Process for the discontinuous suspension polymerisation of vinylidene fluoride in aqueous medium.

摘要

Process for the noncontinuous polymerisation of vinylidene fluoride in an aqueous suspending medium with the use of an oil-soluble radical polymerisation initiator in the presence of a suspending agent in which the polymerisation takes place at supercritical temperature with delayed injection of a fraction of the vinylidene fluoride, the weight ratio of the fraction of vinylidene fluoride injected after a delay to that introduced initially into the polymerisation charge varying between 0.30 and 1.10. The process results in vinylidene fluoride polymers being obtained in the form of spherical particles whose apparent density is higher than 0.55 g/cm<3> and which can be varied at will up to approximately 0.90 g/cm<3> as a function of the ratio chosen. The vinylidene fluoride polymers obtained are suitable for powder-coating of articles, in particular for electrostatic spraying and rotational moulding.