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: 6228979Abstract: 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: GrantFiled: December 13, 1999Date of Patent: May 8, 2001Assignee: E. I. du Pont de Nemours and CompanyInventors: Neville E. Drysdale, Mike Fryd, Sapé Quashie
-
Patent number: 6020499Abstract: 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: GrantFiled: June 5, 1998Date of Patent: February 1, 2000Assignee: E. I. du Pont Nemours and CompanyInventors: Neville E. Drysdale, Mike Fryd, Sape Quashie
-
Patent number: 5635585Abstract: 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: GrantFiled: April 19, 1995Date of Patent: June 3, 1997Assignee: E. I. Du Pont de Nemours and CompanyInventors: Neville E. Drysdale, Joel D. Citron
-
Patent number: 5541346Abstract: 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: GrantFiled: April 19, 1995Date of Patent: July 30, 1996Assignee: E. I. Du Pont de Nemours and CompanyInventors: Neville E. Drysdale, Norman Herron
-
Patent number: 5478920Abstract: 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: GrantFiled: July 16, 1993Date of Patent: December 26, 1995Assignee: E. I. Du Pont de Nemours and CompanyInventor: Neville E. Drysdale
-
Patent number: 5475069Abstract: 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: GrantFiled: October 31, 1994Date of Patent: December 12, 1995Assignee: E. I. Du Pont de Nemours and CompanyInventor: Neville E. Drysdale
-
Patent number: 5430122Abstract: 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: GrantFiled: February 17, 1994Date of Patent: July 4, 1995Assignee: E. I. Du Pont de Nemours and CompanyInventor: Neville E. Drysdale
-
Patent number: 5288881Abstract: 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: GrantFiled: March 12, 1992Date of Patent: February 22, 1994Assignee: E. I. du Pont de Nemours and CompanyInventors: Neville E. Drysdale, Kang Lin, Thomas W. Stambaugh
-
Patent number: 5236560Abstract: 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: GrantFiled: March 13, 1992Date of Patent: August 17, 1993Assignee: E. I. Du Pont de Nemours and CompanyInventors: Neville E. Drysdale, Thomas W. Stambaugh, James V. Tarbell
-
Patent number: 5235031Abstract: 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: GrantFiled: March 13, 1992Date of Patent: August 10, 1993Assignee: E. I. Du Pont de Nemours and CompanyInventors: Neville E. Drysdale, Thomas M. Ford, Stephan J. McLain
-
Patent number: 5117008Abstract: 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: GrantFiled: October 23, 1990Date of Patent: May 26, 1992Assignee: E. I. Du Pont de Nemours and CompanyInventors: Kamlesh K. Bhatia, Neville E. Drysdale, John R. Kosak
-
Patent number: 5095098Abstract: 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: GrantFiled: April 3, 1991Date of Patent: March 10, 1992Assignee: E. I. Du Pont de Nemours and CompanyInventors: Stephan J. McLain, Neville E. Drysdale
-
Patent number: 5028667Abstract: 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: GrantFiled: September 29, 1989Date of Patent: July 2, 1991Assignee: E.I. Du Pont de Nemours and CompanyInventors: Stephan J. McLain, Neville E. Drysdale
-
Patent number: 4952291Abstract: 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: GrantFiled: December 6, 1989Date of Patent: August 28, 1990Assignee: E. I. Du Pont de Nemours and CompanyInventors: Neville E. Drysdale, Frederick W. Mader, Rudolf E. Svadlenak
-
Patent number: 4824995Abstract: 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: GrantFiled: May 9, 1988Date of Patent: April 25, 1989Assignee: E. I. Du Pont de Nemours and CompanyInventor: Neville E. Drysdale