METALLIC EXTENSIBLE POLYPROPYLENE FILM WITH IMPROVED METALLIC BREAKAGE RESISTANCE

摘要

PURPOSE: To obtain a multilayered polypropylene film enhanced in metal fracture resistance by simultaneously extruding a polypropylene homopolymer core layer and a skin layer with a specific thickness comprising an ethylene/propylene copolymer or the like to form the skin layer on one surface of the core layer. CONSTITUTION: A multilayered film structure is obtained by simultaneously extruding a polypropylene homopolymer core layer and a skin layer with a thickness of about 2 gauge or less comprising an ethylene/propylene copolymer or an ethylene/propylene/butene-1(EPB) terpolymer to form the skin layer on one surface of the core layer. Next, a film support is biaxially stretched and the skin layer is subjected to flame or corona discharge treatment and metal coating is applied to the treated skin layer. The polypropylene homopolymer used in the core layer of the film has a polymeric structure comprising 80-100% isotactic unit and containing a series of asymmetric atoms arranged on a polymer chain in the same form at a regular interval. The EP copolymer of the skin layer consists of about 0.5-10 wt.% ethylene and about 99.5-90 wt.% propylene.