Seventy-seven full presentations, twenty
sessions, a suppliers new technology showcase with a further fifteen short
papers, table-top displays, award ceremonies, and for TAPPI members numerous
committee meetings, had all been squeezed into two and a half days at a
delightfully sunny Baltimore harbourside loacation. The attendance, at around
350, was down on last years Dallas meeting (~500) and well below the combined
attendance of the lNDA and TAPPI technical conferences that this blockbuster has
replaced. With the delegates having to choose between three papers at any one
time, some of the speakers were certainly addressing smaller groups than the
quality of their presentations merited. But overall it worked, and INDA/TAPPI
are to be congratulated on cramming so much technical information into such a
short time. For all but those interested in the broad scope of the industry,
choosing between sessions should not have been difficult.
Key Points
- Wellman has developed a permanently hydrophilic polyester fibre from polyethylene glycol and terephtalic acid using branching agents to correct the spinnablity problems.
- Antimicrobials that release chlorine when challenged by microorganisms are now being commercialised. They can be permanently bonded to cellulose or synthetics and are activated by mild chlorine bleaching.
- Reiter Perfojet claimed that an improved “Swiffer” could be made by “Jetlace” hydroentangling of polyester to a “Perfobond” spunbonded PP. Cheaper, bulkier, stronger dusters resulted.
- Samples from a simple air-forming process making chef’s hats direct from a card were remarkably good and the process was now being commercialised. Many other shapes were possible
- Optimisation of thermal-bond fabric strength involves balancing failure of the bond itself with failure of the fibres within two fibre diameters of the bond.
Microdenier Spunbonds Fumin Lu of Ason
Engineering Inc defined microdenier as 1 denier and below and pointed
out that the high-speed spinning needed to achieve these deniers economically
inevitably meant higher filament orientation and stronger fibres and fabrics.
Ason's short-tube draw system allowed the filaments to flap around in turbulence
at the tube exit giving more “form drag” and hence a higher drawing force. At
400m/sec air speed this was said to be five times that achieved with a
conventional long laminar flow draw tube. Data from experiments with a range of
resin melt flow rates processed under identical spinning conditions
showed that increasing the MFR from 35 to 350 increased a15gsm fabric
hydrostatic head from 100 to 140 cms. However MD tensiles dropped from 2.3kgs to
1.7, CD tensiles fell from 1kg to 0.7kgs, % Crystallinity fell from 65 to 54,
crystal size fell from 23 to 20 angstroms and the pure monoclinic structure
obtained at 35 MFR was contaminated with smectic at 350MFR.
If the spinning conditions were optimised for each resin
so that they could be run at the same throughput , the denier reduction
(to 0.5 at the 6000m/min spin speed achieved with the 350MFR resin) allowed the
fabric hydrostatic head to increase from 150 to 207 cms. This enabled the 350
MFR resin to be converted at 11gsm to give the same HH as a 15gsm made from the
35 MFR resin. MD Tensiles fell from 2.8 kgs at 35 MFR to 2.2 kgs at 350 MFR.
Overall the 350 MFR resin (EOD39-60 from Atofina) gave the finest fibres and the
best hydrostatic heads with acceptable tensiles when converted on the Ason
machine.
Increasing Melt Flow Rates
Kimberly McLoughlan of Sunoco had also
examined the relationship between increasing MFR and reducing tensiles having
ensured that changes in MFR did not affect the Molecular Weight Distribution in
the resin. Resins with MFR's from 19 to 188 with similar MWD's were converted on
a Reicofil II system to give 2.5 denier fibres and 17 and 30 gsm fabrics. Over
the MFR range, 30 gsm fabric tensiles fell by 70% despite filament strengths
declining by only 13%. The optimum bonding temperature was significantly lower
at the high MFI, and this lower crystallinity polymer appeared to form better
bonds with flatter fibres. So why were the fabric tensiles so low? Dr Mc
Loughlan postulated that as the bonds were stressed, the flatter filaments
rupture more easily at the edge of the bonded areas.
Metallocene PP Spunbonds
Gajanan S Bhat of UTK compared PP
spunbonds made from the conventional Ziegler-Natta resins and the newer
metallocene catalysed isotactic varieties. Fabrics and filaments made from each
type three different production rates were tested for tensiles, and structural
properties.
• Both polymer types ran well on the Tandec Reicofil
(“somewhere between I and II”) system.
• Metallocene PP (mPP) gave higher filament strengths (67g/tex versus 25g/tex at the highest throughput) and lower filament elongations (120% v. 296%), but also lower crystallinity and birefringence.
• The mPP fabrics had maintained these higher tensiles over a wider range of bonding temperatures.
• This strength advantage was due to the stronger filaments, the better-formed thermal bonds, and an apparently reduced degradation of filaments at the bond edges.
• Metallocene PP (mPP) gave higher filament strengths (67g/tex versus 25g/tex at the highest throughput) and lower filament elongations (120% v. 296%), but also lower crystallinity and birefringence.
• The mPP fabrics had maintained these higher tensiles over a wider range of bonding temperatures.
• This strength advantage was due to the stronger filaments, the better-formed thermal bonds, and an apparently reduced degradation of filaments at the bond edges.
Dr Bhat thought the benefits arose from the better
control of molecular weight distribution in PP manufacture by the metallocene
route.
Thermal Bond Failure
Stephen Michielsen of Georgia Tech has
investigated how the properties of PP fibres change in thermal bonding. If
fibres are to bond, the molecular chains must have the mobility and the time to
flow from one fibre into another at the bonding point. In theory, the chains are
mobile above the glass transition temperature so PP fibres should bond on
contact at room temperature. In fact the PP chains are immobilised by
crystallinity and heat input is required to melt the crystals before true
mobility can arise. When crystals melt, the birefringence and the density of the
fibre should change, so there will be a morphology gradient from unbonded
fibres, through the bridging region and into the bond point. These changes have
now been observed using polarised laser Raman microspectroscopy. This technique
allows 1 micron resolution and has been used to make multiple measurements in
the region of two fibre diameters outside the bond edge. It has shown that the
birefringence (and hence the fibre strength) decreases by half in this region,
and this loss of strength diminishes as the speed through the calender
increases. With polypropylene the polymer density increases into the bond
itself, whereas with polyester, which is reluctant to recrystallise, it
decreases. Dr Michielsen concluded that there is a trade off between bond
strength and fibre strength at the bond edge, and that the optimum results would
be obtained when half of the bonds failed internally and half failed due to
fibre breakage at the bond edge. Asked about the effects of denier he felt that
heat diffusion rate into the fibre was the key. Thicker fibres would be slower
to heat up, but the bond edge region - defined as 2 fibre diameters from the
bond edge - would still be important.
