| 摘要 |
PURPOSE:To obtain the dampening waterless photosensitive planographic printing plate which is excellent in scumming resistance, printing resistance and tone reproducibility by using a silicone rubber layer formed by using a specific crosslinking agent. CONSTITUTION:The silicone rubber layer is formed by crosslinking alkenyl polysiloxane having at least two pieces of alkenyl groups directly bonded to a silicon atom in one molecule and the hydrodiene polysiloxane of formula I by an addition reaction. In the formula I, R<1>, R<2> are a hydrogen atom or methyl group; R<3>, R<4> are a methyl group, vinyl group or phenyl group; m+n=5 to 30, m:n=3:1 to 1:3. The degree of hardening of the silicone rubber layer is adequately controlled in this way and the dampening waterless photosensitive planographic printing plate which is excellent in the scumming resistance, printing resistance and tone reproducibility is obtd. |
