Industrial Automation Magazine India

Polyamide 6 is a cost-effective monolayer solution for fuel tanks

Published on : Thursday 23-04-2020

Double-shell, welded motorcycle tank Powerful barrier effect against gasoline High design flexibility, easy to recycle and Good welding properties.

Cologne, April 2020 – Materials for motorcycle tanks need to meet stringent requirements. This means, for example, that only very small amounts of fuel should be able to diffuse through the tank walls. The materials need to demonstrate a high level of tenacity and ductility, particularly in the event of a crash, offer high design flexibility for complex tank geometries, and should be cost-effective to process. BMW Motorrad’s models F 900 R and F 900 XR have been able to meet all of these requirements thanks to a single material. The tanks in both machines are made from Durethan BC550Z 900116 DUSXBL by LANXESS. The unreinforced and impact-modified polyamide 6 is injection-moulded into two half-shells, which are then welded to form a tank by means of hot plate welding. “Our material comfortably meets the stringent requirements of the United States Environmental Protection Agency (EPA) with regard to permeation. Since it is very easy to process in injection moulding, even complex geometries can be produced cost-efficiently. And when it comes to impact loading, this extremely tough material really shows its strengths,” explains Dr Klaus Küsters, Business Development Manager Blow Molding in the High Performance Materials (HPM) business unit of LANXESS. The tanks are a joint development of BMW Motorrad and Röchling Automotive Italia S.r.l. in collaboration with LANXESS.

The monolayer solution with polyamide 6 has several advantages over previously used tank materials. The design flexibility and the integration potential of this material are significantly higher in comparison to metals, such as sheet steel and aluminium. There is also no need for costly forming, stamping, and joining steps. Corrosion is also not a factor when polymers are used. Durethan BC550Z 900116 DUSXBL has significantly lower fuel permeation compared to other polymers, such as high density polyethylene (HDPE). Although fluorination can further reduce permeation in HDPE tanks, it is advantageous to avoid this additional manufacturing step due to the costs involved and the chemically aggressive fluorine.

The monolayer solution with polyamide 6 is significantly less expensive than multi-layer systems that contain a highly polar layer, usually made of ethylene vinyl alcohol copolymers, as a permeation barrier.

If the wall thickness is designed accordingly, the permeation values of the monolayer solution are several times lower than the limit of 1.5 grams per square meter of inner surface per day (g/m2?d) as required by the EPA (Environmental Protection Agency) in EPA 40 CFR.

Another special feature of this material solution is its very high impact resistance.