Process for producing vinylidene fluoride resin

摘要

In a process for producing a vinylidene fluoride resin by polymerizing vinylidene fluoride or a mixture of vinylidene fluoride and a vinyl monomer copolymerizable with vinylidene fluoride, a portion of an iodide compound represented by the formula: X-Rf-X wherein Rf is a divalent organic group containing at least two divalent fluoroalkyl ether groups: and X's are independently an iodine atom or a fluorine atom, provided that at least one of the X's is an iodine atom; is added to start the polymerization, and the remainder of the iodide compound is further added dividedly at least twice in the course of the polymerization. This process enables to obtain a vinylidene fluoride resin having a viscosity-average molecular weight of 150,000 or more and also having a superior water repellency. This resin has good mechanical strength and release properties and also can be well processed into films.