- POM with improved tribological properties closes gap to PBT & PA
- Long glass fibre-reinforced PP-GF-30 replaces PA in engine covers
- UD-GF thermoplastics increase safety in parts
Lightweight materials can reduce vehicle weight while increasing performance and functionality in automotive applications. At the recent 16th Industry Forum in Wolfsburg on 25-26 June 2014, Celanese Corporation presented their newest automotive developments, including POM window lift plates, glass fibre reinforced PP engine covers and oriented UD layers as the problem fixer in door handles.
Window lift plates for the VW Amarok made from POM
Celanese presented a study project for the VW Amarok at the Forum: a window lift plate made from a new, glass fibre-reinforced POM grade. The Hostaform XGC material provides improved mechanical properties in stiffness, strength and impact strength over previous glass fibre Hostaform grades thus closing the gap to performance specification glass fibre-reinforced thermoplastics like polybutylene terephthalate (PBT) and polyamide (PA). The improved mechanical properties are demonstrated over a wide range of temperatures and under continuous load. The new POM grade also has improved tribological properties which is an advantage especially in applications with mechanical moving parts. Hostaform XGC requires glass fibre contents of only 10 to 25 percent, depending on the application, while achieving stiffness and strength comparable to 20 or 30 percent glass fibre-reinforced PBT, according to the company. The most important applications are levers, wheels, grippers, catches and gear casings.
Engine cover made from Celstran LFT for TSI engines
TSI stands for Turbocharged Stratified Injection and is the brand name for the engine technology of the Volkswagen Group. A direct injection petrol engine is fitted with a turbocharger or two different chargers. The first TSI engine was a twin charged 1.4-l engine in 2005. Weber Dillenburg constructed an engine cover for the TSI models, still as a project study, using long glass fibre-reinforced Celstran from Celanese. The long glass fibre-reinforced thermoplastic Celstran LFT (PP-GF-30) withstands continuous operating temperatures of 120 degrees Celsius with maximums of up to 140 degrees. The new engine cover from Weber Dillenburg also withstands higher mechanical loads without problem. And the engines run quieter than before because of the acoustic damping characteristics. A weight reduction of up to 20 percent could be achieved by using this material. The cover was originally made from Polyamide 6, but the properties of Celstran LFT prevailed because it has very good impact strength over a wide range of temperatures as well as good resistance to hot engine oil. And using Celstran LFT (PP-GF-30) provides a less expensive engine cover compared to polyamide.
Oriented UD layers as the problem fixer in door handles
No compromises are made regarding safety in automobile construction; thus manufacturers are also increasingly using reinforced components made from continuous fibre-reinforced composites like the door panels (PP and UD-GF) for the Ford Transit Courier. And the requirements are stringent: optimum stiffness and strength are among the specifications.
A team from Celanese and developers from Fompak in Turkey are taking on these challenges. Their aim: to design local reinforcement in the door handle for safety-optimized door panels made from novel materials using thermoplastic tape-laying. Polypropylene (PP) was used for the strengthening inlay in the door handle with unidirectional oriented glass fibres (UD-GF) in the form of so-called UD tapes. The positive conclusion: the lightweight construction meets the high demands and reliability was increased in the demonstration component over the current customary construction made with conventional polypropylene. Due to low tooling costs, component design optimized to load, targeted minimization of material use and the decision in favor of the comparatively inexpensive material combination PP-GF70, an efficient alternative for series production was found.
Inexpensive storage compartment flap for trucks
Another lightweight development is a weight-optimized commercial vehicle storage compartment flap made from thermoplastic UD composites. The tapes made from a thermoplastic matrix are reinforced with unidirectional aligned continuous fibres giving them outstanding mechanical properties: they are light, resilient and can be processed into complex forms. The process was developed in collaboration with the Fraunhofer Institute for Chemical Technology (ICT) and the engineering company EDAG.