Deformation Resistance
Progressive deformation occurs in paperboard packaging under constant stress. While instantaneous elastic response happens immediately, carton creep describes the slow, time dependent increase in strain under a static load. This phenomenon typically results from the molecular rearrangement of cellulose fibres.
It leads to the eventual collapse of stacked boxes even when the weight remains below the initial compression strength rating.
Load Duration
Stacking height in a warehouse determines the magnitude of the pressure applied to the lowest unit. If a pallet remains in storage for several months, carton creep causes the side walls to bulge outward and the corners to buckle. This reduction in vertical support capacity increases as the duration of the load extends.
A carton that supports 500 kilograms during a short test might only sustain 250 kilograms over a ninety day period.
Environmental Sensitivity
Moisture content in the air accelerates the rate of physical breakdown. Fluctuations in relative humidity trigger internal stresses that worsen carton creep by allowing fibres to slide past one another more easily. When the ambient humidity rise from fifty percent to ninety percent, the failure time of the board often drops by a factor of ten.
High quality liners with better chemical bonding help to resist this movement.
