Patents by Inventor Dwight K. Hoffman

Dwight K. Hoffman 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: 6613816
    Abstract: In one embodiment the invention is An adhesive composition comprising a) a polymer having a flexible backbone and a reactive moiety capable of cross-linking, b) a particle comprising an active agent encapsulated in an encapsulating agent wherein the active agent comprises a catalyst for cross-linking of the reactive moiety, a curing agent for the reactive moiety, an accelerator for the curing reaction or a mixture thereof; and the encapsulating agent comprises a side chain crystallizable polymer wherein the active agent is not substantially extractable from the particle at ambient conditions in a first extraction after particle formation.
    Type: Grant
    Filed: June 7, 2001
    Date of Patent: September 2, 2003
    Assignee: The Dow Chemical Company
    Inventors: Syed Z. Mahdi, Renhe R. Lin, Dwight K. Hoffman, Gordon M. Parker, Harry W. Hsieh
  • Patent number: 6355127
    Abstract: In one embodiment the invention is An adhesive composition comprising a) a polymer having a flexible backbone and a reactive moiety capable of cross-linking, b) a particle comprising an active agent encapsulated in an encapsulating agent wherein the active agent comprises a catalyst for cross-linking of the reactive moiety, a curing agent for the reactive moiety, an accelerator for the curing reaction or a mixture thereof; and the encapsulating agent comprises a side chain crystallizable polymer wherein the active agent is not substantially extractable from the particle at ambient conditions in a first extraction after particle formation. This composition is used in binding two subtracters together.
    Type: Grant
    Filed: April 27, 1999
    Date of Patent: March 12, 2002
    Assignees: The Dow Chemical Company, Essex Specialty Products, Inc.
    Inventors: Syed Z. Mahdi, Renhe R. Lin, Dwight K. Hoffman, Gordon M. Parker, by Michael Parker, Harry W. Hsieh
  • Publication number: 20020010272
    Abstract: In one embodiment the invention is An adhesive composition comprising
    Type: Application
    Filed: June 7, 2001
    Publication date: January 24, 2002
    Inventors: Syed Z. Mahdi, Renhe R. Lin, Dwight K. Hoffman, Gordon M. Parker, Harry W. Hsieh, Michael Parker
  • Patent number: 6277903
    Abstract: The invention is a sprayable coating having noise vibration and harshness reduction or absorption properties. Such composition comprises from about 10 to about 60 percent of the flexible epoxy resin, from about 5 to about 40 percent by weight of a rigid epoxy resin formulation, and a curing agent for the epoxy moieties of the two resins. In another embodiment, the invention is a method of coating a substrate to reduce the impact of noise vibration and harshness on the substrate or users of the substrate, which process comprises spraying the above defined composition on to a substrate and curing the resin on such substrate. In yet another embodiment the invention is a coated substrate described herein before having enhanced noise vibration and harshness properties.
    Type: Grant
    Filed: September 21, 1998
    Date of Patent: August 21, 2001
    Assignees: The Dow Chemical Company, Essex Specialty Products, Inc.
    Inventors: Daniel P. Sophiea, Dwight K. Hoffman, Xiao Hong, Gloria Hsu
  • Patent number: 6224793
    Abstract: The invention is an encapsulated active agent comprising an active agent encapsulated in a crystallizable or thermoplastic polymer wherein the particle size of the encapsulated active agent is 3,000 microns or less wherein the active agent is not significantly extractable from the particles under ambient conditions. In another embodiment the invention is a process for preparing an encapsulated agent which comprises a) contacting an active agent with a crystallizable or thermoplastic polymer wherein the polymer is molten and the active agent in not volatile under the contacting conditions; b) forming particles of about 3000 microns or less; and c) exposing the particles to conditions such that the portion of the particle at and near the surface undergoes rapid solidification. The encapsulated active agents of the invention do not require washing in order for them to be stable in curable compositions. These encapsulated active agents can be designed to release the active agent at a desired temperature.
    Type: Grant
    Filed: April 27, 1999
    Date of Patent: May 1, 2001
    Assignees: The Dow Chemical Company, Landec Corporation
    Inventors: Dwight K. Hoffman, Steven P. Bitler
  • Patent number: 6133398
    Abstract: The present invention is a one-part adhesive composition comprising:A) an isocyanate functional polyurethane prepolymer;B) a catalyst capable of catalyzing the reaction of isocyanate moieties with an isocyanate reactive compound;C) particles comprising a curing agent for an isocyanate functional. polyurethane prepolymer encapsulated within a coating material;wherein the prepolymer has a free isocyanate content of from about 0.8 to about 2.2 percent. In another embodiment the invention is a process for bonding two substrates together which comprises rupturing the encapsulated curing agent particles so as to contact the curing agent with the prepolymer in the adhesive composition, contacting the adhesive composition of the invention with at least one of the substrates and contacting the substrates together along the portion of the substrate(s) to which the adhesive has been applied before the adhesive applied cures and allowing the adhesive to cure and bond the substrates together.
