Perfluoroelastomer

1 . A peroxide curable perfluoroelastomer comprising:

recurring units derived from tetrafluoroethylene (TFE);

recurring units derived from perfluoroethylvinylether (EVE), in an amount of between 2 and 17% by moles, with respect to total recurring units derived from TFE, perfluoromethylvinylether (MVE) and EVE; and

recurring units derived from perfluoromethylvinylether (MVE), in an amount of between 23 and 35% by moles, with respect to total recurring units derived from TFE, perfluoromethylvinylether (MVE) and EVE.

2 . The perfluoroelastomer of claim 1 , said perfluoroelastomer comprising, in addition to recurring units derived from TFE, EVE and MVE, recurring units derived from one or more per(halo)fluoromonomer (PFM).

3 . The perfluoroelastomer of claim 2 , wherein said per(halo)fluoromonomer (PFM) is selected from the group consisting of:

C 3 -C 8 perfluoroolefins;

bromo- and/or iodo C 2 -C 8 (halo)fluoroolefins;

per(halo)fluoroalkylvinylethers complying with general formula CF 2 ═CFOR f3 in which R f3 is a C 2 -C 6 per(halo)fluoroalkyl, optionally comprising iodine or bromine atoms;

per(halo)fluoro-oxyalkylvinylethers complying with general formula CF 2 ═CFOX 01 , in which X 01 is a C 1 -C 12 per(halo)fluorooxyalkyl having one or more ether groups, optionally comprising iodine or bromine atoms;

per(halo)fluoro-methoxy-alkylvinylethers complying with general formula CF 2 ═CFOCF 2 OR f4 in which R f4 is a C 1 -C 6 per(halo)fluoroalkyl, or a C 1 -C 6 per(halo)fluorooxyalkyl having one or more ether groups, optionally comprising iodine or bromine atoms; and

per(halo)fluorodioxoles of formula:

wherein each of R f3 , R f4 , R f5 , R f6 , equal to or different from each other, is independently a fluorine atom, or a C 1 -C 6 per(halo)fluoroalkyl group, optionally comprising one or more oxygen atom, and optionally comprising iodine or bromine atoms.

4 . The perfluoroelastomer of claim 1 , said perfluoroelastomer comprising recurring units derived from a bis-olefin of general formula (I) here below:

wherein:

R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 , which are identical or different from each other, are H or C 1 -C 5 alkyl; and

Z is a linear or branched C 1 -C 18 alkylene or cycloalkylene radical, optionally containing oxygen atoms, preferably at least partially fluorinated, or a (per)fluoropolyoxyalkylene radical.

5 . The perfluoroelastomer of claim 1 , said perfluoroelastomer comprising at least one of:

iodine and/or bromine atoms in the chain and/or in the end position of the perfluoroelastomer chain; and

recurring units derived from a cure-site monomer comprising a functional group of —CN type.

6 . The perfluoroelastomer of claim 5 , said perfluoroelastomer consisting essentially of recurring units derived from TFE, EVE and MVE, and, optionally from a bis-olefin of general formula (I):

wherein:

R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 , which are identical or different from each other, are H or C 1 -C 5 alkyl; and

Z is a linear or branched C 1 -C 18 alkylene or cycloalkylene radical, optionally containing oxygen atoms, preferably at least partially fluorinated, or a (per)fluoropolyoxyalkylene radical, and further comprising iodine and/or bromine atoms in end-groups.

7 . The perfluoroelastomer of claim 6 , said perfluoroelastomers consisting essentially of:

from 60 to 75% moles of recurring units derived from TFE;

from 2 to 17% moles of recurring units derived from EVE;

from 23 to 35% moles of recurring units derived from MVE; and

further comprising iodine and/or bromine in end-groups.

8 . The perfluoroelastomer of claim 7 , said perfluoroelastomers consisting essentially of:

from 65 to 70% moles of recurring units derived from TFE;

from 4 to 10% moles of recurring units derived from EVE;

from 25 to 30% moles of recurring units derived from MVE; and

further comprising iodine and/or bromine in end-groups.

9 . A process for manufacturing the perfluoroelastomer according to claim 1 .

10 . A curable composition comprising the perfluoroelastomer according to claim 1 , and further comprising at least one peroxide, said peroxide being present in an amount of 0.05 to 10%, by weight relative to said perfluoroelastomer.

11 . The curable composition of claim 10 , wherein said peroxide is selected from the group consisting of di-tert-butyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, dicumyl peroxide, dibenzoyl peroxide, di-tert-butyl perbenzoate, and bis[1,3-dimethyl-3-(tert-butylperoxy)butyl]carbonate.

12 . The curable composition of claim 10 , said composition comprising one or more additional ingredients selected from the group consisting of:

(a′) vulcanization coagents, in an amount generally of between 0.5% and 10% by weight relative to said perfluoroelastomer;

(b′) a metallic compound, in an amount of between 1% and 15% by weight relative to the polymer, said metallic compound being selected from the group consisting of oxides and hydroxides of divalent metals, optionally combined with a salt of a weak acid;

(c′) acid acceptors of metal non-oxide type;

(d′) other conventional additives selected from the group consisting of thickening fillers, pigments, antioxidants, and stabilizers.

13 . Cured articles made from the perfluoroelastomer of claim 1 .

14 . A process for manufacturing cured articles, said process comprising:

providing the curable perfluoroelastomer composition of claim 10 ;

vulcanizing-moulding said curable perfluoroelastomer composition to yield shaped pre-formed sealing articles; and

optionally, thermally post-treating said shaped pre-formed sealing articles to yield the cured articles.

15 . Cured articles made from the curable composition of claim 10 .