As a plastic bags supplier, Fengyi will introduce the differences between the HDPE and LDPE plastic bags.
HDPE is non-toxic, tasteless and odorless. Its density is 0.940～0.976g/cm3. It is a product of polymerization under low pressure conditions under the catalysis of a catalyst, so high-density polyethylene is also called low-pressure polyethylene.
HDPE is a non-polar thermoplastic resin with high crystallinity produced by copolymerization of ethylene. The appearance of the original HDPE is milky white, and the thin section is translucent to a certain extent. It has excellent resistance to most domestic and industrial chemicals. It can resist the corrosion and dissolution of strong oxidants (concentrated nitric acid), acid-base salts and organic solvents (carbon tetrachloride). The polymer does not absorb moisture and has good water vapor resistance, and can be used for moisture-proof and anti-seepage purposes.
The disadvantage of HDPE is that its aging resistance and environmental stress cracking properties are not as good as LDPE, especially thermal oxidation will reduce its performance. Therefore, when high-density polyethylene is made into plastic coils, antioxidants and ultraviolet light absorber are added to improve its shortcomings.
LDPE is non-toxic, tasteless and odorless. Its density is 0.910～0.940g/cm3. It is polymerized with oxygen or organic peroxide as a catalyst under a high pressure of 100～300MPa. It is also called high pressure polyethylene.
Low-density polyethylene is the lightest variety among polyethylene resins. Compared with high-density polyethylene, its crystallinity (55%-65%) and softening point (90-100℃) are lower; it has good flexibility, elongation, transparency, cold resistance and processability; its chemistry Good stability, resistance to acid, alkali and salt solutions; good electrical insulation and air permeability; low water absorption; easy to burn. It is soft in nature, with good extensibility, electrical insulation, chemical stability, processing performance and low temperature resistance (-70℃).
The disadvantage of LDPE is its poor mechanical strength, moisture barrier, gas barrier and solvent resistance. The molecular structure is not regular enough, the crystallinity (55%-65%) is low, and the crystal melting point (108-126℃) is also low. Its mechanical strength is lower than that of high-density polyethylene, and its impermeability coefficient, heat resistance and solar aging resistance are poor. It is easy to decompose and change color under sunlight or high temperature, resulting in performance degradation. Therefore, when low-density polyethylene is made into plastic coils, antioxidants and ultraviolet absorbers are added to improve its shortcomings.
HDPE plastic is generally opaque. After biting with teeth, white stubble marks will appear at the cracks. The material is relatively brittle and hard, and it is often used for packaging products. However, LDPE is relatively soft, has good toughness, good transparency, and has a relatively slippery feel, and the sound produced by tearing by hand is relatively small.
According to the purpose, LDPE is widely used in light packaging materials such as waterproof carton lining, plastic wraps, and so on. It is also used in computer hardware covers and packaging, wash bottles, and more. HDPE is used in strong packaging materials such as plastic milk bottles, drums, bulk containers, bottle caps for industrial use. Also, it is used in pipes and tubing, plastic chairs and tables.
Our company has the HDPE plastic bags of high quality for sale, welcome to consult!
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