Lanxess hybrid tech helps make airbag housing 30 percent lighter

Specialty chemicals company Lanxess has announced that its polyamide composite sheet hybrid technology can help reduce the weight of the airbag housing in an airbag module by over 30 percent.

The airbag housing, which accommodates the gas generator and the folded airbag, plays a critical role in an airbag module. Until now, these components were made mainly of steel, aluminium, or by the injection moulding of thermoplastics. Lanxess says its polyamide composite sheet hybrid technology offers a value-added alternative over metals to help reduce the weight of structural parts which are subjected to high mechanical loads. Also, in comparison with polyamide 6, use of polyamide composite sheet cuts the weight of the housing by over 30 percent.

When the airbag is triggered in an accident, the base and walls of the housing must be able to withstand the explosion and the pressure during inflation of the airbag. Although the side walls are so thin, they can withstand the sudden pressure because of the high strength and stiffness of the hybrid polyamide composite sheet. Polyamide composite sheet hybrid technology is generally suitable for all plastic automotive parts where high stiffness and strength are required in combination with low weight (hybrid brake pedal is one such example).

In this concept housing for the passenger airbag, the long side walls are made of moulded Tepex dynalite 102 RG 600 from Bond-Laminates, now a Lanxess subsidiary. This polyamide composite sheet of polyamide 6, reinforced with 47 percent continuous glass fibres by volume, is back-injected and reinforced in certain areas with Durethan DP BKV 240 H2.0, an impact-modified polyamide 6 copolymer from Lanxess. The design using polyamide composite sheet hybrid technology enables the wall thickness of the side walls to be reduced from 3 to 4mm to 0.5 to 1mm, resulting in considerable cost saving.

Lanxess says it can accurately simulate all steps of the process in the manufacture of polyamide composite sheet hybrid parts – including the highly complex processes involved in forming the polyamide composite sheet. For the airbag housing, the company is able to calculate the different local fibre alignments in shaped polyamide composite sheets to account for their anisotropic behaviour at the part design stage.