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.
Type:
Grant
Filed:
March 22, 2001
Date of Patent:
March 19, 2002
Assignee:
DuPont Dow Elastomers, L.L.C.
Inventors:
Ming-Hong Hung, Walter Werner Schmiegel
Abstract: Fluoroelastomers having copolymerized units of vinylidene fluoride major monomer, at least one other fluorinated major monomer, and at least one cure site monomer are prepared in an aqueous suspension polymerization process using an initiator consisting essentially of a solution of an oil soluble peroxide in a water-soluble hydrocarbon solvent.
Abstract: Ethylene copolymer elastomer compositions, acrylate rubber compositions, nitrile rubber compositions, fluoroelastomer compositions, and chlorinated elastomer compositions are provided which are curable by exposure to UV radiation. The compositions are particularly suited for production of elastomeric seals using hot melt equipment and a gasketing in place technique.
Abstract: This invention is directed to a seal for installation into an annular groove of dovetail configuration that has a mouth, two side walls depending from the mouth that extend away from each other and a base wall that is connected to the two side walls thereby forming the dovetail configuration.
Abstract: Copolymers having copolymerized units of vinylidene fluoride, perfluoro(alkyl vinyl) ether, 2-hydropentafluoropropene, and, optionally, tetrafluoroethylene, exhibit excellent low temperature properties and processability when cured with polyhydroxy compounds or amines.
Type:
Grant
Filed:
August 20, 1999
Date of Patent:
December 11, 2001
Assignee:
DuPont Dow Elastomers, L.L.C.
Inventors:
Stephen Bowers, Walter Werner Schmiegel
Abstract: Fluoroelastomers containing copolymerized units of vinylidene fluoride, perfluoro(alkyl vinyl)ether, 2-hydropentafluoropropene, and, optionally, tetrafluoroethylene, and having an iodine atom present at some polymer chain ends, exhibit excellent low temperature properties and processability when dual cured with both polyhydroxy compounds and organic peroxides.
Abstract: Curable fluoroelastomer compositions comprising a fluoroelastomer, a curative for the fluoroelastomer, and a molecular sieve additive exhibit a reduced tendency to sponge during the curing process.
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.
Type:
Grant
Filed:
August 4, 1999
Date of Patent:
August 28, 2001
Assignee:
DuPont Dow Elastomers L.L.C.
Inventors:
James Daniel MacLachlan, Peter Arnold Morken, Walter Werner Schmiegel, Kohtaro Takahashi
Abstract: Fluoroelastomers having copolymerized units of vinylidene fluoride major monomer, at least one other fluorinated major monomer, and at least one cure site monomer are prepared in an aqueous suspension polymerization process using an initiator consisting essentially of a solution of an oil soluble peroxide in a water-soluble hydrocarbon solvent.
Abstract: Elastomeric vinylidene fluoride-containing copolymers are cured by a sequential process. In a first step, gum fluoroelastomer is mixed at a temperature of 150° C.-250° C. in the presence of an organic base and metal oxide or metal hydroxide to generate an unsaturated product. The unsaturated product is mixed with a polyhydroxy compound, polyamine, or organic peroxide and the resultant compounded fluoroelastomer is crosslinked.
Abstract: Curable perfluoroelastomer compositions are disclosed that comprise ammonia and uncured perfluorinated elastomers having copolymerized units of nitrile-containing cure site monomers. Such compositions are curable at low temperatures. In addition, curable perfluoroelastomer compositions are disclosed wherein ammonia functions as a cure rate accelerator in the presence of other curing agents.
Type:
Grant
Filed:
August 6, 1999
Date of Patent:
April 24, 2001
Assignees:
E.I. DuPont de Nemours and Company, DuPont Dow Elastomers, L.L.C.
Inventors:
Peter Arnold Morken, Walter Werner Schmiegel
Abstract: Curable perfluoroelastomer compositions comprising A) a perfluoroelastomer having copolymerized units of tetrafluoroethylene, a perfluoro(vinyl ether), and a nitrile-containing cure site monomer, B) anhydrous silica, and C) a curing agent exhibit excellent thermal stability and reduced tendency to generate hydrogen fluoride under high temperature conditions.
Abstract: A fluoroelastomer latex is produced that is capable of forming films having excellent water resistance. In a first step, polymerization of fluorinated monomers is carried out in the presence of fluorinated surfactants at a pH of 3-8. The pH of the resultant fluoroelastomer emulsion composition is then adjusted to 5-9 and the emulsion is concentrated to yield a solids-rich latex.
Abstract: Processability of non-fluorinated melt-processible polymers is improved by introducing a process aid comprising a fluoroelastomer latex or aqueous fluoropolymer dispersion to the non-fluorinated polymer and extruding the blend.
Abstract: Elastomeric vinylidene fluoride-containing copolymers are cured by a sequential process. In a first step, gum fluoroelastomer is mixed at a temperature of 150.degree. C.-250.degree. C. in the presence of an organic base and metal oxide or metal hydroxide to generate an unsaturated product. The unsaturated product is mixed with a polyhydroxy compound, polyamine, or organic peroxide and the resultant compounded fluoroelastomer is crosslinked.
Abstract: Crystalline polychloroprene compositions comprise mercaptan-modified or xanthogen disulfide-modified 2-chloro-1,3-butadiene homopolymers having gel contents of 5-80 percent by weight. The polymers are prepared by free radical emulsion polymerization at a temperature of 5.degree.-20.degree. C. to a conversion of 70-95 percent in the presence of 2.5.times.10.sup.-4 -5.5.times.10.sup.-4 moles of mercaptan or xanthogen disulfide modifier per mole of 2-chloro-1,3-butadiene.
Type:
Grant
Filed:
January 10, 1997
Date of Patent:
June 30, 1998
Assignee:
Dupont Dow Elastomers
Inventors:
Lance Alan Christell, Richard Misak Tabibian
Abstract: Polychloroprene latex adhesive compositions which comprise a) mercaptan-modified or xanthogen disulfide-modified 2-chloro-1,3-butadiene homopolymers having gel contents of 5-.[.70.]..Iadd.78.7 .Iaddend.percent by weight, b) 1 to 75 parts by weight of rosin per 100 parts by weight of a), and c) sufficient water to provide a solids content of 25-65 weight percent based on the weight of component a) exhibit excellent heat resistance and green bond strength.
Type:
Grant
Filed:
November 26, 1997
Date of Patent:
March 14, 2000
Assignee:
DuPont Dow Elastomers, L.L.C.
Inventors:
Lance Alan Christell, Richard Misak Tabibian