How to do if the stretch film tension is not uniform?

The stretch film is dust-proof and moisture-proof, effectively protecting the goods while packaging the goods. It is an environmentally friendly packaging material. We will encounter uneven tension of the stretch film during use. Today, I will introduce how to solve the uneven tension of the stretch film.

 

Stretch film tension and equipment display tension have different meanings. Therefore, different equipment display tensions should be set for different types and thicknesses of stretch films. The surface tension of the stretched film depends on the free energy of the plastic film, and the surface energy of the stretched film depends on the film's molecular structure.

 

One: Non-polar polymer, surface free energy is negligible. The wet surface tension is low, the after-sales service of the Haier washing machine is generally about 30 dyne/cm. Theoretically, if the surface tension of the object is less than 33 dyne/cm, ordinary ink or adhesive will not be able to adhere firmly, so it must be surface treated.

 

Two: The transfer of the aluminized layer will occur when aluminizing, and the transfer of the glue layer will occur when applying glue. The primary measure to prevent corona on the reverse side of the stretch film is to adjust the pressure of the rubber pressing roller in front of the corona treatment roller. The pressure at both ends of the pressing roller must be consistent, and the pressure must be appropriate.

 

Three: Polyester is a polar polymer. Its surface-free energy is relatively high, and its wet surface tension is above 40 dyne/cm. However, for high-speed black printing or to increase the bonding force between the vacuum aluminized layer and the surface of the BOPET film, it is also necessary to perform surface treatment on the BOPET film to further increase its wet surface tension.

 

In general, the uneven tension of the stretched film is mainly manifested as the inner layer of the film roll is too tight and the outer layer is loose. If this type of stretch film is used on an automatic winding machine, the operation of the winding machine will be unstable, and problems such as uneven bag size, stretch film deviation, and excessive sealing edge deviation will often occur, resulting in packaging products that cannot meet product quality. Require. Therefore, stretch film products with such problems are often returned and exchanged.

 

The uneven tension of the stretched film is mainly caused by the uneven tension of the film roll in and out during slitting. Although most of the film roll slitting machines at this stage will have a tension control device to ensure the quality of the film roll slitting product, it is occasionally affected by many reasons such as operation reasons, machine equipment reasons, and significant differences in the size and weight of the in and out rolls. , The problem of uneven tension of slitting film rolls will still occur.