EDANA Filtrex 08: Cologne : 6-8th October 2008

Key Points• Fresh and waste water filtration is now the largest and fastest growing segment of the filter media market.
• The growing demand for cleaner water is attracting major new players into the water treatment market.
• H&V's Nanowave™ technology yields a filter with a wavy surface which provides half the pressure drop of the equivalent glass filter with 3 times the dust holding capacity and a higher filtration efficiency when discharged.
• Irema Filter is co-forming PP nanofibres with a standard PP meltblown to give a gradient structure which has higher capacity, lower pressure drop and longer charge retention than the usual two-layer structure.
• CamilFarr use a new form of active carbon with “Rapid Adsorption Dynamics” in an F7 filter to absorb low concentrations of pollutants quickly.
• Norafin's 420 gsm hydroentangled fabrics with a split bico microfiber surface can match the performance of a 500 gsm needlefelt with an ePTFE membrane surface.
• Europlasma use plasma to polymerise a monomer onto PP to render it permanently hydrophilic. The monomers used are secret and the process needs a vacuum.
• With air handling fans consuming 15% of all electricity consumption, the EU are expected to require energy efficiency labelling of air filters in about 3 years.
• The nanoalumina whiskers used in Ahlstrom's Dispruptor™ papers can immobilize 8 micron active carbon powder without the need for binders which can reduce efficiency. The resulting filters are excellent for cleaning up water for drinking.
• Dupont's HMT nonwoven uses direct-spun continuous nanofibers to achieve membrane-like filtration at lower pressure drop.

Keynote: Filter Media Markets

Ken Sutherland of Northdoe UK defined the filtration market to include deep-bed sand filtration, coarse porous materials, wound yarns, woven fabrics, felts, papers and nonwovens including glass and carbon materials, sintered metal and ceramic media and polymeric membranes. Strictly speaking membranes were not filters because they separated molecules by rate of diffusion, and were not intended simply to remove particulates.

His $ values were at the point of sale to the filter equipment maker or replacement user and included all industrial, commercial and residential filters, whether fitted as original equipment or sold as replacements. Data of most interest to the nonwovens industry – tonnes or square metres of roll-goods - was not available:

• The world market for filter media in 2007 was $21.7 billion.
• 38% of this was sold with the filter hardware, and 62% in the aftermarket.
• Nonwovens accounted for 27% of this and Paper (surprisingly) another 2.9%.
• Membranes were the biggest sector (35.5%) with spunmelt nonwovens (14.3%), metallics (10.4%), felts (9.9%) and constructed cartridges, i.e. filter media plus frame and end caps as in most automotive air and oil filters, at 7.1%, making up the top-five filter types.
• USA (24.4%), China (12.1%) and Japan (7.5%) were the main countries of use. China was growing much faster than the others and because of the difficulty of getting good information could already be much larger than this. (The USA had fallen from 50% a few years ago.)
• Fresh and waste water filtration (14.3%) is the largest individual sector, followed by Bulk Chemicals and Petrochemicals (13.6%), Fine Chemicals and Pharmaceuticals (9.6%), Food & Beverage (8.3%), Power Generation (7.4%), Medical and Health (6.3%) and Mining and Metals Processing (6.0%)
• The global market was growing at 5.6% annually, China at 10.1%. Water treatment was growing at 6.8%.
• Major growth drivers were:
• End user demands for cleaner and purer water and air. (“Everyone, all the major companies, are getting into water treatment”)
• Environmental regulations tightening
• Growth in China and India and other developing regions.
• “Most of the areas the World now needs to improve involve using better filtration.”

Technologically, the development of ever finer fibres, and materials with better heat/chemical resistance was leading to innovative new filters. Heat/chemical resistance was getting more important as companies tried to save energy by extracting heat from effluent: the heat exchangers now requiring pre-filters to keep them working properly.

Asked for more detail about the $ values, Mr Sutherland said the total filtration market (equipment plus media) was $44bn, and all his numbers were based on the exchange rate on July 1 st 2007.

Nanowave™

Andre Boni, Director of Marketing for Hollingsworth and Vose described their proprietary new technology to make an “extended surface synthetic media”. Nanowave™ was a development of Nanomelt™ introduced at Index in 2005, the latter having had problems due to its higher initial pressure drop, lower test dust capacity and premature blinding by fine dusts.

The unique feature of Nanowave™ was its wavy surface, and this gave the following benefits:
• Double the alpha value of conventional discharged melt-blown media (alpha=Efficiency/Pressure drop)
• Double to treble the dust holding capacity (wavy surface, like crepeing, gives twice the surface area per square metre of filter.)
• The nanofibres give a high discharged efficiency.
• The structure can also be charged for even higher efficiencies
• Wave height, density and polymer type, as well as fibre dimensions can be adjusted for specific applications.
• It is stiffer and more resistant to compression.

Initial focus is on an HVAC bag filter to meet the F5 to F9 classes of EN779. Here synthetics, usually charged and so liable to lose efficiency over time, are battling with glass fibre which is more consistent but might shed fibres. Nanowave™ gives half the pressure drop of the equivalent glass filter, with 3 times the dust holding capacity and a higher efficiency even when discharged.

Asked about price, Mr Boni said it would be a premium product, but H&V would position it competitively. It is not commercial but test quantities can be made available.

Integrating Nanofibres

Wolfgang Rupertseder, Plant Manager, Irema Filter ( Germany ) reminded us that diffusion is the main mechanism for fine particle capture, and then the particle must stick to the fibre. The force of adhesion is highest when the fibre diameter equals the particle size, and in a real world gradient filter you can see that the coarse fibres catch the big particles and the fine fibres catch the small ones. Once fibres get smaller than about half a micron, a “slip-flow effect” (the air velocity at the surface is no longer zero) occurs and this reduces the pressure drop to about 70% of that calculated using theory which works for larger fibres.

Rather than create a layered structure with nanofibres laid on top of coarser melt-blown fibres, Irema co-mingle the fibres by spraying the two types into one another before they land on the conveyor. A bulky gradient structure is obtained with the top surface being richer in nanofibres than the bottom. For some applications a third head will apply a protective microfiber layer to the top side. The heads look like conventional melt-blow heads, and the nanofibre size (0.1 to 0.5 micron claimed) is probably obtained by running the nanofibre head at very low productivity, and the whole line at low speed.

The product is commercial in automotive cabin air filters where it gives a 70% NaCl capture efficiency and longer filter life. Media for HEPA filters is under development.

Results shown were for charged media, but in response to questions Mr Rupertseder said the blend structure discharges more slowly than a layered structure. PP is the main polymer used but the process has been shown to work with PET.

Nanogate Technology

Yvonne Klattwitter, Product Manager for Nanogate ( Germany ) said their core competence was formulating products using nanomaterials and processes based on nanotechnology. Their N-Charge® coating had been designed to improve the ability of surfaces to store an electric charge and works as a dielectric which prevents discharging due to particle capture. Realising that this may have applications on fibres and fabrics, they developed Permastatic® as a spray-on or paddable water-based coating.

Nonwovens coated with Permastatic® have:
• The same permeability as untreated nonwovens. The coat is 100nm thick.
• Increased fractional filtration efficiency. Retention of submicron particles improves from 70% to 90% in vacuum cleaner bags as tested by Filz Fabric Fulda.
• Longer lasting electrostatic properties. Charge retention was up from 61% to 83% in a 5 months test. In a 2 year test 100% PP and 100% PET retained their initial charge of 3-4kV almost unchanged. (Were these fibres or films?)
• Resistance to water washing and IPA extraction

Permastatic® can be combined with other treatments to give improved cleanability, hydrophobicity or hydrophilicity, and is said to be easily incorporated into existing processes as a low-cost upgrade. Ms Klattwitter could not answer questions about cost.

Nano-pollution

Thore Bertilsson and Jörg Scharnberg of CamilFarr ( Sweden ) defined air pollution as “matter found in the atmosphere not belonging to its natural consistency, or matter found in indoor air with harmful effects on people and materials”. Examples included dust, soot, mist, fog, gases and vapours and radioactivity. They can be natural (forest fires, volcanos, dust storms) or man-made (incineration, fossil fuel combustion, factory effluent). Very small particles and gases presented particular problems. Normally polluted town air had a bimodal distribution with particle size peaks at around 0.2 and 8 microns. Modern diesel engine exhausts emitted particles below 0.3 microns and these could pass through the lungs into the bloodstream. However an F7 air filter with >50% discharged efficiency at 0.4 micron would give acceptable air quality, reducing PM10s by 87% and sub PM1s by 75%. To improve on this and get noticeably better air quality a filter meeting EN13779:2007 would be required.

