Search Results

Polyurea RRIM for automotive fascia offers all the advantages of Polyurethane RRIM, with improvements in processing and productivity. Polyurea also offers a visibly superior product, creating a better looking and more robust fascia for the customer. Polyurea's faster reactivity translates into improvements in green strength for the molder, allowing faster mold cycles and less scrap from tearing at demold. Polyurea's better dimensional stability produces fascia with clean, straight styling lines and less warping due to changes in temperature or humidity. With polyurethane systems, the selection of reinforcing fillers has meant either accepting nonuniform (anisotropic) physical properties with milled glass fibers or sacrificing surface appearance (as measured by DOI) with glass flake. Mica reinforced polyurethane suffers from poor green strength and is somewhat difficult to process.

Since the development of the reaction injection molding (RIM) process in the late 1960's and its application to flexible damage resistant front and rear bumper systems in the mid 1970's, a continual improvement in material performance and process efficiency has been demonstrated. The conversion from glycol extended to amine extended technology in the early 1980's not only provided improved physical properties and productivity but also allowed for the incorporation of reinforcements to improve dimensional stability (RRIM). Incorporation of internal mold release (IMR) technology in the mid 1980's further increased RIM productivity. And now with the introduction of a new generation of polyurea fascia materials, further improvements in quality, productivity and overall economics can be realized. This paper will outline the quality, productivity and economic benefits of these new polyurea systems for automotive fascia applications.

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.