Never say Dye: Use naturally colored cotton
June 29th, 2015 | Waleed Ahmad, Naveed Mushtaq and Basit Ahmad Khan | No Comments
ON ONE hand, waves of objection have been raised for Bt Cotton in Pakistan and other parts of the world whereas on the other hand, one of its ancient time cousins is making a silent come back. It is the naturally colored cotton which is gifted with natural colors. Colored cotton is not a product of any modern biotechnology or genetic engineering. In fact, it has a history of more than 5000 years. Natural colored cotton is a naturally pigmented fiber. Numerous lint colors i.e. black, brown, red, mahogany red, khaki, blue, pink, dirty white, green and, obviously, white are found in the four species of the genus Gossypium. Its cultivation dates back to nearby 2700 B.C in Egypt, Peru and Indo-Pakistan.
In contrast to white cotton, naturally color fibers were coarse, weak and short. They were utilized only for hand spinning. Though, with the dawn of ginning machines and power looms after the industrial uprising, the scenario changed radically. White cotton, with its long, strong and soft fibers could easily be adjusted to mechanization. Furthermore, when chemists were able to produce economically a variety of artificial colors and learnt the skills of staining cotton fiber, naturally colored cotton gently faded into the background. It is stated that in the Second World War, because of the scarcity of artificial dyes led to the cultivation of brown and green cotton in the Soviet Union in huge quantities to produce soldiers outfits. The US government also exhibited concern in cultivation of naturally colored cotton however later abandoned the project due to low yield and short fiber length.
Courtesy to the environmental awareness of current society, the wheel of fortune appears to have come a full round for colored cotton. Unlike naturally colored cotton, white cotton has to be bleached and processed before dying. Many of the treating chemicals and dyes utilized in cotton industry are identified to cause health perils. Bleaching agents, chlorinated products formaldehydes, phenols, which are engaged for processing and bleaching, cause skin diseases. Dyes comprising traces of heavy elements such as lead, arsenic, cobalt, cadmium, chromium, zinc, are also skin irritants. Children are specifically sensitive to these effects. The azodyes are recognized carcinogens. Dying and processing are also water intensive. Ejections from cotton mills contaminate water resources and affect people and marine life. Therefore, numerous of these chemicals have been banned in several countries. Germany bans even import of fabric stained with azodyes. Hence, people are shifting to the environment-friendly colored cotton. Though, colored cottons are inherently mediocre to white cotton in one or more features. Agronomically, some have fewer boll weight and boll number. Economically some are low in lint index and yield. Hence, plant breeders are trying to produce superior varieties by crossing strains with needed qualities to make colored cotton more machine friendly and attractive.
The first commercial achievement came in 1988 when Sally Fox of Natural Cotton Colors, USA succeeded, after eight years of breeding struggles, in producing machine-spinnable colored cotton. Her cotton – orange, grey, yellow, and even mauve are woven into jackets, shirts, socks and sheets by some major garment manufacturers. Though, blue, the color of the versatile jeans, has appealed cotton breeders. Now biotechnology has stepped in. Two companies, Calgene in North California and Argacetus in Wisconsin plan to insert the genes which are responsible for the production of blue color in the indigo plant into white cotton. They believe to produce, machine-friendly blue cotton. Geneticists have been studying the complex inheritance pattern of color in cotton.
Naturally colored cottons are exclusive, because they diminish the use of artificial dyes. They are popular with environmentally conscious users and those who are sensitive to the dyes in regular cotton. Naturally, colored cottons have a remarkably soft texture and the color does not fade but deepens with washing, naturally colored cotton is environmentally friendly as well as inexpensive. Eradication of coloring in production could save from $.60-1.50 per pound of cloth. Naturally colored cotton is also resilient to change as compared with the conventional dyed white cotton. After laundering, the color becomes sturdier and stronger, a characteristic recognized during research studies at Texas Tech University.
Some naturally colored cotton deepens with exposure to the sun. Though, green is less firm and fades to tan when exposed to sunshine. Cotton growers use almost 23% of the worlds insect repellent and 10% of the worlds pesticides to fight pests. These compounds not only harm the labors who use them but also seep into the soil, reaching rivers, streams and ground water, killing fish and polluting livestock. Naturally, colored cottons on the other hand, resist pests, drought and salt better, so they lessen toxic pesticide use thus causing less environmental pollution and are very adaptable to organic farming and dry land. There is experimental proof to show that naturally pigmented cottons, especially green cotton, provide shield from UV radiation for the embryonic cotton seeds, though they can also offer protection from the suns injurious rays for users who wear outfits manufactured from these naturally colored fibers. These cotton varieties also eradicate the bleaching and coloring costs and an extreme energy usage. Besides being low yielder, colored fiber fetches premium price for its cultivators than white cotton.
The movement for naturally colored cotton has just started. It has a long way to go. There are 15,000 Peruvian farmers who are involved in the cultivation of organic cotton, of which colored cotton is a part. It is also cultivated in smallholdings in USA, China, Russia, and Israel. A few companies, for example Levi, Patagonia, Strauss and Esprit have shown interest to produce garments from colored cotton fibers, mainly childrens outfits and fancy fabrics. Due to smaller fiber, it becomes impractical to use naturally pigmented cotton for clothing manufacturers. But now, colored cotton is literally squeezed in with the conventional white cotton to make its fiber stronger and longer than other naturally pigmented cotton to be used in usual looms. Since this hybrid cotton fiber is stronger, it is being used by Levis, L.L. Bean, Eileen Fisher, Fieldcrest and khakis.
In Pakistan, research work has been started at Cotton Research Institute (SRI), Sakrand in Sindh, Central Cotton Research Institute (CCRI), Multan in Punjab and some other research stations and results are promising. The natural colored cotton is getting popular due to firmness of color, disease resistance, and better fiber characteristics. Recognizing the importance of natural colored cotton, CRI Sakrand has started transferring fiber color genes from exotic ones into local high yielding and early maturing varieties.
If the commercial cultivation of colored cotton becomes fruitful in Pakistan, it can open doors for new vistas. Already there has been an effort to produce dyed yarn cones in Pakistan to produce fabrics with different stripes and patterns. Production of colored cotton means no bleaching, processing and dying. Pakistan can gain significantly from production of colored cotton for a number of reasons. These comprise exports of clothing and textile to developed countries, limited processing facilities and poor capacity utilization in the spinning division. In future, some of the local manufacturers can focus on this specific market proposing higher profit margin.
Published in: Volume 06 Issue 26
Short Link: http://www.technologytimes.pk/?p=13687