Basic non woven And technology of non woven Uses of non woven fabric

1. Que 1- write a note on end uses of non woven.
Ans – Application of non woven fabric.
 Personal care and hygiene - Baby diapers, feminine hygiene
products, adult incontinence items, dry and wet pads, but also
nursing pads or nasal strips, bandages and wound dressings.
 Healthcare - like operation drapes, gowns, and packs, face masks,
dressings and swabs, isolation gowns, surgical gowns, surgical
drapes and covers, surgical scrub suits, caps.
 Clothing - interlinings, insulation and protection clothing,
industrial workwear, chemical defence suits, shoe components,
etc.
 Home - wipes and dusters, tea and coffee bags, fabric softeners,
food wraps, filters, bed and table linen, etc.
 Automotive - boot liners, shelf trim, oil and cabin air filters,
moulded bonnet liners, heat shields, airbags, tapes, decorative
fabrics, etc.
 Construction – roofing and tile underlay, thermal and noise
insulation, house wrap, understanding, drainage, etc.
 Geotextile - asphalt overlay, soil stabilization, drainage,
sedimentation and erosion control, etc.
 Industrial – cable insulation, abrasives, reinforced plastics,
battery separators, satellite dishes, artificial leather, air
conditioning, coating.
Que -3 – Briefly describe various finishing process of non woven.
Ans – Non woven fabrics require certain desirable properties like
mechanical finish and chemical finishes. Suitable method are used to
create finishing effect.
Mechanical finishing -

2.  Splitting and winding – This process is used to produce non
woven fabric of high density. That is high basis weight and low
thickness.
 Perforating – This process of finishing is used to enhance the
wicking property as well as softness and drape of fabrics.
 Drying- During the process of manufacturing the nonwoven
fabrics are subjected to tension, which cause the fabrics to
distort dimensionally. That is the fabrics get stretched in length
and shrunk in width.
 Calendering – The process of calendering can be said to be
more severe from of compaction process. The purpose of
calendering is to make the fabric compact with decrease
thickness and smooth surface.
 Singeing- The purpose of singeing is to remove the protruding
fibres from the surface of the fabrics. The method of singeing is
basically categorized as direct and indirect singeing.
 Shearing- It is also known as cropping or cutting, it is used for
removing surface fibres.
 Raising – Raising is a process to create fibrous pile structures
on the surface of a pre-formed fabric. It increases the bulk and
improves the look and feel of nonwovens.
 Polishing- Polishing improves the surface lustre in fabrics.
Surface fibres are reoriented in one preferred direction during
polishing, thereby increasing the lustre.
 Softening- This process aims at enhancing bulk, softness and
drivability of fabric by reducing its stiffness. In order to increase
fabric softness further they are treated with enzymes and
chemicals.

3.  Heat setting- Heat setting is carried out to achieve the
dimensional stability of nonwoven fabric containing
thermoplastic fibres.
Chemical finishing-
 Antistatic agent- These finishing agent helps to prevent the static
charge build up specially on synthetic fibres.
 Antimicrobial finishes- These types of finishes are used to prevent
the biological degradation of fabric by bacterial or fungal growth.
 Lubricants- These are mostly used to reduce friction, whether it is
fibre to fibre or fibre to metal.They also help imparting softness to
certain fabrics.
 Waterproof finishes- This type of finish is used to inhibit wetting
of fabrics. They can be applied to spraying, padding in aqueous
dispersion form .
 Softeners- they provide softness to the fabrice. Softeners which
are hydrophilic in nature also increase the wettability of the
fabric.
 Stiffeners- Stiffeners are the finishes which help to add stiffness
to the fabric. They are introduced to increase abrasion resistance
by welding of adjacent fabric.
 UV Stabilizers- They are used to protect the adhesives and
polymers used as binders in the fabric from being degraded by
harmful ultra violet light.
Que -4 Write a note on various non woven bonding techniques.
Ans- Web bonding - Web has to be bonded using various methods to
provide strength to the non woven . The type of bonding has a direct
influence on the fabric properties in terms of strength flexibility,

4. softness etc. some webs are bonded using more than one technique to
achieve specific fabric characteristics
 Mechanical technique-
Needle punching- barb needles are used
Stitch bonding – knitting needles are used
Spun lacing – hydroentangling
 Chemical method-
Adhesive binders by a range of processes including spraying,
printing, saturating and foaming. Solvent method Softening or
partially dissolving fibres with a solvent to provide self – bonding
surfaces.
 Thermal method –
It involves heat or pressure to fuse and weld fibres together at
points of intersection or in patterned bond sites that involve
including a fibre with a lower melting point in a web.
 Differential shrinkage -
Involves some type of cotton staple nonwoven treated with
sodium hydroxide. The caustic causes the cellulose based fibres to
curl and shrink around one another so as to bind fibres in the
web.
Que 5- write a note on fibre used in nonwoven.
Ans - Non-woven were invented to use the waste from spinning into
cheap disposable, but now a day virtually all kinds of fibres used
depending on end use of products.
 Natural fibre /regenerated fibre are biodegradable hence widely
used in disposable non woven.
 In USA 90%of non woven were produced from polyester ,pp
,viscose and glass fibre out of which 49% ,consume polyester
staple fibre.

