Five Small Details to Improve the Heat Sealing Effect of Packaging Bags
The heat sealing strength of composite packaging bags is an important index in packaging bags, which directly relates to whether the products can be well protected.Sometimes we will encounter plastic bags with insufficient heat sealing strength, leading to air leakage, cracking and other phenomena.So how can we strengthen the heat sealing strength of the packaging bag?
First of all, let's look at what factors affect the heat seal strength of the bag: 1. the temperature, pressure and time of the heat seal knife; 2. the width and shape of the heat seal knife; 3. the material and thickness of the heat seal layer; 4. the composite strength of the material; 5. the smoothness of the surface of the heat seal layer.The above five factors are the main factors affecting the heat seal strength.If we want to improve the heat sealing strength of packaging bags, we should also start from these five aspects.
First, ensure that the surface of the heat-seal layer is bright and clean
When there are foreign matters on the surface, the heat seal strength will obviously decrease. To ensure the surface of the heat seal layer is clean, the following work should be done: a. Ensure the cleanliness of the conveyor belt and roller of automatic packaging equipment or bag making machine;B, remove sharp and hard objects on the equipment to prevent foreign matters from being generated by rubbing the film and being clamped in heat sealing;C, when the filler is powder and other articles that are easy to generate static electricity, the heat sealing layer should be made of antistatic film.
Second, adjust the heat sealing temperature, pressure and time
For heat-sealing layers of different materials and thicknesses, the optimal combination of heat-sealing temperature, pressure and time is also different. When these parameters are adjusted to the optimal combination, the heat-sealing strength is the highest.This can be consulted with suppliers or the test summary can be adjusted continuously.
Third,widen the width of the heat sealing knife or change it into a wavy surface heat sealing knife.
Widening the width of the heat-seal knife is to widen the heat-seal width, which does not actually enhance the heat-seal strength, but it can reduce the influence of tiny foreign matters such as powdery particles on the heat-seal strength.The use of wave-shaped heat-sealing knives can make the heat-sealing layers fuse better, thus improving the heat-sealing strength.
Fourth, thicken the heat-sealing layer or choose a film with better heat-sealing effect.
Thickening the heat sealing layer makes more films fuse together, which is the same as the principle of 1 chopstick and 10 chopsticks.For films made of different materials, the suction force between molecules after fusion is also different, and the suction force is also different in different environments.For example, LDPE has significantly higher heat seal strength than CPP with the same thickness in low temperature environment.
Five, improve the composite strength of the material
When the composite strength of the composite packaging bag is not enough, offset or fault occurs under the pressure of the heat sealing knife, so the pressure of the heat sealing knife on the lowest heat sealing layer will be reduced, resulting in insufficient heat sealing strength.
The above five methods are methods to improve the heat sealing strength of composite packaging bags.If the first factor does not exist, see how the second factor is doing.And so on.In addition, because more attention is paid to consumer experience, the stronger the heat seal strength of the packaging bag is not the better, especially when the packaging bag is not designed with a tear opening, the smaller the heat seal strength of the packaging bag is, and the more convenient it is for consumers to open the packaging bag, the better on the premise of ensuring product protection.