The main functions of self sealing bag include four aspects: ① convenient use, transportation, management and storage; ② Improve the grade of commodities; ③ High reuse rate, reduce plastic waste and protect resources. The above four points make the self sealing bag in short supply in the market. After a large amount of demand, there is a large number of non-standard production, and the shrinkage rate of self sealing bag is an embodiment. Without good technology and equipment, most of the self sealing bags produced have this problem.

自封袋自身结构的影响：

Influence of self sealing bag on its own structure:

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 less than that of the part with larger wall thickness, the shrinkage rate of the part away from the insert is greater than that of the part close to the insert, and the shrinkage rate perpendicular to the flow direction is also different. Generally, the shrinkage rate in the flow direction is greater than that perpendicular to the flow direction, The shrinkage rate of self sealing bag in the blocked direction is smaller than that in the unimpeded direction.

原材料对自封袋收缩率的影响：

Effect of raw materials on shrinkage of self sealing bags:

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 greater than that of amorphous plastics, the molding shrinkage rate of plastics with poor fluidity is large, and the molding shrinkage rate of plastics with good fluidity is small, If the filler is added to the plastic, the shrinkage of the formed plastic will be significantly reduced, and the shrinkage of the plastic without filler will be better.

压力和温度对自封袋收缩率的影响：

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，使得收缩率加大，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 producing the self sealing bag is increased, the volume of the self sealing bag will expand, and the materials entering the mold through the pressure will become less, which will increase the shrinkage rate. However, the increase of the temperature of the raw materials will reduce the viscosity, and the decrease of the viscosity will increase the pressure in the mold cavity, The shrinkage rate of self sealing bag is reduced, so the factors that will eventually affect the shrinkage rate of self sealing bag depend on the combined influence of pressure and raw material temperature.

了解了自封袋收缩率不合格的原因之后，我们以后再挑选自封袋的时候一定要选择规格标准的，一些残次品虽然便宜，但是使用起来不方便，有时候还会影响食品的质量，那就得不偿失了。

After understanding the reasons for the unqualified shrinkage rate of self sealing bags, we must choose the specifications and standards when selecting self sealing bags in the future. Although some defective products are cheap, they are inconvenient to use and sometimes affect the quality of food, so the gain is not worth the loss.

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The above is Jinan self sealing bag //www.haaimobile.com Thank you for checking the information of our company in your busy schedule. If you want to know more, you are welcome to inquire!