Series on Fibres: Turning Hemp into Fabric

Charlie Bradley Ross Tuesday, 2 December 2014

Did you know the very first pair of Levis were made of hemp? And did you know that hemp was planted near and around the Chernobyl nuclear disaster site to pull radioactive elements from the ground?

Derived from the Cannabis Sativa plant, the fibres of hemp are well known for their durability and ruggedness. In their raw state, hemp fibres are yellowish grey to deep brown. Prior to Levis Strauss' ingenious use of hemp to create his first jean, hemp was largely used as an industrial fibre, but soon became popular in the textile world after it was used in this first pair of jeans.


Materials made from hemp have been discovered in tombs dating back to 8,000 B.C. Hemp was primarily used in making sails and ropes for ships. In fact, the ships on which Christopher Columbus sailed to America in the 1400s were rigged with hemp. It is now widely recognized as a sustainable fabric that is exceptionally strong. Hemp, thus finds various uses ranging from eco-fashion apparel to household décor.

Hemp is a fibre with numerous benefits. As a crop, it grows extremely fast and yields more fibre than cotton or flax. It is a robust plant that requires no toxic pesticides or fertilizers. Hemp, controls top soil erosion and even renders the soil fertile for subsequent crops.

Production of Hemp

Hemp quickly reaches maturity and the plants reach a height of two to four metres in 80 to 120 days. It can be densely packed into fields with up to 150 plants per square metre of soil. Since it is naturally pest resistant, it can be grown organically without the aid of chemicals.

The sequence of steps that are followed from the moment that hemp is ready for harvest:

  1. The plant is harvested during the early to mid-flowering stage. Running cutter bars 4 to 5 feet above ground harvest both the hemp fibre and seeds. After this, the stalk is cut and baled.
  2. The hemp fibres are separated by retting, which is the process of decaying pectin that binds the hemp fibres to the core of the stem. By retting, the long bast fibres are separated from the non-fibre parts of the stalks. This is done either using chemicals like enzymes or by natural physical methods like field and water retting.
  3. Once the fibres are separated, they are spun together to produce long and continuous yarn.

At this point, the long continuous yarns can then be twisted together in hundreds of different ways, and woven or knitted together to create a fabric. The fibres can also be blended with other fibres like cotton and silk for example, to create a fabric with different properties.  Usually, the fabric is then washed and shrunk, so the weave can tighten up. A fabric made entirely from hemp can usually be quite stiff and heavy. It can feel abrasive on the skin, and so requires softening before it is used in garments. Chemical softening methods include processing with caustic soda or acid rinses. The Organic method employs refined combing technologies and also biodegradable softening solutions.  If the yarns haven't been dyed beforehand, the fabric is dyed and stabilised by treating it against shrinkage. This also creates a finished appearance.

For a more in depth look at industrial hemp production, I'd recommend a look at this site written by the government of Manitoba, Canada. The content is specific to the climates of Manitoba, but the processes are generally the same globally.

Pros and Cons of Hemp Fabric

PROS

Hemp is a superior fibre that holds its shape and is incredibly strong. Hemp, like linen, becomes softer with use. It is porous and hence water absorbent. Hemp is a breathable fabric that can keep us warm in winter and cool in summer. It's particularly good in hot climates because it resists degradation by heat, and is less prone to fading. One particularly unique advantage of this fibre is that it effectively blocks UV rays. UV rays are a major cause of cancer, so anything that helps to combat this is great by me. It is hypoallergenic and hence suitable for people with sensitive skin. Hemp absorbs dyes well, and also has a naturally high lustre - it is possible to make hemp fabrics that truly shine, such as this hemp silk charmeuse (image below). Finally, when it comes to disposing the fabric, the fibre is completely biodegradable.

CONS

A characteristic feature of hemp is its abrasive nature. Due to this, it does not feel soft against the skin. However, it can be blended with other fibres to give it a soft hand. Garments made entirely from hemp tend to wrinkle easily, because, like linen, its elastic recovery is very poor. Another thing to note is that while it resists degradation in heat, hemp fibres can be attacked by fungi and bacteria under hot and humid condition. Mildew rots and weakens the material. This can be avoided by impregnating the fabric with chemicals such as Copper Nepthenate.

Hemp: Environmental Benefits

Hemp helps detoxify and regenerate the soil where it's grown. Apart from the natural benefits of falling leaves replenishing the soil with nutrients, nitrogen and oxygen, hemp roots absorb and dissipate the energy of rain and runoff, which protects fertilizer, soil and keeps seeds in place. More astonishingly, it can also pull nuclear toxins from the soil! As I mentioned, hemp was in fact planted around the site of the Chernobyl nuclear disaster, to help clean the polluted sites. This process is called phyto-remediation. Phyto-remediation can be used to remove nuclear elements, and to clean up metals, pesticides, solvents, crude oil, and other toxins from landfills. Hemp breaks down pollutants and stabilizes metal contaminants by acting as a filter. Hemp is proving to be one of the best phyto-remediative plants found.

The minimum benefit of a hemp crop is in it's use as a rotation crop. Since hemp stabilises and enriches the soil that farmers grow crops on and provides them with weed-free fields, without cost of herbicides, it has value even if no part of the plant is being harvested and used. Any industry or monetary benefit beyond this value is a bonus. Rotating hemp with soy reduces soy-decimating parasites, without any chemical input.

Hemp can grow in any agronomic system, in any climate. All hemp products are completely biodegradable, recyclable and hemp is a reusable resource in every form: pulp, fiber, protein, cellulose, oil, or biomass. As well as this, it requires no herbicides, pesticides, fungicides, or insecticides to grow well, as it is its own fertilizer, its own herbicide and its own pesticide - as it is technically a weed. Hemp plants only need 10-13 inches of water to grow to eight to twelve feet in three to four months - this is a third of the amount which cotton requires.

This just scratches the surface of the environmental benefits of hemp. If you'd like to know more, I'd encourage you to check out this pdf too.

Hemp: The Ideal Eco-Fashion Solution

From the various properties of hemp, we can easily conclude that it is a fabric with excellent scope for sustainability. Not only is the crop organic, it is also cheap and environmentally friendly in almost every aspect. Unlike non-organic cotton which immensely contributes to environmental pollution, energy and water use, hemp is eco-friendly and even benefits the soil and air where it is grown.

Something to note is that the processing techniques followed during the softening, cleaning and finishing of hemp may involve chemicals. Synthetic dyes containing heavy metals may be used for dyeing and chlorine is commonly used in the cleaning stage. Chemical processing with heavy caustic sodas and acid rinses are the techniques followed to improve softness and clean the fibre.

At Offset Warehouse, we're incredibly diligent when it comes to sourcing all of our fabrics. When it comes to our hemp fabrics, bleaching is done using peroxide bleach and the softening with cationic, which is water soluble. All of our dyes are fibre reactive low impact dyes. We use a closed loop process to create the fabrics and any water that exists the factory must be purified using a government approved purification system. All of our factories have social benefits. The unit that produces our hemp silk charmeuse, for example, offers their workers paid maternity leave, apartments that the workers will own at retirement (similar to the American Social Security System), daycare, health care and schooling up to the age of six for their children.

The possibilities for hemp as a fabric are yet to be fully uncovered. This versatile crop has immense potential to be elevated as the ideal fashion choice for interiors and clothing. Why not explore the interesting possibilities that this superior fabric throws open in your own work? By opting for this unusual fibre with such immense environmental benefits, you'll pass on these incredible, longstanding benefits to your own customers, and create a more sustainable business for yourself in the process.


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Turning Hemp into Fabric: Amazing facts, the pros and cons and more!