Imperial Chemical Industries Limited

National Research Development Corporation

Francis S Smith

Ian MacMillan Ward

Giancarlo Capaccio

Nigel W Hayman

Jack Gould

Bruce M McIntosh

Scott Davidson

A monofilament or multifilament sports racket string, of a thermoplastic aromatic polyetherketone and preferably polyetheretherketone, such string preferably having an elongation not exceeding 5% when a tensile stress of at least 100 Newtons/mm.sup.2 is applied along the axis of the string and preferably having a dynamic stiffness, measured at a mean stress of 175 Newtons/mm.sup.2, of not greater than 1.150 times the dynamic stiffness measured at a mean tensile stress of 80 Newtons/mm.sup.2.

Sports racket strings of a synthetic thermoplastic polymeric material

A process for forming a continuous filament yarn from a melt-spinnable synthetic linear polymer and novel yarns of polyethylene terephthalate and yarns of polyhexamethylene adipamide produced by the process, the process comprising extruding the molten polymer through a shaped orifice to form a molten filamentary material, passing the molten filamentary material through a solidification zone, passing the solidified filamentary material through a conditioning zone provided with a gaseous atmosphere at a temperature above the glass transition temperature of the material and below its melting temperature, withdrawing the resulting filamentary yarn from the conditioning zone and winding up such yarn, characterized in that the gaseous atmosphere in the conditioning zone is compressed steam at an absolute pressure in excess of 5 psig and preferably, in the case of a yarn of polyethylene terephthalate, between 50 and 156 psig and preferably, in the case of a yarn of polyhexamethylene adipamide, between 14 and 70 psig.

Process for forming a continuous filament yarn from a melt spinnable

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.

Process for the continuous production of high modulus filament of

Process for high modulus polymeric materials

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Harrogate, United Kingdom

Francis S Smith