SILICA

White carbon black is white powderX-Amorphous rays Silicic acid and Silicate The general term for products, mainly refers to Precipitated Silica 、Fumed silica and ultrafine silica gel, also synthetic in powder form Aluminum silicate and Calcium silicate etc. White carbon black is a porous substance that exists in the form of surface hydroxyl groups. It can be dissolved in Caustic Soda and Hydrofluoric acid ，Insoluble in water, solvents and acids (except hydrofluoric acid). High temperature resistant, non-flammable, tasteless, odorless, with good Electrical insulation 。

use

Due to a series of advantages of white carbon black products, it can be widely used in many fields.

Rubber products

White carbon black is used in colored rubber products to replace carbon black for reinforcement, meeting the needs of white or translucent products. White carbon black also has super strong adhesion, tear resistance, heat resistance and anti-aging properties, so it can also replace part of carbon black in black rubber products to obtain high-quality rubber products, such as off-road tires, engineering tires, radial tires, etc.

Agricultural chemicals

In agricultural chemicals, such as pesticides, high-efficiency spray fertilizers, etc., white carbon black is used as a carrier or diluent, disintegrant, and used as a disintegrant in water-dispersible granules to increase the suspension rate. The recommended content is about 10%. It can maintain long-lasting effectiveness because its ultra-high surface area has extremely high adsorption capacity, is easy to suspend, has good affinity and chemical stability. Even under rain, flushing and hot conditions, it can remain unchanged for a long time.

Daily chemical products

Transparent colored and opaque toothpaste using white carbon black as filler and abrasive, this type of toothpaste has good flexibility and dispersibility, the paste is smooth, soft, and has good abrasiveness, and does not abrade the toothpaste tube; it can keep the medicinal properties of medicated toothpaste stable. In particular, it has good compatibility with fluoride, which can avoid the disadvantage of calcium salt as abrasive to produce insoluble salt.

Binder

Used in adhesives made of natural rubber or synthetic rubber, it provides thixotropy and reinforcement. At the same time, due to its stretchability, it can also improve adhesion. It is of high quality and low price.

Anti-caking agent

Silica can be used to improve free flow in some products, such as lawn fertilizers, fungicides, grinding wheel abrasives, laundry bleach, phenolic injection molding hexamethylenetetramine, phenol and urea plastic products, manufacturing rubber sulfur and anti-caking mixtures.

Papermaking filler

Using white carbon black as paper filler can improve the paper's ink penetration resistance and mechanical strength, increase whiteness, and reduce unit weight. It can effectively achieve paper lightweighting, reduce production costs, and improve paper performance.

In addition, it can also be used in many industries such as fire extinguishing agents, feed, cosmetics, matting agents, pigments, paints, etc.

Gas Phase Applications

Fumed silica is one of the extremely important high-tech ultrafine inorganic new materials. Due to its small particle size, it has a large specific surface area, strong surface adsorption, large surface energy, high chemical purity, good dispersion performance, and special properties in thermal resistance and electrical resistance. With its superior stability, reinforcement, thickening and thixotropy, it has unique characteristics in many disciplines and fields and plays an irreplaceable role. Fumed silica, commonly known as "nano silica", is widely used in various industries as an additive, catalyst carrier, petrochemical, decolorizer, matting agent, rubber reinforcement agent, plastic filler, ink thickener, metal soft polishing agent, insulation and thermal insulation filler, high-end daily cosmetics filler and spraying material, medicine, environmental protection and other fields. It also provides a new material foundation and technical guarantee for the development of related industrial fields. Because it shows special functions compared with conventional materials in terms of magnetism, catalysis, light absorption, thermal resistance and melting point, it has received great attention. The following are the applications of fumed silica in various industries

