- ▸ Coupling agent: Links silica filler to rubber and polymer matrices.
- ▸ Adhesion promoter: Promotes filler-to-polymer adhesion in compounds.
- ▸ Processing aid: Acts as a processing aid and reaction regulator in compounding.
- ▸ Intermediate: Used as a chemical intermediate.
A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.
Request SDS →Bis[3-(triethoxysilyl)propyl] disulfide (CAS 56706-10-6) is a sulfur-functional organosilicon compound. It is used as an adhesion/cohesion promoter, intermediate, processing aid, and chemical reaction regulator. Its triethoxysilyl groups react with silica surfaces while the disulfide bridge links to the polymer.
Regulatory & registration requirements
- TSCA (US):
- REACH (EU):
- EC number: 260-350-7
TSCA Inventory flag PMN: a commenced PMN (premanufacture notice) substance (EPA flag legend).
Source: EPA TSCA Inventory (July 2025 release) · ECHA CHEM — retrieved 2026-07-12
Solutions Using This Product
Process-solution guides on this site that specify this chemistry:
- Rubber & Elastomer Compounding Ingredients (Industrial Manufacturing)
- Sulfur Silanes for Silica Tire-Tread Coupling (Plastics & Polymers)
Frequently Asked Questions
What does "bis" mean in the name of this silane?
In chemical nomenclature "bis" means two of the named group. Here it indicates two 3-(triethoxysilyl)propyl groups joined by a disulfide bridge, giving the structure of CAS 56706-10-6 (C18H42O6S2Si2).
What is bis-[3-(triethoxysilyl)propyl] disulfide (Si-75, TESPD) used for?
It is a sulfur-functional organosilicon coupling agent. The triethoxysilyl groups react with silica surfaces while the disulfide bridge links to the polymer, making it an adhesion/cohesion promoter, processing aid, and reaction regulator that bonds silica filler to rubber and polymer matrices.
How does TESPD (Si-75) differ from the tetrasulfide (Si-69, TESPT)?
Both are triethoxysilylpropyl silica coupling agents; the difference is the sulfur bridge. Si-75 is the disulfide (two sulfur atoms, CAS 56706-10-6) while Si-69 is the tetrasulfide (four sulfur atoms, CAS 40372-72-3). The lower sulfur rank affects scorch behavior and crosslink contribution in rubber compounding.
What is the CAS number and HS code for this coupling agent?
Bis[3-(triethoxysilyl)propyl] disulfide is CAS 56706-10-6, molecular formula C18H42O6S2Si2. It classifies under HS 2931.90 (organo-inorganic compounds, other); we confirm the destination-specific code on the quote.
How is this silane supplied in bulk and can you provide a CoA and SDS?
We supply TESPD/Si-75 in bulk industrial packaging for rubber and polymer compounders, with packaging and MOQ confirmed per order. A Certificate of Analysis and Safety Data Sheet are available with each shipment; request a bulk quote with your target volume.
What is the REACH and TSCA regulatory status of Bis Disulfide (TESPD)?
Bis Disulfide (TESPD) (CAS 56706-10-6) is subject to U.S. TSCA Inventory requirements; supplying it into the EU requires valid REACH registration ((EC) No 1907/2006). RawSource cannot verify a third-party supplier's registrations — buyers should require documented TSCA and REACH compliance for their jurisdiction and volume (EC 260-350-7).