Patents by Inventor Nitis Sarkar

Nitis Sarkar 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 preparing vinylidene chloride or vinyl chloride polymer by suspension polymerization
    Patent number: 5342910
    Abstract: A process for preparing a polymer or copolymer from polymerizable monomers by suspension polymerization whereby foam formation during the removal of residual monomers is inhibited, which process comprises adding at least one salt of an inorganic acid having an anionic valency of at least 2 to the polymer slurry prior to the removal of the residual monomer.
    Type: Grant
    Filed: December 18, 1992
    Date of Patent: August 30, 1994
    Assignee: The Dow Chemical Company
    Inventors: Susan M. Kling, Nitis Sarkar
  • Water-soluble aromatic polyamides and polyureas
    Patent number: 4895660
    Abstract: Novel sulfonated polyamide and polyurea materials are described. The polymers are water-soluble or water-dispersible, if not crosslinked. The polymers can be crosslinked with polyvalent cations or crosslinking agents. The polymers have utility as membranes, thickeners, coatings and adhesives.
    Type: Grant
    Filed: April 5, 1989
    Date of Patent: January 23, 1990
    Assignee: The Dow Chemical Company
    Inventors: Larry D. Kershner, Charles E. Reineke, Nitis Sarkar, Larry R. Wilson
  • Water-insoluble, crosslinked, sulfonated aromatic polyamide
    Patent number: 4824916
    Abstract: Novel sulfonated polyamide and polyurea materials are described. The polymers are water-soluble or water-dispersible, if not crosslinked. The polymers can be crosslinked with polyvalent cations or crosslinking agents. The polymers have utility as membranes, thickeners, coatings and adhesives.
    Type: Grant
    Filed: July 14, 1986
    Date of Patent: April 25, 1989
    Assignee: The Dow Chemical Company
    Inventors: Larry D. Kershner, Charles E. Reineke, Nitis Sarkar, Larry R. Wilson
  • Water-based hydraulic fluids
    Patent number: 4469611
    Abstract: Substantially oil-free aqueous industrial fluids possess superior lubricating and wear preventing characteristics and are useful as hydraulic fluids and metalworking compositions. Fluids of the invention comprise (1) an aqueous liquid and (2) a water-soluble synthetic addition copolymer of (a) an ethylenically unsaturated polyalkyleneoxy containing monomer, (b) an ethylenically unsaturated water-soluble monomer and, optionally, (c) an ethylenically unsaturated water-insoluble monomer.The industrial fluids exhibit good Newtonian behavior and mechanical stability at higher shear.
    Type: Grant
    Filed: November 1, 1982
    Date of Patent: September 4, 1984
    Assignee: The Dow Chemical Company
    Inventors: Kenneth L. Snyder, Jr., William H. Keskey, Nitis Sarkar
  • Pharmaceutical capsules from improved thermogelling methyl cellulose ethers
    Patent number: 4001211
    Abstract: Improved thermogelling methyl cellulose ether compositions for use in preparing pharmaceutical capsules by the pin dip coating process are prepared by blending the properties of water soluble methyl and C.sub.2 -C.sub.3 hydroxyalkyl cellulose ethers to achieve an essentially Newtonian dip coating solution and a rapid high thermal gel yield strength. These properties require a cellulose ether with a relatively narrow molecular weight distribution. Blends of low viscosity methyl cellulose and hydroxypropylmethyl cellulose provide particularly suitable dip solution properties, gel yield strength, and capsule dissolution rates.
    Type: Grant
    Filed: October 1, 1975
    Date of Patent: January 4, 1977
    Assignee: The Dow Chemical Company
    Inventor: Nitis Sarkar