Fewer than 600 delegates attended this 48th annual congress, the numbers being down by over 100 on last year apparently due to companies reducing their travel budgets. Of the ~100 presentations, about 60 were provided by European universities and technical institutes, the majority of the industrial presentations being offered in the last few months. This year's main themes were New Fibre Developments, Fibres for Medical and Hygiene, Fibres for Composites, Fibres and Textiles for Climate Change and EU Research Projects. As always the three simultaneous sessions were tightly scheduled with limited time for questions. This report concentrates on the New Fibre Development conference which ran throughout.
KeynoteFriedrich Weninger, President of the Austrian Man-Made Fibres Institute and CEO of Lenzing Fibres opened the conference. He reflected on the collapse of Lehman Brothers exactly a year ago and wondered if unabated capitalism had now run its course. Responsible management would be the key to the future. Companies would have to be fair, reliable and trustworthy and take long-term value-oriented decisions. They would consider the interests of all their stakeholders and involve them in key decisions made transparently and in a spirit of true partnership. They would also have to be increasingly farsighted, using economic principles to solve the growing ecological problems.
Sustainable development would have to be promoted globally as well as locally. Nature would be the model as it is within Lenzing. Growth would continue to be a target, but this growth would have to be qualitative rather than the quantitative growth of the past. “Renewables-Good, Fossil-materials-Bad” would continue to be the driving force, but of course wood should not simply be burnt to produce energy. It is a high-value resource, and should be used to make high-value products, energy-extraction being an end-of-life-cycle option. A focus on carbon footprint is not enough. We need to treat soil and water degradation as equally important. In summary, “we need to become as intelligent as ants”. (a reference to the “waste as food, cradle-to-cradle” thinking of Professor Braungart).
New developments in China
Mr Cheng, the Chairman of China’s Chemical Fibre Industry Association had arrived unexpectedly with a large delegation and this short paper was a last minute addition to the opening session. Speaking through his own interpreter and without visual aids:
- GDP Growth in 2009 would be 7.1%. Q2 had shown an increase of 1.8% over Q1.
- Internal demand was accelerating, restructuring of business was proceeding, and people were getting increasingly wealthy.
- There were instabilities related to regional variations and inherent problems between industries which left many challenges and risks to be addressed.
- There was still some overcapacity and some instability of supply, but the government had strong policies to improve the economy.
- The chemical industry has withstood the recession well. September to November 2008 were difficult months but growth had returned.
- From March to July 2009, prices had increased by 15%, cash-flow was good and investments were growing.
- The chemical fibre industry sector was in fact leading the industrial
- It was more confident and more disciplined
- TPA price had stabilised (no change since November last) and decoupled from the price of crude oil.
- 76% of the capacity for chemical fibres used advanced technology and this is being upgraded and revitalised to allow the phasing out of the older technology over a 3 year period.
- This will allow the proportion of differentiated or speciality fibres to increase from 39 to 50% of the total.
CCFIA is looking for partners to further develop differentiated fibres. In particular the fibre industry is hoping to collaborate with Western companies in Pulp, TPA and MEG expansions.
Climate Change – A biologists view
Joseph Reichoff of the Zoologische Staatssammlung Munich provided an alternative opinion on climate change, reminding us that because most biological processes are temperature dependent, often sensitive to 0.1oC, a history of biology is a history of temperature change. The earth has never had a stable climate: it always varied, the changes now being affected by human population and economic growth. With population growth come increased land under agriculture and an increasing livestock population. Compared with humanity, there is 10 times the live weight of food animals, and these make methane, a much worse GHG than carbon dioxide. Humanity also requires increasing energy generation to sustain the increasing population in the lifestyle to which it has become accustomed.
- Our metabolism works best at 27oC, but we can adapt to almost any climate on earth.
- There is no “right” climate, but the 19th century, to which many would like to return, was not the best.
