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Topics - nawshin farzana

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16
Textile Dyeing / Recent Developments In Dyeing
« on: November 15, 2018, 04:02:41 PM »
Air Instead Of Water
Airflow was the key element of the technology, as air is an ideal transport medium. The replacement of dye liquor with air as a method of transporting piece goods in jet-dyeing machines was a big step toward reducing water and chemicals consumption. Compared to the jet system in which the nozzles are filled with liquor, nozzle pressure is negligible, thus offering optimum protection
of sensitive textile surfaces. At the same time, the use of the mass flow principle provides a major improvement in fabric hank laying, thus preventing creasing.
The moisture-saturated airflow ensures the uniform distribution of temperature on the fabric and in the machine, constituting a prerequisite for even and reproducible dyeing. Moreover, the low level of liquor in the dyeing boiler means the fabric is lighter than in conventional machinery and can therefore be accelerated quickly to high speeds. Thus, the risk of draft or strain is minimal,
which is particularly advantageous with regard to the finishing of items containing elastane fibers.

The Airflow technology represents the combined result of the entire range of possibilities
provided by the technology. Through the interplay of all technical possibilities and functions,
economic and ecological advantages over the traditional dyeing technology are achieved. The main
advantages are as follows:
-unlimited flexibility with regard to all fiber – except pure wool – and fabric weight classes
between 30 and 800 grams per square meter, as well as all standard market dyestuffs;
-the lowest liquor ratio on the market: approximately 1:2 for man-made fibers and 1:3 to 1:4 for
natural fibers, depending on the article and structure;
-energy savings of up to 40 percent, thanks to a frequency converter, and the use of air as a
transport medium, while all other systems need water;
-a reduction in the overall process time of approximately 25 percent; and
-lowest water/wastewater levels.

source: internet


17
Textile Engineering / Pineapple fabric- Pinatex
« on: April 28, 2018, 05:15:46 PM »

Although the idea may sound unbelievable, there is a vegan alternative to leather, which is made from pineapple leaves. London-based Ananas Anam has developed a natural and non-woven textile out of pineapple leaves, known as Piñatex which is remarkably similar to leather. The revolutionäre pineapple fabric is made from pineapple leaf fibres, a by-product from the pineapple harvest in the Philippines. During a process called decortication, the fibres are extracted from the leaves. The fibres then undergo an industrial process to become a nonwoven textile, which is the base of Piñatex. A by-product derived from the manufacturing process is biomass, which is converted into organic fertilizer or bio-gas and used by the farming communities, thereby closing the loop of the material's production.

Piñatex is the result of years of work and the search for an alternative to leather; a new type of natural tissue, which is 100 percent vegan and sustainable. In addition, it is also a strong, yet versatile, breathable, soft and flexible, material which can be easily printed on, stitched and cut, making it suitable for a number of fashion products. It has also won a number of awards. The next big step is to popularise Piñatex further and to continue developing and stabilizing its supply chain to meet the growing demand for its pineapple leaf, in a way that does not compromise its mission and fundamental values concerning environmental, ethical, social and economic sustainability.
source: internet

18
Textile Engineering / recent advances in textile technology
« on: April 28, 2018, 05:11:10 PM »
Color-Changing Fabrics

While parts of the fashion world obsess over an ever-changing parade of “This Season’s Hottest Color,” a small group of pioneers are perfecting the means to rewrite the spectrum entirely. A far cry from the gimmicky heat-sensitive Hypercolor T-shirts of the ’90s, modern advances in photochromatic technology are throwing up some intriguing possibilities for the way we dress, and how our clothes themselves react to our environment.

What’s most exciting about modern color-changing technology is that it’s progressing from a number of different directions, each one built on entirely different scientific principles. The first, currently being explored by scientists at the University of Michigan, involves a membrane of tiny crystals that react differently when exposed to various wavelengths of light. As the light shines on a wafer thin sheet of indium tin oxide, a charge is created that causes the crystals to change their formation, affecting the fabric’s color and outward appearance. The U.S. military has already expressed interest in using this technology to develop active camouflage (much like that of a chameleon), but scientists working on the project have given no reason why it couldn’t be adapted for the consumer marketplace as well.

