Patents by Inventor David L. Tabb

David L. Tabb 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: 6221971
    Abstract: Elastomeric vinylidene fluoride-containing copolymers are cured by a sequential process. In a first step, gum fluoroelastomer is mixed at a temperature of 150° C.-250° C. in the presence of an organic base and metal oxide or metal hydroxide to generate an unsaturated product. The unsaturated product is mixed with a polyhydroxy compound, polyamine, or organic peroxide and the resultant compounded fluoroelastomer is crosslinked.
    Type: Grant
    Filed: November 18, 1999
    Date of Patent: April 24, 2001
    Assignee: DuPont Dow Elastomers, L.L.C.
    Inventor: David L. Tabb
  • Patent number: 6020440
    Abstract: Elastomeric vinylidene fluoride-containing copolymers are cured by a sequential process. In a first step, gum fluoroelastomer is mixed at a temperature of 150.degree. C.-250.degree. C. in the presence of an organic base and metal oxide or metal hydroxide to generate an unsaturated product. The unsaturated product is mixed with a polyhydroxy compound, polyamine, or organic peroxide and the resultant compounded fluoroelastomer is crosslinked.
    Type: Grant
    Filed: September 29, 1997
    Date of Patent: February 1, 2000
    Assignee: Dupont Dow Elastomers, L.L.C.
    Inventor: David L. Tabb
  • Patent number: 5578681
    Abstract: Curable elastomeric blends of fluoroelastomer and ethylene copolymer elastomer in which at least one of the fluoroelastomer and ethylene copolymer elastomer contains a cure site monomer.
    Type: Grant
    Filed: April 3, 1995
    Date of Patent: November 26, 1996
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: David L. Tabb
  • Patent number: 5548028
    Abstract: Blends of previously-vulcanized fluoroelastomer with fluorine-free elastomer can be cured to have unexpectedly excellent physical properties.
    Type: Grant
    Filed: February 24, 1995
    Date of Patent: August 20, 1996
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: David L. Tabb
  • Patent number: 5412034
    Abstract: Curable elastomeric blends of fluoroelastomer and hydrocarbon elastomer in which at least one of the fluoroelastomer and hydrocarbon elastomer contains a cure site monomer.
    Type: Grant
    Filed: October 26, 1993
    Date of Patent: May 2, 1995
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: David L. Tabb
  • Patent number: 4925892
    Abstract: A fluoroelastomer composition that has enhanced adhesion to metal when cured which comprises:(a) an elastomeric copolymer of vinylidene fluoride and at least one other fluorinated monomer,(b) a vulcanization accelerator that is a quaternary phosphonium compound,(c) a crosslinking agent selected from the group consisting of a bisphenol or a polyhydroxy phenol of the formula: ##STR1## where R is H or an alkyl group or an aryl group and R' is an alkyl group or an aryl group, and(d) 0.02-0.8 weight percent based on the weight of the elastomeric copolymer of a metal adhesion promoter that is a tetraalkylammonium halide where each alkyl group contains 1-10 carbon atoms and the halide is a chloride, bromide or iodide. When cured in contact with metal the fluoroelastomer composition forms a strong bond with the metal surface.
    Type: Grant
    Filed: June 19, 1989
    Date of Patent: May 15, 1990
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: David L. Tabb, Janet M. Wilson
  • Patent number: 4868234
    Abstract: A fluoroelastomer composition that has enhanced adhesion to metal when cured which comprises:(a) an elastomeric copolymer of vinylidene fluoride and at least one other fluorinated monomer,(b) a vulcanization accelerator that is a quaternary phosphonium compound,(c) a crosslinking agent selected from the group consisting of a bisphenol or a polyhydroxy phenol of the formula: ##STR1## where R is H or an alkyl group or an aryl group and R' is an alkyl group or an aryl group, and(d) 0.02-0.8 weight percent based on the weight of the elastomeric copolymer of a metal adhesion promoter that is a tetraalkylammonium halide where each alkyl group contains 1-10 carbon atoms and the halide is a chloride, bromide or iodide. When cured in contact with metal the fluoroelastomer composition forms a strong bond with the metal surface.
