- Data on the new 5 metre cards is still classified, but 4.5 metre versions are running routinely at 375-400 m/min on fine denier polypropylene
- A redesign of the cross-lapper has led to a less mechanically-complex, high speed, high performance design.
- The development of needlelooms with elliptical needle paths has raised the theoretical speed limit to 150m/min while reducing drafting and improving nonwoven surface appearance. These machines may be able to compete with hydroentanglement in the 70-100 gsm range.
- A fully automatic needle changer has been developed.
- In a comparison between hydroentanglement and needlepunching, the extra costs of the wet process were put at only 2.7% of the total HE fabric costs.
- 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 TechnologyA 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 ofthe 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 email@example.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 firstname.lastname@example.org]
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 email@example.com]
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 firstname.lastname@example.org ]
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]
FibresThe 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 email@example.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 firstname.lastname@example.org ]
Needled SuperabsorbentsIn 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:
[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]
- 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.
Market InformationExcepting 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 email@example.com ]
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:www.usitc.gov (source of the data used in the paper)
and www.customs.gov .[Peter Mayberry, Director of Government Affairs, INDA, 703 847 6747 or email firstname.lastname@example.org ]
MiscellaneousJohn 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 email@example.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