JPS59131677A - Color-developing ink for pressure-sensitive copying paper - Google Patents

Abstract

PURPOSE:A color-developing ink for pressure-sensitive copying paper that is composed of a color-developing agent of a reaction product from a specific condensate and a polyvalent metal compound, pigments and organic solvents, thus showing improved color-developing performance and giving bright images with increased light resistance. CONSTITUTION:The reaction between a mixture of p-hydroxybenzoic acid with a p-substituted alkylphenol bearing 1-12C alkyl at a molar ratio of (0.1-5):1 and formaldehyde is carried out in the presence of an acidic catalyst such as phosphoric acid to give a condensate. The resultant condensate is allowed to react with a polyvalent metal compound such as zinc oxide, preferably at a weight ratio of (95:5)-(20:80), preferably at 80-180 deg.C to give an electron-accepting color developer. Then, the color developer is mixed with pigments such as titanium oxide, binders such as acrylic resin and organic solvents such as methyl ethyl ketone to give the objective color-developing ink for pressure-sensitive ink for pressure-sensitive copying paper. USE:For flexographic printing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developer ink for pressure-sensitive copying paper using a novel developer.

Various forms of pressure-sensitive copying paper are known.

In general, it is based on the fact that a leuco dye (hereinafter referred to as a color former), which is an electron donating substance, and an electron accepting substance (hereinafter referred to as a color developer) react to form a layered color substance. That is, a color forming agent is dissolved in a non-volatile solvent, this solution is micro-encapsulated, a clay paper coated on the back side of the entire support, and a lower paper coated on the surface of the support with a color developer are used as a unit, and each When pressure is applied with the coated surfaces facing each other, the capsules coated on the back side of the top paper break and a solution containing the color former completely dissolved oozes out.This is a copy paper that develops color when it comes into contact with the color developer coated on the bottom paper. be.

Also, copying paper which is made by putting 22 bits of upper and lower paper between the middle paper and the lower paper, which are coated with color developer km on the surface of the upper paper, and pressurized in the same way to record 6 sheets, There is a self-coloring type pressure-sensitive copying paper in which the capsule and the color developer are coated on the same paper surface.

These pressure-sensitive copying papers are usually coated with two components, a color former and a color developer, either singly or in combination, over the entire surface of the paper. In order to avoid this, the two components are manufactured either by printing the desensitizing ink on the entire surface to prevent the development of the two colors, or conversely, by applying the above-mentioned two components singly or as a mixture only to the desired areas.

The latter manufacturing method mentioned above is a partial printing method, generally called a spot printing method.

The present invention relates to a color developing ink for flexo/gravure used in spot printing.

Conventionally, color developing inks using clays described in Japanese Patent Publication No. 45-28,430 have been known as color developing inks used in spot printing methods, but these clays have poor color developing ability due to their attributes. This was not desirable because the amount of coating was not sufficient, the coating thickness was increased, and the strong pressure applied during storage and use during stacking caused color development in unnecessary areas, which was undesirable.

Subsequently, in order to avoid adjusting these viscosities, for example, as described in Japanese Patent Publication No. 49-27.134, aromatic carboxylic acids or their anhydrides and a resin in which phenol-formalin resin is dissolved are used. A flexo/gravure ink called a spot ink is disclosed.

However, none of them has yet been satisfactory in terms of color development, light resistance, and plasticizer resistance.

As a result of intensive research on these developing inks for flexographic and gravure printing, the present inventors found that the egg-colored ink for pressure-sensitive copying paper, which is mainly composed of an electron-accepting developer, a pigment, a binder, and an organic solvent, p-hydroxybenzoic acid and p- having an alkyl group having 1 to 12 carbon atoms as a color developer.
A condensate obtained by reacting a substituted alkylphenol with formaldehyde in the presence of an acidic catalyst is mixed or reacted with a polyvalent metal compound, or a condensate obtained by mixing or reacting the condensate with a polyvalent metal compound, and a clay By using a mixture with the above, the coloring performance, the light resistance and sharpness of the colored image are significantly improved, the yellowing resistance of the printed surface is improved and the yellowing caused by the desired oxides is improved, and the color fading resistance caused by plasticizers is improved. I was able to improve my sexuality.

Hereinafter, the present invention will be described in detail and specifically.

