Connect with Unisnap

Colombo - Level 1, Office No. 08, Liberty Arcade (Next to Liberty Plaza Building), 282 R A De Mel Mawatha, Colombo 03

Unisnap Hotline

Denim fabrics are generally made from staple-fibre yarns where the weft passes under two or more warp fibres, producing the familiar diagonal ribbing identifiable on the reverse of the fabric. Indigo is the most common denim, where the warp thread is dyed, while the weft thread is left white. Because of the warp-faced twill weaving, one side of the denim fabric is dominated by the blue warp threads and the other side is white weft threads.

Denim is a sturdy cotton warp-faced textile in which the weft passes under two or more warp threads. Denim was produced on very similar base of dungaree fabric that was already been produced in India for hundreds of years.

The word ‘denim’ derives from French serge de Nîmes ‘serge from Nîmes’.

popularity increased with time and Davis moved his production to Levis Strauss & co. who were supplying the bolts of denim fabric.

Throughout the 20th century denim was used for cheap and durable uniform for many working class people all over the world, it was a mark of lower working class, these were a one piece garment, with long legs and sleeves, buttoned from throat to crotch, in an olive denim fabric.

All denim is created through generally the same process:

  1. Cotton fiber is spun into yarn
  2. Some of the yarn is dyed, some left white
  3. The yarns are woven on a shuttle loom or projectile loom
  4. The woven product is Sanforized

YARN PRODUCTION

Most denim yarn is composed entirely of cotton. Some denim yarn may use an elastic component such as spandex for up to 3% of the content to allow the final woven product to stretch. Even such a small amount of spandex enables a stretching capacity of about 15%.

DYEING

Denim was originally dyed with indigo dye extracted from plants. In south Asia indigo dye was extracted from dried and fermented leaves of Indigofera tinctoria, also known as natural indigo. However mostly the denim today are dyed from the synthetic dye. In all the cases the yarns undergo a repeated sequence of dipping and oxidation, the more the number of dips, the stronger the colour of indigo.

Prior to 1915, cotton yarns were dyed using a skein dyeing process, in which individual skeins of yarn were dipped into dye baths. Rope dyeing machines were developed in 1915, and slasher or sheet dyeing machines were developed in the 1970s; both of these methods involve a series of rollers that feed continuous yarns in and out of dye vats. In rope dyeing, continuous yarns are gathered together into long ropes or groups of yarns– after these bundles are dyed, they must be re-beamed for weaving. In sheet dyeing, parallel yarns are laid out like a sheet, in the same order in which they will be woven; because of this, uneven circulation of dye in the dye bath can lead to side-to-side colour variations in the woven cloth. Rope dyeing eliminates this possibility because colour variations can be evenly distributed across the warp during beaming.

Denim fabric dyeing are divided into two categories: indigo dyeing and sulfur dyeing. Indigo dyeing produces the traditional blue color or shades similar to it. Sulfur dyeing produces specialty black colors and other colors, such as red, pink, purple, grey, rust, mustard, and green.

WEAVING

Most denim today made is on a projectile loom, that produces bolts of fabric 60 inches or wider, but some of the denim is still woven traditionally on shuttle looms, which typically produces 30 inches wide fabrics. Shuttle loom woven denim is typically recognized by its selvedge. The edge of a fabric created as a continuous cross-yarn (the weft) reverses direction at the edge side of the shuttle loom. The selvedge is traditionally accentuated with warp threads of one or more contrasting colours, which can serve as an identifying mark.

Although quality denim can be made on either loom, selvedge denim has come to be associated with premium products since final production that showcases the selvedge requires greater care of assemblage.

The thickness of denim can vary greatly, with a yard of fabric weighing anywhere from 9 to 32 Oz, with 11 to 14 Oz being typical.

Processing

Many denim articles are washed to make them softer and to reduce or minimize shrinkage even beyond what sanforization prevents. Significantly washed denim can resemble dry denim which has faded naturally over extended use. Such distressing may be supplemented by chemical treatments or physical techniques such as stone washing.

Over the years, quite a few forms of denim have been developed.

  • Raw denim

This type of denim has not been washed or treated. Generally, it is worn for six months to a year without washing to make sure it forms to the wearer’s body. Raw denim enthusiasts often resort to putting their jeans in the freezer overnight to kill off microbes and bacteria.

