Smart materials are the materials, which can sense and react to environmental conditions. According to the manner of reaction, they can be divided into three categories.
· Passive Smart : Sense environmental conditions.
· Active Smart : Sense and react to the environmental conditions.
· Very smart : Sense, react and adapt to the environment conditions.
Smart materials are reactively new compared with structural and functional material. Since the formal introduction of the concept in 1989 most advance industrial countries have actively supported research and development in this area. Application of these materials have led to a wide range of new products in aerospace, transportation, telecommunication, home, building, infrastructures, textile and clothing. The product example for smart textile and clothing are numerous like smart glass frames, wearable electronics, smart car seat belts, skins for sound absorption and vibration control etc. Wearable electronics are one step a heat in field of application of smart fabric.
The dividing line between high performance textiles, or even “smart textiles”, and technical textiles should be drawn roughly ;in accordance with market segments. Everything which serves human well-being in the broadest sense.
The technical textiles Grey zone beings where the characteristics not only have an effect on human well-being but perform protective function, as textiles do in the field of medicine for example.
Material science has undergone a distinct trend from the development of structural material of functional materials with “intelligent materials”. Smart or intelligent materials are  “materials which respond to environmental changes at the most optimum conditions, and manifest their functions according to changes”. Smart materials are not perfect systems. However, smart materials are used as part of a whole, allowing for the development of higher-grade systems; Systems with more acute recognition, discrimination, and reaction capabilities,
At the basic level intelligence in materials consists of three functions
· Effector or actuator
All supported by more primitive functions like
· Systematic information transfer
· Energy conversion and supply
· Function and structures at the most rudimentary level of Physics and Chemistry.
Materials with variable properties.
· Surface color or luster varies according to applied load.
· Appearance varies according to internal degree of creep, fatigue, or radiation damage.
· Mechanical or electrical properties vary according to surroundings.
· Mechanical or electrical properties vary according to applied load.
Materials with variable structure or compositions.
· Chemical composition varies according to surrounding and operating conditions.
· Chemical composition varies according to degree of damage from radiation, corrosion, or break down voltage.
· Phase diagram varies according to its surroundings.
· Materials with variable functions :
· Electric threshold varies according to applied or loading conditions.
· Electric threshold varies according to type of signal and its origin.
· Optical threshold varies according to the amount of light and its wavelength.
· Permeability to a particular gas varies according to its surrounding.
Materials with systematized functions :
· All around sensor materials that can detect various signals.
· Can adjust sensitivity according to environmental changes.
· Can restore degraded sensitivity.
· Catalytic material that can detect progress of reaction.
· Catalytic material that can distinguish the reaction product then disappear.
· Textile materials that can be detect varies singles from the human body and weather conditions to offer great comfort.
A major step forward in the science of clothing was the introduction of the concept of clothing insulation. This concept not only made possible measurement of the dry insulation value of clothing but also stimulated calculation of the insulation necessary maintain heat balance between man and any given environment when his heat production level was specified. Since man’s metabolic heat production varied by a factor of abut 5 or 6 times, depending on his activity, the required insulation value of his clothing also varied by this factor. The consideration led to the layer principle of clothing is which the clothing was designed as a number of layers which could be successively removed when man was active to adjust the insulation value of his clothing to appropriate amount.
It soon become evident, however, that the limiting factor was not the amount of sweat secreted but amount that be evaporated. In hot humid environments, high humidity slows the evaporation of sweat. In cooler climates, the clothing worm provides an impedance to the evaporation of sweat; the colder the climate the greater is the amount of clothing and the greater the impedance to evaporation.
Creative engineered sports garments based on a systematic scientific approach have been decisively proven to enhance such performance and achievement.
It has been found in practice that, when clothed man sweat during activity, some of the sweat accumulate in his clothing. When he returns to an inactive or resting state, the heat production decreases and he no longer requires evaporative cooling. Sweating ceases, but the moisture that was accumulated in his clothing continues to evaporate and provide unwanted cooling. This is the situation similar of the man standing inactive in damp clothing after exercising vigorously and getting cold and will be termed after exercising chill “It is a transient situation, since his clothing is gradually drying, and it cannot be investigated by any steady-state type of experiment. In case of naked man any increase of sweating is immediately accompanied by an increase in heat loss due to evaporation. Similarly any decrease in sweating is immediately accompanied by decrease in heat loss. Thus the naked man has a control of his heat loss which has no appreciable time lag.
