Abstract:
Fluoroelastomers which contain copolymerized units of a fluoroolefin cure site monomer of the general formula: Rf—(CH2CF2)n—CH═CF2, wherein Rf is a C1-C6 perfluoroalkyl group or a C1-C6 perfluoroalkoxy group and n is an integer from 1-3, exhibit excellent physical properties and processability when cured with polyhydroxy compounds.
Abstract:
Disclosed herein is a novel class of fluorovinyl ether monomers which are useful as cure site monomers in fluoroelastomers, a process for the preparation of these fluorovinyl ether monomers, and fluoroelastomer copolymer compositions that contain copolymerized units of these fluorovinyl ether monomers.
Abstract:
Polyhydroxy curable fluoroelastomers that are substantially free of nucleophilic endgroups are grafted with a monophenol having at least one pendant group. The resulting grafted fluoroelastomers retain most of the properties of the original elastomers including excellent pre-vulcanization characteristics, while incorporating pendant groups which may be used for further modification, crosslinking or for changing the physical properties (e.g. Tg) of the fluoroelastomer.
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 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) perfluoroalkyl ethylenes and ii) perfluoroalkoxy ethylenes. Such fluoroelastomers may be vulcanized with polyhydroxy curing agents. The resulting vulcanized 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.
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 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.
Abstract:
Perfluoroelastomer compositions comprising perfluoroelastomers having copolymerized units of tetrafluoroethylene, a perfluoro(vinyl ether), and a nitrile-containing cure site monomer are cured with compounds that are capable of generating ammonia at temperatures of 40° C.-330° C. to produce cured compositions having excellent thermal stability. The ammonia-generating compounds also act as cure accelerators in perfluoroelastomer compositions that incorporate other curing agents.
Abstract:
Curable perfluoroelastomer compositions are prepared in the presence of an initiator system comprising a mixture of a persulfate salt and a reducing agent wherein the amount of reducing agent present is no more than 20 mole percent of the total initiator system. The perfluoroelastomer is isolated and decarboxylated, thereby providing a product having excellent processability.
Abstract:
Compositions of specialty fluoroelastomers containing copolymerized units of tetrafluoroethylene, propylene, optionally vinylidene fluoride, and a cure site monomer selected from the group consisting of i) trifluoroethylene, ii) 3,3,3-trifluoropropene-1, iii) 1,2,3,3,3-pentafluoropropylene, iv) 1,1,3,3,3-pentafluoropropylene, and v) 2,3,3,3-tetrafluoropropene are readily curable with polyhydroxy curing systems. The resulting cured articles have a combination of excellent resistance to alkaline fluids, superior tensile properties and compression set resistance.
Abstract:
Curable perfluoroelastomer compositions are prepared in the presence of an initiator system comprising a mixture of a persulfate salt and a reducing agent wherein the amount of reducing agent present is no more than 20 mole percent of the total initiator system. The perfluoroelastomer is isolated and decarboxylated, thereby providing a product having excellent processability.