JPS5855932A - Posttreatment of lithographic plate requiring no dampening water - Google Patents

Abstract

PURPOSE:To obtain a print having a sufficient ink film thickness, by forming a nonadhesive material layer on all the lithographic plate requiring no dampening water using a silicone rubber layer as a nonimage part, and removing only the nonadhesive material layer on image lines to leave deep recesses. CONSTITUTION:A soln. contg. a linear organopolysiloxane having the formula (R is 1-10C alkyl, phenyl, vinyl, and preferably, >=60% of it is methyl) as a main component and various cross-linking agents, and capable of cross-linking and hardening is coated on all the surface of a lithographic plate requiring no dampening water using a silicone rubber as a nonimage part in 1-10mum dry thickness, dried, and heat-treated at about 120 deg.C for 3min. The plate is softly rubbed with absorbent cotton soaked with a solvent to remove the silicone rubber layer only on the image lines, thus permitting the silicone rubber layer on the nonimage part to be strongly adhered, durable deep recesses to be formed, and a print having sufficient ink film thickness to be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a post-processing method for a lithographic printing plate that does not require dampening water and uses a silicone rubber layer as a non-image area, and particularly relates to a method for post-processing a planographic printing plate that does not require dampening water, and in particular, it relates to a method for post-processing a lithographic printing plate that does not require dampening water and has a silicone rubber layer as a non-image area. The present invention relates to a method for post-processing a lithographic printing plate that does not require dampening water.

Examples of planographic printing plates that do not require dampening water and have a silicone rubber layer lined on a substrate as a non-image area include (A) JP-A-50-50102, JP-A-55-59466, and JP-B-Sho 46-16044. As shown in No. 1, an image-forming material layer (photosensitive layer) is provided on the substrate.

Those on which a silicone layer is provided (7 silicone upper layer type), Japanese Patent Publication No. 44-23042, Special Publication No. 47-23
No. 61, JP-A-49-82402, JP-A-50-16
No. 305, etc., in which an image forming substance layer (photosensitive layer) is provided on a silicone rubber layer backed by a substrate (silicone underlayer type).

(C) JP-A-49-68803, JP-A-49-3
No. 9200, etc., in which the silicone rubber layer backed on the substrate itself is photosensitive and participates in one image formation (single-layer silicone type) have been proposed.

Among these printing plates, (A) silicone upper layer type and (C
) is a so-called flat intaglio printing plate in which the image area is concave to the silicone layer in the non-image area, and when printing is performed using this, it is transferred to the printing material such as paper. It is believed that the ink film thickness corresponds to the depth of the recesses in the printing plate.

On the other hand, the silicone underlayer type printing plate (B) is a so-called planar relief plate in which the image area is convex with respect to the silicone rubber in the non-image area, and the film thickness of the ink transferred to paper or the like is small.

Using these printing plates, it is effective to increase the thickness of the ink layer, the photosensitive layer, and the depth of the recesses, but in that case it is difficult to obtain a satisfactory image. There was a problem.

The inventors of the present invention have conducted extensive studies to improve these problems, and as a result, have arrived at the present invention.

That is, the present invention.

In a planographic printing plate that does not require dampening water and has a silicone rubber layer lined on the substrate as a non-image area, after a non-adhesive material layer is provided on the printing plate, the non-adhesive substance layer on one image area is The present invention relates to a method for post-processing a lithographic printing plate that does not require dampening water and is characterized by removing only a material layer.

As the non-adhesive substance of the US invention, room temperature curing type or low temperature curing type silicone rubber is suitable, but high temperature curing type silicone rubber, fluorine compounds, etc. can also be used, or several types of these can be mixed. It may also be used.

These/recone rubbers are based on linear organopolysiloxanes having the following repeating units:

(Here, R is an alkyl group having 1 to 10 carbon atoms, a phenyl group, or a vinyl group, and preferably 60 or more of them are methyl groups.) Such linear organic polysiloxanes can be used with various crosslinking agents. are added, each three-dimensionally cross-linked,
It can be cured into rubber. These silicone rubbers come in one-component and two-component types, and are classified as follows depending on their curing mechanism.

