Development of Tough, Low Mass Class A SMC

摘要

Increasing competition from lightweight metals has necessitated the development of lower density, Class A SMC formulations to mold composite parts for automotive, truck and recreational vehicles. Customer requirements of little or no loss of cosmetic and mechanical properties required major modification to most formulation components. Component evaluations included the use of toughened polyester thermosets, blended systems of low profile additives, and the impact of rubber polymeric tougheners, reactive monomer additives, and a novel filler package. Improvements in 'toughness' and low profiling efficiency have allowed the preparation of parts, without glass microspheres, that have a density of 1.5 to 1.6 g/cc, excellent cosmetics and mechanical properties, and improved resistance to painting defects. This paper reports on the laboratory development work and field trials leading to the present tough, low mass (TLM), Class A SMC molding formulation.