EFFECT OF FINISHING COATS ON PHYSICAL ...

7th INTERNATIONAL CONFERENCE OF TEXTILE 10-11 November 2016, Tirana, ALBANIA

EFFECT OF FINISHING COATS ON PHYSICAL PROPERTIES OF GARMENT LEATHERS N. Örk 1, G. Kara1, K. C. Yilmaz1, E. Temel2, B. O. Bitlisli1 and A. C. Adigüzel Zengin1* 1

Ege University, Engineering Faculty, Leather Engineering Department, 35100, Bornova, Izmir, Turkey, 2 Ege University, Engineering Faculty, Textile Engineering Department, 35100, Bornova, Izmir, Turkey [email protected]

Keywords: Leather, comfort, finishing, coating, physical properties, drape-ability, stiffness

Abstract Comfort is explained with the physical properties of the wear products and the wear comfort can be described as satisfaction and feeling of a person in the wear material. For the leather products, finishing process is one of the important step affected the physical characteristics of the leathers. Also different finishing techniques and the number of the layers applied to leathers at finishing process lead to changes in the physical properties of the leather products. The aim of the study was to determine the effect of the finishing coats on the physical properties of the garment leathers in terms of drape-ability and stiffness properties. For this purpose, six crust chromium garment leathers were used for different type of finishing processes such as aniline, semi-aniline and pigmented. Two separate finishing coats were applied for each finishing type and the effect of the finishing layers on physical properties of the leathers were determined by the standards such as TS ISO 3801 - Determination of mass per unit length and mass per unit area, TS EN ISO 2589 - Determination of thickness, TS 9693 - Textiles the Assessment of Drape of Fabrics, ASTM D1388 - Standard test method for stiffness of fabrics. The finishing coat, applied in two separate layers, had a significant effect on the physical characteristics of the garment leathers. A decrease was obtained for the drape-ability and stiffness properties of the garment leathers depending on the finishing layers in contrast to increased grammage values.

Introduction Leather goods are manufactured from different types of hides and skins by a series of chemical and mechanical operations. The manufacturing, especially the finishing technology applied to leathers are selected depending on the product type, customer demand and fashion [1]. The products used in finishing applications ensure that all types of crust leathers can be converted into high-performance fashion leathers. By finishing applications, the usage possibilities of leather goods, physical properties of leathers like color tone and homogeneity, surface appearances, surface touch and some wear resistance properties will be improved. Also the 169


comfort properties of leather products could be directly affected by the finishing techniques applied to leathers. For the garment leather manufacturing, aniline, semi-aniline and pigmented finishing techniques are known as the commonly preferred applications. Leathers used for apparels need to carry out the required comfort and physical properties. Generally, the comfort properties are associated with softness, drape, and water vapor permeability [2]. Drape is defined as the deformation of a fabric produced by its own weight and is an important component of garment aesthetics [3]. It is a complex combination of fabric structural and mechanical properties such as stiffness, flexural rigidity, weight, thickness and etc. [4-6]. Stiffness is the parameter to evaluate the bending rigidity and handling of the fabric. The fiber material, yarn and fabric structure are effected the stiffness property of the product [7]. Although different studies have been found about fabric drape-ability and stiffness in literatures, up to date according to our knowledge, this is the only study describing the effect of different finishing applications and their coats on garment leathers. The aim of the study was to determine the effect of the finishing coats on the physical properties of the garment leathers in terms of drape-ability and stiffness properties. For this purpose, six crust chromium garment leathers were used for different type of finishing processes such as aniline, semi-aniline and pigmented. Two separate finishing coats were applied for each finishing type and the effect of the finishing layers on physical properties of the leathers were determined by the means of grammage, thickness, drape-ability and stiffness properties.

Materials In the study, six crust chromium garment leathers were used for the finishing applications. They were purchased from Tezcan Leather Company from Karacasu, Aydın, Turkey.

