background and overview[1]
uv absorber uv-326 is a benzotriazole light stabilizer, 2′-(2′-hydroxy-3′-tert-butyl-5′-methylphenyl)-5-chlorobenzotriazole azole. uv-326 can absorb ultraviolet light of 280-370nm. it has good stability, low toxicity and no irritation to the human body. it is widely used in coatings, synthetic rubber, synthetic fibers, photosensitive materials, etc. it can effectively improve the light resistance of these materials and reduce the risk of yellowing, aging and other phenomena caused by ultraviolet stimulation in sunlight.
preparation[1]
diazotization reaction: weigh 6g of 98wt% h2so4, 50ml of water and 0.03mol of p-chloro-o-nitroaniline into the reaction kettle and cool to 5 ℃, slowly add 15g of 20wt% nano2 solution dropwise, and continue stirring for 1 hour until the reaction is completed. add urea to decompose the remaining nitrous acid, and filter to remove residue.
coupling reaction: weigh 0.03mol 2-tert-butyl-p-cresol, 50ml water, and 0.1g sodium dodecylbenzene sulfonate into the reaction kettle, and stir to form a uniform white emulsion. adjust the ph to 7-9, and add the above diazonium salt solution dropwise within 2 hours under this weakly alkaline condition. after the reaction, filter, wash, dry and weigh.
glucose reduction reaction: weigh 0.015 mol of the product obtained from the diazo coupling reaction and 10 g of naoh solution
add (20wt%) into the reaction kettle, and when the temperature reaches 50°c, slowly add 100ml of 30wt% glucose solution dropwise, continue the reaction for 1 hour, filter and drain after cooling, and obtain the nitrogen oxide intermediate.
zinc powder reduction reaction: add 17ml of chlorobenzene and 42g of 14wt% h2so4 to the above nitrogen oxides, and heat to 90°c. add 1.1g zinc powder in batches within 2 hours, add activated carbon after the reaction, stir for 0.5 hours, filter while hot, separate the filtrate into layers, wash the oil layer with water until neutral, and evaporate the solvent to obtain the target product. the analysis results showed that the product yield reached 90.9% and the purity reached 99.3%.
apply[2]
a high-strength environmentally friendly polyvinyl chloride pipe. its components are proportioned by mass percentage: polyvinyl chloride 45%, glass fiber 12%, wollastonite 10%, di(2-ethyl phthalate) methyl hexyl ester) 9%, methacrylate-acrylate copolymer 8%, melamine cyanurate 9%, antistatic agent hkd-912 2%, ultraviolet absorber uv-326 2%, calcium zinc stabilizer 1.5%, pe wax 1%, antioxidant 1010 0.5%, the glass fiber is an alkali-free glass fiber with a surface treated by a silane coupling agent, a diameter of 4 to 18 μm, a length of 3 to 6 mm, and an aspect ratio of 7 to 9. the wollastonite is a fibrous wollastonite whose surface has been modified by a silane coupling agent and has a diameter of 6 to 25 μm, a length of 10 to 500 μm, and an aspect ratio in the range of 3 to 100.
preparation method: (1), weigh each component according to weight ratio; (2), add polyvinyl chloride, di(2-ethylhexyl phthalate) and calcium zinc stabilizer into the barrel in a mixer with a temperature of 80°c to 90°c, mix at a speed of 50 to 80r//min for 20 to 30 minutes, then add other components, and continue to stir for 20 to 40 minutes. after the mixture is evenly mixed, discharge the material; (3), the mixture obtained in step (2) is added to a twin-screw extruder for mixing and then extruded to form a pipe, thereby obtaining the high-strength environmentally friendly polyvinyl chloride pipe.
references
[1] [invented in china] cn201711146740.6 synthesis method of ultraviolet absorber uv-326
[2] [invented in china] cn201410847488.1 a high-strength environmentally friendly polyvinyl chloride pipe and its preparation method