Anyone producing sportswear needs to look at the whole system, each layer of textile must be compatible with the others. Only with all factors working together can perfect performance be achieved. Information on all inter-relationship is needed from the yarn producer right through to the retail counter. Each sport has its own particular needs as shown in Table 1. Four functions are predominant ;
1. Protection : from wind, water and adverse weather
2. Insulation : protection from cold
3. Vapor permeability : To ensure that body vapor passes
outward through all layers of the clothing system
4. Stretch : to provide the freedom of movement
necessary in sports.
1. Shirts for tennis, volleyball, golf, (+slacks), football, rugby, baseball uniform, track suits.
2. Skiwear, wind breakers, rainwear
3. Skiwear, wind breakers, tracksuits
4. Swimming race and skating costume, skijump and downhill skiing suits, cycling costumes
5. Swimwear, leotards, skating costume
6. Skiwear, snowboard wear, baseball uniform, football uniform.
Sweat absorbing, fast drying cooling
Vapour permeability, water proofing
Sunlight absorbing and thermal retenting.
Low fluid resistance
(for water and air)
High tenacity, heat resistance to absarsion.
Heat transfer associated with evaporation was recognized as one means whereby a man could at least theoretically adjust his heat loss to match his metabolic heat production. Each unit quantity of sweat evaporated from the skin removes a quantity of heat equal to the latent heat of evaporation. Examination of physiological literature shows that man can secrete sufficient sweat to remove all metabolic heat produced during sustained exercise provided the sweat is all evaporated. This is man’s major method of dissipating heat in hot environments.
Sunlight-absorbing and thermal-retention garment-material which positively absorb sunlight and transform it into thermal energy can be applied for skiwear. The pioneer of this category of product is “Solor-a” by Unitika, in which carbonized zirconium is incorporated in the core portion of a conjugated polyester yarn to facilitate warmth retention inside the garment. Furthermore, special engineered garments for mountain climbing and to withstand extreme cold weather to retain heat via control of thermal circulation transmission and radiation by utilizing a high density hollow microfibre with a metallic vapor coating.
The specification profile in functional sportswear and leisure wear provides the basis for the ideal product. Clothing physiology is the mechanism of interactions between the human body and its clothing system. The aim is to provide information on the physiological properties of clothing. These are expressed in terms of comfort, and performance capability and health of the wearer. Clothing that is physiologically right embodies the correct functioning of the clothing whilst physical activity is taking place. Its is governed by the correct interaction of
- spinning, weaving or knitting parameters.
- Fabric density, thickness and weight
- Garment fit
- Make-up technique
For those seeking comfort and healthy pursuits, critical features include thermal retention, UV-resistance, cooling capacity, sweat absorption and fast drying, vapor permeability, water proofing, and anti-bacteria/odour to provide relaxation without fatigue. From the sensitivity viewpoint, surface texture, handle, lustre, colour variation, transparency and comfort in wear are important factors in fabric engineering.
Generally speaking clothing comfort is governed by the interplay of three components :
The human body, its microclimate and its clothing form a mutually interactive system. The body and its microclimate are invariable, the clothing system is the only variable. To prevent the body temperature exceeding the comfort zone the hat must simultaneously be dissipated outwardly. The human body has no problem exerting half a litre or even a whole litre perspiration per hour provided that this process is not impeded by the high relative humidity of its environment and the vapor impermeability of its clothing. It is clear that the clothing is the key to body comport. The most important needs in clothing in general and functional sportswear in particular are therefore.
Body vapor must have the opportunity to pass immediately from the skin to the outer surface of the clothing. Many fibers are capable of doing this in dry state. But problem starts with perspiration.
In contrast to man made fiber, natural fibers become saturated. The body vapor and perspiration fail to pass through the fibres which are virtually “stacked together”
Man-made fibres have enlarged the spheres of application of these products from simply apparel clothing to industrial and various high-tech fields owing to the high potential for “scientific creation”.
It is important to notice that the basic structural design elements are related with fibre structure including material, yarn and fabric structure.
Functionally correct clothing needs to meet the following requirements :
- Maintain a comfortable microclimate in terms of temperature and humidity in the skin sensory zone.
