Walt Disney World in general and the on-site Hilton Hotel in particular were unusually quiet in the aftermath of September 11th. Nevertheless some 450 delegates enjoyed this major event in the annual nonwoven calender, about 220 fewer than had gathered a year ago for the Toronto Insight 2000. According to conference organiser Jim Hanson of Marketing Technology Service Inc., registrations for Orlando had been set to equal or beat the Toronto record up to “911” but after the tragedy, new registrations and cancellations had been roughly equal.
Pricie Hanna, VP of John Starr Inc reviewed the effects of major acquisitions, internal expansions and new market entrants on the disposables market and its supply chain.
- Wal-mart’s acquisitions of Woolco in Canada, ASDA in the UK, Cifra in Mexico, Wertkauf and Spar Handels in Germany, along with their expansions into Brazil, Argentina, Puerto Rico, China and South Korea were increasing the competitive intensity. (Their “everyday low price” philosophy was spreading.)
- In 1994 the $738 million sales of private label diapers went 61% through food stores and 28% through mass merchandisers. Last year the $756 million sales were 39% through food stores and 52% through mass merchandisers. (Drug stores account for the remainder.)
- Wal-Mart’s “White Cloud” diapers gained share rapidly being better value than P&G Luvs®
- Between 1995 and 2000 P&G has fallen from 36% to 34% global market share of diapers and training pants. The biggest percentage loss was in Latin America (39% to 23%). Their strategy is to expand premium product globally, to hold the category leadership in core brands e.g. Luvs with cloth-like backsheets, and to rely more on suppliers for new developments.
- Over the same period, KC grew from 19% to 28% of the global market, with the biggest gains in Western Europe (4% to 19%) and Latin America (23% to 32%). Their strategy is to grow by acquisition (e.g. Linostar in Italy, Mimo in Chile, SK in Taiwan).
- Paragon, Ontex, SCA, and Kendall-Confab are capitalising on the growth of store brands, Paragon by adding new capacity and Ontex by numerous acquisitions.
- SCA has acquired J&J’s Serenity® (inco-pads), and Hartmann has acquired Vlesia® from DSG. DSG has acquired Drypers. Unicharm and Kao are consolidating.
- In China, Hengen International is investing in new femcare and diaper lines and has imported a new incontinence product line.
- Other local producers to watch: Everbeauty and FuBurg in Taiwan, CMPC in South America, and Grupo P.I. Mabe in Mexico, South America and Spain.
Among the suppliers
- Avgol has acquired Unifi
- BBA and PGI are rationalising
- BBA and First Quality are installing new coverstock lines.
- Elastic composites are emerging from KC, Clopay, Tredegar, BBA, Dupont.
- Superabsorbent foams are emerging from BASF, Freudenberg and P&G?
- Fluff pulp producers are focussing on air-lay expansions
In response to questions, Ms Hanna felt that
- In a recession, hygienic product consumption is unlikely to fall, but cheaper products would gain share and penetration of new markets would be more difficult.
- Store brands would do particularly well.
- Raw material prices would stabilise.
- Could the necessary R&D be afforded? It had to be well focussed, and if suppliers were to contribute to innovation, they had to be given more information. (Still too much secrecy)
- Suppliers are indicating that new product developments are not being taken up as quickly as converters had promised.
- Air-laid diaper cores are still a couple of years from reality, but the price gap is closing. They could be specified for new diaper line installations where capital costs could be reduced by the adoption of air-laid.
- Apart from some regional issues, SAP supply and demand is likely to be in balance for the next 3 years.
- There is no sign of a successful interlabial pad from P&G.
- Market analysts holding CEO’s of public companies accountable for short-term growth would give the small private companies the edge in the longer term.
Linda Kelly , who joined the Starr consultancy this year after managing a business group at BBA Nonwovens, presented John Starr’s paper.
- Nonwoven industry revenues had grown from $3 billion in 1980 to $10 billion in 2000 and were expected to reach $18 billion by 2010.
- Revenues from the top 10 producers of nonwovens had risen from $3 billion in 1990 to $5 billion in 2000 and would reach $10 billion by 2010.
- EBIT (Earnings before interest and taxation) as a percentage of revenue, while static over the last 20 years would rise from about 13% to 15% for the industry as a whole and from about 14% to 18% for the top 10 nonwoven producers.
- The hygiene market now consumed 3 to 3.5 million tonnes of pulp, 1.2 million tonnes of superabsorbents and 0.5 million tonnes of barrier film.
- 40 billion square metres of nonwovens were used in combination with the above materials and a further 3.5 billion square metres in the heavier weight hygienic wipes category.
- 266 billion absorbent “pads” were used in 2000 growing to 310 billion by 2004. (Diapers accounted for 100 billion of the 2000 figure, the remainder being femcare and incontinence products)
- Retail value of the pads in 2000 was $40 billion.
