Carlos Richer of Richer Investments said the diaper industry is in very bad shape. He argued that we are in the middle of a 7-11 year “purging cycle” which forces the closure of the inefficient, and drives the remaining smaller players to network with suppliers and retailers in order to better manage the proliferation of diaper types (SKU's). These purging cycles (aka global price wars) are triggered by supply chain problems, and this time it's the oil crisis and its effects on SAP price and availability. However by 2025 the following could be expected:
- Global diaper use would double as the number of users would increase from 1 in 5 today to 1 in 3. (Diaper use per baby would decline by 5% due to less frequent changing. The number of babies will increase only marginally)
- Compared with the 10 million babies in the USA , India (61 million) and China (42 million) had the largest population of 0-30 month-olds.
- While the % babies in the US population would increase slightly by 2025, the Indian and Chinese percentages would decrease slightly.
Using pre-segmented purchasing power parity (PPP) and knowing the minimum disposable income needed to trigger purchases of disposable absorbents, Dr Richer had also calculated the likely penetration of disposables by country. Full details were on his website www.richernet.com , where adjustments had been made to allow for unemployment levels (source of low-cost maids to wash diapers) and cultural resistance (Chinese reluctance to use diapers of any kind). The method suggested that India should now have 2% of changes on disposables, with China at 5.5%, Indonesia 9%, Brazil 30%, Mexico 59% and the USA 96%. There were other issues to consider when trying to assess growth potential. For instance, very uneven distribution meant that Brazil , Mexico and Russia would grow much more slowly than implied by the size of the unpenetrated market. In China , modern advertising could be expected to overcome the cultural resistance in the near future, leading to explosive growth of diaper sales. India would follow in 3-5 years time and will become the world's largest diaper consumer by 2025. North Africa also showed exceptional growth potential using this method.
Diaper design could be expected to evolve:
- To address the most important unmet-need: fewer changes/day.
- Desalination of urine by coverstock or ADL would increase the SAP's capacity.
- To dewater the SAP after disposal, microencapsulated salt would be added which would be released as the capsule dissolved in landfill.
- Microcapsules could be used in the coverstock to release buffers if the skin pH got too high.
- They would be compressed more highly to reduce volume in shipping and storage.
- Highly breathable nonwoven backsheets would be self-sealing, eliminating the need for film lamination.
- More elastic diapers would further reduce leakage (and reduce SKU's?)
- Air-laid preformed cores would be used.
- Pulp companies would move into diaper production in the emerging markets, but diaper companies would not integrate backwards to pulp products.
The adult incontinence market looked more attractive. The global population of over-70's would grow from 316 million today to 563 million by 2025 and with the expected increase in prosperity, the market for adult diapers would grow three or fourfold. China (62 million over 70's growing to 130 million) and India (32 million growing to 65 million) would lead this growth. There would be little growth in Europe which was already “old” in population terms.
In response to questions, cheaper to use two-piece diapers would lead the penetration of underdeveloped markets (J&J mentioned as active in this area). The SAP price/availability problem is temporary and will correct itself. China will sort out its intellectual property issues and start producing diapers. They are looking at exporting highly compressed diapers to Europe .
Bob Dennett, CMAI North America's Director of Polypropylene pointed out that since hurricanes Katrina and Rita, several refineries had shut down, feedstocks were limited, there was a hydrogen shortage and inventories were tight. The result: propylene from the refining industry would soon go above 50 c/lb for the first time. Quite apart from the short-term problems, demand for propylene, once a no-value by-product of ethylene production, was now exceeding the demand for ethylene and gasoline. 53% of the propylene produced in the USA in 2004 went to PP production. Alternative propylene technologies, such as propane dehydrogenation did not exist in the USA but were becoming a source in Europe . Metathesis i.e. ethylene + butylene à 2 propylene, was being developed mainly in Asia .
Global demand is expected to grow by 5% pa reaching 82 million tonnes by 2010. Of the additional 20 million tonnes needed by then, 2/3rds is expected to come from stretching existing capacity and the rest from new installations.
Propylene price is expected to peak in 2006 at about $900/tonne and then decline to ~$550/tonne as the new capacity comes on stream.
Polypropylene is now the largest selling polymer (24%) having taken the lead from PVC (19%). The polyethylenes follow with High Density (17%) Low Density (11%) and Linear Low Density (11%) Polyester and Polystyrene have 7% each. 2004 PP demand was 38.6 million tonnes and 16% of this went to fibers. The preferred pricing is in cents per cubic inch, which emphasises the advantage over the denser polyester. (PP=1.5 c/ci compared with PET 3c/ci.). The main expansion of PP production will be in the Middle East and North Africa, but this is unlikely to be economically exportable to the USA .