Atmospheric polluting gases - NOX, SOX, NH3, HCl, VOCs – and indoor pollutants, formaldehyde from wood and carpets, ozone from photocopiers and various unpleasant odours from food and waste can only be removed by adsorbtion on active carbon, active alumina or ion exchange resins. Existing granular forms of active carbon are too slow to adsorb low concentrations to be useful in HVAC systems but an new form with Rapid Adsorption Dynamics is now available. RAD deals with really low concentrations of pollutant quickly by virtue of being a really small particle of active carbon, and it can be integrated into an F7 particle filter.

Other pollutants which are currently untreatable include CO 2 , CO, CH 4 , NO, He and Ra.

Ahlstrom Disruptor™ in Reverse Osmosis

Domingo Sanchez (R&D) of Ahlstrom Filtration (USA) replaced Rodney Komlenic, VP Business Development, to deliver the paper on the Dispruptor™ fabrics made under licence from the Argonide Corporation. Here, naturally occurring 2nm by 250nm boehmite whiskers are attached to submicron microglass fibres which can then be easily processed by Ahlstrom into wet-laid nonwovens. These nonwovens have a 2 micron average pore size and a 42,000 m 2 nanofibre surface area per square metre of nonwoven. At pH 7.2 they have a >50millivolt zeta potential which is effective for up to a micron from the whisker surface, this allowing them to capture particles below 0.5 micron electrostatically, while the large particles are retained mechanically. In some tests they have been shown to retain 6 times their own weight of contaminant. They can be used at operating temperatures above 400 o F, yet have filtration efficiencies similar to the UF/MF polymer membranes while incurring a fraction of their pressure drop. Examples of use covered products normally associated with reverse osmosis, nanofiltration, ultrafiltration and microfiltration:

• Compared with membranes having a range of pore sizes (0.025 to 1.2 microns) Disruptor™ media removed B. diminutia, MS2 virus, and an endotoxin with higher efficiency at lower pressure drop and higher flow rates.
• T4 phage was adsorbed from a concentrated solution by simply immersing Disruptor™ in the solution.
• Iron, tin, lead and copper particles, problematic in drinking water and waste from metal finishing, were all removed easily by Disruptor™. Dissolved iron was also removed.
• The nanoalumina whiskers will immobilise 8 micron powdered active carbon (PAC) powder without the need for binders which can reduce the PAC adsorption efficiency.
• The resulting Disruptor™PAC paper can remove 1gm of chlorine or iodine from water per gram of PAC.
• Disruptor™PAC successfully removed all the humic acid from drinking water spiked with 20 FTU and reduced the turbidity of the water to zero. Even standard Disruptor™ removed more of the humic acid than the tightest (0.22 micron) Millipore membrane.
• Disruptor™ remove trace amounts of organic matter from lake water at high flow rates and very low pressure drop.
• They effectively reduce water contaminants missed by GAC beds, flocculation, microfiltration and ultrafiltration processes.
• As prefilters on reverse osmosis processes, the membrane cleaning routines can be increased from monthly to six-monthly due to their ability to reduce the silt density index (SDI).
• Biofouling of membranes by proteins, lipids, carbohydrates and amino acids can be significantly reduced.

Disruptor™ nanoalumina whiskers have been used in medicine since 1926 and have FDA approval for use in human vaccines. They have now passed the NSF/ANSI standard 42 for water contact use and standard 53 for water contact and cyst reduction, USP class VI and endotoxin testing. In conclusion Ahlstrom believe this is a real breakthrough in reducing a wide range of reverse osmosis biofoulants via electroadhesion and mechanical entrapment.

Asked about the cost of the papers, Mr Sanchez simply said $20/m 2 for an average basis weight.

Microglass and Spunbond

Dr Werner Groh of Johns Manville ( Germany ) introduced their new CombiFil® Premium air filter medium made by flame-blowing 1-3 micron glass fibres between two layers of spunbond polyester. The process can be used to make filter efficiencies up to HEPA with high stiffness and pleatablility without the need for wire supports. It holds more dust at lower pressure drops and maintains a stable filtration performance over longer times than the charged synthetic media with which it competes. Specifically, an F8 Combifil®Premium filter holds more dust at a lower pressure drop than an F7 synthetic.

Price? Dr Groh said it would be ~€3/m2 or about twice the cost of a standard material. The microglass was spray bonded with phenolic resin, which also served to bond the polyesters in place.

Spunlaced for Membranes?

Victor Lorentz, Sales Manager of Norafin ( Germany ) described the versatility of their core technology, hydroentanglement, pointing out that it was capable of making filters to compete with needlefelts in all applications. Furthermore it gave filters with a more uniform pore structure over a wider range of basis weights (40-700gsm). For demanding applications, metal or glass scrims were used as reinforcement. A 320 gsm hydroentangled filter gave efficiencies comparable with a 500gsm needlefelt at a much lower pressure drop when the same fibre were used.

If splittable bicomponents were used, much finer filters could be made, but only over an 80-120 gsm range because lighter fabrics were too thin to withstand the splitting pressures, and heavier ones were too costly to split sufficiently. Because the splitting occurred mainly at the surface, a gradient structure with a membrane-like surface was obtained in a one-pass operation without the need for lamination and binders. The fibre splitting increases the filtration efficiency from 65 to 95% for 1 micron particles on 1.3 dtex fibres. If a 100 gsm “microsplit” fabric was laminated to the 320 gsm standard HE fabric the resulting filtration performance had been shown to match a 500 gsm needlefelt with an ePTFE membrane surface.

Asked about the mechanical properties of the spunlace, Mr Lorentz said they were more robust than the equivalent needlefelts and the membrane surface more durable than the ePTFE. Could such materials be used in HVAC? Yes, if the split-fibre layer was laminated to a more bulky base.

Pleatable PET for Depth Filters

Dr Ulrich Hornfleck Sales Director of Sandler AG ( Germany ) observed that carded polyester, chemically bonded in thicknesses up to 3mm can be easily pleated to make an excellent self-supporting coarse dust filter for use in filter classes from G3 to F5 depending on the fibre decitex. However the finest cardable fibre diameter (i.e. about 10 microns) prevented this construction from entering F6 and above.

A new 3-layer structure with a highloft base, an ordinary fine fibre carded polyester centre and a melt-blown polyester surface layer has been shown to maintain its pleatability, offer temperatures of up to 120 o C at constant load with 200 o C peaks, have high mechanical stability and a very high crack resistance. Air permeability and dust holding capacity was superior to F7 microglass media.

A questioner was concerned that the comparisons between microglass and such a thick polyester filter would be invalid, because the use of flat sheet test methods rather than pleated media tests would bias the conclusions in favour of the thicker material. In real filters the glass media would allow a higher pleat density.

Characterisation of Needlefelt Surfaces

Joseph Schuberth of the Vienna University of Technology ( Austria ) has developed a method for comparing the particle penetration and particle holding capacity of filter media. A light microscope and image analysis software was used to determine the surface porosity and the pore depth distribution of a range of felts. Combining these with the mean clean gas concentration and dust loading obtained from a VDI 3926 Type 2 tester, correlations between the optical and physical tests were obtained. These calibration graphs now allow the clean gas concentrations and dust holding capacities of other needelefelts to be estimated simply by using the microscope and image analysis software. The optical measurements can also be used to calculate the relative standard deviation of the pore-size and the average porosity on both clean and dust-loaded filters, and this will allow investigation of clogging mechanisms.

Engine Oil Filters

Claes Frennfelt of Volvo Powertrain ( Sweden ) underlined the importance of oil filtration in reducing the costs of operating a fleet of trucks and complying with the ever-tightening regulations on exhaust emissions. Oil lubricates, cleans and cools a truck diesel and is typically filtered in a bank of three large cartridges. Two of these operate at 60-80 litres/hour on the whole oil circuit, while the third, a finer “by-pass” filter operates at 8 litres min. The 40 liters of oil in the circuit is at 400 to 600 kPa.

Standard cellulose filters last 60,000 km while long life versions can do 100,000 km. For 150,000 km service intervals a synthetic blend filter is needed. These synthetic filter cartridges are much more expensive because they are not self-supporting. Other factors affecting oil service life are fuel quality (>500 ppm sulphur shortens the filter-life), exhaust gas recycling (reduces it by a third), biofuel use (a 30% biofuel blend halves it), and topography (hilly worse than flat). Compared with the 3 times more expensive synthetic oils, mineral oil works well up to 100,000km in normal climates. The low viscosity synthetics are needed in cold climates.

