The heat sealing performance of the packaging material is the main index for evaluating the packaging performance of the material, including hot tack and heat sealing strength. Hot Tack, and Ultimate Strength is the peeling strength after the heat sealing part is completely cooled. These two indicators of the same material are very different. However, in fact, the good application of these two indicators is often directly related to the selection of packaging materials and the actual filling efficiency.

1. Application of thermal adhesive force

Today, most flexible packaging fillings in the food, pharmaceutical, cosmetic, and other fields use a Form-Fill-Seal Machine. In these filling production lines, the production process of the flexible packaging bag and the filling process are carried out at the same time, and the product filling method is basically that the product falls into the packaging bag from a certain height and has a strong impact on the bottom of the packaging bag. If the bottom of the bag cannot withstand the impact force, the bottom will crack. The broken bag will not only affect the cleanliness of the production environment, but also affect the filling efficiency. Since the interval between the two-step operations of heat-sealing bag-making and content filling on the filling production line is very short, it is impossible to completely cool the heat-sealed part of the packaging bag within such a short time interval. The heat seal strength is not suitable for the evaluation of the heat seal performance of the material here, and the hot tack force of the material should be used. Suzhou Export Hazardous Packing Box has been generally recognized to optimize the heat sealing procedure during the packaging process as an effective way to shorten the packaging cycle time, and the thermal adhesion test can help operators choose the most optimal heat sealing parameters.

Therefore, the difference between the application of hot tack and heat sealing strength is very clear. The hot tack performance is used to ensure the normal operation of the filling production line, and its suitability directly affects the filling efficiency and bag break rate; while the heat sealing performance It is mainly used to evaluate the storage performance of materials, and to ensure that the heat-sealed part will not leak during transportation, storage, and display, which is the premise to realize the functionality of packaging materials.

2. Case study

How to choose the best production line heat sealing parameters for the packaging of dangerous goods in Suzhou by testing the heat adhesion of the material? The following takes the customer test commission accepted by Labthink laboratory as an example to introduce the relationship between the heat adhesion and the selection of heat sealing parameters for the production line.

The customer is a food production company in Southeast Asia, and wants to choose one of the two types of films A and B with similar performance indicators, which not only meets the bag making requirements of the production line, but also makes the production line have high filling efficiency. Affected by other factors, the hot tack time and heat sealing pressure that the production line can provide has been determined, and the heat cover of the material is also determined. The customer requires that the heat sealing temperature of the packaging material is not higher than 133°C, and the hot adhesive force is not lower than 2N.

We use Labthink HTT-L1 thermal adhesion tensile tester to test the thermal adhesion of A and B films. The heat sealing time is set to 0.3s, 0.5s, 0.7s, and the heat sealing temperature is 121°C, 124°C, 127°C, 130°C, 133°C, other indicators are set according to customer requirements, and the width of the test sample is 25mm according to customer requirements.