Messages

46

Textile Engineering / Textile fibre in tumour & cancer cell surgery

« on: July 18, 2014, 10:24:39 PM »

Endovascular embolization is a medical procedure to treat abnormal blood vessels in the brain and other parts of the body. It is an alternative to open surgery.
This procedure cuts off the blood supply to a certain part of the body.

Particles of PVA (poly vinyl alcohol) are injected slowly with X-ray guidance to prohibit the supply of nutrition to some kind of cell, such as- a cancer cell , tumour, fibroid etc.
The iodinated PVA fibrils can be used as an embolic fiber for biomedical applications, owing to their-
high fineness,
good biocompatibility, and
good binding property.


Disadvantage of conventional metallic coil-shaped embolic materials-
Expensive
Problems during operation because of the sharpness of their cut faces

Advantages of PVA microfibril-
More effective
Comparatively superior properties
Less expensive
enhanced biocompatibility
less risk of scratching

Radiopacity is a very important characteristic for embolic materials for the minute positioning control of materials in human organs.
It is necessary to endow radiopacity to PVA fibrils by iodination to be used as embolic material.

47

Textile Engineering / Antimicrobial finish in textiles

« on: July 18, 2014, 07:03:17 AM »

The consumers are now increasingly aware of the hygienic life style and there is a necessity and expectation for a wide range of textile products finished with antimicrobial properties.
The inherent properties of the textile fibres provide room for the growth of micro organisms. Besides, the structure of the substrates and the chemical processes may induce the growth of microbes. Humid and warm environment still aggravate the problem. Infestation by microbes cause cross infection by pathogens and development odour where the fabric is worn next to skin. In addition, the staining and loss of the performance properties of textile substrates are the results of microbial attack. Basically, with a view to protect the wearer and the textile substrate itself antimicrobial finish is applied to textile materials.

What are microbes?
Microbes are the tiniest creatures not seen by the naked eye. They include a variety of micro organisms like bacteria, fungi, algae and viruses. Bacteria are unicellular organisms, which grow very rapidly under warmth and moisture. Further, sub divisions in the bacteria family are Gram positive (Staphylococcus aureus), Gram negative (E-Coli), spore bearing or non-spore bearing type.

Necessity of antimicrobial finishes

Antimicrobial treatment for textile materials is necessary to fulfill the following objectives:

To avoid cross infection by pathogenic micro organisms.

To control the infestation by microbes.

To arrest metabolism in microbes in order to reduce the formation odour.

To safeguard the textile products from staining, discolouration and quality deterioration.

Antimicrobial textiles
The antimicrobial textiles can be classified into two categories, namely, passive and active based on their activity against micro organisms. Passive materials do not contain any active substances but their surface structure (Lotus effect) produces negative effect on the living conditions of micro organisms (Anti-adhesive effect). Materials containing active antimicrobial substances act upon either in or on the cell.
Actigard finishes from Clariant are used in carpets to combat action of bacteria, house dust mites and mould fungi. Avecia.s Purista-branded products treated with Reputex 20 which is based on poly (hexamethylene) biguanide hydrochloride (PHMB) claimed to posses a low mammalian toxicity and broad spectrum of antimicrobial activity. PHMB is particularly suitable for cotton and cellulosic textiles and can be applied to blends of cotton with polyester and nylon.

With advent of new technologies, the growing needs of the consumer in the wake of health and hygiene can be fulfilled without compromising the issues related to safety, human health and environment. Taping new potential antimicrobial substances, such as, Chitosan from nature can considerably minimise the undesirable activities of the antimicrobial products.
Scientists all over the globe are working in the area and a few of them reported to have used antimicrobial finishes and fluoro chemicals to make the fabric having antimicrobial as well as blood repellant properties. Chitosan and fluoro polymers are reported to be most suitable finishing agents for medical wears with barriers against micro organisms and blood. To carve a niche for textile materials, this kind of value adding finishes are the need of the hour.

48

Textile Engineering / Aroma Textiles

« on: July 18, 2014, 06:53:53 AM »

We may choose various products such as fi­bres, fabrics, non-fabrics and garments to enjoy the pharmaceutical and emotional effects of aromatherapic textiles. We believe that aromatherapy and aroma­therapic textiles are the first choice for people who want to keep healthy in their daily life, and these textiles will become a fashion in the near future.

