All previous INDEX events have comprised the world's largest nonwovens exhibition running in parallel with the world's largest nonwovens conference. The resulting blockbuster was of course unmissable, but not without its conflicts. Conflicts for the conference delegates who had to pay a large conference attendance fee but were unable to spend enough time in the exhibition and conflicts for the exhibitors who would have attended the conference had they not been stand-bound. Nevertheless since 1973 they came in their thousands and made INDEX into EDANA's most consistently profitable event.
Recently we have seen a proliferation of conferences including several new ones from EDANA (“Outlook”, “Filtrex”, “International Nonwovens”). Maybe as a consequence, for the first time in Geneva this year, EDANA abandoned the time-honoured format and allowed the exhibition to take precedence. However they managed to do so without alienating conference lovers. Within the exhibition space there was a small area where exhibitors presented their products to anyone who cared to sit in – at no extra charge. Outside the exhibition, a lecture hall was dedicated to the first 1-day Nonwovens Research Academy , a low-cost conference comprising 12 academic papers mainly from the European Nonwovens Research centres. This Research Academy worked well and EDANA will repeat it annually or even semi-annually in the coming years.
Another organizational innovation was the “invitation-only” Nonwovens Summit, i.e. the first meeting of a Global Steering Committee set up to unify the European, American and Asian nonwovens associations (EDANA, INDA, and ANFA). Introductory words from each of the Chairmen opened the program and two “keynote speeches” dealt with the big issues facing our industry. The first of these set out the challenges clearly and concisely and was one of the best conference talks for many years.
Keynote 1: Nonwovens – The case for global partnerships
Norbert Dahlstrom, formerly a Managing Partner at Freudenberg and ex-EDANA Chairman, had been commissioned by the current Chairman – Rolf Altdorf - to consider the nonwovens industry 15 years from now and predict the key changes needed to get there. He chose 7 issues to debate, all linked by the need for partnership for successful resolution.
- Nomenclature: Like it or not, the nonwoven industry is still, as its name suggests, a subset of the textile industry and hence remains subjugated to its political and economic manoeverings. It needs to become an industry in its own right, producing an independent category of goods as an essential precondition of fair trade. All members of the nonwoven community need to empower their associations to co-operate in a truly synchronised global initiative to achieve this status.
- Identity: The diverse parentage of nonwovens (textiles, fibres, paper, plastics, leather etc) means the industry suffers a genetic birth defect leading to a vague identity and a lack of self confidence. Nonwovens need to be easily recognized in their own right and not as a child of a related industry. Once again global co-operation between the associations is needed to promote and market “Nonwovens” to the public. This will be very expensive but it must be done.
- Information: EDANA pioneered the collection and dissemination of industry production and market data. INDA followed and extended the process to forward projections to aid investment decisions. This needs to be done annually on a global basis by a partnership of the associations. Such data is key to new start-ups and related information on international standards, test methods, legislation and regulation should all be tracked and reported by the partnership.
- Education: The rapid decline of the textile industries in Europe and the USA is leading to a loss of the colleges and institutes which have been a prime source of talented people for the nonwovens industry. The remaining institutes now educate a student population derived mainly from Asia , because the nonwoven industry as a subset of textiles does not have the profile to attract talented Europeans or Americans. Points 1-3 above must be dealt with before students can perceive nonwoven as a dynamic industry capable of providing a fulfilling career.
- Raw Materials: We need to learn to live with significantly higher raw material prices in a market where the lack of price elasticity at the consumer level is legendary. A doubling of raw materials costs cannot be absorbed in such a short supply chain and ways of overcoming the difficulties this creates should become a common concern of a global partnership of the associations. European companies must have access to imported fibres and resins free of anti-dumping and other duties. Protection of the remaining inefficient European fibre industry will accelerate its decline.
- Innovation: The nonwovens industry is embarked on a strategy of diminishing returns. R&D budgets are being reduced due to the commodotisation of the major hygiene sector. Tougher market demands and increasing competition cause the large global players to misuse their enormous purchasing power to apply ruinous price pressure on their suppliers, who as a consequence can no longer afford R&D. Costly development services are now delegated upstream and supplier audits (e.g. as operated by the automotive industry) are frequently misused to acquire and disseminate proprietary knowledge. Nonwovens could be blundering into the same trap that destroyed textiles and other traditional industries. Suppliers in the west close down to be replaced by new ones in the Third World who have invested in turnkey plants free from any innovation costs. Nonwovens still has enormous innovation potential and all members of the global supply chain must co-operate unselfishly to realise it.
