3-Aminopropyltriethoxysilane (APTES)
- Ceramic (SiO₂)
- CAS 919-30-2
- IUPAC: 3-aminopropyl(triethoxy)silane
3-Aminopropyltriethoxysilane (APTES) (CAS 919-30-2) appears in 1 of the 1,812 car-care products CarCareTruth tracks (as of June 2026). It is readily biodegradable.
Classified at ingredient level: Acute Tox. 4 oral (H302 — harmful if swallowed), Skin Corr. 1B (H314 — causes severe burns and eye damage), Eye Dam. 1 (H318 — causes serious eye damage). At 1–3% in the wheel-coating mixture, APTES co-drives the mixture-level DANGER classification alongside the cyclosilazane matrix. The primary mechanism is base-catalyzed hydrolysis of the ethoxysilane groups on skin contact, producing alkaline conditions that cause the corrosion classification.
3-Aminopropyltriethoxysilane (APTES, CAS 919-30-2) is a bifunctional silane coupling agent widely used in adhesives, sealants, fiber sizing, and ceramic coating formulas. One end carries a triethoxysilane group that anchors to hydroxyl-rich surfaces (metal oxides, glass, silica) by condensation; the other end carries a primary amine (–NH₂) that provides reactivity with epoxy resins, isocyanates, or cyclosilazane matrices.
Application in wheel coatings: At 1–3% in ceramic wheel coatings, APTES acts as an adhesion promoter — it bonds to the wheel substrate at one end and participates in the ceramic network crosslinking at the other end. The result is improved adhesion of the ceramic film to clear-coated, powder-coated, and polished aluminum wheel surfaces.
Hazard profile: APTES is classified as a skin corrosive (H314 — Cat 1B) and serious eye damage (H318) at the ingredient level. The ethoxysilane groups hydrolyze on contact with moisture on skin or eyes, generating silanol groups and ethanol; the amine group makes the product locally alkaline. Collectively this produces the corrosion classification. At 1–3% in the finished wheel coating, APTES contributes to (but does not solely drive) the mixture-level H314 and H318 classification. Nitrile gloves and safety glasses are required.
Environmental: APTES hydrolyzes readily in water to give 3-aminopropylsilanetriol and ethanol, both biodegradable. No PBT or vPvB classification. Not PFAS. Low aquatic toxicity in typical formulated concentrations.
Health & environment profile
- VOC
- no
- Prop 65 listed
- no
- Asthmagen
- no
- EPA Safer Choice
- no
- Aquatic toxicity
- no
- Biodegradable
- yes
- Bioaccumulative
- no
- Persistent
- no
- Ozone depleting
- no
- Microplastic
- no
- PFAS
- no
- Env. score
- 5/5
Common questions about 3-Aminopropyltriethoxysilane (APTES)
- What is 3-Aminopropyltriethoxysilane (APTES) used for in car care?
- Adhesion promoter — amine-functional silane that anchors the ceramic active to metal-oxide and hydroxyl-rich wheel surfaces via condensation with surface silanol groups
- Is 3-Aminopropyltriethoxysilane (APTES) a VOC?
- No. 3-Aminopropyltriethoxysilane (APTES) is not classified as a volatile organic compound (VOC).
- Is 3-Aminopropyltriethoxysilane (APTES) on California's Proposition 65 list?
- No. 3-Aminopropyltriethoxysilane (APTES) is not on California's Proposition 65 list.
- Is 3-Aminopropyltriethoxysilane (APTES) biodegradable?
- Yes. 3-Aminopropyltriethoxysilane (APTES) has a confirmed biodegradable profile.
1 product contain this
Related
Health and environment notes translate the manufacturer Safety Data Sheet, the GHS classification, and authoritative regulatory listings (California Prop 65, EPA). Not medical advice. They describe the ingredient itself; whether a hazard applies to a finished product depends on its concentration and how it's used.