One-component type 1. Condensation reaction type - (1) Deacetic acid type (2) Deoxime type (3) Dealcoholization type (4) Deamine type (5) Deamidation type 2 Addition reaction type (1) Vinyl addition reaction type (2) Peroxide type Two-component type 1. Condensation reaction type (1) Dealcoholization type - (2) Deoxyamine type (3) Dehydrogenation type (1) Vinyl addition reaction type (9) These curing reactions usually require various catalysts, Metal compounds etc. are added.

'As a substrate for the lithographic printing plate that does not require dampening water of the present invention.

The thickness is about 10μ to 2mm, preferably about 50μ to 4mm.
Suitable materials include 00μ paper, plastic films or sheets, elastic sheets such as rubber, metal plates such as aluminum, and those with various surface treatments.
A cylindrical substrate may also be used.

The silicone rubber layer used in the lithographic printing plate that does not require dampening water of the present invention is about 05 to 100 μm, preferably about 05 to 10 μm.
The main component is a linear organopolysiloxane with a molecular weight of several thousand to several dozen blades, having a thickness of μ and having repeating units of the order of 2. n is an integer of 1 or more, and R is the number of carbon atoms. 1~
10 alkyl, alkenyl or phenyl groups.

A crosslinking agent is usually added to this linear organic polysiloxane. Common crosslinking agents used in so-called room temperature (low temperature) curing silicone rubber include acetoxysilane, ketooxime silane, alkoxyrane, aminosilane, and amidosilane. When combined with certain types, they are respectively deacetate type, oxime type, alcohol deal type, and amine parent type. It becomes a deamidated silicone rubber.

Moreover, these may be silicone rubber layers imparted with photosensitivity.

Configuration 1 of the printing plate of the present invention As an image forming method, the following is an example.

Examples include the following:

(1) An image-forming material layer is provided on a silicone rubber layer backed with an adhesive layer or the like on a substrate. This is subjected to imagewise exposure, and by utilizing the change in solubility, the 1 image forming 1'1 material layer of 41 image areas is developed and removed to expose the silicone rubber layer. As the image-forming substance, a known photosensitive substance such as a photocurable type or a photodegradable type is used.

(2) A silicone rubber layer backed by a substrate via an image-forming substance layer or the like. An image is obtained by subjecting this to image exposure and removing the silicone rubber layer in one image area by development, or by simultaneously developing and removing the image-forming material layer in the image area and the silicone rubber layer thereon.

As the image-forming substance, a known photosensitive substance such as a photocurable type or a photodegradable type is used.

(3) A silicone rubber layer having image-forming properties is provided on a substrate.

7J-Ngono Layer Iyuni', 1. : An image stand or set up using the r-Shasei method.

etc.

A layer of 11 adhesive 1'1 was applied to the printing plate surface of the dampening water printing plate prepared by the method described above.
The force θ that causes l', for example, the non-viscous γ1 object 4j
A method of applying the solution or dispersion of j directly to the plate surface and drying it, or a method of transferring a non-adhesive material layer provided on a carrier film to the plate surface, and heating according to 2. method etc. can be used.

The carrier film used here has a thickness of approximately 5 μm.
~2 mm, preferably about 9μ to 100μ polyethylene, polypropylene, polyvinyl chloride'.

Polyvinylidene chloride, polyvinyl alcohol, polyethylene terephthalate, carbonate, rophane, ABS.

A plastic film such as polystyrene or nylon is suitable, but a metal plate 1 paper 9 synthetic paper or the like may also be used.

Furthermore, as a method for forming a silicone rubber layer on a carrier film together with a non-adhesive material layer, an uncured silicone rubber solution is coated with a coater.

Krachia Roll Coater, Reno (- Thrall Coater,
Using a continuous coater such as a slit or gui coater,
It may be applied uniformly onto the film and heated at a required temperature for a required period of time to cause a curing reaction to form a non-adhesive material layer.

