![]() Preforms should not be stored for more than six months. The preforms that have not been used up after heating must be stored for another 48 hours to be reheated. ![]() Injection molded preforms must be stored for 24 hours to be used above. According to the National Food Safety Law, secondary reclaimed materials should not be used for food or pharmaceutical packaging. When preparing a blow molded bottle, the PET slice is first injection-molded into a preform, which requires that the proportion of the secondary regrind should not be too high (less than 5%), the number of recovery should not exceed two, and the molecular weight and viscosity should not be too low (molecular weight 31000- 50000, intrinsic viscosity 0.78-0.85 cm3/g). Important factors affecting the PET bottle blowing process are preforms, heating, pre-blowing, molds and production environments. The operation has also evolved from the past manual button type to the current full computer control, which greatly reduces the difficulty of the process operation and increases the stability of the process. Equipment production capacity continues to increase, from the previous production of thousands of bottles per hour to the current production of tens of thousands of bottles per hour. With the continuous advancement of technology and the scale of production, PET bottle blowing machines are becoming more and more automated, and production efficiency is getting higher and higher. The author mainly discusses the molding process of pressurized beverage bottles in cold bottles. The hot bottle is similar to the cold bottle in the forming process. It is classified into a heat bottle and can be heat resistant to 85 ° C or higher Cold bottles do not require heat resistance. The tea beverage bottle is a modified PET bottle blended with polyethylene naphthalate (PEN) or a composite bottle of PET and thermoplastic polyarylate. PET blow molding bottles can be divided into two categories, one is a pressure bottle, such as a bottle filled with carbonated carbonated beverage the other is a pressureless bottle, such as a bottle filled with water, tea, edible oil, and the like. In the two molding methods, the injection-blowing process is easy to control, the production efficiency is high, and the waste products are less and more common. The production of PET plastic bottles can be divided into injection stretch blow molding (abbreviated as injection blow) and extrusion stretch blow molding according to preform preforming. Polyethylene terephthalate (PET) is abbreviated as polyester.
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