- Total wipes retail value was put at $3.5 billion (86 billion units) in 2001, expected to rise to 101 billion units by 2005.
- 1.1 million tonnes of spunbonded PP is now produced. Some overcapacity exists and obsolete machines will be closed or modernised. However more capacity is needed for some types in some regions.
- Carded thermal bonded coverstock has lost share globally but is now replacing some apertured films in Asia based on better cost performance.
- Femcare accounts for 80% of current air-laid production. More usage can be expected in femcare and incontinence pads, with some introductions in training pants and diapers.
- Hydroentanglement capacity was estimated to be 300,000 tonnes (2000?)
Industry profitability was thought to have declined recently due to overcapacity driving down prices, investments in new technology and the slower than expected introduction of new products.
Future growth would arise from:
- Elastic fabrics
- Bico and microfibre fabrics
- Apertured fabrics
- Lighterweight SMMS materials
- Airlaid cores
Asked if this last list was in order of likelihood, Ms Kelly said it was. New product introductions had been slowed by both KC and P&G over the last 2 years. (New capacity had been installed to produce them but the expected take-up has not occurred.)
Sorin Crainic, Product Development Group Manager with PGI Nonwovens described a global study of personal care products. This involved categorising the products, noting the main claims made for them, the properties yielding the claims, the technologies used to deliver these properties, and hence the trends in the use of these technologies.
In Hand & Body Wipes:
- Cellulosic fibres were needed to retain lotion or remove moisture from the skin, whereas the synthetics improved bulk and assisted lotion release.
- Air-laid technology dominated the US scene, but card/spunlace dominated in Europe and the Far East. Wet-laid is used for economy products.
- Specialities include antimicrobials, skin care agents (vitamin E, Aloe)
- Flushability is in demand, but true nonwoven flushability (as opposed to tissue or flushability by virtue of small size) has yet to appear.
In facial cleansing, moisturising and make-up removal wipes:
- Rayon and cotton were needed for softness, woodpulp for exfoliation.
- Card/spunlace dominates for softness and lint-free properties
- Embossing or 3D aperturing (Miratech®) provide the structure for exfoliation, while lamination to harsher (woodpulp) products provide the abrasion.
In facial treatment wipes:
- Synthetics (esp polyester) provides strength and lotion release; rayon or cotton provide softness.
- Card/spunlace again dominates but card/thermal (using rayon and PP) technologies can be found.
- Polyester spunbond is used in nose-strips
- PP film is used to absorb skin-oil (J&J’s “Clean and Clear”)
In response to questions, Ms Crainic observed that:
- The baby wipes market is approaching saturation and will peak by 2005-2007.
- Lotion application, especially sun-tan lotions, are a growth area.
- Flush-by-size disposal is likely to be stopped by the authorities: sewers are blocking slowly due to accumulating nonwoven hang-ups. (Wet-toilet tissues were less of a problem.)
- Baby care wipes now dominated the personal care sector, but in future all the other personal care wipes combined would provide a market equivalent to baby-care.
- The next new technology: developing more complete lotion-release.
- Most patents were now on flushability, but inventions relating to interactions between nonwoven and lotion were now appearing.
Phillipe Coppin (Consultant) updated his Insight 1998 paper and provided a detailed analysis of the publicly available information:
- Global production in 2000 was estimated to be 246,000 tonnes excluding pilot lines, cosmetic pads and “textile” lines (PGI’s Apex®, Freudenbergs Evolon®)
- By the end of 2002, output from an additional 22 new lines will be added, and some output will be lost from the closure of old lines.
- Once again the new lines are mainly destined for the European area with Orlandi, Technofibra, Jacob Holm, Tenotex, Freudenberg, Novita, Spuntech, and 5 undisclosed Fleissner lines being mentioned. (includes Turkey, Israel and Egypt)
- New US installations will be at BBA, Dupont and Ahlstrom.
- New Asian installations will be at Daiwabo, Unitika, Nisshinbo, and Baiksan.
- In Mexico, Polymeros y Derivados are adding a second line.
- In South America Uniminas, Ober, Dupont/Cipatex and K-C Columbia were mentioned.
The growth of the technology has been fuelled by an explosion of wipes offerings following the successes of P&G’s baby wipes and Swiffer® products. New lower-cost, higher quality systems from both Perfojet and Fleissner have contributed to the early obsolescence of the older machines. The large impregnated wipe market is still dominated by air-laid but could turn to spunlace if one of the majors decides that such fabric would confer a marketing advantage.
Roll-goods prices of spunlace (summer 2001) ranged from:
- 11-12 c/yd 2 for a 55gsm 50/50 rayon/pulp wipe material, through
- 14-15 c/yd 2 for the 70/30 rayon/PET version
- to 22-30 c/yd 2 for 80/20 rayon/PET at 68-80 gsm for a food service wipe.
