The impact of cotton fibre properties on textile

Where micronaire alone is measured, its importance lies in the fact that it affects processing waste (lower micronaire fibres break more easily during mechanical action), neps (lower micronaire fibres are generally more flexible and entangle more easily to form neps), short fibre content, spinning performance, yarn and fabric quality, dyed fabric appearance and neppiness in particular. Lower micronaire cottons also tend to become more easily entangled around particles of trash and leaf, thereby increasing the amount of good fibre removed. These features affect processing performance, and product quality and costs. Lower micronaire cottons also need to be carded slower. Neps can interfere with drafting, resulting in end-breakages during spinning. If micronaire levels within a lay-down or mix vary unduly (by more than 0.2 units), it could lead to streakiness or barré because of differences in dye shade. It is generally considered that both too-low and too-high micronaire cottons should be avoided, the ideal range being between about 3.8 and 4.2 for American Upland type cotton. Nevertheless, micronaire values below 3.8 would be preferable provided the cotton is mature, particularly for rotor spinning.

Maturity, which is largely determined by growing conditions, can be defined as the relative wall thickness (i.e. the area of the cell wall to that of a circle with the same perimeter as the fibre, or the ratio of the cell wall thickness to the overall ‘diameter’ of the fibre).