Abstract: The present invention relates to preparing extruded article by flowing heat plastified stream of extrudable resinous thermoplastic material through an extrusion orifice. In the invention crosslinking additives are introduced and mixed to the surface portion of the stream of extrudable resinous thermoplastic material before the extrusion step. After the extrusion step the crosslinking of the surface portion of the extruded article provided with the crosslinking additives is initiated by special initiation means.

Abstract: The invention relates to method in a process for preparing extruded articles by flowing heat plastified stream of extrudable resinous thermoplastic material through an extrusion orifice. The invention relates further to an extrusion process and an apparatus. In the invention the stream can be separated into a central core stream and at least one boundary stream on the outside of the core stream. Modifying additives are added to the boundary streams while maintaining physical separation of the core and boundary streams. The streams are recombined prior expelling the material out of the extrusion orifice, said boundary streams being applied as a relatively thin surface layer having altered properties between the core layer and the surfaces of the extrusion orifice. The additives can alternatively be added directly to the surface portion of the material stream without any physical separation step.

Abstract: The invention relates to a concentrated, non-agglomerating, soluble and compatible drag reducing agent composition. It contains (a) from 1 to 60% of a polymer, e.g. non-crystalline and ultrahigh molecular weight poly-&agr;-olefin, capable of reducing drag, and (b) from 40 to 99% of a natural fat or oil, e.g. linseed or rapeseed oil, based on the comined weight of (a) and (b). Preferably, it also contains (c) from 0.1 to 50% of a dispersion stabilising agent, e.g. a fatty acid soap, based on the combined weight of (a), (b) and (c).

Abstract: The invention relates to a homo- or copolymer of vinyl chloride. The polymer contains 0.01-50% of an oligomer of a C.sub.4 -C.sub.20 .alpha.-olefin or of an internal olefin or of their mixtures.