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Aminoalkyl-methoxysilyl-terminated dimethyl siloxane

  • Silicones
  • CAS 188627-10-3
  • IUPAC: Dimethyl siloxane, (ethanediamino-2-methylpropyl)methoxymethylsilyl)oxy- and C13-15-alkoxy-terminated

GHS classified Skin Irrit. 2 (H315) and Eye Irrit. 2 (H319) at the ingredient level per the published WetCoat SDS. The reactive methoxysilyl end groups release small amounts of methanol on hydrolysis, but at typical 5–7% concentrations in a finished spray-and-rinse product the mixture-level classification carries forward H319 only. Not a respiratory sensitizer (no H334), not a skin sensitizer (no H317).

This is the proprietary silane-functional polydimethylsiloxane that Gyeon uses as the bonding active in WetCoat (and likely related Q²M SiO₂ toppers). The molecule is a silicone-oil backbone capped with aminoalkyl-methoxysilyl groups at one end and C13–C15 alkoxy groups at the other. When sprayed onto a wet, clean surface, the methoxysilyl ends hydrolyze and condense with surface hydroxyls (paint clear coat, glass, ceramic-coated panels) to form a thin, hydrophobic siloxane film — the layer that produces the tight beading and "wet look" gloss buyers see immediately. At the 5–7% concentration disclosed in the Gyeon WetCoat SDS, the ingredient drives the product-level eye-irritation classification (H319). The aminoalkyl group is mildly basic but the product is buffered to pH 7, so skin/eye irritation in normal spray-and-rinse use is limited to the brief contact window before rinse-off. No respiratory sensitizer classification, no aquatic toxicity classification, no Prop 65 listing.

Health & environment profile

VOC
no
Prop 65 listed
no
Asthmagen
no
EPA Safer Choice
no
Aquatic toxicity
no
Biodegradable
no
Bioaccumulative
no
Persistent
yes
Ozone depleting
no
Microplastic
no
PFAS
no
Env. score
4/5
Purpose: Functionalized polydimethylsiloxane with aminoalkyl-methoxysilyl end groups; the bonding active in SiO₂ wet-on-wet spray toppers and several aminoalkyl-silane coating chemistries

1 product contain this

Health summaries are editorial — we synthesize from SDSs, peer-reviewed sources, and regulatory listings. Not medical advice.