Patents by Inventor Volker H. von Ahn

Volker H. von Ahn 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).

  • 1,2-bis-adducts of stable nitroxides with substituted ethylenes and stabilized compositions
    Patent number: 6218536
    Abstract: 1,2-Bis-adducts of stable hindered nitroxide compounds with substituted ethylenes are prepared by reacting two equivalents of nitroxyl compound with an ethylenically unsaturated compound such as styrene or an acrylate ester. These adducts are very effective inhibitors to prevent the premature polymerization of ethylenically unsaturated monomers when such monomers are distilled, processed or stored.
    Type: Grant
    Filed: October 7, 1998
    Date of Patent: April 17, 2001
    Assignee: Ciba Specialty Chemcials Corporation
    Inventors: Glen Thomas Cunkle, Thomas F. Thompson, Volker H. von Ahn, Roland A. E. Winter
  • Inhibiting polymerization of vinyl aromatic monomers
    Patent number: 6117276
    Abstract: When a nitroxyl compound is heated in an oxygen-free atmosphere with a vinyl aromatic monomer at 50-140.degree. C. for up to 60 days, it forms an activated inhibitor mixture which is superior to the nitroxyl compound itself in preventing the premature polymerization of a vinyl aromatic monomer during its processing and purification.
    Type: Grant
    Filed: March 26, 1998
    Date of Patent: September 12, 2000
    Assignee: Nalco/Exxon Energy Chemicals, L.P.
    Inventors: Glen T. Cunkle, Thomas F. Thompson, Volker H. von Ahn, Roland A. E. Winter
  • Process for making 5-thio-substituted benzotriazole UV absorbers
    Patent number: 5942626
    Abstract: 2-(2-Hydroxyphenyl)-2H-benzotriazole UV-absorbers substituted at the 5-position of the benzo ring by a thioether group exhibit enhanced absorption in the near visible range (over 350 nm) allowing said compounds to be particularly effective in protecting polymer systems which are prone to degradation caused by actinic irradiation with wavelengths over 350 nm.
    Type: Grant
    Filed: April 10, 1996
    Date of Patent: August 24, 1999
    Assignee: Ciba Specialty Chemicals Corporation
    Inventors: Roland A.E. Winter, Volker H. von Ahn, Tyler A. Stevenson, Mark S. Holt, Ramanathan Ravichandran
  • 1,2-Bis-adducts of stable nitroxides with substituted ethylenes and stabilized compositions
    Patent number: 5844025
    Abstract: 1,2-Bis-adducts of stable hindered nitroxide compounds with substituted ethylenes are prepared by reacting two equivalents of nitroxyl compound with an ethylenically unsaturated compound such as styrene or an acrylate ester. These adducts are very effective inhibitors to prevent the premature polymerization of ethylenically unsaturated monomers when such monomers are distilled, processed or stored.
    Type: Grant
    Filed: December 2, 1996
    Date of Patent: December 1, 1998
    Assignee: Ciba Specialty Chemicals Corporation
    Inventors: Glen Thomas Cunkle, Thomas F. Thompson, Volker H. von Ahn, Roland A. E. Winter
  • 7-substituted quinone methides as inhibitors for unsaturated monomers
    Patent number: 5750765
    Abstract: Ethylenically unsaturated monomers are protected from premature polymerization during manufacture and storage by the incorporation therein of an effective stabilizing amount of a 7-substituted quinone methide compound.
    Type: Grant
    Filed: August 27, 1996
    Date of Patent: May 12, 1998
    Assignee: Ciba Specialty Chemicals Corporation
    Inventors: Peter Nesvadba, Samuel Evans, Matthew E. Gande, Volker H. von Ahn, Roland A. E. Winter
  • 7-substituted quinone methides as inhibitors for unsaturated monomers
    Patent number: 5670692
    Abstract: Ethylenically unsaturated monomers are protected from premature polymerization during manufacture and storage by the incorporation therein of an effective stabilizing amount of a 7-substituted quinone methide compound.
    Type: Grant
    Filed: August 27, 1996
    Date of Patent: September 23, 1997
    Assignee: Ciba-Geigy Corporation
    Inventors: Peter Nesvadba, Samuel Evans, Matthew E. Gande, Volker H. von Ahn, Roland A. E. Winter
  • Inhibition of unsaturated monomers with 7-aryl quinone methides
    Patent number: 5616774
    Abstract: Ethylenically unsaturated monomers are protected from premature polymerization during manufacture and storage by the incorporation therein of an effective stabilizing amount of a 7-aryl quinone methide compound.
