The Modern Era of Technical Textiles
Classification, application, methods of processing, and finishing of technical textiles
The technical textiles supply chain is a long and complex one, stretching from the manufacturers of polymers for technical fibers, coating, and specialty membranes through to the converters and fabricators who incorporate technical textiles into finished products or use them as an essential part of their industrial operations.
Technical textiles are generally recognized to be one of the most dynamic and promising areas for the future of the textiles industry. Technical textiles are textile material and products manufactured primarily for their performance and functional properties rather than aesthetic or decorative purpose. Aesthetic properties are not much important for the Technical Textiles.
Although ‘technical’ textiles have attracted considerable attention, the use of fibres, yarns and fabrics for applications other than clothing and furnishing is not a new phenomenon. Nor is it exclusively linked to the emergence of modern artificial fibres and textiles. Natural fibres such as cotton, flax, jute and sisal have been used for centuries (and still are used) in applications ranging from tents and tarpaulins to ropes, sailcloth and sacking. There is evidence of woven fabrics and meshes being used in Roman times and before to stabilise marshy ground for road building – early examples of what would now be termed geotextiles and geogrids.
What is relatively new is a growing recognition of the economic and strategic potential of such textiles to the fibre and fabric manufacturing and processing industries of industrial and industrialising countries alike. In some of the most developed markets, technical products (broadly defined) already account for as much as 50% of all textile manufacturing activity and output. The technical textiles supply chain is a long and complex one, stretching from the manufacturers of polymers for technical fibres, coating and speciality membranes through to the converters and fabricators who incorporate technical textiles into finished products or use them as an essential part of their industrial operations.The economic scope and importance of technical textiles extends far beyond the textile industry itself and has an impact upon just about every sphere of human economic and social activity.
And yet this dynamic sector of the textile industry has not proved entirely immune to the effects of economic recession, of product and market maturity, and of growing global competition which are all too well known in the more traditional sectors of clothing and furnishings. There are no easy paths to success and manufacturers and converters still face the challenge of making economic returns commensurate with the risks involved in operating in new and complex markets. If anything, the constant need to develop fresh products and applications, invest in new processes and equipment, and market to an increasingly diverse range of customers, is more demanding and costly than ever Technical textiles have never been a single coherent industry sector and market segment.
It is developing in many different directions with varying speeds and levels of success. There is continual erosion of the barriers between traditional definitions of textiles and other ‘flexible engineering’ materials such as paper and plastics, films and membranes, metals, glass and ceramics. What most participants have in common are many of the basic textile skills of manipulating fibres, fabrics and finishing techniques as well as an understanding of how all these interact and perform in different combinations and environments. Beyond that, much of the technology and expertise associated with the industry resides in an understanding of the needs and dynamics of many very different end-use and market sectors. It is here that the new dividing lines within the industry are emerging. An appreciation of the development and potential of technical textile markets therefore starts with some clarification of the evolving terminology and definitions of scope of the industry and its markets.
Technical or industrial textiles: what’s in a name?
For many years, the term ‘industrial textiles’ was widely used to encompass all textile products other than those intended for apparel, household and furnishing end-uses. This usage has seemed increasingly inappropriate in the face of developing applications of textiles for medical, hygiene, sporting, transportation, construction, agricultural and many other clearly non-industrial purposes. Industrial textiles are now more often viewed as a subgroup of a wider category of technical textiles, referring specifically to those textile products used in the course of manufacturing operations (such as filters, machine clothing, conveyor belts, abrasive substrates etc.) or which are incorporated into other industrial products (such as electrical components and cables, flexible seals and diaphragms, or acoustic and thermal insulation for domestic and industrial appliances).
If this revised definition of industrial textiles is still far from satisfactory, then the problems of finding a coherent and universally acceptable description and classification of the scope of technical textiles are even greater. Several schemes have been proposed. For example, the leading international trade exhibition for technical textiles, Techtextil (organised biennially since the late 1980s by Messe Frankfurt in Germany and also in Osaka, Japan), defines 12 main application areas (of which textiles for industrial applications represent only one group):
- Agrotech: agriculture, aquaculture, horticulture and forestry
- Buildtech: building and construction
- Clothtech: technical components of footwear and clothing
- Geotech: geotextiles and civil engineering
- Hometech: technical components of furniture, household textiles and floorcoverings
- Indutech: filtration, conveying, cleaning and other industrial uses
- Medtech: hygiene and medical
- Mobiltech: automobiles, shipping, railways and aerospace
- Oekotech: environmental protection
- Packtech: packaging
- Protech: personal and property protection
- Sporttech: sport and property protection
The search for an all embracing term to describe these textiles is not confined to the words ‘technical’ and ‘industrial’. Terms such as performance textiles, functional textiles, engineered textiles and high-tech textiles are also all used in various contexts, sometimes with a relatively specific meaning (performance textiles are frequently used to describe the fabrics used in activity clothing), but more often with little or no precise significance.
