EDANA – International Nonwovens Symposium - Stockholm 5th and 6th May 2009

Introduction

The economic climate and the fact that several companies were restricting travel meant that this meeting was less well attended than in previous years.  Nevertheless EDANA reported a total of 200 delegates.

Hydroentangled Spunlaid Nonwovens

Achim Grefenstein, Director of Corporate R&D for RKW (Germany) described their experiences with the world's first spunbond system with on-line hydroentanglement.  The 2-drum HE stage with 2 injectors per drum comes before a thermal bonding calender and can be used as well as or instead of the thermal system.  When HE is used instead of thermal, a belt,  which can also use an injector, transfers the fabric over the calender.  The drums have microperforated metal sheaths rather than wire-mesh to allow greater patterning and aperturing flexibility.  The benefits of HE over thermal bonding of a PP spunlaid web were listed as follows:

·        Higher strengths and work-products (tenacity x elongation) were possible

·        Bonded fabrics were twice as thick as calendered fabrics and hence more absorbent.

·        Drape and softness was much improved

·        Permeability (air and liquid) was higher.

Compared with hydroentangling card webs of PP:

·        The finished product was lint free

·        Abrasion resistance was higher.

·        Process water filtration requirements were minimal.

Basis weights of 20 to 120 gsm could be produced with HE compared with 10-120gsm using thermal bonding.  The new Hyjet® product has been commercialised in panty-liners, personal and technical wiping cloths, construction fabrics and coating bases.  At present the line is mainly used in thermal mode, but the production of HE-only is increasing.

Asked about line speed, Mr Grefenstein said the HE stage was not a limitation, and fabrics could be made at normal spunlaying speeds.  It was thus 30% faster  than card/HE systems which according to Mr Grefelstein could achieve 300 m/min.  With regard to price, the HE versions would be more costly than thermal versions due to the higher energy needs.  For wipes, the absorbency of hydrophilically treated HE PP fabrics was much higher than similar thermal bonded fabrics, but was still less than carded viscose/PP blends.  With regard to line efficiency (uptime), this has yet to be established because the HE production runs are short.  One questioner asked if saturated hot steam had been used as a bonding fluid.  Not yet was the answer.

Nonwovens from Natural Fibres

Rudiger Weinhardt, Director of Sales and Marketing for Fleissner GmbH (Germany) talked mainly about the production of HE bonded cotton make-up removal pads, including the latest developments with steam entanglement. Cotton pad hydroentanglement typically runs at low speed (~20m/min) on heavy webs and achieves about a tonne per hour of throughput per line.  However the most recent machine sales have been in relatively low capacity lines (~600kg/hr) in emerging markets.  2 new lines started in Russia in 2008-9, and several producers of bleached cotton textiles are interested in entering the nonwoven market by using HE to bond webs from existing narrow roller-card lines.

The resulting downsizing of HE bonding systems is allowing Fleissner to build “Mini-Jet” systems that fit in shipping containers and need minimal assembly at the customers site, and is also encouraging them to develop narrow roller cards for improved web-forming.  These Mini-Jet lines can be used as pilot lines, one being available for hire at Louisiana StateUniversity.  They are available in half and one metre widths, operate at up to 55 m/min using water pressures of up to 400 bar

 Old cotton cards typically produce webs of around 15 gsm and many are required in line to build up a cotton-pad.  Fleissner's new Trutzschler TC-07H card with “Shoving Unit” gives 100 gsm randomised card-web, 4 being required for cotton pad production.  Differing grades of cotton allow three-layer pads to be produced using fine “comber noils” in the outer layers and coarse “Scheletons” in the centre.

Wet-wipe production from 100% cotton is still a niche business, but growing.  200 m/min line speeds can now be achieved with bleached cotton (i.e. about 2/3rds of that with viscose/PP).  A new line in India plus 2 in Eastern Europe could add 10,000 tonnes of 100% bleached cotton wet-wipes to the market during 2010.  For wet-wipes, Fleissner recommend their Erko EWK 413 random card feeding an Aquajet or Leanjet HE unit.

