History
The uses of cotton have been known in Asia for around 4,000 years (Egypt). Cotton reached Europe via Spain in the 13th century AD, and arrived in Germany for the first time in the 14th century. Large financial and, as a result, social revolutions, took place. The processing of cotton experienced an upswing through the invention of the spinning machine in 1768 and the mechanical loom in 1787.
Growth Conditions
Cotton is a bushy plant between 0.7 and 1.7m in height. It thrives best in sandy, limy soil and in a warm, humid climate (subtropical). Buds can be seen two months after sowing. These buds produce white, yellow or red flowers, developing into three to five walnut-sized capsules with three to eight kernels. The usable cotton threads are located in the kernels.
Harvest
Harvest takes place over the course of 80 to 100 days, spread among three to five culling periods. Harvesting is done either by hand or by machine. Harvest amount and thread quality completely depend on weather conditions.
Thread Extraction
The cotton threads are forcibly separated from the kernels with gins (gutting machines). On average, 100kg of raw cotton yields 70 kg of kernels and 30 kg of threads. After gutting, short threads still hanging on the kernels are extracted by special gins. They come to the market as linters and are the raw material for the manufacturing of acetate, etc.
Main crop growing countries
China
USA
Central Asia (ex-USSR)
India
Pakistan
Brazil
Turkey
Egypt
Australia
Greece
Together these countries product about 3/4 of the world's cotton harvest.
Three international standards were created for the description of the various cotton types. These are:
USA cotton
Indian cotton
Egyptian cotton
Cotton from all other countries is assigned to one of these 3 groups.
Types
There are more than 10 known types attainable through crossbreeding. The following categories have been established:
- Cotton with a long staple, higher staple length, a higher degree of fineness and a satin sheen. Example: Sea Island (USA)
- Cotton with a uniform staple. Example: Uplands (USA)
- Cotton with a short staple, rough and minor. Example: East Indian
Trading Types
1. USA / Sea Island (Georgia) is the most valuable. Uplands cotton is the smoothest and makes up the majority of cotton traded.
2. Egypt I / Mako is yellowish. Types include Sakellaridis and Ashmouny, as well as the white, rigid Karnak.
3. East Indian / Oomra, Bengal, Tinnevelly, Broach (short-stapled, minor, rough and impure).
4. South-American I / Good mid-quality type, coming from e.g. Pernambuco in Brazil, as well as from Peru, Mexico, Puerto Rico and Santo Domingo.
5. Mid-Asian / Very versatile. Short and medium-stapled.
6. European I / e.g. from Motril (Spain) and lzmir (Turkey).
Thread Characteristics I –Properties
Thread length is between 10 and 55 mm.
From 36 mm long-stapled cotton
20 to 35 mm medium-stapled cotton
Up to 20 mm short-stapled cotton
Below 10 mm linters
The thread profile during growth is circular, and reniform when mature. During maturation, the cell sap degenerates and the threads contract. Microscopic images of the thread axis show a wound, corkscrew-type cuff.
The thread consists of:
approx. 90% cellulose
approx. 7% water
approx. 3 % wax, fur, protein, ash
In its natural state, cotton is mostly gray-white, yellow, brown, red or somewhere in between. The fineness of the threads ranges from 12 to 18 microns (1 micron = 1/1000 mm). The longest threads are nearly always the finest threads. Sheen increases with fineness and the spirals of the cotton threads. Durability is high and increases even further in a wet state.
Cotton is the natural fiber with the highest resistance to abrasion and also has a high level of wear performance. Cotton is boil-proof and very absorbent. This allows it to absorb large amounts of sweat while still remaining dry. In its wet state, cotton is vulnerable to light, causing it to yellow. Cotton can be ironed at relatively high temperatures (180 to 200 degrees Celsius).
Properties of Cotton:
Heat-resistant, boil-proof, soft, pliant, fine, absorbent, resistant to electrostatic charge, permeable to air, hygienic, comfortable on the skin, doesn’t scratch, can absorb body moisture well, doesn’t make noise, doesn't stick on the skin or textiles, and doesn’t degrade under heat buildup. In addition, bacteria are killed by heat during washing and ironing.
Mako-Cotton
Mako cotton is a superb grade of cotton. It is very clear, capillary and soft. Because of its immense length it is very good to use as yarn. The defining characteristic of Mako cotton is its breaking strength.
Pima-Cotton
Pima cotton is distinguishable from other cotton types by its hair length and thickness. Pima cotton is handpicked. The best varieties of Pima cotton are distinguished by their degree and extra-long fibers. The cotton is soft, fine and glossy, which is why it is referred to as the “silk of South America.”