Surface Energy Shift and Gloss Drift under Friction Sled Cycles
Friction sled cycles strip migratory slip agents, elevating polar surface energy while generating micro-roughness that causes severe specular gloss drift.
Thermal Lamination Scuffing
Abrasion Defect
Surface defects on laminated paperboard can occur when the protective film layer is subjected to friction and heat during high-speed converting. The problem of thermal lamination scuffing describes the physical scraping or clouding of the laminated surface that happens during processing. This defect ruins the high-gloss or matte appearance of luxury packaging.
Thermal Vulnerability
Friction between the moving film and the metal parts of the folding-gluing machine generates localized heat that softens the thermoplastic lamination layer. Once softened, the surface is easily scuffed by guide rails, belts, or rollers, which leaves visible marks or scuffs. This issue is more common with matte films, where the textured surface is sensitive to polishing by friction.
Preventing this scuffing requires careful control of the machine speed and pressure settings.
Process Adjustment
Evaluation of this issue involves running simulated scuff tests, such as the Sutherland rub test, under controlled heating conditions to replicate the friction of the converting line. Converters can reduce the risk of scuffing by using films that have been treated with hard-coat coatings or by applying a thin layer of wax or silicone to the film surface. Machine operators must ensure that rollers are clean and turn freely, as a jammed roller will scratch the moving web.
Proper maintenance of the conveying equipment ensures that the laminated board passes through the converting line without any loss of surface gloss or clarity.