Coir coconut fiber is a natural cellulose fiber which is obtained from coconut husk. It is the fibrous material that is found between the outer coat of a coconut and the hard internal shell. Copra is the dried coconut kernels from which coconut oil is obtained. Coir coconut fiber comes from a natural and renewable source and is one of the latest eco-friendly alternatives for textiles. Coconut farming usually focuses on coconut oil, milk and water and other coconut products like desiccated coconut with the coconut husk being discarded as waste.
By using coconut husk, which is a bi-product of coconut farming, a waste product can be converted into eco-friendly and sustainable products.
Coconut palm trees grow in many coastal tropical areas of Central America, Asia, Oceania and Africa and has been cultivated for more than four thousand years. The three top producers are Indonesia, Philippines and India and together they account for around 89 percent of world production.
Coconut palms flower monthly and each fruit takes a year to ripen. Harvesting is done on an ongoing basis with each tree annually yielding 50 to 100 fruits.
Coconuts are primarily a food crop but also provide fiber, fuel and building material. The coconuts that we generally see and buy, are the seeds of the fruit of the coconut palm tree.
There is an external leathery skin and a thick (5 to 8 cm) intermediate layer of fibrous pulp that surrounds the seed. The fiber that is obtained from the pulp is called coir. Depending on the thickness of the husks, each coconut or copra yields 80 to 150 grams of husk fibers.
Coir Coconut Fiber Production
Coir coconut fiber is obtained from the husks through conventional retting or mechanical and biological means. Retting is the action of micro-organisms and moisture to dissolve or rot cellulose tissues and pectin away from bast-fiber bundles.
- Conventional process: to soften the fibers, the husks are retted in brackish water for three to six months or in saltwater for ten to twelve months. During retting micro-organisms break down the plant tissues around the fibers to loosen them. The fibers are separated through decortication and beating and then hackled and washed. These produce the best quality fibers.
- A mechanical process has been developed to decorticate or defribillate the husks but the quality is not as good as conventional retting. Through the mechanical process retting can be shortened or even eliminated. Ripe husks can be processed in a crushing or shredding machine after only seven to ten days of retting. Immature husks can be dry milled without retting but produces only short fibers.
- A biological means of retting through enzymatic processes have also been developed, whereby enzymes are used to separate the fibers. The process is cleaner and milder than the mechanical process and can be done without any water pollution. It produces a better quality fiber than through mechanical processes.
Traditionally the retted pulp is beaten with a wooden mullet to separate the fibers from the pith and outer shell. In recent years the fibers are separated either by hand or in a rotating drum that has spikes on the inside.
Coir coconut fibers are either white or brown, depending on the age or maturation of coconuts on harvesting.
- White fibers come from immature or green coconuts which are harvested after six to twelve months on the plant. These fibers are weaker than brown fibers, but smoother and finer. White fibers can be spun into yarn which can be woven into mats or twisted into rope or twine. Green coconuts are retted in seawater or artificially salinated water.
- Brown fibers are obtained from fully ripened and mature coconuts. The coconuts are harvested when the nutritious layer around the seed is ready to be processed into copra and desiccated coconut. It produces coarse but strong fibers and the fibers have a high abrasion resistance. Ripe coconuts are retted in fresh water.
Fibers from both brown and white coir range in length from ten to thirty centimeters. Long fibers that are at least twenty centimeters long, are called bristle fiber and the shorter fibers are called mattress fiber. About a third of the coir coconut fiber that each coconut will yield, is bristle fiber. Shorter fibers have a finer texture and is normally spun into yarn.
Coir pith is the residue that is left behind after the fibers have been extracted.
Eco-friendly innovations with Coir Coconut Fiber
1. Coir Textiles
“Cocona” fabric is a textile that has been created from recycled coconut shells. Activated carbon is taken from the coconut shells and added to fibers, yarns and fabrics. The result is clothing that dries quickly, stays cool, absorbs odors and provides UV protection. It makes Cocona fabric ideal for sports wear.
By replacing synthetic polyester fibers with coconut husk fibers, consumption of petroleum will be reduced by two to four million barrels per year and carbon emissions by 450,000 tons per annum.
2. Coir Building Boards
A method has been developed in the Philippines to use the fibrous husk of coconuts to produce high quality building boards called “Ecocoboards”. Eco-friendly technology is used and no chemical adhesives are added. Panels and boards can be used for building and furniture applications and can be substituted for wood.
The Philippines has a shortage of wood so the use of Ecocoboards will reduce the amount of wood that has to be imported. The commercial use of coconut husks would increase the profitability of coconut farming and contribute to the export and economy of the Philippines.
Benefits of Coir Coconut Fiber:
- Coir coconut fiber is eco-friendly and bio-degradable. It comes from a renewable source and the fibers or fabrics are 100% bio-degradable.
- It is hard wearing and durable. Coir coconut fiber is water resistant and is the only fiber that is resistant to saltwater damage.
- Coconut husk fibers have a quick drying time. It absorbs moisture 50% faster than polyester.
- It eliminates odors – coir coconut fiber naturally absorbs odors and can minimize bad smells without additional treatments and chemicals.
- Coir coconut fibers absorbs harmful ultraviolet rays even after several washes, so provides UV protection.
- It is very strong.
Disadvantages of Coir Coconut Fiber
There is concern about the amount of water that is used in retting and extracting coir coconut fiber from the husks. Traditional retting generates water pollution with many organic pollutants left behind in the water. These include pectin, tannin, fat, pectosan, toxic polyphenols and several types of bacteria including salmonella.
Scientists are experimenting with treatment options to reduce the amount of water pollution, with some manufacturers claiming that they are treating the effluent water. Biological retting is a cleaner process and doesn’t pollute the water.
Uses of Coir Coconut Fiber:
There are many versatile uses for coir in products like brushes, mattresses, upholstery padding, doormats and floor mats, rope, sacks, insulation, tiles, fishing nets and many more.
Coir coconut fiber makes perfect nets for harvesting shellfish and ropes for marine applications as it will not be damaged by seawater.
Coir is used in horticulture as a soil less growing medium and is an alternative to peat moss and vermiculite. It is used in hydroponics and make perfect linings for hanging baskets. Coir bricks or chips will add drainage and absorbency to potting soil and will absorb up to ten times it’s weight in water.
Coconut biomass has the potential to be used to generate energy. A new coconut power plant in Thailand has been designed specifically for the combustion of all forms of coconut waste and also conventional biomass.
As technology improves and production increases, new uses for coir coconut fiber are found and promoted. Coir is becoming a popular choice for making geotextiles. Geotextiles are permeable fabrics which when used in conjunction with soil, have the ability to filter, separate, protect, reinforce or drain. As more people turn away from non-biodegradable synthetics, use of natural fibers and geotextiles will increase.
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