Plasma Coatings for Engine Air Filters

Marc Pauwels of Europlasma NV ( Belgium ) described how plasma could be used to polymerise a monomer onto the fibre surface to give a permanent coating. Filter media could be processed in a vacuum chamber on a roll-roll system, or complete cartridges could be processed batchwise. Hydrocarbon monomers give permanently hydrophilic coatings when treated in the presence of oxygen and fluorocarbon mixtures give oleophilic and hydrophobic coatings. The process is used to improve air filters for diesel engines by increasing the hydrophobicity of a PBT nonwoven filter so that it can pass the water decantation and repellency tests. The benefit is achieved without altering the dust holding capacity or filtration efficiency. It is also used on facemasks, air conditioner filters, battery separators and blood filters. The roll to roll process runs at 5 m/min and the current kit can take 60cm diameter rolls. Variable costs are €0.02/m 2 , said to be cheaper than a wet-chemistry approach and better for the environment. Asked what monomers were used to achieve permanent hydrophilicity on polypropylene, Mr Pauwels said this was a secret. Atmospheric plasma treatment did not work because the monomer loss proved too costly.

Predicting Filter Performance

Martin Lehmann, Head of Simulation Filter Elements at Mann and Hummel ( Germany ) said measuring the distribution of fibre diameters in a filter is the key to predicting filtration performance and Mann and Hummel had developed a new way of doing it. Using a single average diameter was clearly wrong and SEM or optical microscopes coupled with image analysis were poor. He used the new Matlab image analysis software but provided no details. Furthermore his work with cellulose filters assumed that the clearly flattened fibres in the filter were round with a diameter equivalent to their width. Asked about this, he felt the microscope “saw” the fibres as a dust particle would, so the assumption of roundness was OK. The technique could be used in QC.

Testing Single Pleats

Dr Harmut Sauter of Mahle Filtersystems ( Germany ) described the three scales of filter evaluation: micro, meso and macro where macro considers the whole filter in its housing, meso considers the filter alone and micro considers filtration at the interfibre level. Most automotive air filters are pleated so at the meso level, understanding the behaviour of a single pleat becomes fundamental to filter design. Furthermore, the single pleat lends itself to computational fluid dynamics (CFD) simulation of air velocities and hence comparisons of experimental with simulation data.

Air velocities were measured by particle image velocimetry (PIV) where the particles were too small to be separated by the filter. Static pressure measurements at one air velocity showed that the simulation technique provided roughly comparable data, the differences being attributed to the pleat changing shape under pressure. In fact in a real filter they were observed to stretch and vibrate and change the way the dust distributes itself. Maybe the use of a V shaped pleat was too simple. The N shape might represent the smallest filter element more exactly.

Classifying Air Filters

Dr Thomas Caesar, Manager Filter Technics, Freudenberg Nonwovens ( Germany ) observed that as energy prices and CO 2 emission concerns increased, the power consumption of air filters was being scrutinized. In the UK and Sweden where the data is available, 15% of all electricity consumption is by the fans used to handle air, and a third of this power was lost in pressure drops across the filters used to clean the air. So energy efficient air filters would help to save the planet and they therefore had to be classified according to their energy efficiency as well as their filtration efficiency. The target is to identify the types of filter which provide the highest possible particle removal efficiency at the lowest possible pressure drop, the complication being that both of these parameters varies with the life and dust loading of the filter.

Dr Caesar proposes the derivation of a “key energy performance” or kep number which is a function of the average efficiency from EN 779 using a 0.4 micron particle at 3400 m 3 /hr, and the average pressure drop derived from a loading of 800g of ISO A2 dust also at 3400 m 3 /hr. Kep numbers less than 1 are given “Energy Class 1” as the most efficient now possible, and kep numbers below 0.6 are given “Energy Class 5” being the least efficient. These 1 through 5 Energy Ratings would be used like refridgerator energy classifications so that filter buyers could choose the efficiency they could afford.

Asked if this was just for Freudenberg or would it become an official standard, Dr Caesar said he was working with ISO and would expect it to become an international standard in about 3 years. Freudenberg would be introducing energy efficiency labelling on their range by the end of next year. Is the market demanding this? “Basically yes”.

Nexylene PPS fibres

Dr Jens Neumann-Roderkich, Development Manager, Nexis Fibres (Germany) ran through their PPS brochure, reminding us that poly phenylene sulphide fibres offered exceptional thermal stability up to 200 o C (melting at 290 o C) and were therefore positioned, both from a performance and price viewpoint, between nylon 6 and the meta-aramids. Unlike the meta-aramids, they were melt spinnable and could be produced in crystalline and amorphous forms with differing properties. The stronger crystalline form exhibited a shrinkage of up to 8% on heating to 220 o C, and the amorphous form could be used as a stretchy binder fibre with identical thermal stability. They could be made into all forms of nonwovens, the needlefelts with 25% Nexylene woven scrim being offered as recyclable hot gas filters. There were several questions and one comment from the audience:

• The comment pointed out that this fibre could not be sold as a hot gas filter because it did not meet the required thermal stability at 250 o C.
• How did Nexylene compare with Japanese and Chinese sources of PPS? It was as good as the best Japanese and better than the Chinese, one supplier in China being poor for needlefelts. Furthermore neither the Chinese nor the US producers offer 1.3dtex
• Were special extruders, piping and spinpacks needed to handle the PPS melt? Yes, the chlorine residues necessitated this.
• Were there any problems with the gas in the workplace? No, it was within German limits without special ventilation.
• What were the wet-laid PPS nonwovens used for? Electrical insulation – in combination with other fibres.
• Was there still a PPS shortage. No, the market is now in balance and two or three producers have expansions underway.

Air Filtration Composite

Dr Carsten Heldmann, Global R&D Director of Fiberweb (Germany) is developing high performance air filtration media with a low pressure drop by combining fine-fibre meltblown (FFMB), spunbond and carded webs to form graduated filters. The FFMB has diameters between 0.6 and 1.4 micron and thus straddles the currently used boundary between micro and nano fibres. In one example of a 4-layer “TopFlow”composite, a top layer of coarse meltblown protected a layer of standard meltblown on top of a FFMB which had been laid on to a spunbond reinforcing layer.

Carded prefilters could be made from fibres of different denier on the same line to get an even coarser prefilter for use in HVAC. These could be laminated to the spunmelt structures using sonic bonding to minimise the loss of open area. The main message was that Fiberweb were now willing to combine their carding and spunmelt expertise to offer a wide range of air filtration products.

Needlefelts for Liquid Filtration

Heribert Kurt of Heimbach Filtration ( Germany ) said that scrim-reinforced needlefelts are generally better than woven fabrics in liquid filtration because they offer good capacity at lower pressure drop due to their bulk and permeability. In industrial process filters they can be designed to survive the often harsh chemical environments and have established themselves in vacuum belts filters, rotary drum filters and filter presses. Their main uses are in the production of:
• Minerals and zeolites, including ores, lime, diatomite, and active carbon.
• Chemicals, e.g. fertilisers
• Dyestuffs and pigments
• Pharmaceuticals and antibiotics
• Non-ferrous metals including copper, nickel and zinc and its oxides.
• Food additives

One example used a 300gsm woven monofil PET scrim with a microfiber needlefelt surface which had been densified to remove 2 micron particles of zeolite from the process liquor.

Asked how Heimbach deal with the “smile” and “frown” variations in basis weight across the width (that needlefelts are prone to and wovens not), Mr Kurt said they could compensate for these in careful calendering and heat setting to get uniform permeability. Fibre loss from needlefelts was another issue, and here again the surfaces could be stabilised in the calendar.

Liquid Filtration for a better society

Professor Richard Wakeman, a consulting engineer (UK) described the variety of filtration media now available and wondered whether they could help reduce the 2 million deaths that occur from preventable water borne diseases in regions of poor water quality. Delivering large quantities of water free from viruses and bacteria requires membrane-quality filtration, probably in the shape of membrane bioreactors (MBR). These are hybrid processes which combine active sludge anaerobic biotreatment with membrane filtration. Because the sludge fouls the membrane, bubble “aeration” is used to create turbulence and clean the membranes. Reuse of water in heavily populated regions is increasingly complicated by drug, herbicide and pesticide residues persisting through purification processes, and these require adsorbents like active carbon for their removal.

So where do the filters come in? Ahlstrom's Disruptor™ with active carbon was mentioned along with the industrialisation of nanofibre nonwovens.