Electronic packaging materials

Organic electroluminescent device (OLED）It is a new type of flat panel display device that has been recently developed and manufactured. It has low start-up and driving voltages, can be driven by DC voltage, can match large-scale integrated circuits, is easy to achieve full color, and has high luminous brightness (>105CD/Square meters and other advantages, butOLEDThe service life of the device cannot meet the application requirements. One of the technical difficulties that needs to be solved is the packaging materials and packaging technology of the device. At present, foreign countries (Japan, the United States, Europe, etc.) widely use silicone-modified epoxy resins, that is, through the blending, copolymerization or grafting reaction between the two, it can reduce the internal stress of the epoxy resin and form intramolecular toughening, improve the high temperature resistance, and also improve the waterproof, oil-proof and anti-oxidation properties of silicone. However, it takes a long time to cure (several hours to several days). To speed up the curing reaction, it is necessary to cure at a higher temperature (60℃Up to 100℃The use of curing agent will not only increase the cost, but also make it difficult to meet the requirements of large-scale device production lines for packaging materials (short time, room temperature packaging). The surface-active treated fumed silica is fully dispersed in the silicone-modified epoxy resin encapsulation glue matrix, which can greatly shorten the curing time of the packaging material (2.0-2.5h）,And the curing temperature can be lowered to room temperature,OLEDThe sealing performance of the device is significantly improved, increasingOLEDThe service life of the device.

Resin composite materials

Resin-based composite materials have the characteristics of light weight, high strength, and corrosion resistance. However, the current material industry and the pillar industries of the national economy have increasingly higher requirements for the performance of resin-based materials. How to synthesize high-performance resin-based composite materials has become an important issue in the current material industry and the business community. The advent of fumed silica provides new opportunities for the synthesis of resin-based composite materials and a new way to modify traditional resin-based materials. As long as the fumed silica particles can be fully and evenly dispersed in the resin material, the purpose of comprehensively improving the performance of the resin-based material can be achieved.

1、Improve strength and elongation. Epoxy resin is a basic resin material. Adding fumed silica to epoxy resin is completely different from epoxy resin-based composite materials added with macrocrystalline silica (white carbon black, etc.) in structure. Macrocrystalline silica is generally added as a reinforcing agent, and it is mainly distributed between the chains of polymer materials. Fumed silica, due to its serious surface coordination deficiency, huge specific surface area, and surface oxygen deficiency, shows extremely strong activity, and it is easy to form a bond with the oxygen of epoxy ring molecules, thus improving the bond force between molecules. At the same time, a part of fumed silica particles are still distributed in the gaps of polymer chains, and compared with macrocrystalline silica particles, they show high rippling properties, thereby greatly improving the strength, toughness, and ductility of epoxy resin materials added with fumed silica.

2、Improve wear resistance and improve the finish of the material surface. Fumed silica particles are 100-1000 times smaller than silica. Adding them to epoxy resin is conducive to drawing into wires. Due to the high fluidity and small size effect of fumed silica, the surface of the material is denser and cleaner, the friction coefficient is reduced, and the high strength of nanoparticles greatly enhances the wear resistance of the material.

3、Anti-aging performance. A fatal weakness of epoxy resin-based composite materials during use is poor anti-aging performance. The main reason is the effect of medium and long waves of ultraviolet rays in the 280-400 nanometer band of solar radiation, which has a very serious destructive effect on resin-based composite materials. The degradation of polymer chains causes the resin-based composite materials to age rapidly. Fumed silica can strongly reflect ultraviolet rays. Adding it to epoxy resin can greatly reduce the degradation of epoxy resin by ultraviolet rays, thereby achieving the purpose of delaying material aging.

plastic

By using the light-transmitting and small particle size of fumed silica, plastics can be made denser. After adding fumed silica to polystyrene plastic film, not only its transparency, strength, and toughness are improved, but also its waterproof and anti-aging properties are significantly improved. By adding a small amount of fumed silica to ordinary plastic polyvinyl chloride, the hardness, smoothness and anti-aging properties of plastic steel doors and windows are greatly improved. By using fumed silica to modify ordinary plastic polypropylene, the main technical indicators (water absorption, insulation resistance, compression residual deformation, flexural strength, etc.) all reach or exceed the performance indicators of engineering plastic nylon 6, realizing the use of polypropylene railway accessories to replace nylon 6, and the product cost is greatly reduced, and its economic and social benefits are very significant.

