In the modern rubber and polymer composites industry, the interfacial compatibility between fillers and the matrix is crucial in determining the performance of the final product. IOTA-Si69 (bis-[3-(triethoxysilyl)propyl]-tetrasulfide) is a silane coupling agent with multiple functions including coupling, crosslinking, reinforcement, and softening, and is hailed as the "invisible engineer in rubber formulations."

Key Characteristics:
- Molecular Formula: C₁₈H₄₂O₆S₄Si₂, CAS No.: 40372-72-3
- Appearance: Pale yellow transparent liquid with a slight ethanol odor
- Solubility: Easily soluble in organic solvents such as ethanol, acetone, benzene, and toluene; insoluble in water
- Content ≥22.5%, Refractive Index 1.49, Density 1.08 g/cm³

Why is it important? IOTA-Si69's unique structure allows one end to react with the hydroxyl groups on the surface of inorganic fillers (such as silica, carbon black, and talc), while the other end participates in the rubber vulcanization network via sulfur bonds. This "bridging" effect significantly improves filler dispersibility and reduces agglomeration, thereby improving the processing performance and mechanical strength of the rubber compound.

In tire manufacturing, it effectively reduces rolling resistance and improves wet skid resistance and wear resistance—one of the key technologies for green tires (low fuel consumption and high safety).