Man Made Fiber Spinning

Prepared By : Mazadul Hasan sheshir
ID: 2010000400008
13th Batch (session 2009-2013)
Department : Wet Processing Technology
Email: mazadulhasan@yahoo.com
Blog : www. Textilelab.blogspot.com (visit)
Southeast University
Department Of Textile Engineering
I/A 251,252 Tejgaon Dhaka Bangladesh
Prepared By :
©right

Calssificatoin of fibres

Forms of Man Made fibre:
MMF are produced in three types –
1. Filament:Filament fibres are spun from
spinnerets with 350 holes or less is determined
by the size of the yarn to be made
Monofilament: This filament is made only of a
single filament.
Multifilament: These filaments are made of
more than one filament.
2. Staple:Staple fibre is of limited and relatively
short length
3. Filament tow. An assemble of twist free fibre.

Properties required for Fibre forming polymer:
•Molecular weight should be high.
•Crystallinity – high not suitable.
•Resistance to different chemical.
•Orientation – Physical and chemical symmetry.
•Straight chain structure.
•Glass Transition Temperature (Tg) – Should be near
to Room Temp.
•Crystalline Melting Point (Tm) - 200o – 300o c is
suitable.
•Polymer should be soluble in some solvent from
which it can be spun.
•Hygroscopic nature – Should be hydrophobic

Synthetic Spinning System

• Spinneret: A nozzle or plate provided with fire holes
or slits through a fibre forming solution or melt is
extruded in fibre manufacturing is called spinneret.
This is the most important part of a MMF producing
m/c. The number of holes, sizes and shapes vary
with the filament desired.
• Shape of holes:
Spinneret

Features of Spinneret:
Spinneret length: 10-25 mm
Spinneret diameter: 30-200 mm
Spinneret thickness: 3.0 mm
Hole dia: 0.1.-0.8 mm
Problems:
-Breaking (On account of high pressure and temp)
Clogging (The holes can be blocked for solid particles
mix with polymer solution).
Remedies:
-For breaking problem: the spinneret is to be changed.
-For clogging: the spinneret should be cleaned after
some days.

Number of holes in spinneret:
1. For monofilament:1-3
2. For multifilament: 100-1000
3. Filament tow: up to 50,000

Flow chart of MMF production:
1. Manufacture of the fibre forming polymer.
2. Spinning ( extrusion through spinneret)
3. Stretching/Drawing ( improving strength and crystallinity)
4. Texturing/Crimping ( developing natural fibre properties)
5. Intermingling/Interlacing( applied instead of twisting)
6. Heat setting( made dimensionally stable)
7. Cutting: According to requirements.

1. Manufacturing of the fibre forming polymer:
• All man made fibres are composed of long
chain molecules known as polymer which are
formed by chemical processing.
• Common groups in polymers –
– Amide or Peptide groups ( -CO-NH-)
– Benzene ring
– Ether linkage( -C-O-C-)
– Ester linkage(-C-O-O-)
– Hydroxyl group (-OH)
– Nitrile group (-C-N-)

Spinning:
• The conversion of polymer into fibre is called
spinning. The fibre forming substance is made
temporarily fluid, extruded through spinneret
and then returned to solid state (by
solidification) in fibre form.
• Three types of spinning process:
– Melt spinning (Synthetic).
– Wet spinning.
– Dry spinning.

SPINNING of polymers
There are typically three types of spinning for polymers: Melt, Dry and Wet.
▪ Melt spinning (Fig. 1) is used for polymers that can be melted easily.
▪ Dry spinning (Fig. 2) involves dissolving the polymer into a solution that can
be evaporated.
▪ Wet spinning (Fig. 3) is used when the solvent cannot be evaporated and
must be removed by chemical means.
Melt spinning
In melt spinning the fibre-forming material is melted and extruded through
spinnerets, and the jets harden into solid filaments as they cool on emerging from the
spinneret. Nylon is a melt-spun fibre.
Dry spinning
In dry spinning the fibre-forming substance is dissolved in a solvent before the
solution is extruded. As the jets of solution emerge from the spinneret, a stream of
hot air causes the solvent to evaporate from the spinning solution, leaving solid
filaments. Acetate is dry spun by extruding acetone solutions of cellulose acetate into
hot air.
Wet spinning
In wet spinning the solution of fibre-forming material is extruded into a coagulating
bath that causes the jets to harden as a result of chemical or physical change.
Viscose, for example, is wet spun. The solution of cellulose xanthate is extruded into
an aqueous solution of acids and salts, in which the cellulose is regenerated to form
solid filaments.
Man Made Fiber Spinning Technology

Man Made Fiber Spinning Technology

02. Spinning: Melt spinning:
• The process of spinning by which fibre or
filament is produced from melted polymer
chips by extruding through spinneret
continuous filament produced here.
• Number of filament depends on number of
holes in spinneret.
• It is the most critical operation in the
production of nylon polyester, and polyolefin,
poly propylene fibres as number of fibre
properties such as uniformity, crystallinity, and
orientation are imparted to the yarn during
processing.

