Lead Stearate: Litharge Dissolved in Molten Stearic Acid

Lead stearate is a lead soap used to stabilise and lubricate rigid PVC. Henkel's melt process (US 4,744,927, 1988) needs no water: litharge (lead oxide) dissolves in molten stearic acid at 150 °C. The patent then adds more litharge to make a basic salt; here we stop at its first stage, the neutral salt (two parts acid to one of lead oxide, by moles). Lead compounds are poisonous: no dust, no eating, wash well. The picture: our diagram.