JPS61230151A - Original plate for waterless lithographic printing - Google Patents

Abstract

PURPOSE:To obtain excellent curability and good scratch resistance by laminating and disposing a specific silicone rubber layer on a photosensitive layer provided on a substrate. CONSTITUTION:The substrate, the photosensitive layer and the silicone rubber layer are laminated and provided in this order. The silicone rubber obtd. by curing the compsn. contg. an organopolysiloxane having a silanol group and silane bonded with four ketoximate groups with a silicon atom or the condensation product of the hydrolysis thereof is used for the above-mentioned silicone rubber layer. The silicone rubber layer which has the four hydrolyzable groups bonded with the same silicon atom as a crosslinking agent has excellent activity, is thoroughly cured and has the good scratch resistance after curing. The waterless lithographic printing plate having the silicone rubber layer which is good in the curability and excellent in the scratch resistance is thus obtd. by the above-mentioned constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a waterless lithographic printing original plate that can be printed without using dampening water.

[Conventional technology]

Many waterless lithographic plates have been proposed so far that can be printed without using dampening water by using a silicone rubber layer as an ink repellent layer, and are widely used because of the feature that there is no need to control the amount of dampening water during printing. It's broken. In particular, a waterless lithographic printing original plate consisting of a substrate, a photosensitive layer, and a silicone rubber layer in this order is effective because of its good single-image reproducibility and ease of plate making.

C - Problems to be Solved by the Invention] Conventional silicone rubber layers of waterless lithographic printing original plates have been made of organopolysiloxanes having silanol groups and hydrolyzable groups such as acetoxy groups and ketoximate groups containing silicon atoms. A reaction with a silicon compound (hereinafter referred to as a crosslinking agent) directly bonded to the silicone rubber layer is superior in terms of stability of adhesion between the silicone rubber layer and the photosensitive layer.

However, the cross-linking agents that have been proposed so far have five or fewer hydrolyzable groups bonded to the same silicon atom, and the activity of the hydrolyzable groups is low, making it difficult to obtain a sufficient cured state. Therefore, even after curing, there was a problem in that cleaning the silicone rubber layer with an organic solvent would easily cause scratches, that is, the scratch resistance would be poor. One solution to this problem is to add known metal salt catalysts such as tin and titanium to the pre-curing composition of the silicone rubber layer, but if the amount of these added increases, the elasticity of the silicone rubber layer is lost. There is a point.

The present invention aims to provide a waterless lithographic printing original plate having a silicone rubber layer with better scratch resistance and curability than conventional ones.

[Means for solving problems]

The present invention provides a waterless lithographic original plate comprising a substrate, a photosensitive layer, and a silicone rubber layer laminated in this order, wherein the silicone rubber layer comprises an organopolysiloxane having a silanol group and four ketoximate groups on a silicon atom. The present invention relates to a waterless lithographic printing original plate having a silane bonded to the silane.

The substrate in the present invention is not particularly limited, but may be any substrate used in known waterless lithographic printing original plates.

Examples include metal plates such as aluminum, iron, and zinc, organic polymer films such as polyester 9, polyamide, and polyolefin, and composites thereof. It is also possible to further coat these sheets for the purpose of preventing halation, etc., and use them as a substrate.

As the photosensitive layer of the present invention, various photosensitive layers used in a waterless planographic printing original plate formed by laminating a known substrate, a photosensitive layer, and a silicone rubber layer can be used. Particularly effective components in the photosensitive layer include:

(1) Unsaturated bonding groups that can be polymerized by exposure as shown in Japanese Patent Publication No. 56-23150 (e.g. acryloxy group)
Those with

(2) Those having a group (for example, cinamylidene group) that can be dimerized by exposure as shown in JP-A No. 60-21050.

(3) Those having a quinonediazide group as shown in JP-A No. 55-59466.

It is.

The thickness of the silicone rubber layer in the present invention is arbitrary, but if it is too thick, the developability will be poor (and if it is too thin, the ink repellency will be poor), so it is preferably 0.5 to 100 microns, more preferably 1 to It is 20 microns.

