Waste Rubber

The history of the recycling business worldwide has shown major changes over the past 25 years. Low oil prices once made it cheap to manufacture synthetic rubbers and there was little interest in environmental issues.

The cost of oil, a primary ingredient in tires, is at a record high, which has caused rubber prices to increase exponentially.

Environmental issues, spurred by clear and convincing evidence of global climate change, has pushed the environment to the top of the political agenda worldwide.

Today, there is an urgency to discover a way to truly recycle and reuse waste rubber, particularly tires.

In fact, the countries of Europe and many states in the United States have banned any more tires from being dumped in landfills.

The wasting of natural resources has often been found to make short time economic sense, but long-term risks are often associated with this approach.

This is especially indicative of the rubber industry.

Billions of tires now reside in landfills and illegal dumps around the world, causing pollution from the release of toxic chemicals and the potential for health risks from the breeding of mosquitoes in trapped water.

It is well known that there is concern in the US about the risk of spreading West Nile Virus, but in other countries, Malaria is a far bigger problem.

Today's steel belted radial tires contain natural rubber, synthetic rubber, carbon black, polyester and nylon fiber, steel cords for belts, and about 40 additional chemicals.

An effective recycling program needs to take into consideration this highly complex mixture. New equipment has been devised to deal with the break up of steel belted tires to allow both the rubber and the steel content to be reclaimed.

The disposal or recycling of tires differs greatly from one country to another.

Some countries add charges to the price of a new tire to cover the collection and disposal of the used tire. Countries at the other end of the spectrum often allow tires to be discarded without any organized collection service, making waste tire collection extremely difficult.

The waste from tires is far greater in volume than the waste from their manufacture.

The Rubber Manufacturers Association in the USA publishes biannually a detailed analysis of the scrap tire industry. The latest report (November 2006) provides an overview nationwide, although there are variances from state to state.


This report shows that, in the USA, the major percentage of tires are recycled to produce 'tire derived fuel' (TDF), a practice also found throughout Europe. There are concerns, however, that the process is not environmentally acceptable, due to the inevitable release of toxins into the air. Countries such as India and China also produce hundreds of millions of waste tires annually, but an analysis of their modes of disposal is not available.

Waste rubber comes from three principal sources; the largest source consisting of used tires that contain vulcanized rubber.

Other sources are waste produced during manufacturing processes and discarded rubber containing containing products such as latex examining gloves.

The first step invariably involves the cutting up of rubber waste into smaller parts. As tires get further processed, it is necessary to remove steel belts and produce steel that is free of contamination so this can be sold on the scrap metal market and reused.

Depending on the proposed use of the recycled rubber, the waste may be cut into smaller and smaller pieces as the fiber is removed.

The end product is called 'crumb rubber' which comes in various sizes, depending on the diameter of the crumbs. The higher the mesh size, the smaller the crumb. Because more grinding is required to make the higher mesh crumbs, these command a higher price.

The rubber industry has been extremely inventive when it comes to reusing this crumb rubber. By adding adhesive, it can be used as particles to make crumb rubber mats for homes, playgrounds and gyms. The crumb can also be used as filler for asphalt and used for road paving.

For the crumb rubber to be used in molded or extruded products in replacing virgin rubber compound at a lower cost, the rubber needs to be de-vulcanized.

DeLink has emerged as one of the most viable technologies to effectively carry out this purpose.

That's why DeLink, and the Green Rubber it creates, will open up a whole new level of opportunity and innovation for the rubber industry, as well as solving a number of major environmental challenges, all at the same time.