JPS62222896A - Composition for forming surface layer of support of planographic printing plate - Google Patents

Abstract

PURPOSE:To enhance the hydrophilci property of the surface of support and the close adhesiveness of said support to a photosensitive resin, by only once applying a specific composition to the surface of a base material. CONSTITUTION:A trihydroxysilane compound represented by general formula (I);CH2= CXCOO(CH2)nSi(OH)3 (wherein X is a hydrogen atom or a methyl group and n is an integer of 1-6) (A), the polymerization catalyst for said trihydroxysilane compound (B), polyvinyl alcohol with a saponification degree of 30-60% (C), a crosslinked substance of alkali polyacrylate (D) and an inorg. powder insoluble in an org. solvent (E) are dissolved or dispersed in the org. solvent to prepare a composition. This composition may be prepared, for example, by a method wherein the trihydroxysilane compound being the component (A), the polymerization catalyst for said trihydroxysilane compound being the component (B) and polyvinyl alcohol with the saponification degree of 30-60% being the component (C) are dissolved in the org. solvent, and the crosslinked substance of alkali polyacrylate being the component (D) and the inog. powder insoluble in the org. solvent being the component (E) are added to the resulting solution, and a chelate agent, pigment, a due and thickness, etc., are further added thereto if necessary and the obtained composition is deformation strong stirring.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a composition for forming a support surface layer of a lithographic printing plate, and more specifically to a composition for forming a support surface layer on the surface of a support with a hydrophilic and photosensitive resin. The present invention relates to a composition that is applied to the surface of a substrate to form a surface layer in order to provide adhesive properties.

(b) Problems to be solved by conventional techniques and inventions Conventionally, the surface of the support of lithographic printing plates has been subjected to graining treatment to improve adhesion to photosensitive resins, or to have hydrophilic properties. Various treatments such as immersion treatment in silicate solution etc. have been carried out to improve the quality.

However, performing these various treatments may cause problems with quality stability or quality control.

This has the drawback that the equipment and maintenance require constant integrity, resulting in expensive supports for lithographic printing plates.

Therefore, the present invention aims to improve the hydrophilicity of the support surface and the adhesion to the photosensitive resin by simply applying a specific composition to the surface of the support once.

(c) Means and action for solving the problems, that is, the present invention, provides the organic solvent with (a) general formula (I); In the formula, X represents a hydrogen atom or a methyl group, and n
represents an integer from 1 to 6. ) (hereinafter simply referred to as “
trihydroxysilane compound. ), (b) a polymerization catalyst for a trihydroxysilane compound, and (c) polyvinyl alcohol with an M degree of 30 to 60% (hereinafter referred to as
It is also simply called "polyvinyl alcohol."

); (d) a cross-linked product of an alkali polyacrylic acid salt; and (e) an inorganic powder insoluble in the organic solvent. This relates to a composition for use.

Component (a) used in the present invention is a trihydroxysilane compound represented by the general formula (■). Specific examples of the trihydroxysilane compound include T-methacryloxypropyltrihydroxysilane and γ-acryloxypropyltrihydroxysilane. The component used in the present invention is a polymerization catalyst for a trihydroxysilane compound. Specific examples of this polymerization catalyst include:
Examples include sodium acetate, sodium thiocyanate, triethylenetetramine, trimethylbenzylammonium hydroxide, 1,8-diazabicyclo(5,4°0)undecene-7 or its acetate, and amine compounds. The trihydroxysilane compound becomes a three-dimensional network polymer having a (0-3i-0) structure as a skeleton by its polymerization catalyst, and becomes the base of the surface layer of the support.

The component (c) used in the present invention has a saponification degree of 30 to 60.
% polyvinyl alcohol. If the degree of saponification exceeds 60%, it becomes insoluble in organic solvents, which is undesirable.
If it is less than 0%, the degree of hydrophilicity is low, which is not preferable.

Component (2) used in the present invention is a crosslinked product of an alkali salt of polyacrylic acid. Examples of the alkali salt of polyacrylate include sodium polyacrylate and calcium polyacrylate.

In the present invention, this polyacrylic acid alkali salt is crosslinked with a crosslinking agent. Examples of crosslinking agents include diglycidyl ether compounds such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and glycerin diglycidyl ether, epichlorohydrin, and epibromohydrin.

Heroeboxy compounds such as α-methylepichlorohydrin, aldehyde compounds such as glutaraldehyde and glyoxal, and isocyanate compounds such as 2,4-tolylene diisocyanate and hexamethylene diisocyanate are used. The crosslinked polyacrylic acid alkali salt improves the hydrophilicity of the surface layer of the support and also improves the retention of dampening water.

Component (e) used in the present invention is an inorganic powder insoluble in organic solvents. Inorganic powders that are insoluble in organic solvents may be those that are insoluble in organic solvents or have extremely low solubility, such as zinc oxide, aluminum oxide, antimony oxide, and calcium oxide.

Chromium oxide, tin oxide, titanium oxide, iron oxide, copper oxide, lead oxide, bismuth oxide, magnesium oxide.

