JPS61102499A - Production of high gloss coated paper - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (4) Industrial application fields The present invention relates to a novel method for producing highly glossy coated paper.

(B) Prior art A method for manufacturing highly glossy coated paper, which is usually called cast coated paper, is the wet casting method (for example, a special method of producing a highly glossy finish by pressing a wet coating layer onto a heated finished drum surface having a mirror surface). Publication No. 28-3407, Special Publication No. 38-
25160), a rewet casting method (for example, U.S. Pat.
759847, Japanese Patent Publication No. 48-38005, Japanese Patent Application Laid-Open No. 51-102111), a gel casting method (for example, Japanese Patent Publication No. 1988-1983), a gel casting method in which the wet coating layer is made into a gel state and is pressed against a heated finished drum surface having a mirror surface. No. 38-15751, Japanese Patent Publication No. 40-7207, U.S. Patent No. 337
Methods such as No. 7192 Meisei Sai, % Kokai No. 51-40410) are known.

In both of these methods of manufacturing highly glossy walls M and 1tts, a coating layer mainly composed of pigments and adhesives is pressed into contact with a heat-finished surface having a mirror surface in a wet state, and the mirror surface is transferred to the coating layer in a plastic state. This method involves finishing the paper as a coated paper with a smooth and strong gloss.

(C) Problems to be solved by the invention High-gloss coated paper is used as high-quality printing paper for magazine covers, gravure pages, pamphlets, etc., but offset printing is the mainstream printing method. . However, although a major feature of offset printing is the use of dampening water, this also poses a problem.

Fountain water is an etch solution that is diluted with water and contains acids such as phosphoric acid and chromic acid, salts such as ammonium phosphate and ammonium nitrate, and gum arabic to desensitize fat. It is used to prevent ink from being accepted.

However, the dampening water mixes with ink on the plate during actual printing, and reaches the non-image area of the paper via the non-image area of the blanket from the non-image area of the plate and is absorbed.

This has the negative effect of poor print gloss due to wetting.

In the case of highly glossy coated paper, coated paper, art paper, etc. have a high degree of gloss, so they have a high commercial value and are expensive. Although it is necessary to prevent the deterioration of gloss over water, the current high gloss coated paper is still in an insufficient state and has poor reed and ink finish.

Therefore, in view of the above-mentioned problems, the present invention provides a method for producing highly glossy coated paper that does not reduce gloss due to offset printing.

(9) Means for Solving the Problems The present invention involves coating a support with a coating composition containing a pigment and a casein adhesive as main components, and pressing the coating layer against a heated finishing drum having a mirror surface. When producing high-gloss coated paper, adding an alkyl ketene dimer to the coating composition,
Thru. The alkyl ketene dimer used in the present invention can be represented by the following general formula.

R-CH=C-C-R' 0-C=O Here, R and R' are an alkyl group such as C14 or C□6.

Pigments used in the present invention include inorganic pigments such as clay, Kaori 7, aluminum hydroxide, calcium carbonate, titanium oxide, barium sulfate, zinc white, and satin white, or polyolefin/based plastic pigments such as polystyrene and polypropylene. These organic pigments can be used alone or in combination.

In the present invention, the method of adding the alkyl ketene dimer is extremely important, and the following methods (1) and (2) are recommended.

■ Add alkyl ketene dimer after dissolving adhesive such as casein with acid.

■ Add alkyl ketene dimer after dissolving adhesive such as casein in alkaline solution.

Method (2) is a method in which ammonium nitrate, which is acidic, is added to the dissolved water, an adhesive such as casein is added therein, and after heating and dissolving, an alkyl ketene dimer is added.

Method (2) uses alkaline ammonia and/or
Alternatively, there is a method in which sodium carbonate or the like is added, an adhesive such as casein is added thereto, the alkyl ketene dimer is added after heating and dissolving.

If the order of these additions is reversed, the effects of the present invention will be drastically reduced.

The preferred amount of the alkyl ketene dimer added is 0.1 to 8 parts by weight, preferably 0.3 to 5 parts by weight, per 100 parts by weight of the pigment. If it is less than 0.1 parts by weight, sufficient effects cannot be obtained, and if it exceeds 8 parts by weight, the cast surface will be poor and strong gloss will not be obtained, which is not practical.

Casein is effective as the adhesive used in the present invention, but conjugated diene polymer emulsions such as styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer; acrylic ester and/or methacrylic acid Acrylic East polymer emulsions such as N-combinants or copolymers of esters; vinyl polymer emulsions such as ethylene/vinyl acetate copolymers; or polymers containing functional groups such as carboxyl groups of these various polymers. An aqueous binder such as a functionally modified polymer emulsion;

In the present invention, a highly glossy coated paper composition containing a pigment and an adhesive as main components contains an alkyl ketene dimer, and is applied to a slimy support using an air knife, blade, roll, etc.
A highly glossy coated paper can be produced by coating using a coating method such as a rubber doctor or curtain, and then pressing and finishing the wet @ coating layer on the surface of a heated finishing drum having an interface.

