Patents by Inventor Hendrik Grunstra

Hendrik Grunstra 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: 6045923
    Abstract: The invention is directed to a co-extruded tape or yarn of the ABA-type, as well as to a process for producing such a tape, comprising a central layer and two top layers, the composition of the central layer (B) and the top layers (A) being different, wherein the central layer (B) is based on at least one propylene polymer, or on at least one ethylene polymer having a density of more than 935 kg/m.sup.3, and the top layers (A) are based on at least one ethylene copolymer with one or more C.sub.3 -C.sub.8 olefins, and the tape or yarn having a thickness of 50 to 150 .mu.m and a stretch ratio between 6 and 10.
    Type: Grant
    Filed: November 24, 1997
    Date of Patent: April 4, 2000
    Assignee: Lankhorst Indutech B.V.
    Inventors: Rudolf Hendrik Kok, Hendrik Grunstra
  • Patent number: 5993711
    Abstract: For manufacturing tape or yarns, plastic polymer material is extruded into a film (20, 21) having a pattern of parallel, longitudinal, alternating ribs (31, 32) and deep, narrow grooves (33, 34) on each of its two opposite sides, at least a plurality of the grooves (33, 34) in one side each being located diametrically opposite one of the grooves (34, 33) in the other, opposite side. Yarns and tapes obtained in the form of or from such a film typically have a substantially improved tensile strength and are more supple and smooth.
    Type: Grant
    Filed: January 30, 1998
    Date of Patent: November 30, 1999
    Assignee: Lankhorst Indutech B.V.
    Inventor: Hendrik Grunstra