Aroma Textiles:
An ‘aroma compound’ also known as aroma or fragrance is a chemical compound that has a pleasant smell or odor. Any chemical compound has smell or odor when two conditions are met:

1. The compound needs to be volatile so that it can be transported to the olfactory system in the upper part of the nose,

2. The compound needs to be sufficiently high in concentration so that it can interact with the olfactory receptors present in the upper part of the nose which in turn transmit the stimuli to the olfactory centre in the brain where it is perceived as a pleasant or unpleasant odor.

Aroma finish is a process by which textile material is treated with the pleasant odour producing essential oils and aromatic compounds so that the wearer gets beneficial effects. Various essential oils like lavender, rosemary, and jasmine were used in this finish.

Need for Aroma Textiles:
Home textiles such as bed linens, pillow covers, bed sheets do not remain fresh due to everyday use. Also, among apparels, intimate garments and sportswear- sports t-shirts, socks and sports shoes are constantly exposed to human sweat which contains a lot of micro-organisms that give off bad odour. Hence, by some technological means, if textile materials used for the above purposes are made aroma textiles, it adds a lot of value to the product. Also, aroma compounds infuse a feeling of well-being and freshness in the wearer.
Aroma fabrics fabrics have several uses fields of medicine and alternative healing.

The sedative effects/or emotion of essential oils:

Anxiety:
Benzoin, Lemon, Chamomile. Rose, Cardamom, Clove, Jasmine

Lament:
Rose

Stimulation:
Camphor, Balm oil

Anger:
Chamomile, Balm oil. Rose, Ylangylang

Wretchedness:
Basil, Cypress, Mint, Patchouli

Allergy:
Chamomile, Jasmine, Balm oil

Distrustfulness:
Lavender

Tension:
Camphor, Cypress, Vanilla. Jasmine. Balm oil. Lavender, Sandalwood

Melancholy:
Basil, Lemon, Chamomile, Vanilla, Jasmine, Lavender, Mint, Rose

Hysteria:
Chamomile, Balm oil, Lavender, Jasmine

Mania:
Basil, Jasmine, Pine

Irritability:
Chamomile, Camphor, Cypress, Lavender

Desolation:
Jasmine, Pine, Patchouli, Rosemary


Microcapsules and Aromatherapy in Textiles:
Microencapsulation can be defined as a micro packaging technique wherein an active core material is encapsulated in a polymer shell of limited permeability. The objective of this technology is either to protect the active core material from the external environment till required or to affect the controlled release of the active-core to achieve desired delay until the right stimulus is encountered.

Market Potential of Aroma Textiles:
Fashion retailer’s interest in fragrance infused fabrics dates back to the 1960s when Kanebo, a Japanese consumer products company, manufactured women’s scented tights. In fact, hosiery and intimate apparel have been the more widely explored product categories to apply scent infused fabric technology. More recently, international companies such as Woolmark™ have formed joint ventures with the International Fragrances and Flavors association to delve into R&D initiatives with mills around the world. Woolmark™ calls its use of microencapsulation as Sensory Perception Technology™ fabrics. Woolmark™ is applying this technology to hosiery, lingerie, underwear, socks, outdoor clothing, carpeting and other interior textiles. In 2005, the Invista Company, owner of fiber brands such as LYCRA®, TACTEL® and SUPPLEX®, launched the LYCRA® Body Care Collection. The Body Care Collection includes moisturizing and fragrance features in the yarns to enhance the wearer’s sense of well being in the intimate apparel category. The micro-beads which are built into the fibers release their contents when the elastane content fabrics are stretched during wear. The Olga clothing brand launched a collection utilizing LYCRA® Body Care Collection in April 2005. The Nike clothing brand has\ also explored encapsulation methods to a limited extent. Associates have estimated that fragrance infused fabric technology, such as the one seen in the Nike Precoo System running shirt, is less than 5% of their total buy.