- Swiffer® fabric, a 68gsm carded PET/PP Scrim sandwich was 20-22 c/yd 2.
- Surgical barrier, the hydrophobic 68gsm 45%/55% PET/woodpulp material, was selling at 30-40 c/yd 2
- For comparison, 100% latex-bonded air-laid pulp wipe fabric cost 10-11 c/yd 2.
Capital Costs for a 3.5m card/hydro line running at up to 170m/min were estimated to be $7.7-9.0M with an additional $4-5M being needed if an airlaying option was required. Production of card/spunlaid composites (e.g. for Swiffer®-type dry wipes) would require an additional $6M for the spunlaid PP extrusion equipment. (Both the airlaid and spunlaid options were costed at 200m/min.)
In the textile market, both PGI’s Miratech® and Freudenberg’s Evolon® were having difficulty selling against woven products and were adding little to the overall growth as yet. Miratech® was selling into garden furniture covers at K-Mart while Evolon® had some success in reusable wipes. BBA had licenced their Interspun® hydroenhancement system (for bulking up woven fabrics or stabilising knits) to CULP Inc. for upholstery and ticking uses. Fleissner, under an exclusive agreement with BBA on this technology (Aquatex®) had installed the 2.5m CULP line.
One “novelty” mentioned: the patent issued to Paul Zlatkus in June 2000 covering the production of elastic fabrics by hydroentanglement of woodpulp into a pre-stretched foam.
Air-Laid: The next wave
John Conley (Consultant: formerly founder and CEO of Airformed Composites and President of Walkisoft) reviewed the potential of air-laid nonwovens:
In diaper cores he saw air-laid providing improved performance and comfort in use while having the capability to reduce conversion costs through higher productivity on simpler diaper lines. There was a 1.8 million tonne/year potential market here but to realise it costs had to be further reduced to persuade diaper makers to convert and install machinery to handle it. Festooning systems to handle the cores appeared to be a commercial reality but again, further improvements were needed.
In wet toilet tissue, the latest products from P&G and KC were in fact successors to Playtex “ Better Way” (tissue - ‘70’s), American Can “Fresh’n” (air-laid – ‘70’s) and P&G’s “Certain” (tissue - ‘80’s). The main lesson from these early failures was that a massive marketing spend was needed to persuade consumers to try and then regularly repeat-buy the product. Mr Conley nevertheless predicted a 45-70,000 tonne market for air-laid in this category by 2007.
Impregnated wipes were an $835M market in the US and Canada in 2000 and could be expected to reach $1.5B by 2005 due to globalisation of the US products and many new applications being developed (dry shampoo towels mentioned).
In packaging he expects the air-laid tonnage to reach 300,000 per year by 2010. The products involved:
- Meat and poultry pads
- Repulpable boxes with soft interiors
- Dessicant wraps for electronics and pharmaceuticals
- Blood transport absorbent packs
- Biocidal biohazard and medical waste packs.
- Controlled release carriers for high-value produce.
Other applications expected to grow were:
- Trans-dermal patches and wraps
- Graduated filters (porosity gradient)
- Water dispersible film-airlaid laminates
- Spunbond/airlaid/Spunbond laminates that can be split to yield two soft and durable sheets. (Garment labels?)
- High modulus fibre air-laids for reinforced composites.
- Heating/cooling pads and wraps.
- Carbon/glass airlaids with special binders for “warm” fuel-cell stack plates (50,000 tonne mid-term potential!)
Mr Conley observed that the original American Can “dry-papermaking” air lay machine reached 1350 ft/min compared with the 550 ft/min achieved after 25 years of development on the current M&J and Danweb systems. Higher speeds coupled with waste reduction and the ability to use low-cost reclaimed fibre buried in the centre would finally get air-laid costs to an acceptable level.
In response to questions, air-lay diaper cores were now going commercial, but he was not at liberty to say who was doing it. Why not use tubs (as in Europe) for wet toilet tissue? To minimise the change of habit c.f. dry tissue. However wet tissue was expected to be incremental volume over dry, and not a replacement for it.
Jesper Dobel, General Manager of Dan-Webforming International ( Denmark) described initial trials with a new forming head said to be capable of laying up to 40mm fibres and competing with carding and crossfolding. His goal was to engineer a technology that could be integrated with either Dan-Web or M&J lines feeding spunlace bonders and which could produce webs with equal MD and CD properties from 100% man-made fibres.
Problems with the fibre feeders/openers which had yet to be adapted for the longer fibres meant that results to date were from 6, 8, 12 and 24mm (maximum), and a video showed 18mm fibre running at ~10 m/min from ~12” wide head, the internal details of which were not revealed. Photos of the webs indicated that while 12mm looked excellent, 18mm was borderline and 24mm, while being a remarkably good web for an air-layer, was not up to carding standards.
