The flame retardany influence of Calcium carbonate filler

       Calcium carbonate`s thermal decomposition temperature is above 800 ℃, but the general plastics are flammable, and the ignition temperature is about 400 ℃. So the hope of calcium carbonate decomposition may release carbon dioxide is impossible in the initial stage. The advantages of calcium carbonate is only to reduce the amount of combustible, and the higher the content of calcium carbonate, the less combustible in the same volume, which is benefit to antiflaming. But due to the presence of calcium carbonate, numerous pores are formed in the process of the rapid expansion and gasification combustion, which greatly increase the surface area of the fuel and oxygen contact, and further raise the temperature of fire area, more conducive to the expansion of the fuel and gasification. So the contribution of non-combustible material is so insignificant. In the 1990s, Japan and other countries added 30% of the heavy calcium carbinate in polyethylene bags, which was considered for the help flaming of calcium carbonate in PE in the incinerator.

         Experiments show that the combustion time of polyethylene films containing 30% calcium carbonate and 1% antioxide was only 4 sec, but the time of pure polyethylene film was 12 sec.