Patents by Inventor David J. Hardman

David J. Hardman 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).

  • Patent number: 5972691
    Abstract: Process for making polyamine-epihalohydrin resin products having very low levels of epihalohydrin or epihalohydrin hydrolyzates, particularly useful in papermaking, which includes, amongst other features, producing a polyamine-epihalohydrin polymer in aqueous solution, terminating the reaction by cooling, adjusting the pH of the polyamine-epihalohydrin solution to from about 7.5 to about 11 and concurrently heating the solution to about 35 to about 50.degree. C., and contacting the aqueous solution with selected microorganisms or an enzyme, and deactivating or removing the enzymes or microbes, cooling to about 20.degree. C. and stabilizing the composition by adjusting the pH to about 2.0 to 5.0 by the addition of acid.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: October 26, 1999
    Assignee: Hercules Incorporated
    Inventors: Robert Bates, Harvey J. Branton, David J. Hardman, Gary K. Robinson
  • Patent number: 5871616
    Abstract: Enzymatic dehalogenation of undesirable nitrogen-free organohalogen compounds is carried out by adding a dehalogenase to an aqueous composition comprising a nitrogen-free organohalogen compound and a nitrogen-containing cationic polymer. The enzymatic dehalogenation of the nitrogen-free organohalogen compound is achieved without any substantial effect upon the nitrogen-free organohalogen compound. The dehalogenation method may be carried out via continuous, batch, or semi-continuous processes.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: February 16, 1999
    Assignee: Hercules Incorporated
    Inventors: Alan Bull, David J. Hardman, Brian M. Stubbs, Paul J. Sallis
  • Patent number: 5843763
    Abstract: Enzymatic dehalogenation of undesirable nitrogen-free organohalogen compounds is carried out by adding a dehalogenase to an aqueous composition comprising a nitrogen-free organohalogen compound and a nitrogen-containing cationic polymer. The enzymatic dehalogenation of the nitrogen-free organohalogen compound is achieved without any substantial effect upon the nitrogen-free organohalogen compound. The dehalogenation method may be carried out via continuous, batch, or semi-continuous processes.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: December 1, 1998
    Assignee: Hercules Incorporated
    Inventors: Alan Bull, David J. Hardman, Brian M. Stubbs, Paul J. Sallis
  • Patent number: 5470742
    Abstract: Enzymatic dehalogenation of undesirable nitrogen-free organohalogen compounds is carried out by adding bacteria to an aqueous composition comprising a nitrogen-free organohalogen compound and a nitrogen-containing cationic polymer. The enzymatic dehalogenation of the nitrogen-free organohalogen compound is achieved without any substantial effect upon the nitrogen-free organohalogen compound. The dehalogenation method may be carried out via continuous, batch, or semi-continuous processes NCIMB 40271, 40272, 40273 and 40274 were deposited on Apr. 2, 1990. NCIMB 40313 was deposited on Aug. 31, 1990 and NCIMB 40383 was deposited on Mar. 11, 1991.
    Type: Grant
    Filed: May 16, 1994
    Date of Patent: November 28, 1995
    Assignee: Hercules Incorporated
    Inventors: Alan Bull, David J. Hardman, Brian M. Stubbs, Paul J. Sallis