Often available in darker shades. Nowadays the raw denims are washed for softness and for reduced shrinkage. Can be identified through the white yarns in between.

  • Sanforized denim

Most types of denim have been Sanforized, which is the washing process that has resulted in modern denim fabric. While Sanforized jeans are softer, they are also less durable, and they aren’t as personalisable as raw denim jeans.

  • Stretch denim

With this type of denim, cotton has been mixed with spandex or a similar material. The resulting fabric is stretchier than normal denim, so it is commonly used in form-fitting applications like skinny jeans.

  • Crushed denim

This type of denim features a weave that’s similar to velvet. It has a permanently wrinkled appearance that makes it appealing for jackets and skirts.

  • Selvedge denim

It features a narrow, tightly woven band on both edges of the denim fabric which, one, prevents it from unravelling and, two, shows a clean finished look. The word selvedge comes from “self-edge”, as the edge of the denim has a clean finish and comes on a 32” this fabric is commonly used to make jackets.

  • Acid wash denim

This type of denim features an iconic mottled appearance. It’s made by washing raw denim in a strong acid that eats away at the dye.

  • Poly denim

The term “poly denim” is widely used to refer to denim products that are made with a mix of cotton, polyester, and any number of other artificial fibers. Along with polyester, materials like lyocell and nylon are sometimes added to cotton to make denim products. Some purists would say that poly denim is not “real” denim.

  • 100% cotton denim

These are the original form of denim, from the 19th century these were developed for the hard working section of wagers, who wanted clothes that were hard and long-lasting. These are made from cotton with no synthetic materials involved.

Denim Fabric Finishing

Denim fabric finishing are those which are carried out after weaving and conclude with the quality control checking of the fabric or garment manufacturing. They consist of:

  1. BASIC OPERATION

The basic operation is always carried out on the denim fabric just after the weaving process. They are required for the correct physical behaviour of the fabric when it is subject to posterior operations such as tailoring. Final garment finishes as well as domestic laundering once the garment reaches the consumer

2. BRUSHING AND SINGEING

Treatment of a still sized fabric recently out of the loom. It consists of the elimination of those superficial fibres which give the fabric a fluffy look. Brushing and singeing are consecutive operations.

During the operations fabric is subject to a superficial combustion of the fibres with a gas flame at elevated speed (specifically adjusted so that the fabric does not suffer any deterioration or damage). After singeing a posterior washing is carried out in order to clean the fabric.

  • 3. SANFORISING

Sanforizing is a textile finishing treatment, also called Sanfor treatment, carried out in the piece in order to increase the dimensional stability of the fabric when washing, or to prevent the fabrics from shrinking during washing.

The process of pre-shrinking a fabric so to a limit the residual or further shrinkage of the fabric to less than 1%.

This sanforization process involves the stretching of the fabric before it is washed, which helps to prevent shrinkage. Sanforizing is a mechanical finishing process of treating textile fabrics to prevent the normal dimensional alternation of warp and weft. It is also called anti-shrinkage finishing process.

A pressure between the cylinder and the rubber the where the shrinkage of the fabric take place, where the warp thread is joined and evenly shrunk.

4. STENTER

It is the operation that is performed on the denim type fabrics, which contain a percentage of elastomeric fibre in their structure (generally in the weft). This way it is possible to possible to control the fabric’s free elasticity, which stays preset adjusting and controlling the final shrinkage of the fabric. That is why the fabric, stretched and held by the needles or pins, circulates through a series of chambers at elevated temperature. Before the fabric enters the chambers it can be impregnated in the squeezing mangle with a solution, like for chambers it can be impregnated in the squeezing mangle with a solution.

5. SPECIAL DENIM FABRIC FINISHING

These operation give the final fabric certain physical properties contributing to the garment appearance comfort. At present there different possibilities in this field such as:

  • Chemical finishing: by using chemical products like binders, softeners etc. to enhance special hand feel properties of the denim fabric.
  • Coloured finishing: by using chemical products along with pigment dispersions in order to give the denim fabrics certain fashionable properties developed in garment finishing. Other range of dyes such as sulfur dyes or direct dyes can also be used in these recipes.

