Recent development in needle punching nonwoven manufacturing

1. Page1
Seminar report on
"Recent development in needle punching nonwoven
manufacturing"
Submitted in partial fulfilment of the
Requirements for the award of the degree of
BACHELOR OF TECHNOLOGY
In
TEXTILE TECHNOLOGY
Submitted by
Vijay Prakash (1704460060)

2. DEPARTMENT OF TEXTILE TECHNOLOGY
UTTAR PRADESH TEXTIL TECHNOLOGY INSTITUTE
,KANPUR (U.P)
JULY,2021

3. Page2
Recent development in needle punching nonwoven manufacturing

4. Abstract:
This paper reportsan exploratory study on the production and measurement of
the air permeability, mechanical properties, pore size distribution and filtration
efficiency of different nonwoven fabricspr oduced by systematically changing
the machine variables to influence the physical parameter sof the fabrics. Only
flax fiber waste wasutilized for this tr ial, so that the possibility of value
addition to a cheap sour ce of raw mater ial could be explored. The changesin
air per meability wer e interpreted in ter msof fabric density profile and pore
size distr ibution. The tensile str ength, fiber or ientation distr ibution and bond
str ength between the layersof multi-layer ed fabricswer e investigated. The
filtration parameters, such asfiltration efficiency, dust holding capacity and
pressur e dr op, were evaluated. Fur ther mor e, the effect of calender ing on
pore size and filtr ation propertieswas evaluated to explore the possibility of
fine-tuning the perfor mance of filters. The resultsin thisstudy showed an
overall impr ovement in all filtr ation characteristicsdue to the calender ing
operation.

5. Page3
filter pressapplication in textile effluent treatment plant. For filter pressdevelopment, the nonwoven
fabric wasr einfor ced with the nylon scr imasthe central layer in or der to withstand the filtr ation
pressur e. The nonwoven fabricswer e developed using differ ent denier polyester fibresand changing
punch density. The influence of fibre finenessand punch density on the propertiesof
nonwovenswasinvestigated. The filtr ation parameter ssuch as filtr ation efficiency, dewater ing
efficiency, blinding tendency and cake dischar ge properties of the developed nonwoven filter
fabricsfilter fabricswer e evaluated and compar ed with existing woven fabric filter media. The
influence of calender ing on the filtr ation properties of the nonwovenswasalso studied. The
resultsshowed that bur sting str ength of the developed nonwovensincr eased with incr ease in fibre
finenessand decr ease in punch density. It wasalso found that the air per meability of the developed
nonwoven svaried inversely in relation to punch density and the proportion of fine fibres. It wasobser
ved that developed nonwovens had 8%higher filtr ation efficiency and 6% higher dewatering
efficiency compar ed to the existing woven fabric filter media. The blinding resistance and cake
dischar ge properties
were slightly lower than that of woven fabric filter . It wasfound that calender ing impr oves filtr
ation propertiesof the developed nonwoven fabrics.

6. Introduction:
The objective of the current study waste compare the properties and characteristics of nonwoven
fabrics made fromreclaimed fiberswith those of or dinar y nonwovens. Moder n developmentsin
air filtr ation media have been in the field of electrostatic filter sin which fibersaredevelopmentsin
air filtr ation media have been in the field of electr ostatic filter sin which fibersare electr ically
charged to attract oppositely char gedpar ticulates, thus
impr oving filtr ation effectivenessdue to decr eased pressur e dr op acrossthe filter and
increased particle holding ability. The definition of perfor mance for the purpose of any product
isan impor tant factor for the design. The pressur e dr op isan indication of the
resistance to air flowof the filter . It isimpor tant, both when the filter isclean and when it is barren
due to deposition of particleson the sur face which resultsin the for mation of a filter cake. Pressure
drop is also a measur e of the energy requirement and the cost associated with the filtr ation
operation. Disadvantagesof single-layer ed needle-punched nonwoven mater ials for use in air filtr
ation applicationsinclude the non-unifor mity of the web and distr ibution of pore size which result
in poor ser viceability due to inadequate str ength in the dir ection of air flow. Appar ently,
thisapproach islow cost due to differ ent fibersand str uctur esemployed, besidesthe
heterogeneousbehavior of the mater ial in ter msof cer tain mechanical and physical properties.
Amulti-layer ed reclaimed nonwoven fabric can be produced cost effectively and may offer a
viable solution for such applications.
1.METHODOLOGY:
Mater ial Pr eparation The most widely accepted preparatory method is'mechanical re- fiber
ization'. Thisinvolvespassing cut fabric piecesthrough two nipped feed roller s, which gr ip the cut
fabric while a rapidly rotating cylinder covered with shar p metallic pins mechanically opensthe
fabric into smaller fractions. The product of mechanical pulling typically consistsof a mixtur e of
individual fiber s, yarn segmentsand smaller fabric pieces.

