PET grade with superior weatherability

Polyplastics Group has announced the introduction of two new RENATUS® polyethylene terephthalate (PET) grades which deliver superior mechanical properties, appearance, and weather resistance for automotive exterior components. The launch reaffirms the company’s strong commitment to PET as a key pillar of its extensive resin business portfolio.

The two new glass-reinforced grades, RH030 (30% glass filled) and RH045 (45% glass filled), maintain their jet blackness and reduce whitening on the surface of moulded 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 PET materials maintain lower index values than the competition, thus indicating that whitening is being reduced.

Plastic resins that are reinforced with glass fibre are typically made stronger but glass filler can also have a negative effect on the surface appearance of moulded articles. RENATUS® RH030 and RH045 PET are glass fibre reinforced grades, but they can still produce moulded articles with good surface appearance because of their superior mould transferability during moulding.

Recent company testing shows that when compared to standard grade PBT-GF30, RH045 (PET-GF45) exhibits higher surface gloss even though it has a large amount of glass fibre 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.