PET plastic bottle production process

The production process of PET plastic bottles is popularized by health care product plastic bottle manufacturers:

1, plastic processing

Because the PET plastic bottle contains a lipid group and has a certain hydrophilicity, the pellet is sensitive to water at high temperature. When the moisture content exceeds the limit, the molecular weight of the PET plastic bottle decreases during processing, and the product is colored and changed. brittle. In this case, the material must be dried before processing, and the drying temperature is 150 ° C, 4 hours or more, generally 170 ° C, 3-4 hours. The airborne method can be used to check whether the material is completely dry. When using the materials, the raw materials should be dried to a certain extent. Pay attention to different drying temperatures and time limits to ensure that the produced plastic bottles have good product functions.

2, injection molding machine selection

PET plastic bottles have a low melting point after melting point, and the melting point is higher. Therefore, it is necessary to use an injection system with more temperature control sections and less self-friction heat during plasticization, and the actual weight of the product (aqueous mouth material) cannot be used. Less than 2/3 of the machine's injection volume.

3, residence time

Do not use excessive residence times to prevent molecular weight degradation. Try to avoid temperatures above 300 °C. If the shutdown is less than 15 minutes. Only need to be air-blasted; if it is more than 15 minutes, clean it with viscosity PE and reduce the temperature of the barrel to PE temperature until it is turned on again. Strict control should be carried out when the plastic bottle is used for residence time. The treatment to be carried out at different temperatures is different, and the time limit must be strictly controlled.

4, pay attention to matters

Recycled materials should not be too large, otherwise it will easily cause "bridge" at the blanking and affect plasticization. When recycling plastics, the number of recycled materials should be strictly controlled to ensure the plasticizing quality of plastics. If the mold temperature is not well controlled or the material temperature is not properly controlled, it is easy to produce "white fog" and is opaque. Strict control of the mold temperature is required, otherwise events that do not want to be seen will occur, the mold temperature is low and average, the cooling rate is fast, and the product is less transparent when the crystal is less.

5, mold and gate design

PET plastic preforms are generally formed by hot runner molds. It is better to have heat insulation panels between the mold and the injection molding machine template. The thickness is about 12 mm, and the heat insulation panels must withstand high pressure. Exhaust gas must be sufficient to avoid local overheating or chipping, but the depth of the exhaust port should not exceed 0.03mm, otherwise it will easily produce flash. The production process of PET plastic bottles requires strict quality system maintenance to ensure that the produced plastic bottles have good product quality and guarantee. The production process is complex and requires different production processes to be strictly controlled to ensure that each process is carried out in strict accordance with the scale.