7. Page4
Fur ther separ ation stagesar e employed to increase the reduction of the segmentsand pieces into
fiber for m. The fiber isthen collected on a vacuumassisted dr umand fed out of the machine. The str
ucture of the textile being refiberized influencesthe dimensions, degree of separ ation, and
homogeneity of the fibrousproduct. Mor e loosely for med str uctures, such o have lower density
which yieldslonger fiber lengthswhen reprocessed.
2.Web For mation:
We used dry laid web for mation in thisprocess. The most common form of dry laid web formation
is carding, but heavier weight webscontaining waste fibersare also commonly for med into
websusing Gar nett machines. Immediately after car ding, the webs were parallel lapped, which
involved laying the websover one another in the machine dir ection to impr ove final web unifor
mity further without changing the predominant fiber or ientation. The resulting web isanisotr opic in
nature, in that fibersare preferentially aligned in the longitudinal dir ection. After subsequent
bonding, the final fabric tensile str ength will tend to be higher in the longitudinal dir ection. While
most air laying techniquesdesigned for waste fiber recycling have traditionally utilized revolving
pinned rollersto transpor t fiber s, a second method of web for mation involvesconverting very
short fibers(lessthan 10mm) using an adapted air laying technique of the sifting type. The shor t
fiber sand particles that are recover ed fromthe clothing waste which are incompatible with both car
ding and garneting were found to be particularly suited to conver sion using the air lay method. The
fibers were separated efficiently during processing and for med a uniformweb with isotropic
properties.

8. NEEDLE PUNCHING:
Premixing and opening were achieved by a CMC* Rando Cleaner . The fibers were then fed
through the chute feed system, which fed the fibers to a 51 cm(20 in) pneumatic card. From the
car d, the fiber web was fed onto a 61 cm(24 in) Automatex cross lapper conveyor system.
The for med and cross-lapped webs were then needle punched on a 53 cm(21 in) Automatex
needle loomata rate of 200 str okesper minute and a deliver y speed of one meter per minute to
yield nominal 1700 g/ m2 sample fabrics.
CALENDERING PROCESS:
The needle punched fabrics were squeezed together and thermally molded to comparable
thicknesses and densitieson a Carver pressusing 12.7 mm(0.5 in), 6.4 mm(0.25 in) and 3.2 mm
(0.125 in) frames. The minimum thickness was achieved by compressing the nonwoven fabrics
without a frame at a pressur e of 30 tons. The test specimen manufacturing procedure was
carried out in the following sequence. The calendar ing device washeated to 80°C, and the
sample, frameswer e placed into the device. The sampleswer e then compressed for 6 min at 5
tonsof pressur e and wer e cooled under pressur e for 6 min. Finally, the pressure was released
and the sample wastaken out of the calendaring device. After the samples were compressed,
they were cut into 30.5 cm by 30.5 cm(12 in by 12 in) test specimens.
SAMPLE PREPARATION:
Nonwoven fabric sampleswer e set on a laboratory model card prepared with univer sal car d
clothing, crosslapper and a needle-punching loomcontaining 6000 needlesper running meter .
The variationsin the substantial and structural parameter sof the nonwoven fabrics produced wer
e achieved by properly changing processvar iables, such asthe standar d feed

