Textile Industry is offering one of the most basic requirements of the community and it possess importance; preserve continued growth for developing quality of life. From the manufacturing of raw materials to the delivery of end products, it has gained its kind of position, as a self-dependent sector and with considerable value addition at every stage of dealing; it is a key input to the country's economy.
The technological advances of textiles in various industries do not always get recognized as they do in the clothing industry. Textile products play a vital role in meeting man's basic needs. We often only consider textiles to be the clothes we wear. Obviously, the clothing industry is where the majority of textiles are produced and used. However, textiles are also important in all aspects of our lives from birth to death. Textile Industry is offering one of the most basic requirements of the community and it possess importance; preserve continued growth for developing quality of life. The use of textiles has been traced back over 8500 years. Textile Industry is offering one of the most basic requirements of the community and it possess importance; preserve continued growth for developing quality of life. From the manufacturing of raw materials to the delivery of end products, it has gained its kind of position, as a self-dependent sector and with considerable value-addition at every stage of dealing; it is a key input to the country's economy. The technological advances of textiles in various industries do not always get recognized as they do in the clothing industry.
The diversification of a country's industry is an important element for a stable and sound economy to absorb a proportion of the growing labor force. The more diversified a country's industry is, the better the opportunities to recover from chocks in the form of competition, price falls due to excess supply, etc. In a combined analysis of the market potential and human development impacts of various sectors, three sectors that meet these criteria are identified: tourism, handicrafts and food processing. The handicraft sector is a pro-poor industry that creates a high level of employment and generates income for local people, particularly those in rural areas. The Indian textile and clothing industry has comparative advantage in production and exports which could not be fully utilized because of quantitative restrictions imposed by her major export markets such as USA and European Union.
Textiles consist of fibers, yarns, fabrics and finishes. Each of these stages has a variety of processes involved to reach the next stage. Hand and feet have even today remained the tools for various processes supported by materials like wood, terracotta, metal, yarns, beads, semiprecious stones, colors etc. The concept of the Indian textile technologies is intricately related to both, the manufacture and decoration. This may therefore be researched in a chronological framework starting from archaeological past to - the contemporary times. Regional developments have been very typical to certain styles of manufacture and decorations in textiles.
Driving Forces for Value Addition
* Consumer
delight
* Value
added finishes
* Availability
of newer molecules
* Niche
markets
* Expanded
textile applications
* Retail
boom
Functional Finishes
* Encapsulated finishes
* Smart
textiles
* Anti
Static
* Moisture
management
* Odour
free
* Non
Ironing
* Anti
microbial
* UV
absorbers
* Cool
finish & Water proof finish etc
Miscellaneous Textile Products
* Toothbrushes
* Hair Brushes
* Dental Floss
* Artificial Flowers/Plants
* Book Bindings
* Candle Wicks
* Communication Lines
* Circuit Boards
* Commercial
& Eco Friendly Value Added Finishes
Commercial & Eco Friendly Value Added Finishes
The challenges facing the finishing industry have intensified in the last one decade, with finishers faced with the new task of striving to survive in this global and highly competitive market. Consumers demand more durability, more functionality from their clothing. Today's consumers insist on odour control, freshness, high performance and comfort. Apparel makers and the finishing industry are thus faced with a daunting job of producing superior fabrics that are technically advanced.
Phase Changing Materials for Thermoregulation
Every material absorbs heat during a heating process while its temperature is rising constantly. The heat stored in the material is released into the environment through a reverse cooling process. During the cooling process, the material temperature decreases continuously. A normal textile material absorbs about one kilo joule per kilogram of heat while its temperature rises by one degree Celsius. Comparing the heat absorption during the melting process of a phase change material (PCM) with those in a normal heating process, a much higher amount of heat is absorbed if a PCM melts. A paraffin-PCM, for example, absorbs approximately 200 kilojoules per kilogram of heat if it undergoes a melting process. In order for a textile to absorb the same amount of heat its temperature would need to be raised by 200 K. The high amount of heat absorbed by the paraffin in the melting process is released into the surrounding area in a cooling process starting at the PCM's crystallisation temperature. After com paring the heat storage capacities of textiles and PCM, it is obvious that by applying paraffin-PCM to textiles their heat storage capacities can be substantially enhanced. During the complete melting process, the temperature of the PCM as well as its surrounding area remains constant.
