Silicone rubber is widely used, but some people may not be able to distinguish between silicone rubber and silica gel, and the name has not been decided. Today, the editor will take a closer look at the differences and classifications between silicone and silicone rubber. Currently, the concept of the term “silicone” is not standardized. So far, there is no well-defined name. When you hear the word “silica gel”, you need to understand whether it is silica gel or silicone-containing synthetic rubber, or whether it is inorganic silica gel or organic silica gel in the final analysis.
“Silica gel” is referred to by several related terms such as silicone rubber, silicone rubber, and silicone. The relationship between silicone rubber and silica gel is different from silicone rubber and includes silicone rubber. Silicone rubber is an organic “silica gel” of “silica gel”. “Silicone” is a term used in Hong Kong and Taiwan. It is called “silicone” in mainland China. Silicone and Silicone are transliterations of English silicone. It is usually said that it also means “silicone”.
In summary, silica gel can be divided into two categories, organic silica gel and inorganic silica gel, according to their properties and composition. First, I will explain about silicone rubber.
1. Silicone rubber performance and technical parameters
Silicone rubber is the largest and most widely used category of silicone products. After vulcanization, silicone rubber has excellent heat resistance, low temperature resistance, weather resistance, water repellency, electrical insulation, and physiological inertia.
Key Properties and Applications of Silicone Rubber Products: Depending on their vulcanization temperature, silicone rubber can be divided into two categories: high temperature (heated) vulcanization and room temperature vulcanization. High temperature rubber is mainly used in the manufacture of various silicone rubber products, while room temperature rubber is mainly used as adhesives, potting materials and molds.
Hot vulcanized silicone rubber (HTV)
Heat vulcanized silicone rubber (HTV) is the most important category of silicone products, and methyl vinyl silicone rubber (VMQ) is the most important category of HTV commonly known as high temperature rubber. Methyl vinyl silicone rubber (raw rubber) is colorless, odorless, non-toxic and free of mechanical impurities. Raw rubber is mixed with appropriate reinforcements, structural controls, vulcanizers and other additives as needed. Purification, heating, compression or extrusion, followed by two-step vulcanization into a variety of products. Its products have excellent electrical insulation, strong resistance to arcs, coronas, and sparks, waterproof, moisture proof, impact resistance, impact resistance, physiological inertia, breathability and other properties. It is mainly used in aviation, instrumentation, electronics and appliances, navigation, metallurgy, machinery, automobiles, medical and health, and other sectors, and can be used to manufacture seal rings, gaskets, tubes, and cables of various shapes. Human organs, blood vessels, breathable membranes and rubber molds, mold release agents for precision casting, etc.
Room temperature vulcanized silicone rubber (RTV)
RTV silicone rubber generally has two categories: condensed type and additive type. “The additive-type room temperature adhesive is based on a linear polysiloxane having a vinyl group, uses a hydrogen-containing siloxane as a cross-linking agent, and undergoes a cross-linking reaction at room temperature to medium temperature in the presence of a catalyst to become an elastomer. It has excellent water repellency and electrical insulation, and at the same time, it has excellent physical and mechanical properties such as tensile strength, relative elongation, and tear strength due to the introduction of active terminal groups. Radiation sulphurization and peroxide addition. It is suitable for various sulfurization methods such as sulfurization and addition molding sulfurization, and is widely used for heat resistance, moisture resistance, electrical insulation, and high-strength silicone rubber products.
Condensation-type room-temperature vulcanized silicone rubber is characterized by a condensation reaction between silicone hydroxyl and other active materials, and is cross-linked at room temperature to form an elastomer. Products are divided into one-component packaging and two-component packaging. shape. One-component vulcanized silicone rubber (RTV-1 rubber for short) is one of the main products of condensed silicone rubber. It is usually formulated from base polymers, crosslinkers, catalysts, fillers and additives. The product is very convenient because it is packed in a sealed hose, squeezed out during use, exposed to air and then vulcanized into an elastomer. The vulcanized product can be used for a long period of time in the temperature range of (-60 to + 200 ° C), has excellent electrical insulation and chemical stability, has excellent water, ozone, and weather resistance, and has excellent adhesion to various metals. increase. And non-metal materials. Accessibility. It is mainly used for coating various electronic parts and electrical equipment, and plays a role as insulation, moisture proof, impact resistance, surface protection material for semiconductor devices, sealing filler, and elastic adhesive.
