Two key points in the production process of blow molding geomembrane
By selecting the blow molding method, a smooth geomembrane can be made, or a rough geomembrane can be made, and the composite geomembrane has different materials and different functions, such as a surface smoothing general smooth geomembrane, and the middle layer is a foam layer thermal insulating geomembrane. The middle layer is a cheap layer economic geomembrane. A large number of smooth geomembranes are now produced.
The geomembrane blowing process has two key points, one is the selection of raw materials and formulation design, and the other is the control of process conditions. Blowing geomembrane material selection and formulation design I blow molding geomembrane material selection: blow molding legal geomembrane, the general equipment is relatively large, it is difficult to clean. Therefore, for a heat sensitive resin such as PVC, it is not suitable to produce a geomembrane by a blow molding method. If the melt strength of the polymer is too low, it will be difficult to form a lead film. Even with occasional success, because of the frequent breaks in the film, it creates great difficulties for stable production.
Therefore, for linear low-density polyethylene, metallocene linear low-density polyethylene and the like have low melt strength and are generally not directly used for the blow molding of geomembrane. Because linear low density polyethylene metallocene linear low density polyethylene, excellent mechanical properties, especially tensile strength of metallocene linear low density polyethylene can be as high as 50 ~ 60 mpa, usually more than 2 times sports, they are with ordinary PE And good compatibility, therefore, generally use low-density polyethylene, high-density polyethylene mixture, progress in general tensile strength of PE, high-density polyethylene softness and so on. The preparation of multi-layer composite geomembrane on a common extruder can improve the mechanical properties of the polyethylene geomembrane.
From the perspective of geomembrane production, low density polyethylene, medium density polyethylene, high density polyethylene, polybutylene, and EVA are suitable for the production of geomembranes by blow molding. The method of blowing the geomembrane is designed to produce the geomembrane by blowing, and the polymer is melted and plasticized at a high temperature of 180-230 ° C. Therefore, the polymer to be used must have heat resistance to ensure that under such high temperature conditions. , within a certain period of time, or little degradation. In the process of storage, transportation and construction, geotechnical work cannot avoid contact with sunlight and oxygen in the air. The general polymer is very resistant to oxygen and ultraviolet rays. Therefore, the formulation of geomembrane is very important in the process of making geomembrane, and it is also a very complicated problem.
