Often fibers in textile substrates are deficient in one ormore properties or improved properties are desired for the substrate. Textilefinishing provides a method whereby deficiencies in the textile can becorrected or specific properties can be introduced. Physical finishingtechniques (dry finishing processes) or chemical finishing methods (wetfinishing) are used. Physical finishing is usually carried out on the yarn orformed textile substrate, whereas chemical finishes can be added to thespinning bath prior to fiber formation for man-made fibers or applied toindividual fibers, yarns, or completed textile structures.


Physical Finishes and Finishing


Physical finishing methods for textiles include opticalfinishing, brushing and napping, softening, shearing, and compacting of thetextile structure.


Optical Finishes


Luster may be imparted to a fabric by physical means. Thetechniques basically involve flattening or smoothing of the surface yarnsusing pressure.


Beating of the fabric surface or passing the fabric betweenhard calendering rolls under pressure and with some friction will tend toflatten out the yarns and lower light scattering by the fabric surface, therebyimproving reflectance and luster. Luster may be improved further if the calenderingrolls are scribed with closely spaced lines which will be imprinted on thefabric to reinforce light striking and reflecting from the fiber surface.Similar techniques can be used to impart optical light interference patternsto the fabric. Thermoplastic fibers which can deform under heat and pressurecan most readily be modified to impart luster.


Brushing and Napping


Physical delustering of a fabric as well as bulking andlofting of the fabric can be achieved by' treatments which roughen the fibersurface or raise fibers to the surface.


Fiber raising processes such as brushing and nappinginvolve use of wires or brushes which catch yarns in the textile structure andpull individual fibers partly from the yarn structure. The resulting fabric iswarmer, more comfortable, and softer.


Softening and Shearing during calendering or beating of afabric interaction between individual fibers within yarns may be lessened andthe textile structure softened.


Also, when a smooth textile structure free of raised surfacefibers or hairiness is desired, the fabric may be sheared by passing thefabric over sharp moving cutting blades or by passing the fabric over a seriesof small gas jets which singe and burn away raised fibers.



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Originallypublished in New Cloth Market: September 2009