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Uses
The main uses of natural rubber (NR)
NR and synthetic rubber (SR) in tires
Latex products
Because of its elasticity, resilience, and toughness, natural rubber (NR) is the basic constituent of many products used in the transportation, industrial, consumer, hygienic and medical sectors.
Of these major end-use markets for rubber, transportation is by far the largest single sector, with tyres and tyre products accounting alone for over 50% of NR consumption. Truck and bus tires would represent the largest single outlet for NR, followed by automobile tires.
General rubber goods for commercial and industrial use account for the balance. These non-tyre rubber items include industrial products (for example, transmission and elevator belts, hoses and tubes, industrial lining, and bridge bearings); consumer products (like golf or football balls and other recreational and sports goods, erasers, footwear and other apparel); and articles for use in the medical and health sector (notably, condoms, catheters and surgical gloves) as well as seismic materials (for instance, over 500 and 2,500 buildings are respectively fitted with seismic rubber bearings in China and Japan). Latex articles (typically condoms, gloves, threads, adhesives, and moulded foams) could be included in different categories in terms of end-use.
NR major end uses
Source: UNCTAD secretariat
Growth in demand for certain end products conventionally using rubber does not necessarily translates into growth of NR consumption, owing to competition from synthetic rubber (SR) and new materials.
Despite the competition of synthetic compounds, natural rubber continues to hold an important place in tire consumption. In particular, its superior tear strength and excellent resistance to heat up makes it better suited for high-performance tires used on racing cars, trucks and buses, and aircraft. In these applications, the potential for switching from natural to synthetic rubber is quite limited, given the clear-cut technological advantages to natural rubber.
Rubber tires are of two types: solid (or cushion) tires, in which the rubber portion functions to carry the load and absorb shocks; and pneumatic tires, with compressed air that fills the tire. The former are used on industrial machinery and on military vehicles; pneumatic tires are used for almost all free-moving vehicles (i.e., other than railroad cars). Pneumatic tires include tires for automobiles, trucks and buses, (motor) bicycles and airplanes and "off-the-road" tyres for special vehicles (such as construction vehicles and agricultural machinery). The distribution channel for pneumatic and solid tyres is two-tired, consisting of original equipment manufacturers (OEMs) and the replacement market.
Breakdown by major sectors (NR and SR)
Source: UNCTAD secretariat (Data: International Rubber Study Group, Statistical Bulletin)
Separate rubber compounds are used for different parts of the tire (on the weighted distribution of the various components of a passenger tires, please refer to this section of Michelin's corporate site; also, the table below).
Generally, the larger the tire the greater the share of natural rubber. The table below refers to relatively small-size truck tires.
Typical tire composition by weight
| Passenger tire | Average weight: New 25 lbs, Scrap 20 lbs.
|
| Natural rubber | 14 % |
|
Synthetic rubber |
27% |
| Carbon black | 28% |
| Steel | 14 - 15% |
| Fabric, fillers, accelerators, antiozonants, etc. | 16 - 17% |
| Truck Tire | Average weight: New 120 lbs., Scrap 100 lbs. |
| Natural rubber | 27 % |
| Synthetic rubber | 14% |
| Carbon black | 28% |
| Steel | 14 - 15% |
| Fabric, fillers, accelerators, antiozonants, etc. | 16 - 17% |
Source: Rubber Manufacturers Association (RMA)
As for high-performance tires, technical factors (performance needs of the products and process technology) also constrain the ease of substituting SR for NR in the latex product market. For example, because it is waterproof (whereas some synthetics absorb water), NR latex is best suited for use in surgical and medical examination gloves and in condoms. NR latex is possibly the best protection against pathogens such as HIV. Latex products include, inter alia, condoms, gloves, threads, adhesives, and moulded foams. They found applications, including specialty applications, in different sectors, among which is the medical and hygiene sector.
Overall, the competitive relation between natural and synthetic rubbers hinges upon a variety of related factors, which include technical factors (technical properties of the rubber, performance needs of the product, process technology), economic factors (relative input prices and processing costs), and relative efficiency of marketing channels. As in the case of contraceptives and high-performance tires, the extent to which substitution from NR to SR may take place on the basis of price is limited. It is mostly dependent on technical factors, which also determine the category and grade of elastomers used.
NR is processed in different types and grade with characteristic applications. For example, latex concentrate is the basic constituent of contraceptives, surgical dipped goods, and rubber threads. Ribbed smoked sheets are used in the industrial sector when extra tough rubber is needed (for example, for tank liners). Pale Crepe is valuable for medical sundries, footwear, cements and adhesives.
Rubber producers increasingly custom-make a wide range of special rubbers that meet customers' specifications. These rubbers are often made by means of compounding natural rubber and synthetics, which also tends to complicate the distinction between NR and SR.