Over at Concordia University in Montreal, however, there’s another approach being trialled altogether. As part of a project dubbed “Karma Chameleon,” scientists are investigating a way to harness electricity from the movement of the human body and use it to power a new kind of “electronic fabric.” Using a very subtle current, the material would trigger super-fine wires woven into its makeup to change its color or illuminate according to the wearer’s actions. Beyond that, the hope is to develop a fabric that can charge itself via the body and store energy independently, using it to completely change in appearance at the wearer’s discretion.

source: internet

19
Textile Engineering / Moisture management fabrics
« on: August 06, 2014, 03:35:01 PM »
Moisture management is one of the key performance criteria in modern sports and active outdoor wear is moisture management—the ability of a garment to transport moisture away from the skin to the garment’s outer surface.

The market is dominated by Invista’s portfolio of moisture management fabrics—which include CoolMax, Tactel Aquator, ThermaStat, Thermax, and Thermolite Base. However, the pace of development has accelerated over the past ten years, and a growing number of other companies have started to compete. Such companies include American Fibers and Yarn, Comfort Technologies, Hind, Honeywell, Intera, Intex, Lenzing, Marmot, Milliken, Mitsui, Nano-Tex, Nike, Patagonia, Pearl Izumi, Polartec, Reebok, Rhovyl, Schoeller, Tomen, USA-Pro, and Wellman.

For applications in which wicking is essential—such as base layer garments—the most commonly used material is polyester. This is often chemically modified to create a fabric in which the fibres encourage moisture to migrate through it. However, fabrics which are made from modified wool, cotton and polyamide (nylon) may provide similar or superior properties to polyester.

The number of moisture management fabrics on the market has increased dramatically in recent years. This trend is likely to continue over the next few years as manufactures strive to boost the comfort of their offerings.

As the number of fabrics and fibres with moisture management properties increases, so will the number of applications. In addition to sportswear and active wear, there is growing interest in the use of moisture management fabrics in the flame retardant apparel market.

The next generation of textiles is likely to incorporate nanotechnology, as it has already been proven that extremely fine fibre surfaces have beneficial properties. In addition, the near future could see the development of smart fabrics which are able to respond to changes in the environment by adjusting their pore size or thickness at a given moment to facilitate moisture transmission.

20

Even we add some amount of Ca n Mg ions in soft water to make it hard for enzymatic desizing-

 what actually hard water do with it r how it increases rate of reaction:
 
Salts and ions may have many different effects of the activity of an enzyme.For example, inorganic ions may bind to some of the ionic side chains of a protein. This kind of interaction, although not affecting the three dimensional shape of ...the enzyme in a substantial manner could make it easier for a substrate molecule to locate or bind to the active site of the enzyme. Thus the presence of the ion in optimum concentrations could alter the rate of the reaction.

Many enzymes exist in two states, an inactive and an active state.Usually these states differ in the conformation, or three-dimensional shape of the enzyme. The balance between these two states provides a means for regulating the activi...ty of the enzyme, in effect, by turning it on or off.

 Often the switch that controls which state the enzyme is in is provided by a small molecule which binds to a receptor site somewhere on the surface of the enzyme. Such a small molecule is called an allosteric effector. For alpha-amylases from mammals, chloride ion is the allosteric effector. These amylases have a binding site for chloride ion, which contains a positively charged amino acid residue (lysine, which at physiological pH is in the ammonium ion form). This positive charge assists binding of the negatively charged chloride ion, and the size of the binding pocket excludes larger negative ions.

Binding of chloride causes a conformational change to the amylase, switching it to the more active state. we use alpha amylase enzymes in desizing.

21
Textile Engineering / Restricted Substances in textiles
« on: July 22, 2014, 07:04:35 AM »
Azo/Carcinogenic/Allergenic Dyes
Azo dyes are synthetic dyes having an azo
group (-N=N-) in the structure. Azo dyes are
commonly used for dyeing textiles and leather.
Some azo dyes may produce carcinogenic
aromatic amines under certain conditions.
In Europe, REACH Regulation (EC) No
1907/2006, Annex XVII restricts 22
carcinogenic aromatic amines in textiles and
leather. Some other dyes used in the textile
industry are classified as having adverse
effects on humans. More than 20 dispersed
dyes are said to be allergenic, while 9 dyes
are classified as carcinogenic. These dyes
may be absorbed through the skin with
prolonged skin contact.
Formaldehyde
Formaldehyde acts as a cross-linking agent to
make an easy-care finish, intended to prevent
shrinkage, and gives the product
crease-resistant and smooth-dry properties.
Release of Formaldehyde can be harmful to
health through irritation of mucous membranes
and the respiratory tract.
Pentachlorophenol (PCP),
Tetrachlorophenol (TeCP) &
Trichlorophenol (TriCP)