Bicomponent Technology
Hans Georg Geus of Reifenhauser GmbH
reminded us that bicomponent fibre production required careful
adaptation of resin rheology to prevent the two polymers having widely differing
stabilities at the extrusion temperature, and to prevent dissolution of one
polymer in the other. The technology was nevertheless established and the
markets were expected to grow although the magnitude of the growth was difficult
to estimate.
• Geotextiles and hygiene would be the main growth areas.
• PLA bico fibres would allow biodegradable spunbond and meltblown fabrics
• Unspinnable polymers could form the sheath on a spinnable core polymer.
• Meltblown bico's were more difficult because the air jets modify the fibre shape uncontrollably.
• The Reicofil system used a stack of apertured plates in the spinneret, their selection defining the type of bico produced (sheath/core, side-by-side, segment-pie etc).
• Geotextiles and hygiene would be the main growth areas.
• PLA bico fibres would allow biodegradable spunbond and meltblown fabrics
• Unspinnable polymers could form the sheath on a spinnable core polymer.
• Meltblown bico's were more difficult because the air jets modify the fibre shape uncontrollably.
• The Reicofil system used a stack of apertured plates in the spinneret, their selection defining the type of bico produced (sheath/core, side-by-side, segment-pie etc).
Biodegradable polyester
Bill Haile of Eastman Chemical Co.
provided an update on the development of the Eastar Bio biodegradable
polyester.
• The relatively soft and elastic fibre was proving difficult to crimp and card and this was restricting its use as a staple fibre.
• The polymer was however useful in spunbond or meltblown or as a skin on PP or PET core bicomponent bonding fibres.
• It was being developed as a bonding fibre for hemp-based biocomposites.
• 10% of short-cut Eastar Bio in papermaking bonds the paper during normal drying and doubles the wet strength.
• Films based on the polymer have much better moisture vapour transmission rates than PE, so Eastman are trying to improve this property further.
• The polymer is more prone to hydrolysis in fibre spinning than PET, but careful attention to pre-drying the polymer can control this problem.
• The fibre has proved stable in normal use in textiles for over 3.5 years now.
• The fibre is not degraded by water per se, but the presence of water can allow bacteria to attach to the surface and these can commence the degradation process.
• The relatively soft and elastic fibre was proving difficult to crimp and card and this was restricting its use as a staple fibre.
• The polymer was however useful in spunbond or meltblown or as a skin on PP or PET core bicomponent bonding fibres.
• It was being developed as a bonding fibre for hemp-based biocomposites.
• 10% of short-cut Eastar Bio in papermaking bonds the paper during normal drying and doubles the wet strength.
• Films based on the polymer have much better moisture vapour transmission rates than PE, so Eastman are trying to improve this property further.
• The polymer is more prone to hydrolysis in fibre spinning than PET, but careful attention to pre-drying the polymer can control this problem.
• The fibre has proved stable in normal use in textiles for over 3.5 years now.
• The fibre is not degraded by water per se, but the presence of water can allow bacteria to attach to the surface and these can commence the degradation process.
Durably hydrophilic synthetics?
Mark Nehra of Uniquema reviewed the
issues in making synthetics durably hydrophilic. Additives in the dope failed
because the concentration had to be too high to be cost effective. Surface
treatments were generally too easily lost to be described as durable, the
exception being silicones which often caused problems in subsequent processing
or use. He felt their Cirrasol PP842 and PP843 finishes were the answer,
providing silicone performance in a silicone-free product. PP842 at 0.5% gave
strikethrough results below 7 seconds for at least 10 insults.
Hydrophilic Polyester
Keith Carnes of Wellman Inc. introduced
a new hydrophilic polyester (Sensura Ô ) which gave permanently enhanced wicking
along with enhanced thermal bond strengths, lower pilling, higher softness and
better dyeing without affecting sterilisability, stability, crimp, carding or
bulk. The new polymer was made by polymerising polyethylene glycol with
terephthalic acid, the problems of low melt viscosity and poor fibre spinning
inherent in this approach being solved by the use of branching agents. Varieties
of the new fibre for use in nonwoven, spun-yarn and filament-yarn fabrics had
been evaluated, the nonwoven versions (T870 and T289) by thermal bonding 50gsm
webs of 100% and 50/50 rayon blends on a 25% bonded-area calender.
• T289 gives similar strengths to PET but achieves them at 200 o C where PET requires 230 o C. Elongations of the T289 fabrics were however nearly double those of the PET.
• Tested as an acquistion distribution layer for multiple insult overflow, the T289 fabric gave a quarter of the overflow of the PET control at the first insult, but only 75% of the overflow at the third insult. (Wellman is now looking at air-laid routes to ADL's)
• 50/50 T289/rayon blends were more than 50% stronger than PET/rayon blends and had double the elongation.
• Demand wettability testing showed that the T289/rayon blend had three-times the capacity of PET/Rayon with the acquisition rate (measured after 20 seconds absorbtion) also being three times that of the control.
• T289 gives similar strengths to PET but achieves them at 200 o C where PET requires 230 o C. Elongations of the T289 fabrics were however nearly double those of the PET.
• Tested as an acquistion distribution layer for multiple insult overflow, the T289 fabric gave a quarter of the overflow of the PET control at the first insult, but only 75% of the overflow at the third insult. (Wellman is now looking at air-laid routes to ADL's)
• 50/50 T289/rayon blends were more than 50% stronger than PET/rayon blends and had double the elongation.
• Demand wettability testing showed that the T289/rayon blend had three-times the capacity of PET/Rayon with the acquisition rate (measured after 20 seconds absorbtion) also being three times that of the control.
T870 generally gave values half-way between the T289 and
PET in nonwovens. In knitted fabrics the T870 gave home-launder pilling levels
comparable to 100% cotton with a 14% improvement in drying time, a 34%
improvement in moisture vapour transmission, a 60% reduction in shrinkage and a
75% increase in perceived comfort!