- The earth is now a degree warmer on average than it was in 1880 but global averages are biologically meaningless: it’s the range and the extremes of temperature within particular regions that matter.
- Since the last ice-age (i.e. over the last 10,000 years) temperature has been stable overall but with many warm periods where the average temperatures were higher than at present.
- The earth warmed by 16oC coming out of the ice-age but has remained in a 3oC range ever since. We are now at the top of the most recent 1.5oC upswing.
- Biology has to deal with annual temperature changes of at least 10 times the long term average variation.
- Alpine records from 1780 show summer temperatures as broadly stable, with 7 hot summers occurring between 1780 and 1880, and another 7 between 1880 and 2006. Winter temperatures also show insignificant change. However, between 1960 and 2006 the winter minimum temperatures have increased by 3oC.
- Glacier growth/retreat is measurable and shows that the period from 800 to 1350 AD was much warmer in the Alps than the 1350-1950 period.
- Flood disasters are also well documented, and these show flooding was worse than now in the “little ice age” from 1300 to 1900 AD. In fact global data shows flooding is least when the planet is warmest.
- The “little ice age” was a bad time for humanity, the natural disasters being greater (deaths as a percentage of the total population) than over the last century.
- It is nonsense to say the return of malaria to Northern Europe is warming related. Malaria was always a problem in Northern Europe until swamps were drained in the early 20th century.
- Sea level rise is not sufficient to overcome the growth of the world’s river deltas. E.g. Bangladesh land-area is increasing by 20 sq km per year due to sedimentation.
So, attempting to reverse humanity-induced warming to return Earth’s climate to a pre-industrial state makes no sense biologically and the economic costs of such an attempt could prove disastrous. A warmer world will bring advantages to humanity not the least of which will be higher yields in agriculture and reduced energy consumption outside the tropics. Biological history suggests we should make the best of the present and save our resources to adapt to whatever changes occur in reality.
Bob Peoples of the American Chemical Society questioned the ability of the planet to meet the growth required to raise the living standards in China and India to that of the West. In 2010 China is expected to need 35% of the world’s iron ore, 30% of its aluminium, 25% of its zinc and 23% of its copper. China now emits more CO2 than the USA and is starting-up a new coal fired power station every week. Over the next 25 years, its oil needs will exceed those of the USA, and China will have built another 40 billion square metres of real estate, giving it a total of 60 mega-cities.
The environmental impact of supplying buildings, transport, water and food to the growing population is enormous and Mr Peoples argued that Green Chemistry could make a major contribution. The principles of Green Chemistry are:
- Minimise waste and maximise atom economy
- Design less hazardous chemical synthesis and safer chemicals
- Increase energy efficiency
- Use renewable feedstocks
- Use catalysts
- Avoid chemical derivatives
- Design degradable materials
- Avoid pollution
As an example, soy-based adhesives are formaldehyde-free, reduce air pollution by 90% in manufacture c.f. fossil-based adhesives, compete on cost and give better strength and water resistance.
Akihiro Omatsuzawa of the Japanese Chemical Fibres Association showed that Japanese manufacturing and mining sector index had declined from 110 to 69 over the year to Jan 2009, and within this fibre production had declined by 40%. Acrylics had suffered most (-48%) and cellulosics least (-9%). Monthly auto production had fallen from over a million in Oct 2008 to 481,000 in Feb 2009 but within this total, mini-car production was stable. Textile and clothing production indices had fallen from 100 in 2005 to around 65 at the start of this year. Exports to the USA fell by 16%. Energy conservation measures in the chemical fibre industry had nevertheless achieved the target reduction to 10% less than 1990 levels last year, ahead of the target 2010, and the sector now used half the energy per ton of product c.f. 1973.
Examples of Japanese eco-technology were:
- Air filters for reducing pollution from factories, incinerators and power stations, using aramids, PPS, polyimides, fluorocarbon fibres and others.
