The importance of paperboard stiffness

For containerboard and whiteboard, stiffness is a basic performance indicator.
The stiffness of the paper is a very important indicator, which directly affects the stiffness of the crease (another influencing factor is the die-cutting pressure), thus affecting the molding of the finished product. If the stiffness is small, the finished product is easy to be crushed and warped; if the stiffness is large, the finished product is difficult to form.

Packaging paper has requirements for stiffness. The stiffness of different quantitative paper is different. Generally, it is proportional to the square of the thickness. The thicker the cardboard, the higher the stiffness.
 

Factors Affecting Flexural Stiffness

There are many factors that affect stiffness. The thickness and elastic modulus of the cardboard are the most basic factors that affect the stiffness of the cardboard or paper. When the thickness is constant, the stiffness increases as the tightness increases. When the weight is constant, it increases slightly and then decreases slightly with the increase of tightness, but the general trend is a net increase.
 

Test method for stiffness of paper and cardboard
The measurement method of stiffness includes fixed and non-fixed angles to test the flexural strength of the sample, and the strength change of the sample is measured by free bending. Some test methods do both. The stiffness of the paper is often measured by the Clark and Greer methods.