| abstract |
A method of producing integral skin polyurethane foams having densities as low as 1.0 to 3.0 lbs/ft3 and surfaces which may simulate grain leather. The mold surface is first coated with a release agent, then a skin forming agent and then the foamable polyurethane reaction mixture is cast in the coated mold. Representative examples of the skin forming agents are polyester polyether and polyhydrocarbon polyols of two to 10 hydroyxls, hydroxyl containing polymers having a hydrocarbon, polyester or polyether backbone. The above skin forming agents may be applied to the mold surface by incorporation in a suitable solvent such as a low boiling liquid hydrocarbon or ketone. Polyurethane catalysts may also be added to the film forming agent solution. Another group of film forming agents which may be used are particulate materials which have the ability to absorb at least 0.5 grams of water per gram of material. Representative examples are sodium chloride, diatomaceous earth and talc. |