Patent ID: 8354472

Claim:
An ionically crosslinkable fluoroelastomer composition comprising: (a) at least one fluoroelastomer, said fluoroelastomer (F) being free from recurring units derived from nitrogen-containing cure-site monomers; (b) at least one ionically crosslinking system comprising at least one accelerator and at least one curing agent; (c) from 0.5 to 20 weight parts, per hundred parts of fluoroelastomer, of at least one polar compound having boiling point of 150° C. or less, selected from the group consisting of: alcohols having formula: R H —OH wherein R H is a C 1-12 hydrocarbon group, aliphatic or aromatic, substituted or unsubstituted, linear or branched; aldehydes having formula: wherein R′ H is a C 1-12 hydrocarbon group, aliphatic or aromatic, substituted or unsubstituted, linear or branched; ketones having formula: wherein R″ H groups, equal or different from each other, are C 1-6 hydrocarbon groups, aliphatic or aromatic, substituted or unsubstituted, linear or branched; and esters having formula: wherein R′″ H groups, equal or different from each other, are C 1-6 hydrocarbon groups, aliphatic or aromatic, substituted or unsubstituted, linear or branched, wherein the polymer (F) is selected from the group consisting of: VF 2 /hexafluoropropylene (HFP) copolymers comprising from 60 to 85% by moles of VF 2 and from 40 to 15% by moles of HFP; VF 2 /HFP/TFE terpolymers comprising 45 to 85% by moles of VF 2 , 15 to 45% by moles of HFP and up to 30% by moles of TFE, VF 2 /perfluoro(alkyl vinyl) ether/TFE terpolymers, comprising from 50 to 80% by moles of VF 2 , 5 to 50% by moles of perfluoro(alkyl vinyl) ether of formula CF 2 ═CF—O—R′ f , wherein R′ f is a C l-6 perfluoroalkyl group, and up to 20% by moles of TFE; VF 2 /ethylene/HFP/TFE polymers, from 20 to 30% by moles of VF 2 , from 10 to 30% by moles of ethylene (E) and from 10 to 30% by moles of TFE, the remaining being HFP; VF 2 /E/perfluoro(alkyl vinyl) ether/TFE polymers comprising from 20 to 30% by moles of VF 2 , from 10 to 30% by moles of ethylene, from 18 to 27% by moles of perfluoro(alkyl vinyl) ether of formula CF 2 ═CF—O—R′ f , wherein R′ f is a C 1-6 perfluoroalkyl group, and from 10 to 30% by moles of TFE; perfluoro(alkyl vinyl) ether/TFE copolymers comprising from 20 to 50% by moles of perfluoro(alkyl vinyl) ether of formula CF 2 ═CF—O—R′ f , wherein R′ f is a C 1-6 perfluoroalkyl group, and from 50 to 80% by moles of TFE: and VF 2 /HFP/E/TFE polymers, comprising from 4 to 75% by moles of VF 2 , from 12 to 40% by moles of HFP, up to 35% by moles of E and from 2 to 60% by moles of TFE.