The most often applied techniques for denim fabric finishing are the following:

  1. Knife coating application
  2. Rotary screen coating application
  3. Dyeing trough padding application

The finishing recipes in techniques 1 and 2 can be prepared both in the form of paste as well as foam.

These products are applied on the fabric in liquid form in liquid form in case of padding application. Nowadays, denim fabric finishing has become extremely important for denim quality differentiation as it gives as it gives and added value to the fabric.

6. SPECIAL GARMENT FINISHING

Mechanical or physical effects on garment (dry denim processing) Grinding, tagging /clipping, damages/ breaks, tie effects

Making up

Weaving of the fabric on such multi sizes is not economical, hence a standard width fabrics is then sent to making up. Fabrics are cut into the desired width as per size required on this machine. Denim fabric and grey fabric are thoroughly checked for various types of defects such as:

  • Weaving defects
  • Uneven dyeing
  • Bleaching and dyeing defects
  • Oil stains
  • Patches

7. DISPATCH

Rolls and sets so formed and packed as per buyers requirement are then sent for final dispatches.

Denim produced under the concept of reach related cellulose-based DENIM provides great results with comfort in uses they have been studies regarding the same which focuses on developing A comfortable product with maintaining the same original rugged look. Regenerated fibres are produced from natural origin such as wood pulp.

Very good tensile strength, bright appearance and soft feel are exhibited by such cellulosic fibers. These are resistant to wear and have smooth hand. Besides imparting comfort in moderate conditions such products can transfer moisture well and enable comfort during wear in hot, moist climatic conditions. The percentage of moisture in the fiber is determined by the cellulose content, leading to cooling sensation when in contact with the human body.

The properties studied include tensile, bending, shear, compression and surface properties.

Improvement In Denim

There are major aspects in which the innovation and development can be done in the Denim, comfort performance and environment friendly can be achieved in the different processes of manufacturing denim. Comfort and fit are very important aspects of denim garments. So, a lot of research has being done to make stretch denims.

Elastane fibers are incorporated into the fabric. Lycra and Spandex are used in weft yarn. Ring and open- end core spun yarns are also used in denim to provide stretch property. Elastic ply yarns produced on TFO are also used to make stretch denim fabrics. Apart from the multi-component, Bi component synthetic filament yarns are also used to provide stretch.

To improve performance

Synthetic fibers blended with natural fibers are used. One of such blends is blend of Nylon 6.6 and cotton. This fabric shows the traditional look and feel but performance is better than the 100 per cent cotton denim in

terms of better abrasion resistance. So, the durability of the fabric is more than the 100 per cent cotton denim. Other synthetic fibers such as polyester and polypropylene fibers are also used. For making softer denim fabrics especially for women wear, blend of Cupro, Modal, Promodal, Tancel, and Rayon are being used. Bamboo fibers, hemp fibers and their blends are being used to make denim fabrics.

To impart a fancy effect

  • Different kinds of fancy yarns are being used. Examples of such yarn are slub yarn and multi-count yarn. The Slub can vary in terms of thickness, length and twist. Such yarns can be manufactured at ring spinning and OE spinning machines by attaching special attachment. One of such attachments is Amsler control. Such fabrics give a very unique effect after washing treatment.
  • Two methods of warping are practised. These are ball warping and direct warping. Dyeing of warp yarns is done either by rope dyeing method or Slaser dyeing method. Rope dyeing is considered better in many aspects such as higher production, long runs, better dry and wet fastness and lot-to-lot shade consistency. Indigo dyes are generally used to dye warp yarns. In some cases sulphur black and blue dye can also be applied before indigo dyeing to achieve darker shades. Sometimes, sulphur dyes are also applied after the yarn is indigo dyed.
  • Denim fabrics are mostly woven on high-speed air-jet looms. Various loom manufacturers are offering a number of modifications to weave fault free high quality fabric. The modifications are done in the frame structure of the loom to minimize vibrations, pre-winder, auxiliary nozzles, stretch nozzles, relay nozzles and weft brake system. Traditionally denim is 3/1 right-hand twill fabric. Nowadays 2/1 twill, broken twill, zigzag twill, reverse twill, Herringbone twill weaves are used in denim fabrics.