- Today’s pulp-forming speeds were said to be 400m/min, with 800m/min expected by 2005. (Throughput was expected to rise from 400 to 600 kg/hr/m in the same period)
- The new head allowed 85% of peak (pulp) productivity with 18mm fibre compared with only 5% on the current Dan-Web formers. 80% was achievable with 24mms, a length which would not run at all on the old machines.
- The fibres tested were 2.2dtex Trevira polyester with “slight” crimp.
- Line speeds possible on the 18mm were low at around 25m/min at present. 200m/min was felt to be achievable.
- Throughputs were 150 kg/hr/m but doublel this ought to be achievable.
- The new head was patented in August and could be commercially available by next Autumn.
- They hoped to install a head on one of their 600mm pilot lines next.
Bodil Engberg Pallesen of the Danish Agricultural Advisory Centre and Marianne Eriksen, a consultant, described a new air forming unit capable of processing flax and hemp into thick insulation “slabs” to compete with glass and mineral wool building insulation. Although the internal details were not revealed the forming head was not unlike a Dan Web machine without the cylindrical screens.
- The 60 cm wide line would convert 600kg/hr of a flax/bico mixture (95/5) to make a thermally bonded wadding up to 20cm thick.
- This was water-jet cut into 60x90cm blocks for packaging.
- For building insulation, flame retardency will be achieved by adding 4-8% of sodium silicate, but this cannot be done on the current line.
Other applications envisaged are:
- Pipe Insulation
- Growth media (Peat can be air-formed)
- Composites – these would use up to 50% of the bico fibre and be compressed.
Costs are about half the costs of other European hemp and flax products because other processes use cards and require more binder.
Marsha Seekins, Commercial Services Director of Georgia PacificCorporation reminded us that fluff-pulp once provided absorbency in diapers, but is now a fluid-distribution system for superabsorbent powders. Had superabsorbents not penetrated the diaper market, diapers would have needed 6 million tonnes/annum of fluff by now. In reality the 3.33 million tonne total market was split as follows in 1999:
- Diapers:1.635 million tonnes
- Femcare: 0.796 million tonnes
- Adult Incontinence: 0.654 million tonnes
- Air-laying: 0.247 million tonnes
North America and Western Europe are the big users with 25% each, China and Eastern Europe combined amount to 23%, Latin America uses 8% and the Middle East 5%.
Of the product sectors, only AI (6% pa) and Airlay (8.5% pa) showed reasonable growth. Nevertheless GP’s projections indicated that a further 500,000 tonnes of fluff capacity would be needed by 2004. As it happens, GP have a 1.3 million tonne fluff capability, of which 0.8 is currently making for the fluff sector. The Brunswick plant is in the process of switching 100,000 tonnes of bleached board capacity to fluff. (60,000 have already been converted and the rest follows next year.) They now see fluff as a speciality product rather than a commodity and are concentrating on “flawless execution of the basics” while building relationships with, and providing exceptional quality and service to, customers. In response to questions Ms Seekins said:
- Loblolly Pine is better for fluff, eucalyptus is better for tissue. (Coastal Slash is another excellent wood for fluff.)
- Hardwoods are hardly used for fluff.
- They are beginning to see some separation of fluff and market pulp pricing.
- SAP’s will always need something to distribute fluid: pulp is best
- The most common technical service issue is defibration, hence the development of debonders.
Craig Poffenberger a Senior Scientist with the Goldschmidt Chemical Corporation introduced Arosurf® PA777 and Z-Quat® at last year’s Insight conference. Since then, the PA777 has been tested by pulp producers and generated a wide range of results. It has now been reformulated to better balance absorbency/ease of defibration/strength loss by the addition of a hydrophilic compatible with the imidazolinium. Mr Poffenberger concludes that debonders need to optimised for each type of pulp to get the maximum vertical wicking performance. The new blend is now commercial, but there is no data on how it’s properties changed with time after application.
Z-Quat® remains at the developmental stage and “continues to wind its way through the regulatory registration labyrinth.”
Ray Miller, Technical and Business Manager of Dupont Bio-Based Materials described Dupont’s biotechnology strategy and their commitment to earning 25% of revenue from businesses not needing depletable raw materials by 2010. Furthermore, in the same year they expect to derive 10% of all energy needs from renewable resources. The introduction of Sorona™ fibre, based on PDO (1,3 propanediol - currently derived from propylene) and terephthalic acid was part of this strategy because they were planning to switch to bacterially-derived PDO in the near future.
In nature, a yeast converts sugar to glycerol, which can then be metabolised by a bacteria into PDO. In partnership with Genencor and Tate & Lyle, Dupont has developed a single bacterium to do both steps and is now starting up a pilot line to make 100,000 lbs/year of PDO by this method. The decision on whether or not to switch Sorona™ from the propylene-based to the corn-based PDO will be taken next year.