    Type: Grant
    Filed: April 14, 1995
    Date of Patent: April 1, 1997
    Assignee: Ciba-Geigy Corporation
    Inventors: Samuel Evans, Matthew E. Gande, Peter Nesvadba, Volker H. von Ahn, Roland A. E. Winter
  • 2-(2-hydroxy-3-.alpha. cumyl-5-tert nonyl or dodecyl phenyl)-2H- Benzotriazole UV Absorbers
    Patent number: 5607987
    Abstract: Soluble and thermally stable benzotriazole UV absorbers typified by those of formula I ##STR1## where R.sub.1 is hydrogen or chloro, R.sub.2 is alkyl or --CH.sub.2 CH.sub.2 COOR.sub.4 where R.sub.4 is hydrogen, alkyl or alkyl substituted with hydroxyl, and R.sub.3 is .alpha.-cumyl, provide excellent light stability protection to electro coat, base coat or clear coat finishes. The new soluble, crystalline form of 2-(2-hydroxy-3-.alpha.-cumyl-5-tert-octylphenyl)-2H-benzotriazole is particularly effective.
    Type: Grant
    Filed: April 5, 1996
    Date of Patent: March 4, 1997
    Assignee: Ciba-Geigy Corporation
    Inventors: Roland A. E. Winter, Ramanathan Ravichandran, Mark S. Holt, Volker H. von Ahn, Joseph E. Babiarz, David G. Leppard
  • 7-substituted quinone methides as inhibitors for unsaturated monomers
    Patent number: 5583247
    Abstract: Ethylenically unsaturated monomers are protected from premature polymerization during manufacture and storage by the incorporation therein of an effective stabilizing amount of a 7-substituted quinone methide compound.
    Type: Grant
    Filed: April 14, 1995
    Date of Patent: December 10, 1996
    Assignee: Ciba-Geigy Corporation
    Inventors: Peter Nesvadba, Samuel Evans, Matthew E. Gande, Volker H. von Ahn, Roland A. E. Winter
  • Crystalline form of 2-(2-hydroxy-3-.alpha.-cumyl-5-tert-octylphenyl)-2H-benzotriazole
    Patent number: 5574166
    Abstract: Soluble and thermally stable benzotriazole UV absorbers typified by those of formula I ##STR1## where R.sub.1 is hydrogen or chloro, R.sub.2 is alkyl or --CH.sub.2 CH.sub.2 COOR.sub.4 where R.sub.4 is hydrogen, alkyl or alkyl substituted with hydroxyl, and R.sub.3 is .alpha.-cumyl, provide excellent light stability protection to electro coat, base coat or clear coat finishes. The new soluble, crystalline form of 2-(2-hydroxy-3-.alpha.-cumyl-5-tert-octylphenyl)-2H-benzotriazole is particularly effective.
    Type: Grant
    Filed: April 19, 1995
    Date of Patent: November 12, 1996
    Assignee: Ciba-Geigy Corporation
    Inventors: Roland A. E. Winter, Ramanathan Ravichandran, Mark S. Holt, Volker H. von Ahn, Joseph E. Babiarz, David G. Leppard
  • Electro coat/base coat/clear coat finishes stabilized with soluble and thermally stable benzotriazole UV absorbers
    Patent number: 5563242
    Abstract: Soluble and thermally stable benzotriazole UV absorbers typified by those of formula I ##STR1## where R.sub.1 is hydrogen or chloro, R.sub.2 is alkyl or --CH.sub.2 CH.sub.2 COOR.sub.4 where R.sub.4 is hydrogen, alkyl or alkyl substituted with hydroxyl, and R.sub.3 is .alpha.-cumyl, provide excellent light stability protection to electro coat, base coat or clear coat finishes. The new soluble, crystalline form of 2-(2-hydroxy-3-.alpha.-cumyl-5-tert-octylphenyl)-2H-benzotriazole is particularly effective.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: October 8, 1996
    Assignee: Ciba-Geigy Corporation
    Inventors: Roland A. E. Winter, Ramanathan Ravichandran, Mark S. Holt, Volker H. von Ahn, Joseph E. Babiarz, David G. Leppard
  • 2-(2-hydroxy-3-.alpha.-cumyl-5-nonylor 5-dodecylphenyl)-2H-benzotriazole
    Patent number: 5554760
    Abstract: Soluble and thermally stable benzotriazole UV absorbers typified by those of formula I ##STR1## where R.sub.1 is hydrogen or chloro, R.sub.2 is alkyl or --CH.sub.2 CH.sub.2 COOR.sub.4 where R.sub.4 is hydrogen, alkyl or alkyl substituted with hydroxyl, and R.sub.3 is .alpha.-cumyl, provide excellent light stability protection to electro coat, base coat or clear coat finishes. The new soluble, crystalline form of 2-(2-hydroxy-3-.alpha.-cumyl-5-tert-octylphenyl)-2H-benzotriazole is particularly effective.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: September 10, 1996
    Assignee: Ciba-Geigy Corporation
    Inventors: Roland A. E. Winter, Ramanathan Ravichandran, Mark S. Holt, Volker H. von Ahn, Joseph E. Babiarz, David G. Leppard
  • Method for inhibiting premature polymerization of vinyl aromatic monomers
    Patent number: 5545782
    Abstract: Nitroxyl inhibitors in combination with some oxygen reduce the premature polymerization of vinyl aromatic monomers during the manufacturing processes for such monomers. Even small quantities of air used in combination with the nitroxyl inhibitors result in vastly prolonged inhibition times for said monomers.
