Failure analysis of packaging materials

Importance of the Topic

Multi-layer packaging materials are widely used across industries to protect products, extend shelf life, and guarantee safety. Complex compositions involving polymers, adhesives, coatings, and metal foils are prone to microscopic defects that can compromise barrier properties and product integrity. Rapid and precise identification of such defects is critical in quality control and failure analysis to prevent costly recalls and ensure compliance with regulatory standards.

Objectives and Study Overview

This application note demonstrates the use of FT-IR microscopy for failure analysis in packaging materials. Two primary case studies are illustrated: 1) identification of contaminants in a defective multilayer foil, and 2) evaluation of coating homogeneity and damage in acrylic and melamine layers. A third example investigates cold seal peeling and underlying layer degradation.

Methodology and Instrumentation

The study employed a LUMOS II FT-IR microscope operating in ATR, transmission, and reflection modes, combined with OPUS software for data acquisition and analysis. Key features include automated ATR measurements using a germanium crystal, motorized stage for mapping, and integration of OPUS/SEARCH and OPUS/SEARCH mixture analysis libraries.
Instrumentation Used:

• LUMOS II FT-IR Microscope
• OPUS 7.5 with OPUS/SEARCH and ATR-COMPLETE spectral library

Main Results and Discussion

Case Study 1: Multilayer Foil Defect Analysis

• Spectrum search identified the base polymer as polyvinylidene chloride–acrylate copolymer.
• Difference spectra and library subtraction revealed a polyamide resin contaminant in black spot regions.
• Mixture analysis detected polyethylene in the second defect spot alongside the base polymer.

Case Study 2: Coating Homogeneity Assessment

• An ATR mapping grid (1.5×2.0 mm) collected 1200 spectra with 32×32 μm resolution.
• Cluster analysis using Euclidean distance classified spectra into melamine-coated and defective regions.
• Chemical imaging highlighted areas with reduced melamine signal and increased polypropylene-co-ethylene from substrate.

Case Study 3: Cold Seal Examination

• PCA decomposed spectral variance, isolating acrylic coating, cold seal polymer, and defect signature.
• Winner Takes All compositional imaging overlaid three components: acrylic, cold seal, and defect.
• Library search identified acrylic dispersion, silicate-filled acrylic cold seal, and viscose in peeled areas.

Benefits and Practical Applications

FT-IR microscopy provides high spatial resolution chemical insights into micro-scale defects, enabling:

• Rapid identification of contamination and delamination sources.
• Non-destructive mapping of layer composition and homogeneity.
• Informed decisions for material selection and process optimization in packaging production.

Future Trends and Possibilities

Advances in FT-IR imaging and data analysis are expected to further enhance diagnostics in packaging QA/QC:

• Integration with machine learning algorithms for automatic defect classification.
• Extended spectral libraries covering novel polymers and additives.
• High-speed mapping through optimized motorization and detector technologies.

Conclusion

The LUMOS II FT-IR microscope, combined with advanced OPUS software, demonstrates robust capabilities for failure analysis of packaging materials. Automated ATR measurements, chemical imaging, and multivariate data analysis facilitate precise detection and characterization of defects, supporting quality assurance and product development in packaging industries.