3-Glycidoxypropyltrimethoxysilane
An epoxy-functional silane that forms chemical bridges between coatings and glass, metal or concrete, improving adhesion, especially when wet.
3-Glycidoxypropyltrimethoxysilane is an organofunctional silane with a glycidyl (epoxy) group at one end of a propyl chain and three methoxy groups on silicon at the other (formula C₉H₂₀O₅Si). It is a clear liquid.
GPTMS is used as an adhesion promoter added to epoxy, polyurethane and acrylic coatings, adhesives and sealants, as a primer component for glass and metal, and as a coupling agent for mineral fillers.
The methoxysilyl groups hydrolyze with moisture to form silanols, which condense with hydroxyl groups on glass, metal oxides and concrete to form Si–O–substrate bonds. The epoxy end reacts with amine hardeners or other resin groups, linking the coating chemically to the surface. Hydrolysis releases methanol.
Can irritate eyes and skin, and hydrolysis liberates methanol vapor. Ventilate and protect eyes and skin; keep containers sealed to prevent premature hydrolysis.
Usually a small amount, often well under 2% of the formula, with the exact level found by testing.
Choose the organic group that reacts with your binder: epoxy silanes suit amine-cured epoxies and some urethanes; amino silanes suit epoxies and isocyanate systems.
