How to classify silica gel, and what role does each have?

发布日期:2021-04-16 15:39:35 浏览次数:

One of the typical applications of silicone sealants is glass curtain walls. The glass and aluminum alloy frame are bonded with organic silicon structural adhesive as the exterior wall material, and the expansion joint is waterproof and sealed with organic silicon weather-resistant adhesive. Other applications include the peripheral sealing of aluminum alloy doors and windows and plastic steel doors and windows, the joints of glass installation and moving grooves, the sealing of rivets and fixing screws: sanitary ware and countertops, walls, and furniture in kitchens, bathrooms, and toilets. Waterproof sealing between the aquariums, ceilings, metal roofs, showcases, counters, wall panels, and color steel plates; used for waterproof caulking and sealing between high-grade highway plates, etc. In addition to sealants for construction, RTV also includes sealing materials used in aerospace, nuclear power plants, electronics, machinery, automobiles and other industries, silicone potting materials used for potting electronic components, and silicone used as soft mold materials Mold glue and so on. The demand for these varieties is relatively small, but they are indispensable on many occasions.

Two-component room temperature vulcanized silica gel (RTV-2 glue for short) is not as convenient as RTV-1 glue, but its component ratio is rich in changes. One variety can obtain vulcanized products with multiple specifications and properties, and it can also be deeply vulcanized. It is widely used as materials for insulation, encapsulation, caulking, sealing, moisture-proof, anti-vibration and roller making in industries such as electronics, automobiles, machinery, construction, textile, chemical, light industry, printing and so on. In addition, because RTV-2 has excellent mold release properties, it is widely used as a soft mold material for the reproduction and manufacture of cultural relics, handicrafts, toys, electronic appliances, and mechanical parts.

Room temperature vulcanized silica gel:

RTV silicone rubber generally includes two categories: condensation type and addition type.

Condensation-type room temperature vulcanized silicone rubber is characterized by the condensation reaction between silicone hydroxyl and other active materials, which can be cross-linked to become elastomers at room temperature. The products are divided into one-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 the condensation type liquid silicone rubber. It is usually formulated from base polymer, crosslinking agent, catalyst, filler and additives. The product is packaged in a sealed hose, squeezed out during use, and can be vulcanized into an elastomer after being exposed to air, which is extremely convenient to use. The vulcanizate can be used for a long time in the temperature range (-60℃ to 200℃), has excellent electrical insulation properties and chemical stability, is resistant to water, ozone, weathering, and has good adhesion to a variety of metal and non-metal materials. Accessibility. It is mainly used for the coating of various electronic components and electrical equipment. The encapsulating material plays the role of insulation, moisture-proof and shock-proof; as a surface protection material for semiconductor devices; also as a sealing filler and elastic adhesive.

The addition-type room temperature glue is based on a linear polysiloxane with vinyl groups and a hydrogen-containing siloxane as a cross-linking agent. In the presence of a catalyst, the cross-linking reaction occurs at room temperature to medium temperature to become an elastomer. It has good heat resistance, water repellency, and electrical insulation. At the same time, 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. It is widely used in heat resistance, moisture resistance, electrical insulation, and high-strength silicone products.

Thermally vulcanized silicone:

Thermally vulcanized silicone rubber (HTV) is the most important category of silicone products, and methyl vinyl silicone rubber (VMQ) is the most important category in HTV, commonly known as high temperature rubber. Methyl vinyl silica gel (raw rubber) is a colorless, odorless, non-toxic, and non-mechanical impurity gel. The raw rubber is mixed with appropriate reinforcing agents, structure control agents, vulcanizing agents and other additives as needed. , And then press molding or extrusion molding at elevated temperature, and then make various products after two-stage vulcanization. Its products have excellent electrical insulation, strong resistance to arc, corona, and spark, waterproof, moisture-proof, impact resistance, shock resistance, physiological inertia, air permeability and other properties.