JPH03243392A - Surface treatment method and planographic printing plate - Google Patents

Abstract

PURPOSE:To simplify treatment work, to facilitate the control of surface roughness and to provide an inexpensive surface-treated product of good quality by treating a highly water-absorbable resin and treating an object to be treated with an aqueous solution containing the resin and an etchant. CONSTITUTION:An object to be treated is coated with a treatment solution based on an etchant, a highly water-absorbable resin and water or immersed in said treatment solution to treat the surface of the object to be treated. After surface treatment, the excessive treatment solution is removed. As the object capable of being treated, a metal, glass and plastic are contained and, for example, in the case of use as a plate material for planographic printing, zinc, aluminum, copper or stainless steel can be treated. The usable highly water-absorbable resin is a high-molecular substance showing high water absorbability and there are starch, carboxy methyl cellulose, polyacrylic acid or polyvinyl alcohol. The etchant is selected corresponding to the kind of the object to be treated but, as representative ones, there are sodium hydroxide, hydrogen fluoride, nitric acid or ferric chloride.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application - The present invention relates to surface treatment of metals, ceramics such as glass, and synthetic resins such as plastic films, and particularly relates to a technique for roughening the surfaces.

- Conventional technology - Conventionally, techniques for roughening the surface of metal, especially aluminum plates, include mechanical methods such as ball polishing using polishing sand, plush polishing using a wire brush, electrochemical methods, etc. and chemical methods.

Mechanical methods require a large amount of time and equipment. Electrochemical methods have drawbacks such as low working efficiency, high electricity consumption, and the need for considerable scale equipment. As a chemical method, for example, there is a method using pitting corrosion, etc., but it has drawbacks such as difficulty in controlling roughness.

Problems to be Solved by the Invention - The present invention improves the drawbacks of these conventional techniques, simplifies processing work, enables low cost with simple processing equipment, and provides a surface with easy control of surface roughness. The purpose is to provide a treatment method and enable the provision of inexpensive, high-quality surface treatment products.

Means for Solving a Problem - The above object is achieved by using a super absorbent resin and treating it with an aqueous solution containing the resin and a corrosive agent.

Items that can be treated by the present invention include metals, glass,
This includes almost anything that requires roughening surface treatment, such as plastics.

For example, when used as a planographic printing plate material, lHo,
Aluminum, copper, stainless steel, etc. can be treated according to the invention. The water-absorbing resin that can be used in the present invention is a polymeric substance that exhibits extremely high water absorption, and typical examples include starch, carboxymethyl cellulose, polyacrylic acid, and poval. can include the following resins.

AQUARIATSUKU CA (sodium polyacrylate manufactured by Nippon Shokubai Chemical Industry Co., Ltd.), Acryhope (same as above), AQUA KEEP (sodium polyacrylate manufactured by Seitetsu Kagaku Kogyo Co., Ltd.), ARASORB (polyacrylic KAlium manufactured by Arayo Chemical Co., Ltd.), Sunwet ( Sanyo Chemical Industries starch/polyacrylate graft copolymer), WAS (WATERABSO
RBENTSTARCH, starch/polyacrylate-based graft copolymer manufactured by Nissandono Chemical Co., Ltd.), Sumikagel S type, Igetagel (all acrylic acid/vinyl alcohol copolymers manufactured by Sumitomo Chemical Co., Ltd.), Sumikagel S type (manufactured by Sumitomo Chemical Co., Ltd.) Modified polyethylene oxide [cross-linked polyethylene oxide]), Sumikagel N type (sodium polyacrylate manufactured by Sumitomo Chemical), Aqua Reserve GP, Mizumochi Ichiban (all polyvinyl alcohol/maleic ester type manufactured by Nippon Gosei Chemical Industry) copolymer)
, Kl Gel (isobutylene/maleic anhydride copolymer made by Clary), Lanshield 1 Lanshield FA (all polyacrylate fibers made by Japan Exlan Kogyo), Aquaprene (modified polyethylene oxide made by Meisei Chemical Industry), Gel Fine (carboxymethyl cellulose sodium manufactured by Daicel Chemical Industries).

Corrosive agents are selected depending on the type of object to be treated, and typical examples include the following:

Sodium hydroxide (corrosive for aluminum and acetate films), hydrogen fluoride (corrosive for glass)
, nitric acid (corrosive to zinc), ferric chloride (corrosive to copper), etc.

One of the features of the present invention is that surface roughness can be easily controlled. Examples of surface roughness control means include the following.

1) Selection of corrosive agent 2) Concentration of corrosive agent 3) Adjustment of super absorbent resin concentration 4) Drying temperature 5) Drying time 6 Types of super absorbent resin The present invention will be explained below with reference to Examples.

Example 1 A smooth aluminum plate with a thickness of 0.25 mm is degreased and then coated with the following aqueous solution.

Sodium hydroxide: 12g Sunwet IM 1000 (Sanyo Kasei starch/polyacrylate graft copolymer): 10g Water: After applying IQQOm 1, it was immediately dried at 50°C, washed with water to remove the treatment solution, and dried to obtain a pale white porous membrane.

The center line average roughness R, , was 0.5 μm.

Example 2 The following treatment solution was applied to a smooth aluminum plate having a thickness of 0.25 mm.

Sodium hydroxide: 8g Super absorbent resin (same as Example 1): ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 8
g Water: 1000 mg After coating, immediately after drying at 80° C., the coated layer was removed by washing with water and dried. Center line average roughness R, I = 0.8μ
A uniform rough surface of m was obtained.

Example 3 The following treatment solution was applied to a smooth aluminum plate having a thickness of 0.25 mm.

