Cellulose nitrate, the classic in this type, begins life as cotton linters—the short fibers next to the seed in a cotton boll. Purified, the cellulose is treated with mixed nitric and sulfuric acids to produce pyroxylin. Camphor, alcohol, and color are added as desired. The mixture becomes a dough-like substance which is rolled, baked, seasoned, and polished. When heated, it may be shaped to any form desired; and it can be cut, sawed, filed, blown, rolled, planed, hammered, drilled, and turned on lathes. It may be obtained in practically every shade and hue, in transparent, translucent, opaque, and in mottled and pearl effects.
PROTEIN PLASTICS
Protein plastics date back to 1890 when Dr. Adolph Spitteler of Hamburg, Germany, set out to make a white "blackboard" for classroom use. He mixed sour milk with formaldehyde and got a casein plastic, a shiny substance from which many a modern button and buckle is made. It is possible to use soya beans, lignin from wood, coffee beans, and peanuts in making protein-type plastics.
NATURAL AND SYNTHETIC RESINS
An example of a natural resin is lac secreted by a little red insect that sucks the sap of trees and converts it into a protective covering for itself. Lac, upon being refined and dissolved in a suitable solvent, forms a shellac. Dr. Leo Baekeland in 1907 was investigating this natural process when he combined formaldehyde and phenol with the aid of a catalyst and heat. The result was a synthetic resin, the basis of the first molded phenolic plastic—the familiar substance of telephone receivers and many other objects. The commercial development of urea-formaldehyde plastics was made possible by availability not only of formaldehyde but also of synthetic urea.
Comparatively new in the field of structural materials, but significant for those who sell home furnishings, are laminated plastics, plywood, and veneers. Laminated plastics are made by treating sheets of paper or woven cloth with synthetic heat-reactive resins and subjecting built-up layers of the treated materials to heat and pressure. Such plastics also may be bonded to thin wood sheets and to metals. The resulting materials are useful for furniture and for interior decoration.
This type of material was used in decorating the Library of Congress Annex. It was extensively used on the British superliner, Queen Mary. From vinyl resins, one of the new families, comes the center of the sandwich in safety glass. The plastic interlayer is not broken by a blow but stretches, at the same time holding broken pieces of glass together and preventing flying splinters.
At the present time the varied diversity of plastics is a major asset. In the home furnishings field, whoever wants a new, strong, graceful, functional material for a new product has a wide range of materials in all color combinations from which to make a choice. For the first time, the claim may be advanced that certain limitations in furniture design have been released and that innumerable variations without changing the shape or structure of the product are possible. By the use of fascinating surfaces, textures, and colors, it is possible to create designs which, while simple, possess charm, intrinsic beauty, and distinction. The introduction of such a product to the home furnishings field brings a new competitive element.