Abstract
The use of polyurethane reaction injection molding (PU-RIM) to produce au tomotive fascia is well known. More recently, this technology has been used to produce body panels. To allow PU-RIM to maintain competitiveness with other plastic processes internal mold release (IMR) technology was highly desirable. Recent developments by the Dow Chemical Company have resulted in the first commercialization of PU-RIM IMR technology for the production of automotive fascia. Further developments have extended the use of IMR chemistry to the production of body panels.
But the conversion of conventional PU-RIM fascia production to IMR contain ing technology was not done easily. The same surface energy phenomenon which results in multiple release of the substrate from the tooling caused the primer to display unacceptable wetout characteristics when applied to the con ventionally washed fascia. Secondly, the IMR in use today is heat migratory and thus the sequence of postcure prior to washing was mandatory for the suc cessful cleaning of fascia prior to the application of primer.
This paper describes the development of wash chemistries to overcome the initial unacceptable primer wetout which was inhibiting the conversion of PU- RIM molders to this IMR technology. Several aqueous wash chemistries and heat migration studies will be discussed. Adhesion testing of the successful primed fascia will also be presented.
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