The material properties of plastic pipe production lines are an important basis for quality assurance. The molecular weight of the resin and its distribution range have a great influence on the performance of the product. The lower the molecular weight, the wider the distribution range, and the greater the MI (melt flow rate). The compression density is high. The service life of shear plasticization is shortened as the strength of the pipe decreases, and it is more likely to have many quality problems such as pipe rupture and rapid aging.
Therefore, well-known domestic floor heating companies generally use high-quality imported PE-Xa special resins such as XL1800 and 8100X, and the MI (190℃, 21.6kg) is about 2g/10mm.
The price of making PE-Xa pipes with domestic LLDPE7042 is cheap, but the MI is too large, the molecular weight is low, and the density is low, resulting in low strength, fast aging, and short service life. Therefore, it is easy to burst. After use, the pipe is cut by rework, so reconnection cannot be avoided.
The resin has high volatile components, and small holes are opened on the surface or hidden places of the pipe. The degree of stress concentration is different, which affects the high temperature resistance of the product and shortens its service life.
Therefore, in addition to the volatile substance certification of the resin processing enterprise, the plastic pipe production line will not be damp or polluted by water during transportation and storage.
At the same time, attention should be paid to the order and skills of supply to ensure the time and uniformity of raw material mixing, which is generally controlled within 15 minutes to make the resin and various additives dispersed evenly. Ensure stable product performance and long service life.
The amount of cross-linking agent added should be accurate, and the degree of cross-linking should reach a certain height, which can not only meet the standard requirements, but also ensure the stability of the quality of the cross-linking agent.
If the performance of the cross-linking agent is poor, it only needs to be added in large quantities to ensure the degree of cross-linking. The residual monomers after cross-linking will affect the performance and service life of the product. Therefore, good domestic floor heating companies generally insist on using expensive but high-quality plastic pipe production line jointing agents.
Cross-linking is the process of generating free radicals. In order to capture residual free radicals and eliminate unstable atoms after cross-linking is completed, additional primary and secondary antioxidants are added to control thermal aging, also in the pipes during use. It can effectively prevent exposure to high temperatures. Under aging and oxidation, the performance of the material slowly decreases, and the service life can be extended.