SYNTHETIC RUBBER E. V. MURPHREE Standard Oil Development Company, New York, N. Y.
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UBBER is usually classified along with tin as one of the materials of strategic importance from a national standpoint for which the United States is dependent upon supplies which originate outside of the United States. Most, of the American rubber supply comes from the Far East. The importanre of rubber in a national emergency is due not so much to requirements for rubber in military equipment as to its widespread use in the American industrial setup. The American people move on rubber and use rubber in more than 30,000 different articles. The synthetic rubbers that are being produced commercially or have been announced as approaching the state of commercial plant application are neoprene, Buna-S, Perbunan, Ameripol, and Butyl rubber. All these synthetic rubbers have application for specialty uses, many of which are important from a national defense standpoint. The major interest in synthetic rubber from the standpoint of national defense is. however. for aDDlication in Droduction of tires to replace natural rubber, tie supply of which may be cut off. Buna-S is a copolymer of butadiene and styrene. This synthetic rubber is being produced and used for tires on a large scale in Germany. The application of Buna-S in tire treads has been investigated by several of the major rubber companies in this country, and in general their results indicate that this material is superior to natural rubber for this purpose. Perbunan (sometimes called Buna-N) is a copolymer of butadiene and acrylic nitrile and is equally as suitable for tires as Buna-S; in addition it is resistant to the action of oil and gasoline. The method of manufacture and equi)Cment required for producing Buna-S and Perbunan are practically identical. The United States patent ri Perbunan are now being licensed by t velopment Company and were acquired benindustrie, through exchange of patent will flow to Germany through license o f t ent rights by the Standard Oil Develop plant to produce 5 tons of Perbunan per by the Standard Oil Company of Louisi for operation about the first of the year. The Firestone Tire & Rubber Company has taken out a license for m*facture of both types of Buna rubber and is planning to erect a pl t to produce Perbunan a t Akron, Ohio. Neoprene (produced by du Pont) is an acetylene polymer containing chlorine. The production of this material is reported to be a t the present time on a scale of around 7 tons per day. Neoprene is an oil-resistant rubber and has been used to a small extent in the manufacture of tires. It is understood that du Pont is planning to expand their neoprene capacity to about 15 tons per day thelatter part of this year. The Goodrich Rubber Company recently announced a synthet,ic rubber termed “Ameripol” which is produced from butadiene and other materials not disclosed. Goodrich expects to have a commercial plant in operation a t Akron before the end of this year with a capacity of about 5 tons per day. Goodrich has produced tires of Ameripol and reports that they compare favorably with natural rubber tires. Butyl rubber has recently been announced by the Standard Oil Development Company and represents a new type of
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synthetic rubber distinct in characteristics from Buna rubbers. Ameripol, or neoprene. Butyl rubber is a development of the Esso Laboratories of the Standard Oil Development Company and has no relation to the German synthetic rubbers. The composition of Butyl rubber has not yet been announced; it is now being produced on a pilot-plant scale and is being evaluated for use in place of natural rubber in tires and other products. From the standpoint of national defense the time required for creation of suitable synthetic rubber capacity is of prime importance, It has been estimated that the facilities for replacing a substantial portion of the country’s consumption of 1800 tons of natural rubber per day could be installed within two years. For total replacement of natural rubber a somewhat longer period would undoubtedly be required. Rubber capacity can be obtained much more rapidly through the synthetic route than through planting additional natural rubber plantations at locations where the supply would be less subject to interruption than the present supply, which is located largely in the East Indies. About eight to ten years are required from the time of planting to bring a rubber plantation into production. The purchase and accumulation in the United States of rubber stocks, large enough to carry through a long war, from present plantations would require several years. It would then seem desirable, from a national defense standpoint, to proceed now with installation of a substantial capacity for synthetic rubber so that experience can be obtained on both its manufacture and use on a large scale. Cons)lCering the large investments involved for a substantial synthetic rubber capacity, and the fact that initially, will be necessary in proceeding with natural rubber is not too clear. in much lower costs than are possible in small plants producing only suojklimited supplies as may be required for specialties which the synthetic is definitely superior to the natural ber. It appears that the investment for large-scale synthetic rubber capacity is of the same order of magnitude as the investment for natural plantation rubber. The production cost of rubbers of the neoprene, Buna, or Ameripol types where the basic raw material is either acetylene or butadiene, appears to be substantially higher (even on a large scale), than the cost of producing and delivering natural rubber, which has been estimated to be in the neighborhood of 7 to 8 cents per pound. Improvement in production of raw materials, such as butadiene or acetylene, would undoubtedly bring the cost of production of these types of synthetic rubber closer to that of natural rubber. It has been stated that raw materials for Butyl rubber are produced more directly from petroleum than raw materials for other types of rubber, and the investments involved for Butyl rubber capacity and the production cost on a large scale should be somewhat lower than for the other types of synthetic rubber.
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