9. Page5
roller speed, cr oss-lapping speed, str oke frequency and depth of needle penetration. Gr oz- Beckert felting needles, with
technological condition as15x18x32x3 R333 G3027, wer e used for the needling. However , 80 °Cwasa minimumtemper
ature that enabled usto achieve
resultsin ter msof the density, compactnessand pore size distr ibution. The higher temper ature could cause damage to
cellulose and hemicellulosesin the natural fiber str ucture and would
require higher energy consumption.
EXPERIMENTAL
All fabric sampleswer e habituated under standar d atmospher ic conditionsof 21 ± 1 °Cand 65 ± 2 %RHfor at least 24
hoursbefore testing. The area weight of the fabricswas measur ed accor ding to ASTMD3776. The measur ement of fabric
thicknesswasper for med accor ding to ASTMD5729-95, which wasadopted using a FAST instr ument at a constant pressure
of 4.14 ± 0.21 kPa or 422 ± 21 kg/ m2 . The fabric tensile str ength wasmeasur ed on an Instr on tensile tester accor ding to
ASTMD5034. The reclaimed nonwoven fabricswer e tested for their separ ation force on an Instr on tensile tester accor ding
to the Peel or
Str ipping Str ength test method defined in ASTMD903-98. The force required to separ ate two single layerswastaken asa
measur e of the bond str ength between layersdue to the needle- punching process. The air per meability test wascar r ied out
on an air per meability testing apparatusaccor ding to the ASTMD737- 96. The air per meability wasexpr essed in ml/ s/ cm²
at a prescr ibed water pressur e differ ential of 98 Pa between the two sur facesof the fabric. The dimension of fabric pore size
can be carried out by var ioustechniques, such asprojection micr oscopy, scanning electron micr oscopy, optical micr oscopy
inter faced with digital image processing, and special purpose techniques, such asextrusion flowporometr y. The pore size
and itsdistr ibution wer e calculated on the Capillar y Flow Por ometer accor ding to ASTME 1294-89. For the dimension of
Jour nal of Engineered Fiber sand Fabrics151
http:/ / www.jeffjour nal.org Volume 9, Issue 1 –2014 filtr ation parameter s, a standar d test method asper Amer ican
Society of Heating, Refrigeration and Air Conditioning Engineers ASHARE 52.2, wasadopted to evaluate filtr ation
efficiency, dust holding capacity and
pressur e dr op. Air Flow (m³/ sec) = Air Velocity × Filter Ar ea Dust increment per min (g/ min) = total dust/ total time.

10. RESULTS AND DISCUSSION:
1.Air Permeability :
Air permeability is the most important property of nonwoven materials for the application
in dry filtration. The evaluation of air permeability and its relationship with physical
Parameters of the fabric, such as weight, thickness and density are reported in the figures
below. In general, the air permeability decreases with the increase in fabric weight. While
with increase in fabric weight, the fabric becomes thicker as well as denser , resulting in
consolidated fabric structure, though the amount of pores increases with the increase in
the number of fiber s, the pore size becomes smaller . This research reported that the air
permeability decreased with the increase in fabric weight in case of reclaimed chemical
bonding by calendaring process respectively. FIGURE 1. Relationship between fabric
thickness and air permeability. FIGURE 2. Relationship between fabric density and air
permeability.
Journal of Engineered Fiber sand Fabrics152 http:/ / www.jeffjour nal.org Volume 9, Issue
1
–2014 FIGURE 3. Relationship between GSM and air permeability.
DEPTH OF NEEDLE PENETRATION:

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In the case of a multi-layer ed nonwoven str ucture, wher e two or mor e nonwoven fabricsare needlepunched
together to forma fabric, the delamination (division) str ength isa significant property which deter minesitsser
viceability. In general, the delamination str ength washigher at higher depthsof diffusion; thiswasdue to mor e
intensive inter mingling of the two single layer s. Almost certainly the fibersfromthe top fabric layer became mor
e entangled with the fibersfromthe bottomlayer at a greater lowest point of needle penetration, thusrequiring a
higher force to divide them. At a lower depth of penetration, asthe needleshad to penetrate acrossthe whole depth
of the top fabric, lessintensive binding occur red and the two individual layerswer e bound only at the sur face,
thusresulting in their easy separ ation. Also, a much higher needling force will be required in for ming multi-
layer ed fabricsand special needles, which cause a minimumdistur bance to the top fabric layer when the
needlesar e withdr awn fromthe fabrics, will be needed.
PORE SIZE AND THEIR DISTRIBUTION:
The function of needle punched nonwoven fabricsin dr y and wet filtr ation ismainly
deter mined by the pore size and itsdistr ibution. The design consider ation for filter fabrics for a particular
application beginsfromthe selection of the fibersto achieve the
appropriate pore size to filter out the desir ed size of the particulates. The micr o-poresshould be smaller than the
minimumpar ticle size to ensur e the desir ed filtr ation efficiency. This should be achieved with the minimumpr
essur e dr op acrossthe filter and without causing any distur bance to the pore geometr y. Por e size data are
presented in Table I and Figur es3 and
4. TABLE I. Minimum, mean and maximumpor e size. Jour nal of Engineered Fiber sand Fabr ics 153 http:/ /
www.jeffjour nal.org Volume 9, Issue 1 –2014 0 10 20 30 40 50 60 0 200 400 600 800 1000 1200 1400 1600 0
10 20 30 40 50 60 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 pore size FIGURE 4.
Sample 1 pore size and itsdistr ibution. FIGURE 5. Sample 2 pore size and itsdistr ibution. TABLE II.
Evaluation of filtr ation properties. Jour nal of Engineered Fiber sand Fabr ics154 http:/ / www.jeffjour nal.org
Volume 9, Issue 1 – 2014

