Application of coupling agent in adhesives and sealants

Adding silane coupling agent into the adhesive can not only improve the adhesive strength, but also improve the durability and hygrothermal aging resistance of the adhesive. For example, although polyurethane has high adhesion to many materials, its durability is not ideal. After adding silane coupling agent, its durability can be significantly improved. When some experts study the hygrothermal durability of titanium alloy adhesive parts, the retention rate of shear strength of the adhesive parts after hygrothermal aging is greatly improved by adding silane coupling agent into the epoxy adhesive. Silane coupling agent can even be directly used as adhesive for bonding metal with silicone rubber, fluororubber, nitrile rubber, etc.

In order to improve some properties of organic adhesives (such as heat resistance, self extinguishing, dimensional stability, etc.), or to reduce the cost of organic adhesives, some inorganic fillers are often added to the adhesives. If silane coupling agent is used to treat the filler in advance, because the polar groups on the surface of the filler react with the silane coupling agent, the structural interaction between the filler and the resin is greatly reduced, which not only greatly improves the compatibility and dispersion of the filler to the adhesive matrix resin, but also significantly reduces the viscosity of the system, thus increasing the amount of filler.

Adding silane coupling agent into the adhesive can not only improve the adhesive strength, but also improve the durability and hygrothermal aging resistance of the adhesive.

The results show that the shear strength preservation rate of the bonding parts after wet heat aging is improved from 80% to 97%. Silane coupling agent can even be directly used as adhesive for bonding metal with silicone rubber, fluororubber, nitrile rubber, etc

Improve the heat resistance, self extinguishing and dimensional stability of organic adhesive

To reduce the cost of organic adhesives, we often need to add some inorganic fillers, surface treatment fillers, increase the amount of fillers and reduce the cost

Outstanding advantages of silane coupling agent in adhesive and sealant industry

Cost saving

The addition of inorganic fillers in the pretreated adhesive reduces the structural interaction between fillers and resin, greatly improves the compatibility and dispersion of fillers to the adhesive matrix resin, and obviously reduces the viscosity of the system, thus increasing the amount of fillers.

Enhanced adhesion

Silane coupling agent can set up a "molecular bridge" between the interface of inorganic and organic materials, and connect the two materials with completely different properties, so as to effectively improve the bonding strength of the interface layer.

Polymer modification

Silane coupling agent can improve the polymer, enhance the heat resistance, self extinguishing, dimensional stability and other properties of the organic adhesive, and improve the dura

Application of silane coupling agent

The silane coupling agent is directly added into the adhesive components, and the amount of silane coupling agent is generally less than 1-5% of the amount of matrix resin. After gelatinization, the molecules of coupling agent migrate to the bonding interface to produce coupling effect. For the adhesive that needs to be cured, it needs to be placed for a period of time before curing, so that the coupling agent can complete the migration process, and then a better effect can be obtained.

① In structural adhesives, the bonding between metal and nonmetal, if silane type tackifier is used, can be condensed with metal oxide, or with another silanol, so that the silicon atoms are in close contact with the surface of the adhesive. If silane is added to NBR phenolic structural adhesive as tackifier, the bonding strength can be improved significantly.

② Silane has been widely used as a treatment agent in bonding glass fiber at home and abroad. It can react with the interface to improve the bonding strength. For example, the peel strength of chloroprene adhesive is 1.07kg/cm2 when silane is not used as treatment agent, and 8.7kg/cm2 when aminosilane is used as treatment agent.

③ In the bonding of rubber and other materials, silane tackifier has a special function. It can obviously improve the bonding strength between various rubbers and other materials.

For example, when the glass is bonded with polyurethane rubber, if silane is not used as the treatment agent, the peel strength of the adhesive is 0.224 kg / cm2, if silane is added, the peel strength is 7.26 kg / cm2.

④ In some cases, silane coupling agent can be used to solve the bonding problems that can not be solved by ordinary adhesives. For example, aluminum and polyethylene, silicone rubber and metal, silicone rubber and plexiglass can all be solved satisfactorily by choosing the corresponding silane coupling agent according to the chemical bond theory.

The general adhesive or resin with coupling agent can not only improve the adhesive strength, but also increase the water resistance and durability of the adhesive force. For example, polyurethane and epoxy resin have high adhesion to many materials, but the adhesion durability and water resistance are not ideal. After adding silane coupling agent, the performance can be significantly improved.

bility and hygrothermal aging resistance of the adhesive.