Coir

Coir

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Encyclopedia
Coir ˈ is a natural fibre extracted from the husk
Husk
Husk in botany is the outer shell or coating of a seed. It often refers to the leafy outer covering of an ear of maize as it grows on the plant. Literally, a husk or hull includes the protective outer covering of a seed, fruit or vegetable...

 of coconut
Coconut
The coconut palm, Cocos nucifera, is a member of the family Arecaceae . It is the only accepted species in the genus Cocos. The term coconut can refer to the entire coconut palm, the seed, or the fruit, which is not a botanical nut. The spelling cocoanut is an old-fashioned form of the word...

 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
Coconut
The coconut palm, Cocos nucifera, is a member of the family Arecaceae . It is the only accepted species in the genus Cocos. The term coconut can refer to the entire coconut palm, the seed, or the fruit, which is not a botanical nut. The spelling cocoanut is an old-fashioned form of the word...

. 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.

Etymology


The English word Coir had its origin from the malayalam
Malayalam language
Malayalam , is one of the four major Dravidian languages of southern India. It is one of the 22 scheduled languages of India with official language status in the state of Kerala and the union territories of Lakshadweep and Pondicherry. It is spoken by 35.9 million people...

 word and Tamil
Tamil language
Tamil is a Dravidian language spoken predominantly by Tamil people of the Indian subcontinent. It has official status in the Indian state of Tamil Nadu and in the Indian union territory of Pondicherry. Tamil is also an official language of Sri Lanka and Singapore...

 word .

Structure


Coir fibres are found between the hard, internal shell and the outer coat of a coconut
Coconut
The coconut palm, Cocos nucifera, is a member of the family Arecaceae . It is the only accepted species in the genus Cocos. The term coconut can refer to the entire coconut palm, the seed, or the fruit, which is not a botanical nut. The spelling cocoanut is an old-fashioned form of the word...

. The individual fibre cells are narrow and hollow, with thick walls made of cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....

. They are pale when immature but later become hardened and yellowed as a layer of lignin
Lignin
Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants and some algae. The term was introduced in 1819 by de Candolle and is derived from the Latin word lignum, meaning wood...

 is deposited on their walls. Each cell is about 1 millimetre (0.0393700787401575 in) long and 10 micrometre in diameter. Fibres are typically 10 to 30 cm (3.9 to 11.8 ) long. 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
Flax
Flax is a member of the genus Linum in the family Linaceae. It is native to the region extending from the eastern Mediterranean to India and was probably first domesticated in the Fertile Crescent...

 and cotton
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....

 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.

Processing


Coconuts are the seed of a species of palm
Arecaceae
Arecaceae or Palmae , are a family of flowering plants, the only family in the monocot order Arecales. There are roughly 202 currently known genera with around 2600 species, most of which are restricted to tropical, subtropical, and warm temperate climates...

, Cocos nucifera
Coconut
The coconut palm, Cocos nucifera, is a member of the family Arecaceae . It is the only accepted species in the genus Cocos. The term coconut can refer to the entire coconut palm, the seed, or the fruit, which is not a botanical nut. The spelling cocoanut is an old-fashioned form of the word...

. 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
Copra
Copra is the dried meat, or kernel, of the coconut. Coconut oil extracted from it has made copra an important agricultural commodity for many coconut-producing countries. It also yields coconut cake which is mainly used as feed for livestock.-Production:...

 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
Retting
Retting is a process employing the action of micro-organisms and moisture on plants to dissolve or rot away much of the cellular tissues and pectins surrounding bast-fibre bundles, and so facilitating separation of the fibre from the stem...

. 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.

Uses



Brown coir is used in floor mats and doormats
Mat
A mat is a generic term for a piece of fabric or flat material, generally placed on a floor or other flat surface, and serving a range of purposes including:* providing a regular or flat surface, such as a mousepad....

, brush
Brush
A brush is a tool with bristles, wire or other filaments, used for cleaning, grooming hair, make up, painting, surface finishing and for many other purposes. It is one of the most basic and versatile tools known to mankind, and the average household may contain several dozen varieties...

es, mattress
Mattress
A mattress is a manufactured product to sleep or lie on, consisting of resilient materials and covered with an outer fabric or ticking. In the developed world it is typically part of a bed set and is placed upon a foundation....

es, floor tiles and sacking. A small amount is also made into twine
Twine
Twine is a light string or strong thread composed of two or more smaller strands or yarns twisted together. More generally, the term can be applied to any thin cord....

. 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
Latex
Latex is the stable dispersion of polymer microparticles in an aqueous medium. Latexes may be natural or synthetic.Latex as found in nature is a milky fluid found in 10% of all flowering plants . It is a complex emulsion consisting of proteins, alkaloids, starches, sugars, oils, tannins, resins,...

 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
Thermal insulation
Thermal insulation is the reduction of the effects of the various processes of heat transfer between objects in thermal contact or in range of radiative influence. Heat transfer is the transfer of thermal energy between objects of differing temperature...

 and packaging.

The major use of white coir is in rope
Rope
A rope is a length of fibres, twisted or braided together to improve strength for pulling and connecting. It has tensile strength but is too flexible to provide compressive strength...

 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
Horticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...

, coir is a strongly recommended substitute for sphagnum moss because it is free of bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 and fungal
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...

 spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

s, and produces good results without the environmental
Natural environment
The natural environment encompasses all living and non-living things occurring naturally on Earth or some region thereof. It is an environment that encompasses the interaction of all living species....

 damage caused by peat mining. Coir is also useful to deter snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

s 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
Aspergillus terreus
Aspergillus terreus is a fungus commonly used in industry to produce important organic acids, such as itaconic acid and cis-aconitic acid. It was also the initial source for the drug mevinolin , a drug for lowering serum cholesterol. A. terreus may cause opportunistic infection in people with...

 which acts as a biological control against plant pathogenic fungi.

Coir is an allergen
Allergen
An allergen is any substance that can cause an allergy. In technical terms, an allergen is a non-parasitic antigen capable of stimulating a type-I hypersensitivity reaction in atopic individuals....

, 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.

Major producers


Total world coir fibre production is 250000 tonnes (246,050.9 LT). The coir fibre industry is particularly important in some areas of the developing world. India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

, mainly the coastal region of Kerala
Kerala
or Keralam is an Indian state located on the Malabar coast of south-west India. It was created on 1 November 1956 by the States Reorganisation Act by combining various Malayalam speaking regions....

 State, produces 60% of the total world supply of white coir fibre. Sri Lanka
Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...

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, pith is now being used as mulch, soil treatment and a hydroponic growth medium.

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