PET bottles are one of the types of packaging bottles that cosmetics often use. The cost of bottles of this material is not too high, so PET bottles are still very cost-effective for so many cosmetic container materials, and they have always been subject to the market. A lot of cosmetics brand customers love. What should you pay attention to when making such a popular bottle?
Because PET macromolecules contain a lipid group and have a certain hydrophilicity, the pellets are sensitive to water at high temperatures. When the moisture content exceeds the limit, the molecular weight of PET decreases during processing, and the finished product is colored and brittle. In this case, it is necessary to dry the material before processing, and the drying temperature is 150 ° C, more than 4 hours, generally 170 ° C, 3-4 hours. It is not completely boring to use the air-launch method to check the data. The share of the recovered material should generally not exceed 25%, and the recovered material should be completely boring.
Because PET has a short time after the melting point and the melting point is high, it is necessary to select an injection system with more temperature control sections and less self-conflict heat during plasticization, and the finished product of the cosmetic bottle manufacturer (aqueous mouth material) practice The component cannot be less than 2/3 of the machine's injection volume.
The PET preform is generally formed by a warm runner mold. There is a heat shield between the mold and the injection molding machine template. The thickness of the PET preform is about 12 mm, and the heat shield must be able to accept high pressure. Exhaust is necessary to prevent partial overheating or chipping, but the depth of the exhaust port should generally not exceed 0.03mm, otherwise the flash will occur simply.
The injection speed is fast to prevent premature solidification during the injection process. However, too fast and high shear rates make the material fragile, usually completed in 4 seconds.
More Information: PET Bottles Wholesalers
