Why does the bubble tube of the film with added PE blow-molding flame-retardant master batch take on a reed-like shape?

This is mainly caused by problems in the process, and it can be adjusted through the following solutions. 

First: The regular gourd shape of the bubble tube is caused by the too small clamping force of the traction roller, or the influence of the regular change of the mechanical transmission resistance on the rotation speed of the traction roller. In this regard, the clamping force of the traction roller should be appropriately increased, and the mechanical transmission part of the traction device should be overhauled to make the rotation speed of the traction roller stable. 

Second: The irregular gourd shape of the bubble tube is due to the unstable traction speed and the too large air pressure of the cooling air ring. In this regard, the traction speed should be adjusted to make its operation stable; the air pressure of the air ring should be appropriately reduced.