12. EVALUATION OF FILTRATION PROPERTIES:
Filtration properties provide information about the serviceability of the material in addition to
its functional performance. The dust retention capacity of the nonwoven and formation of a
“block” retard its purposeful capacity due to an increased pressure drop across the fabric.
Three samples of reclaimed needle punched nonwovens were tested to calculate filtration
properties on a dust filtration device, both before and after a calendering operation. The
filtration properties, such asdustarrestance, dust holding capacity and resistance to air
flow (pressure drop) were evaluated and the resultsare shown in Table II. The results indicate
an improvement in filtration properties, such as dust weight arrestance and dust holding
capacity, which supports our assumption that the post-needle- punching calendaring
operation can impar t beneficial properties to the fabric. Table II compares the filtration
parameter sof un-calender ed and calender ed samples of reclaimed needle-punched
nonwovens. The results in this study show overall improvement of all filtration characteristics
due to the calendaring operation.
CONCLUSION:
This was an investigative study proposed for utilizing reclaimed waste fibers for developing
inexpensive disposable filtration media for air and dust filtration, mainly for household and

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industr ial air -conditioning. The production of reclaimed samplesby combining differ ent
nonwoven fabricsthr ough the needlepunching processwasalso explored. The str ength and
per meability resultsobtained for these fabricswer e promising and consistent for the
intended end-uses. Calender ing wasfound to increase the filtr ation efficiency of the fabrics
by regulating their density and per meability. Asa result, the fibersbecame mor e tightly
packed, thusmaking it mor e difficult for particlesto passthr ough the body of the fabric.
With the incr ease in fabric density, the consolidation of the web incr eased with the
resultant incr ease in dust weight arrestance and dust holding capacity. The resultsin
thisstudy show overall impr ovement of all filtr ation character isticsdue to the calendar ing
operation.

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Developmentsin nonwoven manufactur ing techniques
The utmate in economy in the production of til nonwoven saris from nherenty lowcotrawslie material
converted on sate of the art machinery atthelargetposbesae,opnes RNilclissi--t Narkhedkar,who gves
abreact count of developments in nonwoven manufacturing Ttechniques.
Nonwovensar e fibresin the formof webs, which have to be bonded. Fibr e bonding methods are
generally chemical, ther mal and mechanical. Developmentshave taken place in the
processof manufactur ing a nonwoven such asspun bonding, spun lacing, air laying, cr oss- lapped
nonwovens, for mation of randomnonwoven webswith the static method, needle punching
nonwoven. Due to the continuousresear ch newer nonwoven productshave been developed such
asdevelopment of eco-fr iendly nonwoven productsby soluablisation of viscose, production of
nonwoven fibre board panel and latex foamsheet using coir and polypropylene blends, needle
punched nonwoven blankets, and the ver tical and horizontal type of nonwoven productsfor
automobile interiors.
Development in web for ming process