Polypropylene resin price is expected to peak in 2006 at around 70 c/lb and then decline to 40 c/lb by 2010. These prices are for general purpose high pressure injection moulding grade.
Ian Julian, also of CMAI gave the polyester section of the talk he presented to INTC – St Louis last month, adapted to take account of the Katrina and Rita effects. Almost 25% of the ethylene glycol capacity and over 12% of the paraxylene capacity in the USA was taken out by Katrina. The halt in oil production in the Gulf of Mexico compounded the matter. Chemical intermediate prices and hence polyester prices all ride on crude oil price, and while the hurricanes mean that the “highs” will be a little higher, the following “lows” will be even lower. He expects the increased imports into the USA which are now occurring to take advantage of the higher prices will overrun demand and lead to a polyester price collapse. However the shortages will lead to some substitution of polyester by other polymers and not all of this market loss will be regained as the prices fall.
Blake Kuster of Absorbent Technologies Inc reviewed the factors affecting the current SAP price/availability problems. The buyers market had gone and shortages, allocations and rising prices were the order of the day.
- 1.3 million tonnes of SAP capacity (nameplate) were in place, 38% in Asia, 35% in the USA and 27% in the EU.
- BASF is the leading producer with 24% share, followed by Degussa (21%), Nippon Shokubai (20%), Dow Chemical (11%) and San Dia (10%).
- Supply will grow by 8% in 2005 as two new Chinese plants come on stream, but this is still insufficient to meet demand.
- A further 5-6% pa demand growth is expected through 2008 but supply will grow by this level only in Asia and Europe . The US installations will be modernizations with no increase in output.
- SAP is made from acrylic acid, which in turn depends on propylene. Demand for glacial acrylic means that this is currently selling at prices higher than those available in the SAP market, which consumes about 25% of the 4 million tonnes of GAA.
- 70% of the new AA capacity is going into China who now make 7% of the global needs.
- With AA prices up 30% to $2400/tonne, there is no incentive to sell to SAP producers.
Why is AA becoming scarce and expensive? Because of higher demand than anticipated in the emerging markets, and higher usage in the increasingly popular water-based paints.
Propylene, a by-product of ethylene production, is the raw material for the polypropylene (60%) and the SAP (1%, via AA) needed in diapers. Here too demand is exceeding supply and propylene prices have doubled since 2002 (to $1000/tonne). Asked when the market would get back into balance Mr Kuster felt supplies would be tight through 2008 and further out it depends on how propylene production can be expanded. How should the nonwovens industry respond? Lock in your suppliers, multi-source and be prepared to change in the turbulent times ahead! Could more fluff be used? Yes but even that is in high demand especially in emerging markets. Could CMC's or crosslinked starches be used to make SAP's? Yes but they did not have the production capacity to fill the emerging gap. Concluding, Mr Kuster felt there could soon be a paradigm shift in absorbent product design.
Shuojia Dong of Groupe Lysac Inc. reported the development of starch-based superabsorbents specifically to blend with the increasingly expensive oil-based product on which most of the absorbent products industry now depends. Lysorb 220 was initially developed to blend with SAP to allow products to meet the Nordic Ecolabelling requirement of a minimum level of renewable materials and a maximum level of residual monomers and extractibles. Actyfill 20 , a glass-like starch gelatinized by extrusion, was then developed to blend easily with SAP at levels up to 20%, to reduce costs without affecting performance. This is now commercial and the next generation, Active Filler 2 offers greater cost savings by incorporating 26 to 60% of cheap naturally absorbent inorganic powders. Here some losses of performance (Free swell, centrifuge retention and absorbency under load) are observed at the 20% blend level with SAP. So, Active Filler 3 is under development, and this has the same composition as Active Filler 2 but uses a different extrusion process to boost absorbency and porosity. This has been tested in blends of up to 40% with SAP. Total acquisition times are slightly less than those of SAP either at normal loading or at 60% normal loading (with fluff pulp as the missing 40%). Total rewets were 0.2 gms for the 100% SAP, 5.9 gms for the 60% SAP loading, and 1.0 gms for the 60% SAP with 40% Active Filler 3 .
In response to questions:
- Lysac's capacity for Actyfill is about 35,000 tonnes/year
- Cost? “It is less expensive than the majority of SAP's”
- Could it be used above 40% blend? Maybe
- There are no IP issues with the process – Lysac have “right to practice”
- The materials are FDA approved.
- Their market share is increasing.
