Study On Preparation And Properties Of Liquid Composite Thermal Stabilizers Of PVC

Polyvinyl chloride(PVC)has been widely used due to its low cost,flame retardant,resistance to chemical corrosion,and good insulation.The PVC has good transparency.So it is suitable as the material for the transparent film,transparent soft plate,etc.But the usability and transparency of PVC are very easily damaged by the degrading in the processing.So the industry of the heat stabilizers matched with the PVC is becoming more and more important with the development of PVC industry.At present,the common heat stabilizers are lead salt,metal soap,terres rares,organic tin and so on.Ca-Zn composite heat stabilizers attract a lot of attention due to environment-friendly,good transparency and good lubricity.The four kinds of metal salt which were zinc/calcium/magnesium/sodium isooctanoate were synthesized by one-step which isocaprylic acid,zinc oxide,calcium hydroxide,magnesium hydroxide and sodium hydroxide were used as raw materials,white oil used as solvent and diethylene glycol butyl ether as the reaction promoter.At the same time,epoxidized oleic acid was synthesized with Oleic acid,peroxide and formic acid.Epoxidized zinc(calcium,barium)oleate were synthesized by double decomposition reaction.The isooctanoate metallic salts and epoxidized oleate metallic were used in PVC composite system.And the effects of quality ratio of metal ions on their thermal stability,processability,thermal aging and HCl release rate were characterized by Congo red method,HAAKE torque rheometer,thermal aging oven method and conductivity method.The experimental results showed that:the static thermal stability time of the ternary compound system was longer than binary compound system.It had the best thermal stability when the quality ratio of metal ions of sodium/calcium/zinc isooctanoate was 1/3/2 and the quality ratio of metal ions of magnesium/calcium/zinc isooctanoate was 3/1/2 in the ternary compound system.And it also had the best thermal stability when the ratio of epoxidized calcium oleate/epoxidized barium oleate/epoxidized zinc oleate was 1/3/1.The thermal stability and transparency of the PVC systems were studied which was added with different quality proportion of the hydrotalcite and the best mixtures above mentioned,respectively(the ratio of sodium/calcium/zinc isooctanoate was 1/3/2 and the ratio of calcium/barium/zinc oleate was 1/3/1).The results showed that the thermal stability of sodium/calcium/zinc isooctanoate system could be markedly improved by filling with hydrotalcite.And the addition of hydrotalcite could also improve the the static stability time and of epoxidized calcium/barium/zinc oleate system to a certain extent.