Cotton-pads made on an experimental steam-jet bonding system using steam up to 20 bar and 250^oC show improved loft and softness.  The process is cheap and simple because no drying or water filtration is needed.  Hydroentangled flax fabrics are also under development.

Asked if cotton pads could be made with fluff pulp as a middle layer, Mr Weinhardt said they could but this was not yet commercial.  Were Fleissner using the Mitsubishi Steam Jet technology?  No, they had licenced the STFI patents.  Steam could be used to bond superabsorbent fibre webs without need for drying, and could also thermally bond 100% polyester. Cotton pads excepted, steam bonding would not be able to replace water bonding, but could give an interesting range of new products.  One “questioner” observed that the consumers were wrong to think that cotton was a green environmentally friendly fibre.

Biocelsol revisited

Pertii Nousiainen, Professor of Textile Materials at Tampere University of Technology, (Finland) reported on progress with the EU funded project targeting biotechnological processes for the manufacture of cellulosic products.  The principle is to improve the aqueous alkali solubility of cellulose by enzymatically degrading it.  Work so far has established that the degradation of a commercial dissolving pulp with ethyl gluconase enzyme at pH5 for 5 hours gives a cellulose that will dissolve well in 7.8% NaOH containing 0.84% zinc oxide (i.e. sodium zincate) at -5^oC to give spinnable solutions containing up to 6% cellulose.  This dope can be spun into a dilute sulphuric acid bath to give fibres with a circular cross-section, a crystallinity of about 40%, tenacities of about 1.8 cN/tex, elongations of about 16% and water imbibitions of about 170%.  This high absorbency arises from the porous nature of the fibre; its specific surface area, at 1200m²/gm, being twice that of viscose fibre.

 Films have been made by casting the dope on glass sheets, and these were similar to cellophane with tenacities in excess of 100MPa and elongations of 20-30%.  The Biocelsol dope could also be used to bond papers for sausage casings, but here a version without the zinc oxide was required and this meant lower cellulose concentration and a reduced level of impregnation.

Cellulose beads from Biocelsol dopes were smaller and more variable in size than those from viscose, whether produced from a rotating atomizer or an electro-sprayer. 

Nano-cellulose particles can be prepared by coagulating the dope in acid or salt baths followed by ultra-sonification or dialysis.  Ultra-sonification produced 200 nm particles, and dialysis produced a smaller number of 300nm particles.  The size also varied with the salt bath used, common salt producing the smallest particles and zinc chloride the largest (10 microns).

100% Biocelsol sponges were not possible, but when the dope was reinforced with cotton fibres some promising results were obtained.

Asked if the fibres fibrillated like Tencel, Prof. Nousiainen said they had yet to test for fibrillation.  Did the high absorbency make hydroentanglement difficult?  Again, no data yet.  Was -5^oC processing expensive?  Probably, but this was an optimum temperature:  higher temperatures could also be used.  A viscose producer pointed out that the process would be more energy intensive than viscose.  Prof. Nousiainen said it did need a little more energy, but felt this could be reduced.  They had to work on increasing the cellulose concentration in the dope, reducing the alkalinity, increasing the fibre strength and developing a pilot plant to work on a meaningful scale.

Privately Prof Nousiainen said there was a pilot process (dope making) operating in China, and the Yangtze(?) company were hoping to scale it up in the near future.

Natural Antimicrobials

Michaela Messina, a QA manager with Nuova Pansac (Italy) suggested propolis (a sealant used by bees in hive construction), as an antimicrobial for use in hygienic products. Propolis comprises 50% resin, 30% beeswax, 10%  oil and 10% flavanoids – the active ingredient.  NP micronise the propolis and make a varnish out of it.  This can be used to coat the inside of breathable backsheets used by hygienic absorbents, and if zeolite is added to the varnish a combination of antimicrobial and odour control features are obtained.  Testing for efficacy against silver and triclosan controls using Candida albicans, Pseudomonas aeruginosa and E. coli showed the Propolis to be roughly equivalent.  Odour reduction testing showed a 42% benefit compared with untreated controls. 

