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High Density Polyethylene HDPE

Time:2018/08/08   Pageviews:21    Share:
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HDPE high density polyethylene

HDPE is a high crystallinity, non - polar thermoplastic resin. High density polyethylene for white particles, non-toxic, tasteless, odourless, melting point is 130 ℃, the relative density is 0.941 ~ 0.960. It has good heat resistance and cold resistance, good chemical stability, high rigidity and toughness, good mechanical strength. Dielectric properties, environmental stress cracking resistance is also good. The melting temperature of 220 ~ 260 ℃. For larger molecular materials, it is recommended that the melting temperature range between 200 ~ 250 ℃. High density polyethylene (hdpe) is a white powder granular product, non-toxic and tasteless, with a density ranging from 0.940 to 0.976 g/cm3. Crystallinity is 80% ~ 80%, softening point is 125 ~ 135 ℃, using temperature is 100 ℃; Hardness, tensile strength and creep are better than low density polyethylene. Wear resistance, electrical insulation, toughness and cold resistance are all better, but slightly worse than low density insulation. Good chemical stability, at room temperature, insoluble in any organic solvents, acid, alkali and various kinds of salt corrosion resistance; The film has little permeability to water vapor and air and low water absorption. Poor anti-aging performance, less anti-environmental cracking than low-density polyethylene, especially the thermal oxidation will reduce its performance. Therefore, the resin needs to add anti-oxygen agents and ultraviolet absorbents to improve this aspect.

Material properties

【 English full name 】 High Density Polyethylene


High density polyethylene

Low pressure ethylene


[basic properties] high density polyethylene is an opaque white waxy material with a lighter specific weight than water, with a specific weight of 0.941~0.960.

[combustion characteristics] inflammable, can continue to burn after the fire, the upper end of the flame is yellow, the lower end is blue, it will melt when burning, there will be liquid dropping, no black smoke coming out, and at the same time, it will give off the smell of paraffin burning.

[main advantages] acid and alkali resistance, organic solvents resistance, good electrical insulation, low temperature, can still maintain a certain degree of toughness. Surface hardness, tensile strength, rigidity and other mechanical strength are all higher than LDPE, close to PP and more tough than PP, but the surface finish is not as good as PP.

[main defects] poor mechanical performance, poor air permeability, easy deformation, easy aging, brittle, brittle lower than PP, easy stress cracking, low surface hardness, easy to scratch. Difficult to print, printing, surface discharge treatment, no electroplating, surface gloss.

[application] used for extrusion of packaging film, rope, woven bag, fishing net and water pipe; Injection molding low-grade daily necessities and shells, non-load-bearing components, plastic box, turnover box; Extrude blown plastic containers, hollow products, bottles.

[injection molding process] there are countless applications of HDPE, ranging from reusable thin-walled beverage cups to 5-gsl cans, which consume one-fifth of the HDPE produced in China. The general melt index of injection molding grade is 5 ~ 10, and there are high fluidity grade with low toughness and high processability. USES include daily necessities and food thin-walled packaging; Tough and durable food and paint cans; High resistance to environmental stress cracking applications such as small engine fuel tanks and 90-gal garbage cans.

General HDPE melting point is 142 ℃ and decomposition temperature is 300 ℃; The adjustable range of injection temperature is large. When we do the injection, generally using temperature is 180 ℃ -- 230 ℃; For olefin is plastic, it's not bibulous, production, without drying, but for the sake of the quality of our products available 60 ℃ temperature drying 1 hr, to floating; The melt viscosity of polyethylene is large, and the flow length ratio is small. Products easy to bring static electricity, the surface easy to absorb. The shrinkage rate is 16‰. The overflow value is 0.05mm. [3]

Product performance:

High density polyethylene for non-toxic, tasteless, odourless, white particles, melting point is 130 ℃, the relative density of 0941-0960, it has good heat resistance and cold resistance, good chemical stability, also has high rigidity and toughness, good mechanical strength, dielectric properties, environmental stress cracking resistance is also good.


Used for extruding packaging film, rope, knitting net, fishing net, water pipe, injection molding lower grade daily necessities and shell, non-load bearing components, plastic box, circulating box, extrusion blow molding container, hollow product, bottle.

Used for hollow forming products and blown film products such as food packaging bags, shopping bags for miscellaneous products, fertilizer lining film, etc.

Historical development

HDPE is a kind of thermoplastic polyolefin produced by ethylene copolymerization. Although HDPE was introduced in 1956, the plastic is not yet mature enough. The generic material is also being developed for new USES and markets. Our domestic hdpe (high density polyethylene here does not include the full density polyethylene plant production of high density polyethylene) with petrochina, sinopec, cnooc, maker of the three companies, by the end of 2006, belongs to the oil in the high density polyethylene device with 4 sets, namely, lanzhou petrochemical hdpe, daqing petrochemical high density polyethylene device, liaoyang petrochemical, high density polyethylene device, jilin petrochemical high density polyethylene

High density polyethylene is usually manufactured by using ziegler-natta polymerization method. Its characteristic is that there is no branched chain on the molecular chain. The polymerization was initiated by using ethylene as raw material and oxygen or organic peroxide as initiator in tubular or kettle reactors.

High density ethylene is an environment-friendly material, which can be recycled when the heating reaches the melting point. Instructions can be as big of plastic raw materials are divided into two categories: "Thermoplastic" () Thermoplastic and Thermosetting plastic "(Thermosetting), Thermosetting plastic is heated to a certain temperature to curing condition, even continue to heat cannot change its state, therefore, products with environmental problems is the Thermosetting plastic products such as tires, is not" Thermoplastic plastic products (such as plastic pallet note: pallet in Hong Kong and Macao is called "plywood"), so not all the "plastic" are not environmental protection.

This is the end of the introduction of High Density Polyethylene HDPE. I hope it can help you.


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