1. Organosilicon - a new material with increasing permeability


Silicone generally refers to chemical molecular materials with carbonyl groups connected to the four bonds of silicon atom. Silicon atom contains various organic groups, including methyl, ethyl, alkoxy, phenyl, etc. but at present, the most important application is [si-o-si-o] n as the main chain, and the other two groups on silicon atom are methyl cyclosiloxane (DMC), with the downstream proportion of more than 90%. It is also what we call silicone monomer.


The synthesis of silicone requires the synthesis of silicon powder and methyl chloride. About 0.25 tons of silicon powder and 0.8 tons of methyl chloride synthesize 1 ton of crude monomer, including methylchlorosilane, dimethylchlorosilane, trimethylchlorosilane, high boiling matter, low boiling matter, hydrosilane, etc. as a monomer for the synthesis of DMC, dimethylchlorosilane can increase the yield to more than 85% through repeated disproportionation of dimethylchlorosilane. Dimethylsiloxane DMC (D4 is a kind of DMC) is generated by dimethyl hydrolysis, cracking and distillation. It is generally estimated that 0.5T DMC is synthesized from 1t crude monomer.


1.1. Electrical insulation, high and low temperature resistance, heterogeneous high adhesion and water resistance are the four excellent properties of silicone


Silicone special chemical bond brings excellent properties. Silicone is a polymer with [- Si-O -] n group as the framework and the remaining two bonds of silicon atom connecting two methyl groups. Due to the chemical bond energy properties of Si-C bond and Si-O bond, silicone has many excellent properties, such as better electrical insulation and better temperature tolerance, that is, it can withstand the limit temperature of - 50 ° C to 300 ° C without aging. Because the groups on both sides are different in affinity to organic and inorganic media, organic silicon can bond organic and inorganic media very well. At the same time, due to the properties of silicon atoms, silicone has very good water resistance and can be used for various waterproof seals.


Excellent performance has brought a wide range of applications, and the traditional demand is mainly silicone rubber. Silicone is generally made of silicone rubber polymerized by silicone oxygen bond. Due to the excellent performance of silicone, silicone products have been widely used as a high-performance material. They have been successively known as "industrial monosodium glutamate", "industrial vitamin" and "industrial catalyst", which shows that their status is continuously improving. For example, silicone rubber is widely used as the binder of glass curtain wall because of its very good ability to bond "organic-inorganic medium" and its ability not to age at extreme temperature. Due to its good sealing effect, silicone rubber sealing materials are widely used in automotive electronic device packaging, waterproof packaging required in building decoration, etc. Due to its anti electricity effect, the insulating material required by power equipment is also an important use of silicone. In general, the domestic downstream demand for silicone is still dominated by silicone rubber, and the domestic downstream demand accounted for about 66.9% in 2018. In addition to silicone rubber, silicone is also mainly used in downstream demand fields such as textiles, daily chemical silicone oil, silicone resin and silane coupling agent.