Patents by Inventor Vasant D. Chapnerkar

Vasant D. Chapnerkar 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).

  • Process for production of rhombic shaped precipitated calcium carbonate
    Patent number: 5332564
    Abstract: A process for producing rhombic or barrel shaped precipitated calcium carbonate. Quicklime is slaked in an aqueous solution containing about 0.1% to about 2% by weight of a sugar, based upon the weight of the CaCO.sub.3 to be produced. Carbon dioxide is added to the slaked lime slurry at a preferred temperature of about 50.degree. F.-70.degree. F. until the pH drops from about 11-12 to about 7-8.
    Type: Grant
    Filed: July 10, 1992
    Date of Patent: July 26, 1994
    Assignee: ECC International Inc.
    Inventors: Vasant D. Chapnerkar, Mohan N. Badgujar
  • Method for preparing acid resistant calcium carbonate pigments
    Patent number: 5164006
    Abstract: A method for preparing an acid resistant calcium carbonate pigment. An aqueous slurry of particulate calcium carbonate is provided at a pH of from about 11.0 to 12.0 and having from 2 to 5 g/l of excess calcium hydroxide. The slurry temperature is brought to the range of about 75.degree. to 80.degree. C., and sodium silicate solution is slowly mixed therewith to provide on a solid dry weight ratio from about 5 to 10% sodium silicate to calcium carbonate. Gaseous carbon dioxide is added to bring the slurry pH to the range of about 10.2 to 10.7, and the slurry is cooled to about 25.degree. to 30.degree. C. Finally zinc chloride is added to the cooled slurry to bring the pH to within the range of 7.5 to 8.0.
    Type: Grant
    Filed: April 8, 1991
    Date of Patent: November 17, 1992
    Assignee: ECC America Inc.
    Inventors: Vasant D. Chapnerkar, Vicente B. Lasmarias, Vijay K. Mathur