Non Woven Fabric
Dr. Jimmy Lam
Institute of Textiles & Clothing
Non-woven
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Introduction
Web formation methods
Bonding Systems
Discussion
Introduction
• Fabrics can be made from fibres as well as
from yarns.
• Conventional fabric production:
– Fibre  Yarn  Fabric (knitting or weaving)
• Non-woven production
– Fibre  Fabric
• It eliminates the yarn production process
and makes the fabric directly from fibres.
Introduction (2)
• The great advantages in non-woven fabrics is the
speed with which the final fabric is produced.
• All yarn preparation steps are eliminated, and the
fabric production itself is faster than
conventional methods.
• To produce 500,000 meters of woven sheeting
requires 2 months of yarn preparation, 3 months
of weaving on 50 looms and 1 month for finishing
and inspection.
• Non-woven fabric can deliver the same quantity of
sheeting within 2 months from order.
Introduction (3)
• Not only are production rate are
higher for nonwovens, but the
process is more automated, requiring
less labour than even most modern
knitting or weaving systems.
• The nonwoven process is also
efficient in its use of energy.
Production Rate
Fabric production
method
Weaving
Rate of fabric
production
1 m/min
Knitting
2 m/min
Nonwoven
100 m/min
Applications
• Nonwoven fabrics can be engineered to give
a wide variety of properties.
• Nevertheless, their aesthetic properties
(handle, drape, appearance) are such that
they are not in direct competition with
conventional fabrics in the outerwear
market.
• Woven and knitted fabrics will not be
replaced by nonwovens in the near futrue.
• Currently, the main areas of growth in
nonwovens are in geotextiles, medical and
hospital uses, disposable products and
filters.
Making Non-woven products
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There are normally two steps for
making non-woven products.
They are:
1. Web formation; and
2. Bonding systems.
Web formation
• A nonwoven fabric is basically a web
of fibres held together in some way.
• The web may be made of staple
fibres or filaments, or from portions
of polymer film.
Web formation from
Staple Fibres
Web from staple fibres
Carding for parallel-laid web (1)
• Carding is a time-honoured way of making web
from staple fibres.
• In a carded web the fibres are aligned more or
less parallel to each other and to the direction in
which the card produces the web. Such web is
stronger when pulled lengthwise than crosswise
because there is more friction between the fibre
in lengthwise direction.
• Carded webs are usually thin, they may be too thin
for some nonwoven end-uses. To increase the final
thickness, a number of webs can be layered.
Photos
Parallel-laid web from carded
fibres
Webs from staple fibres
Cross-laid web (2)
• To increase the strength of web in
both lengthwise and crosswise
directions, cross laid web is used.
• To achieve this, the fibres which
make up the web will be orientated
equally in both lengthwise and
crosswise directions.
Photos
Cross Laid-web
The properties of cross-laid webs do not vary with
direction as much as do those of straight-laid web
Web from staple fibres
Random web (3)
• The Rando-Webber creates such a
randomly orientated web by blowing the
fibres about in a stream of air and then
sucking them onto the surface of a
perforated drum to form a layer.
• This randomizing process produces a
remarkably uniform web from staple
fibres.
• Dry-laid (air-laid card) webs account for
three-quarters of non-woven produced
Photos
Random Webs
The Rando-Webber gives a randomly orientated web, with no
Directionality in its properties
Other Web formation
methods
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Apart from carding methods (drylaid), webs from short staple fibres
are created by
1. Wet laying;
2. Electrostatic web formation; and
3. Spraying.
Wet-laying
Paper-making from web
• Wet laying is used in paper-making. The
pulped fibres are mixed with water and then
scooped into uniform layers on wire screens
or on rotating, perforated drums.
• Short, pulped acrylic fibres are made into a
wet-laid web from a salt solution. As the
water evaporates, the salt chemically bonds
the fibres into a strong, synthetic, water
proof paper.
Web formed by
electrostatic laying
• In electrostatic laying, fine fibres
are given a static electric charge
between the plates of a condenser,
and are then allowed to fall on a
moving belt to form a randomly
orientated but uniform web.
Spraying method
• Short thermoplastic fibres can be
SPRAYED onto a belt to produce a
random web.
• The are subsequently fused by the
application of heat and pressure.
Webs from filament
Webs from filament
• It is possible to tangle filaments together to form
a web. Such webs are much stronger than web made
from staple fibres.
• Freshly extruded filaments are allowed to drop in
curls and spiral onto a moving belt.
• The belt may contain patterns outlined in pins to
form lace-like patterns.
• The thermoplastic filaments are welded to each
other to form a strong fabric suitable for curtains,
tablecloths.
• Sometimes, the filaments are textured before web
formation, this allows greater extensibility of the
fabric in use.
New web formation method
• Spun-laced webs is a new method of entangling
fibres to create lace-like nonwoven fabrics uses
fine, precisely controlled, jets of water.
• When the jets pass through the web of fibres,
they form a small vortex at each point of contact.
• This creates sufficient fibre movement to entangle
the fibres.
• The resultant fabric does not need any further
reinforcing by heat or adhesive.
• It is pliable, resistant to damage during washing,
drip-dry, light, warm and soft, excellent for
curtains, table cloths and other lace-type
application.
Conclusion
• This section we discuss what non-woven is
and their applications in textile.
• We also discuss the web formation
methods for both staple fibres and
filament fibres.
• Next section, we will discuss the bonding
systems for non-woven in order to make
the fabrics with certain thickness and
weight for specific end uses