Plastics and the Glass Industry

Abstract

IN his address to the Fifth Glass Convention held last week at Droitwich under the presidency of Mr. H. S. Williams-Thomas, Dr. V. E. Yarsleystressed the view that plastics are not to be regarded as substitutes for the older materials, glass, wood and metals. Much of the work done on the new transparent plastic materials such as the methacrylate and polystyrol products has been inspired by glass. In aircraft construction, where low weight must combine with security and good optical properties over a wide range of temperature conditions, 'organic glass' has no rival. The technique of the manipulation of these materials has progressed very considerably, but, as was brought out in discussion afterwards, not sufficiently to enable a bottle, for example, to be blown from a plastic mass in the manner in which molten glass is manipulated by fully automatic machinery. Much interest was aroused by the reference by Dr. A. Caress to the optical and other properties of materials of the ‘Perspex’ type, and Drs. W. M. Hampton and J. C. Peddle pointed out the tremendous range of optical properties furnished by the optical glass manufacturers to comply with the requirements of the instrument makers, and the need for both homogeneity and very precise annealing. It appears that as yet the only serious competition that might be feared in this field is in the manufacture of ophthalmic lenses, and mass-produced lenses of the type usedin very cheap cameras.