5. 1. Cellulose fibres due to hydroscopic are used for absorbent .
2. Cotton linters are used for a disposable purpose
3. Wood being high cost is used in bonded fabric from reclaimed
wool
4. Wool pulp has high water absorbency .bulk and low cost is used
for disposable absorbents like diapers ,tissue etc.
5. Viscose rayon is cheap to produce but has high absorption and is
used for disposables sanitary products and wipes.
6. Regenerated cellulose fibre like cuprammonium rayon are also
used for high absorption sanitary disposal.
7. All synthetic fibres are resistant to mildew & superior outer
surface for surgical bandage ,common fibre have high strength ,low
weight fatigue character ,chemical and temp resist corrosion resist
,high thermal & electrical conductivity. If it is preferred for air craft
sports etc.
8. Polyester have hydrophobic mesh dry outer surface of low weight
disposable even though inner absorbent is soluble
9. PP has high strength abrasion resistance ,sun light resistance are
used for protecting screens.
10. Polyamide 6 or polyamide 66 are preferred where non woven
need to absorb water.
11. Carbon fibre is light weight with strength ,fatigue character
,chemical& temp inert ,corrosion resistance high thermal &electrical
conductivity is used for good conductivity ,chemical & corrosion resist
etc.

6. 12. Glass fibre are used for filtration and thermal insulation due to
high strength, good conductivity, chemical and corrosion resist etc.
13. Aramid (kevlar) organic fibre having high toughness , self-
extinguishing is ideal for ballistic application.
14. Aramid organic fibre having high toughness ,self extinguishing is
ideal for ballistic application
15. Nano fibre with 0.04-2 micron diameter are used for finer webs
0.0005-0.015 oz/yd2
Bi- component fibres :two nylon polymer extruded side by side
through a spinneret .differential crimping or melting point give
advantage in bonding.
Que 8- with suitable sketch describe wet laid non woven techniques.
Ans - Wetlaid is used for paper making.
 In wet laid uses longer fibre.
 If more than 70% of material is wood pulp then that is a paper, 5-10
% of non woven roll goods are produced using these method.
 The fibre are dispersedin water and then laid on a wire mesh to filter
the liquid and form a web, which is transferred to A drying felt before
finally being heat cured in a continue process.
 This produce a web in which fibre are randomly oriented.
Process sequences :-
 Wetting and dispersing fibres in water.
 Transport of fibre dispersion to wards web – forming device.
 Forming fibre web on the moving endless screen or perforated
drum.
 Removing water by suction pressure and drying.

7. Fig :- wet laid process
End uses of wet laid –

8. Que 9- with the suitable sketch describe felt loom.
Ans – felt loom – It produce one dimension fabric like geo textile,
interlining, home furnishing etc.
 In felt loom Barbed needles are used.
 The web passes between two plates, a bed plate on the bottom
and a stripper plate on the top. Corresponding holes in each plate
matches the needle gauge and alignment in the needle board.
 The needle board is the base unit in to which needles are
arranged in non alignment arranged.
 The needle board then fits in to the needle beam the stroke of
which various from 30 to 60 mm.
 The gauge of the needle is defined as the number of needles per
square inch area.

9.  For the coarser fibre 12 to 16 gauge needle are used.
 For the synthetic / finer 25 to 40gauge needle are used.
 Vertical up and down movement of needle causes penetration of
the needle through the thickness of the web.
 The feed roll and draw roll rotation facilitate the web motion as it
passes through the needle loom.
 Width of needle punch loom 2 to 16 m, speed 150 m/min.
Que 10- sketch and describe barb needle.
Ans – Barb needle – Barb needle are the heart of needle punching
process.
 A needle has the following parts : crank , shank, blade point.

10.  The crank is the 90 degree bend on the top of the needles, it seats
in top the needle board. The shank is the thickest part of followed
by the intermediate blade which fits directly in the needle board.
 The blade is the working part of the needle having barbs that
passes in to the web and interlocks the fibre. Various cross section
of the needles blades include pinch blade, star blade, conical
blade etc.
Fig – needle blade
Point – The lower portion of the needle.
Type of point-
1. Ball point
2. Light ball point.
3. Rounded set point.
4. Polished point.

11. Fig :- point
Types of barb –
There are four type of barb. 1- Regular barb
2- Medium barb (MB)
3- Close barb (CB)
4- High density barb (HDB)
Fig :- type of barb.

12. 1- Regular barb - Regular barbed needle are commonly used. It
results in higher thickness of needle punched fabric.
RB is invariably preferred in pre needling and for high lofts and
wadding.
2- Medium barb – MB 4.8 mm spacing improves needling
efficiency and results in more compact products.
This needle is therefore preferred in waste fibre felts used as
underlays in carpet and shoddy.
3- Close Barb – CB with spacing b/w barbs 3.3mm in preferred in
finish needling.
So close barb needle results in a more compact and stronger non
woven then regular.
4- High density barb – this needle is preferred in finish needling
with thin products.
These needle are preferred for manufacture of synthetic leather
automotive trunk liner, shoe etc.
Geometry of barbed needle- The barb is known to the main working
component of needles a barb is characterized by kick up, barb angle ,
throat length, Barb heights.

