Envalior is launching UDea EcoPaXX Q20HTC60, a new high-performance thermoplastic unidirectional (UD) tape for high-pressure all-thermoplastic hydrogen pressure vessels. This continuous fiber-reinforced tape can be used to wrap and mechanically reinforce polyamide liners, allowing tank systems to withstand high pressure loads that occur during tank filling and storage.

UDea EcoPaXX Q20HTC60, Envalior’s new high-performance thermoplastic UD tape for high-pressure all-thermoplastic hydrogen pressure vessels.

UDea EcoPaXX grade is based on polyamide 4.10 and reinforced with 60% by weight of UD continuous carbon fibers. The alternative carbon fibers used in the composite increase the tape’s tensile strength in fiber direction by more than 15% to around 2.2 gigapascals (GPa) compared to equivalent materials reinforced with lower strength carbon fibers.

The new tape completes Envalior’s broad portfolio of thermoplastic materials for the manufacture of hydrogen pressure vessels, which also includes impact-modified polyamide 6 compounds from the Durethan and Akulon brands for blow molding, injection molding, and rotational molding of tank liners.

Strong material bonding

One method to apply the thermoplastic tape is via laser assisted tape placement. This can be done using the start-stop principle, reinforcing the liner only in those areas that are essential to withstand the high pressure. Non-load-bearing carbon fibers can be removed from the composite structure, which cannot be done with the incumbent wet-winding thermoset processing method. This results in weight and cost savings of up to 20%.

Applying a polyamide 4.10 based tape to a liner made from a polyamide 6 compound causes the laser-generated melts of both polyamides to form a melt-melt contact at the interface, creating a monolithic structure with a strong material bonding.

"Therefore, the liner is not able to deform independently from the composite structure when exposed to mechanical or thermal loads, which results in less risk of buckling and allows for easier cleaning and maintenance of the pressure vessels in service life," explained Giacomo Perfetti, Sales & Business Development Manager for UDea.

More sustainable

Thermoplastsic based composite material is sustainable. Polyamide 4.10 is partly bio-based and thermoplastic composite is also easy to recycle, in contrast to thermosetting epoxy systems used for pressure vessel winding.

Also, wrapping the liner with the tape does not require any curing or handling of thermoset chemicals for which special occupational safety measures and cleaning protocols are required.

Envalior offers all the materials needed to manufacture tank systems made entirely of thermoplastic materials, which makes recycling of tanks much easier.