Hybrid Membrane Technology

Dr Antoine Schelling of Dupont ( Switzerland ) described their new HMT filters designed to fill the gap between traditional filters and microporous films. HMT uses continuous filaments in the 0.2 to 0.6 micron range to achieve filtration efficiencies close to membranes with lower pressure drop. The filament diameters are, unlike meltblown or electrospun, controllable, and this yields controllable pore-size.

When tested according to ASTM-F795-88 with ISO ultrafine test dust in water against a cellulose/meltblown composite which targets removal of ~1 micron particles, HMT showed:
• An initial pressure drop between 0.25 and 1.2 kPa (for 5gsm and 31 gsm respectively) compared with 1.7 kPa for the composite.
• The 31 gsm HMT had an initial ability to remove 100% of 1 micron particles compared with 87% for the composite.
• The dust holding capacity of the 31 gsm HMT was 1.9 gms compared to 1.1 gms for the composite.

Applications in HVAC, bag, cabin air and cartridge filters are foreseen, as well as in battery separators. The technology is currently being used with a nylon 66 polymer on a 1.8m wide line and is commercially available in the 10 to 30+ gsm range as roll-goods.

Elmarco questions related to whether or not the process used electrospinning, what the productivity was, and what Dupont meant by high throughput did not yield any useful answers. Dr Schelling did however add that extra capacity would be added in the next year. The EDANA conference programme did describe HMT as “nanofibre from electrospinning”. The main diameter produced was 0.4 micron to match microglass.

Calvin Woodings

14 th October 2008

Man-Made Fibres Congress: Dornbirn , Austria 16-19 th Sept 2008

Introduction

730 delegates, including the great and the good of the world's man-made fibres industry, attended this 47 th annual congress held as ever in the pretty but hard-to-get-to Austrian town of Dornbirn . This year's MMFC clashed, as did the last several, with the EDANA Outlook Conference in Portugal , and so both conferences probably lost a proportion of their potential supporters. Your correspondent and others were poached from Portugal by the attractions of 120 technically-rich papers in three simultaneous sessions structured around the themes of New Fibre Developments, Safety, Sustainability, Sportswear, Nonwovens, Technical Textiles and EU Research projects.

As is often the case, the cramming of so much information into so a short time meant that papers were inevitably concise, some gems had to be missed, and the opportunities for questioning were strictly limited. This summary is biased towards the New Fibre Developments, Nonwovens and Sustainability sessions.

A Cellulosic Future?

Thomas Fahnemann, CEO of Lenzing observed that the recent period of high growth in cellulosics production was being followed by a rude awakening as demand slackened sharply in the last month due to the recessionary effects of high oil price and the credit crunch. However, the high oil price provided an excellent opportunity to promote the benefits of using natural products in a sustainable fashion. Man-made cellulosics, especially those made by Lenzing offered the low carbon footprint that consumers were increasingly demanding. They had:

• An almost energy neutral process thanks to the “solar powered” polymerisation process, the non fibrous by-products of which provided the power required by the conversion process.
• The closed-box nature of the modern viscose process which allowed minimal use of chemicals and minimal gaseous and liquid emissions.
• A CO 2 neutral production route due to the CO 2 credit from tree-farming.
• An ability to make further investments in environmental protection. These were now good PR and marketable, whereas in the past they simply spoiled the bottom-line.
  

  
  

  
  

  So, despite the immediate demand setback, cellulosics would have a great future, further expansions being driven by population growth (7 bn now to 9 bn by 2050) and increasing prosperity as the developing world raised its living standards towards Western levels.

Could the planet sustain a larger population all living at Western standards?

• The USA accounted for 25% of the CO 2 emissions, and China was now the second largest emitter (18% of total), ahead of the EU.
• Projecting current trends showed China moving ahead of the USA in 2020 as they continued to expand based on coal-fired power generation.
• Chinese coal fired power generation was growing at the rate of 1 new station every 2 days, and these plants used old technology and worked at only 23% efficiency – about half the level of current best practise. Steps must be taken to ameliorate the catastrophic effects of this.
• Western best practise must continue to improve and China must be encouraged to adopt this best practise.
• The EU was labouring under the high costs of high standards of environmental control while China was making high profits by delaying the adoption of similar standards.
• The EU should impose import duties restrict the availability of unsustainable imports.
• The development and adoption of carbon capture and storage technology was urgently needed and the EU were funding several large scale projects.
• The trade in CO 2 certificates was described as “trading in hot air”. The practise did nothing to reduce CO 2 emissions overall. It simply allowed polluters to continue to pollute thanks to the good practises being adopted elsewhere.
• A very important issue which needed addressing at a World Trade level was the disadvantage man-made fibres suffered against cotton.
• Cotton production is a dirty process requiring massive inputs of chemicals and water. The irrigation water alone would add $2-10/kilo if costed at EU domestic water prices, and yet the fibre receives government subsidies while the environmentally superior man-made products are penalised.
• The use of renewable materials such as wood should be rewarded. Of the 1.7 billion tonnes of wood harvested annually, only 10% goes through pulping operations to extract useful natural raw materials.
• Plastic recycling should be encouraged so that these oil-based polymers and fibres can be recovered at the rates now achieved by the paper and glass industries.
• Carbon footprint should be better understood and used as a primary part of any fibres specification – as important in future as tenacity has been in the past. (The group of consumers prepared to pay a premium for low carbon-footprint products is large and growing rapidly.)
• Polyester fibre has no viable alternative in world textiles. It must continue to grow but the recycling rates must be increased.
• New natural raw materials for fibres should be sought. Casein was mentioned although this would compete directly with food production.
• New sources of cellulose should be pressed into service for fibre production – straw and grasses were mentioned.

Finally Mr Fahnemann observed that whilst oil price changed hourly, fibre prices could only be changed with months of notice. Maybe the fibre industry should move towards a price indexing system which allowed similarly fast responses to change in raw material costs.

The Future of the EU Textile Industry

Bill Lakin of Euratex Brussels noted that the end of the textile and apparel quota system in 2005 was intended to usher in a period of free trade, but had failed to do this because a number of emerging countries continued to obstruct progress in the Doha round. Other problems related to the rise in value of the Euro, the fall of the dollar, increasing energy costs and the increasing burden of the REACH legislation. Doha was a double travesty: the dismantling of quotas and the opening up of markets had not been uniformly enforced and non-tariff barriers had increased. Mr Lakin hoped for its failure.

• EU Textile productivity is nevertheless growing rapidly.
• Continuous innovation is occurring and not just in technical textiles.
• The desired transition from commodity products to specialities is occurring.
• The EU is beginning to benefit from consumer concern related to air and sea freight cost/kilo of textile finishing and making up in the Far East . (Global warming/CO 2 issue)
• Ditto a reaction against ultra-low cost labour.
• “Local” trade, this including the Middle East and North Africa would be increasingly favoured.
• The biggest ever EU research programme – LEAPFROG - intended to fully automate apparel manufacture is progressing and would allow the EU to leapfrog the Far East and its use of low cost labour.

However, the average EU textile company now has only 16 employees and a turnover of about €1.4m. Consolidation was essential to survival.

Overall, the EU Textile industry is in a period of adjustment, has survived the end of quotas but continues to lose jobs. Consolidations and mergers are essential and the industry must promote the value of EU textiles to the consumer and get away from trying to match the low cost of imports. It needs to develop and maintain cutting-edge manufacturing techniques to support the anticipated growth in demand for unique items caused by the need for increasing mass customisation.

Man-Made Fibre Trade

Roger Lee of Tecnon Orbichem reviewed the man-made fibre patterns of trade of the last several years and traced the migration of business from the developed to the developing world:

• Between 1996 and 2020, world polyester staple production will have grown from 6 million tonnes to 30 million tonnes, Chinese expansion accounts for all of this growth. (Expansion in other Eastern countries simply making up for the decline in the West)
• The numbers for polyester filament yarn production are similar (7 million to 42 million tonnes all in China )
• China apart, nylon filament production has been more or less static since 1985 when China was a minor producer. By 2020, China will have 35% of the World production total of 4.3 million tonnes.
• Acrylic fibres are due to decline from the peak of 2.7 million tonnes in 2005 to 2.3 million tonnes by 2020, despite the Chinese share expanding from 30 to 40%.
• In 2007 the EU imported 1.3 million tonnes of trousers and T shirts.
• Of the 0.25 million tonnes of nonwovens imported in 2007 38% were from North America, but Chinese imports are increasing, as are those from Israel , Turkey , the Middle East and North Africa .
• Cellulosics were not mentioned.

For the future, Mr Lee concluded that while the West will continue to produce man-made fibres, these will support a few key local industries producing products with unique qualities for local markets.

