Bisphenol Epoxy Resin: Bisphenol A and Epichlorohydrin in Caustic Soda, Wiles and Newey 1950

Bisphenol A dissolved in caustic soda solution and stirred with epichlorohydrin warms itself to 70 °C; two more portions of caustic soda and heat to 95 °C finish the reaction, and a taffy-like resin separates from the water (Wiles and Newey, Shell, US 2,528,932, 1950: "Epoxy Resin II", softening at 43 °C). Washed neutral and dried at 130 °C, it is the resin half of the two-part epoxy glue. The picture: our diagram of the kettle stages.