What are the common problems in heat sealing of stretched film? Shenzhen plastic film specifications

1. What is the effect of heat sealing temperature of stretched film on heat sealing strength?

The heat sealing temperature of stretched film has a great influence on the heat sealing strength, and the thickness of stretched film in the heat sealing layer of stretched film plays a decisive role in the heat sealing effect.

(1) When the temperature is low, the surface of the heat sealing layer melts, and the thickness of the stretched film participating in the heat sealing is thin, resulting in a low contact temperature.

② When the temperature is too high, the stretched film of the heat-sealing layer may melt completely or the heat-sealing layer may peel off the base layer, which will lead to the participation of the base layers of the upper and lower stretched films in heat sealing, which will inevitably lead to the decrease of heat-sealing strength. Therefore, when we heat-seal the stretched film, we must choose a suitable heat-sealing temperature, neither too high nor too low.

2. What is the effect of heat sealing time of stretched film on heat sealing?

The heat sealing time of automatic packaging machine or old bag-making machine is determined by the machine speed. When the heat sealing temperature and pressure are constant, the longer the heat sealing time, the stronger the bonding between heat sealing layers. However, if the heat sealing time is too long, the heat sealing part of the composite stretched film will wrinkle and be uneven, which will seriously affect the appearance quality of the product.

3. What is the effect of heat sealing pressure of stretched film on heat sealing?

In order to ensure the heat sealing strength of plastic composite soft packaging, a certain heat sealing pressure is essential. Therefore, the heat sealing pressure is required to be moderate and uniform in the heat sealing process. If the heat sealing pressure is insufficient or uneven, bubbles will be generated in the heat sealing part, resulting in poor heat sealing. If the heat sealing pressure is too high, the heat sealing part will be deformed, and when the heat sealing temperature is high, some composite materials will be extruded, which will cause the heat sealing edge to be brittle and easy to crack, and at the same time lead to the decrease of heat sealing strength.

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