- Partnership: Partnerships are the way forward for both individual companies and trade associations. Genuine partnerships are distinct from the dependent supplier/customer relationships often referred to as partnerships. Unlike the latter, genuine partnerships must abide by “the most primitive rules of mutual respect and modesty as well as some basic principles of economic life”. Self-interest and rivalry must be suppressed and there must be a greater willingness to genuinely understand and respect the motives of a partner.
Mr Filipe Girao, Head of Textiles at the European Commission's Enterprise Directorate General reviewed the adjustments to strategy that were now taking place. In the past, the EC assumed that the EU would become a “Services” economy, but they had now realised that manufacturing industry was also important if only because successful Services depend on having a healthy industrial base. Textiles/Clothing (TC) manufacture had been an important part of this base and the EC now thought it should remain so. The challenges were not insignificant:
- The EC economy had been “difficult” with slow growth for 5 years.
- The Textile quota system had ended on 1/1/2005
- The enlargement of the EU meant that some relocation of TC manufacturing within the EU was now needed to improve regional employment and cohesion.
- The competitiveness of the TC sector had to be increased if it was to
survive the tide of low-cost imports from the East. EU TC industry needed:
- Improved quality and design
- More Innovation
- Move to higher value products and services
- Increased flexibility and speed-to-market.
The High Level Group report on the European TC Industry in a Quota-free Environment had been approved in June last year and in October, and the recommended actions had been published:
- Education, Training and Employment initiatives. These included Thematic Networking between Universities and using the European Social Fund to develop/regenerate “employability”
- Research and Innovation Initiatives such as “Leapfrog” which included €14M funding for a revolution in clothing production methods. Additional support (>€20M already granted) for work in technical textiles (includes nonwovens - for construction, protective clothing and medical enduses), biomaterials/implants, and “ambient intelligent technologies for new products, services and business”.
- Competitiveness issues, including an assessment of the impact of REACH on the TC industry. (REACH=Registration, Evaluation and Authorisation of Chemicals – previously reported to be costing industry €20-30billion, causing 600,000 job losses and having a “de-industrializing” effect on the EU – presumably part of the “Service Industry” strategy).
- Enforcement of Intellectual Property Rights.
- Increased co-operation with Middle-East and North African TC producers – the “Pan-Euro-Med” market.
- For 2007-13, a Structural Fund Reserve had been proposed to deal with unforeseen crises arising from the elimination of quotas. This could fund new economic activities for the unemployed and the creation of new innovation and research centres.
In conclusion, it was now the responsibility of the TC industry to take full advantage of the opportunities to modernise.
Asked by Rory Holmes, INDA's President, if the EU would drop the duty on nonwovens imported from the USA , Mr Girao said the position was publicly known, negotiations were in progress, duties were now lower than they had been, and would probably go lower still.
Research Academy Papers
Hydroentangled Biodegradable Spunbonds
Mr Wolfgang Schilde of the Sächsisches Textilforschungsinstitut – STFI (Germany) described work on webs made from PLA (Natureworks® polylactic acid), recycled PLA, PTAT (Eastar Bio® polytetramethylene adipate-co-terephthalate) and PEA (BAK® polyester amide). The webs had been produced on a Reicofil 4 pilot line similar to the one currently being installed at STFI, and bonded on their Fleissner Aquajet pilot line. The study appeared to be more a demonstration of STFI's current and future capabilities than a serious piece of research, but the following conclusions were offered:
- PLA filaments have the highest strengths peaking at 20 cn/tex at 6000 m/min air speed.
- Hydroentangled PEA and PTAT spunbonds are softer and more elastic than PLA spunbonds. As a result PLA shows significantly higher air permeability.
- Spunlacing gives stronger spunbonds than thermal calendering or needling.
