According to material: PE bags are divided into LDPE, LLDPE and HDPE, etc. According to the production process, it is divided into: PE flat pocket, ziplock bag, zipper bag, envelope bag, punching handbag, hand-held handbag, zipper bag, PE film. 1. PE flat bag is the simplest production process. After the film is blown by the machine, it is cut into bags one by one on the bag making machine, and the bottom is sealed. 2. The self-sealing bag is a bone strip when the film is blown by the machine, which can be manually sealed. Unlike zipper bags, these two types of bags are generally easy to confuse. 3. The zipper bag is a bag made of PE film with 2 zipper chains on it (this zipper chain is made separately). Generally, there are relatively wide indentations on both sides of the bag, while the ziplock bag does not. Ziplock bags are printed in fewer colors, while zipper bags can be printed with complex patterns. 4. The envelope bag has a tongue like an envelope. A strip of adhesive is attached to the tongue, and the bag can be sealed by folding it over. More general clothing is used. There is also a courier bag, which is actually a type of envelope bag. 5. Punching the tote bag is to punch a hole at the appropriate position on the top of the flat pocket to facilitate the lifting of the bag. 6. The hand-held tote bag is to add a plastic film strip on the top of the bag to facilitate the bag to be lifted. This process is labor-intensive and the cost is relatively high. 7. The zipper bag is to install a zipper strip and a zipper cap at the seal of the bag. 8. PE film is a film that is not made into a bag after being blown out by the machine. It is also divided into stretch film and shrink film. Commonly used in the market are count-by-piece and count-by-length (roll). (Personal) small bags are mainly used for small accessories packaging. Electronic product accessories bags have anti-static effect. The bag mouth is divided into flat mouth and self-sealing structure. It is necessary to cut by yourself (for material packaging) and print cuts (for supermarkets). In addition, the plastic wrap made of PE material can also be called PE bag. Note that the plastic wrap that is in direct contact with food must be made of PE material (the other is generally PVC), which is safer for the human body. Distinguishing method: The transparency, stretchability and viscosity of PVC plastic wrap are stronger than PE plastic wrap. When the PVC plastic wrap is on fire, the flame will turn black, black smoke, and a pungent smell. It will not drip oil, and it will automatically go out after leaving the fire source. When the PE plastic wrap is burning, the flame is yellow, tasteless, dripping oil, and can continue to burn after leaving the fire source.