Corona Decay Kinetics and Solventless Adhesive Wetting in Polypropylene Lamination
Corona decay on polypropylene impairs solventless adhesive wetting, requiring in-line treatment to maintain dynamic surface energy above 40 dyn/cm.
Interphase Delamination
Adhesion Failure
Polymer coating separation during carton converting occurs when interphase delamination breaks the bond line between extruded barrier films and cellulosic substrates. Extrusion coating lines apply molten low-density polyethylene onto bleached kraft boards at high speed, creating a transition boundary prone to shear failure under mechanical stress. Weak bonding forces arise from insufficient thermal oxidation of the polymer melt before nip roll contact, preventing proper hydroxyl group interaction with the paper surface.
High speed converting operations impose sudden peel forces on folded carton blanks, causing the plastic layer to lift cleanly from the paperboard.
Barrier Breach
Gas migration rates increase exponentially once moisture vapor transmission barriers lose structural continuity across crease lines. Oxygen transmission through corrugated box walls depends entirely on continuous polymer film integrity, and localized separation lets ambient humidity degrade interior food contents. Microscopic gaps at structural fold zones expand during automated filling cycles, allowing grease and vapor penetration into the packaged goods.
Bond Integrity
Analytical testing methods measure peel strength through standardized tensile pulling across a fifteen millimetre sample width at a constant separation speed of three hundred millimetres per minute. Laboratory technicians clamp separated layers into jaw grips to record the maximum force required for layer separation, expressed in newtons per metre. Production quality auditors rely on these force values to verify that thermal extrusion temperatures remain high enough for adequate polymer oxidation during high output runs.