Fibre Innovation in Japan

Akihiro Omatsuzawa of the Japan Chemical Fibres Association provided an overview of recent developments in Japanese fibres.

• Production had declined by half a million tonnes in the 10 years to 2007, when 200,000 tonnes of cellulosics and 1.1 million tonnes of synthetics were produced annually.
• Since 2000, cellulosics production had grown by 6.5% p.a. while all other man-made fibres had declined.
• Usage in the apparel sector had declined most (392 to 244), but home furnishings had also suffered (460 to 404). Industrial textile usage had however grown from 288 to 326 ktonnes/year.
• Nanofibre developments were now taking center stage:
  • Toray were developing a 44 dtex textile yarn with 1.4million filaments
  • Teijin's Nanofront™ was a high strength 39dtex polyester yarn with 8360 filaments
  • Morphotex™ from Teijin was a nanostructured optical interference fibre.
  • Black Sophista™ from Kuraray was an EVAL/Polyester nanostructured fibre.
  • Mitsubishi Rayon's AHF was an acetate-containing acrylic nanocomposite fibre.
• Toray's nanoMATRIX technology was targeting the development of nano-scale coatings.
• Kuraray's Kuralon EC was a conductive PVA fiber using metal nano-particles.

Examples of functional textiles based on these or related technologies were:

• Ventcool™ - a Mitsubishi Rayon fabric based on triacetate conjugate fibre which is “cubically transformed” by moisture. The result is a fabric which opens up to give improved breathability as it gets moistened by perspiration.
• Sophista™ - a polyester from Kuraray with ethylene vinyl alcohol content to allow rapid moisture absorbtion and release.
• Lonwave™ - a polyester from Kuraray with ceramic powder content which radiates far-infrared.
• Moiscare™ by Toyobo is an acrylate fibre which heats up as it absorbs moisture.
• Hollow thermal polyester fibres, Aerotop™ from Teijin and Airmint™ from Kuraray, the latter looking like an islands in a sea bico where the islands are air.

Others were relatively well-known high tenacity products such as the para-aramids (Twaron™, Kevlar™ etc), the high MW polyethylenes (Dyneema™), the ultra high strength PVA (Kuralonk-II™), PBO fibres (Zylon™) and the Polyarylates (Vectran™). For high heat resistance the meta-aramids were exemplified by Conex™ and Nomex™, PPS fibres by Torcon™ and Procon™, and Polyimides by Toyobo's P-84™.

Recent and current government-sponsored R&D consortia targets include:

• Doubling the strength of general use polyester and nylon without doubling the cost. (1 billion yen)
• Ultra light “smart” fibres using “nano-level compounded process technology” (0.64 billion yen)
• Use of super-critical CO 2 to dye polypropylene and aramids with aqueous dyes, and to apply chitosan functionality to polyesters. (0.63 billion yen)
• Thermoplastic cellulose for melt spinning (0.36 billion yen)
• Synthesising aliphatic polyketones for high performance fibres from CO and ethylene. (0.5 billion yen)
• Recycling polyester/cotton textiles using melt separation of the cotton for use in composites. (0.6 billion yen)

For the period to 2020, the METI Strategic Technology Roadmap for the Fibre Industry places priority on R&D for Material Security (replacing fossil materials with biomass); Carbon Fibre composites; Construction, IT and Living; and Base Technology, i.e. the technologies required to allow the other 3 priorities to create new markets and meet social needs e.g. “safe and enriching life” and “friendliness to nature and the environment”.

Biopolymers for Textiles

Roy Dolmans of RWTH Aachen described the EU funded Biotext consortium, set up to evaluate the synthesis of blends and copolymers of commercially available biopolymers such as PLA, PHB and some starch-based polymers. He defined biopolymers as biodegradable polymers so as to include biodegradable synthetics, and mentioned that any polymer now commercial would be excluded from the project.

The paper included data on a PHB/PLA blend which had been synthesised, analysed and spun into monofilaments. The PHB was from the bacterial process and cost 10 times the PLA polymer. It was prone to degradation during extrusion and so the work was restricted to blends with less than 20% PHB. Possible applications in medical products or geotextiles were envisaged.

Spunlaid Lyocell Update

Malcolm Hayhurst of Lenzing explained the logic behind the recently announced collaboration with Weyerhaeuser aimed at building a pilot line for the spunlaid lyocell technology.

• Weyerhaeuser had, and could continue the optimisation of, the Peach™ kraft pulp which worked well in the lyocell process and cost less than dissolving pulp.
• Their earlier independent work on lyocell spunlaid, followed by the collaboration with Reicofil at Fraunhofer Institute meant they had developed useful expertise and intellectual property.
• Their pulp and paper technology could contribute to the wet-laying and drying parts of the operation.
• Reicofil, who had earlier announced a collaboration with Biax Fiberfilm to develop the special spinerettes required by lyocell spunlaid were now working independently and were not contributing to the Lenzing/WH project.
• Lenzing had their own spinnerette manufacturing technology and would develop the jets themselves.

Work continues on the process with emphasis on improving productivity:

• Peach™ pulps with alternative molecular weight distribution are being evaluated.
• The effects of higher extrusion rates and stretching are being evaluated
• Basis weights from 10 to 200 gsm have been made with dry strengths in the range of 200 to 3500 N/m (EDANA 20.2-89), and wet strengths in the range of 60 -500 N/m
• Fabric Water Imbibitions (DIN 53814) vary from 70 to 160%, and Total FreeAbsorbency (EDANA 10.4-02) from 300 to 800%
• Tests against a clean-room wipe specification indicated low lint levels (for the spun-laced continuous microfibers)

For the future, the mothballed “SL1” lyocell plant in Mobile Alabama could provide a low-cost route into a fully commercial scale.

Environmental Assessment of Cellulosics

Martin Patel of Lenzing re-presented the data provided at earlier conferences which compared the impacts of Lenzing's cellulosics with cotton, polyester and PP. This version showed that their new Chinese viscose operation had a higher environmental impact than their other operations in Europe and the USA due to the non-integration of the pulping operation (compared with viscose in EU) and the Chinese use of low-efficiency coal-fired power stations for energy generation.

Current EU viscose was better than current lyocell due to the integrated process, but the “Tencel 2012” process which would use municipal solid waste incineration to provide power would have the lowest impact of all – up to the factory gate. The consumer use phase had not been considered and here the more difficult drying of the absorbent fibres could be expected to change the comparisons with polyester.

In a separate paper by Jim Taylor of Lenzing , the ecological benefits of dyeing and finishing Tencel textiles were enumerated. Tencel dyes darker than cotton and so needs 1/3 rd of the dye to achieve the same shade. It also needs only 40% of the salt, loses less dye in the wash-off stage and gives a dyehouse effluent with half the chemical oxygen demand of a cotton dyehouse.

PCM in Lyocell Fibres

Marcus Krieg of TITK introduced the Smartcell™ clima fibre, an alloy of cellulose and a phase change material made using lyocell technology. Unlike the related viscose-based product produced by Kelheim Fibres using the Outlast™ encapsulated phase change material, the TITK process uses the PCM directly and disperses it in the dope with the aid of an inorganic nanoparticle .

6.7 dtex staple has been produced with good strengths despite high loadings of PCM, the final fibre being 51% cellulose, 36% paraffin wax and 13% inorganic filler. The heat storage capacity is 60 J/gm fibre, and the fibre has a smooth surface, is easy to process, comfortable to wear, and suffers no loss of functionality on washing. 1.7 dtex is being developed this year and this requires re-optimisation of the nanocomposite to prevent higher losses of the paraffin in use. Overall mechanical properties are similar to viscose fibre, i.e. half those of unmodified lyocell fibre.

Lyocell Carpets?

J Männer of Lenzing provided an introduction to carpet technology and markets and made a case for the new 15dtex/150mm Tencel fibre in carpets either alone or blended with wool and synthetics to make comfortable carpets.

• The high moisture regain of Tencel would improve room climate and hygiene and kill the static propensity of the synthetic. (2 people give off 1.75l of water during the night and a Tencel carpet could absorb 3 litres – and prevent condensation on the windows of a 50 m 3 room.)
• It inhibits the growth of Staph aureus (by having no free water on the surface), is anti-allergenic and mothproof.
• It is biodegradable and eco-friendly.

The low abrasion resistance, poor recovery from compression, lack of bulk and very high pile cost compared with BCF nylon were not mentioned.

