Abstract: A sulfur cured rubber composition composed of selected natural rubber and carbon black for sensing pressure with reference to applied sinusoidal electrical energy.

Abstract: A method of preparing a composite of polyurethane bonded to the surface of a cured rubber substrate and the resulting composite. The method requires the rubber substrate to contain an hydroxyl terminated polybutadiene polyol. The method is practiced by first applying to a cleaned, cured rubber surface containing the polybutadiene polyol a coating of cyanuric acid followed by an additional coating of a phenol formaldehyde resin and then applying a liquid polyurethane reaction mixture which is cured to form the resultant composite. The invention is particularly directed to the preparation of a tire comprised of a polyurethane carcass applied to a cured rubber tread and to a tire comprised of a polyurethane tread applied to a cured rubber carcass.

Abstract: A mold release agent comprising metallic soaps of the fatty acids in combination with 0.03 to one percent of a polyurethane catalyst selected from secondary and tertiary amines and organic tin compounds.

Abstract: A polyurethane reaction mixture mold release comprising 1 to 5 percent by weight of a sodium or potassium soap of a carboxylic acid of 11 to 22 carbons in a diluent of alcohol or water, the mold release being applied to a mold, then addition of a polyurethane reaction mixture to form a shaped polyurethane of the microcellular type, stripping the shaped article from the mold, flushing with water at 40.degree. to 95.degree.C., drying, applying a paint coat of 3 to 10 mils over the polyurethane article to obtain a polyurethane decorative article having a paint coat resistant to peeling.