| 摘要 |
<p>1291867 Polyester film of improved flexibility MINNESOTA MINING & MFG CO 22 Sept 1969 [23 Sept 1968] 46637/69 Heading B5B [Also in Divisions C3 and B8] A biaxially oriented film formed from a visually uniform blend of a major proportion of polyethylene terephthalate and at least “%, preferably 2 to 30%, by weight of a solid, fusible heat-stable (at the fusion temperature of polyethylene terephthalate) compound comprising an olefin polymer preferably polyethylene or polytetramethylene oxide or a blend of polyolefin with nylon, said olefin polymer, or polytetramethylene oxide or blend of polyolefin with nylon being distributed throughout the film in the form of discrete microscopic particles, preferably microplatelets. The film, which has a tensile strength of at least 15,000 p.s.i. at 25‹ C., a good resistance to cracking when flexed, and a softening temperature of at least 220‹ C., may be prepared by intimately blending the polymers, forming a film, such as by melt extrusion, and biaxially orienting the film for example at a draw ratio of 3 : 1 longitudinally and transversely. The film may be laminated with low density polyolefin and the laminate formed into heatsealable packaging bags.</p> |