    Type: Grant
    Filed: May 17, 1995
    Date of Patent: August 13, 1996
    Assignee: Ciba-Geigy Corporation
    Inventors: Roland A. E. Winter, Volker H. von Ahn
  • Method for inhibiting premature polymerization of vinyl aromatic monomers
    Patent number: 5545786
    Abstract: Nitroxyl inhibitors in combination with some oxygen reduce the premature polymerization of vinyl aromatic monomers during the manufacturing processes for such monomers. Even small quantities of air used in combination with the nitroxyl inhibitors result in vastly prolonged inhibition times for said monomers.
    Type: Grant
    Filed: February 3, 1995
    Date of Patent: August 13, 1996
    Assignee: Ciba-Geigy Corporation
    Inventors: Roland A. E. Winter, Volker H. von Ahn
  • Compositions stabilized with 5-thio-substituted benzotriazole UV-absorbers
    Patent number: 5516914
    Abstract: 2-(2-Hydroxyphenyl)-2H-benzotriazole UV-absorbers substituted at the 5-position of the benzo ring by a thioether group exhibit enhanced absorption in the near visible range (over 350 nm) allowing said compounds to be particularly effective in protecting polymer systems which are prone to degradation caused by actinic irradiation with wavelengths over 350 nm.
    Type: Grant
    Filed: November 1, 1993
    Date of Patent: May 14, 1996
    Assignee: Ciba-Geigy Corporation
    Inventors: Roland A. E. Winter, Volker H. von Ahn, Tyler A. Stevenson, Mark S. Holt, Ramanathan Ravichandran
  • Compositions stabilized with 5-sulfonyl-substituted benotriazole UV-absorbers
    Patent number: 5436349
    Abstract: 2-(2-Hydroxyphenyl)-2H-benzotriazole UV-absorbers substituted at the 5-position of the benzo ring by a sulfoxide or sulfone group exhibit enhanced absorption in the near visible range (over 350 nm) allowing said compounds to be particularly effective in protecting polymer systems which are prone to degradation caused by actinic irradiation with wavelengths over 350 nm.
    Type: Grant
    Filed: November 1, 1993
    Date of Patent: July 25, 1995
    Assignee: Ciba-Geigy Corporation
    Inventors: Roland A. E. Winter, Volker H. von Ahn, Tyler A. Stevenson, Mark S. Holt, Ramanathan Ravichandran
  • 5-sulfonyl-substituted benzotriazole UV-absorbers
    Patent number: 5280124
    Abstract: 2-(2-Hydroxyphenyl)-2H-benzotriazole UV-absorbers substituted at the 5-position of the benzo ring by a sulfoxide or sulfone group exhibit enhanced absorption in the near visible range (over 350 nm) allowing said compounds to be particularly effective in protecting polymer systems which are prone to degradation caused by actinic irradiation with wavelengths over 350 nm.
    Type: Grant
    Filed: February 5, 1992
    Date of Patent: January 18, 1994
    Assignee: Ciba-Geigy Corporation
    Inventors: Roland A. E. Winter, Volker H. von Ahn, Tyler A. Stevenson, Mark S. Holt, Ramanathan Ravichandran
  • 5-thio-substituted benzotriazole UV-absorbers
    Patent number: 5278314
    Abstract: 2-(2-Hydroxyphenyl)-2H-benzotriazole UV-absorbers substituted at the 5-position of the benzo ring by a thioether group exhibit enhanced absorption in the near visible range (over 350 nm) allowing said compounds to be particularly effective in protecting polymer systems which are prone to degradation caused by actinic irradiation with wavelengths over 350 nm.
    Type: Grant
    Filed: February 5, 1992
    Date of Patent: January 11, 1994
    Assignee: Ciba-Geigy Corporation
    Inventors: Roland A. E. Winter, Volker H. von Ahn, Tyler A. Stevenson, Mark S. Holt, Ramanathan Ravichandran
  • Inhibiting polymerization of vinyl aromatic monomers
    Patent number: 5254760
    Abstract: The polymerization of a vinyl aromatic compound, such as styrene, during distillation or purification is very effectively inhibited by the presence of at least one stable nitroxyl compound together with at least one aromatic nitro compound.
    Type: Grant
    Filed: July 29, 1992
    Date of Patent: October 19, 1993
    Assignee: Ciba-Geigy Corporation
    Inventors: Roland A. E. Winter, Sheng-Shing Li, Leslie R. Gatechair, Volker H. von Ahn