The structural difference between metallocene linear low-density polyethylene (MLLDPE) and traditional linear low-density polyethylene (LLDPE) was compared, and the mechanical properties, heat-sealing properties, optical properties and rheological behavior of the two blown films were compared. The results showed that: The type and distribution of comonomers have a great impact on performance; MLLDPE with longer branched chains and more uniform distribution has better mechanical properties, heat sealing properties and optical properties; MLLDPE has more stable bubbles during blow molding, while the processing speed of LLDPE is faster.
LDPE is non-toxic, tasteless, and odorless, with a density of 0.910-0.940g/cm3. It is polymerized under a high pressure of 100-300MPa with oxygen or organic peroxide as a catalyst. It is also called high-pressure polyethylene.
Advantages: good flexibility, extensibility, transparency, cold resistance and processability; its chemical stability is good, it can resist acid, alkali and saline solution; it has good electrical insulation and air permeability; low water absorption; Easy to burn.
It is soft in nature, has good extensibility, electrical insulation, chemical stability, processing performance and low temperature resistance (can withstand -70°C).
Disadvantages: The disadvantage is that its mechanical strength, moisture barrier, gas barrier and solvent resistance are poor. The molecular structure is not regular, the crystallinity (55%-65%) is low, and the crystalline melting point (108-126°C) is also low. Its mechanical strength is lower than that of high-density polyethylene, and its anti-seepage coefficient, heat resistance and sunlight aging resistance are poor. It is easy to age and decompose and change color under sunlight or high temperature, resulting in a decline in performance. Antioxidants and UV absorbers are added to improve its deficiencies.
Metallocene linear low-density polyethylene (MLLDPE) is a new type of thermoplastic, which uses metallocene (MAO) as a polymerization catalyst, and has the advantages of ductility, transparency and toughness.
The performance of ultra-low temperature PE-MLLDPE has the following core values:
- Ultra-low temperature heat sealing performance at 95 degrees Celsius
It can meet the application requirements of ultra-low temperature heat-sealed packaging, and the adhesive effect will be produced at 95 degrees Celsius.
- Puncture resistance, high flexibility
Excellent puncture resistance and obvious softness, which can effectively prevent sharp-edged objects from piercing the packaging.
- Potential applications
Packaging with ultra-low temperature heat sealing requirements; packaging of sharp-edged foreign objects.