Metal or nonmetal oxides such as manganese oxide, salts such as calcium carbonate and calcium sulfate, silicon compounds such as silicon dioxide, kaolin, and bentonite.

Examples include natural pigments such as clay, and various metal powders such as aluminum, iron, and zinc. When an inorganic powder insoluble in an organic solvent is present in the surface layer of a support, it forms fine irregularities on the surface. Further, the particle size of the inorganic powder may be about 320 mesh baths, and the smaller the particle size, the more suitable it is for use in the present invention.

The composition according to the present invention can be obtained by uniformly dissolving or dispersing the above-mentioned components (a) to (e) in an organic solvent. Examples of organic solvents include methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, acetic acid, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, ethyl cellosolve, and butyl cellosolve.

Cellosolve acetate, toluene, xylene, trichloroethylene, chloroform, etc. are used alone or in combination.

In preparing the composition according to the present invention, for example (a)
After dissolving the trihydroxysilane compound as the component, the polymerization catalyst for the trihydroxysilane compound as the component (b), and the polyvinyl alcohol with a saponification degree of 30 to 60% as the component (c) in an organic solvent, the component (d) is dissolved. A cross-linked product of alkali polyacrylic acid salt and an inorganic powder insoluble in an organic solvent as component (e) are added, and if necessary, a chelating agent,
pigment.

Dye, thickener, etc. may be added and vigorous stirring may be performed to defoam.

The quantitative proportions of each component in the composition according to the present invention are preferably as follows. That is, the amount of the polymerization catalyst for the trihydroxysilane compound is sufficient as long as it is sufficient to polymerize the trihydroxysilane compound, and is usually 0.1 parts by weight per 100 parts by weight of the trihydroxysilane compound.
~5 parts by weight. The amount of polyvinyl alcohol is about 50 to 200 parts by weight, more preferably about 80 to 180 parts by weight, per 100 parts by weight of the trihydroxysilane compound. If the amount of polyvinyl alcohol is less than 50 parts by weight, the surface layer tends to be insufficiently hydrophilic, and if it exceeds 200 parts by weight, the surface layer may melt and cause printing stains. The amount of the crosslinked polyacrylic acid alkali salt is about 50 to 200 parts by weight, more preferably about 80 to 150 parts by weight, based on 100 parts by weight of the l-lyhydroxysilane compound.

If the amount of polyacrylic acid alkali salt is less than 50 parts by weight, the ability to retain dampening water on the surface of the support will decrease and the hydrophilicity will tend to decrease, and if it exceeds 200 parts by weight, it will retain dampening water. There is a tendency that the ability to do so does not increase, resulting in uneconomical results. The amount of the inorganic powder insoluble in the organic solvent is about 30 to 150 parts by weight, more preferably 50 to 120 parts by weight, based on 100 parts by weight of the trihydroxysilane compound.
It is about parts by weight. The amount of inorganic powder insoluble in organic solvent is 3
If it is less than 0 parts by weight, irregularities on the surface of the support tend to vary, and halftone dot reproducibility in the image area tends to be poor.

If the amount exceeds 150 parts by weight, the amount of photosensitive liquid that permeates into the support increases, resulting in an increased amount of photosensitive liquid used, which tends to be uneconomical.

As the base material for applying the composition according to the present invention, any material may be used as long as it is inexpensive and satisfies the required performance as a lithographic printing plate, such as aluminum,
Foils or plates made of single metals such as iron, copper, zinc, lead, etc. or alloys thereof; plastic films such as polyester, polypropylene, polyimide, polyacrylonitrile, polycarbonate, polyamide, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyethylene, etc. Or sheet-like molded products, synthetic paper, art paper.

Various materials such as coated paper, cardboard, thin paper, etc. can be used. Metal base materials include aluminum, zinc,
Iron etc. are suitable. As the plastic base material, polyester, polyimide, and polycarbonate, which have relatively high dimensional stability, are suitable. As the paper base material, synthetic paper, coated paper, art paper, and cardboard are suitable.

When applying the cohesive composition of the present invention to a metal substrate,
5-sulfosalicylic acid and ethylenediaminetetraacetic acid for the purpose of enhancing adhesive strength with the base material.

trans-cyclohexane-1,2-diaminetetraacetic acid, butane-1,2,3,4-tetracarboxylic acid, propylenediaminetetraacetic acid, pentamethylenediaminetetraacetic acid, cyclobencune-1,2-diaminetetraacetic acid, cyclohexane-1 , 4-diaminetetraacetic acid, 2
-Hydroxy I-rimethylenediaminetetraacetic acid and other chelating agents may be added to the composition according to the present invention. Furthermore, the substrate does not need to be particularly pretreated prior to application of the composition according to the invention, as long as its surface is not contaminated with oily substances. If necessary, the surface of the base material may be physically treated such as wet or dry honing, ball polishing, brush polishing, etc., or chemically treated such as chemical conversion treatment with acid or alkali to improve the surface ratio of the base material. Of course, there is no problem in increasing the surface area.

