| abstract |
A laser-engravable flexographic printing element comprising an elastomeric, relief-forming, laser-engravable, thermally and/or photochemically crosslinkable layer comprising, as binder, at least 5% by weight of syndiotactic 1,2- polybutadiene having a content of 1,2-linked butadiene units of from 80 to 100%, a degree of crystallinity of from 5 to 30% and a mean molecular weight of from 20,000 to 300,000 g/mol on a flexible, dimensionally stable support. n The elastomeric, relief-forming, laser-engravable layer preferably comprises: n (a) from 50 to 99.9% by weight of one or more binders as component A consisting of n (a1) from 5 to 100% by weight of syndiotactic 1,2-polybutadiene having a content of 1,2-linked butadiene units of from 80 to 100%, a degree of crystallinity of from 5 to 30% and a mean molecular weight of from 20,000 to 300,000 g/mol as component A1, and n (a 2 ) from 0 to 95% by weight of further binders as component A2, n (b) from 0.1 to 30% by weight of crosslinking, oligomeric plasticizers which contain reactive groups in the main chain and/or reactive pendant and/or terminal groups as component B, n (c) from 0 to 25% by weight of ethylenically unsaturated monomers as component C, n (d) from 0 to 10% by weight of photoinitiators and/or thermally decomposable initiators as component D, n (e) from 0 to 20% by weight of absorbers for laser radiation as component E, and n (f) from 0 to 30% by weight of further conventional additives as component F. |