Patents by Inventor Robert M. Leeuwendal

Robert M. Leeuwendal 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: 6441072
    Abstract: The invention relates to a polyamide composition for the production of electrical and electronic components that are suitable for the conditions of the surface mounting technology. In particular, the composition exhibits a high resistance to blistering during the reflow soldering process. The composition according to the invention comprises (a) a polyamide having a melting point higher than 280° C., (b) a polymer having a melting point lower than 230° C., (c) a halogen-containing compound, (d) optionally a synergist for the flame-retardant properties (e) reinforcing material (f) optionally other additives. A particularly good resistance to blistering is achieved if (f) contains at least a compound with acid imide groups.
    Type: Grant
    Filed: September 1, 2000
    Date of Patent: August 27, 2002
    Assignee: DSM N.V.
    Inventors: Hubertus G. J. Havenith, Wilhelmus J. M. Sour, Johannes Tijssen, Robert M. Leeuwendal
  • Patent number: 5965689
    Abstract: The invention relates to electrical and electronic components made of a polyamide composition and possessing an improved resistance under soldering conditions, particularly when the surface mounting technique is used. This is achieved by using a polyamide composition whose main chain essentially consists of units derived from aliphatic dicarboxylic acids and diamines or .alpha.,.omega.-amino acids, and in which 1-40% of the chain units are derived from 1,6-cyclohexanedicarboxylic acid and an aliphatic diamine, or from 1,4-cyclohexanediamine and an aliphatic dicarboxylic acid.As a result, the temperature at which blisters are formed during soldering by the infrared method is 20-30.degree. C. higher than in the case of the homo-polyamide.
    Type: Grant
    Filed: March 19, 1998
    Date of Patent: October 12, 1999
    Assignee: DSM N.V.
    Inventors: Cornelis E. Koning, Petronella M. Knape, Robert M. Leeuwendal, Josefina M. A. Schiffer
  • Patent number: 5071894
    Abstract: A flame retardant polyamide composition including flame retardant effective amounts of (a) an iron compound and (b) a char forming thermoplastic polymer having aromatic groups in the backbone. A char stabilizing compound (c) may also be present. In a preferred embodiment (b) is a polyphenylene ether. In a preferred embodiment, (c) is anhydrous zinc borate or a wollastonite.
    Type: Grant
    Filed: August 3, 1990
    Date of Patent: December 10, 1991
    Assignee: Stamicarbon B.V.
    Inventors: Edward D. Weil, Navin G. Patel, Robert M. Leeuwendal