| 摘要 |
Thermoplastic web or film is heated at 90 DEG -140 DEG F. for at least 20 hours and then wound into a roll under tension at 80 DEG -140 DEG F. The process is particularly applicable to coated tapes, having a basis of, for example, cellulose acetate, cellulose acetate butyrate, polyethylene, nylon or polyethylene terephthalate. Such a tape, after the initial heating step, to relax the film may be wound directly at 80 DEG -140 DEG F. on to a wide central core, or may be subdivided during winding into a plurality of narrow tapes. The tape may also be subsequently divided and rewound. The reels of tape so obtained are form-retaining and are not subject to wrinkling, loosening or deformation when subsequently subjected to ambient temperatures of, e.g. 50 DEG -140 DEG F. In an example, a typewriter tape intermediate, comprising a film of cellulose acetate butyrate coated with a dispersion of segment in petroleum wax, is heated at 100 DEG F. for 24 hours. The relaxed tape is wound and subdivided into small rolls at a tension of 150 grams per lineal inch width and at 90 DEG F. Conventional coating, winding and heating apparatus are used. Following the initial heating step, the relaxed tape may be stored indefinitely before the winding (conversion) step. |
