The difference between silicone and silicone rubber
  The application of silicone rubber has been extensive, but the understanding and distinction between silicone rubber and silica gel may be unknown, and the name is not fixed. Today, Xiaobian details the difference and classification of silicone and silicone rubber. At present, the concept of the term "silicone" is not standardized, because there is no such thing as the state clearly stated. When we hear the word "silicone", we must understand whether silica or silicon-containing synthetic rubber, or whether it is inorganic silica gel or organic silica gel.


     There are several related words for "silicone": silicone rubber, silicone rubber, and lycopene. The relationship between silicone rubber and silica gel, which is different from silicone and contains silicone rubber. Silicone rubber is the organic "silicone" in "silicone". "Coffee" is the saying of Hong Kong and Taiwan. It is called "silica gel" in mainland China. Silicone and Silicone are the transliteration of English silicone. We usually say that it means "silicone."


  In summary, silica gel can be divided into organic silica gel and inorganic silica gel according to its nature and composition.

Let me talk about silicone rubber


First, the technical parameters of silicone rubber


    Silicone rubber is one of the largest and most widely used products in silicone products. Silicone rubber has excellent resistance to high, low temperature, weather resistance, water repellency, electrical insulation and physiological inertness.


    Main properties and applications of silicone rubber products: According to their vulcanization temperature, silicone rubber can be divided into high temperature (heating) vulcanization type and room temperature vulcanization type. High temperature glue is mainly used to manufacture various silicone rubber products, while room temperature glue is used. Mainly used as a bonding agent, potting material or mold.


    Thermal vulcanized silicone rubber (HTV)


    Hot vulcanized silicone rubber (HTV) is the most important type of silicone products. Methyl vinyl silicone rubber (VMQ) is the most important type in HTV, commonly known as high temperature glue. Methyl vinyl silicone rubber (green rubber) is a colorless, odorless, non-toxic, non-mechanical impurities. The raw rubber is mixed with additives such as a suitable reinforcing agent, structure control agent and vulcanizing agent as needed. Refining, then heating molding or extrusion molding, and then two-stage vulcanization to make various products. Its products have excellent electrical insulation, anti-arc, corona, electric sparking ability, waterproof, moisture-proof, impact resistance, shock resistance, physiological inertness, gas permeability and other properties. Mainly used in aviation, instrumentation, electronics, marine, metallurgy, machinery, automotive, medical and other departments, can do a variety of shapes of seals, gaskets, tubes, cables, but also human organs, blood vessels, gas permeable membranes and Rubber molds, precision casting release agents, etc.

Room temperature vulcanized silicone rubber (RTV)


    Room temperature vulcanized silicone rubber generally includes two types of condensation type and addition type. The addition molding room temperature glue is based on a linear polysiloxane having a vinyl group as a crosslinking agent, and a hydrogen siloxane is used as a crosslinking agent, and a crosslinking reaction occurs at room temperature to a medium temperature in the presence of a catalyst to become an elastomer. It has good heat resistance, water repellency and electrical insulation, and it has excellent physical and mechanical properties due to the introduction of active end groups, especially in terms of tensile strength, relative elongation and tear strength. Improvement. It is suitable for a variety of vulcanization methods, such as radiation vulcanization, peroxide vulcanization and addition vulcanization, widely used in heat, moisture, electrical insulation, high strength silicone rubber products.


    The condensation type room temperature vulcanization silicone rubber is characterized by a condensation reaction between a silanol group and other active materials, and can be crosslinked into an elastomeric silicone rubber at room temperature. The product is divided into a single component package and a two component package. form. One-component room temperature vulcanized silicone rubber (RTV-1 glue for short) is one of the main products in condensed liquid silicone rubber. Usually formulated from base polymers, crosslinkers, catalysts, fillers and additives. The product is packaged in a sealed hose. It is extruded during use and can be vulcanized into an elastomer after contact with air. It is extremely convenient to use. Vulcanized rubber can be used for a long time in the temperature range of (-60 ~ +200 °C). It has excellent electrical insulation properties and chemical stability. It is resistant to water, ozone and weathering. It has good adhesion to various metals and non-metal materials. Connectivity. Mainly used for the coating of various electronic components and electrical equipment, the encapsulation material is insulated, moisture-proof and shockproof; as a surface protection material for semiconductor devices; it can also be used as a sealant and elastic adhesive.