Recapping on the properties of the Sorona™ fibre, which can be regarded as filling the gap between elastomers and hard fibres like polyester:
- Elastic with good stretch recovery
- Very soft handle
- Easily printable and atmospherically dyeable
- Radiation sterilisable
- Inherently stain and UV resistant
- Meets Class 1 Flammability standard
The fibre will initially cost about 50% more than polyester, but is expected to come down to a 10-15c/lb premium over polyester as volumes increase. Existing polyester production plant can be retrofitted to enable Sorona™ production if need be.
Polymerising the PDO with monomers other than TPA can make other fibre types, including a true thermoplastic elastomer. In fact the current Sorona™ fibre carries the designation 3GT, the range of fibre possibilities being indicated by the 3G”X” suffix. A toughened polymer for speciality resins is also under development.
Bill Haile, a Research Associate with Eastman Chemical Co. updated the information on the Eastar Bio® copolyester derived from PTAT ( a poly tetramethylene adipate-co-terephthalate made from adipic acid, terephthalic acid and butanediol). The polymer can be melt-spun into binder fibres and nonwovens, the fibres being capable of forming strong elastic bonds with cellulosics and other polyesters.
6 denier unicomponent fibres have been spun at 1500 m/min from an extruder at 160-170 oC. They are hard to card due to their elasticity and bicomponent versions with a PTAT skin on a PP core is likely to be the better option for staple nonwovens. Bicomponent fibres with a biodegradable core such as PLA are under development.
Results from trials at TANDEC using 50% and 30% of the PTAT/PP bico to bond cotton were presented. 5% to 20% of the unicomponent fibre has also been blended with flax, needled and static hot-pressed into flexible sheets. Similar blends of short-cut unicomponent fibre with woodpulp in papermaking demonstrate improved wet-strength after calendering, 10% fibre addition giving a 50% wet-strength boost.
PTAT fibre biodegradation rates compare favourably with Kraft paper in most tests.
The polymer is already commercial in film products, and spunbond nonwovens using it are expected to appear next year. Eastman will concentrate on polymer sales and will not produce either fibres or nonwovens.
Mabrouk Ouederni an Engineer with KoSa provided data to illustrate how polyester could give improved fluid management in air-laid nonwovens. He had tested 10% to 40% of 6mm polyester with solid and hollow sections, in deniers from 3 to 15, in blend with 48% to 70% of a standard fluffpulp, all samples being thermally bonded with 12% of Kosa T255 PE/PET sheath/core bico fibre. The conclusions:
- Crimp level and fibre finish has a significant effect on throughput. A 25% throughput benefit can be obtained by optimising these parameters at a 10% PET addition level.
- Hollow fibres give ~25% higher throughputs than solid fibres.
- At 6mm, the denier had little effect on througput.
- Web thickness increased from about 0.5 to about 0.8cms under a 25lb load when polyester was added. Under no load there was no thickness change. Hollow fibres gave more bulk still.
- 10% polyester improved recovery from compression, increasing total free absorbency from 76 to 86 gms.
- Acquisition rates increased from 2ml/sec to 3 ml/sec for solid PET, and on to 7ml/sec with hollow fibre addition.
- In a leakage overflow test the hollow fibre allowed a 7 ml/sec insult rate without overflow.
- Wet strength of the air-laid increased from 40 to 60gms with 10% PET addition.
In answers to questions, hydrophobic finishes can be used on the PET; there was no data on cost benefit of PET additions, and no data on static issues with hollow polyester.
Jayesh Doshi, President of eSpin Technologies defined nanofibres as having a diameter less than 100 nanometres and described his work on making such fibres for filtration applications by electrostatic spinning. Nylon polymer from Dupont, dissolved in formic acid and contained in a hypodermic-like syringe had a high voltage applied to the needle. As this voltage discharged through air to the earthed conveyor, it pulled a jet of solution from the capilliary tip. This jet became unstable, fragmenting into many fine filaments (forked lightning?) as the solvent evaporated prior to grounding on the conveyor. Filaments with diameters in the range from 22 to 122 nanometers were obtained in web form on the conveyor.
Selected results from some of the trials to date were presented. When 17 gsm of nanofibre webs were combined with conventional PP spunbond (20 micron diameter fibres at 20-40 gsm) they:
- reduced air permeability from 350 to 1 cfm.
- Increased hydrostatic head from 6 to 8 mbar
- Increased fabric thickness from 0.36 to 0.54 mms
- Increased filtration efficiency from 28% 99% (0.1 micron NaCl aerosol)
When 8gsm of nanofibre webs were combined with conventional PP meltblown (2-5 micron fibres at 94gsm) they:
- Reduced air permeability from 49 to 2 cfm
- Increased oil absorbency from 1450 to 1690%
- Increased fabric thickness from 0.91 to 0.96mm.
