Graphite impregnated polyamide tennis strings

Abstract

For use in a stringed apparatus, such as a tennis racket, a synthetic string having a cross-sectional diameter between about 0.025 and about 0.08 inch and comprising a plurality of fused, entwined filaments which are composed of a polyamide, such as nylon, impregnated with from about 0.05 to about 2.0 weight percent graphite particles having cross-sectional diameters ranging from about 0.1 to about 2.0 microns. To make the string, polyamide is heated to a temperature between about 300.degree. and 550.degree. F., preferably between about 450.degree. and 500.degree. F., mixed with graphite particles present at a concentration sufficient to promote cross-linkage of the polyamide substantially in the absence of cleavage, filtered, nozzle extruded into filaments, cooled, prestressed, and then fused into a string. A string having a cross-sectional diameter between about 0.05 and 0.06 inch exhibits a tensile strength greater than about 60,000 psi, modulus of elasticity less than about 0.3.times.10.sup.6 psi, and an elongation less than about 18.0 percent at the tension of the breaking point.

Dependencies are inferred from the claim text.