Near Infrared Spectroscopy in the Textile Industry

The extent of the work for the classification of quality in the textile field has grown rapidly in the last few years. Planning and checking of quality assurance measurements are necessary in order to control and to improve internal production standards in textile industry. Raw fibres must be tested when supplied to the factory and finishing textile process must be monitored. Tests must be quick and targeted, possibly at-line, reproducible and precise in order to cover pre-definite concentration standards. A very useful measuring technique for product and quality control in the textile industry is Near Infrared (NIR) spectroscopy. NIR can be used for many different applications, such as to identify fibers in the raw state, in yarns or finished products and to identify foreign materials in textiles. NIR spectroscopy is also widely applied for the quality control of natural fibers, showing different features in their morphology and chemical composition and even processability as well as for quantitative blend fiber composition. The rapid testing of samples without destroying their integrity and the fact that no sample pretreatment is required before the analysis have promoted NIR spectroscopy in controlling industrial manufacturing processes. Analytical data can be evaluated using modern chemometric methods which, by correlating NIR measurements with a set of independent measured characteristics, collect the maximum information from experimental results, evaluate and describe the data with a calibration set and provide a calibration curve useful to test the desired textile quality properties. This work shows a variety of different applications in the textile area for the use of NIR spectroscopy and related chemometric methods for the descriptions and calibrations of experimental data. The discussion summarizes different research works including the identification of animal hair fibers (wool, cashmere, yak and angora rabbit) and man made cellulose fibres (viscose, modal and lyocell). NIR methods for the characterisation of textile materials such as the determination of humidity and greasy matter content on wool combed sliver and the determination of coarse hair amount in cashmere samples were reported. NIR spectroscopy was also investigated as a method to check textile processes such as the degumming and weighting of silk. In this case methods were developed to check the loss and the increase in weight of silk fabrics as well as the sericin and grafting agent amount in effluents.