JPS62153365A - Organic solvent type gravure printing ink - Google Patents

Abstract

PURPOSE:To provide the title ink which hardly causes strike-through and has excellent gloss and denseness of its surface, by using a pigment compsn. consisting of an org. pigment treated with a styrene/maleic anhydride resin. CONSTITUTION:0.05-15pts.wt. styrene/maleic anhydride copolymer is added to 100pts.wt. org. pigment such as a phthalocyanine pigment to treat the pigment with the copolymer, thus obtaining a pigment compsn. A resin such as time rosin is blended with said pigment compsn., varnish contg. an org. solvent (e.g., toluene) or vehicle, and anti-foaming agent, wax etc.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Field of Application) The present invention relates to an organic solvent type gravure printing ink, and more particularly, the present invention relates to an organic solvent-based gravure printing ink, and more particularly, the present invention relates to an organic solvent type gravure printing ink, and more particularly, the present invention relates to an organic solvent type gravure printing ink. This invention relates to a gravure printing ink whose permeability is significantly reduced when printing on paper substrates.

(Prior Art) It has been known that the fluidity and gloss of printing inks can be improved by using pigment compositions in which organic pigments are treated with resins, surfactants, etc.

However, with rosin resin, which is commonly used as a resin treatment for organic pigments, although it has improved fluidity and gloss, 2 For example, the solvent used as the substrate for publishing gravure printing ink, which is an organic solvent type, penetrates. Since the penetration of the solvent cannot be suppressed for such paper quality, there are problems such as the gloss and density of the printed matter are significantly poor and double-sided printing is not possible.

That is, when a pigment composition obtained by a conventional processing method such as 9 or above is used in an organic solvent type gravure printing ink, when printing on a low-source paper surface, the pigment penetrates into the back side of the paper.

This results in a phenomenon called see-through.

Problems such as printed matter becoming smudged or not being able to print on both sides occurred. In particular, in recent years, there has been a strong desire to reduce the manufacturing cost of printed materials by changing the paper used for printing from high-quality processed paper to low-quality paper. A problem-free printing ink was needed. In addition, in order to cope with strike-through, the viscosity of gravure printing ink has been adjusted in the past, but viscosity adjustment is not desirable from the viewpoint of printability.

(Problems to be Solved by the Invention) There has been a desire for an excellent organic solvent type gravure printing ink that can solve various problems including strike-through.

[Structure of the invention]

(Means for Solving the Problems) As a result of intensive research to improve the back-extraction, etc., the present inventors found that 0.05 to 15
The inventors have discovered that a printing ink using a pigment composition treated with parts by weight of a styrene-maleic anhydride resin can significantly suppress the penetration of solvents, and have thus come up with the present invention.

Incidentally, as a treatment for pigments, a treatment method using a styrene-maleic anhydride resin is also conventionally known. This pigment composition has been studied mainly for use in writing instrument inks and paints. In particular, it has been shown that pigment compositions treated with water-soluble styrene-maleic anhydride resins have excellent bidispersity and compatibility with vehicle resins in water-based paints, writing instrument inks, and the like.

Additionally, there is a known method of using amine compounds for organic pigments, which may be effective in improving bleed-through, but it is not possible to sufficiently improve bleed-through unless other ingredients are used in combination. difficult.

Examples of the organic pigment of the present invention include soluble azo-based, insoluble Ab-based, phthalocyanine-based, halogenated phthalocyanine-based, anthraquinone-based, perinone-based, dioxazine-based, and quinacridone-based pigments. Pigment derivatives are used in conjunction with pigments if desired.

In the present invention, as the resin for treating the organic pigment, a copolymer of styrene and maleic anhydride, in which the maleic anhydride is partially esterified, is mainly used. The general structural formula is shown below. Note 9
The present invention is not limited to resins having the following structural formula.

However, R represents a hydrogen atom or an alkyl group.

n represents the degree of polymerization.

The amount to be treated is 0.000 parts per 100 parts by weight of organic pigment.
05 to 15 parts by weight is appropriate; if it exceeds 15 parts by weight, there will be no change in permeability, but a problem will occur that the glossiness 9 dispersibility will be poor. Further, if the amount is less than 0.05i parts, it is difficult to obtain the effects of the present invention.

There are no particular restrictions on the treatment method (it may be added during an appropriate step during pigment production).

Generally, the resin is dissolved in aqueous ammonia or a basic aqueous solution of an alkali metal hydroxide and added to the pigment slurry.

Examples of styrene-maleic anhydride resins include:

SMA-1440H (USA ARCO Co., Ltd. 5 weight average molecular weight 2500), Hyros (Seiko Kagaku Co. 1 weight average molecular weight 1
2000), Polymaron (Arayo Kagaku Kogyo Co., Ltd.), and Stylite (Daido Kogyo Co., Ltd.).

The organic solvent type gravure printing ink consists of a colorant (pigment composition), a varnish or vehicle containing a resin and an organic solvent, and additives. As a resin.

Lime rosin, nitrocellulose, chlorinated rubber, giltnite, etc., and toluene as an organic solvent.

Volatile organic solvents such as xylene and hexane.

Additives include antifoaming agents and wax.

The present invention will be explained below with reference to Examples. In the examples, 1 part means part by weight, and 1% means % by weight.

