| 摘要 |
<p>1285478 Heat resistant polyester film MINNESOTA MINING & MFG CO 22 Sept 1969 [ 23 Sept 1968] 46636/69 Heading B5B [Also in Division C3] A biaxially oriented film capable of withstanding ageing at 220‹ C. for at least 100 hours is formed from a visually uniform blend of a major proportion of polyethylene terephthalate and a minor proportion of at least “% by weight of a nylon, preferably nylon 6, or a polycarbonate, the minor polymer being distributed throughout the film in the form of discrete microscopic particles, preferably platelets. The polyester may be formed by zinc-antimony or lithiumzinc-antimony catalysis. In the examples the polymers are blended by adding nylon or polycarbonate pellets to the freshly prepared molten polyethylene terephthalate or, especially in the cases when a high proportion of additive polymer is used, by intimately mixing the ground polyethylene terephthalate with additive polymer pellets. The films show flexibility after up to 100 hours at 220‹ C.</p> |
