JPS6389379A - Thermal recording material - Google Patents

Abstract

PURPOSE:To enhance color forming sensitivity, by containing a coupler composed of an acidic substance forming a color through the contact with a colorless-light-colored color forming dye and a specific color forming sensitivity improver. CONSTITUTION:A colorless-light-colored color forming dye forming a color by an acidic substance, a coupler composed of the acidic substance forming a color through the contact of said dye and a color forming sensitivity enhancer are contained. As the color forming sensitivity enhancer, an alkyl derivative of oxynaphthoenic ester represented by formula I (wherein R is a 1-9C alkyl group which may be branched and R1 is a 1-9C alkyl group) is used and, concretely, there are 4-propyl-1-oxy-2-naphthoenic ester, 4-butyl-1-oxy-naphthoenic ester or the like. Further, the color forming sensitivity improver is pref. used in an amount of 0.5-100pts.wt. of 100pts.wt. of the coupler. All of the color forming dye, the coupler and the color forming sensitivity improver are used in a fine particulate form.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an SA8 recording material, particularly to a heat-sensitive recording material containing a coloring sensitivity improver that dramatically improves coloring sensitivity.

[Prior Art] Heat-sensitive recording materials usually contain a colorless or light-colored dye, and
0 color is formed by applying a color developer made of an organic acidic substance that is solid at room temperature to the surface of paper together with a binder and other additives, and is achieved by heating or printing using a thermal printer with a built-in thermal head. be exposed.

In recent years, such Ti8. Thermal recording materials are used not only for facsimiles, but also for various printers and POS labels.

Its uses have become extremely wide-ranging, including for tickets. Among these uses, for facsimile, emphasis has been placed on increasing recording speed and improving image quality, that is, increasing density to improve resolution. For this reason, the thermal energy of the thermal head of a recording device tends to become smaller and smaller, and the thermal energy of the thermal recording paper used in such a recording device is
Inevitably, there is a current demand for sufficient color development sensitivity to obtain clear color recording even with a small amount of heat.

In response to these demands, the development of color developers with high color development sensitivity is progressing, while research into color development sensitivity improvers, that is, so-called sensitizers, has been promoted, and recent results include 1, for example, 1984-148688, Japanese Patent Publication No. 58-9828
5, Japanese Patent Publication No. 57-191089. Japanese Patent Publication No. 57-879
93, JP-A-58-87094, JP-A-60-823
82 and Japanese Patent Application Laid-Open No. 60-56588.

However, although the compounds described in these publications have improved the coloring sensitivity of thermal recording paper to a certain extent, none of them have yet fully satisfied the requirements of the above-mentioned industry.

[Problems that IJI is trying to solve] The present invention provides a new color development sensitivity improver that has an unprecedented and superior effect, by incorporating it into a heat-sensitive recording material.
It is an object of the present invention to provide a heat-sensitive recording material with excellent thermal responsiveness, thereby completely solving the concerns in the field regarding the above-mentioned R4 heat recording materials.

[Means for Solving the Problems 1] The present invention provides a colorless or light-colored color-forming dye that develops color with an acidic substance, a color developer comprising an acidic substance that develops color upon contact with the dye, and a color development sensitivity improver. In the heat-sensitive recording material containing 1! of an alkyl derivative of oxynaphthoic acid ester represented by the following general formula as a color development sensitivity improver: ! Or it is characterized by containing two or more types.

It is an SA thermal recording material.

[Function] The heat-sensitive recording material according to the present invention has extremely excellent color development sensitivity. Although the reason for this is not clear, 1. The melt dissolution diffusion rate and saturation solubility of the coloring dye with respect to the compound represented by the general formula CI), which is the coloring sensitivity improver according to the present invention, are extremely high, while the ester of the sensitizer Although these esters do not have the same effect at room temperature, the acidic substance (coloring agent 10) that has been melted and liquefied by heating hydrolyzes the ester more quickly than it reacts with the color-forming dye.

It is thought that the carboxylic acid produced by the hydrolysis reacts with the color-forming material 1 and the color-forming material 2, thereby significantly accelerating the development of color 1.

