JPH0473717B2 - - Google Patents

Description

Detailed Description of the Invention (a) Field of Industrial Application The present invention relates to a composition for forming a surface layer of a support for a lithographic printing plate, and more specifically to a composition for forming a surface layer of a support on the surface of a support. 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 a lithographic printing plate has been subjected to graining treatment to improve adhesion with photosensitive resin, or to make it hydrophilic. 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, quality control,
The disadvantage is 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 an organic solvent with (a) general formula (); CH ₂ =CXCOO(CH ₂ ) _o Si(OH) ₃ () (wherein, X represents a hydrogen atom or a methyl group, n
represents an integer from 1 to 6. ) (hereinafter simply referred to as "trihydroxysilane compound"), (b) a polymerization catalyst for the trihydroxysilane compound, and (c) polyvinyl alcohol with a saponification degree of 30 to 60% (hereinafter simply referred to as "trihydroxysilane compound"). (Also referred to simply as "polyvinyl alcohol.")
(d) a crosslinked product of an alkali salt of polyacrylic acid; and (e) an inorganic powder insoluble in the organic solvent. This relates to a composition.

The component (a) used in the present invention has the general formula ()
It is a trihydroxysilane compound represented by
Specific examples of trihydroxysilane compounds include:
Examples include γ-methacryloxypropyltrihydroxysilane and γ-acryloxypropyltrihydroxysilane. Component (b) used in the present invention is a polymerization catalyst for a trihydroxysilane compound. Specific examples of this polymerization catalyst include sodium acetate, sodium thiocyanate, triethylenetetramine, trimethylbenzylamimonium hydroxide, 1,8-diazabicyclo(5,4,
0) Undecene-7 or its acetate, amine compounds and the like. The trihydroxysilane compound becomes a three-dimensional network polymer having an (O--Si--O) 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. Saponification degree is 60%
If it exceeds 30%, it becomes insoluble in organic solvents, which is not preferable, and if it is less than 30%, the degree of hydrophilicity is low, which is not preferable.

Component (2) used in the present invention is a crosslinked product of 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; haloepoxy compounds such as epichlorohydrin, epibromhydrin, and 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 that is 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, calcium oxide, chromium oxide, tin oxide, titanium oxide, and iron oxide. , copper oxide,
Metal or nonmetal oxides such as lead oxide, bismuth oxide, magnesium oxide, and manganese oxide, salts such as calcium carbonate and calcium sulfate, silicon compounds such as silicon dioxide, natural pigments such as kaolin, bentonite, and clay, aluminum, iron, Examples include various metal powders such as 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 passes, 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 components (a) to (e) described above 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, butyl cellosolve, cello acetate, toluene, xylene, trichloroethylene, chloroform, etc. are used alone or in combination.

When preparing the composition according to the present invention, for example, the trihydroxysilane compound as the component (a) and the trihydroxysilane compound as the component (b)
After dissolving the polymerization catalyst of the trihydroxysilane compound as the component and polyvinyl alcohol with a degree of saponification of 30 to 60% as the component (iii) in an organic solvent, the crosslinked product of the alkali salt of polyacrylic acid as the component (d) and ( Inorganic powder insoluble in the organic solvent as component (e) is added, and if necessary, chelating agents, pigments, dyes, thickeners, etc. are added, and the mixture is vigorously stirred 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 may be sufficient as long as it is sufficient to polymerize the trihydroxysilane compound, and is usually about 0.1 to 5 parts by weight per 100 parts by weight of the trihydroxysilane compound. 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 lack hydrophilicity, and if it exceeds 200 parts by weight, the surface layer may melt and cause printing stains. The amount of crosslinked polyacrylic acid alkali salt is
For 100 parts by weight of trihydroxysilane compound
The amount is about 50 to 200 parts by weight, more preferably about 80 to 150 parts by weight. The amount of polyacrylic acid alkali salt
If it 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, the ability to retain dampening water will tend not to increase, resulting in failure. It tends to be economical. The amount of inorganic powder insoluble in organic solvent is
For 100 parts by weight of trihydroxysilane compound
The amount is about 30 to 150 parts by weight, preferably about 50 to 120 parts by weight. If the amount of the inorganic powder insoluble in the organic solvent is less than 30 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, iron, copper, zinc, Foils or plates made of single metals such as lead or alloys thereof; plastic films or sheet-like molded products made of polyester, polypropylene, polyimide, polyacrylonitrile, polycarbonate, polyamide, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyethylene, etc. , synthetic paper, art paper,
Various materials such as coated paper, cardboard, thin paper, etc. can be used. Aluminum, zinc, iron, etc. are suitable as the metal base material. 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 composition according to the present invention to a metal substrate, 5%
-Sulfosalicylic acid, ethylenediaminetetraacetic acid, trans-cyclohexane-1,2-diaminetetraacetic acid, butane-1,2,3,4-tetracarboxylic acid, propylenediaminetetraacetic acid, pentamethylenediaminetetraacetic acid, cyclopentane-1, Chelating agents such as 2-diaminetetraacetic acid, cyclohexane-1,4-diaminetetraacetic acid, and 2-hydroxytrimethylenediaminetetraacetic acid may be added to the composition according to the present invention. Furthermore, the substrate does not need to be 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 specific surface area of the substrate surface can be reduced by physically treating the surface of the substrate by wet or dry honing, ball polishing, brush polishing, etc., or by chemically treating it by chemical conversion treatment with acid or alkali. Of course, there is no problem in increasing it.