To prevent mold spots caused by fungi,
chlorinated phenols like PCP are applied
directly on textiles, leather and wood. PCP is
very toxic and regarded as a
cancer-inducing agent.
Pesticides
Pesticides are used in the cultivation of
natural plant fibers like cotton to combat
insects, and also as a moth protection agent
during storage. Herbicides are
weed-eradication and defoliant chemicals.
They can be absorbed by the fibers and
might remain in the final product. Most of
them can be removed during subsequent
wet processing. Pesticides and herbicide
residues are rated slightly to strongly toxic
and are sometimes easily assimilated
through the skin.
Heavy Metals
Heavy metals are constituents of some dyes
and pigments. They can also be found in
natural fibers due to absorption by plants
through soil. Metals may also be introduced
into textiles through dyeing and finishing
processes.
Once absorbed by humans, heavy metals
tend to accumulate in internal organs such
as the liver or kidney. The effects on health
can be tremendous when high levels of
accumulation are reached. For example,
high levels of lead can seriously affect the
nervous system.
Heavy metals very often refer to:
 
Antimony (Sb)
 Arsenic (As)
 Lead (Pb)
 Cadmium (Cd)
 Mercury (Hg)
Copper (Cu)
Chromium (VI) (Cr(VI))
Total Chromium (Cr)
Cobalt (Co)
Nickel (Ni)

Both Cadmium and Lead are classified as
carcinogens. Cadmium has been restricted in
Europe for a long time. Lead is restricted in the
U.S. under the Consumer Product Safety
Improvement Act (CPSIA) in addition to certain
European regulations.
Chromium (VI)
Chromium (VI) is mainly an undesirable
by-product generated during the leather
tanning process when chrome tanning is
employed. Subsequent warehousing and
transportation may lead to higher levels of
Chromium (VI). Chromium (VI) is a strong
oxidant and is classified as a carcinogen that
needs to be controlled.
Nickel
Nickel is found in alloys used for metal
accessories on garments such as buttons,
zippers and rivets. Some people are allergic to
nickel and may experience serious skin
irritation when in contact with nickel-containing
accessories for an extended period. The
release of Nickel is restricted under the EU
REACH Regulation (EC) No 1907/2006, Annex
XVII.
Phthalates
Phthalates are the most popular plasticizers
used to soften Polyvinyl Chloride (PVC). Other
applications include Polyurethane (PU) and
printing inks. Some studies have shown that
under simulated mouthing conditions, softened
PVC might release phthalates in quantities
considered to cause potentially hazardous
effects in young children. Various countries
across the globe have restricted phthalate use
in childcare products through legislation such
as the U.S. Consumer Product Safety
Improvement Act (CPSIA) and the EU REACH
Regulation.
TBT, DBT and Other Organotin Compounds
In the textile industry, TBT has been used for
preventing the bacterial degradation of sweat
and the corresponding unpleasant odour of
socks, shoes and sport clothes. Some
organotins may be used in PVC and PU
productions. High concentrations of these
types of compounds are considered toxic.
They can be absorbed through the skin and
are suspected to cause reproductive disorders.
Chlorinated Organic Carriers
Commonly used as auxiliaries in the dyeing of
polyester, chlorinated organic compounds can
have adverse effects on the central nervous
system and may induce liver and kidney
malfunction.
Flame Retardants
Commonly used flame retardants are TRIS,
TEPA, Bis(2,3-dibiomopropyl) phosphate,
Polybrominated Biphenyls (PBB) and
Polybrominated Diphenylether (PBDE).
Prolonged contact to high dosages of flame
retardants can cause impairment of the
immune system, hypothyroidism, memory loss
and joint stiffness.
pH Value
Human skin is slightly acidic which inhibits the
development of many diseases. Textiles where
the pH lies in neutral (pH 7) or in slightly acidic
regions (below 7) are friendly to skin. Fabrics
with extreme pH values can easily damage
skin and may cause allergic reactions.
Dimethylfumarate (DMFU)
Dimethylfumarate is a volatile compound
classified as irritating and harmful for the skin,
eyes, mucous membranes and upper
respiratory tract through simple contact,
inhalation or ingestion. The substance is used
as a fungicide to prevent mold formation that
may deteriorate leather, furniture, footwear or
leather accessories during storage or
transport, and may be used in dessicant
sachets. Dimethylfumarate is banned under
the EU REACH Regulation (EC) No
1907/2006, Annex XII.
Alkylphenols (AP) & Alkylphenol
Ethoxylates (APEO)

