Patents by Inventor Neville E. Drysdale

Neville E. Drysdale 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: 6228979
    Abstract: Six-membered cyclic carbonates (2-oxo-1,3-ioxanes) in which keto or carbohydrocarbyloxy groups are bound to the 5 position of the ring are disclosed. They react surprising quickly with primary or secondary cyclic amines, and the novel product hydroxyurethanes are usefull as reactive diluents.
    Type: Grant
    Filed: December 13, 1999
    Date of Patent: May 8, 2001
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Neville E. Drysdale, Mike Fryd, Sapé Quashie
  • Patent number: 6020499
    Abstract: Six-membered cyclic carbonates (2-oxo-1,3-dioxanes) in which keto or carbohydrocarbyloxy groups are bound to the 5 position of the ring are disclosed. They react surprising quickly with primary or secondary cyclic amines, and the novel product hydroxyurethanes are useful as reactive diluents.
    Type: Grant
    Filed: June 5, 1998
    Date of Patent: February 1, 2000
    Assignee: E. I. du Pont Nemours and Company
    Inventors: Neville E. Drysdale, Mike Fryd, Sape Quashie
  • Patent number: 5635585
    Abstract: A process for polymerizing oxiranes, oxetanes, oxepanes, dioxolanes, trioxanes, and tetrahydrofurans to their respective polymers by contacting them with a selected metal compound is disclosed; and also a process for depolymerizing polytetrahydrofurans to monomeric tetrahydrofurans by contacting the polymer with a selected metal compound at a temperature of about 100.degree. C. to about 250.degree. C. The catalysts may be in solution of part of a heterogeneous solid, and selected organic compounds are used as accelerators in the polymerizations. The polymeric products, some of which are novel, may be used as polyether monomers for further polymerization, as by reaction with isocyanates to produce polyurethanes, and other useful polymers. Some of the polymeric products are relatively high in molecular weight and are suitable for direct use, for instance as spandex fibers.
    Type: Grant
    Filed: April 19, 1995
    Date of Patent: June 3, 1997
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Neville E. Drysdale, Joel D. Citron
  • Patent number: 5541346
    Abstract: A process for polymerizing oxiranes, oxetanes, oxepanes, dioxolanes, trioxanes, and tetrahydrofurans to their respective polymers by contacting them with a selected metal compound is disclosed; and also a process for depolymerizing polytetrahydrofurans to monomeric tetrahydrofurans by contacting the polymer with a selected metal compound at a temperature of about 100.degree. C. to about 250.degree. C. The catalysts may be in solution or part of a heterogeneous solid, and selected organic compounds are used as accelerators in the polymerizations. The polymeric products, some of which are novel, may be used as polyether monomers for further polymerization, as by reaction with isocyanates to produce polyurethanes, and other useful polymers. Some of the polymeric products are relatively high in molecular weight and are suitable for direct use, for instance as spandex fibers.
    Type: Grant
    Filed: April 19, 1995
    Date of Patent: July 30, 1996
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Neville E. Drysdale, Norman Herron
  • Patent number: 5478920
    Abstract: When selected silicon compounds are added to cationic polymerizations of cyclic ethers such as oxiranes and tetrahydrofurans, the rate of polymerization is often increased, and novel polyethers are produced. The polyether products are useful as monomers and macromonomers, particularly after hydrolysis of silicon containing end groups.
    Type: Grant
    Filed: July 16, 1993
    Date of Patent: December 26, 1995
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Neville E. Drysdale
  • Patent number: 5475069
    Abstract: Process for the polymerization of selected vinyl ethers catalyzed by yttrium or rare earth metal perfluoroalkylsulfonates. A preferred perfluoroalkylsulfonate anion is triflate (trifluoromethanesulfonate). The resulting polymers are useful as tackifiers in adhesives as well as in other uses (e.g., plasticizers, viscosity modifiers).
    Type: Grant
    Filed: October 31, 1994
    Date of Patent: December 12, 1995
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Neville E. Drysdale
  • Patent number: 5430122
    Abstract: Poly(ether-urethanes) can be made from cyclic ethers and organic isocyanates by using selected metal compounds as catalysts. Polymers useful as thermoplastic elastomers, spandex fibers or urethane rubbers can be made by reacting diisocyanates containing functional groups with a tetrahydrofuran, especially tetrahydrofuran itself.
