Patents by Inventor Calvin E. Pannell

Calvin E. Pannell 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).

  • Purification of polymer solution
    Patent number: 4177343
    Abstract: Undesired impurities in polymer solutions, such as amine scavenging agents or hydrochloric acid, are removed by passing a contaminated polymer solution through a strong acid cation exchange resin bed.
    Type: Grant
    Filed: December 19, 1977
    Date of Patent: December 4, 1979
    Assignee: The Dow Chemical Company
    Inventor: Calvin E. Pannell
  • Purification of polycarbonate solution
    Patent number: 4078999
    Abstract: Substantial depletion of pyridine hydrochloride from a polycarbonate reaction solution is accomplished in a non-aqueous system by dialyzing the polycarbonate solution against a sweep solvent in a permeability separatory unit.
    Type: Grant
    Filed: November 1, 1976
    Date of Patent: March 14, 1978
    Assignee: The Dow Chemical Company
    Inventor: Calvin E. Pannell