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Laminating Film Winding Tension
Oct 10, 2017

Laminating film Winding tension

Composite film composite process, the substrate is generally the same tension and running direction, usually divided into four kinds.

1. The first unwinding tension

The first unwinding tension is the tension between the first unwinding roll and the coating roller, and is composed of a motor, a tension sensor, a floating roller, an electric control system and the like to realize constant tension control of the substrate.

2. The second unwinding tension

The second unwinding tension is the tension between the second unwinding roll and the composite roll, and its composition is the same as the first unwinding tension.

3. Apply tension

The coating tension is generated by the difference in speed between the application roller and the composite roll. In general, the speed of the composite roll is 0.05% to 0.10% faster than that of the application roll.

The winding tension

The winding tension is the tension between the take-up reel and the compound roll, and the crimp torque is applied to the core by the clutch. Tension is applied to the outermost layer of the composite membrane by friction transmission between the coils. Taper tension is generally used for winding.

Tension in the composite film production has the following main effects:

1. The thickness of the composite film is larger than that of the outer layer, and the finished bag is curled inward. , While the composite material tension is too small, the finished bag is easier to roll out; composite process of the two composite materials to match the improper control, resulting in its aging stereotypes still have residual stress. In particular, the composite film thickness is more prone to such failure than the book, showing the outward roll; composite substrate tension is inconsistent, resulting in shrinkage curl, and which side of the large curl bias which side.

2. Composite film wrinkle: improper tension control, one of which is too large, the other is too small; film speed and coating roller speed deviation. Some models of dry laminating machine, between the coating roller and the composite roller with the stroke tension (speed ratio), the adjustment depends on the composite roller and the application of the roller between the line speed difference. If the adjustment is not easy to form a wrinkle.

3. The reason for the poor wetting of the composite film is mainly due to the fact that the anti-static agent added by the manufacturer in the process of making the film slowly soaked into the thin film surface during the storage process reduces the surface tension of the film; In addition, the corona treatment strength is insufficient or the storage time is too long during the process. The decrease of the surface tension is also the important reason for the thin film wettability.

4. Composite film peel strength is low: thin film corona treatment or heterogeneous, surface tension is low, poor wetting or excessive treatment, such as PE film surface tension below dyn / cm, will form the WBL layer (polyolefin surface molecular degradation, So that the strength of its own decline); on the ink, K coating, followed by weak, resulting in the agent on the ink, K coating with the weak reason in addition to their poor wetting (surface tension difference), the ink, K coating with The poor adhesion of the agent, the low surface tension is also important reasons, such as ink, in order to plate, the film has good wetting, often want to print its surface tension is low, but when it wants to dry its surface Tension is high, in order to facilitate the infiltration of its agent, generally should be greater than 38dyn / cm, if the plastic permeability will float on the ink surface.