Wednesday 16 April 2003

Techtextil 2003: Frankfurt Germany: 7-10th April

Technical textiles is one of the few growth sectors in the West’s textile industry, and within technical textiles, the nonwoven sector is the most dynamic. The artificial boundaries between nonwovens and textiles created for trade association purposes do not exist in the real world. The TechTextil organisation therefore continues to target a nonwoven audience, and INDA has recently commenced attracting Technical Textiles producers to its events.

This conference and exhibition comprised three simultaneous sessions of technical papers, mainly originating from German technical institutes and mainly in German. The summaries here are from the papers attended, and from some of the conversations at the exhibition. All the papers on the conference proceedings CD are listed in the appendix

Key Points

  • Many of the papers presented were related to funding from those EU and national bodies keen to help the ailing European textile industry switch into technical products.
  • Intelligent textiles, textiles incorporating electronics, nanotechnology and advanced composites provided the main themes.
  • Progress claimed with computer simulation of polyester nonwovens for sound absorption suggests simulation of absorbent waddings may soon be possible.
  • A web-linker allows the production of needlefelts with hollow channels which can be filled with powders, e.g. superabsorbents.
  • A process for polymerisation of OMCTS onto cotton in plasma in a helium atmosphere develops full hydrophobicity and a soft slippery surface.
  • Shape-memory polymers have been used to develop a breathable barrier film whose water vapour permeability increases by a factor of five between 10 0C and 36 0C.
  • A new nonwoven wipe fabric has a rough side with coloured heavy-denier synthetic fibres apparently sprayed on to it. They say it simulates a recent Kimberly Clark product.
  • A lyocell fibre filled with up to 50% ion exchange resin for water purification and, after pre-loading, for controlled release, has been developed.
  • Disposable femcare now has 54% of the Chinese market (35 billion units/year)

New Perspectives

J A Beckmann of the Confederation of the German Textile and Fashion Industry opened the 12 th Techtextil symposium:-
• The 880 exhibitors represented a quadrupling of numbers present at the first event in 1986.
• Technical textiles (defined to include nonwovens) accounted for 40% of the German textile industry.
• 90% of the German textile industry was made up of small/medium size companies employing less than 250 people.
• The most innovative segments were automotive (composites), construction (composites, including fibre and textile reinforcement of concrete), health care (disposables and reusables for OR and wound-care) and functional clothing (especially garments with built in microelectronics to monitor vital functions)

Mr Beckmann called for closer co-operation between the textile and microelectronics industries and for more R&D. With the preponderance of small companies, collaborative projects were the key, and much improved communications and information sharing throughout the textile production chain were required. This should happen not only at the national level, because the 6 th EU Research Framework Programme has just started and offers new possibilities for collaboration on an EU-wide scale.

Mr Beckmann saw textile industry survival requiring change into a “cross-sectorial knowledge-based industry more oriented to the needs of the users”. He also saw the need for technical-textiles producers to work more closely with the other high-technology industries such as electronics.

Intelligent Funding?

Hervé Péro, the Director General of Research at the European Commission ( Brussels ) discussed how the 6 th EU Research Framework programme (6FP) would help to improve the competitiveness of the European Technical Textiles industry.
• Under the 5 th programme (1999-2002) 41M€ was provided to fund 37 projects directly linked to textiles.
• There were 26 European technical centers and universities with specialist technical textiles departments.
• These technical centres were not sufficiently well-known outside their national boundaries, so the “Networks of Excellence” funding within 6FP would better integrate them and would attract more industrial support.
• 6FP was based on 3 political pillars:
• The “ Lisbon ” (2000) objective: EU to become the world's most dynamic and competitive knowledge-based economy within 10 years.
• The “Göteborg” (2001) objective putting sustainable development at the top of the agenda of all EU activities.
• The “European Research Area” objective requiring 3% of GDP to be spent on R&D by 2010. (c.f. 1.9% in 2002).

