Patents by Inventor Robert P. Levek

Robert P. Levek 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: 4160112
    Abstract: A process for isolating crude pentabromophenol containing occluded bromine and hydrogen bromide as impurities comprising the steps of contacting the crude pentabromophenol with a strong acid such as hydrobromic acid, sulfuric acid, hydrochloric acid and phosphoric acid; heating the mixture in order to remove excess bromine; and recovering of the pentabromophenol, whereby formation of carbonyl-group-containing impurities during isolation is minimized.
    Type: Grant
    Filed: February 13, 1978
    Date of Patent: July 3, 1979
    Assignee: Great Lakes Chemical Corporation
    Inventors: Robert P. Levek, Rastko I. Mamuzic, John L. Sands
  • Patent number: 4089912
    Abstract: This application discloses stabilized flame-retardant styrenic polymer compositions comprising a bromine-containing flame-retardant, antimony trioxide and a three component stabilizer comprising a dialkyltin maleate, a hindered phenolic antioxidant, and a member selected from the group consisting of anhydrides of a cyclic dicarboxylic acid, ester derivatives thereof, imide derivatives thereof, and monomeric and dimeric polyesters.
    Type: Grant
    Filed: July 28, 1976
    Date of Patent: May 16, 1978
    Assignee: Great Lakes Chemical Corporation
    Inventors: Robert P. Levek, David O. Williams
  • Patent number: 4078089
    Abstract: Thixotropic fumigant compositions comprising liquid haloaliphatic hydrocarbon based fumigants and silica gelling agents may be stabilized through the use of an epoxide stabilizing agent and by controlling the purity of the raw materials such that the haloaliphatic hydrocarbon contains alcoholic impurities such as methyl alcohol in methyl bromide at a level of not more than about 200 ppm and such that the composition contains an initial water content of not more than about 500 ppm. Such compositions have utility as soil fumigants having significantly improved shelf life relative to prior gelled fumigant compositions for use in the control of nematodes, weeds, and weed seeds.
    Type: Grant
    Filed: April 19, 1977
    Date of Patent: March 7, 1978
    Assignee: Great Lakes Chemical Corporation
    Inventors: Robert P. Levek, Perry C. Heath