The T801 filament yarn at 1.5 dpf was said to give the
same handle as a 0.6-0.75dpf PET yarn, along with a better dye uptake (20%)
shorter dyeing time (1.75hrs cf 2.75 hrs for PET) while maintaining better wash
fastness. Knitted fabrics dried 35% faster than PET, had 65% better stain
resistance, 70% better wicking and 270% better static dissipation.
Infuriatingly, the moderator did not allow questioning
of these remarkable claims and Mr Carnes disappeared before the end of the
session.
Hats off to UMIST
Hugh Gong of UMIST has developed a
pilot process to air-form chefs hats directly on moulds positioned after the
doffer of a card. He used bicomponent fibres and this paper reviewed the
conditions required to get the optimum through-air bonding. Samples of the hats
shown after the talk proved remarkably even and strong and were about to be
commercialised by the only chef's hat producer in the UK , who had sponsored the
work. He was dismissive about the achieving such good-looking products in such a
short and simple process, referring questioners to a recent International
Nonwovens Journal for a description of the details of the air-forming. He
thought the method could be used for a variety of other products, especially
filters and moulded garment interlinings (e.g bra cups) Marks and Spencers were
said to be taking an interest.
Antimicrobials I
Thomas Theyson of Goulston Technologies
reminded us that the Aegis Microprobe Shield silane-quat antimicrobial
is unconventional in that it is durably fixed to the fibre surface, not consumed
by microorganisms, does not encourage resistance to develop, gives no zone of
inhibition in the standard plate test, but kills a variety of bacteria and fungi
by “stabbing” its long alkyl chain through the cell wall. Furthermore it can be
mixed with the spin finish and a simple bromo-phenol blue stain test can show
whether or not it is still active.
Antimicrobials II
Robert Monticello of Aegis Environments
compared antimicrobial additives, making the following points:
• 61% of women now actively seek antimicrobial versions of products.
• Developing resistance to antimicrobials can “teach” bacteria how to resist antibiotics.
• A “pump action” mechanism of resisting antimicrobials is apparent: the bacteria simply recognises an invading substance and pushes it back out through its cell wall.
• Unconventional antimicrobials which do not leach and kill bacteria by a mechanical action were best. The silane quaternary ammonium compounds with a silanol group allowing permanent covalent bonding to the fibre and a quaternary ammonium group with a long alkyl chain (-Si-C 3 H 6 -N + -C 18 H 37 ) that could stab through the bacterial membrane were best.
• Antimicrobials with a long history of safe use such as their (originally Dow Corning technology) silane quats were to be preferred.
• ASTME 2149-01 was the preferred evaluation procedure for bacteria, and ASTM G21 was best for fungi.
• Being cationic, the silane quats react with bromophenol blue to give a blue color and are thus easily detected on surfaces.
Antimicrobials III
• 61% of women now actively seek antimicrobial versions of products.
• Developing resistance to antimicrobials can “teach” bacteria how to resist antibiotics.
• A “pump action” mechanism of resisting antimicrobials is apparent: the bacteria simply recognises an invading substance and pushes it back out through its cell wall.
• Unconventional antimicrobials which do not leach and kill bacteria by a mechanical action were best. The silane quaternary ammonium compounds with a silanol group allowing permanent covalent bonding to the fibre and a quaternary ammonium group with a long alkyl chain (-Si-C 3 H 6 -N + -C 18 H 37 ) that could stab through the bacterial membrane were best.
• Antimicrobials with a long history of safe use such as their (originally Dow Corning technology) silane quats were to be preferred.
• ASTME 2149-01 was the preferred evaluation procedure for bacteria, and ASTM G21 was best for fungi.
• Being cationic, the silane quats react with bromophenol blue to give a blue color and are thus easily detected on surfaces.
Antimicrobials III
Roy Broughton of Auburn University
provided a comprehensive update of his INTC 1999 paper on the methods
of making textiles antimicrobial and introduced some newer approaches involving
halogens. Chlorine for instance is a very broad spectrum, fast acting biocide
with an advantage over the more specific antimicrobials in that organisms cannot
develop a resistance to it. Despite the fact that it kills most life-forms and
is capable of reacting in nature to form some highly toxic compounds, the Auburn
group has funding from the National Textile Council to develop compounds that
retain chlorine, releasing it only when challenged by a micro organism. The
group has now published and patented approaches based on halamine chemistry,
more specifically chloramines such as hydantoin which provide kill ratios in
excess of 99% in a few minutes.
The first approach to getting these compounds into
products involved synthesising polymers specifically to support the chloramine
functionality. For instance hydantoin was attached to polystyrene in an
elastomer to make a drinking straw which purified water. Subsequently they
reacted the halamine with formaldehyde to provide a finish (methylol hydantoin)
which bonded to cellulosics as part of the permanent press finishing (DHDMEU)
chemistry. Mild (0.01%active chlorine) bleaching of the finished fabric
converted the hydantoin group into a chloramine thus activating the textile.
This approach has been used on cotton hospital sheets,
and here any loss of activity due to soiling is regenerated each time the sheets
are washed and bleached.
For synthetics, the fibre surface has to be activated
before the hydantoin can be attached: nylon needed formaldehyde pre-treatment
and polyester requires ammonia. Again, once the hydantoin is attached a mild
bleaching activates it. After applying a 9 log innoculum of staph. aureus to the
polyester a 5 log kill was observed in 10 minutes and a 7 log kill in 20
minutes.
Halosource (Seattle) were said to be
among a number of companies commercialising this halamine technology. In an
aside on the use of chitosans as absorbable antimicrobials, Dr Broughton
stressed the need for extreme levels of purity in the crab shell extract to
avoid proteins known to cause allergic reactions contaminating the dressings.
Faster Carding
Sigfried Bernhardt of Spinnbau reviewed
the developments in high speed carding in order to identify further bottlenecks.
Carding, widely assumed to be incapable of further development when
50kg/hr/metre was reached in 1980, was now providing 300kg/hr/metre on
commercial systems thanks to increasing roller speeds, more precision in
settings, better clothing, better drives and the use of suction transfers and
turbulence control. A quality/productivity compromise arises because improving
web quality needs more working points and more compaction between cylinders and
doffers both of which means the fibre has to stay longer in the card.
