Jitender Kumar,

Vice President – Raw Materials (Fibres),

Sutlej Textiles & Industries Limited, Mumbai.

Email: jitenderkumar@sutlehtextiles.com

(Intro)The plethora of innovations at the level of fibres and their blends, yarn types, stretch fibre content, weaving techniques and fabric constructions are all contributing to making denim an even more desirable fabric ranking high on fashion and performance.

A ‘sturdy fabric’ possibly driving its origins from France with a close predecessor named dungaree from India, denim is most commonly an indigo dyed cotton textile. With around half of the population on earth wearing it at any given point of time, this classic indigo blue fabric is considered to be unique and has evolved to be a fabric of the masses and a quintessential American garment.

With the demand of denim continuing to grow, the annual global production of denim is 15 billion metres with half of the production coming from Asian countries like China, India, Turkey, Pakistan and Bangladesh. China is the largest exporter of denim accounting for around 64% of the world’s total, followed by Pakistan. The market share of denim in cotton fabric imports by volume has ranged from 21% to 24% in the last 5 years and its market share in cotton fabric exports by volume ranged from 14% to 26% in the last 10 years. With a current market size of around US$ 57.3 billion in 2020, the market value is projected to reach US$ 76.1 billion in 2026 growing at a CAGR of over 4.8%.

Since today’s discerning customers of denim clothing desire lot of aesthetic appeal, fit, wearing comfort, performance, and sustainability in all aspects of its production, numerous developments in fibre and textile technology are offering newer concepts in denim. Conventionally produced from 100% cotton and dyed from natural indigo, today’s denim is a highly transformed new generation fabric. The highly supple fashion denims are now draping diverse body shapes.They are available in different variants (stretch to bio-polished), colours (vegetable-based, indigo to sulphur dyed), fibre blends (most recent being softer, lighter, comfy silk for all weather denims),textures, drapes and avatars fitting the recent ‘athleisure’ trend.

The more recent and an almost universal escalation in cost of raw materials and logistics to decadal highs has necessitated the denim industry to innovate at all levels to maintain margins and contain the rising prices of the products. The denim manufacturers across the world have been employing various methods and reverse engineering techniques to stay afloat and make their products more cost effective. These measures include reducing the weight of the fabric, reducing fabric lines to improve plant efficiency, skewing the product mix towards more profitable technical fabrics,exploring different dye combinations and a shift to less expensive lighter shades, working with various blends of cotton and man-made fibres like polyester, modacrylic, aramid and stretch,increased use of recycled cotton, recycled polyester and use of newer methods,digital age machines and automation to save on energy and water to offset the higher prices of fibres and other inputs.

The most important innovations in denim have been the use of new fibres and new fibre blends.

Stretch (synthetic elastic fibres known as spandex in the US and elastane elsewhere) fibres blended with cotton have been revolutionising the entire denim landscape.Lycra as the branded stretch fibre offers lasting stretch for fit, shape and comfort and delivers clothes that move with the body. Lycra T400 fibre provides spandex-free stretch and bounce-back recovery for exceptional shape retention. The patented Lycra dualFX technology goes further by providing two stretch fibres – spandex (elastane) and a polyester bi-component fibre (Lycra T400) for unparallel denim performance which includes high stretch and high recovery and exceptional dimensional stability. A bi-stretch denim with spandex spun into both warp and weft is another important innovation.

Besides synthetic fibres like Polyester and polypropylene normally used in denim fabric, a lot of different performance denim concepts are being realized by blends of cotton and synthetic fibres like high strength Invista nylon 6,6 resulting in an engineered Cordura denimfabric known for its durability, comfort, hard-wearing and an additional resistance to abrasion keeping the jeans looking new longer.A combination of Cordura staple nylon 6.6 Black SDN fibre and spun dyed Lenzing Tencel Modal fibres with Eco Color technology is rendering black color to denim fabrics at the fibre level resulting in very effective color consistency, fastness and retention.

Kevlar as a synthetic aramid fibre provides exceptional strength and heat resistance and forms an important mix with cotton to impart added strength to the denim fabric and increased durability. Dyneemafibre when blended with cotton delivers light weight yet exceptionally strong, durable, abrasion and cut resistant yarns which may be knitted or woven into denim fabric for outdoor, sports and fashion industry.

Cotton, generally coarser in fineness (micronnaire) and shorter in staple length (ranging from 22mm to 27mm) remains the major cotton type for spinning yarns suitable for denim fabric.As an important innovation, finer (lower micronnaire) cotton types traded generally at a discount to the normal/premium micronnaire range cotton are also being used for the purpose of spinning counts suitable for denim applications. Pre-consumer waste fibres like combernoil, flat stripping(generally to the extent of 10-20%) are also used in mixing with fresh cotton for spinning medium to coarser yarns for denim.

The important and well-known cotton varieties suitable for spinning coarse count yarns are primarily desi or indigenous cotton strains like Bengal Deshi grown in the Northern Zone states of Punjab, Haryana, Rajasthan, V-797 (Kalyaan)in Gujarat, AK/Y-1 in MP and Maharashtra,Jayadhar in Karnataka and some other now lesser-known types in Tamil Nadu.With the advent of high yielding varieties, hybrids and Bt cotton, the production of indigenous short staple cotton types has been on the decline. The increasing denim capacities and smaller crop production sometimes necessitates imports of these cotton types.

