在生产自封袋的过程中，一些工序会对自封袋的收缩率造成影响，在加工生产中要特别注意，避免生产出来的自封袋不合格，下面为大家讲解几种常见的影响自封袋收缩率的因素。

In the process of producing self sealing bags, some processes will affect the shrinkage rate of self sealing bags. Special attention should be paid to avoid unqualified self sealing bags produced in the processing and production. The following will explain several common factors affecting the shrinkage rate of self sealing bags.

1、自封袋自身结构的影响：

1. The influence of self sealing bag structure was as follows

同一自封袋中，壁厚较小的部位的收缩率要小于壁厚较大的部位，远离嵌件部位的收缩率要大于靠近嵌件部位的收缩率，垂直于流动方向与流动方向的收缩率也是有差别的，一般情况下流动方向收缩率大于垂直于流动方向的收缩率，自封袋受到阻碍方向的收缩率要比无阻碍方向的收缩率要小。

In the same self sealing bag, the shrinkage rate of the part with smaller wall thickness is smaller than that of the part with larger wall thickness, the shrinkage rate of the part far away from the insert is greater than that near the insert, and the shrinkage rate perpendicular to the flow direction is also different. Generally speaking, the shrinkage rate of the flowing direction is greater than that perpendicular to the flow direction, and the shrinkage rate of the self sealing bag in the obstructed direction is higher than that in the blocking direction It is smaller than the shrinkage in the unimpeded direction.

2、原材料对自封袋收缩率的影响：

2. The effect of raw materials on the shrinkage of self sealing bag is as follows

用不同原材料生产的自封袋的收缩率也是不同的，但是使用相同材质生产的不同批次的自封袋收缩率也不相同，这主要是受到了加工生产过程的影响，结晶型的塑料的收缩率要大于无定形的塑料，流动性差的塑料成型收缩率大，流动性好的塑料成型收缩率小，如果在塑料中加入填充料会导致成型的塑料收缩率明显下降，不添加填充物的塑料生产成型后的收缩率更好。

The shrinkage rate of self sealing bags produced with different raw materials is also different, but the shrinkage rate of self sealing bags produced with the same material in different batches is also different, which is mainly affected by the processing and production process. The shrinkage rate of crystalline plastics is larger than that of amorphous plastics. The shrinkage rate of molding of plastics with poor fluidity is large, and the shrinkage rate of molding of plastics with good fluidity is small Adding fillers into plastics will lead to a significant decrease in the shrinkage of plastics, and the shrinkage of plastics without fillers will be better.

3、压力和温度对自封袋收缩率的影响：

3. Effect of pressure and temperature on shrinkage of self sealing bag:

压力过高会使得自封袋的密封增加，导致收缩率减小，如果提升生产自封袋的原材料的温度，会使得自封袋的体积膨胀，通过压力入型的物料变少，使得收缩率增大，但是原材料的温度升高会使得粘度变下，粘度变小会使得型腔内的压力增多，使得自封袋额收缩率减小，所以终会影响自封袋的收缩率的因素取决于压力和原材料温度两者的综合影响。

Too high pressure will increase the sealing of the self sealing bag and reduce the shrinkage rate. If the temperature of the raw materials for the production of the self sealing bag is increased, the volume of the self sealing bag will expand, and the amount of the material fed through the pressure will be reduced, and the shrinkage rate will be increased. However, the increase of the temperature of the raw material will cause the viscosity to decrease, and the pressure in the cavity will be reduced, which will increase the shrinkage rate of the self sealing bag Therefore, the factors that will eventually affect the shrinkage rate of self sealing bags depend on the combined effects of pressure and raw material temperature.