- Good absorption of moisture and ability to transmit moisture vapor
- Absence of unpleasant odour (perspiration)
- Compatibility with the skin
- Good extensibility without restricting mobility
- Good fit stability
- Low intrinsic weight (not impairing physical performance)
- Fabric substantially water-repellent and dirt-repellent
Heat transfer was influenced by the mass of the sample, the packing destiny of fibre assembly and the geometry of the constituent fibres. The dynamic water vapor sorption behavior of fabrics in the transient state therefore is not the same as of single fibres because of the heat of sorption and then factors influencing the dissipation of the heat.
The process of moisture diffusing into a fabric is coupled with heat transfer process. The strength of the coupling effect depends on the degree of fibre hygroscopicity. The coupling effect between moisture diffusion and heat transfer to depend on number of fibre properties : moisture sorption capacity (isotherm), diameter, water vapor diffusion coefficient, density and heat of sorption, most of which are functions of water content./
Natural fibers become saturated with perspiration, sometimes carrying up to 50% of their own weight. This is undesirable when the body is under stress. It causes the body to feel unpleasantly chilled, even under the conditions of high heat. Man-made fibres with their hydrophobic (water repellent) characteristics are ideal for sportswear. The natural fibres are used mainly for absorbing and transporting body vapor.
Superfine or microfibre yarn enable very dense fabrics to be produced in which the spaces between fibers are becoming every smaller. The specific fabric or fibre surface areas is also extended, producing more pores to transport vapor out by their superior capillary action. The higher pore density also provides better thermoregulation. Most vapor transport mechanism are governed by yarn and fabric structures. The finer the fibrils,
- the greater the specific surface are
- the greater the vapor transmission
- the lower the flexing resistance
- the softer the handle
- the greater the crease acceptance
- the greater the fabric density, and
- the greater the cover
The main functions of sportswear fabrics are to protect from wind and adverse weather as well as to insulate. Most woven fabrics for weather protection used to be polyvinyl chloride coated. The PVC coating guarantees absolute water proofness but it has one serious drawback-it does not allow air to permeate.
Knitted fabric possesses stretch, providing full freedom of movement, and in particular has two important function to perform, namely provide unrestricted freedom of movement and transmission of body vapor to the next textile layer in the clothing system With new combinations of fabrics and yarns and with developments in fabric construction, knitted fabrics appear to be the ideal base for functionally correct sportswear. Knitted garments are mainly worn next to the sk and therefore deserve particular attention. Smooth fabrics lies flat against the skin and the perspiration film causes the fabric to stick to the skin. The less the direct contact with skin, the greater the wicking action. Loops or rib are best. Double-knits and double jerseys, are ideal. The inner surface of the fabric usually comprises textured man-made fibres or spun yarns with the outer surface generally cotton. The capillary action of the hydrophobic man-made fibre yarns carry the body vapor unimpeded outward where the moisture is absorbed by the cotton. This provides immediate removal of perspiration from the skin. Moisture is then able to evaporate unhindered. The skin is not damp and the weather is comfortable.
Comfort is a state of well being and a comfortable garment is one which can be argued to be unnoticeable by the wearer when worn. Comfort using textiles entails three main consideration ; psychological, sensorial and thermo-physiological.
Consumer prejudice, colour and prevalent fashion generally influence this aspect.
This involves the tactile sensation of a garment on the human body. Garments that are of good fit, soft or non abrasive are sensorially comfortable. This aspect of comfort depends upon fibre, yarn and fabric structural properties , as well as the finishing, coating, lamination, etc processes applied to the fabric.
Thermo-physiological comfort entails both thermoregulation and moisture management. This is achieved by using garments to maintain the human body temperature and moisture output as far as possible to its normal level under diverse environmental conditions. Many popular sports of high metabolic heat outputs, such as football, tennis and basketball to name a few are now played at international level in countries with climatic conditions that are very different from each other. Since it is not practical to design sportswear garment to cater for individual climatic conditions, it is possible to fashion garments that will not unduly hinder the overall efficiency of a sportsperson irrespective of climatic conditions. Metabolic output (energy expenditure) of some sporting activities is given in table .