Methods Crust garment leathers were classified into three groups according to finishing techniques. Aniline, pigmented and semi aniline techniques that are frequently applied to garment leathers were selected for the finishing applications (Aniline-A, Pigmented-P and Semi Aniline-S). Prior to finishing processes, the measurements of thickness, grammage, drape-ability and stiffness were performed and subsequent to each finishing coat, same determinations were carried out for all the finishing techniques. Sampling of the leathers was performed according to TS EN ISO 2418 standard [8]. The test samples were conditioned in accordance with TS EN ISO 2419, at 23 ± 2°C temperature and 50% ± 5 relative humidity [9]. The thickness and grammage of the samples was measured according to TS EN ISO 2589 and TS ISO 3801 standards respectively [10-11]. Drape coefficient was determined using drape tester according to TS 9693 [12]. The drape coefficient was expressed as a percentage. A circular leather specimen of 30cm diameter was placed between two horizontal discs (18cm), and the unsupported annulus of leather was allowed 170


to hang down. The photos of the draped specimens were taken by a camera and the pixels of the photos were counted. The drape coefficient was calculated with the formula Eq. (1) as given below: Drape coefficient (DC %) = [(M - S) / (L - S)] x 100 M: Material Pixels Count, S: Small Diameter Pixels Count, L: Large Diameter Pixels Count Stiffness test was performed using digital pneumatic stiffness tester according to ASTM D1388 [13]. A plunger of 25.4 mm diameter pushed the fabric through a 38 mm diameter orifice for a distance of 57 mm in 1.7 seconds and the maximum forces were recorded.

Results The results of the grammage values are given in Table 1. The grammage values of aniline, pigmented and semi aniline finished leathers showed a slight difference after the finishing coats. The highest increase in weight was obtained from pigmented finishing technique compared to aniline and semi aniline finishing. The effect of the finishing coats on grammage values of final leathers seemed to be insignificant for the finishing types of garment leathers. Table 1. Effect of finishing coats on grammage values [g/m2] Crust [g/m2]

1. Coat [g/m2]

2. Coat [g/m2]

A

267.50

267.25

271.75

P

372.50

374.25

381.00

S

363.25

363.50

368.25

The thickness values of the finished leathers were found lower than the crust leathers due to the ironing process applied after each finishing coat (Table 2). Considering the thickness differences (0.02 mm) occurred between the first and second finishing coat, the finishing type was found effective due to the components used in the finishing recipes. No difference was determined for the aniline leathers and the leathers finished with aniline technique had the minimum thickness value. Table 2. Effect of finishing coats on thickness [mm] and drape-ability values [%] Crust

A P S

Thickness [mm] 0.6 0.74 0.74

Drape coefficient [%] 45.29 51.48 56.83

Thickness [mm] 0.52 0.65 0.6

1. Coat Drape coefficient [%] 51.43 60.36 71.05

Thickness [mm] 0.52 0.67 0.62

2. Coat Drape coefficient [%] 50.48 55.12 65.46

The drape-ability of the crust leathers were influenced from the finishing coats of the applications. Drape coefficient values were increased after the finishing applications which were the good sign of the firm handle of the leathers. Although drape coefficient values of second coats were found lower than the first coats, an increase was determined compared to crust leathers. This could be attributed to the increased grammage values of the leathers. Semi aniline 171


finishing type lead to less drape-ability leathers compared to pigmented and aniline finished ones. Table 3. Effect of finishing coats on thickness [mm] and stiffness values [N]

A P S

Crust Thickness Stiffness [mm] [N] 0.56 6.25 0.66 8.42 0.74 11.75

1. Coat Thickness Stiffness [mm] [N] 0.51 10.36 0.5 8.22 0.64 16.47

2. Coat Thickness Stiffness [mm] [N] 0.45 10.29 0.67 9 0.78 15.21

The stiffness values of the leathers finished with three different techniques are given in Table 3. The stiffness properties could be related to the softness of the leathers which is one of the important quality criteria of the garment leathers. The finishing type as well as the finishing chemicals is found to be effective on the softness of leathers according to the stiffness values obtained from the leathers given in Table 3. The stiffness values were increased after the finishing coats. The highest change was obtained after the first coat of the finishing’s and with the second coats the stiffness values were found nearly stable. Similar to drape-ability properties, semi aniline leathers had the highest stiffness values compared to other finishing types. Table 4. The correlation between the leather properties Properties Thickness Drape coefficient Thickness Grammage Thickness Stiffness Drape coefficient Grammage Drape coefficient Stiffness Grammage Stiffness

