Influence of Fabric Structure Parameters on Seam Slippage

Edita Malčiauskienė, *Algirdas Milašius, Influence of Fabric Structure Parameters Rimvydas Milašius on Seam Slippage

Kaunas University of Technology, Abstract Department of Textile Technology The slippage resistance of yarns at the seam in woven fabrics is a very important factor Studentu Str. 56, LT-51424 Kaunas, Lithuania and very strict claims are made with respect to this property. It is necessary to know how E-mail: [email protected] the fabric structure influences seam slippage quality before manufacturing a fabric. The purpose of this work was to establish which of the fabric structure parameters influence *JSC „Drobė co“, seam slippage. Our previous work investigated the influence of weave on the seam slippage Draugystės str. 14, LT-51259, Kaunas, Lithuania characteristics of a fabric, and a new weave factor was proposed which best characterises the weave from the thread slippage point of view. It was found that the seam slippage influences not only the weave factor in the slip direction but also in the normal direction. In the paper, by means of the design of experiments, the influence of weave, warp density and weft density on seam slippage was investigated. It was found that the warp density has a very low influence on seam slippage characteristics. Only the weft density and weave influence seam slippage.

Key words: woven fabrics weave factor, seam slippage, fabric structure and density.

n Introduction This factor could not evaluate the differ The slippage resistance of yarns at a seam ence between types of weaves (it is well in woven fabrics is a very important fac- Creating new high quality textile prod- known that the following weaves: twill tor and very strict claims are made with ucts and analysing their properties is 7/1, 8 held satin and basket 4/4 have a respect to this property. It is an important an especially pressing and important different tightness, but are still counted parameter for fabric characterisation, es- problem today. When new fabrics are with the same value, F = 4) and unbal- pecially for garment making. Moreover designed it is important to know their anced weaves, whose average warp float it is necessary to know how the fabric various properties. It is well known that is different from the average weft float structure influences seam slippage qual- woven fabric quality is closely dependent (warp rib 4/4 and weft rib 4/4 behave ity before manufacturing a fabric. This on the structure of the fabric. Each fabric knowledge allows to design fabric with very differently during weaving but are is a complex material and its structure af- new patterns suitable for clothing that still evaluated using the same value, fects its own properties. A fabric’s struc- will not slip in its seams. Seam slippage F = 2.5). ture can be evaluated by seven basic pa- measures the ability of warp yarns to rameters: the warp and weft raw material, slip over the weft near the seam, which warp and weft linear densities, warp and Weave factor P offered by V. Milašius [1] extends in the warp direction, when the weft settings and the weave of the fabric is calculated directly from the weave ma- fabric is subjected to a given load in the [1]. All seven parameters of the fabric’s trix. Factor P evaluates not only a single weft direction (and vice versa). This load structure can be evaluated by integrated thread float, but an interlacing of adjacent is applied so as to separate the two pieces fabric structure factors. threads as well and can be calculated of the fabric joins by the seam, and thus for all types of weaves. Weave factor P an opening, which is the result of yarn Different researchers have proposed dif- measures the fabric structure, describing slippage, appears near the seam. Many ferent kinds of evaluation of all these some of its properties, such as its elas- studies have been performed on the slip- parameters. According to the ways and ticity and air permeability, among others page of yarns of woven fabric, but this methods of their evaluation, two groups [5]. On the other hand, although factor P question is still open [8 - 12]. The nnflu- of integrated factors are identified: those is very good for balanced weaves, it can- ence of the weave as well as the warp and based on Peirce’s theories and those not evaluate the difference between un- setting on the slippage of yarns of woven based on Brierley’s. These groups differ balanced weaves – warp rib 4/4 and weft fabric is not still completely investigated. in their physical meaning. In the first case rib 4/4 have the same value, P = 1.205. it is the ratio of the surface covered by Later on V. Milašius proposed factor P1, In previous works [13, 14] it was found threads to the whole fabric area. In the calculated in the warp direction. It cov- that the determination of models were second case, it is the ratio of the setting of few in this area, and because of that it ers most of the weaves used but cannot the ‘square’ analogue of a given fabric to was attempted to find a new weave factor be employed for calculating very unbal- that of standard ‘wire’ plain weave fabric which best characterises the fabric struc- anced weaves [6] (for example, plain [2, 3]. This group also includes the aver- ture from the thread slippage point of weave and weft rib 4/4 have the same age float length F, which was offered by view. Investigations with balanced weave Ashenhurst, and the weave factor P of- value, P1 = 1). Moreover it is known that fabrics showed that the new weave fac- fered by V. Milašius. the properties of fabrics with the same tor NPR better describes the influence of setting parameters but woven with not the weave on slippage than other known The average float length F was a very identical technological parameters are weave factors (V. Milašius’s factor P or simple and widely used factor [4]. How- different [7]. Therefore all fabrics need Ashenhurst’s factor F). According to ever, later it was observed that this fac- to be woven with the same loom. In this the coefficient of determination, it was tor didnot describe all the properties way, only the weight of fabric weaves as found that the power equation of the new -0.88 of a weave which are important from a well as the warp and weft setting can be weave factor (NPR2 ) characterises technological and end-use point of view. analysed. well a balanced fabric structure from the