Mark Bolyen of Marketing Technology Services considered how diapers may be redesigned to use less of the increasingly expensive SAP. SAP prices bottomed out at about 65 c/lb in 2002 and since then had risen to over $1.10. Pulp prices, currently around $600/tonne, cycled between 500 and 1000 $/tonne. Using MTS's large database of diaper construction data Mr Bolyen has modeled the P&G Pampers and KC Huggies diapers to examine the effects of various core compositions on cost and performance. From the bewildering mass of results it appeared that using July 2005 prices P&G had scope to reduce SAP by 10% and increase pulp by 21% to yield a cost saving of about $1.10 per 1000 diapers without sacrificing much performance. K-C would save about $1.20 /1000 from the same change but would suffer more of a performance loss because their diaper already used less SAP than P&G's. Leakage performance could be maintained at even lower SAP levels if the elastication levels were increased to get better fit. However this would cost more. Reducing SAP content by localising it in the target area would be worthwhile.
Samantha Champ of BASF AG ( Germany ) described their work on Luquafleece, made by solution polymerization of a partially neutralized acrylic acid on the surface of the fibers of a nonwoven. A mixture of the monomer, cross linkers and initiator is sprayed onto a high-loft polyester nonwoven, polymerized and dried through an oven. The SAP appears as ~300 micron beads attached to the fibers of the fleece, one example having 200 gsm applied to each surface. The statement “50-500 gsm SAP can be applied to fleeces weighing more than 70 gsm” indicated 1 to 1 loadings of SAP on fiber ought to be possible. The shape of the beads on the fiber can be controlled by varying its wettability; hydrophilic finishes allowing the SAP to encapsulate the fibers in oblong blobs, while hydrophobics give spherical blobs. Silicone finishes give spherical blobs sitting on the surface and unattached to the fibers. The fleece with 400 gsm of SAP gives a saline free-swell of 18 g/g (7 liters per square metre) and centrifuge retention of 12 g/g (5 lsm). In addition to the currently commercial hygiene applications, the fact that it outperforms silica gel allows it to compete in climate control and several other applications:
- Packaging climate control.
- Food packing soaker mats.
- Horticultural watering mats - liners for hanging baskets.
- Chair seats and mattresses to achieve extra comfort.
- Filters to keep non-aqueous liquids dry.
Compared to silica gel, the Luquafleece releases the moisture faster when the humidity drops.
In response to questions, Ms Champ admitted that the saturated SAP is relatively easy to squeeze out of the fleece. The process of manufacture was specialized and she could not recommend in-situ polymerization on nonwovens production lines. The beads do have a core-shell structure. Luquafleece has been commercial in the EU for 2 years and the production capacity is fully utilised.
Torsten Brieger of Hermann Ultrasonics explained that adhesives and synthetic rubbers are based on isoprene, and the demand for isoprene is now unexpectedly high after a period of low prices and no investment. Isoprene comes from oil via the steam cracker as a by-product of ethylene manufacture, so the supply side is suffering also. Production actually declined in the first half of 2005 and shortages are expected to continue for some time. Allocation is inevitable, and new adhesives take a long time to qualify.
Sonic bonding allows adhesive-free assembly of hygiene products and the latest generation of machines with micro-gap control can produce consistently high-quality bonds at 500 metres/minute. It is now being developed to:
- Laminate the components of the cloth-like backsheets
- Attach the leg cuffs and the closure tapes
- Attach the elastic waist band and the frontal tape landing zone.
- Spot weld the acquisition distribution layer.
Micro-gap control, achieved by a stepper motor operating in 0.3 micron steps is the key to consistent operation at high speeds. It cannot compensate for variations in the number of layers to be bonded or the thickness of the nonwoven.
Christian Haas of Strahm Textile Systems AG ( Germany ) described the use of a 10-50 kV field alternating at 50-60 Hz to encourage polymer particles to distribute themselves uniformly through the thickness of a high-loft web. The non-conductive powder must be applied to the upper surface of the non-conductive web prior to entering the electric field, and the particles must be smaller than the pore size of the substrate. Particles do not move laterally, so they can be printed onto the surface in a pattern which will be preserved as it distributed vertically and then fixed in position through the bonding oven. As well as thermoplastic and thermoset powders for bonding, SAP powders, detergents and flame retardants have been rotary screen applied and used to make a variety of composites and nonwovens. Glass fiber mats and needlefelts of natural fibers have been bonded with up to 60% by weight of PP powder. Spun-laced nonwovens have been impregnated with detergents after drying.
Strahm will not sell the machinery but will sell the process for a licence fee. They have a pilot line which can be rented for prototyping.
Asked if the process would work with carbon powders, Mr Haas said it would, but would fail if carbon fibers were used. Operating speed would depend on the length of the electric field but it could be built to run sufficiently fast to work on an air-lay line. The powder can be shaken out before bonding and the impregnated web must be handled carefully. A mixture of powders may tend to separate in the field. There were no powder losses – nothing went straight through, and the running costs were low because negligible current was needed to create the voltage.
