Fibres are the raw material from which textiles are made for clothing ,household,floor covering and industrial uses . For convenience fibres are generally classified  as being either natural or manmade ,that is formed by chemical processes ,usually involving extrusion of the fibre .

            In 1971 the  ‘free ‘ world  production  of  natural fibres was estimated at  17,832,000 tons , while manmade  fibres  was  8, 415,000 tons . Natural fibre production ,however was stable or increased only slightly in the years 1950- 1971 , while manmade production expanded steadily ,with a fourfold increase in the period . When manmade fibres have relied on petrochemical  expansion which is currently in question ,natural fibre production expansion is difficult owing to high production costs and competition for  land  utilization .

           The use of natural fibres goes back to the Stone Age  when flax and hemp were  exploited . Eventually  wool ,silk and cotton fibres were discovered and were known to have been in use for several thousand years BC . In mediaeval times wool processing was a major occupation ,but industrial processing ,involving mainly wool and cotton dates from about 1750 .

           In modern times ,all three natural kingdoms ,animal ,vegetable and mineral ,supply textile fibres . Natural  fibres are the essential  alternative  in the ever  expanding  horizon of textile fibres . Natural  fibres are becoming   the essential  necessity  and are available  abundantly . They are  non-toxic  in nature  besides ; the disposal   of fibre wastes  is easier as they are necessarily biodegradable . Bast  fibre and  leaf  fibre  are already in use in plenty in the textile industry. But till date  no much work is done on seed and fruit fibres like Coir/Coconut , Tree Cotton,   Java Kapok , Balsa fibre , Milkweeds , etc.

           Coconut is the main crop cultivated  in Lakshadweep . It is India ‘s largest producer of coconuts . About 2,598  hectares are under coconut cultivation and the productivity per hectare is 22,310 . Coir fibre producer are based in Tamil Nadu . They export to China, Taiwan , Malaysia. The biggest exporter is Sunco Exporters Pvt Ltd , Pollachi ,Tamil Nadu . Segregation  of coir fibre is done in Allepy ,Kerala.

        Total world coir fibre production is 250,000 tonnes . 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 throughput 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 .

  As per the Coir Board  ,India has a bilateral trade agreement dating back to 1956 with Chile .

Production and Processing –  

             Coir  is a coarse  fibre which comes from the husks  of coconuts . In other words coir is Cocos nucifera and is obtained  from the husk surrounding the nut ,that is the  fruit  of the coconut plant . 

             The husks are quartered  and put in large water tanks and weighted with a network of iron rails . After five days the husks are  removed  and  run through a machine  composed of two corrugated iron rollers that crushes them and prepares them for the next machine , called the  drum . The husks are held against the revolving drums and the spikes tear out the woody part , leaving the long ,coarse fibres separated . The fibres are   then made  into hanks .

           Coconuts are the seed of the palm trees . These palms flower on a monthly basis and the fruit takes 1 year to ripen. A typical palm tree has fruit  in every stage of maturity .A mature tree can produce 50 – 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 do up to 2,000 coconuts per hour .

            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 shifted 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.

            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 spinning wheel.  

The coir fibre can be dyed using reactive dyes,vat dyes and sulphur dyes. It can be bleached using hydrogen peroxide. When dyed black , coir fibre looks very much like horse hair.

Structure  and  Properties –

             It is Coarse . Dark brown colour . Individual fibres short ; 0.5 mm ( 1/50 th  inch ) long . Thick  walled  with  irregular lumen . Surface covered with pores . Coir fibres are found between the husk and the outer  shell  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 . There  are two varieties of  coir

             1. Brown Coir – It 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.They are  made up of small threads ,each about 1mm long and 10 to 20 micrometers in diameter .

            2. White  coir –  The fibres are harvested from the coconuts before they are ripe . These fibres are white or light brown in colour 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.

    In the form in which it is taken from the coconut husk , coir fibre is composed of a number of reddish-brown ,strong,elastic filaments of different lengths, which are thickest in the middle of their length and taper towards the ends : in cross-section  they are round or elliptical . The diameter in the middle varies from 0.002 to 0.012 inches. These filaments , however , are each made up of a number of irregularly –thickened  ultimate fibre cells which vary in length from about 0.4 to 1 mm and have a diameter of 5 to 8 microns .

     Fibre Properties

Type of fibre Tensile  strength ( MPa) Elongation  ( % ) Toughness (MN/m2)
Sisal 580 4.3 1250
Pineapple 640 2.4 970
Banana 540 3.0 816
Coir 140 25.0 3200

Uses  –

             Coir  fibres and yarns  are used  for making coarse cloths and  bristles for brushes. It is used for cordages ,matting, brushes . Coir  is also used  geo textiles   . It provides a low impact and affordable solution  to the problems  of soil erosion and land sliding . It  has been laid along the land  adjoining the Konkan Railway track . For  natural geo –textiles , coir is still preferred  to jute , as it possesses  strength , durability and high content of lignin . Moreover , for   geotextiles ,  it is  not necessary  to have a similar shade of coir yarn. It is used for brush-making ,door mats , fish nets , cordage .

                     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 togother ) are shaped and cut to fill mattresses and  for use in erosion control on river banks and hill sides . A major proportion of brown coir pads are sprayed with rubber latex which bonds the fibres togother ( rubberized 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 recommended as substitute for sphagnum moss because it is free of bacteria and fungal spores , and is sustainably produced without the environmental damage caused by pelt mining . 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.

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

     India is promoting through Coir Board   various products like Coir geo textiles  and Coir Ply  besides products like floor mats and coverings. India exports to Chile  coir products worth 375.43 tonnes valued at Rs 2.54 crores in 2007.

   Indian spinning mills should try  to add coconut fibre in dyed or grey form along with other  cellulosic or synthetic fibre  in  different  proportion  and make  fancy yarns . It can be tried as a replacement for  costly flax and ramie fibres.