49

Textile Engineering / Natural Fiber Application in the Mercedes-Benz

« on: July 18, 2014, 06:33:58 AM »

Automotive natural composites
After several years of intensive research led by Mercedes Benz, the use of natural fibers in composites were found to meet or exceed the high performance demands required for strength and durability. Natural fiber composites are made of a mixture of 50% hemp and 50% polypropylene (PP) which are formed into fleece mats and are later formed into various components.
The use of natural fibers in automotive composites versus fiberglass results in both ecological and technological benefits. When compared to traditional fiberglass, natural fiber composites do not splinter on impact, use less energy to produce, have lower material cost, and are recyclable.

Natural Fiber Application in the Mercedes-Benz

Why are natural fiber substrates used in the Mercedes-Benz?
An important step towards higher performance applications was achieved with the door panels of the Mercedes-Benz E-Class and in the new M-Class and the R-Class. The wood fiber materials previously used for the door panels were replaced by a plant fiber-reinforced mat material embedded in an epoxy resin matrix.

What weight reduction was achieved by Mercedes-Benz?
Although natural fiber substrates could have been as a weight savings of up to 30%, a remarkable weight reduction of about 20% was achieved in the Mercedes.
What about the molding capabilities of the natural fiber door panels? Natural fiber substrates could be molded in complicated 3-dimentional shapes, thus making it more suitable for door trim panels than the previously used materials.

How strong are natural fiber substrates?
Although there are many considerations that go into selecting a material for any given application, from the infrastructure side, stiffness is a major design objective. Natural fiber substrates provide mechanical properties; in particular, the required stiffness and strength are important for passenger protection in the event of an accident.

Is natural fiber readily available for automotive applications?
Natural fiber, with its good availability and a comparatively low price, are increasingly cultivated specifically for industrial application. In the past where mainly by-products of the textile industry were used, primarily because of their low price, natural fibers are now increasingly used.

50

Textile Engineering / Resin finishing in textiles: (easy care/durable press/wrinkle free/wash n wear)

« on: July 18, 2014, 06:22:41 AM »

Resin finishing is a term that can be used for garments and fabrics that have been treated with specific resins that cross-link upon processing to provide an advantageous durable finish, dependant upon the resin used, various properties can be achieved such as crease recover, wrinkle resistance & recovery, shrink resistance and also reduced requirements for ironing or enhanced / easier to iron garments.

Varied legislation regarding residual formaldehyde content is a major factor when deciding which resin finish to use. Texchem have a few unique resin finishes that yield some of the lowest residual formaldehyde figures to meet certain criteria i.e. Oeko Tex finishing.

The most important aspect is chemical finishing, also known as resin finishing, easycare finishing or wash-and-wear finishing. Resin finishing has been able to maintain its position in the finishing of textiles based on cellulosic fibres despite various disadvantages such as strength losses, shade changes, reduced whiteness, and controversy about formaldehyde content.

The advantages of resin-finished over unfinished textiles, especially after washing, are:
• improved dimensional stability and shape retention
• less tendency to creasing
• easier to iron
• softer and smoother
• better appearance and therefore more durable
• less change in shade
• improved wet fastness of dyeings and prints
• less tendency to pilling, especially of fibre blends
• greater wash resistance of mechanically produced lustre and
embossed finishes and finishes with softeners, stiffening
agents, water-repellents and oil-repellents


The following different crosslinking processes are used in resin
finishing:
• Dry crosslinking process
• Moist crosslinking process
• Wet crosslinking process
• Postcure process
• Precure process
• Dip-dry process

Dry crosslinking process
The most important of these processes is dry crosslinking, in which the fabric is cured in a dry state. After being padded, the fabric is usually dried on the stenter and then cured in a curing apparatus, or on the stenter immediately after drying (flash-curing process).

Moist crosslinking process
In moist crosslinking, the fabric is cured in a moist, partially swollen state (about 6 –12% residual moisture).The fabric is padded with a liquor containing g a mineral-acid catalyst in addition to the crosslinker. The fabric is subsequently dried to a residual moisture content of 6 –12%. After being batched for one or two days at a temperature of 25– 35 °C, the fabric is washed, neutralized and dried.

Wet crosslinking process
In wet crosslinking, the reaction takes place when the fabric is in a wet,fully swollen state. Today this method is no longer used, even though it is much easier to carry out than moist crosslinking, because the dry crease recovery is almost the same as that of untreated cotton textiles.