15. Page9
For ming a randomnonwoven webswith the static method
Thisdevelopment hastaken place for randomfibr e
arrangementsin roller card web processed by differ ent voltagesand electr ode
panel shapes. In thisdevelopment it hasbeen found that by changing shape of electr
ode panel can provide better randomeffectswhen the same voltage is
used. Resear ch indicatesthat the best panel shapesar e the cir cular holesand when positioned
between the cylinder and doffer the optimumr andomeffect isobtained when or iginal panel
iselectr ified to 2 kVbetween cylinder and doffer , or the panel with the cir cular holesiselectrified
with 20 kVand placed over conveyor belts.
Micro feed 2000
It issimilar to dr awframe autoleveller , which hasdeveloped by TathamCompany,
the UK. It isused in the feeding system of car ding to impr ove the quality of car
ded web. Ther e are three transducer sused in thissystem:
One for feed quantity sensing.
Second for changing the feed roller speed.
Thir d for contr olling the taker in speed.
Thispr ocessbecomesver y useful to maintain the unifor mity of web and in manufactur ing hybrid
and composite products.

16. Wet-laid nonwovens
This is a borrowed technology from the paper industry. In this manufacturing
process of nonwoven fibres used are:
0.3 mm–25 mm& 6.0 dtex max. In this process fibres are dispersed and
suspended in water at 0.05%
concentration.
Cross-lapped nonwovens Cross-lapped nonwoven differ sin many ways from
other production process. The main advantage of this development is the
flexibility regarding type of product and weight. Her e the deliver y belt is
doubled, ie, batt of sever al layers are being for med; the card web enters the
lappers with constant speed on the layering carriage to performan oscillating
movement, as the layering carriage reduces its speed during reversal and

17. Page10
isslowed down to zer o and so it leadsto accumulation of fibresin that area.
Air laying nonwovens
The air laying producesfinal batt in one stage without preparing any lightweight web. It is also
capable of running with the higher production speed. The width is3 - 4 m, the degr ee of opening
islesser than the car d and the air laid fabric givesa str ength of 2.5:1 which isdue to the
randomfibre arrangement.
Development in web bonding process Aquajet bonding
Thisisused in the spun lacing process. It isjust similar to needle punching processbut
here water isused instead of metal needles. Water with high-
pressur e around 600 bar , pier cesthe web due to which the fibresget entangled with one
another.

18. Needle loom for nonwoven
In recent years a development has taken place in the manufacturing of needle loom for the
production of needle punched nonwovens, which is having following advantages:
The linear needle path results in better fibre orientation and fibre entanglement than the
conventional needle machine.
Super ior web properties can be obtained with fewer needle preparation.
It greatly enhances the construction of composites and hybrid products.
It leads to increase in productivity.
Different types of nonwovens
1.Advanced cellulosic nonwovens
Conventionally, regenerated cellulosic fibres are used for nonwoven production. Since then,
synthetics have grown to dominate the market. Cotton, for centuries the most important of all
fibres is taking second place to the combined weight of synthetics and viscose rayon.
Rayon now appearsrelegated to little mor e in a global fibre market due to ready availability of
cheap fossil fuelsand the demand for commodity textiles and nonwovens. Then the declining
cost of synthetics coupled with their easy conversion into binder-free spun-laid and melt-blown
fabrics is causing a steady decline in rayon’s nonwoven market share.

19. Page11
The rectangular inser tswith their heat-sealed latex-bonded rayon cover swer e too stable to be
disposed of in the toilet even after tear ing in half. New wet-laid nonwovensmade from the specially
developed self-bonding collapsed-tube rayon fibreshad no wet-str ength at all and disper sed easily in
flowing water . However when treated with the standar d wet-str ength agentsused in the paper industr
y it became str ong enough in use and remained
disintegr ated in toilet turbulence. Rayon producer sin Europe, Japan and the USAdeveloped such
fibresand a small mar ket hasdeveloped in the USA.
2.Lyocell nonwovens
Lyocell makesexcellent nonwovens, especially in those processesthat allowitssuper ior aestheticsshine
through, like needle punching and HE. Itshigh str ength isof little intr insic value in disposables, but
enablesthe nonwoven producer to reduce basisweight while meeting targets. Itsfreedomfr omshr
inkage and high wet stability allowshigher area yields in HE processesand itshigh moduluspr eventsit
fromcollapsing in the wet to the same extent asviscose rayon. Fibr illation, the development of sur
face micr o fibre on wet
abrasion or in high-pressur e entanglement, addsan additional dimension for the nonwoven
development. Unfortunately, while it hasestablished itself in sever al profitable niches, its
premiumpositioning hasso far prevented itsuse in main stream disposables.