- Hollow fibre membranes for drinking water purification and for sewage treatment.
- Geotextiles for civil-engineering and asbestos-substitutes (PP and Vinylon) for concrete reinforcement.
- Use of biomass to replace fossil reserves for polymers.
- Development of environmentally sensitive composites
EU Fibres Development Strategy
Andreas Eule, President of CIRFS (soon to be renamed the EU Man-Made Fibres Association) reviewed the fibres scene:
- World polyester filament production was predicted to exceed 40 million tonnes by 2020, all but 6 million being produced in China, and less than a million tonnes outside Asia.
- World nylon filament will exceed 4 million tonnes, but here half will still be made outside China, and about a million tonnes will be made in the West.
- A slide of CO2 emissions per kilo of fibre showed cotton (5.6 kg), Acrylics (5 kg) Polyester (4.2 kg), Rayon (3.7 kg) and organic cotton and wool both at 2.2 kg. PLA potential was put at 1.7 kg by Cargill.
There were no pointers to the EU Fibres Development Strategy.
Biodegradable Technical Yarns
Christian Vieth of Polyester High Performance GmbH (Germany) first explained how PHP arose from the breakup of Acordis in 2003, and how it had recently been absorbed into another Acordis spin-off, Polyamide High Performance GmbH. So the initials stay the same but since March this year polyamide and polyester industrial yarns are from the same company in Wuppertal. Their new biodegradable polyester, Diolen® 150BT, is based on PLA made from glucose. It looks and feels like an ordinary polyester but has a much lower tenacity and much higher elongation. It was said to have “wool-like” properties, but otherwise no applications were suggested. It is heat-stable up to about 120oC, above which it loses out to PET yarns. Asked about its abrasion resistance, Mr Vieth said this remained to be done. Creep under load in the sun? – not tested but unlikely to be good. It would cost more than regular polyester, but not unrealistically more.
Spunbonded Cellulose Updated
Yuichi Komoro of Asahi Kasei Fibres (Germany) provided rare additional insights into the spunbond cupro-rayon process which has been making Bemliese cellulosic spunbonds for medical and clean-room applications since 1973. The cotton pulp has 3 times the DP of viscose pulp and is made into a very viscous dope by dissolution in cuprammonium hydroxide. This dope is wet-spun though >1mm (sic) holes into water flowing in a specially shaped tube which draws the filaments by 20,000-30,000% to achieve the final diameters of 0.3 to 13 microns with a high strength fibre. Coagulation of the cellulose occurs slowly from the surface by loss of ammonia from the dope into the water bath. The wet cellulose fibre is a gel with a microporous structure and very high water imbibition. Coagulation is not accompanied by dehydration and the final fibre does not have the skin-core structure of other cellulosics. As a consequence of this, the outside feels wetter than viscose at the same regain. (Dry viscose skin has 5% moisture, when its core has 13%, whereas Bemliese has a 13% content throughout. )
The continuous filaments are washed in water and entangled into nonwovens whose USP is purity and freedom from lint. Asked if traces of copper remained in the fibre, Mr Komoro said there were none, adding that this uniquely microporous cellulose was very easy to wash clean.
Biophyl™ from Sorona®
Colasanto and Bong of Advansa Marketing GmbH (Germany) observed that we have been using the world’s resources 1.3 times faster than they can be renewed and about 60% of all fibres used in apparel are made by energy intensive processes from fossil reserves. Biophyl™ on the other hand is made from Sorona®, Dupont’s poly trimethylene terephthalate (PTT) polymer which is made from terephthalic acid and 1,3 propane diol, the latter being synthesised by bacteria from sucrose. It has the character of a nylon fibre, but requires only two-thirds of the energy and generates two-thirds of the GHG’s. It processes like standard polyester, but can be dyed at temperatures 20-30oC below those needed for polyester. This leads to savings in dyeing equipment and energy amounting to 13%. It costs about the same as a good PA66 yarn.
