For those who often use film blowing machines, I believe they are familiar with film blowing machines at all, but one thing is a question that film blowing machine operators hate and wonder, that is, what temperature range is the film blowing machine controlled at? Appropriate, because the temperature may directly or indirectly lead to the quality of the film blown by the film blowing machine, it is necessary to control the temperature of the film blowing machine.
At the beginning of the melting section, the temperature can only be melted when the temperature reaches the viscous flow temperature. For crystalline resins, the viscous flow temperature is equal to the melting point temperature. Then continuously compress and increase the melting layer, the temperature needs to be continuously increased to make the resin molecular chain lengths vary, and the polymers with different thermal motion energies are all melted successively. Therefore, after the temperature at the end of the melting section is established, it can be determined as a The other parts of the upper part are heated linearly.
The key points for controlling the extrusion temperature of the film blowing machine are:
Different kinds of resins, blowing film process temperature is different;
For the same resin, the model and melt index are different, and the process temperature of the blowing film is different. The larger the index is, the better the fluidity is and the lower the temperature.
For the same resin and different thickness films, the process temperature is also different. For thick films, the process temperature can be higher, and the temperature of the film opening can also be higher, which is conducive to reducing viscosity and improving productivity.