02. Spinning: Melt spinning:
• .Feed
Melting
Cooling &
solidification by
cold air.
Moisture
conditioning
Lubrication
Yarn driving
Packaging
Flow Chart
Metered extrusion

02. Spinning: Melt spinning:
Advantage:
– Can be used for both staple and continuous
filament.
– Direct and simple process.
– No environment pollution.
– No solvent required.
– Non toxicity and no risk of explosion.
– High production speed (2500 – 3000 ft/min)
– Low investment cost.
• Disadvantage:
– Required more proper maintenance of the m/c.
– Heat of input is high.

02. Spinning: Melt spinning:
Typical melt spinning:
Polymer Melting point
Nylon – 6, 6 264oC
Nylon – 6 220oC
PET 264oC
Polypropylene 167oC
Poly ethylene 125oC

02. Spinning: Dry spinning:
• In dry spgn, the fibre forming polymer dissolved
in a volatile solvent is introduced into a heated
drying chamber where the solvent is
evaporated and solid fibre is obtained through
spinneret.
• This process is used for Acetate and some
polyacrylonitrile fibre.

02. Spinning: Dry spinning:
• Dry spinning solvent:
Fibre Solvent
I) Cellulose -Acetone + (2-6) % water
II) II) Triacetate -Methylene chloride (40%)
+ Methanol (10%)
III) Poly acrylonitrile -Di-methyl formamide or
Dimethyl acetamide.
IV) Spandex - DMF, DMAC.
V) Modacrylic - Acetone.

02. Spinning: Dry spinning:
• . Feed
Metered extrusion
Solidification by solvent
Evaporation
Lubrication
Yarn driving
Packaging

Dry spinning Process

Dry spinning Process

02. Spinning: Dry spinning:
• Advantage:
– Suitable for producing fine denier fibres.
– No need of wash of fibre.
• Disadvantage:
– Investment cost is high.
– Toxic and risk of explosion.
– Heat input is very high.
– Can not be used for staple fibre production.
• Properties of solvent:
– Solvent should not be volatile.
– It should be organic.
– It should have low boiling point.
– It should be comparatively cheap.
– It should be thermally stabilized.
– It should be non toxic.

02. Spinning: Wet spinning:
• In wet spinning a suitable solvent is used to prepare
fibre forming solution and another coagulant is used
in coagulating bath.
• Solution is extruded through spinneret and in contact
of coagulant cellulose is regenerated.
• Wet spgn solvent & coagulant:
Fibre Solvent Coagulant
Viscose Alkaline water Dill H2SO4 + Na2SO4 +ZnSO4
PVA Water Aqueous NaOH
PAN DMF/DMC + Aq DMF/DMC + 40% ZnCl2
• 60% ZnCl2

02. Spinning: Wet spinning:
Coagulation bath Washing Bath

02. Spinning: Wet spinning:

02. Spinning: Wet spinning:
• Advantage:
– Suitable for staple fibre.
– Both organic and inorganic solvent can be used.
– Low temp reqd.
– Higher production due to continue spgn.
– Softener process.
– Investment cost is low.
• Disadvantage:
– Slow spgn speed.
– Washing and bleaching of fibres are needed.
– Toxic.

02. Spinning: Difference
Parameter Melt spgn Dry spgn Wet spgn
1. Investment cost Low High Low
2. Hazard Non toxic Toxic Toxic
3. Heat of spgn High Very high Low
4. Spinneret hole 2 – many
thousands
300 – 900 20000 – 75000
5. Spgn speed 2500 – 3000
ft/min
2500 – 3000
ft/min
150 – 300 ft/min
6. Productivity High Low High
7. Application Filament or
staple
Filament Filament or
staple
8. Solvent Not required Only volatile
organic solvent
Both organic and
inorganic solvent
can be use.

Features Melt Dry Wet
Investment Cost Low High Low
Hazard Non-toxic
Toxic
(Risk of
explosion)
Toxic
Heat of Spinning High High Low
Spinneret Hole
2 to many
thousand
300-900 20,000-75,000
Spinning Speed 2500-3000
ft/min
2500-3000
ft/min
150-300 ft/min
Comparative features of melt, dry and wet spinning

•Production does not depend on climate & location.
•Quality & quantity can be controlled during production.
•Length & thickness can be controlled as per requirement.
•Staple length can be controlled as per requirement.
•Smoothness and high luster.
•Fiber processing is easier.
•High productivity and low cost.
Advantage of man-made fiber technology:

1. Fabrics made of MMF are difficult to stitch.
2. Low air permeability.
3. Uncomfortable.
4. Unhygienic.
5. Hydrophobic.
Disadvantage of man-made fiber technology:

1. Yarn Manufacturing Technology
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