USE OF PLASTICS

Nelson Evening Mail, Volume 78, 29 September 1943, Page 6

USE OF PLASTICS

NEW ZEALAND HOPES POST-WAR BUILDING Some prominence has been given recently to the possibility of using plastics in the construction of houses and other buildings in New Zealand after the war, says the "N.Z. Herald.” Suggestions have also been made that the manufacture of these materials should be considered as a new industry for the Dominion when peace returns. It is not generally realised that New Zealand already has a plastics industry to the extent that certain articles have been made here for a number of years by the hot-press process from plastic materials imported in powder form. The articles include picnic cups and other tableware, and various electrical fittings, such as lamp shades, plugs and ceiling “roses.” FAMILIES OF PLASTICS However, the manufacture of plastic materials themselves is a very different matter. Plastic belong to several families, the oldest of which are the celluloid and casein groups. Both of these have definite spheres of usefulness, but, although many improvements have been made in their manufacture, they do not offer the same possibilities as the newer compounds. Of the latter, perhaps the most important are the phenal-formaldehyde resins, commonly known by the commercial name of bakelite. Phenol-formaldehyde plastics ore used to produce laminated sheets, rods or tubes, which are built up of cloth or paper impregnated with the resins and shaped under heat and pressure. Articles so made include wal-panelling, structural components and aeroplane, telephone and radio parts. A second use is in the making of moulding powders. These are composed of powdered resin mixed with a filler, such as wood-flour, and are used to make the enormous range of bakelite articles with which everyone is familiar. MANUFACTURING DIFFICULTIES Another group comprises the ureaformaldehyde resins, which are utilised in the same ways as the phenol-formal-dehyde resins. Transporent and translucent articles in lovely colours, such as lamp shades, can be made from them. The remaining modern plastics are the vinyl and acrylic resins, the styrene plastics and nylon, the last of which is used principally for making hosiery and brush bristles. Some of these resins are more transparent than glass. So far as New Zealand is concerned, the manufacture of plastics on a commercial scale present many difficulties. It is a chemical industry, and chemical industries are almost invariably interlinked to make full use of all the products and by-products. An Auckland authority who was consulted gave his opinion that it would not be economical to attempt making even phenol, seeing that no New Zealand gasworks produced enough tar to warrant more than simple processing to obtain a small range of useful products. STRUCTURAL POSSIBILITIES In the building industry, hopes of the use of plastics centre mostly in the combination of timber and synthetic resins in various ways to produce weatherproof, vermin-proof and fire-resisting components of great lightness and strength. These may include sheets for interior and exterior walls, roof members and possibly floors, spouting, downpipes and roofing. Timber would be incorporated in them in the form of plywood or sawdust. Building construction of this sort would correspond to present aeroplane and shipbuilding practice. It was stated recently that the Fairmile patrol boats build in New Zealand had English-made frames and bulkheads of nine-ply timber impregnated with synthetic resin. The famous De Havilland Mosquito bomber is made of similar materials. It is worthy of mention that the plastic principle is already applied to New Zealand wartime building by the extensive use of asbestos-cement sheeting and roofing and by the substitution of concrete for iron in spouting and downpipes.