In the example, crude copper phthalocyanine, common salt and polyethylene glycol were added to one goose, kneaded for 5 hours, filtered and washed with water to remove salt and polyethylene glycol, and copper phthalocyanine pigment (C,1, Pigment Blue 15:
3) Obtain the wet cake.

a) The above wet cake is processed in a conventional manner in 2. Dry, crush, and use as a comparative example.

b) Take 100 parts of the above wet cake for pigment.

Stir and disperse in 1000 parts of water. Next, 3 parts of steverite rosin (manufactured by Arayo Kagaku Kogyo, hydrogenated rosin) was added at 1.0%.
After heating and dissolving with 40 parts of IJum aqueous solution, the mixture is added to the pigment slurry and stirred and mixed. Further, hydrochloric acid is added to adjust the pH to 3.0, and the pigment is treated with rosin. Thereafter, this slurry was filtered, and the filtrate was washed with water until it became neutral, and the obtained sea urchin and sea urchin cake was dried and ground in a conventional manner to prepare a comparative example.

C) In the present invention, 100 parts of the above wet cake as pigment is taken and dispersed in 1000 parts of water with stirring. Next, Polymalon 382 (manufactured by Arakawa Chemical Co., Ltd., an ammonia aqueous solution of n-propyl ester of styrene-maleic anhydride copolymer,
Add 3 parts (solid content 40%) and stir. Add hydrochloric acid to adjust pH to 3. This slurry is then filtered and
The filtrate is washed with water until it becomes neutral, and the resulting wet cake is dried and ground in a conventional manner.

A publishing gravure printing ink (lime rosin-toluene system) was prepared using the pigments a), b), and c) and drawn down onto coated paper and non-coated paper using a bar coater. With coated paper, there was no difference in density, gloss, etc. between the two. However, in the case of non-coated paper, C) of the present invention had less paint bleed through compared to a) and was excellent in density and gloss on one surface.

In b), ink strike-through was not improved compared to a), and the density and gloss were also the same as in a).

Example 2 d) 95% of crude copper phthalocyanine and 5% of a phthalocyanine derivative of the following structural formula are mixed and dry milled in a ball mill without mineral substrate.

100 parts of the pulverized material obtained in steps e) and d) are stirred and dispersed in 2000 parts of water. Hyros T-21 (styrene-maleic anhydride resin manufactured by Seiko Chemical Co., Ltd.) is dissolved in aqueous ammonia to create an ammonia solution with a resin content of 10%, and 30 parts of /8 solution is added to the slurry and stirred. 1% calcium chloride solution 1
Add 50 parts, stir, and then add hydrochloric acid to adjust the pH to 3. This slurry was filtered, the filtrate was washed with water until it became neutral, and the resulting wet cake was dried and crushed compared to the conventional method.An ink was prepared in the same manner as in Example 1, and as a result of drawdown, coated paper ), there was no difference in e).

Among non-coated papers, e) of the present invention had less ink bleed through than d) and was superior in density and gloss on the second surface.

Example 3.4 Publication gravure printing inks (chlorinated rubber-toluene system) were prepared using the pigment compositions obtained in Examples 1 and 2, and it was found that on non-coated paper, the pigment composition of the present invention was There was little bleed through and the density and gloss on the first surface were excellent. .

Example 5 185 parts of 6B acid, 40 parts of sodium hydroxide and 4000 parts of water
250 parts of 35% hydrochloric acid was added for acid precipitation. Add 580 parts of a 35% calcium chloride solution to this suspension, adjust the temperature to 0-5°C with water and ice, add 70 parts of sodium nitrite and stir for 1 hour to diazotize.

190 parts of β-oxynaphthoic acid, 10 parts of sodium hydroxide
0 parts were added to 9000 parts of water and melted, and then 120 parts of Roncis 25 (a 25% aqueous solution of disproportionated rosin made by Kao) was added, and the temperature was adjusted to 15°C.The mixture was added to the diazonium salt suspension solution and the pH was adjusted to 11. Coupling at ~11.5. After the reaction is completed, the slurry is heated to 60° C., 10 parts of Polymalon 382 is added, and after treatment, it is filtered, washed with water and dried.

The obtained pigment composition showed less vane ink strike-through in publishing gravure printing ink (lime rosin-toluene type) compared to untreated uncoated paper.

It had excellent density and gloss.

Example 6 130 parts of dichlorobenzidine was tetrazotized, and 7 parts of sodium hydroxide was added to a pigment slurry obtained by compounding 200 parts of a7toacetic acid-〇-toluidide in a conventional manner.
Add 5 parts to make it slightly alkaline.

Next, Rosin Soap 2ON (manufactured by Kao, 20% aqueous solution) 50
Add parts. Add 382.3 parts of polymeron to this slurry, add 20 g of 35% calcium chloride solution, stir, and then add hydrochloric acid to adjust p and H3.

Claims (1)

[Claims] 1. An organic solvent type gravure characterized by using a pigment composition obtained by treating 100 parts by weight of an organic pigment with 0.05 to 15 parts by weight of a styrene-maleic anhydride resin. printing ink. 2. The organic solvent type gravure printing ink according to claim 1, wherein the organic pigment is a phthalocyanine pigment.