| Polyvinyl chloride [poly (vinyl chloride), PVC] has high mechanical strength,corrosive, low prices, flame retardancy and electrical insulation, mainly uesd fortransparent cable, soft toys, medical equipment, food packaging film, artificial leatherproducts, and plank, doors and Windows, piping and valves and other hard products,ithas become the second largest uesd after polyethylene resin.But PVC has unstable chlorine atom in the chain, which began to decomposeHCl at100℃, the conjugate polyenoid structure which can color development beformation immediately on the molecular chain, products change color. because theHCl can catalytic the process of PVC degradation, with the rise of temperature orheated time, HCl be accumulated in the material,which is very easy to cause“zipperdehydrochlorination†greatly accelerated the degradation of PVC, makes thematerial color deepened sharply, the drop of physical and mechanical properties,even carbonized to lost use value. So heat stabilizers must be used in PVC products.In this paper,we discussed the PVC thermal degradation mechanism at first, andclarified the development of the PVC heat stabilizers at present. The TraditionalPVC’s thermal stabilizer contains heavy metals such as lead, cadmium, along with thestrengthening of environmental protection consciousness, such heat stabilizersl will beexit in the stage of history; Organotin heat stabilizer has excellent thermal stability,but the price is expensive, which limited the use of promotion; but calcium/zinc soapseries heat stabilizers is considered nontoxic plastic additives in the world, it hasbecome the research hotspot. And the liquid zinc/calcium heat stabilizers have beenapplied more and more because of environmental protection, easy to measure, lowprices, production and application process no dust pollution.This paper mainly ues organic acid and calcium/zinc oxide as the material, synthesisof organic acid calcium soap and zinc soap, and discusses the the ratio, synthesistemperature and synthesis time on the influence of the metal soap by titrating the freeacid and calcium, zinc percentage content, get the best synthetic technology for liquidmetal soap, and using the infrared spectral measur the synthetic products.The Congo red method, thermal aging oven method, the dynamic roller pressure,take off HCl experiment and thermogravimetric analysis examines the zinc, calciumsoap quality than epoxy soybean oil and the quality of phosphate ester than andorganic ketone, polyols, antioxidants and the amount of the thermal stability of PVCinfluence on the performance of the. And for the first time, inorganic auxiliary heatstabilizers-water talc (LDHs) into transparent, soft PVC, and the thermal stabilitymechanism is discussed. the coordination effect has been examine between some ofthe heat stabilizers, we get the best liquid calcium/zinc heat stabilizers through theblending.2.5phr the best formula stabilizer add in PVC, the sample can keep stability at180℃in65min. It’s thermal stability properties excellent than the similar productsin the market. At the same time, we test the performance according to the nationalstandard《Plasticized polyvinyl chloride(PVC)compounds for wire and cable》,the test results reach to the basic standards... |
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