- The biopolymers reach their optimum strength at lower water pressures than either polypropylene or polyester.
- “The nonwoven centre of excellence at STFI offers a unique possibility to combine the spunbonding process with other technologies”.
Vincent Gallez of Exxon/Mobil provide further information on the use of the Vistamaxx® range of elastomeric polyolefin resins in spunbond and meltblown nonwovens. These semi-crystalline co/terpolymers of PP with other alpha-olefins have lower densities than PP (~0.86 g/cc), MFR's in the 1-400 g/10mins range and melting points between 40 and 160 o C. They stretch by 100 to 1500% with 80-97% recovery and do not need drying prior to extrusion. A narrow molecular weight range gives near-Newtonian rheology and hence excellent spinnability on conventional spunbond lines. However it crystallises more slowly so the fibres are sticky and require faster quenching than PP. This means lower melt temperatures, lower output per hole, longer quench zone and lower quench temperature. Higher draw ratios will be needed to get the same deniers as PP. (2500 m/min = 2 denier).
The elastic recovery of the spunbond nonwovens is improved by calendering which anneals the fibres and causes CD shrinkage even at surface temperatures as low as 80 o C. Extensibilities of 100 to 300% show 15% hysteresis on the first stretching and this falls to 7% thereafter.
200-300 MFR resins can be melt-blown easily into highly elastic webs with good self-bonding integrity even without thermal bonding. This “stickiness” can be a problem and a water spray can be used to improve quenching and release of the web from the forming conveyor. Clearly there is no release problem if the melt-blown is the middle layer of an SMS structure. Hysteresis falls to 8% after the first stretch.
Asked about the price of Vistamaxx® resins, Mr Gallez said they would be competitive with PU and SEBS spunbonds. To produce staple fibres spinning speed would have to exceed 4000 m/min and use a long quench zone to reach 1.5 denier fibre.
Dr Frank Meister of the Thüringisches Institut für Textil- und Kunstoff-Forschung e.V. (TITK) described work carried out in conjunction with Agrolinz Melamin International (AMI) on meltblowing specially etherified melamine-formaldehyde resin granules (MER). MER has a globular molecular structure comprising a core of 30-300 triazines with reactive groups forming a skin. The globular structure means traditionally melt-spun fibres are weak, but melt blowing followed by cross-linking in a hydrochloric-acid gas/formic acid/air mixture overcomes this disadvantage. Properties can be further improved by overbonding with a melamine-formaldehyde resin and applications in flame resistant building insulation and protective clothing are envisaged.
Asked if the nonwovens were soft enough for apparel use, Dr Meister said the softness depended on denier and was good at typical melt-blow deniers. How high could the working temperature be? Above 200 o C the fibres embrittle, but they do not ignite or melt.
Sabrina Höffele of the Leeds University Nonwovens Research Group (UK) described the principles of thermal insulation and highlighted aerogels, “nanoporous” materials with a pore size smaller than the mean free path of gas molecules. These were discovered in 1931 and can be made from many metal oxides and even polymers. Hydrophobic silica beads with a diameter of around 1.2mm are the most widely used form. They are 95% air with 20 nm pores and stable up to 600 o . Their development was funded by NASA for space-suit insulation, and Aspen Aerogel Inc (USA) now make Spaceloft® fabrics for use in ski-wear. (USP 6068882)
Leeds University has filled the cavities in its Hydrospace hydroentangled nonwoven blanket with the beads and measured the thermal properties. The beads used were fully hydrophobic, 2.4mm in diameter with a bulk density of 100 kg/m 3 and a specific surface area of 700 m 2 /gm. The addition of the aerogel reduces the surface temperature of a blanket covering a 33 o C hot plate by 2.5 o C (thermal imaging method) compared with the blanket with air alone in the cavities.
Moise Vouters of the Institut Francais du Textile et de l'Habillement (IFTH – France) described a collaborative effort to develop an intumescent back coating to replace the halogenated polymeric binders which are now used to fireproof PP nonwovens used in bedding and furniture. Physiological problems with halogenated binders in the USA and stricter EC regulations motivated the work.
