Significant hydroentanglement energy savings arise from
alternating single nozzles - compared with the traditional approach of using
multiple nozzles on one side followed by multiple nozzles on the other.
Production Technology
A typical needlefelt production line would have the
usual fibre opening and blending equipment feeding cards or garnets. A
cross-lapper would be used to raise the basis weight, achieve the target width
and orient the fibres mainly in the cross direction. A pre-needler reduces the
bulk of the cross-lapped web and gives it sufficient integrity for finish
needling. This varies in type and intensity according to the density, strength
and structuring required.
Conventionally, needlefelts have two similar flat
surfaces obtained by punching from both sides, sequentially or simultaneously.
Needle densities are now typically 3,000 to 5,000 per metre of board length, and
boards can punch the web 3000 times per minute. Needles are available in
numerous shapes and sizes, triangular section with barbs cut into the apex being
common. Structure is obtained by needling with barbless needles with a forked
tip, the web being supported on grids or brushes that allow a pattern to develop
as the needles penetrate the lower surface.
[Bill Neely, Sales Rep. Groz-Beckert, 803 48 4769]
Improved Carding…
4.5 metre wide nonwoven cards are now running routinely
at speeds in the 300 to 400 m/min range with PP fibres of 2.3 denier and less to
make webs of 10-35 gsm. A 5 metre card is also operating, but no data on it's
performance can be released yet. Reviewing how such progress has arisen,
Jean-Noel Cozon, VP Schlumberger (USA) Inc. listed numerous design
improvements , many involving gaining more control of
the air currents in the cards and around the conveyors
taking webs from the doffers. The Injection principle pioneered by FOR
“harnesses laminar flow around the main cylinder with a specially shaped
plate-profile to create a Venturi which helps to strip the web off a worker”.
This, in conjunction with an air-curtain eliminates stripper rolls and allows
simplification of design. Internal suction systems allow Spinnbau and other's
sealed cards to operate under a partial vacuum reducing dust, keeping fibre from
the edges of the rollers and enabling the delivery of very clean webs. Thibeau's
patented ISM system uses different widths of stripper, worker and cylinder
linked to such air control to allow near-perfect edges.
Doffing onto perforated conveyors with suction boxes
controlling the web; the use of suction rolls at web transfer points, and the
use of suction aprons based on short-fibre air-lay technology, all combine to
allow webs to be fed from card to bonding at 400 m/min without disruption. With
needling in mind, total integration of card and crossfolder to produce flat,
stress free batts which no longer need profiling is under development.
[Jean-Noel Cozon, VP Schlumberger (USA) Inc. 803 548
7233 or email jean-noel.cozon@ncusa.com ]
Faster Needloom…
One of the fundamental problems with modern needlefelt
quality arises from drafting; the web being stopped every time the needles
penetrate while web-feed and take-off rolls run continuously. The take-off rolls
are thus pulling against a stationary web for about 40% of the time so the
advance per stroke and hence machine speed is limited by how much distortion the
web can take: in practise this is rarely more than a 30mm per stroke.
In response to a demand from the spunlaid producers for
a system that would run at 150 m/minute, Dilo have developed Hyperpunch
technology , which uses an elliptical needle path capable of advancing the web
by up to 50mm for each revolution of a 3000 rpm machine. Terry Purdy of Dilo,
Charlotte described a series of trials on a 3.5 metre wide Hyperpunch system at
their Technical Centre in Eberberg , Germany . The data gathered demonstrated
that the new system removed the drafting associated with needle penetration
completely, allowing heavier, wider webs to emerge at higher speed, unspoilt by
needle marks and having reduced variability in profile.
Benefits were most pronounced when needling with 4
boards, the needles assisting web passage from both sides simultaneously. Such
finishing looms appear to be capable of taking webs straight from the
crossfolder, allowing the pre-needler to be dispensed with. In response to
questions Terry said that elliptical needling technology improved edge-quality
so much it allowed paper machine felt producers, who generally trim a metre off
each edge of loomstate fabric, to use narrower machines.
[Terry Purdy, Technical Director, Dilo Inc., 704 357
3456, or email
Drterrypurdy@aol.com
See also USP 5,732,453 March 1998]
Faster Crosslaying…
Rodney Kershaw of William Tatham Ltd., (the inventors of
the crosslapper in 1929) 9described a fundamental design change allowing the
elimination of traverse drives and hence the elimination of apron stress caused
by small speed differences between conveyor motors and traverse motors. The new
‘U' format conveyor systems are mirror-imaged top to bottom to provide a
balanced stress-free motion. These simplified conveyor paths eliminate
wrap-backs but most important, the reduced inertia of the traverses and the
absence of reversing motors allows higher speeds cross-lapping.
