1. INTRODUCTION
This survey deals with the several commercially important types of synthetic resins covered by paragraphs 2, 11, and 28 of the Tariff Act of 1930 and with the raw materials necessary for their production. It is made under the general investigatory powers of the Tariff Commission as provided in section 332 of that act.
The field of synthetic resins is a comparatively new one, most of its commercial development having occurred within the past 10 years. In 1937 the domestic output was more than 160 million pounds as compared with slightly more than 10 million pounds in 1927.
The first important patents on synthetic resins were granted about 25 years ago. These patents covered phenolic resins probably intended for use as substitutes for certain natural resins. It was soon found that these synthetics offered possibilities of application vastly greater than the natural materials. At first progress in their application was slow as is usually the case with new products. During the World War the shortage of phenol promoted interest in the use of the other tar acids as raw materials for synthetic resins and intensive research developed resins from the cresols and higher boiling tar acids. These resins possessed properties sufficiently different from those made from phenol to establish them permanently.
In the meantime research on other types of resins was carried on in the United States and in Europe. The tar-acid resins for molding were the only commercially important ones on the market until about 1929. About that time, however, new commercial products began to appear rapidly. Cast phenolic resins became available as material for novelties of unusual brilliancy and beauty, the urea resins to meet the requirements for light colored thermosetting resins in molded articles, and the alkyd resins for use in new surface coatings which replaced conventional paint materials.
Later there followed a number of thermoplastic materials offering new and unusual properties. Vinyl resins found application in molded products and in safety glass. The acrylate resins became the nearest approach to organic glass yet developed. The polystyrene resins, long in the research stage, made their commercial appearance in 1937. Resins from petroleum, from furfural, from adipic acid, and from aniline are on the market. Many others are under investigation and some of them will undoubtedly become important.
The versatility of synthetic resins is most unusual. In various uses they have successfully displaced glass, wood, metal, hard rubber, bone, glue, cellulose plastics, protein plastics, and conventional paint materials. They compete with glass in shades and reflectors and offer properties which will increase their use for this purpose. Cases for scales, radios, and clocks, formerly of wood and metal, are now made of these synthetic resins.
This survey deals with the synthetic resins, the nature and trade in the raw materials necessary for their production, the processes by which they are made, trade in them in the United States and between nations, and the nature of the competition which they meet. It does not go into the details of manufacture of and trade in the multitude of articles made of synthetic resins but stops at the point where these materials are turned over to the resin fabricator. The synthetic resins are but one of four broad groups of organic plastics. The others—natural resins, cellulose ethers and esters, and protein plastics—are discussed herein only as they relate to or compete with the synthetic resins.
The purpose of the survey is to bring together in one publication the available information on synthetic resins so as to provide a basis for consideration of future tariff problems. Because the industries involved are comparatively young and are expanding rapidly, their present day importance is not generally realized. The rapidity with which the synthetic resin industry is developing causes any comprehensive report on the subject to be practically out of date before it can be published. Notwithstanding the progress made each year in the quantity of production, new applications, and new commercial products, the industry may be said to be still in the industrial nursery. This circumstance necessarily limits the period during which any treatment of the subject will be representative.
The scope of this report has been stated to include synthetic resins up to the point where they are further manufactured, and the raw materials used in producing them. It was also stated that natural resins and synthetic plastics other than resins, such as the cellulose compounds and modified rubber compounds, are excluded. The boundaries of these categories are therefore important.[1]
The term “resin” was formerly applied exclusively to a group of natural products, principally of vegetable origin, although at least one important resin, shellac, is of animal origin.[2]These natural resins are widely used in paints, varnishes, and lacquers for decorative and protective surface coatings. They also have extensive use in textile impregnation, adhesives, soap, paper, and in cold-molded articles. In recent years the natural resins have had to compete with synthetic products, and each gravitates toward uses which demand the quality or combination of qualities which it can most completely supply.
A resin may be defined as a semisolid or solid, complex, amorphous mixture of organic compounds with no definite melting point and no tendency to crystallize. The resins are characterized by a typical luster and a conchoidal fracture rather than by definite chemical composition. The term includes natural resins, such as colophony (ordinary rosin), copal, damar, lac, mastic, sandarac, shellac, etc., sometimes called gums or gum resins although none of them are true gums.
A synthetic resin is a resin made by synthesis from nonresinous organic compounds. The term includes materials ranging from viscous liquids to hard, infusible, amorphous solids. As a rule synthetic resins possess properties distinct from those of natural resins. The term “plastics,” sometimes applied to synthetic resins, also includes many materials which are not resins.
