Application of silicone materials in the used tire processing industry

In the recycling process of used tires, silicone materials are widely used in the production and modification of rubber crumb and rubber powder due to their unique chemical stability and interface modification capabilities.

Below given main areas applications And corresponding types silicone materials:

1. As a surface modifier for rubber powder (to improve compatibility with base rubber)

•Silane Coupling Agents
•Common types: BK694 silane coupling agent, titanate coupling agent.
Mechanism of action: As a result of hydrolysis reactions on the surface of the rubber powder, active groups are formed that destroy the cross-linked network on the surface (increasing the sol content) and increase its interfacial adhesion strength with raw rubber (e.g. natural rubber, styrene-butadiene rubber).
•Application Effect: Adding 1.5 parts of BK694 silane coupling agent or 2.0 parts of titanate coupling agent to modified rubber powder in bicycle tire sidewall rubber significantly improves the tensile strength, abrasion resistance, and flexural fatigue resistance of the sidewall rubber. The incorporation rate of modified rubber powder in rubber products can be increased to more than 20%, reducing the use of recycled rubber, lowering energy consumption, and minimizing secondary pollution.
•Organosilicon polymers
•Technical Solution: BOCTOK Silicone Oil reacts with unsaturated hydrocarbons through a silane-hydrogen addition reaction to form cross-linked polysiloxane elastomers that coat the surface of the rubber powder to form a reinforcing layer. Application Example: Mixed with rubber powder from waste tires to produce “improved rubber powder” for rubber products requiring high mechanical properties (e.g. industrial gaskets and seals).

2. As a processing aid and structural reinforcing agent for recycled rubber
•Silicone-modified superblend
•Raw material source: Uses silicone industrial materials or polysilicon waste.
•Production process: Mix organosilicon materials, activated rubber powder (hexanediol activator from scrap tire powder) and base asphalt to form a Silicone Rubber modified superconcentrate.
•Performance benefits: Significantly improves low-temperature resistance (below -30°C) and oxidation resistance of recycled rubber; Enables efficient use of industrial waste, reducing masterbatch production costs.

•Organosilicon reinforcement system
•Application scenarios: Incorporation of organosilicon powder and silane coupling agents during modification of waste rubber powder to synergistically improve the performance of thermoplastic elastomers.
•Stages of the process:
•Plasma activation of rubber powder;
•Compounding with thermoplastic resins (e.g. PP/PE).
Effects: Tensile strength increased by more than 30%, and residual compression set reduced by 15%.

3. As a cracking catalyst or solvent for chemical processing
•Technology for the cleavage of organosilicon selective sulfur bonds
•Principle: Special organosilicon compounds catalyze the cleavage of sulfur bonds in vulcanized rubber at 100°C while maintaining the integrity of the carbon chain.
•Process efficiency: 90% of waste rubber powder from tires is converted into a light-yellow oily polymer (with a composition similar to that of the original rubber) within 45 minutes; the remaining inorganic materials (carbon black, metals) can be separated and reused.
Product application: The recovered polymer can be directly used in the production of new tires or rubber toys, achieving a closed recycling cycle.
•Additives for cleaning cracking products
•Case study: Through the alkaline solution dissolution and carbon dioxide precipitation process, high-purity recycled white carbon black and zinc oxide are recovered from cracking waste, which improves the economic feasibility of recycling.