Maintenance schedules and downtime are also reduced. The
Quin Servonet integrated control system features reduced wiring, provides
accurate control of all AC Servo motors and includes extensive real-time
diagnostics.
In response to questions, there is one machine operating
in California and another due for US delivery in May. There are four operating
in the UK and two more on order. Outer conveyors can be changed in 2 hours and
inner conveyors in 4 hours.
[Rodney Kershaw, Sales Director, +44 1706 345888]
Automatic Needle Changing…
The VSC 1000 is a fully automatic needle loading and
changing system from Officina Meccanica Montenero . It laser-scans an empty
board memorising and charting each hole position no matter how they are
arranged. It can take a bucket full of needles, sort and mount them in a
chain-magazine from which they are inserted in the board with the orientation
desired. When, after use, an operative reinserts the board, the VSC 1000 recalls
the needle position file, extracts needles as requested, records the positions
of any breakages and stores the data on needle-life.
The needle-change options include Replace All, Replace
only Broken, Replace only in Zone Specified, Replace only those with a Specified
Rotation, and Remove All. It works with boards up to 85” x 16” with thicknesses
between 0.6" and 1.0”. Needles can be up to 3.5” long and 1.83mm diameter. The
chain-magazine loader can sort and load 1200 needles per hour. The Replace All
option works at 1000 needles per hour, and runs for 5 hours on a single
chain-magazine.
In response to questions, Paulo Finocci said it cost a
little under $200,000, the first machine being installed near Florence in Italy
in May, and the second in September this year. Would it detect the occasional
wrong needle when loading the chain-magazine? Yes, but only based on needle
length.
[Paulo Finocci (President) +39 0574 650743, email
montenero@ui.prato.it]
Needle Forces…
Measuring the force experienced by needles at different
positions across a needleboard while varying basis weight, needling density and
fibre parameters generated some unexpected results. With transducers on needles
in a line along the machine direction in the centre of the board, forces were
observed to rise to a maximum near the centre and fell as the web became more
consolidated. As needling density or fibre length was increased, the position of
maximum force moved towards the feed side, but changes of basis weight did not
affect it. The peak force experienced by needles increased with increasing
length, needling density and basis weight. Asked about the practical
implications of his work, Prof Abdelfattah Seyam of NCSU thought that if similar
transducers were fitted to needles in production, they would: a) provide a
valuable additional measure of fabric uniformity, b) would enable variations in
fibre finish to be detected, and, if sufficient were used would c) be sensitive
enough to pick up the increased forces resulting from needles breaking in the
neighbourhood of the transducer.
[Prof Abdelfattah Seyam, 919 515 6583 or email
aseyam@tx.ncsu.edu]
Hydroentanglement v. Needling…
The economics of hydroentanglement according to Perfojet
were used by Daniel Feroe, their North American Sales Manager, to draw some
interesting comparisons with needlepunching. Counter-intuitively, the costs of
electricity, gas (for drying), water, and water filtration materials amounted to
only 2.7% of the $2.29/kg total cost of the hydroentangled fabric in question.
He made the point that while energy costs per hour were much higher than
needling, the output per hour of HE was much greater. While the two processes
targeted different market sectors at present, he saw HE being capable of moving
into needling territory in automotive, horticulture, roofing, geotextiles,
coating bases and cable construction. Within automotive needlepunched fabrics
would remain pre-eminent in lower door trim and composites, but would be
vulnerable in package trays, trunk liners and rear hatch covers and headliners.
He put the 1999 world capacity for HE fabrics at 230,000
tonnes and foresaw a continuation of the exponential growth as fabrics like
PGI's “Miratec” and Freudenberg's “Evolon” (HE'd spunlaid splittable polyester)
penetrated further into conventional textiles. Asked about lines using both HE
and pre- needling, he knew of none. HE headliners were absent from the US market
but under development in Asia and Europe . The coarsest fibres used in HE were
currently 3 denier, largely because, leather substitutes aside, the technology
was still targeting lighter weight disposables.
