Title:
METHOD FOR HIGH-PRESSURE POLYMERIZATION OF 1,1- DIFLUOROETHYLENE
Document Type and Number:
Japanese Patent JP3518811
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a continuous process for producing a polyvinylidene fluoride(PVDF) homopolymer or copolymer, wherein the comonomer is chosen from compounds each containing a vinyl group capable of being opened by the action of free radicals in order to polymerize, and which contains, directly attached to this vinyl group, at least one fluorine atom, a fluoroalkyl group or a fluoroalkoxy group.
SOLUTION: This method for the high-pressure polymerization of 1,1- difluoroethylene(VF2) comprises the following steps: (a) a flow of VF2, of optional comonomer and of radical initiator is introduced into a reactor maintained at a pressure of between 300 bar and 3,000 bar; (b) a flow of reaction mixture is removed from the reactor for the step (a) and introduced into a separator; (c) molten PVDF is recovered in the separator and purged continuously; (c1) the flow of PVDF from the step (c) is optionally introduced into a device to place it in the form of granules; and (d) VF2 and the optional comonomer are recovered in the separator and recycled into the step (a); wherein, the respective oxygen contents of the VF2 introduced in the step (a) and the remaining VF2 recycled are ≤5 ppm, preferably ≤1 ppm, more preferably 0.1-0.8 ppm.
Inventors:
Thierry, Senange
Application Number:
JP2001293927A
Publication Date:
April 12, 2004
Filing Date:
September 26, 2001
Export Citation:
Assignee:
Atofina
International Classes:
C08F2/02; C08F4/34; C08F4/44; C08F4/80; C08F14/22; (IPC1-7): C08F2/02; C08F4/34; C08F4/44; C08F4/80; C08F14/22
Attorney, Agent or Firm:
越場 隆