First, PET slices were injection molded into preforms t […]
First, PET slices were injection molded into preforms to prepare blown bottles. Requires the proportion of the second recycled material can not be too high Recycling times can not be more than twice, and the molecular weight and viscosity can not be too low. Molecular weight 31000-50000 Intrinsic viscosity 0.78-0.85cm3 g Injection molding of the preform to be stored for more than 48h before use. After heating the preform is not used, must be stored for more than 48h to re-use. The preform can not be stored for more than six months.
Should be easy to inflatable, easy to shape the information, the quality of the preform depends on the merits of the pros and cons of PET data. And to develop a reasonable preform molding process. Experiments indicate that the same viscosity PET material forming the preform, the import of raw materials than the domestic material easy to blow molding; and the same batch of preforms, the production date is different, the blow molding process may also have a greater difference. The quality of the preform determines the difficulty of the blow molding process, the requirements of the preform is pure, transparent, no impurities, no color, point length and the surrounding cornea appropriate.
The heating of the preform is done by heating the oven. Automatic adjustment. Oven in the oven by the far infrared light emitted far infrared radiation on the preform, from the bottom of the oven fan for thermal cycling, so that the oven temperature uniformity. The preform is moved in the oven while moving, so that the preform wall is heated evenly.
Its height, cooling plate adjustment is very important, so that the oven to play a better role. If the adjustment is not appropriate, easy to blow when the expansion bottle mouth, hard neck and other defects.