Fluororubber coating composition
An amino group-containing metal compound such as a coupling agent having an amino group is dispersed in a fluoroelastomer coating composition comprising a fluoroelastomer and a polyol curing agent which are dissolved or dispersed in a liquid medium. The resulting fluoroelastomer coating composition can form an elastomer coating layer directly on a metal surface using no primer, and improve antifreeze resistance and deterioration of the coating film after compression at high temperatures for a long time.
1. A gasket of an automobile engine comprising:
a metal plate, and
a coated film formed on at least one surface of the metal plate from a fluoroelastomer coating composition which comprises a liquid medium, a fluoroelastomer, a polyol curing agent, an amino group-containing metal compound, a curing aid and an organic acid having 1 to 12 carbon atoms as a stabilizer which are dissolved or dispersed in the liquid medium, wherein the amino group-containing metal compound is present in an amount of 6 to 30 parts by weight and the curing aid is present in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the fluoroelastomer,
wherein the curing aid is selected from the group consisting of quaternary alkyl-aralkyl-ammonium salts, quaternary 1-8 diaza-bicyclo[5.4.0]-7-undecenium salts, tertiary amines and quaternary phosphonium salts.
2. The gasket according to claim 1 , wherein the amino group-containing metal compound is present in an amount of 6 to 15 parts by weight.
3. The gasket according to claim 1 , wherein the metal in the amino group-containing metal compound is at least one metal selected from the group consisting of Si, Al, Ti and Zr.
4. The gasket according to claim 1 , wherein the fluoroelastomer coating composition further comprises a fluororesin.
5. The gasket according to claim 4 , wherein the fluororesin is at least one fluororesin selected from the group consisting of tetrafluoroethylene-hexafluoropropylene copolymers, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers and tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymers.
6. The gasket according to claim 1 , wherein said fluoroelastomer coating composition consists essentially of the liquid medium, the fluoroelastomer, the polyol curing agent, the amino group-containing metal compound, the curing aid and the organic acid having 1 to 12 carbon atoms as a stabilizer which are dissolved or dispersed in the liquid medium.