A plastic is anything possessing plasticity; that is, anything which can be deformed under mechanical stress without losing its coherence or its ability to keep its new form. According to this definition the term includes such materials as putty, cement, clay, glass, and metals, as well as certain modified natural or semisynthetic products, such as cellulose acetate, cellulose nitrate, and casein more commonly so designated. To speak of the plastics industries is almost meaningless because of their enormous scope, including as they do those producing cement, ceramics, confectionery and rubber, as well as those producing the semisynthetic products mentioned.
The resin industry embraces two main types of materials, thermoplastic and thermosetting. Thermoplastic materials are those which, although rigid at normal temperatures, may be deformed and molded under heat and pressure. Among such materials are the cellulose esters, acrylate resins, vinyl resins, polystyrene resins, etc. The recent development of injection molding has given thermoplastics a new significance.
Thermosetting substances are thermoplastic at some stage of their existence, but become hard, rigid, and permanently infusible upon the application of the proper heat and pressure. They are then irreversible whereas the thermoplastics are reversible. Outstanding among the thermosetting resins are tar-acid resins, urea resins, and the alkyd resins.
The earliest mention of synthetic resins in the tariff laws of the United States was the provision in group III of the Emergency Tariff Act of 1916 for a duty of 30 percent ad valorem and 5 cents per pound on synthetic phenolic resins. None of the non-coal-tar synthetic resins were specifically mentioned prior to the Tariff Act of 1930.
The Tariff Act of 1922 (par. 28) provided for synthetic phenolic resin and all resinlike products, solid, semisolid or liquid, prepared from phenol, cresol, phthalic anhydride, coumarone, indene, or from any other article or material provided for in paragraph 27 or 1549. The rate of duty was 60 percent ad valorem based on American selling price or United States value and 7 cents per pound, with a provision that the ad valorem rate should be reduced to 45 percent 2 years after the passage of the act.
The Tariff Commission made two investigations of synthetic resins under section 316 of the act of 1922. The first was undertaken April 16, 1926, upon complaints of several domestic manufacturers, of unfair methods of competition and unfair acts in the importation and sale of synthetic phenolic resin, Form C, and articles made wholly or in part therefrom, in infringement of the patent rights of the Bakelite Corporation. Following the investigation, the Commission recommended on May 25, 1927, that this material (as described under United States Patents No. 942,809 and 1,424,738)be excluded from entry into the United States. Importers appealed from the findings of the Commission to the Court of Customs Appeals, and the judicial proceedings were ended on October 13, 1930, by denial of a writ of certiorari for the Supreme Court of the United States to review the judgment of the Court of Customs and Patent Appeals. The latter court had held, among other things, that there was substantial evidence in support of each finding of the Commission. On November 26, 1930, the Treasury Department issued an order prohibiting the importation of synthetic phenolic resin, Form C, with certain exceptions. (T. D. 44411.)
The second investigation by the Tariff Commission was instituted on December 23, 1927, also under section 316 of the act of 1922. It concerned unfair methods of competition and unfair acts in the importation into the United States of laminated products of paper or other materials and insoluble, infusible condensation products of phenols and formaldehyde. The Commission recommended to the President that, until March 4, 1929, inclusive, certain products covered by United States Letters Patent Nos. 1,018,385, 1,019,406, and 1,037,719 be excluded from entry into the United States. These products were laminated cloth, paper or the like, combined with insoluble, infusible condensation products of phenols and formaldehyde. The order of the President prohibiting the importation was contained in T. D. 42801 issued June 11, 1928.
Under the Tariff Act of 1930, practically no changes were made in the provisions of paragraph 28 that concern coal-tar synthetic resins. Paragraph 2 was extended to include, among other things, the resins (polymers) of certain organic compounds. The only commercial products covered by this provision are the vinyl resins. The rate of duty was 30 percent ad valorem on foreign value and 6 cents per pound. Under the trade agreement with Canada, the duty on vinyl acetate, polymerized or unpolymerized, and on synthetic resins made in chief value therefrom was reduced to 15 percent ad valorem and 3 cents per pound (effective Jan. 1, 1936).
The Tariff Act of 1930 contains a provision, in paragraph 11, for synthetic gums and resins not specially provided for, 4 cents per pound and 30 percent ad valorem on foreign value.