The undesired temperature increase concomitant with the normal heating process does not occur. The same is true for the crystallisation process. During the entire crystallisation process the temperature of the PCM does not change either. The high heat transfer during the melting process as well as the crystallisation process without temperature change makes PCM an area of interest for the heat storage. In their application in textiles, the paraffins are either in solid or liquid state. In order to prevent the paraffin's dissolution while in the liquid state, it is enclosed into small plastic spheres with diameters of only a few micrometers. These microscopic spheres containing PCM are called PCMmicrocapsules. The microencapsulated paraffin is either permanently locked in acrylic fibres and in polyurethane foams or coated onto the surface of a textile structure.
Easy Care Concepts
New concepts based on nanotechnology such as ease release, quick wick, rare care, finishes further improve the functionally of the textile by imparting the various properties such as Soil release, anti-pilling effect, water/oil repellency, hygiene effect, easy care and odor free effect. Other innovations based on 3-E concept offering 3 immediate benefits of Efficiency, Ecology and Economy include Black Magic - "No Rinse" process for discontinuous bleaching, exhibits less water, time and energy consumption.
Range of innovative effects, which:
* Reduce
the amount of energy required in the care of garments
* Keep
clothes fresher without washing
* Keep
garments looking new for longer
* Reduce
or eliminate the need to tumble dry or iron
* Eliminate
the need to dry clean
* Hence,
textile manufacturers may switch to such type of processes that may
typically
* Reduce
the finishes employed to the garments.
Shape Memory Materials
There are two types of Shape memory materials. The first classes are materials stable at two or more temperature states. In these different temperature states, they have the potential to assume different shapes, when their transformation temperatures have been reached. This technology has been pioneered by the UK Defence Clothing and Textiles Agency. The other types of shape memory materials are the electroactive polymers which can change shape in response to electrical stimuli. In the last decade there have been significant developments in electroactive polymers (EAPs) to produce substantial change in size or shape and force generation for actuation mechanisms in a wide range of applications. In contrast to many conventional actuation systems, many types of EAPs are also capable of providing sensing functions. EAPs can provide a range of basic actuator mechanisms, force and displacement levels.
Chronic Materials
Other types of intelligent textiles are those which change their colour reversibly according to external environmental conditions, for this reason they are also called chameleon fibres. Chromic materials are the general term referring to materials which radiate the colour, erase the colour or just change it because its induction caused by the external stimulus, as "chromic" is a suffix that means colour. Therefore we can classify chromic materials depending on the stimulus affecting as.
Photo chromic: external stimulus is light.
Thermo chromic: external stimulus is heat.
Electro chromic: external stimulus is electricity.
Piezoro chromic: external stimulus is pressure.
Solvate chromic: external stimulus is liquid or gas.
Photo chromic materials are generally reversible unstable organic molecules that change of molecular configuration with the influence of a special radiation. The molecular arrangement also perturbs the absorption spectra of the molecule and in consequences it colour. The applications in textile are intended to the fashion area and only a few for the solar protection. A T- Shirt made of photochromic prompted fabric was introduced to the market in 1989.
Thermo chromic materials are those whose colour changes as a result of reaction to heat, especially through the application of thermochromic dyes whose colours change at particular temperatures. Two types of thermochromic systems that have been used successfully in textiles are: the liquid crystal type and the molecular rearrangement type. In both cases, the dyes are entrapped in microcapsules and applied to garment fabric like a pigment in a resin binder. The most important types of liquid crystal for thermochromic systems are the so-called cholesteric types, where adjacent molecules are arranged so that they form helices.
Thermochromism results from the selective reflection of light by the liquid crystal. The wavelength of the light reflected is governed by the refractive index of the liquid crystal and by the pitch of the helical arrangement of its molecules. Since the length of the pitch varies with temperature, the wavelength of the reflected light is also altered, and colour changes result. An alternative means of inducing thermochromism is by means of a rearrangement of the molecular structure of a dye, as a result of a change in temperature.
The most common types of dye which exhibit thermochromism through molecular rearrangement are the spirolactones, although other types have also been identified. A colourless dye precursor and a colour developer are both dissolved in an organic solvent. The solution is then microencapsulated and is solid at lower temperatures. Upon heating, the system becomes coloured or loses colour at the melting point of the mixture. The reverse change occurs at this temperature if the mixture is then cooled.