Kazuhiro Morishima of Teijin Fibres Ltd (Japan) introduced Biofront™, a PLA fibre made without the technology developed by their recently acquired and later divested Natureworks LLC. Unlike the Natureworks PLA fibre, Biofront® is a stereocomplex of D- and L- lactic acids and achieves a much higher melting point (210-230C) and thermal stability than is possible with the Natureworks lactide route from blended D- and L- acids.
The new fibre is not easily hydrolysed and therefore not biodegradable. It can be blended with regular polyester and processed through dyeing and finishing under polyester conditions into all the usual polyester applications without problems. The main selling point will be the ability to increase the % renewable materials in labelling without any serious alteration in performance.
Grafting onto PP
Rolf-Dieter Hund of the Clothing and Textiles Institute at Dresden University (Germany) is attempting to improve the dyeing and finishing of PP by anchoring long-chain aliphatic amines in the amorphous regions of the outer layers of the fibre. Dodecylamine is applied to the fibre in a high-temperature dyeing process. The aliphatic chain enters the amorphous regions and is trapped there on cooling, leaving the amino group protruding from the fibre surface. The process takes 10-60 minutes at 80 to 130oC and, surprisingly, is said to have no effect on the fibre strength or crystallinity. The fibre is then acid-dyeable. The amine groups can also be used to bind organic nano-spheres to the surface; 0.3 micron polysorbitol- polyglycol methyl acrylate (PS-PGMA) spheres being illustrated on the surface of a fibre. The aminated fibre could also be coated with silver.
Lycra 2.0 tapes
Douglas Farmer of the Invista Applied Research Center (USA) described the heat-activated polyurethaneurea tapes that are gaining industry approval for bonding fabrics in garments to yield stitch-free and seam-free constructions. The laminates exhibit good peel strength over 50 domestic wash cycles and up to 300 washes in accelerated wash testing. Stretch and recovery properties are similar to woven elastic tapes but this is achieved without any additional thickness. Bonding needs 10 seconds at above 140oC. The main application illustrated were seamless “backsmoother” bras which could be invisible under a T-shirt.
Ali Demir of Instanbul Technical University (Turkey) has developed a bicomponent fibre with an incomplete PP skin on a sodium polyacrylate core. The PP sheath is spun as a C-shape and the SAP powder (Liquiblock HS Fines from Emerging Technologies) is injected into the slot using a patented process which ensures the SAP stays well below its degradation temperature. The current spinning machine has 6 holes and the final yarn is about 350 dtex with a composition of 95% PP and 5% SAP. When knitted into fabrics moisture regains of 12% - 30% can be obtained depending on the precise process used. These fabrics cannot be washed conventionally, and Air Wash cleaners apart, are destined for single use applications. Dry-cleaning removes about half of the SAP. In questioning, Mr Demir admitted the spinning process was rather dusty at 1000m/min and required optimising to trap the powder properly.
Axel Kolbe of TITK Rudolstadt (Germany) explained that antimicrobial fibres made by silver or copper treatment of lyocell during the washing stage suffered from the inability to make a white fibre. Furthermore, copper, unlike silver, is easily removed in any aftertreatments. Zinc polycarboxylate is white and can be added to the washing system, but it too is easily removed. So, TITK’s latest offering is obtained by adding zinc oxide or zinc sulphide to the spinning dope in high concentrations so that only about 5% of the resulting fibre is needed in blend to make a textile antimicrobial. Even then, if the textile manufacture involves bleaching, almost 50% of the active ingredient is lost. A further loss of 20% occurs during 40 domestic wash cycles but a satisfactory bacteria kill-rate (log3-4) remains. Asked how zinc contamination of the wash liquors affected solvent (NMMO) recovery, Mr Kolbe said it did not. Asked how the tensiles were affected, he wanted to discuss this privately.
