Process for high modulus polymeric materials
AssigneeNational Research Development Corporation
InventorsGiancarlo Capaccio, Francis S. Smith, Ian M. Ward
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Abstract
A process for the production of a high modulus filament of polyethylene which comprises heating high density polyethylene to a temperature above its melting point, extruding the polymer to form a filament, subjecting the filament immediately after extrusion to a tension under such conditions that the filament is shaped without substantial orientation of its molecules, cooling the filament at a rate of cooling in excess of 15.degree. C. per minute, and drawing the filament to a high draw ratio. This is a continuation of application Ser. No. 860,999, filed Dec. 15, 1977, abandoned, which is a continuation of Ser. No. 553,656, Feb. 27, 1975, now abandoned.
Claims10
A process for the production of a high modulus filament of polyethylene having 50,000<Mw<200,000 and 5,000<Mn<25,000 which comprises heating high density polyethylene to a temperature above its melting point, extruding the polymer to form a filament, subjecting the filament immediately after extrusion to a tension while maintaining the filament at an elevated temperature such that the filament is shaped without substantial orientation of its molecules, cooling the filament at a rate of cooling in excess of 15.degree. C. per minute to yield a spun filament having a birefringence of not more than 3.times.10.sup.-3 and a density of not more than 0.96 gm. per cc., and drawing the filament to a draw ratio of at least 20.
Dependencies are inferred from the claim text.