Bamboo textile

A scarf made of bamboo yarn and synthetic ribbon

Bamboo textiles are cloth, yarn, and clothing made out of bamboo fibres. While historically used only for structural elements, such as bustles and the ribs of corsets, in recent years a range of technologies have been developed allowing bamboo fibre to be used in a wide range of textile and fashion applications. Modern clothing labeled bamboo is usually rayon. The bamboo yarn can also be blended with other textile fibres such as hemp or even spandex.

Traditional uses

Kinhyōshi yōrin (Yang Lin), hero of the Suikoden, holding a bamboo hat, from Utagawa Kuniyoshi's series of woodblock prints illustrating the 108 Suikoden

In China and Japan, thin strips of bamboo were woven together into hats and shoes. One particular design of bamboo hats was associated with rural life, being worn almost universally by farmers and fishermen in order to protect their heads from the sun.

An 1881 bustle design

In the West, bamboo, alongside other components such as whalebone and steel wire, was sometimes used as a structural component in corsets, bustles and other types of structural elements used in fashionable women's dresses.

Modern uses

Manufacture of bamboo viscose

See also: Rayon: Production method

Cellulose from bamboo is suitable for processing into viscose rayon. Bamboo leaves and the soft, inner pith from the hard bamboo trunk are extracted using a steaming process and then mechanically crushed.

Viscose manufactured from bamboo is promoted as having environmental advantages over wood-pulp viscose. Bamboo crops may be grown on marginal land unsuitable for forestry; although demand for bamboo has sometimes led to felling of forests to plant bamboo, though this has become less common since Chinese forestry policy reforms in the 1990s. The viscose processing results in the same chemical waste products as wood-pulp viscose, notably carbon disulfide, but bamboo cellulose is suitable for a closed-loop viscose process that captures all solvents used.

Alternative manufacturing processes

The Swiss company Litrax is one company involved in the manufacturing of bamboo fibre. Litrax claims to use a more natural way of processing the bamboo into fibre. In this the woody part of the bamboo is crushed mechanically before a natural enzyme retting and washing process is used to break down the walls and extract the bamboo fibre. This bast fibre is then spun into yarn. In fine counts the yarn has a silky touch. The same manufacturing process is used to produce linen fabric from flax or hemp. Bamboo fabric made from this process is sometimes called bamboo linen. The natural processing of litrax bamboo allows the fibre to remain strong to produce an extremely high quality product. This process gives a material that is very durable.

Some bamboo fibre is made by a bacterial process similar to retting flax into linen fibre.

Another means of extracting fibre from bamboo is practiced in the days preceding the annual festival of the Kottiyur temple of Kerala, India. The handcrafted bamboo artefact is in the form of a tuft of white fibres of up to a foot in length. The article is made out of newly emerging bamboo culms which go through a process of alternating pounding with stones and retting in water, followed by a combing to remove the pith, leaving the fibres and a stub of the bamboo.

Source of raw material

Most of the bamboo used to make bamboo fibre and bamboo clothing is grown in China by Hebei Jigao Chemical Fiber Company, which holds several patents on processes for turning bamboo into fibre. To strictly control the quality of raw material, Hebei Jigao Chemical Fiber Company has built its own bamboo plantation in Sichuan Province, China, and keeps strict control over it. The proof of the ecologically sound methods behind bamboo production is the fact that all of the fibre produced at the facility in China is Oeko-Tex 100 certified. This certifies that the finished fibre has been tested for any chemicals that may be harmful to a person’s health and has been found to contain no trace chemicals that pose any health threat whatsoever. This means that every company working with bamboo starts with the same raw material and that this material is not contaminated.

Bamboo fibre

Bamboo fibre is a cellulose fibre extracted or fabricated from natural bamboo, and possibly other additives, and is made from (or in the case of material fabrication, is) the pulp of bamboo plants. It is usually not made from the fibres of the plant, but is a synthetic viscose made from bamboo cellulose. (In the US, the Federal Trade Commission (FTC) has ruled that unless a yarn is made directly with bamboo fibre — often called “mechanically processed bamboo” — it must be called "rayon" or "rayon made from bamboo". However, the EPA noted that although the manufacturing process further purifies the cellulose, alters the physical form of the fibre, and modifies the molecular orientation within the fibre and its degree of polymerization, the product is essentially the same chemical as the raw material.

Manufacturers tout the fact that bamboo can be cultivated quickly, can be used as a cash crop to develop impoverished regions of the third world, and is a natural fibre (as opposed to popular synthetics like polyester) whose cultivation results in a decrease in greenhouse gases. Around 75% of all polluting emissions coming from the bamboo viscose process occur in the form of air emissions.

There may be environmental problems with the cultivation of land expressly for bamboo plantations, and the use of harsh chemicals to turn bamboo into usable fibre for clothing.

Bamboo is very resilient and durable as a fibre. In studies comparing it to cotton and polyester, it is found to have a high breaking tenacity, better moisture-wicking properties, and better moisture absorption.

Bamboo composite and biopolymer construction

There are various approaches to the use of bamboo in composites and as an additive in biopolymers for construction. In this case, as opposed to bamboo fabrics for clothing, bamboo fibres are extracted through mechanical needling and scraping or through a steam explosion process where bamboo is injected with steam and placed under pressure and then exposed to the atmosphere where small explosions within the bamboo due to steam release allows for the collection of bamboo fibre. Bamboo fibre can be in a pulped form in which the material is extremely fine and in a powdered state.

