What is the production process of plastic bags?

What is the production process of plastic bags?

The first step is film blowing

Blowing film is a plastic processing method, which refers to a plastic processing process of heating and melting plastic particles and then blowing into a film. It is the first step of making plastic bags.

If it is the film blown out with new particles, the color is bright, clean and sanitary, the finished product stretches well, the weight is large, the quality of plastic bags is good, can be used for food packaging. If the plastic particles made of recycled waste plastic, in the blowing film usually add color masterbatch in the raw material particles, made of film is prone to uneven coloring, brittle and easily broken phenomenon, made of plastic bags of poor quality, low price. The plastic bags made of this kind of film are not sanitary and cannot come into direct contact with food.

"Plastic particles" account for most of the cost of finished plastic bags, and the price of plastic particles fluctuates with the price of oil. In recent years, the international crude oil price has been rising all the way, so has the production cost of plastic bags.

The second step color printing

There are many ways of color printing, common printing methods are roller printing, gravure printing, screen printing. Roller printing and gravure printing are the whole roll printing of blown plastic film, which is mechanical printing with fast printing speed and suitable for mass production. If you use screen printing, you must first cut the film into a single volume, and then manually single printing. The printing speed is slow, but this makes the plastic bag text pattern ink thick, strong three-dimensional sense.

Color printing here involves a "plate making" problem, each color needs to do a plate, each plate is a steel bucket, the production of public welfare is also more complex.

Step 3 bag making

Roller printing, intaglio printing good film is generally used to make bag machine ironing, cutting into plastic bags; Screen printed single plastic block must be manually ironed, tools such as electric iron, thermal bonding machine.