Light-sensitive printing plate for waterless planographic printing with inner and outer layer of silicone rubber wherein outer layer has higher degree of crosslinking than inner layer

• US 4,937,169 A
• Filed: 09/15/1988
• Issued: 06/26/1990
• Est. Priority Date: 09/18/1987
• Status: Expired due to Fees

• Current Assignee: Hoechst Aktiengesellschaft (Sanofi )
• Original Assignee: Hoechst Aktiengesellschaft (Sanofi )
• Inventors: Schlosser, Hans-Joachim
• Primary Examiner(s): Bowers, Jr., Charles L.
• Application Number:
  US07/244,479
• Time in Patent Office: 649 Days
• Field of Search: 430/162, 430/166, 430/167, 430/271, 430/272, 430/303
• US Class Current: 430/162
• CPC Class Codes: G03F 7/0752 in non photosensitive layers or as additives, e.g. for dry lithography

Abstract

A light-sensitive printing plate for waterless planographic printing is disclosed comprising a support, a superimposed light-sensitive layer, an outer, ink-repellent silicone rubber layer, and an inner, ink-repellent silicone layer between the light-sensitive layer and the outer silicone rubber layer, the outer silicone rubber layer having a higher degree of crosslinking than the inner layer. The printing plate is less sensitive to scratching and, at the same time, shows good developability and image resolution.

Claims

1. A light-sensitive printing plate for waterless planographic printing, comprising:

a support;

a superimposed light-sensitive layer selected from the group consisting of a light sensitive layer which becomes soluble in developer upon exposure to light and a light-hardenable layer which becomes insoluble in a developer upon exposure to light; and

2. A light-sensitive printing plate as claimed in claim 1, wherein the condensation-crosslinked multicomponent silicone elastomer comprises the reaction product of a combination of

(a) a diorganopolysiloxane having terminal Si-OH groups,

(b) an organopolysiloxane containing hydrogen atoms bonded to silicon and having no amino groups,

(c) an amino-substituted organo-silicon compound and

(d) a catalytically acting organo-tin compound.

3. A light-sensitive printing plate as claimed in claim 1, wherein the addition-crosslinked multicomponent silicone elastomer comprises the reaction product of a combination of

(a) a diorganopolysiloxane having terminal Si-vinyl groups,

(b) an organopolysiloxane having at least three hydrogen atoms bonded to silicon,

(c) a platinum complex of a vinyl siloxane and

(c) an agent which retards the addition of hydrogen atoms bonded to silicon to aliphatic multiple bonds at room temperature.

4. A light-sensitive printing plate as claimed in claim 1, wherein the outer silicone rubber layer has a layer thickness ranging from about 0.2 to 10 μ

m.

5. A light-sensitive printing plate as claimed in claim 1, wherein the inner silicone rubber layer has a layer thickness ranging from about 0.1 to 10 μ

m.

6. A light-sensitive printing plate as claimed in claim 1, wherein the light-sensitive layer comprises a diazonium salt polycondensation product.

7. A light-sensitive printing plate as claimed in claim 1, wherein the outer silicone rubber layer comprises a condensation-crosslinked multi-component silicone elastomer, and the inner silicone rubber layer comprises an addition-crosslinked multi-component silicone elastomer.

8. A light-sensitive printing plate as claimed in claim 7, wherein the light-sensitive layer comprises a light-hardenable layer.

9. A light-sensitive printing plate as claimed in claim 7, wherein the light-sensitive layer comprises a diazonium salt polycondensation product.

10. A light-sensitive printing plate as claimed in claim 1, wherein the outer silicone rubber layer comprises a condensation-crosslinked multi-component silicone elastomer, and the inner silicone rubber layer comprises a crosslinked single-component silicone elastomer.

11. A light-sensitive printing plate as claimed in claim 10, wherein the light-sensitive layer comprises a diazonium salt polycondensation product.