EVALUATION OF EFFECT OF FINISHING PROCESS ON THE COTTON FABRIC SURFACE PROPERTIES USING IMAGE ANALYSIS

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1 EVALUATION OF EFFECT OF FINISHING PROCESS ON THE COTTON FABRIC SURFACE PROPERTIES USING IMAGE ANALYSIS Dariush Semnani*, Mohammad Sheikhzadeh, Mehdi Gholipour Baradari, Ata Shahanaghi and Ahmad Ali Mehdizadeh Ardakani Department of Textile Engineering, Isfahan University of Technology, Isfahan, Iran HYPERLINK ABSTRACT: The finishing process of cotton woven fabrics is very important in their surface appearance. The amount of hairs and fibre pills on the fabric surface is changed during finishing process. Therefore, it is useful to investigate the deviation of surface appearance during different finishing conditions [1, 2, 3 and 4]. Many researchers have been used image processing techniques to analyze the surface of woven fabrics for pile or hair detection [5, 6 and 7]. Also, there are several methods for surface regularity measurement for woven fabrics of cotton or cotton/manmade fibres [8, 9 and 10]. This paper provides a method of image analysis to study the effect of finishing process on the cotton fabric surface properties. Fabric background was considered in black shade. Therefore, separating fibres from pills was possible. This method can be applied to categorized the pills fabric faults and to evaluate the surface properties. Finishing process including singeing, desizing, mercerizing, bleaching, dying and ironing had been carried out on cotton fabric samples. After each finishing stage, the surface of fabric was pictured and the amount of faults and pills will be defined by sample image analysis. Results showed that each finishing stage has its own effect on the surface structure of fabric. As it has been shown in Table 1 hairs percentage was changed after each stage of finishing process. Based on results, mercerizing was preferred than bleaching with hydrogen peroxide 1%. It should be noted that dyeing and ironing have great effect on decreasing the amount of fuzzes on the fabric surface. Because of the capability of defining the fuzzes between weft and warp in this image process algorithm, it was considered as the most effective and fastest one to examine the surface properties changes. Keywords: Cotton fabric, Finishing, Image analysis, Surface properties. INTRODUCTION: Textile finishing means all the operations that function on the fabrics after producing to improve the fabric surface properties. This stage are carried out on textile products (staple, sliver or tops, yarns or filaments, woven or knitted fabrics) to enhance their basic characteristics such as dye penetration, printability, wet ability, color, hand, and its appearance [1]. Cotton fabrics need more stages than other fabrics to be finished [2], because of necessity to improvement of surface prosperities particular scale of fabric fuzzes. Due to fibrillation of cotton fibres, cotton fabrics have sketchy fuzz with several lengths. These fuzzes cause some color unsteadies of fabric during dying process. Surface fuzzes due to various mechanical process and abrasion segregated from fabric while using and like bullet of fiber that decrease the objective quality of fabrics [3]. To prevent the bullet creation, several finishing process uses such as singeing and to avoidance of fuzziness and improve the surface properties like better glossiness and whitest face before dying process or sewing, mercerizing and bleaching on fabric is done. Ironing creates monotonous face in fabric and removal wrinkle and so sketchy fuzzes moved into fabric to pure fabric surface deformation. Heretofore, some deferent acts were done to reach the optimum term of finishing process, but none of them was

