Abstract: A preparation process in which PTFE coarse particles are finely pulverized into particles in wet state, thus enabling the finely pulverized particles to be washed as they are and an amount of impurities to be decreased efficiently and after the washing, agglomeration granulation is carried out, thus enabling PTFE molding powder to be obtained in the reduced number of steps; a preparation process of a polytetrafluoroethylene molding powder, characterized in that polytetrafluoroethylene coarse particles obtained by suspension polymerization of tetrafluoroethylene are finely pulverized, in wet state, into an average particle size particularly in a range of 10 to 100 .mu.m and then washed; and a preparation process of a polytetrafluoroethylene molding powder, characterized in that after the washing, mechanical force is applied to the washed powder in wet state for agglomeration granulation, thus giving particles having an average particle size in a range of 200 to 800 .mu.m.

Abstract: A process for preparing a polytetrafluoroethylene granular powder which comprises agitating primary particles of a finely divided polytetrafluoroethylene powder having an average particle size of not more than 100 .mu.m in an aqueous medium containing no organic liquid to form agglomerates while crushing an agglomerated powder in an apparatus having an agitating mechanism of the aqueous medium and a crushing mechanism of the agglomerates within a temperature range between not less than 20.degree. C. and less than 60.degree. C. According to the present invention, the dense polytetrafluoroethylene granular powder having the excellent electric properties and the high bulk density can be obtained without using the organic liquid which is expensive and whose use is restricted.

Abstract: A process for preparing a polytetrafluoroethylene granular powder which comprises subjecting a finely divided polytetrafluoroethylene to agitation in an aqueous medium consisting of water and organic liquid having a specific surface tension and being incompatible with water in an apparatus to form agglomerates, passing said agglomerates through a crushing mechanism and continuously recycling said crushed agglomerates for further agitation and crushing, said crushing mechanism being capable of lowering an average particle size of the agglomerates composed of primary particles having a particle size of 1 to 200.mu. by partially crushing agglomerated particles having an improper large particle size or abnormally large aggregates. The obtained polytetrafluoroethylene granular powder has a narrow size distribution and an improved flowability, in which at least 90% by weight of a whole granular powder has a particle size of at most 1000.mu.

Abstract: Elastomeric copolymer of vinylidene fluoride and at least one other fluorine-containing monomer containing 28 to 92% by mole of the vinylidene fluoride unit and having an intrinsic viscosity of 0.4 to 1.3 at 35.degree. C. in methyl ethyl ketone, which is prepared by a two-stage polymerization process of vinylidene fluoride monomer and at least one other fluorine-containing monomer wherein monomers are copolymerized in an aqueous medium in the presence of a water-soluble radical polymerization initiator at a first stage to give a first stage-copolymer having an intrinsic viscosity of 0.01 to 3.0 at 35.degree. C.