JPS5912897A - Developer sheet for no-carbon pressure-sensitive recording material - Google Patents

Abstract

PURPOSE:To obtain a developer sheet having a high preventive property to discoloration and fading of color pictures by light and oxidative gases by using a specific styrene-butadiene latex as a binder for the developer layer. CONSTITUTION:A clay mineral having a laminar structure of right tetrahedral silica is acid-treated in such a way that SiO2 content on dry basis (drying at 105 deg.C for 3 hours) is 82-96.5wt%. The dried clay mineral is contacted with an at least partly soluble Al compound and/or Mg compound in aqueous medium and neutralized with an acid or alkali so that hydroxide is formed in case where the compound is one other than hydroxide and that Al and/or Mg is introduced into the clay mineral treated with acid in order to obtain an inorganic developer composed of semi-synthetic solid acids. The developer and a styrene- butadiene latex with dry solids of a solubility of 20-70wt% (in benzene at 20 deg.C for 48 hours) as a binder are dispersed in water to obtain a coating liquid. The coating liquid is coated on a supporter to obtain a developer sheet for no-carbon pressure-sensitive recording material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color developer sheet for carbonless pressure-sensitive recording materials, and more particularly, the dissolution rate of dry solid content in benzene is 20 to 70% by weight when immersed at 20°C for 48 hours. The present invention relates to a color developer sheet containing a styrene-butadiene latex.

Carbonless pressure-sensitive recording materials are known, for example, as described in US Pat. No. 2,712,507, US Pat. No. 2,800,457, and US Pat.
A colorless dye (hereinafter referred to as a coloring agent) having electron-donating properties, adsorption properties, and coloring (coloring) reactivity dissolved in a high-boiling solvent and incorporated in microcapsules, and electron-accepting reactivity;
It is a recording material that is combined with an adsorbent (hereinafter referred to as a color developer) and utilizes a color-forming reaction due to contact between the two.

Conventionally, the microencapsulation method has been carried out by a coacervation method, an in situ method, an interfacial polymerization method, etc., and the coloring agents used include crystal violet lactone and 3-3 bis(p-dimethylaminophenyl). triallylmethane phthalides such as natutalide, 3-(p-dimethylaminophenyl)-3-(2-methylindol-3-yl)-6-cyphthylaminophthalide, benzoyl, anisoyl, pivaloyl of methylene blue, etc. There are four anol derivatives such as 3-diethylamino-6-methyl, which are also used in the present invention.

Examples of high boiling point solvents include alkylnaphthalenos represented by diimpropylnaphthaleno, Schiff') represented by 1-phenyl-l-quinolylethane /l/7/l
/ Aromatic hydrocarbons such as cans, alkylbiphenyls represented by isopropylbiphenyl, other triallyldimethanos, alkylbenozenos, benzylnaphthalefs, diallylalkylenes, allylindanes, etc.Diptyl diphthalate, maleic acid Carboxylic acid ester compounds such as dioctyl, phosphoric acid ester compounds such as tricresyl phosphate; Vegetable oils such as castor oil, soybean oil, and cottonseed oil, or their modified oils; Natural products such as mineral oil. There are high boiling point fractions (consisting of aliphatic hydrocarbons), which are also used in the present invention.

Conventionally known electron-accepting color developers include acid clay as an inorganic solid acid, natural clay minerals such as attapulgite clay, activated clay obtained by treating acid clay with mineral acids, and JP-A-57-
There are "semi-synthetic solid acids" described in Publication No. 15996, and organic acidic substances include various phenolic compounds, novolak type phenolic resins, polyvalent metal salts of aromatic carboxylic acids, etc. A common drawback is that the colored image on the developer sheet changes color and fades due to light and oxidizing gases such as nitrogen oxides in the air.

As a result of extensive research to improve this drawback, the present inventors have developed a styrene-butadiene latex whose dry solid content has a dissolution rate of 20 to 70% by weight in benzene when immersed for 48 hours at 20°C. It has become clear that by using it as a binder in the colorant layer, it is possible to prevent the colored image on the developer sheet from discoloring or fading due to light or oxidizing gases in the air. In particular, the effect is particularly noticeable among the above-mentioned color developers, including inorganic solid acids such as activated clay.
A remarkable finding was found in ``Semi-Synthetic Solid Acids''.

Here, we will explain the difference between activated clay and "semi-synthetic solid acids" among inorganic color developers.
As described in No. 42-8811, etc., acid clay or similar clays are treated with mineral acids to elute alumina, iron, and other basic components that are soluble in acids. The specific surface area is set to 160 m'/f1 or more.

