| 摘要 |
Thermoplastic synthetic resin film was prepd. by foaming film at lower than thermoplastic temp. range with PVC which is heat unstable resin (K-value is at least 65), followed by stretching 100-200% (at least 25 %) at thermoplastic temp. range and then stretching again 100-200 % (at least 50 %) at heat stress temp. range secondarily. After stretching step, the film was heat treated at heat stress temp. range.
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