Alkylphenols and alkylphenol ethoxylates are
commonly used as wetting agents in textile
processing. EU REACH Regulation (EC) No
1907/2006 restricts the discharge of
Nonylphenol (NP) and Nonylphenol
Ethoxylates (NPEO). NPEO’s have been used
as detergents, emulsifiers, wetting agents and
dispersing agents for many years. NP is the
intermediate to synthesize NPEO. NPEO and
NP are very toxic to aquatic life and
considered aquatic pollutants. They can
disrupt the hormone-regulating system of
aquatic animals and cause estrogenic effects.
Octylphenol (OP) and Octylphenol Ethoxylates
(OPEO) are the other AP and APEO’s
commonly concerned.
Perfluorooctane Sulfonates (PFOS)
PFOS are widely used to provide grease, oil
and water resistance to textiles, apparel,
carpets, leather and paper. The substance is
considered to be very bio-accumulative and
toxic.
Volatile Organic Compounds (VOC)
VOC refers to a group of volatile organic
solvents. The chemicals are often used in
paint and ink preparations, glues, cleaning
agents, shoe primers, etc. Due to their organic
nature, these chemicals tend to have strong
and distinct smells. Some VOCs, such as
benzene, are carcinogenic. Some are very
toxic, and strong irritants.

22
Textile Engineering / Leno Bags
« on: July 22, 2014, 06:43:41 AM »
Leno bags are used for packing fresh vegetables, fruits, potatoes, onions, etc. They are specially woven and designed to maintain freshness of the packed goods by allowing air inside the bags to prevent inner moisture that may spoil the goods. These are UV-stabilized and made according to the customers desired specification and colours. These are available in 5 kg. up to 20 kg. capacity, with or without tie string.

The need for proper handling and packaging of perishable items like onions and potatoes, ginger, tomatoes, carrots, coconuts, apples, and other vegetables and fruits has been addressed. This is being well appreciated not only by growers or consumers but also by the various merchandising associations, traders and authorities involved in marketing of agricultural produce.

PVN is among one of the first to start LENO Bags production.

Types of Leno Bags

» PP Leno Bags
» Tubular Leno Bags
» Raschel Bags
» Mono Bags
» Circular Bags
» Extruded Bags


Leno Bags, also use Leno Mesh Bags, can be widely used for packing of various Agricultural products such as : Onion, Garlic, Potato, Carrot, Ginger, Orange, Pineapple etc. It is also popularly known as mesh bags. Leno Bags being permeable allow the air to pass through the bag which help to keep the the product fresh. With their low weights and cost effective nature, they provide a superior packaging alternative to other materials. These leno mesh bags or mesh leno bags can be made with or without a drawstring. The drawstring is made of braided flat tape. We always focus on specific requirements of clients and offer quality products. Apart from this we offer timely delivery of these leno mesh bags with reasonable prices.

These plastic leno bags are available in various configurations that meet the specific requirements of clients in the best possible manner. There are various kind of mesh leno bags available for various products like:

Leno Bags for OnionLeno Bags for packing Onion:
Leno bags provide a superior packaging alternative to other materials. Due to their permeability they keep the products fresh.

These mesh leno bags are developed to the highest standards of quality and exhibit a high level of flexibility and efficiency and can carry loads of over fifty kilograms.

Leno Bags for packing Potato:
Leno bags keep products safe and fresh for long durations. They have excellent re-usability and washability characteristics.

These leno mesh bags are ideal for the packing of Potatoes because they can carry heavy weights. These are available in various attractive colors and products can be seen clearly from inside due to that you can check the quality of products easily.

