New polyamides for blow moulding

Polyamide will replace HDPE due to stricter fuel tank emission rules

Advances in materials promise good performance in automotive and other mobile applications.

DSM’s low permeation material for small fuel tanks

Akulon Fuel Lock FL40-HP from Netherlands-based DSM Engineering Plastics is a polyamide 6-based material designed for blow moulding into offroad fuel tanks. These are used for engines powering handheld and ground-supported lawn and garden equipment, as well as recreational, professional landscaping and marine applications.

Tests on the material are said to yield hydrocarbon permeation rates less than 5% of the maximum value of 2.0g/m²/day allowed for these applications by Californian state regulations. This represents a reduction of evaporative emissions from small-engine fuel tanks of more than 99% as compared with high-density polyethylene (HDPE).

Akulon FL40-HP achieves this low permeation level without the use of additives or post-moulding processes such as fluorination, says DSM, which claims that “risks of non-conformance due to improper or inadequate processing are almost completely eliminated. Tanks molded from this grade also exhibit excellent cold impact resistance, even in temperatures as low as -40°C.”

The company notes that due to more stringent regulation of maximum levels of hydrocarbon permeation by the US Environmental Protection Agency (EPA), high-density polyethylene (HDPE), the material which used to be most commonly used for fuel tanks, can no longer be used in its current form. Akulon Fuel Lock can be processed with conventional blow- or injection moulding equipment, using existing HDPE tooling. All scrap material can be reused in the moulding process, with virtually no degradation of physical or mechanical properties.

Rhodia addresses hot automotive environments

To meet what it sees as an increasing demand for automotive turbo technology solutions, Rhodia Engineering Plastics, a member of the Solvay group, offers the Technyl heat performance range of polyamide 6.6 grades. These are specifically designed for both blow- and injection-moulding parts for turbocharged engines. Technyl B2 is a new blow moulding grade for complex tubular parts capable of resisting temperatures up to 210°C.

Following on from its success in diesel engines, European manufacturers now consider turbocharging a critical technology for powertrain development using downsized petrol engines, says Rhodia. The company offers the Technyl heat performance range as suitable for turbo intercoolers and air duct systems, expecting to broaden the uptake of polyamide in underbonnet applications.

Manuel Rossi, innovation to market leader for Rhodia Engineering Plastics, says: “In addition to its high temperature resistance, the new generation of Technyl grades for turbo applications offers excellent processability and cost-competitiveness. This undoubtedly makes it the best technical and economic compromise for Tier 1s to meet OEMs’ growing challenges in terms of higher temperatures and tougher thermal environments.”

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