Curable base-resistant fluoroelastomers
View Patent ↗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 ether units selected from the group consisting of perfluoro(alkyl vinyl ethers), perfluoro(alkyl alkenyl ethers) and perfluoro(alkoxy alkenyl ethers), and (4) 0.1 to 15 mole percent of a cure site monomer selected from the group consisting of i) 3,3,3-trifluoropropene-1, ii) trifluoroethylene, iii) 1,2,3,3,3-pentafluoropropylene, iv) 1,1,3,3,3-pentafluoropropylene, and v) 2,3,3,3-tetrafluoropropene. Such fluoroelastomers may be vulcanized with polyhydroxy curatives. The resulting vulcanized fluoroelastomer compositions 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.
1. A specialty fluoroelastomer comprising copolymerized units of 10 to 40 mole percent ethylene; 20 to 40 mole percent perfluoro ether selected from the group consisting of perfluoro(alkyl vinyl ethers), perfluoro(alkyl alkenyl ethers) and perfluoro(alkoxy alkenyl ethers); 32-60 mole percent tetrafluoroethylene; and 0.1 to 15 mole percent of a cure site monomer selected from the group consisting of i) 3,3,3-trifluoropropene-1, ii) trifluoroethylene, iii) 1,2,3,3,3-pentafluoropropylene, iv) 1,1,3,3,3-pentafluoropropylene, and v) 2,3,3,3-tetrafluoropropene.
2. A specialty fluoroelastomer of claim 1 wherein said copolymerized units of ethylene are present in an amount between 20 and 40 mole percent; said copolymerized units of perfluoro ether in an amount between 20 and 30 mole percent; said copolymerized units of tetrafluoroethylene in an amount between 40 and 50 mole percent and said copolymerized units of cure site monomer in an amount between 2 and 10 mole percent.
3. A specialty fluoroelastomer of claim 2 wherein said cure site monomer is 3,3,3-trifluoropropene-1.
4. A specialty fluoroelastomer of claim 2 wherein said perfluoro ether is perfluoro(methyl vinyl ether).