On the other hand, 'semi-synthetic solid acid' is disclosed in Japanese Patent Application Laid-Open No. 57-15996.
It is a new type of inorganic color developer that is a "semi-synthetic solid acid" whose production method was newly proposed in the publication. (Dry for 3 hours at lo5℃) 8 +02
5. Acid treatment to give a content of ρ2 of 82 to 965% by weight. The resulting clay mineral is contacted in an aqueous medium with a compound of magne/ram and/or aluminum that is at least partially soluble in said medium, and if the converting compound is other than a hydroxide, a hydroxide is formed. A color developer for carbonless pressure-sensitive recording materials produced by neutralizing with alkali or acid to introduce magnenium and/or aluminum components into nucleic acid-treated clay minerals, and optionally drying (2). In this specification, this will be referred to as a "semi-synthetic solid acid") The production method is not only new, but also improves the color forming ability of the color former against electron-donating colorless dyes, and maintains color density under high humidity. It is explained that this will result in the following.

In other words, it can be seen as a new type of color developer that compensates for the disadvantage of conventional clay mineral color developers, such as activated clay, in that colored images tend to fade due to moisture.

Here, the present inventors conducted various tests to determine the suitability of the new type of color developer, ``semi-synthetic solid acid,'' for use in color developer sheets for carbon-free pressure-sensitive recording materials. It was observed that the color development ability was improved and the color development density was maintained under high humidity, and it was clearly different from the clay mineral color developer represented by the conventionally known and publicly used activated clay.

Now, the method for measuring the solid content of the styrene-butadieno latex to benzene at 20°C for 48 hours is as follows.3.
Dry at 5℃, and add 10% benzene to 1g of solid content.
Add 0rd, seal, and heat at 20℃ while stirring occasionally.
After standing for 8 hours, the insoluble matter was dried separately and the weight was measured to calculate the weight percent of the dissolved matter.

That is, styrene 7 has a certain range of solubility in benzene.
- It is not stated in any previously known documents or patents that butadieno-based latex has the effect of significantly suppressing discoloration caused by light of a colored image or oxidizing gases such as nitrogen oxides in the air. This is a new fact that I could not have predicted.

In the present invention, the dissolution rate of the solid content of the styrene-butadiene latex, which is effective in preventing discoloration and fading of the colored image on the developer sheet due to oxidizing gases in the source or air, in benzene after immersion at 20°C for 48 hours is as follows: , 20 to 70
If the weight is less than 35 to 55 weight cents (-cents, the dissolution rate is 20 weight cents), the effect of preventing discoloration and fading of the colored image cannot be obtained, and the dissolution rate is 70 weight cents. (If it exceeds 20%, it will cause blanket stains during offset printing. Many small particles and stains will appear on the blanket of the offset printing machine.) Printing workability will decrease, and the printing suitability of the obtained color developer sheet will be poor, making it unsuitable for practical use. isn't it.

In the present invention, the styrene-phriedene-based latex refers to styrene-butadiene latex, styrene-butadiene latex containing methyl methacrylate, etc. A part of the putadieno copolymer is a copolymer modified with organic acid monomers such as itaconic acid, acrylic acid, methacrylic acid, fumaric acid, maleino acid, vinylbenzoic acid, and isopropenylbenzoic acid. It's okay.

In addition, the solid content of the latex contains anionic and/or nonionic emulsifiers (e.g., potassium n-dodecylsulfonate, sodium isooctylbenzenesulfonate, lauric acid sodium persulfate, etc.), catalysts (e.g., sodium persulfate, potassium persulfate, ammonium persulfate, hydrogen peroxide, t-butylnohydroboroxide, cumene hydroperoxide azodiisobutyric diamide, etc.), chain transfer agents (e.g., n -dotesyl mercaptan, bromoform, carbon tetrachloride, etc.) are included in the range of amounts commonly used.

The amount of the styrene-butadiene latex of the present invention used is 5 to 40 weight percent, particularly preferably 10 to 35 weight percent of the inorganic color developer. If it is less than 5 parts by weight, it will not be very effective in preventing fading of the colored image, and if it is more than 40 parts by weight, the coloring ability will not be sufficient and the commercial value as a color developer sheet will decrease.

The styrene 7-butadieno latex of the present invention can be used in combination with water-soluble adhesives such as starch, polyvinyl alcohol, carboxymethyl cellulose, and white dextrin.

As mentioned above, the color image is prevented from discoloring or fading due to oxidizing gases such as styrene-butadiene-based carotene oxides having a dissolution rate within a specific range in benzene of the present invention9, and among them, inorganic color developers It has been found that the effect is 9 times greater than the size of the sheet used.

In this way, styrenoptadieno latex is used as the most effective "semi-synthetic solid acid" among the inorganic color developers of the present invention, and air is used as a color developer solution for carbonless pressure-sensitive recording materials. The developer note obtained by applying it to a support such as paper using a knife coater, roll coater, etc. has high coloring ability, does not change the color density under high humidity, and does not cause fading due to sunlight or maximum damage to the color image. The disadvantage of color fading due to oxidizing gases such as nitrogen oxides in the air is eliminated, and there is no blanket staining during offset printing, and we have succeeded in obtaining a color developer solution that is highly printable and extremely effective in practice. did.

A method for producing a color former notebook to be used in combination with the color developer sheet of the present invention will be described. All "parts" below indicate parts by weight.

