The PVC monomer arises from the reaction between ethyne and hydrochloric acid, and the monomer thereafter is aggregated into PVC through various methods, PVC is devoid of stability against heat and light, and therefore, stabilizers shall be added therein to avoid discoloration or decomposition upon the materials’ being processed into finished products. Various stabilizers are available, including metal soap and organic tin compounds and they fall into such types as transparent, opaque, soft and hard ones. The processing temperature of soft PVC is 70—100 celsius degree. Hard PVC requires less time for processing, yet the temperature therewith must rise to approximately 150 celsius degree. Due to it’s low fluidity during fusion, hard PVC tends to be more difficult to be injected and molded than polystyrene(PS). However, even without intensifier, hard PVC still boasts a pretty high mechanical intensity, it is also sound in electric insulation, acid resistance, alkali resistance as well as water resistance; moreover, it is transparent and can be colored freely and processed effectively. Soft PVC is endowed with sound plasticity and hence is inferior to hard PVC in the aforementioned properties, yet it can be made into soft membranes or thin plates. The softening temperature whereof is approximately 80 celsius degree and the decomposition temperature is around 273 celsius degree.
PVC, with such shortcoming as weak heat resistance capacity, will soften promptly under the temperature of 65—80celsius degree and can decompose easily under high temperature.
PVC can be used to make tablecloth, packing membranes, vehicle curtains, briefcases, handbags and chemical shoes etc, it’s glue film can absorb ultraviolet radiation and therefore embodies sound thermal insulation property. Hard PVC can be applied to such fields as watercourse piping, chemical plant piping, building materials, signboards, telephones, electric parts as well we drug-proof apparatus etc.