Cleveland, Ohio - New ethanol-based fuels in use in the US and other regions are posing a challenge for the materials used in storage tanks and fuel dispensing systems.
Lubrizol Corp. has developed two Estane thermoplastic polyurethane (TPU) grades with improved chemical resistance, specifically for use with E85 motor fuel.
E85 is fuel which contains 85 percent ethanol and 15 percent gasoline: Lubrizol says this makes it "a popular fuel choice due to the reduced emissions and the national push for energy independence."
"While most of the E85 effort is currently on commercial fuel storage, a trend is developing to include military alternative fuel applications as well," commented Ralf Huther, Estane TPU marketing manager, in a 5 March announcement from Lubrizol.
As well as being suitable for use with E85, Estane X-1351 and Estane X-1352 TPUs can also be used with jet fuel, diesel and biodiesel.
"They also provide improved hydrolysis resistance, which is important since some of the fuels contain water, and there can be environmental exposure as well," said Huther. Estane TPUs provide superior flexibility and strength through a broad range of temperatures, including sub-zero, as well as excellent adhesion to common fabrics and various substrates.
The X-1351 grade is a 95 Shore A hard ester-based TPU with up to 80-percent reduction in E85 permeability compared to a similar ester grade. The X-1352 type is a 62 Shore D ester-based TPU which offers up to 95-percent reduction in E85 permeability.
TPUs such as Estane are "ideal for applications such as collapsible fuel tanks, fuel hoses, vapour recovery components, secondary containment, floating tanks, tank liners and sensors," Lubrizol said. This results from TPU's superior abrasion, wear, tear and puncture resistance compared to conventional materials such as rubber or PVC materials.
PIC Military fuel storage tanks, where new TPU grades offer lower permeability to ethanol-based fuels.