| 摘要 |
1,195,153. Oriented polyethylene terephthalate films. LA CELLOPHANE. 17 June, 1968 [8 Aug., 1967], No. 28784/68. Heading C3R. Into polyethylene terephthalate is incorporated 0À01-5%, by weight of the polyethylene terephthalate, of a thermoplastic polyamide or polypropylene having a melting-point not above that of the polyethylene terephthalate and the mixture extruded to form a film, the film then being oriented biaxially by stretching in two directions. The polyamide may be derived from caprolactam (Nylon 6), from hexamethylene diamine and adipic acid (Nylon 66), from hexamethylene diamine and sebacic acid (Nylon 610), from amino-undecanoic acid (Nylon 11) or amino-dodecanoic acid (Nylon 12), or may be a polyamide mixture. The polymers may be mixed in granular form before extrusion of the film, or polycondensation of the polyethylene terephthalate may be performed in the presence of the other polymer. Biaxially oriented films according to the invention may be used in electrical condensers (film thickness 2À5-25 microns) or as a support for magnetic tape (thickness 20-125 microns, or 5-40 microns if there is a higher orientation in one direction than in the other). |