(d) Examples Example 1 100 parts by weight of a γ-methacryloxypropyltrihydroxysilane compound and trimethyl were 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. 2 parts by weight of benzyl ammonium hydroxide and 100% polyvinyl alcohol with saponification degree of 55%
After dissolving the weight part, add 100% of the cross-linked product of sodium polyacrylate (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumikagel).
100 parts by weight of silicon dioxide having a particle size of 10 to 15 mmμ were added, mixed and stirred to obtain a composition.

This composition was applied to a degreased aluminum thin plate (JIS A-1100, thickness 0.15 mm, dimensions 200 mm x 300
mm) with a #6 bar coater at 230°C.
was heated for 60 seconds to form a surface layer (surface film) to obtain a support for a lithographic printing plate.

A negative photosensitive resin liquid was applied to the surface of this support, and after drying for 1 minute in a hot air dryer at 120°C, a negative film (test pattern: 175 lines,
Halftone dots (3 to 75%) were overlapped and exposed for 30 seconds from a distance of 1 m using an ultra-high pressure mercury lamp (electrical capacity 4 KW).
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 can be evaluated by applying offset ink directly to the non-image area, and then
Water was poured on the surface and judgment was made based on whether the offset ink came off or not, and if it came off, it was evaluated as good. In addition, the adhesive strength of the image area was determined by using a taper type rotary breather (wearing wheel; CS-17, load 1000g), applying offset ink to the wearing wheel, and applying halftone dots (75 lines, 5% mesh area) to the image area. ), and the halftone dots were judged by whether the halftone dots fell off after 1000 wears of that part and the halftone dots were evaluated as good if they did not fall off.

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

Example 2 100 parts by weight of γ-methacryloxypropyltrihydroxysilane, 3 parts by weight of trimethylbenzylammonium, and polyvinyl alcohol with a saponification degree of 40% are added to an organic solvent made by mixing 400 parts by weight of acetic acid and 1600 parts by weight of ethyl alcohol. After dissolving 80 parts by weight, 90 parts by weight of a crosslinked product of sodium polyacrylate (manufactured by Sumitomo Chemical Co., Ltd., trade name Sumikagel) and a particle size of 10
Add and mix 55 parts by weight of ~15mmμ titanium oxide,
A composition was obtained by stirring.

This composition was used in the same manner as in Example 1 to obtain a lithographic printing plate. This lithographic printing plate had good hydrophilicity in the non-image area and good adhesive strength in the image area.
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 An organic solvent prepared by mixing 400 parts by weight of ethyl acetate, 600 parts by weight of ethyl alcohol, 450 parts by weight of methyl isobutyl ketone, and 100 parts by weight of cellosolve acetate,
γ-Acryloxypropyltrihydroxysilane
After dissolving 100 parts by weight, 2 parts by weight of trimethylbenzylammonium hydroxide, and 100 parts by weight of polyvinyl alcohol with a degree of saponification of 50%, a crosslinked product of sodium polyacrylate (manufactured by Sumitomo Chemical Co., Ltd., trade name Sumikagel) was dissolved. ) and 30 parts by weight of barium sulfate having a particle size of 10 to 15 mmμ were added, 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. This lithographic printing plate had good hydrophilicity in the non-image area and good adhesive strength in the image area.
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) Effects of the Invention As explained above, if the composition of the present invention is used, the conventional graining treatment, hydrophilization 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] 1. In an organic solvent, (a) general formula (); CH ₂ =CXCOO(CH ₂ ) _o Si(OH) ₃ () (wherein, X represents a hydrogen atom or a methyl group, and n
represents an integer from 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%, and (d) a crosslinked product of an alkali salt of polyacrylic acid. , (e) an inorganic powder insoluble in the organic solvent; and a composition for forming a surface layer on a support of a lithographic printing plate.