Effect of Blend Ratio on Quality Characteristics of Polyester/Cotton Blended Ring Spun Yarn

Cotton is a cool, soft, comfortable and is the principal clothing fiber of the world. Cloths made of this fiber absorb and release perspiration quickly, thus allowing the cloth to “breath.” The advantages of polyester over cotton fibers are its strength, brightness, easy-care, low price, consistency in quality and availability. But it has low moisture regain (0.4%) as compared to cotton (8%). There is no perfect fiber that contains all the qualities of cotton and polyester mentioned above. In this context, blending is the technique to combine fibers which emphasizes the good qualities and minimizes poor qualities of the fibers. In blends of polyester/cotton, the fibers provide crease recovery, dimensional stability, tensile strength, abrasion resistance, moisture absorption, drape ability, etc. Different blend ratios of P/C have been considered for experiment, i.e., 100% cotton, CVC (60% cotton, 40% polyester) and PC (50% cotton and 50% polyester). In this work, we studied the yarn characteristics with several P/C blend ratios of 30/s Ne. Here, the properties of blended ring spun yarns are compared with the same of 100% cotton yarn and the results are discussed in terms of the following quality parameters: Mass irregularity (CV% and U%), Thick, Thin & Naps (IPI: Imperfection Index), CSP, single yarn strength and Hairiness.


Introduction
Blending of various fibers is extensively practiced for uplifting the performance and the aesthetic properties of cloth. Blended of natural fibers with man-made ones can provide the benefits of combining the good properties of both fiber components, such as comfort, softness, strength etc. These advantages also allow an increased variety of products to be made and deliver a stronger marketing advantage [1]. Reckoning of the performance of blended yarns has also been studied by numerous authors [2][3][4][5]. Natural fibers and their blends with man-made fibers improve the performance characteristics. They may be used for clothing, underwear, socks, hygienic, textile products as well as for composites [6]. Blending in the cotton spinning process has the aim to make yarn with suitable quality and cost. Use of adequate machines and techniques to select bales and knowledge of its characteristics is necessary to produce a good quality blend [7]. Years back, it had been a common practice to carry out the blending of natural and synthetic fiber in sliver form on the draw frame. The best blend in longitudinal direction was obtained in this way [8]. Department of Textile Engineering, Bangladesh. Li & Yen [9] investigated that, fiber properties have a significant effect on yarn strength. However, Nawaz [10] concluded that the gradual decrease in yarn strength occurs as the share of polyester fibers in the blend decreases. Anandjiwal & Goswami [11] suggested that blending dissimilar fibers lead to their non-uniform distribution throughout the yarn cross section, which in turn, lead to preferential migration depending on both fiber properties and mechanism of spinning process adopted. Therefore, the present study was carried out to figure out the effect of polyester/cotton blend ratio on quality characteristics of resultant yarn.
the purpose of experiencing the quality of polyester-cotton blended yarn the following cotton and polyester samples are consider, which are shown in Table 3-5 in details. After having the cotton and polyester with mentioned mixing ratio, the resultant yarn was observed for testing the performance depending on the blending ratio. Uster® evenness tester 4 was used to have the quality parameters and performance of the polyester-cotton blended yarn. Here, three types of blend ratio were considered for yarn count of 30s', i.e., KW (100% Cotton), CVC (60% cotton + 40% polyester) and PC (50% cotton + 50% polyester). The comparison of quality parameters of these three blends was subjected in this study, which is given in Table 6 & 7.         Figure 1 shows the relationship between the yarn blend ratio and U% & CV% for various blend ratios of cotton and polyester. It is clearly revealed in the graph that U% & CV% decrease gradually with the increase in polyester proportion. We hereby infer that increase in polyester share in blend results in lower U% and CV% and that the increase proportion of polyester brings down yarn U% and CV% to an appreciable extent.

Effect of polyester/cotton blend ratio on thick +50%/ km
A relationship between the blend ratio and number of thin places in the yarn for the various blend ratios was found. It is observed that the number of thin places in the yarn decreases with the increase in the polyester proportion in the blend, which is shown in Figure 2.  Figure 3: Effect of polyester/cotton blend ratio on thin-50%/km.

Effect of polyester/cotton blend ratio on thin -50%/km
From Figure 3, it is observed that there is a relation between the blend ratio and number of thin places in the yarn for the various blend ratios. It is also observed that the number of thin places in  Figure 5 shows the relation between the blend ratio and the IPI in the yarn. IPI graph also shows an inverse nature with the increase in polyester share in the blend. So, an increase in polyester share in the blend has much lower IPI (Imperfections). Figure 6: Effect of polyester/cotton blend ratio on CSP. Figure 6 explains the strength values of the various blend ratio yarns. The graph reveals that increase in polyester proportion increases the yarn strength, which infers that an increase in polyester share in the blend has much higher CSP. A relation between blend ratio and hairiness index of the various blended yarns is stated in Figure 7. The nature of the graph shows that, an increase in polyester share in the blend decreases the hairiness of the yarn.  Figure 8 determines the tenacity values of the blended yarns. The graph shows that the tenacity value increases with the increase in polyester proportion. We hereby infer that increase in polyester share in the blend has much higher strength. The elongation of the yarn for the various blend proportions is stated in Figure 9. The graph reveals that, there is an increase in extension with an increase in the polyester share in blend.

Conclusion
The study was carried out to figure out the effect of polyester/ cotton blend ratio on quality characteristics of resultant yarn. The study reveals that, with the increase in polyester share in the blend, the overall quality parameters of yarns are improved. Some of them are U%/CV%, IPI, Hairiness, CSP and single yarn strength. At the same time, moisture regain% of the yarns decreases with the increase in polyester share in the blend; Such as, for 100% cotton: MR is 8.4%, for 40/60 PC: MR is 5.7% and for 50/50 PC: MR is 5.0%. However, depending on the end uses, the optimum percentage of polyester and cotton may be adjusted.