Aluminum foil bags are a common material in food packaging, with advantages such as good mechanical properties, long storage time, and preservation and fragrance, which are deeply loved by consumers. The heat sealing strength is one of the important indicators to measure the quality of aluminum foil bags. If there is a problem with the heat sealing strength, it is likely to cause bag breakage and affect product quality. Today, starting from the factors that affect the heat sealing strength, we will analyze how to ensure the heat sealing strength of aluminum foil bags.

一、原材料

1、 Raw materials

原材料是铝箔袋粘合层的载体，材质质量不好或者不合适，会严重影响热封强度。一方面是原铝箔的表面油污，会削弱粘合剂与原铝箔之间的粘接力。另一方面，热封强度还与原铝箔的金属成分及表面光度不够都影响热封强度。铝箔袋生产选用的不同包装材料，在实际生产时需要的热封参数也大不相同，务必要结合实际生产需要、产品包装性能要求，切实可靠地调整热封参数。

The raw material is the carrier of the adhesive layer of the aluminum foil bag, and poor or inappropriate material quality can seriously affect the heat sealing strength. On the one hand, the surface oil stains of the original aluminum foil can weaken the bonding force between the adhesive and the original aluminum foil. On the other hand, the heat sealing strength is also affected by the insufficient metal composition and surface brightness of the original aluminum foil. The different packaging materials used in the production of aluminum foil bags also require different heat sealing parameters in actual production. It is necessary to adjust the heat sealing parameters in a practical and reliable manner based on actual production needs and product packaging performance requirements.

二、粘合剂

2、 Adhesive

粘合剂方面一粘合剂是含有溶剂的特殊物质，它在一定工艺条件下涂布在原铝箔的暗面，经过烘道烘干形成粘合层，对产品的热封强度起着决定性作用。

In terms of adhesive, adhesive is a special substance containing solvents. It is coated on the dark surface of the original aluminum foil under certain process conditions, and then dried through a drying channel to form an adhesive layer, which plays a decisive role in the heat sealing strength of the product.

因此，除了控制粘合剂质量之外，也要注意涂布速度和控制烘道温度。如果涂布速度过快，烘道温度过高，会使涂膜表面溶剂挥发过快,造成膜内溶剂的残余，涂膜干燥就不够充分，这样就会影响产品的热封强度。

Therefore, in addition to controlling the quality of the adhesive, attention should also be paid to the coating speed and controlling the drying temperature. If the coating speed is too fast and the drying temperature is too high, it will cause the solvent on the surface of the coating film to evaporate too quickly, resulting in residual solvent inside the film. The drying of the coating film will not be sufficient, which will affect the heat sealing strength of the product.

三、冷却过程

3、 Cooling process

铝箔袋热封后的冷却过程也需留神，当用较低温度对刚刚熔融热封后的焊缝进行定型时，有可能会因为冷却不良也会导致铝箔袋热封强度降低，还会影响焊缝的外观平整程度，出现不合格品。一般的，铝箔袋冷却不良多有可能是因为热封压力不够、冷却水循环不畅、水温太高或冷却不及时等造成。

Attention should also be paid to the cooling process of aluminum foil bags after heat sealing. When using a lower temperature to shape the weld seam that has just been melted and heat sealed, it is possible that poor cooling can also lead to a decrease in the heat sealing strength of the aluminum foil bag, and it can also affect the appearance flatness of the weld seam, resulting in unqualified products. Generally, poor cooling of aluminum foil bags may be caused by insufficient heat sealing pressure, poor cooling water circulation, high water temperature, or delayed cooling.

四、热封条件

4、 Heat sealing conditions

热封温度是影响热封强度的重要因素。温度太地的话，粘合层与pvc胶片之间的粘接便不牢固。如果温度太高，又会使药品受影响。所以，合理的热封温度一般为150°C~160^C之间。

The heat sealing temperature is an important factor affecting the strength of the heat sealing. If the temperature is too low, the bonding between the adhesive layer and the PVC film will not be firm. If the temperature is too high, it can also affect the medication. Therefore, the reasonable heat sealing temperature is generally 150° Between C~160 ^ C.

要想达到理想的热封强度，就需要设置一定的热封压力。如果压力不足，就不能使铝箔袋品的黏合层与pvc胶片充分贴合热封，因此不能达到良好的热封效果。

To achieve the ideal heat sealing strength, it is necessary to set a certain heat sealing pressure. If the pressure is insufficient, the adhesive layer of the aluminum foil bag cannot fully adhere to the PVC film for heat sealing, therefore, a good heat sealing effect cannot be achieved.

热封时间也会影响热封强度。一般情况下，在相同的热封温度与压力下，长一点的热封时间可以使热封部位封合得更加牢固完善。能更好地达到预期的热封强度。如果热封时间太短，就会使黏合层与pvc胶片之间热封不充分。为此，标准规定了科学的热封时间为1s。

The heat sealing time also affects the heat sealing strength. In general, under the same heat sealing temperature and pressure, a longer heat sealing time can make the heat sealing part seal more firmly and perfectly. Can better achieve the expected heat sealing strength. If the heat sealing time is too short, it will cause insufficient heat sealing between the adhesive layer and the PVC film. Therefore, the national standard stipulates a scientific heat sealing time of 1 second.

五、盛放产品

5、 Holding products

铝箔袋需要盛装的产品同样会影响铝箔袋的热封强度。譬如，当铝箔袋用于包装细小粉末状产品时，容易在盛装时沾在铝箔袋封口处，此时就需要合理根据包装的产品调整生产所需的包装材料和铝箔袋内层材料厚度，以此保证并提高铝箔袋的热封强度。

The products that need to be contained in aluminum foil bags can also affect the heat sealing strength of the bags. For example, when aluminum foil bags are used to package small powder products, they are prone to getting stuck at the sealing area of the aluminum foil bag during packaging. Therefore, it is necessary to adjust the packaging materials and inner layer material thickness required for production according to the packaged products, in order to ensure and improve the heat sealing strength of the aluminum foil bag.