Silicone rubber has been widely used, but the understanding of silicone rubber and silica gel on the distinction may be someone do not understand, called the law is not fixed. Today Xiaobian here details the difference and classification of silicone and silicone rubber. At present, the concept of "silica gel" is not standardized, because there is no country only expressly called the law. When we hear the word "silica gel" must understand when it is silicon dioxide or silicon-containing synthetic rubber, or in the end is inorganic silica gel or organic silicone.
"Silicone" is called several related words: silicone rubber, silicone, silicone Silicone rubber and the relationship between silicone, silicone and silicone rubber, silicone rubber is "silicone" inside the organic "silicone". "Silicone" is Hong Kong and Taiwan, in mainland China called "silicone", silicone and silicone is the English transliteration of silicone, we usually say it also refers to "silicone".
In summary, silica gel according to its nature and components can be divided into two categories of organic silica gel and inorganic silica gel.
First, the performance of silicone rubber technical parameters
Silicone rubber is the most widely used silicone products in a wide range of products. Silicone rubber vulcanization has excellent resistance to high, low temperature, weather resistance, hydrophobic, electrical insulation, physiological inertia and so on.
Silicone rubber products, the main performance and application: Silicone rubber vulcanization temperature, can be divided into high temperature (heating) vulcanization and room temperature vulcanization of two categories, high temperature rubber is mainly used in the manufacture of various silicone rubber products, Mainly used as a binder, potting material or mold.
Hot vulcanized silicone rubber (HTV)
Thermal vulcanized silicone rubber (HTV) is the most important category of silicone products, methyl vinyl silicone rubber (VMQ) is the most important varieties of HTV, commonly known as high temperature glue. Methyl vinyl silicone rubber (raw rubber) is colorless, odorless, non-toxic, no mechanical impurities in the jelly, raw rubber as needed by adding the appropriate reinforcing agent, structural control agent, curing agent and other additives mixed together Refining, and then temperature molding or extrusion molding, and then by the two-stage vulcanization made of various products. Its products have excellent electrical insulation, anti-arc, corona, spark ability, waterproof, moisture, impact resistance, good shock resistance, with a physiological inertia, permeability and other properties. Mainly used in aviation, instrumentation, electronic appliances, navigation, metallurgy, machinery, automobiles, medical and health departments, can do all kinds of shapes of seals, gaskets, tubes, cables, but also do human organs, blood vessels, breathable film and Rubber mold, precision casting of the release agent.
Room temperature vulcanized silicone rubber (RTV)
Room temperature vulcanized silicone rubber generally includes two types of condensation and addition. The addition-type room temperature glue is based on the linear polysiloxane with vinyl as the base rubber, with hydrogen sulfide as the crosslinking agent, in the presence of catalyst at room temperature to the temperature of the cross-linking reaction and become elastomers. It has good heat resistance, hydrophobicity, electrical insulation, and has excellent physical and mechanical properties due to the introduction of active end groups, especially in tensile strength, relative elongation and tear strength The improvement. It is suitable for a variety of curing methods, such as radiation curing, peroxide vulcanization and addition vulcanization, widely used in heat, moisture, electrical insulation, high-strength silicone rubber products and so on.
Condensed room temperature vulcanized silicone rubber is a siloxane and other active substances between the condensation reaction is characterized at room temperature can be cross-linked into an elastomer silicone rubber, the product is divided into two-component packaging and two-component packaging two form. One-component room temperature vulcanized silicone rubber (RTV-1 glue) is one of the main products of condensed liquid silicone rubber. Usually from the base polymer, crosslinking agents, catalysts, fillers and additives such as the preparation. Product packaging in the sealed hose, the use of extrusion, contact with the air after the self-vulcanization of elastomers, the use of extremely convenient. Vulcanized rubber in the (-60 ~ +200 ℃) temperature range of long-term use, with excellent electrical insulation properties and chemical stability, water, ozone resistance, weather aging, a variety of metal and non-metallic materials have a good stick Connectivity. Mainly used for a variety of electronic components and electrical equipment coating, encapsulation materials from the insulation, moisture, shock effect; as a semiconductor device surface protection material; also can be used as sealing gap filler and elastic adhesive.
