Method of preparing downward-blowing water-cooling blow-molding polyethylene membrane

Abstract

The invention relates to a manufacturing method of a downward blowing water-cooling blow polyethylene film. The invention is characterized in that downward blowing wind-cooling is first carried out to polyethylene bulb which is extruded out of a finish mold and water-cooling is carried out thereof so as to implement the sudden reduction of the temperature of a fused mass film. The temperature of the fused mass film is reduced rapidly to ensure that the viscosity of the fused mass is increased rapidly, the active capability of molecular chain is weakened, the crystallisation process is not perfect, the formed crystal is small, the film with low degree of crystallisation has wider melting temperature range, good transparency and flexible performance; meanwhile, after being cooled by water, the film adsorbs part of the low molecules which are separated out of the surface and reduces the peculiar smell of the film.

Description

technical field [0001] The invention relates to a manufacturing method of a blown polyethylene film, in particular to a polyethylene film produced by a down blowing water cooling method. Background technique [0002] In the process of producing polyethylene film, in addition to the given formula, its cooling process will also have a great impact on the quality and performance of the product. There are two known cooling processes for the production of polyethylene film. One is the cast polyethylene film produced by casting equipment. On the roll, the film is not easy to form large crystals during this process, so the transparency of the film is better, the stiffness of the film is small, and the softness is better. The other is the upward air cooling method. The polyethylene melt flowing out of the die relies on the air ring surrounding the die lip of the die to blow out the polycooling air curtain outside the film bubble to cool it as soon as possible. This cooling method m...

AI Technical Summary

Problems solved by technology

The other is the upward air cooling method. The polyethylene melt flowing out of the die relies on the air ring surrounding the die lip of the die to blow out the polycooling air curtain outside the film bubble to cool it as soon as possible. This cooling method makes the polymer Molecules have more time to arrange into the crystal lattice, so it is easy to form large crystals, which affects the transparency of the film, and has high stiffness and poor softness. Moreover, due to the precipitation of low molecular weight substances during the film forming process, the produced film has an odor also bigger