| 摘要 |
PURPOSE:The titled film low in water vapor permeability, free of bleed out and excellent in transparency, stretchability, moldability, oil resistance, etc., comprising PP and a specified petroleum resin or terpene resin. CONSTITUTION:A mixture comprising 100pts.wt. PP having an isotacticity index >=93% and an intrinsic viscosity (as measured in tetraline) of 0.8-4dl/g, and 5- 30pts.wt. polar group-free petroleum resin, glass transition temperature >=50 deg.C, based on a cyclopentadiene or higher olefin hydrocarbon (e.g., hydrogenated alicyclic petroleum resin based on a compound of formula I ) or terpene resin free of polar groups such as hydrocarbons (modified compounds) and having the composition of the formula (C5H8)n is molten at a temperature <=240 deg.C, mixed uniformly, and extruded into an unstretched film on an extruder. This film is then oriented uniaxially of multi-axially and heat-treated to obtain a PP film having a glass transition temperature of 10-50 deg.C and a degree of orientation DELTAN of 0.006-0.012, wherein DELTAN is represented by equation II (wherein NMD, NTD, and NZD are the refractive indices along the length, width, and thickness of the film, respectively).
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