How to Test Paper Hardness

Paper hardness determines what it is used for.

Paper is one of the most commonly used products in the modern world. Papers are used in a variety of ways, ranging from publishing of newspapers and books to brochures and magazines. Paper is also used in every supermarket for wrapping items shoppers buy on a daily basis. The different uses paper is applied to requires different specifications. One of the most important specifications is paper hardness. A newspaper requires a light paper, but a book cover requires a hard paper. There are various methods that can be used to test paper hardness so the proper paper can be used for specific tasks.

Things You'll Need

• Paper caliper

Instructions

1. Measure the thickness of the paper with the paper caliper. This is important to determine the thickness of books and other paper materials. This can be measured with the use of a parallel rolling cylinder, placed under a preset pressure. You should take a reading after a certain time. It is important the machine direction (MD) and cross-machine direction (CD) are uniform.

2. Bend the paper to test the bending stiffness. This refers to the bending resistance of the paper. Tests can be classified into 2-point bending and 4-point bending. Two-point bending is used for thin materials, and 4-point bending is used for thicker paper, such as cartons and boards.

3. Tear the paper to test the tensile strength. The ZD Tensile Test determines the amount of stress it would take to tear the paper apart. The Zero Span Test determines the utmost strength of pulp fibers of the paper.

4. Conduct a compression test. You can do this using various compression tests, such as the Short Span Compression Test, Ring Crush Test and the Edgewise Compressive Strength. These tests measure the buckling properties of the paper.

5. Tear the paper. Tear testing calculates the breaking and pulling out of the fibers in the tearing line. It also determines the maximum bursting strength and fold endurance of the paper.

References

• Institute of Paper Science Technology: Paper Testing Methods Lecture