    Type: Grant
    Filed: April 13, 1999
    Date of Patent: October 17, 2000
    Assignee: The Dow Chemical Company
    Inventors: Shailesh S. Bhat, Sidky D. Rizk, Dwight K. Hoffman
  • Patent number: 5601761
    Abstract: An active material encapsulated in a coating material immiscible therewith is contacted with a solvent that dissolves residual active material on the surface of the coating material without dissolving the coating material. The resultant encapsulated material has improved stability as compared to the material not contacted with solvent.
    Type: Grant
    Filed: September 26, 1994
    Date of Patent: February 11, 1997
    Assignee: The Dow Chemical Company
    Inventors: Dwight K. Hoffman, David V. Dellar, Herman W. Schlameus
  • Patent number: 5461106
    Abstract: A solid polymeric latent initiator which is a dehydrated aqueous emulsion polymer of a monomer having an ethylenically unsaturated group and an organic salt group, the salt group being a product of an acid and a base, wherein either the acid or the base or the acid and the base are initiators capable of opening a strained heterocyclic ring system, provides rapid cure-on-demand one-part adhesives with improved shelf stability.
    Type: Grant
    Filed: December 12, 1994
    Date of Patent: October 24, 1995
    Assignee: The Dow Chemical Company
    Inventors: Gary L. Jialanella, Dwight K. Hoffman
  • Patent number: 5204386
    Abstract: A thixoropic adhesive composition exhibiing good sag resistance is prepared comprising a mixture of a polymer-modified epoxy resin and a rheological control agent. The polymer-modified epoxy resin is preferably a dispersion of acrylic elastomer in an epoxy resin in which the acrylic elastomer particles have added hydroxyl functionality which interacts favorably with rheological control agents, such as fumed silica. Acrylic epoxy resin dispersions containing added hydroxyl functionality give improved rheological control.
    Type: Grant
    Filed: June 9, 1992
    Date of Patent: April 20, 1993
    Assignee: The Dow Chemical Company
    Inventors: Yasemin Ersun-Hallsby, Dwight K. Hoffman, Gerald C. Kolb, Gene D. Rose
  • Patent number: 5055532
    Abstract: Vinylized epoxy resins, such as vinyl ester resins, comprise polymerizable ethylenic unsaturation and an in situ polymerized polymer, such as a polyalkyl acrylate. The vinylized epoxy resins can form stable dispersions and are useful in thermoset applications.
    Type: Grant
    Filed: July 6, 1987
    Date of Patent: October 8, 1991
    Assignee: The Dow Chemical Company
    Inventors: Dwight K. Hoffman, Virginia B. Messick, Michael G. Stevens
  • Patent number: 4798877
    Abstract: Novel radiation-curable, water-compatible, resinous compositions result from (1) terminally unsaturated molecules which are the esters of an epoxy compound and (2) the reaction product of a glycidyl ether and an unsaturated acid having at least one glycidyl group per molecule converted to an onium salt of a quaternary ammonium or amine salt, with the anion of an inorganic or organic acid.
    Type: Grant
    Filed: April 8, 1985
    Date of Patent: January 17, 1989
    Assignee: The Dow Chemical Company
    Inventors: Dwight K. Hoffman, Robert F. Harris, Richard A. Hickner
  • Patent number: 4789712
    Abstract: Dispersions of polymers and optional dispersion stabilizers in a polyepoxide resin continuous phase is characterized in that the dispersion remains stable above 60.degree. C. The compositions are curable and are useful as coatings, in preparing laminates and reinforced plastics, and as adhesives. The compositions exhibit properties which are superior to compositions containing reactive liquid polymers.
    Type: Grant
    Filed: August 10, 1987
    Date of Patent: December 6, 1988
    Assignee: The Dow Chemical Company
    Inventors: Dwight K. Hoffman, Charles B. Arends
  • Patent number: 4745153
    Abstract: This invention is a process for preparing a polymer polyol comprising the steps of(a) forming in a first step a dispersant by homopolymerizing a vinyl-terminated adduct, or copolymerizing said adduct with an ethylenically unsaturated monomer or mixture thereof which is not a vinyl-terminated adduct, in the presence of an active hydrogen-containing compound as a solvent under conditions such that the resulting dispersant is soluble in a base polyol, and has a Brookfield viscosity of less than about 25,000 centipoises as a 20-35 wt. -% solution in an active hydrogen-containing compound, and(b) polymerizing an ethylenically unsaturated monomer or mixture thereof in the presence of said dispersant and a base polyol under conditions such that the polymerized monomer forms a plurality and particles which are stabilized against agglomeration by the dispersant.
    Type: Grant
    Filed: December 17, 1986
    Date of Patent: May 17, 1988
    Assignee: The Dow Chemical Company
    Inventor: Dwight K. Hoffman
  • Patent number: 4708996
    Abstract: Dispersions of polymers and optional dispersion stabilizers in a polyepoxide resin continuous phase is characterized in that the dispersion remains stable above 60.degree. C. The compositions are curable and are useful as coatings, in preparing laminates and reinforced plastics, and as adhesives. The compositions exhibit properties which are superior to compositions containing reactive liquid polymers.