Two-component room temperature vulcanized silicone rubber (RTV-2 glue) is not used on the RTV-1 glue is convenient, but the proportion of its composition is full of changes, a variety can be a variety of specifications of the performance of vulcanized products, but also deep curing, Which 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 roller material. In addition, since the RTV-2 has excellent releasability, it is widely used as a soft mold material for the reproduction and manufacture of cultural relics, handicrafts, toys, electronic appliances, and mechanical parts.
One of the typical applications of silicone sealants is the glass curtain wall. The glass and aluminum alloy frame with silicone structure adhesive as the external wall material, expansion joints are made of silicone weathering glue waterproof seal. Other applications include the use of aluminum alloy doors and windows and plastic doors and windows of the surrounding seal, glass installation and mobile groove patchwork, rivets and fixed screws: kitchen, bathroom, toilet sanitary ware and table, wall, furniture Waterproof seal; aquarium, ceiling, metal roof, window, counter, wall panels, color steel plate seal; for high-grade highway between the sections of the waterproof seal.
RTV in addition to building sealants, but also for aerospace, nuclear power plants, electronics, machinery, automotive and other industries sealing materials for electronic components potting of silicone potting material, used as soft silicone materials Mold glue and so on. The demand for these varieties is relatively small, but in many cases it is essential.
Inorganic Silicone (Silicone)
Inorganic silica gel is a highly active adsorption material, usually with sodium silicate and sulfuric acid reaction, and aging, acid bubble and a series of post-processing process and obtained. Silica is an amorphous material, the chemical formula for the mSiO2. nH2O Insoluble in water and any solvent, non-toxic and tasteless, stable chemical properties, in addition to alkali, hydrofluoric acid does not react with any substance. Various types of silica gel because of its different manufacturing methods to form a different microporous structure.
The chemical composition and physical structure of silica gel, it has many other similar materials difficult to replace the characteristics of high adsorption performance, good thermal stability, chemical stability, high mechanical strength and so on. Because of its chemical nature, so use it to do a lot of types of silicone products, such as silicone seals, silicone seal, silicone kitchen utensils and so on.
Silica gel according to the size of its pore size is divided into: macroporous silica gel, coarse silica gel, B type silicone, fine silica gel. Due to the different pore structure, their adsorption properties are characteristic. In the case of relatively high relative humidity, the silica gel has a higher adsorption capacity than that of the coarse silica gel in the case of relatively low relative humidity, while the B-type silica gel is composed of coarse and fine Hole between the adsorption capacity is also between the coarse, between the pores. Macroporous silica gel is generally used as catalyst carrier, matting agent, toothpaste abrasive and so on.
From the silicone rubber, silicone rubber raw materials, liquid silicone rubber raw materials, product classification, application characteristics and precautions, there will be their own different, silicone raw materials, liquid silicone rubber raw materials, application technology and the main application of familiar, we can More to discover, study and explore. Learn about silica gel.
Silicone resin is mainly used as insulation varnish (including varnish, enamel, paint, varnish, etc.) impregnated H-class motor and transformer coil, and used to impregnate glass cloth, glass cloth and asbestos cloth made after the motor sets, electrical insulation winding Wait.
Silicone resins can be used as heat-resistant, weather-resistant anticorrosive coatings, metal protective coatings, architectural waterproofing and moisture proofing coatings, release agents, adhesives and secondary processing into silicone plastics for use in electronics, electrical and defense industries. Semiconductor packaging materials and electronic components of the insulation materials.
Silicone resin can also be used as heat-resistant, pressure-resistant anti-corrosion coatings, metal protective coatings, waterproofing waterproofing coatings, release agents, adhesives and secondary processing into silicone plastics for the electronics, electrical and defense industries The
Compared with other silicone materials, silicone varieties are relatively small, the market share is small.
The use of pure silicone resin or modified silicone resin as a base material, add aluminum powder silver paint can be used the corresponding temperature of 400-450 ℃, or even 600 ℃. Compared with the general organic resin, silicone resin has excellent weatherability, the wavelength spectrum of the solar spectrum is more than 300nm, while the silicone absorbs only 280nm below the light.
Hydrolysis of the silicone resin often involves two or more monomers with different hydrolysis rates. In order to flatten the difference in the rate of hydrolysis of the different silanes, uniform co-hydrolysis conditions are caused, usually in the same manner as hydrolysis and alcoholysis.