High density polyethylene
DATE：2022/12/17 8:32:56 / READ： / SOURCE：This station
2.1.2 High density polyethylene
High density polyethylene is a white powder or granular product, non-toxic, leafless, with crystallinity of 80%~90%, softening point of 125~135 ℃, service temperature of 100 ℃, and hardness, tensile strength and creep better than low-density polyethylene; Wear resistance, electrical insulation, toughness and cold resistance are good, but slightly worse than that of low-density polyethylene; Good chemical stability, insoluble in any organic solvent at room temperature, and resistant to acid, alkali and various salts; The membrane 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 that of low-density polyethylene. Especially, the thermal oxidation will degrade its performance. Therefore, antioxidants and ultraviolet absorbers should be added to the resin to improve this deficiency. Attention should be paid to the low thermal deformation temperature of high-density polyethylene film under stress. See Table 2-1 for performance parameters of high-density polyethylene.
See Table 2-5 for the comparison between the new standard resin brand and the original brand.
The new brand is described as follows.
The grade is divided into 4 units. Abbreviation code PE of polyethylene shall be marked in unit 1. The main use or processing method of polyethylene (listed in the first place in Unit 2), the importance of resin, additives, color and state (granular or powdery) [listed in the second place to the fifth place] shall be marked in Unit 2. The colorless and granular resin need not be listed. Mark according to the codes in Table 2-6. The resin density and melt flow rate marked in Unit 3 are only test conditions. The density value is represented by two numbers (see Table 2-7), followed by a letter and three numbers representing the melt flow rate value and test conditions (marked according to the codes in Table 2-8 and Table 2-9). The type of filler or reinforcement material shall be marked in Unit 4, which shall be written in the first digit of a letter code; Its physical state is written with another letter as the second digit of the code (see Table 2-10 Code); The mass fraction is coded with two digits and is written in the third digit (according to the code in Table 2-11).
The injection molding machine can be used to inject various types of daily necessities, containers, industrial accessories, medical supplies, toys, shells, bottle stoppers, shields and other products.
The blow molding method can be used to form various hollow containers, ultra-thin films, etc.
Extruder is used to extrude and shape pipes, tensile strips, binding tapes, monofilament, wire and cable sheaths, etc.
In addition, it can also be used to form architectural decorative panels, shutters, synthetic wood, synthetic paper, synthetic films and molded calcium plastic products.
Refer to Table 2-12 for products with different melt flow rates recommended for molding in high-density polyethylene resin.
PE-JA50D012 grade or GB/T13,849-93 standard shall be used for extrusion molding of high-density polyethylene resin for insulated cables. See Table 2-13 for required parameter values of various indicators
When selecting HDPE resin for application, attention should also be paid to the influence of different densities on the properties of polyethylene (see Table 2-14).
High density polyethylene (HDPE) is made by polymerization of ethylene under low pressure with Ziegler catalyst and metal oxide reductant, so it is also called low pressure polyethylene. The density is 0.940~0.965g/cm3.
2.1.2.1 Performance characteristics
High density polyethylene is a white powder or granular product, non-toxic, leafless, with crystallinity of 80%~90%, softening point of 125~135 ℃, service temperature of 100 ℃, and hardness, tensile strength and creep better than low-density polyethylene; Wear resistance, electrical insulation, toughness and cold resistance are good, but slightly worse than that of low-density polyethylene; Good chemical stability, insoluble in any organic solvent at room temperature, and resistant to acid, alkali and various salts; The membrane 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 that of low-density polyethylene. Especially, the thermal oxidation will degrade its performance. Therefore, antioxidants and ultraviolet absorbers should be added to the resin to improve this deficiency. Attention should be paid to the low thermal deformation temperature of high-density polyethylene film under stress. See Table 2-1 for performance parameters of high-density polyethylene.
2.1.2.2 Quality standards
See Table 2-4 for the quality index requirements of high-density polyethylene resin and the provisions of the standard GB 11116-89.See Table 2-5 for the comparison between the new standard resin brand and the original brand.
The new brand is described as follows.
The grade is divided into 4 units. Abbreviation code PE of polyethylene shall be marked in unit 1. The main use or processing method of polyethylene (listed in the first place in Unit 2), the importance of resin, additives, color and state (granular or powdery) [listed in the second place to the fifth place] shall be marked in Unit 2. The colorless and granular resin need not be listed. Mark according to the codes in Table 2-6. The resin density and melt flow rate marked in Unit 3 are only test conditions. The density value is represented by two numbers (see Table 2-7), followed by a letter and three numbers representing the melt flow rate value and test conditions (marked according to the codes in Table 2-8 and Table 2-9). The type of filler or reinforcement material shall be marked in Unit 4, which shall be written in the first digit of a letter code; Its physical state is written with another letter as the second digit of the code (see Table 2-10 Code); The mass fraction is coded with two digits and is written in the third digit (according to the code in Table 2-11).
2.1.2.3 Forming method and use
High density polyethylene resin can be used to form plastic products by injection, extrusion, blow molding and rotary molding.The injection molding machine can be used to inject various types of daily necessities, containers, industrial accessories, medical supplies, toys, shells, bottle stoppers, shields and other products.
The blow molding method can be used to form various hollow containers, ultra-thin films, etc.
Extruder is used to extrude and shape pipes, tensile strips, binding tapes, monofilament, wire and cable sheaths, etc.
In addition, it can also be used to form architectural decorative panels, shutters, synthetic wood, synthetic paper, synthetic films and molded calcium plastic products.
Refer to Table 2-12 for products with different melt flow rates recommended for molding in high-density polyethylene resin.
PE-JA50D012 grade or GB/T13,849-93 standard shall be used for extrusion molding of high-density polyethylene resin for insulated cables. See Table 2-13 for required parameter values of various indicators
When selecting HDPE resin for application, attention should also be paid to the influence of different densities on the properties of polyethylene (see Table 2-14).
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