| 主权项 |
1. A melt-processable fluoropolymer composition comprising a fluoropolymer with a core-shell structure, the fluoropolymer having from 50 to 95% by weight based on the total weight of the composition of a first fluoropolymer portion, wherein the first fluoropolymer portion has a relaxation exponent of from 0.93 to 1.0, and from 5 to 50% by weight based on the total weight of the composition of a second fluoropolymer portion, wherein the second fluoropolymer portion has a relaxation exponent of from 0.3 to 0.90, has a technological coefficient wherein the first fluoropolymer portion is melt-processable and thermoplastic end has a melting point of from 100° C to 320° C and the second fluoropolymer portion is melt-processable and thermoplastic end has a melting point of from 112° C to 320° C, further wherein the relative amount of each of the same monomeric unit in the first fluoroploymer portion is within 40% by weight of the relative amount of the same monomeric unit in the second fluoropolymer portion, further wherein the composition has a strain hardening coefficient S of from 1.2 to 1.78, measured at an elongational rate of 1 1/s, further wherein the first fluoropolymer portion is selected from the group consisting of a copolymer of tetrafluoroethylene and hexafluoropropylene, a copolymer of tetrafluoroethylene and perfluorovinyl ether, a copolymer of vinylidene fluoride and hexafluoropropylene, a copolymer of tetrafluoroethylene and vinylidene fluoride, a copolymer of chlorotrifluoroethylene and vinylidens fluoride, a copolymer of vinylidene fluoride and perfluorovinyl, a terpolymer of tetrafluoroethylene, hexafluoropropylene and perfluorovinyl ether, a terpolymer of tetrafluoroethylene, vinylidene fluoride and hexafluoropropylene, and a terpolymer of vinylidene fluoride, tetrafluoroethylene and perfluorovinyl ether and wherein the second fluoropolymer portion is derived from the group consisting of (a) one or more gaseous fluorinated monomers, and (b) one or more modifiers selected from the group consisting of (i) olefins having a bromine or iodine atom bonded to a carbon of the double bond of the olefin, (ii) olefins corresponding to formula (I);
Z2C═CZ—Rf—Br (I)wherein each Z independently represents hydrogen, fluoride, bromine, chlorine or iodine, Rf is a perfluoroalkylene group, a perfluorooxyalkylene group or a perfluoropolyther group; (iii) olefins corresponding to the formula CH2═CH —Rf—CH═CH2, wherein Rf is selected from the group consisting of a divalent perfluoroaliphatic group, originally containing one or more O atoms, a perfluoroarylene group, and a perfluoroalkarylene group; and (iv) mixtures thereof. |
