Flexible Multi-Layer Packaging with Oriented LCP Barrier Layer, 1998 Polymers, Laminations & Coatings Conference Proceedings

Liquid crystal polymers (LCPs) have been coextruded with polyester (PET) and polyethylene thermoplastic layers to make high barrier films which are competitive in raw material costs with other high barrier packaging films. The LCP based multilayer films have several advantages over alternative films including: fewer layers, since the LCP layer can meet both water vapor and oxygen barrier needs, high and low temperature capability (minus 200°F to over 400°F), excellent chemical resistance which allows direct contact with many liquids, and very good strength and stiffness. LCPs have also been blended with PET and used in monolayer films where the LCP concentration is 10 to 30 percent, resulting in favorable performance to cost ratio compared to monolayer barriers such as PEN. Applications include flexible pouches for retorted shelf stable food packaging, collapsible liners for drums and containers, flexible moisture barriers for insulation, liners for cryogenic tanks, and protective barrier films used in sensors. The paper will describe the processing of multilayer LCP thermoplastic films, along with processing of 100 percent LCP film. Experimental work with multilayer LCP-PET coextrusion will be explained and applications in the high barrier packaging industry will be discussed.