Desizing of fabrics

Desizing is done after weaving. This process can be done by acid desizing method and oxidative desizing method. But these processes are associated with a number of disadvantages. To overcome this, enzymatic desizing is preferred. Alpha- amylase is used as desizing agent. Enzymatic process are more eco-friendly than chemical methods.

Washing of denim

Washing of denim garments is one of the most important processes. This process adds a lot of value to the final garment. In the washing process, fading effect is imparted to the denim products. There are many methods to impart faded effects. The traditionally washing is done using any of the methods or combinations such as stone washing, washing with strong bleaching agents such as sodium hypochlorite, potassium per magnet. These processes are not environment friendly. Alternative methods have been developed. Cellulases enzymes are used in place of pumice stone to impart abraded effect.

Laccase based bleaching technique is developed. This enzyme only attacks indigo dyed yarn bit does affect nature of white weft yarn. It can also be used to bleach fabrics containing elastane filaments without losing stretch property. Laser based techniques are used to give faded effect. Further this technique can also be used to create motifs on the denim fabrics. Ozone base denim washing treatments have been developed. In this process, ozone gas is used as bleaching agent, which attacks indigo dyes and destroy to create faded look.

Functional finishes

such as antibacterial finishes, UV- protection finishes are applied on denim fabrics to improve functional performances of denim fabrics. To enhance the durability of the finished fabric, nano encapsulation of the herbal extracts were performed and the results showed good resistance for microbes even after 30 industrial washes. The use of nano-clay is also reported to impart old look, soft handle, flame retardant and antibacterial properties to denim fabrics.

Effects Of Denim Mnaufacturing On The Environment

According to various studies it is found that textile industry are one main producers of water pollution, especially in the south eastern asia , countries like india, Bangladesh china, etc.

Listed here are some of the problems associated with its production followed by possible solutions:

Consumption of water

Used for the cultivation of denim fabric main ingredient, cotton. It’s a fibre that is heavily irrigated and fertilized, and additionally, it uses large amounts of water in its manufacturing and packaging processes. The finishing processes employed – which include dyeing, washing and special visual effects, such as stone-washing – also consume vast quantities of water, resulting in denim manufacturing with a high-water footprint. Incredibly, one pair of jeans, including its production and general wear uses up to 2,900 gallons of water.

Water pollution

The three processes that cause water pollution are the growing of cotton, dyeing and finishing the material and texturizing and finishing the product.

The dyeing process of the yarns includes multiple times of immersion in water, whether chemical or natural dyes the tons of water is used up in different levels of the process.

It’s a natural occurrence if herbicides and chemical pesticides are used so prolifically. Their use contaminates the soil and water sources and can cause detrimental health effects to cotton farmers.

The use of chemical dyes in the production of ‘distressed’ denim is intensive. The denim is subjected to several chemical washes. Added to that, there are serious health risks to the workers through exposure to the harmful chemicals that are used to spray the material in pursuit of an ‘ acid wash’. Chemical run-offs from some of these manufacturers are also dumped into the water system, turning them indigo-blue such as the Pearl River in China.

Denim Sandblasting

This process involves taking fine sand and channelling it into an air gun, it is then sprayed at high pressure onto denim to create a worn, old look. It’s a cheap, quick method that manipulates garments but its main ingredient, silica, is harmful to workers.

Non-biodegradable denim

The newer versions of denims , in order to be stretchable and formfitting the yarns while being spun are included into the yarns, materials like spandex , elastane are included , also cheaper version of denims includes polyester yarns , now these denims after usage , are often left untreated and are harmful to the environment and just add to the problems.

Potential Solutions

The Better Cotton Initiative has supported farmers in their move to reduce water usage by 39%. They are uniting farmers, ginners, traders, spinners, mills, manufacturers and retailers in a unique global community that is committed to developing Better Cotton as a sustainable mainstream commodity.

Drip irrigation– Is a type of micro-irrigation that has the potential to save water and nutrients by allowing water to drip slowly to the roots of plants, either from above the soil surface or buried below the surface. The goal is to place water directly into the root zone and minimize evaporation.

Innovations in dying technologies developed by Bluesign, an endeavour that helps the textile business to produce in an environmentally friendly and resource-efficient way combining both the economic and ecological advantages to the benefit of everyone involved.

