Measurement Efficiency
Measurement of the efficiency with which a dye substance is absorbed and retained by a substrate during the coloration process. A high color yield indicates that a large proportion of the applied pigment has fixed to the fiber rather than remaining in the liquor. This value determines the cost effectiveness of a dyeing recipe in bulk production.
Calculation Method
Assessment involves measuring the reflectance of the dyed material using a spectrophotometer to derive the K/S value based on the Kubelka Munk theory. This ratio accounts for light absorption and scattering at specific wavelengths. Higher values correspond to deeper shades for a given concentration of dye.
Influencing Factor
Fiber morphology and the presence of functional groups on the polymer chain dictate the maximum possible saturation. Pre-treatments such as mercerization or causticization increase the available surface area and amorphous regions, which naturally improves the color yield of reactive dyes on cotton. Temperature and pH must stay within narrow bands to prevent the hydrolysis of the dye molecule.
Commercial Relevance
Buyers use these figures to compare the efficiency of different mills when using identical dyestuffs. Lower yields result in higher wastewater loading and increased chemical costs for the factory.