- Increased filtration efficiency from 40% to 96%.
There were numerous technical challenges to be addressed:
- Health hazards related to solvent vapour and fibre particle inhalation.
- Fire and explosion risks due to high voltage and sparks
- Packing, shipping and handling issues
In response to questions Mr Doshi said he was in the process of getting financing from Silicon Valley for a larger scale plant capable of making 500-1000yd rolls or between 30 and 50 gms per day of product. A 100gm sample of the <100nm nylon would cost several thousand dollars.
James Zeigler, a Research Associate with Dupont described studies where volunteers clad in various commercial protective nonwoven suits walked on an inclined treadmill at gradually increasing speed while heart rate, metabolic rate, skin and core body temperatures were monitored. The test was stopped when the core body temperature rose sharply (the onset of heat stress) and treadmill speed was recorded. This was assumed to be the highest work rate possible in the garment under test, i.e. the work rate where the garment is unable to dissipate the body heat being generated. Plots of Moisture Vapour Transmission Rates (MVTR) for the fabrics against the treadmill speed failed to show any correlation, but air permeability and treadmill speed were directly related.
Dr Zeigler concluded that the widely accepted relationship between “static” MVTR and thermal comfort could only be valid for a narrow range of fabric types with similar air-permeabilities. In the real world, body movement increases air-flow through the more permeable fabrics, overriding MVTR effects.
Condensation of moisture on the inner surface of the garment will also affect its performance in dynamic testing. Fabrics which can absorb condensation on the inside and evaporate it from the outside give better heat transfer than non-absorbent fabrics of similar construction.
Dr Pierre Vanhoorne of Bayer made a case for using polyacrylonitrile (PAN) rather than acrylic acid (AA) for producing superabsorbents.
- High purity glacial AA dimerises on storage so SAP plants need to be located on an AA production site.
- Acrylonitrile is in comparison a cheap commodity with supply exceeding demand and 12 major producers capable of shipping it around the world. 5.4 million tonnes are produced annually.
- Both AA and PAN are made from propene, but a new process will enable the PAN to be made from the cheaper propane.
- Bayer has sold their PAN fibre production to an Italian company, but has developed a new emulsion polymerisation process based on a polymeric surfactant, which is now being offered for licence.
There are two processes. In the first, PAN is hydrolysed with caustic soda in ethanol and neutralised with formic acid. In the second, newer “LIST” process, a high viscosity reactor allowed hydrolysis with aqueous NaOH. The resulting sodium polyacrylate has a soft “cauliflower” like structure unlike the glassy product from the AA process. This structure gives very high absorbency under load, extremely rapid liquid uptake and low rewet values compared with AA SAPs. (SAP properties were said to be the same from either process.)
- Mannequin test confirm an advantage in higher absorbency before leakage.
- Costs of the ethanol process from propene via PAN were 46c/lb c.f 47.5 c/lb via the AA monomer. However the new Bayer aqueous “List” process would reduce this to 39 c/lb.
- Less than 0.1ppm of monomer was detectable in the SAP, and acrylamide was undetectable (at 1 ppm sensitivity). There were 5% water extractables and no negatives in ecotoxicity testing.
- Bayer will not operate either process themselves for strategic reasons and offer the technology on yet2.com.
- The new process is operating on a 100lbs (batch?) scale.
Asked about respirable dust, Dr Vanhoorne said this has not yet been tested, but would be expected to be at lower levels than from the more brittle conventional SAPs. Consumer testing remained to be carried out.
Gerd Jonas, Managing Director of Stockhausen Inc introduced Degussa Firesorb™, an aqueous fire-fighting concentrate comprising 28% SAP, 23% oil (biodegradable) and 6% surfactant. When metered into water hosed onto a conflagration it:
- Adheres to vertical surfaces
- Excludes oxygen
- Absorbs heat
- Reduces run-off and collateral water damage
The concentrate is a water-in-oil emulsion which on dilution (0.42% SAP in the water emerging from the hose was quoted) inverts to an oil-in-water emulsion thereby releasing the SAP, allowing it to absorb and viscosify the water. This viscous fluid is non-Newtonian and under the shear forces in pumping and hosing presents little resistance. At higher concentrations the thickened water can be used to coat flammable materials in the vicinity of a fire: Firesorb™-protected plastic being shown to survive 45 minutes at 900 oC before ignition. Applications developed so far:
- Fire breaks in forest fire management
- Tyre fires
- Plastics (“solid petrol”) fires
Asked about the disposal of the treated water, Mr Jonas said it could be washed off easily and was safe in the municiple waste water stream. It had been sprayed onto firefighters to keep them cool while fighting forest fires in Spain. With regard to breakdown into monomers under heat Mr Jonas had no information, but commented that no “poisonous gases” were released. The main hazard appeared to be that it made floors very slippy.
