Patent ID: 8361556

Claim:
A method of preparing a flexographic printing plate precursor, comprising: providing a mixture of EPDM rubbers consisting essentially of of a high molecular weight ethylene-propylene-diene terpolymer (EPDM) rubber and a low molecular weight EPDM rubber, adding a peroxide or hydroperoxide vulcanizer and optional components to the mixture of EPDM rubbers, and compounding the resulting mixture in a mixer to form a compounded mixture, wherein the compounded mixture contains no mineral oil plasticizer, calendering the compounded mixture to provide a continuous sheet of an infrared radiation ablatable layer, causing vulcanization in the continuous infrared radiation ablatable layer, and grinding the infrared radiation ablatable layer, wherein the compounded mixture further comprises a carbon black in an amount of from about 1 to about 20 weight %, and one or more inorganic fillers at a weight ratio of carbon black to inorganic filler of from 1:20 to 1:5.