Producing compression molded fibre reinforced plastics panel.

摘要

A method for producing a compression molded fiber reinforced plastics panel (10) comprising a plate (100) having integrally molded reinforcing ribs (202, 206, 210, 220) on one of its surfaces which method comprises:
A. providing a mold with heated first and second mold members shaped to conform to the desired configuration for said panel;
B. introducing plastics molding compound between said members, said molding compound comprising a plurality of superimposed layers (1-4) each containing plastics molding composition of substantially equal paste viscosity in the range of 20-30 million centipoise at 25 DEG C, a first part of said layers comprising a thermosetting resin and relatively short fibers and the other part of said layers comprising thermosetting resin and relatively long chopped fibers, the weight ratio of said first to said other parts being not higher than about 1:2; the weight ratio of said relatively short to said relatively long chopped fibers being not higher than about 1:2; and the ratio of average fiber length of relatively long to said relatively short fibers being at least 3:1;
C. closing said mold members upon said molding compound at a pressure in a first pressure range sufficient to cause flow of said molding compound between said mold members;
D. maintaining said pressure in the first pressure range for a period of at least 15 seconds;
E. reducing the pressure to a pressure in a second pressure range and permitting said molding compound to cure at least substantially at a pressure in said second pressure range;
F. parting said mold members; and
G. removing said panel from between said mold members.