Lateral stretching of adhesive film for laminating foil to polyolefin - to ensure uniform interfacial bonding and high peel resistance

摘要

Metal (aluminium) foil is laminated to each face of a freshly extruded polyolefin sheet by use of pressure and an interfacial film which is laterally stretched immediately before application to the underside of the metal foil. The core layer is pref. a polyethylene of density 0.91-0.97 g/cm3, melt index 0.05-100. The adhesive film is made of a blend of 70-99 pts. wt. of a polyolefin graft copolymer contg. 0.0001-3% wt. of maleic anhydride and 1-30 pts. wt. of a jhydrocarbon elastomer, pref. polyisobutylene or an ethylene-propylene rubber. Typically the film is 10-100 mu m thick. The metal foil is of Al 0.01-0.5mm thick. Stretching of the adhesive film results in good uniform interfacial contact and high delamination resistance.