The denim industry is also seeing lot of innovations as far as sustainability of fibres is concerned. Whereas, Organic and Better Cotton (BCI) are other sustainable alternatives to conventional cotton, other natural fibres like hemp, linen and silk are being looked upon as important alternatives to scarce and highly resource intensive cotton fibre. Various combinations of silk (mulberry and eri silk) are being tried with cotton and linen to produce versatile new range of fabrics. Whereas eri silk’s warmth like wool makes the denim garments suitable for cold weather, other blends of silk with cotton and linen have been found to be providing light weight and comfortable denim fabrics for all weather conditions. Biodegradable synthetics and bio elastomers are other important sustainable innovations at the fibre level.

Since denim is a warp-faced textile with weft passing under two or more warp threads, studies on clothing comfort in denim fabric from regenerated cellulosic fibres suggest that Indigo dyed cotton warp and viscose filament/Tencel weft offered greater degree of wearing comfort. Regenerated cellulosic fibres like viscose, Modal, ProModal, Tencel, blends of cupro, rayon and bamboo have evolved as important manmade sustainable fibre alternatives in denim manufacturing. Besides being eco-friendly, these regenerated cellulosic fibres and yarns provide much sought-after soft handle, lightness, subtlety, suppleness, fit, comfort, strength and durability to denim.

Recycling and embedding circularity in denim is adding a unique sustainability punch to this most popular attire.In addition to fresh sustainable fibres, recycled fibres (both cotton and polyester from pre-consumer and/or post-consumer wastes)are getting extensively used in denim manufacturing. Millsare setting up dedicated recycling unit (s) to recycle spinning, fabric and garment waste materials otherwise destined for the landfills.The post-consumer recycled cotton being slightly coarse and rough imparts an additional texture and dimension and richer color hues.

Fibres like Tencel Refibra lyocell as an important recycled fibre innovation is being seen as a step towards contributing to the circular economy in textiles. It involves upcycling cotton waste from garment production to make new lyocell fibre. Similarly, Re-Gen fabric is being made from half of recycled cotton and half of Refibra and not a single kilo of fresh cotton fibre is used.This is leading to conserving lot of resources like water, fertilizers and avoids polluting agro-chemicals in the form of pesticides and insecticides used to grow cotton.

Ring spinning remaining the main stay of yarn manufacturing for denim fabrics, experts foresee growth in open-end spinning with an increased use of recycled fibres. Ring and Open-end core spun, elastic ply yarns, multi-component and bi-component synthetic filament yarns are used to provide stretch. Slubs and multi-count yarns are being used to provide fancy effects to the denim fabric. Knitted denim, SolucellAir cotton yarns (combining Solucell and cotton to engineer 3D hollow channel system inside the cotton fabric), embedding conducting fibres and composite materials into denim, robotic cutting and sewing for higher quality garments, 3D-printed jeans are few other innovations which hold the potential to revolutionize the denim industry. Use of Artificial Intelligence (AI)and 3D visualization in the design process and to study trends and improve retail interface are also in vogue.

Nanotechnology is providing newer application techniques and imparting more durable and innovative functional finishes like UV, antimicrobial protection, stain-resistance, nano encapsulation amongst othersthereby offering higher realms of textile performance, comfort, and environmental friendlinessthan the conventional.

Graphene as the wonder material isolated from Graphite is being used as safe, chemical free and non-toxic functional finishto enhance the denim fabric through thermal distribution(when coated on the surface of the fabric), prevent formation of bacteria, an anti-odour effect and a very high abrasion resistance. Various value-added effects like vintage, streaks, fading, stone wash, peach skin, oily feel, permanent 3D creases and others are now achieved by the use of enzymes, special finishes and chemicals. Foam coatings, ozone and ammonia finishing, bonding, tinting, natural and totally biodegradable sizing and others are leading smart innovations which are helping the denim industry go green and conserve water and energy, reduce consumption of chemicals, manufacturing costs, lesser release of GHGs and enhance biodegradability. There is a new awakening and a quest to achieve product stewardship by meeting the cradle-to-cradle (C2C) design standards and certification and sustainability criteria of various eco-labels like Oeko-tex, green label, blue sign amongst others.

The denim industry is also striving hard to innovate in dyeing and processing technologies to remain sustainable. Various other dyeing techniques like the Crystal-Clear dyeing, Nitrogen dyeing, foaming, spray dyeing, Indigo Juice dyeing, patented Kitotex, pre-washing and creating of motifs through lasers are some of the innovations in dyeing and processing of denim which conserve precious resources like water, energy and chemicals unlike Indigo dyeing which is most water and chemical intensive with a high environmental impact.

The plethora of innovations at the level of fibres and their blends, yarn types, stretch fibre content, weaving techniques and fabric constructions are all contributing to making denim an even more desirable fabric ranking high on fashion and performance.

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World Textile Fibre Demand, ICAC, December 2021

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