Composition: Amino silane
Appearance: colorless to light yellow transparent liquid
Active substance content: 50%
Among the aromatic esters, salicylic acid is a universal aromatic ultraviolet absorber. It has a high absorption coefficient for ultraviolet rays with wavelengths below 340nm. After light absorption, the molecules rearrange into a benzophenone structure, and the absorption range is significantly increased. ; The disadvantage is that due to the absorption of visible light, there is a yellowing tendency.
Oxalanilide compounds absorb short-wave ultraviolet light with a wavelength of 280~320nm, and form intramolecular hydrogen bonds to convert excited state energy. At the same time, they have the functions of antioxidants and metal ion passivators. The triazine compound absorbs ultraviolet rays with wavelengths of 280-380nm, broadly absorbs ultraviolet rays, has a large number of ortho hydroxyl groups, and absorbs strong ultraviolet rays. Different substituents on the benzene ring improve its chemical resistance, light resistance and compatibility. Formamidine compounds have strong absorption in the short-ultraviolet region of 290-320nm wavelength, and their absorption coefficient is 30% higher than that of benzhydryls. They are excellent absorbers for short-wave ultraviolet-sensitive film-forming materials.
The varieties currently used in powder coatings include Hubei Hongtu Chemical Products Co., Ltd.’s ultraviolet absorber UVF, which is white to slightly yellow crystalline powder, content ≥99%, melting point 128~132°C, relative density 1.26, and the dosage is the total formula 0.1%~0.5% of the powder, dispersed by melt-extrusion mixing method. The ultraviolet absorbers AS801 and AS810 of Guangdong Tianlong Chemical Co., Ltd. polytetrafluoroethylene (ptfe) powder can absorb a large amount of ultraviolet light and convert it into harmless low-energy radiation.
The gas-bonded compound ring formed in the molecule absorbs light quantum and converts the radiant energy into heat. Avoid the damaging effect of ultraviolet rays, enhance the weather resistance, color retention and vividness of the coating film. The dosage is 0.2% to 0.5% of the total formula, and it is dispersed by the melt extrusion mixing method. The UV absorber DC-1595 of Dongguan Dachang Chemical Auxiliary Co., Ltd., the dosage is 0.4%~0.8% of the total formula; the UV absorber DC-1078, the dosage is 0.1%~1% of the total formula; UV absorber DC -2061, the dosage is 0.4%~1% of the total formula; UV absorber DC-1506, the dosage is 0.5%~1% of the total formula, all are dispersed by melt extrusion mixing method. In addition, Ciba, etc. also have many varieties of ultraviolet absorbers, such as UV-531, UV-327 and so on. The test results show that the addition of ultraviolet absorbers can significantly improve the weather resistance, gloss retention and color retention of the coating film. However, some varieties have poor compatibility with the film-forming material and poor dispersion. Bring some negative effects on the appearance of the coating film.
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