Interfacial Bond Degradation in Laminated Flexible Packaging Film
Polyurethane bond degradation in laminated flexible packaging is driven by Corona decay, slip amide migration, and moisture hydrolytic cleavage at film boundaries
ATR FTIR Surface Spectroscopy
Molecular Identification
Infrared radiation interacts with the topmost atomic layers of a solid substrate when infrared beam reflection occurs at an optical interface. Attenuated total reflection Fourier transform infrared surface spectroscopy records this vibrational response to map chemical bonds within packaging polymers and coated paperboards. Incident light penetrates a depth of approximately one micrometre into the sample during measurement.
Molecular groups absorb specific frequencies corresponding to their dipole moment changes under the evanescent wave. Analysts apply this optical method to verify polymer barrier layers and detect silicone release coatings on specialized substrates without destroying the material.
Coating Penetration
Liquid barrier dispersions migrate into cellulose matrices during high speed gravure coating operations and alter seal integrity. Spectroscopic mapping quantifies binder migration by measuring ester carbonyl stretching bands at specific wavenumbers across cross sections of coated paper. Processing engineers adjust dryer temperature profiles and blade pressures when infrared absorbance ratios indicate uneven coating distribution on the moving web.
Seal failure rates decrease when the analytical data confirms uniform latex distribution across the paperboard surface.
Adhesion Failure
Delamination of polyethylene extrusion laminates on foil substrates originates from oxidized polymer degradation products at the bonding interface. Spectroscopic analysis isolates hydroxyl and carboxyl groups that form during corona discharge treatments on extrusion lines. Converting facilities establish threshold absorbance values for surface oxidation to guarantee reliable glue joint formation during subsequent carton folding and sealing operations.
Accurate interfacial chemistry control prevents adhesive separation on high speed packaging lines.