Prof. Pertii Nousiainen of Tampere University of Technology (Finland) said the Biocelsol project is now part of Finland’s national biorefinery programme which has a €120M budget for research over a 5 year period. One of the objectives was nano-cellulose, normally obtained by refining pulp in an expensive process with low yield.
The Biocelsol process involves pre-degradation of woodpulp with enzymes to a point where it will dissolve in caustic soda. 50 enzymes have been screened and the currently used endo-gluconase is a commercial product. The resulting dope can be converted into fibres, films, casings, sponges and particles using equipment designed for viscose handling. The dopes are typically 4-6.5% cellulose dissolved in 7.8% soda to which up to 1.3% zinc oxide can be added to improve dissolution. Round section fibres have been spun at 76 m/min into a 15% sulphuric acid bath containing 10% sodium sulphate. This pure cellulose fibre has a water imbibition of 160%, a tenacity of 1.5 g/den and an extension of 18%: properties which make it an ideal fibre for disposables. Nanoparticles (200 to 300 nm) can be made by precipitation of the dope in acid with a precisely controlled salt content, and emulsions of these are natural film-forming binding agents for cellulose fibres. Biocelsol products are insoluble in the caustic soda from which they were made.
Cost and feasibility studies for a commercial operation are underway in both Finland and China. Biocelsol fibres can be made in viscose factory and yield a dramatic reduction in emissions.
Inflated Fibres Revisited
Walter Roggenstein, Technical Director of Kelheim Fibres (Germany), reminded us of their origins in Hoechst and Courtaulds and of their unique access to the technology portfolios of these once major fibre producers. As if to underline the versatility of the viscose process in general and the Kelheim factory in particular, he introduced 4 new variants in the space of 15 minutes:
Verdi – an alloy fibre with enhanced absorbency, enhanced dispersibility for wet laid nonwovens, and self-extinguishing flame retardant properties.
Bramante – A segmented pure cellulose collapsed hollow fibre giving high absorbency for tampons and nonwovens.
Dante – A hollow alloy fibre with ultra high absorbency, enhanced dispersibility and self-extinguishing properties
Bellini – A pure cellulose inflated-collapsed fibre with self-bonding characteristics for high quality papers.
Compared with regular rayon (Danufil®), both Verdi and Bellini gave a 50% increase in Water Imbibition, Bramante doubled it, and Dante more than trebled it. In tampons, the Syngina benefit of Dante was an impressive 50% over Danufil. Unlike Danufil, all the new fibres could be wet-laid in 100% form, with Dante and Bellini giving useful tear strengths, the latter twice that of a writing grade paper.
Asked about fibre tensiles, Mr Roggenstein said these were lower than Danufil, but more than adequate for the nonwoven and paper markets for which they had been designed. They would be available in a normal range of fibre sizes (down to 0.7dtex) and a 0.5 dtex version was under development.
Matthew North, Commercial Director of Kelheim Fibres (Germany) reviewed the influence of viscose fibre cross-section on fabric performance and comfort. In particular, the flat crennelated section of Kelheim’s Viloft® fibre, when twisted during yarn production, traps more air in the yarn than other fibres and thereby improves the moisture management and thermal performance of fabrics made from it. Using microscopy linked to the Zeiss AxioVision software, the air content of a range of blends of Viloft® with other cellulosics was measured to demonstrate the benefits arising from the use of Viloft®. The same fabrics were then tested at the Hohenstein Institute for pilling, thermal properties, water vapour permeability, absorbency, and perspiration buffering. 100% Viloft® outperformed the blends for pilling, thermal properties, and WVP while matching micromodal for absorbency and perspiration buffering. 100% Viloft delivered the best overall thermophysiological wearer comfort for the range tested.
Eammon Tighe of Natureworks – no longer a JV between Teijin (who are launching their own version of PLA) and Cargill – described again how they were continuing to improve their eco-profile by looking for reductions in process greenhouse gas emissions. In addition to previously provided information, the corn used is now animal-feed grade, and cellulose to PLA processes are being developed.
