Mould for blow-moulded Tango plastic drinks bottles, c 1997.
© Science Museum / Science & Society Picture Library
A hollow tube of plastic with one closed end is put into a stainles steel mould and this is closed around it. Compresed air blows the tube up like a balloon until it touches the inside surface of the mould. As the plastic hardens it takes up the shape and markings on the inside surface of the mould. When the mould opens, the finished bottle is removed. Made by ICI Chemicals and Polymers Ltd.