Natural rubber consumption

The balance between natural rubber and SBR is a delicate one. Natural rubber has made a comeback and reversed its downward trend. Developments of rubber farming have raised the yield from 500 Ib/acre/yr to 2,000-3,000. Petrochemical shortages and price increases have hurt SBR. Finally, the trend toward radial-ply tires, which contain a higher proportion of natural rubber, favors this comeback. Fig 18.1 shows the U.S. natural rubber consumption trends vs. U.S. SBR production, where this bounceback of the natural rubber market is very evident from 1980 to the present. The competitive price structure for these two elastomers through the years has been very evident, and their prices are never too far apart. 

World rubber usage of around 25.8 million metric tons is split between natural rubber, which constitutes about 43% of global consumption, and synthetic rubber, of which styrene-butadiene rubber (SBR) accounts for 21%. The balance of synthetic rubbers (36%) consists of polybutadiene rubber (BR) and a range of specialty polymers such as polyurethanes, halogenated polymers, silicones, and acrylates. Traditionally, the growth of synthetic and natural rubber consumption is virtually in line with the change in gross domestic product of, collectively. North America, Europe, Japan, China, and India. 

Global natural rubber consumption is split among tires (75%), automotive mechanical products (5%), nonautomotive mechanical products (10%), and miscellaneous applications such as medical and health-related products (10%). Since the 1960s, the quality and consistency of natural rubber has improved, primarily because of the implementation of standard specifications defining a range of grades of rubber. Natural rubber is available in three basic types technically specified rubbers, visually inspected rubbers, and specialty rubbers. 

Both NR and SR are traded in a dry and in a liquid form. The elastomer market (Table 9.5.1) is divided into three major zones (USA, Europe and Southeast Asia) each of which has its own dynamics very closely linked to its internal growth. In the years 2006-2007 China increased its synthetic rubber consumption (-1-19.3%) more quickly than its natural rubber consumption... 

During 2001, the world s natural rubber consumption was 7.07 million metric tons and 75% of it was... 

In the 1990s, natural rubber consumption exceeded 4 million metric tons while synthetic rubber consumption exceeded 7 million metric tons. Among synthetic rubbers the largest production was of SBR, polybutadiene, and ethylene-propylene. Production has been continually increasing in the 2000s. 

About 70% of natural rubber consumption goes into tire production while the remaining 30% is used by the nontire sector. There is some substitutability of various synthetic elastomers for natural rubber, but it is rather limited. This substitutability is restricted for the tire sector, which globally uses almost half of its total rubber requirement as natural rubber. In the short term, it is technically very difHcult to make major substitutions of synthetic rubber for NR use. Some applications are very critical, such as the use of NR in wire adhesion compounds for the production of steel-belted radial tires. Also, the use of natural rubber is very critical in the production of very large off-the-road tires. However, the natural rubber requirements of the nontire sector were only 29% of its total rubber usage in the year 2000. The nontire sector only used about 22% of its total rubber requirement as natural rubber in 2010. Many times it is easier in the nontire sector to substitute specialty syn-... 

In the 1970s there was no argument that, in tonnage terms, SBR was the world s most important rubber. At that time about half of the total global consumption of rubber of about 8 X 10 tonnes per annum was accounted for by SBR. Today natural rubber has about half the market, which has now grown to about 11 X 10 tonnes, and the share of SBR has fallen to about 24%. Nevertheless SBR remains a material of great importance. 

In 1994, the worldwide consumption of rubber was approximately 14.5 million tons a year, of which about 40% consisted of natural rubber. Natural rubber is produced as latex by tropical rubber trees (Hevea brasiliensis). It is processed locally and therefore the quality of natural rubber fluctuates remarkably [ 140]. Due to increasing demand for rubbers, combined with a decreasing production capacity in Asia and a vast increase in labor costs, the price of natural rubber is still rising sharply. In 1990-1994, the average price of natural rubber was about 0.38 /lb, while in 1996 it was already over 0.80 /lb. The remaining 60% of the articles were manufactured from synthetic petroleum-based rubbers such as isoprene rubber, styrene-butadiene rubber, chloroprene rubber and polyurethanes. The quality of synthetic rubbers is constant, and their price varies between 2 and 5 US per kilogram [137-140]. 

The requirements in 1951 (31) for the United States of America, Canada, the United Kingdom, France, and the Netherlands were 1,005,804 tons of natural rubber and 761,614 tons of synthetics. On the basis of consumption the United States required 41.7% natural, Canada 65.4, United Kingdom 98.6, France 93.3, and Netherlands 98.3 on the basis of importations, Belgium and Luxemburg needed 94.1% natural, Denmark 97.8, Greece 92.4, Italy 93.6, Norway 95.9, Portugal 98.2, and Turkey 100.0. 