Phil Mango (Consultant) estimated the disposable wipes business to be worth $6billion at retail – 3x the 1997 value. The substrates were mainly air-laid thermal and/or latex bonded pulp/fiber mixtures or carded spunlaced fabrics.
- Globally spunlace was now in the lead with 150,000 tonnes while air laid had 100,000 tonnes of wipes sales.
- Total wipes worldwide amounted to 345,000 tonnes, 70% consumer and 30% industrial. Of the consumer wipes, 58% were Baby Care, 30% Household and 12% Personal Care.
- Air laid capacity (420,000 tonnes) was a little higher than spunlace (400,000 tonnes).
- Demand was about 75% of capacity in both cases, but the announced expansions in spunlace meant that the sort of overcapacity which plagued air-laid a few years ago could now begin to affect the spunlace sector.
- The air laid overexpansion was a blunder with both leading companies assuming they would get 100% of the growth, maybe linked to an over-reaction to the potential for preformed diaper cores.
- 21 of the installed air-laid production lines were M&J system, 22 were Danweb, 5 were Honshu and 2 were J&J.
- 23 of the installed air-lay lines could use both latex and thermal bonding, 15 were latex-only, 10 were thermal-only and 2 used hydroentanglement.
- Buckeye were the largest air-layer with 20% of the world's capacity, Concert (17%) and Georgia Pacific (14%) were 2 nd and 3 rd .
- Dupont and BBA were joint first in spunlacing with 14% of the world's capacity each. PGI had 13%, Orlandi 9%, Jacob Holm 8%, and Ahlstrom 7.7%. (The figure for Suominen – 10,000 tonnes- was well short of reality.)
- In 2006-2007 a further 60,000 tonnes of spunlace is due to come on stream including new lines at Ahlstrom, Orlandi and Spuntech in the USA .
- Air-laid should be the process of choice where the wipe had to be impregnated with solids, where true dispersibility was needed or where heavy basis weights were required.
In response to questions Mr Mango said airlace was a special version of spunlace rather than an air-laid nonwoven. Spunlace was best for super-softness. He thought big Chinese installations of either technology would impact the West either by displacing exports to China or by being exported while domestic demand caught up.
Fred Barlow (Consultant) offered some theoretical solutions to the SAP availability issue. The industrial revolution had commenced with the switch from wood to coal, had continued in the 20 th Cy with the switch from coal to oil and could be expected to switch back to biomass during this century. So how could biomass aid SAP supply?
- There was a biomass-to-acrylic acid route under development at the Pacific Northwest National Laboratory (funded by the US Department of Energy) which utilized the fermentation of glucose to lactic or 3 hydroxy propanoic acids or aldehydes which could then be converted to AA with acetic acid and calcium sulphate.
- Fluff pulp used to be modified by wet-cross linking or grafting to make a more absorbent pulp which was not sensitive to salt concentrations. A diaper with 100% wet cross linked pulp was said to be equivalent to a 60/40 pulp/SAP mixture for absorbency.
- Monocellulose acetate can cross-link to give a more absorbent pulp (USP 5142034). This is a natural product and might be biosynthesizable given genetic modification of plants.
Asked how soon these could be commercial, Mr Barlow said the bio-acrylic acid was in testing now, and the wet cross linked pulp could be mass produced in about 9 months.
Kent Lynde, Associate Director of P&G Global Household Care R&D described how P&G's unlikely but successful collaboration with their main Asian competitor Unicharm had helped create their latest billion-dollar business – Surface Care. Doubling P&G's business in 10 years means coming up with 500 new ideas each worth $100 million, and this could not be done simply by relying on the internal resources which work so well for incremental projects. So P&G's “Connect and Develop” program is creating a global inventor database and encouraging the use of external sources for big ideas. The target is to source 50% of the new technologies from outside P&G according to CEO A.G. Lafley, but without outsourcing R&D. After the successful launch of Swiffer Dry (1999), Swiffer Wet (2000) and Swiffer Wet Jet (2001) P&G turned to the Unicharm Wave Handy Wiper – the most successful disposable duster in Japan – for their next major surface-care product. Swiffer Dusters, based on an across-the-board collaboration with Unicharm, were launched in 2003 and became an immediate success in the USA gaining an 80% share and exceeding expectations by a factor of two. Global sales are now hundreds of millions of dollars and this new category is spawning new competitors daily. The nonwovens industry benefits from a major new outlet, in this case a thermal-bond laminated with tow fibers for maximum dust pick-up. The partnership with Unicharm allowed P&G to get a superior product to market in less than half the time it would have taken internally.
In response to questions:
- Swiffer Dusters use the same structure in every market.
