| 摘要 |
In a process for producing free-flowing polytetrafluoroethylen (P.T.F.E.) moulding powder an aqueous slurry of granular P.T.F.E. powder having a specific surface area of from 1 to 4 sq.m./g. is subjected to the action of blades at not more than 30 DEG C. until the slurry has an average weight particle size of 200 to 700 microns, the powder is separated, washed with agitation in water at 40 to 70 DEG C., and then dried. "Average weight particle size" is defined in terms of a modification of ASTM D-1457-56T. A suitable starting slurry can be obtained by the process of Specification 574,688. A bladed commercial comminuting machine suitable for use in the process is described. Specifications 572,265 and 638,328 also are referred to. |