20. Spun-laid lyocell nonwovens
Most fibre-forming polymer solution scan also be converted into continuous yarns, film sponges, or
indeed nonwoven fabrics. Lyocell dope is no exception and many of the
Characteristics of the Lyocell process make it a better basis for spun-laid nonwovens than the
viscose process ever was. In nonwoven industry the leading products are nearly always with those
the lowest cost and justification of spun-laid cellulosic on added value alone has failed sever al
times already. The ultimate in economy arises froinherently low cost raw material converted on
state-of-the-art machinery at the largest possible scale. The nonwoven industry enjoys the economies
of polypropylene because PP isa by product of the world’s largest industry. Viscose rayon is the
premium product of the timber industry, which requires the costliest grades of wood pulp. Lyocell is
currently similar , but its simple production process leads to far unexplored potential to use cheaper
pulps. It also has potential to achieve a very high level of scale in textile, and hence the economies
of scale that may ultimately interest the major nonwoven converters.
New development in biodegradable nonwovens
The fibres used have changed from almost exclusively non-biodegradable to most exclusively
biodegradable for the environment among consumer becoming progressively stronger. In fact in the
largest and most potentially environmentally sensitive market, cover stock for disposal diaper s,
biodegradable products are non-existent. An expressed consumer
preference for "environment-friendly" products, in the disposable sarea at least, appears to meet the
needs.

21. Page12
5.Needle punched nonwoven blankets
Tr aditionally woven blanketswer e used in the Far East and Middle East countr ies. These
methodsar e not economical, so a special technique wasdeveloped known asneedle punching.
Thispr ocessconsistsof three min stages:
Pr edator y process.
Web formation.
Needling the fibres web.
The various particulars are as follows:
Var iablesparticulars
Fabr ic weight (g/ sq metr e) 350 Needling density (p/ sq metr e) 250
Depth of penetration (mm) 9
It isobser ved the ther mal insulation value increaseswith increase in the nonwoven bulk density
and needling density. Air per meability value reduceswith incr ease in the nonwoven bulk and
needle density.
Application development foamsubstitution
The objective for resear ch isto develop seat cover swith decor ation and upholster y, which
hasbeen made fromone raw mater ial such aspolyester . Thiscan be removed fromthe seat again
without problemafter shr edding. These componentscan be re-cir culated as
recyclable ther moplastic. Thisisalso valid to the same extent for door side cladding, roof liner
sand, partly also for carpetswher e the pile and backing are the same or can at least be separ ated.

22. Page13
Theultimateineconomyintheproductionofnonwovensarisesfrominherentlylowcostraw
materialconvertedonstate-of-the-artmachineryatthelargestpossiblescale,opinesRN
Narkhedkar,whogivesabriefaccountofdevelopmentsinnonwovenmanufacturing techniques.
Nonwovensar e fibresin the formof webs, which have to be bonded. Fibr e bonding methods are
generally chemical, ther mal and mechanical. Developmentshave taken place in the
processof manufactur ing a nonwoven such asspun bonding, spun lacing, air laying, cr oss- lapped
nonwovens, for mation of randomnonwoven webswith the static method, needle punching nonwoven.
Due to the continuousresear ch newer nonwoven productshave been developed such asdevelopment
of eco-fr iendly nonwoven productsby soluablisation of viscose, production of nonwoven fibre board
panel and latex foamsheet using coir and polypropylene blends, needle punched nonwoven blankets,
and the ver tical and horizontal type of nonwoven productsfor automobile interiors.
Development in web for ming process
Forming a random non woven webs with the static method
Thisdevelopment hastaken place for randomfibr e
arrangementsin roller card web processed by differ ent voltagesand electr ode panel
shapes. In thisdevelopment it hasbeen found that by changing shape of electr ode
panel can provide better randomeffectswhen the same voltage is

