What is the process of blown film processing

The production process of blown film processing is roughly as follows:

Raw material plasticization extrusion → inflation traction → air ring cooling → herringbone clamp → traction roller traction → corona treatment → film winding

However, it is worth emphasizing that the characteristics of the blown film are closely related to the main parameters of the production process. Therefore, in the entire blown film process, it is necessary to improve the control of the main parameters of the processing technology, standardize the actual operation of the processing technology, ensure the smooth development of production and manufacturing, and obtain high-quality film products. In the process of processing polyethylene blown film, the main focus is on controlling the main parameters of the following processing techniques:

1. Extruder temperature

When blowing low-density polyethylene (LDPE) film, the extrusion temperature is generally controlled between 160 ℃ and 170 ℃, and it is necessary to ensure that the extruder temperature is uniform. If the extrusion temperature is too high, the resin is easily decomposed and the film will become brittle, especially when the vertical tensile strength is significantly reduced;

If the temperature is too low, the resin plasticization will be poor, and smooth stretching cannot be carried out. The tensile strength of the film is also low, and the glossiness and clarity of the surface are poor, even resulting in patterns like wood rings and unmelted crystal nuclei (fish eyes).

2. Inflation ratio

The inflation ratio is one of the key control points in the blown film processing flow, which refers to the ratio between the diameter of the inflated film bubble and the diameter of the non inflated tube ring. The inflation ratio is the transverse expansion ratio of the film, which is actually a transverse stretching effect on the film. The stretching effect will have a certain degree of effect on the molecular structure of the plastic, and the expansion ratio will increase, thereby improving the transverse compressive strength of the film. However, the inflation ratio should not be too high, otherwise it can easily lead to unstable film bubbles and wrinkles on the film. Therefore, the inflation ratio should be appropriately coordinated with the traction ratio. Generally speaking, the inflation ratio of low-density polyethylene (LDPE) film should be controlled between 2.5 and 3.0.

If you have any questions about the production process of blown film processing, please feel free to consult the editor of Kunshan Juxinchang Company!