| abstract |
A base resistant, substantially amorphous fluoroelastomer comprising (1) 10-40 mole percent ethylene units, (2) 32-60 mole percent tetrafluoroethylene units, (3) 20-40 mole percent perfluoro(alkyl vinyl ether) units wherein the alkyl group contains 1-5 carbon atoms and (4) a cure-site monomer. Such fluoroelastomers are resistant to attack by amines, strong bases and hydrogen sulfide and possess a combination of good low temperature and high temperature properties and they are resistant to oil swell. To prevent fluoroelastomers of the type described above, with or without units of ethylene, that contain a bromine-containing olefin as a peroxide cure site from sticking to the mold cavity when cured an N,N,N′,N′-tetrasubstituted 1,8-diaminonaphthalene is added to the fluoroelastomer having the formula:n wherein R₁, R₂, R₃ and R₄ are independently alkyl groups of 1-6 carbon atoms, phenyl or benzyl, R₁ and R₂ and/or R₃ and R₄ can be joined to form a 5- or 6-membered heterocyclic ring in which a carbon atom can be replaced by an oxygen or a sulfur atom, R₁ and R₃ and/or R₂ and R₄ can be joined to form a heterocyclic ring of 6-20 carbon atoms in which a carbon atom can be replaced by an oxygen or a sulfur atom, X and Y are independently an alkyl group or an alkoxy group containing 1-4 carbon atoms and n is 0-3. |