    Type: Grant
    Filed: February 17, 1994
    Date of Patent: July 4, 1995
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Neville E. Drysdale
  • Patent number: 5288881
    Abstract: An improved process for converting oligomers of alphahydroxycarboxylic acids, such as glycolic and lactic acid, to dimeric cyclic esters, such as glycolide and lactide. The continuous process is conducted at reduced pressures and depolymerizing temperatures in a heated columnar depolymerization zone, coupled with an essentially unheated receiver for unconverted oligomer. By feeding the oligomer to the upper end of the column while coordinating the feed rate with the depolymerization temperature such that a fraction of the oligomer is converted to a vapor product stream containing the cyclic ester and another fraction of the oligomer exits the column at its lower end and passes to the receiver vessel, the dimeric cyclic ester is produced at high production rates and the oligomer is subjected to minimal thermal stress.
    Type: Grant
    Filed: March 12, 1992
    Date of Patent: February 22, 1994
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Neville E. Drysdale, Kang Lin, Thomas W. Stambaugh
  • Patent number: 5236560
    Abstract: A dimeric cyclic ester of an alpha-hydroxycarboxylic acid (lactide) is separated and recovered from a vapor product stream containing the cyclic ester, the corresponding lower-boiling hydroxycarboxylic acid (lactic), higher-boiling oligomeric hydroxycarboxylic acid and water without the use of solvents. More specifically, the vapor stream is condensed to obtain a condensate containing substantially all the cyclic ester, and the condensate is refined by distillation means alone to recover the cyclic ester substantially free of water, the alpha-hydroxycarboxylic acid and the higher-boiling oligomers.
    Type: Grant
    Filed: March 13, 1992
    Date of Patent: August 17, 1993
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Neville E. Drysdale, Thomas W. Stambaugh, James V. Tarbell
  • Patent number: 5235031
    Abstract: A process for polymerizing lactide and up to 20 mole percent of another lactone in the absence of solvent at 100.degree. to 220.degree. C. using an yttrium or lanthanide series rare earth metal catalyst.
    Type: Grant
    Filed: March 13, 1992
    Date of Patent: August 10, 1993
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Neville E. Drysdale, Thomas M. Ford, Stephan J. McLain
  • Patent number: 5117008
    Abstract: An improved process for the recovery of lactide or other dimeric cyclic ester from a gas stream containing the cyclic ester and such hydroxylic impurities as water and open-chain hydroxycarboxylic acids by scrubbing the gas stream with a nonpolar water-immiscible solvent at a temperature at which the cyclic ester is removed from the solvent and any water present in the gas stream is vaporized from the solvent. The cyclic ester is recovered from the solvent in a high state of optical purity.
    Type: Grant
    Filed: October 23, 1990
    Date of Patent: May 26, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Kamlesh K. Bhatia, Neville E. Drysdale, John R. Kosak
  • Patent number: 5095098
    Abstract: Process for yttrium and rare earth compound catalyzed polymerization of lactones and the living polymer compositions of such polymerizations, novel polyester products of such polymerizations and novel yttrium and rare earth metal compounds useful as catalysts in the polymerization of biodegradable polymers for medical uses and flexible films for packaging.
    Type: Grant
    Filed: April 3, 1991
    Date of Patent: March 10, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Stephan J. McLain, Neville E. Drysdale
  • Patent number: 5028667
    Abstract: Process for yttrium and rare earth compound catalyzed polymerization of lactones and the living polymer compositions of such polymerizations, novel polyester products of such polymerizations and novel yttrium and rare earth metal compounds useful as catalysts in the polymerization of biodegradable polymers for medical uses and flexible films for packaging.
    Type: Grant
    Filed: September 29, 1989
    Date of Patent: July 2, 1991
    Assignee: E.I. Du Pont de Nemours and Company
    Inventors: Stephan J. McLain, Neville E. Drysdale
  • Patent number: 4952291
    Abstract: An aldehyde in a mixture containing hemiacetals and hydrates of the aldehyde is purified by treating the mixture with an effective amount of microwave radiation to decompose the hemiacetals and hydrates. Liberated water and/or alcohol is immediately removed with an adsorbent.
    Type: Grant
    Filed: December 6, 1989
    Date of Patent: August 28, 1990
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Neville E. Drysdale, Frederick W. Mader, Rudolf E. Svadlenak
  • Patent number: 4824995
    Abstract: A poly-p-phenylamino carboxylate having the following structure: ##STR1## wherein n is greater than 1; R is a C.sub.1 to C.sub.6 alkyl group; and R.sub.1 and R.sub.
    Type: Grant
    Filed: May 9, 1988
    Date of Patent: April 25, 1989
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Neville E. Drysdale