    Type: Grant
    Filed: April 27, 1988
    Date of Patent: September 19, 1989
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: David L. Tabb, Janet M. Wilson
  • Patent number: 4708988
    Abstract: An extrudable fluoroelastomer comprising a gelled fluoroelastomer having units of vinylidene fluoride and units of at least one other fluorine-containing monomer copolymerizable with vinylidene fluoride, said monomer containing from 2-7 carbon atoms, containing no bromine atoms and containing at least as many flourine atoms as carbon atoms, said fluoroelastomer having been simultaneously mixed, sheared and gelled by an organic peroxide gelling agent to a gel content of from about 15-80% by weight, measured in methyl ethyl ketone at 80.degree. C.
    Type: Grant
    Filed: July 1, 1985
    Date of Patent: November 24, 1987
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: David L. Tabb
  • Patent number: 4440724
    Abstract: A composition, test means, method of making test means and process for the detection of ketone bodies in human fluids. The composition includes a chromogen and, discrete therefrom, a combination of a metal salt, a primary amine and a chelator for the metal. The composition may be in tablet form or in separately sequentially impregnated layers on a carrier. If the composition is in tablet form, the composition is a dry combination of the chromogen, the metal salt, primary amine acid and the chelator. If the test means is formed on a carrier as separately impregnated layers, the chromogen is impregnated onto the carrier, the impregnated carrier is then dried, and then the combination of the primary amine, metal salt and chelator in liquid form are impregnated over the dry chromogen and thereafter the impregnated carrier is dried.
    Type: Grant
    Filed: November 1, 1982
    Date of Patent: April 3, 1984
    Assignee: Helena Laboratories Corporation
    Inventors: David L. Tabb, Janine P. Burrows
  • Patent number: 4405718
    Abstract: A urobilinogen control standard composition, control standard device and a method for preparing such composition are disclosed. The composition comprises a substituted indole:nonionic detergent solution which is reactive with p-diethylaminobenzaldehyde and hydrochloric acid. The composition is produced by dissolving the substituted indole in a selected nonionic detergent and diluting the solution to a predetermined level. The device is a carrier matrix impregnated with a solution of a substituted indole and a nonionic detergent.
    Type: Grant
    Filed: July 20, 1981
    Date of Patent: September 20, 1983
    Assignee: Miles Laboratories, Inc.
    Inventors: Myron C. Rapkin, David L. Tabb
  • Patent number: 4380585
    Abstract: An improved composition, device and method, whereby enhanced sensitivity is achieved in detecting test sample constituents such as glucose and blood. The improvement resides in the use of a broad range of compounds as enhancers for benzidine-type indicators. The enhancer tends to stabilize the blue colorform of such indicators.
    Type: Grant
    Filed: July 23, 1981
    Date of Patent: April 19, 1983
    Assignee: Miles Laboratories, Inc.
    Inventors: Thomas A. Magers, David L. Tabb
  • Patent number: 4362697
    Abstract: A test device for performing homogeneous specific binding assays is composed of a carrier matrix having incorporated therein reagents and an enhancer substance. The enhancer substance is a copolymer of vinyl pyrrolidone and a type of acrylic comonomer.
    Type: Grant
    Filed: April 20, 1981
    Date of Patent: December 7, 1982
    Assignee: Miles Laboratories, Inc.
    Inventors: David L. Tabb, Richard J. Tyhach
  • Patent number: 4340393
    Abstract: An improved composition, device and method, whereby enhanced sensitivity is achieved in detecting test sample constituents such as glucose and blood. The improvement resides in the use of a broad range of compounds as enhancers for benzidine-type indicators. The enhancer tends to stabilize the blue colorform of such indicators.
    Type: Grant
    Filed: July 23, 1981
    Date of Patent: July 20, 1982
    Assignee: Miles Laboratories, Inc.
    Inventors: Thomas A. Magers, David L. Tabb
  • Patent number: 4340392
    Abstract: An improved composition, device and method, whereby enhanced sensitivity is achieved in detecting test sample constituents such as glucose and blood. The improvement resides in the use of a broad range of compounds as enhancers for benzidine-type indicators. The enhancer tends to stabilize the blue colorform of such indicators.
