Patents by Inventor Frank W. Lindewall

Frank W. Lindewall 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).

  • Process for the preparation of semi-rigid polyurethane foam having exceptional shock-absorbing properties and vehicle bumpers thereof
    Patent number: 4134610
    Abstract: A process is provided for producing semi-rigid polyurethane foams having exceptional shock-absorbing properties, even after repeated compression, prepared by the reaction of a polyisocyanate; a polyether polyol having a molecular weight within the range from about 2,000 to about 10,000; from about 1 to about 5% by weight of water per part by weight of polyether polyol; from about 1 to about 6% by weight of urea and/or thiourea per part by weight of polyether polyol; and a cross-linking compound having at least three active hydrogen atoms per molecule that are reactive with isocyanate groups and having a molecular weight below about 1000 in an amount from about 5 to about 25% by weight per part by weight of polyether polyol; the amount of polyisocyanate being selected to give an isocyanate index within the range from about 0.7 to about 1.4.
    Type: Grant
    Filed: December 27, 1976
    Date of Patent: January 16, 1979
    Assignee: Berol Kemi AB
    Inventor: Frank W. Lindewall