PLA Update

Eammon Tighe of Natureworks – now a JV between Teijin and Cargill – described how they were continuing to improve their eco-profile by looking for reductions in process greenhouse gas emissions. The lactic acid production from dextrose was the main source of GHG's and had become the target of further development. “PLA5”, the benchmark 2005 process, had been improved by buying renewable energy certificates based on wind-power to give the “PLA6” process which would be in operation until 2009. Then the next generation process “PLA-NG” using “new technology and green power” would kick in. After that, “Long Term” would use new sources of biomass for lactic acid production and green power generation.

• PLA5 to PLA6 reduced the non-renewable process energy use from 50 to 27 MJ/kg.
• PLA6 to PLA-NG would reduce it further to 17 MJ/kg.
• GHG emissions (kg CO 2 /kg polymer) would fall from 2 kg with PLA5 to 0.27 kg for PLA6
• PLA-NG without wind power would yield 0.75kg, and be a CO 2 absorber with wind-power. (removing 0.67 kg of CO 2 )
• Water usage by the process was comparable to other synthetics and much less than cotton
• With regard to the food v bioplastics debate, Ingeo™ PLA polymer uses less than 0.04% of global corn supplies, and bioplastics are tiny users compared with biofuels.
• Cellulose to PLA processes are being developed.

Current Natureworks output is about 80,000 tonnes/year and 70% of this goes into packaging, the rest fibres. Products made from fibre now include the usual examples of designer apparel, spunbond carrier bags, short-life needled carpets, geotextiles and agritextiles. Interestingly, Mr Tighe said they no longer promoted composting as a disposal route. Recycling is the main option.

A plant expansion will come on stream in 2009.

Dental Care Fibres

Michael Müller of Pedex , since May 2007 a subsidiary of Lenzing Plastics, provided an overview of the wide range of fibres developed to make better toothbrushes:

• Polymers used include PA 612, PA610, PBT, TPE, PMMA and POM.
• Most cross-sectional shapes and types of bicomponency are made
• Fibre diameters are in the range 0.1 to 0.3mm, with sheaths in the 6 to 30 micron range.
• Spiral Magic Filaments have a square section with a pigment in one corner. When twisted these give a unique glistening appearance and high cleaning efficiency. (Bristle cleaning action is quantified by the University of Ulm .)
• Whitening filaments are sheath-core with a fluoride donator in the skin layer which also gives the filament a rougher surface and hence better cleaning efficiency than either round or trilobal filaments.
• Wear indicator filaments have a thin coloured sheath on a white core. The sheath is designed to wear away over 3 months and indicate the need for a brush change.
• Sensitive structure filaments have a soft gum-feel arising from a foamed sheath polymer on a nylon core.
• Structure filaments have large lumps of coloured polymer embedded in the surface to provide enhanced cleaning
• Defined Flagged/Finger filaments are round fibres with a quadrant bicomponency which splits into 4 finer filament as the brush is made. The fine filament ends can be rounded after splitting. Cross section photos suggested the quadrant was in fact the core of a bico fibre with a thin sheath.
• Rubber-soft filaments are sheath-core bicomponents of PBT and TPE-E, the latter having a high rubbery friction which gives efficient cleaning due to the high wet friction.
• Rubber-structure filaments appear to be a variety of rubber-soft where the core has shrunk longitudinally and the skin has corrugated under compression. They have a very high surface area which enhances the friction effect.
• Antibacterial filaments based on Silver Zeolite in the skin are to protect the brush against bacterial growth when stored wet. PBT filaments are also made with 2.5% of Irgaguard B5120. Nanosilver filaments use silver particles in the skin

Fibres are supplied to J&J, P&G and GSK among others.

The Future of Spunmelt Technology

Hans Georg Geus of Reicofil reviewed the evolution of the nonwoven market and the basics of spunmelt technology before revealing some information about their sales:

• They have delivered 180 Reicofil lines.
• 17 of these were R1, 39 were R2, 71 were R3 and 36 were R4 systems,
• Of the R4 lines, 3 had just one spunbond head (S). 9 were SS, 7 were SSS, 7 were SMMS, 5 were SSMMMS and 4 were SMMMS
• Another 17 lines used just one M (meltblow) head.

Improved meltblowing heads with 35 holes/inch now allowed the production of hygiene fabrics with higher and more uniform hydrohead across the width of the fabric. (820mm -4% and +2% mm H 2 0 now compared with 700mm -9.5% and +6% earlier). Air permeability consistency across the width was similarly improved. Fibre size distributions were also better, 70% of the meltblown filaments being in the 0.1 to 1.0 micron diameter range. These improvements were leading to better filtration performance, or, a halving of basis weight required for a given particle retention level. 50 holes/inch stabilised meltblow heads were now under development.

What did the future hold? In hygiene Mr Geus saw great growth prospects in the emerging economies and increasing usage of renewable raw materials such as PLA and cellulose. There would also be a need to combine different technologies, presumably including HE bonding for the cellulose fibres. In technical products he saw spunbonding being the first nonwoven systems into the emerging economies, leapfrogging rather than replacing card/bond systems. Here again, bonding systems other than thermal would be needed.

Hollow Filament Spunbonds

W. Schilde of STFI described their project to produce nonwovens from hollow filaments of PP, MPP and PET prior to bonding them thermally, hydrodynamically and mechanically.

Spinnerettes with 24 and 90 “double C” and “triple C” slots were used to form the hollow structure in preliminary trials on a fibre line. Hole external diameters of 1mm and 1.2mm were used, the C-slot widths being 0.15, 0.18 and 0.21mm.

For the Reicofil 4 line, a 7360 hole jet with “double C” holes was chosen, these having an external diameter of 1mm and a C-slot width of 0.15mm.

• Best hollow structure was obtained with 15-25 MFR polymers, used at high throughput and low cooling temperature on the R4 line.
• Jet configuration, air speed and stretch ratio had minor effects on cross section, but the high air speeds spoilt spinning reliability.
• Hollow core size could not be increased above about 15% of the total cross section area, PP allowing bigger holes than PET.
• The circular cores were deformed to ovals by all the bonding methods.
• The hollow fibre structures had the same strengths as the solid fibre structures.

Assessing Sustainability

Bob Barker of the American Fiber Manufacturers Association observed that most environmental standards don't measure sustainability. He listed the main environmental concer as:

• Greenhouse gas emissions (i.e. water vapour, CO 2 , Methane, Nitrous oxide, Ozone and halocarbons)
• Air, water and land pollution
• Solid waste disposal
• Water use, water quality, eutrophication and acidification.

These were now being addressed by new standards for the carpet and home furnishings industries.

Finished product use and maintenance proved more important than textile production in an assortment LCA data presented:

• Cotton fabrics required 85 kwh/kg for washing and drying during their lifetime, whereas 100% polyester needed 20 kwh/kg – unless of course they were hand washed and line dried.
• 82% of the energy required in the life cycle of a polyester blouse was consumed during use.
• 80% of the blouse GHG emissions occurred during its useful life.
• Wool requires seven times the land use, has 3 times the global warming potential, 50 times the photo-oxidant creation potential of cotton, and has 5 times the eutrophication potential the latter being due to ammonia production during the sheep's lifetime. Polyester was best of all on these counts.
• Textile tablecloths were better for the environment than disposables on all counts but water usage.
• End-of-life aspects can dramatically affect conclusions. Extending a products life will enhance its sustainability rating, while recycling can offset the impacts of the fibre production process.
• The carpet recycling plant in Dalton Georgia works with post consumer waste carpets returned in the trucks used to deliver new carpets. The nylon pile is shaved off and recycled by depol-repol via caprolactam.

Sustainability and Nonwovens

Pierre Conrath the Sustainability and Public Affairs Manager of EDANA listed the contributions nonwovens make to improving our environment:

• Oil sorbents for controlling and cleaning up oil spills.
• Protective clothing for environmental control personnel
• Filters for cleaner air and water
• Crop protection covers
• Battery Separators (Renewable Energy Storage!)
• Publication of Environmental Guidelines in the 1990's
• Life-cycle assessments on diapers and inco products.
• EDANA Sustainability Reports
• Environmentally-oriented conferences and committees.

EDANA is now planning a review of sustainability strategy using an external panel of experts and would focus on the design and implementation of good sustainability practices throughout the supply chain. This would involve developing methods to quantify sustainability and its counterpart “Convenience”. Life cycle assessment was key to the former, and would be extended to “cradle to cradle” studies. A new “Right for Hygiene” programme would set the record straight and highlight the benefits arising from hygienic disposables and personal care wipes.

The EU “Sustainable Consumption and Production Plan” proposals would encourage green public procurement, eco-labelling, eco-design, eco-management and eco-auditing schemes. Mr Conrath thought this type of EU legislation would have a global impact as other countries adopted EU policies. The green public procurement initiative would target 50% of all public authority purchases being green by 2010.

