Rubber may not be the first thing that leaps to mind when words like 'innovation', 'bio' or possibly 'dandelion' enter the conversation. Yet rubber, too, is quietly and, in its own way, making a stir in the renewable resources discussion.
Take, for example, the recent announcement made by Versalis, a global leader in elastomers and a subsidiary of Eni, and Yulex Corporation, an agricultural-based biomaterials company. These companies are forming a strategic partnership to manufacture guayule-based bio rubber materials and will launch an industrial production complex in Southern Europe.
Guayule (Parthenium argentatum) is a native North American renewable, non-food crop that requires little water usage, no pesticides and offers an alternative source of natural rubber that can be locally produced. Also, tire company Cooper is collaborating with Yulex, on researching a tire-grade rubber from the plant.
Another tire manufacturer, Bridgestone Corp., announced last year that research had "produced promising results indicating that the Russian dandelion (Taraxacum kok-saghyz) can become a commercially viable, renewable source of high-quality, tire-grade rubber." The company also claims to have produced polyisoprene synthetic rubber from isoprene derived from biomass, a first step toward replacing petrochemical raw materials with sustainable biological raw materials in the production of synthetic rubber.
And in the Netherlands, tire manufacturer Apollo Vredestein successfully produced tires made of from natural rubber from both the Russian dandelion and from guayule. Before being taken into production, the tires will first undergo extensive testing over the coming months. The tires were developed within the scope of the EU-PEARLS project, the four-year European project, which was established precisely with the aim of developing an entire production and application chain for guayule and Russian dandelion latex and rubber in Europe.
A new supply of natural rubber
This renewed interest in 'bio' rubber might be viewed as part of the 'green' trend sweeping the chemical and polymer industry. There is, however, a far more basic reason behind the efforts to develop alternative sources of natural rubber: the demand for natural rubber currently outstrips supply. Natural rubber is a vital commodity of huge economic significance. Its importance in the transportation industry cannot be overstated: the single major global consumer of rubber is the tire industry, with large tires on aircraft, tractors and earthmoving equipment being largely made of natural rubber. However, natural rubber is also vital in a host of other industries, including construction and footwear.
Currently, the entire global supply of natural rubber comes from Southeast Asia. Hence an urgent need is felt by rubber-consuming industries around the world to develop what the EU-PEARLS consortium called "a strategic fallback option, in case current threats to Hevea rubber become reality: South American Leaf Blight, climate change, or high labor costs," to safeguard supply.
What about synthetics?
In the first quarter of the twentieth century the price of natural rubber rose, as demand accelerated. Rubber had become a major ingredient in a wide range of products, such as valves, wiring, tires, hoses and seals. Two World Wars pushed global rubber consumption to new heights as the defense industry went into overdrive to supply the needs of the military. The problem was that all major rubber production sites were located in Southeast Asia and, particularly in World War II, largely in enemy hands. This gave an enormous impetus to the development of new petroleum-based synthetic rubber grades. In the U.S. alone, synthetic rubber production jumped from 8000 tons in 1941 to 820,000 tons in 1945, in order to meet industrial needs.
By the early sixties, synthetic rubber made up 70% of the market.
Yet synthetic rubber, for all its favorable properties, cannot take the place of natural rubber in all applications. Moreover, rising oil prices have meant that the price of synthetic rubbers has also increased. Research in this area is also ongoing: Goodyear and DuPont are currently among the companies working on the development of biobased replacements for the petroleum-based ingredients of synthetic rubbers.
Rising demand, flat supply
Today, the demand for natural rubber is once again rising fast, mainly due to the rapid industrial growth and surging car ownership rates in countries like China and India. Meanwhile, supply is having a tough time keeping up. Rubber production is carried out in a limited geographic area and newly planted trees need to mature before they are ready for latex production. These factors have led to efforts on the part of countries around the world with industries that are heavily dependent on rubber, to look for alternative sources of natural, or 'bio' rubber and a more sustainable, local rubber producing process. As the examples of Cooper, Bridgestone and Apollo Vredestein show, the tire industry in particular has been at the forefront of this research.
Ironically, warnings that the supply of crude rubber could be jeopardized because of labor, geographical and political factors are nothing new. At the start of the 1900s, newspapers around the world were regularly sounding the exact same message. The early 1900s saw the first experiments in the U.S. using guayule as an alternative source of natural rubber in the United States. Rubber extraction plants in Mexico even exported guayule rubber to the U.S. during this time. In the Soviet Union, Stalin strove to lessen his country's dependency on natural rubber from the then British colonies, and set up a program to develop alternative sources of natural rubber. His scientists identified Russian Dandelion as a viable source of domestic rubber. However, as cheaper and better synthetic rubbers arrived, these attempts were ultimately abandoned.
Temporarily, as it now turns out.
Sustainable aims and economic needs produce fast results
Today, guayule and Russian dandelions are back in the news - for exactly the same reasons as a century ago. This time around, genetic engineering and agronomics are helping to improve the agricultural performance and rubber properties of these plants in projects in the U.S. and Europe. The results are extremely promising: while the first tires made from the new, locally produced bio rubbers may not yet be completely road ready, they are definitely on the way.