When the big tire manufacturers started using sustainable rubbers in 2016, it pushed the use of sustainable natural rubber (SNR) to the front of consumer consciousness. Product makers started ordering custom rubber parts in natural rubber. They then market their 'green' products to consumers stating the shoe soles, keyboard keys, or other product parts are "natural rubber."
Natural rubber is prized for its flexibility, pliability, and tensile strength. Its high wear and resistance to acids and salts has made it popular in automotive applications, especially tires. Nonetheless, uses for this rubber sourced mainly from small subsistence farmers have been limited.
Natural rubber also has its limitations. The rubber degrades with exposure to oils, as well as shows resistance to hydrocarbons, fats, greases, oxygen, and ozone. Therefore, it is not suitable for petroleum or chemical product exposure. About 70 percent of natural rubber is used in tires for vehicles, including cars and planes.
Industry associations such as the Global Platform for Sustainable Natural Rubber (GPSNR) are focused on sustainable rubber production and procurement. The most significant environmental concern among its members of tire and auto makers is deforestation. As rubber from the Asian rubber tree plant faces supply shortages, industry has an incentive to sustainably source rubber.
Longer term, the industry seeks alternatives to synthetic rubber from petroleum. Natural rubber has better performance due to several properties that synthetics have not been able to emulate. Under heat conditions, for example, natural rubber has greater resistance to tear and better flexibility. The sustainable investment sector's push for ESG goals and alternatives to fossil fuels in primary energy usage will propel these changes. A natural replacement for fossil-based rubber is biodegradable and sustainably sourced natural rubber.
Although limitations have narrowed its applications, material advances provide high potential to improve its properties. Sumitomo Rubber has introduced a natural rubber that emits less odor by suppressing lipids and proteins. Vystar has deproteinized natural rubber to produce a bioelastoplast natural rubber with improved strength and flexibility. The more environmentally friendly rubber has lower volatile emissions and metals. The use of carbon nanotubes reduces the carbon black.
These material advances will extend the use of custom rubber parts made from natural rubber. Many consumer products are advertising sustainable natural rubber as a marketing advantage. Sustainable rubber usage is increasing in medical equipment, which is a growing market for custom manufactured rubber products
Another area of intense research is rubber sourced from the guayule germplasm shrub. Cooper Tire, Pirelli, Michelin and Bridgestone are all developing tires from Guayale natural rubber.