Sustainable Polyester Development

Emanuele Pivotto of Sinterama Spa introduced the company and its activities and said they were pledged to minimise their environmental impact, use cleaner production methods and develop earth friendly products, one of which was CoCoNa yarn. This appeared to be a polyester yarn loaded with active carbon from coconut shells. The yarn allowed fabrics made from it to dry in half the time and absorbed body odour so that a garment could be worn for longer without causing offence. RecyPES was a recycled polyester made by depolymerisation and repolymerisation of bottle polymer.

Ecological Aspects of Man-Made Fibres

Robert Kirkwood of Invista listed the objectives of their Apparel Planet Agenda. They wanted to minimise the carbon footprint of synthetics, improve the carbon footprint of natural fibres by improving their performance, and increase the longevity of clothing.

Life Cycle Analysis as covered by the ISO 14040 series of standards was the tool being used to meet their objectives. As used by Marks and Spencer, LCA has shown that for apparel textiles, the consumer-use part of a garment's life dominates its environmental impact, accounting for over 75% of the total life cycle. Polyester trousers for example last 2 years, are washed 92 times and dried in a tumble dryer on average 46 times during their life.

The biggest reductions in impact along the textile supply and use chain are therefore achieveable by:

• Cool water washing
• Line drying rather than tumble drying
• Not ironing
• Wearing for longer periods between washing
• Keeping clothes for longer and avoiding fashion items.

Eco-processing of Polyester

Paul Roshan of LEITAT, a technological research centre for textiles in Spain discussed ways of making polyester more hydrophilic or hydrophobic.

The traditional route involves treatment with 2 molar caustic for up to 8 hours at 50 o C, rinsing and neutralising with acetic acid. An alternative bio route involves treating with enzymes at 30 o C for up to eight hours followed by 15 minutes at 60 o C to kill the enzyme before rinsing off. Esterase, the best of the enzymes tested, rendered polyester hydrophilic in less than 1 hour, while lipase (2 nd best) required 4 hours to reach the 2 seconds level in the water drop absorbtion test.

Plasma-enhanced chemical vapour deposition achieved hydrophilicity when acrylic acid or acrylamide precursors were used. The same technique could render a polyester/lyocell woven fabric hydrophobic to a 120 o contact angle in 10 minutes when perfluorohexane was used as the precursor. However in any subsequent wet processing (washing) the lyocell tended to fibrillate and this destroyed the hydrophobicity as new untreated cellulose surface was exposed.

“Made in Green” Polyester

Xavier Valera of Fibras Europeas de Poliester ( Spain ) wondered how a small polyester producer was going to survive when by 2010 87% of the world's synthetic fibres would be produced in China . His answer was to Go Green and get the ecological and social product certificates to prove it. The “Made in Green” scheme by the Aitex Institute of Technology was chosen to help compete against low-quality products that might contain hidden harmful materials, made in countries which do not respect international guidelines regarding contaminants or worker protection.

The certification guarantees:

• Freedom from harmful substances to Oeko-Tex 100 standard
• Respect for the environment to ISO 14001 or Oeko Tex 1000.
• Respect for human rights to International Labour Organisation and United Nations standards as listed in the Code of Conduct and Social Responsibility drawn up by Aitex.

Traceability through the entire production chain is the key.

New Polyester Fibres

T Kobayashi of Teijin Fibres mentioned how the denier of their Tepyrus short-cut polyester for wet-laid nonwovens was being reduced below the normal 0.6 dtex into the nano range. A new 0.07dtex short-cut is allowing the wet-lay process access to the durable synthetic leather market when combined with hydroentanglement bonding. It is also allowing the production of ultra-thin paper for battery separators and stencils for screen printing. Aspect ratio is the key to good formation and values of around 1000/1 L/D are needed. This means the fine fibres need to be cut to 0.6 to 0.8mm length to allow dispersibility

Teijin's ELK™ is high-loft cushion made from a blend of a binder fibre and a matrix fibre. The binder fibre has a polyester elastomer sheath covering an off-centre polyester core. The matrix fibre is a PTT/PET bicomponent with a low modulus and a spiral crimp. The blend is through-air bonded to let the elastic binder polymer concentrate at fibre crossing points. This renders it capable of giving softer cushions than standard polyester fillings. Unlike the PU foam with which it competes, ELK™ is fully recyclable into plastics or combustible without generation of any toxic gases. It also demonstrates better compression durability and breathability than the equivalent PU foam. It has now been adopted for Japan 's bullet-train seating.

Health and Safety of Nanofibres

L.L.Bergson of Bergson and Campbell (USA) said nanotechnology was defined by the EU as the “study of phenomena and fine-tuning of materials at atomic, molecular and macromolecular scales where properties differ significantly from those at larger scale”. In the USA , Nanoscience was defined as “research to discover new behaviours and properties of materials at the nanoscale (1-100nm)” and Nanotechnology as “the way discoveries made at the nanoscale are put to work”.

Current EU regulations cover in principle the potential health, safety and environmental risks of nanomaterials, but they are not explicitly mentioned under REACH regulations. Non governmental organisations are calling for revision of the 1 tpy registration threshold where nanomaterials are concerned and there is at least the potential for nanomaterials to become subject to separate authorisation.

In the USA , the Federal Government argues that existing statutory authorities are adequate to address the oversight of nanotechnology and its applications, but will “adapt or develop additional approaches as necessary”. The US EPA argues that particle size does not affect molecular identity and if the chemical is already listed on the Toxic Substances Control Act Inventory a nano version would not be subject to separate premanufacture notification. However, the EPA regards carbon nanotubes and fullerenes as new chemicals even though they are just forms of carbon.

Meltblown Melamine Nonwovens

Ulf Panzer of Agrolinz Melamine International has been collaborating with TITK Rudolstadt to produce thermoset microfiber nonwovens from a new extrudable HIPE®ESIN MER melamine. AMI is a 100% subsidiary of Borealis AG with 160,000 tonnes/year melamine capacity split between Linz in Austria and Piesteritz in Germany . Melamine thermoset resin is made (like fertilizer) from air and natural gas via ammonia and urea. Its main uses are in mouldings, textile and paper finishes, flame retardant additives and adhesives. The new Hiperesin has a thermoplastic “window” between 90 o C and 140 o C which allows extrusion into fibres and meltblown nonwovens which can then be thermally cross-linked into thermoset products with inherent flame resistance and a decomposition temperature of 400 o C. The cross-linking process requires temperatures above 200 o C for 2-3 minutes, the limitations on oven length limiting the speed of any nonwoven operation. Some slides suggested a catalyst was used in cross-linking, this catalyst being removed in the oven to leave a volatiles-free nonwoven.

The meltblown webs shown were remarkably soft and clearly contained very fine fibres. Applications envisaged were flame-barrier mattress pads, hot gas filtration and heat/sound insulation for engine compartments.

Asked if formaldehyde was released as the decomposition temperature was reached, Mr Panzer did not know. He said the product was similar to Basofil™ flame retardant fibres.

Applications for Meltblown Melamine

Ina Sigmund of STFI has been developing applications for the meltblown melamine nonwovens mentioned above. She found the webs easy to needlepunch provided fine needles were used at low speeds, and easy to hydroentangle. Layered products using the bonded melamine nonwovens for use in protective clothing, filtration, bedding and upholstery were demonstrated. In filtration, performance of the self-bonded microporous meltblown structure when applied to the surface of a needlefelt gave a high contaminant holding capacity, high filtration efficiency and lower pressure drop than the equivalent membranes.

Recycling from Post Consumer Waste

Andreas Bartl of the Vienna University of Technology considered 3 cases of fibre recovery from waste: deriving fibres from tyres, from waste apparel and from the municipal shredder “light fraction”.

Tyre-derived fibre is 50% viscose, 20% polyamide and 30% polyester. It is obtained after grinding and appears to be like fluff pulp with some rubber powder contamination. It can be used to reinforce bitumen for road surfacing where it helps to prevent surface cracking, or as a viscosity modifier in lacquers.

End of life apparel recycling is a publically-funded consortia project with the aims of avoiding landfill and incineration of textiles by use of a low energy automated process to recover fibres for reuse. The apparel which has usually been rejected by charity shops as unsuitable for further wear is ground up, and has any non-fibrous content separated by various means (“magnets, sifters, etc”). The fibrous output is separated into long and short, the latter being used for reinforcement of bitumen, concrete, plaster board and pastes while the former is reused in textiles and nonwovens.

