Patents by Inventor Willem Sietses

Willem Sietses 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).

  • Preparing powder primer of thermoset binder and PVdF-compatible thermoplastic
    Patent number: 6037412
    Abstract: Powder compositions comprising about 5-15 wt % of PVdF-compatible thermoplastic resin, about 50-90 wt % of a thermosetting binder system, about 0-35 wt % of pigments and about 0-3 wt % of leveling agent are disclosed which are particularly suitable for use as primers with a later application of a pigmented PVdF-based top coating. Preferred compositions are based on an epoxy system containing about 8 wt % of PVdF or acrylic thermoplastic resin, 5-25 wt % of pigments and 0.7-1 wt % of leveling agent.
    Type: Grant
    Filed: July 14, 1999
    Date of Patent: March 14, 2000
    Assignee: Fina Research, S.A.
    Inventors: Ludwig Karl Rijkse, Willem Sietses, Michel Gillard
  • Powder primer of thermosetting binder and PVdF-compatible thermoplastic
    Patent number: 5932657
    Abstract: Powder compositions comprising about 5-15 wt % of PVdF-compatible thermoplastic resin, about 50-90 wt % of a thermosetting binder system, about 0-35 wt % of pigments and about 0-3 wt % of leveling agent are disclosed which are particularly suitable for use as primers with a later application of a pigmented PVdF-based top coating. Preferred compositions are based on an epoxy system containing about 8 wt % of PVdF or acrylic thermoplastic resin, 5-25 wt % of pigments and 0.7-1 wt % of leveling agent.
    Type: Grant
    Filed: July 21, 1994
    Date of Patent: August 3, 1999
    Assignee: Fina Research, S. A.
    Inventors: Ludwig Karl Rijkse, Willem Sietses, Michel Gillard
  • PVdF-based powder coatings
    Patent number: 5030394
    Abstract: A process for preparing pigmented PVdF-based powder coating products is disclosed, which comprises the steps of (i) mixing PVdF resin with a compatible thermoplastic resin, preferably PMMA in a weight ratio of about 80:20 to 40:60, with pigments, and with a small amount of flow promoter, (ii) pelletizing the mixture of (i), and (iii) cryogenically grinding the pellets and sieving the large particles. Also disclosed is a process for coating a substrate, comprising the steps of (a) applying the above prepared powder coating product on a substrate, and (b) subjecting to a heat treatment.
    Type: Grant
    Filed: November 8, 1988
    Date of Patent: July 9, 1991
    Assignee: Labofina, S.A.
    Inventors: Willem Sietses, Tjalling M. Plantenga, Jean-Paul Dekerk
  • PVdF-based powder coatings
    Patent number: 4770939
    Abstract: A process for preparing pigmented PVdF-based powder coating products is disclosed, which comprises the steps of (i) mixing PVdF resin with a compatible thermoplastic resin, preferably PMMA in a weight ratio of about 80:20 to 40:60, with pigments, and with a small amount of flow promoter, (ii) pelletizing the mixture of (i), and (iii) cryogenically grinding the pellets and sieving the large particles. Also disclosed is a process for coating a substrate, comprising the steps of (a) applying the above prepared powder coating product on a substrate, and (b) subjecting to a heat treatment.
    Type: Grant
    Filed: August 27, 1987
    Date of Patent: September 13, 1988
    Assignee: Labofina, S.A.
    Inventors: Willem Sietses, Tjalling M. Plantenga, Jean-Paul Dekerk