- The tow is a mixture of polymers.
- They are not biodegradable and will have to be landfilled.
- P&G Japan, normally head-to-head with Unicharm, accept the arrangement. “We have firewalls”.
- The IP is owned by Unicharm. P&G operate under a licensing arrangement.
Keith Carnes of Wellman Inc. described fibers containing “naturally occurring optically responsive particles which recycle the energy released by the human body”. These solid fibers, looking remarkably like over-delustred polyester under the microscope, convert body heat into “wavelengths which are accessible to mitochondria, allowing them to increase the level of oxygen at the skin surface”. Wearers of textiles made from the fibre claim relief from pain, jet-lag, exhaustion and also experience enervation and increased physical strength. The garments also made you feel warmer and most importantly, increased transcutaneous oxygen levels (TCPO2).
Clinical trials on diabetics in Veterans Hospitals measured blood oxygen levels in hands and feet after wearing gloves and socks containing the fiber. This was a double-blind trial with ordinary polyester as the control. TCPO2 increased by 8-12% which according to Dr Lavery, the consultant used by Wellman, were compelling and significant and could be expected to increase circulation, reduce pain etc. A second clinical on healthy 18-50 year olds showed an average TCPO2 gain of 25% for the gloves (100% Holofiber) and 10% for the socks (50% Holofiber).
Commercial proving trials are now underway, with the TCPO2 benefits being confirmed in sports socks (13.5% TCPO2 increase), support socks (20% TCPO2 increase) and body pillows (a 9% TCPO2 increase if you snuggle up to it in bed). Thermography is showing that these garments increase body temperature by 6-8F even though they have no effect on heart rate. The development is a joint venture with Hologenix LLC, who was licensing new applications for the particles.
Dr Ullrich Münstermann of Fleissner GmbH estimated 2005 spunlacing capacity at 400,000 tonnes and the production of spunbonds (using INDA data) at 2 million tonnes. However the current production of spunlaced-spunbond was less than 5,000 tonnes. He further broke down the spunlacing market for 2004:
- 220-260,000 tonnes being carded staple
- 50-55,000 tonnes being carded staple with pulp from tissue
- 90-130,000 tonnes being carded staple with air-laid pulp
- 21-26,000 tonnes being wetlaid
- The estimated total spunlace from this slide was 435,000 tonnes
In 2003 spunlaced accounted for only 30% of the North American wipes market (c.f. 66% in Europe), but this was now increasing sharply due to the P&G decision to replace air-laid with spunlace.
Fleissner's Aquajet spunlacing system had evolved sufficiently for them to offer two possibilities involving spunbond: to soften and bulk a thermally bonded spunbond to make it more textile-like (“Water-jet texturizing”), and to fully-bond a spunbond-pulp-spunbond laminate for wipes, both at speeds up to 600 m/min and widths up to 5.4 meters.
For the wipes option, they proposed 48 gsm of air-laid pulp bonded between two 8 gsm polypropylene webs and claimed this would halve the raw material costs (compared with a 70/30 viscose/polyester) to €0.762, assuming viscose at €1.7, polyester at €1.1, PP Chips at €0.8 and pulp at €0.75, all on a per kilo basis. The spunbond – airlaid – spunlace line would produce 35,000 tonnes/year and having lower fixed costs would allow wipes substrate to be made at 65% of the current costs of the viscose/polyester blend on a 12,000 tpy 2-card line. The proposed line would use a single bonding zone working on the three-layers.
Asked how much pulp would be washed through the 8gsm PP bottom layer in the bonding process, Mr Munstermann thought 10-15%, adding this would be easily dealt with in the water recycling system.
Ron Jones of Air Products Polymers LP reviewed the methods used to assess the dispersibility of nonwovens, including the P&G/WERF method, and mentioned the soon-to-emerge INDA/EDANA method. APP had looked at the NSF beaker snag test, the tube dispersion test and the orbital shaker method and decided to develop their own method – The Hobar Test. In this test a real toilet was used, but unlike the methods at WERF, NSF or Herriott-Watt University (UK) the, outlet pipe was short and dumped the contents of the flush onto a screen. If the sample has enough integrity to be removed from the screen and reflushed, this is done, up to five times. If it survives 5 flushes and remains handleable it is deemed not flushable. Toilet papers pass the test.
6 flushable commercial wipes were evaluated on these four methods, along with one non-flushable commercial wipe and two experimental samples made by APP. The APP Hobar test passed the two samples made by APP and failed the rest. Snag break-up only passed one of the APP samples while the shake-flask test and the tube-dispersion test both passed both APP's and a 48 gsm commercial HE rayon/pulp 7”x10” household wipe. The bonding methods used were not revealed other than the best of the APP samples being PVOH/boric acid the other “using sodium sulphate to develop lotionized wet strength”. APP argued that these binder systems would be fine for kitchen/bathroom applications if not for personal care.