Mr Péro did not specify exactly how much funding would be available for technical textiles from 6FP but thought it would come out of the 1.3Bn€ allocation for “materials, production and nanotechnology”. It would target the SME's (small and medium size enterprises) and would be used to promote real breakthroughs only: not incremental research.

He saw the need for large and complex networks in which companies would share research knowledge while continuing to compete in the market place. See also:

Intelligent Textiles

J Berger of Technologiezentrum Informationstechnik GmbH, Teltow (D) foresaw technical textiles offering new functions:
• Displays integrated into wall and floor textiles could act as orientation/information aids. (A Woven fabric has a similar structure to a plasma display screen. With the right yarns, LED's at warp-weft intersections could be made to light-up when voltages were applied to those yarns passing through the intersection.)
• Sensors integrated into textiles could monitor functions of buildings and the movements of people in buildings.
• Electronics and sensors in textiles could be supplied with power by the textile: e.g. from thermal gradients, light or even from the mechanical energy constantly generated by walking on floor covering. (Piezo-electric carpets)
• Intelligent packaging could monitor transportation routes and improve logistics recording e.g. recording the thermal and humidity history of food during shipping.
• A smart bandage could screen for bacteria or viruses in a wound, and signal the need for antibiotics.
• Landfill covers could monitor temperature and gas leakage using “meander-line fibre-optics”.

Intelligent Networking?

Dr Michael Jarrigeon, General Secretary of R2ITH (Industrial Research and Innovation in Textiles and Clothing) described the objectives of this French network:

• To stimulate innovation of new products, processes and services
• To stimulate and consolidate co-operation between all parts of the textile supply chain.
• To provide direction and strategy to public authorities allowing them to identify the real priorities.

Their priorities were:
• Integration of the supply chain via IT.
• Optimisation of material and machinery.
• Developing new technologies for design, production and marketing.
• Functionalisation of the products using active, interactive, and “smart” materials.
• Knowledge management
• Sustainable development.

The network comprised:
• 8 Centres of excellence in the French regions. (Nord-Pas de Calais has the nonwovens center of excellence)
• 8 Regional steering committees.
• A “national orientation committee”.

Each regional committee comprises 15-20 people; industrialists, service providers and public authorities tasked with promoting new projects and guaranteeing inter-area co-operation. The national orientation committee has 50 similar members plus unions and “qualified people” and is tasked with defining strategy, evaluating projects and co-ordination of the whole network.

Of the 16 projects submitted in 2002, 9 have approval.

R2ITH has a grant of 5M€ from the French Industry Ministry.

The Latest Innovations

Prof. Roshan Shishoo observed that cost reduction pressures on man-made fibres had led to R&D being curtailed and production moving to developing countries. The developed countries' share of man-made fibre production had fallen from 79% in 1970 to 26% in 2003. Inevitably, reduced innovation was a consequence, but he thought the following were nevertheless notable:
• Bicomponent staple fibres and filament yarns, the latter being fusible into rigid structures after weaving or knitting.
• Exothermic bicomponents e.g. Thermotron from Unitika, a Nylon sheath on a core containing zirconium carbide micro-particles. “Masonic N” (Kanebo) and “Lonwave” (Kuraray) were similar.
• Shape-memory polymers, i.e. laminates with layers of differing thermal shrinkage which bulk up on heating.
• Electrospinning of nanofibres.
• Biomimetics: simulating natural structures e.g. spider silk and lotus-leaf surface.
• Atmospheric plasma for polymerisation of new functionalities onto fabric surfaces.
• Nonwovens to replace PU foam.

Dr Roshan Shishoo

Supporting SME's

Mr R Junker of the German Ministry for R&D felt that the Small and Medium –sized Enterprises had great innovative capacity but found it hard to raise the funds to research and commercialise new ideas. The 6FP described earlier by Mr. Péro had a “thematic priority” requiring 15% of the funds to be used to promote participation by SME's. In addition:
• SME's will continue to receive CRAFT (Co-operative Research Action for Technology) funding to encourage them to use relevant Research Institutes.
• EUREKA is another International funding instrument providing advice an support in launching EU R&D projects and financing collaborations.