Natureworks PLA capacity has now been raised to 140,000 tonnes/year, of which 75,000 tonnes is being sold. 70% of this goes into packaging, the rest fibres. Products made from fibre now include spunlaid teabags for Unilever and Tetley (Ahlstrom) and spunlaid ADL for Huggies Pure and Natural (Kimberly Clark). Toyota is using it in carpets for the Prius, and the polymer is now used in one layer of the Frito Lay and Sun Chips bag film. Additives blended with PLA has improved processability. (Eco Flex from BASF, CPL01 from Polyvel for increased hydrophilicity, and Cesa Extend from Clariant were mentioned.)
The Ahlstrom spun-laid investment is a 40m euro lightweight Reicofil line capable of making very uniform 15 gsm PLA tea-bag “paper” for the Pyramid bag which used to be made from lyocell paper. Interestingly Natureworks no longer recommend composting as a disposal route for PLA. Recycling is the main option, with Galactic (Belgium) now hydrolysing fibre back to lactic acid.
Natureworks is looking for a site for the next factory, definitely outside the USA, maybe in the EU or Asia. A decision will be made in 6 months to allow a factory start up in 2013.
Reinhold Rothenbacher of Kelheim Fibres (Germany) reviewed the evidence in support of the flat, crennelated viscose fibre (Viloft) being a better basis for flushable wipes than regular rayons. In essence, hydroentangled Viloft nonwovens break up faster in the tube-test than regular rayons made under identical conditions. Mr Rothenbacher noted that Viloft gives nonwovens one-third weaker than regular rayon when entangled under identical conditions, but when regular rayon is entangled to this lower strength, it exhibits unacceptable surface cohesion. When short-cut Viloft is wet-laid, it gives denser structures with higher wet cohesion.
Microfibre webs from Centrifugal Spinning
Martin Dauner of ITV Denkendorf (Germany) observed that centrifugal spinning is turning out to be a more productive route to submicron fibre webs than electrospinning. ITV's collaboration with Rieter on adapting the Center Bell centrifugal varnish sprayers to microfibre production has now reached the point where a first order for a commercial line is expected later this year.
While meltblowing is now entering the same territory with thermoplastic dopes, centrifugal spinning works best with solutions of polymers. 3 Center Bell heads are needed to cover a metre of width with 0.1 to 0.7 micron filaments. Polymer solutions processed include cellulose acetate, polyamides, PLA's, collagens, PVA's, polyurethanes, peptides, aramids and PAN. Electrostatic charging of the filaments is used as well, but only as an aid to web collection. Potential applications mentioned were filters of all types, wipes, battery separators, fuel cells, comfort clothing, medical - barrier materials, and supports for tissue culture.
Greenfil Bio-synthetic Fibre
Eric Grosjean of Sofila (France) introduced a castor oil based fibre which had been developed in a cooperation with Arkema who make the polymer and Radici who spin the yarn. Arkema had been making the polymer since the 1930's for other uses and the new Greenfil fibre is a polyamide 11 made without recourse to fossil-based monomers. Castor-oil plants grow with minimal water, fertiliser and pesticide use, on poor soil. Radici are making microfibre and fine-count continuous filament yarns (e.g 78 dtex/30 filament) for high value textiles. The polymer has a density of 1.04 g/cc and an abrasion resistance comparable with nylon. It dyes like nylon and the fabrics made from it feel cool to the touch. It is also naturally bacteriocidal “being a polymer of an amino acid used in cosmetics”.
Dr Bas Kris of Applied Polymer Innovations (Holland) introduced API as the new name for the old Diolen Industrial Fibres R&D lab in Emmen. They have expertise in most industrial polymers and their conversion into yarns, and one of their current projects is finding new uses for PLA yarns. So far they have prototyped:
- A knitted support netting for grass turves on roll, the support ultimately biodegrading in the soil.
