Frictional Resistance
Tangential force ratio required to initiate sliding movement between two contacting material surfaces under normal compressive load defines surface resistance. Evaluated on an inclined plane or horizontal sled apparatus, the static coefficient of friction measures the initial resistance to movement between paper, paperboard or corrugated shipping container surfaces. This mechanical value governs package stability, automated sheet feeding and pallet stacking security across distribution environments.
It stops applying once kinetic movement begins, where dynamic friction coefficients determine continuous sliding resistance.
Surface Slip
Chemical additives like micronized polyethylene waxes, silicones and silica slip agents modify the frictional characteristics of overprint varnishes. Formulations designed to optimize static coefficient of friction balance package slip through converting equipment against stack stability during palletization. High friction values impede sheet separation in folder-gluers, leading to misfeeds and equipment jams.
Low surface friction causes smooth printed cartons to slide out of alignment during high-speed conveying.
Stacking Stability
Distribution operations require predictable frictional resistance to prevent unitized pallet loads from collapsing during truck transport and forklift handling. Applying static coefficient of friction specifications between zero-point-four and zero-point-six ensures shipping boxes remain stable without slipping off warehouse pallets. Corrugated board converters apply anti-skid coatings to outer liners to prevent stacked container slippage on automated transport systems.
Sourcing teams verify slip properties across different paperboard coatings to balance carton erector throughput with warehouse storage safety. Consistent surface friction controls reduce damaged product returns caused by sliding pallets in transit. Packaging engineers rely on frictional testing to design safe, stable transport packaging systems.
