High temperature resistant composite used for rear muffler cover of BMW i8
Local reinforcement of thermoplastic compression molding compound Resistant to low temperatures & very rigid at high temperatures Significant increase in stiffness and impact resistance As reported earlier, companies increasingly are using Tepex performance composites from Lanxess subsidiary Bond-Laminates to improve the mechanical strength of components made of fiber-reinforced thermoplastic compression molding compounds (see also Plastic brake pedal for colume production and Automotive infotainment mount weighs nearly 50% less than steel counterpart). The latest example is a cover on the rear muffler of the BMW i8.
Polypropylene compression molding compound reinforced with long glass fiber rovings
It is fabricated in a direct long fiber thermoplastic (DLFT) process from a polypropylene compression molding compound reinforced with long glass fiber rovings. An insert made of Tepex dynalite 104-RG601 is used as the surface layer. Stiffness at high temperatures ensures that the cover undergoes no deformation or failure in the hot environment of the rear muffler. In addition, the composite improves the strength and impact resistance of the component in freezing temperatures.
Significant increase in stiffness and impact resistance
The Tepex insert is 0.5 millimeters thick and made of a polypropylene matrix, incorporating 47 percent by volume continuous glass fiber rovings as a single-layer fabric. Due to this insert, the stiffness of the cover increases by a factor of four at room temperature and a factor of six at the operating temperature of the rear muffler, according to the company. Impact resistance benefits as well. In penetration tests to DIN EN ISO 6603-2, the Tepex dynalite formulation used proved to be eight to nine times more impact resistant at room temperature than a DLFT compression molding compound based on polypropylene.
Great application potential with GMT and LWRT materials
The material can also be used for locally reinforcing components made of other thermoplastic compression molding compounds and forming materials. For example, the mechanical properties of Tepex-reinforced DLFT polypropylene materials are comparable with glass-mat-reinforced and glass-fabric-reinforced thermoplastic systems (GMT and GMTex) based on polypropylene. The combination of Tepex with the DLFT process opens up considerable savings potential, for instance in the fabrication of underbody components. Polypropylene-based, low-weight reinforced thermoplastics (LWRT), which are used to manufacture underbody panels due to their high sound absorption, can also be stiffened with Tepex surface layers. Using a single-layer Tepex component preserves the acoustic effect. Picture: With its stiffness at high temperatures, Tepex ensures that the cover undergoes no deformation or failure in the hot environment of the rear muffler (source: Lanxess)