The application of synthetic resins has extended into practically every branch of industry. This marked expansion is not surprising when the adaptability of these products is considered. Their uses range from jewelry and bottle closures to building materials; from adhesives and new types of surface coatings to light reflectors and shades. They are being substituted for natural materials, such as wood, metal, and glass at an increasing rate. They have provided new uses for raw materials formerly used in antiseptics, disinfectants, explosives, embalming fluids, fertilizers, moth repellants, and as solvents. The speed of expansion of their use in resin manufacture has been such as to create a serious shortage of some of these raw materials.
New applications for synthetic resins appear almost daily. They are used in furniture, wall panels, builders’ hardware, electrical fixtures, and in thousands of small appliances. The automobile industry is probably the largest single user. An interesting application hereis in silent gears and shaft bearings where the use of synthetic resins makes water lubrication possible. Other automotive uses are in distributor heads, horn buttons, gear shift knobs, dome light reflectors, control knobs and the finishing lacquers. Additional uses contemplated for the near future are in accelerator pedals and instrument panels. A new type of safety glass in which vinyl resins are used was introduced in 1936.
In decorative uses remarkable progress has been made. Panels of laminated resins are widely used in store fronts, lobbies of office buildings, and hotels; doors faced with this material are in use. The linerQueen Maryis paneled, in part, with laminated resins, as is the annex to the Library of Congress. Lamp shades of urea resin are used in many Pullman cars and are available for home and office use.
Other things being equal, the cheaper a synthetic resin, the more widely it may be applied as a substitute for other materials. As a result many an apparently useless byproduct, such as oat hulls which yield furfural, is either already used or being tested as a source of raw material. Other materials which have already found a place or may do so, are soybean meal, sugar, and certain petroleum distillates.
Each of the important groups of synthetic resins has been sponsored by one or more manufacturers of established reputation and large capital resources. When a product reaches the commercial stage, after heavy research cost, its future importance is therefore usually assured.
Most of the commercially important synthetic resins are derived directly or indirectly from coal. The chart (p. 6) shows the derivation of certain synthetic resins from the principal raw materials used in their manufacture and the intermediate products back to the original source of the material.
The polystyrene resins, for example, are made by polymerizing styrene or vinyl benzene. Although basically from ethylene and benzene, vinyl benzene may be formed in several ways. Ethylene is found in the gases from the destructive distillation of coal but is obtained commercially by cracking natural gas or petroleum. Styrene, found already formed in the light oil fractions from coal tar, causes gum-forming in motor benzol and certain industrial gases.
When coke and lime are mixed and heated in an electric furnace to 2,000° C., calcium carbide is formed. This compound with water yields acetylene, the starting point for a long list of important products, including several types of synthetic resins. When acetylene gas is passed through acetic acid (itself obtained from acetylene) vinyl acetate is obtained. If hydrochloric acid is used instead of acetic acid, vinyl chloride is obtained. These compounds, when polymerized, yield the vinyl resins. The acrylate resins may be obtained from the same basic raw material by an entirely different procedure. Synthetic rubber is also derived from acetylene, as are acetic anhydride and acetic acid (used in making cellulose acetate plastics) and many other chemicals of commercial importance.
Derivation of certain synthetic resins.
Derivation of certain synthetic resins.
When naphthalene (from coal tar) is treated with air at elevated temperatures, phthalic anhydride is formed. Substituting benzene for naphthalene yields maleic anhydride. Both of these substances when condensed with glycerin, a byproduct of the soap industry, yield alkyd resins.
The tar acids from coal tar, either separated or mixed, when condensed with formaldehyde give the highly important tar-acid resins. Or if formaldehyde is condensed with urea, obtained from carbon dioxide and ammonia, the urea resins are formed.
The chart indicates the synthetic resins which are thermoplastic, that is, which become plastic again upon reheating, and those which are thermosetting, that is, pass into an infusible stage at a certain critical temperature and pressure and do not again become plastic upon subsequent reheating.
The data used in this report were obtained from a great variety of sources. The several American and British trade journals were freely consulted as were the various text books on this subject. Much of the information on the domestic industry was obtained by personal contact with producers and by correspondence. Field work included visits to most of the domestic producers of resins and a representative group of fabricators. Information of this type which was nonconfidential or which could be combined so as not to reveal individual operations was invaluable. Even where it was such that it could not be published it became part of the general background.
The data pertaining to the industry in foreign countries were, for the most part, furnished the Tariff Commission by Department of Commerce representatives stationed abroad, in response to inquiries by the Commission.