by Jutta Stehr and Jürgen Vogel, Oerlikon Textile GmbH & Co. KG

Industrial textiles are the great white hope of the classical textile nations following China’s ascent to the position as the world’s largest apparel manufacturer. They are the innovation drivers for many small and medium-sized companies throughout the world.

Industrial textiles fill those areas of application that nobody had even considered 10 or even just 5 years ago. All in all, they are therefore an important reason that the ancient craft of textiles is still very much alive and active.

The field of industrial textiles comprises such diverse products as fishing nets and sacks, protective clothing and sails, vehicle tarpaulins and artificial skin or more commodity products like tarpaulins, safety-belts, conveyor / transmission belts, hoses, ropes, nets and tire-cord.

One area enjoying increasing popularity of late is geotextiles. One reason for this is advancing global industrialization, which would be inconceivable without the expansion of local infrastructures, and in particular roads. Large countries such as India, Russia and China are already carrying out, or plan to do so, major projects for improving their infrastructures, with the consequence that the geotextiles sector can look forward to a promising future.

Geotextiles are permeable fabrics (for example, jute and coconut) and synthetic fabrics (geosynthetics). They have the ability to separate, drain, filter, reinforce, seal and protect against erosion.” [1]

In industrialized nations, the use of geotextiles in road construction has been standard for several decades. In 1926, engineers started using cotton fabrics for strengthening sidewalks in the US. In 1960, needle punched nonwoven fabrics were first used in the US to strengthen roads. [2]

Today, there are various customized products available for the most varied applications, made from both manmade and natural fibers. One of these highly specialized products is geogrids, for example woven or non-woven and coated structures made from high-modulus polyester filaments. Geogrids are used to improve the stability and strength of soft, poorly load-bearing ground and slopes both for asphalt roads and unsupported construction sites and forest paths. Bridging critical points using geogrids is often less expensive and more durable than conventional measures such as replacing the soil or installing stabilizing pylons.

Stronger with Industrial Textiles

Furthermore, geogrids can be used for reinforcing dams and embankments in road and railway construction. Geogrids are gentle of resources as they permit the building of stable, precipitous embankments. At the same time, they are durable as they generally have a lifecycle of several decades.

The starting product for geogrids is industrial polyester yarns with medium titers of between 2000 and 3000 denier. As they need to be able to absorb high tensile forces, in other words stretch only minimally when subjected to loads, the multifilaments must have a high degree of dimensional stability, in other words a high modulus of elasticity.

The yarns are plied into bundles and woven or made into wide-meshed grids using warp-knitting technology. The mesh width varies depending on the requirement, but lies between 15 and 30 mm in the case of most commercial geogrids. In sandy grounds, this open, tensile structure is interlaced with the ground or the fill, hence increasing the load bearing capacity.

In a final step, the polyester grid is coated. A PVC mantle provides grids with stability and long-term protection against mechanical damage and aggressive soils. For asphalt surfacing applications, the coating reinforces the adhesion of the geogrids between the layers of asphalt by means of a bitumen emulsion.

The end applications for geotextiles demand the highest quality of the individual links within this process chain. The, to date, parallel and completely independently-existing production processes of yarn manufacturers and geotextile producers, sacrifices huge potential in terms of quality and margins. Integrated production – from the raw material to the finished product, not available to date – provides the perfect solution for this market niche.

Total solutions for Industrial Yarns

Oerlikon Barmag Engineering is world premiering its complete system for geogrids. Starting with solid state postcondensation (SSP) and its spinning plants all the way through to the coating machine, the global market leader for textile and industrial filament solutions spinning systems offers manmade fiber solutions from a single source.

One example for the solutions offered from Oerlikon Barmag is our heavy denier and super heavy denier machine concept which is designed to produce up to dtex 13,300 per winding position which for the time being is not covered by any other machine/technology supplier.

These lines can produce such deniers as dtex 2,200, 3,300, 4,400 and 6,600. Beside the primary application in the geotextile or geogrid reinforcement, the yarn is also used for lifting slings, ropes, etc. Such applications mainly require high-tenacities and adhesive finishes. One of the main advantages is that such heavy deniers can be simultaneously produced on the spin-drawing winding machine without later plying in a further, downstream process.

The depicted process (HT/LS 7) represents the super-heavy denier machine concept for the production of up to dtex 13,300 per winding position. This machine is equipped with one 4-end winder (ACW 4l-1200/4) per position featuring a package stroke (width) of 250 mm. With this machine concept, 4 times dtex, 1,670-3,300 or 2 times dtex 6,600 per winding position can be produced.

By adding another 4-end winder (HT/ LS 8), it is possible to produce 8 times dtex 1,100 and even 1,670 of conventional high-tenacity products in order to utilize the full extrusion and spinning capacity of this machine design.

A general, super-heavy denier machine consists of four winding positions in the smallest of spaces and delivers a nominal annual production capacity of approx. 8,000 tons. Therefore, such machines guarantee the lowest conversion costs in connection with an extremely economical investment.

In order to meet the high drawing and shrinkage forces needed for these products, this machine is equipped with Oerlikon Barmag’s latest godet development, the HFpower (HFp) godet.

Power godets for high-denier Industrial Yarns

The latest development of the HF godet series, the HFp godet, combines an extremely high drawing force of 320 N and a withholding force of 5,000 N with a length of 535 mm and a diameter of 250mm. Such special technical features are essential for the production of high denier ranges such as 4 times dtex, 3,300 or dtex 13,300 total.

Oerlikon Barmag has recently developed highly-effective components and aggregates such as extruders, mixers, spinning systems godets and winders which all play an important role in the production of top quality industrial yarns. As a result of the combination of these components and the expertise in polymer and yarn manufacturing, these machines meet both current demands and those of the future. In this way, manufacturers of industrial yarns can produce these yarns on a reliable machine, at a high and consistent quality level, with very good efficiency, at low noise levels and with low energy consumptions.

The most recent technologies with their multi-end layout as well as extremely high per-unit production capacities lower both the per-thread investment and the per-kg operating costs of produced yarn. When comparing, for example, dtex 6,600 with dtex 13,300 production capacities per position, a 100% higher production capacity can be achieved with just an approx. 30% higher investment per position.

Due to higher production capacity per position, the operating costs decrease by up to 20-30%, which ultimately provides a competitive edge in the market. More than 300 Industrial Yarn positions only sold in China since 2003 show that Oerlikon Barmag technologies meet the market demands and inspire our customers’ success.

[1]          Wikipedia: www.wikipedia.de

[1]          Wikipedia: www.wikipedia.de

[2]          E. Schmalz, P. Böttcher, “Märkte und Einsatzgebiete von Geotextilien aus synthetischen Fasern und Naturfasern”, Sächsisches Textilforschungsinstitut e.V.

About Oerlikon

Oerlikon (SWX: OERL) is one of the world's most successful high-tech industrial groups specializing in machine and plant engineering. The company is a leader in the field of industrial solutions and innovative technologies for textile manufacture, thin-film solar and thin-film coating, drive, precision and vacuum systems. With roots in Switzerland and a long tradition stretching back 100 years, Oerlikon is a global player with a workforce of more than 19,000 at 170 locations in 35 different countries. The company’s sales amounted to CHF 5.6 billion and it ranks either first or second in the respective global markets. In 2007, approx. 5 per cent of the turnover was invested in research and development (CHF 274 million).

Advertisement