Rapidly crosslinking fluoropolymer
AssigneeBayer Aktiengesellschaft
InventorsDavid B. Harrison, Wilhelm-Franz Biener
Life of this patent
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Abstract
The invention relates to a rapidly cross-linking liquid fluoropolymer that contains as the essential components tetrafluoroethylene and at least one compound from the group consisting of diiodomethane, 1,2-diiodo- 1,1 -difluoroethane, 1-iodo-2-bromo-1,1-difluoroethane, 1-bromo-2-iodo- 1,1-difluoroethane and/or 1,2-dibromo-1,1difluoroethane that has certain fractions of the final group of the formula —CH2—X with X=Br and/or iodine, and iodine/bromine contents in the range of from 0.05 to 1 wt.-%. and that has a defined molecular weight and viscosity. The invention further relates to a method for producing said fluoropolymer and to its use.
Claims10
Liquid fluoropolymer which can be produced from tetrafluoroethylene and optionally other fluorine-containing and/or non-fluorine-containing monomers and at least one co-compound from the group diiodomethane, 1,2-diiodo-1,1-difluoroethane, 1-iodo-2-bromo-1,1-difluoroethane, 1-bromo-2-iodo-1,1-difluoroethane and/or 1,2-dibromo-1,1-difluoroethane, in which at least 80% of the terminal groups have the formula —CH2-1 and/or —CH2—Br and which has a complex viscosity at 100° C. and ω=6.3 s−1 of 0.01 to 30 kPas and a temperature index, calculated as the quotients of the viscosities at 40 and 100° C. of 3 to 250, characterised in that, the fluoropolymer
- a) has more than 10 mol% repeated units derived from tetrafluoroethylene,
- b) contains in the range of 0.05 to 1 wt.% iodine and/or bromine and
- c) has an average molecular weight (number average Mn) of over 25,000 g/mol.
Process for the production of fluoropolymers, characterised in that tetrafluoroethylene and optionally other fluorine-containing and/or non-fluorine-containing monomers are radically polymerised in the presence of at least one co-compound from the group diiodomethane, 1,2-diiodo-1,1-difluoroethane, 1-iodo-2-bromo-1,1-difluoroethane, 1-bromo-2-iodo-l,1-difluoroethane and/or 1,2-dibromo-1,1-difluoroethane and in the presence of an initiator and/or other auxiliary substances at temperatures of −20 to +130° C.
Dependencies are inferred from the claim text.