Calcium and zinc composite stabilizer is composed of organic acid salts of calcium and zinc,and organic auxiliary heat stabilizer such as phosphite ester and solvent.Because it does not contain cadmium,lead,barium and other toxic heavy metals,it is considered as an environmental stabilizer and widely used as a pvc heat stabilizer in the processing of PVC products.However,under normal conditions,most calcium zinc composite stabilizers have not been approved by FDA and other authoritative health agencies for food packaging and medical materials(mainly the selection of small molecule phosphite ester,fatty acid,etc.,are not approved by FDA),so it is necessary to pay attention to identify its health grade when choosing calcium zinc composite stabilizers.
　　The main components of calcium and zinc compound stabilizer include:organic acid salts of calcium and zinc,solvents and organic auxiliary heat stabilizer,their specific characteristics are as follows:
　　1)The organic acid salts of calcium and zinc are the products of the reaction of various organic acids with calcium hydroxide and zinc oxide.The commonly used organic acids include isocaprylic acid,isocapric acid,oleic acid,naphthenic acid,benzoic acid and p-tert-butylbenzoic acid.Generally speaking,the organic acids selected as liquid thermal stabilizers are branched or unsaturated fatty acids and aromatic acids.Saturated straight chain fatty acids are not suitable for the production of liquid thermal stabilizers but for the production of solid stabilizers.
　　2)The selection of solvents should follow the principle of similarity and compatibility.If the main stabilizer is fatty acid salt,it is better to choose aliphatic solvent;If the main stabilizer is aromatic acid,it is better to choose aromatic solvent.If the metal content is high,the solvent needs to be selected to prevent delamination during storage of the liquid stabilizer.Solvents are chosen for their appearance,smell and volatility,as well as cost.