Patents by Inventor Subhash Vishnu Gangal

Subhash Vishnu Gangal has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8563670
    Abstract: 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.
    Type: Grant
    Filed: November 9, 2011
    Date of Patent: October 22, 2013
    Assignee: E I du Pont de Nemours and Company
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal, Dipti Dilip Khasnis
  • Patent number: 8519072
    Abstract: 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: fluoropolyether acid or salt thereof having a number average molecular weight of at least about 800 g/mol; and fluorosurfactant having the formula: [R1—On-L-A?]Y+ wherein: R1 is a linear or branched partially or fully fluorinated aliphatic group which may contain ether linkages; n is 0 or 1; L is a linear or branched alkylene group which may be nonfluorinated, partially fluorinated or fully fluorinated and which may contain ether linkages; A? is an anionic group selected from the group consisting of carboxylate, sulfonate, sulfonamide anion, and phosphonate; and Y+ is hydrogen, ammonium or alkali metal cation; with the proviso that the chain length of R1—On-L- is not greater than 6 atoms.
    Type: Grant
    Filed: June 23, 2011
    Date of Patent: August 27, 2013
    Assignee: E I du Pont de Nemours and Company
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal
  • Publication number: 20120116015
    Abstract: 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.
    Type: Application
    Filed: November 9, 2011
    Publication date: May 10, 2012
    Applicant: E. I. DU PONT DE NEMOURS AND COMPANY
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal, Dipti Dilip Khasnis
  • Publication number: 20120116003
    Abstract: 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.
    Type: Application
    Filed: November 9, 2011
    Publication date: May 10, 2012
    Applicant: E. I. DU PONT DE NEMOURS AND COMPANY
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal, Dipti Dilip Khasnis
  • Publication number: 20120116017
    Abstract: 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.
    Type: Application
    Filed: November 9, 2011
    Publication date: May 10, 2012
    Applicant: E. I. DU PONT DE NEMOURS AND COMPANY
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal, Dipti Dilip Khasnis
  • Publication number: 20120077931
    Abstract: 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: fluoropolyether acid or salt thereof having a number average molecular weight of at least about 800 g/mol; and fluorosurfactant having the formula: [R1—On-L-A?]Y+ wherein: R1 is a linear or branched partially or fully fluorinated aliphatic group which may contain ether linkages; n is 0 or 1; L is a linear or branched alkylene group which may be nonfluorinated, partially fluorinated or fully fluorinated and which may contain ether linkages; A? is an anionic group selected from the group consisting of carboxylate, sulfonate, sulfonamide anion, and phosphonate; and Y+ is hydrogen, ammonium or alkali metal cation; with the proviso that the chain length of R1—On-L- is not greater than 6 atoms.
    Type: Application
    Filed: December 7, 2011
    Publication date: March 29, 2012
    Applicant: E. I. DU PONT DE NEMOURS AND COMPANY
    Inventors: PAUL DOUGLAS BROTHERS, Subhash Vishnu Gangal
  • Publication number: 20120004365
    Abstract: 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.
    Type: Application
    Filed: September 13, 2011
    Publication date: January 5, 2012
    Applicant: E.I. DU PONT DE NEMOURS AND COMPANY
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal, Gregory Allen Chapman, Jon Lee Howell, Adam Paul Smith
  • Publication number: 20110251317
    Abstract: 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: fluoropolyether acid or salt thereof having a number average molecular weight of at least about 800 g/mol; and fluorosurfactant having the formula: [R1—On-L-A?]Y+ wherein: R1 is a linear or branched partially or fully fluorinated aliphatic group which may contain ether linkages; n is 0 or 1; L is a linear or branched alkylene group which may be nonfluorinated, partially fluorinated or fully fluorinated and which may contain ether linkages; A? is an anionic group selected from the group consisting of carboxylate, sulfonate, sulfonamide anion, and phosphonate; and Y+ is hydrogen, ammonium or alkali metal cation; with the proviso that the chain length of R1—On-L- is not greater than 6 atoms.