Leno Bags for packing Vegetables:
Leno bag for packing vegetables can keep the vegetables fresh. These bags helps in significant saving in energy cost in cold storage systems. These bags have excellent re-usability and washability characteristics.

Leno Bags for packing Fruits:
Leno bags are developed to the highest standards of quality and exhibit a high level of flexibility and efficiency and can carry loads of over fifty kilograms. Moreover, it is also appreciated for its better visibility and optimum quality.

Our bags keep products safe and fresh for long durations and have excellent re-usability and washability characteristics. Further, these are available in a wide range of attractive colors.

Leno Bags for FlowersLeno Bags for packing Flowers:
Leno Bags being low weight reduce the packing cost. Our bags keep products safe and fresh for long durations and have excellent re-usability and washability characteristics. These bags are available in wide range of attractive colors.


Other Benefits for Using LENO Bags are:

Good tensile and burst strength
Lighter in weight than Corrugated Boxes hence transportation cost will be lower (Corrugated Box of similar capacity is 6 times heavier than leno bags)
Cheaper in comparison to jute bags
Reusable, however number of cycles depends upon the material packed, storage, handling and other relevant parameters.
Not attacked by fungus, insects and rats
Resistant to corrosive chemicals
Safe in direct contact with food products and do not cause physical contamination.
Easy visual inspection of contents packed is possible in leno bags.

23
Textile Engineering / Bio stone wash finish of Denim
« on: July 22, 2014, 06:28:46 AM »
Stonewashing added a new dimension to denim garments in the late 1970s: the process enabled artificial ageing of denim garments which imparted a fashionably aged look. As the name 'stonewashing' implies, the blue jeans were washed with pumice stones to achieve a faded look.

Due to the disadvantages of using pumice stones, such as-

Machine damage
blocking of the drainage system
difficulty in removing pumice-stone residues
excessive damage to garment hems and seams
large amount of stone required for small batch


So the alternative methods for stonewashing were developed. Cellulose enzymes were introduced in the 1980s as a denim-washing, aid to achieve a faded and abraded look similar to that provided by pumice stones. Cellulose works by loosening the indigo dye on the denim in a process know as 'biostonewashing'. A small dose of enzyme can replace several kilograms of pumice stones.

Biostonewashing has opened up new possibilities in denim finishing by increasing the variety of finishes available. For example, it is now possible to fade denim to a greater degree without running the risk of damaging the garment. Productivity can also be increased because laundry machines contain fewer stones or no stones and more garments. The use of less pumice stone results in less damage to garment and machine, and less pumice dust in the laundry environment.

A range of celluloses for denim finishing, each with its own unique properties, is available in the market. These can be used either alone or in combination with pumice stones in order to obtain a specific look. An ideal biostone wash enzyme would possess high abrasive activity (the ability to remove indigo from denim) as well as low back staining with lower fabric strength loss.

Celluloses have been used for the past twenty years and it is estimated that approximately 80% of denim garments are processed in this way. Celluloses are enzymes that are specific for the hydrolysis of the beta-1, 4 glucose linkage of cellulose. The reaction mechanism of the naturally occurring cellulose enzymes on cellulose is very complicated and several different enzymes endoglucanases, cellobiohydrolases and beta-glucosidases are synergistically involved in the chain of reactions needed to break down cellulose into glucose. The first type of celluloses introduced to market was derived from the Trichoderma family, a fungus with the longest history of cellulose research. The second phase in the, development of cellulose was the introduction of products based on another fungus called Humicola insolens. These celluloses soon became known as the neutral celluloses, as they could work in a more neutral pH environment. A special feature of the neutral celluloses is their ability to provide the stonewashed look with minimal indigo redeposition during the treatment. Thus the jeans and other denim garments would have a higher contrast between white and blue yarns, and the inside pockets as well as the leather labels would not be stained with indigo. However, the reaction time of this enzyme is slow and its use requires a longer processing time.

Since then, much progress has been made in the development of cellulose compositions, which are customized to achieve specific applications. Research and development activities have been focused on a new generation of cellulose enzymes whose composition has been altered through genetic engineering to provide higher abrasion contrast, reduced back staining, improved fabric-strength retention and broadened operating pH and temperature ranges. The development of modern biotechnology brought new tools for scientists to create new, better cellulose products for textile applications.

