The bursting strength test of paperboard, including linerboard, is a composite measure of certain properties of the sheet structure, principally tensile strength and elongation. In general, bursting strength is dependent on the type, proportion, preparation, and amount of fibers present in the sheet and on their formation, internal sizing, and, to some degree, the surface treatment. While bursting strength is an empirical property, this test, in combination with grammage (basis weight), serves to define “standard grades” in commerce.
Bursting strength of a material is defined as the maximum hydrostatic pressure required to produce rupture of the
material when a controlled and constantly increasing pressure is applied through a rubber diaphragm to a circular area, 31.5 mm (1.24 in.) diameter. The area of the material under test is initially flat and held rigidly at the circumference but is free to bulge during the test.
Scope and summary
- This method describes a procedure for measuring the bursting strength of paperboard, including linerboard having a bursting strength of approximately 350 kPa (or 250 kPa by doubling the test specimens) or greater,
employing a disk-shaped, molded diaphragm type instrument.
- A specimen of board is clamped between two platens with circular openings in their centers. An
expansible diaphragm is distended through the lower platen by means of hydraulic pressure until the specimen bursts. The maximum hydraulic pressure when the specimen ruptures is recorded.