The color developer ink for pressure-sensitive copying paper of the present invention is mainly composed of four components: a color developer, a pigment, a binder, and an organic solvent.

First, p-substituted alkylphenols, which are raw materials for forming a color developer, which is a feature of the present invention, the molar ratio of the P-fi-substituted alkylphenol and p-hydroxybenzoic acid,
The conditions for all reaction products such as the formaldehyde source and the polyvalent metal compound are specifically exemplified below.

As the p-alkylphenol building, the substituent is 01 to C1
up to 2 (e.g. p-cresol, I)-ethylphenol, p-isopropylphenol.

p-tert-butylphenol, p-tert-amylphenol, p-tert-octylphenol).

Preferably, those of 04 to 12 are used. By reacting one or more of the above p-substituted alkylphenols with p-hydroxybenzoic acid, the desired condensate + (4) can be obtained.p-
The molar ratio of hydroxybenzoic acid and p-substituted alkylphenol used is p-hydroxybenzoic acid/p-substituted alkylphenol-0.1-5, preferably 0.5-6.

As the formaldehyde source, any formaldehyde source such as formalin and paraformaldehyde can be used as long as it generates formaldehyde under the reaction conditions.

Examples of catalysts include phosphoric acid, hydrochloric acid, oxalic acid, p-toluenesulfonic acid, sulfuric acid, etc. 7).

Formaldehyde/(p-substituted alkylphenol + p
-hydroxybenzoic acid] is usually 0.4 to 1, preferably 0.6 to 0.8. .

Polyvalent metal compounds include oxides, hydroxides, carbonates, basic carbonates, phosphates of zinc, aluminum, titanium, nickel, cobalt, magnesium or calcium;
Examples include silicates and acid salts, with zinc being particularly preferred as the metal, and oxides, hydroxides, and basic carbonates, particularly oxides being preferred as the compound. Considering the polyvalent metal compound, condensate, flatness, and economic efficiency, it is 5:95 to 80:2.
0 is preferred. When reacting a polyvalent metal compound, the reaction temperature is from room temperature to 240°C, preferably from 80 to 18°C.
It is 0°C.

Examples of clays include those having color developing ability, such as kaolin, acid clay, and activated clay. Incidentally, these can also be used as pigments described below. .

Pigments include oxides such as titanium oxide, zinc oxide, magnesium oxide, aluminum oxide, and silicon oxide, hydroxides such as zinc hydroxide and magnesium hydroxide, carbonates such as magnesium carbonate and calcium carbonate, kaolin, and acid clay. Examples include clays such as. Incidentally, the pigment is related to the proper improvement during printing, regardless of the presence or absence of color developing ability.

As a binder, nitrocellulose, acetylcellulose, acetyl phthylcellulose, ethylcellulose, benzylcellulose, cyanide cellulose, hydroxyethylcellulose, methylcellulose, his-10xypropylcellulose, vinyl chloride resin, vinyl acetate resin, vinyl chloride/vinyl acetate resin, Vinylidene chloride resin, vinylidene chloride/vinyl chloride resin, vinylidene chloride/acrylonitrile resin, polyvinyl acetoacetal resin, polyvinyl butyral resin, polyvinyl methyl ether resin,
Acrylic resin, modified acrylic resin, polyester resin,
Polystyrene, α-methyl polystyrene, styrene-α
-Resins such as methylstyrene resin, and copolymers such as ethylene-maleic anhydride, inbutylene-hydrated maleic acid, styrene-maleic anhydride, acetic acid-beam maleic anhydride, and methyl vinyl ether-maleic anhydride.

Examples of organic solvents include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, esters such as methyl acetate and ethyl acetate, and aromatic substances such as toluene and xylene.
Examples include alcohols such as methanol, ethanol, and propatool, ethers and esters of ethylene glycol, and the like.

Hereinafter, the present invention will be specifically explained with reference to Examples. In the examples, "parts" indicate parts by weight.

Example 1 (1) Synthesis of color developer 69 parts p-hydroxybenzoic acid, 138 parts p-tert-zeoctylphenol, 67% formalin 61-
5 parts, p-)luenesulfonic acid, 1 part, and 56 parts of water were placed in a reaction vessel, and after reacting under reflux for 6 hours, they were added to 21 parts of transparent normal lead white, and the reaction size was further reduced under reflux for 1 hour. The hardware was removed and allowed to solidify. 1 This condensate was ground to an average particle size of 2 to 6 μm using a dry pulverizer, and used in the following experiment.

