Airlaid Web Formation Techniques for Nonwovens

Last Updated on 28/05/2021

Airlaid Web Formation Techniques for Nonwovens

Ramandeep Singh
B.Tech, Dept. of Textile Engineering
Giani Zail Singh Punjab Technical University Campus,
Bathinda, Punjab, India


Airlaid and airlaid web formation:
Airlaid is a web formation process. Airlaying or airforming is a method of forming a web by mixing fibers with air to form a uniform air-fiber mixture that is then deposited on a moving air-permeable belt or wire. The process for making airlaid nonwovens involves three primary steps: fiber defibration, web formation and web bonding.

There are two main forming technologies used to produce airlaid webs. With the first, the fluff pulp and staple fibers are sifted through a coarse screen and deposited with the aid of a vacuum onto a forming wire below it. The second system employs formers – the fibers pass through a series of holes or slots in a large cylinder that spans the width of the forming wire.

There are three primary bonding technologies: latex, thermal and hydrogen bonding. The term multi-bonding is used when more then one of the above technologies are used in combination, generally latex and thermal bonding.

Airlaid wipes provide an efficient carrier for the effective and economical application of a variety of active ingredients. Over 40% of the webs are converted to wipes. Major airlaid nonwoven producers include Buckeye Technologies, Concert Industries, Georgia-Pacific Nonwovens, Rexcell (Duni), McAirlaid, Oji and BBA.

Principle of web formation in a simple airlaying process:

Principle of web formation in a simple air laying process

Raw material

  • Natural or man-made textile fiber (cut length >25 mm)
  • Short cut fibers (generally <25 mm)
  • Wood pulp (1.5–6 mm)

web formation process

Airlaid fabric compared with carding technology has these features:

  1. The fibers are oriented randomly on the fabric surface – isotropic structure.
  2. Voluminious webs can be produced.
  3. The range of the area weight is wider (15 – 250 g/m2) but the mass uniformity of light air laid (up to 30 g/m2) is bad.
  4. Wide variety of processable fibers

Airlaid – production problems

  • Low level of opening fiber material by licker-in roller. Thus is suitable to use pre-opened fibers or combine air-laid with card machine – Random card machine.
  • Variable structures of web in width of layer due to irregular air flow close to walls of duct. This problem requires high quality design of duct.
  • Possible entangling of fibers in air stream. This problem can be reduced by increasing the ratio air/fibers which nevertheless means decrease in performance and increase of energy consumption due to high volume of flowing air.

The relation between air flow and performance of device shows the importance of fiber length and fiber diameter. QA is air flow, K is device constant, P is performance of device (kg/hour), L is length of fiber staple (m) and D is fiber fineness (dtex).

QA = K.P.L2/D

Thus is suitable to use short fibers for this technology.

Random cards – combination of air laid and carding technology
A major objective of this combination is isotropic textile fabric (random orientation of fibers) with good mass uniformity of light fabrics and with high production speed.

  • The first part – card machine opens perfectly fibrous material so single fibers are as a output.
  • The second part – airlaid system uses the centrifugal force to strip the fibers off a roller and put them down on an air controlled scrim belt.

Main variations of random cards

Main variations of random cards

Main variations of random cards I
Airlaid function of random card:

1) Random roller between main cylinder and doffer, which rotate in the opposite direction of the main cylinder.

Airlaid function of random card

Main variations of random cards II.

2) Centrifugal force of mean cylinder strips the fibers off.

Random card Fehrer K12
Airlaid and random cards: used fibers
Synthetic fibers, viscose, cotton and blends there of; natural fibers such as flax, hemp, sisal fiber etc.; Reclaimed textile waste and shoddy, cellulose pulp 1.7 – 2000dtex. Max. 120 mm staple length

Feeding system of rando webber

Feeding System of Rando Webber

Rando-webber systems with perforated screen

Rando-Webber Systems With Perforated Screen

Rando webber systems with cylindrical condensers

Rando Webber Systems With Cylindrical Condensers


  • Relatively narrow widths up to about two metres
  • Webs of 10– 3000 g/m2
  • Virgin or recycled fibers
  • Filtration, home furnishings, automotive fabrics, insulation and some medical specialties.

Random card K12 of Dr. E. Fehrer

Random Card K12

High-production random card K21 of Dr. E. Fehrer

High-Production Random Card

  • K12 is more particularly suited to coarse fibers (10–110 dtex), Basic weight range 20– 2000 g/m2
  • K21 is more particularly suited to synthetic and viscose rayon fibers of (1.7–3.3 dtex), Basic weight range 10–100 g/m2

Comparison of Card K12 and K21

Working widths (m)1.2 – 5.41.2 – 5.4
Production speeds (m/min)150 m/min
Weight range (g/m2)(20 to 2000 g/m 2 )20 up to 130 g/m2
Capacity (kg/h/m)450 kg/h/m300 kg/h/m
Raw materialCotton, reclaimed and recycled fibers of 1.7 to 200 dtexSynthetic and viscose rayon 1.7 to 3.3 dtex
ApplicationsInsulating and mattress fabrics, filling material and mattress covers, under-carpets as well as wadding material for upholstery and automotive industryHygienic and sanitary applications, for interlinings and basic material for cleaning cloth as well as coating carriers

