Fiber Impurity | Different Types of Impurities in Cotton


Ramandeep Singh
B.Tech, Dept. of Textile Engineering
Giani Zail Singh Punjab Technical University Campus,
Bathinda, Punjab, India

The term impurity is used to described material other than fiber which is found in raw or processed stock. Generally, impurities must be removed during the spinning process, so the type and amount of impurity is also of importance to the yarn manufacturer.

Impurities are also found in man-made fibers but the levels are much lower than those found in the natural fibers.

There are two types of impurities in cotton, they are
  1. Impurities in raw cotton
  2. Impurities in processed cotton
Now discussed overall impurities in cotton. 
Impurities in Raw Cotton:
The types of impurity found in raw cotton can be classified as follows :

Seed :
The largest type of impurity found in raw cotton. It may consist of un ginned seeds, with fibers still attached , ginned seeds or under-developed seeds and part of seed.
Seed in raw cotton
Chaff :
A collection of vegetable fragments, most of them consisting of leaf, bract, and stalk. Bract is a form of small leaf growing beneath the cotton boll.

Dirt :
Sand and soil which originates from the cotton field.

Dirt and Micro dust :
The finest of impurities consisting of very fine particles of chaff, dirt, small fiber fragments and mildew spores.

Trash :
The term trash is often applied to the combination of all the above impurities.
Trash in raw cotton
Impurities in Processed Cotton:
The types of impurity found in processed cotton can be described as follows :

The main impurities in processed cotton are Neps, Seed-Coat Fragments, and Non-Seed Impurities in Cotton. The production of high-quality fiber and textiles that meet the highest standards of the cotton industry has been a central and ongoing challenge in cotton research. Neps and white specks are imperfections that severely decrease textile quality at the consumer level and, therefore, have immense economic consequences. Neps are entanglements or clumps of immature fibers that produce imperfections when woven into fabric. Frequently, neps take up dye poorly and appear as light spots or white specks scattered randomly throughout dyed fabrics Seed-coat fragments are pieces of seed or mote (underdeveloped or aborted ovules) coats with fibers (mostly immature) attached that were broken or crushed during cotton processing. Motes are the main source of immature fibers, fiber clusters, and/or seed-coat fragments.
Neps in cotton
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Mazharul Islam Kiron is a textile consultant and researcher on online business promotion. He is working with one European textile machinery company as a country agent. He is also a contributor of Wikipedia.

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