(2) Preparation of color developer ink for flexo/gravure Color developer obtained in (1) above 10 parts titanium oxide
10 parts acrylic resin 2
．． Part 5 Example 2 Preparation of color developing ink for flexo/gravure Example 1 (1
) 10 parts kaolin
5 parts titanium oxide 5 parts acrylic resin 2.5 parts Comparative Example 1 Preparation of color developing ink for flexo/gravure p-phenyl-
Phenol 10 parts Titanium oxide 10 parts Acrylic resin 2.5 parts Methyl ethyl carbon ethanol 36 parts (2:1) Comparative Example 2 Preparation of color developing ink for flexo/gravure p-phenyl-
10 parts phenol 5 parts kaolin 5 parts titanium oxide 5 parts acrylic resin 2.5 parts Color developer ink was used for flexible printing, coating amount (solid content) approximately 5 g/m2
A color developer sheet was obtained by printing on 41 g/m'' high-quality paper so that the color was as follows.

Test methods and evaluation results of various tests on the obtained color developing sheet (
Table 1) is shown.

(1) Color development test A commercially available pressure-sensitive recording paper "Mitsubishi NCR Paper-40" was overlapped with a color developer sheet, and the color was developed through a super calender at a pressure of 10"/arL2. After 24 hours, the total color density was determined. The total blue density was measured using an optical densitometer using a red filter.The higher the value, the greater the color density.

(2) Light resistance test The colored sample obtained in (1) above was irradiated with xenon light for 3 hours using a fade meter, and the density after fading was measured in the same manner.

Note that the higher the numerical value, the greater the light resistance.

(3) Plasticizer resistance test The colored sample obtained in (1) above was made of vinyl chloride (thickness 0.2
”) and heated and stored at 60°G for 1 day and night.

After contacting with a plasticizer contained in vinyl chloride, the blue color density was measured using an optical densitometer using a red filter. Note that the higher the value, the greater the plasticizer properties.

(4) Light resistance yellowing test of uncolored area The sample was irradiated with xenon light for 6 hours in the same manner as in (2) above, and the degree of yellowing was determined using an optical densitometer with a blue filter.

The higher the value, the more advanced the yellowing (・), and the lower the value, the better.

(5) Yellowing resistance test using nitrogen oxides The uncolored developing sheet was left in a container containing 150 ppm nitrogen oxides for 0 minutes, and then the yellow density was measured using an optical densitometer using a blue filter.

The higher the value, the more progressed the yellowing, and the lower the value, the better. In addition, uncolored dark fish are also listed in Table 1 for comparison with yellowing resistance.

As shown in Table 1 above, the color developing ink for flexo/gravure of the present invention has better color development, light resistance, plasticizer resistance, light resistance to yellowing of uncolored areas, and better light resistance than the color development ink shown in the comparative example. It is clear that it has remarkable properties against yellowing due to nitrogen oxides.

Agent: Akira Asamura, 6-1-1 Shinjuku, Katsushika-ku, Tokyo, Mitsubishi Gas Chemical Co., Ltd., Headquarters Laboratory

Claims (2)

[Claims] (1) A developer ink for pressure-sensitive copying paper mainly consisting of an electron-accepting developer, a pigment, a binder, and an organic solvent, in which the developer includes p-hydroxybenzoic acid and an alkyl group having 1 to 12 carbon atoms. A flexo-gravure product characterized in that it is a reaction product obtained by mixing or reacting a condensate obtained by reacting a p-substituted alkylphenol having a group with formaldehyde in the presence of an acidic catalyst with a polyvalent metal compound. Color developing ink. (2) A color developer ink for pressure-sensitive copying paper mainly consisting of an electron-accepting color developer, a pigment, a binder, and an organic solvent, wherein the color developer contains p-hydroxybenzoic acid and an alkyl group having 1 to 12 carbon atoms. p-substituted alkylphenol having a group +e
1. A color developing ink for flexo/gravure, comprising mixing or reacting a condensate obtained by reacting formaldehyde with a polyvalent metal compound in the presence of a neutral catalyst, and mixing the mixture with a clay.