After injection molding of modified plastic products, defects of small volume or clusters of pores will be formed inside. The main reason for the generation of bubbles in modified plastic products is that the gas enters the donor and is obtained by cooling and molding with the melt, resulting in The reason for the dark bubbles is that when the plastic parts are cooled and solidified, due to the different cooling speeds inside and outside the plastic parts, the outer layer is fast and the inner layer is slow, the outer layer solidifies first, and the inner melt shrinks after cooling. This is the vacuum hole inside the modified plastic product. Form dark bubbles.

There are many reasons for the generation of air bubbles in modified plastic products, such as too low injection pressure, too fast speed, too short time and cycle, too much or too little feeding amount, insufficient pressure holding, uneven cooling or insufficient cooling, and material temperature And improper control of mold temperature will cause bubbles in the modified plastic products. After more than 20 years of business accumulation, Zhongxin Huamei Company will first analyze the specific reasons as follows:

When controlling the temperature of the mold and the melt, it should be noted that the temperature should not be too high, otherwise the melt will depolymerize and decompose, resulting in a large amount of gas or excessive shrinkage, forming bubbles or shrinkage holes; if the temperature is too low, it will cause charging pressure. If it is not enough, it is easy to generate voids inside the modified plastic parts and form air bubbles.

Under normal circumstances, the melt temperature should be controlled slightly lower, and the mold temperature should be controlled slightly higher. Under such process conditions, it is not easy to generate a large amount of gas, and it is not easy to generate shrinkage holes. When controlling the temperature of the barrel, the temperature of the feeding section should not be too high, otherwise it will produce backflow and cause bubbles.

If the exhaust system of the mold is blocked, the gas is mixed into the melt, resulting in the generation of bubbles. In this regard, the exhaust system of the mold should be carefully checked to clear the blocked channel.

If the flow is too long or too thin, or if there is a dead space for gas storage in the runner, it will cause poor exhaust of the mold. For this, the narrow runner should be shortened and widened, and there should be no dead corners in the runner.

If the moisture content in the raw materials is too high, or the volatile components exceed the standard, they will generate a lot of gas after being subjected to people, which will add extra burden to the exhaust system of the mold. If they cannot be discharged in time, they will be mixed into the melt and form bubbles. Therefore, these raw materials should be pre-dried.

If the particle size of the raw material is too small, the particle size difference is large, so that too much air is mixed in the feeding process, the chance of gas entering the melt increases, and it is easy to generate air bubbles.