Synthetic resins as substitutes.
Any new material will in the course of time be applied to the uses for which it has special advantages, displacing older materials which formerly served those purposes. The resulting product may sometimes be used in the same manner as before, or the properties of the substitute material may widen the usefulness of the finished product, or even make possible a product almost wholly new.
Before the development of molded synthetic resins, electrical plugs and sockets were usually made of porcelain or molded of marble dust and shellac. In this use substitution has been almost complete. Wall plates for electric switches and outlets were usually of brass. Today molded tar-acid or molded urea resins are substituted in part. In neither of these examples has the substituted material any important effect upon the use of the product.
An example of a substitute material widening the usefulness of the product is afforded by a new computing scale, where a molded urea resin casing (substituted for metal in the older model) has aided in decreasing the weight and has improved the appearance. Another example is the use of laminated synthetic resin coil forms in radio frequency transformers which, because of their better electrical properties at high frequencies, have aided in the design of more compact units.
Examples of synthetic resins making possible a wholly new product are more difficult to find, but the following will serve as illustrations: Cast acrylate sheets to form curved cockpit enclosures for airplanes; molded acrylate buttons for reflecting road markers; and new special coatings, which make possible the use of metal cans for preserving foods and beverages hitherto impossible to can without loss of flavor.