Coir Fiber: Properties, Production Process and Advantages

coir fibers

What is Coir Fiber?

Coir fiber, often called coir, comes from the fibrous husk inside a coconut. To produce coir, the husks are soaked until the textile fibers can be separated. Although the production process takes time, coir has many uses. Coir is unique among natural fibers because it’s not cultivated solely for coir extraction. In contrast, jute fiber and sisal fiber are primarily grown to produce fibers that are later spun and woven into various products. Other fibers like jute, sisal, cotton, and similar ones come from plants with shorter cropping cycles, while coir fiber is derived from the nearly perennial coconut palm.

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History of Coir Fiber

Coconut palm trees have been cultivated for over 4,000 years, making them one of the world’s oldest plant species. In around 60 A.D., a Greek sailor documented an East African community in what is now Tanzania. They were crafting boat planks by weaving coconut fibers. By the 11th century, people in Sri Lanka and India had acquired the knowledge of extracting and processing coconut fibers, thanks to teachings from Arab traders.

Types of Coir Fiber

There are two main coir fiber types:

  1. Brown coir fiber
  2. White coir fiber:
  • Brown coir fiber: The process begins by soaking the fibrous husks in water to make them soft. Then, a method called wet-milling is used to separate long bristle-like fibers from shorter mattress fibers under the nut’s surface. These mattress fibers are carefully cleaned and dried to make bales. Some are kept a bit moist for flexibility. Coir fiber can be twisted without breaking and holds a wavy shape. Twisting is done by hand or with a machine to make ropes. Longer bristle fibers are cleaned in water, dried, and bundled. They can be straightened with steel combs. Coir bristle fibers can be bleached and dyed to get different colors. It has a tough, coarse texture and a high lignin content, giving it durability and resistance to decay. Brown coir fiber is primarily used for making doormats, floor mats, brushes, and ropes.
  • White coir fiber: Green husks are hung in water for around ten months. Microorganisms work to break down the plant material around the fibers during this time, making them easier to get. Afterward, the husk sections are beaten by hand to separate the long fibers, which are then dried and cleaned. Once clean, the fibers are ready to be spun into yarn using a simple one-handed method or a traditional spinning wheel. White coir fiber is used for crafting finer brushes, twine, and cushion filling.

Chemical Composition

  • Cellulose: 71.07%
  • Hemicelluloses: 8.50%
  • Lignin: 29.23%
  • Pectin: 14.25%
  • Water: 26%

Properties of Coir

  • Coir fiber from coconut shells is relatively short, usually 15-35 centimeters in length, with a diameter of 12-25 microns.
  • Coir fiber taken from tough coconut husks, is incredibly durable and tough. It’s waterproof, resistant to saltwater damage, and tough against microbes.
  • Coir fiber is great for insulation against temperature and sound. It’s also naturally resistant to bugs and mold, so it doesn’t rot.
  • Coir fiber doesn’t wrinkle easily; it’s quite resilient.
  • Moisture doesn’t affect the coir fiber, and it remains unchanged.
  • Cleaning coir fabric is easy, making it simple to maintain.
  • Coir’s downsides include being unstable in size, flammable, unsuitable for high heat, and sensitive to UV light, acids, and bases.

Processing of Coir Fiber

Coconut plants grow well along the coast and produce coconuts throughout the year. Green coconuts, typically harvested after about a year of growth, have soft white fibers. On the other hand, brown fiber comes from fully mature coconuts, which are picked when the edible part around the seed is ready for making copra and desiccated coconut.
To process coconuts, they are first de-husked by driving them onto a spike to split the fibrous layer from the tough shell. The fibrous husks are then soaked in water in pits or nets, which makes the fibers swell and soften. ‘Wet-milling’ is used to separate the longer bristle fibers from the shorter mattress fibers underneath the nut’s skin. The mattress fibers are cleaned of impurities, dried, and compacted into bales. Some of the mattress fibers are intentionally kept slightly moist to preserve their elasticity for making “twisted” fibers.
Coir fiber is flexible and doesn’t break when twisted. It maintains a curled appearance, much like it’s permanently waved. Twisting is done by creating a rope from the hank of fiber, either by hand or with a machine. Longer bristle fibers are cleaned in clean water, dried, and bundled. They can also be straightened and rid of shorter pieces through a process known as “hackling” using steel combs.
Coir bristle fiber can be bleached and dyed in various colors for buyers. To extract the white fibers, young husks are soaked in water for up to ten months, allowing microorganisms to break down the plant tissues around the fibers, a process called retting. Then, segments of the husk are manually beaten to separate the long fibers, which are later dried and cleaned. The cleaned fibers are ready for home-based yarn spinning, using either a simple one-handed system or a spinning wheel. Before they are sold and shipped, a final grading step is taken.

Advantages

  • Coir¬†fiber is exceptionally tough and can regain its original shape even after heavy use. It’s highly resilient, unaffected by moisture, and easy to clean.
  • It’s also fire-resistant, making it highly unlikely to catch fire. Its durability also extends to its resistance to fungi and moths, reducing the risk of decay.
  • Coir fiber is eco-friendly because it comes from the same plant that gives us coconut water and meat. It’s completely biodegradable, and even its leftovers can be used as fertilizer.

Uses For Coir

  • Construction
  • Household Items
  • Furniture
  • Ropes
  • Netting
  • Landscaping
  • Gardening
Coir Fiber: Properties, Production Process and Advantages
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