Multi-layer rotationally molded low permeation vessels and method for manufacture thereof

摘要

A multiple walled enclosure with low permeation properties and rugged impact resistance useful as a fuel tank or chemical container. The enclosure is made by rotomolding a first charge of thermosetting polymer into an outer layer, then rotomolding a charge of EVOH or other low permeation thermoplastic into a second layer, then rotomolding a second charge of thermosetting polymer into a third layer so that the low permeation thermoplastic layer is fully enclosed by layers of thermoset polymer. The preferred thermosetting polymer is crosslinkable polyethylene and the preferred low permeation thermoplastic is EVOH.

主权项

1. A vessel comprising
a rotomolded seamless hollow tank having a seamless wall of at least two layers, the wall comprising: a rotomolded seamless outer layer comprising cured crosslinked polyethylene, the outer layer having an internal surface, a rotomolded seamless barrier layer comprising low permeation thermoplastic polymer, the barrier layer adhered to the internal surface of the outer layer, the low permeation thermoplastic polymer comprising ethylene-vinyl alcohol copolymer, the ethylene-vinyl alcohol copolymer having a melt flow index greater than 4.2 g/10 minutes at 190 degrees C with a load of 2160 g, the barrier layer being homogenous on the internal surface of the outer layer.