Classification of Technical Textiles
Technical textiles can be divided into many categories, depending on their end use. The classification developed by Techtextil, Messe Frankfurt is widely used. The classifications and its applications are shown in Fig-1
Textiles used in Agriculture are termed as agro textiles. They are used for crop protection, fertilisation, … The essential properties required are strength, elongation, stiffness, and bio-degradation, resistance to sunlight and resistance to toxic environment. All these properties help with the growth and harvesting of crops and other foodstuffs. There is a growing interest in using materials which gradually degrade (biodegradables).
Buildtech (Construction Textiles)
Textiles used in construction – concrete reinforcement, façade foundation systems, interior construction, insulations, proofing materials, air conditioning, noise prevention, visual protection, protection against the sun, building safety.
An interesting and astethic appealing application is the use of textile membranes for roof construction. This area is also referred to as textile architecture. PVC coated high tenacity PES, teflon coated glass fibre fabrics or silicone coated PES are used for their low creep properties. Splendid examples of such construction are found in football stadia, airports and hotels.
Clothtech (Clothing Textiles)
Technical textiles for clothing applications.
These are used in reinforcement of embankments or in constructional work. The fabrics in geo textiles are permeable fabrics and are used with soils having ability to separate, filter, protect or drain. The application areas include civil engineering, earth and road construction, dam engineering, soil sealing and in drainage systems. The fabric used in it must have good strength, durability, low moisture absorption and thickness. Mostly nonwoven and woven fabrics are used in it. Synthetic fibers like glass, polypropylene and acrylic fibers are used to prevent cracking of the concrete, plastic and other building materials. Polypropylene and polyester are used in geo textiles and dry/liquid filtration due to their compatibility.
Hometech (Domestic Textiles)
Textiles used in a domestic environment – interior decoration and furniture, carpeting, protection against the sun, cushion materials, fireproofing, floor and wall coverings, textile reinforced structures/fittings.
In the contract market such as for large area buildings, ships, caravans, busses, fire retardant materials are used. Fire retardant properties are obtained either through the use of inherent fire retardant fibres such as modacryl or through the application of a coating with fire retardant additives (bromide of phosporus compounds).
Indutech (Industrial Textiles)
Textiles used for chemical and electrical applications and textiles related to mechanical engineering. Silk-screen printing, filtration, plasma screens, propulsion technology, lifting/conveying equipment, sound-proofing elements, melting processes, roller covers, grinding technology, insulations, seals, fuel cell.
Medtex (Medical textiles)
These are commonly used in bandages and sutures (stitching the wounds). Not all textile fibers can be used here, because their performances depend upon interaction with the cells and different fluids produce by the body. Sutures and wound dressing uses fibers like silk and other synthetic fibers. Hollow synthetic fibers are used with nano or very small particles are used for the delivery of drugs to any specific part of the body to prevent over dosage. Cotton, silk polyester, polyamide are also used in medical applications.
Medical textiles also cover surgical gowns and drapes. There are two classes of materials: reusables and non-wovens. Reusable are either PES or PES-cotton woven materials or laminates. Also non-woven materials are used in the operating theater.High performance non-wovens are usually laminated with a plastic foil in order to provide for sufficient barrier properties to reduce wound infection.
Mobiltech (Textiles used in transport)
These textiles are used in the construction of automobiles, railways, ships, aircraft and spacecraft. Examples are Truck covers (PVC coated PES fabrics), car trunck coverings (often needle felts), seat covers (knitted materials), seat belts, non- wovens for cabin air filtration (also covered in indutech), airbags, parachutes, boats (inflatable), air ballons.
Oekotech or Ecotech (Environmentally-friendly textiles)
New applications for textiles in environmental protection applications – floor sealing, erosion protection, air cleaning, prevention of water pollution, water cleaning, waste treatment/recycling, depositing area construction, product extraction, domestic water sewerage plants.
Packtech (Packaging textiles)
Packaging, silos, containers, bags, canvas covers, marquee tents.
Protech (Protective textiles)
Protection against heat and radiation for firefighter clothing, against molten metals for welders, for bulletproof jackets, etc, all these things are obtained by usage of technical textiles with high-performance fibers. In bulletproof jackets, special fiber aramid is used which have high tenacity, high thermal resistance, and low shrinkage. Glass fiber is also used in fireproof jackets due to its high strength, chemical, and flame resistance. Protective clothing is also used by astronauts when they go into space. It was used by the astronauts when they went on the moon, their suits were covered with special chemicals including lead to protect them from the suns heat, their suit was not only made from special fibers but their airship was also lined with special fabric.
Sporttech (Sports textiles)
Shoes, sports equipment, flying and sailing sports, climbing, angling, cycling, winter and summer sports, indoor sportswear, technical jersey fabrics.
Specific areas of application of Technical Textiles
For industrial applications and in power transmission, technical textiles are used in conveyor belts. Carcass is a fabric inside the conveyor belt, which is responsible for the strength and stretch properties of the belt. This carcass is made with layers of woven fabrics bonded together.
Electronics in textiles
It has been heard that soon textiles will be merged with electronics in all areas. In future wearable computers would be launched, these will not be like advance wrist watches etc, they will contain IC s in fabric to develop fabric keyboards and other wearable computer devices. These types of products are known as Interactive electronic textiles (IET). Research to support IET development is being conducted in many universities. Growing consumer interest in mobile, electronic devises will initiate the demand for IET products.