    Type: Grant
    Filed: July 23, 1981
    Date of Patent: July 20, 1982
    Assignee: Miles Laboratories, Inc.
    Inventors: Thomas A. Magers, David L. Tabb
  • Patent number: 4340395
    Abstract: An improved composition, device and method, whereby enhanced sensitivity is achieved in detecting test sample constituents such as glucose and blood. The improvement resides in the use of a broad range of compounds as enhancers for benzidine-type indicators. The enhancer tends to stabilize the blue colorform of such indicators.
    Type: Grant
    Filed: July 23, 1981
    Date of Patent: July 20, 1982
    Assignee: Miles Laboratories, Inc.
    Inventors: Thomas A. Magers, David L. Tabb
  • Patent number: 4340394
    Abstract: An improved composition, device and method, whereby enhanced sensitivity is achieved in detecting test sample constituents such as glucose and blood. The improvement resides in the use of a broad range of compounds as enhancers for benzidine-type indicators. The enhancer tends to stabilize the blue colorform of such indicators.
    Type: Grant
    Filed: July 23, 1981
    Date of Patent: July 20, 1982
    Assignee: Miles Laboratories, Inc.
    Inventors: Thomas A. Magers, David L. Tabb
  • Patent number: 4339242
    Abstract: An improved composition, device and method, whereby enhanced sensitivity is achieved in detecting test sample constituents such as glucose and blood. The improvement resides in the use of a broad range of compounds as enhancers for benzidine-type indicators. The enhancer tends to stabilize the blue color form of such indicators.
    Type: Grant
    Filed: July 23, 1981
    Date of Patent: July 13, 1982
    Assignee: Miles Laboratories, Inc.
    Inventors: Thomas A. Magers, David L. Tabb
  • Patent number: 4339243
    Abstract: An improved composition, device and method, whereby enhanced sensitivity is achieved in detecting test sample constituents such as glucose and blood. The improvement resides in the use of a broad range of compounds as enhancers for benzidine-type indicators. The enhancer tends to stabilize the blue colorform of such indicators.
    Type: Grant
    Filed: July 23, 1981
    Date of Patent: July 13, 1982
    Assignee: Miles Laboratories, Inc.
    Inventors: Thomas A. Magers, David L. Tabb
  • Patent number: 4318984
    Abstract: An improved composition, test device and method for detecting the presence of a sugar in a test sample are disclosed. The composition comprises a sugar oxidase, a peroxidase, a chromogen compound capable of producing a detectable response in the presence of hydrogen peroxide and peroxidase, and an enhancer compound having the structure ##STR1## in which the R substituents, same or different, are hydrogen, lower alkyl, lower alkyloxy, aryl or aryloxy; or in which two of the R substituents bound to a common atom together form a closed ring having 3 to about 6 atoms, said ring being saturated, unsaturated or aromatic. R' is hydrogen or an alkyl or alkenyl group having 1 to about 20 carbon atoms. The composition can be incorporated with a carrier matrix to form a test device. The method comprises contacting a test solution with the device and observing any detectable response.
    Type: Grant
    Filed: November 13, 1979
    Date of Patent: March 9, 1982
    Assignee: Miles Laboratories, Inc.
    Inventors: Thomas A. Magers, David L. Tabb
  • Patent number: 4301115
    Abstract: A test device for detecting the presence of constituents in a liquid test sample, and method for preparing it are disclosed. The device comprises a base support member coated with a hydrophobic barrier layer onto which is affixed a plurality of spaced apart reagents respectively responsive to different constituents of the test sample. The barrier layer comprises finely divided silica particles, to the surface of which are randomly covalently bound groups having the structure--O--SiR.sub.3wherein the R substituents, same or different, are hydrogen, lower alkyl or aryl.
    Type: Grant
    Filed: June 22, 1979
    Date of Patent: November 17, 1981
    Assignee: Miles Laboratories, Inc.
    Inventors: Myron C. Rapkin, David L. Tabb