3-Aminopropyltriethoxysilane (A-1100 / KH-550)

3-Aminopropyltriethoxysilane (APTES, A-1100/KH-550) is a primary amine-functional organosilane coupling agent widely used for glass fiber sizing and mineral filler treatment in epoxy resin systems. The primary amine group (–NH₂) reacts directly with epoxy groups during cure, integrating the silane into the cured matrix and forming a strong, durable chemical bond at the resin-reinforcement interface.

A-1100 is particularly effective in epoxy composite systems due to its direct chemical reactivity with epoxy resins. In glass-fiber-reinforced epoxy, aminosilane-sized glass fibers consistently show the highest dry and wet interlaminar shear strength among all silane types. The amine group also acts as a latent curing agent for epoxy, meaning A-1100 on the glass surface slightly accelerates cure in the fiber-matrix interface zone, which improves adhesion.

For mineral filler treatment (wollastonite, kaolin, silica), A-1100 at 0.5–1.5% on filler weight provides a primary amine surface that acts as a reactive coupling site for epoxy matrix systems. This application is critical in epoxy casting compounds, potting compounds, and structural adhesives where high-temperature, wet, or vibration loading might otherwise delaminate untreated filler particles from the matrix. A-1100 is also used in aqueous systems as a surface primer for glass bonding and as an intermediate primer promoting adhesion between inorganic and organic layers.