Study On Non-toxic Liquid Composite Heat Stabilizers

As a widely used poly (vinyl chloride), the demand of stabilizers, which resist degradation of PVC, is increasing correspondingly. Ca / Zn stabilizers are generally recognized as non-toxic additives of plastic products, which have been widely used in flexible poly ( vinyl chloride). This paper have been discussed the synthesis of calcium or zinc isooctanate and lanthanum monoisooctyl maleate, and compounding of different heat stabilizers, aim to investgate a non– toxic liquid Ca / Zn isooctanate composite stabilizer. Effect of the best ratio of calcium to zinc, additives and so on has been discussed, and synergism of composite stabilizer has been further studied.Isooctanoic acid, calcium oxide and zinc oxide as materials, calcium isooctanate, zinc isooctanate were synthesized, respectively. The optimum synthetic condition of calcium isooctanate and zinc isooctanate were stated as follows: m(isooctanoic acid)∶m(calcium oxide) = 1.7∶1, reaction time 2 h, reaction temperature 70~80℃, the dosage of mineral is 70 % of isooctanoic acid weight; m(isooctanoic acid)∶m(zinc oxide) = 1∶1.05, reaction time 2 h, reaction temperature 70~80℃, the dosage of mineral is 25 % of isooctanoic acid weight.The lanthanum monoisooctyl maleates were synthesized from maleic anhydride, 2-ethylyexanol and lanthanum hydroxide in two steps, the optimum synthetic condition of which shows during the first stage: n(maleic anhydride)∶n(2-ethylyexanol) = 1.05∶1, the catalysts were in excess of 4‰, reaction time 2.5 h, reaction tempeture 90℃; In the second stage, the optimum synthetic condition of maleic anhydride and lanthanum hyoxide which shows: n(monoisooctyl maleate)∶n(lanthanum hydroxide) =3∶1.05, reaction time 2 h, reaction temperature 90℃.The thermal stability of liquid Ca / Zn composite heat stabilizers was investigated by Congo red method , Ageing oven method, Conductivity method and Thermogravimetry, calcium to zinc ratio,β-diketone, polyols and antioxidant were conducted to discuss the effect on which, and synergistic effect of epoxidized soybean oil and phosphite was studied. Nowadays, SPJ-501 and SPJ-502 stabilizers are in pilot-testing scale, whose the stability time, mechanical properties and processing properties are superior to that of similar products in the market. The LD50 of stabilizers is more than 5 000mg·kg-1 and is basically innocuous.The 50 ton stabilizers have been put into production, which have been applied in gymnastic balls and transparent films, and have no bubble nor precipitation, which show excellent thermal stability.