Application of silica sol in various industries
Application of silica sol in various industries
After continuous development and research, the application of silica sol in various fields of modern industry has become increasingly widespread
1. Application of silica sol in precision casting
Silica sol is mainly used as a binder for precision casting coatings, and can be used as surface coating and reinforcement coating for mold shells. Applying small particle silica sol to precision casting instead of ethyl silicate can not only reduce costs, but also improve working conditions. When used for thin shell precision casting, it can make the shell with high strength, high dimensional accuracy, good casting finish, good quality than water glass, and cheaper than ethyl silicate. For large castings, castings that require high surface finish and those that require no or small margins are particularly suitable. Using silica sol as a high temperature resistant coating for casting molds can make the coatings have good heat resistance and wear resistance, can reduce the loss of molten metal on the mold at high temperatures, and help demolding.
2. Application of silica sol in textile
In the textile industry, fabrics treated with silica sol have high strength, stable fabric size, and high resilience; the combined use of silica sol and synthetic hair oil increases the cohesion between fibers, increased tensile strength, and improves production efficiency. Spin out high-count products.
In the process of wool spinning, silica sol is used as a sizing aid for diameter spinning to reduce the breaking rate of wool fibers. Containing titanate fiber in the coating, silica sol can increase the surface heat resistance of the inorganic fiber material. The amount of silica sol is generally controlled at 2 to 5%. The best adding state is to add wool and fine short hair at the first start, but the silica sol contains a certain amount of moisture, which must be calculated into the resurgence of the machine.
Adding silica sol to the sizing of the radial yarn can reduce the breakage and save the sizing; when using fine-grain rolling or sizing, the silica sol is added to polyvinyl alcohol, carboxymethyl cellulose, natural starch and oil and other materials In the pulp, the diameter yarn can be easily separated, the anti-skid continuous yarn, the woven nylon wire fishing net has a strong knot, which is not easy to slide and loosen; the nylon rope treated with silica sol can increase the friction between the monofilaments. It is non-slip and can reduce its elongation; futon materials made of synthetic fibers are generally slippery. If you use fibers treated with silica sol, you can get a fluffy, elastic and non-slip bedding. Treatment of chemical fibers with silica sol can also obtain the extinction effect.
Silica sol can also be used in fabric dyeing. Because it is cohesive, it can form an excellent protective liquid, help the pigment adhere to the surface of the fabric, increase the uniformity and fastness of dyeing, and prevent the pigment from agglomerating; add 60% of the silica sol to the starch glue. It is used to treat fabrics, such as carpets, which can be non-slip, dustproof, static electricity, and non-sticky.
Nylon yarn is impregnated in 5% silica sol solution and knitted into socks to prevent or reduce the occurrence of burrs. In short, the range of fabrics that can be treated with silica sol is extremely wide, regardless of various textiles and knitwear, and regardless of fabrics made of nylon viscose fiber, polyester, acetate fiber, polypropylene, etc., the treatment has a good effect.
3. Papermaking
In the production of man-made fibers and cellophane, the use of silica sol as a binder can prevent the adhesion and entanglement between the films; the photosensitive paper is mixed with the silica sol and the photosensitive liquid to make the surface of the photosensitive paper smooth, the image clear, and increase Large exposure range, making one-step imaging paper; pre-coating used for printing paper, copy paper and offset printing, can make the paper smooth, the image contrast is clear, and the contrast is good. After the surface of kraft paper and corrugated paper is treated with silica sol, it can improve the slip resistance of the paper, reduce the slip during transportation and storage, and improve the temperature resistance and strength of the paper products; use silica sol to replace clay and talc in the manufacture of non-carbon carbon paper Powder and silica powder coating can make the color more vivid; plastic film and cellophane are easy to be sticky in summer. If they are treated with a mixture of silica sol and glycerol monostearate, it can be solved satisfactorily. The perforated paper used in electronic computers, coated with silica sol, can make it have higher stability and slip resistance, and good printability.
4. Catalyst
In the production of catalysts, silica sol is used as a carrier to accelerate the catalytic rate under certain conditions to improve production efficiency. Its advantage is that there are no other by-products, salts, etc., and a certain specific surface area can be obtained. At the same time, the content of SiO2 is high, the processing rate is high, and the selectivity and activity are very good. Silica sol with a SiO2 concentration of 40% has been successfully used as a carrier for the production of acrylic cyanide catalyst C-41. Others include benzene oxidation as a carrier for maleic anhydride, synthesis of methyl methacrylate; chlorination of hydrocarbons; dehydrogenation of alcohols, etc. can be used as a carrier. Industrial production often has different requirements for the particle size, specific surface area, pore size, pore volume and rigidity of the catalyst carrier. For example, in the fixed bed reaction, due to the restriction of fluid resistance, the use of large particle carriers is required; in the sulfidation bed, fine particle carriers are required to improve efficiency; the molybdenum bismuth catalyst for the ammonia oxidation requires carrier particles The diameter is about 50 microns; the microsphere catalyst used for the catalytic cracking of petroleum distillates requires a particle size of about 60 microns.
