JPS62210477A - Water-soluble composition for forming surface layer of support of lithographic plate - Google Patents

Abstract

PURPOSE:To enable a large number of prints to be printed with good reproducibility by incorporating a water-soluble melamine resin, its hardening catalyst, polyvinyl alcohol, a metal compound capable of coordinating polyvinyl alcohol and forming a chelating compound, a water-insoluble inorganic powder, and metal-phthalocyanine. CONSTITUTION:As the water-soluble melamine resin, a commercial melamine monomer and a melamine prepolymer of a certain polycondensation degree, such as a dimer type resin, may be both used. As the hardening catalyst of the water-soluble melamine resin, an organic amine type catalyst is preferably, and as polyvinyl alcohol, a perfectly saponified type is preferable. As the metal compound, zirconium nitrate is generally used, but other zirconium salts can be used. As the water-insoluble inorganic powder, silicon dioxide superior in hydrophilicness, and capable of being hydrated and dispersed into water in a colloidal state is suitable. The metalphthalocyanine means a phthalocyanine complex salt, and it tends to adsorb a resin wax, oil, and pigments in a developing powder.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to an aqueous solution composition for forming a surface layer of a support for a lithographic printing plate, and more specifically, it relates to an aqueous solution composition for forming a support surface layer of a lithographic printing plate, and more specifically, it relates to an aqueous solution composition for forming a surface layer of a support for a lithographic printing plate. The present invention relates to an aqueous solution composition that is applied to the surface of a substrate to form a surface layer in order to provide excellent properties.

(b) Problems to be solved by the conventional technology and the invention Traditionally, plate making for lithographic printing plates using electrophotographic copying machines involves copying originals onto straight-groove master paper (printing plate material) whose surface has been treated to make it hydrophilic. It is done by doing. Copying of original documents is performed by forming an oleophilic developed powder image on a drum or the like, and then transferring this developed powder image to straight groove master paper. Plate making using an electrophotographic copying machine is a simple plate making method using a copying person that has become popular in recent years, so it is extremely useful in the field of so-called light printing where the reproducibility of the original is not strictly considered and the number of copies printed is relatively small. is of value.

However, the adhesion of the developed powder image to the master paper for straight grooves was poor, and the developed powder image often peeled off during lithographic printing, making it impossible to print a large number of sheets.

By the way, the present inventors previously proposed an invention according to Japanese Patent Application No. 59-233845 for the purpose of improving the hydrophilicity of the support surface of a lithographic printing plate and improving its adhesion to a resin. This prior invention is polyvinyl alcohol.

By applying a composition in the form of an aqueous solution of zirconium nitrate, a water-soluble melamine resin, a curing catalyst for the water-soluble melamine resin, and a water-insoluble inorganic powder to the surface of the substrate, support can be achieved without the need for various conventional treatments. The aim is to improve the hydrophilicity of the body surface and the adhesion to the resin.

The present invention has been made by utilizing the above-mentioned prior invention, and includes improving the hydrophilicity of the support surface of a lithographic printing plate and adhesion of developing powder consisting of a resin face, oil, pigment, etc. to the support surface. This was done for the purpose of improving sexuality.

(c) Means and action for solving the problems, that is, the present invention provides a water-soluble melamine resin, a curing catalyst for the water-soluble melamine resin, polyvinyl alcohol, and a chelate compound that is coordinated with the polyvinyl alcohol. The present invention relates to an aqueous solution composition for forming a surface layer of a support of a lithographic printing plate, characterized by containing a metal compound, a water-insoluble inorganic powder, and a metal phthalocyanine.

The water-soluble melamine resin used in the present invention may be either a commercially available monomer resin or a multimer resin such as a dimer type resin with a certain degree of polycondensation. Examples of curing catalysts for water-soluble melamine resins include ammonium salt catalysts such as ammonium chloride, diammonium phosphate, and ammonium sulfamate, hydrochloric acid or sulfamate salts of organic amino alcohols, dimethylaniline hydrochloride, pyridine-based catalysts, etc.
Examples include hydrochloric acid catalysts, organic amine salt catalysts such as picoline-monochloroacetic acid, and inorganic metal catalysts such as magnesium chloride, zinc chloride, and zinc sulfate.

Among them, it is preferable to use an organic amine salt catalyst. The water-soluble melamine resin becomes a three-dimensional network polymer by its curing catalyst, and becomes the base of the surface layer of the support.

