Prodn. of flash-free FRP mouldings - by heating glass cloth and thermoplastic melt, placing in vertical flash mould, and feeding cold carbon di:oxide around male tool while pressing

FRP mouldings are produced by heating one or more layers of fabric material to 150 - 300 deg.C placing together with a thermoplastic melt, pressing at 1.1 - 500 bar pressure in a vertical flash mould and cooling. Whilst the material is being pressed, a liquid or gaseous coolant is fed into the mould round the flash gap. The male press tool has a sealing ring in the female tool and bores allow coolant to be fed through the male to a series of circumferential outlets. A glass cloth coated with polyproplene melt is heated by infra-red to 200 deg.C and placed in the mould; this material has a 25 wt.% fibre content. The mould is not heated. The male tool is then closed and the material is pressed at 5 bar. For 4 secs. while this pressure is built up 200 cm3 of CO2 at -50deg.C is fed into the gap between male and female tools. The pressure is maintained for 2 mins. For the procedure a variety of thermoplastics can be used; they can contain various additives. Various textile materials are suitable. ADVANTAGE - Eliminates the formation of flash and hence cuts out trimming operations and their related costs. (Dwg.0/2)