Solid Laminates
The protection of graphics from environmental damage such as abrasion or fingerprints, UV exposure etc. has become a major industry. Typically a transparent solid polymer overlay is laminated to the plastic or paper print substrate using heat and/or pressure.
In many cases the substrate in use is covered edge to edge with ink. The overlay that must adhere to the substrate is actually adhering to the ink layer not the substrate itself. The ink must also have good adhesion to the substrate. This sometimes results in difficulty in getting a good bond between the multiple layers of the laminate. In such cases the use of an adhesive is required. This adhesive sits in between the layers that have poor adhesion to each other. The adhesive may be a solid adhesive applied to the overlay or it may be a liquid adhesive applied over the print graphics and cured. The overlay is then laminated to the adhesive treated graphic. In applications such as credit cards or ID documents it is necessary for the overlay with adhesive to have a strong permanent bond to the ink and the substrate, in order to prevent tampering with the graphics.