The development process is mainly divided into three stages
The first stage (1900--1940)
Basic organosilicon compound synthesis, including silicone monomers for the synthesis of high polymers, and silicones
Theoretical formation stage
The second stage (1941--1965)
Synthesis and industrial production stage of silicone polymer compounds
The third stage (1965 - now)
Promote application and comprehensive development stage
The latest research direction: the development of silicone chemistry and industry in the past two decades has come to a new stage of research in new areas mainly
1. Silicone materials related to life sciences
2. Research on organosilicon compounds that can be used as drugs and pesticides
3. Preparation of high-strength SiCSiN4 ceramic fiber by polysiloxane and polysilazane
4. Polysiloxane-containing conductive material  nonlinear optical material  liquid crystal material.
The second part of silicone adhesive
Silicone-based adhesive is based on silicone or modified silicone resin. It is formulated with a curing agent and inorganic filler. A type of adhesive composed of materials and organic solvents. Solvents and condensation reactions should be excluded when curing such adhesives.
Raw small molecular volatiles are generally heated and cured. The outstanding feature is the high temperature resistant pure silicone tree
After curing, the grease can work at 300 ° C for a long time without breaking the short-term working temperature, which can reach 800 ° C or even
1000 ° C. Mainly used for bonding non-structural parts and screws such as heat-resistant materials for metal and fiber fabrics, FRP, etc.
Sealed and fixed.
Basic composition of silicone resin adhesives
1, filler
Fillers are an important part of silicone resin adhesives. The heat resistance of the adhesive is very good or bad
The degree depends on whether the filler selected is correct. There are three main types
1. Mineral filler
a, asbestos powder, its fibrous structure can prevent the rubber layer from shrinking due to cold and heat action
b. Mica powder is used to improve the wettability of the adhesive layer and the surface of the adherend
c, talc powder incremental filler
2. Metal and metal oxide powder
Metal powder mainly has aluminum powder, zinc powder
Metal oxide powder
a, SiO2 improves process performance
b, TiO2 improves strength and improves oxidation resistance
c, ZnO can neutralize trace amounts of acid hydrazine to prevent corrosion on metal surfaces
In addition, different powders are added according to different temperature zones
F2O3200°C～300°CCr2O3400°C～500°CMnO2600°C～900°C
3, glass powder, quartz powder
Glass powders with different melting temperatures can form inorganic eutectic films at high temperatures. This film has extremely high heat resistance
Sex.
2, solvent
Silicone has a three-dimensional structure. The normal state is a viscous liquid or solid. As a component of the adhesive, it is generally
Solvents are dissolved in a specific solvent. The commonly used solvents are toluene, xylene, ethyl acetate, butyl acetate, and butyl ring. Ketones, etc.
3, curing agent
The curing agent used in the pure resin type adhesive mainly has
Naphthenate Pb, Zn, Mn, Fe, Co, Sn<100°C
Octanoate Zn,Sn
Metal amine complex [Ni(en)2(H2O)2]Ac; [Cu(en)2]Ac250°C～100°C
Silicon nitride or silicon nitride resin
A-39 silicon nitrogen curing agent 前MCH-7 polymethylsilazane in the former Soviet Union
Lanzhou Chemical Industry Co., Ltd. Coatings N-5 Curing Agent
Beijing Institute of Chemistry KH-Cl.
In addition, there are dibutyltin tin silicate, tetraethyl orthosilicate, aluminum triacetylacetonate, benzyl dimethylamine, etc.
4, adhesive resin:
Silicone resin is the main material of silicone adhesives, and its properties directly determine the properties of such adhesives
can.
Pure silicone resin can be divided into condensation type silicone resin and silicone resin according to the curing method.
Peroxide-initiated silicone.