As the polyvinyl alcohol used in the present invention, commercially available fully saponified types, intermediately saponified types, and two-partly saponified types can all be used. It is preferable to use Polyvinyl alcohol is insolubilized by a metal compound that is coordinated to the polyvinyl alcohol to form a chelate compound. Zirconium nitrate is generally used as this metal compound, but other zirconium salts can also be used. Polyvinyl alcohol mainly improves the hydrophilicity of the surface layer of the support.

The water-insoluble inorganic powder used in the present invention may be one that is insoluble in water or has extremely low solubility, such as zinc oxide, aluminum oxide, antimony oxide, calcium oxide, ritted tin quachromide, titanium oxide, Metal or non-metal oxides such as iron oxide, copper oxide, lead oxide, hismuth oxide, magnesium oxide, manganese oxide, calcium carbonate.

Salts such as calcium sulfate, silicon compounds such as silicon dioxide,
Examples include natural pigments such as kaolin, bentonite, and clay, and various metal powders such as aluminum, iron, and zinc. Among these inorganic powders, silicon dioxide, which has excellent hydrophilicity and is hydrated to form a colloid (colloidal silica) and disperse in water, is particularly suitable. When the water-insoluble inorganic powder is present in the surface layer of the 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 metal phthalocyanine used in the present invention refers to a phthalocyanine complex salt, specifically aluminum phthalocyanine and chromium phthalocyanine.

Iron phthalocyanine, cobalt phthalocyanine, 5Iil
Phthalocyanine, potassium phthalocyanine, calcium phthalocyanine, etc. are used. Metal phthalocyanine has the property of easily adsorbing resin face, oil, and pigment in developing powder.

In preparing the composition according to the present invention, for example, polyvinyl alcohol and a metal compound such as zirconium nitrate that is coordinated to the polyvinyl alcohol to form a chelate compound are dissolved in water to prepare a solution A. Separately from liquid A, water-soluble melamine resin and its curing catalyst are dissolved in water to prepare liquid B.
Let it be l. Next, liquids A and B are mixed, water-insoluble inorganic powder and metal phthalocyanine, and if necessary, chelating agents, pigments, dyes, thickeners, etc. are added, and strong stirring is performed to remove the liquid. Just make bubbles.

The quantitative ratio of each component in the composition according to the present invention is about 50 to 200 parts by weight of polyvinyl alcohol to 100 parts by weight of water-soluble melamine resin, preferably 80 to 180 parts by weight.
ffi is the quantity part. 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 metal compound that is coordinated to polyvinyl alcohol to form a chelate compound is 100% of polyvinyl alcohol.
About 2 to 10 parts by weight, preferably 4 to 10 parts by weight, based on parts ii.
The amount is about 7 parts by weight. If the amount of the metal compound is less than 2 parts by weight, the insolubilization of polyvinyl alcohol tends to be incomplete, and if it exceeds 10 parts by weight, when the composition according to the present invention is used as a surface layer of a support, non-image areas may be The surface of the formed support lacks hydration and accepts printing ink, which tends to cause so-called scumming on the plate surface. Further, the amount of the curing catalyst for the water-soluble melamine resin may be sufficient as long as it is sufficient to cure the water-soluble melamine resin, for example, about 0.1 to 5 parts by weight per 100 parts by weight of the water-soluble melamine resin. be.

The amount of water-insoluble inorganic powder is about 30 to 150 parts by weight, preferably 50 parts by weight, based on 100 parts by weight of water-soluble melamine resin.
~120 parts by weight. The amount of water-insoluble inorganic powder is 3
If it is less than 0 parts by weight, the unevenness of the surface of the support tends to vary, and the adhesion to the developing powder tends to vary as well. Further, even if the amount exceeds 150 parts by weight, the degree of unevenness on the surface of the support does not change much, and adding more than that tends to be uneconomical.

The amount of metal phthalocyanine is 100% of the water-soluble melamine resin.
About 10 to 80M parts by weight, preferably 15
~60 parts by weight. The amount of metal phthalocyanine is 1
If it is less than 0 parts by weight, the ability to adsorb developing powder on the surface of the support tends to decrease, and if it exceeds 80 parts by weight, the ability to adsorb developing powder tends not to increase, 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 types of paper, such as coated paper, cardboard, and paper, can be used. Aluminum, zinc, iron, etc. are suitable as the metal base material. As the plastic base material, polyethylene, polyimide, and polycarbonate, which have relatively high dimensional stability, are suitable. Paper base materials include 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 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, cyclopencune-1,2-diaminetetraacetic acid, cyclohexane-1 , 4-diaminetetraacetic acid, 2
- A chelating agent such as hydroxytrimethylenediaminetetraacetic acid 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 specific surface area of the substrate surface can be reduced by physically treating the surface of the substrate by wet or dry hoing, 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゜ First, an aqueous solution composition having the composition shown below was prepared.

