Rupture Resistance
Hydraulic force application through a circular elastic diaphragm measures multidirectional tensile failure thresholds in heavy paperboard grades. The determination of bursting strength ISO 2759 quantifies maximum resistance against fluid pressure before structural material rupture occurs. Testing applies fluid pressure beneath a clamped circular specimen at a constant volumetric displacement rate.
Hydraulic force expands the flexible diaphragm until the test piece ruptures. Fiber bonding and individual fiber length set the upper bound of energy absorption. The protocol excludes corrugated combined board, paper grades under fifty kilopascals strength, and lightweight tissue substrates.
Pressure Rate
Pumping rate stability governs test repeatability across testing laboratories. Hydraulic oil pressure increases at a controlled rate of one hundred seventy milliliters per minute until failure. Deviations in oil viscosity alter pressure ramp curves and skew recorded bursting strength ISO 2759 values.
Calibration verifies diaphragm height resistance at specific pressure thresholds.
Packaging Constraint
Box compression performance relies primarily on edge stiffness rather than bursting capability. While bursting strength ISO 2759 remains a commercial standard for containerboard sales contracts, containment puncture resistance correlates more closely with multidirectional tensile energy absorption than pure bursting resistance. Liquid packaging board specifications require minimum burst values to ensure carton integrity against internal fluid movement during transportation.
Fluting materials rarely undergo burst testing because structural geometry prioritizes flat crush strength over planar tensile resistance. High bursting values require unbleached softwood kraft pulp addition to linerboard formulations.