Asked about the salt concentrations used in their experimental samples, Mr Jones said 4.5% boric acid in one and 7.5% sodium sulphate in the other.
Richard Annis of Ahlstrom Fiber Composites Division pointed out that the flushing of wipes was having an adverse effect on municipal wastewater treatment, attracting negative press in both Europe and the USA and legislation was now emerging to ban their disposal in toilets. This could even rule out wipes designed to be flushable.
Criteria for flushablility, according to EDANA/INDA will be:
- Does not block the pipe work.
- Has no effect on either municipal or septic tank treatment systems.
- Has no effect on the environment – visibly or chemically.
Products which are flushable by size only will meet 1. but may cause problems with 2. and 3. The target is toilet-paper levels of flushability with wet-wipe levels of wet strength, and this is not achievable using conventional bonding systems. Water soluble binders have to be used and these must be strengthened by the lotion and weakened when diluted with the flush water. Examples are PVOH binders with borates in the lotion, Polyacrylic/methacrylic binders with calcium in the lotion and newer polymers (unspecified) with high sodium concentrations in the lotion. Of these the PVOH's and polyacrylics have not found wide acceptance due to their potential to irritate sensitive skin, and/or their failure in hard water areas, and/or the added complexity of lotion formulation. The newer sodium-triggered binders are still under development but look better.
Ahlstrom's Dispersible Hydraspun is a hydroentangled wet-laid blend of pulp and short viscose or lyocell. Unlike fibers of cardable length these disentangle relatively easily when wet and provide a firmer foundation for flushability claims. In the Tube Dispersion Test, Hydraspun 784 breaks up in 18 turns while an air-laid “flushable by size” moist toilet tissue is still intact after 50 turns. Independent testing at Courtray Consulting, Brunel University and the Stevens Institute confirm both the dispersibility and the biodegradability of the material,
Jörg Dahringer of Trevira GmbH, Germany reminded us of the advantages of a PET/PE bico fibre over the more commonly used PP/PE:
- At the same decitex, the PET product has a lower diameter and hence higher bonding efficiency.
- The melting point differential between PET and PE is 120C yielding a less critical bonding process.
- The PET core is stronger than the PP core.
Trials with variations on Trevira Type 255 - a 1.7 dtex/6mm 50/50 PET/PE bico - in blends with woodpulp yielded the following conclusions:
- The optimum decitex (for highest nonwoven strength) was 1.7
- Strengths increased as staple length increased from 3-12mm, with a hint of a plateau between 6 and 9mm.
- Removal of the coupling agent from 1.7/6mm T255 reduces the nonwoven strength from 33 to 8 N/5cm. (The coupling agent is added to the PE sheath to improve bonding to cellulose.)
- The optimum core-sheath ratio was 50/50. (60/40 and 35/65 giving significantly weaker nonwovens)
- If the core was off-center in the sheath, the fiber and nonwoven could be further bulked by heating to 120C. This allowed latent spiral crimp to modify the mechanical saw-tooth crimp added for processability.
James Westphal of Troika Technologies Inc reviewed the history of air-laying from the original Kroyer process to the recently announced Celli former. Because all of these systems use a screen through which the fibers have to pass, their productivity and long-fibre handling capabilities are limited. He suggested the way forward was exemplified by the screenless former invented by Carsten Andersen of Formfiber Denmark and described in US 2005/0098910. This system is said to be capable of:
- 700kgs/hour/metre per forming head,
- Handling dust up to 50mm staple fibers
- Operating with “Zero Waste”
- Manufacturing 50 – 5000 gsm webs.
The equipment is intended for making heavyweight waddings and insulation panels out of coarse fibers such as hemp, flax and reclaimed wool and as such will be appropriate for a heavier range of products than today's other air-laying processes. Nevertheless, directionally, screenless systems appear to offer development potential for lighter, longer-fibered products.
Rob Cesena of 3M promoted their range of fasteners. Of interest to the hygiene products producers were:
- The extrusion bonded nonwoven loop (“EBL”) which looked like a parallel-laid web, gear crimped into waves and locked into this state by extruding a polymer film onto the back. Said to be low price with premium look and feel.
- Knitted loops, looking like air or water - jet texturized lightweight knits (plain or velour) made of continuous filament yarns and bonded to a printed film backing.
- Micro-replicated hooks formed by film extrusion onto a mold which creates vertical “posts” on one surface. The tips of these posts are melted to create a mushroom shape which can attached to looped fibres.