coating

my country is a large country in the production and consumption of coatings, but the current domestic coatings generally have performance deficiencies, such as poor suspension stability, poor thixotropy, poor weather resistance, poor scrub resistance, etc., resulting in the need to import a large amount of high-quality coatings every year. Some coating manufacturers in Shanghai, Beijing, Hangzhou, Ningbo and other places have dared to innovate and successfully realized the application of fumed silica in coatings. This nano-modified coating has changed the shortcomings of previous products. After testing, its main performance indicators have been greatly improved except for the contrast ratio. For example, the scrub resistance of exterior wall coatings has been increased from more than 1,000 to more than 10,000, and the artificial accelerated climate aging and artificial radiation exposure aging time have been increased from the original 250 hours (powdering level 1, discoloration level 2) to 600 hours (no powdering, no discoloration of the paint film, color difference value 4.8). In addition, the bonding strength between the coating film and the wall has been greatly improved, the coating film hardness has been significantly increased, and the surface self-cleaning ability has also been improved.

rubber

Rubber is an elastomer with excellent elasticity, but its comprehensive performance is not satisfactory. In the process of producing rubber products, carbon black is usually added to the rubber to improve strength, wear resistance and aging resistance, but the addition of carbon black makes the products black and of low grade. The advent of fumed silica in my country has laid a material foundation for the production of a new generation of rubber products with novel colors and excellent performance. After adding a small amount of fumed silica to ordinary rubber, the strength, wear resistance and aging resistance of the product reach or exceed those of high-end rubber products, and the color can be kept unchanged for a long time. The wear resistance, tensile strength, folding resistance and aging resistance of nano-modified colored EPDM waterproof membrane are significantly improved, and the color is bright and the color retention effect is excellent. The research and development of colored tires has also made certain progress. For example, the folding resistance of the tire side rubber has been increased from 100,000 times to more than 500,000 times. It is expected that in the near future, the color of domestic automobile and motorcycle tires will be realized.

Color (dye) material

Although organic pigments (dyes) have bright colors and strong tinting power, their light resistance, heat resistance, solvent resistance and migration resistance are generally inferior to those of inorganic pigments. By adding fumed silica to modify the surface of organic pigments (dyes), not only the anti-aging performance of the pigments (dyes) is greatly improved, but also the brightness, hue and saturation are also improved to a certain extent. The performance is comparable to that of imported high-end products, which greatly broadens the grade and application range of organic pigments (dyes).

ceramics

Adding fumed silica to 95 porcelain instead of nano-alumina can not only play the role of nanoparticles, but also be the second phase particles, which not only improves the strength and toughness of ceramic materials, but also improves the hardness and elastic modulus of materials. Its effect is more ideal than adding alumina. Using fumed silica to composite ceramic substrates not only improves the density, toughness and smoothness of the substrates, but also greatly reduces the sintering temperature. In addition, the application effect of fumed silica in ceramic filter screens, corundum balls and other ceramic products is also very significant.

Sealants, adhesives

Sealant and adhesive are important products with large quantity, wide application and wide range of applications. They require the product viscosity, fluidity and curing speed to reach the best conditions. Our products in this field are relatively backward, and high-end sealants and adhesives rely on imports. Foreign products in this field have adopted nano materials as modifiers, and fumed silica is the preferred material. It mainly coats a layer of organic material on the surface of fumed silica to make it hydrophobic. When it is added to the sealant, a silica structure is quickly formed, that is, small nano silicon oxide particles form a network structure to inhibit the flow of colloids, accelerate the curing speed, and improve the bonding effect. Due to the small size of fumed silica particles, the sealing and impermeability of the product are also increased.

Fiberglass products

Although FRP products have advantages such as light weight, high strength and corrosion resistance, they have low hardness and poor wear resistance. Relevant experts added fumed silica to gel coat resin by ultrasonic dispersion method and compared the performance of gel coat without fumed silica. They found that its Mohs hardness increased from 2.2 (equivalent to the hardness of gypsum) to 2.8.~2.9Level (Level 3 is the hardness of natural marble), wear resistance increased by 1~2times, because the nanoparticles and organic polymers produce grafting and bonding, the toughness of the material is increased, so the tensile strength and impact strength are increased by more than 1 times, and the heat resistance is also greatly improved.

