Coconut Fibre - Coir
Coconut fibre, or coir as it is popularly known, is extracted from the husks of coconuts between the outer shiny skin and the hard shell.
The husk of the coconut is a valuable material. For centuries it has been found to have value in coconut producing countries. Either in its crude form to grow orchids or as mulch or in processed form as coir. Today, it can be made into products that are just as or even more valuable than coconut kernels. Only about 12% of all husks are used and so there are a vast majority that are either not used or used in a residual capacity.
At the very least, husks can be burnt as biomass to generate electricity and heat and this heat can be used to dry copra and/or purify water or other applications. This solution makes a lot of sense in the case of remote places such as the islands in the Pacific. Even burning husks is capable of doubling farmer incomes by creating value around husks. In remote places, electricity is often not available or very expensive if available. Returns on burning are justified by selling electricity to the local village.
Another option for using the entire husk is to shred or cube it for mulch. It was always well known that husks were good for orchid production and shredded or cubed husks enjoy growing demand. Japan imported small quantities in the late 1970s from the Philippines in very tidy cubes. Then Indonesia started to export shredded husks and now India too is offering neat cubes and shredded husks for export. Again, husks sold for mulch are given a commercial value that matches or can and should match prices paid for coconuts.
The third alternative is, of course, to produce fibre and peat. Returns depend very much on how far you go down the value chain. Peat is far more lucrative if you are packaging the final retail package and coir becomes the most profitable single coconut product as rubberised coir. Merely extracting fibre and peat is a commodity business and, as such, is very price dependent. It is viable only where husks can be collected or processed very cheaply.
-----------------------------------------------------------------------------------------------------burn as biomass
Roughly one-third the weight of a coconut is made up of husks, coir accounts for around 10% of the total weight. Husks from roughly 10 billion coconuts are used to extract coir fibre. There are major differences in the quality of husks depending on variety and the age of growth of a coconut. Some varieties yield longer fibres than others. Very little research has been done on the subject.
Basically, those from immature husks, say from coconuts used for desiccated production, that are known as green husks while those from fully mature coconuts are brown husks.There is a great deal of difference between the constitution of green and brown husks. It is not just a matter of colour or softness and cannot be disguised.
Green husks are retted for months in brackish water after which a fibre known as 'white fibre' is extracted by hand beating with tamarind sticks and spun and woven as nets, mats and matting, almost exclusively in India but some in Sri Lanka. The process is labour intensive, a bit unkind to the environment, and requires investment, which has persuaded producers to shorten the steps leading to a serious loss in quality.
Green Husks------------retting--------------manual extraction-------white fibre-------------bleaching and colouring----------------spinning-----------------weaving
Brown husks from mature coconutsdo not have to be retted, can be soaked or processed dry and the resulting fibre is known as 'brown fibre' which is used for rubberised coir, geotextiles, car seats, brushes and pads. Brown fibre comes as either a separated mattress and bristle fibres or as a mixed fibre. If seperated, bristle fibre can be spun and then weaved or used for brushes while mattress fibre mostly ends up as upholstery. Mixed fibre can be wtisted and then untwisted and rubberised. The leading producers of the latter are India, Sri Lanka, Thailand, Vietnam, Malaysia and the Philippines, although there is minor production in many other countries.
Over 85% of husks, or over 60 million tons are wasted or used for some residual purpose. In the 1980s there was an experimental plant for heat bonding of husks for timber by Zytek technologies, using German technology and machinery, just outside Manila led by a MIT post graduate by the name of Fin Rosa. This experiment has now been repeated with Common Fund for Commodities finance, is likely to go to the next stage aleady reached by Zytek 25 years ago, but is likely to come up with the obstacle that the previous full scale plant faced, namely, there is no established market demand for the resulting product. We do not expect the new work to lead to an advance, we opposed it when the request was being processed and consider the entire exercise to have been a waste of money.
The two most promising developments possible would appear to be greater use of coir and use of husks and shells for gassers as bio-fuel. Care must be taken to follow either option on coral islands since the biomass is very important to their survival.
There are no reliable published figures on global coir production, but we estimated it in 2015 as follows:
|PRODUCTION OF COIR FIBRE|
The above is our private assessment and we always welcome field comments as they will help us make our estimates more accurate. However, in the interim period coir production has been growing strongly, mainly due to strong demand from China.
'Brown fibre', as opposed to 'white fibre' is extracted from the husks of fully mature coconuts. It is unimportant whether the husks are taken from coconuts that have fallen to the ground or have been harvested from the palms. The variety of coconut is relevant since some have on average longer fibres than others. It is also important that the husks are not cut horizontally since this would cut the resulting fibres. Over 1.2 million tons of brown fibre are believed to be produced today, of which India produces 560,000 tons, or roughly half.
