PET Resin: Terephthalic Acid and Ethylene Glycol, Whinfield and Dickson

PET (polyethylene terephthalate) was invented by Whinfield and Dickson, whose patent (US 2,465,319, 1949) gives this first example: boil terephthalic acid in ethylene glycol until it dissolves, wash and dry the glycol ester, then heat it at 280 °C under nitrogen until it is a viscous polymer that melts at 254–255 °C and can be drawn into fibre. The melt is extruded and cut into chips (pellets) for moulding and spinning. The picture: our diagram.