Better quality and hence higher potential output could
for instance be obtained by carding, cross-folding, and then feeding the output
of the cross-folder to yet another card. For high speed coverstock production
the current state of the art was a double doffer system with belts and vacuum
transfers on each doffer giving a potential 400kgs/hour/metre, or 400 metre/min
operation at 15gsm. Air-layers, giving full dispersion of staple fibres in an
airstream prior to laydown with a 1:1 MD/CD ratio could be added to a line after
carding, but these were currently unable to work at lightweights without web
drafting which still tended to spoil the quality as well as the MD/CD ratio. The
more voluminous webs from these systems were more difficult to handle at higher
speed. This type of airlay was currently restricted to 80 m/min.
Staple Fibre Air-Laying
Michel Collotte of NSC Nonwoven System Thibeau
gave the first presentation of their new Air-web Ô staple fibre air-lay
system. This would produce MD/CD ratios of less than 1:1.5 from 10-40mm fibres
at up to 260 kg/hr/m in basis weights from 35 to 200gsm. Like the Fehrer,
Hergerth and Chicopee air-lay systems also described, it needed to be fed by a
card and appeared limited to about 80m/min web speed at 40 gsm. Its main
application currently was make-up removal pads.
Scrim Reinforcement I
Ed Hovis of AET Speciality Nets and Nonwovens
promoted the range of apertured nets made by melt-embossing and
counter-rotating dye processes now available for filtration, healthcare and
textile applications. Melt-embossed nets were made by calendaring a film then
stretching it to open up perforations between oriented film “filaments”
connecting the embossed areas. Many different geometries are possible from a
variety of polymers (mainly PP, PE and copolymers) with hole sizes varying from
about 50 to about 800 microns and with open areas between 15 and 65% comprising
up to 1600 holes/square inch. Thicknesses vary from 2 to 17mils, with
bicomponency achievable by coextruding a two-layer film from two different
polymers. MD-only stretching gives low open area but well-defined flow
channelling. Pattern definition is best with HDPE, worse with PP, and a
perforated film without obvious filament interconnections is obtained with soft
polymers like polyurethane. Counter-rotating dye technology gives tubular
diamond-pattern nets from a variety of polymers that are used to reinforce
filters and other fabrics.
Scrim Reinforcement II
Keith Misukanis of Conwed Plastics
described an experiment using their extruded PP scrims to reinforce
hydroentangled polyester. Three net types and three weights of 1.6dpf Dacron PET
were combined by HE and compared with hydroentanglement of the PET alone. The
nets were all 4 threads per inch in both directions and varied in basis weight.
(20, 40 and 80 gsm). Measurements of tensile, tear and air permeability showed
that the composites tensile and tear properties were dominated by the scrim
properties, whereas the air-permeability was unaffected by the scrim.
Replacing Scrim with Spunbond
Daniel Feroe of Rieter-Perfojet made a
case for replacing the apertured net reinforcement of a Swiffer Ô -
like dry duster with a spunbond reinforcement. Perfojet Jetlace could
be used to hydroentangle polyester staple to a Perfobond spunlaid PP fabric. At
2.2 dpf the output of a single-beam Perfobond spunlaid line would be 300 kg/hr/m
and therefore well matched to the output of a Jetlace line. With the PP spunbond
reinforcement, the wipe is twice as strong as the net-reinforced products now on
the market, with 20% better bulk and a 45% better ability to take a static
charge. Wiping tests suggest the dust capture capability of the
spunbond-reinforced product is between 40 and 100% up on the current commercial
products. Cost calculations showed that the Perfojet approach would require a
production line costing 30million Euro (50% more than the current process) but
would produce 16722 tonnes/year of saleable product compared with 12602
tonnes/year from the present process. On a per kilo basis, the spunbond
reinforced product would cost 1.69 Euros compared with 2.89 Euros for the
net-reinforced version.
Latex and thermal bonding revisited
Alfred Watzl of Fleissner Gmbh reviewed
their chemical and thermal bonding equipment in the context of using it to
upgrade fabrics made on their hydroentanglement systems. Points of
interest:
• 250,000 tonnes of HE fabrics were made in 2000.
• Lightweight webs were best bonded with foamed latex, on-line.
• Heavyweight webs were best bonded off-line with foam or liquid binders.
• The biggest Fleissner HE line for card webs was 5m wide running at 250-300m/min.
• The biggest Fleissner HE line for spunbond was 5.5m wide running at 500 m/min.
• 250,000 tonnes of HE fabrics were made in 2000.
• Lightweight webs were best bonded with foamed latex, on-line.
• Heavyweight webs were best bonded off-line with foam or liquid binders.
• The biggest Fleissner HE line for card webs was 5m wide running at 250-300m/min.
• The biggest Fleissner HE line for spunbond was 5.5m wide running at 500 m/min.
Stretching Spunlaced PTT
Donald Schiffler of the Nonwovens Cooperative
Research Centre, NCSU compared the stretch, recovery and compressive
behaviour of plain and apertured HE fabrics made from polytrimethylene
terephthalate (PTT) fibres and conventional PET. Being a soft fibre, PTT is
easier to entangle and gives a microdenier handle at normal filament deniers. It
recovers better from 10% strain, especially in apertured fabric form, but shows
little difference in recovery from compression. The apertured PTT fabrics were
also perceived as the softest. 50/50 PTT/PET fabrics showed a large and
currently inexplicable increase in fabric thickness.
Julian Jensen of Eastman Chemicals Co.
described their reinvolvement with fibres as a supplier of specialty
resins to the fibre industry. They would never again produce fibres themselves
but felt their history in the field enabled them to serve their fibre-producing
customers better than most. He listed the specialities as:
• Eastar Bio, the biodegradable polyester resin (see later)
• The low IV homopolymer for spunbond and meltblow processes
• PCT (poly-cyclohexane terephthalate) high melting point fibres
• PCTA – acid modified for filament production
• Various additives and concentrates.
• Eastar Bio, the biodegradable polyester resin (see later)
• The low IV homopolymer for spunbond and meltblow processes
• PCT (poly-cyclohexane terephthalate) high melting point fibres
• PCTA – acid modified for filament production
• Various additives and concentrates.
Ronald Pangrazi of Air Products Polymers
introduced three new experimental binders:
• Airflex HTP, a Vinyl Acetate Ethylene copolymer with high temperature resistance allowing it to perform like an epoxy up to 120 o C. It was free of formaldehyde and alkyl phenylethoxylate and could be applied by all techniques. The target application was mould release.