Two-component room temperature vulcanized silicone rubber (RTV-2 rubber for short) is not as convenient as RTV-1 rubber, but it has a wide variety of component ratios. Vulcanized products with multiple specifications and characteristics can be obtained with one type. Therefore, it is widely used as a material for insulation, encapsulation, caulking, sealing, moisture proofing, vibration proofing, and roller manufacturing in industries such as electronic equipment, automobiles, machinery, construction, textiles, chemicals, and light industry. , Printing etc. In addition, because RTV-2 has excellent mold releasability, it is widely used as a soft mold material for duplicating and manufacturing cultural properties, handicrafts, toys, electronic devices, and machine parts.
One of the typical uses of silicone sealants is glass curtain walls. The glass and aluminum alloy frames are glued with organic silicon structural adhesive as the material for the exterior walls, the telescopic joints are waterproof and sealed with organic silicon weathering adhesive. Other applications include aluminum alloy doors and windows, plastic steel doors and window perimeter sealing, glass mounting and moving groove joints, rivet and fixing screw sealing: sanitary ware and countertops, Waterproof seals between walls, kitchens, bathroom furniture, aquariums, ceilings, metal roofs, showcases, counters, wall panels, colored steel plates. Used for waterproof caulking seals between highway plates.
In addition to construction sealants, RTV includes sealing materials used in industries such as aerospace, nuclear power plants, electronic equipment, machinery, and automobiles, silicone potting materials used for potting electronic components, and soft mold materials. Includes silicone mold adhesives used. .. Demand for these varieties is relatively low, but in many cases they are essential.
Inorganic silica gel (silica gel)
Inorganic silica gel is a highly active adsorbent, usually prepared by reacting sodium silicate with sulfuric acid and undergoing a series of post-treatment processes such as aging and acid foaming. Silica gel is an amorphous substance and its chemical formula is mSiO2. nH2O. It is insoluble in water and solvents, non-toxic, tasteless, chemically stable, and does not react with substances other than strong alkalis and hydrofluoric acid. Different types of silica gel are manufactured differently and form different microporous structures.
The chemical composition and physics of silica gel determine that it has many properties that are difficult to replace with other similar materials: high adsorption performance, excellent thermal stability, stable chemistry, and stable chemistry. High mechanical strength. Due to its chemical properties, it is used in the manufacture of various types of silicone products such as silicone seals, silicone seals and silicone kitchen utensils.
Silica gel is divided into macroporous silica gel, course pore silica gel, type B silica gel, and fine pore silica gel according to the size of the pore diameter. Due to the difference in pore structure, the adsorption characteristics have unique characteristics. Coarse-pore silica gel has a higher adsorption capacity when the relative humidity is high, and pore silica gel has a larger adsorption capacity than coarse-pore silica gel when the relative humidity is low. Type B silica gel is between coarse and fine pores, and the amount of adsorption is also between coarse and fine pores. Macroporous silica gel is commonly used as a catalyst carrier, matting agent, toothpaste and abrasive.
The product classifications, application characteristics, and precautions for silica gel, silicone rubber raw materials, and liquid silicone rubber raw materials are different. The application technology and main applications of silica gel raw material and liquid silicone rubber are different. Raw materials are familiar and you can discover, investigate and explore more. Learn about silica gel.
Silicon resin is mainly used as an insulating paint (including varnish, enamel, colored paint, varnish, etc.), impregnated with H-class motors and transformer coils, and impregnated with glass cloth, glass cloth silk, and asbestos cloth. We manufacture motor covers and electrical products. Please wait for the insulated winding.
Silicone resins are heat and weather resistant anticorrosion coatings, metal protective coatings, waterproof and moisture proof coatings for construction projects, release agents, adhesives, and secondary processing to silicone plastics for use in electronics, electrical and defense. Can be used as. industry. Semiconductor packaging materials and insulating materials such as electronic parts.
Silicone resins are heat and pressure resistant anticorrosion coatings, metal protective coatings, waterproof and moisture proof coatings for construction projects, mold release agents, adhesives, and electronics, electrical products, and defense industries.
Compared to other silicone materials, silicone resins have a relatively small variety and small market share.
When pure silicone resin or modified silicone resin is used as the base material, silver paint containing aluminum powder can be used at temperatures of 400-450 ° C and even 600 ° C. Compared to general organic resins, silicone resins have better weather resistance, and the wavelength range of the solar spectrum is 300 nm or more, but silicone resins absorb less than 280 nm.
Hydrolysis of silicone resins often contains two or more monomers with different hydrolysis rates and is usually used to smooth out the differences in hydrolysis rates of different silanes and to achieve uniform co-hydrolysis conditions. , Hydrolysis and alcohol decomposition are performed at the same time.
Post time: Oct-29-2021