(E) Function When using an alkyl ketene dimer: 1 Simply adding it will not produce its effect; adding the alkyl ketene dimer to a solution of casein as an adhesive will bring about its function. Demonstrated.

When the alkyl ketene dimer is added in a specific ratio in such an addition order, the coating layer of the coated paper becomes stable against water, and a decrease in gloss due to water wetting during offset printing can be prevented.

(F') Examples Examples are shown below, but the present invention is not limited to these examples.

Note that all "parts" below are "parts by weight."

Example 1 Solid content of acidic casein/alkyl ketene dimer 2
A 0% solution (pH 6,2) was prepared as follows.

0 parts of sodium birophosphate as a dispersant to 110 parts of added water
．． After completely dissolving 5 parts of kaolin and adding 100 parts of kaolin and stirring, 90 parts of the above 20% acidic casein alkyl ketene dimer solution and 20 parts of 50% styrene butadiene latex were added and stirred to form a coating composition. did. This coating composition was applied to high-quality paper at a rate of 100 liters/rd with a solid coating amount of 20
? /rr? It was coated with an air knife so that it looked like this. When the layer coated on the above-mentioned high-quality paper is in a wet state, it is pressed (
190 Ky/cm) to obtain a highly glossy coated paper.

Example 2 A solution of alkaline casein/alkyl ketene dimer with a solid content concentration of 20% (P, H8.3) was prepared as follows.

Addition of 108 parts of water and 0 of sodium pyrophosphate as a dispersant.
．． After completely dissolving 5 parts of kaolin and 50 parts of calcium carbonate and stirring, 80 parts of the above 20% alkaline casein/alkyl ketene dimer solution and 20 parts of 50% styrene/butadiene latex were added and stirred. A coating composition was prepared.

This coating composition was applied at 100 f/rr? The plate was coated with an air knife on a high-quality paper so that the solid content coating amount was 2097 mm. Then, while the layer coated on the above-mentioned high-quality paper was in a wet state, it was pressed (190 Kr/cm) against the surface of a heated (100° C.) finished drum having a mirror surface to obtain a highly glossy coated paper.

Comparative Example 1 A solution of acidic casein with a solid content concentration of 20% (PH6.3) was prepared as follows.

Completely dissolve 0.5 parts of sodium pyrophosphate as a dispersant in 117.5 parts of added water, add 7100 parts of Kaori, stir and disperse, and then add the above 20% acidic casein solution 76.
．． 5 parts, 50% styrene butadiene latex 20
A coating composition was prepared by adding and stirring the following parts. This coating composition was applied at 100 t/rr? The solid content coating t is 202 on high-quality paper.
It was coated with an air knife so that it was /-. Then, when the layer coated on the above-mentioned high-quality paper is in a wet state, it is pressed (19QK) onto the heated (100°C) finished drum surface with a mirror surface.
p/cm) to obtain a highly glossy coated paper.

Table 1 shows the results of gloss tests before and after offset printing for the highly glossy coated papers obtained in Performance Examples 1 and 2 and Comparative Example 1.

Table 1 Gloss Comparison ◎: Strong gloss X: Significantly reduced gloss, that is, strong gloss produced in Example 1 and Example 2 of the present invention in which an alkyl ketene dimer was added to the coating composition of the strong gloss coated paper It is clear that the gloss of the coated paper does not decrease at all due to dampening water during offset printing.

(G) Effects of the invention As mentioned above, the highly glossy coated paper produced by the method of adding K, alkyl ketene dimer to the coating composition retains the gloss before printing, especially after offset printing using dampening water. As a result, highly glossy coated paper suitable for various types of printing can be obtained.

Procedural amendment (voluntary) February 7, 1985 1, Indication of the case 1988 Patent Application No. 22s27/No. 2, Title of the invention: Fi/Mr. Relationship with the case of the person who filed the patent application Address: 4-2 Marunouchi Otsu-chome, Chiyoda-ku, Tokyo Name (598) Watatsuri Takesho Co., Ltd. 4, Agent Address: 3-4 Marunouchi, Chiyoda-ku, Tokyo 100 No. 2 Mitsubishi Paper Mills Co., Ltd. Telephone (213) 3641 Showa Year Month Day (1) On page 4, line 6 of the specification, ``Go up to the dampening water'' is amended to ``r by the dampening water''.

(2) Same, page 5, line 1 r　R-CH=　C-C-R' oc=o” rR-CH=C-CH-R' Correct to 0-C=OJ.

Claims (1)

[Claims] 1. A strong gloss finish in which a coating composition containing pigment and casein adhesive as main components is coated on a support, and the coating layer is pressed against a heated finishing drum having a mirror surface. In the manufacturing method of glossy coated paper, the manufacturing method of highly glossy coated paper is characterized by adding the alkyl ketene dimer shown below to the coating composition. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ , where R and R' represent a higher alkyl group. 2. The method for producing a highly glossy coated paper according to claim 1, characterized in that the alkyl ketene dimer is added to the coating composition after dissolving the adhesive.