Silanes for Rubber & Tire Compounding
Polysulfide and mercapto coupling agents for silica-reinforced tire compounds, rubber-to-metal bonding, and corrosion-resistant primer systems.
Request Samples & TDSSilica-reinforced tire technology — the “green tire” — reduces rolling resistance and improves wet grip compared to traditional carbon black reinforcement. The chemistry that makes this possible is a polysulfide silane coupling agent that bonds the precipitated silica filler to the sulfur-vulcanized rubber network. Without coupling, silica is a poor reinforcement: it clumps during mixing, gives high Mooney viscosity, and detaches from the rubber under load. With coupling, the same silica delivers performance that justifies the additional material cost and processing complexity.
The coupling mechanism works in two steps. During compound mixing, the triethoxysilyl end of the silane hydrolyzes and condenses onto the silica surface, covering the filler particles with organic functionality. During vulcanization, the sulfur bridge in the silane backbone donates sulfur atoms that crosslink into the rubber network, creating covalent bonds from filler surface through to elastomer chain. The length of the sulfur bridge — tetrasulfide (S₄) in TESPT or disulfide (S₂) in TESPD — determines how much sulfur is donated and at what temperature, giving compound engineers a lever to balance coupling efficiency against scorch safety.
Mercaptosilane serves related but distinct applications. The thiol group (-SH) chemisorbs directly onto metal surfaces — copper, gold, silver, steel — through metal-sulfur bond formation, making it the standard coupling chemistry for rubber-to-metal bonding (engine mounts, vibration isolators, conveyor belt splicing) and corrosion-resistant primer systems.
TESPT(Bis(3-triethoxysilylpropyl)tetrasulfide)New
CAS 40372-72-3Si-69 equivalent
The standard polysulfide coupling agent for silica-reinforced tire compounds worldwide. The tetrasulfide bridge (-S₄-) provides the highest sulfur donation per molecule in the polysulfide silane family, delivering strong coupling between precipitated silica and the rubber network during vulcanization. TESPT is consumed at 6–12 wt% on silica loading — typically 1–3 phr in a finished compound. A mid-sized tire plant processing 50,000 tons per year of silica-filled compound consumes 500–1,500 tons per year of polysulfide silane. The trade-off with tetrasulfide chemistry is scorch sensitivity: the four-atom sulfur bridge can release sulfur during high-temperature mixing stages, causing premature crosslinking that stiffens the compound before it reaches the curing press. Compound engineers manage this through controlled mixing temperatures (typically below 145–150°C in the silane reaction step), dump temperature limits, and multi-stage mixing sequences.
Silica-reinforced tire compounds (passenger, truck, high-performance), mechanical rubber goods with silica reinforcement, shoe sole compounds, silicone rubber reinforcement. Key industries: tire manufacturing, technical rubber goods, footwear.
Packaging: 200 kg steel drums, 1,000 kg IBC totes. Store below 40°C, protect from moisture.
Request Specifications →TESPD(Bis(3-triethoxysilylpropyl)disulfide)New
CAS 56706-10-6Si-75 equivalent
Disulfide variant providing tighter process control than TESPT. The shorter disulfide bridge (-S₂-) releases sulfur at higher temperatures and in a narrower window, which translates to three practical advantages on the mixing floor: reduced scorch risk during high-shear compounding, better compound viscosity control (less premature crosslinking means more consistent Mooney values batch to batch), and lower VOC generation during mixing. The trade-off is that TESPD provides less total sulfur donation per molecule, so coupling efficiency is slightly lower than TESPT at equivalent loading. TESPD is increasingly specified by European and Japanese tire manufacturers pursuing tighter process windows and reduced factory emissions.
Silica-reinforced tire compounds where scorch safety is critical, low-emission compounding operations, high-performance tire formulations requiring tight crosslink structure control, compounds mixed at elevated temperatures. Key industries: tire manufacturing (particularly European and Japanese OEM-specified compounds), technical rubber goods.
Packaging: 200 kg steel drums, 1,000 kg IBC totes. Store below 40°C, protect from moisture.
Request Specifications →MPTMS-SH(γ-Mercaptopropyltrimethoxysilane)
CAS 4420-74-0China: KH-590
Mercaptosilane for metal surface bonding and anti-corrosion coupling. The thiol group (-SH) provides strong chemisorption on copper, gold, silver, and steel surfaces through direct metal-sulfur bond formation — a bonding mechanism distinct from both the oxide surface condensation of standard alkoxysilanes and the vulcanization participation of polysulfide silanes. In rubber-to-metal bonding, MPTMS-SH serves as a primer between the metal substrate and the rubber adhesive system, creating a chemical anchor that survives the thermal and mechanical stresses of vulcanization and long-term service.
Rubber-to-metal bonding (engine mounts, vibration isolators, conveyor belt splicing), anti-corrosion primers and coatings, polysulfide sealant adhesion promotion, electronic component surface coupling (gold, copper), self-assembled monolayer formation on metal substrates. Key industries: automotive rubber components, corrosion protection, electronics assembly.
Packaging: 200 kg steel drums, 1,000 kg IBC totes.
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