Our commonly used plastic bag materials are as follows:
Polyethylene (PE), referred to as PE. It is a high molecular organic compound obtained by the addition polymerization of ethylene. Polyethylene is recognized as the best food contact material in the world. It is non-toxic, tasteless, and tasteless, in line with food packaging hygiene standards. Polyethylene film, light weight, transparent, moisture-proof, oxygen-proof, acid-proof, alkali-proof, air-tight, heat-sealing and other properties. It is called “plastic flower”. It is the most important and most important material for plastic packaging printing.
Low-density polyethylene
Low-density polyethylene, or LDPE for short, is the largest variety in the plastic packaging and printing industries in various countries. It has a specific gravity of 0.92 to 0.93 and can float in water. The crystallinity is low (60%), and the bulk polymerization is carried out under a pressure of 1000 to 3000 kg/cm 2, so it is also called high-pressure polyethylene. At 23 degrees Celsius, the density is about 0.92. It has poor calendering formability and is suitable for processing into tubular films by blow molding. Suitable for food packaging, fiber packaging and daily chemical packaging.
HDPE-High Density Polyethylene
High-density polyethylene, referred to as HDPE. The density is 0.941 to 0.965g/cm 3. Using low it is also called low pressure polyethylene. It is milky white, indicating poor gloss. The treated film can be blown and extruded with a T-die. Heat resistance, cooking resistance, cold resistance, cold resistance, moisture-proof, gas-proof, good insulation performance, not easy to break. The most common are supermarket shopping bags and plastic vest bags.
Polyvinyl chloride
Polyvinyl chloride is abbreviated as PVC, and its molecular formula is (CH-CH)n. It is the most important type of vinyl polymer and the second largest plastic in the world after polyethylene. The proportion of domestic production of plastic bags is the highest. In the printing industry, polyvinyl chloride color calendered film and transparent glass film are usually used for packaging and decoration of books, folders, bills, etc.
Shrink film-Shrink film
Shrink film is a thermoplastic film that is stretched and oriented during production, and shrinks during hot air treatment or infrared radiation during use. After heat treatment, the film is tightly wrapped around the package, and the shrinkage force reaches the maximum during the cooling stage, which can be stored for a long time.
BOPP-Biaxially oriented polypropylene film
Biaxially oriented polypropylene film, also known as biaxially oriented polypropylene film, the abbreviation code BOPP is characterized by stretch molecular orientation, mechanical strength, folding strength, gas density and moisture resistance better than ordinary plastic films. Compared with cellophane, the unit price is lower than that of cellophane. Because the film has excellent transparency, the color reproduction after printing is particularly bright and beautiful, and it is an important substrate for plastic composite flexible packaging.