5. Silica sol to make silicon ball
In the mixture of urea and formaldehyde, there are inorganic particles of silica sol (SiO2). Due to the copolymerization of organic urea and formaldehyde, urinary formaldehyde copolymer and colloidal particles in solution are copolymerized to form spherical particles.
6. Petroleum
The use of silica sol as the monomer catalyst in the production of aromatic cyanides opens up a new way to increase the recovery rate of aromatic cyanide. Silica sol is used in several sets of petrochemical complexes introduced in China. In the petroleum industry, silica sol is used as a binder and catalyst.
7. Paint
Silica sol is widely used as exterior wall architectural coating. It has the advantages of water resistance, weather resistance, fire resistance, stain resistance, high temperature resistance, high hardness of the coating film, bright color, and no fading. It can also be used in acid-resistant, alkali-resistant, fire-resistant, water-repellent coatings and infrared radiation coatings.
8. Enamel
In the manufacture of enamelware, the expansion coefficient can be reduced after adding silica sol to improve the adhesion to tetrafluoroethylene. By blending 25-30% silica sol into the glass, high-quality boron silicate glass can be obtained.
9. Battery
The electrolyte sulfuric acid of the lead battery is easy to overflow when turning sharply in automobiles, tanks and other motor vehicles. If a certain amount of silica sol is added to the sulfuric acid to gel it, it can prevent sulfuric acid leakage and overflow, and can extend the life of the battery .
10. Metal
Silica sol can be used to prevent white embroidery of galvanized sheet. Insulation film treatment of electromagnetic steel plate, sealing treatment of anti-corrosion aluminum, surface grinding treatment, oxidation inhibitor during heat treatment.
11. Steel rolling
Adding a certain amount of silica sol to the coating solution can improve the appearance, insulation and heat resistance of the insulating coating, reduce the expansion coefficient of the coating material, and improve the magnetic properties of silicon steel.
12. Broadcasting equipment
Silica sol can be used as a coating for the bonding of picture tubes of TV sets. When it is used as a transformer magnetic core, it is used as a binder to bond silicon steel sheets into one, and it has the effects of insulation, high temperature resistance and melting point increase, and the effect is very good.
13. Use silica sol as the far infrared radiation coating has good adhesion, high temperature resistance, does not affect radiation.
14. Use silica sol as the binder of ceramic fiber, impregnate aluminum silicate fiber felt with silica sol, add accelerator to make warm felt, used as thermal insulation and refractory material, and make the surface of refractory brick of high temperature furnace stick The binder has high bonding strength, high temperature resistance (above 1000 ℃), saves energy, and is economical and convenient for furnace reformation.
15. Polishing agent for original semiconductor
Using large-particle silica sol as a single-crystal silicon polishing agent not only has a good effect, but also has a fast polishing speed.
16. Reinforced foam rubber
Natural rubber and most synthetic rubbers, such as styrene-butadiene rubber, neoprene and mixed rubber, can be reinforced with silica sol. Adding 5% silica sol to the dry rubber can enhance the porous foam rubber by 20%; for a certain volume of rubber, because the elasticity is improved, 20% of the rubber can be saved, and adding silica sol in the beating operation can also Improve foam performance and produce more stable wet foam. In addition, foam rubber can also be prepared first and then treated with silica sol.
17. Silica sol can be used as a clarifying agent for soy sauce and rice wine, and it does not affect the color, aroma and taste. Silicon is non-toxic to humans and has certain anti-cancer and anti-cancer effects.
18. Carbon products treated with silica sol can reduce the loss caused by surface oxidation.
19. Chemical fiber decoration articles treated with silica sol can double the anti-pollution property. It can be seen that silica sol is also an effective anti-fouling agent for surfaces such as wall coverings.
20. The non-slip floor wax made of silica sol has been well-known in industry and civil use. The fine SiO2 particles adhere to the wax film on the floor surface, which has a good anti-slip effect and does not affect the gloss and softness.
21. Silica sol is an excellent water purifier. After it is mixed with aluminum sulfate, the metal salts and suspended turbidity in the water can be coagulated and removed.
22. A small amount of silica sol is added to the fuel oil to prevent the accumulation of burnt ash on the diesel engine.
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