Benefits:
Valumax A 376 is a high-per formation. Ready-to-use cellulose for the abrasion of denim (stone washing) .this produce allows new shades and finishing to be created and cost-effectively in an environmentally friendly way.
 
High color contrast finish
Low degree of indigo back staining
Optimum strength retention
High degree of reproducibility and reliability
Maximized fabric strength retention
Improved wash look or creation of new looks
Easy handling
Cost effectiveness

24
   
The most popular use of para-aramid fibres is the ballistic protection in Western Europe, truck and bike tires, tension reinforcement for fibre optic above ground cables and protective coverings for underground and underwater fiber optic cable, but it is being predicted that the research and development in this stream of aramid fibres is likely to ensure that the para-aramid fibres are used to some more important uses.

Para-aramid fibres are imported on a large scale by developed countries. In such a scenario, it is a surprise that the growth of para-aramid fibres has not yet reached its full potential. Even though there is a gleam of hope as the production in Western Europe and Japan has risen greatly in the last decade, but this production is confined to a single company. This company accounts for about one-third of the total production in Europe and about one-half of the production in Japan. The trend of newer entrants in production of para-aramid fibres is also not very encouraging.

25
Textile Engineering / Bamboo fiber
« on: July 22, 2014, 06:15:44 AM »
Bamboo fiber is one of the new generation cellulosic fibers which are extracted from bamboo plants. It can be bast fiber or regenerated fibers based on its process of extraction. Bamboo fibers are getting very popular these days because of its unique properties in term of feel, comfort, natural shine, and its anti UV and antibacterial properties.

Botanically bamboo is a variety of grass. It belongs to the subfamily Bambusoideae of the family Poaceae. It is one of the fastest growing plants. Bamboos are found in tropical, sub-tropical or temperate zones which mainly consist of South Asia, south East Asia, South America and south east portion of the United States. The main country producing bamboo fibers is China. Mostly Phyllostachys pubescens and similar species are used to produce bamboo fibers. Phyllostachys pubescens is known as Moso bamboo in China.

Major content of bamboo fiber is cellulose. The cellulose content increases from raw bamboo to fiber during fiber production process. 90% of the dry weight of the fiber comprises of cellulose, hemicellulose and lignin.

26
Textile Engineering / Bio-mass fibres in textiles
« on: July 22, 2014, 06:14:29 AM »
Biomass fibers are obtained from renewable biomass resources such as natural animal and plant fibers, recycled fibers and synthetic fibers. As resources of textile raw materials are diminishing, developing biomass fibres will prove to be an important step in expanding the market of sustainable textiles. Also, using biomass fibres will be an effective method in establishing sustainable fibres in the textile industry.

Natural fibres are produced in all the countries of the world. Various products like textiles, ropes, brushes, carpets, mattresses, mats, paper, board materials, etc. are manufactured from it. The development of renewable, biodegradable biomass fiber also promotes the growth of the chemical fiber industry. Currently in China, the biomass fiber industry has developed considerably. It produces over 200 million tons of biomass fibres. With such large biomass fiber resources, it paves way to significant development of this industry.

27
Textile Engineering / Tobacco Dyes
« on: July 22, 2014, 06:07:34 AM »
A newly manufactured dye is all set to revolutionize the textile industry, and also change the views about a plant which usually has only negative connotations.

In the process of making tobacco for cigarettes' only the leaves are used. The remaining tobacco plant is normally discarded as waste. A new ground breaking technology uses tobacco plant as a renewable resource. Dyes extracted from the plant fibre are being used for creating hues on textiles which are not just cost effective but are also non-toxic.

Plant fibres have been used for making textiles from which a wide range of fabrics are manufactured. Various plants such as hemp, jute, ramie etc are used for extracting fibres and making textile. One plant which was not utilized in this way is the tobacco plant which belongs to the genus Nicotiana. Many species of tobacco plants fall within the category of genus Nicotiana which is generally referred to as tobacco plants. Tobacco plants are mainly grown for its leaves. Their leaves are used for smoking, snuff, and chewing. They are also used as organic pesticides and also in some medicines.

Fibres extracted from the tobacco plant are used for making dyes. A hot liquid solution is used on the tobacco plant causing a chemical reaction to produce the tobacco plant fibre. The equipment used for extracting this dye requires less water than the other conventional dyes. Percolating the hot solution on the tobacco plant produces steam, which is directed back to the treating system. The liquid that is collected inside the treating system, and the pulp produced inside the treating system is utilized as a natural dye for textiles.

