Solving Common Issues with PEF Shrink Film for Ideal packaging

As a versatile and efficient enco-friendly solution, Pef Shrink Film is widely used in the outer packaging of various products. Compared with POF and cross-linked film, PEF film has unique shrinkage characteristics. Therefore, when using PEF film for shrink packaging and encountering problems such as fogging, poor sealing, and large shrinkage corners, we need to make targeted adjustments and adjust the settings of the packaging machine to achieve the ideal shrinkage effect.

1.Fogging

Fogging is one of the common problems in the shrinking process of PEF film, which is manifested as the surface of the shrink film becomeing blurred, as if covered with a layer of white fog. This is mainly due to the change in the material structure of the film itself at high temperature. The suitable temperature range for PEF film is 135-145℃. When the temperature exceeds 145℃, fogging may occur on the membrane surface.

 Schematic diagram of fogging on the film surface

Therefore, when we encounter fogging on the film surface, we should first check the shrinking temperature setting of the packaging machine. If the temperature is too high, it should be appropriately lowered. It is recommended to set the shrinking temperature at around 140℃. In addition, increasing the number of exhaust vents can effectively prevent gas stagnation, thereby reducing the occurrence of fogging. At the same time, appropriately speeding up the operation speed of the shrinking furnace and shortening the heating time of the shrinking film are also effective ways to solve the fogging problem.

2.poor sealing performance

 Schematic diagram of seal damage

Poor sealing performance is manifested by damaged sealing lines or small holes, which directly affects the sealing and aesthetics of the package. To improve the sealing performance, we first need to pay attention to the setting of the hot knife of the seal bar temperature.

If the hot knife temperature is too low, the seal may be loose or even sticky; if it is too high, the sealing line will be burned and the seal will be damaged. Therefore, when using PEF film for shrink packaging, it is recommended to adjust the hot knife temperature to 205-210℃ to ensure that the seal can be effectively cut and not easily damaged.

In addition to the hot knife temperature, the number of exhaust vents and the operating speed of the shrink furnace are also important factors affecting the sealing performance. Properly increasing the number of exhaust vents can prevent the shrink film from breaking the seal due to excessive expansion during the heating process. At the same time, speeding up the operating of the shrink furnace can reduce the seal rupture caused by long-term heating of the shrink film.

3.large shrinkage corners

Large shrinkage corners are another common problem in the shrinkage process of PEF film. Although PEF film has a high shrinkage rate, improper operation can still lead to large corners.

Schematic diagram of large corner

First of all, we need to make sure that the size of the packaging bag is appropriate. If the packaging bag is too large, it may not fit properly, while if it is too small, it may shrink unevenly. Therefore, when choosing a packaging bag, it should be reasonably set according to the shape and size of the packaging.

Secondly, check whether the shrinking temperature is too low. If the temperature is too low, the corners may not be able to expand and shrink sufficiently. At this time, the shrinking temperature can be appropriately increased to ensure that the corners can also achieve the ideal shrinking effect.

Finally, if the corners are still too large after the above adjustments, we can further optimize by adjusting the number of vents and the shrink furnace speed. The specific method is to reduce the number of exhaust vents and appropriately slow down the speed of the shrink furnace so that the film has enough time to fully expand in the shrinking furnace, thereby achieving a tight-fitting shrinking effect.