Sporting activities where metabolic heat outputs are high generally require cooler climate for comfort, but as mentioned above it is not possible to control outdoor
Energy expended, watts m-2 hr-1
Climbing and Mountaineering
Cross country running
Environmental conditions, therefore sweating and evaporation of sweat is the only other means for body cooling. A sportswear garment should be designed in such a way that it will not impose undue limitation on these important aspects of comfort through body cooling by the evaporation of the sweat. The sportswear garment should in addition exhibit low resistance to heat transfer, it should also have a low resistance to evaporative heat loss, or in other wards, it should have a low resistance to evaporative heat loss, or in other words, it should have a high degree of water vapour permeability.
RESPONSIVE SPORTSWEAR GARMENTS
The worldwide growth in sportswear and leisurewear has been widely recognized, but specific figures have only recently been quoted as regards its dramatic expansion. According to Pierre Duffar; DuPont’s European active sportswear manager, worldwide growth in the clothing area was 75 per cent between 1987 and 1998, with an anticipated further growth of 23 per cent from 1997 to 2001. Sportswear in Europe is worth an estimated DM 30 billion with an average growth rate of 30 per cent. Jogging suits, tops, track suits and socks account for 70 per cent sales .
A number of following desirable attributes of functional sports and leisurewear have been identified  :
· Optimum heat and moisture regulation.
· Good moisture absorption and moisture conveyance capacity.
· Good air and water vapour permeability.
· Prevention of a long-term feeling of dampness.
· Low water absorption of the layer of clothing facing the skin.
· Quick drying fabric to prevent catching cold.
· Pleasant to the skin, soft, non-abrasive and non-chafing.
· Stable as to shape, even under wet conditions.
· Low intrinsic weight.
· Easy care
A number of multilayer structures including a raised three-thread 3 x 1 weft knitted fleece fabric comprising of staple-fibre polypropylene fleece yarn, CoolMax polyester filament tie-in yarn and cotton ground r face yarn and also the above structures produced in 100 % Tactel polyamide yarn but used in the unraised state have been developed and fully characterized during this research programme.
The test results presented in Figure 1 illustrate the effect of application of appropriate finish to a 3 x 1 weft knitted fleece fabric on the recovery behaviour of its dry thermal resistance capability after the fabric has been wetted out with water. It will be noticed that in the untreated state it takes 20 minutes to recover 75% of the fabric’s dry thermal resistance value. This property can be significantly improved by the application of 2% w/w hydrophilic softener (Sandotor HV, designed specifically for synthetic fibres). This results in a 75% recovery of the thermal resistance of the fabric system, illustrated in Figure 1 within 4 minutes of wetting. This rapid recovery is indication of a truly “dynamic” system. The use of an appropriate hydrophilic reagent for these fabrics is imperative. Application of a hydrophilic softener designed for cellulosic fibres (2% Alkosoft) produces a different rate of wicking. In this case it takes 22 minutes to recover 75% of the fabric’s dry thermal resistance value. This aspect of moisture management was also confirmed by using the same hydrophilic softener (2% w/w Sandotor HV hydrophilic softener) on a 100% Tactel polyamide 3 x 1 fleece three-thread construction, but used in the unraised state. The fabric was able to recover 75% of its dry thermal resistance value within 4 minutes of having been wetted.
One example each of a two layer and a three layer system, together with the type of material used in each individual layer of the assembly have been illustrated in Figure 2. The full range of appropriate properties of a 100 per cent filament polyester football shirting fabric finished conventionally, and the same fabric finished with a special hydrophilic softener developed specifically for synthetic fibre are compared in Figure 3. A close examination of the various test results revealed that the special finish applied to a standard football shirt did not affect the majority of the properties or performance standards exhibited by the original finished fabric. It however, significantly improved the water absorption and wicking properties, as shown in figure 3.
It must be remembered that any special finish applied to a sportswear fabric or garment must be quick drying and, what is even more crucial, it must be durable to repeated laundering i.e. machine washing and tumble-drying operations, as well as industrial dry cleaning.
CONCEPT OF WEARABLE COMPUTING OR ELECTRONICS
A wearable computing is a new form of human-computer interaction, an important application area of Textiles. The wearable computer is more than just wristwatch or regular eyeglasses. But it has the full functionality of computer systems.
Operational mode of wearable computing
There are three operational modes in this new interaction between human and computer.
