What are the types of materials for plastic packaging bags?
Plastic is an indispensable material in our modern society, ranging from satellites and airplanes to mobile phones and ballpoint pens. Plastics can be seen everywhere, and these plastics are petrochemical products. Plastic film is one of the varieties, and plastic bags are storage bags made of plastic films. There are roughly five types of plastics that are made into plastic bags:
(1) Polyvinyl chloride (PVC) In the 1950s and 1960s, most of my country's plastic bags were made of polyvinyl chloride, because they contained additives to improve processing performance and plasticizers to improve film flexibility. It is toxic and should not be used for food, so it is rarely seen in the market except for special non-toxic hard films used for packaging.
(2) Low-pressure polyethylene (HDPE) HDPE film is generally used in places requiring high stretching and anti-seepage. HDPE films are also commonly used in merchandise bags, grocery bags and food packaging. In daily life, commodity bags that require high strength, good waterproofness and good impermeability are all made of this product.
(3) High pressure polyethylene (LDPE) The film made of LDPE has good optical properties, strength, flexibility, sealing, slow odor diffusion and chemical stability. Because of its excellent performance and processability, coupled with its non-toxicity and relatively low price, most of the plastic bags currently used are such products.
⑷ Polypropylene (BOPP) BOPP film is the abbreviation of biaxially oriented polypropylene film. It is a very important flexible packaging material. It is colorless, odorless, tasteless, non-toxic, and has high tensile strength, impact strength, rigidity, Strong toughness and good transparency. After corona treatment, BOPP film has good printing adaptability and can be printed in color to obtain exquisite appearance effect, so it is often used as the surface layer material of composite film. Now colorful food, cold drinks packaging films are made of BOPP.