    Two-component room temperature vulcanized silicone rubber (RTV-2 glue for short) is convenient to use without RTV-1 glue, but its composition ratio is rich and varied. One variety can obtain vulcanized products with various specifications and properties, and can also be deeply vulcanized. Therefore, it is widely used in electrical and electronic, automotive, machinery, construction, textile, chemical, light industry, printing and other industries for insulation, packaging, caulking, sealing, moisture, seismic and production of rollers. In addition, since RTV-2 has excellent mold release property, it is widely used as a soft mold material for the reproduction and manufacture of cultural relics, handicrafts, toys, electronic appliances, mechanical parts, and the like.


    One of the typical applications for silicone sealants is the glass curtain wall. The glass and aluminum alloy frame are bonded by the silicone structural adhesive as the outer wall material, and the expansion joint is made of the silicone weathering adhesive for waterproof sealing. Other applications include perimeter seals for aluminum alloy doors and windows and plastic steel doors and windows, seams for glass mounting and moving grooves, rivets and fixing screws: sanitary wares for kitchens, bathrooms, restrooms, countertops, walls, furniture Waterproof seal; aquarium, ceiling, metal roof, window, counter, siding, color steel plate sealing; waterproof caulking seal between high-grade road plates.


    In addition to building sealants, RTV also includes sealing materials for aerospace, nuclear power plants, electronics, machinery, automotive and other industries, silicone potting materials for electronic component potting, and silicones for soft mold materials. Mold glue, etc. The demand for these varieties is relatively small, but in many cases it is indispensable.


  Inorganic silica gel (silica gel)


    Inorganic silica gel is a highly active adsorbent material, usually prepared by reacting sodium silicate and sulfuric acid, and undergoing a series of post-treatment processes such as aging and acid foaming. Silica gel is an amorphous substance with a chemical formula of mSiO2. nH2O. It is insoluble in water and any solvent, non-toxic and tasteless, chemically stable, and does not react with any substance except strong alkali and hydrofluoric acid. Various types of silica gels have different microporous structures due to their different manufacturing methods.


    The chemical composition and physical structure of silica gel determine that it has many characteristics that are difficult to replace with other similar materials: high adsorption performance, good thermal stability, stable chemical properties, and high mechanical strength. Because of its chemical nature, it is used to make many types of silicone products, such as silicone seals, silicone seals, silicone cookers and so on.


    Silica gel is classified according to its pore size: macroporous silica gel, coarse pore silica gel, B-type silica gel, and fine pore silica gel. Due to the different pore structure, their adsorption properties are different. The coarse pore silica gel has a higher adsorption amount in the case of high relative humidity, and the fine pore silica gel absorbs more than the coarse pore silica gel in the case of low relative humidity, while the B type silica gel is thick and thin due to the pore structure. The amount of adsorption between the pores is also between the coarse and fine pores. Macroporous silica gel is generally used as a catalyst carrier, a matting agent, a toothpaste abrasive, and the like.


    From the classification of silica gel, silicone rubber raw materials, liquid silicone rubber raw materials, application characteristics and precautions, there will be different differences. The application technology and main application of silicone raw materials, liquid silicone rubber raw materials are well known, we can have more More to discover, research and explore. Learn about silica gel.


    Silicone resin is mainly used as insulating varnish (including varnish, enamel, paint, varnish, etc.) to impregnate H-class motor and transformer coil, and is used to impregnate glass cloth, glass cloth and asbestos cloth to make motor sleeve and electrical insulation winding. Wait.


    Silicone resin can be used as heat-resistant and weather-resistant anti-corrosion coating, metal protective coating, waterproof and moisture-proof coating for construction engineering, mold release agent, adhesive and secondary processing into silicone plastic for use in electronics, electrical and defense industries. Insulation materials for semiconductor packaging materials and electronic components.


    Silicone resin can also be used as heat-resistant and pressure-resistant anti-corrosion coating, metal protective coating, waterproof and moisture-proof coating for construction engineering, mold release agent, adhesive and secondary processing into silicone plastic for use in electronics, electrical and defense industries. .


    Compared with other silicone materials, there are relatively few silicone resins and a small market share.


    Using pure silicone resin or modified silicone resin as the base material, the silver paint with aluminum powder can be used at a temperature of 400-450 ° C or even 600 ° C. Compared with general organic resins, silicone resins have excellent weather resistance, and the wavelength spectrum released by solar spectrum is more than 300 nm, while silicone absorbs only light below 280 nm.


    The hydrolysis of silicone resin often includes two or more monomers having different hydrolysis rates. In order to flatten the difference in hydrolysis rate of different silanes, uniform co-hydrolysis conditions are caused, usually by simultaneous hydrolysis and alcoholysis.