At the national level, the Economics Ministry provides:
• Start-up funding for new technology-based companies
• Funding to promote the development of innovation networks.
• Funding to promote structural renewal on the basis of advanced technologies (“ZuTech”)
• Help to start-up companies to file their first patent.

Examples of recent successes of such support for technical textile SME's were:
• New wicking drainage systems for landfills
• Lightweight textile composites for auto-interior use.
• Fiber reinforced thermoplastics for auto-body parts
• 3-D sewing systems
• Plasma treatment of textiles
• Electrically heated rugs for low-temperature heating.
• Wound-dressings which release therapeutic agents
• A transdermal collector system for drugs and their metabolites
• OR barrier fabrics
• Biotechnological modification of natural fibres

For 2004 the Ministry hopes to fund projects under an “Activity-based sustainability concept” heading. The audience was implored to contribute numerous ideas for projects to use up these funds.

Unfortunately no questions were possible and some confusion remained as to whether “success” referred to the Ministry managing to give away some money to start the project, or the project itself turning a profit.

Ion-Exchange Lyocell

Reiner Büttner of TITK Germany described their ion exchange fiber based on adding finely ground commercially available resins (styrene-divinylbenzene and acrylo divinylbenzene copolymers) to lyocell dope prior to spinning. The filled-fibre containing 50% by weight of resin had a tenacity of 10cn/tex and this was felt to be the limit of dope spinnability. If the fibre was to be carded then a 33% filling would be the practical maximum.

Applications in water purification and medicine were envisaged:
• The fibre would reduce the copper content of water from 110 to 10 micrograms/litre in 20 minutes, and the lead content from 110 to 40 in 60 minutes.
• Nitrate removal from 80 micrograms to 10 micrograms/l occurred in 4 minutes with the appropriate resin.
• Both anionic and cationic exchangers could be added to the same fibre.
• 150 mgms of the fibre removes temporary hardness from water improving the taste and clarity of a cup of tea or coffee.
• Pre-loading the resins with metals allows their controlled release into clean fluids. (e.g silver, copper or mercury for biocidal use.)
• Ionic pharmaceuticals can be reversibly adsorbed on the fibre allowing controlled release. (e.g. of nicotine)
• The very high surface area allows the acceleration of catalytic processes.

Mr Büttner confirmed that they had also added 50% ground superabsorbent to make a superabsorbent fibre.

NAPCO Technology: 3d needling

Mr P Poillet of Laroche SA described how the 3d web-linker developed in conjunction with STFI Chemnitz (and supported by Germany 's Ministry of Economics) could produce fibrous “honeycomb” structures in a single operation.

Two lightly bonded needlefelts made of fibres sufficiently long to bridge the gap between the layer are needled together over spacer-bars which hold the layers apart. The resulting product, 12mm thick at 450 gsm had cylindrical air spaces in the MD. If the spacers were hollow, they could be fed with powders allowing a composite structure to emerge.

The machine could be made up to 4.5 m wide, could link many different types of textile product and create composites up to 25mm thick (two layers) or 50mm thick (3 layers). The spaces could be empty or filled with wires, hollow tubes, granulates, powders, foams, recycled fibres. In one example an 8000 gsm product comprised polyester webs filled with cement for a special construction composite.

The list of applications provided did not mention any disposable products, but the system appears to have potential to wick fluids or encapsulate superabsorbents in several novel ways.

12m/min was the quoted maximum production speed.

Extrusion Coating

Bengt Hagström of IFP Research ( Sweden ) has studied extrusion coating a nylon or PET woven fabric.

The T-peel test of adhesion was used (EN ISO 2411.2000) to investigate the effects of Melt temperature, Extrusion speed, Line speed, Nip Pressure and Pressure roll temperature when coating over a range from 60-200 gsm (55-180 micron) with PP, PE and various modified polymers.