    Type: Application
    Filed: June 23, 2011
    Publication date: October 13, 2011
    Applicant: E. I. DU PONT DE NEMOURS AND COMPANY
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal
  • Patent number: 7977438
    Abstract: A process for polymerizing at least one fluorinated monomer in an aqueous polymerization medium in the presence of initiator and polymerization agent to form an aqueous dispersion of particles of fluoropolymer having a fluoropolymers solids content of at least about 10% by weight. The polymerization agent is a combination of fluoropolyether acid or salt thereof and siloxane surfactant. The aqueous polymerization medium contains less than about 300 ppm of perfluoroalkane carboxylic acid or salt fluorosurfactants.
    Type: Grant
    Filed: November 9, 2007
    Date of Patent: July 12, 2011
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal
  • Patent number: 7897682
    Abstract: A process for polymerizing at least one fluorinated monomer in an aqueous medium in the presence of initiator and polymerization agent to form an aqueous dispersion of particles of fluoropolymer having a fluoropolymers solids content of at least about 10% by weight. The polymerization agent is a combination of fluoropolyether acid or salt thereof and hydrocarbon surfactant. The aqueous medium contains less than about 300 ppm of perfluoroalkane carboxylic acid or salt fluorosurfactants. The process is preferably performed without adding polymer seed prior to polymerization kick-off.
    Type: Grant
    Filed: November 9, 2007
    Date of Patent: March 1, 2011
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal
  • Publication number: 20100152363
    Abstract: 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: fluoropolyether acid or salt thereof having a number average molecular weight of at least about 800 g/mol; and fluorosurfactant having the formula: [R1—On-L-A?]Y+ wherein: R1 is a linear or branched partially or fully fluorinated aliphatic group which may contain ether linkages; n is 0 or 1; L is a linear or branched alkylene group which may be nonfluorinated, partially fluorinated or fully fluorinated and which may contain ether linkages; A? is an anionic group selected from the group consisting of carboxylate, sulfonate, sulfonamide anion, and phosphonate; and Y+ is hydrogen, ammonium or alkali metal cation; with the proviso that the chain length of R1—On-L- is not greater than 6 atoms.
    Type: Application
    Filed: February 25, 2010
    Publication date: June 17, 2010
    Applicant: E.I. DU PONT DE NEMOURS AND COMPANY
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal
  • Publication number: 20100152379
    Abstract: 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: fluoropolyether acid or salt thereof having a number average molecular weight of at least about 800 g/mol; and fluorosurfactant having the formula: [R1—On-L-A?]Y+ wherein: R1 is a linear or branched partially or fully fluorinated aliphatic group which may contain ether linkages; n is 0 or 1; L is a linear or branched alkylene group which may be nonfluorinated, partially fluorinated or fully fluorinated and which may contain ether linkages; A? is an anionic group selected from the group consisting of carboxylate, sulfonate, sulfonamide anion, and phosphonate; and Y+ is hydrogen, ammonium or alkali metal cation; with the proviso that the chain length of R1—On-L- is not greater than 6 atoms.
    Type: Application
    Filed: February 25, 2010
    Publication date: June 17, 2010
    Applicant: E. I. DU PONT DE NEMOURS AND COMPANY
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal
  • Publication number: 20100152378
    Abstract: 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: fluoropolyether acid or salt thereof having a number average molecular weight of at least about 800 g/mol; and fluorosurfactant having the formula: [R1—On-L-A?]Y+ wherein: R1 is a linear or branched partially or fully fluorinated aliphatic group which may contain ether linkages; n is 0 or 1; L is a linear or branched alkylene group which may be nonfluorinated, partially fluorinated or fully fluorinated and which may contain ether linkages; A? is an anionic group selected from the group consisting of carboxylate, sulfonate, sulfonamide anion, and phosphonate; and Y+ is hydrogen, ammonium or alkali metal cation; with the proviso that the chain length of R1—On-L- is not greater than 6 atoms.
    Type: Application
    Filed: February 25, 2010
    Publication date: June 17, 2010
    Applicant: E. I. DU PONT DE NEMOURS AND COMPANY
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal
  • Patent number: 7705074
    Abstract: 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: fluoropolyether acid or salt thereof having a number average molecular weight of at least about 800 g/mol; and fluorosurfactant having the formula: [R1—On-L-A?] Y+ wherein: R1 is a linear or branched partially or fully fluorinated aliphatic group which may contain ether linkages; n is 0 or 1; L is a linear or branched alkylene group which may be nonfluorinated, partially fluorinated or fully fluorinated and which may contain ether linkages; A? is an anionic group selected from the group consisting of carboxylate, sulfonate, sulfonamide anion, and phosphonate; and Y+ is hydrogen, ammonium or alkali metal cation; with the proviso that the chain length of R1—On-L- is not greater than 6 atoms.
