ecologicalfootprintthe passenger tire

14%

27%

28%

14-15%

16-17%

study by darrell westcott

ecological footprinttire life cycle analysis

characteristics:

production of raw material and manufacturing

distribution

in-use

collection

end of life processes

12%

1%

84%

1%

2%

natural rubber

synthetic rubber

carbon black

steel

fabric, fillers, accelerators, antiozonants, etc.

14%

27%

28%

14-15%

16-17%

ecological footprinttire characteristics

The intrinsic qualities of natural rubber make it an indispensable material for the tire industry which is responsible for consuming 70% of the worlds produc-tion of natural rubber. The base substance in rubber (latex) is collected from hevea tree.

Synthetic rubber comes in a wide variety of formulations. Elastomers derived from petroleum, improve certain tire characteristics, i.e. grip and durability.

Carbon black is the main chemical additive in tire production. It is obtained by the combustion or partial thermal decomposition of natural gases. It is used particularly for reinforcing filler as it increases resistance to normal wear and tear throughout the lifespan of the tire.

Steel is made into a small diameter wire which is then coated with a thin layer of brass which increases its tensile strength. This forms a flexible, high resis-tance cord which makes up the reinforcing structure of the casing and belt plies.

Fabric fillers are used as extra reinforcement. Most commonly used is rayon which comes from the cellulose fiber in wood.

14%

27%

28%

14%

16%

natural rubber

synthetic rubber

carbon black

steel

fabric fillers

ecological footprinttire rubber

94% of the world’s natural rubber is located in Asia

72% of the 94% comes from only three countries:Thailand / Indonesia / Malaysia

ecological footprinttire rubber

Preparation Tire Components Building and Inspection

Maxx is Ti re Pro duction Flow C har t

ecological footprinttire manufacturing

ecological footprinttire manufacturing

Tire manufacturing starts with many different kinds of raw materials, these are: chemicals, pigments, 20 different types of rubber, cord, fabric, wire. The process begins with rubber and additives like sulfur, carbon black, and solvents. The additives are combined with natural and synthetic rubber by using a large machine called a banbury. In a banbury the materials are mixed, grinded, and heated to prepare the rubber compound for the next process. The rubber comes out of the banbury as a long flat band.

There are six processes that the rubber then goes through to shape the other parts of the tire: tread, ply, belts, beads, sidewalls, and inner liner. First, tire tread is put through a tuber, mea-sured, cooled, and cut into very precise pieces. Second, the sidewalls are put through the tubers. Next, the ply is produced in what’s called a calendar mill to make large sheets that are sent to the assembly area. The tire then gets equipped with basic strength in the creel room by the placing of fine steel wire into the belts. Next, the inner liner is put in which is used to create an airtight chamber once it is placed on the vehicle. Finally, the last major part, the bead, is put in.

All the parts are then placed into a tire-making machine which constructs the tire in two stages. In the first stage, the carcass is constructed which includes the beads, plies, side-walls, and liner. In the second stage the tread and underlying belts are assembled next to the carcass.

All the parts are then placed into a tire-making machine which constructs the tire in two stages. In the first stage, the carcass is constructed which includes the beads, plies, side-walls, and liner. In the second stage the tread and underlying belts are assembled next to the carcass.

Vulcanization is the last process which transforms the newly assembled tire into a tough modern passenger tire that is built to withstand the road. Vulcanization is a process through which the tire is subjected to intense pressure and high heat internally and externally for a specific period of time. Now the tire is ready for final finish and inspection.

ecological footprinttire rubber and chemicals

Natural rubber (polyisoprene) is the most basic elastomer used in making tires.

Styrene-butadiene co-polymer (SBR) is a synthetic rubber which is often substituted in part for natural rubber based on the comparative raw material cost.

Polybutadiene is used in combination with other rubbers because of inherit low-heat build up properties.

Halobutyl rubber is used for the tubeless inner linear compounds, because of its low air permeability. The halogen atoms bond with the carcass compounds which is mostly natural rubber.

Carbon black forms the highest percentage of rubber compound. This gives the reinforcement and abrasion resistance.

Silica, used together with carbon black in high performance tires, provides a low heat build-up reinforcement.

Vulcanizing accelerators are complex organic compounds that speed up vulcanization.

Sulphur crosslinks the rubber molecules in the vulcanization process.

Zinc oxide is added as the main activator used to assist the vulcanization.

