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The characteristics and applications, advantages and disadvantages of LDPE plastic materials

February 24, 2024

Scientific name

Low density polyethylene, high-pressure polyethylene.


Ethylene - a gas produced in petroleum refining.


Polyethylene natural color is a semi transparent white waxy material with a lighter specific gravity than water, soft and resilient, slightly elongating, non-toxic, and odorless.

Combustion characteristics

Flammable, can continue to burn after leaving the flame. The upper end of the flame is yellow and the lower end is blue. It will melt during combustion, with liquid droplets and no black smoke coming out. At the same time, it emits the odor of paraffin burning.


Acid and alkali resistance, organic solvent resistance, excellent electrical insulation, and can still maintain a certain degree of toughness at low temperatures.


Poor mechanical performance, poor air permeability, easy deformation, aging, brittleness, stress cracking, low surface hardness, and easy scratching. Difficult to print, surface discharge treatment is required during printing, electroplating is not allowed, and the surface is dull.

Injection molding performance

Low molecular weight polyethylene with a melting point of 120 ℃, very similar to paraffin. The general melting point of polyethylene is 140 ℃, and the decomposition temperature is 300 ℃. The adjustable range of injection molding temperature is large, and it is commonly used for material replacement and washing machines of other raw materials. During injection molding, the general operating temperature is between 170 ℃ and 220 ℃. As it is an olefinic plastic, it does not absorb water and does not need to be dried during production. However, for product quality, it can be dried at 60 ℃ for 1 hour to discharge floating water. Polyethylene has a high melt viscosity and a low flow length ratio, and thin-walled products may lack adhesive. Therefore, the gate and runner are relatively large; The product is prone to static electricity and the surface is prone to dust absorption. The shrinkage rate is 16 ‰. The overflow value is 0.05mm.


1. Used for extruding packaging films, coated films, and hoses.

2. Used for injection molding low-end daily necessities and casings.

3. Used for extruding blow molded containers.