• Airflex LTC, a VAE copolymer which cured fully at 65 o C. This was also APE free and could be made formaldehyde free if required. It could be used to bond low-melt fibres or save energy or increase line speeds.
• Airflex IAS, a VAE copolymer with increased adhesion to synthetics to give higher wetstrength nonwovens. Compared with the standard Airflex 105 binder this increased wet strength from 500 to 840 gms/5cms. It was intended for use on multi-bond airlay lines or for reinforcing PET/Rayon blends.
• Airflex HTP, a Vinyl Acetate Ethylene copolymer with high temperature resistance allowing it to perform like an epoxy up to 120 o C. It was free of formaldehyde and alkyl phenylethoxylate and could be applied by all techniques. The target application was mould release.
• Airflex LTC, a VAE copolymer which cured fully at 65 o C. This was also APE free and could be made formaldehyde free if required. It could be used to bond low-melt fibres or save energy or increase line speeds.
• Airflex IAS, a VAE copolymer with increased adhesion to synthetics to give higher wetstrength nonwovens. Compared with the standard Airflex 105 binder this increased wet strength from 500 to 840 gms/5cms. It was intended for use on multi-bond airlay lines or for reinforcing PET/Rayon blends.
Disruptive technology?
D K Smith of Smith, Johnson Associates
reviewed methods of using the US Patent database to spot disruptive and
innovative technologies. 3D patent maps, patent genealogy trees, and patent
citation analysis could provide worthwhile insights into the direction of
development in an industry. However companies recognised this and some took
steps to obscure their lines of interest by assigning to remote subsidiaries,
covering non-critical aspects, or taking out many narrow patents. Others didn't
patent at all preferring total secrecy.
The US patent office currently issued around 3000
patents a week; 700,000 from 1996 through 2000. Of these 6657 dealt with
nonwovens, and 403 with nonwoven manufacturing processes.
• 52 US companies had filed nonwoven process patents in the 5 year period compared with 1 British company and 9 German companies. There were no patents from the world's biggest nonwoven producer, Freudenberg .
• Kimberly Clark led the table with 122 patents, followed by P&G (41), 3M (24), Dupont (21), Fiberweb Group (15) and J&J (7)
• 52 US companies had filed nonwoven process patents in the 5 year period compared with 1 British company and 9 German companies. There were no patents from the world's biggest nonwoven producer, Freudenberg .
• Kimberly Clark led the table with 122 patents, followed by P&G (41), 3M (24), Dupont (21), Fiberweb Group (15) and J&J (7)
Dr Smith had chosen 10 process types and assigned each
patent to one of these types:
• Lamination (23.3%) emerged as the biggest category, with Spunbond next (21.8%) and then Meltblown (15.6%)
• There were surprisingly few hydroentangling (8.9%) and pulp air-lay (2.8%) patents, and perhaps more than expected on the old dry-lay process (12.8%).
• Analysis of numbers by year showed that hydroentangling patents were steadily increasing (11 in 2000), while lamination patents had peaked at 31 in 1998 and had fallen to 15 in 2000.
• Total nonwoven process patents were down from 96 in 1998 to 67 in 2000.
• Other than combining nonwoven processes to make new materials the other significant trends involved making nonwovens more elastic, more biodegradable and more flushable.
• Lamination (23.3%) emerged as the biggest category, with Spunbond next (21.8%) and then Meltblown (15.6%)
• There were surprisingly few hydroentangling (8.9%) and pulp air-lay (2.8%) patents, and perhaps more than expected on the old dry-lay process (12.8%).
• Analysis of numbers by year showed that hydroentangling patents were steadily increasing (11 in 2000), while lamination patents had peaked at 31 in 1998 and had fallen to 15 in 2000.
• Total nonwoven process patents were down from 96 in 1998 to 67 in 2000.
• Other than combining nonwoven processes to make new materials the other significant trends involved making nonwovens more elastic, more biodegradable and more flushable.
Speed trap
Brian Osmondson of TSI Inc . promoted
their laser-doppler velocimeter which could measure the speed of anything to
within 0.1% without touching it. In addition to the obvious uses in law
enforcement and nonwovens production the machine had been successfully used to
measure the velocity profile of a filament between its emergance from a
spinnerette and stretching.
Worthless images
Norman Lifschutz of Hollingsworth and Vose,
along with other TAPPI menbers, had been trying to use a digital
imaging technique to measure the length and diameter of glass microfibres
simultaneously. The different labs were failing to get the same answers from the
same fibres and Dr Lifshutz had concluded that the results were a function of
the pixel size used in digital imaging. The technique has been declared
valueless and no further work is planned.
Winding-up
Alessandro Celli of A.Celli SpA pointed
out that in the now fiercely competitive environment of a mature nonwovens
industry high speed was an essential component of all business activities, not
just production. Current commercial production speeds were said to be:
• 150-200 m/m for carded spun lace lines
• 200-250 m/m for airlaid pulp lines
• 400 m/m for carded PP thermal bond lines
• 700-800m/m for spunbond lines.
• 150-200 m/m for carded spun lace lines
• 200-250 m/m for airlaid pulp lines
• 400 m/m for carded PP thermal bond lines
• 700-800m/m for spunbond lines.
His super winders could run at 1000m/min and cope with
all these, collecting jumbo rolls from the production line and automatically
transferring them for off-line high speed inspection, slitting and rewinding.
Points from other Papers
S S Ramkumar of Texas Tech had been
using the Instron and sledge method of measuring fabric surface friction and was
promoting this as a simple way of quantifying the handle of nonwoven fabrics.
Correlation of the technique with real handle assessments however remains to be
made.
Michael Thomason of BBA reviewed INDA,
EDANA, ISO and ASTM methods and pointed out that ASTM D5035 gave consistently
higher values for tensile strength than ISO 9073-3.
Austin Robinson of Maier America LLC
had developed cooled bearings for thermal-bonding calenders which
allowed hot-oil machines to work reliably at 300 to 400 o C.
LarryWadsworth of TANDEC was hoping to
acquire new Reicofil spunbond equipment and a new 12” meltblown line.
Andrey Troshko of Fluent Inc. presented
a computer analysis of air flow and fibre accumulation in a fluff-pad machine.
While the graphics were interesting, as yet no attempt had been made to
correlate it with any data from a practical machine.
