Multilayer packaging material analysis using Laser Direct Infrared (LDIR) Imaging

Significance of the topic

Multilayer laminate packaging materials are engineered with multiple polymer layers to control strength, barrier properties and environmental protection. Precise mapping and thickness measurement at the micrometer scale are critical for ensuring product integrity, safety and regulatory compliance.

Objectives and overview of the study

This study assesses the Agilent 8700 Laser Direct Infrared (LDIR) Chemical Imaging System for rapid, high-resolution identification and visualization of polymer layers in multilayer packaging, addressing quality assurance, failure analysis and reverse engineering needs.

Methodology and Used Instrumentation

Sample preparation employed an Agilent laminate holder and Sample Planer microtome to create a flat cross section in minutes. A high-magnification visible light microscope (up to 1 µm resolution) provided an overview of the layer structure. Automated ATR contact with live imaging feedback enabled optimal spectra acquisition. Chemical imaging was performed via point scanning, multi-peak analysis and ATR mosaicking, supported by the intuitive Agilent Clarity Software.

• Agilent 8700 Laser Direct Infrared (LDIR) Chemical Imaging System
• Agilent Clarity Software
• Laminate sample holder with built-in clamp
• Sample Planer microtome device
• High-magnification visible light microscope (1 µm spatial resolution)
• Automated ATR mosaicking and spectral library search

Main results and discussion

• Mapped a food packaging laminate with layers as thin as 2.6 µm within a total thickness of 117 µm.
• Chemically identified polyethylene, polyamide, polypropylene, polyurethane and poly(ethylene vinyl alcohol) layers via automatic library matching.
• Generated high-resolution infrared images at 0.2 µm pixel size in under 14 seconds.
• Seamlessly mosaicked ATR images across a 230 µm sample width with perfect visual-chemical alignment.
• Distinguished colored polyethylene layers that were visually indistinguishable by optical inspection alone.

Benefits and practical applications of the method

• Rapid sample preparation (< 5 minutes) without resin embedding or polishing.
• Excellent spatial resolution (down to 1 µm) for precise thickness measurement.
• Automated workflows with minimal chemometric complexity.
• Real-time chemical mapping supports quality control, failure investigation and material design.
• Fast spectral acquisition (< 5 seconds per point) accelerates analysis.

Future trends and potential applications

Emerging developments may include integration of artificial intelligence for spectral interpretation, higher throughput sample handling, extension to diverse packaging polymers and in-line monitoring of layer integrity during production. Combining LDIR imaging with complementary techniques could further enhance material characterization.

Conclusion

The Agilent 8700 LDIR Chemical Imaging System delivers rapid, high-resolution chemical identification and thickness measurement of multilayer packaging materials. Its intuitive, automated workflow streamlines analysis for quality assurance, failure analysis and reverse engineering.