 Questions regarding the concentration of flavanoids in the varnish, and the application rate could not be answered at this stage, but skin contact testing was satisfactory.  Asked for details of the odour reduction test, Ms Messina said it was a 5 person panel test at Milan University, but the smellers were experts in their field.  Breathability of the backsheets was unaffected by the varnish (!)  NP had not notified the Biocidal Products Directive and appeared to think this was not necessary.  Were they aware of babies suffering allergies to honey?  Yes but this was by ingestion.  There was no information on skin contact, and in any case they used highly purified flavanoids.

How to make PP Hydrophilic

Sandra Husman, an R&D Scientist with Schill and Seilacher (Germany) reviewed the chemical and physical ways of increasing the surface energy of polypropylene to render it durably hydrophilic.

Chemical

·        adding hydrophilic comonomers

·        grafting on e.g. acrylic acid (photoinitiated)

·        grafting with plasma treatment in oxygen.

Physical

·        Surface active agents, reactive and non-reactive

·        Polymer additives

Most suffer from a decline in hydrophilicity over time, some have toxicological side-effects and the simpler surfactants tend to be removed by washing. S&S have therefore worked on reducing the wash-off of surfactants, using the standard test for “extractable surfactants” as a guide.

 urfactants form organised sub-structures called micelles and these can form cubic hexagonal and lamellar structures on drying.  Sometimes they form a gel phase which cannot be rinsed off, and this effect can be used to impart more durable hydrophilicity to PP nonwovens. True wash fastness cannot be obtained but the nonwovens can pass the strikethrough and wetback test over far more liquid insults.  Unfortunately,  the tendency to form gel phases also makes the most durable finishes based on  cationics or anionics hard to process.  S&S now suggest a tailor-made non-ionic based on optimising the hydrophilic-lipophilic balance to achieve better bonding to the PP.  The resulting VP3HA 629/5 offers well-balanced hydrophilicity – strikethrough below 3 seconds and wetback below 0.2g -  with minimum of finish rinse-off.

 In response to questions, Ms Husman said the finish works best on SSS nonwovens because the amorphous nature of the meltblown in SMS allows more finish migration.  Ageing tests suggest an increase of strikethough time of 0.5 seconds in 2.5 years.  The finish would not be durable to hydroentanglement, but it should be good in carding according to lubricity and antistat measurements.

REACh for Nonwovens

Barry Podd, Global Regulatory Affairs Manager, Kimberly Clark (UK) defined the acronym as Registration, Evaluation, Authorisation and Restriction of Chemicals to remind us that Restriction, arguably the most important word, is usually omitted.  The original objectives were:

·        Protection of health and the environment

·        Maintaining the competitiveness of EU chemical production

·        Prevention of fragmentation of the internal market

·        Increased transparency

·        Integration with international efforts

·        Promotion of non-animal testing

·        Conform with international obligations under WTO

The regulations came into force on June 1^st 2007 and the programme of registration will be phased until 2018.  A list of pre-registered substances (December 2008 to March 2009) and a candidate list of Substances of Very High Concern has now been published.  Substances are defined within REACh as chemical elements and their compounds plus any impurities;Preparations are mixtures of substances; an Article is an object with a special design which determines its function more than does its chemistry.  Articles are divided into those releasing chemicals intentionally, those releasing them unintentionally, and Containers with Preparation.  Nonwoven wipes would be Articles with no intended release, fragranced wipes would be Articles with intended release, and baby-wipes or moist toilet tissue would be Containers with Preparation.  Any released chemicals must be both pre-registered and registered under the REACh regulations.