Footnote: This report covers only the
papers attended. Summaries of those simultaneously presented papers reprinted on
the CD-ROM of the conference will be prepared shortly (see below). Attendance
(~350) was down on last years meeting and below the levels of the last combined
INDA and TAPPI technical conferences that it has replaced.
INTC 2001 CD-ROM Contents
(Provided by INDA)
Process Technology I
Advances in Microdenier Spunbond Technology Fumin Lu, Ason Engineering, Inc.
Effect of Polypropylene Melt Flow Index on Spunbond Fabric Strength Kimberly McLoughlin, Ph.D., Sunoco Chemicals
New Developments in Bicomponent Spunbond and Bicomponent Melt Blown Hans GeorgGeus, Reifenhäuser GmbH & Co.
Spunbonding Studies with Propylene Polymers Gajanan Bhat, Ph.D., The University of Tennessee
“Terminal Velocity” Is This All About Nonwovens? Alessandro Celli, Ph.D., A. Celli S.p.A.
Filtration
Activated Carbon Felt Implementation for Indoor Air Quality Improvement Valérie Héquet, Ph.D., Ecole des Mines de Nantes
Nonwoven Material Performance in Air Filtration Applications B. Dean Arnold, Kimberly-Clark Corp. USA
Gradient Density Filter Media for Liquid Applications Ganesh Deka, Kimberly-Clark Corp, USA
Low Emission Phenolic for Oil Filter Paper Wayne R. Walisser, Borden Chemical
Fast Evaluation of Average Fiber Diameters of Nonwovens Akshaya Jena, Ph.D. PMI, Inc.
Process Technology II
The Development of, and Opportunities for, Bi-component Melt Blowing Technology John Hagewood, Hills, Inc.
Understanding the Melt Blowing Process Randall R. Bresee, Ph.D., The University of Tennessee
Development and Characterization of Poly(Trimethylene Terephthalate) Based
Bicomponent Meltblown Nonwovens Dong Zhang, Ph.D., TANDEC
Applications of Melt-spun Hollow Fibers in Nonwoven Structures Robert Shambaugh, Ph.D., University of Oklahoma
Performance Analysis of Meltblown Dies Using Computational Fluid Dynamics Aniruddha Mukhopadhyay, Fluent, Inc.
Process-Properties Study of Melt Blowing Polyurethane for Elastic Military Protective
Apparel Garments Larry C. Wadsworth, Ph.D., TANDEC
Finishes & Surfaces
Effect of Finish Uniformity on Friction and Antistatic Protection of Polypropylene Yarn Thomas Theyson, Ph.D., Goulston Technologies, Inc.
Role of Fiber Finish in the Conversion of Fiber to Nonwovens: Finish Performance as a
Mechanical Processing Aid in Needlepunching Abdelfattah M. Seyam, Ph.D., NCRC
Surface Modification of Wool Fibers with Enzymes Gisela Buschle-Diller, Ph.D., Auburn University
Rayleigh Instability Development in Fiber Finishing Eunkyoung Shim, Ph.D., NCRC
Interaction of Liquid Sprays with Nonwovens Yashavanth Kamath, Ph.D., TRI/Princeton
Barriers
Transport Properties of Electrospun Nonwoven Membranes Heidi Schreuder-Gibson, Ph.D., US Army Natick Soldier Center
Novel Linear Low Density Polyethylene Resins for Improved Breathable Microporous
Films Wes. R. Hale, Eastman Chemical Co.
Surgical Drape and Gown Performance Standards Joseph Palomo, Allegiance Healthcare Corp.
Development of Antimicrobial Nonwoven Fabrics--A Study Sabita Baruah, Ph.D., SNDT-Women's University, Mumbai
A Comparison of Antimicrobials for the Nonwovens Industry Robert Monticello, Ph.D., AEGIS Environments
Process Technology III
Where is the “bottle neck” at High Speed Lines? (Comparison of High Speed Lines) Dipl.-Ing. Siegfried Bernhardt, Spinnbau GmbH
Calender Processes in the Nonwoven Industry Ralf Quack, KTM Kleinewefers
An Investigation on Needling Parameters of Moldable Nonwoven Fabrics Produced From
Blended Thermoplastic Fibers Subhas Ghosh, Ph.D., Institute of Textile Technology
The Future of Cards & Airlay and the Future of Batt Forming Michel Collotte, NSC Nonwoven Systems Thibeau
Polymers & Fibers
Polyester Fibre Additives in Paper Making B.E. van Issum, Ph.D., DuPont (ret.)
A Hydrophilic Fiber with the Performance of Polyester Keith J. Carnes, Wellman, Inc.
Stretch, Recovery, Compressive Behavior and Property Tradeoffs for Hydroentangled
Fabrics of Poly(Trimethylene Terephthalate) Staple Donald Shiffler, Ph.D., NCSU
Fibers with “Potential” Glen Reese, KoSa
Effect of Preneedling on the Properties of Hydroentangled Fabrics Idris Ahmed, Ph.D., University of Leeds
Engineering Polymers in Nonwovens, Fibers & Other Extruded Substrates—Processing
and Applications for Polyphenylene Sulfide and Thermoplastic Polyesters Ramesh Srinivasan, Ticon
On-Line Measurements
On-Line Measurement of Nonwoven Weight Evenness Using Optical Methods Hung-Jen Chen, Ph.D., China Textile Institute
Determining Basis Weight Uniformity in Nonwovens: Part 1---Off-Line Methods Behnam Pourdeyhimi, Ph.D., NCRC
Process Technology IV
Apertured Nets—Overview of Non-Fiber Based Non-wovens Ed Hovis, AET Specialty Nets & Nonwovens
Computer Analysis of Air Flow and Fiber Accumulation in a Fluff Pad Machine Andrey Troshko, Fluent, Inc.
Manufacturing a Better Wiping Fabric Daniel Feroe, Rieter Perfojet
Investigation of Flow Characteristics & Geometrical Effects in Hydroentangling Jets E. Ghassemieh, Ph.D., Loughborough University -Speaker Cancelled
Spunlace Nonwovens - Upgrading by Binder Bonding and Thermofusion Alfred Watzl, Fleissner GmbH & Co.
