E.i. Dupont De Nemours and Company

Dupont Dow Elastomers Inc.

Albert L Moore

Frantz Duvalsaint

Phan Linh Tang

Donald Frederick Lyons

Clare A Stewart

Isadore Swerlick

A novel emulsion polymerization process for the production of fluoroelastomers is disclosed wherein a partially fluorinated anionic surfactant of the formula F&mdash;(CF CF ) &mdash;CH CH SO M, where n is an integer from 2 to 9, or mixtures thereof, and M is a cation having a valence of 1, is used as the dispersing agent.

Process for producing fluoroelastomers with fluorinated anionic surfactants

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.

Process for producing fluoroelastomers

Process for producing fluorelastomers

Peroxide-curable fluoroelastomers and chlorofluoroelastomers are prepared in the presence of iodinated compounds, with iodine bonding to a substantial number of terminal positions on the fluoroelastomer, and comprising up to 3 weight percent of bromine-containing units selected from fluoroolefins and perfluoroalkyl perfluorovinyl ethers, and complementally at least 97 weight percent of either units of vinylidene fluoride, one or more fluoroolefins, and optionally perfluoroalkyl perfluorovinyl ethers, or units of tetrafluoroethylene, perfluoroalkyl perfluorovinyl ether, and ethylene. The resulting fluoroelastomers have improved processability, excellent strength and compression set properties, and are useful in the preparation of injection molded shaft seals, gaskets and other molded parts. The fluoroelastomer is prepared by a continuous emulsion polymerization process.

Peroxide-curable fluoroelastomers and chlorofluoroelastomers having

Peroxide-curable fluoroelastomers are prepared in the presence of iodinated compounds, with iodine bonding to a substantial number of terminal positions on the fluoroelastomer, and comprising up to 3 weight percent of bromine-containing units selected from fluoroolefins and perfluoroalkyl perfluorovinyl ethers, and complementally at least 97 weight percent of either units of vinylidene fluoride, one or more fluoroolefins, and optionally perfluoroalkyl perfluorovinyl ethers, or units of tetrafluoroethylene, perfluoroalkyl perfluorovinyl ether, and ethylene. The resulting fluoroelastomers have improved processability, excellent strength and compression set properties, and are useful in the preparation of injection molded shaft seals, gaskets and other molded parts. The fluoroelastomer is prepared by a continuous emulsion polymerization process.

Peroxide-curable fluoroelastomers having bromine and iodine curesites

Peroxide-curable fluoroelastomers having bromine an iodine curesites and

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.

Base resistant fluoroelastomers

Terpolymer consisting of 12 to 48% by weight TFE units, 7 to 24% by weight HFP units and 30 to 81% by weight VF.sub.2 units, provided that when the content of TFE units is less than 42% by weight, the content of HFP units is less than 15% by weight. Heat-stable films such as polyimide film can be coated with a coating comprising the terpolymer to provide heat-sealable film useful as wire insulation.

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Wilmington, DE, United States of America

Albert L Moore