Research and application of the surface coating fo

2022-08-07
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Research and application of surface coatings for flat glass

by coating organic coatings on the surface of glass, glass will be endowed with more functions and functions For example, the surface coating makes the glass have the ability to control the sunlight, significantly improve the energy utilization rate, so as to achieve the purpose of saving energy; Increase the wear resistance of glass containers (such as drinks or milk bottles), so that the glass surface has a good function of preventing adhesion of rain and snow, so as to give the automobile windshield a good transparency in rainy and snowy weather and avoid traffic accidents; At the same time, paint gives glass products colorful colors The application of coatings in the glass industry mainly includes the following four aspects: flat glass, glass container, glass fiber and special glass. Among them, flat glass coatings are most widely used in modern buildings and home decoration and decoration

1 preparation technology of flat glass coating

in the preparation technology of glass coating, the selection of base resin, the study of film properties (such as durability) and the coating process are the most important

1.1 selection of resin

the special surface structure of glass substrate determines that it is difficult for ordinary organic coatings to adhere to it. Therefore, the glass substrate has some specific requirements for the variety of coating resin

in order to endow glass coatings with multiple functions and functions, a variety of resins are generally selected for compounding For example, liaolong used styrene, acrylic acid and methacrylic acid to invent a new color glass coating with good weather resistance, strong adhesion, impact resistance, water resistance, wear resistance, scrub resistance, convenient construction and appropriate price Wangxinsheng selected acrylic modified resin and epoxy resin to develop a color glass coating with low cost, bright color, good performance and boiling water resistance up to 2.5h

fluoropolymer, as a new material, has good comprehensive properties, especially in hydrophobicity and oil repellency After the mixed solution containing CF3 (CF2) 7 (CH2) 2Si (OME) 3 and Si (OET) 4 is coated on the glass surface, the contact angle between the film and water can reach 110 °; After the mixed solution containing 3-glycerol hydroxypropyl-3-methylsilane me2si (OET) 2, fluorinated alkoxysilane and colloidal SiO2 is formed on the glass surface, the contact angle with water reaches 104 °; Similar contact angles can also be obtained by the film formation of Si (OET) 4 and CF3 (CF2) 7 (CH2) 2Si (OME) 3 on the glass surface According to the properties of these materials, Mori a developed antifouling coatings based on Si (OET) 4, titanium alkoxide and CF3 (CF2) 7 (CH2) 2Si (OME) 3 Kasemann R et al. Prepared a fluoro modified silane solution film with Si (OET) 4 and me2si (OET) 2 as the matrix. When its surface energy was 18mj/m2, the surface energy of the film did not decrease significantly after 500000 cycles of wiping test in a humid environment Adding ZrO2 or SiO2 into the coating system can increase the wear resistance of the film, and the film also has a good dust prevention effect Yoshinori Akamatsu and others developed a hydrophobic coating by using the hydrolysis and polycondensation of fluorinated alkyl trimethoxysilane (FAS) and CF3 (CF2) 7 (CH2) 2Si (OCH3) 3, which can be widely used on automobile windscreens. They also investigated the effect of Fas polymerization on the durability of water repellent glass Schmidt h et al. Chemically modified the coating mixture through 3. The fixture itself is a locking mechanism, and developed a UV curing coating based on 3-Trimethoxysilyl propyl isobutyric acid, Zr (onpr) 4 and isobutyl acid

fluorinated siloxane and chlorinated silane have been applied to single-layer surface treatment, such as polarizer plate treatment of liquid crystal display, super hydrophobic surface coating, hydrophobic and oil repellent coating for aviation equipment, etc However, the high price of fluorine modified materials limits its wide application DuPont has developed a series of fluorocarbon surfactants, mainly to improve film leveling and wetting properties

1.2 durability of coating film

in the application of organic coatings on the surface of glass, durability is the key for organic coatings to improve various properties of glass (mainly the chemical, physical and optical properties of glass)

lee donghun et al. Used drift optical technology to investigate the mechanical interaction between different carboxyl containing polymers and the glass surface, and found that when oleic acid was coated on SLS glass (sodium carbonate/calcium carbonate/silicate glass), the -cooh in oleic acid dissociated and adsorbed on the SLS glass surface, and formed many different kinds of metal chelates After some metal ions such as al3+ and COOH are chelated, they are more firmly bonded to the silicate like structure than other chelating ions such as Na 3, selection index of electronic tensile testing machine +, ca2+ This shows that the kinds of metal ions on the glass surface can determine some properties of the glass surface, such as lubricity and hydrophobicity

humidity in the air and some other side reactions may destroy the interaction between organics and glass, thus changing or reducing the bonding performance, and then affecting the durability of the film Vadim V krongauz et al. Studied the adhesion phenomenon of organic polymer on the glass surface under the influence of high humidity environment through electron microscope, and confirmed that humidity has a great influence on the adhesion of coating film on the glass surface

the scratch resistance and abrasion resistance of the coating on the surface of glassware are also important indicators to measure the quality of the coating In general, the use of a single coating to improve scratch and wear resistance is limited For this reason, hozumi a et al. Developed a double-layer coating with UV curing coating as primer and heat curing coating as topcoat, in order to improve the scratch resistance and wear resistance of the coating The wear test results show that the coating system has strong abrasion resistance and high hardness, which is close to the surface hardness of inorganic glass

to measure the abrasion resistance and scratch resistance of the coating, it is often necessary to conduct scratch test with the help of instruments, such as pencil hardness method, Taber abrasion resistance test method and revitest scratch tester At present, optical microscope, atomic force microscope, scanning electron microscope, X-ray photoelectric spectroscope and other microscopic methods have been widely used to evaluate the microstructure and properties of coating materials

