Silicones & Silicates
REACH
Methyltriacetoxysilane
CAS Number
4253-34-3
EC Number
224-221-9
Abbreviation
MTAS
What is Methyltriacetoxysilane?
Methyltriacetoxysilane (CAS 4253-34-3), abbreviated MTAS, is an acetoxy-functional silane used as a crosslinker and curing agent in adhesive, sealant and coating systems.
Where is Methyltriacetoxysilane used?
- Adhesives and sealants: primary crosslinker in one-component acetoxy-cure silicone sealants
- Construction, glazing and sanitary grades: fast surface cure and strong substrate adhesion
- Industrial coatings: surface modifier improving adhesion to glass, metals and mineral substrates
- Silicone elastomer compounding: controls network density and mechanical properties in RTV systems
- In personal care it crosslinks silicone at ambient conditions in film-forming and conditioning systems.
Good to know: Releases acetic acid upon moisture exposure, triggering condensation cure in silicone-based formulations.
Commercial specifications
- Purity commonly 97% or higher
- Drum and IBC quantities; small containers for laboratory use up to bulk quantities
Other Names (Synonyms)
Triacetoxy(methyl)silane|Methylsilanetriyl triacetate|Silanetriol, methyl-, triacetate|Silanetriol, 1-methyl-, 1,1,1-triacetate|Methylsilanetriol triacetate|Methyltrihydroxysilane triacetate|MTAS
What are the physical properties of Methyltriacetoxysilane?
Melting Point 40.5 °C
Boiling Point 87-88 °C @ Press: 3 Torr
Density 1.175 g/cm³
Flash Point 185 °F
Appearance Colorless or yellowish transparent liquid
Color White or Colorless to Almost white or Almost colorless
Odor Acrid odor
Form solid
Water Solubility 1000g/L at 20℃
Vapor Pressure 0.053-26Pa at 20-25℃
Refractive Index 1.52-1.522
Log P -2.4 at 20℃
How is Methyltriacetoxysilane classified and handled safely? Learn More
Danger
GHS05· Corrosive GHS07· Irritant GHS08· Health Hazard
Hazard Statements
H302 Harmful if swallowed
H314 Causes severe skin burns and eye damage
H315 Causes skin irritation
H318 Causes serious eye damage
Precautionary Statements
P260 Do not breathe dust/fume/gas/mist/vapours/spray.
P261 Avoid breathing dust/fume/gas/mist/vapours/spray.
P264 Wash … thoroughly after handling.
P270 Do not eat, drink or smoke when using this product.
Which trade and regulatory codes apply to Methyltriacetoxysilane?
HS Code 29319090
UN Number 1759
WGK (Germany) 2