Pneumatic Waste Material Conveying Systems for Nonwoven Applications Gordon Cole, Quickdraft
Mats & Insulation The Effect of Polymer Types and Fibrous Structure on the Thermal Insulation Properties
of Nonwoven Mats Peter P. Tsai, Ph.D., TANDEC
Nonwoven Fabrics in Roofing, in North America Nicholas S. Newman, Ph.D., N. Newman Associations
Advances in Latex Modification of Urea Formaldehyde Resins Wayne Miller , H.B. Fuller Co.
Reducing Variability in a Shingle Mimic Process to Aid in the Development of Better
Materials for the Roofing Market Dennis R. Brown, Owens Corning
Determining Latent Formaldehyde in Fiberglass Mat Stacy Wertz, Georgia-Pacific Resins, Inc.
Absorbents
SNAPs: A Safe and Natural Alternative to SAPs—The New Generation of Superabsorbents Serge Huppé, Lysac Technologies, Inc.
Needlepunched Nonwovens from Cotton Fibers for Absorbent Products Maria Zamfir, Ph.D., Technical University of Iasi
Development of Highly Absorbent Cotton-Core Nonwovens Edward (Mac) McLean, Cotton, Inc.
Sustainability
New Biodegradable Copolyester for Fibers and Nonwovens W.A. Haile, Eastman Chemical Co.
Biodegradable Nonwovens—Natural and Polymer Fibers, Technology, Properties Dieter H. Mueller, Ph.D., BIK-University of Bremen
Sustainability Through 100% Resin Usage Bob Hawkins, Munchy Ltd.
Renewable Nonwoven Composites for a Sustainable Future Matthew W. Dunn, Philadelphia University
Biosoluble Glass Fiber For Use in Ultrafine Diameter Filtration Products Jon F. Bauer, Johns Manville Co.
Properties & Performances
Compressibility of Perpendicular-Laid Fabrics Containing Cotton D.V. Parikh, Ph.D., SCRC/USDA
Introduction of Plastic Net Scrim to Alter the Properties of a Hydroentangled Nonwoven Keith Misukanis, Conwed Plastics
Rapid Morphology (Property) Changes at Bond Edge in Thermal Point-bonded
Nonwovens Stephen Michielsen, Ph.D., Georgia Institute of Technology
Predication of Performance in Thermally Pointed Bonded Nonwovens H. S. Kim, Ph.D., NCRC
INDA Standard Test Methods Update and Comparison to EDANA, ISO & ASTM Michael Thomason, Ph.D., BBA Nonwovens
The Simultaneous Measurement of the Diameter and Length of Glass Microfiber Norman Lifshutz, Ph.D., Hollingsworth & Vose
Evaluation of Hand Characteristics of Nonwoven Fabrics Using Simple Methods S. S. Ramkumar, Ph.D., Texas Technical University
3D Shell Nonwovens: Properties and Characteristics Hugh Gong, Ph.D., UMIST
Binders & Additives
Incorporation of Antimicrobial Materials in Fabric Roy M. Broughton, Jr., Ph.D., Auburn University
Faster and Better - How Radio Frequency Drying Can Improve Both the Speed and
Quality of Your Nonwoven Process Ben Wilson, PSC, Inc.
Development of Halogen-Free Flame Retardant Melt Spinning Nonwovens Christine (Qin) Sun, Ph.D., TANDEC
Advances in Nonwoven Highloft Binders Represented By New Acrylic/Vinyl Chloride
Emulsion Polymers Martin A. Cohen, Ph.D., BF Goodrich Performance Materials
Process Technology I
Advances in Microdenier Spunbond Technology Fumin Lu, Ason Engineering, Inc.
Effect of Polypropylene Melt Flow Index on Spunbond Fabric Strength Kimberly McLoughlin, Ph.D., Sunoco Chemicals
New Developments in Bicomponent Spunbond and Bicomponent Melt Blown Hans GeorgGeus, Reifenhäuser GmbH & Co.
Spunbonding Studies with Propylene Polymers Gajanan Bhat, Ph.D., The University of Tennessee
“Terminal Velocity” Is This All About Nonwovens? Alessandro Celli, Ph.D., A. Celli S.p.A.
Filtration
Activated Carbon Felt Implementation for Indoor Air Quality Improvement Valérie Héquet, Ph.D., Ecole des Mines de Nantes
Nonwoven Material Performance in Air Filtration Applications B. Dean Arnold, Kimberly-Clark Corp. USA
Gradient Density Filter Media for Liquid Applications Ganesh Deka, Kimberly-Clark Corp, USA
Low Emission Phenolic for Oil Filter Paper Wayne R. Walisser, Borden Chemical
Fast Evaluation of Average Fiber Diameters of Nonwovens Akshaya Jena, Ph.D. PMI, Inc.
Process Technology II
The Development of, and Opportunities for, Bi-component Melt Blowing Technology John Hagewood, Hills, Inc.
Understanding the Melt Blowing Process Randall R. Bresee, Ph.D., The University of Tennessee
Development and Characterization of Poly(Trimethylene Terephthalate) Based
Bicomponent Meltblown Nonwovens Dong Zhang, Ph.D., TANDEC
Applications of Melt-spun Hollow Fibers in Nonwoven Structures Robert Shambaugh, Ph.D., University of Oklahoma
Performance Analysis of Meltblown Dies Using Computational Fluid Dynamics Aniruddha Mukhopadhyay, Fluent, Inc.
Process-Properties Study of Melt Blowing Polyurethane for Elastic Military Protective
Apparel Garments Larry C. Wadsworth, Ph.D., TANDEC
Finishes & Surfaces
Effect of Finish Uniformity on Friction and Antistatic Protection of Polypropylene Yarn Thomas Theyson, Ph.D., Goulston Technologies, Inc.
Role of Fiber Finish in the Conversion of Fiber to Nonwovens: Finish Performance as a
Mechanical Processing Aid in Needlepunching Abdelfattah M. Seyam, Ph.D., NCRC
Surface Modification of Wool Fibers with Enzymes Gisela Buschle-Diller, Ph.D., Auburn University
Rayleigh Instability Development in Fiber Finishing Eunkyoung Shim, Ph.D., NCRC
Interaction of Liquid Sprays with Nonwovens Yashavanth Kamath, Ph.D., TRI/Princeton
Barriers
Transport Properties of Electrospun Nonwoven Membranes Heidi Schreuder-Gibson, Ph.D., US Army Natick Soldier Center
Novel Linear Low Density Polyethylene Resins for Improved Breathable Microporous
Films Wes. R. Hale, Eastman Chemical Co.
