A STUDY ON INCREASEING RECYCLED RUBBER CONTENT IN SOLID TYRE TREAD COMPOUNDS BY INCORPORATING BALLOON AND FOAM RUBBER WASTE

The solid tyre and latex industries face significant economic and environmental challenges due to their reliance on virgin rubber and waste materials. This study examines the integration of recycled latex balloon and foam rubber waste into solid tyre tread compounds. The aim is to formulate a compound that optimizes the use of recycled materials while adhering to the quality standards required for solid tyres. The experimental design included a control formulation (Test 1) comprising only natural rubber, and a test formulation (Test 2) incorporating natural rubber mixed with reclaimed balloon waste at a 70:30 ratio. Further tests (Tests 3-6) introduced varying proportions of latex foam waste, starting from 10 phr and increasing in 5 phr increments up to 25 phr, to the Test 2. (Virgin to Recycled ratio T3- 64:36, T4-60:40, T5-58:42, T6-56:44). Results reveal that incorporating recycled latex affects cure characteristics and physical properties. Specifically, increased recycled latex content reduces cure and scorch time while enhancing the cure rate. Torque properties relatively remain stable. The addition of recycled latex foam waste improves rebound resilience but results in decreased tensile strength, modulus, elongation at break, tear strength, and hardness. Notably, the aging performance in terms of hardness and modulus is comparable to virgin rubber, whereas elongation at break, tensile strength, and tear strength show improvements over the virgin compound. In conclusion, a formulation with 70:30 ratio of natural rubber to balloon waste and 20 phr of latex foam waste meets acceptable quality levels though it reduces modulus and tensile strength. This offers a viable, cost-effective alternative for sustainable solid tire tread compounds, addressing high raw material costs and supporting recycling and sustainability goals.