The shrinkage rate of self sealing bag in the blocked direction is always smaller than that in the unimpeded direction, and the shrinkage near the insert is less than that far away from the insert. The shrinkage of simple shape products is less than that of complex products. There are also obvious differences between the flow direction of self sealing bag and that perpendicular to the flow direction. Generally, the shrinkage rate in the flow direction is greater than that in the vertical direction. The factors influencing the shrinkage of self sealing bags are described in detail below.

其次要说的是提高自封袋模具温度，一般会使收缩率增大，特别是对于结晶型塑料。延长保压时间，可以使收缩率减小。但是一旦浇口已经封闭，再延长保压时间便不再会对收缩率有影响。

The second thing to say is to increase the temperature of self sealing bag mold, which will increase the shrinkage rate, especially for crystalline plastics. The shrinkage can be reduced by prolonging the holding time. However, once the gate has been closed, the shrinkage will no longer be affected by extending the holding time.

后还有一点就是提高压力可以导致塑料自封袋密度增加，使收缩率减小。提高物料温度，会使制品体积膨胀而佼压入型腔的物料减少，使收缩率增大；但物料温度的升高会使粘度减小，却有利于向型腔内传递压力，又使收缩率减小，终收缩率的大小取决于这上述两种效应的综合影响。一般粘度对温度变化敏感的塑料，后一种效应影响大，致使收缩率减小：粘度对温度变化不敏感的塑料，前一种效应影响大，导致收缩率增大。

After another point is that increasing the pressure can lead to the increase of the density of the plastic self sealing bag and reduce the shrinkage rate. Increasing the material temperature will make the product volume expand and reduce the material pressing into the cavity, which will increase the shrinkage rate; however, the increase of material temperature will reduce the viscosity, which is conducive to transfer pressure to the cavity and reduce the shrinkage rate. The final shrinkage rate depends on the comprehensive influence of the above two effects. In general, the latter effect has a great influence on the shrinkage of plastics which is sensitive to temperature change, which leads to the decrease of shrinkage rate; for the plastics whose viscosity is not sensitive to temperature change, the former effect has a great influence, leading to the increase of shrinkage rate.

以上就是济南自封袋的相关介绍，更多的相关知识请关注公司网站：http://www.sxsuliao.com，我们会定期更新更多的相关知识.。

The above is the introduction of Jinan self sealing bag. For more relevant knowledge, please pay attention to the company's website: http://www.sxsuliao.com We will update more relevant knowledge regularly.