Only 15 SHVCs are listed so far and these are CMRs, PBTs, vPvBs, endocrine disruptors etc.  Other toxic, irritant or corrosive materials are likely to be added, especially the 267 materials on the SIN list (Substitute it Now!) and the 306 materials on the Trade Union list, 191 of which have occupational health issues.  If the SHVC is present at above the 0.1% level in an article the article would be restricted, but discussion now centres on whether the 0.1% limit should be applied to the whole article or any of its components.  With 6 EC members in favour of calculations based on the components, and the other 21 favouring the whole article, a  resolution is nowhere in sight.

Summarising, Mr Podd said the publication of this candidate list of SVHCs has brought some new “communication responsibilities” for the manufacturers of nonwovens.  Asked about the SIN list Mr Podd thought all the substances on the old Annex 1 list would be transferred.  K-C are dealing with questions from professional users regarding the Candidate list but have no questions on the SIN list yet.  There are no questions from consumers: “Reach is too complicated: consumers don't know what to do with it”.  Asked about REACh and its relation to the EU Biocidal Products Directive, Mr Podd said any products already notified under the BPD are exempt from REACh registration, but only if they are used as biocides.  So, ethanol used as a biocide is exempt, but as a general chemical it must be registered under REACh.  What about nano-materials? Nanotubes have been registered by 2 companies, but the situation for other nano-forms is unclear, but for the fact that they can't be used in contact with food.  “Watch this space!”

Adhesives for Nonwovens and REACh

Hermann Onusseit, Technical Director of Henkel (Germany) considered Exposure Scenarios under REACh for the use of adhesives in the production of nonwovens.  Under REACh, producers of adhesives and hygienic disposables are both “downstream users” of substances.  As such they have roles and obligations under REACh whereas final consumers are not downstream users and have no obligations other than to read the instructions for use and comply with them. 

 These roles and obligations will involve producers in much additional work in communicating with suppliers and customers with respect to detailed safety information and with respect to checking that the substances used comply with the regulations.  For the moment, all formulators must ensure that the chemicals they use in their preparations are pre-registered by the supplier or importer.  If not they must be removed from the market at the end of the registration period for their tonnage band. In future, all pre-registered substances must be fully registered before 2018 at the latest.  Adhesives producers must then make sure that any use of a substance – as defined by “Identified uses, Exposure Scenarios and Risk Management Measures” in either their own plant or in their customers plants, is covered by a Registration Dossier.

 Considering a hot-melt diaper elastic attachment adhesive, itsUse would be under SU 3 “Industrials”, its Process would be under PROC 8 for solids handling and PROC 10 covering low energy spreading such as  roller application or brushing. Environmental Release would be under ERC5 covering temperatures above 70C, and Risk Management Measures would involve wearing gloves and goggles.

 Could EDANA help with this complex area?  Pierre Wiertzcommented that they would be forming an Exposure Scenario Task Force but would only be considering a handful of different scenarios.  Hygiene products were currently considered under Paper Products and EDANA were lobbying for them to be under Plastics or in a new Nonwoven category.   

Hygienic Nonwovens – Just another process industry?

Jonathan Bourget, VP and General Manager (EMEA) for PGI Nonwovens (Switzerland) came into nonwovens from the sheet metal industry a year ago and listed the main characteristics of that industry:

·        A few large customers keep prices down

·        Heavy overcapacity

·        Returns on investments diminishing

·        Competition from start-ups in other regions

·        Raw materials are a major cost element and prices are volatile

·        Innovation for new products has declined in favour of innovation to reduce costs.

In the 1970's there were 12 aluminium producers who had had to consolidate to today's “big-three”.  Cost savings came from ever bigger investment in larger plants, increasing the rate of equipment obsolescence. The industry was selling at below replacement cost and, in effect, liquidating itself.

 Mr Bourget thought the parallels with spunbond nonwovens production to be self-evident.  While nonwoven growth rates are healthy, prices are low because supply exceeds demand, and bigger investments are constantly needed to achieve economy of scale.  The ability to innovate is restricted, polymer and energy prices are high and volatile, and the hygiene industry demands high volumes of identical fabrics.  Nonwovens have thus become a commodity without the compensating features of the metals industry which has its London Metals Exchange. 