[Daniel Feroe, N. American Sales Manager 336 668
9581 or email danicbt@aol.com ]
Improved Hydroentanglement…
Don Gillespie, Vice President of Fleissner Inc. looked
to the future of hydroentanglement line development. They would be showing a 5
metre wide unit at ACHEMA in Frankfurt between May 20 th and 27 th this year and
while 600 bar and 600 m/min figures have been associated with this next
generation of machines, Mr Gillespie indicated that 200 bar and 250-300m/min
were more typical. In fact the highest working pressure known to be installed on
a commercial line was 350 bar. 600 m/min would be needed to allow HE to be used
on spunbond lines.
New filtration systems, better perforation techniques,
better jets, a new manifold design and reduced energy consumption were all under
development. Part of the improved energy consumption would arise from the
discovery that the two-sided entanglement needed for heavier products is best
done with alternating nozzles (ABABABAB) rather than the AAAABBBB approach which
is now standard. A 600 gsm felt has been made from only 5 high-pressure
treatments “up to 600 bar” using this technique. The ability of the high
pressures to split splittable fibres, including lyocell, was illustrated.
(although in the case of lyocell, the SEM shown was of fibres refined by Acordis
in a beater.
[Don Gillespie, Vice President, 704 394
3376]
Fibres
The use of sheath-core bicomponents in needling to
achieve mouldability especially for automotive applications is well known.
However a new low-melt sheath on a bicomponent fibre from Kosa gave stronger
fabrics at 143 o C than standard bico at 166 o C, allowing energy savings or
higher line speeds. Another new bico, this time with a high-melt sheath allowed
automotive headliner specifications to be met.
Lana Irish, Kosa's Staple Market Manager went on to
indicate how exotic polymers could be “cored” with cheaper carriers to deliver
their attributes at lower cost. When it required protection from the rigours of
carding and needling, the premium component would be in the core.
The high-melting polyethylene naphthalate (PEN) was a
possible sheath for hot filtration, and the polytrimethylene terephthalate (PTT)
polymer with it's improved abrasion resistance, dye uptake and elastic recovery
would add these features to an ability to give self-bulking bicomponents.
Asked about the slow uptake of the islands-in-a-sea
types in the USA , the problem was the lack of finishing machines capable of
extracting the “sea”. With regard to the flame retardant bicomponents, Kosa were
making the core FR to allow the sheath to be dyed normally.
[Lana Irish, 704 948 3705 or email lana.irish@kosa.com ]
Trends in Staple Fibres…
After explaining the main features of two-step, one-step
(compact), and in-line high speed staple fibre spinning processes, John
Hagewood, Business Development Manager of Hills Inc., examined trends in the
staple fibre industry.
Polypropylene staple is increasingly made by what used
to be the fibre industry's customers. Numerous major users have installed their
own compact spinning machines, and others have switched to spunbond, including
bico and ultra fine denier fabric production.
The reducing staple market is driving the fibre
producers to specialise on the harder-to-make fibres and polymers. Hills Inc.
were now increasingly involved with poly lactic acid (PLA), poly trimethylene
terephthalate (PTT), polybutylene terephthalate (PBT) and even poly vinyl
alcohol (PVOH).
Asked about poly-lactic acid he said it was an excellent
fibre to spin provided it's properly dried and preconditioned. Asked about it's
performance in ironing, he said his knitted PLA golf shirt (probably from
Kanebo) did not need ironing.
Cargill-Dow Polymers LLC were said to be concentrating
on apparel and yoghurt pot outlets for the polymer. The yoghurt pots used a
lower molecular weight and hydrolysed in hot water to become fully
biodegradable.
[John Hagewood, Business Development Manager, 407
724 2370 x216 or email Jhagewood@hillsinc.net ]
Kenaf composites?
The increasing automotive industry interest in
biodegradable composites with jute and hemp as reinforcements has encouraged the
USDA's Southern Regional Research Centre to examine the potential of that other
bast fibre, kenaf. The problem with kenaf, according to SRRC's D.V.Parikh is
that it is uncardable when normally extracted by natural retting. His chemical
retting process, in essence a caustic extraction at the boil in a stirred kier,
yielded a fibre which he thought could be carded and needled for testing.
After the 5 hour hot-wash/caustic
boil/hot-wash/neutralising wash/finish sequence in the keir, weight losses of
between 30 and 40% were recorded as the lignin etc. was extracted. However a
further 25 to 30% of the fibre was lost, presumably as dust in carding, even
when optimally lubricated with soap finish.
