JPS5836494A - Base material for electrophotographic type lithographic plate - Google Patents

Abstract

PURPOSE:To provide a base material excellent in the printing durability which prevents inter-layer separation by arranging an opto-electronic photosensitive layer on an aluminum foil of a specified aluminum-foil laminated paper directly or through an anchor layer or an intermediate layer. CONSTITUTION:A photosensitive layer made up of an inorganic photoconductor powder dispersed in an insulating binder resin is provided on aluminum foil of an aluminum laminated paper exceeding 40 dyne/cm of wetting constant in the surface of the aluminum-foil directly or through an anchor layer and/or an inter- mediate layer to obtain a base material as expected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a base material for electrophotographic lithographic printing original plate 494
related.

Generally, electrophotographic lithographic printing original plates are constructed by providing a layer containing an inorganic or organic optical semiconductor on a base material having characteristics such as water resistance and conductivity.

Sheet-like materials such as paper, metal foil, and film are used as the base material, but when paper is used, it is usually treated as a conductive agent to make it waterproof and to make it easier to hold electrophotographic images. sodium chloride.

Inorganic electrolytes such as potassium chloride and calcium chloride.

Alternatively, a coating layer containing an organic polymer electrolyte such as a quaternary ammonium salt is provided.

However, when a lithographic printing original plate is made from paper that has been thoroughly embedded in this way, it is unavoidable that the plate stretches due to the application of dampening water during printing, even if water-resistant treatment has been applied. This causes problems such as wrinkles on the plate during printing, misalignment of printed matter, and irregularly sized ruled lines. .

It has been found that water resistance can be achieved by using paper laminated with metal foil such as aluminum, zinc, or steel instead of paper, and by placing the metal foil layer between the photosensitive layer and the paper. A printing original plate with good dimensional stability can be obtained. (For example, Tokuko Sho 38-17249.Sho 41-24
26. Publication No. 41-12452).

Among metal foil laminated papers, one in which the metal foil is aluminum is generally well known and is called aluminum foil laminated paper (hereinafter referred to as Al 525 paper).

Aluminum paper usually uses vinyl acetate resin or acrylic resin as the adhesive layer between aluminum foil and paper.

Polyolefin resins, urethane resins, phenol resin-containing rubber resins, etc. are used alone, in a mixture, or in a copolymerized state.

These can be used as water-based paints in the form of emulsion, or as solvent-based paints by selecting a suitable solvent.

Methods using water-soluble resins such as casein and poval as adhesives, hot melt methods and extrusion coating methods using wax resins, polyolefin resins, etc. are also well known.

However, as a result of detailed research by the present inventors using such Al 428 paper as a base material, it was found that it had the following serious defects. That is, when an electrophotographic printing original plate was prepared in which an electrophotographic photosensitive layer was provided directly on aluminum foil or via a single layer and/or an intermediate layer, and printing was performed, aluminum foil, an intermediate layer, Alternatively, peeling from the photosensitive layer was extremely likely to occur, and sufficient and practical printing durability could not be obtained.

The present invention aims to solve the above problems and provide a base material for an electrophotographic lithographic printing plate having excellent printing durability.

The present inventors obtained various types of commercially available Al-428 papers, created electrophotographic lithographic printing original plates, and examined the printing durability. We conducted repeated experiments to find out.

As a result, it was discovered that the oxidation and contamination state of the aluminum foil surface affects the printing durability, and that there is a close correlation between the wetting index of the aluminum foil surface and the printing durability. has been reached.

The present invention provides an electrophotographic lithographic printing original plate in which a photoconductive photosensitive layer is provided directly or via an anchor layer and/or an intermediate layer on the aluminum foil of an aluminum foil laminated paper. It is characterized by having a wetting index of 40 dyn·/am or more.

Specifically, the wetting index of the aluminum foil surface is 40 d.
If aluminum laminate paper with a thickness of yn·/am or more is used, an electrophotographic lithographic printing original plate exhibiting extremely good printing durability can be obtained. On the other hand, the wetting index of the aluminum surface is 40 dyn・
When aluminum laminated paper smaller than /am is used, the obtained lithographic printing original plate will be exposed to large amounts from the interface between the aluminum layer and the coating layer (intermediate layer or photosensitive layer) before a sufficient number of prints are reached after printing starts. Once peeled off, further printing becomes impossible. That is, the object of the present invention can be achieved by applying a coating layer such as an anchor layer or an intermediate layer while the aluminum foil surface is not oxidized or contaminated and has a sufficient wetting index.

The wetting index is measured by applying a wetting index standard solution (manufactured by Wako Pure Chemical Industries, Ltd.) onto the surface of the aluminum foil.

The single anchor layer needs to be coated with a film on the surface of the aluminum foil, and in practical terms α051/d to 2.011/d
A coating amount of W1, 11 degrees is preferred, but is not limited thereto. The anchor layer has a wetting index of 40 dyn・/a
Aluminum foil surface of m or more? [The material is not particularly limited, as long as it can be coated with K to form a film. An example would be something like the following.

