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In recent years, some problems of the old generation of polyolefins have been solved with the introduction of double-peak PE100 and PE80 materials. One of the basic problems of the previous generation polyolefins was the problem of sagging in the pipe production process. In the pipe production process, pipe cooling is done from the outer wall, which means that the newly formed pipe, after leaving the extruder die, is in contact with the cooling currents only from the outside surface, and its inner surface remains molten for some time. stayed The thicker the pipe wall, the longer this time will be. In this way, the molten materials on the inner surface of the tube will have the opportunity to flow down under the force of gravity and cause the unevenness of the wall thickness and the roughness of the inner surface of the tube. By changing the material from 80MRS to MRS100, the thickness of the pipe is reduced, and as a result, the inner surface cools down faster, and this problem is solved to some extent.

(Low Sagging or LS).

What polyolefins producers can do to fix the viscosity of the material is to change the viscosity of the polymer. As mentioned, melt viscosity of most polymers decreases with increasing shear stress. If we pay attention to the melt flow curve of common types of polyethylene, it can be seen that the viscosity increases as the shear rate decreases, but in the range of low shears, the curve becomes almost linear and with a further decrease in the shear rate, the viscosity will not increase significantly. Adding a percentage of polymer chain with a very high molecular weight to the material (bipolar distribution) causes the viscosity to continue to increase even at low shear rate, and at zero shear (the state that occurs in the slitting tube) the viscosity of polyethylene is higher and As a result, the amount of leaching is less.

By means of polyolefins with double distribution, it is possible to produce larger pipes with more wall thickness without changing the process conditions. The record obtained with these materials is a pipe with a diameter of 1600 mm and a wall thickness of 100 mm.

• Polyethylene pipes and fittings are resistant to chemicals and do not suffer from corrosion. For this reason, in projects where metal or concrete pipes and fittings suffer from rotting and corrosion, polyethylene pipes and fittings stand out with strength.
• Polyethylene joints have the same resistance as the main pipe, and in case of standard welding, the piping system will be completely uniform.
• Polyethylene pipes are flexible and therefore these pipes can be resistant to earth movements and earthquakes and can withstand severe stresses easily. This feature greatly reduces the cost of repairs or reconstruction of transmission lines.
• Polyethylene materials with products in pressures between 2 to 25 bar and even more and in sizes from 20 mm to 2000 mm and even more can meet all the needs of an industrial project.
• Polyethylene pipes, fittings and manholes have a much lower cost of chipping and bedding than their metal or concrete counterparts, and even in some projects, it does not require bedding.
• Polyethylene products, including polyethylene pipes, polyethylene fittings and polyethylene manholes, have a very long service life (over 50 years).
• Polyethylene pipes, fittings and manholes are resistant to biological attacks, therefore it can be used to transport urban drinking water and it does not need to process the pipe to transport drinking water, which can reduce implementation costs by 50%. .
• Polyethylene pipes, fittings and manholes have a light weight, which makes the transportation of these equipments easier than metal and concrete samples, and reduces implementation costs and a higher speed of transfer from the place of production to implementation.
• Polyethylene pipes, connections and manholes are environmentally friendly and waste less energy due to the lack of insulation, and less greenhouse gases are produced in their production. In addition, due to the possibility of returning polyethylene pipes and fittings to nature, they do not cause environmental pollution and can be converted into energy again after the end of their service life.
• Polyethylene raw material allows to achieve better functions by changing it and it is possible to convert it into products with higher efficiency.

(quoted from Pars Ethylene Kish website)

Applications of polyethylene pipe and polyethylene fittings

– Municipal and industrial sewage
-Cable covering of oil product transmission lines
– Fluid lines in factory processes
– Cold water lines for industrial units (refineries, petrochemical factories and power plants)
– Fire extinguishing networks
– Main high pressure lines
– Industrial sewage lines
– Water distribution network
– Water transmission lines with high hardness and sea water transmission
– High pressure water injection lines
– Air conditioning lines (HVAC)

-Gas supply