Current production levels show a marked increase in consumption over the years from the 120,000 ton levels in the 1960s. Production used to be the exclusive preserve of India and Sri Lanka with their low wage rates compared to other coconut producing countries.But the fundamentals have changed with wage rates in India climbing in relation to some other coconut producers, mechanisation of extraction and a change in production economics due to the growth of the market for peat.
New producers have thus entered the market and production is gaining pace in countries like Philippines and Indonesia as well as earlier movers like Vietnam, Thailand, Malaysia and Ghana.
Mature coconut husks are made up of:
Dust and pith 66.6%
Bristle, longer fibres 33.3%
Mattress and shorter fibres 66.6%
The traditional way in which brown coir was extracted was by means of the Sri Lanka Drum, where husks that had been thoroughly soaked were manually held against a revolving spiked drom which extracted the fibre. This method resulted in the best quality of brown fibres but was slow and often led to accidents for the workers. No mechanical means are quite as good but are far cheaper.
Therefore, the process was mechanised and there are two basic ways of doing it. One is to soak husks and then feed them into a defibring machine which basically does what the Sri Lanka Drum used to do but without the need for husks being held by hand in dangerous circumstances. This is known as the 'wet milling' or'defibring' process. It is good at extracting longer bristle fibres as well as shorter mattress fibres which can later be separated. Defibring does also result in some loss of dust and pith.
Sakthi, a ;eading supplier from India - Defibring set.
There is a dry process, known as 'decortication' although it is normal to spray husks with water and it entails bursting the husk and separating fibres from dust and pith. The dry process maximises recovery of dust and pith, which have become as valuable as the fibre but results in a mix of bristle and shorter fibres. Decortication has become the dominant method used today.
There are finer differences between different output of different machines and how they are operated. Crude machinery tends to tear some of the longer fibres and the resulting mix is thus weaker. A lot of people offer coir extraction machinery but what is saved on price may end up more than lost in the prices that resulting products secure. It is folly to think all coir extraction machinery on offer is roughly equally efficient and acceptable - they are not. Thinking that any machinery will do is crude and misplaced.
Even after choice of machinery has been made, it is important how it is used with speed leading often to inferior grades of fibre. The best extraction equipment used to be from Germany and Austria but some Indian manufacturers produce acceptable quality. For larger throughputs of good quality fibre, the German machinery is probably still superior. There is also some terrible machinery for sale which may produce accepted grades for the crudest possible purposes but leads to products that do not conform to world market standards that have evolved over centuries.
The extraction process results in fibre and dust and pith and when defibring is used in dust and pith and mattress and bristle fibres.
Once coir has been extracted, it can be baled either as decorticated or bristle and mattress separately and can be traded as such. The largest single importer today, China, has so far been importing baled mixed fibres. Bulk decorticated baled fibre is the cheapest coir that is traded. Very often, there is further processing before trading.
All coir can be and often is twisted into ropes. This imparts a permanent curl to the fibre which is useful to many customers. You can buy twisted decorticated, mattress or bristle or even twisted coir with various proportions of mattress or bristle.
But bristle fibre is often spun into a yarn using a cotton lead thread. The yarn be single or two or more ply according to need. Yarn is thus traded as such, generally for further processing but coir yarn is also used as such. Yarn can be woven to make matting, nets and handicrafts, while bristle fibre is also used for brushes and brooms and other similar applications.
Baled decorticated coir or mattress fibre is purchased to be used a stuffing or for further processing. It is a traditional material for upholstery filling. However, it can also be twisted into ropes or used in the production of geotextiles.
Coir is often made into pads:
Restoflex rubberised coir sheets in different thicknesses and new Robco DOA process line
The highest value paid for coir is as rubberised products. Twisted coir is the primary feed material, it is combined with rubber latex. The most common mix of the two is 50:50 but it can be varied according to the density required. When to be used for car seats, swine hair is often mixed with the coir.
Twisted coir ropes
Twisted coir is sprayed with latex foam and is hydraulically pressed into sheets for use as mattresses or pads amongst other products and in moulds as car seats and other moulded products. The resulting products are then vulcanised.
Rubberised coir products enjoy the advantage that they are usually premium or superior products and the leading consumers are now India, China and Europe. Mercedes Benz is the best customer in the world for rubberised coir car seats, followed by Volkswagen.
A fleece of coir can also be punched by needles to give the pad greater stability and strength. The most common use of needlefelt is to cover spring structures in upholstery and mattresses. Most inner spring mattress plants have a needlefelt plant to supply the pads.
Needled pads are one of the oldest and most established coir products and are used as geotextiles as well as over inner spring structures and insulation pads.
Alternatively a fleece of twisted coir can be stitched togather using a yarn made of pp, cotton or jute to impart stability and strength. the resulting products is popular as a geotextile.It is better to use natural fibres for the yarn as it makes the blanket fully biodegradable.
A relatively new application which owed much of its initial popularity to insulation as roof greening on Federal Buildings in Germany but is now a very widely used geotextile being produced in coir producing countries as well as USA.