LASER-IMAGEABLE FLEXOGRAPHIC PRINTING PRECURSORS AND METHODS OF RELIEF IMAGING

摘要

A method for preparing a flexographic printing precursor is carried out by forming a laser-engraveable composition in a layer. This laser-engraveable composition has one or more EPDM elastomeric rubbers, at least one of which comprises at least 8 weight % polyene recurring units. This laser-engraveable composition of elastomeric rubbers can be quickly crosslinked using sulfur-containing vulcanizing compositions to provide laser-engraveable compositions and layers in the flexographic printing plate precursors that can be laser-engraved to provide relief images for flexographic printing.

主权项

1. A method for preparing the flexographic printing precursor of claim 1, comprising:
forming a laser-engraveable composition into a laser-engraveable layer, the laser-engraveable composition comprising one or more EPDM elastomeric rubbers in an amount of at least 30 weight % and up to and including 80 weight %, based on the total laser-engraveable composition dry weight, the one or more EPDM elastomeric rubbers comprising a first EPDM elastomeric rubber comprising at least 8 weight % and up to and including 15 weight % of polyene recurring units, the first EPDM elastomeric rubber comprising at least 50 weight % and up to and including 100 weight % of the total elastomeric rubber weight,
the laser-engraveable composition further comprising:a) at least 2 phr and up to and including 60 phr of a near-infrared radiation absorber, andb) at least 3 phr and up to and including 20 phr of a sulfur vulcanizing composition comprising a sulfur-containing vulcanizing compound,wherein the laser-engraveable composition is essentially free of peroxides, and the weight ratio of the near-infrared radiation absorber to the vulcanizing composition is from 1:10 to and including 20:1.