Patents by Inventor Susan M. Ehrhardt

Susan M. Ehrhardt 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).

  • Rosin sizing at neutral to alkaline pH
    Patent number: 6033526
    Abstract: Disclosed is a method for sizing paper at a pH of about 5.0-8.5 by incorporating a sizing composition consisting essentially of (1) rosin, (2) a cationic polyamine resin at a weight ratio of rosin to cationic polyamine of about 5:1 to about 1:2, and (3) up to 0.3% alum. The cationic polyamine resin is selected from the group consisting of polyalkyleneamine-epihalohydrin resins, polyalkyleneamine-dicyandiamide-epihalohydrin resins, poly(diallylamine.HCl)-epihalohydrin resins, poly(methyldiallylamine.HCl)-epihalohydrin resins, epihalohydrin-modified polyethyleneimine resins, amine-modified poly(methyldiallylamine.HCl)-epihalohydrin resins and mixtures thereof.
    Type: Grant
    Filed: December 28, 1994
    Date of Patent: March 7, 2000
    Assignee: Hercules Incorporated
    Inventors: Susan M. Ehrhardt, D. Bruce Evans