Appearance: milky white dispersed liquid
Particle size: 4-20
Solubility: can be evenly dispersed in water-based paints, coatings and other dispersion systems
Stability: stable under storage conditions below 40℃
The development of inorganic antibacterial agents
In addition to the organic antibacterial agents described above, there is also a class of inorganic antibacterial agents, which are also beginning to be used in coatings. It has a wide antibacterial spectrum, a long antibacterial period, low toxicity, no drug resistance, and good heat resistance.
Inorganic antibacterial agents are a class of antibacterial agents prepared by using the sterilization or antibacterial ability of metals such as silver, copper, zinc, titanium and their ions. The most striking is the inorganic metal ion type antibacterial and antifungal agent. People have successively selected zeolite, polypropylene wax wollastonite, ceramics, insoluble phosphate and other substances with strong chemical binding force to metal ions as carriers, and loaded silver ions to prepare antibacterial agents [10,
In the coating industry, the common inorganic metal oxide antibacterial agents are nano-ZnO and nano-TiO 2. Nano ZnO and nano TiO 2 are a kind of photocatalytic inorganic antibacterial agent.
People have long known that ZnO has anti-mildew function, but it is necessary to prevent the gelation problem of ZnO paint [30.31]. ZnO powder has certain antibacterial properties, but its antibacterial properties are weak, and it is rarely used as an antibacterial agent alone. The compound of four-pin ZnO whisker and nano-ZnO has good antibacterial properties and can be used as an antibacterial agent. Its minimum inhibitory concentration (MIC) is 150~300mg/kg, and its LDso is greater than 10000mg/kg, which is a non-toxic product D ,
Nano-Ti Oz photocatalytic inorganic antibacterial agents generally use anatase Ti Oz. It has good antibacterial, air purification and organic degradation effects. The principle is: Anatase Ti Oz is a semiconductor material with a band gap of 3.2 eV. Only photons greater than 3.2 eV, that is, ultraviolet light with a wavelength less than 388 nm, can excite electrons in the valence band to the conduction band. The conduction band forms negatively charged highly active electrons and generates positively charged holes in the valence band. Highly active electrons can oxidize OH- and Hz O molecules adsorbed on the surface of TiO to form hydroxyl radicals HO·, while O adsorbed or dissolved on the surface of TiO 2 is easily trapped by positively charged holes to form ·O. . The oxidation energy of HO·and·O is above 500kJ/mol, which is why the antibacterial agent has good antibacterial properties, purifies the air and degrades organic matter [14.32.33],
However, the use of nano-Ti Oz photocatalytic inorganic antibacterial agents in coatings still has the following problems to be solved.
①HO·and·O, while antibacterial, purifying the air and degrading harmful organics, they also degrade coating components, including resins and pigments, which involves the choice of resin and how to solve the problem of color matching.
②There is almost no ultraviolet light in cloudy, rainy, indoor and at night, and its antibacterial, air purification and organic degradation performance are greatly affected. Doping is now being used to reduce the excitation energy so that it can use visible light.
③The dispersion and stability of nano-TiO 2 are maintained.
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