Drug carrier

With the current substantial increase in urban domestic waste and the increasingly serious environmental pollution, it is urgent to increase the efforts to eliminate the "four pests" and prevent the spread of diseases. Painting lime on tree trunks and spraying medicine on garbage bins are no longer effective. Currently, large cities have adopted spraying central nervous system anesthetic insecticides to eliminate mosquitoes, flies, cockroaches and other insect pests, but these insecticides are mostly imported from abroad, with high prices and short validity periods after spraying (only one month). Using fumed silica as a carrier to adsorb such insecticides has a good slow-release effect. According to measurements, its validity period after spraying is more than one year.

cosmetic

For cosmetics, it is required to have strong UV shielding ability, preferably to protect against UV medium waves (UVB）Harm to human body, and also to long-wave ultraviolet (UVA）Play a protective role. In essence, UV shielding includes two aspects, one is the absorption of ultraviolet rays as mentioned above, and the other is the reflection of ultraviolet rays. At present, there is no report on the anti-ultraviolet agent developed from the perspective of ultraviolet reflection performance in the world. In the past, organic compounds were mostly used as ultraviolet absorbers in sunscreen products, but there are problems such as increasing the amount of addition to protect the skin from ultraviolet rays as much as possible, which will increase the incidence of skin cancer and chemical allergies. Fumed silica is an inorganic component, which is easy to be compatible with other components of cosmetics. It is non-toxic and tasteless, and does not have the above problems. It is white in itself and can be easily colored. What is particularly valuable is that fumed silica has a strong ability to reflect ultraviolet rays and good stability. It does not decompose or change color after being irradiated by ultraviolet rays, and it will not react chemically with other components in the formula. These outstanding characteristics of fumed silica have laid a good foundation for the upgrading of sunscreen cosmetics.

Antimicrobial Materials

Taking advantage of the huge specific surface area, multi-mesoporous surface structure, super strong adsorption capacity and unique physical and chemical properties of fumed silica, functional ions such as silver ions are evenly designed into the mesopores on the surface of fumed silica and stabilized. We have successfully developed a highly efficient, long-lasting, high-temperature resistant, broad-spectrum antibacterial nano-antibacterial powder (particle size is only about 70 nanometers), which not only fills the domestic gap, but also the main technical indicators reach or exceed similar Japanese products. According to testing, when the concentration of nano-antibacterial powder in water is only 0.315%, the antibacterial ability against representative Gram-positive and Gram-negative bacteria can be very clearly revealed, and the inhibition zone appears 2-3 mm, and as the concentration of nano-antibacterial powder in water increases, the inhibition zone increases significantly. According to measurements, the silver content in water is+0.01 mg/When the size is large, it can completely kill the E. coli in the water and prevent the reproduction of new bacteria for up to 90 days. The nano antibacterial powder is applied to enamel glaze to produce a drum washing machine with mildew and antibacterial functions, and its antibacterial rate is as high as over 99%. It should be pointed out that the use conditions of nano antibacterial powder in enamel glaze are relatively harsh. It must be in a highly alkaline liquid and high temperature (900℃After being fired for about 10 minutes, it still maintains strong antibacterial properties, which is unmatched by other antibacterial powders. By adding nano antibacterial powder to interior wall paint, interior wall paint with long-term antibacterial and mildew-proof functions is produced. Nano antibacterial powder is used in women's underwear detergent, wool and cashmere detergent, dishwashing liquid, and hand sanitizer. After testing by the health and epidemic prevention department, its antibacterial properties are very significant. It can be predicted that as people's health awareness increases, nano antibacterial powder will gradually be accepted by the general public of related application enterprises, and will emerge in the bills, medical and health, chemical building materials, home appliances, functional fibers, plastic products and other industries.

other

Application in the field of optics Nanoparticles are mainly used in infrared reflective materials to make thin films and multilayer films. Nanoparticle film materials have good application prospects in the light bulb industry. High-pressure sodium lamps and various iodine arc lamps used for photography and photography require strong lighting, but 69% of the energy of the filament is converted into infrared after being heated, which means that a considerable amount of electrical energy is converted into heat energy and consumed, and only a small part is converted into light energy for lighting. At the same time, the heating of the lamp tube will also affect the life of the lamp. How to improve the luminous efficiency and increase the illumination has always been a key problem to be solved. The birth of nanoparticles provides a new way to solve this problem. Since the 1980s, scientific and technical personnel have used nano-silicon oxide and nano-titanium dioxide particles to make multilayer interference films with a total thickness of microns, which are lined on the inner wall of the bulb cover. As a result, it not only has good light transmittance, but also has strong infrared reflection ability. According to experts' calculations, under the same light brightness, this type of lamp can save 15% of electricity compared with traditional halogen lamps.