 So, why not have an Exchange for Nonwovens where:

·        Prices are set twice a day

·        There's a transparent market for futures contracts which is settled daily between long and short positions

·        Contractual obligations can be hedged.

Hygienic Nonwovens – Structural Issues

Mikael Staal Axelson, General Manager, Personal Care, Fibertex (Denmark); Jose Durany, General Manager of Tesalca-99 (Spain) and Frantisek Klaska, Technical Director of Pegas (Czech Republic) co-authored this joint analysis of the structural challenges facing the hygienic nonwovens industry. 

 Their objectives were to:

·        Help and support the whole industry

·        To address the supply imbalance and favour improved market knowledge

·        To develop a sustainable business model for nonwovens producers within the supply chain.

The problem of overcapacity arose from the trend from carded thermal-bonded polypropylene staple to spunmelt fabrics for diaper construction.  Initially, high growth arising from the demand for textile-like backsheets and geographical expansion kept things in balance but in 2004 a major switch to spunmelt was required, and this coupled with a diaper design change in 2006 led to the standardisation of technology and products and the commoditisation of the last 2 years.

 Today the weight of nonwovens used in diapers is higher than it used to be despite basis weight reductions and diaper design changes.  In Europe the nonwovens industry is now mature but fragmented, capacity utilisation is poor (oversupply), average energy prices have doubled (97-07), polymer prices are volatile but generally rising, and the diaper producers specifications, with their demands for more sustainability, are getting harder to meet.  In the USA, there are fewer producers and a more balanced supply.  Latin America is moving to overcapacity; data from the Middle East and Africa is scarce, but in the Far East, demand is growing.

 In conclusion, the business model that has worked so far will not work in future and a new approach is required to assure the sustainability of the industry.  More transparency and conditions allowing more investment in R&D for higher value products is needed. This could possibly be achieved through EDANA or through alliances within the supply chain secured by agreements under EU competition law.

Panel Discussion

Aldo Ghira (Entrepreneur and former EDANA Board Member) facilitated a discussion session moderated by Ruxandra Cana, a partner of the Field Fisher Waterhouse LLC, (Belgium) law firm.  Also on the platform were the authors of the previous 2 papers, Kris Malowaniec (Hartmann), Bernard Kunze (Reicofil), M. van der Elst, and Pierre Wiertz.

 Mr Ghira listed possible discussion topics related to the last 2 presentations:

 ·        Is there a common understanding of innovation and technology?

·        Why are the most innovative nonwovens producers absent from diaper supply?

·        Is critical mass an issue?

·        Can raw material exposure risks be better managed?

o    LME analogy

o    Should spunmelt be toll-manufactured to neutralise raw material risks?

Comments made by the panel and the audience included:

·        You're analysis is right but So What.  This is normal evolution of a technology

·        We have a supply chain but no value chain

·        Innovation by Nonwovens Producers made disposable diapers possible, but their relegation to commodity supplier status is a normal progression.  It happened in metals, and paper.

·        Innovation is now dedicated to cost reduction. (but this is not innovation, it's just cost reduction.)

·        The entrepreneurs died out and left the industry to the financial men

·        Consumer needs had been interpreted by one converter with a vertically-integrated organisation and others had followed.

On Sustainability:

·        Moves to lower basis weights and energy recovery improved disposables.

·        The initial euphoria for bioplastics has gone.  “We're waiting for a wood-based plastic.”

On EDANA's possible contribution:

·        Could transparency be improved if EDANA circulated the Nonwoven Producers committee quarterly reports more widely?

·        Could EDANA become an innovation platform like EURATEX (automated clothing production R&D) and attract EU funding. (but only 2-3% of applications get a grant)

Summing up

Mr Ghira mentioned the need for more entrepreneurs within companies; a better understanding of consumer needs throughout the supply chain - for the non-vertical part of the chain; more transparency to avoid mistakes and, in general, just more co-operation in the supply chain.

