Bending resistance is defined as the force (in Newton) that is required to bend a rectangular test piece to a specified angle, when the test piece is fixed at one end and the force is applied to its free end.
Why measure bending resistance or stiffness?
Bending resistance and stiffness is an important material property that can affect the product performance in many converting and end-use operations. Low bending resistance/stiffness causes runnability issues during printing of paper, foldability issues during converting of board into packaging boxes, and stackability issues during handling and storage of packaging boxes.