In automotive design, nylon composite sheet hybrid technology is a particularly useful alternative to metals for reducing the weight of structural parts such as front ends, which are subjected to high mechanical loads. At the same time, it can be used to make all-plastic structures significantly lighter. One example of this is the housing for a passenger airbag module. The use of nylon composite sheet cuts the weight of the housing by over 30 percent compared with a mass produced, injection-molded version made of polyamide 6. “The lightweight construction potential of nylon composite sheet hybrid technology can thus also be applied to plastic parts to considerably lower the weight and thus the emissions and fuel consumption of vehicles in the spirit of Green Mobility,” explained Julian Haspel, an expert in hybrid technology at LANXESS' Semi-Crystalline Products business unit. The housing was designed as part of a joint advanced engineering project between LANXESS, Takata-Petri AG of Aschaffenburg, KraussMaffei Technologies GmbH of Munich, Bond-Laminates GmbH of Brilon and Christian Karl Siebenwurst GmbH & Co. KG of Dietfurt.
Wall thicknesses significantly reduced
The airbag housing accommodates the gas generator and the folded airbag. Until now, such components were made mainly of steel, aluminum, or by the injection molding of thermoplastics. In this concept housing for the passenger airbag, the long side walls are made of molded Tepex dynalite 102 RG 600 from Bond-Laminates. This nylon composite sheet of polyamide 6, reinforced with 47 percent continuous glass fibers 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 nylon composite sheet hybrid technology enables the wall thickness of the side walls to be reduced from 3 to 4 mm to 0.5 to 1 mm, resulting in a considerable cost savings.
High strength and stiffness
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 nylon composite sheet,” said Haspel. Nylon composite sheet hybrid technology is generally suitable for all plastic automotive parts where high stiffness and strength need to be combined with low weight. Engine bearings are one example.
HiAnt – precise simulation of all process steps
LANXESS can accurately simulate all process steps in the manufacture of nylon composite sheet hybrid parts – including the highly complex processes involved in forming the nylon composite sheet. “For the airbag housing, we were able to calculate the different local fiber alignments in shaped nylon composite sheets in order to account for their anisotropic behavior at the part design stage,” said Haspel. This expertise is part of the HiAnt brand, in which the Semi-Crystalline Products business unit has pooled the know-how it has developed in materials, design, simulation and process technology to deliver tailored customer service.
Green mobility – a core strategic topic at LANXESS
In this fiscal year, LANXESS is focusing its activities on the core strategic subject of Green Mobility. The aim of the campaign is to focus on innovative technologies and products with which the specialty chemicals group can help to enable resource-saving, environmentally friendly, sustainable mobility, such as lightweight construction concepts for body parts or high-performance rubber for the manufacture of smooth running, fuel-saving Green Tires.
LANXESS (lanxess.com) is a leading specialty chemicals company with sales of EUR 7.1 billion in 2010 and currently around 16,100 employees in 30 countries. The company is at present represented at 47 production sites worldwide. The core business of LANXESS is the development, manufacturing and marketing of plastics, rubber, intermediates and specialty chemicals. LANXESS is a member of the leading sustainable indices Dow Jones Sustainability Index (DJSI) World and FTSE4Good.