Nanotechnology and Nonwovens

Helena Engqvist, Consultant, (Switzerland) defined Nano- as a term referencing particles smaller than 100nm or the size of the average virus.  Nanotechnology, according to the UK's Royal Society “involves the design, production and application of structures, devices and materials by controlling their size and shape at the nanometre scale”.  It was driven by EU and OECD sponsored programs, by governments, investment institutions and universities because it promised new products and new user benefits especially with regard to the 2015 UN Millennium goals for clean water and air. 

 A patent survey suggested the USA was leading the field, followed by Japan, Germany, South Korea, Taiwan, China, UK,France, Israel, and Russia. 

Activities include the development of:

·        Filters for construction, automotive cabin air and housing

·        Surgical products, wound care, drug delivery

·        Personal care, barrier fabrics, stretchable materials

·        Military, industrial, and sports clothing - repellancy

·        New machinery for making nanofibres and nonwovens

Risks posed by nanofibres are being evaluated.  Nanoparticles can get into the bloodstream and other organs via inhalation and are suspected to cause inflammation.  There are implications for REACh.

Toxicology of Nanomaterials

Hadjira Mezaiti, the Regulatory and Scientific Affairs Director of EDANA reviewed the discussions currently taking place at ISO and OECD on nanoparticle safety.  These target ascertaining the relative importance of their size, shape, surface topography, aggregation state and solubility in addition to their chemistry. No real thresholds of concern have been established yet despite 472 studies on 965 different nanoparticle types. 

 Most studies have been concerned with their cytotoxicity and mammalian toxicity.  In addition to inhalation risks, dermal, ingestion and intravenous exposures were being considered, but there was little data on human exposure.  Some studies suggested that inhaled particles may translocate from nasal mucosa to the brain, but most would reach the alveoli and then be transported by the mucociliary escalator into the gastro-intestinal tract.  Some may pass into the bloodstream from the alveoli. Some may penetrate into cellular mitochondria and the nucleus and interact directly with DNA.  They would be excreted from the GI tract in faeces, or from the blood in the urine via the kidneys or in the bile via the liver.  Transport times and retention times remain to be established. In vitro genotoxicity had been reported but attempted confirmation in -vivo was inconclusive. Carbon nanotubes have caused inflammation when similar in form to asbestos (long, fine, rigid fibres with no degradability.

 With regard to eco-toxicity, test methods were being developed.

 With regard to risk assessments, there were numerous national and international research projects underway.    EDANA has a full list.  The Swiss Federal Office of Public Health has classified nanomaterials into specific risk categories, and the SCENIHR (2007a) four-tier algorithm is in use for case by case, exposure driven evaluations.

 With regard to nano-specific regulations, there were none, but the EC had issued a Code of Conduct (Feb 2008) and a Communication (June 2008) on “Regulatory aspects of Nanomaterials”.  In January 2009 the European Parliament called for a resolution on the regulation of nanomaterials.

 Asked if well known natural nanomaterials such as colloids (e.g mayonnaise) should be excluded from regulation, Ms Mezaiti said there was no information yet.  New nanomaterials would, like drugs, be subjected to pre-market clearance.

Electrospun Nanofibres

Stanislav Petrik, Strategy and Business Development Director of Elmarco (Czech  Republic) pointed out that no dust or particles leave their nozzleless Nanospider production lines because the filaments are endless and the charged belt captures all fibres or particles in the air.  They use an electrode-to-belt potential difference of 30 to 120 kV, can process solutions of up to 20% polymer and typically produce a cloud of filaments in the 80-250 nm range.

 Air filtration is still the main application, where a tenth of a gsm (or less) layer of nanofibres gives a big increase in filtration efficiency with a tiny increase in pressure drop.  Here filtration performance depends mainly on the total length of nanofibres per square metre rather than their basis weight.  This Relative Fibre Length correlates well with pressure drop and filtration efficiency.

 Noise abatement applications are growing because the nanofibre webs are particularly efficient absorbers of low frequency sound.  AcousticWeb™  is made by applying a ~0.5gsm web of ~350nm PVA nanofibres to a 3.3-6.7 dtex polyester staple cardweb on a 1.6 metre wide production line with a double-doffer card and 4 Nanospider units each with 8 spinning chambers.