Postcure process
The postcure process is another old process that has experienced a revival, beginning in the US. It belongs to the dry crosslinking methods and is the most significant permanent-press method. The fabric is treated as in standard dry crosslinking but not cured. The treated fabric is subsequently made up into garments and provided with crease lines or pleats in the steam press before being oven-cured.

Precure process
Crosslinking in the precure process is also carried out in the dry state. Another permanent-press method, it is a special case in which blended wovens of synthetic and cellulosic fibres (usually PES/CO or PES/CV with over 60% PES) are provided with permanent creases.
In the first step, the cellulosic component undergoes standard continuous resin-finishing by the dry crosslinking process. After making-up, the finished garment is shaped by heat setting the synthetic fibres at high temperature and under high pressure in special ironing presses.

Dip-dry process
The dip-dry process is a special case of the permanent-press or postcure process. The fabric is first made up into garments, which are dipped to impregnate them with the finishing liquor, centrifuged, dried, ironed and cured. This process has also experienced a revival. However, the curing step is difficult because of the seams, problems with yellowing, etc.

51

Textile Engineering / Different methods of flock printing

« on: July 18, 2014, 05:25:20 AM »

Flock print

The flocking process involves applying short monofilaments fibres, usually nylon, rayon or polyester, directly on to a substrate that has been previously coated with an adhesive. This print type is suitable for almost all fabric types and due to its fluffy velvet-like surface, looks and feels amazing. Flock print feels great and a bit elevated. It looks soft but is actually quite durable and does not fade. Flock retains its colours long throughout a life of regular washing at 40°C. Ironed inside out, machine drying is fine on it.

There are two types of flock -- milled and cut. Milled flock is produced from cotton or synthetic textile material. Because of the manufacturing process milled flock is not uniform in length.

Adhesives

Adhesives create most favourable effect on the quality of flocking. They make the link between the flock and the substrate. They are preferred to be soft, flexible and washproof. Today acrylate-based dispersions are significantly applied for special application, like waterproof jackets or other coated fabrics; solutions can be applied as well. Dispersion glues are distinguished between low and high temperature curing glues. At room temperature curing within two to five days, the low temperature glue dries. This denotes, after this time has passed the garment can be washed. A fixing agent has to be applied for curing. It is critical to understand the producer's instructions concerning the mixing ratio and blend the fixing agent homogeneously into the glue.
The adhesive is applied to the substrate by screen-printing. Normally, we apply a screen mesh prepared by polyester as it absorbs only less water and does not covered by the dispersion glue and in cleaning. Screen meshes of 24 T to 40 T are applied (standing for 24 to 40 threads per cm²) as the adhesive layer is comparatively thick. In against ordinary screen-printing these meshes are proved to be relatively rough, but the glues are paste likes up to thixotropic, and enough amount has to be used on the substrates.

Heat applied flock printing

Heat-applied flock print is popular for large front or back designs to give the garment a more quality appearance.

This process can be applied to:

º   Polo shirts
º   T-shirts
º   Sweatshirts
º   Fleece
º   Caps
º   Cotton, Polyester, Poly/Cotton Garments

multi-colour flocking

The methods are mentioned as below:

º   Multiple flocking
º   Cover-up flocking
º   Iris flock
º   Flock-on-flock

transfer flock

In this process the idea is to iron flocked logos on a fabric piece and is similar to transfer printing. There are many possibilities to do the same. The easy form is to flock hot-melt foils and punch out letters or logos, which are afterward ironed onto the fabric. Though this process needs costly punching tools, only larger batches of a logo can be done. The process is generally applied for the manufacturing of letters, digits and firms' logos.

Reverse method, single colour

In this process a special transfer flock paper is used, where the flock is fixed in a simply detachable way. A mirror image of the design is made with the adhesive. After that hot-melt powder is applied over the adhesive when it is wet. After it becomes dry, the design is over-turned, ie, it is put on the fabric with its hot-melt powder side onto the fabric and is afterward ironed on. The hot-melt powder mixes with the fabric, and in the part where the adhesive was imprinted the flock releases from the mover material.