2 not effective in finishing process on the exterior properties of fabric and fuzzes difference on fabric surface especially [5,6]. Also some researches were done to measure the fuzziness on fabric with wavelet analysis and Fourier transformation. These methods are so complicated and can not show the exact scale of fuzzes on the fabric surface [7-10]. In the other studies, automatic optic systems were used to specification and evaluation fabric defects that in this method, fabric surface evaluation has been based on the texture defect and the effect of fuzzes is not distinct. This research is traced on a new method of image analyzing on the fabric surface to measure fabric fuzziness statistically. Then with determine the fabric fuzziness before and after each finishing processes, total effect of them scrutinized. EXPERIMENTS: In this research to survey of finishing processes (Singeing, Desizing and Bleaching, Mercerizing, bleaching, dying and ironing) on the surface properties of cotton fabric with image analyzing cotton fabric with mean length amount 1.12 Cm, Ne:20/2 and plain fabric that normal fabric in wear industrials was prepared as raw sample. Also finishing stages on the fabric was done and has been imaged after each stage. Finishing stages often includes singeing, desizing, mercerizing, bleaching, dying and ironing. With singeing treatment, fuzzes and fiber ends are burnt off in order highlight the fabric weave. It is generally carried out on gray pieces and the residues are removed by a further washing process. An oxidizing flame, which does not leave any trace of sooty residue on fibers, is used to carry out this operation. The flame can be perpendicular to the fabric, and only rarely tangential; the fabric is positioned at a distance of 2 mm from the end of the flame and the machine is equipped with a suction device under the fabric, which attracts the flame and concentrates the heat on the fabric. The fabric speed range 72 meters per minute in the monoforts signing with perpendicular flame machine model Figure 1: The machine used for singeing Desizing is carried out on woven fabrics to remove the sizing substance from the warp. The size must be totally eliminated since the fabric must absorb the liquor of subsequent processes homogeneously. For desizing have four method (enzymatic desizing, cellulose, destruction and oxidizing desizing). The fastest and best quality method picked, nee oxidizing desizing with Hydrogen peroxide. Fabric saturated in H2O2 1-2 volume that contain 7-15 gram per litter sodium hydroxide and vaporized for min up to disizing done a little bleaching. Bleaching treatments are applied to eliminate any impurity and obtain a pure white tone, to prepare substrates for low-density dyes or prints and to level off undesired tone variations. Bleaching agents mainly used for cellulosic fibers are sodium hypochlorite and hydrogen peroxide. With hydrogen peroxide, in the presence of alkali, little motes can be eliminated and the autoclave scouring can therefore be avoided. Bleaching was done with two solutions in the 75 C and 1.5 hours as Table 1. Table 1: Materials and their process in bleaching solutions Hydrogen peroxide Sodium silicate Sodium carbonate sodium hydroxide materials Oxidant and basic create tampon Resistance bleacher sphere to pat PH activator Process Solution 1% 1.6 ml/l 0.4 gr/l 0.4 gr/l Solution 1 Solution 3% 1.6 ml/l 0.4 gr/l 0.4 gr/l Solution 2 Mercerizing is a typical treatment for cotton yarns and fabrics, which improves the fabric luster and wet ability, ensures a covering effect for dead cotton, and improves dimensional stability and dyeing efficiency. This treatment is carried out using caustic soda (28-30 Bé), which determines the contraction and swelling of the fibers; they become translucent and increase their tensile strength, but reduce their flexural and torsion strength. The bean-like section of the fiber, becomes first elliptic and then circular, allowing a better reflection of light with a consequent increase of luster. The treatment is usually carried out under tension, with caustic soda at Bé (approx g/l).

