If ICI Australia was to benefit from patent protection during the difficult early years of manufacture, there was no time to be lost in the mid fifties. ICI Australia sought, and obtained, an extension of the basic patent on the basis of profits lost during the war years. There was, however, no adequate petrochemical source of ethylene available in Australia at the time. Initially, the only expensive alternative was to produce it by 'cracking' (dehydration) of ethanol. Later ethylene became available from the Shell refinery, but the quantities available did not match the rate of polythene growth. Yet the decision to enter the field had to be made. In 1957, ICI brought the first polythene plant on line. It was a complex continuous polymerisation of a highly explosive gas, ethylene, at 200 atmospheres and 200°C with recycle systems, high pressure compressors, valves, and reactors, and extraordinary safety precautions. Yet, the process came on line on time, within specification and close to cost estimates.

While the launch of polythene itself was essentially a feat of technology transfer and engineering, the preparation of the market involved substantial research and technical service. Thus e.g. polythene film made by overseas formulations did not stand up to Australian ultraviolet irradiation; UV absorbent additives had to be invented and developed as well as formulations for plastic pipes, and a variety of polythene grades for different purposes (Fig. 25). Much of this work was done on imported polymer, in preparation of the market. Once these grades were established, they had to be matched by the local plant. Operating conditions of the continuous reactor had to be defined for grade after grade -reproducibly. It clearly was a new phase of chemical sophistication.

25 Laying a polyethylene coated cable across the Tasman.

Australian Academy of Technological Sciences and Engineering