Antioxidants and antiozonants are added to prevent sidewall cracking due to the action of sunlight and ozone.

The largest percentage of a tires life cycle is when it is in use on a vehicle. During this phase, the tire has a detrimental impact on nature in the form of tire particulates left on the asphalt. These particles raise toxicity levels in nearby soils and lead to the formation of black carbon. These pollutants has been shown to cause lung toxicity and account for significant propor-tions of particulate matter in urban areas.

ecological footprinttire wear particles

Tire wear particles (TWP) are released from the tire tread as a result of the interaction between the tire and the pavement. There are three types of particles that should be defined and distinguished: • Roadway Particles (RP) - Particles on roads composed of a mixture of elements from tires, pavements, fuels, brakes, environmental ‘dust’, and the atmosphere • Tire Wear Particles (TWP) - Particles produced by the interaction between tires and pavement • Tire Particles (TP) - Particles of pure tire tread rubber, e.g. cryogenic (frozen) grinding

The solution of undiluted 50 g/L TWP produced 80.2% mortality in X. laevis embryos and this toxic effect was three times greater than that produced by 100 g/L TWP. Zinc accumulation in HepG2 cells was evident after 4 hours of exposure. A549 cells exposed to TWP organic extract for 72 hours presented a modified morphology, a decrease in cell proliferation and an increase in DNA damage as shown by comet assay.

A: from tire

C: from environmental “dust”, brakes, fuels, and atmosphere

B: from pavement

RP (A+B+C)= All particles on the road= Roadway Particles

TWP (A+B)= Particles from wear

= Tire Wear Particles

TP (A)= Particles from tire= Tire Particles

ecological footprinttire wear particles

In 2003, markets for scrap tires were consuming 233 million, or 80.4 %, of the 290 million annually generated scrap tires:

- 130 million (44.7%) are used as fuel - 56 million (19.4%) are recycled or used in civil engineering projects - 18 million (7.8%) are converted into ground rubber and recycled into products - 12 million (4.3%) are converted into ground rubber and used in rubber-modified asphalt - 9 million (3.1%) are exported* - 6.5 million (2.0 %) are recycled into cut/stamped/punched products - 3 million (1.7%) are used in agricultural and miscellaneous uses Another 16.5 million scrap tires are retreaded. After any retreading has been performed, 290 million scrap tires are generated. About 27 million scrap tires (9.3%) are estimated to be disposed of in landfills. (Source: Rubber Manufacturers Association, 2004.)

material recovery

retreading

6%

25%

24%energy recovery24%

dumped/ unreported11%

exportation reuse

ecological footprintscrap tires

ground

shredded

whole

in asphalt for paving streets and highways

as low weight, high volume fill for septic systems

as playground cover

as drainage and fill materials in highway applications

as fill material for turf grass

in molded goods

scrap tires can be used:

scrap tires can be used:

scrap tires can be used:

as mulch in flower beds

as landfill liners and daily covers

in retaining walls

in embankments

as artificial reefs and breakwaters

ecological footprintreuse + recycle

ecological footprintreuse + recycle

The end of the life of a tire is equivalent to the amount of heat energy in good-quality coal. Approximately one ton of tires yields the same energy as .7 tons of oil. The low level of sulfur contained within tires can make them a good substitute for fuel with a less environmental impact than certain types of coal.

Tire derived fuel is used in the US and Japan in: power stations, electricity production, indus-trial boilers, steam production, and used in incinerator units.

Though tires seem to be doing well as a secondary fuel source, energy recovery has shown to cause substantial reductions in some pollutants such as nitrogen oxide, but has an increase in other pollutants during its process.

Although there are many different techniques in recycling and reusing tires, almost a quarter of end-of-life tires still end up in landfills. Whole tires in landfills are detrimental because of uneven settlement and the tendency for tires to rise to the surface. The impacts destroy the landfill liners increasing the potential of toxic agents to leak into the surrounding environment.

It is essential to have disposal regulations for tires to cut down all of the negative impacts that can arise from careless disposal.

ecological footprintend of life regulations

http://www.clemson.edu/ces/arts/potentialuses.html

http://www.epa.gov/osw/conserve/materials/tires/index.htm

http://www.libertytire.com/Home.aspx

http://www.moderntirect.com

http://www.nokiantires.com

http://www.particleandfibretoxicology.com/content/2/1/1

http://www.wbcsd.org/web/projects/tire/InterimReportonTireWearParticleresearch.pdf

ecological footprintbibliography