Peel Resistance
Constant velocity separation measures adhesive bond strength by pulling laminated paper and polymer film at a precise ninety-degree angle from a rigid substrate. The procedure determines the force per unit width required to dislodge a converted coating from its base stock, quantifying how well an extrusion lamination withstands mechanical stress during high-speed printing operations. Technicians mount a specimen onto a motorized tensile stage, clamp the flexible web into an overhead load cell, and peel the material apart at a steady rate of three hundred millimeters per minute.
Failure Mechanics
Interfacial separation occurs when the applied tensile load exceeds the molecular attraction between the polymeric adhesive and the underlying cellulose fibers. Clean release along the boundary reveals low chemical affinity, whereas substrate tearing demonstrates that the bond strength surpasses the internal cohesion of the paper stock. Operators examine the separated surfaces visually to confirm whether detachment leaves a polymer residue behind on the web.
Low grammage substrates demand careful calibration of the load cell because excessive tension stretches the paper web rather than lifting the coating, generating false readings that distort internal quality control records.
Production Tolerances
Converting plants establish minimum pounds per inch thresholds to prevent delamination during subsequent hot foil stamping and UV coating stages. High-speed folding carton lines require consistent adhesive retention to withstand the sharp bending forces applied by automatic gluing machinery. Laminators adjust extrusion temperatures and corona discharge intensity when peel values fall below internal mill specifications.
Controlled adhesive application prevents edge lifting on finished packaging products.