(1) A polymeric substance that is soluble in water, hot water, an acidic aqueous solution, or an alkaline aqueous solution, and that forms a film when applied to the surface of an aluminum foil. Examples include starch, modified starch, polyvinyl alcohol, water-soluble acrylic resin, alginates, casein, gelatin, cellulose derivatives, isozotylene copolymers, and other water-soluble synthetic resins.

(2) A substance that forms a film when applied to the surface of aluminum foil, which is a so-called emulsion or latex, which is a synthetic polymer substance dispersed in the form of fine particles in water or other media.

Examples of this polymeric material include vinyl acetate resin and polyvinyl butyral as vinyl resins.

Vinyl chloride resin, vinyl chloride-vinyl acetate resin.

Acrylic resins such as vinylidene chloride resin, vinyl fluoride resin, polyvinyl formal, :) allyl phthalate resin, polyacrylic acid ester, polymethacrylic acid ester, polymethyl-α-lyp-roacrylate, etc., and acryl-nitrile resin such as Polyacrylic a 2) Lyle, polybutadiene-7, olefin resins such as crylonitrile, polypropylene, polyethylene/polybutene, etc., styrene resins [acrylonitrile-loosetadiene-styrene resins].

Polyptadiene-styrene resin, polystyrene.

In addition to these, examples include styrene-7 chloride resin, styrene-butadiene resin, styrene-rubber resin, and polyamide resin, polyethylene terephthalate resin, urethane resin, and the like. Furthermore, two or more of these may be used in combination or by copolymerization.

(3) A polymeric substance that is soluble in known organic solvents such as aromatic, alcohol, ester, and hydrocarbon solvents and forms a film when applied to the surface of aluminum-4 foil.

Examples of this polymeric substance include most of the substances described in (2) above.

Among the above substances, those that have good adhesion to the aluminum foil surface or the intermediate layer (or photosensitive layer if no intermediate layer is provided), and do not inhibit light attenuation during plate making and do not interfere with the formation of beautiful images. Use one type of substance or a combination of two or more types.

Adhesion here refers to the bonding between the anchor layer and the layer in contact with it in any process 11 in which the base material is processed into a lithographic printing original plate, plate-made, and then mounted on a printing machine and folded in the gripper. Refers to a state in which there is no peeling.

It also means a state in which, during printing, a vertical force is repeatedly applied to the original plate due to ink tack, but no peeling occurs between one anchor layer and the layer in contact with it within the range of the required number of prints.

Providing a single layer of weighted anchors as described above in the production of an electrophotographic lithographic printing original plate using Fullmirami paper as a base material raises concerns about the following two points, but both can be resolved, and these problems are important to the meaning of the present invention. It does not give

The first is that if an excessively high resistance layer exists on the surface of the aluminum foil, the image formation on this master plate is done by electrophotography, which inhibits light attenuation and results in an image with many capri, but this layer is not selected as an anchor layer. Conductive powder such as carbon black, etc.
Inorganic salts represented by salts or double salts of alkali metals and alkaline earth metals, organic acid salts represented by potassium formate, sodium chelate, etc., polyacrylates, polymethacrylates, styrene-maleic acid salts, etc. Polymer salts, polystyrene sulfonate, polyvinylbenzyltrimethylammonium chloride.

Polymer electrolytes represented by poly(N-methylvinylpyridinium chloride), poly(N,N)dimethyl-3,5-methylenepiperidinium chloride, dimethyldiallylammonium chloride-sulfone-copolymer, etc. may be added in an appropriate amount.

The second reason is that the material selected for the anchor layer dissolves or swells and its strength decreases due to soaking water that enters vertically from the surface of the original plate or horizontally from the edges during printing. If the material is such a substance, the coated layer of the original plate will peel off from the anchor layer itself or from the outer layer in contact with the anchor layer before the required number of copies are printed, making further printing impossible. but,
Commonly known urea formaldehyde resins, melamine formaldehyde resins, polyamide formaldehyde resins, glyoxal, kenyl aldehyde resins, epoxy boria Id resins, dialdehyde starches, and metal salts such as chromium zirconium and zinc are commonly used. Appropriate ones may be selected from among various waterproofing agents and used in combination.

In addition to the above-mentioned method in which a water-resisting agent is used in combination, a substance that itself becomes water-resistant, such as self-crosslinking acrylic emulsion, may be used.

Sara K further improves the popping resistance of the anchor,
Clay, calcium carbonate, and aluminum hydroxide are further added to the anchor to improve the electrophotographic method.

There is no problem in mixing pigments such as titanium oxide, Sachino white, and plastic pigments to the extent that they do not inhibit the coverage of the aluminum foil surface with one layer of the anchor.

In the present invention, a lithographic printing original plate is prepared by providing a photosensitive layer directly on the anchor layer or via an intermediate layer.

In addition, in the present invention, the wetting index of the aluminum surface is 40 dyne.
It is also possible to use an aluminum laminated paper having a rating of /am or more as a base material and apply an intermediate layer directly onto the aluminum surface, omitting the one layer of anoka.