The computer runs continuously and is “always ready” to interact with the user. Unlike a hand-held device laptop computer, or PDA. It doesn’t need to be opened and turned on prior to use. The signal flow from human to computer, and computer to human runs continuously, to provide a constant user interface.
Traditional computing paradigms are based on the notion that computing is the primary task. Wearable computing however, is based on the notion that computing is not the primary task. The assumption of wearable computing is that the user will be doing something else at the same time as doing the computing. Thus computer should serve to augment the intellect or augment the sense.
Unlike hand held device, laptop computers, and PDA, the wearable computer can encapsulate. It doesn’t necessarily need to completely enclose us, but the concept allows for a greater degree of encapsulation than traditional portable computer (Figure 1©). In embodiments of wearable computing that are actually articles of clothing in direct contact with our flesh, it may also make measurements of various physiological quantities. To make the signal flow more explicit as shown in fig. 1c. Can be redrawn as shown in fig. 1 (d).
Where computer and human are depicted as a two separate entities within an optional protective shell, which may be removed or partially removed if a mixture of augmented.
Wearable computing is a framework for enabling various degrees of each of these fundamental modes of operations. Collectively, the space of possible single flows giving rise to entire possibility as shown in fig. 1 (e).
There are six informational flow paths associated with this new human – machine interaction. They are in fact, attributes of wearable computing and are listed below .
1. UNMONOPOLIZING of the user’s attention
2. UNRESTRICTIVE to the user
3. OBSERVABLE by the user
4. CONTROLLABLE by the user
5. ATTENTIVE to environment
6. COMMUNICATIVE to other.
Using above concept some of earlier wearable computers developed are shown in picture (View I to III). But the new concept of manufacturing trend of wearable computer are to weave specified design to give the circuits, merge IC seamlessly in fabric and Develop fabric Keyboards.
BASIC STRUCTURE OF FABRIC USED FOR WEARABLE ELECTRONICS OR COMPUTING
Wearable computers can now merge seamlessly into ordinary clothing. Using various conductive textiles . Data and power distribution as well as sensing circuitry can be incorporated directly into was and wear clothing. We know that tactile and material properties of what people wear are important to them, and people are reluctant to have wires and hard plastic cases against their bodies. To this end many attempt has been made to build electronic circuits entirely out of textiles to distribute data power, and perform touch sensing. Some structural view of wearable computers used is shown in Figure 2.
For years the textiles industry has been weaving metallic yarns into fabrics for decorative purpose. The first conductive fabric we explored was silk organza, which contains two types of fibers. In the warp is a plain silk thread. Running in the other direction on the weft is a silk thread wrapped in the thin copper foil. This metallic yarn is prepared just like clothcore telephone wire, and is highly conductive. The silk fiber core has a high tensile strength and can withstand high temperatures, allowing the yam to be sewn or embroidered with industrial machinery. The spacing between these fibers also permits them to be individually addressed, that strip of this fabric can function like a ribbon cable. Circuits fabricated on organza only need to be protected from folding contact with themselves, which can be accomplished by coating, supporting or backing the fabric with an insulating layer which can also be a cloth. Also, circuits formed in this fashion have many degrees of flexibility (i.e. they can be added up), as compared to the single degree of flexibility that conventional substrates can provide.
There are also conductive yarns manufactured specially for producing filters for the processing of fine powders. These yarns have conductive and cloth fibres interspersed throughout. Varying the ratio of the two constituent fibers leads to differences in resistively. This fibers can be sewn to create conductive traces and resistive elements.
While some component such as resistors, capacitors, and coils can be sewn out of fabric, there is still a need to attach other components to the fabric. In micro controller a PIC 16C84 as shown in fig. (3) [W] Surface mounted LED’s, crystals, piezo transducers, and other surface mount components with pads spaced more than 0.100 inch apart are easy to solder into the fabric. Once components are attached, their connections to the metallic yarn may need to be mechanically strengthened. This can be achieved with an acrylic or other flexible coating.
Several circuits have been built into the fabric to date, including busses to connect various digital devices, micro controller systems that sense proximity and touch, and all – fabric keyboards and touch pad as shown fig. (4) & (5).
