ABS Pellets: Styrene and Acrylonitrile Grafted onto Polybutadiene Latex

ABS is a tough plastic made of acrylonitrile, butadiene and styrene. Calvert's Borg-Warner patent (US 3,238,275, filed 1953) makes it in one vessel: first butadiene is polymerised to a rubber latex in soapy water at 30 °C, then styrene and acrylonitrile are added and polymerised onto the rubber at 50 °C. The latex is curdled with dilute acid, and the white granules are washed and dried. Calvert stabilised the latex with an antioxidant we do not make yet; it is left out here. Extruding into pellets is our step. The picture: our diagram.