The silicone rubber layer, which is a feature of the present invention, is a silicone rubber obtained by reacting an organopolysiloxane having a silanol group with a silane in which four ketoximate groups are bonded to a silicon atom or a hydrolyzed condensate thereof,
A desirable composition ratio of the silicone rubber composition before curing is as follows.

(1) 100 parts by weight of organopolysiloxane having silanol groups (2)
Silane in which four ketoximate groups are bonded to a silicon atom or a hydrolyzed condensate thereof 0.1 to 20 parts by weight (more preferably 0.5 to 10 parts by weight) (3) Known crosslinking agent added as necessary or a hydrolyzed condensate thereof 0 to 20 parts by weight (more preferably
(0.1 to 20 parts by weight) The organopolysiloxane of the above-mentioned component (1) has as a main component a structural unit as shown in the following formula.

(In the formula, R4 and R1 are organic groups.) H2R2 is preferably a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms, and moreover, 60 or more groups are methyl groups in the ink. Desirable in terms of repulsion. The structure of organopolysiloxane is
9. It can be in any shape such as linear, 9-branched, or network-like, but it is generally linear, and if the molecular weight is low, the ink repellency will decrease.9.・If it is too high,
1,000 to 1,000, since scratch resistance decreases.
Preferably, it is 000,000. The silanol group may be located either in the main chain or at the end of the main chain, but in terms of the physical properties of the rubber obtained, it is preferable that the silanol group be located at the end of the main chain.For the same reason, the number of silanol groups is 1.5 on average. It is desirable that the number is at least 1.

The above-mentioned constituent component (2), the silane in which four ketoximate groups are bonded to the silicon atom, is defined as formula (II) or formula (I).
It has the structure II).

In formula C, R'', R', R' gi organic group
% @R'IR4 is preferably a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and from the viewpoint of ease of synthesis of raw materials, methyl group, ethyl group, propyl group, butyl group , preferably a phenyl group. Further, R6 is preferably a substituted or unsubstituted divalent hydrocarbon group having 3 to 10 carbon atoms, and more preferably a butylene group, a pentene group, or a hexene group).

for example.

CH.

CH.

An example of these synthesis methods is A.

Singh, A.K., Rai, and R.C.
, Mahrotra, Journal of Chem
ical 5ooiety, $alton Tran
sactions, 19.1911 (1972). Similar effects can also be obtained by using these hydrolyzed condensates.

The above-mentioned component (3) known crosslinking agent refers to a crosslinking agent known as a silicone rubber (1) Typically, linear formula (III), (IV), (V), (VI),
Examples include those represented by (■) or those exposed to hydrolyzed condensates.

x'51 (III) x, 5iR (■) x, s * R2 (V ) (wherein, X is a ketoximate group, acyloxy group, aminooxy group, amino group, alkenyloxy group, alkoxy group, amide group, etc. Degradable group.

R is an organic group in which carbon is bonded to a silicon atom.

m≧2. n≧0. Structural units can be random or blocks).

Although these known crosslinking agents are not essential, their addition is effective in controlling the physical properties of the resulting silicone rubber.

The above silicone rubber composition before curing should have a composition in which the number of hydrolyzable groups such as ketoximate groups in components (2) and (3) is about the same to twice as many as the number of silanol groups in component (1). For example, rubber can be formed by reacting as shown in the following formula.

3 (-8i OH) + X s Si R → (9
5i-0-2,8i R13XH (in the formula, X is a ketoximate group,
.

(3) The composition has a large excess of ketoximate groups.

For example, by bringing the silanol groups into a state where they are extinguished as described below and further supplying water, a rubber can be obtained by repeating the generation of silanol groups and the condensation reaction with hydrolyzable groups.

In this case, components (1) and (2) may be reacted in advance, or components (1) and (3) may be reacted in advance.

It is also effective to add the following components to the silicone rubber composition before curing.

(4) Organopolysiloxane without silanol groups (5) Known adhesion promoters such as silane coupling agents (6) Known curing catalysts such as tin and titanium compounds (7) Filling with silica, calcium carbonate, etc. for reinforcement purposes Agent (8) A non-reactive solvent for the purpose of improving coating properties Due to the component (2) of these silicone rubber compositions, the silicone rubber layer is crosslinked as shown in the following formula in the printing original plate after curing. It has a point structure.

