Analysis of textile using near-infrared spectroscopy

Analysis of Textile using Near-Infrared Spectroscopy

Importance of the Topic

Near-infrared spectroscopy (NIRS) has emerged as a vital tool in textile analysis, enabling rapid, non-destructive assessment of fiber types, finishes, moisture, and additives. By offering real-time information on process streams and finished materials, NIR methods enhance quality control, reduce waste, and support sustainability initiatives in textile production and recycling.

Objectives and Study Overview

The primary goal of this bulletin was to demonstrate a range of NIR applications in textiles, including:

• Quantifying oil finish and bond on nylon fibers and threads
• Distinguishing fiber types (nylon, polyester, polypropylene)
• Monitoring heat-set temperature in nylon carpet
• Assessing blend ratios in fiber mixtures
• Measuring moisture, oil, and total solids in bath liquors and wool
• Determining fluorocarbon finish on polyester
• Tracking polybenzimidazole (PBI) in fire-retardant fabrics

Methodology and Instrumentation

Studies employed reflectance, transmission, and interactance sampling modes across the 1100–2500 nm spectral region. Calibration models were developed using partial least-squares regression, targeting diagnostic absorption bands for finishes (1500–1900 nm), moisture (1440, 1930 nm), oil (2266 nm), and specific additives (e.g., PBI at 1686 nm). Key steps included multiple scans with sample repositioning to average inhomogeneity and external validation with independent sets.

Main Results and Discussion

Overall, NIR methods achieved robust performance:

• Oil finish on nylon fibers: SEC 0.06–0.2 % using remote and interactance probes
• Heat-set detection in nylon: classification by spectral changes at 2020–2130 nm
• Bond and finish on thread: SEC 0.6 % at 1516 nm and 1 % at 1880 nm
• Fiber identification: 100 % correct classification of nylon, polyester, polypropylene, including blends
• Blend ratios and moisture/finish: SEC 0.5 % moisture, 0.1 % finish, with separate calibrations for each fiber type
• Fluorocarbon finish on polyester: SEC 0.02 % over 1200–2400 nm
• Polyester in cotton blend: SEC 1 % at 1660 nm in reflectance mode
• PBI in fire-retardant fabric: SEC 0.1 % at 1686 nm
• Wool moisture and oil: SEC 0.02 % (1920 nm) and 0.001 % (2266 nm)
• Total solids in bath liquor: SEC 0.2 % after two-wavelength correction

Benefits and Practical Applications

NIR spectroscopy enables on-line monitoring of textile processes, minimizes sampling delays, and reduces chemical waste. Applications range from yarn finishing control to blend verification, carpet manufacturing, fabric fire-retardant treatment, and liquor bath quality, supporting QA/QC in both R&D and industrial environments.

Future Trends and Potential Applications

• Integration of advanced chemometrics and machine learning for improved prediction accuracy
• Miniaturized, portable NIR sensors for field inspection and recycling operations
• Multimodal process analyzers combining NIR with mid-IR or Raman for comprehensive fiber characterization
• Real-time feedback control in continuous finishing and dyeing lines
• Expanded use in sustainable textiles, bio-based fiber assessment, and waste-fiber sorting

Conclusion

This collection of feasibility studies confirms that NIR spectroscopy is a versatile, precise, and rapid approach for a wide range of textile analyses, from fiber identification and blend ratios to finishing agents, moisture, and additive monitoring. Implementing these methods can strengthen process control and quality assurance across the textile industry.

Used Instrumentation

1. NIRS XDS RapidContent Analyzer Solids (2.921.1120)
2. NIRS XDS RapidLiquid Analyzer (2.921.1410)
3. NIRS XDS Process Analyzer with DirectLight/NonContact (2.928.0310)
4. Legacy Model 5000 analyzers with remote reflectance, spinning sample, and horizontal modules

Reference

Application Bulletin AB-413_1_EN, NIRSystems, Analysis of Textile using Near-Infrared Spectroscopy