98 Malčiauskienė E, Milašius A, Milašius R. Influence of Fabric Structure Parameters on Seam Slippage. FIBRES & TEXTILES in Eastern Europe 2012; 20, 3(92): 98-101. Table 1. Structural parameters of fabrics fering not only in the weave but also in used in the experiment. the warp and weft settings. They were all woven on the same rapier looms and S , S , Fabric Weave 1 2 K dm-1 dm-1 had the same linear density of warps and 1 twill 3/3 360 300 2.63 wefts – 12.5 tex×2. Other structural pa- 2 twill 2/1 300 278 1.43 rameters of the fabrics are presented in 1 2 3 4 5 3 twill 3/3 360 200 2.63 Table 1. The fabrics were woven in 5 dif- 4 plane weave 360 200 1.00 ferent weaves, which are shown in Fig- Figure 1. Weaves used for experiments: 5 twill 3/3 240 300 2.63 ure 1. 1 – diamond specular broken twill 2/3, 6 plane weave 240 270 1.00 2 – twill 2/1, 3 – twill 2/2, 4 – plane weave, diamond The slippage resistance of yarns at a seam 5 – twill 3/3. specular 7 300 225 2.55 broken twill in the woven fabrics was measured with 2/3 a tensile testing machine - Zwick/Z005, 8 plane weave 240 200 1.00 according to the international standard 1 9 360 250 1,84 ‘Determination of the slippage resistance 10 240 250 1,84 twill 2/2 of yarns at a seam in woven fabrics – Part 11 300 300 1,84 1: Fixed seam opening method’ (LST EN 2 12 300 200 1,84 ISO 13936-1: 2004) and according to the 13 twill 3/3 300 250 2,63 Woolmark test method (TM 117 ‘Seam Figure 2. Stitch type: 1- needle thread, 2 – 14 plane weave 300 250 1 bobbin thread. slippage of woven fabrics’) at 78 N force 15 twill 2/2 300 250 1,84 distance between yarns after the slippage had been measured. ∑ i NPR = (1) thread slippage point of view. It was es- R R tablished that for unbalanced weave fab- Pieces of the test fabric were sewn to- 1 2 rics, seam slippage influences not only gether using a type 301 stitch (see Fig- Where: ∑ i −is the sum of all threads the weave factor in the slip direction but ure 2). 100% core spun polyester of which resist slippage, R1 - warp repeat, also in the normal direction. Hence the 45 tex linear density was used for the R2 - weft repeat. influence of the weave factor in the slip seam, stitch density – 50 dm-1, and nee- and opposite directions was investigated dle size – 0.90 mm (according to Stand- This factor is calculated directly from the -0.88 -0.88 ard LST EN ISO 13936-1: 2004). The K = 0.81×NPR2 + 0.19×NPR1 ). weave matrix. test specimens were stretched until a The weave factor in the slip direction force of 200 N. Five specimens of each influences seam slippage by 81%, and The power equation of the new weave fabric were prepared for the tests. weave factor on opposite direction by factor shows a good correlation between the experimental and theoretical values: 19%. The analysis of the worsted fabrics’ characteristics showed that the warp yarns K = (NPR2-0.88) (2) The aim of the present work was to ana- always slip more over the weft and not lyse how the weave as well as the warp vice versa. Therefore, in this research Experimental results and weft settings together influence the only tests of seam slippage in the weft di- slippage resistance of yarns at a seam in rection were carried out (warp yarns slip- and discussions woven fabrics. ping over weft yarns). All results were All seven parameters of the fabric’s statistically processed. structure (the raw material of the warp n and weft, the linear density of the warp Materials and methods The new weave factor NPR [13] was cal- and weft, the warp and weft setting, and The objects of investigation were fifteen culated as the proportion of all threads the weave of the fabric) influence the wool fabrics, woven according to the resisting slippage in the warp and weft slippage resistance of yarns at a seam in theory of the design of experiments, dif- repeats Equation 1: woven fabrics. In order to establish the

25 25

20 20

15 15

R2 == 0,9673 0.9673 10 10

22 Experimental values Experimental Experimentas values Experimentas RR = = 0.95470,9547 5 5 Experimental values Experimental values

0 0 0 5 10 15 20 25 0 5 10 15 20 25 CalculatedCalculated values values CalculatedCalculated values values

Figure 3. Correlation between experimental and calculated values Figure 4. Correlation between experimental and calculated values of seam slippage. of seam slippage according to the simplified equation.

