PET Crystallization Machine

 

The maximum degree of crystallization of PET is about 55%, which can produce ordered crystallization zones. The crystallization temperature range of PET is 120~220℃, the crystallization time is 1~2 hours, and the crystallization time is inversely proportional to the pre-crystallization temperature. The higher the drying temperature is, the higher the drying rate is. The shorter the drying time, the lower the moisture content of raw materials after drying. The drying temperature of stirring crystallizer is usually between 120 and 160 ° C. The drying temperature of dehumidification is between 160 and 180℃. PET is boiled by air flow while drying. The higher the drying wind speed, the higher the relative speed of PET and air flow, so the drying time will be shortened, but the dust generated by the system will also increase correspondingly, and it is necessary to consider removing too much dust. The lower the moisture content of hot air (dew point), the faster the drying rate of raw materials, and the lower the corresponding balance moisture of raw materials. In the actual processing process, taking into account the processing cost and energy consumption, for the bottle embryo or injection molding, the dew point value is less than -50℃ to meet the dry water content of the raw material is less than 50ppm. For extrusion molding, the dew point value is less than -40℃ to meet the dry water content of the raw material is less than 100ppm.