Isobutyltrimethoxysilane

Isobutyltrimethoxysilane (CAS 18395-30-7) is an organosilane coupling agent supplied under trade names including Dynasylan IBTMO, Silquest I 7810, Prosil 178, and SS 1120. It carries EC number 242-272-5 and the molecular formula C7H18O3Si. No E-code designation applies to this substance.

In building and construction, it is applied to mineral substrates such as concrete and masonry, where the methoxy groups hydrolyse and bond covalently to surface hydroxyl groups, imparting water repellency. In coatings and sealant formulations, the isobutyl chain provides hydrophobic character while the silane functionality enables cross-linking with inorganic fillers or polymer matrices, improving adhesion and durability.

Isobutyltrimethoxysilane is available as a neat liquid and in solvent-based grades suited to surface treatment applications. The substance is registered under REACH. Packaging typically follows standard industrial formats for reactive silanes, and procurement teams should confirm current SDS documentation and lot-specific purity specifications with the supplier.