Dr. Joseph Cecil Patrick (1892–1965) invented America's first synthetic rubber in the early 1920s. While seeking a formulation for automotive antifreeze, he attempted to hydrolyze ethylene dichloride with sodium polysulfide. In doing so, he produced a brown, insoluble gum that later became known as Thiokol. He solved commercial production problems by inventing the suspension polymerization process, and solved compounding problems by degrading high molecular weight polymer to a low molecular weight liquid polymer. This material is one of the principal binders for rocket propellant.