Water-soluble melamine resin 100 parts by weight Guanidine sulfamate 0.5 ffiff 1 part Polyvinyl alcohol 100 parts by weight Zirconium nitrate 6 parts by weight Silicon dioxide
100 parts by weight copper phthalocyanine
30 heavy JLfH methylene blue
1 part by weight Aqueous solution leakage rate 20% by weight This composition was applied to a degreased aluminum thin plate (JI
S A-1100, thickness 0.15 crane 9 dimensions 200 crane x 3
00 Tsuru) with a #6 bar coater and heated at 180°C.
The mixture was dried for 3 minutes in a hot air dryer to obtain a support for a lithographic printing plate. An electrophotographic copying machine (
Toshiba Machine @! The original (test pattern; 175 lines, halftone dots 3 to 75%) was copied using IEDM-105H). The composition of the developing powder used for transfer is as follows.

Ethyl acrylate 50 parts by weight Abu-based pigment (Brilliant Carmine 6D manufactured by Dainichiseika Chemical Co., Ltd.)
The lithographic printing plate obtained by transferring 50 parts by weight was transferred to a printing machine (480 manufactured by Ryobi).
When the printer was attached to a mold and printed, approximately 3,000 prints were obtained.

Example 2゜Everything was the same as Example 1 except that the following aqueous solution composition was used.
A lithographic printing plate was obtained under the same conditions as above, and a printing test was conducted.

Water-soluble melamine resin 100 parts by weight Ammonium chloride 0.7 parts by weight Polyvinyl alcohol 77ufB Zirconium nitrate
4M parts titanium oxide
55 parts by weight iron phthalocyanine
50M parts methylene blue 1 part by weight Aqueous leakage rate 15% by weight As a result, Example 2. We were able to obtain approximately 3,500 prints.

Example 3゜Example 1 except that the following aqueous solution composition was used.
A lithographic printing plate was obtained under the same conditions as above, and a printing test was conducted.

Water-soluble melamine resin 100 parts by weight Methylaniline 2 parts by weight Polyvinyl alcohol 67 parts! ! ? ('S Zirconium nitrate 3 parts by weight Barium sulfate
30 parts by weight copper phthalocyanine
15 parts by weight methylene blue
As a result of the IM quantity and aqueous solution concentration of 13% by weight, Example 3. We were able to obtain approximately 3,000 prints.

Comparative Example All Example 1 except that the following p aqueous solution composition was used.
A lithographic printing plate was obtained under the same conditions as above, and a printing test was conducted.

Water-soluble melamine resin 1 part by weight Guanidine sulfamate 0.5 parts by weight Polyvinyl alcohol Part E Zirconium nitrate 6 parts by weight Silicon dioxide
100 parts by weight aqueous solution concentration 20% by weight As a result, in the comparative example, approximately 1,000 prints could be obtained, and after approximately 1,000 sheets, peeling of the developed powder image became noticeable, making it difficult to obtain prints with good reproducibility. I can no longer get it.

As is clear from the above results, the lithographic printing plate support prepared using the aqueous solution composition according to the example has a lower It can be seen that the adhesion to the developing powder is about 3 times better.

(e) Effects of the Invention The support for a lithographic printing plate obtained by applying the aqueous solution composition according to the present invention to a base material has a metal phthalocyanine present in the surface layer of the support and water-insoluble properties on the surface of the support. Since fine irregularities are formed by inorganic powder, it has excellent adhesion with developing powder. Therefore, when printing using a lithographic printing plate obtained by electrophotography, the developed powder image does not peel off, and a large number of printed materials can be printed with good reproducibility.

Furthermore, since hydrophilic polyvinyl alcohol is blended in the aqueous solution composition according to the present invention, a support for a lithographic printing plate having a surface layer with excellent hydrophilicity can be obtained by simply applying it to a substrate. be able to.

Claims (1)

[Claims] Containing a water-soluble melamine resin, a curing catalyst for the water-soluble melamine resin, polyvinyl alcohol, a metal compound that is coordinated to the polyvinyl alcohol to produce a chelate compound, a water-insoluble inorganic powder, and a metal phthalocyanine. An aqueous solution composition for forming a surface layer on a support of a lithographic printing plate, characterized by: