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

原材料是鋁箔袋粘合層的載體，材質質量不好或者不合適，會嚴重影響熱封強度。一方面是原鋁箔的表面油污，會削弱粘合劑與原鋁箔之間的粘接力。另一方面，熱封強度還與原鋁箔的金屬成分及表面光度不夠都影響熱封強度。鋁箔袋生產(chǎn)選用的不同包裝材料，在實際生產(chǎn)時需要的熱封參數(shù)也大不相同，務必要結合實際生產(chǎn)需要、產(chǎn)品包裝性能要求，切實可靠地調整熱封參數(shù)。

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、粘合劑

2、 Adhesive

粘合劑方面一粘合劑是含有溶劑的特殊物質，它在一定工藝條件下涂布在原鋁箔的暗面，經(jīng)過烘道烘干形成粘合層，對產(chǎn)品的熱封強度起著決定性作用。

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，除了控制粘合劑質量之外，也要注意涂布速度和控制烘道溫度。如果涂布速度過快，烘道溫度過高，會使涂膜表面溶劑揮發(fā)過快,造成膜內(nèi)溶劑的殘余，涂膜干燥就不夠充分，這樣就會影響產(chǎn)品的熱封強度。

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、冷卻過程

3、 Cooling process

鋁箔袋熱封后的冷卻過程也需留神，當用較低溫度對剛剛熔融熱封后的焊縫進行定型時，有可能會因為冷卻不良也會導致鋁箔袋熱封強度降低，還會影響焊縫的外觀平整程度，出現(xiàn)不合格品。一般的，鋁箔袋冷卻不良多有可能是因為熱封壓力不夠、冷卻水循環(huán)不暢、水溫太高或冷卻不及時等造成。

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、熱封條件

4、 Heat sealing conditions

熱封溫度是影響熱封強度的重要因素。溫度太地的話，粘合層與pvc膠片之間的粘接便不牢固。如果溫度太高，又會使藥品受影響。所以，合理的熱封溫度一般為150°C~160^C之間。

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.

要想達到理想的熱封強度，就需要設置一定的熱封壓力。如果壓力不足，就不能使鋁箔袋品的黏合層與pvc膠片充分貼合熱封，因此不能達到良好的熱封效果。

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.

熱封時間也會影響熱封強度。一般情況下，在相同的熱封溫度與壓力下，長一點的熱封時間可以使熱封部位封合得更加牢固完善。能更好地達到預期的熱封強度。如果熱封時間太短，就會使黏合層與pvc膠片之間熱封不充分。為此，標準規(guī)定了科學的熱封時間為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、盛放產(chǎn)品

5、 Holding products

鋁箔袋需要盛裝的產(chǎn)品同樣會影響鋁箔袋的熱封強度。譬如，當鋁箔袋用于包裝細小粉末狀產(chǎn)品時，容易在盛裝時沾在鋁箔袋封口處，此時就需要合理根據(jù)包裝的產(chǎn)品調整生產(chǎn)所需的包裝材料和鋁箔袋內(nèi)層材料厚度，以此保證并提高鋁箔袋的熱封強度。

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.