23. Page14
used. Resear ch indicatesthat the best panel shapesar e the cir cular holesand when positioned between the cylinder and doffer the
optimumr andomeffect isobtained when or iginal panel iselectr ified to 2 kVbetween cylinder and doffer , or the panel with the cir cular
holesiselectrified with 20 kVand placed over conveyor belts.
Micro feed 2000
It issimilar to dr awframe autoleveller , which hasdeveloped by TathamCompany, the UK. It isused in the feeding
system of car ding to impr ove the quality of car ded web. Ther e are three transducer sused in thissystem:
One for feed quantity sensing.
Second for changing the feed roller speed.
Thir d for contr olling the taker in speed.
Thispr ocessbecomesver y useful to maintain the unifor mity of web and in manufactur ing hybrid and composite products.
Wet-laid nonwovens
Thisisa borrowed technology fromthe paper industr y. In thismanufactur ing processof nonwoven fibresused are:
0.3 mm–25 mm& 6.0 dtex max. In thisprocessfibr esare disper sed and suspended in water at 0.05%
concentration.
Cr oss-lapped nonwovens Cr oss-lapped nonwoven differ sin many waysfr omother
production process. The main advantage of this development isthe flexibility regar ding type of product and
weight. Her e the deliver y belt isdoubled, ie, batt of sever al layersare being for med; the card web enters the
lapperswith constant speed on the layering
car r iage to performan oscillating movement, asthe layering carriage reducesitsspeed dur ing rever sal and
isslowed down to zer o and so it leadsto accumulation of fibresin that area.
Air laying nonwovens
The air laying producesfinal batt in one stage without preparing any lightweight web. It is also capable of running with the higher
production speed. The width is3 - 4 m, the degr ee of

24. opening islesser than the card and the air laid fabric givesa str ength of 2.5:1 which isdue to the randomfibr e arrangement.
Development in web bonding process Aqua jet bonding
Thisisused in the spun lacing process. It isjust similar to needle punching processbut here water isused instead of
metal needles. Water with high-
pressur e around 600 bar , pier cesthe web due to which the fibresget entangled with one another.
Needle loomfor nonwoven
In recent yearsa development hastaken place in the manufactur ing of needle loomfor the production of needle punched
nonwovens, which ishaving following advantages:
The linear needle path resultsin better fibre or ientation and fibre entanglement than the conventional needle
machine.
Super ior web propertiescan be obtained with fewer needle preparation.
It greatly enhancesthe constr uction of compositesand hybrid products.
It leadsto increase in productivity.
Differ ent typesof nonwovens Advanced cellulosic nonwovens
Conventionally, regenerated cellulosic fibresare used for nonwoven production. Since then, syntheticshave grown to dominate
the mar ket. Cotton, for centur iesthe most impor tant of all fibresistaking second place to the combined weight of
syntheticsand viscose rayon.
Rayon nowappearsrelegated to little mor e in a global fibre mar ket due to ready availability of cheap fossil fuelsand the
demand for commodity textilesand nonwovens. Then the declining cost of syntheticscoupled with their easy conver sion
into binder-free spun-laid and melt-blown fabricsiscausing a steady decline in rayon’snonwoven mar ket shar e.
The rectangular inser tswith their heat-sealed latex-bonded rayon cover swer e too stable to be disposed of in the toilet even
after tear ing in half. New wet-laid nonwovensmade from the specially developed self-bonding collapsed-tube rayon fibreshad
no wet-str ength at all and disper sed easily in flowing water . However when treated with the standar d wet-str ength
agentsused in the paper industr y it became str ong enough in use and remained
disintegr ated in toilet turbulence. Rayon producer sin Europe, Japan and the USAdeveloped

