High melting fluoropolymers

摘要

The invention relates to a method for making copolymers of 2,3,3,3-tetrafluoropropene and vinylidene fluoride by an emulsion polymerization process having unexpectedly high melting temperatures, even at low crystallinity levels. The invention involves adjusting the microstructure of the copolymers through a controlled polymerization to obtain controlled microstructure copolymers with unique properties, including those with high melting temperature and low crystallinity.

主权项

1. A controlled microstructure copolymer composition comprising a copolymer consisting of from 15 to 65 weight percent of 2,3,3,3-tetrafluoropropene monomer units and 35 to 85 weight percent of vinylidene fluoride monomer units, wherein said copolymer is formed by a semi-batch process in which the weight ratio of 2,3,3,3-tetrafluoropropene to vinylidene fluoride in the initial charge is from 0.1 to 0.75 times, or from 1.5 to 10 times the steady state monomer ratio in the delay feed.