| 摘要 |
1290022 Tetrafluoroethylene copolymers E. I. DU PONT DE NEMOURS & CO 1 Dec 1969 [16 Dec 1968] 58630/69 Heading C3P A copolymer of tetrafluoroethylene with (1) a copolymerizable olefinic component selected from (a) alkyl vinyl ethers, (b) an olefin or mixture of olefins which is from 50 to 100 mole per cent of propylene, butene-1 or a mixture thereof, any remainder being ethylene or isobutylene, and (c) ethylene and isobutylene in about equimolar proportions, and (2) from 0À5 to 5% by weight of the copolymer of an aryloxyalkyl vinyl ether cure-site monomer of the formula where Y is an alkylene radical of 2 to 4 carbon atoms, X is an alkyl or alkoxy group containing not more than 4 carbon atoms and n is 0, 1 or 2, may be prepared by catalytically copolymerizing the monomers. The copolymer can be crosslinked by mixing with 0À5-5À0% by weight of the copolymer of a polymer of formaldehyde or methylol-containing condensation product of formaldehyde with urea, phenols or melamine or a carboxylate ester of the condensation product and curing at an elevated temperature under non-basic conditions. In the examples tetrafluoroethylene, propylene, methyl vinyl ether and 2-phenoxyethyl vinyl ether are copolymerized in the presence of water, ammonium persulphate, sodium hydroxide, sodium sulphite, ammonium perfluoro-octanoate, cupric sulphate and sodium carbonate and the terpolymers isolated by coagulation with dilute HCl or freezing. The polymers are cured with carbon black, 2,6-bishydroxy methyl-p-cresol (containing carbon black), paraformaldehyde, bromoethyl alkylated phenol formaldehyde resin, hexamethoxymethyl melamine, hexahydroxymethyl melamine, dimethylol urea, uncapped formaldehyde polymer, acetate-capped formaldehyde polymer optionally in the presence of 2 - propyl - p - toluene sulphonate, 2 - butyl - ptoluene sulphonate, maleic acid, o-phthalic acid, oxalic acid, perfluoro-octanoic acid and perfluorobenzoic acid. |
