Rubber WILLIAM F. TULEY Naugatuck Chemical Division, U. S. Rubber Co. Naugatuck, Conn.
INTENSIFIED
competition
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producers of general-purpose styrene-butadiene synthetic rubber has been the dominating feature of 1958. A lower level of consumption of new rubber during the first three quarters of the year and increased production capacity in the polymer plants resulted in a considerable excess of potential supply in relation to demand. Prices for standard grades held at the levels in effect in 1955 when the government facilities were sold. Producers' costs have probably slightly increased in 1958. Increased operating costs and the higher cost for the new added capacity not yet fully productive have been only partly offset by increased efficiency and lower prices for styrene and butadiene. Synthetic general-purpose rubber consumption and production both declined in the first 9 months of 1958 as compared with 1957, but were increasing toward the end of the year. Totals in 1958 are expected to be not much below 1957. The ratio of all synthetic rubber to total new rubber consumed increased slightly to 64.22% for the first 8 months compared to 62.88% for the same period in 1957. Natural rubber prices were in a narrow range of 25.5 to 27.7 cents per pound for first grade smoked sheets in the early part of 1958 with firming prices in the range of 30 cents toward the fourth quarter. This compares with 24.1 cents per pound for the most widely used general-purpose grades ofSBR. The pattern of 60 to 6 5 % of synthetic rubber now seems so firmly established that any wide deviation from this pattern is unlikely, unless the price or supply situation changes very radically from that which has prevailed during the past several years. Manufacturers of rubber products seem less inclined to change
their use pattern with changing natural rubber prices than they were in some past periods. First Expansion Phase Completed
The expansion programs undertaken in 1955-6 have been largely completed. Capacity of SBR polymer plants is estimated for 1958 at 1,250,000 long tons compared to 857,000 long tons in 1955 when the plants were sold to private industry, an increase of 4 5 % . There is considerable uncertainty in the current capacity estimates because of the large increase in the production of oil-extended rubbers and of carbon black masterbatches. In some cases gross plant output is limited by finishing capacity rather than polymerization capacity, and net polymer production is restricted by the oil or black additions. Also, the oil content is sometimes counted as rubber. Product mix is therefore an important factor in estimating plant capacities. There has been an even greater increase in the capacity for styrene and butadiene monomers. Synthetic rubber takes only about one third of the styrene capacity, estimated at 675,000 short tons for the end of 1958. Three new butadiene producers and expansion of the older plants have added 380,000 short tons of capacity since 1955, an increase of 5 3 % , bringing the total at the end of 1958 to 1,193,000 short tons. Only about 1 2 % of the butadiene goes to uses outside the synthetic industry. Butadiene producers have a serious overcapacity situation. Industry operations were down to 5 6 % of capacity in early 1958 but have improved considerably in the last half. Synthetic rubber producers arc optimistic about the future, although further substantial increased capacity may not be needed for several years. Increased consumption is ex-
pected to bring the supply-demand situation in balance by 1963 or at least by 1965. In such a complex and changing industry, it is never practical for all units to operate at their full annual capacity. Overseas Growth of Synthetic Rubber
Increased usage of SBR by Western European countries has been accompanied by a notable increase in European production capacity for styrene-butadiene copolymers. T h e 1958 capacity in West Germany's two plants is reported at 55,000 long tons per year. The International Synthetic Rubber Corp., Southampton, England, approaching full operation in the last quarter of 1958, is reported to have a design capacity of 75,000 long tons per year. T h e Italian plant on Ente Nazionale Idrocarburi at Ravenna will have a capacity of 30,000 to 40,000 long tons per year. New plants for SBR-type rubber are reported in the planning stage in France, Holland, Spain, Brazil, India and Japan. East Germany capacity has a reported goal of 100,000 long tons per year by 1960. The special-purpose synthetics are also growing overseas. T h e French butyl plant of 20,000 long tons per year was scheduled for operation in late 1958. New nitrile rubber capacity is operating in Great Britain, and Du Pont has a neoprene plant nearing completion in Londonderry, North Ireland. This great world-wide expansion of synthetic rubber poses questions V O L 5 1 , NO. 1 ·
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63 A
