Ultra-fine circular-knit fabrics are as much of a trend as ever. Which yarns are best suited to them?
The Groz-Beckert Online Newsletter already reported in its second 2010 edition on the properties and potential applications of ultra-fine knitted fabrics, all the way to sewing that meets precise requirements. Now we'll take a look at how to choose the right yarn for the job.
In principle, filament yarns in gauge dtex 22 to 50 are an economically efficient alternative to production on circular knitting machines with high gauges. Spun yarns made from cotton and cotton mixes are often required by the market because of their special textile properties. The picture above shows very clearly the yarn numbers (Ne) required for spun yarns, in relation to the knitting machine gauge range (E). It is clear that for ultra-fine machine gauges of E50 to E66, spun yarns of Ne 90 to Ne 150 are required.
The spinning of ultra-fine yarns like these requires very fine, extra-long-staple cotton fibres with an average fibre length of approx. 1 ¾" (44.5 mm). With a single-fibre linear density of 1.22 dtex, and with yarn number Ne 150, just 33 fibres are theoretically available in the yarn cross-section. Such long-staple types of cotton come for example from Peru (Pima) or Egypt (Giza). The right raw material is not enough in itself, however, because it is only by making full use of the complete fibre length that the highest-gauge cotton yarns can be produced. The shorter proportion of fibre is removed by combs. Three methods of final spinning can still be considered: the classic ring spin method, the compact spin method and the air spin method, also known as the "air jet spin method."
If you need to know more about optimal yarn selection, our experts at Groz-Beckert will be happy to assist you.