Nowadays, elastan blended fabrics are widely produced as they provide comfort with their elasticity. However, problems may be encountered in dyeing elastane in these kind of fabrics. Elastan does not absorb the same amount of the dyestuff as the other fiber in the blends, slightly dyes or the dyestuff on it is separated in a way and effects the fastness properties of the fabric. Mechanical problems often occur in elastane during seam and usage [1-4].
Considering all these problems in production, giving elastane effect to fabrics without elastane with an innovative functional finishing agent application can be evaluated as an alternative production method.
Throughout this work, single jersey knitted fabric with a weight of 142 g/m2 produced from Nm 51, 100% polyester yarn was used. The fabrics were dyed with C.I. Disperse Red 92 and DENSOFT 185 (Denge Chemistry) was applied to give elastane effect. DENSOFT 185 is an innovative finishing agent that can be applied by exhaustion and impregnation methods in order to give elastane effect to woven and knitted fabrics of polyester, cotton, silk, cahmere and cotton/polyester blends. It can also be applied together with dirtrepellent finishing agents by impregnation methods. This finishing agent was applied to dyed knitted fabrics at different concentrations according to the exhaustion (1,3,5 %) and impregnation (20,40, 69g/L) methods. The treated fabrics were finally evaluated by colour differences, washing/rubbing fastness properties, bursting strength, pilling and handle properties (subjective evaluation). Fabric performances were determined according to the test results.
The reflectance values of the treated fabrics were measured by Datacolor Spectraflash SF 600+ instrument with specular mode and LAV (30 mm) viewing aperture. The colour values of the fabrics were calculated with D65 illuminant/10° observer values. The non-finished
dyed fabrics were taken as ‘standard’. The CMC 2:1 Formula was used to express the colour differences. The colour differences (CMC 2:1) results are presented in Figure 1.
All colour differences are at acceptable (<1) values. The washing and rubbing fastness tests are carried out in accordance with methods described in ISO 105-C06 (A1S test conditions) and ISO 105-X12:2000, respectively.There are no important effects on the
washing and rubbing fastness properties of the fabric samples. The bursting strength test results performed according to ISO 13938-2:1999 ve ISO 13934-1:2002 standards are summarized in Figure 2. When the bursting strength test results in Figure 2 are evaluated in
general, there is a decrease in the bursting resistance at acceptable rates with the increase in concentration of the finishing agent applied to knitted fabrics.
According to ISO 12945-2:2002 Textiles-Determination of Fabric Propensity to Surface Fuzzing and to Pilling-Part 2: Modified Martindale Method, an improvement in pilling tendency of fabrics occured with the increase in concentration. While the pilling test result of the unfinished fabric was 2, this value increased to 3 after the fihinshing application. According to AATCC Evaluation Procedure 5:2006 Fabric Hand: Subjective Evaluation standard, unfinished, finished and contains 5% elastane fabric samples were evaluated by 13 people. Fabric samples were assorted from stretch to non-stretch.
The increase in the concentration of the finishing agent has brought the elasticity of the fabric closer to the fabric sontaining elastane. All these results show that polyester knitted fabrics without elastane can be given a property as if they were elastane with functional finishing processes.
Prof. Dr. Burcu Yılmaz Şahinbaşkan
Marmara Üniversitesi, Tekstil Mühendisliği Bölümü