The results of the analysis of variance:
• Line speed has the largest effect on adhesion, followed by coating thickness.
• Lower viscosity coats give improved adhesion by greater fabric penetration.
• Slower cooling rates give better adhesion via deeper penetration of the coat into the fabric.
• Unmodified polyolefins show pure mechanical adhesion, while the modified resins (Orevac and Hytrel) show chemical interaction with the substrate.
• The regression equations work well predictively.
• Heat treatment above the MP of the coat improves adhesion (!)

Plasma polymerisation under Helium

Tony Herbert of Dow Corning ( Ireland ) explained plasma treatment as developed by Plasma Solutions – now part of DC.

By using vertical electrodes the operation can be carried out in a helium atmosphere with minimal helium loss and avoidance of oxidative reactions that limit the usefulness of corona treatments. A wide range of polymer precursors can be injected directly into the helium glow discharge to get soft polymerisation onto the fabric. (see Patent WO 02/28548).

Alkenes and acrylates polymerise by free-radical mechanisms while cyclic siloxanes undergo ring-opening polymerisation. The latter allow hydrophobic surfaces with slippery soft textures to be coated onto otherwise hydrophilic materials. Octa-methyl cyclo tetra siloxane has been used under helium to give cotton total hydrophobicity. However in the presence of oxygen, the plasma breaks it down into silicates which increase hydrophilicity.

Also for hydrophilicity, acrylic acid has been polymerised onto polypropylene to give it an absorbent and reactive surface.

Heptadecafluorodecene and other fluoro compounds have been polymerised onto fabrics to confer oleophobicity.

Other “polymer precursors” mentioned were:
• Colloidal metals for optical or conductivity enhancement
• Thiophene or Pyrrole for conductivity
• Mixed monomers for copolymer coatings and pH control.

The system allows high deposition rates and hence high productivity in a true reel-to-reel treatment under ambient conditions.

A New Natural Polymer: PTP®

P Rumeau of the French institute of clothing and textiles (IFTH) introduced a development funded by the EU under its Competitive and Sustainable Growth program (Agrocomposites). PTP® is a Polymer based on Triglycerides and Polycarbonic anhydrides (EP 0836 627). Made from epoxidised vegetable oils the polymer has so far been optimised as a replacement for PU and PVC coatings used in automotive fabrics:
• 100% extensibility is obtained without need for plasticizers
• Room temperature viscosity ( Brookfield ) is similar to PVC, but falls drastically (20000 to 60 mPas) at 90 0 C.
• Knife coating using a release paper is the preferred coating method.
• The resin needs low-temperature storage if long-shelf lives are required.
• Thermal degradation commences at 240 0 C
• Polyester coated with PTP® meet the US FMVSS 302 flammability requirements.

PTP-L, a version intended to replace epoxy-resins is made by reaction with an anhydride (petrochemical-based), and is said to be very safe for workers, consumers and the environment. Comparison with conventional epoxy systems in fibreboard panels for an aeronautical application is underway. It works better with flax than carbon fiber.

Shape-Memory Polymers and PCM Films

Dr B Pause of Textile Testing and Innovation LLC (USA) reviewed the basics of shape-memory alloys and polymers and described a composite of SMP film and nonwoven for breathable barrier applications. Here the water vapour permeability increased with temperature to a maximum at normal blood temperature.

The product is intended for single-use in OR, bedding and incontinence applications. She was unable to provide details of the chemistry and structure of the film other than to say they tended to be block co-polymers with hard and soft segments. Both segments were melted during the extrusion and forming to give the “permanent” shape on cooling. Re-heating to soften just the hard segment allowed the “temporary” shape to be created. Reversion to permanent shape occurs when next heated to the Tg of the hard segment.

Transition temperatures between 10 and 60 0 C were possible with ranges of softness being possible also.

The ingredients were commercially available but their formulation and processing was protected by a patent.

A shape-memory emergency blanket was also mentioned. This was compact when cool and bulked up to provide good heat insulation when at body temperature.

In a second paper she showed how a chemical protective suit with an inner layer of Phase Change Material in a polymer film could delay the rate of heat build-up. The PCM layer kept the skin temperature below 35 0 C for twice as long (1 hour) as the garment without PCM.

