Film Former
METHYLTRIMETHOXYSILANE
Safety score · 0–100
Moderate
Derived from EU CosIng regulatory status, PubChem hazard data and published research. How we score.
About
A reactive silane monomer (CAS 1185-55-3) that crosslinks to form silicone films. Releases methanol during cure — used as a processing intermediate, not typically leave-on at high levels.
Methyltrimethoxysilane (MTMS, CAS 1185-55-3) is a trifunctional silane monomer used to crosslink silicone resins and to treat pigments and fillers. On contact with water it hydrolyzes, releasing methanol and forming silanol networks that condense into siloxane films. GHS classifications typically include Flammable Liquid Category 2 and mild eye/skin irritation; it is not classified as a carcinogen, mutagen or reproductive toxicant. In cosmetics the monomer itself is not expected to persist — residual methanol and unreacted silane in the finished product are the main concerns, controlled by good manufacturing.
Function
Skin benefits
- Crosslinks to form water-resistant silicone films
- Improves wear in long-lasting products
- Useful surface modifier
Known concerns
- Releases methanol on hydrolysis
- Flammable monomer — GHS Flam. Liq. 2
- Eye/skin irritant in raw form
References
EU CosIng database
European Commission cosmetic ingredient registry — regulatory status, restrictions, authorised functions.
Related film formers
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This profile is for educational purposes and does not constitute medical advice. Regulatory status and scientific understanding evolve — always read the physical product label and consult a healthcare professional for personal concerns.