Nucleated nylon/PTFE compositions

Claim 1

Polycaproamide/polytetrafluoroethylene composition extrudable to form flexible tubing having low friction and high wear resistance, when serving as a sleeve bearing for steel wire, wherein: (1) the polycaproamide has molecular weight corresponding to Formic Acid Relative Viscosity, by ASTM Test Method D-789-72, in the range from about 30 to about 150; (2) the polytetrafluoroethylene is a particulate, waxy product, having melt index by ASTM Test Method D 1238-73 at 360° C. and 2160 gm. load, in the range from 0.1 to 100 gm. per 10 minutes; and the PTFE particles have average diameter not over 50 microns; (3) the composition includes as nucleating agent 0.01% to 10%, by weight of the total composition, of at least one water-insoluble organic salt or inorganic salt or oxide, capable of promoting alpha crystallization of polycaproamide and having average particle diameter not over 40 microns; the polytetrafluoroethylene constitutes from 5% to 25% by weight of the total composition; and the polycaproamide constitutes essentially the balance of the composition; and (4) the additives are dispersed throughout the polycaproamide, such that the particles and agglomerates have average diameter not exceeding 50 microns; and such that the melt index of the composition, by ASTM Test Method D 1238-73 at 235° C. and 1000 gm. load, is at least 2 units below that of the polycaproamide without said polytetrafluoroethylene.