| 摘要 |
<p>Biaxially oriented multilayer polypropylene (PP) film (I) has base layer(s) (B), interlayer(s) (Z) and outer layer(s) (D), and contains migrating additives in amts. of not more than 0.15 wt.% w.r.t. total wt. of film. Also claimed is a process for the prodn. of (I), by coextruding the melts for the different layers through a sheet die, passing the film over a take-off roller at 10-100 degrees C, stretching with ratios of (5:1)-(9:1) in both longitudinal and transverse directions, heat-fixing, opt. subjecting to corona treatment and winding on a spool. Used as packaging film or laminating film (claimed). Provides biaxially oriented PP film with a constant, opt. low coefft. of friction, and constant antistatic properties, which is suitable for processing on high-speed packaging machines or on laminating drums without blocking or sticking and without evapn. of additive or formation of deposits on rollers etc. The film has good gloss and low haze (if transparent), good printing properties and very low total migration, esp. to foodstuffs.</p> |