· In the micro controller circuit a PIC16C84 and its supporting components are soldered directly onto a square of fabric. The circuit uses the bi-directional I/O pins on the PIC to control LED’s and to sense touch alone the length of the fabric, while providing musical feedback to reinforce the sense of interaction. Building systems in this way is easy because components can be soldered directly onto the conductive yarn. The address ability of conductors in the fabric makes it a good material for prototyping, and it can simply be cut where signal lines are to terminate.
· One kind of fabric keyboard uses pieced conductive and on conductive fabric, sewn together like a quilt to make a row and column addressable structure. The quilted conductive columns are insulated from the conductive rows with a soft, thick fabric, like felt, velvet, or quilt batting.
· Keyboards can also be made in a single layer of fabric using sensing , where an array of embroidered or silk screened electrodes made up the points of contact. Capacitance sensing arrays can also be used to tell how well a piece of clothing fits the wearer, because the signal varies with pressure.
· The wearable gives the advantage of unparalleled computing power and stored data with a negligible increase in weight. Using to improve the situational awareness of mounted or dismounted troops, including the Special Forces. The wearable is the next advancement on the digitized battlefield. Troops can use global positioning satellite interfaces to provide themselves and their commanders with their precise locations, report critical data on threats, and keep in close contact with the chain of command to receive orders, make reports, and request supplies.
· The wearable allows emergency medical personnel to implement “Tele medical” applications on the battlefield or in trauma care centres. In the field, personnel are able to obtain vital signs and critical medical information about a casualty via an interface to the soldiers “Mediate”[w]. Combat medics can them consult with physicians at a facility via. The wearable and military communications systems to obtain medical advice and treatment protocols. Diagnosis, documentation of casually care, prescriptions, and access to other physician guidelines can be fully automated. Access to information and treatment of peculiar diseases in the theater of operation can be resident on the wearable, enabling medical personnel to take appropriate with troops.
· Every aspect of airline operations today is being squeezed for maximum, efficiency. Maintenance personnel in particular are under pressure to cut costs, reduce waste, or speed aircraft turnaround. For applications like these [w], Computing Devices International developed the wearable computer. These remarkable ultra-lightweight individuals who demand mobility, this computer offers voice control and head up display for complete, hands free operation. Users can enter or retrieve information while on going about their jobs, instead of constantly returning to the shop area to check a stationary computer, or stopping work to punch keys.
ASPECTS OF WEARABLE COMPUTING AND PERSONAL EMPOWERMENT
· Photographic memory : Perfect recall of previously collected information.
· Shared memory : In a collective sense, two or more individuals may share in their collective consciousness, so that one may have a recall of information that one need not have experienced personally.
· Connected collective humanistic intelligence : In a collective sense, two or more individuals may collaborate while one or more of them are doing another primary task.
· Personal safety : In contrast to a centralized surveillance network built into the architecture of the city, a personal safety system is built into the architecture (clothing) of the individual.
· Wireless operation : Wearable computing mobility, and the freedom from the need to be connected by wire to an electrical outlet, or communications line.
· Synergy : Rather than attempting to emulate human intelligence in the computer, as is a common goal of research in Artificial intelligence, the goal of computing is to produce a synergistic combination of human and machine. Over an extended period of time, the wearable computer begins to functions as a true extension of the mind and body, and no longer feels as if it is a separate entity. In fact, the user will often adapt to the apparatus to such a degree, that when taking it off, its absence will make uncomfortable. Synergy, in which the human being and computer become elements of each other’s feedback loop, is often called Humanistic Intelligence (HI) (3).
· Quality of Life : Wearable computing is used, not just in the workplace, but in all feats of daily life. It has the capability to enhance the quality of life for many people.
Development in heat retention and exothermic functions for sportswear and leisure clothing form the centre point, especially in Japan (fig. 8) during this season. Passive heat retention is achieved by numerous pores in the textile product interior by means of bulked and microfibre constructions which absorb sunlight and ultra-violet rays.
Active heat retention
The current new ideas for this type of textile include active heat retention, and active exothermic functions. In conjunction with fibre producers and textile finishers, sportswear producers are particularly active this season in promoting these products. In conjunction with Toyobo Co. (j), Mizuno Corp. (J) is marketing the “Breath-thermo” product, which consists of a polyester fibre cross linked with polyacrylics. The Chemical applied is also used as a drying agent for medical applications. The material has therefore an effective water absorption capacity and exothermic characteristics which occur due to the molecular friction of the water. The temperature in the textile interior can consequently be 2 to 3 oC higher than in conventional textile products.
