Claims
- 1. A planographic printing plate having:
- a hydrophilic substrate;
- a first coating containing a water soluble light reactive diazo resin on said substrate; and
- a second coating containing a photosensitive solvent-soluble diazo-borofluoride salt and an organophilic hydrophobic water insoluble resin over and in intimate contact with said diazo resin, said organophilic hydrophobic water insoluble resin being less than 50% by weight of said second coating;
- said plate being developable by water or aqueous solution whereby areas of the diazo resin unexposed to light and areas of the diazo-borofluoride salt thereover are washed away to define hydrophilic oleophobic non-printing areas, and areas of the diazo resin exposed to light and the diazo-borofluoride salt thereover define hydrophobic oleophilic printing areas.
- 2. The printing plate of claim 1 wherein:
- the amount of said water insoluble resin in said second coating is from 10% to 45% by weight.
- 3. The printing plate of claim 1 wherein:
- said water insoluble resin is selected from the group including polyvinylacetate, copolymers of polyvinylacetate and polyvinyl chloride, and styrene-butadiene copolymers.
- 4. The printing plate of claim 3 wherein:
- said diazo-borofluoride salt is present as the principal constituent in said layer coated over said diazo resin coating.
- 5. The printing plate of claim 1 wherein said diazo resin is stabilized to provide extended storage capability.
- 6. The printing plate of claim 5 wherein said diazo resin is stabilized with a complex of zinc chloride and a photosensitive diazo salt.
- 7. The printing plate of claim 1 wherein said diazo resin is the condensation product of a diazo salt and an aldehyde.
- 8. The printing plate of claim 1 wherein said diazo-borofluoride salt is a p-diazo-2,5-di(lowery alkoxy)-1-(p-tolylmercapto) benzene borofluoride.
- 9. The printing plate of claim 1 wherein said diazo-borofluoride salt is p-diazo-2,5-diethoxy-1-(p-tolylmercapto) benzene borofluoride.
- 10. The printing plate of claim 1 wherein said diazo-borofluoride salt is p-diazo-2,5-diethoxy-1-(p-tolylmercapto) benzene borofluoride; p-diazo-2,5-dimethoxy-1-(p-tolylmercapto) benzene borofluoride; 1-diazo-2,5-diethoxy-4-morpholino benzene borofluoride; 1-diazo-2-chloro-5-methoxy-4-methylaniline borofluoride; and 1-diazo-3-methyl-4-pyrrolidinobenzene borofluoride.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. application Ser. No. 288,043 filed Sept. 11, 1972, now U.S. Pat. No. 3,837,858.
US Referenced Citations (5)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
288043 |
Sep 1972 |
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