Nucleating agent for foam production, used for making the insulating layer for coaxial cable, comprises fluoro-resin powder in which at least half the particles are in the sub-micron range, with no fines

摘要

A cell-forming (nucleating) agent for foam production, comprising fluorinated resin powder (FRP) in which at least 50% of the particles are in the size range 0.1-0.5 microns and not more than 40% have a particle size of not less than 5 microns. Independent claims are also included for: (a) foam consisting of 100 parts by weight (pts. wt.) formable organic polymer and 0.01-1 pt. wt. FRP as above; (b) coaxial cable with an insulating layer of foam as above; (c) a foam production process comprising mixing a formable organic polymer with FRP in the above proportions and then extruding the mixture in presence of a blowing agent in a high- to low-pressure atmosphere; (d) a formable composition containing polymer and FRP as in (a).