13. Que 11- write a note on web parameters affecting felt properties.
Ans – web parameters-
 Fibre length - Higher length of fibre causes less slippage
increasing strength above 40 mm is preferred but around 80 mm
gives uniform strength.
 Fibre fineness – web becomes compact with reduction of fibre
denier which increase strength due to higher specific area of
contact. But finer fibers are weaker giving more breakage. Also
pore size decrease.
 Surface roughness increase entanglement by less slippage bet
fibre and needle. Tribal fibre are better than round c/s.

14. Que 12 - Describe spun bonded non woven.
Ans – Spun bonded - Spun bonding is one of the most popular
methods of producing polymer-laid nonwovens.
Spun bonded nonwoven fabric are composed of continues
filament produced by a integrated fibre spinning web formation
and bonding process as it eliminate intermediate steps.
Fig – spun bonded process
This process is based on the melt spinning technique. The melt is
forced by spin pumps through a spinneret having a large number
of holes. The quench air ducts, located below the spinneret block,
continuously supply the conditioned air to cool the filaments.
There is also a continuous supply of auxiliary room temperature
air. Over the line’s entire working width, ventilator generated
under-pressure sucks the filaments and mixed air down from the
spinnerets and cooling chambers.
Characteristics and properties of spun bonded webs are:
1. Random fibrous structure
2. Generally the web is white with high opacity per unit area
3. Basis weight range between 10 – 200 k/m2

15. 4. Fibre diameter range between 15 and 35 m.
5.Web thickness range typically 0.2 – 1.5 mm.
6. High strength to weight ratios compared to other non woven,
woven and knitted structure.
7. High tear strength (for area bonded webs only)
8 . Good fray and crease resistance.
Que 13 - write a note on stitch bonded non woven.
Ans - It is formed by stitching of the fibre bundle with fibers or
yarn.
 Fabric generally may have clear stitching pattern on one side
or both sides.
There are three main type of stitch bonded fabrics.
1. Fabric with one side stitch.
2. Fabric with one side stiches and one side projection of Pile
of pleating fibre.
3. Fabric with two side stitch.
 Generally in stitch bonded fabric, yarn stitches alinged with
in the fabric plane.
 The performance of the stitch bonded non woven are
dependent on the web density and structure, machine
gauge.
Que 7- with suitable sketch describe random web making.
Ans - Random web – Random fibre orientation in the web is
achieved by incorporating randomizing rolls in the card.
 Random rolls are generally located between the main
cylinder & doffer.

16.  The configuration diameter & position of the randomizing
rolls are different for the different manufacturer.
Que 6- write a note on web making for non woven.
Ans – The web may be made of staple fibres, filament, or from
polymer film.

17. Dry laid – For the production of non woven from staple fibers, a
carding process is required for fibers separation and web
formation. The website produced by this system are known as dry
laid.
Parallel laid - In the parallel laids webs the fibers are laid in a
length wise orientation.
 This implies that this type of web has greater strength in the
length wise direction than the transverse direction.
 According to the demand of mass and fibre type the parallel
laid web permits the reputation of fibrous web.
 The number of layers in the web decides the number of
cards required.
Fig :- parallel laid
Cross laid - Cross laid web is made by either pendulum
conveyor ( vertical cross lapper) or Horizontal cross laper which
delivers the web at a specific rate on to a take up conveyor and
angle to the direction.
 The web thickness and fibre direction is achieved in the
cross laid web.
Fig:- Cross laid

18. Electrostatic flocking - Fine fibre are given a static charge
between the plates of a condenser, and are than allowed to fall on
a moving belt to form a randomly orientated but uniform web.
Air laid - Air laid process is non woven web forming process in
which the web of fibres is produced by the dispersion of fibers
ranging from 1-4 mm.
 Initially the fibres are dispersed in to a fast moving air
stream and belt or perforated drum under pressure or
vaccum.
 Finally the fibres condense on the surface of moving belt or
drum in order to create web.
Fig :- Air laid web formation.
Wet laid - wet laid is used for paper making.
 In wet laid uses longer fibre.
 If more than 70% of material is wood pulp then that is a
paper, 5-10 % of non woven roll goods are produced using
these method.

19.  The fibre are dispersed in water and then laid on a wire
mesh to filter the liquid and form a web, which is transferred
to A drying felt before finally being heat cured in a continue
process.
 This produce a web in which fibre are randomly oriented.
Spun laid – Spun bonding is one of the most popular methods of
producing polymer-laid nonwovens.
Spun bonded nonwoven fabric are composed of continues
filament produced by a integrated fibre spinning web formation
and bonding process as it eliminate intermediate steps.