THE USE OF SURFACE-TREATED REINFORCEMENT MATERIAL FOR USE IN EXTRUSION AND INJECTION MOULDING OF THERMOPLASTICS

摘要

Experience has shown that when fiberglass is added to plastic granulate in an extruder, the abrasive action of the fiberglass against the extruder walls and the screw will gradually cause wear damage in the extruder. According to the invention, such wear will be eliminated by the use of fibreglass which has been pre-coated with a suitable thermoplastic material. This is achieved by pre-heating chopped strand fibreglass, having a length of approx. 3 mm to 50-300C. A thermoplastic granulate, with a grain size of between 5-100 mu m is thereafter blended with the hot coated fibreglass under agitation of the components. The thermoplastic granulate is thereby sintered to the surface of the fibreglass forming a coating which later acts as an efficient self-lubricating barrier between the fibreglass and the metal components in the extruder.