- Temporary carpets for exhibition stands.
- Woven banners for promotional displays.
- Compostible artificial grass, where PLA is both the grass and the backing cloth. Here the PLA is blended with a copolymer to improve its resilience.
Active Carbon Filters
Akishige Kimura of Toyobo (Japan) described how the unique porous structure of active carbon fibre allows it to outperform granuated active carbon in adsorbing volatile organic compounds from industrial processes. GAC has macro-, meso- and micro-pores, but only the micro-pores adsorb. Furthermore GAC needs large and costly adsorber vessels and regenerating it is costly and time consuming. The active carbon fibre in Toyobo's K-Filter has a much higher specific surface than GAC (1700m2/gm c.f. 1000m2/gm) arising from its micropore-only porous structure. It is a more controllable adsorbent than GAC because it adsorbs faster and more completely and has a sharp cut-off when fully loaded with VOC. The result: 100 kgs of the fibre can do the job of 1320 kgs of GAC, removing 99% of the VOC's where the larger load of GAC only removes 80%. Regeneration of the fibre needs 200 kg/hr steam where the GAC needs 360 kg/hr.
While the K-Filters have been used commercially with gases for many years, a new version suitable for water purification is just about to be commercialised. This will be capable of removing organic compounds (e.g IPA) from water at high efficiency. Asked which carbon fibres were best, Mr Kimura said pitch gave the best yield of carbon but these fibres are too weak for filters. Cellulose or PAN-based fibres were carbonised and then activated, a process which opens the closed pores in the carbonised fibres.
Durable Hydrophobicity by PECVD
Merce de la Fuente of LEITAT (Spain), a technological research centre for textiles, discussed ways of making polyester more hydrophobic. Plasma-enhanced chemical vapour deposition achieved hydrophilicity when acrylic acid or acrylamide precursors were used. Fluorocarbon nanocoatings with high wash fastness have also been obtained by a 2 stage plasma process: a first stage of activation and a second stage of plasma polymerization of fluorocarbon monomer:
• The morphology of the Fluoro Carbon nanocoating depends on the activation
gas: for air plasma activation smooth FC film is obtained while for argon
plasma activation, FC particles are generated.
• The Wet Contact Angles show that the smooth FC film confers the best water repellence with 138º.
• Unexpected WCA values were observed for the oxygen and argon plasma
activated samples: the WCA values increase with the number of wash cycles.
• These unexpected WCA's are in agreement with the SEM images: in argon
and oxygen plasma-activated samples, FC particles deposited onto fibres were observed. These particles are the reason for the increase in roughness and the higher WCAs.
In response to questions, low pressure plasma was used, and wet contact angle tests were the only wettability tests carried out so far.
Bicomponent Fibre Developments
Hans Koslowski of Deutsche Fach Verlag (Germany) reviewed the history of bicomponent fibre technology and markets commencing with their development in the 1930's by IG Farben to increase viscose crimp and make wool-like fibres. According to a patent survey, development activity had peaked in the 1960's (45 patents) declining to 11 patents in the 1990's, and recovering to 14 patents in the first 6 years of this decade. In 2007, world production of bico fibres was 236,000 tonnes, 80,000 in Japan, 81,000 in other Asia, 40,000 in the USA and 35,000 in Europe. Ana Ribeiro of CenTi (Portugal) in partnership with Hills Inc (USA)is using high melting point polymers in bi- and tri-component fibres. Their new Hills Inc. pilot plant is capable of operating up to 450oC with “agressive and corrosive” melts and features a melt-handling system which minimises polymer residence time and dead spots to minimise degradation.
Processable polymers mentioned during the talk included:
- Fluoropolymers, PVDF and PTFE
- Polyetherether ketone (PEEK)
- Polyphenylene sulphide (PPS)
- Polyamide imide (PAI)
- Liquid crystal polymers (LCP)
- Carbon based conductive polymers.