Reverse method, multi-colour

This process is similar to the reverse method; single colour but here needs a transfer paper of simple white one. In this process, first the colours of the design are embossed, and then the adhesive with the hot-melt powder is applied. It is essential that the printing ink actually enter the flock. Delicate greyness on the finished transfer will make deprived quality

52

Textile Engineering / Biomimetics: A New Fresh Look of Textiles

« on: July 18, 2014, 04:30:21 AM »

What Is Biomimetics?

“The study of the formation, structure, or functions of biologically produced substances and materials (as enzymes or silk) and biological mechanisms and processes (as protein synthesis or photosynthesis) especially for the purpose of synthesizing similar products by artificial mechanisms which mimic natural ones.”
some of the most important biomimetic textiles innovations, among which fibrous structures, multifunctional surfaces, thermal insulating materials, and structurally coloured materials are mentioned.

Biomimmetics in textiles

Nature is an extremely vast database of structures and mechanisms that proved to be clearly superior to those man-made. There are numerous examples of fibrous structures, multifunctional materials, thermal insulating materials, structural colours, and many others that can serve as sources of inspiration for future sustainable textiles. In many ways, textiles offer unique opportunities to imitate nature. The base units of each textile structure at the most elementary level of the hierarchy (from nano to micro) are organic fibres, many of which are natural. In addition, like many natural functional surfaces, the textile surfaces also offer excellent opportunities for developing new functionality. All these allow an easier way to borrow the biomimetic principles of nature in textile field than in other industrial areas.

Fibrous structures of bamboo and wood, spiders and silk worm, pinecones, and even tendons (to mention just a few of them) led to the development of impressive textile structures. Superhydrophobicity, self-cleaning, and drag reduction are some of the functionalities that have been successfully integrated in textile products. Thermal insulation properties of duck feathers, penguins, and polar bears also inspired some clothing articles for cold weather. The aesthetic aspect could not be neglected, especially when it comes to clothing, so researchers turned their attention to beautiful vivid colours of butterflies, birds, and beetles. Their structural colours conducted to fascinating textile fibres and fabrics that do not require dying to display a colour, their appearance being due to light phenomena at submicron level of their architecture. Seeing the increasing number of papers related to Biomimetics topic, it is more than clear that it presents a high potential for future development of engineering, in general, and of textiles, in particular.

53

Textile Engineering / Vectran- a liquid crystal polymeric fibre in textile

« on: July 18, 2014, 04:14:44 AM »

Vectran is a manufactured fiber, spun from a liquid crystal polymer (LCP) created by Celanese Acetate LLC and now manufactured by Kuraray Co., Ltd. Chemically it is an aromatic polyester produced by the polycondensation of 4-hydroxybenzoic acid and 6-hydroxynaphthalene-2-carboxylic acid.

Usage
They are used as reinforcing (matrix) fibers for ropes, cables, sailcloth, and advanced composite materials, professional bike tires, and in electronics applications. Perhaps most notably, Vectran is used as one of the layers in the softgoods structure of NASA's Extravehicular Mobility Unit (spacesuit) designed and manufactured by ILC Dover and was the fabric used for all of the airbag landings on Mars: Mars Pathfinder in 1997 and on the twin Mars Exploration Rovers Spirit and Opportunity missions in 2004, also designed and manufactured by ILC Dover . The material is expected to be used again on NASA's 2011 Mars Science Laboratory in the bridle cables.

Vectran is a key component of a line of inflatable spacecraft developed by Bigelow Aerospace, not only on two stations which are in orbit but also the forthcoming BA-330 spacecraft which NASA has interest in testing for its life support, radiation shielding, thermal control and communications capabilities.

The United States Department of Homeland Security is sponsoring development of an inflatable plug made of Vectran to prevent flooding in the New York City Subway and other transportation tunnels, as it is strong but relatively inexpensive, and not edible for rats. Vectran fiber is also used in manufacturing badminton strings such as Yonex BG-85 and BG-80.

Production
Kuraray Co., Ltd. began manufacturing Vectran in 1990. As of June 2007, Kuraray has owned 100% of the worldwide Vectran production since 2005 when they acquired the Vectran business from Celanese Advanced Materials Inc. (CAMI), based in South Carolina, U.S.

The total capacity of Vectran expanded from about 600 tons/yr in 2007 to 1000 tons/yr in 2008.