Schematic view of the air laying system

Schematic View of the Air laying System

Schematic view of the DOA airlaying system

Schematic View of the Doa Air laying System

Chicopee airlaying system

Chicopee Airlaying System

  • Air velocity (140 m/s)
  • Surface speed of the cylinder ( 20–60 m/s)
  • Staple fibers ranging from 13–75 mm

Spinnbau airlaying system

Spinnbau Airlaying System

Thibeau hybrid card airlaying machine

Thibeau Hybrid Card Airlaying Machine

Thibeau hybrid system

  • Typical MD/CD ratio of 1.2–1.5:1
  • Production rate of 200–260 kg/h/m
  • Web weights of 35–200 g/m 2
  • Fiber types cotton, viscose rayon, PET, PP, PA
  • Fiber length of 10–40 mm.



Turbo-card RC 2-6 TR

Turbo-Card Rc 2-6 Tr

Turbo-Unit and Turbo-Card

  • The turbo-unit TU is either fed by pre-carded webs via a feed plate intake or may be combined with a random card.
  • The turbo-roll is equipped with carding segments.
  • Aerodynamical web-forming by centrifugal force, doffer fan and suction conveyor.
  • Lower to medium fiber fineness range.
  • Staple length: approx. 10 – 80 mm.
  • Web weight: approx. 25 – 450 g/m2
  • Throughput depending on fiber fineness and fiber type: up to approx. 400 kg/h/m of working width.
  • Working widths: up to 4.000 mm
  • Web speed: approx. 20 – 120 m/min

Airlaid web formation machine 008-0445 of Laroche S.A.

Web Forming Machine

Laroche System

  • Web weight ranges from 300 to 3000 g/m 2
  • Production speed of up to 10–15 m/min
  • Fiber length should be in the range 20–75 mm
  • Cotton, man-made, glass fibers
  • Hemp, flax, sisal, coconut
  • Bed covers, mats, upholstery and insulation material, carrier material for carpets, industrial and geotextiles as well as furniture textiles

General properties of airlaid fabrics

  1. High isotropicity
  2. High loft (if required)
  3. High porosity (95–>99%)
  4. High absorbency and wicking rate
  5. Soft handle
  6. Adequate tensile strength
  7. Good resiliency (compression recovery)
  8. High thermal resistance.

Airlaid and random cards: end products

  • Chemical bonding: napkins, table cloths and wipes.
  • Thermal bonding: nappies (different components, i.e., acquisition layer, distribution layer and absorption core), feminine hygiene/incontinence products and insulation.
  • Spunlacing: wet and dry wipes for domestic and industrial applications, medical textiles (including disposable gowns, curtains, wound-care dressings, bed sheets), filtration media.
  • Needle punching: interlinings and shoe linings, wadding, medical and hygiene products, geotextiles and roofing felts, insulation felts, automotive components, filters, wipes.

Combination of unidirectional and cross directional web

Combination of unidirectional and cross directional web

Two carding machines aligned in tandem
Two carding machines aligned in tandem. a) Card; b) Conveyor belt c) Comb
Oscillating cross lapper
Oscillating cross lapper (camelback)
a) Card: b) Conveyor belt: c) Carded web: d) Oscillating laying device; e) Delivery belt (apron)

Cross lapper with horizontal laying device

Cross lapper with Horizontal Laying Device

Tasks of the web-laying machine

  • Increasing the web mass
  • Increasing the web width
  • Determining the web strength in the length and cross directions
  • Improving the end product quality

Lap drafter VSTG
Working width up to 7.000 mm. Individual servo-drives for 4 drafting zones with infinitely variable drafts. Only little changes of batt weight regularity by fiber re-orientation increase strength in md.

Lap Drafter Vstg

Merits and limitations of card – cross lapping and air laying

Carding Cross lappingAir Laying
Very wide widths of fabrics up to 15-20 metres are possibleWidth is limited up to 2-3 metres
A wide range of fabric weights from 75 to 2500gsm are possible by varying take-off speed of laying lattice in relation to speed of delivery LatticeGSM lower than 150 are not normally possible.
Highly uniform Fabrics can be made in respect of weight per unit length. Variations in weight per unit length in longitudinal and lateral directions are within 5%It is difficult to achieve good uniformity in weight/unit length particularly in low weight nonwovens.
Ability to process a wide range of staple lengthsMainly suitable for short fibers. With long fibers it is difficult to get satisfactory uniformity.
There is no randomisation between lateral and vertical planes. Anisotropy in strength is also present in the lateral plane. Strength is generally higher in cross direction than longitudinal direction though this is minimized to some extent by the use of randomising rollers in carding and web drafting prior to bondingFiber orientation is random in all the 3 dimensions though longitudinal direction strength is slightly higher than cross direction strength. The isotropic distribution gives a high degree of insulation properties. But strength is reduced as fibers in the vertical direction do not contribute to strength. Further anisotropic material cannot be made Batt formation involving carding.

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