Patents by Inventor Konrad Stiefenhoefer

Konrad Stiefenhoefer 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).

  • Polyfunctional polyisocyanate polyadducts
    Patent number: 6632914
    Abstract: Polyfunctional polyisocyanate polyadducts are prepared by a process comprising (i) preparation of an adduct by reacting (a) an at least trifunctional component (a1) reactive with isocyanate groups or a difunctional component (a2) reactive with isocyanate groups or a mixture of the components (a1) and (a2) with (b) a di- or polyisocyanate, the reaction ratio being chosen so that on average the polyadduct (A) contains one isocyanate group and more than one group reactive with isocyanate groups, (ii) if required, intermolecular addition reaction of the adduct (A) to give a polyadduct (P) which contains on average one isocyanate group and more than two groups reactive with isocyanate groups, and (iii) reaction of the adduct (A) or of the polyadduct (P) with an at least difunctional component (c) reactive with isocyanate groups.
    Type: Grant
    Filed: June 21, 2001
    Date of Patent: October 14, 2003
    Assignee: BASF Aktiengesellschaft
    Inventors: Bernd Bruchmann, Konrad Stiefenhöfer
  • Dendritic and highly branched polyurethanes
    Patent number: 6376637
    Abstract: In a process for preparing dendritic or highly branched polyurethanes by reacting diisocyanates and/or polyisocyanates with compounds containing at least two groups which are reactive toward isocyanates, at least one of the reactants contains functional groups having a different reactivity compared to the other reactant and the reaction conditions are selected so that only certain reactive groups react with one another in each reaction step.
    Type: Grant
    Filed: January 26, 2000
    Date of Patent: April 23, 2002
    Assignee: BASF Corporation
    Inventors: Bernd Bruchmann, Ulrike Ehe, Frank Wingerter, Konrad Stiefenhöfer, Ulrich Treuling
  • Polymeric, catalytically active compounds, their preparation, and their use as catalysts in the preparation of polyisocyanates containing uretdione groups
    Patent number: 5637664
    Abstract: Polymeric, catalytically-active compounds having imidazole groups linked terminally and/or laterally to the polymer chain through reactive groups on the polymer chain are disclosed. The polymer chain is selected from the group consisting of polyether ketones; acidic, basic, or neutral ion exchange resins; polymeric isocyanates; polymers or copolymers containing maleic acid or maleic anhydride; and polymers containing benzyl halide groups.
    Type: Grant
    Filed: June 1, 1995
    Date of Patent: June 10, 1997
    Assignee: BASF Aktiengesellschaft
    Inventors: Bernd Bruchmann, Roland Minges, Christian Schade, Konrad Stiefenhoefer
  • Polymeric, catalytically active compounds, their preparation, and their use as catalysts in the preparation of polyisocyanates containing uretdione groups
    Patent number: 5565527
    Abstract: Polymeric, catalytically active compounds comprising polymer chains to which imidazole groups are linked terminally or laterally are used as catalysts for the dimerization of isocyanates.
    Type: Grant
    Filed: June 1, 1995
    Date of Patent: October 15, 1996
    Assignee: BASF Aktiengesellschaft
    Inventors: Bernd Bruchmann, Roland Minges, Christian Schade, Konrad Stiefenhoefer
  • Imidazole group containing polymeric catalysts their preparation, and their use in the preparation of isocyanates containing uretdione groups
    Patent number: 5449775
    Abstract: Polymeric, catalytically active compounds comprising polymer chains to which imidazole groups are linked terminally or laterally are used as catalysts for the dimerization of isocyanates.
    Type: Grant
    Filed: May 10, 1993
    Date of Patent: September 12, 1995
    Assignee: BASF Aktiengesellschaft
    Inventors: Bernd Bruchmann, Roland Minges, Christian Schade, Konrad Stiefenhoefer
  • Preparation of isocyanurate- and/or uretidone-containing polysiocyanates having a reduced color index and improved shelf life, and products prepared by this method
    Patent number: 5436336
    Abstract: Isocyanurate- and/or uretidone-containing polyisocyanates having a reduced color index and improved shelf life are prepared by conventional catalytic oligomerization of aliphatic and/or cycloaliphatic diisocyanates and treatment of the oligomerization products with peroxycarboxylic acids.
    Type: Grant
    Filed: June 13, 1994
    Date of Patent: July 25, 1995
    Assignee: BASF Aktiengesellschaft
    Inventors: Bernd Bruchmann, Stefan Wolff, Konrad Stiefenhoefer