The application of silane coupling agents can be roughly summarized into three aspects:
(1) The surface treatment of glass fibers can improve the bonding properties of glass fibers and resins, and greatly improve the strength, electrical, water resistance and climate resistance of glass fibre reinforced composites. Even in wet state, it can improve the mechanical properties of composites, and the effect is remarkable.
At present, silane coupling agents are widely used in glass fibers, which account for about 50% of the total consumption. Vinyl silane, aminosilane, methacryloxysilane and so on are widely used.

(2) Filling plastics with inorganic fillers. Surface treatment of fillers can be carried out in advance, and the fillers can also be directly added to the resin. It can improve the dispersion and adhesion of fillers in resins, process properties and mechanical, electrical and climatic properties of filled plastics (including rubber).

(3) Used as sealants, adhesives and paint tackifiers, they can improve their bonding strength, water resistance, climate resistance and other properties. Silane coupling agents can often solve the problem that some materials have been unable to bond for a long time.
The principle of silane coupling agent as tackifier is that it has two groups: one group can be bonded with the bonded skeleton material, and the other group can be bonded with the polymer material or the bonding agent, thus forming a strong chemical bond at the bonding interface, which greatly improves the bonding strength. The application of silane coupling agent generally has three methods: one is as surface treatment agent of skeleton material; the other is added to adhesive; the third is directly added to polymer material. From the point of view of giving full play to its efficiency and reducing cost, the first two methods are better.

The specific application of silane coupling agent in adhesives industry includes the following aspects:
(1) In structural adhesives, the bonding between metal and non-metal can be condensed with metal oxides or with another silane alcohols if silane tackifiers are used, so that the silicon atoms are in close contact with the surface of the adhesives. If silane is added to NBR phenolic structural adhesive as tackifier, the bonding strength can be significantly improved.

(2) Silane has been widely used as a treatment agent in bonding glass fibers at home and abroad. It can react chemically with the interface to improve the bonding strength. For example, the bonding peel strength of chloroprene adhesive is 1.07 kg/cm 2 when silane is not used as treatment agent, and 8.7 kg/cm 2 when amino silane is used as treatment agent.

(3) Silane tackifier has special function in bonding rubber with other materials. It obviously improves the bonding strength of various rubber and other materials. For example, when glass is bonded to polyurethane rubber, the peeling strength of the adhesive is 0.224 kg/cm 2 without silane as a treatment agent, and 7.26 kg/cm 2 with silane.

(4) The bonding problems that could not be solved by general adhesives can sometimes be solved by silane coupling agents. For example, aluminium and polyethylene, silicone rubber and metal, silicone rubber and organic glass, the corresponding silane coupling agent can be selected according to the chemical bond theory, and satisfactory solution can be obtained. For example, polyethylene can be bonded to aluminium foil with vinyl triperoxide tert-butyl silane (Y-4310); and silicone rubber can be bonded to metal with butadiene triethoxysilane with a tensile strength of 21.6-22.4 kg/cm 2.

General adhesives or resins combined with coupling agents can not only improve the bonding strength, but also increase the water resistance and durability of the bonding strength. For example, polyurethane and epoxy resin have high adhesion to many materials, but their durability and water resistance are not ideal. After adding silane coupling agent, their properties can be significantly improved.