I/EC ANNUAL REVIEW as to what has prompted this growth and what will be its future effect on export sales by United States and Canadian producers. A basic factor in the world-wide development of synthetic rubber production facilities is the demonstrated competitive strength of the United States industry since the sale of the plants to private industry in early 1955. Maintenance of prices at a steady level and the large investment made for a 4 5 % increase in capacity in the formerly government-owned plants proved the confidence in its future. Another strong factor has been the desire of manufacturers of rubber products outside United States and Canada to have more synthetic available to them because of its superior performance in tires and many other products. The third important factor has been the forecast increase in total new rubber requirements and recognition that natural rubber supplies would be neither adequate nor dependable to provide the forecast increase. A fourth factor is the natural desire of all highly industrialized nations to participate in this world-wide growth of synthetic rubber. Exports from the United States are likely to fall in the years immediately ahead. The 1957 exports of all types of synthetic rubbers from the United States were 203,000 long tons, an increase of 3 6 % over 1956. The 1958 exports may show no increase over 1957 as European production is increasing. This is causing some concern to United States producers with excess, idle capacity. Shifting Use Pattern in 1958
Significant trends noted in 1958 are the increased use of nonstaining types of SBR and increased demand for carbon black masterbatch and oil-extended grades. Producers have met these demands with improved products. Color standards for nonstaining grades have been improved, particularly in the nonstaining oil-extended types. The tire industry has established the advantages and good performance with increased use of the types containing 25 and 37.5% of extender 64 A
1958
oil. Several producers are now supplying polymers extended with 50% of oil. This has been made possible by improved technology for making the higher molecular weight gel-free polymer suitable for the higher oil content. Black masterbatched SBR seems to be in a new cycle of increased use. The percentage of SBR polymer consumed as black masterbatch, 1 3 % in 1953, had declined to 7.2% by 1957. In January 1958, it was only 5.0%; but a steady increase during the year had brought this up to 14.3% by September 1958. The current increase seems to be the result of improvements in the quality of present production and in the economics of purchase cost and economies in use. Several producers of black masterbatched SBR are emphasizing the improved quality resulting from new techniques by which the black is incorporated in the synthetic latex without the use of added quantities of dispersing agent needed when the black is first prepared as a separate dispersion. Improved processing qualities and abrasion resistance are claimed for the new process. Production of the regular "hot" grades (polymerized at 50° C.) continued to decline as a percentage to total production. The 1958 percentage is not yet available, but was 19.7% in 1957, 23.7% in 1956, and 27.4% in 1955. 1958 N e w Developments
Several producers are now offering the 85/15 styrene-butadiene reinforcing resin in a concentrated SBR masterbatch for easier handling and processing. An oil-extended grade is also available. Poly (vinyl chloride)nitrile rubber blends have been given much more attention as a result of products better designed for weathering resistance, oil and chemical resistance, and improved physical properties. Brominated and chlorinated butyl rubber has been available for development work, and commercial production of the latter is expected late in 1959. Improved butyl latex has been available. Both developments have aided in developing butyl automobile tires, but the performance and economy of butyl tires were
INDUSTRIAL AND ENGINEERING CHEMISTRY
still unresolved questions in 1958. A liquid neoprene provided a new form of polychloroprene suitable for putties, caulking compounds, and surface coatings. Silicone-type polymers containing fluorine or vinyl groups have more reactivity for cross linking and resultant better physical properties are expected to show the greatest growth in the future. The 4,000,000 pounds of silicone rubber production in 1957 is expected to reach 7,000,000 to 9,000,000 in 1959. The growth of polyurethane rubbers as liquids or solids for conversion to foam or solid products has been retarded by technical difficulties which are gradually being overcome. Further progress may put them back on the path of rapid growth more optimistically forecast earlier. Stereospecific hydrocarbon polymers resulting from the various heterogeneous polymerization processes continue to be a major research and development area. There have been further confirmations that the performance of "synthetic natural" (m-polyisoprene) rubber is equal or superior to natural rubber in tires. Large-scale pilot plants have been put into operation for production of these rubbers. A major economic difficulty is the cost and nonavailability of a supply of the required high purity isoprene. «i-Polybutadiene is getting more attention because the monomer is available at low cost in quantity if not purity. It has not so far closely duplicated natural rubber, but it has been proposed that it might replace up to 50% of the natural rubber in heavy-duty tires, thus greatly increasing the share of synthetic in the total rubber consumption. Synthetic elastomers are an active and productive area for research and new product development. Both producers and consumers must continually be alert to changes in technology and materials which affect their industry. In the current changes, the manufacturers of rubber products are finding increased overlapping with plastics, and sometimes it is difficult to make a distinction in processes and products. The close relationship of the science and technology of synthetic elastomers and of plastics is becoming more widely recognized in both industry and the scientific fields.