Correlation Values -0.98 -0.41 -0.99 0.2 0.94 0.53

The thickness-drape coefficient and the thickness-stiffness properties had a significant negative correlation and a consistent relation. The drape coefficient-stiffness properties had a significant correlation but no correlation was found between the drape coefficient and grammage properties (Table 4).

Conclusion In this study, the effect of the finishing coats on the physical properties of the garment leathers in terms of drape-ability and stiffness were determined in addition to grammage and thickness values. For this purpose, crust leathers were finished with three different finishing types such as aniline, semi-aniline and pigmented and the change between the two separate finishing coats were presented. The following conclusions have been drawn; 1.The finishing coats had no significant effect on the grammage values of the final leathers. 2.They had an impact role on the drape-ability and stiffness properties of the garment leathers. 3.Different finishing types resulted different drape-ability and stiffness values and semi aniline leathers had the highest values. 4.Lastly a correlation was determined between drape-ability and stiffness properties. 172


References [1] V. J. Sundar, J. Raghavarao, C. Muralidharan and A. B. Mandal: Recovery and Utilization of Chromium- Tanned Proteinous Wastes of Leather Making: A Review, Critical Reviews in Environmental Science and Technology, Volume 41 (2011), Issue 22, p. 2048-2075. [2] T. B. Sudha, P.Thanikaivelan, K. P. Aaron, K.Krishnaraj, B.Chandrasekaran: Comfort, Chemical, Mechanical, and Structural Properties of Natural and Synthetic Leathers Used for Apparel, Journal of Applied Polymer Science, Volume 114 (2009), p. 1761–1767. [3] G. E. Cusick: The Dependence of Fabric Drape on Bending and Shear Stiffness, Journal of Textile Institute, Volume 56(1965), p. 596-606. [4] J. Huand, Y.F.Chan: Effect of Fabric Mechanical Properties on Drape, Textile Research Journal, Volume 68(1998), Issue 1, p. 57-64. [5] S. H. Eryürük, F. Kalaoğlu, S. Kurşun Bahadir, C. Sariçam, S. Jevsnik: The Evaluation of Stiffness and Drape Behaviour of Wool Fabrics, Journal of Textiles and Engineer, Volume 22 (2015), Issue 98, p. 24-32. [6] E. Yıldız, N. Özdil: Subjective and Objective Evaluation of the Handle Properties of Shirt Fabric Fused With Different Woven, Tekstil ve Konfeksiyon, Volume 24 (2014), Issue 1, p. 47-55. [7] M. E. Yüksekkaya, T. Howard, S. Adanur: Influence of the Fabric Properties on Fabric Stiffness for the Industrial Fabrics, Tekstil ve Konfeksiyon, Volume 4 (2008), p. 263-267. [8] Turkish Standard Institute: TS EN ISO 2418 Leather - Chemical, physical and mechanical and fastness tests - Sampling location, (2006). [9] Turkish Standard Institute: TS EN ISO 2419 Leather - Physical and mechanical tests – Sample preparation and conditioning, (2012). [10] Turkish Standard Institute: TS EN ISO 2589 Leather - Physical and mechanical tests – Determination of thickness, (2016). [11] Turkish Standard Institute: TS ISO 3801 Textiles - Woven fabrics - Determination of mass per unit length and mass per unit area, (2015). [12] Turkish Standard Institute: TS 9693Textiles the Assessment of Drape of Fabrics, (1991). [13] ASTM International: ASTM D1388-14 Standard Test Method for Stiffness of Fabrics, (2014).

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