AKRON — Teijin Frontier Co. Ltd., Teijin Group's fibers and products converting company, has developed an "eco-friendly" tire cord made of recycled polyester fiber and using an adhesive that does not contain resorcinol formaldehyde (RF).
The new cord material is made from chemically recycled fibers, which Teijin Frontier said achieve the same levels of quality and performance — strength, fatigue resistance, dimensional stability and heat resistance — as conventional tire cords made from petroleum-derived polyester fiber, while also reducing CO2 emissions during production.
Teijin Frontier said it has developed the recycling technologies that chemically decompose polyester for conversion into a raw material that offers the equivalent purity of products derived from petroleum.
Up to now, the company said, conventional recycled materials were unable to meet the requirements for tire reinforcement, such as strength, elasticity, adhesion to rubber, fatigue resistance, dimensional stability and heat resistance, due to lower mechanical properties.
The new product also incorporates an adhesive polymer compound instead of RF, thus reducing the environmental impact of products using the material. The new compound delivers rubber/cord adhesion equal to that of conventional resorcinol-formaldehyde-latex (RFL) adhesives, which have been shown to have harmful effects on the human body.
Resorcinol — a phenol derivative chemically known as 1,3-dihydroxybenzene — has been used since the 1950s in combination with formaldehyde to improve the adhesion of organic and inorganic reinforcing materials to natural/synthetic rubber compositions.
Formaldehyde is a naturally occurring organic compound — CH2O (H-CHO) — that is used widely as a precursor to many other materials and chemical compounds. The U.S. National Toxicology Program described formaldehyde in 2011 as "known to be a human carcinogen."
Teijin Fronter claims this is the world's first commercialization of a tire cord material that combines an RF-free adhesive and a chemically recycled polyester fiber. The company plans to start test production of the product in 2023, targeting annual production of 200,000 metric tons per year by 2030.
Finding an alternative for resorcinol has been the subject of much research and development in the past decade.
The company will also begin work on developing reinforcing-fiber applications for other rubber products, including belts and hoses.
The company's U.S. operations are based in New York.