The economic significance of the technical textiles and nonwovens industries has been recognised recently by the financial world, in a report by the German-headquartered Commerzbank.
This puts the current value of technical textiles at an annual US$133 billion, representing 25 million tonnes of material, with the nonwovens industry worth a further US$26 billion a year, and with an approximate annual output of 7.6 million tonnes.
There is a vast range of performance materials that fall under the umbrella term of ‘technical textiles’, including insulation and reinforcements for the construction industries, along with geotextiles for road stabilisation and many different kinds of filter. The automotive industry is another big user of technical textiles, as tyre cords, in airbags and safety belts and in seating and interior decoration, as well as insulation. Other important sectors include furniture covers and filler materials and components for sports and leisure products such as sleeping bags and sail cloth.
Given this wide range of applications, various technologies are employed to make technical textiles.
At ITMA 2015, for example, the major manufacturers of weaving machines – including Germany’s Dornier, Italy’s Itema, Picanol of Belgium, Toyota and Tsudakoma of Japan and a number of fast-rising Chinese firms – will be demonstrating looms that have been specially engineered to deal with yarns of glass, aramid, carbon and other extremely high performing fibres.
Polypropylene yarns and tapes are generally employed for the weaving of ‘big bags’, sacks and tarpaulins, which is another significant, if often overlooked sector, particularly in China and India.
In my last blog entry, I also highlighted the fact that there is currently strong growth in the sales of multiaxial knitting machines for the production of technical fabrics employed in the reinforcement for composites.
Nonwovens, however, are made very differently in that the yarn process is omitted and the fabrics are produced directly from either fibres or polymers. Generally, those lightweight nonwovens employed for disposable end-uses such as diapers and other absorbent hygiene products are made from directly extruded polymers in the spunbond process that has more to do with the plastics industry than textiles. More durable products, such as those for filters and automotive applications, are most often made from carded staple fibres consolidated into fabrics by either mechanical, thermal or chemical processes.
Needlepunching is the mechanical method of bonding nonwovens and the latest machinery for this process is always prominent at ITMA shows.
At ITMA 2011 in Barcelona, for example, Germany’s Dilo showcased a complete nonwoven line with a width of 3.5 metres in full operation. It consisted of two bale openers, a MultiCard, a DLSC crosslapper and needleloom, with innovations including the Profiline CV1A web compensation system. A high potential for fibre savings along with low energy consumption were key characteristics of the line shown. Designed for very economic web forming and needling, it also allows for reduced maintenance and cleaning and easy operation, while being capable of speeds of up to 160 metres a minute.
Other leading manufacturers of needlepunching equipment include Andritz Nonwoven, Autefa and Trützschler, while making its debut at the last ITMA and returning this year will be China’s Ying Yang – a company that until recently was little known outside China itself but is now installing an average of over 300 full production lines every year. Ying Yang’s machines are accredited to carry the China Famous Trademark.
Machinery for recycling and the conversion of alternative natural fibres and waste products will also be well featured in Milan, from companies including Italy’s Bematic, Bombi and Cormatex, along with Laroche of France.
The production process for nonwoven wipes is different again, involving the use of hydroentanglement or spunlace systems in which the fibre webs are bonded by high pressure water jets. The pioneers of this technology are ITMA exhibitors Andritz Nonwoven and Trützschler, and both have recently been involved in the development of systems to achieve the seemingly impossible – the production of flushable nonwoven wipes that are strong enough to be manufactured, transported and perform properly, but once flushed, disintegrate entirely.
New areas of application
Although the global markets for technical textiles and nonwovens are subject to cyclical fluctuations, they continue to experience positive growth. In addition to megatrends such as the rising world population, urbanisation and increasing environmental protection, this growth is being driven mainly by the development of new areas of application and new production processes.
Commerzbank observes that technical textiles have already progressed into a large number of new areas of application in recent years and could accelerate in future, driven by various new areas of research.
One particular field is the use of fabric technologies to produce and store energy.
The use of photovoltaic technology on textile surfaces is already state-of-the-art, and the first photovoltaic fibres with a low level of efficacy are already available in the laboratory. The realisation of photosynthesis based on textile surfaces is also being developed intensively. Textile facades and roof surfaces as renewable sources for the production of energy or drinking water are now close to commercialisation, and since they mainly use natural raw materials, such products also largely function on a sustainable basis.
Another important area of R&D is nanotechnology. In general, nanostructured surfaces make it possible to transfer a number of different functionalities to textile structures. In particular, dirt and water-repellent functions – known in nature as ‘the Lotus effect’ – have been at the forefront. Textile structures, however, can also be provided with a number of other properties, such as resistance to washing and abrasion, anti-friction, electrical conductivity or magnetic protection, catalytic self-cleaning, special filtration and binding characteristics (e.g. as chemical catalysts) and the controlled release of contents such as medication.
R&D is not only focused on coating or finishing textile products, but also on the development of completely new products and applications. The most important areas of application are currently filtration, medicine and protective textiles.
The integration of the results of microelectronic and sensory R&D into textile production will also be a major area for new products and areas of application. The first stage of development was the pure integration of microelectronic or sensory components and instruments into textile products. Now work is currently focused on either equipping the fibres themselves or their coatings with electrical conductivity or sensory properties in order to enable textile electrodes or printed electronics. The primary areas of utilisation for such products are likely to be medicine, protective applications, sport and leisure and – against the background of the growing importance of electromobility – lightweight vehicle construction. In a few years’ time, completely new textile products such as textile displays, textiles with colour changing and self-cleaning functions, energy-saving surfaces, self-healing structures or reactive protective textiles could also become a reality.
Meanwhile, although three-dimensional textile structures such as spacer fabrics, padding and mesh are perhaps no longer completely new, they are still at a very early stage of development. For nonwovens production in particular, many new areas of application have opened up recently as a result of the development and introduction of spacer technologies.
This applies particularly to the areas of medical fabrics and filtration systems. The multiple layers and porosity of 3D textile gradient structures have advantages, for example, for the cultivation and development of cell structures or for the efficiency of particle separation. Experiments are being carried out using three-dimensional stitching technology in the production of preforms for composites.
Fashion and sportswear
Many of these developments are also now capturing the attention of the fashion apparel and sporting brands and retailers looking to differentiate their products. The marketing potential that comes with additional performance properties and the inclusion of new and unique textures in fabric construction is proving highly valuable to the stories brands can tell around their products.
“Technical textiles are still underestimated and that’s why we decided to take a deeper look at them,” says Commerzbank analyst Jürgen Grebe, who compiled the report for the bank.
Behind all of these developments, of course, is the latest manufacturing technology, for which ITMA remains the definitive showcase.