Weathering Improvement And Study On HALS

Hindered amine light stabilizer is in the mid- 1970- a new type of high efficiency light stabilizer, it is mainly used for polymer materials such as plastic, rubber aging proof.Hindered amine light stabilizer under aerobic condition, absorbing sunlight and nitrogen oxygen free radical formation, the nitrogen oxygen free radicals can not only capture a polymer material light oxidation on alkyl activity of free radicals, and in the process of oxidation of light can be regeneration function, thus inhibiting chain reaction to achieve protection. Since the 1990 s, the people were found not only has good effect on anti ultraviolet light, also have good advantages on thermal oxidation. Usually by the extruder with polypropylene blends, add antioxidants and achieve the synergy of uv and antioxidant. However in the premixed with polypropylene matrix after extrusion, hindered amine light stabilizer of piperidine alcohol heat will melt and become easy to precipitate agglomerate, especially in some tropical regions of the high temperature. Piperidine alcohol can through fatty acids and fatty acids in plants, animals but because most countries for the protection of animals, so would prefer to use plant fatty acids. And made of plant fatty acid piperidine alcohol than animal fats piperidine alcohol lower melting point, usually at 25 degrees Celsius, so use in tropical heat region often causes precipitation of particles and agglomeration, create extremely inconvenient to use charging. So you need weatherability of hindered amine light stabilizer modification to meet under different conditions of use and ensure the quality.In this thesis, by adding 1% and 2% respectively doses of gas phase silica and precipitated silica modification of hindered amine light stabilizer. Repass determines if add effective precipitation, caking experiment, DSC differential scanning calorimetric determine a change in hindered amine melting point, ir analysis the change of main composition, melt index test for determining added silica hindered amine light stabilizer is molten liquid has the damage, and then through the xenon lamp weathering exposure experiments to determine whether adding silica will have an impact on product application.Through four groups of different doses of different additives, has proved its resistance to precipitate the caking property is greatly enhanced, at the same time, melt index, index of important applications such as xenon lamp exposure exposure there is no change. The reason for the silica itself for porous superfine powder, the superfine will give product surface formation porosity more protective layer, after the waxy piperidine alcohol precipitation material, to fully adsorption, among the active ingredients in the product. Silica and very lazy at the same time, will not have negative impact to the product performance. Finally, four groups of experiments show that the gas phase silica added 2% of the volume effect is most obvious, effectively by adding 2% of the gas phase silica, weatherability of hindered amine light stabilizer can substantially increase, can fully against 40-50 degrees centigrade high temperature climate, offer the convenience of product applications in the tropics.