E.i. Dupont De Nemours and Company

The Chemours Company Fc, LLC

Subhash Vishnu Gangal

Paul Douglas Brothers

Dipti Dilip Khasnis

Gregory Allen Chapman

Adam Paul Smith

Satish C Malhotra

Jon Lee Howell

Charles W Stewart, Sr

Jerrel Charles Anderson

Dewey Lynn Kerbow

Allan Harold Olson

Lam H Leung

A process is provided for the polymerization of fluoromonomer to an dispersion of fluoropolymer particles in an aqueous medium in a polymerization reactor, by (a) providing the aqueous medium in the reactor, (b) adding the fluoromonomer to the reactor, (c) adding initiator to the aqueous medium, the combination of steps (b) and (c) being carried out essentially free of hydrocarbon-containing surfactant and resulting in the kickoff of the polymerization of the fluoromonomer, and (d) metering hydrocarbon-containing surfactant into the aqueous medium after the kickoff of polymerization, e.g. after the concentration of the fluoropolymer in the aqueous medium is at least 0.6 wt %, the metering being at a rate reducing the telogenic activity of said surfactant while maintaining surface activity.

Aqueous polymerization of perfluoromonomer using hydrocarbon surfactant

A process comprising polymerizing at least one fluorinated monomer in an aqueous medium containing initiator and polymerization agent to form an aqueous dispersion of particles of fluoropolymer, the polymerization agent comprising:

Aqueous polymerization of fluorinated monomer using polymerization agent comprising fluoropolyether acid or salt and short chain fluorosurfactant

A composition comprising a mixture of fluoropolyether acids or salts having a number average value of about 800 to about 2500 g/mol. The amount of fluoropolyether acids or salt in the mixture having a molecular weight of not more than 500 g/mol is not more than 50 ppm by weight of the total amount of fluoropolyether acids or salts in the mixture. The amount of fluoropolyether acids or salts in the mixture having a molecular weight of 2500 g/mol or greater is not more than 40% by weight of the total amount of fluoropolyether acids or salts in the mixture. Preferably the fluoropolyether acids or salts comprise an anionic group selected from the group consisting of carboxylate, sulfonate, sulfonamide anion and phosphonate. Also disclosed is an aqueous dispersion polymerization process for fluoropolymer manufacture employing polymerization agent comprising the specified mixture of fluoropolyether acids or salts.

Aqueous polymerization of fluorinated monomer using a mixture of fluoropolyether acids or salts

Process for polymerizing fluoromonomer to form an aqueous dispersion of fluoropolymer particles including: (a) providing an aqueous medium in a polymerization reactor, (b) adding nucleating additive comprising polyalkylene oxide having a number average molecular weight of about 50 to about 2000 to the aqueous medium in an amount of about 0.1 ppm to about 50 ppm based on water in the aqueous medium, (c) exposing the nucleating additive to oxidizing agent to form a dispersion of oleophilic nucleation sites in the aqueous medium; (d) pressurizing the reactor by adding fluoromonomer, and (e) adding polymerization initiator to the aqueous medium to cause the polymerizing of the fluoromonomer to form fluoropolymer particles dispersed in the aqueous medium.

Employing polyalkylene oxides for nucleation in aqueous polymerization of fluoromonomer

A process for reducing thermally induced discoloration of fluoropolymer resin produced by polymerizing fluoromonomer in an aqueous dispersion medium to form aqueous fluoropolymer dispersion and isolating the fluoropolymer from the aqueous medium to obtain fluoropolymer resin. The process comprises contacting the aqueous fluoropolymer dispersion with sorbent.

Fluoropolymer resin treatment employing sorbent to reduce fluoropolymer resin discoloration

A process is provided for polymerizing fluoromonomer in an aqueous medium, wherein a dispersion of essentially surfactant-free hydrocarbon-containing oleophilic nucleation sites is first formed in the aqueous medium, and then polymerization is commenced to form a dispersion of fluoropolymer particles at the oleophilic nucleation sites, wherein the nucleation sites can be derived from hydrocarbon-containing compound. The surfactant used to stabilize the fluoropolymer dispersion can also be hydrocarbon-containing.

Nucleation in aqueous polymerization of fluoromonomer

Process for reducing thermally induced discoloration of fluoropolymer resin produced by polymerizing fluoromonomer in an aqueous dispersion medium to form aqueous fluoropolymer dispersion and isolating fluoropolymer from said aqueous medium by separating wet fluoropolymer resin from the aqueous medium and drying to produce fluoropolymer resin. The process comprises exposing the wet fluoropolymer resin to an oxygen source during drying.

Drying wet fluoropolymer resin and exposing to oxygen source to reduce discoloration

Process for reducing thermally induced discoloration of fluoropolymer resin produced by polymerizing fluoromonomer in an aqueous medium to form aqueous fluoropolymer dispersion and isolating said fluoropolymer from said aqueous medium to obtain said fluoropolymer resin. The process comprises: heating the fluoropolymer resin to a temperature of about 160&#xb0; C. to about 400&#xb0; C.; and exposing the heated fluoropolymer resin to an oxygen source.

Fluoropolymer resin treatment employing heating and oxygen source to reduce discoloration

Process for reducing thermally induced discoloration of melt-processible fluoropolymer resin produced by polymerizing fluoromonomer in an aqueous medium to form aqueous fluoropolymer dispersion and isolating said fluoropolymer from said aqueous medium to obtain said fluoropolymer resin. The process comprises melt extruding said fluoropolymer resin to produce molten fluoropolymer resin; and exposing said molten fluoropolymer resin to an oxygen source during said melt extruding.

Fluoropolymer resin treatment employing melt extrusion and exposure to oxygen source to reduce discoloration

A polymerization process is provided, comprising polymerizing fluoromonomer in an aqueous medium to form a dispersion of fluoropolymer particles in the aqueous medium, said polymerizing being carried out in the presence of (i) polymerization initiator, and (ii) hydrocarbon-containing surfactant stabilizing the dispersion of fluoropolymer particles, the hydrocarbon-containing surfactant being passivated to reduce its the telogenic behavior.

Reducing the telogenic behavior of hydrocarbon-containing surfactants in aqueous dispersion fluoromonomer polymerization

Process for reducing thermally induced discoloration of fluoropolymer resin produced by polymerizing fluoromonomer in an aqueous dispersion medium to form aqueous fluoropolymer dispersion and isolating said fluoropolymer from the aqueous medium by separating fluoropolymer resin in wet form from the aqueous medium and drying to produce fluoropolymer resin in dry form. The process comprises:

Employing pretreatment and fluorination of fluoropolymer resin to reduce discoloration

Process for reducing thermally induced discoloration of fluoropolymer resin produced by polymerizing fluoromonomer in an aqueous dispersion medium to form aqueous fluoropolymer dispersion and isolating said fluoropolymer from said aqueous medium to obtain said fluoropolymer resin. The process comprises exposing the aqueous fluoropolymer dispersion to ultraviolet light in the presence of an oxygen source.

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Hockessin, DE, United States of America

Subhash Vishnu Gangal