New Possibilities for Building and Living

A Roye of the Textile Institute, Aachen saw smart textiles being used in the buildings of the future. Unfortunately none of the examples of high-tech intelligent structures appeared as convincing as the starting point: the old timber-framed “medieval” buildings. Here straw-reinforced clay provided the filling between the timbers. The straw not only reinforced the clay but trapped insulating air into the structure. When wet, the clay absorbed moisture and became impermeable, whereas in dry conditions it became permeable again. In response to a question he admitted that the medieval approach could become modern again - but was unlikely to attract EU funding.

Piezoelectric fibres and electroconductive polymers

Prof U Meier of EMPA, in the course of a review of bridge-building technology, mentioned load sensors based on two concepts:
• piezo-fibres which generate a small current when loaded, or which change in length when a current is applied.
• Electroactive polymer films which expand when a current is applied

Here, Strain was defined as the % increase in length of the film strip as the voltage field is applied in the thickness-direction.

Mr Meier saw their main use in feedback systems to damp wind-induced oscillations in suspension bridge cabling.

Active materials for medical textiles

F Budillon of the Institute for Textile Technology at Aachen (ITA-RWTH) described the use of biodegradable micro-spheres based on poly-DL-Lactide co-glycolid as carriers for various therapies.

The microspheres, said to cost €1000/kg were attached to a needlepunched nonwoven with PVOH for:
• Regeneration of cartilage
• Periodontal disease therapy
• Stem cells differentiation.

He then covered glaucoma stents and shape-memory polymers and alloys.

Virtual Textile Design

Dr A Weigmann of the Fraunhofer Institute for Technical and Economic Mathematics described a collaborative project involving Audi, Sandler (Nonwovens) and Faurecia (Auto-parts). This involves computer simulation of production processes and the resulting product and its properties via:
• Surface inspection linked to 3d image acquisition and analysis
• Textile, filter and glass process simulation.
• The use of “black/gray-box” techniques to fill in gaps in knowledge.

Slides purporting to illustrate computer models of spinnerettes, spunbond fibre laydown, virtual nonwovens, fluid flow through filters, and sound absorption in cars were shown. With regard to sound absorption by a polyester nonwoven headliner, fluid flow had been shown to correlate so well that sound-absorbtion measurements were no longer needed. PET fleeces could be simulated and their performance predicted (using the Acudict II software) without ever leaving the keyboard.

Sandler now use the techniques and can:
• Use in-house fluid-flow measurements (2 hrs) instead of out-sourced acoustic measurements (4 weeks).
• Predict which headliner compression rate will give the best sound absorption from just 2 prototypes.
• Understand how fibre diameter affects sound absorption.
• Support attempts to enter new markets with new acoustic requirements.

Chinese Market

Mr Xu Pu of the China Nonwoven and Technical Textiles Asscociation (CINTA) provided market data. Of the 2 million tonnes of technical textiles produced in China in 2002, nonwovens were within:
• 230,000 tonnes were medical and hygiene products
• 218,000 were synthetic leather substrates.
• 200,000 were filters including cigarette filters.
• 95,000 tonnes were geotextiles or construction fabrics.
• Within the medical/hygiene sector, disposable femcare products now had 54% of the market, amounting to some 35 billion units.
• Disposable diapers now had 4% of the market, or 2 billion units sold.

Nonwoven production in 2002 was 632,500 tonnes of which:
• 180,000 tonnes were needled
• 171,000 tonnes were spunbonded
• 120,000 tonnes were latex bonded
• 110,000 tonnes were thermal bonded
• 21,5000 tonnes were hydroentangled
• 10,000 tonnes were meltblown
• 15,000 tonnes were airlaid pulp
• 5,000 tonnes were wet laid.

The nonwovens share of technical textiles in China was 16%, up from 10.6% in 1997.

Adjustable Insulation

Ch. Eisenmann of W L Gore and Associates introduced AIRvantage™, a garment with an inflatable lining, the thickness of which can be adjusted for comfort over a wide range of temperatures.

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