An intumescent system is generally composed of three active agents : an acid agent, a carbon source and a blowing agent. Several successive reactions between these agents take place during the thermal degradation of the system leading to the formation of a carboneous expanded layer, generally called char. This char reduces heat transfer from the flame to the polymer and hinders diffusion of volatiles towards the flame and oxygen towards the polymer. Here standard acrylic or polyurethane binders (an innovative carbon source), were loaded with 15% of ammonium polyphosphate and a metallic oxide catalyst. These coatings allowed the PP fabric to pass the tests for ignitability (ISO 6941) and reduced the peak of heat release in a cone calorimeter with heat flux of 30 kw/m 2 .
Keith Middleton of Eastman Chemical Co. Technology Labs. ( UK ) reviewed the uses of cellulose ester fibres, films and coatings and considered the relevance of these “high-performance biopolymer derivatives” in today's “value-added” nonwovens. Cellulose acetate, propionate or butyrate can be made by esterifying woodpulp with the respective anhydrides in the presence of a sulphuric acid catalyst. Acetate fibres are well known in cigarette filters and more recently the film version has found a growing market in protective films for LCD displays. Gas and moisture permeability is high as is hydrophilicity, these being adjustable over a wide range by altering the degree of esterification or by using finishes or plasticizers. Acetate films with varying pore structures can be made by adding different molecular weights of polyethylene glycol to the dope at a 20% add-on level. Water vapour transmission rates of up to 2700 mgs/m 2 /day were achieved.
Biodegradability is best with the acetate ester and can be improved by reducing the degree of acetylation, values below 1.9 giving products which “mineralise” in less than a week in active composting. Biocomposites for automotive use were made by blending standard acetate fibre with natural cellulosics. These demonstrated the right balance of mouldability, tensile strength and biodegradability.
Acetate is also an excellent carrier for active substances because it can be “melt spun” at low temperature or solvent spun/cast at ambient temperature. Volatile fragrances could be incorporated without loss of the “high notes”. Furthermore acetate is bondable at ambient temperatures with FDA approved solvents such as triacetin so loaded acetate fibres could be used in nonwovens to deliver personal care ingredients, cosmeceuticals and medicaments. Cellulose esters are more effective at trapping enzymes (and retaining high enzymatic activity) than the commonly used synthetics.
Dr Krishna Gupta, the Technical Director of Porous Materials Inc (USA) has been using their novel liquid extrusion porosimetry and water vapour transmission methods to characterise the pore structure of nonwovens. In the Liquid Extrusion technique, the sample is placed on a membrane whose largest pore is smaller than the smallest pore of interest in the sample. The pores of the sample and the membrane are filled with a wetting liquid and the pressure of a non-reacting gas displaces the wetting liquid from the pores in the sample and through the membrane without emptying any of the membrane pores. The volume of liquid collected through the membrane is the volume of the “through” pores. Mercury porosimetry, which requires 20 times the test pressure, adds in the volume of “blind” pores as well. Furthermore the high pressure compresses the whole sample under test, reducing the pore sizes accordingly. Pore diameter distributions from the two techniques also differ because liquid extrusion only measures the pore diameter at the narrowest point in a constricted channel whereas the mercury technique measures the widest point. Dr Gupta concluded that the liquid extrusion technique was by far the best method for characterizing the pores in a nanofibre nonwoven of the sort used in tissue culture.
PMI's Water Vapour Transmission method involves passing gas with controlled humidity (5% to 95%), temperature (ambient to 100 o C), and pressure over both sides of a fabric which divides a chamber in two. By creating a humidity differential between the inlet gases to the top and bottom surfaces of the sample and measuring the humidity of the outlet streams the WVTR through the fabric could be assessed over a range of humidity differentials. WVTR is thus obtained as a function of the average humidity of the gas streams fed above and below the sample. Temperature and pressure gradients can also be created and the WVTR behaviour of a nonwoven whose pore sizes change as it absorbs or desorbs water can be studied in all its complexity. In the nanofibre nonwoven example, WVTR was found to be linearly dependent on the average humidity of the gas used, increasing sevenfold between 30% and 60%RH.