Asked about the fibre denier, it had not been measured
but was thought to be around 20. The fibre extension had been reduced to between
1 and 2% by the chemical treatment and this could account for the carding
losses.
The needled nonwovens properties presented were based on
a 7.5 oz/sq.yd 80/20 kenaf/cotton blend and a 20 oz/sq.yd composite of 35%
kenaf, 35% recycled polyester and 30% PP. A similar blend had been air-laid and
then needled to a spunbond PET scrim.
[D.V. Parikh, 504 286 4406 or email parikh@nola.srrc.usda.gov ]
Needled Superabsorbents
In addition to being brittle, superabsorbent fibres tend
to be coarse, have no crimp, and get sticky if exposed to elevated humidity for
any length of time. Carding them therefore requires special care: too low a
humidity and they break up, too high a humidity and they stick to the wire.
Nevertheless they are being carded, needled and
converted into a variety of new products outside the obvious hygiene market.
Ed Homonoff (Consultant) described several:
- Protective garments with a central layer of
SAP-containing felt between a conductive waterproof liner and a breathable shell
have been patented for use by fire-fighters. The garment is pre-wetted before
exposure to flames.
- Chemical spillages can be controlled using felts
containing SAF, and a similar product has been patented for controlling body
fluid spillages in autopsies, surgical procedures and transport.
- SAF-containing pads are used in fish and meat packs to
immobilise fluid without contaminating the produce. Similar pads can be
prewetted and used to wrap fish before freezing. This form of packing weighs
less than the ice normally used, and there is no water leakage on thawing.
- The use of a SAF-containing filter in a respirator
allows absorbtion of exhaled moisture and re-humidification of the next
inhalation.
- SAF-containing fuel filters can detect moisture in fuel
and if required, shut off the fuel flow from faulty sources.
[Ed Homonoff (Consultant), 860 774 5949 or email Edward_ch@snet.net . See also USP's
5,885,912; 5,577,494 and 4,242,206 and WO 91/017766A]
Market Information
Excepting big names like Foss, Amoco, Lydall and
Phillips, most of the 270 needlefelt producers in the USA are
small family concerns. Lines could be obtained for between $200,000 (pre-owned)
and $3,000,000, and while the latest equipment was necessary to compete in the
two biggest and most competitive markets, automotive and geotextiles, some
home-furnishings, industrial and marine fabrics could be made successfully on
older machines.
In Europe , the 370 companies using
needlelooms have a product range at least as diverse as the USA , but make a
greater proportion of technical felts such as the synthetic leathers.
Japan , with over 130 producers, many
driven by automotive industry quality requirements, probably make the world's
best products. They typically use finer denier PET rather than PP, have their
own R&D departments, and were of course the originators of the microfibre
felts first developed as artificial suede.
Korea and Taiwan are now the world's
largest producers of impregnated and coated needlefelts for “leather” uses
thanks to the concentration of sports shoe producers such as Nike and Reebok in
the region.
China , is a large producer of
relatively non-critical products for home furnishings, with some 90-150
needlers.
Latin America has 60 needlepunchers,
the majority being small family-owned firms, but with US educated CEO's.
Blankets, Paddings, Automotive, Carpets and Filtration are typically targeted
markets, but the fact that 40% of Argentina 's needlefelts went into Wiping, and
80% of Brazils carpets were made by needlepunching stood out.
Sisal, jute, tampico , tequila and hair were the main
fibres used in automotive and furnishings fabrics, but blankets were still
mainly made from shoddy. Mexican production for automotive use had tripled in
the last 15 years, 60% being used locally.
Geotextile production is relatively new but growing
fast. Unlike Brazil , the rest of Latin America and even Europe, the USA used
negligible quantities of needlepunch in carpets.
[John Foster, VP - Foster Needle Co., Inc, 920 682
6314]
Far Eastern Progress…
The "Emerging Five", defined as China , Indonesia ,
Thailand , Malaysia and the Philippines , produced 216,000 tonnes of roll-goods
worth $810 million in 1999. This was 9% of global roll-goods use, up from 4% a
decade ago, and expected to grow to 12.1% by 2004.
Mature western markets were using about 2 kgs/head of
nonwovens per year (1.4 kg disposables and 0.6 durables) while the emerging five
were consuming less than 0.3kg.
