US Patent 7279441 Compacted olefin fibers

A polyolefin plaque is made by hot compaction of an assembly of fibres of the oriented polymer. It has been found to be beneficial to subject the fibres to a prior crosslinking process. Hot compaction is then less temperature-sensitive and produces plaques with excellent hot strength properties. Preferably the fibres have been subjected to prior stages of irradiation and annealing, both in a non-oxidising environment, for example acetylene.