Technology for rapid impregnation of fibre bundles with a molten thermoplastic polymer

Composites consisting of long, discontinuous fibres and a thermoplastic pol ymer find increasing application because of the good overall compromise bet ween their mechanical properties, processing possibilities and cost. Pellet s containing a thermoplastic polymer and long fibres allow injection or com pression moulding of high-quality products. The pellets are usually produce d by a pultrusion process. However, pultrusion with thermoplastics suffers from a compromise between optimised impregnation quality and high productio n speed. A high production speed means low cost. In other words, a compromi se between price and quality exists. This paper presents a significantly mo dified process which uses powered rotating spreader pins with a convex coni cal shape. Thus. the physical basis of the compromise between price and qua lity is altered, and a good quality can be obtained at a fibre-bundle linea r speed of about 1 m/s. (C) 2000 Elsevier Science Ltd. All rights reserved.