Evaluation of change in color of denim fabric after various


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Evaluation of change in color of denim fabric after various

  1. 1. Evaluation of change in color of denim fabric after various Industrial washing processes with different fiber composition Mushtaq. Mushtaq Mangat1 , J. Wiener 1 and A. M. Rehan Abbasi1,2 *corresponding author: mushtaq.mangat@gmail.com Abstract: Traditional denim made by using 100% cotton and novel denim made by using cotton in warp and spun PP in the weft were treated in 11 different ways on industrial garment washing machines with the help of various textile auxiliaries and pumice. There is an obvious change in color of denim. This change was measured by using Spectrophotometer. Reflectance was taken as a variable to observe the intensity of change. Color difference was measured by using the CIELab color difference formula 1976. Color space coordinates (L*, a*, b*) and color difference ΔE were calculated between the untreated denim and treated denim. 1. INTRODUCTION Majority of the denim clothing is passed through a washing process. Primary goal of this washing is to give a faded look and certain hand feel, which is a key factor in the marketing of denim clothing [1]. There are a number of methods and textile auxiliaries available to have a better look and hand feel. The whole process can be divided into three main areas: 1. Desizing and rinsing to remove the sizes applied during weaving 2. Change of color for faded look with the help of bleaching agent and enzymes 3. Application of softener for certain hand feel The whole process modifies the denim surface since some textile auxiliaries are deposited on the surface. This modification leads towards the change in the color. Color is a function of the reflectance and reflectance depends upon the physical and chemical structure of the substance. Selection of textile auxiliaries and process depends upon the final requirement of the customer. There is a lack in the evaluation of color changes due to different washing process. The common practice is to use previous references and hit and trial methods to have required results. In this study, color changes due to most commonly industrial washing process has been measured with the help of the spectrophotometer. This technique may help in prediction of the color changes due to a certain washing process. There is a drastic change in the physical properties due to industrial washing have been observed. Most commonly changes have been achieved by using oxidizing agents [2]. Militky and Bajzík have studied the impact of washing on certain properties of fabric and found significance changes due to washing [3]. 2. METHODOLOGY 1 Technical University of Liberec, Faculty of Textile Engineering; Studentská 2, Liberec 46117, Czech Republic 2 BUITEMS, Department of Textile Engineering, Quetta, Pakistan
  2. 2. Two types of denim fabrics were prepared for experiment; one contains cotton as warp yarn and spun polypropylene weft and other contains cotton in both warp and weft. These two denims were treated with different textile auxiliaries and stones. However, one sample was kept as standard to use for the measurement of changes. Detail of denim samples is given in Table 01 and 02. All washings were carried out in a mini clothing washing machine. Table 1: Traditional and Novel Denim Description Description Novel Denim Traditional Denim Warp Yarn Cotton Dyed, Tex 49.25 Cotton Dyed, Tex 49.25 Weft Yarn Spun PP Textile 54.0 Cotton Tex 49.0 Weave Twill 3/1 Z Twill 3/1 Z gram per sq. meter (GSM) 234 248 Table 2:Washing processes applied on denim substrate S# Desized Rinsed Treated with Enzymes Bleached with H2O2 Application of Silicone Softener Applied Quick dry Chemical Applied Cationic Softener Faded with Pumice Stone Application of Water Repellant Peached 1W O O 2W O O 3W O O O 4W O O O 5W O O 6W O O O 7W O O O 8W O O O 9W O O O O 10W O O O 11W O O O All samples were tested in Spectrophotometer (Data Color Spectra flash) using light source D65 and 10° observer. ΔE CIE 1976 L*a*b* equations was used. (1) Where
