JPS6160795B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lithographic printing plate support in which an aluminum sheet serving as a printing surface is bonded to a steel plate. This invention relates to a lithographic printing plate support that has high durability against force, does not rust due to the layer covering both sides of steel, is inexpensive, and does not require interleaving paper.

Conventionally, what has been widely used as a lithographic printing plate is an aluminum plate that has undergone surface treatments such as graining and oxidation, and is coated with various photosensitive substances and dried.The so-called PS plate is then printed through an original film, etc. This is a printing plate obtained by performing plate-making processes such as development, washing with water, and lacquering after exposure. Due to this development process, the undissolved photosensitive layer (that is, remaining on the support) forms an image area and becomes an ink receiving area because it is oil-sensitive. The exposed aluminum surface is hydrophilic, so
It is a well-known fact that it becomes a water receiving area and forms a non-image area. Currently, aluminum plates are generally used as supports for such lithographic printing plates, but due to the need to ensure mechanical strength such as dimensional stability, relatively thick aluminum plates have no choice but to be used. This is the main reason for increasing the cost of producing lithographic printing plates.

As an inexpensive support that eliminates such cost disadvantages, Japanese Patent Application Laid-Open No. 61302/1989 discloses a support made of a non-stainless steel sheet and an aluminum plate bonded together with an adhesive. Showa 53-2104
The publication discloses a support made of a clad material of iron and aluminum.

However, since all of these substrates use iron, iron rust occurs on the cut surfaces after cutting them into individual sizes, and not only do they have poor storage stability, but they also suffer from corrosion during surface treatment or on the printing press. Acid or alkali such as dampening water caused iron rust on the back of the plate, which caused problems in handling, plate-making work, and surface work. In addition, when stacking plates, interleaving sheets such as paper or polyethylene are required to prevent scratches on the surface of the plates, and for efficient production, multiple sheets are stacked to obtain the desired size. When cutting, there were also drawbacks such as the need to insert interleaving paper laminated with polyethylene or the like to prevent the blade from spilling.

The present invention was made with the aim of eliminating such drawbacks, and its gist is that an aluminum sheet is bonded to one side of a steel plate via an adhesive layer, and a protective layer is attached to the other side of the steel plate. at least one of the adhesive layer and the protective layer.
10μ thick made of polymer with melting point below 120℃
This is a support for a photosensitive lithographic printing plate (PS plate), characterized in that the layer has a thickness of 1 to 100 μm.

When the support of the present invention is used, the following advantages can be obtained. In other words, by providing a layer with a low melting point on at least one surface of the steel, the layer protects the cut surface by overhanging or melting and enveloping it during cutting, so iron rust does not occur at the cut end, and this makes it easier to preserve the material. Improves sex. In addition, because a protective layer is provided on the back side, it will not be attacked by acidic or alkaline liquids during the treatment process of the aluminum surface, or developers during the plate-making process, and dampening water during the printing process. Rust on the back of the printing plate due to penetration of water will not stain the plate cylinder. Furthermore,
When PS plates using the support according to the present invention are stacked in multiple layers and cut into layers, the steel protective layer or adhesive layer acts as a lubricant and prevents damage to the photosensitive layer. This makes it easy to perform overlapping cutting, which was difficult in the past, and also eliminates the need for interleaf paper, making manufacturing and plate-making operations extremely smooth. Of course, it goes without saying that it is also possible to wind it into a coil without cutting it in layers.

Next, the structure of the lithographic printing plate support of the present invention is explained as follows.
This will be explained according to the diagram. In FIG. 1, aluminum (including aluminum alloy) 1 is bonded to adhesive layer 2.
It is bonded to a steel plate 3 via a protective layer 4 on the other side of the steel plate 3. At least one of the adhesive layer 2 and the protective layer 4 is made of aluminum 1
Polymers that melt at temperatures below the melting point of acrylonitrile rubber) mixed plastic,
Polypropylene or polystyrene, preferably polyethylene.

In order to overhang and protect the steel section during cutting, at least either the adhesive layer or the protective layer must be made of a polymer with a melting point of 120°C or less, and
It needs to be thicker than μ. The upper limit of the thickness is not particularly limited, but approximately 100μ is appropriate. Preferably, the adhesive layer has the function of overhanging the steel cross section, and in this case the protective layer may be made of a polymer with a relatively high melting point and may have a thickness of 10 μm or less.

The adhesive layer may also be a common adhesive if the protective layer has the function of overhanging the steel section. Typical examples include rubber-based adhesives such as
Butadiene-acrylonitrile rubber, polybutadiene rubber, butyl rubber, polyurethane rubber and silicone rubber; thermoplastic adhesives such as acetyl cellulose, methyl cellulose, polyester, polystyrene, polyvinyl alcohol, polyvinyl chloride and vinyl acetate-ethylene copolymers; thermosetting adhesives , for example polyester, polyisocyanate, polyurethane, urea-formaldehyde resin, epoxy resin, furan resin, phenol formaldehyde resin, silicone resin.

Further, it is preferable that the aluminum in No. 1 has a thickness of 10 to 100 μm. If it is less than 10μ, it is difficult to grain or anodize the aluminum surface;
When it becomes thicker than 100μ, it can be used alone as a support for a PS plate, and it loses its characteristics as a composite material.

