The present invention is directed to a multilayer film having, as its main component, a hydroxy acid polymer with improved gas barrier and optional heat sealability. The oriented film of predominately hydroxy acid polymer having controlled shrink can be produced by melting and coextruding a hydroxy acid polymer with a much thinner layer of an amorphous aromatic copolyester to form a multilayer film that is quench cooled, then biaxially stretched at a process temperature above the glass transition and below the cold crystallization temperature of the hydroxy acid polymer. A heat-setting treatment with a controlled relaxation of the film above the hydroxy acid polymer glass transition temperature and below its melt temperature may be used to control shrinkage. The films thus obtained are vacuum metallized on the aromatic copolyester surface to produce environmentally friendly packaging from predominately renewable resources having improved gas barrier properties.
申请公布号
WO2011041568(A1)
申请公布日期
2011.04.07
申请号
WO2010US50941
申请日期
2010.09.30
申请人
TORAY PLASTICS (AMERICA) INC.;LEE, MARK;YOKOTA, NAO;CHANG, KEUNSUK P.