Foamable polyvinylidene fluoride and methods

Claim 1

A foamable polyvinylidene fluoride material suitable for forming foamed electrical wire insulation having a dielectic constant of less than about 5.0, consisting essentially of a substantially homogeneous mixture of (a) a polymer selected from the group of polymers consisting essentially of a homopolymer of polyvinylidene fluoride, copolymers or terpolymers containing a major portion of vinylidene fluoride with at least one copolymerizable monomer selected from the group consisting essentially of hexafluoropropylene, trifluoroethylene, chlorotrifluoroethylene and tetrafluoroethylene and mixtures of the homopolymer, copolymer, and terpolymer; (b) 0 05 to 5.0 percent by weight of the polymer of (a) of a nucleating agent of discreet, insoluble particles whose average size is less than about 5 microns length in the longest dimension; (c) 0.05 to 5.0 percent by weight of the polymer of (a) of a blowing agent having an activation temperture that is above the melting point of said polymer but below the decomposition temperature of said polymer; and (d) 0.05 to 5.0 percent by weight of the polymer of (a) of a dispersing aid selected from the group of dispersing aids consisting essentially of dialkyl phthalate, dibutoxyethyl phthalate, diisononyl phthalate, ditridecyl phthalate, dicyclohexyl phthalate, diphenyl alkyl adipate, methyl phthalyl ethyl glycolate, and diethylene glycol monobutyl ether.