2655. ------. [PIER, M., AND CHRISTMANN, F.] (Attorney General of the United States). Lubricant. United States Patent 2,421,082, May 27, 1947. Chem. Abs., vol. 41, 1947, p. 5299.

Certain polymerization products if added to lubricating oils will improve the viscosity index. These products are obtained by polymerizing compounds having a polymerizable double linkage, which, when polymerized by themselves with the aid of acid-reacting inorganic halides, yield products with over 1,000 molecular weight in admixture with cracked or dehydrogenation products of hydrocarbons or hydrocarbons obtained by synthesis from CO and H₂, if they contain unsaturated constituents. Gives 4 examples of preparation. In 1 instance 5% of the additive increases the viscosity index of an oil from 5 to 49.