In the so-called flat intaglio printing plates having the configurations (2) and (3) above, the depth of the recesses in the image area is about 1 μ to about 10 μ.
If the depth is deeper than this, a printing plate faithful to the original picture cannot be obtained.9 However, by the method of the present invention, a non-adhesive material layer of about 0.57-50μ, preferably about 1 to about 10μ, is provided on the plate surface for one stroke. By removing only the non-adhesive material layer on the line area, a printing plate with deep recesses in one image area can be obtained.

In addition, in the so-called plano-relief-type planographic printing plates that do not require dampening water (1) and (4), the non-adhesive material layer is about 0.5 to 50μ, preferably about 1 to 50μ, at least the height of the raised portions. 10μ
A printing plate having four deep parts can be obtained by removing only the non-adhesive material layer similarly provided on the image area while leaving all or part of one image area.

The non-adhesive material layer of the present invention contains a known adhesion improver for the purpose of improving the adhesion with the silicone rubber layer which is the non-image area of the lithographic printing plate that does not require dampening water.

A silicone primer, a 7-run coupling agent, etc. may be added, and a non-adhesive material layer may be provided via the adhesion improver as described above.

1 after applying a layer of non-adhesive material according to the method of the invention.
As a method for removing the non-adhesive material layer on the image area, there is a method of lightly rubbing the plate surface using a developer if necessary. The developer used at this time is mainly a hydrocarbon solvent containing polar solvents such as alcohols and esters as required.

In addition, if a non-adhesive material layer is provided by transfer from a carrier film, it may be removed using a developer in the same way, but the adhesiveness between the non-adhesive material and the silicone rubber layer in the non-image area Also, so-called peel-off development may be performed by utilizing the difference in adhesiveness between the non-adhesive material and the image area.

The present invention will be explained in more detail with reference to the following examples.0 Example 1: A commercially available "lithographic printing plate without dampening water" was subjected to image exposure using a conventional method, and then developed to obtain a lithographic printing plate that did not require dampening water. Ta. Subsequently, a solution of silicone rubber "5H-781" manufactured by Toray Silicone ■ (manufactured by Esso Chemical) was coated on the entire surface of this printing plate so that the dry thickness was 7 microns. This material was heat treated at 120° C. for 6 minutes, and then one plate surface was lightly rubbed with absorbent cotton impregnated with Isopar E to remove only the /Ricoh/rubber layer above the first print area. At this time, the silicone rubber layer on the non-image area was firmly adhered to the printing plate and could not be removed.

The obtained lithographic printing plate that does not require dampening water has recesses with a depth of 7 μ or more as printing areas, and when this plate was used to print with a normal offset printing machine, it had a sufficient ink film thickness. A print was obtained.

A phenol novolak resin, naphthoquinone-1,2-diazide, was applied to a chemically treated aluminum plate manufactured by f1g Yukei Metal Co., Ltd.
The 5-sulfonic acid ester was coated to a thickness of 2.7 μm. Next, a silicone rubber layer having the following composition was provided thereon to a thickness of 2 μm.

(1) Dimethylpolysiloxane 100 parts (molecular weight approx. 30,000, terminal hydroxyl group) (2) Ethyltriacetoxy 7 parts 5 parts (3) γ-Aminopropyltriethoxy/silane 6 parts T! Image exposure is applied to the lithographic printing original plate that does not require dampening water,
The mixture was washed with water and developed with ethanol to obtain a lithographic printing plate that did not require dampening water. This was subjected to the same post-treatment as in Example 1.

A lithographic printing plate which does not require dampening water and has four deep areas as the printing area was obtained.

Using this printed version, Davidson, Dualis 70
When direct printing was performed using a Model 0 printing machine, printed matter with a sufficient ink film thickness was obtained.

Claims (1)

[Claims] (1) In a lithographic printing plate that does not require dampening water and has a silicone rubber layer lined on the substrate as a non-printing area, after a non-adhesive layer is provided on the printing plate, the non-printing area above the 9 printing areas is A post-processing method for a lithographic printing plate that does not require dampening water, characterized by removing only the adhesive layer.