However, although thermochromism through molecular rearrangement in dyes has aroused a degree of commercial interest, the overall mechanism underlying the changes in colour is far from clear-cut and is still very much open to speculation. Toray Industries reported in 1987 the development of a temperature sensitive fabric by introducing microcapsules, diameter 3-4 mm to enclose heat sensitive dyes, which are resin coated homogeneously over fabric surface. The microcapsule was made of glass and contained the dyestuff, the chromophore agent (electron acceptor) and colour- neutralizer (alcohol etc.) which reacted and exhibited colour/decolour according to the environmental temperature. SWAY was multicolour fabric, with basic 4 colours and combined 64 colours. SWAY can reversibly change colour at temperature greater than 5°C and is operable from - 40 to 80°C. The change of colour with temperature of these fabrics is designed to match the application, e.g. for ski-wear 11-19°C, women's clothing 13�22°C and temperature shades 24-32°C. Other types of SFIT that use this effect are the electrically warming textiles (with Joules effect) which change colour with both the effect of warm and thermochromic materials.
UV Protection
Fabric treated with UV absorbers ensures that the clothes deflect the harmful ultraviolet rays of the sun, reducing a person's UVR exposure and protecting the skin from potential damage. The extent of skin protection required by different types of human skin depends on UV radiation intensity and geographical location, time of day, and season. This protection is expressed as SPF (Sun Protection Factor), higher the SPF value better is the protection against UV radiation. The SPF value of textile depends on fibre type, the fabric construction (porosity and thickness), and the finish. It means that transmission, absorption and reflectance nature of textile influences SPF value. It provides vital information about the fabric's sun protection ability. By using UV absorbers, exposure of the textile to UV lights is reduced on the one hand as well as the intensity of the, transmitted UV light on the other. Good skin protection is achieved by the textile itself with a sufficient weight of fabric. An UV absorber can be applied either during fibre manufacture or in the final finish which also offers the same degree of protection.
Sand Blasting
Sand blasting technique is based on blasting an abrasive material in granular, powdered or other form through a nozzle at very high speed and pressure onto specific areas of the garment surface to be treated to give the desired distressed/ abraded/used look.
Stone Wash Effect
In traditional washing process, volcanic rocks or pumice stones are added to the garments during washing as abradant. Due to ring dyeing and heavy abrasion fading is more apparent but less uniform. The degree of colour fading depends on the garment to stone ratio, washing time, size of stones, material to liquor ratio and load of garments. Normally after desizing, stone wash process starts with pumice stone addition in rotary drum type garment washer. Process time varies from 60-120 mins. Stone wash effect is one of the oldest but highly demanded washing effects. Stone wash process gives "used" look or "vintage" on the garments, because of varying degree of abrasion in the area such as waistband, pocket, seam and body.
Wrinkle Free Treatment
By applying resins it is possible to improve specific properties of cellulosic fibres. Examples of this kind are the improvement in crease recovery, dimensional stability, non-iron, reduced pilling and particularly with knit goods an improved appearance after several washes. For successful resin finishing, it is absolutely essential that the goods are well prepared and the recipes and processes are adhered to and monitored exactly. The wrinkle free treatment package comprises of a low formaldehyde resin, silicones and polyethylene emulsion.
This treatment involves chemical application of the elements comprising of this package through a cross linking effect that prevents the formation of creases and wrinkles which result in easy to iron fabric. Resins do however also have several effects on the fibres. Resins reduce the (tear) strength of cotton. The extent of the loss depends on a wide variety of factors such as
* Amount
and type of resin applied;
* Amount
and type of catalyst;
* Curing
conditions;
* Quality
of cotton;
* Processes
preceding finishing
Tensile strength losses up to 30-45% could be expected. For the so called non-iron finishes, it is therefore often necessary to use qualities with a higher initial strength than for normal softening finishes. In this connection, it should be mentioned that the tensile strengths is not normally improved by the additives and softeners used.
Bio-Polishing
To produce this effect cellulose enzymes were introduced. Earlier Acid cellulose was used. To achieve this, Genetically Modified enzymes were produced, called GMO's (Genetically Modified Organisms). The bio-polishing process targets the removal of the small fiber ends protruding from the yarn surface and thereby reduces the hairiness or fuzz of the fabrics. The hydrolysis action of the enzyme weakens the protruding fibers to the extent that a small physical abrasion force is sufficient to break and remove them. Bio polishing can be accomplished at any time during wet processing but is most convenient performed after bleaching.