54

Textile Engineering / Coating and lamination in textiles

« on: July 18, 2014, 04:05:57 AM »

Coating and lamination techniques are used to impart properties to fabrics which are not necessarily those naturally assumed by textile fabrics. Having widespread application across a range of technical textiles sectors, they increase functionality and durability as well as value. They can include; waterproofness, increased abrasion, stain, flame and UV resistance, retro-Reflection or Fluorescence, anti microbial or Phase Change Materials.

These functions can be imparted using a range of application methods, dictated by the materials being processed and the required outcome, whether they are applied as a coating or laminate is also determined by this criteria. The definition between the two is a technicality relating to the application method, generally coatings are applied to a fabric in their preparatory state, often in liquid form. Lamination requires the pre-preparation of a laminate membrane that is then applied to the textile.

The application for coated and laminated textiles is widespread across a variety of technical textile sectors, these include;


Automotive and Aerospace

Vehicle interiors- textiles often laminated onto interior components such as door panels.

 

Medical and Hygiene

Anti Bacterial Coatings

Waterproof breathable Hydrophilic membranes

 

Construction and Engineering

Tarpaulins

Bulk bags

 

Interiors

Upholstery- Stain resistance

UV resistance

 

Technical Apparel and PPE

Waterproof Breathable Membranes

Phase Change Materials

Fluorescence

Apparel

Fashion, luggage and accessories- textured looks such as high shine or ‘wet’ look

PVC/Faux leather

 

Sports and leisure

Sail cloth

Bouncy castles

 
Coatings and laminates will interact differently with the fabric; this is due to the way in which they affix to the textile surface. Figure A demonstrates how a coating covers the surface of the fabric, as applied in liquid form, it is able to penetrate the fabric structure, filling the air pockets and bridging the interstices. Figure B depicts how a laminate sits on the fabric surface, the fabric retains its air pockets and the laminate has fewer points of contact.
 

55

Textile Engineering / FLOURESCENT DYES

« on: July 18, 2014, 03:38:02 AM »

A fluorophore (or fluorochrome, similarly to a chromophore) is a fluorescent chemical compound that can re-emit light upon light excitation. Fluorophores typically contain several combined aromatic groups, or plane or cyclic molecules with several π bonds.

Fluorophores are sometimes used alone, as a tracer in fluids, as a dye for staining of certain structures, as a substrate of enzymes, or as a probe or indicator (when its fluorescence is affected by environment such as polarity, ions,...). But more generally it is covalently bonded to a macromolecule, serving as a marker (or dye, or tag, or reporter) for affine or bioactive reagents (antibodies, peptides, nucleic acids). Fluorophores are notably used to stain tissues, cells, or materials in a variety of analytical methods, i.e., fluorescent imaging and spectroscopy.

Fluorescein, by its amine reactive isothiocyanate derivative FITC, has been one of the most popularized fluorophores. From antibody labeling, the applications have spread to nucleic acids thanks to (FAM(Carboxyfluorescein), TET,...). Other historically common fluorophores are derivatives of rhodamine (TRITC), coumarin, and cyanine.[1] Newer generations of fluorophores, many of which are proprietary, often perform better (more photostable, brighter, and/or less pH-sensitive) than traditional dyes with comparable excitation and emission.

Additionally fluorescent dyes find a wide use in industry, going under the name of "neon colours", such as

multi-ton scale usages in textile dyeing and optical brighteners in laundry detergents
advanced cosmetic formulations; safety equipment and clothing
organic light-emitting diodes (OLED)
fine arts and design (posters and paintings)
synergists for insecticides and experimental drugs
used as a dye in highlighters to give off a glow-like effect
Solar panels (collect more light / wavelengths)

56

Textile Engineering / COOLMAX- A NEW GENERATION SPORTSWEAR

« on: July 18, 2014, 03:31:45 AM »

Coolmax, a trademark of Invista, is a brand name for a series of moisture-wicking technical fabrics developed in 1986 by DuPont Textiles and Interiors (now Invista). The fabrics employ specially-engineered polyester fibres to improve "breathability" compared to natural fibres like cotton. 'Wick away' or 'wickaway' is a general term used for fabrics that are engineered to draw moisture away from the skin through capillary action and increased evaporation over a wider surface area.

