COTTON, BACK TO ITS ROOTS
Temps de lecture : 3 minutes
COTTON, BACK TO ITS ROOTS
Poplin, denim, flannel, oxford, yarn, twill... all these materials are made from cotton yarn woven in different ways. But what are the preliminary steps from the harvest to the finished fabric? We explain everything in this article, follow the guide!
The raw material
Cotton plants, shrubs of the Malvaceae family, grow in tropical regions: they need deep and fertile soil, 120 days of rain per year and a lot of sunlight to grow well. They produce fruits composed of capsules divided into 5 to 8 lodges. Each compartment contains 5 to 7 seeds and each seed is covered by a vegetable fiber made of pure cellulose: cotton. There are several varieties of cotton plants, of which two are the most common: Gossypium hirsutum and Gossypium barbadense.
Gossypium hirsutum represents 81.5% of the world fiber production, and Gossypium barbadense represents 6%. The latter was introduced in Egypt where it is cultivated and is considered today as one of the best cottons in the world for its quality and the length of its fibers.
Gossypium hirsutum
Gossypium barbadense
Cotton is mainly produced in China, India and the United States. Traces of its cultivation dating back 7000 years have been found in Mexico and others dating back more than 3000 years in India.
History of cotton
Its name comes from the Arabic word al qutun. It is woven in India to make clothes and raw cloth. These are sent to be dyed in Europe, which is passionate about this material. The French East India Company founded in 1644 imported "indiennes", painted cotton fabrics, which were very fashionable. Then the industrial revolution saw the appearance of tools that would industrialize production: mechanical ginning, the first spinning machine with several spindles: the Spinning Jenny, then the combing and spinning machine and finally the synthesis of these two crafts with the Mule-jenny with a productivity 40 times higher than the spinning wheel.
Spinning Jenny
Mule-Jenny
In 1801, Jacquard invented the first automatic weaving loom that worked with large perforated cards and allowed the creation of various patterns.
Jacquard loom
The cultivation of cotton developed in the United States at the beginning of the 17th century. The work in the plantations unfortunately favors slavery and the black slave trade.
Today, cotton is still widely used worldwide. It represents 37% of the world's textile fiber production with 25.5 million tons per year and 2 to 3% of the world's cultivated areas. However, it has been overtaken by synthetic fibers made from petroleum-derived polymers such as acrylic, polyester or polyamide.
The characteristics of cotton
Its qualities :
Absorbent: cotton fibers have a strong absorbent power, they can absorb up to 8.5% of their weight in water, which explains why we use this fiber in large majority for the manufacture of bath linen.
Insulating: a fluffy surface is obtained by scraping cotton. This material holds heat close to the body and is used, for example, to line the inside of zip-up hoodies.
Scraped cotton
Easy to maintain: it supports high temperatures for washing (it can be boiled) and hot iron ironing
Inexpensive because easy to produce
Soft, supple and comfortable. Silky feel.
Hypoallergenic: very low allergenic, textile preferred for babies
Breathable: cotton allows air to pass and facilitates skin breathing
Easily tinted or printed
Despite all its qualities, cotton is sensitive to moisture and develops molds if it is improperly stored, it loses its colors over time. It is less solid than linen and less elastic than wool. However, its resistance increases when wet. It is also highly flammable.
The steps: from seed to fabric
Cotton goes through several stages from its cultivation in the fields to the finished product: cultivation, harvesting, ginning, spinning, weaving, dyeing.
Harvesting and ginning: separating cotton fibres from the seeds around them
Drying: let the cotton dry in the sun then remove the debris
Spinning: we turn cotton into yarn. The spinning is carried out in several phases: the cotton is cleaned of its impurities thanks to specialized machines, then it is combed, stretched and transformed into ribbon according to the procedure of the carding. It is then twisted and pulled until a continuous wire is obtained. The torsion is more or less important depending on the quality one wishes to obtain.
Dubbing: it is an optional step, it allows to strengthen the thread by doubling or tripling. A doubled thread is called a double twist
Dyeing: dye the yarn with the use of colouring substances or, conversely, bleach it
Weaving: we cross the threads to make a fabric. The type of weaving is called a weave, which will give a fabric more or less thick, more or less soft, and work according to the chosen interweaving… (poplin, denim, twill, thread to thread…) For this we use a loom that holds the warp threads in place and allows us to thread the weft threads through them.
Loom
Finishes: the resulting fabric is subjected to several treatments to improve its dyeing and its final appearance.
Some cottons are mixed with synthetic fibers such as polyester, which makes it more harmful to the environment and of lower quality. We prefer 100% cotton materials.
The environmental challenges of cotton
The cultivation of cotton has a negative impact on the environment because it is a heavy consumer of water and chemicals. In addition, cotton dyeing requires the use of toxic heavy metals such as lead or chromium.
For a single cotton T-shirt, you need an average of 25,000 liters of water and 5.2 kg of CO2.
Working conditions in emerging countries also remain very difficult.
We are now turning to organic cotton production as part of fair trade, but this is still anecdotal. The GOTS Global Organic Textile Standard label guarantees organic cotton production based on environmentally friendly and fair trade methods. For example, the pesticides used are natural (manure for fertilizer, no GMOs, etc.). This organic cotton is even more pleasant to the touch thanks to the absence of chemicals.
Finishes: the resulting fabric is subjected to several treatments to improve its dyeing and its final appearance.
Some cottons are mixed with synthetic fibers such as polyester, which makes it more harmful to the environment and of lower quality. We prefer 100% cotton materials.