 Photocatalytic membranes use a nanoweb supporting and containing a nano-structured catalyst to guarantee safety.  A fibreglass substrate (18gsm) carries 20 gsm of photocatalyst in 0.7 gsm of polymer nanofibre, and this will remove volatile organics when the polluted air is passed through a UV chamber containing the filter.

 The nanofibres are also being used in the development of more efficient batteries and solar cells. Lithium titanate nanofibres were mentioned.

 In response to questions, Mr Petrik revealed that while the fibres were too large to display quantum effects, a new mechanism of filtration had emerged.  The very low pressure drops had been shown to be due to the fact than fluid velocities at the fibre surface were above zero.  Privately, he admitted that machine sales, other than laboratory lines, were very slow.  They nevertheless continue with a high level of R&D.

Filled Nanofibres

Laura Frazier, President of SNS Nanofibre Technology (USA) described the electrospinning of 100nm to 1000nm nanofibres from nozzles with diameters up to 1.5mm.  These big orifices (“pastry cones rather than hypodermic needles”) allowed easy incorporation of particulates, especially biological particulates which need low-temperature processes.  The particles were well retained and distributed uniformly throughout the webs.  Examples of added particulates were:

·        Pollen, encapsulated in PEO for spinning and then liberated by dissolution of the PEO

·        Lidocaine, alginates, spores, keratinocytes.

·        Tea tree oil, Waterlock 180 (SAP), erythromycin, and poly(HEMA) with rhodamine.

·        Silver sulfadizine, electrospun carbon fibres, gold nanoparticles, magnetic particles and zinc oxide.

·        Confectioners sugar

For the SAP loaded nanofibres, polyurethane was used to give elasticity, and the structure, containing a very high percentage of SAP absorbs rapidly without gel-blocking.  These Nanosan®Sorb composites absorb up to 40 g/gms of saline at room temperature.

 A vaso-dilatory patch which allowed controlled release of nitric oxide has been made from 4 layers as follows:

·        Top layer and 3^rd layer – PU nanofibres containing  SAP

·        2nd Layer – PU nanofibres with ascorbic acid

·        Bottom layer – PU nanofibres with Nitrite/Dowex

Ms Frazier acknowledged the contribution of the University ofAkron.

Nanoscale Coatings

Georg Bolte of Bolte Consulting (Germany) has developed a process using aerosols to apply nanoscale coatings.  A 0.5micron water-based aerosol produced by ultrasonic or piezo technology gives a 5nm coating which can be fixed to a polypropylene fibre when applied during a corona treatment of the nonwoven.  The aerosol is sprayed hot and condenses onto the cooler nonwoven in the coating chamber.  The coating is a monolayer with one end of the molecules bonded to the PP.  This monolayer is much more stable than conventional corona grafts.

The development appeared to have been initiated to provide a primer layer for UV printing inks, the illustrations being of the coating machinery on 2.7m wide printing machines.

Additives for Nonwovens

Regina Koppe, Technical Sales, Zschimmer and Schwarz (Germany) promoted possible uses of their finishes in nonwovens:

·        Lertisan NF 50 as a spin finish on PPS and PI fibres to improve carding and needling (Hot gas filtration)

·        Lertisan HD102 as a durable “wet on wet” hydrophilic finish on polyester or polypropylene spunlace fabrics, allowing viscose to be replaced in wet-wipes.  It also gives improved strike-through and wet-back in coverstocks.

·        Lertisan HE101 fluorocarbon for alcohol and blood repellency.

There were no questions.

Hot melt coating methods

Georg Gillessen, Sales Manager for Nordson Engineering (Germany) provided a guided tour of the company brochure, comparing slot coaters with wheel and screen, spray, and curtain coaters.  All were good in their own ways.  Apparently the next big thing will involve foaming the melt.

  Calvin Woodings

11 May 2009