Sodium hydroxide・・・12g Aqua Keep (sodium polyacrylate made by Japan Shokuhatsu Kagaku Kogyo)・・・・・・・・・・・・15g Water・・・・・・・・・・・・- Immediately after applying 1000 ml, it was dried at 120°C, the excess coating liquid was removed by washing with water, and it was dried. A white porous film was obtained. Centerline average roughness (R, = 1.2 μm).

Example 4 After degreasing a mirror-finished aluminum plate with a thickness of 0.25 mm,
An image was formed on the surface with water-repellent ink, and then the following solution was applied.

Sodium hydroxide: 8g Sumikagel (acrylic acid/vinyl alcohol copolymer manufactured by Sumitomo Chemical): 8g Water: 1000ml Immediately after application, dry at 50°C Then, the excess coating layer was removed by washing with water. After drying, the ink image was removed with a solvent (petroleum, etc.). A negative image with a white background was obtained. In addition,
Screen images of up to 150 lines could be reproduced.

Example 5 A photosensitive resin liquid was applied to the aluminum plate having a partially corroded surface obtained in Example 4. Then, it was washed with water at an appropriate pressure. As a result, the photosensitive resin layer remained only on the roughened white portion, and a lithographic printing plate was obtained. This original plate had a high printing durability, and had a printing durability of more than 200,000 sheets.

Example 6 A smooth aluminum plate with a thickness of 0.25 mm was coated with the following solution.

Sodium hydroxide...8g Super absorbent resin (same as Example 1)...
After applying 8g water・・・・・・・・・1000ml,
Immediately after drying at 120°C, the coated layer was removed by washing with water.

After drying again, a photosensitive resin liquid was applied to the roughened white surface to form a photosensitive layer. A good lithographic printing plate was obtained.

Example 7 A smooth aluminum plate with a thickness of 0.25 mm was coated with the following solution.

Sodium hydroxide...15g Super absorbent resin (same as Example 1)...
After applying 12 g of water, the coating was immediately dried at 120° C., and then washed with water to remove the excess coating layer. After drying again, a photosensitive resin layer was coated thereon. A high-performance screenless lithographic printing plate was obtained.

Example 8 The following solution was applied onto a hard glass plate with a thickness of 3 mm.

Hydrogen fluoride・・・・・・10ml Sumikagel R type (polyethylene oxide crosslinked product made by Sumitomo Chemical Industries)・・・・・・20g Water・・・・・・・・・LOoom 1 application Thereafter, the coating layer was immediately dried at 80° C., washed with water to remove the coating layer, and dried. A roughened glass plate was obtained.

Example 9 An acetate film having a thickness of 0.25 mm was coated with the following coating.

Potassium hydroxide: 20g Super absorbent resin (same as Example 1): 15g Water: 1000m at 180°C After drying, it was washed with water to remove the excess coating layer, and then dried. - An acetate film with a roughened surface was obtained.

Example 1 - An aluminum plate having a thickness of 0.25 mm was coated with the following solution.

Sodium hydroxide: 12g Super absorbent resin (same as Example 1): 10g Water: 1000ml After applying, Immediately after drying at 50°C, the excess coating layer was removed by washing with water.

After drying again, a photosensitive resin layer was applied and formed. A high resolution lithographic printing plate was obtained.

Example 11 The following solution was applied to a smooth aluminum plate with a thickness of 0.25 mm.

Sodium hydroxide: 12g Super absorbent resin (same as Example 1): 10g Water: 1000ml After application The coated layer was immediately dried at 120° C. and washed with water to remove the coated layer. After drying again, patterns and images were formed using water-repellent ink.

A printing plate for simple planographic printing was obtained.

Effects of the Invention The effects or features of the present invention described above are as follows.

a) The surface of an object can be roughened without using mechanical processes.

b) It is not limited by the size or shape of the object, and can process the surface of almost any shape of object.

C) Since the coating formed on the object surface for processing is highly hydrophilic, this layer can be used as a lithographic printing plate subbing layer.

d) Since the treatment liquid is oil-repellent, partial corrosion can be easily performed by masking with oil-based ink.

e) Surface roughness can be easily controlled by changing each parameter.

f) Since the treatment liquid generally has a degreasing ability, pretreatment such as degreasing is not required.

g) Processing costs are extremely low.

Claims (1)

[Scope of Claims] 1) The object to be treated can be treated by applying a treatment liquid containing a corrosive agent, a superabsorbent resin, and water as the main components, or by immersing it in the treatment liquid. A surface treatment method characterized by treating a surface. 2) A surface-treated article obtained by removing excess treatment liquid after surface treatment by applying a treatment liquid containing a corrosive agent, a superabsorbent resin, and water as main components. 3) A surface treatment solution characterized by containing a corrosive agent, a super absorbent resin, and water as main components. 4) The surface treatment method according to claim 1, wherein after treating the object with the treatment liquid, the object is dried, and then the coating layer is removed. 5) The superabsorbent resin is sodium polyacrylate, starch/polyacrylate graft copolymer, acrylic acid/vinyl alcohol copolymer, modified polyethylene oxide, polyvinyl alcohol/maleate ester copolymer, 2. The surface treatment method according to claim 1, wherein the superabsorbent resin is selected from isobutylene/maleic anhydride copolymer, polyacrylic acid resin, and polyethylene oxide resin. 6) The surface treatment method according to claim 1, wherein the object to be treated is a metal, a ceramic such as glass, or a synthetic resin. 7) The metal plate is coated with a treatment liquid mainly composed of a corrosive agent, a superabsorbent resin, and water, or is immersed in the same treatment liquid, dried, and the excess treatment liquid layer is removed. A planar printing plate obtained by forming a photosensitive layer on a plate. 8) Form an image of water-repellent ink on the surface of the object, and then
A surface treatment method characterized by applying an aqueous solution containing a corrosive and a super absorbent resin to perform a partial surface roughening treatment.