Patents by Inventor Marvin C. Hawkins

Marvin C. Hawkins 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).

  • Robust propellant liner and interfacial propellant burn rate control
    Patent number: 5985361
    Abstract: A robust polyurethane liner is disclosed for solid propellant rocket motors which is insensitive to large variations in stoichiometry, exhibits increased cohesive strength and, when used in combination with a unique two coat (wet coat) liner process described below, modifies the ballistic properties of the adjacent interfacial propellant layer. The liner compositions include a polymeric binder having a plurality of reactive hydroxyl functional groups and a curing agent having a plurality of reactive isocyanate functional groups. The quantity of binder and curing agent is selected such that the NCO/OH ratio is in the range from 1.5 to 4.5. Diisocyanate curing agents are particularly useful. A bonding agent, such as a polyfunctional aziridine compound, is typically present in the liner composition in an amount ranging from about 3% to about 5%, by weight. An oligomer catalyst is included in the liner composition in an amount ranging from about 15% to about 50%, by weight. Diammonium phosphate ((NH.sub.4).sub.
    Type: Grant
    Filed: April 16, 1998
    Date of Patent: November 16, 1999
    Assignee: Thiokol Corporation
    Inventors: Larry W. Poulter, Ronald W. Nelson, Robert B. Smalley, Jr., Marvin C. Hawkins
  • Robust propellant liner and interfacial propellant burn rate control
    Patent number: 5767221
    Abstract: A robust polyurethane liner is disclosed for solid propellant rocket motors which is insensitive to large variations in stoichiometry, exhibits increased cohesive strength and, when used in combination with a unique two coat (wet coat) liner process described below, modifies the ballistic properties of the adjacent interfacial propellant layer. The liner compositions include a polymeric binder having a plurality of reactive hydroxyl functional groups and a curing agent having a plurality of reactive isocyanate functional groups. The quantity of binder and curing agent is selected such that the NCO/OH ratio is in the range from 1.5 to 4.5. Diisocyanate curing agents are particularly useful. A bonding agent, such as a polyfunctional aziridine compound, is typically present in the liner composition in an amount ranging from about 3% to about 5%, by weight. An oligomer catalyst is included in the liner composition in an amount ranging from about 15% to about 50%, by weight. Diammonium phosphate ((NH.sub.4).sub.
    Type: Grant
    Filed: May 24, 1995
    Date of Patent: June 16, 1998
    Assignee: Thiokol Corporation
    Inventors: Larry W. Poulter, Ronald W. Nelson, Robert B. Smalley, Jr., Marvin C. Hawkins