Blow Molding Machine? Blow molding machine? Preform mold? You should be aware of these products. Today, as its supplier, we are here to introduce you to the related knowledge of the product bottle blowing machine-preform. If you are also plagued by this problem, then the following introduction must be correct. You help, read it together.
The bottle blank of the bottle blowing machine, also known as the parison, is injection molded of PET pellets. It requires that the proportion of recycled materials should not exceed 10%, and the number of recycling should not exceed twice. The preform after injection molding or the preform after heating must be cooled for more than 48 hours, and the used preform storage time can not exceed 6 months. Different production dates, especially preforms with long intervals, cannot be mixed. The main reason is that The type of raw materials used in the preform, the ratio of the mixed secondary material and the residual stress in the preform are different, and these factors have a significant impact on the molding process of the blow-molding bottle, and should be specifically treated according to actual conditions. Because PET has a strong water absorption, it must be taken care of in moisture storage, and must be effectively dehumidified and dried before processing, drying conditions are usually 150 ~ 180 °C for 4 hours, and to prevent plastic particles re-absorb moisture, must Insulation at temperatures above 140°C, to prevent yellowing of the plastic during shutdown, the dehumidifying dryer needs to be cooled to 100°C without dehumidifying and only keeping warm. In addition, PET injection molding when the material temperature is too high, the screw shear force is too large or too fast when the acetaldehyde is easy to produce acidification, usually after molding PET bottle acetaldehyde content must be less than 3ppm, preform before crystallization Need a certain moisture content, generally required at about 1000 ppm, at least require more than 900ppm, so the preforms in the injection need to be placed for some time before the water content can reach the required crystal.