The silane coupling agent is a kind of organosilicon compound having a special structure, and the formula is YR-SiX3, wherein Y is a functional group capable of reacting with an organic compound, such as an amino group, a vinyl group, a thiol group, an epoxy group, or a methyl group. An acryloyl group or the like; R is a short-chain alkylene group; X is a group which can be hydrolyzed and can form -OH, such as an alkoxy group, an acyloxy group, a halogen, and the like. X and Y are two kinds of reactive groups with different reaction characteristics, in which X easily forms a strong chemical-physical bond with inorganic compounds; and Y is easy to form a strong chemical or physical bond with organic resins, rubbers, etc., and thus is coupled by silane. The agent combines inorganic and organic materials to achieve satisfactory results.

Silicone coupling agent can be used not only as an interface treatment agent, water repellent and reinforcing agent for composite materials, but also widely used as tackifier, surface modifier, crosslinking agent, metal rust and oxidation prevention, glass and ceramics. Protection, fiber and leather finishing, and oil extraction and transportation.

Most of the silane coupling agents are γ-type trifunctional coupling agents, that is, the silicon atom has three hydrolyzable groups attached thereto, and the gamma carbon of the silicon atom is connected with a reactive group, which mainly has the following types: ordinary straight Alkylation coupling agent, not resistant to high temperature: high temperature resistant coupling agent, mainly aromatic silane, such as silane containing cyanophenyl, chlorophenyl, bromophenyl or tolyl; cationic coupling agent, such as XZ -8-5069, wide applicability, soluble in water and organic solvents, not sensitive to air and humidity, active on many thermosetting resins and thermoplastic resins, inorganic materials or metals, enhancing the surface of inorganic and polymer Bonding; water-soluble silane coupling agent, such as the polymer-silanated polyazide proposed by Marsden et al., used in a slurry form to mix with the resin, the effect is good; azide type silane coupling agent, such as S-3046 has the structural formula of (CH3O)3Si-R-SO2N3, which decomposes into active RSO2N upon heating; can be inserted into C-H bond, C=O bond or aromatic system, which can significantly improve the flexural strength of polypropylene (77% increase) And tensile strength (up 65%).
 
In addition to the double bond of the reactive group in the vinyl silane coupling agent on the alpha carbon of the silicon atom, an α-type coupling agent has been developed, which is of the formula Y-CH2Si(OR)3, R=-CH3,- C2H5 and so on. Among such coupling agents, siloxanes are relatively active, chemical reactions are more likely to occur, and high temperature resistance is better than γ-type, and can be used as a crosslinking agent for RTV, but chain scission occurs in a strongly alkaline medium.

In addition, silanated polybutadiene such as Y-9246 is an odorless silane coupling agent which can be used to modify commonly used inorganic fillers]. Peroxide silane coupling agents are a new class of silane coupling agents. The coupling effect is generated by thermal cracking, not hydrolysis, and is suitable for coupling between a large class of similar or dissimilar materials, such as vinyl. Tris(tert-butylperoxy)silane Y-5712, VTPS is an initiator and a tackifier.

The cationic coupling agent and the peroxide type coupling agent are particularly effective for improving the strength of the polyolefin-based thermoplastic resin. The thiol-containing coupling agent has a good effect in the rubber elastomer. The biggest problem with trifunctional silane coupling agents is that the functional groups in the silane easily react with the groups of the resin to reduce the storage stability of the resin, so a series of difunctional silane coupling agents have emerged, overcoming the trifunctional silane coupling. The above disadvantages of the agent.