The use of nonwovens technology in the industrial and technical sectors is expanding globally. Virtually every nonwovens system can be used for making nonwoven roll-- goods for some industrial or technical application, the optimum requirements of which cannot be met by any other form of fibrous structure. Derek Ward outlines the major systems, the associated machinery and the main suppliers.

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Most nonwovens systems differ from more traditional forms of fabric manufacture, such as weaving and knitting, in that they use a single, continuous operating line to transform fibre or polymer into a consolidated structure. Nevertheless, within the integrated line, the raw materials pass through several different processes, which differ according to the types of nonwovens being manufactured. If one stage within the line is halted for whatever reason or does not maintain required quality standards, the entire line is affected. Machine and equipment dependability is therefore critical.

There are many companies specializing in designing and engineering the machinery and equipment for the individual processes, and a number of automated control and monitoring systems are now available to facilitate the essential synchronized operation of the various components of a line. However, the increasing number of companies throughout the world planning to exploit growing demand for industrial and technical nonwovens has strengthened the appeal of the so-called "turnkey" concept-whereby a single machinery builder supplies a complete, integrated nonwovens manufacturing line. Of necessity, such lines usually consist of machinery constructed by the one builder, plus machinery sourced from others, the whole matched and balanced into a line that meets the precise needs of the individual manufacturer. This has encouraged a trend for builders to facilitate this turnkey concept through a number of formal or semi-formal consortiums.

As nonwovens manufacturers adopt a problem-solving approach to their customers' requirements, solutions increasingly involve use of more than one basic technology or composite material (for instance, spun bond/meltblown, spunbond/hydroentanglement, or staple fibre/ filament structures). It appears likely this trend will become stronger.

This article surveys some of the most recent developments in, and principal sources of, nonwovens machinery and applications for their products.

Fibre preparation machinery

The initial preparation stages in manufacturing fibre-based nonwovens involve operations similar to those associated with yarn spinning. However, the bale openers, mixers, fibre dosing and blending units, and tuft feeders are often linked in a bespoke configuration to meet the speed, output and uniformity levels required by specific nonwovens manufacturing lines.

Computer controlled and monitored fibre preparation installations capable of handling virtually any type of manmade or natural fibres are available to work in conjunction with nonwovens cards, air- laying units, needlelooms or thermal-bonding ovens. Virgin, blended or recycled fibre can be processed.

Preparatory machinery builders:

Bematic Srl, Italy

Rieter Perfojet is one of the key suppliers of complete installations for spunbonding. One of its latest innovations, the PERFObond 3000, was exhibited at ITMA Asia in October 2001-Technical Textiles International, September 2001.

NSC, above and facing page, has worked with Fleissner.

Cormatex Srl, Italy

Dell'Orco & Villani SAS, Italy

Fratelli Marzoli & C. SpA, Italy

H. Hergeth GmbH, Germany

HDB Houget Duesberg Bosson SA, Belgium*

Laroche SA, France

Masias Maquinaria SA, Spain

OMT Biella Sri, Italy

Octir Deutschland GmbH, Germany*

Octir Industriale SpA, Italy*

Pneumatic Conveyors (Huddersfield) Ltd, UK

Qingdao Textile Machinery Works, China**

Reisky & Schlese, Germany

Rolando Macchine SAS, Italy

Tecnomeccanica Biellese Srl, Italy

Temafa Textilmaschinenfabrik GmbH, Germany

Trutzschler GmbH & Co KG, Germany.

Octir Group

** China Textile Machinery (Group) Co, China.

Carding

A modern card employs an extremely sophisticated system of pinned rotating drums and strippers to take fibres from a feeding system, forming them into a uniform layer or batt. The fibres may be aligned in the machine, or longitudinal, (MD) direction, or in a random form. Today, cards designed specifically for use in nonwovens operations are used. The main design thrust over the past decade has been towards wider working widths and faster processing to match carding speeds to those of the other processes in the nonwovens line. Other requisites include more careful handling of expensive high-- performance fibres that are often difficult to process.

