Patent ID: 8722753

Claim:
A method of making a flexible polyurethane, the method comprising: providing B-side reactants comprising a hydroxyl terminated precursor, the hydroxyl terminated precursor being made by providing a vegetable oil-polyol mixture of modified vegetable oil containing about two or more hydroxyl groups per molecule and a polyether polyol having about two or more hydroxyl groups per molecule at a temperature of at least about 25 degrees Celsius and at a pressure of about 1 atmosphere, the mixture having a hydroxyl equivalent ratio of about 1:1 vegetable oil to polyol, and mixing a first isocyanate containing about two or more isocyanato groups per molecule at a temperature of about 25 degrees Celsius and at a pressure of up to about 1 atmosphere with the vegetable oil-polyol mixture at a molar equivalent ratio of at least 2:1 vegetable oil-polyol mixture to first isocyanate to react the isocyanate with the mixture for at least 10 minutes to form the hydroxyl terminated precursor; and reacting the hydroxyl terminated precursor with A-side reactants comprising a second isocyanate to form a flexible polyurethane, wherein the weight ratio of the isocyanate content of the A-side reactants in equivalent units is between about 60:100 and 100:80 to the active hydrogen content in equivalent units in the B-side reactants.