All Size Printing OPP PET Poly Zipper Bag For Phone Case USB Cable Packing

Knowledge sharing (production methods of PE plastic bags):

A. Slurry method. Polymerization in a diluent (such as hexane) was the earliest industrialized method and the method with the largest production volume so far.
B. Liquid phase bulk method. Polymerize in liquid propylene at 70°C and 3MPa.
C. Gas phase method. Polymerizes propylene in gaseous state. The latter two methods do not use diluent, have a short process and low energy consumption. The liquid phase bulk method has now shown the advantage of catching up from behind. Molding characteristics of PE plastic bags:
A. Crystalline material has low hygroscopicity, is prone to melt rupture, and is prone to decomposition in long-term contact with hot metal.
B. The fluidity is good, but the shrinkage range and value are large, and shrinkage cavities, dents, and deformation are prone to occur.
C. The cooling speed is fast, the pouring system and cooling system should dissipate heat slowly, and pay attention to controlling the molding temperature. It is easy to orientate when the material temperature is low and high pressure. When the mold temperature is lower than 50 degrees, the plastic parts are not smooth and are prone to poor welding and flow marks. Above 90 degrees, warping deformation may
easily occur
D. The plastic wall thickness must be uniform to avoid lack of glue and sharp corners to prevent stress concentration.