"Discover Methyltris(methylethylketoxime)silane (CAS 22984-54-9), the most widely used oxime-type crosslinker for neutral-cure RTV silicone sealants. Learn its properties, mechanism, and applications."
-Deshangchemical-chemechemi
Methyltris(methylethylketoxime)silane, commonly abbreviated as MOS or referred to as an oxime-type Methyltris silane, is the cornerstone crosslinker in neutral-cure room-temperature vulcanizing (RTV) silicone systems. With CAS number 22984-54-9 and molecular formula C₁₃H₂₇N₃O₃Si, this compound has revolutionized the sealant and adhesive industry by enabling odor-free, non-corrosive curing of silicone rubbers.
Physical and Chemical Properties
Molecular Weight: 301.46 g/mol
Appearance: Colorless to pale yellow liquid
Boiling Point: ~245°C
Density: ~0.985 g/mL at 25°C
Purity: ≥95% (commercial grade), ≥98% (high purity)
EC Number: 245-366-4
Curing Mechanism
The distinctive advantage of Methyltris(methylethylketoxime)silane over acetoxy or alkoxy crosslinkers lies in its neutral curing mechanism. During moisture cure, the oxime groups (–ON=C) are released as methyl ethyl ketoxime (MEKO) instead of acetic acid or alcohol. This results in:
No acid corrosion of metallic substrates
Minimal odor during curing
Excellent adhesion to metals, glass, and plastics
Faster surface cure rate compared to alkoxy systems
Applications in Silicone Sealant Formulations
Construction Sealants
The dominant use of CAS 22984-54-9 is in one-component (1K) neutral-cure silicone sealants for construction. These include facade glazing sealants, curtain wall systems, window and door perimeter seals, and expansion joint fillers. The neutral curing chemistry is compatible with all common construction substrates.
Electronic Potting and Encapsulation
Electronics manufacturers rely on Methyltris-type oxime crosslinkers for potting compounds, conformal coatings, and encapsulants that protect sensitive components from humidity, vibration, and thermal cycling.
Automotive Weatherseals
The rubber-to-metal bonding applications in automotive assembly benefit significantly from the non-corrosive curing nature of this Methyltris silane compound.
Formulation Guidelines
Typical loading levels in neutral-cure RTV systems range from 3–8 parts per hundred resin (phr) relative to the silanol-terminated polydimethylsiloxane base polymer. Catalysts such as dibutyltin dilaurate (DBTL) or organotin compounds are commonly used to accelerate cure.
Important: All operations involving CAS 22984-54-9 must be performed under moisture-free conditions prior to final packaging to prevent premature cure.
Safety and Regulatory Compliance
Methyltris(methylethylketoxime)silane releases MEKO during hydrolysis. MEKO (methyl ethyl ketoxime) is classified as a potential carcinogen by some regulatory bodies and its concentration in finished products must comply with local REACH and OSHA regulations. Always consult the current SDS before formulation.
Sourcing Methyltris(methylethylketoxime)silane
Deshang Chemical provides Methyltris(methylethylketoxime)silane CAS 22984-54-9 in standard packaging (25 kg drums, 180 kg drums) with COA and MSDS documentation. Our supply meets the stringent purity requirements of global sealant manufacturers.
