A NEW COMPATIBILIZED LCP / LDPE-ALLOY FOR COEXTRUSIONCOATING OF BARRIER PACKAGING MATERIALS

摘要

By melt compounding a majority of liquid crystalline polymer (LCP) with a minorityof LDPE and a compatibilizer a homogeneous and coextrudable alloy with superiorbarrier properties is obtained. It is essential for the barrier properties that the LCP is inmajority and forms a continuous phase. When coextrusion coating the LCP-alloy on asubstrate like paper or board (Substrate / PE / Tie / LCP-alloy / Tie / PE ) a very thin( < 5 μm ) layer of the LCP-alloy can be made. Unlike other barrier polymers, thebarrier properties to all media including water are excellent because there are nosignificant physical or chemical interactions with the LCP. The oxygen barrier isequivalent to EVOH in dry conditions but does not decrease in wet and hotconditions. The LCP-alloy is therefore especially suitable for liquid packaging andretortable packaging. One semi-commercial grade is available and new grades thatcan be processed at lower temperatures and used for other applications are underdevelopment.