25. Page16
Lyocell nonwovens
Lyocell makesexcellent nonwovens, especially in those processesthat allowitssuper ior aestheticsshine through, like needle
punching and HE. Itshigh str ength isof little intr insic value in disposables, but enablesthe nonwoven producer to reduce
basisweight while meeting targets. Itsfreedomfr omshr inkage and high wet stability allowshigher area yields in HE
processesand itshigh moduluspr eventsit fromcollapsing in the wet to the same extent asviscose rayon. Fibr illation, the
development of sur face micr o fibre on wet
abrasion or in high-pressur e entanglement, addsan additional dimension for the nonwoven development. Unfortunately, while
it hasestablished itself in sever al profitable niches, its premiumpositioning hasso far prevented itsuse in main str
eamdisposables.
Spun-laid lyocell nonwovens
Most fibre-for ming polymer solutionscan also be converted into continuousyar ns, film sponges, or indeed nonwoven
fabrics. Lyocell dope isno exception and many of the
character isticsof the Lyocell processmake it a better basisfor spun-laid nonwovensthan the viscose processever was.
In nonwoven industr y the leading productsare nearly alwayswith those the lowest cost and justification of spun-laid
cellulosic on added value alone has failed sever al timesalr eady. The ultimate in economy ar isesfr ominherently low
cost raw mater ial conver ted on state-of-the-ar t machiner y at the largest possible scale. The nonwoven industr y
enjoys the economies of polypropylene because PP isa byproduct of the wor ld’slar gest industr y. Viscose rayon isthe
premium product of the timber industr y, which requiresthe costliest gradesof wood pulp. Lyocell is
currently similar , but itssimple production processleadsto far unexplored potential to use cheaper pulps. It also haspotential to
achieve a very high level of scale in textile, and hence the economiesof scale that may ultimately interest the major nonwoven
converters.
New development in biodegradable nonwovens
The fibresused have changed fromalmost exclusively non-biodegradable to most exclusively biodegr adable for the
environment among consumer becoming progressively str onger. In fact in the largest and most potentially environmentally
sensitive mar ket, cover stock for disposal diaper s, biodegr adable productsare non-existent. An expressed consumer
preference for "environment-fr iendly" products, in the disposablesar ea at least, appears to meet the needs.
Needle punched nonwoven blankets
Tr aditionally woven blanketswer e used in the Far East and Middle East countr ies. These methodsar e not economical, so a
special technique wasdeveloped known asneedle punching. Thispr ocessconsistsof three min stages:

26. Page17
Pr edator y process.
Web for mation.
Needling the fibresweb.
The various particulars are as follows:
Var iablesparticulars
Fabr ic weight (g/ sq metr e) 350 Needling density (p/ sq metr e) 250
Depth of penetration (mm) 9
It isobser ved the ther mal insulation value increaseswith increase in the nonwoven bulk density and
needling density. Air per meability value reduceswith incr ease in the nonwoven bulk and needle
density.
Application development foamsubstitution
The objective for resear ch isto develop seat cover swith decor ation and upholster y, which hasbeen
made fromone raw mater ial such aspolyester . Thiscan be removed fromthe seat again without
problemafter shr edding. These componentscan be re-cir culated as
recyclable ther moplastic. Thisisalso valid to the same extent for door side cladding, roof liner sand,
partly also for carpetswher e the pile and backing are the same or can at least be separ ated.

27. Page18
jbxc
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1. Asian Textile Jour nal, August TextileTrends, March 2001.
2. Asian Textile Jour nal, May2000.
3. Textile World,Nov2003
4. Man-made Textilesin India, July2001.
5. Melliand International, Sept2000.
6. Melliand International, Sept2001.
7. Textile World,Feb2004.
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ASTMD737-96, 1997 Annual Book of ASTMStandar ds, Vol. 7.01, ASTM, West Conshohocken, PA, U.S.A. (1997).
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ASTM, West Conshohocken, PA, U.S.A. (1998).
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(1958).
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6] Docker y A. (1995), ‘Spandex Movesin the Fast Lane’, Amer ica’sTextilesInter national, 227, September . 15 Str ipe
M. (1996), ‘Lycr a Technological Renaissance Beginswith Introduction of Lycr a Soft’, Knitting Times, 57, May.
7] McCur ry J. W. and IsaacsM. (1996), ‘Str etch, Dur ability and Style among Fiber Tr ends’, Textile Wor ld, 39–46,
August.
8] Anon. (1992), ‘DuPont DevelopsWaste-fr ee Route to Ter athane’, Chemical Week, 9, October 14.
9] Anon. (1994), ‘DuPont CompletesPTMEG Pr ocessTr ial’, Chemical Week, 16, Januar y 5/ 12. [ 10] EvansB. A.,
Boleslawski L. and Boliek J. E. (1997), ‘Cotton Hosier y Bleaching with
Hydr ogen Per oxide’, Textile Chemistsand Color ist, Vol. 29, No. 3, 28. AUTHORS’ADDRESSES Sakthivel S. Ezhil
Anban J.J. Angel College of Engineering and Technology P.K Palayam Dhar apuramMain Road Tir upur, Tamil Nadu
641665 INDIARamachandr an T. Kar pagam Institute of Technology Coimbator e, Tamil Nadu INDIAView publication
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