1. Accurate and reliable web tension control:
The tension of the substrate- from unwind to rewind should be precisely regulated to avoid formation of creases, wrinkles, curl etc. And obtain a good finished roll of laminated material. The winding pressure must also work uniformly over the whole web width as otherwise there will be risk of telescoping.
2. Regular and uniform adhesive application:
In the solvent adhesion process, the speed differential, temperature determines the adhesive quantity. And gap between the coating rolls. These variable should be monitored and controlled accurately as this will not only influences the overall properties of the final laminate but also affect the economies of the process.
3. Nip pressure and temperature control:
The laminating adhesive coated web is combined to the corona treated secondary web at 50 to 70 degree , by heating the nip roller. The nip pressure must be worked evenly over the web. If the pressure is too low the air will get entrapped. If pressure is too high it will lead to squeeze.
4. Corona treatment:
While some films may be treated to the proper level, other films may need additional corona treatment to promote adhesion.
5.Roll stage:
The rolls are stored in hot room to accelerate curing which result in better bond strength and visual characteristics. To avoid the rolls taking a set during the curing process, they should be suspended horizontally and the store in a track.
6. Speckling:
This occurs when there are while spots in the laminate at various positions. This is due to incorrect gsm of adhesive used in the process of lamination.
