JPS62215093A - Paper polishing paint composition - 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] [Industrial field of application] A quick-drying resin face is applied to the surface of printing paper to give it a more flat gloss, and endless press processing is used for rolling paper. Regarding the composition.

[Conventional technology and problems to be solved]

In recent years, the in-line and speed-up of the reciprocal varnish coating process and the endless press IJD process have progressed, and acrylic or styrene-acrylic resin faces that dry quickly and have excellent properties such as solon kinging resistance, gloss, and layering properties have been developed. Various methods have been proposed (JP-A-55-22079, JP-A-55-22079,
25455).

Although it is true that these compositions have excellent quick-drying properties on the surface of the coating film, there is a residual amount of organic solvent inside the coating film, and it is particularly susceptible to heat when it is rolled in an endless press in-line after the coating process. This has the disadvantage that residual solvent oozes out and the finished appearance deteriorates.

This drawback can be avoided to some extent by slowing down the line speed or by performing an endless press offline, but this reduces work efficiency and makes it impossible to meet market demands.

[Means for solving problems]

The inventor conducted research to solve the above problems and discovered that a resin face with extremely excellent drying properties can be obtained by a specific combination of resin composition and solvent composition.

That is, the present invention uses 10 to 60ij amount% of styrene (hereinafter referred to as "Q"), 60 to 80% of methyl methacrylate, α
, a copolymer (A) obtained by combining ~10% of β-unsaturated carboxylic acid and 0~20% of other vinyl monomers that can be co-merged with these, and 60~95% of toluene. This is a filter paper polishing coating composition characterized by comprising a mixed solvent of 5 to 40% of an alcohol thread solvent and 0 to 35% of other organic solvents. This will be explained in detail below.

Styrene is relatively inexpensive and is necessary to provide adhesion and gloss to printing paper, but if too much styrene is used, it will have poor release properties from the stainless steel plate during endless pressing. In addition, if it is too small, it may be difficult to check the printed paper.
PIflt has poor scratch resistance.

Too little methyl methacrylate will reduce drying properties,
If the amount is too high, the coating film will become too hard, resulting in poor bending resistance and scratch resistance.

As α,β-unsaturated carboxylic acids, monocarzanoic acids such as acrylic acid and methacrylic acid are effective, but if the drying conditions are changed, such as by extremely shortening the drying time, maleic acid, fumaric acid, etc. Dicarboxylic acids such as itaconic acid have better drying properties, and itaconic acid has the highest drying properties. If the amount used is too large, the solubility in the mixed solvent will be poor and the viscosity of the resin face will increase over time, and the transparency of the coating film will be impaired. No dryness is developed.

Other vinyl single caps that can be copolymerized with these may be added to adjust the hardness of the coating film and give it appropriate bending resistance and durability, but if it is added in large quantities, Blocking resistance and drying properties decrease. Specific examples include (meth)acrylic esters in which the alkyl group has 1 to 8 carbon atoms, vinyl acetate, vinyl propionate, vinyl chloride, vinylidene chloride, and the like.

In mixed solvents, as the amount of α,β-unsaturated carboxylic acid increases, increasing the ratio of alcohol-based solvent improves the dissolving property, but if the ratio is too high, the solubility of the resin is adversely affected, and the resin The solution may become dull or the gloss of the coating film may decrease. If it is too small, the desired drying effect cannot be obtained. Among alcoholic solvents, isopropyl alcohol is preferable considering the volatility balance with toluene etc. and price. The desired drying properties can be obtained with a mixed solvent of toluene and alcohol disintegrating agent, but the presence of the sixth component a! i as an e-solvent! r+-[Acetate esters such as methyl and ethyl acetate and ketones such as acetone and methyl ethyl ketone may be used in combination, but if too much, the solubility of the resin may become too good and drying properties may deteriorate. There is.

The method of polymerizing the above-mentioned single needle body includes b liquid, bulk, suspended PA&
Although any legal method may be used, the method using one cup of bath liquid is economically advantageous and provides a high-quality target composition.

The ratio of the copolymer to the mixed solvent is determined so as to provide a concentration and viscosity suitable for a coating method such as a roll coater, and is preferably 50:50 to 20:80 by weight.

The coating composition thus obtained may be used as it is or may be added with other resins (e.g. vinyl chloride-vinyl butyrate monomer resin, nitrified cotton, etc.), plasticizers, release agents (e.g. surfactants) to the extent that the original quality is not impaired. , wax, higher fatty acids, etc.) and others.

〔Example〕

The present invention will be specifically explained using Examples and Comparative Examples as indicated by the arrows. In the example, ``bu'' and ``chi'' are standards.

Example 1 60 parts of styrene monomer in an autoclave equipped with a stirrer,
Methyl methacrylate 60s1 Butyl methacrylate 5
After charging 1.5 parts of itaconic acid, 5 parts of itaconic acid, 80 parts of toluene, 20 parts of inzolobile alcohol, and 1.5 parts of benzoyl peroxide, the temperature was raised to 75° C. and polymerization was carried out for 20 hours. The obtained compound solution was colorless and transparent and had a concentration of 48.5%.

This bath liquid was diluted to a concentration of 25% with toluene/isopropyl alcohol = 8/2, which is the same as the solvent.
It was used as a mold release agent and cooled to 7 cm ft3% (relative to the resin).

This was coated on offset-printed printing pole paper using a roll coater so that the dry coating thickness was about 5 μm, and then pressed using an in-line endless press. The line speed is 3014/min, the press temperature is 120'C, the load is 25 OK&/crrL2G, and the drying zone is 5.
Only a short drying time of 2 m at 0°C was sufficient.

The coating properties are shown in the table.

The concentration of the bath solution after polymerization is 47-49%, and the quality is 25%.
It was diluted with an additive having the same composition as the solvent at 1 cup so that

Shows coating film properties on clothing.

[Effects of "Hatsu 9"] 1) Since the amount of solvent remaining in the coating film is small even after slight drying, the finish is beautiful even when using a high-speed in-line endless press e.

2) E properties such as gloss, blocking resistance, mold release, adhesion, and scratch resistance are also comparable to conventional products.

Claims (3)

[Claims] (1) Styrene 10-60% by weight, methyl methacrylate 30-80% by weight, α,β-unsaturated carboxylic acid 3-1
0% by weight and 0 other vinyl monomers that can be copolymerized with these
From a copolymer (A) obtained by polymerizing ~20% by weight and a mixed solvent (B) of 60 to 95% by weight of toluene, 5 to 40% by weight of an alcoholic solvent, and 0 to 35% by weight of other organic solvents. A paper polish coating composition characterized by: (2) The composition according to claim 1, wherein the α,β-unsaturated carboxylic acid is itaconic acid. (3) The composition according to claim 1, wherein the alcohol solvent is isopropyl alcohol.