These days, plastics are most commonly manufactured from petrochemical derivatives, but the earliest plastics were developed using natural products, as early as the 1850s. The first man-made plastic was Parkesine, developed by Alexander Parkes and patented in the United Kingdom in 1856. Parkesine is made from cellulose (a plant starch) and nitric acid, which is then dissolved in alcohol and hardened.
Some sixty years later, it was a Whanganui-based company that led development of the plastics industry in both New Zealand and Australia, based on casein, a protein found in milk. Whole milk contains around 12% solids, of which some 3% is casein.
The New Zealand Casein Company was entirely new so far as Australasia was concerned when company owner and entrepreneur F W Vickerman established the first experimental casein production plant at Whangaehu in 1911. During the first year of operation the company produced 60 tonnes of casein.
By January 1912, two further plants were in progress in addition to the initial one at Whangaehu, and the company had also begun building a large central drying factory in Kelvin Street, Aramoho, with capacity for six tonnes of casein to be produced each day. The company had an arrangement to dry milk supplied by the Cooperative Dairy Factory at Bunnythorpe, and negotiations were also well-advanced to process milk from several Taranaki dairy factories.
The Aramoho factory was designed by W R Mayes, built by W James and cost £5,000 to construct. Chairman of Directors was H E Good and Vickerman was manager.
At the Aramoho plant an extraction shed housed vats, strainers, presses, and troughs. The main building contained a coal store with capacity for 100 tonnes of coal, a boiler room equipped with a Babcock boiler of the latest type, an engine room with a twelve horsepower engine to drive the machinery, and a dynamo for electric lighting.
As a result of the success of the Wanganui operations, Vickerman made an application to patent attorneys Baldwin and Raynard of Wellington for a casein drying apparatus in October 1912.
Casein has a multitude of uses, including as a cold-water paint, and making imitation ivory and bone for knife handles, buttons, combs, telegraph insulators, billiard balls and piano keys. Casein was favoured by plywood manufacturers and cabinetmakers as a superior waterproof and hard-setting glue. It was also an additive in biscuit manufacture. And by 1916, casein was used in the manufacture of aeroplane wings. By 1917, casein was mainly used to produce a fine white surface on high quality writing paper.
Before World War I, German manufacturers were the principal purchasers of casein from Whanganui. Casein products were then on-sold to Britain, and as a result, Britain believed the product was German. The casein market suffered a significant slump following the outbreak of the war. During 1914 Mr Vickerman became convinced that if British manufacturers could only be induced to trial his casein, there would be no difficulty securing repeat orders. He arranged a ten-tonne shipment to Britain to be given away for experimental purposes, and as expected, this led to new orders and increasing demand. By 1915, 200 tonnes of casein were shipped abroad and demand was considerably in excess of supplies. In 1917 it was reported that the factory at Aramoho was unable to meet demand and casein was selling for around £70 a tonne (three times higher than the price in 1912).
It is difficult to determine when the Wanganui Casein Factory closed down through lack of available records or archives, although it is thought to have still been in operation in 1930. A search for photographs of the factory has also proved fruitless as has information about the main players such as Vickerman. If anyone can help with images or information, please contact the Curator on 06 349 1110 or email@example.com.
Casein is still produced today, mainly for bodybuilding products, and as a food additive to, for example, stiffen cream from aerosol dispensers.
To make casein
Whole milk is initially separated to produce skim milk, which is then poured into a vat and mixed with a precipitating agent (usually sulphuric or acetic acid).This separates the milk into curds (semi-solid) and whey (a watery compound).There was some concern that calves fed on the remaining skimmed milk might suffer nutritionally, and so phosphate of lime was added to remedy this problem. The casein curds are then pressed to produce hard, dry cheese-like blocks. These blocks are crushed and spread on screens which are run through drying tunnels. After baking, the granulated casein is graded according to quality and bagged for shipment. Formalin is later added to re-liquefy the casein crystals for moulding.
Karen Wrigglesworth is a Whanganui engineer, writer and a research volunteer at the Whanganui Regional Museum.