In the present invention, the intermediate layer is a commonly known layer provided between the base material and the photosensitive layer, and is composed of a synthetic resin emulsion and/or a water-soluble polymeric material, if necessary. Calcium carbonate.

A common technique is to mix and apply pigments such as aluminum hydroxide, conductive agents, waterproofing agents, etc.

The coating amount of the intermediate layer is determined as appropriate depending on the intended printing durability of this printing plate, but is usually from 2.01/lit to 20.
A range of 1/d is preferred.

In the present invention, the image-receiving layer (photosensitive layer) refers to a layer formed by electrophotography and contains a photosemiconductor as a basic component. Generally, inorganic optical semiconductor powders such as zinc oxide, titanium dioxide, and cadmium sulfide are dispersed in an insulating binder resin, and weighted organic optical semiconductors such as polyvinyl carbazole are known.

The present invention will be specifically explained below using examples.

(Example 1) Commercially available aluminum laminated paper (10 μm aluminum foil laminated on 1 oot/j high-quality paper) was obtained and measured by applying a wetting index standard solution (Wako Pure Chemical II). The wetting index of aluminum surface is 45 dyn・/a
It was m. Add acrylic ester copolymer emulsion (Hoechst Synthesis, Movinyl 987) to this raw material.
(Composition I) was applied at a coating amount of 2.011/wlK (this layer is referred to as an anchor layer).

A printing plate was prepared by the following method using aluminum laminated paper provided with a single layer of strength as a base material. First, a fungal coating layer with the following composition was provided on the surface opposite to the aluminum. The amount of application is 5.
It was set as 011/d. Note that all "parts" represent weight ratios in terms of solid content.

(Nippon Gosei T-550) (Hoechst Synthesis Movinyl M-650) (Dow Chemical ECR-77) Next, an intermediate layer having the following composition was provided on the anchor layer. The coating amount was B, 01/d.

50 parts of clay (Hex 1 synthetic Movinyl DM-772) A photoconductive layer (photosensitive layer) having the following composition was further provided on the intermediate layer.

The coating amount was 221/d.

(Sakai Chemical Sazenx: #2000) (Nippon Reichhold, 7-1021) Rose Bengal
(The sheet obtained in the LI section was heated at 25°C and 50% R.
Dark adaptation was performed for 24 hours in a H atmosphere to obtain an electrophotographic printing original plate.

(Example 2) One layer of anchor having the following composition was coated on the same full 4 laminated paper as in Example 1 at a coating amount of t51/-.

(Composition ■) Polyvinyl alcohol 88 parts (Nippon Gosei T-750') Quaternary ammonium conductive agent 7 parts (Dow Chemical Σ0R-77) Melamine formaldehyde am ss (Sumitomo Chemical Sumirets 61s) Al ξ with this anchor layer provided ! Using paper as a base material, a printing original plate was obtained by pressing in the same manner as in Example 1.

(Example 3) One layer of an anchor having the following composition was coated on the same aluminum laminated paper as in Example 1 so that the coating amount was t 01/wlVc. (Apply after diluting with a mixed solvent of toluene/butyl acetate - 8/2.) (Composition ■) Solvent: Acrylic resin 90 parts (Dainippon Ink Acrydic A-405) Cationic polymer antistatic agent: 10 parts (Soken Chemical, Nirecondo B-176) A printing original plate was obtained in the same manner as in Example 1 using the aluminum laminated paper provided with one layer of anchors as a base material.

(Example 4) Using the same aluminum laminated paper as in Example 1, a printing original plate was obtained in the same manner as in Example 1 except that no anchor layer was provided.

(Comparative Examples 1 and 2) Various types of commercially available aluminum laminate papers were obtained and the wetting index of the aluminum surface was measured, and the wetting index was 58 dyn·/am.

51 dyn·/am were selected, and each printing original plate was obtained in the same manner as in Example 1.

The evaluation results are summarized in the table.

(Method for evaluating original plates) The original plates obtained in the above Examples and Comparative Examples were plate-made using a 175m IC plate-making machine using a predetermined original drawing. The plate surface was thoroughly wetted with absorbent cotton impregnated with an etchant (manufactured by Itic Co., Ltd.), and printed using a Tope-810 printer K. The warm water used during printing was a mixture of the above etchant and water in a ratio of 1:5. The printing ink used was from Itic.

As is clear from the above explanation, according to the present invention, a base material for an electrophotographic lithographic printing original plate having excellent printing durability can be obtained regardless of the presence or absence of an anchor agent and the type thereof. .

Patent applicant Oji Paper Co., Ltd. Representative Patent attorney Masaaki Kobayashi

Claims (1)

[Claims] 1. In an electrophotographic lithographic printing original plate in which a photoconductive photosensitive layer is provided on the aluminum foil of aluminum foil laminated paper directly or through an anoka layer and/or an intermediate layer, A base material for an electrophotographic lithographic printing original plate, which has an index of 40 dyne/am or more.