FACTS AND GENERAL INFORMATION ON COTTON
Cotton is a vegetable fiber obtained from the mature capsule of the cotton plant, a shrub about 40cm high, with leaves and flowers of a red and yellow colour. When the flower is fecundated it loses its petals and within 25 days a capsule surrounded by a leaf called bract grows.
The capsule is sustained by a cup and has a drop shape rounded at the lower extremity. Inside the capsule there are from five to eight seeds on which the fibre developed. When the capsule is mature it opens into four parts showing the cotton ball.
On the same plant the maturation of the capsules does not occur simultaneously, therefore more passages are required for the harvest of the cotton. The harvest is carried out a week after maturation. The first operation after harvesting is husking, which permits the removal of the fibres from the seeds. Then the cotton is carded and combed so as to eliminate all the impurities.
4000 fibers is the seed average. Staple length for manufacturing yarns = 1/8" - 2.5" (0.32 - 6.35cm), for fabrics = 7/8" - 11/4" (2.22 - 3.18) is standard.
The requisites on the basis of which to judge the quality of the cotton are the grade, the colour and the length of the fibers as well as the character.
The grade us given by the external apperance of the cotton and is determind on the basis
- of the major or minor brightness of the fibers
- by its more or less white colour
- by the major or minor presence of particles of the leaf or other extraneous substances
The colour is another imporant element of evaluation of cotton. In fact, the major or minor whiteness of the cotton is crucial for the facility of later workings and the possibility of obtaining good yarns.
The length is the most important attribute of the fiber. In this regard, cotton is divided into three categories: long fiber cottons (long staple) with measures more than 28mm and short fiber cotton (short staple) that do not reach a length of 18mm. Long staple cotton originates usually from the USA, whereas the shorter come from Asian regions. The intermediary categroy, cotton fibers between 18mm-28mm, constitute the grand mass of the world production of around 60%.
The character is the attribute determined with more difficulty. It is partly conntected with the cotton's origin, variety and maturity. But at the end, cotton of good character is that whose fibers are the strongest and most robust. Those properties lead to traction and breakage resistance as well as uniformity so that they are easy to work with.