3 The sodium hydroxide concentration is brought down to approximately 4 Bé by means of a circular shower. The fabric is then washed, neutralized and rinsed. To purvey two sample sign (with tension and without tension). At first in Ambienttemeperature samples relevant in solution(300gr/lit NaOH) for 10 min. then next stage done: washing fabric to remove slab from fabric, washing samples with water in C, laundering samples with Acetic acid 10%, then samples rinsed and dried in stenter (80 C) with no tensions. To dye fabric the color need used that have not any influence in image analysis method.the fabric put into the bat in 40 C and temperature was increased slowly until approaching to boiling point and it located in boiling condition for 40 minutes and then rinsed and ironed. IMAGE PROCESSING METHOD: Image analyzing was based on light reflection in different points of picture. If fabric sorted in three zones, background was dark, weft and warp yarns reflected all the lights, fabric fuzzes which prevalence part of light glowed that darker than yarn, with this theme, this sectors was separated. To reach this matter the limits of each part should be determined to gain their percentage. Images prepared with scanner with 600 dpi in gray scale. To determine the limits of each part of images, histogram of Figure 2 that like t-distribution was used. In a t- distribution " EMBED Equation.3 " that EMBED Equation.3 is average and EMBED Equation.3 is standard deviation, usually presents the ratio of upper limit of point plenty in 95% probability, as per histogram semblance with t- distribution and also the tendency of curve to the white points, 95% limit probability confine was used to find the threshold limit. Figure 2: A sample for fabric image histogram Experiments were showed that standard deviation for two parts of light and dark points was not equal, so as per divided standard deviation method, half of standard deviation was selected for light points (equal to " EMBED Equation.3 "). In fact the value of " EMBED Equation.3 ", was added to threshold limit. In histogram from 0 to EMBED Equation.3 proper to background and from EMBED Equation.3 to EMBED Equation.3 with rather lightness than last confine, proper to fuzzes and after EMBED Equation.3 proper to weft and warp yarn bodies. Histogram shows that white point plurality is greater than gray and black points. Threshold limits like 1 and 2 equation. EMBED Equation.3 (1) EMBED Equation.3 (2) To use this threshold, weft and warp yarns bodies and image background that upper and downer gray scale elapsed. So remained images were the complex of fuzzes gray scale reeducated to binary. Density of short, medium and long fuzzes was computed. Density of spots identified for yarn bodies and fuzzes in image determined as below: EMBED Equation.3 (3) EMBED Equation.3 (4) In equations 3 and 4 signs EMBED Equation.3 EMBED Equation.3 EMBED Equation.3 EMBED Equation.3 و EMBED Equation.3 are fuzz to all image percentage, fuzz to yarn bodies percentage, spot in fuzz image, spot in body image (upper than T2) and total points of image. With calculate the image density from equations 2 and 3 for samples after each finishing process, fuzzes change were studied. RESULTS: Finishing samples that prepared in 30 parts, analyzed after each finishing stage. Results are shown in Table 2. Table 2: Results of sample analyzing after each finishing stage Fuzz percent to yarn buddy percent Fuzz percent to total image processes Raw fabric

4 Raw fabric Signing Desizing and bleaching with solution 1% Desizing and bleaching with solution 3% Mercerizing Bleaching Dying and ironing Results present that singeing has a small affects but this logic is not correct because during singeing, the fuzzes that are out of fabric surface removed and with 2D image this issue is not clear. They will be recognizable after dying. Fabrics with no singeing treatment have chromatic point on its face, because surface fuzzes after dying appeared chromatic but for singeing fabrics tedium surface after dying could be reached. In desizing and bleaching stages attend to Table 2 and three histogram charts of Figure 3 these points could be presented. Results in Table 2 showed that fuzzes percentage will be decreased, so ratio of fuzzes to yarn bodies was reduced and points that diffuse light have been minus so fabric was viewed lighter. Histogram charts of Figure 3 showed that the mean points of solution 3% rather than solution 1%, as per these charts, using triple times of materials is not advantaged. So in bleaching, solution 1% proposed that with standard method accordance (With gain quality and economical advantage). But this matter is not a point and with structure of yarn and texture this measures rather or lesser that must survive. SHAPE \* MERGEFORMAT Figure 3: Fabric image point s histogram (a: after bleaching with solution 3% b: after singeing and c: after bleaching with solution 1%) In mercerizing and bleaching according to the results, bleaching provides a better effect than mercerizing. In bleaching, fabric density almost changes and because of fiber swelling in tensionless process, fabric empty holes were covered and made the results unreal. Bleaching and mercerizing histograms Figure 4 shows that with mercerizing, fabric will be lighter. In mercerizing chart Figure 4b light points are more than bleaching processes Figure 4a. Also this histogram shows that background points in bleaching decreased. Therefore in this stage mercerizing method was selected but in the instances of need to absorb more water, bleaching will be chosen. These stages depend on fabric usage. However a light dye was used but fabric luster decreased, the points with complete luster does not exist, so in this stage a plenty of points that are depended to yarn body fuzzes, attended joint together and won't separable with this algorithm. This system acts like eye and can not recognize the defects and fuzzes after dying. In fact, dying process does not have any efficacy on the fabric surface. In ironing hairs surface and yarn bodies will be flatten and reflect the light more and fabric face views lighter. SHAPE \* MERGEFORMAT Figure 4: Fabric image points histogram (a: after bleaching b: after mercerizing) According to Figure5, about the solution percentage, rate of charts when solution1% was used determined and in solution3% this value is equal to However the better result was gained with solution 3% but solution1% was chosen due to material costs because the rates are not too different. Another object could be gained from Figure 5 and Table 3 is that which stage has most effect in fabric surface quality improvement. In fact, singeing removes the surface fuzzes and reduces hairs. Desizing and bleaching clean the burned hair from fabric surface and in fact hairs reduce than previous stage. Ironing and dying have a great rule but with this results are not closed to real because of dying, light reflection per fuzzes and yarn bodies will be closed and sometimes they joint together.

5 Figure 5: Finishing stages effect on fabric fuzziness CONCLUSION: Finishing processes on fabrics is a method to improve fabric face and quality. Also ranking of these processes have a great importance. According to results, it is not fine to omit any stages to money saving or reduce them while acting. Finishing processes, such as singeing, mercerizing, bleaching, dying and ironing were done on the fabric sample. After each stage fabric surface scanned and with analyzing the fabric images, fuzzes and defects were measured. Results showed that all finishing processes are effective on fabric surface structure and none of them should be ignored. In act, solution 1% H2O2 was chosen for bleaching, also mercerizing was preferred to bleaching. Dying and ironing have great effects; to show lessens of fabric surface fuzzes. Finishing processes improve fabric surface and decrease the fuzzes. Image processing algorithm used in this research is very quick and valid method to study the fabric surface properties. REFERENCE: [1] Hall A.B., Textile finishing, 1966, 3 rd Edition, Heywood, American Elsevier, US. [2] Ali, S.I., Khanum, A. and Ahmed, E., "Fabric handle characteristics of cotton fabrics" Journal of the Textile Institute, 85(1), 22-23, [3] Kumar P.S.M, Cotton textile industry, 1997, Reliance Pub. House, India. [4] Evans M., " Mechanical finishing", American Dyestuff Reporter, 71(5), 36-41, [5] Cheek L., Wilcock A., and Hsu L.H., "Effects of Mercerization, Sub mercerization, and Liquid Ammonia on Fiber Morphology of Neps in Cotton Fabric", Textile Research Journal, 57(12), , [6] Sakaguchi A., Kim H., Matsumoto Y.I. and Toriumi K., "Woven Fabric Quality Evaluation Using Image Analysis", Textile Research Journal, 70(11), , [7] His C.H., Bresee R.R. and Annis P.A., "Characterizing Fuzz on Fabrics Using Image Analysis", Textile Research Journal, 70(10), , [8] Kang T.J., Kim S.C., Sul I.H., Youn J.R., and Chung K., "Fabric Surface Roughness Evaluation Using Wavelet-Fractal Method: Part I: Wrinkle, Smoothness and Seam Pucker", Textile Research Journal, 75(11), , [9] Kang T.J., Kim S.C., Sul I.H., Youn J.R., and Chung K., "Fabric Surface Roughness Evaluation Using Wavelet-Fractal Method: Part II: Fabric Pilling Evaluation", Textile Research Journal, 75(11), , [10] Palmer S. and Wang X., "Evaluating the Robustness of Objective Pilling Classification with the Two- Dimensional Discrete Wavelet Transform", Textile Research Journal, 74(2), , (c) (b) (a) (a) (b)

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