Patent ID: 7300703
Filing Date: 2007-11-27
Classification: B29C,B29K,B32B,C08G,C08J,C08L,H01L,H05K,Y02E,Y02P,Y10S,Y10T

Abstract:
1. A process of manufacture of a composite film comprising a substrate layer and on a surface thereof a barrier layer, wherein said substrate layer is a heat-stabilised, heat-set, oriented film comprising poly(ethylene naphthalate) having a shrinkage at 30 mins at 230° C. of less than 1%, said process comprising the steps of: (i) forming a layer comprising poly(ethylene naphthalate); (ii) stretching the layer in at least one direction; (iii) heat-setting under dimensional restraint at a tension in the range of about 19 to about 75 kg/m of film width at a temperature above the glass transition temperature of the polyester but below the melting temperature thereof; (iv) heat-stabilising under a tension of less than 5 kg/m of film width, and at a temperature above the glass transition temperature of the polyester but below the melting temperature thereof; and (v) disposing on a surface of the substrate a barrier layer.