B `` Solution B Example I A coating solution prepared by mixing equal weights of Solutions A, B, and D was applied to the surface of high-quality paper using a wire parser so that the coating weight after drying was 6 rupees. Thermal paper was prepared by coating and drying the mixture to give the following properties.

Example 2 The same procedure as in Example 1 was carried out by mixing equal weights of A*, B liquid, and B liquid.

Example 8 The same procedure as in Example 1 was carried out by mixing equal weights of liquid A, liquid B, and Flw.

Comparative example I The same procedure as in Example 1 was carried out by mixing equal weights of liquid A and liquid B.

Comparative Example 2 The same procedure as in Example 1 was carried out, except that liquids A, B, and C were mixed one by one.

The temperature coefficient r value of the color density curve due to heating of the thermal paper produced above is shown in the table. The color density is a function of the color temperature 1iT, and there is a linear relationship between the color density and the temperature between the temperature at which color development starts and the temperature at which the color density is almost saturated. The temperature coefficient (r value) of this coloring density is defined as the slope of the straight line with respect to the temperature axis (αD/ctr l. From the table, it can be seen that the slope of the density higher than that of Example 1.2.3 and Comparative Example 1.2 It can be seen that the thermal sensitivity of the heat-sensitive layer is significantly improved.Also, when the heat-sensitive recording material obtained in this way was printed on a thermal printer with a thermal head inside, the density was It was noted that a great black image strength X was obtained, and almost no residue or sticking was observed on the thermal head, and the running properties were superior to those of Comparative Examples 1 and 2.

Procedures Amendment Written by Kazuo Wakasugi, Commissioner of the Patent Office, dated February 1982, 1. Indication of the case, Patent Application No. 15540, issued in 1982, 2, Issued - Name of heat-sensitive recording material 3. Person making the amendment. Related: Patent applicant phone number, 272-, jlJl (large) ＼:1 4. Date of amendment order Voluntary amendment □ ly 5. Number of inventions increased by amendment 7. Contents of amendment 1) Page 7, line 14 ~ Line 15 - "After its preparation, mix □ parts by weight" to "mix it after its preparation and correct it to 1." Polyvinyl alcohol (10% aqueous solution) 30 parts water
□ 50 copies” shall be corrected as follows.゛、・ [Bisphenol A '''' 14 parts Polyvinyl alcohol (10 parts% aqueous solution) 33 parts Calcium carbonate □ 20 parts ・Water ・
3) Page 9, line 6, ``Mix liquids A, B, and D in equal weights'' to ``10 parts of liquid A, 30 parts of liquid B, 20 parts of liquid D, and polyvinyl alcohol. (mix 10 parts of a 10% aqueous solution).''

4) Page 9, line 11, ``Mix liquids A, B, and E in equal weight μ'' to [Liquid A 1
0 parts, 3o parts of liquid B, 2o parts of liquid E, and 10 parts of polyvinyl 9 alcohol (1% aqueous solution) are mixed and corrected as follows.

5) Page 9, line 14, ``Mix liquids A, B, and F in equal weights.'' is changed to ``10 parts of liquid A, 30 parts of liquid B, 20 parts of liquid F, and polyvinyl alcohol, 10 parts of liquid F. % aqueous solution) and amend it as follows. .

6) Page 9, line 17, “mix liquids A and B in equal weight” to “10 parts of liquid A, B1
30 parts and 10 parts of polyvinyl alcohol (10 parts aqueous solution).''

7 Page 9, 1st line from the bottom, "Mix liquids A, B, and C in equal amounts" is changed to "Liquid A 10
part, 3o parts of liquid B, 2o parts of liquid C and polyvinyl alcohol (
Mix 1 part of 10% water □ solution) and amend it as follows.

that's all

Claims (1)

[Scope of Claims] A heat-sensitive recording material having a heat-sensitive color-forming layer containing a combination of a colorless or light-colored basic dye, an organic acid and/or a phenolic substance as a heat-sensitive color-forming component, wherein the color-forming layer contains the following general formula: A heat-sensitive recording material characterized by containing the compound shown in f. (wherein, X is a substituted or unsubstituted alkyl group having θ to 10 carbon atoms, a phenyl group, or an ethylene group,
fjJ M may also represent an alkyl group, a phenyl group, or an alkyl-substituted phenyl group. )