1.3 coating process

the traditional coating process includes brush coating, spraying and dip coating. Later, sol-gel method, electrostatic spraying and electrophoretic method appeared successively As various coating processes have different characteristics, they should be comprehensively considered according to the workpiece material, specification, size, shape, construction environment, quality requirements, coating utilization rate and other factors

sol-gel process, as a new coating process, has been applied to the surface coating of glass for a long time. It has the characteristics of low cost and convenient operation. It can be applied to the surface coating of metal, glass and porcelain At the same time, the coatings prepared by sol-gel technology can significantly improve the mechanical, thermal, optical and electrical properties of the substrate. Such coatings also have the functions of wear resistance, peel resistance, delamination resistance and protection of the substrate from external forces; The outstanding advantage is that it allows the glass to be used below the silicate melting point, It can ensure that the coating has small particle size when forming film on the glass surface (<100nm =, which makes the film uniform, and it is easy to paint the metal oxide coating on the glass substrate. Nikoli l et al. Studied the effect of SiO2 sol-gel coating on the strength of alkali glass substrate. The results showed that the microstructure of SiO2 coating depends on the SiO2 sol structure. Vroon zaep et al. Prepared vanadium oxide and tungsten oxide coatings respectively with alkoxide as solvent. After the two coatings were coated on the surface of k-glass, it was found that the vanadium oxide coating was uniform and consistent, and It has excellent electrochromic properties In vanadium oxide/titanium oxide coatings, when the content of titanium oxide is more than 40%, the power storage capacity of the film can reach 45mc/cm2

at present, sol-gel method can be used to make single component or multi-component coatings, especially organic-inorganic hybrid coatings, transparent conductive and anti-static coatings, fluorinated coatings and dye composite materials. Coating these coatings on the surface of glass can make the glass have the properties of color rendering, anti reflection, selective reflection, selective absorption, sliding and antifouling

2 progress in the application of flat glass coating

2.1 common decorative coating

transparent glass coating has the advantages of solid coloring, no cracking, no falling off, bright color and durability. After it is coated on the surface of flat glass and dried into a film, it can be assembled into various artistic patterns, which are widely used in the decoration of doors, windows and ceilings of various buildings, as well as the curtain wall decoration of high-rise buildings For example, Shi Erya prepared a transparent colored glass coating by mixing st MMA MAA terpolymer with epoxy resin, organic mixed solvent, curing agent and pigment in a certain proportion; Sinha et al. Mixed styrene maleic anhydride copolymer containing carboxyl functional group, acrylic copolymer resin, slip increasing additive and chemical crosslinking agent to prepare an aqueous mixture with a solid content of not less than 10%. The coating can be crosslinked at room temperature to form a smooth and dense film with good wear resistance, hot water resistance and durability The carboxyl group in the copolymer resin can ensure its good dispersibility in water. At the same time, after the crosslinking film is formed, the carboxyl group on the surface of the film makes the film hydrophilic to a certain extent, which makes it easier to paint ink or stick various labels on its surface

2.2 low-E coating

low radiation glass is another new type of energy-saving glass since the 1990s It uses high-tech coating technology to coat a special metal compound film on the glass surface, which can reflect infrared and far-infrared radiation and block the transfer of heat At the same time, the low radiation glass still maintains a good light transmittance, which blocks the heat transfer and does not affect the indoor brightness In order to protect the film layer, low radiation glass is generally made into hollow or laminated glass This makes it the most ideal energy - saving window glass material For example, mengqinglin and others prepared nano thermal insulation coating with nano ATO and waterborne polyurethane through a certain process, and coated it on the glass surface at room temperature to make low radiation glass. The analysis of its optical properties shows that it has good thermal insulation effect. After 6mm thick white glass is coated, the shading coefficient SC is less than 0.67, and the visible light transmittance is higher than 63%, and the glass surface is smooth and flat, with good visibility, which has a good market prospect

at present, almost all low radiation coatings used on glass are silver based coatings However, the low radiation coating coated with silver is poor in durability. In order to ensure that the glass has better transparency to a certain range of visible light and prevent the silver coating from corrosion, it is also necessary to introduce materials with high refractive properties (such as SnO2, ZnO, Si3N4, TiO2) into the coating as anti reflection and protective layers

vacuum coating method has very excellent coating performance in coating low radiation film and sending the signal to the computer. It is less affected by internal environmental factors, so it has an advantage in the coating of glass surface At present, the annual production of insulating glass installation components in the world has reached 200million m2, of which about 30% are low radiation glass coated by vacuum

at present, there are many low radiation glass coatings with different design combinations in the market High light transmittance, high environmental stability and low radiation coatings are the future development direction of glass coatings In the glass industry, the application of low radiation glass in architecture is still very expensive In this way, low - radiation glass coatings still have great room for improvement in terms of optical performance and cost

2.3 antireflection (AR) coating

ar coating is generally composed of single-layer or multi-layer film superposition The single layer only works on the visible light of a certain wavelength, while the multi-layer can work on the visible light of a large wavelength range, reducing

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