Further, the steel plate No. 3 preferably has a thickness of 50 to 200 μm to prevent overhang during cutting. Particularly preferably, it is 80 to 170μ.

This will be explained below using examples.

Example 1 A steel plate with a width of 300 m/m and a thickness of 120 μm that was degreased at 70°C with a 5% aqueous solution of trisodium phosphate was transported at a speed of 4 m/min, and a steel plate with a width of 300 m that was degreased with a degreasing aqueous solution similar to the above was transported at a speed of 4 m/min. /m, 10μ thick aluminum and plastic (polyisobutylene 30
-40% paraffin, 30-40% paraffin, remaining polyethylene) and thermocompression bonded at 150°C. Adhesive layer thickness is 30
It was μ. Adhesive Polybond AY651A (20 g of liquid A, 3 g of liquid C) from Sanyo Chemical Industries, Ltd. was applied to the back side of the steel plate.
A mixed solution of 138 g of ethyl acetate) was applied at 50 ml/m ² , and a protective layer of polyethylene with a width of 300 m/m and a thickness of 10 μm was bonded and dried with hot air. Then, using pumice stone as an abrasive, the aluminum surface was brushed to an average center depth of around 0.6μ, and the liquid temperature was 43mm.
It was passed through a sodium aluminate bath at ℃. The amount of aluminum etched at this time was 3 g/m ² . After being washed in an aqueous tank and dilute sulfuric acid, it passed through a continuous anodizing tank. In the anodizing bath, an oxide film of approximately 2.4 g/m ² was formed using an electrolyte containing 20% sulfuric acid as a main component at a bath temperature of 30°C. After passing through a water washing tank and drying with hot air at 60°C, a photosensitive liquid having the following composition was applied to provide a photosensitive layer.

Ester compound of Γnaphthoquinone-1,2-diazido-5-sulfonyl chloride and pyrrozalol acetone resin 0.50g Γcresol novolak resin 1.00g Γtetrahydrophthalic anhydride 0.125g ΓOil Blue #603 (Orient Chemical Industry Co., Ltd.)
0.01g Γethylene dichloride 10g Γ2-methoxyethyl acetate 10g The coating solution is applied by dip coating at approximately 50ml/ ^m2 and dried by passing through a drying zone with a temperature gradient of 40 to 100℃. Weight approx. 2.5g/
A uniform photosensitive layer of m ² was formed. The strip-shaped aluminum plate on which the photosensitive layer was formed was then cut with a shear cutter manufactured by Toyo Hamono. The planographic printing plate thus obtained was satisfactory, with the adhesive layer of plastic completely surrounding the cultivated surface of the steel plate.

A positive transparent film original was placed on the photosensitive surface of the photosensitive lithographic printing plate thus obtained, set in a vacuum printer, and exposed for about 1 minute using a carbon arc lamp at a distance of about 80 cm. This was developed with a 7-fold diluted aqueous solution of developer DP-3 manufactured by Fuji Photo Film Co., Ltd., washed with water, dried, and then applied to an offset printer to obtain a large number of prints with excellent images. There is no chance of rust forming on the back side or cross section of the plate after printing, and there is no risk of staining the plate cylinder of the printing press.
It didn't damage the blanket either.

Example 2 In the same manner as in Example 1, the strip-shaped aluminum plate on which the obtained photosensitive layer was formed was cut using the Goebel method manufactured by Toyo Hamono Co., Ltd., and then 30 sheets with a size of 254 m/m x 391 m/m were cut using the Goebel method manufactured by Toyo Hamono Co., Ltd. I cut them in layers using the shear cutter method. These cutting surfaces were able to be cut smoothly because the adhesive layer of plastic wrapped around the steel section, and the adhesive layer of plastic and the protective layer of polyethylene acted as lubricants. Moreover, since there is no interleaving paper, it is easy to stack and align the plates before cutting, and since there is a protective layer on the back side, it is efficient without damaging other plates.

Comparative example Same as Example 1, degreased width 300m/m, thickness
A 120 μ steel plate was conveyed at a speed of 4 m/min, and aluminum having a width of 300 m/m and a thickness of 10 μ, which had been degreased in the same manner as in Example 1, was laminated with Polybond AY651A of Example 1, bonded, and dried with hot air. . The same surface treatment and photosensitive layer coating as in Example 1 were carried out, and the strip-shaped aluminum plate on which the photosensitive layer was formed was cut using the cable method and shear cutter method manufactured by Toyo Hamono. This was subjected to plate making in the same manner as in Example 1, and printed on a large number of sheets using an offset printing machine. As a result, the dampening water causes rust on the back of the printing plate and the plate cylinder, creating depressions in the blanket, causing rust to form on the edges of the printing plate, and the rust sinking into the blanket, forcing the blanket to be replaced. Ta.

Furthermore, when these printing plates were placed one on top of the other in an environment of 35℃ and 75% for three days, rust appeared on the cultivated surface.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of the lithographic printing plate support of the present invention.

Claims (1)

[Claims] 1 An aluminum sheet is bonded to one side of a steel plate via an adhesive layer, and the other side of the steel plate has a protective layer, and at least one of the adhesive layer and the protective layer is made of a polymer with a melting point of 120°C or less. 1. A support for a photosensitive lithographic printing plate (PS plate), which is a layer having a thickness of 10μ to 100μ.