JPS63170079A - Manufacture of color developing sheet for pressure sensitive recording - Google Patents

Abstract

PURPOSE:To improve image color development density and color developing speed by applying a coating solution containing an adhesive prepared mainly of salicylic acid derivative and/or its polyvalent metallic salt as well as starch and/or polyacrylamide on a flat support, and heating a dried developing sheet face at specific temperature. CONSTITUTION:A coating solution containing a solvent such as water is applied on a flat support and a developing face is dried at 100 deg.C-130 deg.C under normal conditions. As salicylate derivatives, for instance, 3, 5-di-tert-butylsalicylic acid, etc., are used. As polyvalent metals, zinc, copper, etc., are available. Further, applicable starches are represented by starch, dextrin, etc. Polyacrylamides are such as acrylamide polymer, etc. It is recommended that solid-phase starch and/or polyacrylamide be used at a weight ratio of 0.1-10 to 1 of salicylic acid and/or its polyvalent metallic salt. Subsequently only when a developing sheet is heated at temperatures of 130 deg.C-240 deg.C, the color developing temperature and density are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Application Field The present invention relates to a method for producing a color developer sheet for pressure-sensitive recording. This invention relates to a method for producing a color developing sheet to be used.

CB) Conventional technology Obtaining a colored image through a contact reaction between an electron-donating, almost colorless organic compound (hereinafter referred to as a color former) and an electron-accepting solid acid (hereinafter referred to as a color developer) has long been practiced. Are known. For example, pressure-sensitive copy paper (e.g., U.S. Pat. Nos. 2,505,470 and 2,5
05,489 specification) and thermal recording paper (e.g.
-14039).

In general, inorganic solid acids such as activated clay, acid clay, and attapulgide have been frequently used as color developers for pressure-sensitive copying paper.

However, these clay-based inorganic solid acids lack stability of colored images against moisture and light.

For this reason, salicylic acid derivatives and/or their polyvalent metal salts have come to be used. Salicylic acid d-conductor polyvalent metal salts have color developing ability by themselves, but salicylic acid derivatives can be used as color developers in combination with polyvalent metal oxides, hydroxides, and carbonates. 52-208
Publication No. 83).

However, these color developers were not sufficient in terms of color development density and color development speed.

(C) Problems to be Solved by the Invention Therefore, the present inventor conducted many tests to improve color density using salicylic acid derivatives and/or polyvalent metal salts thereof, and found that image color density was significantly high. Moreover, the present invention provides a method for producing a color-developing sheeter that has a high color development speed.

(D) Means to Solve All Problems The present invention provides a method for applying a coating liquid containing a salicylic acid derivative and /'- or a polyvalent metal salt thereof, and an adhesive mainly composed of starch and/or polyacrylamide to a flat support. The color developing surface of the applied and dried color developing sheet is heated to 130°C or higher at 240°C.
It is characterized by heating below ℃.

Heating the color developing surface in the present invention refers to coating a flat support with a coating solution containing a solvent such as water at temperatures ranging from 100°C to 100°C under normal conditions.
This refers to drying the color developing surface at a temperature lower than 130°C and then heating the color developing surface to a higher temperature.

That is, heating can be carried out regardless of the shape of the continuous sheet or discontinuous sheet, as long as the coating liquid is applied to the support and dried. For example, immediately after the coating is dried, in the finishing process, or used as a color developer sheet. You can heat it just before cooking. Clays, dispersants, etc. may be added to the color developer sheet as necessary in order to increase the receptivity to color former-containing oil or to improve the liquid properties of the coating liquid.

In the present invention, the color development speed and degree of color development are improved only when the color developing sheet is heated to 130° C. or higher and 240° C. or lower, and they do not improve even if the temperature is higher or lower than that temperature range. The heating time may be within a range that does not discolor the -colored sheet.

The heating method may be any of a variety of methods, such as passing the color developer sheet over a heat roll, blowing hot air onto the color developer sheet, and the like.

The salicylate derivatives used in the present invention include salicylic acid or a benzene nucleus of salicylic acid having 1 to 4 substituents such as alkyl, cycloalkyl, aralkyl, aryl, halogen, hydroxy, etc., or salicylic acid or salicylic acid Examples include polymers of aldehydes and those in which the benzene nucleus has 1 to 3 of the above substituents.

