Results & Discussion

The 20/1 Ne (30-tex) rotor-spun yarn produced for size-free weaving evaluation had excellent metrics. For example, it had single-strand mean breaking strength of about 500 cN, count-strength product equal to 128 kN/tex, and Uster unevenness CV index of 12.8% with very low numbers of imperfections (viz., the thick and thin places and neps) at classical sensitivity levels. Incidentally, the above metrics of a rotor-spun yarn were better than those of a run-of-the-mill, ring-spun carded cotton yarn of equivalent-size. A ring-spun yarn typically is about 20% stronger than an equivalent and comparable open-end spun yarn. At any rate, the yarn performed very well with no yarn failure during warping and beaming operations.

Regarding the warp preparation for (loom) beaming, the research has shown that a continuous washing of warp sheet (under nominal tension) in boiling water (containing a wetting agent and possibly a small amount of rice soap), followed by drying (on steam-heated cylinders) can adequately relax the yarn and, hence, set/control its twist liveliness. It has also been observed that the referenced wash & dry treatment slightly increases (by ~ 15%) the yarns tensile strength, presumably due to the yarns expected shrinkage in boiling water. At any rate, the beaming process did not present an anticipated problem relating to the yarn twist torque or liveliness, which ensured that the (size-less) beaming process adopted was satisfactory. However, it may also be mentioned that, instead of the adopted, costly yarn washing and drying treatment on a dummy slasher, any other relatively less-expensive method or technique of setting the yarn twist torque (say, by using a HW Yarn Conditioner or a pressure cooker) could be deployed in conjunction with either 1) an ordinary beaming operation on a dummy slasher without heating its cylinders or 2) a modern sectional-warping process (i.e., without using a dummy slasher) to efficiently prepare a loom beam from a size-less warp. The representative scheme for beaming towards the present study is shown in Figure 2.

1)    First Treatment: No application of any fluid &/or heat.

2)    The yarn was sitting on the cylinders, while the latter were being heated from room temperature to 220⁰ F.

3)    Second Treatment: cylinders at 220⁰ F.

4)    The yarn was sitting on the cylinders at 220⁰ F, while the water for yarn washing was being boiled in the (size) box.

5)    Third Treatment: The yarn was washed in the boiling water and dried on the cylinders at 220⁰ F.

6)    Fourth Treatment: Conventional sizing

7)    The yarn was sitting on the heated cylinders, while the preparation for conventional sizing (control) was being made.

8)    Fourth Treatment: The warp was slashed with the traditional size.