A variation on the traditional concept is the air-lay version. This uses a fibre separation stage then transports the fibres on a stream of air before laying them down as a random web. The system's use was formerly confined to processing relatively short fibres, but modern air-lay systems have to some extent overcome this limitation. Features of carding and air-lay systems may be combined in one unit. Processing speed limitations are also being overcome and 20-250 g.m^sup -2^ air-laid webs can now be made at up to 150 m a minute.

Carding machinery builders:

Befama SA, Poland

Bematic Srl, Italy

Bonino Carding Machines SAS, Italy

Cormatex Srl, Italy

Fehrer AG, Austria

F.O.R. Ing. Graziano, Italy

Octir Industriali SpA, Italy

Spinnbau GmbH, Germany*

Wm Tatham Ltd, UK

Thibeau, France**

Zhengzhou Textile Machinery Plant, China***.

Dilo Systems Group

NSC Nonwovens Group (see also, outside back cover)

*** China Textile Machinery (Group) Co Ltd.

Crosslappers

Crosslapping is a method of building up the thickness of a fibre web. The web is fed from the delivery station of a card and deposited in layers across the width of the moving belt of the crosslapping unit. The crosslapper is normally positioned between the carding section and a pre-needling unit or needleloom or other means of web consolidation. Modern cross-lappers employ various high technology methods to achieve a uniform profile across the full width of the layered web, circumventing irregularities. Uniformity is crucial to the quality of the finished nonwoven.

Crosslapper builders

Asselin, France*

Autefa Maschinenfabrik GmbH, Germany**

Automatex Nonwoven Srl, Italy

Befama SA, Poland

Global Nonwovens, China

Qingdao Textile Machinery Works, China***

Reisky & Schlese, Germany

Tec Tex (2N), Italy

Taiwan jie Sheng Enterprise, Taiwan

Wrn Tatham Ltd, UK.

NSC Nonwovens Group (see also, outside back cover)

Dilo Systems Group

*** China Textile Machinery (Group) Co.

Needlelooms

Needlepunching represents one of the longest established systems for consolidating a web of fibre, and is still the most widely used mechanical system. The earliest needlelooms became available in the 1870s. Horse blankets were one of the first targeted markets.

The basic concept uses barbed needles mounted on a vertically reciprocating beam to penetrate the fibre web, entangling the individual fibres and so consolidating the web.

For more than a century, this concept has been constantly developed, refined and automated-to add speed, versatility and increased efficiency. Modern needlelooms, for pre-- needling or finish needling, are highly sophisticated and automated. Recent innovations include curved bedplates to achieve more intensive needling effect and an elliptical needlebeam movement that permits high-speed (3000 strokes a minute) operation without causing the longitudinal draft that could affect the quality of the nonwoven. Needlelooms produce an extremely wide range of industrial products, including insulation materials, filtration media, synthetic leather substrates, packaging, industrial floorcoverings, automotive trim, geotextiles and civil engineering materials, agricultural and horticultural fabrics, footwear materials, and papermakers felts in widths up to 15 m. Needlelooms are also often incorporated in spunbonding lines to consolidate heavier weight constructions.

Needleloom builders:

Asselin, France*

Asselin, and Thibeau, are both parts of the NSC Nonwovens Group (see also, facing page and outside back cover).

Automatex Nonwoven Sri, Italy

Heuer & Sohn Spezialmaschinenbau, Germany

Oskar Dilo Maschinenfabrik KG, Germany**

Fehrer AG, Austria

* Shoou Shyng Machinery Co Ltd, Taiwan

* Tec Tex (2N), Italy.

* NSC Nonwovens Group (see also, outside back cover)

* Dilo System Group.

Many other long-established methods, such as latex bonding (by which latex was applied to the fibre web by spraying, dipping, printing or foaming), have often been superseded by more modern methods made possible by advanced fibre, polymer and new mechanical technologies that have also enabled nonwovens to enter fresh markets.

