Prevention of curling of paper-plastic composite products (2)

With the rotation-straight-assured form of movement of BOPP film throughout the production process, the diameter of each roll of BOPP film is continuously decreasing, and the diameter of each roll of paper-plastic composite product is continuously increasing. In order to keep the line speed of the heated roller consistent with the main power, the speed of the BOPP film feeding mechanism must be continuously increased. Its speed is as follows:

Heating roller (ψ270mm): BOPP film (ψ300mm)=1:0.9

Heating roller (ψ270mm): BOPP film (ψ200mm)=1: 1.35

Heating roller (ψ270mm):BOPP film (ψ90mm)=1:2.84

In order to ensure that the film is not forcibly stretched, the tension control of the discharge axis of the BOPP film should be gradually relaxed, and the discharge shaft and the shaft seat, the flattening of each channel, the surface of the adjustment roller should be kept clean and have good lubrication.

The change of finished product winding is contrary to the discharge of BOPP film. It does not gradually decrease, but gradually increases. With each 500 pairs of open sheets as a finished product, the final speed reduction value of the 787×540 split paper is 2.74 times, and the final speed reduction value of the 880×620 split paper is 3.05 times. The tension control of the winding device should be matched.

5. Take necessary protective measures

The necessary protective measures help to avoid or reduce the occurrence of curl in the paper-plastic composite product.

(1) There should be a certain period of storage before division

The firm adhesion of the paper-plastic composite product does not occur when it is just released from the heat-pressing mechanism, but remains after the adhesive curing effect and the BOPP film and the paper stress are adapted to each other, and the post-storage system is not reserved for more than 24 hours. If the segmentation is premature, the shrinkage response of the BOPP film will increase and curling will occur.

(2) moisture-proof of paper-plastic composite semi-finished products

The residual temperature of paper-plastic composite semi-finished products just peeled off from the laminating machine is higher, and the hotter paper-plastic composite semi-finished products will dissipate heat to the outside while absorbing cold outside air and cooling down. This cooling will cause the increase of humidity. If the semi-finished product is placed directly on the ground, it will be easier for the paper to absorb moisture, resulting in split curling. (Finish)