Patents by Inventor Jagdish C. Sehra

Jagdish C. Sehra 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).

  • Preparation of polycarbonates with bioxyanion catalyst
    Patent number: 5288838
    Abstract: The invention discloses an improved process for the preparation of aryl polycarbonates. The process involves reacting aryl carbonate and dihydric phenol in the melt phase with a catalyst belonging to the class of quaternary ammonium bioxyanions having the general formula: ##STR1## Wherein `X` represents a carboxylate or a phenolate group or a mixture thereof and `R` represents alkyl or aryl.
    Type: Grant
    Filed: April 9, 1992
    Date of Patent: February 22, 1994
    Assignee: Council of Scientific & Industrial Research
    Inventors: Swaminathan Sivaram, Jagdish C. Sehra, Venkat S. Iyer, Ishwar S. Bhardwaj, Sheo Satish
  • Solid state process for the preparation of high molecular weight poly(arylcarbonate)s from amorphous oligomer
    Patent number: 5266659
    Abstract: The invention disclosed is an improved process for the preparation of high molecular weight poly(arylcarbonate), the molecular weight ranging from 45,000-60,000 (corresponding to n.sub.inh 0.8 to 1.0) The process involves heating in a controlled manner, a BPA-polycarbonate oligomer in the presence of a catalyst selected from alkali metal aryl acid, alkali metal borohydrial and a quarternary ammonium salt of bioxiyanion derived from a carboxylic acid poly(arylcarbonate)s of high molecular weight produced by the process of present invention show enhanced crystallinity.
    Type: Grant
    Filed: May 5, 1992
    Date of Patent: November 30, 1993
    Assignee: Council of Scientific & Industrial Research
    Inventors: Swaminathan Sivaram, Jagdish C. Sehra, Venkat S. Iyer, Koyalagunta Ravindranath