| 摘要 |
955,266. Polystyrene filamentary materials. UNION CARBIDE CORPORATION. Sept. 9, 1960 [Oct. 14, 1959], No. 31056/60. Addition to 940,621. Heading B5B. Elongated structures (e.g. fibres, monofilaments and ribbons) of isotactic polystyrene are longitudinally stretched firstly at 115‹-130‹ C. to effect a stretch of 300-650%, and secondly at 125‹-150‹ C. to effect a total longitudinal stretch of at least 750%. Preferably, first stage stretching is effected at 125‹ C. and second stage stretching at 135‹ C. Conventional heating and stretching means may be used. As shown, a 50-filament isotactic polystrene row is fed from storage drums 4 over guides 6, 8 to a constant-speed feed roll assembly 10, and thence through a heating zone 12 to a godet roll assembly 14, the speed of which in relation to that of 10 is sufficient to impart the required first stage stretch. The tow then passes through a second heating zone 16 to godet roll assembly 18, the speed of which relative to 14 is such that the required total stretch is obtained, and is wound up on spool assembly 20. Monofilaments may alternatively be extruded, cooled to 115-130‹ C. and fed directly into suitable stretching apparatus. Filamentary material so treated has enhanced tensile strength, reduced elongation and thermal shrinkage and is insoluble in tetrachlorethane.
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