The image life of printed media displayed in both typical office and outdoor environments can be extended by lamination or encapsulation. While natural aging is the most reliable method of assessing lamination adhesion, the length of the time required makes this method impractical for most materials. The peel strength method allows comparative studies of prints and laminating films.

Good adhesion is prime consideration for laminating films and prints. A laminating film, which does not adhere to a print or vice versa generally, has no commercial value. This method is used to obtain comparative data of peel strength of encapsulated or laminated media.

Peel strength can be measured up to a point where the peel strength is equal to the tensile strength of the adhesive or the print.

In many applications, having sufficient laminate adhesion strength is important to give satisfactory performance. The property is also important in determining the uniformity of quality.

A rough or raspy peel test will produce a higher RMS value than one that is smooth and continuous. It can be related to "zippering," "shocking," or "stick-slip."

Bond Strength and Interfacial Adhesion-The bond strength of a laminate essentially depends on both the adhesive and the cohesive strength of the laminating system. Peel strength of the laminate is typically determined by debonding the laminate using 180° peel test. Fig. 2 presents five possible modes of failure: (1) debonding of the ink receptive underlayer from the substrate (2) debonding of the ink receptive top layer from the underlayer, (3) debonding of the adhesive from the top ink receptive surface, (4) debonding the adhesive from the laminating film, (5) the substrate or film failure tear. The failure of the laminate will occur at its weakest link. It is generally desirable to have high bond strength to the recording element with failure occurring where the adhesive debonds from the ink receptive.