- Profile-extruded hooks appear to cast film onto a mold which forms continuous ridges with a mushroom-shaped section. These ridges are then cross-cut prior to MD stretching the film to create the individual hooks.
Asked if they had any hook systems which would work with plain spunbond, Mr Cesena said they did not. For adult hygiene products the principles were the same as for baby products only the hooks and loops had to made bigger.
Detlef Frey, the R&D Manager of Reicofil, said Reifenhäuser has split into two and Reicofil is the new name for the nonwoven division, the other being packaging. Their recent work to optimise the melt-blowing process involves:
- Allowing adjustment of the inclination of the forming conveyor to optimize the pore structure and laydown of the web.
- Recognizing that losses of barrier properties (hydrohead) are due mainly to small holes in the web, these being mainly associated with “shot” (blobs of polymer formed when a filament breaks close to the jet).
- Working to minimize shot by optimizing the machine set up, thereby increasing hydrohead from 600 to 800 mms water. Part of the change involves moving from 25 to 35 holes per inch without increasing throughput.
- Optimizing the resin properties to minimize shot thereby increasing the hydrohead from 800 to 1000 mms water.
The “new technology” arising from this optimization allows the production of finer fibers than hitherto possible. 40 gsm webs now allow filtration of 95% of 0.392 micron particles at a pressure drop of 250 Pa according to DIN EN 1822-1.
Asked what percentage of fibers in this improved web would be below a micron, Dr Frey admitted that they could not measure this. They preferred to look at bulk properties such as hydrohead. What resin variables other than MFI could be changed? They had focused on reducing the coefficient of variation of MFI.
Rory Wolf, VP Business Development for Enercon Industries described how they had combined their plasma treatment (APT) with photografting to achieve permanent improvements in the wettability of polypropylene. The roll-to-roll process now works at commercial speeds and the dielectric barrier discharge “glow” is relatively cool at 300C: the plasma power density being insufficient to damage a nonwoven.
An 18gsm spunbond was passed through the APT station running at 2.2 kW output power and using 6.4 l/min of helium and 1.6 l/min oxygen. 1 gsm of water based photoinitiator was printed on, IR-dried and UV-cured. Surface tension increased from 34 to 54 dynes/cm through APT and stayed at this level through photografting. Neither the odor nor the color of the spunbond are affected by the treatment. The main objective appears to be to improve the printability of the nonwoven, and much enhanced peel adhesion was claimed (7 fold increase on APT alone and 8-fold after APT + photografting.)
In response to questions:
- Visual graphics quality is much improved by the treatment.
- Water-based flexo-inks can be used
- Energy consumption in APT is 1/3 rd that of corona treatment.
- Gas losses on the 16” line cost $2-3 per hour.
- Process speed? not revealed but the line is designed for 1400 ft/min.
- There are no health/safety issues. Ozone levels in the gas remain below 15 ppm.
- The maximum surface tension achieved on PP is 72 dynes/cm – before photografting but presumably not permanent.
John Wolhar of FiberVisions Inc. first addressed the supply problems. World polypropylene capacity is increasing and some of that capacity will use new propylene technology which is less dependent on oil. Prices will return to normal, polyester will always be more expensive than PP, and rayon will continue to be volatile but overall, despite its lesser dependence on oil, would maintain its price relationship to cotton and the main synthetics.
FiberVisions “Hy-Wettable PP” can be hydroentangled into a durably hydrophilic nonwoven with about 80% of the total capacity of a rayon nonwoven in a detergent-free test. In wet-wipe storage testing the top layer wipe of a 70/30 HWPP/PET stack is wetter than the control 70/30 rayon/PET stack after 3 weeks, but the bottom layer wipe is, if anything, slightly wetter also. The wipes are stronger and bulkier when the rayon is replaced by HWPP.
Major increases in bulk can be obtained by layering a new “Hy-Shrink PP” with regular webs prior to thermal bonding. The thickness of the nonwoven doubles from 1mm to 2mm in through-air bonding.
- Finer fibers are available for increased strength, softness and cover.
- Thermal bonded blends of regular or Hy-Shrink PP with HY- Wettable PP would allow the production of low-cost wipes with high bulk, softness and recyclability.
- Fine denier polyethylene fibers are now commercial and give outstanding softness.
- Polyolefin binder fibers can be used to bond natural fibers into strong, lightweight structural composites.
In response to questions, the Hy-Wettable PP does not imbibe water, it just has a durable surfactant at the surface. This additive adds 3-5% to the fiber cost. Were there any new ways to improve the efficiency of bonding bico fiber to pulp in air-laid? None that Mr Wolhar was aware of.