About 900 cm3 of water evaporates from the human skin surface daily, even without sweating. “Breath-thermo” uses this water to heat up the interior of the clothing. Mizuno first of all introduced this product to the market as a filler for ski clothing at the 1994 Winter Olympics in Lillehammer (N), and, since then, has improved the woven textile application possibilities.
Mizuno plans to market this branded fabric for mountain sportswear, active sportswear and golf equipment. Descente (J) and Adidas Japan have used another Toyobo fibre type, the “Exlive’ fibre, which contains acrylate powder with a grain size of 0.2 m. This material has a three times higher water absorption capacity than silica gel, and offers important exothermic characteristics due to its water absorption capacity.
The “Warmsensor” woven fabric types containing special ceramics developed by Toray Industries (j) form the basic material for a three layer construction with absorptive, insulating and heat repellent layers, the effective heat retaining capacity of which is 2 to 3oC higher than with other conventional textile products. Asics Corporation (J) has processed this material into sports underwear, underwear and ski clothing. “Porlatech”, clothing with an integral lithium battery, was presented by Malden Mills at ISPO 2000 for the first time. The thin heater plate can produce heat for five hours, keeping the garment warm. Goldwin Co. (J) is starting to market this product during this winter season.
Snow jacket with an integral heating system
During the 1998 Winter Olympics in Nagano, Japan, 200 members of the Swiss team and 300 press representative wore the Descente “Mobile Thermo” snow jacket (fig. 4) with an integral heating system inside the garment which guaranteed precise temperature control in the interior. These are the intelligent electronic systems for clothing described above. The “Thermocatch” heat insulation system development by Mitsubishi Rayon (J) with acrylic fibres contains in the fibre core fine ceramic particles which convert light into heat, and with an antimony/stannic oxide component in the fibre sheath.
The admixture of 10% of these fibres to conventional fibres results in a 2 to 8oC higher temperature inside the clothing. Quick drying and excellent electrical conductivity are other noteworthy advantages. Some finishers use coating processes to obtain similar exothermic effects by introducing a special ceramic component or an acrylic product into the coating.
Multi-layer composite yarns and textiles
Multi-layer composite yarns and textiles are another physical possibility for achieving clothing wear comfort. These composites are designed to absorb sweat given off from the human skin surface by an from the human skin surface by an internal sweat-absorbent layer. One solution already converted to practical use is the Toyobo “Cool & Dry” three-layer composite yarn, which consists of a polyester filament yarn on the surface, a staple fibre polyester yarn in the middle section and a polyester filament yarn on the inside, the finest components lying in the middle. Fine fibres offer greater porosity, which increases capillary action, conveying the absorbed sweat (or moisture) to the yarn surface.
Toyobo “cool & Dry” knitted fabrics result in significantly lower body temperatures than conventional cotton/polyester blend knitted fabrics. The coarse polyester filament yarn in the yarn interior has a Y-shaped cross-section in order to increase moisture absorption capacity. Some cotton textile producers have developed a similar three-layer construction, in which different fibre finenesses are used to facilitate moisture conveyance from inside to outside. However, they use a pure cotton yarn for the inner component in order to improve absorption capacity.
A fine polyester filament is used in the middle layer however in order to accelerate moisture conveyance. For developing this type of multi-layer construction, the key factor is a combined yarn production process composed of a combination of staple fibre spinning and filament feed-in with an ultimate doubling and twisting process.
The most difficult process is producing composite yarn covered with a filament yarn. The most important parameter for adequate processability is the optimum angle of twist during the process. The textiles presented for moisture absorption form part of the intelligent textile concept which triggers some activity on the part of textile producers for the production of comfort clothing.
As mentioned above, the increasingly stringent market requirements not only have a decisive effect on the further development of yarns and woven and knitted fabrics but on entire clothing systems too. One outstanding example of intelligent clothing is the child’s overall (fig. 5) by the Finnish clothing manufacturer Reima-Tutta Oy, which made a big entrance at the first “Avantex”.