Thermal-bonding equipment

Thermal-bonding takes advantage of the thermoplastic characteristics of most synthetic fibres. Heat is used to melt, and fuse together where they touch, the surfaces of similar fibres within a web. The proportion of these bonding fibres within the web can be varied to achieve the desired levels of structural strength, drape and overall performance. Synthetic fibres of relatively low melting point, such as polypropylene or polyethy\lene, are widely used for this purpose. Sheath/core bicomponent fibres, with a lower melting point sheath, are also popular: the sheath provides the fusing point while the core preserves the integrity of the nonwoven. A major advantage of thermal-bonding is that it creates a nonwoven free of resins or chemical bonding agents. Two systems of thermal- bonding are commonly used: calender bonding and through-air thermal- bonding.

In calender bonding, the web passes between nips formed by two or three rolls heated by oil, gas or electricity systems. Various combinations of smooth and engraved rolls are available. Engraved rolls can produce a surface pattern on the nonwoven or modify its performance characteristics. Some of the latest calender installations can employ temperatures of around 300 deg C. Tolerances of +/- 1 deg C preserve structural uniformity of the nonwoven across widths up to 12 m. Output speeds vary according to the nonwoven structure being processed, but as high as 800 rn a minute is claimed. A major advantage of calender bonding is its versatility: installations are compact and product changes can be made relatively easily. Through-air thermal-bonding fuses the bonding fibres in a web as it is taken on a conveyor through an oven or passed around one or more large perforated drums. Hot air is blown or drawn by a vacuum through the web. In multi-- drum lines, the airflow through the web can be alternated. The compact configuration of a vertical drum installation can offer a significant space-saving advantage over horizontal configuration ovens. Through-air drum installations are used extensively in consolidating spunbonds and spunbond composite structures, and can also combine drying and thermal-bonding simultaneously.

At ITMA 1999, LaRoche featured the highly innovative Hermann air- laying process that can be used to make semi-cured, resin- impregnated felts, which can then be moulded.

A third system, which involves adding a thermal bonding powder to the fibre then passing the web through an oven, is much less widely used.

Typical industrial products include lightweight coverstock (for hygiene, medicare and surgical use), interlinings, industrial wipes, filtration media, footwear components, wallcoverings, geotextiles, roofing membranes and civil engineering fabrics.

Thermal-bonding equipment builders:

* Amdes, France

* Bombi Meccanica Srl, Italy

* Brickner Trockentechnik GmbH & Co KG, Germany

* Casaretto GmbH, Germany

* Comerio Ercole SpA, Italy

* Fleissner GmbH & Co, Germany

* Gualchierani, Italy

* Eduard Kosters Maschinenfabrik GmbH & Co KG, Germany

* Lemaire & Cie, France a Monforts GmbH & Co, Germany

* Phoenix Dryers & Engineering (Blackburn), UK

* Santex Nonwoven, Switzerland

* Sicam Srl, Italy

Views (above and below) of LaRoche's Napco 3D Web Linke (see also Technical Textiles International, October 2001, page 23;

* Valmet Honeycomb, France

* Web Processing, UK.

Spunbonding/meltblown

Spunbonding differs from most other major nonwovens systems in that it is primarily a polymer-based technology. A sheet of thermoplastic filaments is extruded, directly from polymer chips, from a line of spinnerets mounted on a beam. The filaments fall on a conveyor as a web, which is usually consolidated into nonwoven rollgoods by thermal-- bonding, needlepunching or, in some cases, chemical means. The first spunbonds, introduced commercially in the late 1960s, were initially considered to have limited potential as far as applications were concerned. They were originally promoted as being suitable for use in geotextiles and carpet substrates. Over the intervening decades the technology has become extremely sophisticated and the number of applications is multiplying.

The potential for further development has been considerably enhanced by the introduction of multi-beam lines and melt-blown technology. The latter is another polymerbased system in which drops of melted polymer are metered into airstreams where they are elongated into microfibres that are then collected as a voluminous, yet extremely lightweight, material.

