Synthetic resins and their raw materials / A survey of the types and uses of synthetic resins, the organization of the industry, and the trade in resins and raw materials, with particular references to factors essential to tariff consideration. Under the general provisions of section 332, title III, part II, Tariff act of 1930.

by United States Tariff Commission

Source: Analyses of invoices of paragraph 28, act of 1930—U. S. Tariff Commission.

With the more advanced development of polystyrol resins in Germany prior to 1938, evidenced by larger commercial production, by wider application, by the marketing of a water-white product at a considerably lower price, it might be expected that imports into the United States would have been in considerably larger amount than shown in table [9]. That they were small was probably due to the high rate of duty which made them expensive as compared with other synthetic resins in the United States and thus limited their market to uses in which the others were less satisfactory. Resoglas was reported to have been selling for 40 cents per pound in Germany. The imported resin is assessed for duty under the provisions of paragraph 28 of the Tariff Act of 1930 at 45 percent ad valorem based on American selling price (as a competitive product) and 7 cents per pound. The American selling price of the resin made in the United States until late in 1937, as determined by the Bureau of Customs, Treasury Department, was $1.85 per pound. The duty was therefore 90 cents per pound. Imports of Trolitul were valued at 75 cents per pound, giving a cost of $1.75 per pound laid down, duty paid, in domestic markets. With the present American selling price of 72 cents per pound, the duty would be approximately 36 cents per pound.

10. VINYL RESINS

Vinyl acetate, vinyl chloride, and to a lesser extent vinyl chloroacetate, are the raw materials (monomers) for the several vinyl resins commercially produced in the United States, Canada, and Germany. These are all esters of the hypothetical vinyl alcohol and are made by the action of acetic and hydrochloric acids on acetylene.

The spontaneous polymerization of vinyl derivatives has been known for many years, although its significance and industrial application have been realized only recently. Vinyl acetate, probably the most important of the vinyl esters, was discovered in 1912 and first made in Canada in 1917.

Vinyl resins may be classified into (a) polyvinyl acetate, (b) copolymers of vinyl acetate and vinyl chloride, (c) polyvinyl chloride, and (d) polyvinyl chloroacetate.

Description and uses.

Polyvinyl acetate resins.—The several commercial types of vinyl acetate resins are marketed under the trade names Vinyloid A, Alvar, Gelva, Formvar, and Mowilith. The first of these is a product of Carbide and Carbon Chemicals Co., New York, the next three are products of Shawinigan Chemicals Limited, Shawinigan Falls, Canada, and the last is made by the Interessen Gemeinschaft Industrie A. G., Germany. Vinyloid A and Gelva represent the simplest series of vinyl acetate resins and are made by polymerizing the monomer. The softening point and viscosity of the polyvinyl acetate resins increase with higher polymerization. Such resins are colorless, tasteless, odorless, thermoplastic products. They are soluble in coal-tar solvents and are compatible with certain alkyd resins, tar-acid resins, and natural resins. Films of polyvinyl acetate resin are not discolored by exposure, and after irradiation they become opaque to ultraviolet light, are hard and tough, and have good adherence and endurance. Their dielectric strength is good and they do not show a carbon track after the passage of an electric arc. Various grades having softening points from 80° to 200° C. are available.

Polyvinyl acetate resins are used in making transparent papers, paper to metal laminations, glassine papers for food packaging, as a substitute for chicle in chewing gum, and as a component of paints, varnishes, and lacquers. They have the desirable properties of compatibility, durability, resistance to abrasion, and rust inhibition in the surface-coating use. Having the same refractive index as pyrex glass, they leave no line of demarcation when used as a cement for that material. They have been used to stiffen toe-caps in shoes and articles made from paper pulp suspensions. Gelvas are not molded as such because of their tendency to cold flow. They are used, however, as a binder for ground mineral fillers in advertising signs and for wood flour in molded artificial wood carvings. In nitrocellulose lacquers they improve the adhesion, luster, and toughness.