Influencing Factors And Countermeasures Of Film Blowing Transparency Of Film Blowing Machine

The commonly used film blowing material is polyolefin, which is a highly crystalline polymer. Therefore, an important factor affecting transparency is the resin raw material. Of course, improving the quality of the film blowing machine is also a consideration, but the film blowing machine technology itself has little influence on the transparency of the film blowing. Transparency refers to the percentage of transmitted light with a scattering Angle less than 0.1° that impinges on the incident light intensity when the incident light passes through the sample. The higher the transparency of the film, the clearer the remote image through the film. Transparency is related to the crystallinity of the film and the surface flatness, the lower the crystallinity, the more amorphous areas, the more flat the surface, the higher the transparency.
It can be seen that the best way to improve the transparency of the film is to use lower crystallinity and small spherulites. This can reduce the surface tension of the film and thus reduce the thickness of the film. In addition, adding a certain amount of plasticizer to the film can also improve the transparency of the film. The most advanced film blowing technology can only improve transparency to a certain extent.
In view of the above, in the case of relatively good raw materials, the problem of film transparency occurs again, how to solve it? First of all, it is necessary to consider that the extrusion temperature of the film blowing machine is too low, and the melt is not plasticized well. This problem can be solved only by increasing the melt temperature. In addition, the poor cooling after blowing the film will also affect the transparency, and the corresponding mechanism is to increase the cooling air volume.
Back to the raw material, the more moisture of the resin ball will also affect the transparency of the blown film, this problem is relatively simple, only the resin ball should be fully dried. However, if it is glass fiber, it needs special treatment, such as coating a transparent protective film on the surface of the resin ball, so that it can avoid reducing the transparency of the resin ball due to excessive moisture.
In addition, there are many ways to improve the optical properties of the film, such as adding a small amount of LDPE to linear low-density polyethylene or metallocene polyethylene, and adjusting the interlayer density in the three-layer film structure.
In summary, the processing technology affecting the film is nothing more than cooling, raw material polyethylene resin parameters, additives, temperature, formula design. According to the specific analysis of different problems, the problem can be solved easily.