Patents by Inventor Harold L. Nicholson

Harold L. Nicholson 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 solutions
    Patent number: 4587330
    Abstract: Cloudy material in organic diluent solutions of polymers prepared by anionic polymerization with a lithium initiator is removed by treating the polymer solutions resulting from the polymerization with boric acid, separating the solid material from the solutions, and isolating the polymer.
    Type: Grant
    Filed: February 22, 1985
    Date of Patent: May 6, 1986
    Assignee: Atlantic Richfield Company
    Inventors: David R. Warfel, Harold L. Nicholson
  • Semi-continuous process for making star-block copolymers
    Patent number: 4390663
    Abstract: A semi-continuous process for the preparation of star-block copolymers of 60 to 90% by weight of monovinyl aromatic compound and 10 to 40% by weight of conjugated diene monomer has been developed. The process reduces the time needed to produce the copolymer by shortening reaction time and eliminating the need for costly cleanout between runs. Novel star-block copolymers are prepared which have bimodal arm structures containing a series of tapered copolymer segments.
    Type: Grant
    Filed: February 24, 1982
    Date of Patent: June 28, 1983
    Assignee: Atlantic Richfield Company
    Inventor: Harold L. Nicholson
  • Semi-continuous process for making star-block copolymers
    Patent number: 4371661
    Abstract: A semi-continuous process for the preparation of star-block copolymers of 25-55% by weight of monovinyl aromatic compound and 45-75% by weight of conjugated diene monomer has been developed. The process reduces the time needed to produce the copolymer by shortening reaction time and eliminating the need for costly cleanout between runs.
    Type: Grant
    Filed: March 26, 1982
    Date of Patent: February 1, 1983
    Assignee: Atlantic Richfield Company
    Inventor: Harold L. Nicholson