Nonimaged waterless lithographic master with a curable silicone elastomer and a cured ink releasable silicone layer

Abstract

A process for preparing a waterless lithographic printing master is provided. A suitable substrate, which is preferably ink accepting is first coated with a curable silicone which is curable at low or elevated temperature and a second different curable silicone deposited on said first silicone which can be preferentially cured at a lower temperature without curing the first silicone and which second silicone contains, in addition to its own catalyst, an amount of high temperature curing catalyst sufficient to cure the underlying silicone. The surface silicone is then preferentially cured at least on its surface to render it nontacky, but not the underlying silicone. A particulate image pattern is deposited on the surface cured silicone which pattern comprises a material which selectively inactivates the curing catalyst and combines with the catalyst to degrade the cured silicone below said image pattern at elevated temperature, the underlying silicone cured in the nonimaged areas to an elastomeric ink releasable condition, as well as the surface layer to the extent that it was not previously rendered ink releasing, and the particulate image pattern and preferably the degraded and uncured silicones removed beneath said pattern to reveal the ink accepting substrate in image configuration.

Dependencies are inferred from the claim text.