It also does not require purifications of toxic water as is by the conventional dyeing processes. Tobacco plants are used in the application process which minimizes waste reduction. The process of dye extraction successfully provides around 30 vibrant shades.

Apart from extracting dyes from the plant, fibres extracted from the tobacco plant can also be blended with other fibres such as wool, silk, cotton, etc. Fibres extracted from the tobacco plant are used for making coverings, clothing, bags, and many more applications. The fibre can also be blended with other natural fibres such as plant fibres, animal fur or even synthetic, derived from petroleum.


28
Textile Engineering / Herbal Dyeing - A Step Ahead to Organic Life
« on: July 22, 2014, 06:03:22 AM »
Herbal Dyeing

Herbal dyeing or technically, natural extract impregnation into textiles is a part of 5000 years old system of Vedic health care which supports the core concept of Ayurvastra natural healing provided by clothing. These fabrics are infused in ayurvedic medicinal solution (kashayam) and its properties are permanently encapsulated to the fabrics having various health benefits. Herbal textiles are a perfect amalgamation of cloth and wellness; this unique fabric incorporates in itself the rich Indian culture with health benefits.

India is known from time immemorial for natural dyeing expertise. Natural dyes are known for their soft, lustrous colors and endurance. It also retains great beauty and charm for long term. In herbal textile all kinds of hues of reds, yellows, browns, orange and greens can be made from stem, wood, leaves, fruit, seeds etc .

Dyeing Process

After bleaching organic cotton in natural solutions like cow urine etc, dried in sunlight. Before dipping into natural concoction of plant extracts, a natural gum is applied on the fabric. The fabric is left to dry for 3 days and then kept in a room for a definite period of time that allows the fabric to dry completely and the extracts to settle in to the fabric. It is then washed, dried in the shade, and seasoned further.

Wellness Textiles

As Ayurveda suggests various ways of disease treatments like steam bath, massage, oleation, sweating, heating and so on for various ailments with different herbal concoctions, as the basic principle is that the extracts have to be in contact with the skin. In our present busy world, these potential methods are not much explored mainly due to the time limitations and stringent practices. This lead to the rise of new branch of technical textile called Wellness textiles.

As per the experts, by coming contact with herbal cloth, body loses toxins and the metabolism enhance like in case of microencapsulation technique. As skin functions as the protective barrier but also as a conduit for outside substances to enter the body, same way skin also absorb medicinal molecules from textiles and result in improved resistance against harmful substances.

Sandalwood: It retains its fragrance for decades and provides cooling effect. It retains its fragrance for decades and provides cooling effect.
Neem:This herbal dye would help to fight against various skin diseases.
Neela Amari or Indigo: This herbal dye this would help fight skin disease.
Ramacham or Cuscus Grass: If garment is dyed in this dye this would help fight asthma disease.
Turmeric/Tulsi: Used for garments having sleep enhancing benefits etc.

29
Textile Engineering / Waterless Dyeing Techniques
« on: July 22, 2014, 05:57:16 AM »
The textile industry has been one of the largest consumers of water and is also responsible for polluting the environment with chemical treated waste. It is estimated that on an average to process one kilogram of textile material, 100-150 litres of water is required. Many companies are working towards cutting back on the usage of water by conserving, recycling, dye sublimation, and other new technologies.

Water is the key component and is used as a solvent in pre-treatment and finishing processes such as washing, bleaching, dyeing, rinsing, and scouring. According to the World Bank, textile dyeing and treatment are the source of 17-20% of industrial water pollution. Until a few years back, there was no substitute for dyeing fabrics but by using water. Thanks to dry dyeing, a waterless dyeing technique, this is possible now. This process makes use of carbon dioxide to dye textile materials. A super critical liquefied form of carbon dioxide dyes fabrics, providing same results as the conventional water based methods.

The dry dyeing method, a pioneering work of a Dutch company in textile dyeing, does not make use of water at all. Super critical is a state where matter can be expanded into a liquid or heavily pressurized and converted to gas. When carbon dioxide is heated to over 31°C and pressurized to above 74 bar, the super critical state is then achieved. Carbon dioxide's liquid like densities proves to be beneficial for dissolving hydrophobic dyes and the gas like densities, have low viscosities and diffusion properties.

