The mechanical properties of silicone depend on its application. Silicon resin used as electrical insulating paint, coating and adhesive, people are more concerned about its hardness, elasticity, thermoplasticity and adhesion. The hardness and elasticity of silicone paint film can vary over a wide range by adjusting the molecular structure of the resin. High hardness and low elasticity can be obtained when the content of three or four functional links is higher, that is, the crosslinking density is higher. The introduction of substituents with large steric resistance can improve flexibility and thermoelasticity, which is why the flexibility and thermoplasticity of methyl phenyl silicone resin is better than that of methyl silicone resin. Therefore, silicone resins do not need to use special plasticizers, but rely on the appropriate combination of soft and hard silicone resins can meet the requirements of plasticity.

When used as some coatings, the hardness of pure silicone film is insufficient, but more than thermoplastic; This contradiction can be easily solved by using organic modified silicone resin.
Pigments and catalysts can also affect the hardness and elasticity of silicone. Pigments accelerate the oxidation of the silicone film and convert it to a harder silicon glass. Due to incomplete condensation reaction, only soft coating can be obtained by using low activity catalyst. On the contrary, the use of high activity catalyst (such as Pb, Al and other compounds), can obtain a hard and brittle coating, but some catalysts (such as titanate) can not seriously reduce the elasticity of the premise, effectively improve the hardness of the coating.
Silicon resin has good adhesion to iron, aluminum, silver, tin, glass and ceramics, but poor adhesion to copper, especially at high temperature and long time after thermal aging, it may accelerate the thermal cracking reaction of silicon resin. The adhesion of silicone grease to organic materials such as plastic and silicone rubber mainly depends on the latter's surface energy and compatibility with silicone resin. The lower the surface energy and the worse the compatibility of the material is more difficult to bond. The adhesion of silicone resin to refractory substrate can be improved to a certain extent by treating the substrate surface (including grinding and underpainting), especially by introducing viscosity enhancing ingredients into silicone resin.