In many modern installations spunbonding and meltblowing can be carried out simultaneously to produce multi-layer composites on the same line. The spunbond component may consist of filaments of different denier or bicomponent filaments. Recent technical developments include the use of hydroentanglement (see below) as the bonding system. Spunbonds and spunbond composite constructions, such as spunbond-meltblown-spunbond (SMS) - as well as various permutations such as SSS, SMMS and SSMMS, in addition to others involving film layers - are widely used for a variety of industrial and technical applications including geosynthetics and civil engineering fabrics, agricultural and horticultural materials, air and liquid filtration media, medical and surgical fabrics, various types of specialist industrial wipes, environmental protection materials, workwear and protective apparel, battery separators, automotive components, floppy disk liners, interlinings, packaging, oil sorbents, acoustic and other types of insulation, roofing and moulding substrates.

Suppliers of complete installations:

Accurate Products, USA

Ason Neumag (Saurer Group), Germany

Fare, Italy

Hill Inc, USA

Meccaniche Moderne SpA, Italy

Nonwovens Technology Development Centre, China

Nordson Fiber Systems, USA

Noyvallesina Engineering SpA, Italy

NWT - Non Wovens Technology, Italy

Plantex SpA, Italy

Rieter Perfojet, France

Reifenhauser GmbH & Co, Germany

STP Impianti SpA, Italy.

Hydroentanglement (spunlace)

Fehrer's innovative H I Series of needlelooms uses curved bed- plates and stripper plates.

Both pre-needling and finish needling versions are available.

Hydroentangled or spunlace nonwovens are formed basically by using powerful water jets to entangle and so consolidate the fibres of a web. In the process, the water jets impinge upon the web as it passes around a drum or drums. Plain or patterned nonwovens can be achieved.

Early limitations on width and disadvantages associated with power requirement and water use have been overcome. Recently, the same technique has been suitably modified for consolidating the filament sheet extruded in a spunbonding process.

The resultant spunbond combines the drape of a spunlace construction with the strength of a filament structure.

Hydroentangled nonwovens combine softness and drape performance, and are basically free of chemicals. However, anti-bacterial, anti- static, anti-flammable and other performance characteristics can be incorporated. Webs of blended fibre, man-made and natural, can be used to achieve specified performance. Currently, a major market is that for specialist wet and dry wipes. Other applications include healthcare and medicare products, synthetic leather and other coating substrates.

Installation suppliers:

Fleissner GmbH & Co, Germany

Rieter Perfojet, France

Taiwan Spunlace (Group) Co Ltd, Taiwan.

Vertical lapping systems

At Index02, Fleissner emphasized the versatility of its Aquajet hydroentanglement machinery pointing out that further versions of the basic technology ore being introduced. For instance, the German company has cooperated with the NSC Nonwovens Group to develop integrated lines see also, page 18).

As well as NSC, see also page 17 and 23, Fleissner has cooperated with other companies such as Danish firm

Dan-Webforming, whose air-lay line is shown here combined with the German partners Aquajet hydroentanglement machinery.

Two innovatory systems for manufacturing bulky nonwovens have recently been introduced and the first installations reported. Both systems employ vertical lapping systems by which a voluminous web of carded fibre is fed vertically downwards to a conveyor to be formed by a blade or toothed discs into a corrugated structure. The structure is then passed through an oven to be thermal-bonded.

Fabrics for automotive uses, such as interior trim, general insulation and headliners are suggested. Other technical applications include thermal and acoustic insulation, civil engineering and building materials, footwear cushioning and moulded insoles, upholstery fabrics, and mattress pads based on different combinations of natural and man-made fibres. In addition, sleeping bags, isolation mats, air/liquid filtration media, and high- performance apparel and sportswear are cited as potential areas of use.

System suppliers:

Santex Nonwoven, Switzerland

Struto (Liberec Technical University), Czech Republic.