The “Reimatec” fabric, woven from DuPont (USA/CH) yarns, is water proof, wind-repellent and can breathe, i.e. it lets moisture out but no wetness sin. Almost every seam is adhesively closed and therefore watertight. The material consists of polyamide, which water droplets cannot penetrate because of the microporous polyurethane coating on the outside, though water vapour can escape through the fabric to atmosphere. “Reimatec” revealed the following test results :
- Water column over 6000 mm (3000 mm counts as waterproof)
- Breathing activity over 300 g/m 2/24h
- Trouser abrasion resistance 8900 revolutions, other parts 4700 (Stoll).
Another project is called “Reima Smart Shout”, and will make possible simple group communication based on GSM technology. The equipment is like a telephone extension. The concept was developed by Reima-Tutta Oy in confection with Tampere Technical University (SF) and Nokia (SF).
Application fields range from sportswear, e.g. snowboarders and skiers to clothing beneficial to children and older people. In this way, wearers can be reached anywhere at any time, which is particularly desirable in emergency situations.
The integration of microsystem technology in clothing is without doubt one of the most interesting development, Integral sensor systems in clothing will be of great importance in the future. They will make it possible to monitor blood pressure, heart rate or body temperature continuously. The data can be read radio telegraphically directly into a doctor’s computer making remote monitoring possible.
Plasma treatment plus coating Plasma treatment is a relatively new textile surface treatment technology. With its new plasma production technology. Textilausrustungs – Gesellschaft Schroers GmbH & Co. KG in Krefeld (D) (TAG) is offering diverse possibilities of finishing textiles, nonwovens, foamed material and films from low-energy plastics.
The wetting behaviour of coating agents and adhesives and also the ageing-resistant adhesion of the plastics applied are significantly affected by plasma treatment, and are improved by the increasing surface energy of the treated fabrics. Through treatment with plasma from air, the surface energy of the above-mentioned materials is increased in the continuous process in such a way that coating this fabric results in products which are distinguished by drastically improved adhesion of the plastics applied.
One advantage of plasma treatment is the possibility of modifying homopolar and insoluble thermoplastic plastics (e.g. PE, PP and PP) Plasma pretreatment is helpful when adhesion needs to be improved in sticking, lacquering and laminating and also in material coating or printing. Parting agents and lubricants, size and softeners can be removed, and composites are endowed with better characteristics.
Use of the ceramic coating system in the form of so-called “fluid ceramics” is currently limited to thermoceramic construction and heat protection together with heat insulating properties confirmed in practice. By utilizing their effect spectrum, it is possible to apply fluid ceramics to textile substrate. Polymer materials application fields for technical uses are constantly increasing in number.
The requirement for textile materials with functional properties like thermal insulation, dirt resistance, electrical conductivity, and insensitivity to contact heat for example is consequently becoming every more frequent.
A high performance coating system, which protects crew and materials from high level of solar radiation and extreme cold in the cosmos, has been developed by NASA. This pioneering “fluid ceramic tile” development has proved itself over some 10 years as a fluid ceramic material for thermoceramic construction and heat protection in all climate zones.
The basic for fluid ceramics is formed by a dispersion of special acrylic resin, in the tile-form vacuumised ceramic silicon microbodies (ceramic bubbles) of which energy is significantly throttled. These microscopic ceramic hollow bodies operate on the physical vacuum and reflection principle, representing the intelligent and highly effective combination of two natural laws in the form of an applicable coating.
The material composition of the dispersion coating 9formultion for adhesives, filling agents, pigments and the exclusive ceramic bubble state) can be tuned to each other in conjunction with the bubble partial vacuum in such a way that new and more advantageous characteristic features are produced. The following are particularly included here.
- The far-reaching effect of the technical and physical causes of “heat loss’ (throttling of heat exchange by the ceramic bubble vacuum)
- Extreme sunlight reflection
- Chemical resistance of the partially ceramic thin layer
- Soiling tendency reduction due to the “rough” coating surface.
Smart Textiles or the Hi-performance Textiles are on the way commercial manufacturing. Yet lot of research has to be done on it. European countries multiplexed with Japan are ahead in terms of research & development with Smart Textiles. The life of a human being can be comfortable & safe in the extreme conditions also with smart fabrics. Now the Indian Engineers & the manufactures can look forward in developing & manufacturing such type of products.