Dr Memis Acar of Loughborough University (UK) described attempts to develop a computer model of through-air bonding using the FLUENT software and the financial support of NCRC (USA). The nonwoven web was assumed to be made of randomly distributed PE/PP bico fibres and the computations were carried out for various air inlet velocities and web porosities. To simplify the computations:
- The web was stationary.
- Porosity and permeability of the web was taken to be unaffected by melting.
- Density of the fibres was taken to be unaffected by melting.
- Temperatures of air and fibres (solid or liquid) were assumed the same.
- Thermophysical properties of the air and fibres were assumed homogeneous and isotropic.
The calculations showed it that with a web porosity of 0.9 and an air velocity of 1.5m/s at 140 o C the fibres would take 6.6 seconds to melt, this rising to 33 seconds as web porosity decreased to 0.5. If air velocity was increased to 3.0m/sec, melting time fell to 3.5 seconds.
The authors concluded that melting time can be modelled using this technique and the model has potential for improving the design of through-air bonders.
Barbara Schimanz, a Project Manager at the Sächsisches Textilforschungsinstitut – STFI ( Germany ) presented further information on the Laroche Napco “3D Needling” process which was introduced in 2003. In this process two lightly bonded needlefelts made of fibres sufficiently long to bridge the gap between the layers 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. Applications now being developed at STFI include:
- Heat protection garments where the lightweight spacer nonwovens allow more wearer comfort than conventional insulation.
- Wetness-control covers for chairs and car seats. Here the top layer of the honeycomb would be hydrophobic and the lower layer hydrophilic, wicking occurring through the vertical fibres which create the spacer channels.
- Recycling granulated automotive plastic waste. The granules are fed into the channels in the needlefelt as it is made and the whole sheet can then be cut and re-moulded to form new headliners or parcel shelves etc.
John Hagewood, Associate Director of the Nonwovens Cooperative Research Center (NCRC - USA ) reminded us that Islands-in-a-Sea bicomponent fibres can have high strength and toughness especially when the components have widely differing melting points (e.g. nylon islands in a polyethylene sea). Interestingly, during extrusion the PE skin keeps the nylon polymer hotter for longer allowing more orientation to be developed. Spunbonds made from such fibres can, after high pressure hydroentanglement and calendering to melt the polyethylene, outperform the same basis weight of woven canvas in both grab tensile and tongue tear testing. They also outperform 100% nylon spunbonds given similar treatment.
Future work will include looking at other polymer combinations, optimizating the bonding conditions, making lighterweight fabrics for other applications and exploring the coating and laminating potential.
Ningtao Mao a Research Fellow at Leeds University Nonwovens Research Group (UK) has been modelling hydroentanglement bonding from fibre properties, water-jet parameters and web structure. Bonding depends on bending of the fibres in the web and this bending relates to “hydroentanglement intensity” (HI), defined as the product of the number of “fibre segments” hit by the water jet and the bending deflection depth of these segments. Graphs of fabric tensile strength against HI were very similar to the usual plots of strength against applied energy.
Fabrics made from viscose and polypropylene respectively were assessed for permeability and bending deflection depth. A linear correlation found. Viscose deformed more easily than polypropylene and gave less permeable fabrics. However with water pressures varying from 10 to 80 bar and fibre deflections ranging from 1.5 to 4.8 millimetres it was apparent that the experiments to date were on non-commercial fabrics.
Dr Helga Thomas of the Wool Research Institute at RWTH Aachen ( Germany ) has studied the formation of nanofibre webs from wool proteins (isolated as S-sulfo-keratins) and from chitosan in pure form as well as blended with poly(ethylene oxide) and poly(vinylalcohol), respectively. In addition, the possibility of making temperature stable nanofibre webs from silica sols deriving from tertraethyl orthosilicate (TEOS) was investigated.
Why wool? Because it has proved to be a reactive adsorbent for harmful indoor-air substances such as formaldehyde so keratin nanofibre webs could be useful components in air filtration. Nanofibres were successfully produced from the low-sulphur fraction of S-sulpho keratins but the high sulphur fraction could only be converted in blend with PEO (25% of the keratin) to give 440 nm fibres.