Nonwovens Production in the Five was:• 38%
dry-lay latex or thermal bonded,
• 28% spun-bond (25 PP lines and 4 PET
lines in China but only one other in Indonesia),
• 27% needlepunched (300
lines, two-thirds being in China ),
• the remaining 7% being mainly
spun-laced (10 lines in China ) and meltblown.
The absence of air-laid in 1999 was notable, the gap now
being filled by the 20,000 tonne BBA plant recently announced. Where were the
needled products made by the Five mainly used? In geotextiles, coating bases,
and shoe materials. Shoddy and the coarser natural fibres were used for bedding,
matting and blankets.
[Ian Butler, Consultant, 905 885 8815]
A New Market?
Fire ants, despite pesticides and biological controls,
have spread from their original foothold in Mobile Alabama to become a nuisance
over most southern states. A novel suggestion for their control involves the use
of needlepunched geotextiles. Howard Thomas of Auburn University has
experimented with various geotextiles and discovered that while the ants easily
eat their way through dense flash-spun olefin house-wrap, they are stopped by
looser 3.8 oz/sq.yd felt made from 1.5 denier polyester fibres needled to 550
ppi.
Because the ants cannot survive cold or elevated
temperatures he recommends laying the felt about a foot below ground to prevent
ants forming their colonies at the 3ft to 12 ft depths where the temperature is
constant enough to permit their survival.
He calculates that if 10% of all the new housing starts
in the fire ant's US territory used a felt layer under the yard, these yards
would remain ant-free and a new market consuming 112mm sq.yds per month of
nonwoven would be created. The same technique appears to control termites also,
yielding another 15 mm sq.yds/month if 10% of house foundations used the method.
Similar problems exist in Australia , Brazil and Mexico . Dr Thomas is now
looking for support for field trials.
[334 844 5461 or email hthomas@eng.auburn.edu ]
Trade Statistics…
US government trade statistics reveal imports and
exports of needlepunched fabrics. Two of the Harmonised Tariff Schedules,
HTS5602 and HTS5603, are worth looking at. HTS5602 (10% duty applicable) covers
all felts: traditional or needled, loomstate or coated or impregnated, whether
made from animal fibres or manufactured fibres. This category also includes
stitchbonded materials.
HTS5603 is the nonwovens roll-goods tariff, not strictly
relevant to needlepunched, but having recently become duty-free, its illegal use
for needlefelts could be distorting the import statistics.
Of the 20,500 tonnes of felts exported by the US in 1999
(up from 11,400 tonnes in 1994) Canada received 8,400 tonnes, Mexico 3,700
tonnes and Korea 2,000 tonnes. Canada was also the main exporter of felt to the
US , accounting for 6,700 tonnes of the total 1999 imports of 11,500 tonnes, the
UK being second in importance with 1,500 tonnes.
The written text includes a complete print out of HTS
5602 statistics for 1994-99, for every country and to the nearest kilogram. For
the net enthusiast, the websites to watch were:
[Peter Mayberry, Director of Government Affairs,
INDA, 703 847 6747 or email pmayberry@inda.org ]
Miscellaneous
John Mycock of ETS Virginia described a
baghouse filter fabric verification test that would allow the Enviromental
Protection Agency to streamline the process of granting permission for fabric
use by the US air-pollution control industry. Tests on the ETS test rig cost
$9500 per fabric, but the EPA will pay 90% of this. Fabrics which pass get a
verification certificate signed by the EPA for use in promotional literature.
[John Mycock, Executive VP, ETS, 540 265 0004 ext.2]
Donald Hindman, the Director of Engineering at
Thantex Specialties Inc illustrated how the omnipresent, economical,
but underused Microsoft Access could be used to record, analyse and report a
multitude of statistics arising from a needlepunch line.
[828 687 0940 or email DonHind@juno.com ]
Mark Wolpers of Temafa reviewed their
machines for opening and blending staple fibre.
[+49 22 02 10 01 0]
Ed Vaughn of Clemson University
provided an overview of fibre types and their properties (illustrated
with information from the
www.afma.org and
Fibersource web sites) followed by the basics of web preparation.
[Prof. Ed Vaughn, 864 656 5965]
Robert Parsons of RAP Associates gave
an overview of fabric finishing techniques.
[508 778 5226, or email rap1935@aol.com]
The INDA website (
www.inda.org ) bibliography now has abstracts of
the papers given at the last 10 years of conferences in keyword-searchable form.
Full copies of the papers can be obtained for $20. They are also setting up an
online resource database , effectively a list of suppliers and
their products.
CRW 1/5/00
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