The difference between high-pressure PE plastic and low-pressure PE plastic:
High-pressure polyethylene refers to polyethylene produced by a high-pressure process, and low-density polyethylene (LDPE). Low-pressure polyethylene refers to a polyethylene produced by a low-pressure process that can produce high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE).
LDPE low-density polyethylene is a plastic material, which is suitable for various molding processes of thermoplastic molding and has good molding processability. The main purpose is to make film products, but also for injection molding products, medical appliances, medicine and food packaging materials, blow molding hollow molded products, etc.
HDPE is a non-polar thermoplastic resin with high crystallinity. The appearance of the original HDPE is milky white, and the thin section is translucent to a certain extent. PE has excellent resistance to most domestic and industrial chemicals. Certain types of chemicals can cause chemical corrosion, such as corrosive oxidizers (concentrated nitric acid), aromatic hydrocarbons (xylene) and halogenated hydrocarbons (carbon tetrachloride).
The polymer is non-hygroscopic and has good water vapor resistance, and can be used for packaging purposes. HDPE has good electrical properties, especially the high dielectric strength of the insulation, making it very suitable for wires and cables. Medium to high molecular weight grades have excellent impact resistance, even at room temperature and even at low temperatures of -40F.
The unique characteristics of various grades of HDPE are the proper combination of four basic variables: density, molecular weight, molecular weight distribution and additives. Different catalysts are used to produce customized polymers with special properties. The combination of these variables produces HDPE grades for different purposes; achieving the best balance in performance.
LLDP linear low-density polyethylene is non-toxic, tasteless, and odorless milky white particles with a density of 0.918～0.935g/cm3. Compared with LDPE, it has a higher softening temperature and melting temperature, has the advantages of high strength, good toughness, high rigidity, heat resistance, good cold resistance, etc. It also has good environmental stress cracking resistance, impact resistance, and Properties such as tear strength.
It is resistant to acids, alkalis, organic solvents, etc. Uses Suitable for making agricultural film, packaging film, composite film, pipe, hollow container, wire, cable insulation layer, etc.
In summary, high-pressure polyethylene: using polymer-grade ethylene as the raw material, oxygen or organic peroxide as the catalyst, in the tubular reactor cargo tank reactor, using 130-280Mpa ultra-high pressure and 300 degrees Celsius high temperature process It is made by polymerization. It is low-density polyethylene (LDPE); generally less than 0.925.
Low-pressure polyethylene: using high-purity ethylene as the raw material, propylene or 1-butene as the comonomer, and alkane as the solvent, in the presence of a highly active catalyst, using a certain temperature and pressure for solution polymerization, after separation, It is made by drying, mixing and granulating. It is high-density polyethylene (HDPE). Generally, the density is greater than 0.94.