Jared Austin, a Research Fellow with BBA Nonwovens provided a most comprehensive review routes to elasticity in nonwovens in the light of a belief that elasticity is a vital ingredient in the quest for ever more textile-like nonwovens.
Elastomers could be thermoplastic or non-thermoplastic, the latter being the traditional spandex or natural rubber products. The thermoplastic kind could be moisture sensitive (condensation polymers such as polyurethanes, polyetheresters and polyetheramides) or moisture insensitive (polyolefins and polystyrenes) Polyolefins were the cheapest of the thermoplastics (~$0.9/lb) but had worst stress-relaxation properties; styrenics ($1.20/lb) were better, with the polyetheresters ($3.50/lb) outperforming these and the polyurethanes ($3.00/lb). Very high molecular weights were needed to get the best stress-relaxation performance. (e.g. Kraton®: USP 4720415)
Because elastomers tended to be “sticky” and uncardable, they always had to be used in composite form for acceptable processing and comfort. Such composites had to be formed with the elastic in a pre-stretched state unless the non-elastic component could be engineered to allow stretch to occur. Pre-stretched laminates were described in USP 3,575,782; WO 99/17926; and USP 4,720,415. Examples of high-stretch non-elastics for laminating with elastics were parallel laid card-webs with high CD direction elongation – as used in BBA’s Sofspan® hydroentangled product and Ultramesh® calender bonded laminate.
Other products mentioned were:
- TANDEC’s process for drawing down and resetting a spunbond or meltblown to give a narrow fabric with very high CD elasticity,
- P&G’s “Ring-Rolling” process,
- Laminates with elastic nets (WO 00/44556),
- Breathable barriers based on microporous elastics,
- Elastic bicomponent fibres from Hills Inc., where the 10% non-elastic sheath buckled to give a fascinating creped skin on a 6 denier filament.
- Cross-linked thermoplastic elastomeric fibres being developed by a Dow/BBA JV.
Jim Cree (Marketing Manager) and Bill Deep (Global Product Manager) of Tredegar Film Products described how the vacuum-perforation process used to make apertured films could be adapted to produce laminates. Extruding the film-forming polymer onto a PP nonwoven prior to passing the combination, film side down, around the suction drum while the film was still plastic produced a two-layer product. A second layer of film could then be extruded onto the “male” side of the perforated film to give an even bulkier product without perforations. A wide variety of possible nonwovens coupled with a wide range of possible films and several different aperturing patterns led to an enormous array of possible end products. Those mentioned specifically were:
- Air-laid or spunlaced nonwovens laminated to film to give a 2-surface wiping effect. (e.g. Scouring and absorbing)
- Film laminated to 13 gsm spunbond to give a diaper backsheet.
- Elastic laminates for waistbands, side panels and medical bandages.
- Ostomy bag covers
- Automobile headliner by laminating film to chopped glass strand to PU foam.
In response to questions, USP 06303208 dated 10/16/01 was mentioned. The process would run in a 30 to 250 m/min range. It cost 20-30% less than glue lamination
Dr John McCulloch (Consultant) took us through the development of the fuel cell from its invention in 1839 by Sir William Grove (a Welshman), its use by NASA to provide water and energy in the 1960’s, to today’s specialist uses in over 250 systems in 15 countries.
Fuel-cell use is expected to grow both in special applications and as a result of the Exxon/General Motors collaboration to demonstrate their uses in automobiles. The way forward involves reducing their costs (cheaper, lighter materials), increasing their efficiency and developing cheaper sources of hydrogen. Opportunities for nonwovens appear to be related to the polymer electrolyte membrane cell currently favoured for automotive applications, and were listed as follows:
- Carbon and/or fluorine membranes
- Filters in ancilliary equipment
- Microporous carbon nonwovens as a gas-diffusion layer (Lydall)
- Nonwoven catalyst carriers (Technical Fibre Products)
Nancy Muller, Executive Director of the National Association for Continence presented the highlights from two nationwide surveys, one involving intercepting the general public in shopping malls, the other being telephone survey of NAFC members. Both studies confirmed findings from an earlier smaller study:
- The majority of citizens remain ignorant of bladder health issues
- 66% have never spoken to a doctor or nurse about bladder health.
- Half of those reporting symptoms of incontinence have never consulted a doctor.
- Women are less likely than men to seek help. 68% of women with a problem tolerate their symptoms as they gradually get worse, whereas half the men who suffered report the problem immediately.
- 25 million Americans are affected by incontinence now. The figure will be 30 million by 2020
- One-in-five suffer in their forties, and one-in-three suffer in their sixties.