To make a coloring agent notebook for carbonless pressure-sensitive recording materials, 74 parts of crystal violet lactate, 15 parts of benzoyl leucomethyleno blue, and 1 part of malachite green lactone were added to Hysol SAS oil (manufactured by Nisseki Chemical Co., Ltd., a diarylethane-based organic solvent). ) was heated and dissolved in 100 parts to obtain an oily liquid. I) H9
, 5, and the melamine-formalin initial condensate obtained by heating and dissolving was added to the above emulsion and stirred, and the mixture was reacted at 75° C. for 90 minutes. After cooling, the pH was adjusted to 9.5 with caustic soda to obtain a microcapsule dispersion.

After adding 25 parts of wheat starch and 150 parts of oxidized starch (7) 10·c-cent aqueous solution to 100 parts of the microcapsule dispersion (solid content) and stirring and dispersing well, 40 y /
A coloring agent sheet was prepared by applying the color former to m'' high-quality paper using an air knife coater so that the coating amount was st/m' (solid content).

A specific example will be described below.

Production Example 1 10% aqueous solution of oxidized starch in 160 parts of added water
100 parts of a "semi-synthetic solid acid" (manufactured by Mizusawa Kagaku Kogyo ■, trade name Nuruton 88-1) was gradually added to the solution containing the OO part, and after well dispersed, styrene-butadieno latex containing methyl methacrylate ( 20℃ 48 hours va
After adding 20 parts (solid content) (dissolution rate in benzene of 472%) and stirring and dispersing well,
The pH was adjusted to 8.7 with caustic soda to prepare a coating solution. Apply this coating liquid to 40 y/m' high-quality paper at a coating amount of 6 F/m.
' (solid content) using an air knife coater to obtain a developer sheet.

Example 2 A similar preparation was made by replacing the "semi-synthetic solid acid" of Example 1 with activated clay (manufactured by Mizusawa Chemical Industry Co., Ltd., trade name: Jiruton M-140).

Example 3 1i Same procedure except that the styrene-butadiene latex containing methyl methacrylate of Example 1 was replaced in equal amount with a styrene-butadiene latex containing methyl methacrylate having a solubility in benzene of 23.7% by weight when immersed for 48 hours at 20°C. Created in.

Example 4 A product was prepared in the same manner as in Example 1 except that the styrene-butadiene latex containing methyl methacrylate was replaced with an equal amount of leno-butadiene latex at 20°C.

Comparative Example 1 A similar product was prepared by replacing the methyl methacrylate-containing styrene-butadiene latex of Example 1 with an equal amount of methyl methacrylate-containing styrene-phridien latex having a solubility in benzene of 10.9% by weight when immersed at 20°C for 48 hours. .

Comparative Example 2 A similar product was prepared by replacing the methyl methacrylate-containing styrene-butadieno latex of Example 1 with an equal amount of methyl methacrylate-containing styrene-butadieno latex having a solubility in benzene of 82.1% by weight when immersed at 20°C for 48 hours. .

Test Results Table 1 shows the characteristic values after color development using the combination of the color former notebook and the color developer sheet.

The concentration was expressed as a reflectance (percentage).

The 0 fading hues are shown in Table 2.

Table 2 Table 3 shows the blanket stains of the offset printing machine during offset printing of the 0 color developer sheet.

- From Table 1.2.3, the styrene-butadiene latex of the present invention, which has a dissolution rate of 20 to 70% by weight in benzene when immersed at 20°C for 48 hours, is added to activated clay or "semi-synthetic solid acid" as a color developer. By using it to make a color developer sheet, the color image does not deteriorate under harsh conditions such as sunlight and nitrogen oxide gas, and the color hue does not change, and it also has excellent printability. A color developer notebook for carbon recording paper is obtained. In particular, it can be seen that the effect is greatest when used for ``semi-synthetic solid acids''.

Claims (1)

[Scope of Claims] l A carbonless pressure-sensitive recording material that combines microcapsules containing an electron-donating colorless dye and an electron-accepting substance that develops color from the colorless dye, in which a color developer layer has a dry solid content of 20%. A color developer sheet for a carbonless pressure-sensitive recording material, comprising a styrene-phrydien latex having a solubility in benzene of 20 to 70% by weight when immersed for 48 hours at °C. 2. A color developer sheet for a carbonless pressure-sensitive recording material according to claim 2, wherein the color developer is an inorganic solid acid. 3 A clay mineral obtained by acid-treating a clay mineral having a layered structure consisting of regular tetrahedra of silica with an inorganic solid acid so that the 5IO2 content is 82 to 965% on a dry basis (drying at 105 ° C. for 3 hours) in an aqueous medium, at least partially soluble magnesium and/or aluminum in said medium.
Magnesium and/or aluminum components are added to the nucleic acid-treated clay mineral by contacting it with a compound of aluminum and neutralizing it with an alkali or acid to form a hydroxide if this soluble compound is other than hydroxide. 3. The color developer sheet for carbonless pressure-sensitive recording materials according to claim 2, which is a "semi-synthetic solid acid" produced by introducing and optionally drying.