Measuring Specular Gloss Changes during Standard Paperboard Rub Tests
Measuring specular gloss changes before and after standard rub tests quantifies surface coating durability using exact optical angle decay metrics.
Slip Agents
Surface Friction
Migratory additives reduce the coefficient of friction on film substrates to facilitate automated processing. Slip agents inhabit the formulation of polymer resins and migrate to the exterior surface after extrusion. This physical movement creates a microscopic lubrication layer that prevents layers of plastic from adhering to each other during windup or transit.
Manufacturers monitor this migration process to ensure the film releases from a stack or roll without distorting the underlying substrate or causing blockages in high-speed converting machinery.
Application Threshold
Film converters evaluate additive concentration by measuring the ease of separation between two identical plies of material. A high degree of surface smoothness prevents static accumulation and assists the flow of materials through pouching and filling equipment. Formulators control the rate of migration through the selection of specific fatty acid amides that remain stable under thermal processing.
Rapid cooling during the production line affects the speed of these particles as they move toward the exterior, so production managers adjust quench temperatures to maintain the required release characteristics. Variations in cooling speed alter the density of the lubricant film and dictate the efficiency of downstream operations.
Conversion Tolerance
Finished packaging lines demand precise performance from slip agents to avoid registration errors during printing or vacuum sealing. Friction levels must drop sufficiently to prevent jamming on mechanical mandrels while maintaining enough grip for label application and transport through secondary packaging stations. Excessive migration leaves an oily residue that hampers the adhesion of inks and hot melt adhesives on the substrate surface.
Controlling the output of these chemical constituents requires a balance between mechanical throughput requirements and the surface energy necessary for post-processing treatments. Proper management of these additive concentrations prevents mechanical failure on filling lines while preserving the integrity of the surface for bonding and graphical clarity.