  3. 3. 3. RESULTS and DISCUSSION Table 3 consists of values of the color difference between washed & unwashed denim fabric specimens. Table 1 Color difference measurements of washed samples with unwashed sample Washing Ref Washing Detail Novel Denim ΔL* Δa* Δb* ΔE Traditional Denim ΔL* Δa* Δb* ΔE W1 Desized and rinsed 1PP -1.44 0.01 0.22 1.45 1COT -2.79 0.60 -1.54 3.24 W2 Desized and treated with enzymes 2PP -1.17 -0.09 0.24 1.20 2COT -2.38 0.48 -1.67 2.95 W3 Desized, ,treated with enzymes and bleached 3PP 7.39 0.15 3.67 8.25 3COT 6.07 0.39 2.47 6.57 W4 Desized, bleached and applied silicone softener 4PP 10.50 0.25 6.10 12.14 4COT 7.42 0.76 4.60 8.76 W5 Desized and bleached 5PP 4.11 0.42 3.07 5.15 5COT 2.02 0.55 2.07 2.94 W6 Desized, bleached and applied quick dry auxiliary 6PP 5.02 0.34 4.16 6.53 6COT 1.97 0.46 2.46 3.19 W7 Desized, bleached and applied cationic softener 7PP 6.90 0.44 3.59 7.79 7COT 5.52 0.44 2.46 6.06 W8 Desized, enzyme and stone washed 8PP -0.40 -0.05 -0.05 0.41 8COT -2.94 0.06 -0.44 2.97 W9 Desized, bleached, enzyme and stone washed 9PP 14.89 0.29 5.86 16.00 9COT 11.34 0.66 4.50 12.22 W10 Desized, bleached and application of water repellant auxiliary 10PP 4.87 0.47 3.32 5.91 10COT 3.29 0.53 2.27 4.03 W11 Desized, rinsed and peached 11PP -1.21 0.16 -0.09 1.22 11COT -1.95 0.16 0.22 1.97 Following conclusion can be derived from Table 3: 1. There is a significant change in the color from the standard in all cases. 2. There is a high correlation between novel and traditional denim in L* (0.99) and b* (0.96) and E (0.93). However, in case of a*, correlation is not strong (0.37). 3. Table 3 depicts that there is a drastic change in ∆E when the sample is desized and treated with enzymes. Nevertheless, this change is significant when the sample is treated bleached. 4. In most of the cases the trend of change is similar. Only difference is in intensity of change. There is a significant change in the color from the standard after all washing processes. From the Figures 1 and 2, it can be observed that W4 (desized, bleached and applied silicone softener) and W9 (desized, bleached, enzyme and stone washed) made a significant influence compared to other industrial washes, on the color of both the denim samples regardless their structures. Samples have shifted much more towards orange hue with increased lightness. This phenomenon causes a major effect on CIE DE value. It also can be seen that with some washes like W1, W2, W8 and W11, the change in color is almost negligible.
  4. 4. Figure 1: Evaluation of washed Novel denim samples in Da-Db and DL plans compared to untreated sample Figure 2: Evaluation of washed Traditional denim samples in Da-Db and DL plans compared to untreated sample 4. CONCLUSION Two different denims which have been produced by using two different weft yarns show variation in reflectance after passing through different washing process. CIE Lab parameters and Δ E were selected to do a comparison. Nevertheless, in case of value a*, there is a significant difference and correlation is quite low. Furthermore, study concludes that major variation is linked with bleaching process, whereas, enzyme treatment makes an insignificant changes. Moreover, stone washing creates moderate variation in color. This work provides a guideline to denim manufacturers during the finalization of washing process. References [1] Mazumder, S., Effects of Sand Blasting With Industrial Enzyme Silicon Wash on Denim Apparel Characteristics. Daffodil International University Journal of Science and Technology, 2010. 5(1): pp. 6-9. [2] Montazer, M. and A.S. Maryan, A Comparative Study of Different Stone and Bio-stone Washing of Denim. 2010, dspace.lib.fcu.edu.tw. [3] Militky, J. and V. Bajzík, Influence of Washing/Ironing Cycles on Selected Properties of Cotton Type Weaves. International Journal of clothing Science and Technology. 1997. 9(3): pp. 193-199. [4] Agudelo, C., et al., Fabric Color Changes in Polyester Micro-fibers Caused by the Multiple Reuse of Dispersed-dyes Dye Baths: Part 1.Textile Research Journal, 2008.78(12): pp. 1041– 1047. [5] Alpay, H.R., B. Becerir, and M. Akgun, Assessing Reflectance and Color Differences of Cotton Fabrics after Abrasion.Textile Research Journal, 2005.75(4): pp. 357-361.