Ecological considerations

Growth

Bamboo has many advantages over cotton as a raw material for textiles. Reaching up to 35 metres (115 ft) tall, bamboo is the largest member of the grass family. They are the fastest growing woody plants in the world. One Japanese species has been recorded as growing over 1 metre (3.3 ft) a day. There are over 1600 species found in diverse climates from cold mountains to hot tropical regions. About 40 million hectares of the earth is covered with bamboo, mostly in Asia. The high growth rate of bamboo and the fact that bamboo can grow in diverse climates makes the bamboo plant a sustainable and versatile resource.

The bamboo species used for clothing is called Moso bamboo. Moso bamboo is the most important bamboo in China, where it covers about 3 million hectares (about 2% of the total Chinese forest area). It is the main species for bamboo timber and plays an important role for the ecological environment.

Harvesting

Once a new shoot emerges from the ground, the new cane will reach its full height in just eight to ten weeks. Each cane reaches maturity in three to five years. It is a grass and so regenerates after being cut just like a lawn without the need for replanting. This regular harvesting actually benefits the health of the plant—studies have shown that felling of canes leads to vigorous re-growth and an increase in the amount of biomass the next year.

Yield and land use

Land use is of global importance as the world’s seven billion people compete for water, food, fibre and shelter. Sustainable land use practices provide both economic and environmental advantages. Bamboo can be used as food, fibre and shelter and due to its ease of growth and extraordinary growth rate it is a cheap, sustainable and efficient crop. Bamboo grows very densely, its clumping nature enables a lot of it to be grown in a comparatively small area, easing pressure on land use. With average yields for bamboo of up to 60 tonnes per hectare greatly exceeding the average yield of 20 tonnes for most trees and the average yield of 2 tonnes per hectare for cotton, bamboo’s high yield per hectare becomes very significant.

Greenhouse gases

Growing forests absorb CO₂ but deforestation results in fewer trees to soak up rising levels of CO₂. Bamboo minimises CO₂ and generates up to 35% more oxygen than equivalent stands of trees. One hectare of bamboo sequesters 62 tonnes of carbon dioxide per year while one hectare of young forest only sequesters 15 tonnes of carbon dioxide per year.

Deforestation

Bamboo planting can slow deforestation, providing an alternative source of timber for the construction industry and cellulose fibre for the textile industry. It allows communities to turn away from the destruction of their native forests and to construct commercial bamboo plantations that can be selectively harvested annually without the destruction of the grove. Tree plantations have to be chopped down and terminated at harvest but bamboo keeps on growing. When a bamboo cane is cut down, it will produce another shoot and is ready for harvest again in as little as one year. Compare this to cotton – harvesting organic cotton requires the destruction of the entire crop causing bare soils to bake in the sun and release carbon dioxide into the atmosphere. Before replanting next year's crop the cotton farmers till the fields which releases yet more CO₂.

Water use

Very little bamboo is irrigated and there is sound evidence that the water-use efficiency of bamboo is twice that of trees. This makes bamboo more able to handle harsh weather conditions such as drought, flood and high temperatures. Compare bamboo to cotton which is a thirsty crop – it can take up to 20,000 litres of water to produce 1 kg of cotton and 73% of the global cotton harvest comes from irrigated land, Some estimates indicate that cotton is the largest user of water among all agricultural commodities.

Soil erosion

Yearly replanting of crops such as cotton leads to soil erosion. The extensive root system of bamboo and the fact that it is not uprooted during harvesting means bamboo actually helps preserve soil and prevent soil erosion. The bamboo plant's root system creates an effective watershed, stitching the soil together along fragile river banks, deforested areas and in places prone to mudslides. It also greatly reduces rain run-off. Conventional cotton-growing also causes a severe reduction in soil quality through the impact of constant use of pesticides on soil organisms.

Biodegradable

Just like other cellulose-based clothing materials, bamboo fibre is biodegradable in soil by micro organisms and sunlight. Having reached the end of its useful life, clothing made from bamboo can be composted and disposed of in an organic and environmentally friendly manner.

Pesticides and fertilizers

A huge benefit of using bamboo as the organic base for textile fibres is that there is no need for pesticides or fertilizers when growing bamboo. However, herbicide and fertilizer applications are common in some places to encourage edible shoot growth. Bamboo also contains a substance called bamboo-kun – an antimicrobial agent that gives the plant a natural resistance to pest and fungi infestation, though some pathogen problems do still exist in some bamboo plantations.

By contrast, only 2.4% of the world’s arable land is planted with cotton, yet cotton accounts for 24% of the world’s insecticide market and 11% of the sale of global pesticides. Many of these pesticides are hazardous and toxic.

An estimated 1 million to 5 million cases of pesticide poisoning occur every year, resulting in 20,000 reported deaths among agricultural workers and at least 1 million requiring hospitalisation. Even organic cotton farming uses pesticides – copper and copper salts.

Fertilisers are also applied to cotton fields to increase growth rate and crop yields.

Anti-bacterial claims of Bamboo Textiles

Even though bamboo fabrics are often advertised as antibacterial, finished bamboo fabric only retains some of bamboo's original antibacterial property. Some studies have shown rayon-bamboo to possess a certain degree of anti-bacterial properties. Studies in China (2010) and India (2012) have investigated the antibacterial nature of bamboo-rayon fabric against even harsh levels of bacteria such as Staphylococcus aureus and Escherichia coli. While the Indian study found that “bamboo rayon showed excellent and durable antibacterial activities against both gram-positive and gram-negative bacteria”, the Chinese study concluded "the bamboo pulp fabric just like cotton fabric has not possessed antimicrobial property".

The Federal Trade Commission (FTC) charges companies with fake antimicrobial claims when the fibre has been made with rayon. Critics cite the cotton industry's powerful lobbyist groups in influencing the FTC decision, and dismissal of the international studies proving otherwise.