In construction, automotive, and electronics assembly, adhesives not only need strong initial adhesion but also must maintain their performance over long periods in harsh environments such as humidity, heat, and salt spray. 3-Chloropropyltrimethoxysilane (CPTMS) is a functional additive that can significantly improve the durability of adhesives.

When added to epoxy, polyurethane, or acrylate adhesives, CPTMS can form a dense silica network at the adhesive/substrate interface through hydrolytic condensation, effectively blocking moisture penetration. More importantly, although its chloropropyl groups do not directly participate in curing like epoxy or amino groups, they can slowly release active sites under alkaline or heated conditions, or introduce polar groups through subsequent reactions, enhancing the chemical adsorption to inorganic substrates such as metals, glass, and ceramics.

Experiments show that after 1000 hours of humid heat aging (85°C/85%RH), the joint strength retention rate of adhesives containing CPTMS is more than 30% higher than that of the blank sample. This is of great significance in scenarios with extremely high long-term reliability requirements, such as automotive windshield bonding, photovoltaic module encapsulation, and marine structural adhesives.

Therefore, although CPTMS is usually used in adhesives at a concentration of less than 1%, it can bring about a significant performance improvement with minimal effort.