A plastic bottle is a plastic container that takes PET, PE and PP as raw materials, adds the corresponding organic solvent, is heated at high temperature, and then blows, extruded or even injection molded. Plastic bottles are not easy to break, low cost, high transparency, food grade materials, etc. But bubbles often appear in the production of biobased white knives, what causes them? The following Xiaobian will tell you about it.

First, material factors

1. Raw materials contain water.

2. Mold factor

3, the mold is trapped in the air, so the mold should be maintained or the exhaust tank should be added

Ii. Technical factors:

1, the speed is too fast, so that the molten plastic is decomposed under the action of large shear, producing gas.

2, the local cooling of the product is too fast, and the contraction is uneven. Especially when the wall thickness of the product is large, the surface cooling rate is faster than the central part. During the cooling process, the plastic in the center part contracts and expands outwards, making the center part inadequately filled and forming a vacuum bubble.

3, the lack of pressure and pressure retention makes the melt not close to the surface of the cavity, which is not conducive to exhaust.

4, insufficient back pressure, control the backward speed of the screw. When the back pressure is small, the screw backward speed is faster, which is easy to lead to insufficient feed. More air is brought into the material, and it is too late to discharge from the feed port, resulting in a large number of bubbles.

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