It can be done in both continuous or batch processes. However, continuous processes require some incubation time for enzymatic degradation to take place. Removing the fuzz makes the color brighter, the fabric texture more obvious, and reduces pilling. Unfortunately, the treatment also reduces the fabric strength. Smoother yarns also increase the fabric softness, appearance and feel. Since it is an additional process, the bio-polished garments may cost slightly more. Next time you buy apparel, look for the label "Bio-Polished."
Water/Oil Repellant Finish
When
finishing with these products, the surface of the goods must be covered with
molecules in such a way that their hydrophobic radicals are ideally positioned
as parallel as possible facing outwards. Aluminium salt paraffin dispersions
are positively charged products due to the trivalent aluminium salt. This
produces a counter polar charge on the fibre surface which is significant for
the adsorption of the product. This finish gives hydrophobic features to the
substrate. There are three main product groups for this finish
* Metal
salt paraffin dispersion
* Polysiloxane
* Fluorocarbon
polymers
After drying, the fat radicals form a so-called "brush" perpendicular to the fibre surface which prevents water drops from penetrating into the fibre. Polysiloxanes form a fibre-encircling silicone film with methyl group's perpendicular to the surface. The oxygen atoms are facing towards the fibre. The film formation and direction of the methyl groups are responsible for the hydrophobic properties of the finish.
Fluorocarbon polymers also form a film where the fluorocarbon radicals are perpendicular to the fibre axis thus prevent wetting of the fibre surface. Their high hydrophobic and oleophobic action is explained by the extremely low interfacial tension of the fluorocarbon chain towards all chemical compounds. When finishing with these products, the surface of the goods must be covered with molecules in such a way that their hydrophobic radicals are ideally parallel and facing outwards.
Anti-Microbial Finish
The inherent properties of textile fibres provide room for the growth of microorganisms.
The structure and chemical process may induce the growth, but it is the humid and warm environment that aggravates the problem further. Antimicrobial finish is applied to textile materials with a view to protect the wearer and textile substrate itself. Antimicrobial finish provides the various benefits of controlling the infestation by microbes protect textiles from staining, discoloration, and quality deterioration and prevents the odor formation. Anti microbial agents can be applied to the textile substrates by exhaust, pad-dry-cure, coating, spray and foam techniques. The application of the finish is now extended to textiles used for outdoor, healthcare sector, sports and leisure.
Enzyme Wash
Cellulase enzymes are natural proteins which are used i denim garment processing to get stone wash look on to t denim garments without using stones or by reducing the use of pumice stone. Cellulase attacks primarily on the surf of the cellulose fibre, leaving the interior of the fibre as it is by removing the indigo present in the surface layer of fibre Cellulase enzyme is classified into two classes:
Acid Cellulase: It works best in the pH range of 4.5-5.5 and exhibit optimum activity at 50.
Neutral cellulase: It works best at pH 6 however its activity is not adversely affected in the range of ph 6-8 and show maximum activity at 55 C.
Possibility factors for 55 C.
* Low
labor cost
* Low
cost of raw materia
* Huge
Product Selection
* Rising
domestic textile market
* Bulky
exports
* Government
concentration
Conclusion
In order to add value in the garments, different types of finishes are adopted. The application of Nano finishes has also been growing to obtain better level of performanceproperties. Ecology and Fashion are also the driving factors for the adoption of these innovative technologies. This will result in more greener and eco friendly textile industries and products. Textiles could be one of the most un-sustainable products in the world. In their entire lifecycle from growing the raw material or creating it from oil to manufacturing and selling and final disposal they can create a serious problem.
There are benefits at different life-cycle stages of the organic and eco-friendly fabrics trade, both for consumers and producers however, in the larger scale of things it is important to see that Eco friendly textiles and clothing may travel half way around the world to reach the ethical customer. As the demand of such Eco friendly Garments is increasing there exists a great scope for new entrepreneur to enter into this field. Textile industries are now able to provide one-stop sustainable solution along the whole textile value chain from pretreatment, through dyeing to finishing. The whole apparel supply chain can add value by adopting the eco-friendly finishes.
Originally Published in Textile Review, August-2011
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