By: Patricia Bel-Berger and Grant Roberts
Introduction to Neps
What is a cotton nep - what do they look like?
A nep can be defined as a small knot (or cluster) ofentangled fibres consisting either entirely of fibres (i.e. a fibre nep) or offoreign matter (e.g. a seed-coat fragment) entangled with fibres. In contrastto the loose arrangement of a worsted nep, a cotton nep generally has a tightformation.
In most cases, fibrous neps are found to contain at leastfive fibres, with the average number being 16 or more. (van der Sluijs, 1999).The structure of a raw cotton lint nep has been described by British StandardsInstitute as well-defined and as containing a core structure of relativelydense entangled fibres. This core typically ranges from 0.3 to 3 mm indiameter and may contain a piece of trash or seed; pieces of seed withoutattached fibres are not neps (Verschraege, 1989). From this core, an array offibres extends 5 to 10mm, sometimes even up to 25 mm, in length. 1
Due to the apparent differences of formation, there aredifferent classifications for neps. Neps have been grouped in three ways: seedcoat with entangled fibres; trash with entangled fibres, and solely entanglefibres without contaminating particles, which primarily consist of immatureor dead fibres. In addition, neps are defined in two distinctions as eithermechanical or biological.
Biological neps are neps that contain foreign material,whether the material is seed coat fragments, leaf, or stem material (Figure1) (Hebert, 1988). In unginned cotton, biological neps are typicallyassociated with motes (malformed seed, unfertilized ovules, and dead seed),while in ginned cotton (i.e. cotton lint); they typically contain seed-coatfragments (SCF).
Mechanical neps are those that contain only fibres and havetheir origin in the manipulation of the fibres during processing (Figure2)1.
The last type is a shiny nep or white speck nep, found onthe surface of dyed fabrics, they appear as light or white spots and are seenonly in the finished fabric (Figures 3 and 4) 4.
Comments