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

摘要

By melt compounding a majority of liquid crystalline polymer (LCP) with a minority of LDPE and a compatibilizer a homogeneous and coextrudable alloy with superior barrier properties is obtained. It is essential for the barrier properties that the LCP is in majority and forms a continuous phase. When coextrusion coating the LCP-alloy on a substrate 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, the barrier properties to all media including water are excellent because there are no significant physical or chemical interactions with the LCP. The oxygen barrier is equivalent to EVOH in dry conditions but does not decrease in wet and hot conditions. The LCP-alloy is therefore especially suitable for liquid packaging and retortable packaging. One semi-commercial grade is available and new grades that can be processed at lower temperatures and used for other applications are under development.