The most typical examples are salicylic acid, 5-tert
-butylsalicylic acid, 3,5-di-tert-butylsalicylic acid, 3,5-di-tert-amylsalicylic acid s 315-di-5ec-butylsalicylic acid, 5-nonylsalicylic acid, 3-methyl-5-ynamylsalicylic acid, 5-ynamylsalicylic acid, 3-cyclohexylsalicylic acid, 5-cyclohexylsalicylic acid, 3.5-dicyclohexylsalicylic acid, 3,5-di(α,α-dimethylbenzyl)salicylic acid, 3.5-dibenzylsalicylic acid, 3- (α,α-dimethylbenzyl)-5-te
rt-butylsalicylic acid, 3-phenylsalicylic acid, 3
．． 5-diphenylsalicylic acid, 3-phenyl-5-te
rt -butylsalicylic acid, 3-benzyl-5-phenylsalicylic acid, 3.5-dichlorosalicylic acid, 3-chloro-5-methylsalicylic acid, 3-chloro-5-ethylsalicylic acid, 3-chloro-5-phenylsalicylic acid, salicylic acid -Formaldehyde polymer, 2,6-dihydroxybenzoic acid-formaldehyde polymer, etc. are used.

All of the above salicylic acid derivatives form salts with polyvalent metals, and the polyvalent metals used include zinc, magnesium, aluminum, titanium, calcium, cobalt,
These include nickel, manganese, tin, and copper. Further, the derivative in the form of an acid that is not a salt and a metal compound may be used in combination.

Starch that can be used in the present invention includes starch, dextrin, dialdehyde starch, phosphate starch, oxidized starch, enzyme-modified starch, a-based starch, cationized starch, etc. Polyacrylamide refers to acrylamide polymer. In addition, it refers to water-soluble products that are mainly composed of acrylamide and copolymerized with acrylic acid ester, acrylic acid, acrylonitrile, etc.

In the present invention, it is not necessary to use adhesives other than starch and/or polyacrylamide, but polyvinyl alcohol, casein, gelatin, carboxymethyl cellulose, styrene-sodium maleate, etc. may be used in combination.

Salicylic acid and/or its polyvalent metal salt of the present invention,
The mixing ratio of starch and/or polyacrylamide is not particularly limited, but if the amount of starch and/or polyacrylamide is too small, it will be sufficient to satisfy the effect of the present invention, and if it is too large, it will be insufficient. Since problems that impede coloring performance are likely to occur, it is preferable that starch and/or polyacrylamide in solid form be 0.1 to 10, preferably 0. It is preferable to use a weight ratio of 5 to 5.

(E) Effect In the present invention, the heating temperature of the color developing surface of the color developing sheet is 13
It is presumed that at temperatures above 0° C., some change occurs in the color developing surface, and as a result, the reaction between the color developer and the dye is significantly accelerated. If the temperature is 130°C or higher, the heating time may be short, but if it is lower than 130°C, for example 120°C, no effect will be obtained even if the heating time is long.

Furthermore, when the heating temperature exceeds 240°C, color development rapidly decreases. This is presumed to be because the salicylic acid derivative and/or its polyvalent metal salt decomposes or sublimates when the temperature exceeds 240°C.

Using an adhesive other than the present invention, such as polyvinyl alcohol, casein, gelatin, carboxymethyl cellulose, styrene-sodium maleate, etc., without using the starch and/or polyacrylamide of the present invention, the developing surface of the color developing sheet 'fr' , even when heated to 130-240℃,
Color development does not improve at all.

Even if a color developer sheet is prepared using starch and/or polyacrylamide as an adhesive and salicylic acid and/or its polyvalent metal salt that has been previously heated to 130 to 240°C and then allowed to cool, the color developer of the present invention will not work. If surface heating is not performed, color development is not the same as above. In addition, even if an adhesive other than the present invention is used and the developing surface is heated, the color development does not improve.
It can be seen that heating only salicylic acid and/or its polyvalent metal salt does not improve color development.

Color development is improved only when the configuration of the present invention is satisfied, but it is unclear what changes occur due to heating of the color development surface.

(F) Example The present invention will be explained in more detail by way of Examples.

In addition, all "parts" in the examples represent "parts by weight."

Comparative Example 1 20 parts of zinc 3.5-di-tert-butylsalicylate was dispersed in 280 parts of an aqueous solution of 1-tibovinyl alcohol, and to this was added 80 parts of calcium carbonate and 1 part of 5-di-tert-butyl sodium phosphate.
0 parts, 4 parts of sodium polyacrylate were added, and the mixture was pulverized in a ball mill for 2 days. Polyacrylamide (product name, PC-600 manufactured by Arakawa Chemical Co., Ltd. solid content 2) was added to this.
0%) was added to prepare a developer coating solution.

