Nontire applications

In the 1960s, anionic polymerized solutron SBR (SSBR) began to challenge emulsion SBR in the automotive tire market. Organolithium compounds allow control of the butadiene microstructure, not possible with ESBR. Because this type of chain polymerization takes place without a termination step, an easy synthesis of block polymers is available, whereby glassy (polystyrene) and rubbery (polybutadicnc) segments can be combined in the same molecule. These thermoplastic elastomers (TPE) have found use ill nontire applications. 

The portion of polybutadiene going into nontire applications continues to increase. Between 1980 and 1999, the portion of polybutadiene consumed in tire... 

In nontire applications, there has been a faster growth in the use of synthetic rubbers such as ethylene-propylene-diene monomer (EPDM) and nitrile rubbers, as a substitute for SBR. However, nontire uses for SBR are growing with applications including conveyor belts, gaskets, floor tiles, footwear, and adhesives. 

General-purpose elastomers represent the work horse rubbers of the rubber industry. They are the lowest cost, most cost-effective rubber polymers available today. The vast majority of these raw elastomers are used in the tire sector however, a large amount is also used in nontire applications as well, such as single-ply roofing, hose, dynamic parts (such as bushings, isolators, and dampers), and conveyor belts. 

Natural rubber is also widely used in nontire applications which account for approximately 30% of the consumption of all rubber as an aggregate (including both natural and synthetic rubber). However, in the nontire sector, natural rubber was about 22% of total rubber consumption in 2012. Many times natural rubber is used as the sole base elastomer in compounds used in automotive bushings, motor mounts, vibration isolators, and dampers. On the other hand, NR is blended with SBR for compounds used in conveyor belts, welding hose covers, braided water hose, laboratory tubing, footwear knee boots, footwear microcellular compounds, footwear boot uppers, tank linings, and play balls. NR/BR blended compounds are used to make conveyor belt cover stocks, shoe soling, and so on. 

With nontire applications, SBR is commonly used as the least expensive rubber choice. It is commoniy used in shoe soling by the shoe industry. It is also used in making carpet backing. Other applications include military tank pads, flooring, and... 

In the tire industry, with some less critical compounds, natural rubber can be partially substituted for SBR to a limited extent if the price of SBR rises relative to the price of natural rubber. Sometimes the same can be done in certain nontire applications as well. 

Compared to the consumption of BR in tires, the use of BR in nontire applications is relatively small. However, because of BR s excellent resiliency, it is the preferred rubber to make golf ball cores and other applications where excellent dynamic properties are needed. 

Thermoplastic elastomers (TPEs) are polymeric materials that are processed into fabricated articles in the same manner as a conventional thermoplastic, yet these articles have the properties and functional performance of a thermoset rubber. They have been gaining a significantly larger market share over the past three decades with nontire applications, compared to the conventional thermoset elastomers discussed earlier. 

Kaolin clay is basically used as an economic diluent to reduce the cost of some rubber formulations. If used at all, kaolin is typically used at 20 to 150 parts per hundred rubber. Clay is not used very much in tire applications. However, it is a common raw material for many nontire applications. 

The major use of SBR is in the production of tires, particularly passenger-car and light-truck tires, and in other automotive applications where SBR is blended with other elastomers. These applications include belts, hoses, seals, and various extruded and molded items. Nontire and nonautomotive uses of SBR are in industries that require hoses, belts, gaskets, or seals. Others include footwear (shoe soles) various kinds of solid wheels roll covers coated fabrics and electrical (wire and cable) insulation. 

The use of EPDM rubbers for the manufacture of automobile and truck tires has not been successful, mainly because of poor tire cord adhesion and poor compatibility with most other rubbers. However, EPDM rubbers have become widely accepted as a moderately heat-resisting material with good weathering, oxygen, and ozone resistance. They find extensive use in nontire automobile applications, including body and chassis parts, car bumpers, radiator and heater hoses, weatherstrips, seals, and mats. Other applications include wire and cable insulation, appliance parts, hoses, gaskets and seals, and coated fabrics. 

Clay is a widely used filler for polymer compoimds of all types including components of tires such as fiber adhesive compounds, and the entire range of nontire polymer applications where good reinforcement, moderate cost, and good processability is desired. Clays are usually added to polymer compounds at levels of 20-150 phr. The aspect ratio of clay is between 4 and 12, with average particle size ranging from 0.5 to 2.3 )um. 

Other nontire automotive applications for HR may include radiator hoses, heater hoses, weather strips and body mounts. 

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-... 

SBR is the largest volume synthetic elastomer used by the rubber industry. Also, SBR is usually the least expensive elastomer, which may explain its very wide use, especially in the tire sector. SBR usually represents about 25% of the total monetary value of all synthetic elastomers. By tonnage, SBR now represents over one-third of synthetic rubber production however, before the introduction of radial tires in the 1960s, SBR represented 55%. Not only is SBR used in tire production, it is also used in the manufacture of conveyor belts, industrial hose, and footwear, to name a few uses. About 76% of SBR is used in tires, 15% in mechanical rubber goods, 5% in nontire automotive, and about 4% in miscellaneous applications such as shoe soles, floor tiles, and adhesives. 

EPDM is the fourth highest volume general purpose elastomer used today in the ruhher industry. At 2.7 hillion pounds of global annual production in 2010, EPDM represents about 10% of the total synthetic rubber production. However, unlike NR, SBR, and BR, this synthetic rubber is mostly used in the nontire sector (only a small amount of EPDM may be used in tire white sidewall compound, cover strip, and bicycle tires). EPDM is commonly used in single-ply roofing, in automotive weatherstrips, and hundreds of other applications. 

Many of the original Monsanto/AES patents expired around 1999. As a result, there are now many new TPV suppliers offering products in competition with Santoprene. Currently there are about 15 TPV compounding suppliers in the United States alone, 10 new producers in Europe, and many new TPV firms in Asia. These new TPV suppliers are also offering new types of thermoplastic vulcanizates that are not just based on polypropylene and EPDM. In addition. Advanced Elastomer Systems (a division of ExxonMobil) expanded its Pensacola, Florida, production plant in 2006. This new capacity was needed because the projection for growth ofTPVs in the nontire sector is around 6% annually in the United States and as high as 12% for some automotive applications. 

Rutile does not chalk as much as anatase, but rutile has a slightly higher refractive index, which imparts more hiding power than anatase. Rutile is commonly used in nontire rubber applications. 

This nontire rubber industry is about 38% dependent on the automotive industry, 32% industrial, 12% construction, 12% aerospace and other transportation, and 6% other application areas. 

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