| 摘要 |
Oriented polyolefin film, contg. (A) polyolefin base layer(s) and (B) a sealable outer layer of polyolefin (B1) contg. hollow particles consisting mainly of a polymer (B2) which is incompatible with (B1). Also claimed is (i) a process for the prodn. of this film, by compressing and heating the film-forming polymers in an extruder, extruding the melt(s) through a sheet die at a temp. below the Tg of polymer (B2), drawing off the film on roller(s) and then orienting and opt. heat-fixing and surface-treating; (ii) a mixt. of polyolefin and less than 2 (pref. 0.001-2) wt% hollow particles of (B2); (iii) a laminate of the above multilayer film with paper, cardboard or other thermoplastic film. Pref. from 70 to less than 100 wt% of layer (B) consists of a 2-10C olefin polymer, and layer (A) contains at least 60 (pref. 70-99) wt% polyolefin. Layer (B) contains not more than 5 (pref. 0.001-3) wt% particles (B2), pref. in the form of spherical particles with no concave surface segments, or with 1-20 concave segments, in which case the enclosed vol. tends to zero and the particles consist mainly of polymer skin. At least 90% of the particles (B2) have a max. dia. of 0.2-20 (pref. 1-15) microns. Particles (B2) consist of syndiotactic polystyrene, polyphenylene sulphide, polyether-ketone, polyamide, polyethylene or polybutylene terephthalate, polyaramid, polyimide, halogenated polymer, amorphous or partly crystalline cyclo-olefin polymer, or metathesis polymer. Layer (A) may contain pigments, pref. TiO2, and/or vacuole- initiating fillers. The film has a density of not more than 1.7 (pref. 0.4-1.5) g/cm<3>, and the outer layers have a thickness of 0.2-2 microns. |