Surgical Drape and Gown Performance Standards Joseph Palomo, Allegiance Healthcare Corp.
Development of Antimicrobial Nonwoven Fabrics--A Study Sabita Baruah, Ph.D., SNDT-Women's University, Mumbai
A Comparison of Antimicrobials for the Nonwovens Industry Robert Monticello, Ph.D., AEGIS Environments
Process Technology III
Where is the “bottle neck” at High Speed Lines? (Comparison of High Speed Lines) Dipl.-Ing. Siegfried Bernhardt, Spinnbau GmbH
Calender Processes in the Nonwoven Industry Ralf Quack, KTM Kleinewefers
An Investigation on Needling Parameters of Moldable Nonwoven Fabrics Produced From
Blended Thermoplastic Fibers Subhas Ghosh, Ph.D., Institute of Textile Technology
The Future of Cards & Airlay and the Future of Batt Forming Michel Collotte, NSC Nonwoven Systems Thibeau
Polymers & Fibers
Polyester Fibre Additives in Paper Making B.E. van Issum, Ph.D., DuPont (ret.)
A Hydrophilic Fiber with the Performance of Polyester Keith J. Carnes, Wellman, Inc.
Stretch, Recovery, Compressive Behavior and Property Tradeoffs for Hydroentangled
Fabrics of Poly(Trimethylene Terephthalate) Staple Donald Shiffler, Ph.D., NCSU
Fibers with “Potential” Glen Reese, KoSa
Effect of Preneedling on the Properties of Hydroentangled Fabrics Idris Ahmed, Ph.D., University of Leeds
Engineering Polymers in Nonwovens, Fibers & Other Extruded Substrates—Processing
and Applications for Polyphenylene Sulfide and Thermoplastic Polyesters Ramesh Srinivasan, Ticon
On-Line Measurements
On-Line Measurement of Nonwoven Weight Evenness Using Optical Methods Hung-Jen Chen, Ph.D., China Textile Institute
Determining Basis Weight Uniformity in Nonwovens: Part 1---Off-Line Methods Behnam Pourdeyhimi, Ph.D., NCRC
Process Technology IV
Apertured Nets—Overview of Non-Fiber Based Non-wovens Ed Hovis, AET Specialty Nets & Nonwovens
Computer Analysis of Air Flow and Fiber Accumulation in a Fluff Pad Machine Andrey Troshko, Fluent, Inc.
Manufacturing a Better Wiping Fabric Daniel Feroe, Rieter Perfojet
Investigation of Flow Characteristics & Geometrical Effects in Hydroentangling Jets E. Ghassemieh, Ph.D., Loughborough University -Speaker Cancelled
Spunlace Nonwovens - Upgrading by Binder Bonding and Thermofusion Alfred Watzl, Fleissner GmbH & Co.
Pneumatic Waste Material Conveying Systems for Nonwoven Applications Gordon Cole, Quickdraft
Mats & Insulation The Effect of Polymer Types and Fibrous Structure on the Thermal Insulation Properties
of Nonwoven Mats Peter P. Tsai, Ph.D., TANDEC
Nonwoven Fabrics in Roofing, in North America Nicholas S. Newman, Ph.D., N. Newman Associations
Advances in Latex Modification of Urea Formaldehyde Resins Wayne Miller , H.B. Fuller Co.
Reducing Variability in a Shingle Mimic Process to Aid in the Development of Better
Materials for the Roofing Market Dennis R. Brown, Owens Corning
Determining Latent Formaldehyde in Fiberglass Mat Stacy Wertz, Georgia-Pacific Resins, Inc.
Absorbents
SNAPs: A Safe and Natural Alternative to SAPs—The New Generation of Superabsorbents Serge Huppé, Lysac Technologies, Inc.
Needlepunched Nonwovens from Cotton Fibers for Absorbent Products Maria Zamfir, Ph.D., Technical University of Iasi
Development of Highly Absorbent Cotton-Core Nonwovens Edward (Mac) McLean, Cotton, Inc.
Sustainability
New Biodegradable Copolyester for Fibers and Nonwovens W.A. Haile, Eastman Chemical Co.
Biodegradable Nonwovens—Natural and Polymer Fibers, Technology, Properties Dieter H. Mueller, Ph.D., BIK-University of Bremen
Sustainability Through 100% Resin Usage Bob Hawkins, Munchy Ltd.
Renewable Nonwoven Composites for a Sustainable Future Matthew W. Dunn, Philadelphia University
Biosoluble Glass Fiber For Use in Ultrafine Diameter Filtration Products Jon F. Bauer, Johns Manville Co.
Properties & Performances
Compressibility of Perpendicular-Laid Fabrics Containing Cotton D.V. Parikh, Ph.D., SCRC/USDA
Introduction of Plastic Net Scrim to Alter the Properties of a Hydroentangled Nonwoven Keith Misukanis, Conwed Plastics
Rapid Morphology (Property) Changes at Bond Edge in Thermal Point-bonded
Nonwovens Stephen Michielsen, Ph.D., Georgia Institute of Technology
Predication of Performance in Thermally Pointed Bonded Nonwovens H. S. Kim, Ph.D., NCRC
INDA Standard Test Methods Update and Comparison to EDANA, ISO & ASTM Michael Thomason, Ph.D., BBA Nonwovens
The Simultaneous Measurement of the Diameter and Length of Glass Microfiber Norman Lifshutz, Ph.D., Hollingsworth & Vose
Evaluation of Hand Characteristics of Nonwoven Fabrics Using Simple Methods S. S. Ramkumar, Ph.D., Texas Technical University
3D Shell Nonwovens: Properties and Characteristics Hugh Gong, Ph.D., UMIST
Binders & Additives
Incorporation of Antimicrobial Materials in Fabric Roy M. Broughton, Jr., Ph.D., Auburn University
Faster and Better - How Radio Frequency Drying Can Improve Both the Speed and
Quality of Your Nonwoven Process Ben Wilson, PSC, Inc.
Development of Halogen-Free Flame Retardant Melt Spinning Nonwovens Christine (Qin) Sun, Ph.D., TANDEC
Advances in Nonwoven Highloft Binders Represented By New Acrylic/Vinyl Chloride
Emulsion Polymers Martin A. Cohen, Ph.D., BF Goodrich Performance Materials
Calvin Woodings 12/Sept/01
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