Shredder light fraction contains about 20% of fibres which can be extracted and used like the tyre derived fibres.

It was unclear which of the above were aspirations and which were commercial achievements.

Sanitized Silver

Dominik Zimmermann of Sanitized AG promoted the use of their T25-25 Silver product which unlike the usual TiO 2 /Ag products is effective against athletes foot. It can be applied to textiles along with other fabric finishes and achieves a much higher exhaust rate than competitors (>90%). Treated fabrics are washable and dry-cleanable and are being used to make skin contact sportswear, footwear and functional underwear. In addition to controlling perspiration odour, they are being marketed on a “stay cleaner for longer” basis because they need less washing, and when washed at 30 o C the silver gives improved cleanliness.

Odour control in Sportswear

Dirk Höfer of the Hohenstein Institute has evaluated a variety of antibacterial agents used in sportswear. He listed silver, triclosan, quats, chitosan, polyhexanide and copper compounds. To the usual range of tests for an antimicrobial he added the need to quantify odour control, both subjectively and objectively. He provided snippets of information but only on the silver products:

• Silver-containing fibres give a log 2-3 reduction in organisms
• Silver-coated fibres give log 4-5 reductions
• Silver-finished fibres give log 3.5 to 4 reductions
• Duration of sporting activity is a key issue: squash is over in 1 hour but cycling can go on for 6 hours or more.
• Silver-containing fibres are slow-acting and take 4 hours to be effective – so these might be appropriate for cycling
• Silver-coated fibres are effective in less than 1 hour and would be appropriate for squash.
• Silver-coated fibres worked well for odour absorbtion.
• Skin-Silver interactions had been studied to show silver was non-toxic, non-allergenic and non-mutagenic.
• It had no effect on skin flora.
• Sweat from skin under silver-coated garments contained only 5300ppb Ag, while the skin surface contained 93ppb and the subcutaneous region 1 ppb.
• The main message seemed to be if you want to make claims about the effectiveness of antimicrobial textiles, Hohenstein has the technology to validate those claims.

Mr Sun of the China National Textile and Apparel Council said a few words. 45% of the 78.4 million tonnes of fibre produced in 2007 were from China , and China imported 2.2 million tonnes of cotton. Sustainability initiatives were evident, bamboo being used as a raw material for viscose production, and 4 million tonnes of polyester was being recycled. China was also developing more sustainable varieties of cotton by genetic modification.

Nataliya Federova of NC State won the Albrecht Prize for Innovation for her paper on nanofibres from bico nonwovens. She was unable to attend the conference and a colleague presented a summary of her work. Nanofibres were defined as sub-half micron diameter fibres and these could be made from islands-in-a-sea spinning of 360 nylon islands in a PLA sea. The strong filaments were easily hydroentangled and the PLA could be dissolved by hot alkali. Interestingly, if the sea was used to thermally bond the structure, some nanofibres were exposed and the resulting fabric had 3-4 times the strength achieved by hydroentanglement alone.

Calvin Woodings

Going green in the Textile World

Marcia Zaroff, founder of Under the Canopy USA is dedicated to providing the consumer with a fusion of fashion, wellness and social responsibility, and hence specialises in providing a range of “cool organic fashion” without compromising quality or performance. She stressed the significant link between organic food and organic garments: not only did they appeal to the same consumers, but 60% of the weight of the cotton harvest goes into food as oil. Her preferred fibres were organic and Fair Trade versions of wool, cotton, silk, angora and linen, but she did also use Tencel, bamboo, and seaweed. Dyes had to be low impact, indigo was recycled. All suppliers had to demonstrate social responsibility, fair labour policies and animal rights as core values. Miscellaneous points made:

• The US consumer feels he has more impact on the planet’s health by buying the right things than he does by voting.
• The organic fibre market was growing rapidly – at 44% pa between 2005 and 2010 according to the first line on a slide and at “an average annual growth rate of 116%” on the next.
• Organic cotton was a $245million business in 2002 and will be a $6.8 billion business by 2010 - presumably at retail level.
• Organic cotton sales more than trebled from 20 million in 2005 to nearly 70 million in 2007 - no units provided.
• Organic cotton needs to be certified: some unscrupulous suppliers claim organic if they avoid pesticide spray for the year’s production.
• Nike target 5% organic cotton use by 2010
• every time we increase costs by doing the right thing we make more profit” (Patagonia Clothing).

Her company partnered with the Environmental Media Association, NRDC, the Rainforest Foundation, the Rainforest Alliance, the Soil Association, the Rodale Research Institute, Amnesty International, Stop Global Warming, the Waterkeepers Alliance and the CA Coalition for Clean Air.

Asked why she used bamboo fibre, Ms Zaroff said this fast growing weed brings an interesting new handle. Did she know it was viscose rayon made from bamboo pulp in one of the more polluting and environmentally unfriendly Chinese factories? No – she thought it came direct from plant. Another audience member commented that the Chinese are working on a new mechanical extraction process to make a bamboo bast fibre, but any fine fibre with a soft handle is made using the rayon route.

Asked about US Organic cotton she said US farmers find it hard to go organic: they lease the land and can’t invest in building soil quality. They also harvest mechanically – a process with a large carbon footprint. So if you want to buy certified organic cotton, invest in, and buy direct from farms - offshore.

Challenging Sustainability

Dr Alfred Strigl of the Austrian Institute for Sustainable Development recycled his Outlook 2006 paper and listed the challenges of the age of rising temperatures and sea-levels:
· 1 to 3oC average temperature rise by 2050.
· Sea-level to go up by 0.1 to 0.3 metres by 2050.
· More natural catastrophes due to more energetic climate.
· Water shortages due to run-off pattern changes.
· World population to rise from 6.4 billion now to 10 billion in 2050.
· Along with rising population come issues related to food and water, hygiene, energy, information, human rights, terrorism, mass migrations and disease.
New points in this talk:
· US credit market debt has been rising since 1950 and moved above 3 times USA GDP in 2005 ($33.6 trillion debt)
· US “Genuine Progess Indicator” (whatever that is) has been declining since 1970
· The 3rd world pays $135million/day interest on its loans compared with receipts of $57 million/day in aid.


The annual increase in population is equivalent to a new country the size of Germany while annual soil degradation means an area the size of Germany becomes unproductive desert. Food production is declining and the rate of loss of species, especially marine species means the natural food chain diminishes. Using a financial analogy, we’ve managed to live off the Earth’s interest until 1975, but since then have been consuming both interest and capital, and the capital reserves are now dangerously low. The Club of Rome “World 3” model predicts that by 2040, on a “Business as Usual” basis:
• Natural resource availability becomes critical.
• The persistent pollution index reaches 10 times the 2000 level
• Food availability peaks and starts to collapse
• Industrial output peaks and starts to collapse
• World population peaks at about 10 billion and collapses to 3 billion by 2100


Our only hope is that humanity is intelligent enough to deal with the problems it has caused by replacing growth targets with sustainability targets. Assuming an immediate “Earth turns around to Sustainability” basis, the same Club of Rome model predicts:
• Natural resource availability does not become critical until 2100.
• Industrial output levels off and stabilises at 2015 levels.
• Food availability declines slightly to 2040 and then increases as…
• Persistent Pollution Index peaks at 4 times the 2000 level and begins to decline from 2040.
• World population stabilises at around 7.5 billion.


The ability to feed the growing population is becoming critical. Actual world grain production per capita had been declining since its 1983 peak of 342 kgs/person and stood at 290 kgs/person in 2003. Assuming it is all used for food, and not as as source of bio-ethanol, this is enough to feed 2.5 billion people at US levels of consumption or 12 billion people at the average Indian level of consumption. Ocean Biomass (seafood availability) is now at 40% of the level of 1950 and on a business as usual basis will be zero in 30 years. Meat production now accounts for 20% of all greenhouse gas emissions, is totally unsustainable, and must decline.


On the bright side, a Sustainability Megatrend is beginning to appear in Germany:
· The land area used for growing renewable resources has increase eightfold since 1993 (to 1.6 million hectares)
· The number of “bio” or “organic” labelled products has increased from 1000 to 35,000 between 2001 and 2006
· Spending on organic foods has trebelled since 1997
· Ethical investments in Germany, Austria, Switzerland and Luxembourg are rising exponentially and are up tenfold on 1997.
· Sustainability issues are now reported in 2235 German company annual reports compared with 360 in 1997.
· The market for Fair Trade products in Austria is up 5-fold since 2002.
For Dr Strigl, a Lifestyle of Health and Sustainability (LOHAS) should be adopted by all if we are to avert disaster.