The applications of silane coupling agents can be broadly categorised into the following three areas:

First, surface treatment
It improves the bonding properties between the glass fibre and the resin and greatly improves the strength, electrical properties, water resistance and weather resistance of glass fibre reinforced composites. It has a significant effect on improving the mechanical properties of the composite, even in the wet state. The use of silane coupling agents in glass fibres is quite common. The silane coupling agent used in this area accounts for about 50% of its total usage, of which vinyl silane, amino silane, methacryloyloxy silane, etc. are more widely used.

Second, filler plastics
The filler can be pre-surfaced or added directly to the resin. It can improve the dispersion and bonding of the filler in the resin, improve the compatibility of the inorganic filler with the resin, improve the process performance and improve the mechanical, electrical and weathering properties of the filler plastic (including rubber).
Thirdly, it is used as a tackifier for sealants, adhesives and coatings.
It can improve their adhesive strength, water resistance, weathering and other properties. Silane coupling agents can often solve the problem of poor long-term bonding of some materials. The principle of a silane coupling agent as a tackifier is that it has two groups. The groups can be combined with the bonded skeleton material; while the other group can be combined with polymeric materials or adhesives, thus forming strong chemical bonds at the bonding interface and greatly improving the bonding strength. There are three general ways of application of silane coupling agents: one is as a surface treatment agent for skeletal materials; the second is added to adhesives, and the third is added directly to polymer materials. From the point of view of giving full play to its efficiency and reducing costs, the first two methods are better.