40 ? /n? Dry coating amount: 422 on high-quality paper
4? The color developer sheet was prepared by coating the film and drying it at 105°C.

Examples 1 to 6, Comparative Examples 2 to 4 The color developing surface of the color developing sheet of Comparative Example 1 was brought into close contact with a heated hot plate, and the hot plate temperature and contact time with the hot plate were varied under the conditions listed in Table 1. I let it happen.

In both Examples and Comparative Examples, the coating amount of zinc 3,5-di-tert-butylsalicylate was 0.62β.

In order to evaluate the color developer sheets prepared in Examples 1 to 6 and Comparative Examples 1 to 4, commercially available Mitsubishi NCR Paper Blue was stacked so that the coated surfaces faced each other and calender pressure was applied. Fully colored.

Table 1 shows the color densities and their ratios (%) after 1 minute and 24 hours of passing through calender rolls at a nip pressure of 290 Ky/-.

Table 1. Color development test results when the color development sheet was heated on a hot plate Examples 7 to 12, Comparative Examples 5 to 8 20% starch (product The procedure was the same as in Examples 1 to 6 and Comparative Examples 1 to 4, except that 156 parts of MS-4600 manufactured by Nihon Shokuhin Kako Co., Ltd. dissolved in water was used, and each of Examples 7 to 12 and Comparative Examples Examples 5 to 8 were given.

Table 2 shows the results of the tests in Examples 7 to 12 and Comparative Examples 5 to 8.

Table 2. Color development test results when the color development sheet was heated on a hot plate Examples 13 to 18, Comparative Examples 9 to 12 11 - In place of polyacrylamide in Examples 1 to 6 and Comparative Examples 1 to 4, 20 Examples 1 to 6 and Comparative Examples 1 to 6 except that 78 parts of polyacrylamide and 78 parts of 2
4, respectively, Examples 13 to 18 and Comparative Examples 9 to 1.
It was set as 2.

Table 3 shows the results of the tests in Examples 13 to 18 and Comparative Examples 9 to 12.

Table 3. Color developer sheet 't-Hot Grate top 1 part) 121 Examples 19-24, Comparative Examples 13-16 3.5-G tert- of Examples 1-6, Comparative Examples 1-4
3,5-di(α) instead of zinc butylsalicylate.

Other than using zinc α-dimethylbenzyl salicylate,
The same procedures as Examples 1 to 6 and Comparative Examples 1 to 4 were carried out, and these were designated as Examples 19 to 24 and Comparative Examples 13 to 16, respectively.

Table 4 shows the results of the tests in Examples 19-24 and Comparative Examples 13-16.

(Margins below) Table 4. Color development test results when the color development sheet was heated on a hot plate Examples 25 to 30, Comparative Examples 17 to 2° 3,5-G-tert- of Examples 1 to 6 and Comparative Examples 1 to 4
Instead of zinc butylsalicylate, 3.5-diter
The same procedures as Examples 1 to 6 and Comparative Examples 1 to 4 were carried out, except that 20 parts of t-butylsalicylic acid and 1 part of zinc oxide were used, and each of Examples 25 to 30. Comparative Examples 17 to 20 were given.

Examples 25-30. Table 5 shows the results of the tests in Comparative Examples 17 to 20.

Table 5. Color developer test results when the color developer sheet was heated on a hot plate As shown in Tables 1 to 5, the color developer sheet was heated to 130 to 24
If it is not heated to 0°C, the color density is low and the color development speed is not sufficient.

However, as shown in the examples, the color developing sheet of the present invention)
It can be seen that when f is used, both the coloring speed and the coloring density are significantly improved.

(G) Effects of the invention As described above, the color developing sheet manufactured according to the present invention has a faster color development speed and a higher color density than conventional ones, so it can obtain good image density even immediately after printing, and is useful for practical use. It has characteristics that make it easier to read.

Claims (2)

[Claims] (1) A coating solution containing a salicylic acid derivative and/or its polyvalent metal salt and an adhesive mainly composed of starch and/or polyacrylamide was applied to a flat support, and the coated surface was dried at 100°C to less than 130°C. After that, 130 again
A method for producing a color developing sheet for pressure-sensitive recording, the method comprising heating to a temperature of not less than 0.degree. C. and not more than 240.degree. (2) Pressure-sensitive recording according to claim 1, wherein the solid weight ratio of starch and/or polyacrylamide to the salicylic acid derivative and/or its polyvalent metal salt is 1:0.1 to 1:10. A method for producing a color developing sheet for use.