KBM-802
ShinEtsu;
2931900090
Siwin-S121
31001-77-1
| Quantity: | |
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γ-Mercaptopropylmethyldimethoxysilane (Siwin-S121) is a mercapto-functional silane produced by Siwin, a manufacturer specializing in silane cross-linking agents and silicone additives. With CAS number 31001-77-1, this product serves primarily as a cross-linker for one-pack RTV (room temperature vulcanizing) silicone rubber systems. It also functions as a raw material for silicone oil production and as a surface treatment agent for inorganic fillers.
The molecule contains both mercapto (-SH) and methoxy (-OCH3) functional groups, enabling dual reactivity with organic polymer systems and inorganic substrates. This dual functionality supports commercial procurement applications across silicone rubber manufacturing, silicone polymer synthesis, and composite material production.
Parameter | Value |
|---|---|
Product Code | Siwin-S121 |
Chemical Name | γ-Mercaptopropylmethyldimethoxysilane |
CAS No. | 31001-77-1 |
Appearance | Colorless clear liquid |
Purity | ≥98.0% |
Molecular Formula | C6H16O2SSi |
Molecular Weight | 180.34 g/mol |
Density | 1.00 g/cm³ |
Boiling Point | 96°C |
Flash Point | 93°C |
Refractive Index | 1.45 |
Equivalent Grade | ShinEtsu KBM-802 |
γ-Mercaptopropylmethyldimethoxysilane contains two methoxy groups bonded to silicon, which hydrolyze in the presence of moisture to form silanol groups. These silanol groups undergo condensation reactions with hydroxyl-terminated polydimethylsiloxane polymers, forming Si-O-Si cross-links that build the three-dimensional network structure of cured RTV silicone rubber.
The mercapto functional group (-SH) provides additional reactivity pathways, including thiol-ene click chemistry and metal surface adhesion. The mercapto group also contributes to the characteristic odor of the product, which should be considered during handling and formulation design.
The primary application of γ-mercaptopropylmethyldimethoxysilane is as a cross-linking agent in one-component RTV silicone rubber formulations. It reacts with hydroxyl-terminated silicone polymers in the presence of moisture to form a cured elastomer. Typical loading levels range from 3% to 8% by weight of the silicone polymer base. The mercapto functionality provides enhanced adhesion to metal substrates compared to standard alkoxy silane crosslinkers.
In silicone oil production, the product serves as an intermediate for synthesizing mercapto-functional silicone fluids. These modified silicone oils find use in personal care formulations, textile softeners, and industrial release agents where mercapto groups provide specific functional properties.
The silane treats inorganic filler surfaces including silica, calcium carbonate, and metal oxides. The methoxy groups bond to the filler surface while the mercapto group provides compatibility with sulfur-cured rubber systems. This surface modification improves filler dispersion and enhances mechanical properties in rubber compounds.
In rubber formulations, particularly those based on natural rubber and synthetic elastomers, the mercapto silane acts as an adhesion promoter between rubber matrices and reinforcing fillers or metal reinforcements. It participates in sulfur vulcanization chemistry through the mercapto group, forming covalent bonds between the rubber polymer and the silane-treated surface.
Siwin maintains ISO 9001 quality management system certification for its silane production operations. Each batch of γ-mercaptopropylmethyldimethoxysilane undergoes gas chromatography purity analysis and mercapto content titration to confirm specification compliance. A Certificate of Analysis accompanies each shipment, reporting batch-specific test results. The product meets REACH registration requirements for industrial chemical supply in the European market. Technical support is available to assist enterprise customers with formulation optimization and application troubleshooting.
γ-Mercaptopropylmethyldimethoxysilane is supplied in 200L PVF-lined steel drums. Alternative packaging options are available upon request for commercial procurement orders. The product should be stored in a cool, dry location away from direct light exposure. Light protection prevents photodegradation of the mercapto functional group. Under proper storage conditions in sealed original containers, the product maintains specification compliance for 12 months from the date of manufacture.
Safety handling requires protective gloves, safety glasses, and adequate ventilation. The mercapto group produces a distinct odor that may cause irritation at high concentrations. Standard chemical hygiene practices apply, including spill containment procedures and first aid measures for skin and eye contact.
Typical loading ranges from 3% to 8% by weight of the base polymer. The exact dosage depends on the desired cross-link density, polymer molecular weight, and specific performance requirements of the final sealant or adhesive product.
As a cross-linker, the product directly influences cure rate. Higher concentrations generally accelerate skin-over time and through-cure speed, though the actual cure rate also depends on catalyst type, humidity level, and ambient temperature.
When stored in unopened original packaging at temperatures between 2°C and 30°C, protected from light and moisture, the shelf life is 12 months from the date of manufacture. Opened containers should be purged with dry nitrogen and resealed to prevent moisture-induced viscosity increase.
Yes, γ-mercaptopropylmethyldimethoxysilane is specifically designed for condensation-cure RTV silicone systems. It is compatible with both tin-catalyzed and other condensation cure systems, and the mercapto functionality provides additional adhesion promotion benefits compared to non-functional alkoxy silane crosslinkers.
