Understanding of finished materials

Raw materials for plastic bags

Polyethylene (PE), abbreviated as PE. It is a polymer organic compound obtained by addition polymerization of ethylene. Polyethylene is recognized as the best material for food contact in the world. Non-toxic, odorless, odorless, in line with food packaging hygiene standards. Polyethylene film, light and transparent, with moisture, oxygen, acid, alkali, air tightness, excellent heat sealing properties. It is known as the "flower of plastic." It is the most used and most important material for plastic packaging printing.

PVC--polyvinyl chloride

PVC is abbreviated as PVC and its molecular formula is (CH2-CH2)n. It is the most important category of vinyl polymer and it is the second largest plastic type in the world after polyethylene. The domestic output ranks first in plastics. In the printing industry, PVC, colored calendered films and clear glazing films are often used to make envelopes for books, folders, tickets, and other covers.

Shrinkfilm--Shrink Film

Shrink film is a thermoplastic film that is stretched and oriented during the production process, and shrinks during hot air treatment or infrared irradiation during use. After the heat treatment, the film is tightly wrapped around the packaged material. The shrinkage force reaches a maximum during the cooling stage and can be stored for a long time.

LDPE--Low Density Polyethylene

Low-density polyethylene, LDPE for short, is the largest variety in the plastic packaging and printing industry in various countries. The specific gravity is 0.92 to 0.93, which can float on water. Low crystallinity (60%), bulk polymerization at pressures of 1000-3000 kg/cm2, is also called high-pressure polyethylene. At 23 degrees Celsius, the density is around 0.92. Due to poor calenderability, it can be processed into a tubular film by blow molding. Applicable to food packaging, fiber products packaging, daily chemical products packaging.

HDPE--High Density Polyethylene

High-density polyethylene, referred to as HDPE. The density is 0.941 to 0.965 g/cm3. With low-pressure polymerization, it is also known as low-pressure polyethylene. Milky white, indicating poor luster. Processed films can be blown and T-die extruded. It is resistant to heat and cooking, cold and resistant to freezing, moisture-proof, air-proof, and good insulation performance. It is not easily damaged and its strength is twice that of LDPE. Extremely easy to open. Strong paper-like, known as "paper-plastic film."

BOPP--biaxially oriented polypropylene film

Biaxially oriented polypropylene film, also known as biaxially oriented polypropylene film, English abbreviation code BOPP, characterized by tensile molecular orientation, mechanical strength, folding strength, gas density, moisture barrier properties better than ordinary plastic film. Compared with cellophane, unit price is lower than cellophane. Due to the excellent transparency of this film, it is particularly important for plastic composite flexible packaging to reproduce the bright and beautiful appearance after printing.

Toxicity identification of plastic bags

The commonly used food plastic bags are mostly made of polyethylene film. The film is non-toxic and can be used for holding foods. There is also a film made of polyvinyl chloride, polyvinyl chloride itself is also non-toxic, but additives added according to the use of the film are often harmful substances to the human body and have a certain degree of toxicity. Therefore, such films and plastic bags made of the films are not suitable for containing foods. If you want to identify PVC plastic bags and polyethylene plastic bags, use the following simple method to identify.