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The production process and technology of PET bottles

Jun 25, 2018

Production technology of plastic bottles, the rheological properties of PET plastic bottles in the molten state, stress on the influence of the viscosity is bigger than the temperature, therefore, mainly from the pressure begin to change the melt liquid plastic bottle in different environments have different state of use, so under the molten state of plastic bottles for effective control of rheology and viscosity.

1 injection molding machine selection of PET plastic bottle since the stable time is short, after melting point and melting point is high, so need more plasticizing temperature control paragraph from the friction heat generating less injection system, and real weight products (water cut materials) can not be less than two-thirds of the injection molding machine selection of injection machine needs to be based on injection molding machine and reasonable control injection system, based on these requirements, our country in recent years, the development of small and medium-sized series of PET special plasticizing system, the clamping force by more than 6300 t/m2

 2 plastic processing Because the PET plastic bottle macromolecule containing aliphatic, has certain hydrophilicity, aggregate at high temperature is more sensitive to water, when the moisture content is more than the limit, in the processing of PET plastic bottle molecular weight decreased, crisp trapped the products with color, must be to dry the material before processing, the drying temperature was $150, more than 4 hours, generally is 170, 3-4 hours Air-launched available to test whether the material completely dry Materials used for raw material must be dry, pay attention to the different drying temperature and time limits, ensure the production of plastic bottles with good product performanceGenerally, the proportion of recycled materials should not exceed 25%, and the recycled materials should be thoroughly dried

3. Do not use too long retention time to prevent the molecular weight from falling, and try to avoid the temperature above 300.If more than 15 minutes, then use PE clean, viscosity and the barrel temperature drop to PE, until it is in the residence time of plastic bottles must carry on the strict control, need to undertake the processing of different in different temperature, must be strictly grasp the time constraints

4 mould and PET plastic bottle embryo gate design general use molding mould of hot flow path, between the mold and injection molding machine template must have the best insulation board, its thickness is about 12 mm, and the heat shield must be able to bear high pressure exhaust must be sufficient, lest appear local overheating or broken, but the depth of the vent generally not more than 0.03 mm, otherwise prone to flash

5 The lower the back pressure is, the better, so as to avoid wear and tear

6. Generally, the injection speed is faster, which can prevent premature solidification but too fast during the injection. The high shear rate makes the material fragile and the injection material is usually completed within 4 seconds

7 note recycling material cannot too big, otherwise easy to produce the next where the "bridge" and affect the plasticizing, in plastic recycling, strictly control the amount of recycled materials, ensure the quality of plastic plasticizing if mold temperature control is not good or improper material temperature control, easy to produce "white mist and opaque to calibrate mould strict control, can appear otherwise don't want to see the events, die temperature is low and uniform, cooling speed, production technology of crystal products are less transparent plastic test requires strict quality system, ensure the production of plastic bottles with good product quality and guarantee
The production process is complex and requires strict control of different production processes to ensure that each process is carried out in strict accordance with the standards