Coir

Segregation of Coir fibre

Coir /ˈkɔɪr/ is a natural fibre extracted from the husk of coconut and used in products such as floor mats, doormats, brushes, mattresses etc. Technically coir is the fibrous material found between the hard, internal shell and the outer coat of a coconut. Other uses of brown coir (made from ripe coconut) are in upholstery padding, sacking and horticulture. White coir is harvested from unripe coconuts, and is used for making finer brushes, string, rope and fishing nets.

Contents

Etymology

The English word Coir had its origin from the malayalam word kayaru and Tamil word kayiru.[1]

Structure

Coir fibres are found between the hard, internal shell and the outer coat of a coconut. The individual fibre cells are narrow and hollow, with thick walls made of cellulose. They are pale when immature but later become hardened and yellowed as a layer of lignin is deposited on their walls. Each cell is about 1 millimetre (0.04 in) long and 10 to 20 micrometres (0.0004 to 0.0008 in) in diameter.[citation needed] Fibres are typically 10 to 30 centimetres (4 to 12 in) long.[2] There are two varieties of coir. Brown coir is harvested from fully ripened coconuts. It is thick, strong and has high abrasion resistance. It is typically used in mats, brushes and sacking. Mature brown coir fibres contain more lignin and less cellulose than fibres such as flax and cotton and so are stronger but less flexible. White coir fibres are harvested from the coconuts before they are ripe. These fibres are white or light brown in color and are smoother and finer, but also weaker. They are generally spun to make yarn that is used in mats or rope.

The coir fibre is relatively water-proof and is one of the few natural fibres resistant to damage by salt water. Fresh water is used to process brown coir, while sea water and fresh water are both used in the production of white coir.[2]

Processing

Coconuts are the seed of a species of palm, Cocos nucifera. These palms flower on a monthly basis and the fruit takes one year to ripen. A palm tree may have fruit in every stage of maturity. A mature tree can produce 50 to 100 coconuts per year. Coconuts can be harvested from the ground once they have ripened and fallen or they can be harvested while still on the tree. A human climber can harvest approximately 25 trees in a day, while a knife attached to a pole can up the number to 250 trees harvested in a day. Monkeys can also be trained to harvest the coconuts, but this practice is less efficient than other methods. Green coconuts, harvested after about six to twelve months on the plant, contain pliable white fibres. Brown fibre is obtained by harvesting fully mature coconuts when the nutritious layer surrounding the seed is ready to be processed into copra and desiccated coconut. The fibrous layer of the fruit is then separated from the hard shell (manually) by driving the fruit down onto a spike to split it (de-husking). A well seasoned husker can manually separate 2,000 coconuts per day. Machines are now available which crush the whole fruit to give the loose fibres. These machines can process up to 2,000 coconuts per hour.

Brown fibre

The fibrous husks are soaked in pits or in nets in a slow moving body of water to swell and soften the fibres. The long bristle fibres are separated from the shorter mattress fibres underneath the skin of the nut, a process known as wet-milling. The mattress fibres are sifted to remove dirt and other rubbish, dried in the sun and packed into bales. Some mattress fibre is allowed to retain more moisture so that it retains its elasticity for twisted fibre production. The coir fibre is elastic enough to twist without breaking and it holds a curl as though permanently waved. Twisting is done by simply making a rope of the hank of fibre and twisting it using a machine or by hand. The longer bristle fibre is washed in clean water and then dried before being tied into bundles or hunks. It may then be cleaned and 'hackled' by steel combs to straighten the fibres and remove any shorter fibre pieces. Coir bristle fibre can also be bleached and dyed to obtain hanks of different colours.

White fibre

The immature husks are suspended in a river or water-filled pit for up to ten months. During this time micro-organisms break down the plant tissues surrounding the fibres to loosen them — a process known as retting. Segments of the husk are then beaten by hand to separate out the long fibres which are subsequently dried and cleaned. Cleaned fibre is ready for spinning into yarn using a simple one-handed system or a spinning wheel.

Researchers at CSIR's National Institute for Interdisciplinary Science and Technology NIIST) in Thiruvananthapuram have developed a biological process for the extraction of coir fibre from coconut husk without polluting the environment. The technology uses enzymes to separate the fibres by converting plant compounds into soluble compounds and hence curbs the pollution of water-bodies caused by retting of coconut husks.[3]

Uses

Making coir rope in Kerala, India

Brown coir is used in floor mats and doormats, brushes, mattresses, floor tiles and sacking. A small amount is also made into twine. Pads of curled brown coir fibre, made by needle-felting (a machine technique that mats the fibres together) are shaped and cut to fill mattresses and for use in erosion control on river banks and hillsides. A major proportion of brown coir pads are sprayed with rubber latex which bonds the fibres together (rubberised coir) to be used as upholstery padding for the automobile industry in Europe. The material is also used for insulation and packaging.

The major use of white coir is in rope manufacture. Mats of woven coir fibre are made from the finer grades of bristle and white fibre using hand or mechanical looms. White coir also used to make fishing nets due to its strong resilience to salt water.