OH The printing original plate described above can be made, for example, by the following method.

First, a composition solution to form a photosensitive layer is applied onto a support using a conventional coater such as a reverse roll coater, an air knife coater, or a Meyer bar coater, or a rotary coater such as a Whaler, followed by drying and drying. After heat curing, if necessary, apply an adhesive layer on the photosensitive layer in the same manner, and after drying, apply the silicone rubber composition on the photosensitive layer or the adhesive layer in the same manner. Usually 60
Heat treatment is performed at a temperature of ~130° C. for several minutes to fully cure and form a silicone rubber layer. If necessary, a protective film is laminated onto the silicone rubber layer using a laminator or the like.

The thus obtained waterless lithographic printing original plate is irradiated with actinic rays through the original film, and developed by rubbing with a development pad using a known developer depending on the type of photosensitive layer. The image on the original film is reproduced, and the silicone rubber layer remains and the ink does not adhere to the non-image area, and the silicone rubber layer peels off and the photosensitive layer or substrate is exposed and the ink adheres to the image. A waterless lithographic printing plate is obtained, which consists of a portion that will become a copy. Printed matter can then be obtained by installing the printing plate in an offset printing machine and printing without applying dampening water.

〔Example〕

Examples are shown below. In addition, all the blended parts in the examples are parts by weight. Also, in the first sentence, the composition of silicone rubber is described, but unless otherwise specified, this is the 4th grade of coating.
Each composition was mixed 8 hours before, stirred at 60° 0 for 60 minutes, and then stored in a sealed state at room temperature until coating.

Example 1 On a grained aluminum plate.

(1) Ethyl acrylate/methyl methacrylate copolymer 60 parts (2) 4 morphs of glycidyl methacrylate and xylylene diamine 1
Molar addition reaction 40 parts (3) Michler's ketone 5 parts ethyl cellosolve solution was applied.

It was dried at 50° C. to provide a photopolymerizable photosensitive layer with a thickness of 5 nm.

As a silicone rubber composition on the photosensitive layer.

V (4) υ, ω-dihydroxyboridimethysiloxane (number average molecular weight 24,000) 100 parts (5
) Tetrakis(dimethylketoxime)silane

Part 3.

(6) Ethyltriacetoxysilane 5 parts (7)
Dibutyltin diacetate 0.1 part (8)
Exxon Chemical ■ Aliphatic Hydrocarbon 1 Isopar E
When a composition consisting of 400 parts was coated and heat-dried at 100° C. for 1 minute, it was completely cured to a thickness of 2 microns.

On this silicone rubber layer, a 6 micron thick polyethylene terephthalate film ("Lumirror" manufactured by Toshi Co., Ltd.) was laminated to form a printing original plate.

The original positive film was vacuum-adhered onto the obtained printing original plate, and a 2.5-meter film was applied from a distance of 1 m using a metal halide lamp 1 idle fin = 2000 manufactured by Iwasaki Electric Co., Ltd.
Exposure was made for a minute. The film of the exposed printing plate was peeled off, and 95 parts of n-hebutane was added.

When it was immersed in a developer consisting of 5 parts of polypropylene glycol (molecular weight 400) and rubbed with a non-woven fabric "Sofpad" manufactured by Dynic Co., Ltd. for development, only the unexposed silicone rubber layer was peeled off and the photosensitive groups were exposed. On the other hand, the silicone rubber layer in the exposed areas remained, and a printing plate with excellent image reproducibility was obtained.

The silicone rubber layer of the resulting printing plate is coated with “isopar”
When the silicone rubber layer was immersed in E and rubbed 10 times back and forth under a load of 200 g/cs+ using Nonwoven Fabric 1 Hise Gauze manufactured by Mukasei Kogyo (■) for 10 times, no scratches were found in the silicone rubber layer.

Comparative example 1 On the photosensitive layer obtained in the same manner as in Example 1.

