by Jutta Stehr and Jürgen Vogel, Oerlikon Textile GmbH &
Co. KG
February 2009, Remscheid - 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).
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