Pricie Hanna, VP of John Starr Inc, previewed a study done with Helena Engqvist Consulting on the likely impact of advances in drugs on the market for hygiene products. The prevalence of incontinence is rising due to population ageing and the increasing prevalence of prostate surgery, obesity and diabetes. By 2050, 20% of the world's population will be over 60, including 35% of Europe and 26% of the USA . The key pharmaceutical companies developing drugs to treat incontinence include Pfizer, J&J, GlaxoSmithKline, Ely Lilly, Novartis, Yamanouchi and P&G. Several new drugs for over-active bladder were introduced in 2004 and 2005 and many more are in the pipeline. Stress incontinence is proving harder to treat, with one new drug using dulozetine approved in Europe but not in the USA . Also in 2005, collaborations between P&G and Novartis, Yamanouchi and GlaxoSmithKline and Takeda and Toray were announced, all targeting faster introductions of both prescription and OTC products to treat incontinence. The bottom line? Drugs will reduce the market for absorbent products but the impact will not be felt for about 5 years when OTC sales will commence. Ms Hanna was unaware of any documentation on the size of the obesity effect, and with regard to the impact of drugs on the feminine hygiene market, that would be the subject of another study.
Gerri Potash of Nerac Inc suggested using the following sources to obtain information about competitors:
- Web-logs or Blogs: contain much useful comment on product performance but with 18.5 million in existence even keyword searches fail. Here Intelliseeks Blogpulse can help.
- Competitors web-sites can be monitored automatically for changes.
- Contacting their customer service department to obtain newsletters and literature adds perspective.
- Corporate authors' contributions to peer-reviewed technical literature and trade journals could be monitored.
- Patent and trademark databases can provide early indications of new product development.
- Market studies and reports are often abstracted for trade magazines. Sometimes they can be purchased in sections to reduce cost.
Beth Hanson of Marketing Technology Services reviewed the anatomy of diaper dermatitis and ways of preventing it. While it's incidence has fallen dramatically as disposable diapers became drier, she felt further improvements are still possible:
- More air is needed in diapers – they should be made more breathable.
- Barrier protection for the skin could be incorporated in baby wipes or coverstocks.
- Baby wipes should use lower pH lotions.
- Users of diapers should be provided with more dermatitis-prevention information on packs and websites.
Mark Snider of Nordson Corporation provided a basic introduction to bicomponency leading to a description of the features and benefits of their NanoPhase bicomponent meltblown technology. This bico system allows normal throughputs to be used while obtaining submicron fibres from segment-pie extrusion. Asked how the segments were separated after formation, Mr Snider said they fell apart in the turbulent air, the polymers and additives having been chosen to prevent the segments from adhering together. The meltblown webs can be calendered to give microporous films.
Frederic Noelle of Rieter Perfojet described trials with wipes substrates where PLA had replaced the polyester. Old data from Courtaulds (circa 1990) showed how lyocell, viscose and cotton degraded in a sewage farm and old data from Cargill-Dow showed how PLA degraded after pre-hydrolysis. Then wipes disappeared in 60 days. Asked if there were any issues processing PLA, shrinkage was mentioned.
Jim Hanson of MTS Inc is testing a wide range of hard surface cleaning products and will soon be offering a report for sale. This paper provided a glimpse of the methodology and results. The best was “Swiffer” (dry) and “Mr Clean” (wet).
Jim Robinson of PCMC re-read the paper given at INTC – St Louis by co-author Kevin Marrick. In response to questions he said the big growth area now under development was the printing of diaper topsheet. They were collaborating with a speciality ink producer. Expandable inks used 3-4 micron particles in suspension. Printing on spunbond could be done reliably providing the basis weight was not too low.
Bob Makolin (Consultant) marvelled at the way hydrogen bonding increased the strength of a paper as it dried and wondered if the method could be used to increase the strength of air-laid nonwovens. He concluded that the high levels of moisture, heat and pressure needed to form hydrogen bonds are not usually present in air-laid processes and capital availability will dictate the speed with which the technology becomes fully developed.
Technical Absorbents Ltd (UK) have several interested buyers, one being prepared to put in the necessary expansion and longer-range strategy. The superabsorbent fiber plant has been stretched to 3200 tonnes/year and is still oversold, mainly into food packing soaker pads. Expansion to 10,000 tonnes/year would be possible on-site with the right investment. The neighboring acrylic fibre plant is closing and a buyer is interested in the tow production (carbon fiber precursor).
Natureworks LLC is making progress with cost reduction and can now match polyester chip prices with the lower melting point PLA. They seem to be disenchanted with textiles having learned the hard way that fibers with melting points like PP are not good in durable garments.
Tencel ( Mobile ) is still at half rate following Katrina.
BBA's Materials Division – the nonwoven production division - is likely to be demerged or sold off to allow more focus on their main aerospace business. Their Chinese air-lay operation is already up for sale.