Failure analysis of packaging materials

Significance of the Topic

Packaging materials are engineered as multilayer systems combining polymers, adhesives, coatings and metals to achieve barrier function, sealing and printability. Microscopic defects in these complex assemblies can compromise product integrity, lead to contamination or reduce shelf life. High-resolution chemical analysis is essential for failure investigation and quality control in food, pharmaceutical and industrial packaging.

Objectives and Study Overview

This application note illustrates the use of FT-IR microscopy to detect, identify and map microscopic defects in packaging films. Three case studies are presented: identification of inclusions in a transparent foil, assessment of coating homogeneity on a polymer film and evaluation of damage in a cold-seal area after opening.

Methodology

FT-IR microscopy was performed in ATR, transmission and reflection modes with lateral resolutions down to a few micrometers. Automated mapping measurements and point analyses were acquired at 4 cm⁻¹ spectral resolution. Data evaluation employed univariate band integration, cluster analysis, principal component analysis (PCA) and mixture analysis to generate chemical images and identify spectral contributions.

Used Instrumentation

• LUMOS II FT-IR Microscope: integrated spectrometer, motorized stage and Germanium ATR crystal for automated ATR, transmission and reflection measurements.
• OPUS 7.5 and OPUS/SEARCH software: guided acquisition workflow, spectral search, mixture analysis and multivariate tools.
• ATR-COMPLETE spectral library: extensive reference database for polymer, coating and filler identification.

Main Results and Discussion

• Defect Analysis in Transparent Foil: Automated ATR mapping at 20 s per spectrum identified the base material as polyvinylidene chloride-acrylate copolymer. Spectrum subtraction and library search revealed polyamide resin in one defect and mixture analysis detected polyethylene in another.
• Coating Homogeneity on Polymer Film: A 1.5 × 2.0 mm area was mapped with 32 × 32 µm pixels (1200 spectra). Cluster analysis differentiated melamine resin coating from substrate. Dark spots exhibited reduced melamine bands and increased polypropylene-co-ethylene signal, indicating incomplete coverage.
• Cold-Seal Area Examination: ATR mapping with PCA distinguished three components—acrylic coating, cold-seal polymer (acrylic with silicate filler) and a viscose-rich defect. A “Winner Takes it All” composite image visualized spatial distribution of each component.

Benefits and Practical Applications

FT-IR microscopy with automated mapping and advanced data analysis delivers:

• Non-destructive, high-resolution chemical imaging of multilayer structures.
• Rapid identification of defect composition and distribution.
• Quantitative mapping for quality assurance and failure root-cause analysis.

Future Trends and Potential Applications

Emerging developments may include:

• Machine learning algorithms for automated spectral classification and anomaly detection.
• Enhanced detector technologies for sub-micrometer spatial resolution.
• Integration of inline FT-IR imaging for real-time process monitoring in packaging production.

Conclusion

The LUMOS II FT-IR microscope combined with OPUS software provides a powerful platform for comprehensive failure analysis of packaging materials. By coupling automated ATR mapping with multivariate evaluation, even microscale defects in complex multilayer films can be identified, characterized and visualized, supporting improved product quality and process optimization.