We should know the products of bottle preform mould, bottle blowing machine, and bottle blowing mould. Today we will introduce the product blowing machine-bottle preform knowledge to us here. The problem is troubled, then the following introduction can definitely help you, let's read it together.

The preform of the blow molding machine is also called parison. It is formed by injection molding of PET pellets. It requires that the proportion of recovered material cannot exceed 10%, and the number of recovery can not exceed two times.

Preforms after injection molding or preforms that are reused after heating must be cooled for more than 48 hours, and the preform storage time must not exceed 6 months. Different production dates, especially preforms that are too long, cannot be mixed. The first reason is due to the different types of raw materials used in the preform, the proportion of the secondary material mixed in, and the residual stress in the preform. These factors have a significant impact on the blow molding process and should be treated in detail according to the actual situation. Because PET has strong water absorption, it is necessary to pay special attention to moisture resistance during storage, and it must be dehumidified and dried before processing. Drying conditions are generally carried out at 150-180 ° C for 4 hours, and in order to prevent plastic particles from absorbing moisture again, It is necessary to keep the temperature above 140 ° C. In order to prevent the plastic from turning yellow when the machine is stopped, the dehumidifier dryer needs to be cooled to 100 ° C. It is kept warm without dehumidification.

In addition, if the material temperature is too high, the screw shear force is too high or the speed is too fast during PET injection molding, acetaldehyde will easily cause acidification. Generally, the acetaldehyde content of the PET bottle after molding must be less than 3ppm, and the preform is crystallized. A certain moisture content is required before, generally about 1000 ppm, at least 900 ppm or more, so the bottle embryo needs to be placed for a period of time before the water content reaches the requirements before crystallization.

We not only understand the product preform product, but also understand the close relationship between it and the product blowing machine.