The difference between silicone and silicone rubber

_{"Silica gel" we sometimes call it silicone,silicone rubber. What is the difference between silicone rubber and silicone? Silicone contains silicone rubber, which belongs to the organic “silica gel” in “silica gel”. Silica gel can be divided into organic silica gel and inorganic silica gel according to its nature and composition.}

_{Silicone rubber performance and technical parameters}

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

The main performance and application 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 rubber is mainly used to manufacture various silicone rubber products, while room temperature rubber is Mainly used as an adhesive, potting material or mold.

Hot vulcanized silicone rubber (HTV)

Hot vulcanized silicone rubber (HTV) is the most important category of silicone products, and methyl vinyl silicone rubber (VMQ) is the most important variety in HTV, commonly known as high temperature adhesive. Methyl vinyl silicone rubber (raw rubber) is a colorless, odorless, non-toxic, and free of mechanical impurities. Raw rubber is mixed with appropriate reinforcing agents, structure control agents, vulcanizing agents and other additives as needed. Refining, then temperature-rising compression molding or extrusion molding, and then made into various products through two-stage vulcanization. Its products have excellent electrical insulation, strong resistance to arcing, corona and electric spark, waterproof, moisture-proof, impact resistance, shock resistance, physiological inertia, breathability and other properties. Mainly used in aviation, instrumentation, electronic appliances, nautical, metallurgy, machinery, automobile, medical and health departments. It can be used in various shapes of sealing rings, gaskets, pipes, cables, as well as human organs, blood vessels, breathable films Rubber mold, precision casting release agent, etc.

Room temperature vulcanized silicone rubber (RTV)

Room temperature vulcanized silicone rubber generally includes two types of condensation and addition molding. Additive room temperature glue is based on linear polysiloxane with vinyl as the base glue and hydrogen-containing siloxane as the cross-linking agent. In the presence of the catalyst, cross-linking reaction occurs at room temperature to medium temperature to become an elastomer. It has good heat resistance, hydrophobicity, electrical insulation, and due to the introduction of active end groups, it has excellent physical and mechanical properties, especially in 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 molding vulcanization, and is widely used in heat resistance, moisture resistance, electrical insulation, high-strength silicone rubber products, etc.

Condensation type room temperature vulcanized silicone rubber is characterized by the condensation reaction between silicon hydroxyl groups and other active substances. It can be cross-linked at room temperature to become an elastomeric silicone rubber. The products are divided into single-component packaging and two-component packaging form. One-component room temperature vulcanized silicone rubber (RTV-1 rubber for short) is one of the main products in condensation type liquid silicone rubber. It is usually formulated from basic polymers, cross-linking agents, catalysts, fillers and additives. The product is packaged in a sealed hose, extruded during use, and vulcanized into an elastomer by contact with air, which is extremely convenient to use. Vulcanized rubber can be used for a long time in the temperature range (-60 ～ + 200 ℃), has excellent electrical insulation properties and chemical stability, can withstand water, ozone, weathering, and has good adhesion to various metal and non-metal materials Connectivity. It is mainly used for coating various electronic components and electrical equipment. The encapsulating material plays the role of insulation, moisture-proof and shock-proof; it is used as the surface protection material of semiconductor devices; it can also be used as sealant and elastic adhesive.

Two-component room temperature vulcanized silicone rubber (RTV-2 rubber for short) is not convenient to use in RTV-1 rubber, but its component ratio is rich in changes. One variety can obtain vulcanized products with various specifications and performance, and it can also be deeply vulcanized Therefore, it is widely used as insulation, encapsulation, caulking, sealing, moisture-proof, anti-vibration and roller-making materials in electronic and electrical appliances, automobiles, machinery, construction, textile, chemical industry, light industry, printing and other industries. In addition, because 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 glass curtain walls. The glass and aluminum alloy frame are bonded with silicone structural adhesive as the external wall material, and the expansion joint is sealed with silicone weatherproof adhesive for waterproofing. Other applications include sealing of aluminum alloy doors and windows and plastic steel doors and windows, sealing of glass installation and moving grooves, sealing of rivets and fixing screws: sanitary ware and countertops for kitchens, bathrooms, toilets, walls, furniture Waterproof seal between aquariums, ceilings, metal roofs, windows, counters, wall panels, and color steel plates; used for waterproof caulking and sealing between high-grade highway plates.

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

From the product classification, application characteristics and precautions of silicone rubber, silicone rubber raw materials and liquid silicone rubber raw materials, there will be differences. The application technology and main application of silicone rubber raw materials and liquid silicone rubber raw materials are well known. More to discover, research and explore to understand silicone.

Inorganic silica gel (silica gel)

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

The chemical composition and physical structure of silica gel determine that it has many characteristics that are difficult to replace by 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 kitchenware and so on.

According to the size of its pore size, silica gel is divided into: macroporous silica gel, coarse pore silica gel, B type silica gel, fine pore silica gel. Due to the different pore structures, their adsorption properties have their own characteristics. Coarse pore silica gel has a higher adsorption capacity when the relative humidity is high, and fine pore silica gel has a higher adsorption capacity than coarse pore silica gel when the relative humidity is low, while type B silica gel has a pore structure between coarse and fine Between the pores, the amount of adsorption is also between the coarse and fine pores. Macroporous silica gel is generally used as catalyst carrier, matting agent, toothpaste abrasive, etc.