Three factors affecting the heat seal strength of heat shrink film
With the rapid development of food, cosmetics, medicine and other industries, the demand for plastic composite packaging products is increasing, and the quality requirements for plastic composite packaging products are getting higher and higher. Packaging users not only pay attention to the beauty and logistics performance of the packaged products, but also pay attention to the heat-sealing strength of the packaged products. Because the heat seal strength of packaged products directly affects packaging performance, transportation and sales.
In actual production, each manufacturer regards heat seal strength as the most important quality index to control whether it is bag-making products or coil products used in automatic packaging production lines. Based on the experience in actual production, a simple analysis of the factors affecting the heat seal strength of the heat shrinkable film:
1. Heat sealing temperature: The heat sealing temperature directly affects the heat sealing strength of plastic composite packaging products.
2. Heat sealing time: The heat sealing time of the automatic shrink packaging machine is determined by the machine speed. When the heat-sealing temperature and heat-sealing pressure remain unchanged, the longer the heat-sealing time, the stronger the bond between the heat-sealing layers. However, if the heat-sealing time is too long, the heat-sealed part of the composite film will appear wrinkles and unevenness, which will seriously affect the appearance quality of the product.
3. Heat sealing pressure: In order to ensure the heat sealing strength of the plastic composite flexible package, the heat sealing pressure is required to be moderate and uniform during the heat sealing process. If the heat sealing pressure is not enough or uneven, air bubbles will be generated in the heat sealing part and false welding will result in poor heat sealing.