CHAPTER 9 DEPENDENCE OF WICKABILITY ON VARIOUS INTEGRATED FABRIC FIRMNESS FACTORS

Transcription

1 92 CHAPTER 9 DEPENDENCE OF WICKABILITY ON VARIOUS INTEGRATED FABRIC FIRMNESS FACTORS 9.1 INTRODUCTION The present work deals with the dependence of fabric structure on the wickability of technical assignment fabrics on various parameters of fabric structure. It has been established that, although fabric wickability depends on weft density and weave factor P1, it is possible to achieve the same wickability of different fabrics by keeping fabric integrated firmness factor constant and varying the pick density that should be used in each weave. The wickability of fabric is one of the very important properties of comfort of fabrics. The wickability depends on shape and value of the pores and the inter thread channels, which are dependent on the structural parameters of the fabric. The main structural parameters, which have most influence on fabric wickability are pick density and linear densities of yarns and weave. Earlier it was established that wickability was dependent on weave and pick density of fabrics in particular. While designing fabrics and analyzing their properties, it is appropriate to be guided by one integrating factor.

2 93 Peirce (1937) particularly precisely disclosed the meaning of integrating fabric structure factor: It gives a very suitable basis of comparison for any experimental investigation, not only of cover but also of hardness, crimp, permeability and transparency, limits of picking, etc., in which fabrics of similar cover factors show similarity. The fabric firmness factor can also be used for the prediction of wickability of fabrics. Milašius (2) proposed a new integrating fabric firmness factor that can be calculated by equation (9.1) T 1 T / T 1, P 1 2/3 avg /3 1 2/ 3 T / T T / T S S1 (9.1) where T 1 - warp linear density, T 2 - weft linear density, T avg. - average linear density of the woven fabric thread, P 1 - Milašius weave factor, - raw material density, S 1 - Ends/cm of the woven fabric, S 2 - of the woven fabric. The value of the integrated fabric structure factor can vary from to 1 depending on the density of the fabric structure, i.e. with an increase in the density of the fabric structure; the factor approaches the value 1. The present investigation focuses on the possibility of designing fabrics on the basis of integrated firmness factor and a comparison of various integrated firmness factors on wickability has been done.

3 MATERIALS AND METHODS Firstly, the fabrics, woven with projectile desk loom of polyester/ viscose blend 65/35, 19.5 tex, 2 ply, warp density 23.6 ends/cm, weft density 23.6 picks/cm, were used. Eight different weaves were employed as shown in Figure 9.1. The weaves were chosen in such a way, that they could be woven with the same loom setting. The weave factor P1 of all chosen weaves was changed to the widest possible range (from 1 to 1.88). The wicking tests were carried out by MPVWT in weft direction as discussed in Chapter 4. Figure 9.1 Eight types of structure A1 plain weave; A3 warp rib; A4 twill 2/2; A5 weft direction Bedford cord; A6 fancy twill ; A 7 sateen; A8 basket weave ; A1 crape weave;

4 95 Secondly, the experimental investigations establishing the dependence of fabric wickability on their weft density were carried out with 8 fabrics of different weave structures as shown in Table 9.1. The calculated weft density for the 8 different fabrics, when ranges from. to.5, are given in Table 9.1. A total of 24 fabrics were prepared. The wicking test was carried out by MPVWT weft direction as discussed in Chapter 4. Table 9.1 Values of calculated weft density S 2 when is constant Fabric Code P1 Weave factor S 2 =.5 S 2 =. S 2 A A A A A A A A =. 9.3 RESULTS AND DISCUSSIONS Effect of P1, on Wicking when Warp and Weft Density are Constant Table 9.2 shows the vertical wicking results, in the weft way at constant values of S 1 and S 2 for eight weaves together with the corresponding P1 weave factor and integrated firmness factor. In this case, the weft and warp densities were kept at 23.6threads/cm.

5 96 Table 9.2 Values of wicking for eight types of fabrics Fabric Code P1 Weave factor Vertical Wicking time in seconds (5cm Height) Weft Direction A A A A A A A A Figures 9.2 and 9.3 show the dependency of wickability on the integrated firmness factor and P1weave factor, when the ends/cm and picks/cm are kept constant. This can be described by the second order equation with a rather high coefficient of determination, which shows a regression equation correspondence to experimental values (R 2 =.752) for (Integrated weave factor) and (R 2 =.7) for P1 weave factor respectively. This shows that the fabric wickabilty varies with the P1 and factor for the eight types of weaves as stated in the previous chapters. The regression analysis results of the P1 weave factor and Integrated on wicking in weft direction are given in Table A.4.1 and A.4.2 respectively. (Appendix 4)

6 Integrated weave factor Figure 9.2 Effect of on Fabric wicking (weft direction-weft density 23.6/cm) y = x R² = P1 Weave factor Figure 9.3 Effect of P1 on Fabric wicking (weft direction-weft density 23.6/cm)