In response to a question, Ms Muller said that skin health problems associated with incontinence were a greater issue for men than women.
Lisa Baker, a Senior Development Scientist with PGI presented the results of panel tests designed to show the benefits of their antimicrobial acquisition layer in controlling odours associated with adult incontinence. She characterised the odour problem:
- Dominated by ammonia arising from the breakdown of urea by urease secreted by bacteria.
- The human nose can detect 50ppm of ammonia.
- Faecal odours are a minor problem in comparison.
- Masking the ammonia smell is impossible,
- Absorbing it with zeolites works, but is expensive
- Eliminating it by killing the bacteria was the solution preferred by PGI.
The acquisition layer used an antimicrobial coupled with a pH buffer to control the pH on the acid side of the neutrality that the bacteria prefer.
For the panel tests, sections of adult pads with treated acquistion layers were inoculated with 100mls of synthetic urine seeded with various cultures of micro-organisms, and stored in closed containers with and without warming for up to 24 hours. Panelists were asked to smell the containers at intervals and rate the smell as better than or worse than a control which used an untreated acquisition layer.
The overall conclusion? More than 50% of the panellists thought the treated pads smelled better.
Ms Baker thought the acquisition layer, a card/thermal PP product could be used in diapers. The treatment chemistry was not revealed, but it was said to be non-leaching and EPA registered. The pH? 4.3, measured on an extract of the nonwoven. Could it be added to SAP’s or pulps where it ought to be even more effective? Yes.
Mike McCool, Partner, Eclipse FiberNet Corporation described the rotating autoclave (“Rotoclave”) designed to sterilise red-bag hospital waste before shredding and disposal. The Rotoclave has been shown to give an 8 log 10 kill of thermally stable bacterial spores. Mr McCool thought it would be possible to recover and reuse any nonwovens in the waste, but in reality they would be reduced to short fibres. One interesting feature of the process was that any plastics in the refuse tended to melt and ball-up, becoming easily separated in the discharge from the Rotoclave.
The system could, in theory, be used to treat the municpal solid waste stream, in which case 100 million tonnes of fluff pulp could be recovered from the paper component. Eclipse FiberNet was planning a 400-tonne/day system to investigate this.
John Tharpe, President of R&L Engineering reviewed early disposable product production methods and the barriers to be surmounted to reach high production rates. Being an ex-P&G’er, one of his examples was the Rely tampon process. This had reached production rates of 650 tampons/minute after solutions had been found to the following problems:
- Holes in the nonwoven from which the bag was made. (A laser scanning system was developed to detect holes and thin areas and this was linked to a product reject mechanism.)
- Glue deposits built up on the tube-forming mandrel while sealing the nonwoven into a tube. (Chilling the press-wheel caused condensation to form at the nip preventing the glue from sticking to the metal. Now ultrasonic bonding would be the solution.)
- In a design where the string would be invisible to the user until insertion, 100% detection of satisfactory attachment of the string to the bag was crucial. (The process was changed so that the string was used to transport finished tampons: no string, no product.)
In one case-study, replacing an old diaper machine with a new 30% higher-productivity machine at twice the cost increased the profit but adding a second old machine to double the output was the better, even more profitable option.
Joseph Neuwirth of Sonic Solutions Inc . has developed a rotary converter and horn system capable of sonic bonding at speeds up to 1000 ft/min where the conventional static horn runs into difficulties at above 500ft/min. The calender-like action of the new machine also makes it possible to bond the thick, bulky or high weight materials that were problematic on the conventional system.
The vibrating roller is currently made up to 2 inches wide and the system costs about twice that of the conventional type. This increased cost arises from the complexity and tighter tolerances of the rotating system. Applications on diaper and femcare lines are foreseen. In response to questions, Mr Neuwirth also felt the machine could replace high speed sewing machines and that when properly isolated, the bearings would not suffer from extra wear due to the vibrations.
Tony Butterworth (Consultant) argued the importance of fibre interaction at the micro-level in delivering strength, softness, dryness, absorbency, cleansing, filtering, and the appearance and touch of fabrics, be they woven or nonwoven. Taking wipes evolution as his main theme he reviewed the structures of Chicopee Keybak (60’s), Scott Paper High Loft (‘70’s), Kroyer and Honshu process airlaids and on through wet-wipes to today’s hydroentangled products including Swiffer®.
Concluding that the surface area presented by the fabric (typically 3-10 m 2 for every 1m 2 of materal) was crucially important, he reminded us of that curious combination of wet-lay and air-lay, the foam process. This was first operated by Wiggins Teape in the ‘60’s and improved by Ahlstrom who now lay 15mm fibres from micro-foam in a twin wire former, achieving levels of bulk and available surface area which Mr Butterworth thought would be valuable in today’s wipes.