  1. Shopper education such as using a washing machine less often to wash your denim and perhaps considering sponge cleaning them occasionally.
  2. The production of organic cotton uses natural techniques to ward off insects. Natural indigo dyes could be used as well as Archroma advanced denim technology; an innovative dyeing process that uses sulfur dyestuffs that bond more easily.
  3. Computer-driven laser technology can replicate localized wear and whiskers, without the use of water, chemicals or stones. Lasers offer precise, repeatable bleaching effects that are more controlled. However, equipment is expensive, each garment must be individually positioned for treatment, and only one side can be treated at a time. It’s excellent for creating smaller effects but is less beneficial for overall bleaching.
  4. Ozone Technology harnesses the natural bleaching capabilities of ozone gas to give a range of overall and specialty bleaching effects with substantially reduced environmental impact. Ozone can be used to clean pocket back-staining from normal washing processes or to bleach denim to a lighter shade. Ozone does not eliminate water use in jeans finishing. However, it substantially reduces the consumption of water as well as energy, chemicals, enzymes and stones.
  5. An emerging greener chemistry process, called Advanced Denim by Archroma, can produce a pair of jeans using up to 92% less water and 30% less energy than conventional methods. In addition to this, it generates 87% less cotton waste and no wastewater. Unlike conventional denim production methods, which require up to 15 dyeing vats and an array of potentially harmful chemicals, Advanced Denim uses just one vat and a new generation of eco-advanced, concentrated, liquid sulfur dyes that require only a single, sugar-based reducing agent. All other production steps are also eliminated.

Denim fabric certifications available

  1. Global Organic Textile Standard (GOTS)
  2. Supima certification
  3. Cradle to Cradle

This group makes sure that natural textile manufacturers follow strict sustainability and safety standards.

DENIM AND SUSTAINABILITY

Denim comes to mind. On the surface, denim is far from the most sustainable textile used in the production of clothes. A single pair of traditionally-made jeans has required an embarrassing amount of chemicals, thousands of litres of water and energy consumption that has been almost comically outsized compared to the finished product. But things have changed and today denim is produced in more responsible ways—ways that use less water, fewer chemicals and less energy (hydro-less denim).

There are denim brands and other fashion designers that are taking a more sustainable approach to their manufacturing processes.

  1. Everlane, the e-tailer and stalwart of sustainability and transparency uses the Saitex factory for the production of their denim jeans. It is housed in a LEED-certified facility that recycles 98% of its water, relies on alternative energy sources, and repurposes by-products to create premium jeans-minus the waste. Through its commitment to renewable energy resources like solar power, Saitex has reduced its energy usage by 5.3 million kilowatts of power per year – and reduced C02 emissions by nearly 80%. Eighty-five per cent of the jeans produced in the factory are air dried and then briefly finished, for softness, in a commercial dryer. All denim production creates a toxic by-product called sludge. At Saitex the sludge is extracted and shipped to a nearby brick factory. It is then mixed with concrete and converted into bricks that are used to build affordable homes.
  2. With the help of expert textile manufacturers Arvind Mills, who Pratap Singh worked with to create his range of lovely khadi jeans, the designer says he wants to take the best quality of indigo denims from India across borders, showcasing the country’s strong ties to the blue hue; in fact, the Greek word for the dye, indikón means ‘Indian’.

Joining Pratap Singh in the use of Indian khadi is Levi’s, with the brand’s latest denim collection, woven by hand, displaying the weaver’s name and the location where it was produced.

The khadi denim fabric is made from hand-spun yarn, on manually operated handlooms. The entire process of making the fabric is carried out without using electricity and without burning any kind of fuel. The khadi denim fabric comes with a neat and clean selvedge, has a very interesting texture, and is very comfortable to wear. The high breathability of the fabric makes the wearer feel cool in summers, and warm in winters. Khadi Denim is woven using 100% cotton hand-spun single ply yarn in warp, or in both warp and weft, in the 3×1 twill weave. The fabric has a unique and unmatched richness in surface texture, owing to the uneven-ness of the hand-spun yarn.

