Patents by Inventor Johannes Jacobus van Heijkant

Johannes Jacobus van Heijkant 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: 6277946
    Abstract: A method is provided for the preparation of polycarbonates by the reaction of a diaryl carbonate, such as DPC and a dihydric phenol, such as BPA. The method utilizes the steps of successively processing the diaryl carbonate and the dihydric phenol in a melt in a first reaction stage, a second reaction stage and at least a first polymerization stage, and shifts the processing conditions such that the desired low viscosity/high end-cap product is obtained. This is achieved by having the ratio of diaryl carbonate to dihydric phenol in the melt prior to the first reaction stage greater than 1.08; and by controlling the temperature and residence time in the first polymerization stage to provide a polycarbonate product having a melt flow rate at 250° C. of greater than 10 g/min and an end-cap level of at least 90%. The method of the invention can be used in a linear manufacturing process, in which there is one product produced.
    Type: Grant
    Filed: May 9, 2000
    Date of Patent: August 21, 2001
    Assignee: General Electric Company
    Inventors: Johannes Jacobus van Heijkant, Christopher Poirier, Tomoaki Shimoda, Akio Kanezawa, Carlos Godinez Seoane