Polyurethane Tactile Film Surface Chemistry and Abrasion Dynamics
Polyurethane tactile films trade high material costs for self-healing elastomeric scuff resistance, requiring precise thermal nip control and high dyne levels.
Micro-Scratching
Surface Defect
Minor abrasions occurring on high-gloss coatings or polymer barrier films during converting and transport reduce the optical quality and aesthetic value of premium packaging. This phenomenon of micro-scratching occurs when high-speed paperboard webs run over misaligned metal rollers or guide plates on the folder-gluer. The scratches are typically very shallow but scatter light in a way that creates a hazy or dull appearance on printed surfaces.
This surface damage is particularly visible on dark, matte, or high-gloss black finishes. It can also compromise the integrity of thin aluminum barrier layers in laminated materials.
Technical Origin
Mechanical friction and dust accumulation are the main causes of these small abrasions. Paper dust generated during slitting acts as a fine abrasive when caught between the moving web and stationary machine components. Hard particles embedded in the surface of rubber draw rollers can also create repetitive scratch patterns.
Keeping tension uniform prevents the web from sliding over surfaces where it should roll, reducing abrasive friction.
Diagnostic Method
Measurement of surface haze or gloss reduction provides a quantitative way to assess the severity of these defects. Laboratory testing uses a specialized stylus or gloss meter to compare affected and unaffected areas under controlled light. Visual checks are performed using low-angle illumination to reveal the orientation of the scratch lines.
This analysis helps identify which rollers are causing the friction.