[Example] Colorless or light colored dye in undeveloped 11 is 1
For example, 3,3-bis(P-dimethylaminophenyl)
-Triarylmethane dyes such as 6-dimethylaminophthalide, diphenylmethane dyes such as 4,4'-bis-dimethylaminobenzhydryl benzyl ether, and 2-luorane dyes such as 7-danitylamino-3-chlorofluorane. Dyes, thiazine dyes such as benzoyl leucomethylene blue, spiro dyes such as 3-methyl-spiro-dinaphthopyran, and other dyes such as leuco auramine dyes, indoline dyes, indigo dyes, etc. .

Further, as the color developer in the present invention, for example, 4-phenylphenol, 4-methyl-2,6-ditert-butylphenol, 4,4'-dihydroxydiphenol, 4-phenylphenol, 4-methyl-2,6-ditert-butylphenol,
．． 4'-isopropylidene diphenol, 4.4'-isopropylidene bis(2-chlorophenol), 4゜4
'-isopropylidene bis(2-methylphenol),
4.4'-isopropylidene bis(2-tert-butylphenol), 4.4'-isopropylidene bis(2,6
-dimethylphenol), 4.4'-2-butylidene diphenol, 4.4'-cyclohexylidene bis(4
-hydroxyphenol), 4.4'-cyclohexylidene bis(2-methylphenol), 4.4'-cyclohexylidene bis(2-isopropylphenol), 2
．． 2'-methylenebis(4-chlorophenol), 2.
2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-bis(4-hydroxyphenyl)hexane, 2.2'-bis(4-hydroxyphenyl)hebutane, 2.2' -bis(4-hydroxyphenyl)octane, 4.4'-thiodiphenol, 4.4'-
Thiobis(3-methyl-6-i3-butylphenol)
, methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, tolylmethyl p-hydroxybenzoate, phenethyl p-hydroxybenzoate, 3-7enylpropyl p-hydroxybenzoate, p-hydroxy Phenyl benzoate, 4-hydroxyacetophenone, 4-hydroxybenzophenone,
Examples include, but are not limited to, salicylic acid anilide.

These color developers are used in an amount of 2 parts by weight per 100 parts by weight of the color forming dye.
It is preferable to use 00 to 3000 parts by weight, especially 500 to 2500 parts by weight.

Next, specific examples of the color development sensitivity improver represented by the general formula (I), which constitutes a main part of the present invention, are as follows.

4-Propyl-1-oxy-2-naphthoic acid methyl ester 4-butyl-1-oxy-2-naphthoic acid ethyl ester 7-tert-butyl-1-oxy-2-naphthoic acid ethyl ester 7-propyl-3- Oxy-2-naphthoic acid butyl ester 7-t-butyl-3-oxy-2-naphthoic acid methyl ester 7-t-butyl-3-oxy-2-naphthoic acid butyl ester 7-t-butyl-3-oxy- 2-naphthoic acid phenyl ester 7-t-butyl-3-oxy-2-naphthoic acid-4'-
t-butylphenyl ester 7-t-butyl-3-oxy-2-naphthoic acid benzyl ester 7-t-butyl-3-oxy-2-naphthoic acid m-
Cresol ester It is preferable to use 0.5 to 100 parts by weight, particularly 1 to 50 parts by weight, of these color development sensitivity improvers per 100 L parts of the color developer.

The above-mentioned chromogenic dye 9wJ coloring agent and coloring sensitivity improver are both used in the form of fine particles, preferably several microns or less. In addition, in order to form a recording layer, as a binder, for example, polyvinyl alcohol, methyl cellulose,
Using a water-soluble binder such as H powder, styrene-maleic acid copolymer, etc., ultraviolet absorbers such as benzophenone and triazole, fillers such as kaolin, talc, and calcium carbonate, lubricants such as polyethylene wax, and various other materials. drugs can be added.

The heat-sensitive recording material according to the present invention is not limited to the coating of the recording layer, and can be coated with a blade coach ink on the surface of a paper material such as paper, plastic film, or synthetic paper. , is formed by applying a coating liquid using air knife coating 1 and drying it.

Next, a specific example will be described.

Example 1 (Liquid A) As a coloring dye, 3-diethylamino-6-methyl-7-phenylaminofuran 3, Ogr and 20g of a 15% aqueous solution of polyvinyl alcohol were dispersed and mixed using a ball mill to obtain a colorless slurry. .