    Type: Grant
    Filed: November 9, 2007
    Date of Patent: April 27, 2010
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal
  • Publication number: 20090281241
    Abstract: 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.
    Type: Application
    Filed: May 6, 2009
    Publication date: November 12, 2009
    Applicant: E. I. DU PONT DE NEMOURS AND COMPANY
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal, Gregory Allen Chapman, Jon Lee Howell, Adam Paul Smith
  • Publication number: 20090281261
    Abstract: A process for making fluoropolymer resin comprising polymerizing at least one fluorinated monomer in an aqueous medium containing initiator and polymerization agent comprising fluoroether carboxylic acid or salt thereof to form an aqueous dispersion of particles of fluoropolymer. The fluoroether carboxylic acid or salt thereof employed in the process has the formula: [R1—O-L-COO?]Y+ wherein R1 is a linear, branched or cyclic partially or fully fluorinated aliphatic group which may contain ether linkages; L is a branched partially or fully fluorinated alkylene group which may contain ether linkages; and Y+ is hydrogen, ammonium or alkali metal cation. Wet fluoropolymer resin is isolated from the aqueous medium. The wet fluoropolymer resin is to produce a dry fluoropolymer resin and to decarboxylate the residual fluoroether carboxylic acid or salt to produce a vapor of fluoroether byproduct. The vapor of fluoroether byproduct is captured.
    Type: Application
    Filed: May 6, 2009
    Publication date: November 12, 2009
    Applicant: E. I. DU PONT DE NEMOURS AND COMPANY
    Inventors: Paul Douglas Brothers, Lam H. Leung, Subhash Vishnu Gangal
  • Publication number: 20080114121
    Abstract: A process for polymerizing at least one fluorinated monomer in an aqueous medium in the presence of initiator and polymerization agent to form an aqueous dispersion of particles of fluoropolymer having a fluoropolymers solids content of at least about 10% by weight. The polymerization agent is a combination of fluoropolyether acid or salt thereof and hydrocarbon surfactant. The aqueous medium contains less than about 300 ppm of perfluoroalkane carboxylic acid or salt fluorosurfactants. The process is preferably performed without adding polymer seed prior to polymerization kick-off.
    Type: Application
    Filed: November 9, 2007
    Publication date: May 15, 2008
    Applicant: E. I. DU PONT DE NEMOURS AND COMPANY
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal
  • Publication number: 20080114143
    Abstract: A process for polymerizing at least one fluorinated monomer in an aqueous polymerization medium in the presence of initiator and polymerization agent to form an aqueous dispersion of particles of fluoropolymer having a fluoropolymers solids content of at least about 10% by weight. The polymerization agent is a combination of fluoropolyether acid or salt thereof and siloxane surfactant. The aqueous polymerization medium contains less than about 300 ppm of perfluoroalkane carboxylic acid or salt fluorosurfactants.
    Type: Application
    Filed: November 9, 2007
    Publication date: May 15, 2008
    Applicant: E. I. DU PONT DE NEMOURS AND COMPANY
    Inventors: Paul Douglas Brothers, Subhash Vishnu Gangal
  • Patent number: 3980612
    Abstract: The agglomeration of finely-divided granular tetrafluoroethylene polymer particles to produce agglomerated particles having improved flow properties is carried out by agitating the finely-divided particles in an aqueous dispersion containing a substantially water-immiscible organic liquid. The finely-divided particles can first be blended with particulate metal filler material and the blend agglomerated. The presence of a small amount of an aqueous dispersion of polytetrafluoroethylene prepared by the aqueous dispersion method, while agitating the aqueous dispersion of the blend of the filler material and the finely-divided tetrafluoroethylene polymer, effectively reduces loss of filler during the agglomeration procedure.
    Type: Grant
    Filed: April 11, 1975
    Date of Patent: September 14, 1976
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Subhash Vishnu Gangal