High density polyethylene
High density polyethylene (HDPE) is formed by polymerizing ethylene under low pressure using Ziegler catalysts and metal oxide simplifying agents, hence also known as low-pressure polyethylene. The density is between 0.940 and 0.965g/cm3.
Performance characteristics
High density polyethylene is a white powder or granular product, non-toxic, leafless, with a crystallinity of 80%~90%, a softening point of 125~135 ℃, and a usage temperature of up to 100 ℃. Its hardness, tensile strength, and creep resistance are superior to those of low-density polyethylene; Wear resistance, electrical insulation, toughness, and cold resistance are better, but slightly worse than low-density polyethylene; Good chemical stability, insoluble in any organic solvent at room temperature, resistant to corrosion by acids, alkalis, and various salts; The film has low permeability to water vapor and air, and low water absorption; The aging resistance is poor, and the environmental stress cracking resistance is not as good as low-density polyethylene. Especially, thermal oxidation can cause its performance to decline. Therefore, antioxidants and UV absorbers need to be added to the resin to improve this deficiency. Attention should be paid to the fact that high-density polyethylene film has a lower thermal deformation temperature under stress when applied.
quality standard
The quality index requirements for high-density polyethylene resin are specified in the standard GB 11116-89.
Forming methods and applications
High density polyethylene resin can be used to form plastic products through injection, extrusion, blow molding, and rotational molding methods.
Injection molding machines can be used to inject various types of daily necessities, containers, industrial accessories, medical supplies, toys, shells, bottle stoppers, and covers.
By using blow molding method, various hollow containers, ultra-thin films, etc. can be formed.
Using an extruder to extrude pipes, stretching strips, bundling straps, monofilaments, wires, and cable sheaths.
In addition, it can also form decorative panels, blinds, synthetic wood, synthetic paper, synthetic films, and molded calcium plastic products for construction.
