Glass-Filled PET for Automotive Exterior Components

Two new glass-reinforced-grades of PET said to deliver  superior mechanical properties, appearance, and weather resistance for automotive exterior components are available from Polyplastics Group.  The Renatus 30% glass-filled RH030 and 45% glass-filled RH045 grades reportedly maintain their jet blackness and reduce whitening on the surface of molded articles in outdoor environments, making them ideally suited for applications such as automotive side mirrors and rear wiper arms/blades.

Since PET parts are not painted, weathering degradation can occur over time. The glass filler can start to float and the jet blackness can decrease. Accelerated weather resistance testing demonstrates that Polyplastics’ new Renatus PET materials maintain lower index values than the competition, thus indicating that whitening is being reduced. While plastic resins are made stronger when reinforced with glass fiber, a negative effect on the surface appearance of molded articles is also a negative effect that can occur.

The RH030 and RH045 grades have been shown to produce molded articles with good surface appearance because of their superior mold transferability during molding. Recent company testing shows that when compared to standard grade 30% glass-filled PBT, RH045 PET exhibits higher surface gloss even though it has a large amount of glass fiber added to the formulation. In terms of mechanical performance, PET typically has superior properties compared to PBT. At similar glass loadings, RH030 and RH045 PET grades have higher mechanical properties including greater tensile strength, flexural modulus, and deflection temperature under load compared to PBT grades.