(1) α,ω-dihydroxypolydimethylsiloxane (number average molecular weight 24,000) 100 parts (2
) Ethyltriacetoxysilane 8 parts (3)
A silicone rubber composition consisting of 0.1 part of dibutyltin diacetate (4) @ 400 parts of Isopar'E was coated and dried by heating at 100° C. for 1 minute, and it was found to be in an uncured state. When it was heated and dried for 2 minutes under the same conditions, it was completely cured and a silicone rubber layer with a thickness of 2 microns was obtained.

Lumirror 1 was laminated on the obtained silicone rubber layer in the same manner as in Example 1 to form a printing base.

The original printing plate was exposed and developed in the same manner as in Example 1 to obtain a printing plate. When the printing plate was subjected to the same sub-scratch test as in Example 1, the silicone rubber layer had many scratches, and #4 scratch resistance was poor.

Example 2 Toluene of γ-cinnamylidene-β-hydroxy-n-propyl acrylate polymer (number average molecular weight 4,000) on a grained aluminum board.

A methyl isobutyl ketone (1 part 1 weight ratio) solution was applied and dried at 60° C. for 3 minutes to provide a 3 micron thick photodimerizable photosensitive layer.

The same silicone rubber composition as in Example 1 was coated on the photosensitive layer and dried by heating at 100° C. for 1 minute to find that it was completely cured.

A 1-luminor mirror 1 having a thickness of 6 microns was laminated on the obtained silicone rubber layer to obtain a printing original plate. When the original printing plate was exposed and developed in the same manner as in Example 1, a printing plate with excellent image reproducibility was obtained.

When the silicone rubber layer of the printing plate was subjected to the same scratch resistance test as in Example 1, no scratches were found.

Comparative Example 2 The same silicone rubber composition as in Comparative Example 1 was coated on the same photosensitive layer as in Example 2 and dried by heating at 100° C. for 1 minute, but it was found to be in an uncured state. In the same way, those that were heated and dried for 2 minutes were cured.

This was made into a silicone rubber layer.

A 1-luminescent mirror 2 having a thickness of 6 microns was laminated on the obtained silicone rubber layer to prepare a printing original plate.

A printing original plate was exposed in the same manner as in Example 1.

It was developed to obtain a printing plate. When the silicone rubber layer of the printing plate was subjected to a sub-scratch test in the same manner as in Example 1, many scratches were found.

Example 3 A grained aluminum plate was coated with phenol formaldehyde resol resin manufactured by Sumitomo Durres Kusunoki to a thickness of 1 micron, and cured at 200° C. for 3 minutes to obtain a substrate.

On top of this, a tetrahydrofuran solution of a partially esterified product of a phenol formaldehyde novolak resin with a number average degree of polymerization of 4.7 and a naphthoquinone-1°2-diazide-5-sulfonic acid chloride (esterification rate of 49°) was applied,
A photosensitive layer having a thickness of 2 microns was formed by heat treatment at 100° C. for 35 seconds.

on this photosensitive layer.

(1) d,ω-dihydroxypolydimethylsiloxane (
Number average molecular weight 46,000) 100 parts (2)
Tetrakis (methyl ethyl ketoxime) silane
4 parts (3) 0.1 part dibutyltin diacetate (4) 1 part γ-aminopropyltrimethoxysilane (5) A silicone rubber composition consisting of 400 parts of Isopar RtJ was applied and io.

It was heated and dried at .degree. C. for 2 minutes to obtain a completely cured silicone rubber layer with a thickness of 6 microns.

On the obtained silicone rubber layer, a 10 micron thick polypropylene film (manufactured by Toshi Co., Ltd.
) was laminated and used as a printing plate. The original negative film was vacuum-adhered onto the printing original plate, and exposed for 1 minute in the same manner as in Example 1.

Peel off the "Trephan" on the original plate in the exposed area and apply "Isopar" E/ethyl alcohol mixture (weight ratio 75/25)
When the plate was developed by immersing it in water and rubbing it with a soft pad, a printing plate with excellent image reproducibility was obtained in which the silicone rubber layer and photosensitive layer were peeled off in the exposed areas and the silicone rubber layer remained in the non-exposed areas.

The printing plate was subjected to a sub-scratch test in the same manner as in Example 1, but no scratches were found in the silicone rubber layer.

