PRODUCTION OF SYNTHETIC RESIN MOLDING

摘要

PURPOSE:To control changes in the thickness of trough-shaped parts of a molding to the minimum possible extent by presetting the preheating temperature of a forming sheet at a value not less than the cure reaction initiating temperature of a thermosetting synthetic resin liquid. CONSTITUTION:Molding dues 11 are heated to 90 deg.C, a pressure forming box 12 is raised and a forming sheet 6 preheated to 80 deg.C is arranged between the molding dies 11 with its flexible lower film 72 downward. The pressure box 12 is then lowered and pressure air is supplied to press the forming sheet 6 and air is also expelled from a recess part 13 through sucking holes 14. Due to the pressing action from the pressure forming box 12 and owing to the reduction of the pressure in the recess part 13, the forming sheet 6 is deformed downwards and into a nearly V-shaped cross section and its lower end part is pressed against the bottom surface S2 of the recess part 13. When the forming sheet 6 preheated to at least cure reaction initiating temperature of synthetic resin liquid is pressed against a molding face S, the synthetic resin liquid which has already started its cure reaction is further heated by the molding die 11 and its viscosity is increased in a short time, thereby controlling the entry of the synthetic resin liquid into the trough-shaped corners (c) of the molding face S.