A novel approach for estimating the relation betweenK/S value and dye uptake in reactive dyeing of cotton fabrics

This paper focuses on the application of a novel mathematical limit approach derived forK/S values in reactive dyeing of cotton fabrics. The relation obtained from Kubelka-Munk equation is used because the Kubelka-Munk equation is the basic relationship among fabric reflectance, fabric dye content and dyestuff characteristics. The limit approach derived in a former paper is applied to the laboratory dyeings and the dyeing behavior of some reactive dyes on cotton knitted fabric has been obtained. The results of the laboratory experiments are discussed using the new mathematical approach. When the actualK/S values obtained from the dyeings and the calculatedK/S values derived by the limit approach are considered independently, it is observed that the limit relation is valid for low dye concentration applications. When theK/S values are calculated taking theK/S value of the initial dyeing concentration (0.1 % owf) as the starting concentration by applying the result of the derived limit approach, the calculatedK/S values fit with the ones obtained in actual dyeings. It is concluded that the novel approach presented in the paper can be used in calculating theK/S values when the initial dyeings at low dye concentrations are carefully carried out.     

Assessment of color strength and color difference values of polyester fabrics containing continuous weft yarns after abrasion

This paper assesses the color difference and color strength values (K/S) obtained for eight disperse-dyed polyester fabric samples with different fabric construction parameters (weft yarn type, weft yarn count, weft density and fabric weave) after four sets of abrasion cycles. Warp yarn type and count, warp density, and warp yarn twist are the same for all fabrics. Fabric samples are dyed in a commercial red disperse dye (C.I. Disperse Red 74:1) and four different abrasion cycles (2500, 5000, 7500, 10000) are used. TheK/S values of the abraided fabrics and color difference values between the control fabric (dyed but not abraided) and abraded fabrics are calculated. The main differences in theK/S and color difference values are observed between 0–2500 abrasion cycles. The high tenacity of the polyester fibers and continuous polyester yarns causes some fuzz but no pilling formation on the fabric surface that lead to increasedK/S values and color differences. Fiber dullness, yarn thickness, yarn density and fabric weave are concluded to have different effects on the appearance after abrasion.     

Assessment of the results of different color difference formulae under different illuminants by wash fastness tests

This paper focused on the assessment of the results of two color systems (CIELAB and Hunter) and five color difference equations (CIELAB 1976, Hunter, CIE94, CMC and CIEDE2000) under different illuminants (D65, A, F11 and F2) on disperse dyed nylon fabrics after wash fastness tests. Nylon fabric samples were dyed with four disperse dyes of different hues (red, blue, yellow and black) and later they were subjected to multiple wash fastness tests in order to obtain a controlled color loss. The changes in the color coordinates of the original and washed samples were evaluated by the color difference equations’ under different illuminants. The results showed that yellow-blue color coordinates computed according to CIELAB and Hunter systems differed from each other at a great extent and color difference equations performed different from each other in the different hue zones of the CIELAB color space in accordance with the illuminants under which the computations were made. The highest color difference results were obtained according to CIELAB and the lowest color difference results were obtained according to CIEDE2000. Red and black hues had the highest, and blue and yellow hues had the lowest color difference results according to all formulae and illuminants.     

Reflectance prediction of colored polyester fabrics by a novel formula

This paper focuses on the reflectance prediction of colored (unicolored) fabrics considering relationship between fractional reflectance values and cover factors of fabrics woven from polyester yarns. A novel equation for the calculation of relation between fractional reflectance and cover factor was proposed and usage of the equation was assessed by reflectance measurements. 48 dyed polyester fabrics having different constructional parameters were used and fabrics differed from each other by their cover factors. Warp yarn type and count, warp density and warp yarn twist were the same but weft yarn count, weft yarn fiber count and weft density were different for the fabrics in experimental sub-groups. The reflectance measurements were conducted on the dyed fabric samples as well as on the individual yarn systems (warp and weft) of the same fabrics. The proposed equation was tested according to different fabric constructional parameters and reasonable results with the experimental data were obtained. The possibilities of general use of derived mathematical relations between theoretical and measured reflectance values were researched. The relation obtained was used to explain the effects of different constructional parameters on reflectance behavior of fabric surfaces.     

Comparison of some process components of polyester microfibre dyeing by using mathematical and experimental methods

In this paper, a comparison between a mathematical and an experimental method for the evaluation of some process components of polyester microfibre dyeing is presented. In the experimental part, a dyeing procedure was chosen, K/S values of the dyed samples were measured and the coefficients of the mathematical formula presented in the mathematical part were obtained. K/S values of different dyeing procedures were also measured. In the mathematical part, predicted K/S values were calculated by a novel formula. The results of the two methods were then compared. According to the results obtained, the mathematical formula presented in this study can be used for calculating the predicted K/S values at lower dye concentrations.     

Assessing the relationship among fabric constructional parameters, fractional reflectances and cover factors of polyester fabrics by experimental and mathematical methods

This paper focuses on the assessment of the relation among constructional properties, fractional reflectances and cover factors of fabrics woven from polyester yarns. A novel equation for the calculation of the relation between fractional reflectance and fabric cover factor was proposed and the usage of the equation was assessed by reflectance measurements. 48 polyester fabrics having different constructional parameters were used and the fabrics differed from each other by their cover factors. The warp yarn type and count, warp density and warp yarn twist were the same but weft yarn count, weft yarn fiber count and weft density were different for the fabrics in the experimental sub-groups. The reflectance measurements were conducted on the pretreated but undyed fabric samples as well as on the individual yarn systems of the same fabrics. Fabrics with the same cover factors exhibited different fractional reflectances. Reflectances were found to be dependent on the cover factor as well as on yarn fiber fineness, yarn count, yarn density and fabric weave. The changes in crimp of the yarns according to different construction parameters also governed the changes in fractional reflectances of fabric surfaces. The proposed equation was tested according to different fabric construction parameters and it was concluded that fiber fineness and weave pattern were among the most important parameters which govern the total light reflectances from the fabric surfaces, although they are not incorporated in the calculation of the fabric cover factors. The proposed equation was used to explain the effects of these components on the reflectance behavior of the fabric surfaces and on fabric cover.