Coir is a material which is widely used to overcome the problem of erosion. When woven into geotextiles and placed on areas in need of erosion control it promotes new vegetation by absorbing water and preventing top soil from drying out. Coir geotextiles have a natural ability to retain moisture and protect from the suns radiation just like natural soil, and unlike geo-synthetic materials, it provides good soil support for up to three years, allowing natural vegetation to become established.
Traditionally the coconuts were left to cure in water for several months (or in brine for a longer period for white fibres) then the coir was extracted. However with technology there is an increased use of coconut husk defibering machines.
Typically, white coir spun into yarn is used in the manufacture of rope and, thanks to its strong resistance to salt water, in fishing nets. Brown coir is stronger and more widely used than white coir. Applications include sacking, brushes, doormats, rugs, mattresses, insulation panels and packaging.
Coir fibres measure up to 35 cm in length with a diameter of 12-25 microns. A coconut harvest occurs once in 45 days. From 1000 coconuts it would be possible to extract 10 kgs of coir. Among vegetable fibres, coir has one of the highest concentrations of lignin, making it stronger but less flexible than cotton and unsuitable for dyeing. The tensile strength of coir is low compared to abaca, but it has good resistance to microbial action and salt water damage and needs no chemical treatment.
There are two types of coir: the more commonly used brown fibre, which is obtained from mature coconuts, and finer white fibre, which is extracted from immature green coconuts after soaking for up to 10 months. Mature coir fibres contain more lignin, a complex woody chemical, and less cellulose than fibres such as flax or cotton.