Example 4 A printing original plate was obtained in the same manner as in Example 3, except that the silicone rubber layer had the following composition (the silicone rubber layer was dried by heating at 100°C for 2 minutes). fully cured and 3 microns thick).

(1) α, +4+-dihydroxypolydimethylsiloxane (number average molecular weight 4 (5,000) 100
Part (2) Tetrakis (methyl ethyl ketoxime) silane Part 2 (3) Vinyl tris (methyl ethyl ketoxime) silane
2 parts (4) dibutylstin diacetate), 0.1 part (5) 1 part γ-aminopropyltrimethoxysilane (6) 400 parts of “Isopar” H The obtained printing plate was treated in the same manner as in Example 6. After exposure and development, a printing plate with excellent image reproducibility was obtained.

When the printing plate was subjected to a scratch resistance test in the same manner as in Example 1, no scratches were found in the silicone rubber layer.

Example 5 A mixed solution of liquid A and liquid B shown below (171 weight ratio) was coated on the photosensitive layer of Example 3, and dried by heating at 100°C for 2 minutes to obtain a completely cured thickness. A 3 micron silicone rubber layer was obtained.

Solution A (1) α,ω-dihydroxypolydimethylsiloxane (number average molecular weight 46,000) 100 parts (2
) Tetrakis (methyl ethyl ketoxime) silane
4 parts (3) 0.1 part dibutyltin diacetate (4) 1 part γ-aminopropyltrimethoxysilane (5) 400 parts “isopar-z” Solution B (1) α, ω-dihydroxyboridimethylborisiloxane (number average molecular weight 46,000) 100 parts (2
) Vinyltris(methylethylketoxime)silane 4 parts (3) Dibutyltin diacetate) 0.1 part (4)
γ-Aminopropyltrimethoxysilane 1 part (5) 1 Aituba”E 400 parts
Then, a 10 micron thick "Trephan" was laminated on the silicone rubber layer to obtain a printing original plate.

When the obtained printing original plate was exposed and developed in the same manner as in Example 3, a printing plate having excellent image reproducibility was obtained. When the printing plate was subjected to a sub-scratch test in the same manner as in Example 1, no scratches were found in the silicone rubber layer.

Example 6 On the same photosensitive layer as Example 3.

(1) 100 parts (2
)@isopar"B 400 parts and (3) tetrakis (methyl ethyl ketoxime) silane 1.0 part (4)
Vinyltris(methylethylketoxime)silane
0.5 part (5) γ-
Aminopropyltrimethoxysilane 1 part (6) Toluene 0.5 part (7
) A composition consisting of 0.1 part of dibutyltin diacetate was mixed and coated 10 seconds later.

When heated and dried at 100° C. for 2 minutes, it was completely cured and a silicone rubber layer with a thickness of 2 microns was obtained.

Furthermore, a 10 micron thick "Tre 7 Anne" was laminated on the silicone rubber layer to obtain a printing original plate.

When the obtained printing original plate was exposed and developed in the same manner as in Example 3, a printing plate having excellent image reproducibility was obtained. When the scratch resistance test of the printing plate was conducted in the same manner as in Example 1, no scratches were found in the silicone rubber layer.

Comparative example 3 On the same photosensitive layer as Example 3.

(1) α,ω-dihydroxyboridimethylsiloxy,
San (number average molecular weight 46.000) 100 parts (2) Vinyltris (methyl ethyl ketoxime)
Silane 4 parts (3)
Diptyltin acetate 0.1 part (4)
A silicone rubber composition consisting of 400 parts of γ-aminopropyltrimethoxysilane 1 part (5) 1 Isopar" E was coated and heated at 100°C for 2 minutes and dried, but it was not completely cured.Similarly, After heating and drying at 100°C for 5 minutes, a completely cured silicone rubber layer with a thickness of 3 microns was obtained.Trephan 1 with a thickness of 10 microns was laminated on the silicone rubber layer to prepare a printing original plate.

The obtained printing original plate was exposed in the same manner as in Example 3.

A printing plate was obtained by development. When this printing plate was subjected to the same sub-scratch test as in Example 1, many scratches were found in the silicone rubber layer.