Applications under development were:
- 20% PEEK on a PET core (PEEK performance at lower cost)
- 5% LCP on a PET or PP core.
- Dielectric skin on a conductive core for sensor/actuators
- Tricomponent fibre with a conductive core, piezoelectric middle layer and a conductive skin for “processing of fibre devices”(?)
The conductive fibres had deniers of 200, 500 and 1000.
The Market for Nano.
Mutlu Sezen of Korteks (Turkey) appeared to define nano broadly enough to reach the conclusion that the market in 2007 was $147 billion. By 2015 it would be $3 trillion and amount to 15% of global production. Nano would be a second industrial revolution to change the prospects of the business world. Miscellaneous data included:
- EU funding for nanotechnology had been $1 billion between 2002 and 2006
- US Government funding amounted to $1.5 billion, and total US nano R&D funding was $3 billion (per year?)
- By 2015, 12% of all jobs in manufacturing would be in nanotechnology
- The EU market for nanotechnology in textiles would surpass 100 billion Euros by 2010 and had the potential to reach a trillion euros.
Piotr Kulpinski of the Technical University of Lodz (Poland) has been electospinning from 5 nozzles to make webs at 0.5 gms/hour. He had started with cellulose acetate and moved onto dilute NMMO solutions of cellulose which were electrospun onto the surface of water in which an earthed electrode was submerged. Some webs appeared to be films with a fibrous pattern on the surface, others were spun into yarns. One slide illustrated a ball of wet nanofibres with a water imbibition of 1000%.
Microstructured Fibre Surfaces
Marcel Halbeisen of EMPA Materials Science and Technology (Switzerland) has shown that diffraction and interference patterns engraved on metal rollers can be embossed onto fibre surfaces to give rainbow and sparkling effects and even colours without dyeing. On PP serious flattening of the fibre occurred, but on a PE/PP bico the results were better. The best results were with amorphous polymethyl methacrylate fibres.
Nanotechnology for Textiles
Isabel de Schrijver of Centexbel (Belgium) promoted Centexbel (an EU technical institute) and gave a general introduction to nanotechnology. Centexbel were using plasma treatment, sol-gel treatment and electrospinning to try and alter the surface of textiles permanently by attaching “nanoparticles”. The list of nano-possibilities seemed endless and included metals, metal oxides, clays, bucky-balls, fullerenes, polymer emulsions, mayonnaise etc. Properties claimed included FR, hydrophobicity, hydrophilicity, improved strengths, barrier to gases etc.
Making Multifunctional Textiles
Antionio Viera of CENTI (Portugal) took us on another whirlwind tour of his institute's capabilities in surface engineering and nanocoating. Buzz-phrases included atmospheric plasma, plasma pretreatment, plasma enhancement with enzymes, nano-scale, nano-film, nanoclay-particles, in-line monomer and oligomer deposition, e-beam polymerisation, sputtering, superhydrophobicity from nanoroughness and low surface tension, thermal mannekins, FTIR, TGA, DSC, DMA, AFM, CFD, USW. Synergy between academia and industry was among the objectives.
Improving Air Filters
Yvette Dietzel of STFI and Sabine Amberg-Schwab of the Franhofer Institute (Germany) were trying to develop new coatings to enhance the performance of air filters, e.g by increasing the lifetime of electrets. Different water-based inorganic-organic hybrid polymers (e.g bifunctional silanes) were used to functionalise filter media intended for dust-loaded air in buildings and cars. They claimed a combination of different properties, e.g electrostatic, antimicrobial, and stiffening could be obtained with one coating system. However it appeared that the stiffening of the high loft samples was unacceptably high; a plethora of confusing data slides leaving the impression that little filtration improvement had been obtained. In dealing with questions, the statement, “the coatings do not influence filtration negatively” appeared to be a fair summary.