Scouring of blended fibre fabrics

The wide range of natural and man-made fibres provides many combinations to create new effects with desirable properties. Strength, wearibility and crease recovery are the main properties responsible for synthetic fibres becoming established for blends with cotton, viscose and wool. The acrylics are also in much demand for such blends, while polyamide fibres and triacetates are of secondary importance. 

Scouring is mainly designed to remove the natural oils and waxes from the cotton portion and the finish oils which manufacturer add to polyester fibres when extruded. Blends of polyester/cotton can be scoured with alkaline scouring agents as per conditions shown in Table 4.16. Trisodium phosphate can also be used as an TABLE 4.16 

Alkaline Scouring Conditions for Polyester/Cotton Blends 

Polyester/wool blends are very popular, the most common blend ratios are 55 45 and 70 30 polyester wool. Polyester rich blends are normally constructed from a texturised polyester fibre warp and 55 45 polyester wool weft yams. The 20 80 polyester/wool is woven from 55 45 warp and a pure weft yam. Worsted polyester/wool blend yams may contain 2.5 - 3% solvent extractable oil, compared with 3.5- 5% for similar all wool yams. The oils have much greater affinity for polyester fibre than wool and after normal piece scouring, the blends contain residual oil content of 0.6 - 1.2% compared with 0.3% for wool. Oxidation of combing oil is influenced by exposure to light which should be avoided before scouring. Addition of surfactant to combing oil improves the scourability of the blend fabric [75]. 

The object of scouring polyester/wool blended fabric is not only to remove spin finishes, lubricating oils, sizes and contamination of all types, it also helps in fabric relaxation and parting the necessary compactness. Blended fabrics may also be pressed and flattened by any of the usual methods employed with all-wool cloth before scouring. 

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