简单的热封方法手工热封法：常用于PE、PP单一薄膜热封。

Simple heat sealing method: manual heat sealing method: commonly used for PE and PP single film heat sealing.

热封时需要借助于耐热薄膜将普通电烙铁刀口部位弯成“L”形，刀口宽度一般为3mm，再将导线接通在调压器上进行恒温控制。薄膜在封口处留一个边，则热封强度会更大些。实际操作时，铺2层细平布，再铺一层不易变形的卡其布，布纹应与热封线呈45°或平直，其作用是使热封部位产生均匀的花纹，以强化花纹(起到筋骨支撑的作用)结构来达到分子间互相渗透的目的，提高封口界面的密封性。

During heat sealing, it is necessary to bend the knife edge of ordinary electric soldering iron into "L" shape with the help of heat-resistant film, the width of the knife edge is generally 3mm, and then connect the wire to the voltage regulator for constant temperature control. If the film leaves an edge at the seal, the heat sealing strength will be greater. During actual operation, lay two layers of fine plain cloth, and then lay a layer of non-deformable khaki cloth. The cloth pattern should be 45 ° or straight with the heat sealing line. Its function is to make the heat sealing part produce uniform patterns, so as to strengthen the pattern (play the role of rib support) structure to achieve the purpose of mutual penetration between molecules and improve the sealing of the sealing interface.

依靠外部加热实现热封的热板热封法：先将两层重叠的薄膜放在两块加热(或者其中一块加热)的金属板之间，直到表层熔化，然后在压力下使熔化的表面迅速结合在一起，并保持压力冷却为止。热板热封装置结构简单，成本低，寿命长，且不易损坏。

Hot plate heat sealing method relying on external heating: first place two overlapping films between two heated (or one heated) metal plates until the surface layer melts, and then quickly combine the melted surfaces under pressure and keep the pressure until cooling. The hot plate heat sealing device has simple structure, low cost, long service life and is not easy to be damaged.

此外，还有一种热空气热封法，这种方法就是借助热气，将其吹向塑料薄膜表面进行热封，此法可应用于重包装的热封。

In addition, there is also a hot air heat sealing method. This method is to use hot air to blow it to the surface of plastic film for heat sealing. This method can be applied to the heat sealing of heavy packaging.

人们在选购塑料包装袋的时候，许多人会下意识的挑选厚而牢固的包装袋，并且人们一般觉得越厚的包装袋品质越高，可是事实上并非越厚越牢固的包装袋越高。由于对塑料包装袋的制做规定是有很严苛的规范的，非常是用在食品包装上的塑料袋，是一定要采用靠谱生产厂家所生产的，会有有关部门开展审核的合格工艺品。

When people buy plastic packaging bags, many people will subconsciously choose thick and strong packaging bags, and people generally think that the thicker the packaging bags, the higher the quality, but in fact, the thicker and stronger the packaging bags, the higher the quality. Because the state has strict regulations on the production of plastic packaging bags, especially plastic bags used in food packaging, must be produced by reliable manufacturers, and will be reviewed by relevant departments.

食品用的塑料袋务必标明有“食品专用型”和“QS标示”这类的标字。此外，可以冲着光源能够看见塑料袋是不是整洁。由于合格的胶袋是很整洁、没有杂质的，殊不知伪劣的塑料袋就会见到有脏点、杂质。这都是人们平时在选购时能够直观分辨塑料袋品质的一种好方式呢。

The plastic bags used for food must be marked with "food special type" and "QS mark". In addition, you can see whether the plastic bag is clean by looking at the light source. As the qualified plastic bags are clean and free of impurities, it is hardly surprising that the fake and inferior plastic bags will have dirty spots and impurities. This is a good way for people to visually distinguish the quality of plastic bags when shopping.