Coating & Laminating in Flexible Packaging Applications
There are many types of laminates used for decorative and “touch and feel” applications. What type of laminating films are being used now for both decorative and functional applications?
Davis-Standard engineers solutions based on a customer’s technical and business needs. The actual product structure varies by end-use application and preference of our global customers for line speed, materials used and other factors.
What needs to be considered when laminating digitally printed films?
We work with customers to understand their requirements. These are some of the questions that help us identify parameters when designing the line:
Is the coating water-based or solvent-based?
What type of coater is applying the coating? (gravure, rod, slot die)
- Is the coating applied to the printed web or other web?
- Is the coating applied to the printed surface or the back side?
- Is the lamination process utilizing a heat-bond adhesive or a pressure-sensitive adhesive?
- What is the temperature of the two webs at the point of lamination?
- Is there any cooling after the lamination?
- Does the lamination nip require high pressure?
Have there been any changes in recent years in machinery for applying laminating films that have helped with faster speeds and help eliminate waste?
Machinery has definitely evolved to address speed requirements and waste reduction. Drives and motors are more accurate, providing superior tension control for diverse substrates. Both laminating rolls can be driven to control web qualities such as curl. There are new rubber compounds to support superior web handling. Internal roll designs enable uniformity of cross-web temperature and create uniform lamination properties. By replacing pneumatic cylinders with servo drives or with an electro-mechanical positioner, process control is better. And finally, there is more accurate tension control of both webs because of advances in web handling capabilities.
What are some of the most common problems you see with printed materials that need to be laminated?
There are four primary issues we see frequently. The first is when tension control of the laminate web does not match the primary web. The second is when a printed surface is scratched from the coater application. Third is mismatched temperature of both webs. And fourth, when the rubber laminator roll is damaged, cut, abraded or too soft.
What are some key tips to assure proper adhesion and to eliminate any challenges during the film laminating process?
Key Tips Include:
- Match the temperature of both films.
- Control the tension of both films independently.
- Achieve uniform and correct hardness of the rubber compound.
- Reduce the temperature differential across the laminator roll.
- Maintain uniform nip impression.
- Have better control of each aspect of the process.