Tremendous interest has been generated in the application of polyurea RIM for exterior body panels. Since polyureas are more thermally stable than polyurethanes, they offer distortion-free parts including even on-line painted body panels.
New technology has been developed recently to improve the reaction profile of polyurea formulations, enabling the molding of large surface area panels on conventional RIM injection units.
The dimensional stability required for exterior body panels (especially the low CLTE) requires reinforcement with glass or mineral fillers. However, new applications have been somewhat restricted by limitations of the reinforcement technology: excessive orientation effect of properties; low impact strength; or distinctness-of-image (DOI) values lower than painted sheet metal.
This paper summarizes the improvements provided by Bayflex 150 DOI (high DOI polyurea), a new multiple-release polyurea RRIM formulation which incorporates novel reinforcement technology. This composite offers an extremely isotropic property profile, improved impact performance, and distinctness-of-image values of coated parts essentially identical to those of painted sheet metal.