In horticulture, coir is a strongly recommended substitute for sphagnum moss because it is free of bacteria and fungal spores, and produces good results without the environmental damage caused by peat mining. Coir is also useful to deter snails from delicate plantings. Coir is also used as a growing media in intensive glasshouse horticulture.

Coconut coir from Mexico has been found to contain large numbers of colonies of the beneficial fungus Aspergillus terreus which acts as a biological control against plant pathogenic fungi.[4]

Coir is an allergen, as well as the latex and other materials used frequently in the treatment of coir. This should be noted specially for people with allergies using mattresses and other furniture made with coir.[5]

Major producers

Total world coir fibre production is 250,000 tonnes (250,000 long tons; 280,000 short tons). The coir fibre industry is particularly important in some areas of the developing world. India, mainly the coastal region of Kerala State, produces 60% of the total world supply of white coir fibre. Sri Lanka produces 36% of the total world brown fibre output. Over 50% of the coir fibre produced annually throughout the world is consumed in the countries of origin, mainly India. Together India and Sri Lanka produce 90% of the 250,000 metric tons of coir produced every year.

In the recent past, countries such as Mexico, Indonesia, Vietnam and certain Caribbean countries have started to supply to the global market in large scale. Decompressing the imported coir blocks have presented problems for many commercial growers. Many companies have installed machinery to bust the coir blocks apart in a dry state. Other companies have tried hydrating the coir blocks with water,however coir buster type machines are usually best. Coir buster type machines (US patent number 5,839,674) decompress the coir blocks apart by rubbing them apart in a chamber that keeps the coir blocks (or bricks) tightly compressed together crumbling the material,then sifting through a screen with no fiber damage.

Waste and by-products

Coir fibres make up about 1/3 of the coconut pulp. The other 2/3 is called the pith or dust, it is biodegradable but takes 20 years to decompose. Once considered as waste material,[6] pith is now being used as mulch, soil treatment and a hydroponic growth medium.[2]

See also

References

  1. ^ "Webster's Online Dictionary - Coir". http://www.websters-online-dictionary.org/definitions/coir?cx=partner-pub-0939450753529744%3Av0qd01-tdlq&cof=FORID%3A9&ie=UTF-8&q=coir&sa=Search#906. Retrieved 17 October 2011. 
  2. ^ a b c "Coir" from How Products Are Made
  3. ^ http://www.hindu.com/2009/04/30/stories/2009043054860500.htm
  4. ^ Hyder, Naveen; Sims, James J.; Wegulo, Stephen N.. In Vitro Suppression of Soilborne Plant Pathogens by Coir. Department of Plant Pathology, University of Nebraska, 448 Plant Science Hall, Lincoln, NE 68583. 2008-11-19. URL:http://www.agrococo.com/Pathogen_Suppression.pdf. Accessed: 2009-08-17. (Archived by WebCite at http://www.webcitation.org/5j5breEfV)
  5. ^ Nasobronchial Allergy and Pulmonary Function Abnormalities Among Coir Workers of Alappuzha URL:http://www.japi.org/july_2010/Article_03.pdf
  6. ^ Tom Woolley, Sam Kimmins, Paul Harrison, Rob Harrison. “Green Building Handbook Volume 1: A guide to building products and their impact on the environment”. Green Building Digest. Spon Press. 1997. ISBN 0-419-22690-7.

External links


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Look at other dictionaries:

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  • coir — ● coir nom masculin Synonyme de coco. ● coir (homonymes) nom masculin couard adjectif et nom masculin ● coir (synonymes) nom masculin Synonymes : coco coir n. m …   Encyclopédie Universelle

  • coir — s. m. Trimis de siveco, 10.08.2004. Sursa: Dicţionar ortografic  COIR s.m. 1. Plantă textilă exotică. 2. Fibră elastică extrasă din această plantă. [pron. coir. / < engl. coir]. Trimis de LauraGellner, 19.12.2004. Sursa: DN …   Dicționar Român

  • Coir — (koir), n. [Tamil kayiru.] 1. A material for cordage, matting, etc., consisting of the prepared fiber of the outer husk of the cocoanut. Homans. [1913 Webster] 2. Cordage or cables, made of this material. [1913 Webster] …   The Collaborative International Dictionary of English

  • Coir — (Coirshanf), der verarbeitete Bast der Cocosnuß, daraus gefertigt ist das Coirtanwerk, s. u. Cocosnüsse …   Pierer's Universal-Lexikon

  • Coïr — Coïr, soviel wie Kokosfaser, s. Cocos, S. 208 …   Meyers Großes Konversations-Lexikon

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  • Coïr — Coïr, die Fasern der Kokosnuß (s. Kokospalme) …   Kleines Konversations-Lexikon

  • coir — [kɔıə US kɔır] n [U] [Date: 1500 1600; : Tamil; Origin: kayivu rope ] the rough material that covers the shell of a ↑coconut, used for making ↑mats, ropes etc …   Dictionary of contemporary English

  • coir — [ kɔır ] noun uncount thick rough fibers from the shell of a COCONUT, used for making ropes and covering floors …   Usage of the words and phrases in modern English


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