The supercritical carbon dioxide technique is already being used in apparel dry cleaning, and has proved to be by far the best, most gentle, and the cleanest method to do so. There are various reasons as to why carbon dioxide is the best supercritical fluid for the dry-dyeing technique. It is a naturally occurring inexhaustible resource, physiologically compatible, and relatively inexpensive.

Carbon dioxide is readily available, is biodegradable, and does not release any form of volatile organic compounds. Moreover, it is non-toxic, non-flammable, and non-corrosive. These merits make it a very viable dyeing alternative. The biggest merit of using carbon dioxide is that it can be recovered, and reused again from the process of dyeing, making it a cost-effective option.

This method of waterless dyeing is also used for printing on garments. The water-based dyeing techniques involve drying the garment, once it has been colored, while this new innovative technique eliminates this process altogether.

Currently, the supercritical carbon dioxide is limited to dyeing of synthetic and polyester fabrics with modified dispersed dyes. However, efforts are being made by the company and innovators to develop dyeing methods for cellulosics in the distant future. Carbon dioxide makes the polymer swell letting the disperse dyes to easily diffuse within the polymer, penetrating the pore and capillaries of the fibres. Circulation of the dye solutions using the aqua free dyeing method is easier and consumes less energy. The deep penetration leads to effective coloring of polymers. The residue produced is minimal and can be recycled.

Dyeing with carbon dioxide delivers brilliant results in terms of dye levelness and shade development. The physical properties are also as good as the conventional dyeing methods. This kind of dyeing is done in equipments, where in the fabric is rolled and inserted in a high pressure vessel filled with carbon dioxide, and pressurized up to 250 bar. Removing excess dye is also done in the same vessel. The viscosity of dyes produced by this process is low. Water less dyeing when compared to conventional dyeing forms consumes very less energy, disposes less waste, and completes the dyeing process in approximately two to three hours. This makes it an environment friendly and sustainable alternative.

Similarly, a Switzerland based denim dyeing company created a new eco-friendly dye that uses 92% less water, 30% less energy, and saves up to 63% cotton waste and produces same coloring results when compared to conventional techniques. This state of the art process hands over improved color fastness, better production of tones, and helps achieve deeper blues.

Brands like Adidas and Nike have already considered these methods for dyeing clothes to meet the demands of consumers who are environment conscious. Since athletic and sportswear use polyester and single color, this process would be just perfect.

Ingenious technologies like these in fabric dyeing can bring a positive change in the dyeing processes of the textile industries. Such inventions will bring the textile and apparel companies and the users a step closer towards making the environment cleaner and greener. Needless to say, it will also solve the problem of water scarcity and value the ecological resources.

Efforts like these must be endorsed, applauded, and recognized to pave way for sustainability and curb pollution caused by various industrial textile activities.

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Fluorescent brightening agents (FBA) sometimes called optical brightening agent (OBA) or fluorescent whitening agents are fluorescent white dyes that absorb ultraviolet region (340 370 nm), light of electromagnetic region emit back visible blue light region (420 470 nm). Its suitable for cellulose, nylon, polyester, silk, wool, paper and other polymers. Optical Brightening Agents are 'colourless dyes' which are capable of absorbing invisible ultra violet light and remitting visible 'blue' light

Texlile fibres, detergents, printing paste, polymer, paper, plastics and coatings in the raw state possess aesthetically undesirable creamish cast. The reason of this in case of natural materials is the presence of the natural dyes and pigments and in the case of man-made fibers this is attributable to thermal decomposition. The coloring matter, whether it is natural or present as a contaminant in the fiber is generally decolorized by different bleaching methods. But still they retain a faint, creamy colour. Excessive bleaching can degrade the substrate extremely. Tinting with bluing agents or optical brightening agents can compensate this residual yellowness. Materials treated with these agents appear less yellow. Therefore chemical treatments are become necessary to neutralize the yellow tint of the textile fibers. Optical brightening agents are also used in polymer and cosmetic industries.

Virtually all white fabrics have OBA incorporated or applied during processing. Commercial laundry detergents contain OBA(s) to 'top-up', maintain or increase the level of OBA on the fabric.

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