(D) Examples Example 1 100 parts by weight of γ-methacryloxypropyltrihydroxysilane was added to an organic solvent prepared by mixing 450 parts by weight of ethyl acetate, 600 parts by weight of ethyl alcohol, and 450 parts by weight of methyl isobutyl ketone. After melting 2 parts by weight of remethylhenzyl ammonium hydroxide and parts by weight of polyvinyl alcohol with a degree of saponification of 55%, 100 parts by weight of a crosslinked product of sodium polyacrylate (manufactured by Sumikagaku@ll, trade name Sumikagel) was dissolved. and particle size 10-15fl
100 parts by weight of silicon dioxide of μ was added and mixed and stirred to obtain a composition.

This composition was applied to a degreased aluminum thin plate (JI
S8-1100, thickness 0.15 fin 5 dimensions 200mm
300 irises) with a #6 bar coater,
Heating at 30°C for 60 seconds to form a surface layer (surface film),
A support for a lithographic printing plate was obtained.

A negative photosensitive resin liquid is applied to the surface of this support, and
After drying in a hot air dryer at 0°C for 1 minute, apply a negative film (test pattern: 175 lines) to the coated surface.

3 to 75% halftone dots) and an ultra-high pressure mercury lamp (electric capacity W).
4 KW) for 30 seconds from a distance of 1 m. Thereafter, it was resolved using a developer to obtain a lithographic printing plate.

In this lithographic printing plate, the hydrophilicity of the non-image area and the adhesive strength of the image area were evaluated, and both were found to be good. The hydrophilicity of the non-image area is evaluated by applying offset ink directly to the non-image area and then pouring water onto that surface to determine whether the offset ink falls off or not. evaluated.

In addition, the adhesion strength of the image area was determined by using a Tipa set low clear breather (wearing wheel i C5-17, load 1000 g), applying offset ink to the wearing wheel, and applying halftone dots (75 lines, screen surface 5 %), and the area was abraded, and the halftone dots were judged to fall off after 1000 wears, and the case where the dots did not fall off was evaluated as good.

When this lithographic printing plate was printed on high-quality paper using a Heidel KORD printing machine, more than 50,000 copies of prints with good image reproducibility and no printing stains were obtained.

Example 2 100 parts by weight of γ-methacryloxypropyltrihydroxysilane, 3 parts by weight of trimethylbenzylammonium, and polyvinyl with an M degree of 40% are added to an organic solvent prepared by mixing 400 parts by weight of acetic acid and 1600 parts by weight of ethyl alcohol. After dissolving 80 parts by weight of alcohol, a cross-linked product of sodium polyacrylate (manufactured by Sumika Kagaku, trade name: Sumikagel)
Titanium oxide 55 with 90 parts by weight and particle size of 10 to 15 mnμ
Add parts by weight and mix.

A composition was obtained by stirring.

This composition was used in the same manner as in Example 1 to obtain a lithographic printing plate. The hydrophilicity of the non-image area of this lithographic printing plate was good, and the adhesive strength of the image area was also good.

Further, when printing was carried out in the same manner as in Example 1, more than 50,000 copies of printed matter with good image reproducibility and no printing stains could be obtained.

Example 3 Ethyl acetate 400w 1i! ? n, ethyl alcohol 60
0 parts by weight, 450 parts by weight of methyl isobutyl ketone, and 100 parts by weight of cellosolve acetate.
- 100 parts by weight of acryloxyprobyl trihydroxysilane, 2 parts by weight of trimethylhensyl ammonium hydroxide, and 10 parts by weight of polyvinyl alcohol with a degree of saponification of 50%.
After dissolving 0 parts by weight, a crosslinked product of sodium polyacrylate (manufactured by Sumitomo Chemical ■) was prepared.

Product name Sumikagel) 50 parts by weight and particle size 10-15 μ
30 parts by weight of barium sulfate were added thereto, mixed and stirred to obtain a composition.

This composition was used in the same manner as in Example 1 to obtain a lithographic printing plate. The hydrophilicity of the non-image area of this lithographic printing plate was good, and the adhesive strength of the image area was also good.

Further, when printing was carried out in the same manner as in Example 1, more than 50,000 copies of printed matter with good image reproducibility and no printing stains could be obtained.

(f) As described in detail of the invention, if the composition according to the present invention is used, the conventional graining treatment, hydrophilic treatment, etc., are no longer necessary, and the composition can be applied to the surface of the base material to make it hydrophilic. It is possible to obtain a support for a lithographic printing plate having a surface layer having excellent properties and adhesion to a photosensitive resin. If a lithographic printing plate obtained using this support is used, it is possible to print a large amount of printed matter with good reproducibility in the image area and with little printing stain.

Claims (1)

[Claims] In an organic solvent, (a) general formula (I); CH_2=CXCOO(CH_2)_nSi(OH)_
3(I) (wherein, X represents a hydrogen atom or a methyl group,
n represents an integer of 1 to 6. ) A trihydroxysilane compound represented by (b) a polymerization catalyst for the trihydroxysilane compound, (c) polyvinyl alcohol with a saponification degree of 30 to 60%,
A composition for forming a surface layer on a support of a lithographic printing plate, characterized in that it is formed by dissolving or dispersing (d) a crosslinked product of an alkali salt of polyacrylic acid, and (e) an inorganic powder insoluble in the organic solvent. .