Coolmax fibres are not round, but are slightly oblong in cross-section with grooves running lengthwise along the threads. They are manufactured in either a tetrachannel or hexachannel style. The series of closely spaced channels creates capillary action that wicks moisture through the core and out to a wider area on the surface of the fabric which increases evaporation.

CoolMax fabric was originally developed for clothing intended for use during extreme physical exertion — sweat can evaporate quickly so the wearer is kept dry. Other useful properties include resistance to fading, shrinking and wrinkling. The fibres are now often woven with other materials like cotton, wool, Spandex and Tencel. As a result, CoolMax is found in a wide variety of garments from mountain climbing gear, to casual sportswear and underwear.

CoolMax fabric mattress covers and bed sheets have also been designed for those who have hot flashes or night sweating due to illness, medication or menopause.

57

Departments / Re: Published paper in USA

« on: July 18, 2014, 03:20:55 AM »

Thanks for your information sir

58

Science and Information / plasma finishing in textiles

« on: October 12, 2013, 02:29:25 PM »

What is plasma?

Irving Langmuir first used the term plasma in 1926 to describe the inner region of an electrical discharge. Later, the definition was broadened to define a state of matter in which a significant number of atom and/or molecules are electrically charged or ionised. The components present will include ions, free electrons, photons, neutral atoms and molecules in ground and excited states and there is a high likelihood of surface interaction with organic substrates. In order to maintain a steady state, it is necessary to apply an electric field to the gas plasma, which is generated in a chamber at low pressure. (Kan, 1999; Ganapathy, 2000; Pane, et al 2001; Allan, et al 2002).

Plasma, as a very reactive material, can be used to modify the surface of a certain substrate (typically known as plasma activation or plasma modification), depositing chemical materials (plasma polymerisation or plasma grafting) to impart some desired properties, removing substances (plasma cleaning or plasma etching), which were previously deposited on the substrate (Pane, et al 2001).

Plasma is any substance (usually a gas) whose atoms have one or more electrons detached and therefore become ionised. The detached electrons remain, however, in the gas volume that in an overall sense remains electrically neutral. Thus, any ionised gas that is composed of nearly equal numbers of negative and positive ions is called plasma. The ionisation can be effected by the introduction of large concentrations of energy, such as bombardment with fast external electrons, irradiation with laser light, or by heating the gas to very high temperatures.

A gas becomes plasma when the kinetic energy of the gas particles rises to equal the ionisation energy of the gas. When this level is reached, collisions of the gas particles cause a rapid cascading ionisation, resulting in plasma. If the necessary energy is provided by heat, the threshold temperature is from 50,000 to 1,00,000 K and the temperatures for maintaining a plasma range up to hundreds of millions of degrees. Another way of changing a gas into plasma is to pass high-energy electrons through the gas. The individually charged plasma particles respond to electric and magnetic fields and can therefore be manipulated and contained. The atmospheres of most stars, the gas within the glass tubing of neon advertising signs, and the gases of the upper atmosphere of the earth are examples of plasmas. On the earth, plasmas occur naturally in the form of lightning bolts and in parts of flames.

There are many different ways to induce the ionisation of gases. (1) Glow discharge, (2) Corona discharge, (3) Dielectric Barrier discharge.

Various plasma technologies used in textile

There are many different ways to induce the ionisation of gases.

(1) Glow discharge,
(2) Corona discharge,
 (3) Dielectric Barrier discharge,
(4) Atmospheric pressure plasma technique.


Various application of plasma in textile.

APPLICATION                      MATERIAL                             TREATMENT
Hydrophilic finish             PP, PET, PE                           Oxygen plasma, Air plasma
Hydrophobic finish             Cotton, P-C blend                   Siloxane plasma
Antistatic finish              Rayon, PET                        Plasma consisting of dimethyl silane
Reduced felting             Wool                                    Oxygen plasma
Crease resistance             Wool, cotton                            Nitrogen plasma
Improved capillarity             Wool, cotton                            Oxygen plasma
Improved dyeing               PET                                    SiCl4 plasma
Improved depth of shed       Polyamide                            Air plasma
Bleaching                               Wool                                  Oxygen plasma
UV protection                    Cotton/PET                          HMDSO plasma
Flame retardancy       PAN, Cotton, Rayon            Plasma containing phosphorus

59

Science and Information / Sun Protective Clothing in the Prevention of Skin Cancer

« on: September 28, 2013, 09:37:37 AM »

UV Protection Factor or "UPF"

The Ultraviolet Protection Factor (UPF) rating system measures the UV protection provided by fabric. It is very similar to the SPF rating system used for sunscreens.

