The requirements for the mechanical properties of silicone depend mainly on the application. Silicone resins used as electrical insulating varnishes, coatings and adhesives are concerned with hardness, elasticity, thermoplasticity and adhesion. The hardness and elasticity of the silicone paint film can be varied over a wide range by adjusting the molecular structure of the resin. When the content of trifunctional or tetrafunctional link is higher, that is, the higher the crosslink density, a film with high hardness and low elasticity can be obtained; the introduction of a large sterically hindered substituent can improve flexibility and thermoelasticity. It is the reason why the flexibility and thermoplasticity of methylphenyl silicone are superior to those of methyl silicone. Therefore, silicone resin does not need to use a special plasticizer, but the proper combination of soft and hard silicone resin can meet the plasticity requirements.
When used as a certain coating, the hardness of the pure silicone coating film is insufficient, and the thermoplastic is sufficient; if an organically modified silicone resin is used, it is easy to solve this contradiction.
Pigments and catalysts can also affect the hardness and elasticity of silicone resins. Pigments have the effect of accelerating the oxidation of silicone paint films and converting them into harder silica glass. Using a low activity catalyst, since the condensation reaction is incomplete, only a soft coating can be obtained; conversely, a highly active catalyst (such as a compound such as Pb, Al, etc.) can be used to obtain a hard and brittle coating, but some catalysts (such as titanium) The acid ester can effectively increase the hardness of the coating without seriously reducing the elasticity.
Silicone has good adhesion to iron, aluminum, silver, tin, glass and ceramics, but has poor adhesion to copper. Especially after high temperature and long-term heat aging, it may cause the oxide film on the copper surface to have Accelerate the thermal cracking reaction of silicone. The adhesion of silicone grease to organic materials such as plastics, silicone rubber, etc. depends mainly on the surface energy of the latter and compatibility with silicone. The lower the surface energy and the less compatible the material, the harder it is to bond. The adhesion of the silicone resin to the difficult-to-bond substrate can be improved to some extent by the treatment of the surface of the substrate (including sanding and priming), especially by introducing a tackifying component into the silicone resin.
Contact：Sharon Song(Sales manager)
Zhejiang Runhe Organosilicone New Material Co.,Ltd(Factory)
Zhejiang Runhe Chemical New Material Co.,Ltd(Exporter)
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