    Type: Grant
    Filed: October 25, 1984
    Date of Patent: November 24, 1987
    Assignee: The Dow Chemical Company
    Inventors: Dwight K. Hoffman, Charles B. Arends
  • Patent number: 4707529
    Abstract: Dispersions of siloxane polymers and optional dispersion stabilizers in a polyepoxide resin continuous phase are characterized in that the siloxane polymer is grafted to the polyepoxide resin, and the dispersions remain stable. The compositions are curable and are useful as coatings, in preparing laminates and reinforced plastics, and as adhesives.
    Type: Grant
    Filed: June 27, 1985
    Date of Patent: November 17, 1987
    Assignee: The Dow Chemical Company
    Inventors: Dwight K. Hoffman, Reet T. Fernandez
  • Patent number: 4690988
    Abstract: Vinylized epoxy resins, such as vinyl ester resins, comprise polymerizable ethylenic unsaturation and an in situ polymerized polymer, such as a polyalkyl acrylate. The vinylized epoxy resins can form stable dispersions and are useful in thermoset applications.
    Type: Grant
    Filed: January 22, 1985
    Date of Patent: September 1, 1987
    Assignee: The Dow Chemical Company
    Inventors: Dwight K. Hoffman, Michael G. Stevens, Virginia B. Messick
  • Patent number: 4640935
    Abstract: An adduct of a heteroatomic monomer, e.g., gamma-methacryloxypropyl trimethoxysilane and a monoahl, e.g., a monohydroxyl polyalkylene oxide or a polyahl, e.g., a polypropylene glycol, is usefully employed in the preparation of stable copolymer dispersions of the type used in the production of polyurethane foams and polyurethane elastomers.The copolymer dispersion is prepared by addition copolymerization of (1) the adduct with (2) ethylenically unsaturated monomer(s), e.g., styrene or mixture thereof with acrylonitrile, while (1) and (2) are dispersed or dissolved in an excess of a polyahl, i.e., an active hydrogen polyfunctional compound.
    Type: Grant
    Filed: May 9, 1985
    Date of Patent: February 3, 1987
    Assignee: The Dow Chemical Company
    Inventors: Thomas E. Fisk, Dwight K. Hoffman
  • Patent number: 4588830
    Abstract: An adduct of a heteroatomic monomer, e.g., gamma-methacryloxypropyl trimethoxysilane and a monoahl, e.g., a monohydroxyl polyalkylene oxide or a polyahl, e.g., a polypropylene glycol, is usefully employed in the preparation of stable copolymer dispersions of the type used in the production of polyurethane foams and polyurethane elastomers.The copolymer dispersion is prepared by addition copolymerization of (1) the adduct with (2) ethylenically unsaturated monomer(s), e.g., styrene or mixture thereof with acrylonitrile, while (1) and (2) are dispersed or dissolved in an excess of a polyahl, i.e., an active hydrogen polyfunctional compound.
    Type: Grant
    Filed: December 9, 1982
    Date of Patent: May 13, 1986
    Assignee: The Dow Chemical Company
    Inventors: Thomas E. Fisk, Dwight K. Hoffman
  • Patent number: 4513124
    Abstract: An adduct of a monoahl, e.g., a monohydroxyl polyalkylene oxide, and an active ethylenically unsaturated coreactant monomer, methacryloyl chloride, is usefully employed in the preparation of stable copolymer dispersions of the type used in the production of polyurethane foams and polyurethane elastomers.The copolymer dispersion is prepared by addition copolymerization of (1) the adduct with (2) ethylenically unsaturated monomers(s), e.g., styrene or mixture thereof with acrylonitrile, while (1) and (2) are dispersed or dissolved in an excess of an active hydrogen polyfunctional compound.
    Type: Grant
    Filed: February 14, 1983
    Date of Patent: April 23, 1985
    Assignee: The Dow Chemical Company
    Inventor: Dwight K. Hoffman
  • Patent number: 4460715
    Abstract: A stable copolymer dispersion is prepared by addition copolymerization of (1) a monomeric adduct of an active hydrogen compound, e.g., a polyether polyol, and an acrylyl compound such as methacryloyl chloride with (2) ethylenically unsaturated monomer(s), e.g., styrene or a mixture thereof with acrylonitrile, while (1) and (2) are dispersed or dissolved in an excess of an active hydrogen polyfunctional compound such as a polyether polyol. The molar ratio of acrylyl moiety to active hydrogen compound is less than 0.1:1. The resulting dispersion has a controlled particle size and a viscosity such that it is suitably employed in the production of polyurethane foams.
    Type: Grant
    Filed: November 10, 1981
    Date of Patent: July 17, 1984
    Assignee: The Dow Chemical Company
    Inventors: Dwight K. Hoffman, Robert F. Harris, Nancy B. Tefertiller, Randall C. Rains