I. How polyethylene is produced

Polyethylene is a polymer material which can be obtained by polymerization of ethylene monomer in the presence of a catalyst. There are generally two ways of polymerization as follows:

1. Free radical polymerization

Free radical polymerization is a heated and pressurized method of polymerization that involves placing ethylene and an initiator in a reactor containing air and then polymerizing under high temperature and pressure. The polyethylene produced by this method is commonly used to make plastic film, plastic bags, etc.

2. Ionic polymerization

Ionic polymerization is a method of polymerization by the action of anions or cations, which requires the use of a special catalyst to promote the polymerization of ethylene. The polyethylene obtained by this way of polymerization is usually more uniform and stable than that obtained by free radical polymerization, so it is widely used in the manufacture of high-performance materials.

Second, the production process of food packaging bags

Food packaging bags are usually made of polyethylene film, the following describes its production process.

1. Raw material preparation

First of all, you need to mix the polyethylene particles, lubricants, antioxidants and other raw materials. Among them, the lubricant can improve the fluidity of the material, antioxidant can prevent the material aging.

2. Extruding and plasticizing

The raw materials are fed into the plasticizer and heated to form a melt, and color masterbatch and other materials are added, then the molten materials are extruded into film form.

3.Cooling and Shaping

The extruded film is cooled through a cooling machine, stretched and shaped under the action of a traction machine to obtain the desired thickness and width.

4. Printing and laminating

The obtained film is fed into the laminating machine and laminated with another layer of polyethylene film to form a double-layer film, on one of which the information of the bag is printed.

5.Finished product packaging

The composite film will be cut into the specified size, after folding and cutting edges, in the sealing machine for heat sealing, the formation of the final product - food packaging bags.

In short, the polyethylene material used in food packaging bags is made by way of polymerization and processing and is processed into a product through a specific manufacturing process. These bags have excellent properties such as lightweight, moisture-proof, waterproof, durable and hygienic, providing convenience and security to the food industry.