A garment with a UPF of 50 only allows 1/50th of the UV radiation falling on the surface of the garment to pass through it. In other words, it blocks 49/50ths or 98% of the UV radiation.



 Here are details of the specific test standards.

    American Association of Textile Chemists and Colorists (AATCC) Test Method 183 specifies the protocol for conducting a UV transmittance test;
    American Society for Testing and Materials (ASTM) D 6544 describes the methods used for evaluation of a fabric's life cycle UV protection;
    American Society for Testing and Materials D 6603 provides guidelines for labeling sun protective clothing.


The Need for UV Testing

Certification of UV protection levels is needed as most regular summer clothing rates below a SPF 30 sunscreen in terms of UV protection. For example, Gambichler et al published a comprehensive analysis of regular Summer clothing in BioMed Central in 2001. They examined the level of UV protection provided by 236 different articles of clothing and found that fewer than half the fabrics provided as much protection as a SPF 30 sunscreen. They concluded it was difficult for sun-aware consumers to choose the "right" garments unless they were tested and labeled in accordance with appropriate standards.

In Australia, both sunscreens and sun protective garments are regulated by Federal agencies. The program for sun protective garments is administered by an agency named ARPANSA - an agency similar to the EPA. ARPANSA developed Australian/New Zealand Standard 4399 which is the original globally recognized standard for sun protective clothing. In the US, while the FDA regulates sunscreens, there is presently no Federal program for sun protective garments. However, there are AATCC and ASTM standards described above that manufacturers may follow on a voluntary basis.
Factors Affecting Fabric UV Protection Levels

There are a number of factors that affect the level of ultraviolet protection provided by a fabric and the UPF rating. In order of importance these are: weave (tighter is better), color (darker is better), weight (also called mass or cover factor - heavier is better), stretch (less is better) and wetness (dry is better). The other major factor that affects protection is the addition of chemicals such as UV absorbers or UV diffusers during the manufacturing process. Many factors that make a garment comfortable also make it less protective. The major design challenge for sun protective clothing is how to combine comfort, style and protection in the one garment.


Most summer clothing exposes large amounts of skin to the sun. A major goal for all Coolibar's UV protective clothing and UV protective swimwear designs is to cover as much skin as possible while still making the garment cool and comfortable to wear. Our designs use hidden ventilation and specialized moisture managing UPF 50+ rated fabrics to achieve these dual goals of comfort and maximum skin coverage.

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Science and Information / Sun protective clothing

« on: September 28, 2013, 09:30:41 AM »

Sun protective clothing is clothing specifically designed for sun protection and is produced from a fabric rated for its level of ultraviolet (UV) protection. A novel weave structure and denier (related to thread count per inch) may produce sun protective properties. In addition, some textiles and fabrics employed in the use of sun protective clothing may be pre-treated with UV inhibiting ingredients during manufacture to enhance their UV blocking capacity.

Not only limited to UV-inhibiting textile use, sun protective clothing may also adhere to specific design parameters – including styling appropriate to full coverage of the skin most susceptible to UV damage. Long sleeves, full collars, and full-length trousers and skirts are common styles for clothing as a sun protective measure.

A number of fabrics and textiles in common use today need no further UV-blocking enhancement based on their inherent fiber structure, density of weave, and dye components – especially darker colors and indigo dyes. Good examples of these fabrics contain full percentages or blends of heavy weight natural fibers like cotton, linen and hemp or light-weight synthetics such as polyester, nylon, spandex and polypropylene. Natural or synthetic indigo dyed denim, twill weaves and canvas are also good examples. However, a significant disadvantage is the heat retention caused by heavier weight and darker colored fabrics.

As sun protective clothing is usually meant to be worn during warm and humid temperatures, some UV-blocking textiles and clothing may be designed with ventilated weaves, moisture wicking and antibacterial properties to assist in cooling and breathability.