1. The relationship between toughness and flame retardancy of PE
Ordinary PE toughness is very good, better than PVC pipe. But the concept that everybody comes out is to be based on common PE tubing character.
For coal mine pipe sources, flame retardant and antistatic.
For antistatic PVC or PE, the insulation is good, the surface resistivity of up to 1012-15 Ω, need antistatic agent to reduce to 1 * 106 Ω surface resistance, the amount and type of adding antistatic agent is not in the difference. However, PVC itself is flame retardant, it can easily meet the flame retardant standards set by mt-181, and PE is flammable material, need to add a lot of flame retardant agent to meet the flame retardant standards of mt-181, its impact resistance will decline lower than PVC pipe. Therefore, at present, some mine PE pipe can not meet the flame retardant standard, is this reason, no or less with flame retardant, reduce the manufacturing cost, but also avoid the tube too brittle phenomenon.
PE raw material manufacturing, in the world at present only one channel, is the use of petroleum in the mouth of light oil such as naphtha cracking, produce ethylene, ethylene polymerization, produce different brands, different specifications of polyethylene. Therefore, its price is closely related to the international crude oil price.
To make the coal mine use PE pipe, need to add antistatic masterbatch and flame retardant masterbatch, masterbatch, is to add a certain amount of antistatic agent in PE raw material or flame retardant, or both, mixed granulation, again after masterbatch and at present very little pipe factory can produce masterbatch, because masterbatch production technical, many of them are patent or proprietary technology, are generally pipe factory purchased from masterbatch manufacturer or dealer. The price of masterbatch is PE price adds 5000 yuan of the left and right side again commonly, for example PE14500 yuan/catty, masterbatch is about 19500 yuan/catty, the addition of masterbatch sees masterbatch in effective component, how many and performance are concerned, it is 30-45 or so commonly. Now suppose the raw material price of PE100 is 15,000 yuan/kg, the masterbatch is 20,000 yuan/kg, and the number of masterbatches added is 30. Then in 1000 kg of PE, 300 kg of masterbatch is added, and the total price is 15,000 +20000 30% = 21000 yuan. The total weight is 1300kg, which is equivalent to 16,153 yuan per ton, plus the processing fee of 2,000 yuan per ton (electricity fee). The cost of each ton of pipe is 18,153 yuan per ton. Not counting the production plant staff wages, equipment depreciation, marketing costs and other costs.
At present, the sales price of some PE pipes is very low, lower than the price of the above raw materials and electricity, the only possibility is to use the low price of non-pe100 raw materials.
The price of PVC is much lower than PE. For example, at present, PE is about 14,000 yuan per ton, while PVC is only about 6,500 yuan. Of course, PVC is still added with expensive stabilizers and toughening agents, but the overall price of raw materials is much lower than PE.