Table 18.1 U.S. Production of Synthetic Elastomers, Consumption of Natural Rubber...

Manufacturing (NAICS 326), Rubber Products (NAICS 3262) totals 35.3 billion, of which Tires (NAICS 32621) makes up 15.4 billion, showing the dominance of the automobile tire market in this sector of the chemical industry. The top polymer production summary in Table 1.16 gives a numerical list of important synthetic elastomers. Styrene-butadiene rubber (SBR) dominates the list at 1.93 billion lb for U.S. production. All other synthetic elastomers are much smaller. While elastomers had a slight increase in production from 1980-1990, only 0.5% annually, SBR was down 2.3% per year. From 1990-2000 it was up 1.0% per year. The fastest growing elastomer is ethylene-propylene, up 5.2% annually for 1990-2000. Table 18.1 gives a breakdown in percent production of synthetic elastomers and consumption of natural rubber in the U.S. 

By far the largest selling elastomers are SBR and natural rubber. SBR at 1.93 billion Ib/yr accounts for about 35% of the U.S. synthetic rubber market and 25% of the total rubber market. The U.S. imports about 2.2 billion lb of natural rubber per year. A distant third is polybutadiene at 1.33 billion lb. In 1940 natural rubber had 99.6% of the U.S. market. Today it has only 29%. In 1950 synthetic elastomer consumption passed natural rubber use in the U.S. Since then it has been a battle between the leading synthetic, SBR, and the natural product. It is apparent that these two polymers are veiy important. Table 18.2 summarizes and compares them by their properties. 

Figure 18.1 U.S. consumption of natural rubber vs. SBR production. Source Chemical and Engineering News and Chemical Economic Handbook)...

Beside styrene butadiene rubber (SBR), BR is the most important synthetic general-purpose rubber. BR accounts for an annual consumption of ca. 2.8 million metric tons. In terms of annual production SBR and BR are only outnumbered by natural rubber (NR) with a production of ca. 6.7 million metric tons a year [51J1. 

The largest use of natural rubber is in the manufacture of tires. Over 70 percent of its consumption is in this area. The next largest use is as latex in dipped goods, adhesives, rubber thread, and foam. These uses account for approximately another 10 percent. The remainder is used in a variety of applications such as conveyor belts, hoses, gaskets, footwear, and antivibration devices such as engine mounts. 

Nitrile rubber was invented at about the same time as SBR in the German program to find substitutes for natural rubber.56 These rubbers are copolymers of acrylonitrile-butadiene, containing from 15 to 40 percent acrylonitrile. The major applications for this material are in areas requiring oil and solvent resistance. The estimated worldwide consumption in 2003 was 303,000 metric tons.57... 

Styrene-butadiene rubber (SBR) is a random polymer made from butadiene and styrene monomers. It possesses good mechanical property, processing behavior, and can be used like natural rubber. Moreover, some properties such as wear and heat resistance, aging, and curing property are even better than in natural rubber. Styrene-butadiene rubber was the first major synthetic rubber to be produced commercially. Now it has become the most common rubber with the largest production and consumption in the synthetic rubber industry. It can be widely used in tire, adhesive tape, cables, medical instruments, and all kinds of rubberware. 

In 2005, nearly 8.6 million tons of natural rubber were produced. Of this amount, 94% was from Thailand, Malaysia, and Indonesia. The total world consumption of rubber is around 18 million tons per year with about 20% SBR (styrene butadiene... 

Natural rubber accounts for about 25% of total rubber consumption. It is produced from the Hevea brasiliensis tree, being formed by isoprene units with cis-1,4 links. Natural rubber is used in tyres and for retreading, latex, mechanical goods, etc. 

Global production and consumption of natural rubber have been growing, although not steadily, during the past decade, as is seen from Table 14.4 [20,21]. The variation in annual growth rate in production is mostly contributed by price and agro-climatic conditions. The growth in consumption also has had its influence on production as is evident from the above table. 

Table 14.4 Global production and consumption of natural rubber during 2000-10.

Tyres and related products Pneumatic tyre manufacturing dominates the rubber industry in terms of the quantity of raw rubber consumption. About 50-60% of the rubber produced in the world is used for manufacturing tyres and related items. Tyre products include pneumatic tyres and tubes, sohd tyres, t)n e flaps, retread material, and puncture repair Wts (PRKs). NR is the ideal base material for tyres for aircraft, racing cars, heavy duty vehicles such as trucks and buses, off the road vehicles, and tractors. An oil extended form of natural rubber could be used as base material for the manufacture of winter tyres [61]. 

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