Chitosan, a natural antimicrobial, electrosprayed rather than electrospun to give a nano-particle-fibre intermediate. It could only be converted into fibres in blend with PVA (giving 355 nm fibres) or PEO (giving 224 nm fibres) but the antimicrobial effect of the nanofibre webs was nevertheless demonstrable, both alone and after “bonding” with a Chitosan size.
Silica sols converted directly to give 630nm fibres in electrospinning but the addition of 1% ethanol to the dope caused the average diameter to fall to 234nm. The dried webs were unaffected by heating to 210 o C for 10 minutes. These webs could also be sized with Chitosan to give them antimicrobial properties.
Dr Thomas concluded that electrospinning of water soluble polymers is a powerful tool for generating functional nonwovens with very high surface area.
Selected Product Presentations
updated the situation on PLA fibre since Cargill bought Dow Chemical's share of the old CDP business. Their Blair Nebraska plant is producing about 140,000 tonnes/year of PLA resin and a further 180,000 of lactic acid. Resin can be bought from Natureworks, and the Ingeo staple fibre from FIT. Filament is produced by Antex/Radici. 65% of the resin goes to packaging, 30% to textiles and 20% to nonwovens. The main nonwoven applications are still hi-loft waddings. 70% of sales are in Japan and Europe is expected to move next. The US market is “slow”. Resin prices have fallen and are now between $1 and 80c depending on melting point. Further reductions will depend on switching to other sources of biomass, e.g.corn stover, and using less fossil fuel by using windmills to generate power for the Blair plant.
continue their strategy of acquisitions to allow them to offer a complete range of machinery to the nonwovens industry with the purchase of Kortec festooning to complement their M&J air-laying, Ason spunbonding and Autefa crosslapping operations. They now need opening/carding, hydroentanglement, thermal bonding, needlepunching, heatsetting, drying and winding technology and will be looking to buy companies or form partnerships in these technologies. To underline the size of their operation they observed that their spinning machine installations now produce 17,000 tonnes per day of fibre. Their R&D centre has 8 pilot lines (including fibre spinning) and now includes the new Nonwovens Solution Centre. However the previously announced move to a Nanoval pilot line has been shelved due to disappointing results from the trials conducted since they acquired the innovative nanofibre melt-blowing technology.
have introduced a second generation Hy-Wettable fibre with improved durability of hydrophilicity. It is being sold at the same price as the basic fibre “to allow customers a chance to innovate”. The polymer is modified by addition of polar groups. Asked how likely it was to make inroads into the viscose share of the wet-wipes market the salesman rather candidly admitted that if they could have got it out a year ago before the price rises it would have been very successful. Now it was probably too expensive. Fibervisions have also introduced 100% polyethylene staple, intended to be blended with polypropylene to improve the wipes softness.
are upgrading their Perfobond 3000 spunbond system to allow it to handle polyester by the end of 2005. Their strategy is now to supply complete nonwoven lines, including SMS which will use the Rieter Automatik Emblo® melt-blowing system. Their hydroentanglement lines (130 supplied to date) now comprise, Trutzschler – Laroche opening and blending, F.O.R triple-doffer cards, Jetlace 3000 bonding, and Perfodry 3000 drying followed by calendering and winding. The latest trend is to customize the spunlace fabric with embossed or watermarked patterns or logos. Their Isojet system is a patented way of boosting the CD strength to achieve square strength properties. Spunjet is a combination of the Perfobond and the Jetlace 3000 systems to make HE spunbonds.
were showing elastic Bicomponent spunbonds made from a thermoplastic polyurethane (TPU) core and a PP, PE or PET sheath, the latter for products that needed dyeing. The PP sheath, despite longitudinal crennelation caused by core contraction, masked the rubbery feel of the TPU, and this product has been produced commercially over a range of 25 to 300 gsm for hygiene and other industrial applications. They hope to repeat the work soon with an elastomeric PP core. The production line used is 2.3 metres wide but uses a tenter frame to stretch the formed fabric out to 5 metres wide. So far the product is thermal bonded but they intend to try hydroentanglement as well. The product as marketed by Advanced Design Concepts – a JV between BBA and Dow Chemicals - won the Index 05 award for the Best New Nonwoven for disposable enduses, and a product made from the spunbond (“Forever Fresh” Underwear) won the Best New Disposable Finished product award.