FIBRES & TEXTILES in Eastern Europe 2012, Vol. 20, No. 3 (92) 99 Table 2. Encoded structure parametervalues of fabrics and experimental slippage resist- Z = 5.86 - 0.25 X1 - 4.76 X2 + ance thereof. + 3.87 X3 - 2.75 X1× X2 + + 2.84 X × X - 1.23 X × X + X (S , X (S , Slippage resistance 1 3 2 3 Fabric Weave 1 1 2 2 X (K) dm-1) dm-1) 3 of fabric, mm - 1.82 X1² + 2.54 X2² - 0.71 X3² 1 twill 3/3 1 1 1 3.64 The equation obtained is informa- 2 twill 2/1 0 0.5 -1 2.76 tive because the Fisher criterion found 3 twill 3/3 1 -1 1 21.14 much more than the tabular: F =10.89, 4 plane weave 1 -1 -1 4.52 Ftabular = 4.64. It was also found that its 5 twill 3/3 -1 1 1 4.22 coefficient of determination is very high, 6 plane weave -1 0.4 -1 2.50 R2 = 0.9637 (Figure 3). 7 diamond specular broken twill 2/3 0 -0.5 0.9 10.54 In order to find the most informative and 8 plane weave -1 -1 -1 5.48 simpler equation, some elements which 9 twill 2/2 1 0 0 4.30 least influence seam slippage were elimi- 10 twill 2/2 -1 0 0 4.48 nated. As a result, a simpler equation with 11 twill 2/2 0 1 0 2.84 the maximum informative was found: 12 twill 2/2 0 -1 0 14.86 Z = 4.82 - 4.53 X + 3.56 X + 13 twill 3/3 0 0 1 10.24 2 3 - 4.01 X2 × X3 + 3.77 X2² 14 plane weave 0 0 -1 2.14 15 twill 2/2 0 0 0 4.18 Fisher criterion F = 15.61, Ftabular = 2.86. Coefficient of determination R2 = 0.9547 (Figure 4). It shows a good correlation between the experimental and theoretical 0-5 5-10 10-15 15-20 20-25 values.

Analysis of this equation showed that the 25 warp setting parameters have no suffi-

20 cient influence on the slippage resistance of yarns at a seam in woven fabrics. The calculated values 15 weave of a fabric and weft setting param- of seam slippage, eters have a more substantial influence on mm 10 the slippage resistance of yarns at a seam in woven fabrics and must be taken in ac- 5 count while designing fabrics in order to 1 0 achieve the level of seam slippage nec-

-1 encoded weave

0 essary. The influence of both sufficient

-0,5 factor values X3

-0,75 -1 1 0,5 -0,25

0,25 parameters (weave and weft setting) on 0,75 seam slippage is presented in Figure 5. encoded weft setting values X2 It was also found that seam slippage has a linear dependence on weft setting pa- Figure 5. Influence of both sufficient parameters (weave and weft setting) on seam slip- rameters and a second order polynomial page. on the weave. As is seen from Figure 5, the influences of both parameters are so- influence of the fabric weave as well as slightly modified because there were phisticated. The greatest influence of the the warp and weft settings on the slip- some non- technological points, which weave exists for fabrics with a lower weft page resistance of yarns at a seam in were moved to the center of the plan. Ac- setting, while the influence of the weft woven fabrics, tensile tests were carried cording this plan, all values marked with setting increases with a decreasing in the out using fabrics with different weaves encoded values range from -1 to +1. All weave factor. and setting parameters. The raw material these encoded values of the fabrics and of the warp and weft was the same for their experimental slippage resistance are n all fabrics, hence its influence was not Conclusions presented in Table 2. analysed. The study was carried out with n Warp setting parameters do not have loomstate fabrics in order to avoid the in- a sufficient influence on the slippage Thus an experimental matrix was devel- fluence of finishing parameters. resistance of yarns at a seam in woven oped with elements which were inter- fabrics. 3 parameters were chosen (weave – plane esting. The expanded matrix obtained n The weave of fabric and weft setting weave and some popular twills (Fig- aproximated an equation of polynomial parameters have a substantial influ- ure 1); the warp setting ranged from 240 character of second order and next the ence on the slippage resistance of to 360 dm-1, and the weft setting – from coefficients were calculated by the least yarns at a seam in woven fabrics and 200 to 300 dm-1) and an experimental squares method. As a result, the follow- can be described by a two factor poly- plan was made by Box. This plan was ing seam slippage equation was found: nomial of second order.

100 FIBRES & TEXTILES in Eastern Europe 2012, Vol. 20, No. 3 (92) n The greatest influence of the weave exists for fabrics with a lower weft Technical University of Łódź setting, while the influence of the weft setting increases with a decreasing in Faculty of Material Technologies the weave factor. and Textile Design

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Received 02.11.2011 Reviewed 13.02.2012

FIBRES & TEXTILES in Eastern Europe 2012, Vol. 20, No. 3 (92) 101