Characteristics and properties of silicon resin
Source: | Author:ZINCA | Published time: 28 days ago | 10 Views | Share:

    Classification of silicone resin silicone resin is silicon - oxygen - silicon as the main chain, silicon atoms connected with organic base crosslinked type of semi-inorganic polymers.It is with the direct production of organic silicon monomer silicone resin has outstanding weather resistance, is any kind of organic resin is far behind, even under strong ultraviolet radiation, silicone resin is resistant to yellowing.Silicone adhesive silicone adhesive according to the source of raw materials can be divided into silicone resin based adhesive and silicone rubber based adhesive, the former is mainly used for bonding metal and heat resistant silicone on iron, aluminum and tin metal bonding performance is good, glass and ceramics are also easy to bond, but the adhesion of copper is poor.Silicone adhesive based on pure silicone resin.


    Silicone coatings have many disadvantages: poor film forming performance, including high curing temperature, long time, inconvenient construction of large areas, and poor adhesion of the film to the bottom layer.Fluorination modification mainly increases the solvent resistance, oil repellency (viscosity resistance) and reduces the surface energy of silicone resins.The critical surface tension of silicone resins is lower than that of other resins, but higher than that of fluorine resins.


    Silicon resin is a thermosetting plastic, one of its most outstanding properties is excellent thermal oxidation stability.After heating at 250℃ for 24 hours, the weight loss of silicone resin is only 2-8%.Another outstanding feature of silicone is its excellent electrical insulation, which is maintained over a wide range of temperatures and frequencies.


    The number of silicone resin containing organic groups, namely R/Si value, is one of the main indicators to control the quality of silicone resin, silicone curing properties, film flexibility, hardness, heat resistance and heat cracking properties are related to R/Si.The R/Si of general linear silicone oil is slightly greater than 2, the R/Si of silicone rubber is close to 2, and the R/Si of silicone resin is about 1.0.The smaller the R/Si value is, the better curing performance of silicone resin, the smaller the thermal weight loss, the film is hard, but the flexibility is reduced, the film becomes brittle, impact strength is reduced;The higher R/Si value is, the silicone needs to be baked for a long time at high temperature (200-250℃) or cured with the help of drying agent, so that the flexibility is better, the hardness of the film is poor, and the silicone has better impact strength.


    In addition, the performance of silicone resin is also closely related to the type of organic group R, when the organic group is -CH3, can give silicone thermal stability, hydrophobicity, demoulding, arc resistance;When the organic group is -C6H5, the oxidation stability of silicone resin can be improved, and the thermal stability of silicone resin can be improved.When the organic group is -CH=CH2, the curing property and coupling property of silicone resin can be improved.When the organic groups are phenyl and ethyl, the blending ability of silicone resin and organic matter can be improved.When the organic group is -NH2(CH2), the water-solubility of the polymer can be improved, and the coupling ability can be given.The hydrophobicity of silicone resin can be improved when the organic group is long chain alkyl.Therefore, siloxane monomer with different groups can be selected to prepare silicone resin according to specific performance requirements.