Molding High Durometer Flexible Plates from a Thermosetting Liquid Polymer System.

Some of the problems involved in making a flexible duplicate letterpress plate which will reproduce satisfactorily in printing, the fine detail in the mold are reviewed and discussed. Two new plates of this type based on a thermosetting liquid polymer system are described and compared with a 70 durometer rubber plate as to tendency of fine detail to distort and mushroom with increasing impression. Results show that one of these plates is capable of quite acceptable reproduction of light half-tone shades and at the same time remains sufficiently flexible to be mounted easily on tympans and handled like a flexographic plate.