(Liquid B) 8 grams of bisphenol A was added to 10 grams of water and 30 grams of a 15% aqueous solution of polyvinyl alcohol, and the mixture was dispersed and mixed using a ball mill to obtain a slurry.

(Liquid C) 7-1-butyl-3-oxy-2-naphthoic acid methyl ester 3. Polyvinyl alcohol 15 in Ogr
% aqueous solution and 10 gr of water were dispersed and mixed using a ball mill to obtain a slurry.

Mix A, B, C slurry, 50 gr/rn
' Wire bar coater (winding 10.
35 mmφ) so that the thickness after drying was 0.04 mm.

Example 2 (Liquid A) Prepared in the same manner as in Example 1.

(Liquid B) Prepared in the same manner as in Example 1.

(Liquid C) 7-t-butyl-3-oxy-2- of Example 1
Instead of naphthoic acid methyl ester, 7-t-butyl-
3-oxy-2-naphthoic acid phenyl ester 3. Og
r was used.

Both parties obtained thermosensitive recording paper in the same manner as in Example 1.

Example 3 (Liquid A) Prepared in the same manner as in Example 1.

(Liquid B) Prepared in the same manner as in Example 1.

(Liquid C) 7-tert-butyl-3-oxy-2- of Example 1
7-1-butyl-3 instead of naphthoic acid methyl ester
-oxy-2-naphthoic acid butyl ester3. Ogr was used.

Both parties obtained thermosensitive recording paper in the same manner as in Example 1.

Comparative example l (Liquid A) Prepared in the same manner as in Example 1.

(Liquid B) Prepared in the same manner as in Example 1.

(Liquid C) None.

Both parties obtained thermosensitive recording paper in the same manner as in Example 1.

Comparative example 2 (Liquid A) Prepared in the same manner as in Example 1.

(Liquid B) Prepared in the same manner as in Example 1.

(Liquid C) 7-L-butyl-3-oxy-2- of Example 1
Instead of naphthoic acid methyl ester,
Naphthoic acid phenyl ester 3.Ogr was used.

Both parties obtained thermosensitive recording paper in the same manner as in Example 1.

Comparative example 3 (Liquid A) Prepared in the same manner as in Example 1.

(Liquid B) A 7A solution was prepared in the same manner as in Example 1.

(Liquid C) 7-t-butyl-3-oxy-2- of Example 1
3. Salicylic acid phenyl ester instead of naphthoic acid methyl ester. Ogr was used.

Both parties used thermal recording paper in the same manner as in Example 1 (11).

The thermosensitive recording paper prepared as described above was heated at the same time at a temperature of 110°C to reach each coloring start temperature (5% at each temperature).
It was held for a few seconds and judged visually. ) and the relative time until color development is shown in Table 1.

Note that the relative time until color development in Table 1 is based on Comparative Example 1, in which no color development sensitivity improver was added, as 100.

[Effects of the Invention] As is clear from Table 1, the heat-sensitive recording material according to the present invention has dramatically improved sensitivity of the recording layer to thermal energy compared to conventional products, and is fully compatible with high-speed information equipment. It can be used for a wide range of purposes including facsimile, and has great industrial applicability.

Claims (1)

[Scope of Claims] 1. A heat-sensitive product containing a colorless or light-colored color-forming dye that develops color with an acidic substance, a color developer made of an acidic substance that develops color upon contact with the dye, and a color development sensitivity improver. In recording materials, the following general formula (mathematical formula, chemical formula, table, etc.) is used as a coloring sensitivity improver. A good alkyl group, R_1 is an alkyl group of C_1 to C_9, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_2 is H or an alkyl group of C_1 to C_4 ). ] A heat-sensitive recording material characterized by containing one or more alkyl derivatives of oxynaphthoic acid esters represented by: 2. The color developer is 500 to 100 parts by weight of the color-forming dye.
2500 parts by weight of the heat-sensitive recording material according to claim 1. 3. The heat-sensitive recording material according to claim 1, wherein the color development sensitivity improver represented by the general formula (I) is contained in an amount of 1 to 50 parts by weight based on 100 parts by weight of the color developer.