The Peeling Behavior of Pressure Sensitive Adhesives from Uncoated Papers

When a tape based on pressure sensitive adhesive (PSA) is peeled from paper, either the tape comes off leaving a clean paper surface or the paper undergoes catastrophic cohesive failure which is the delamination of fiber layers in the paper sheet. The objectives of this work were to determine the links between paper properties and peel characteristics. Peel tests and microscopic analysis of a variety of handmade and commercial papers yielded the following conclusions. The tendency for paper failure is not very sensitive to surface energy. Paper roughness and density seems to be the dominant factors. A relatively smooth but weak paper will give a clean peel whereas a strong but rough handsheet or filter paper will always give paper failure. Lamination pressure is also important. Peel force increases with lamination pressure up to a limit where paper failure begins and the peel force plummets. The peel response of common paper types is mapped onto a 2-D surface whose axis reflects paper surface chemical and structural properties. It is proposed that the initiation of paper failure in peel occurs at fiber ends.