Injection Molding of PET Bottle Embryo

PET bottles are widely used in daily necessities, daily chemical packaging, and other fields because of their strong applicability. PET bottle is first formed into bottle embryo through injection molding, and then into PET plastic bottle through blow molding. The quality of a PET bottle depends on the quality of the bottle embryo supplied, so the injection molding process of the PET bottle embryo is particularly important.

Due to the short stabilization time of PET material after the melting point and the high melting point. It is necessary to select an injection system with more temperature control sections and less self-friction heat generation during plasticizing. The actual weight of the product should not be less than 2/3 of the injection amount of the machine.

The screw design of the PET bottle embryo is very important to the bottle embryo injection molding process.

The general screw used for PET injection is of poor quality and easy to causes problems. Therefore, the PET injection machine must have a special screw. As PET is a heat-sensitive material, it is easy to break the molecular chain at high temperatures, reduce molecular weight, produce acetaldehyde, and reduce the quality of the bottle embryo. In the material pipe, the screw is mainly used to rotate and compress to make the ester particles produce shear heat and melt. If the shear heat generated by screw compression is too large, PET thermal cracking may occur. Therefore, the PET injection screw must be designed with low shear and can melt the crystalline PET ester particles. Too high a compression ratio or too short a compression length will cause large shear. However, the shear heat generated by the screw with too low a compression ratio may not be enough to completely melt the ester particles, which may lead to the white atomization of the bottle embryo crystal. The air in the material tube cannot be completely discharged, which may easily cause bubbles in the bottle embryo.

The whole bottle embryo process equipment, in addition to PET injection molding, also includes a hot runner bottle embryo mold, ester grain dehumidifier dryer, mold cooling ice water machine, bottle embryo removal manipulator, bottle embryo conveyor belt and injection environment control air conditioning dehumidifier, etc. All machines and tools are required to cooperate with the action of the injection machine. The fit of the whole set of PET injection molding equipment determines the quality and efficiency of PET injection molding. 

Our machine can provide better energy conservation, system reliability, bottle embryo quality, and production efficiency. It can be widely used in beverages, edible oil, condiment, thin-wall, daily chemical, medicine, and other packaging fields.