Example 7 A tetrahydrofuran solution having the following composition was applied onto the substrate in Example B at 125°C.

A 2 micron thick photosensitive layer was provided by heat treatment for 35 seconds.

(1) Phenol formaldehyde novolak resin with number average polymerization degree of 4.7 and naphthoquinone-1,2-diazide
Partially esterified product of 5-sulfonic acid chloride (esterification rate: 49 yen) 100 parts (2) 4,4/-
50 parts of diphenylmethane diisocyanate (3) 0.2 parts of diptyltin diacetate on the resulting photosensitive layer.

(4) d,ω-dihydroxypolydimethylsiloxane (
Number average molecular weight 34,000) 100 parts (5) Tetrakis(dimethylketoxime)silane

3 parts (6) Vinyltris(dimethylketoxime)silane 3 parts (
7) Diptyltin diacetate 0.1 part (
8) A silicone rubber composition consisting of 0.2 parts of T-aminopropyltriethoxysilane (9) 400 parts of "Isopar" E was coated, heated and dried at 100°C for 2 minutes, and completely hardened. A silicone rubber layer with a thickness of 3 microns was obtained, and a 10 micron thick layer of 1-Trephan 1 was laminated thereon to obtain a printing original plate.

- The obtained printing original plate was exposed in the same manner as in Example 3.

When developed, a printing plate with excellent image reproducibility was obtained. When the printing plate was subjected to II and A clutch tests in the same manner as in Example 1, no scratches were found in the silicone rubber layer.

Example 8 On the same photosensitive layer as Example 7.

(1) α,ω-dihydroxypolydimethylsiloxane (number average molecular weight! 14,000) 100 parts (
2) 3 parts vinyltris(dimethylketoxime)silane (3) diptyltin acetate (4) 1 isopar''E to a composition prepared 48 hours ago consisting of 400 parts.

(5) Tetrakis (dimethylketoxime silane)
3 parts (6) γ-aminopropyltriethoxysilane 0.
2 parts (7) 3 parts of toluene was added and applied as a silicone rubber composition, and 100
When it was heated and dried at ℃ for 2 minutes, it was completely cured.
A silicone rubber layer with a thickness of 3 microns was obtained, and a 10 micron thick layer of 1 trepan was laminated thereon to obtain a printing original plate.

The obtained printing original plate was exposed in the same manner as in Example 3.

When developed, a printing plate with excellent image reproducibility was obtained. When the printing plate was subjected to a scratch resistance test in the same manner as in Example 1, no scratches were found in the silicone rubber layer.

Comparative example 4 On the photosensitive layer obtained in Example 7.

(1) α,ω-dihydroxypolydimethylsiloxane (number average molecular weight 34,000) 100 parts (2
) Vinyltris(dimethylketoxime)silane
6 parts (3) Dibutyltin diacetate 0.1 part (4) γ-aminopropyltriethoxysilane 0.2 part (5) “Isopar = lit 4
Coating a silicone rubber composition consisting of 100 parts
After heating and drying at ℃ for 2 minutes, curing was insufficient. A completely cured silicone rubber layer was obtained by heating for 5 minutes. On top of that, 1 tre 7 an 1 with a thickness of 10 mm and 9 mm was laminated to form a printing original plate. A printing plate obtained by exposing and developing a printing original plate in the same manner as in Example 3,
When a sub-scratch test was conducted in the same manner as in Example 1, the silicone rubber layer was found to have many scratches.

〔Effect of the invention〕

By using a silicone rubber composition having the characteristics of the present invention, a waterless lithographic printing plate having a silicone rubber layer with good curability and excellent sub-scratch resistance can be obtained.

Claims (1)

[Claims] (1) In a waterless lithographic original plate in which a substrate, a photosensitive layer and a silicone rubber layer are laminated in this order, the silicone rubber layer comprises an organopolysiloxane having a silanol group and four ketoximate groups on a silicon atom. 1. An original plate for waterless lithographic printing, characterized in that it is a silicone rubber obtained by curing a composition containing bound silane or a hydrolyzed condensate thereof.