Fast-curing perfluoroelastomer composition

Claim 1

A curable perfluoroelastomer composition comprising (A) a perfluoroelastomer comprising copolymerized units of (1) a perfluoroolefin; (2) a perfluorovinyl ether selected from the group consisting of perfluoro(alkyl vinyl) ethers, perfluoro(alkoxy vinyl) ethers, and mixtures thereof; and (3) a cure site monomer having at least one nitrile group, selected from the group consisting of fluorinated olefins having at least one nitrile group, fluorinated vinyl ethers having at least one nitrile group, and mixtures thereof; wherein the perfluoroelastomer is characterized by i) having a plurality of carbonyl-containing endgroups selected from the group consisting of carboxyl endgroups, carboxylate endgroups, carboxamide endgroups, and mixtures thereof and ii) being substantially free of ionizable or ionized endgroups other than those having carbonyl-containing functional groups; and wherein the integrated absorbance ratio of the carbonyl-containing endgroups is greater than 0.1, the integrated absorbance ratio being determined by calculating the ratio of the integrated peak intensity within the range of 1620-1840 cm -1 to that within the range of 2220-2740 cm -1 , as measured on a Fourier transform infrared spectrum of the perfluoroelastomer; and (B) about 0.1 to about 10 parts by weight per hundred parts by weight perfluoroelastomer of an organotin curing agent wherein the perfluoroelastomer composition is characterized by having a t s 2 of less than 4 minutes, when measured with a moving die rheometer at a moving die frequency of 1.66 Hertz, using an oscillation amplitude of ±0.5 degrees at 199° C.