7 Effect of weft density on wicking Table 9.3 show the weft way vertical wicking results for 24 fabrics with three series of integrated firmness factors namely =.5, =. and =.. The was kept constant for all the eight weaves and the corresponding picks/cm S 2 were calculated. Table 9.3 Values of P1, calculated weft density and wicking time when is constant with different weaves Fabric Code P1 Weave factor =.5 S 2 Wicking(t),s 5cm (H) Weft Direction =. S 2 Wicking(t),s 5cm (H) Weft Direction =. S 2 Wicking(t), s 5cm (H) Regression Weft R 2 Direction A A A A A A A A The extent to which wickability shows a change among different weaves is found to be less in this case. As the values of fabric integrated firmness factor decreases, wickability increases which is due to the openness of fabrics. Figures (9.4 to 9.11) present fabric wickability dependences of individual weaves of weft density S 2 (in this case, too, warp density S 1 =23. 6picks/cm, however, = const). From these curves, it is apparant that when weft density increases, fabric wickability decreases. As the picks/cm increases the rate of wicking decreases for all the eight types of weaves which is shown in Figures 9.4 to Values of R 2

8 99 were found to be higher which demonstrates a very good correlation between weft density and wickability. 7 y = x R² = Figure 9.4 Effect of picks/cm on wicking Fabric Code (A1) 7 y = 3.827x R² = Figure 9.5 Effect of picks/cm on wicking Fabric Code (A6)

9 1 7 y = 2.125x R² = Figure 9.6 Effect of picks/cm on wicking Fabric Code (A4) 1 y = 2.491x R² = Figure 9.7 Effect of picks/cm on wicking Fabric Code (A5)

10 y = 1.9x R² = Figure 9.8 Effect of picks/cm on wicking Fabric Code (A3) y = 1.918x R² = Figure 9.9 Effect of picks/cm on wicking Fabric Code (A1)

11 12 1 y = 1.481x R² = Figure 9.1 Effect of picks/cm on wicking Fabric Code (A7) 7 y = 1.87x R² = Figure 9.11 Effect of picks/cm on wicking Fabric Code (A8)

12 Effect of P1 Weave Factor on Wicking when is Constant As stated earlier in this chapter the dependencies of wickability by integrated weave factor were depicted by R 2 which are.7 and.75 respectively. The dependencies of pick density on wickability ranges from R 2 =.957 to.999. Hence, it is clear that the pick density, P1 weave factor and ( ) fabric integrated factor strongly influence the fabric wickability. Tables 9.4, 9.5 and 9.6 show the weft way vertical wicking results for eight different weave factor P1, made of Polyester/Viscose. The fabrics were manufactured in three series i.e. series 1, series 2 and series 3 with the same firmness factor ( =.5, =. and =.). Figures 9.12 shows that when the factor =.5 the dependence of the weave factor P1 on fabric wickability was found to be poor (R 2 =.6). The regression analysis results of the P1 weave factor and wicking for weft direction when =.5, are given in Table A.4.3 (Appendix 4) When the factor is. and., the dependencies of these on fabric wickability are poor (R 2 =.2 and R 2 =.5). (Figures 9.13 and 9.14).The regression analysis results of the P1 weave factor and wicking for weft direction when =. and. are given in Tables A.4.4 and A.4.5 respectively. (Appendix 4) This study clearly showed the variability in wicking results of eight different weaves when the fabric integrated firmness factor was kept constant. So we may state that fabric wickability does not depend on the fabric weave factor P1, when the integrated firmness factor is constant. Although wickability of fabrics strongly depends on both thread density and weave factor, their combined effect by keeping firmness factor

13 14 constant on S 2 and P1 is found to be very marginal. It follows that it is possible to design a fabric of suitable wickability according to the fabric firmness factor. The sole effect of P1 weave factor on wickability has been studied by keeping fabric integrated firmness factor constant. The effect of P1 weave factor was singled out by this process. Table 9.4 Values of P1 and Wicking results when =.5 Fabric Code P1 Weave factor =.5 Vertical Wicking time in seconds (5cm Height) Weft Direction A A A A A A A A y =.75x R² = P1 Weave factor Figure 9.12 Effect of P1 on wicking ( =.5)

14 15 Table 9.5 Values of P1 and Wicking results when =. Fabric P1 Weave Vertical Wicking time in seconds Code factor =. (5cm Height) Weft Direction A A A A A A A A y = -.322x R² = P1 Weave factor Figure 9.13 Effect of P1 on wicking ( =.)

15 16 Table 9.6 Values of P1 and Wicking results when =. Fabric P1 Weave Vertical Wicking time in seconds Code factor =. (5cm Height) Weft Direction A A A A A A A A y = -1.3x R² = P1 Weave factor Figure 9.14 Effect of P1 on wicking ( =.)

16 CONCLUSION An investigation of the effect of various weaves namely plain weave; warp rib; twill 2/2; weft direction Bedford cord; fancy twill ; sateen; basket weave ;crape weave; of polyester/viscose 19.5 tex, 2ply yarns on fabric wickability was carried out. It has been found by experiments that, although fabric wickability depends on the weft density and weave factor P1, by maintaining constant and varying weft density, identical wickability for different weaves can be achieved. The influence of pick density and fabric weave factor PI at a constant fabric firmness factor on wickability is very poor. It means that it is possible to design a fabric with good wickability based on fabric firmness factor.