3. E.L.V. Denim

In addition to selling her reworked jeans at top retailers and conscious platforms like Rêve En Vert, E.L.V.’s Anna Foster is preparing to introduce a new made-to-measure program where customers can visit her studio and have a pair of jeans made to their exact specifications. The service is set to become available on a small scale as soon as London’s quarantines are lifted. Foster is confident that the coronavirus—coupled with the looming climate-change crisis—will shift consumer habits for the better. “I hope this pause in our economy will at least allow consumers to look past the easier options and find smaller, locally produced, ‘kind’ brands,”

4. DL1961

Along with lower-impact cellulose fibers, DL1961 jeans are crafted from certified-organic cotton and use clean indigo dyes that reduce water use and create no harmful byproducts. The vertical integration of its factories also means there’s less shipping and packaging involved in manufacturing each pair of jeans, reducing both DL1961’s carbon emissions and, ultimately, the cost passed on to the customer

5. Ética

Los Angeles label Ética counts itself as one of the only manufacturers to be certified for global impact, clean industry practices, and social responsibility. They’ve committed to above-average labor standards and avoid using toxic chemicals in their supply chain; to wit, these sherbet tie-dye jeans were dyed with plants like bougainvillea, chrysanthemum, and natural indigo.

6. Bliss and Mischief

Hillary Justin started her label, Bliss and Mischief, by reworking vintage jeans with Western motifs and gigantic rose embroideries, and they were such a hit that she was able to expand into a full line of T-shirts, jumpsuits, and knits. In 2017, she introduced brand-new jeans that fit like vintage, dubbed the Collector Fit. They were an instant success—though they weren’t exactly new. Every pair was (and still is) made from deadstock denim sourced locally in Los Angeles. Like any vintage pair, they get better with age; as her website says: “BAM denim is meant to be worn…and to be loved.”

7. Boyish Jeans

Also in Los Angeles, Jordan Nodarse founded Boyish Jeans as a resource for vintage-inspired jeans that are kind to the earth. His jeans are made with certified-organic and vegan materials like cotton and Tencel and plant-based dyes that use less water, and he often incorporates deadstock materials as well.

Paris label Sézane is beloved for its affordable, vintage-inspired jeans, but founder Morgane Sezalory is newly focused on sustainability. She recently pivoted all of her denim production to include 100% GOTS-certified organic cotton, eco-friendly washing, recycled water, and laser detailing in lieu of chemical treatments. They still have the “shaping effects” of her original jeans and are nicely priced at $125.

8. Citizens of Humanity

Citizens of Humanity is the favorite designer denim label for many fashion editors, both for its fashion-forward silhouettes and soft, high-quality denim. There’s always a new jean to love, but the brand’s new organic-cotton

collection is a particularly exciting development. Some of Citizens’ most popular fits, like the Annina trouser, now come in 100% organic cotton and use water-saving, energy-reducing technology. Citizens of Humanity also owns two other denim labels, Goldsign and Agolde, which are making similar strides in organic fabrications, laser treatments, and ozone washes, which reduce energy and water consumption.

9. Gap BetterMade Denim

The American label is making sustainability a priority these days, starting with a new BetterMade capsule of organic-cotton denim produced by Candiani, an Italian mill that implements water- and chemical- reducing dying and washing technologies. Gap says it’s their most sustainable denim yet.

Conclusion

Denim has been around for a very long time now, the fabric has been constantly evolving as per the need of the time. It started as a durable fabric material for uniforms for working class laborers and then in 20th century it became a symbol of modern fashion and liberation of women’s. Denim is liked by all irrespective of gender, age and profession. A lot of innovation and research are to be done on continuous basis to fulfill requirement of diverse consumers keeping in mind its impact on environment and society.

Denim is a quality product and is multipurpose it can be used as a garment and clothing as well as package or covering. It’s a diverse material with multiple type each with a unique quality. Denim has a lot of scope and if used consciously can create a great scope for humanity.

We have amazing opportunities to promote and appreciate the national and local handlooms in combination with denim ex; khadi denim which promotes sustainability and supports national local wagers.

One of the best ways to shop in a sustainable way is to do so within the circular economy, prolonging the life of garments and keeping them out of landfills that much longer. Also since denim is durable fabric hence we can easily up cycle denim.

Bibliography


About the author

Harshit Prajapati
(@hahahahahaharshit) • @prajarty,
Bachelor of Design,
National Institute of Fashion Technology)

Leave a Reply

Your email address will not be published. Required fields are marked *

15 + = 20