prduction technology of man-made fibers

Presentation

ON

The Production Technology Of

Man-Made Fibers

Md. Yousuf Hossain, Green University Of Bangladesh, [email protected]

Md. Yousuf Hossain.

ID No. : 120103063

Department Of Textile Engineering

Green University Of Bangladesh


e.g. : 1. Rayon (Wood/ Bamboo)

2. Polyester (Petrochemicals)


Classification flowchart of man-made fibers

Man-Made Fibres

Inorganic

By transformation of natural polymer

From synthetic polymer

Acrylic = PAN

Aramid = AR

Chlorofiber =CLF

Elastane = EL

Elastolefin = EOL

Elastodiene = ED

Elastomultiester =

EME

Polyamide = PA

Polyester = PES

Polyethylene =PE

Polyimide = PI

Polylactide = PLA

Polypropylene = PP

Vinylal = PVAL

Fluorofiber = PTFE

Modacrylic = MAC

Carbon = CF

Ceramic = CEF

Glass = GF

Metal = MTF

Aliginate =ALG

Acetate = CA

Cupro = CUP

Lyocell = CLY

Modal = CMD

Viscose = CV

Triacetate =CTA

Elastodiene =ED


How can we get man-made fibers?

Man-made fibers are produced from polymers.

These substances are solids at normal temperatures in the form

of chips or small particles.

The polymers in solid form must be converted to fluid form as

the polymer needs to be forced through the spinneret holes to

form filaments.

Solidify fibers by cooling or evaporation or coagulation.


The polymer processing from the solid to the fluid state can

take place with two methods-

I. By Melting. (This method is used for 70% of the fibers)

II. By Solution. (This method is used for 30% of the fibers)

i. Dry Spinning

ii. Wet Spinning

iii. Gel Spinning

The method is used for each fiber depends upon the easy

conversion process of the polymer from solid to fluid state.


Melt Spinning:

The polymer is melted and pumped through a spinneret with

numerous holes (one to thousands). The molten fibers are cooled,

solidified, and collected on a take-up wheel.

Polymer converted to fluid just by heating.

Simplest process used for Polyester, Polyamide, Polyethylene,

Polypropylene and Glass fibers.

High Speed ( up to 10000 m/min)


Required characteristics of fiber for Melt Spinning:

Fibers must melt without decomposition and be stable to at

least 30 degree higher than its melting temperature.

Mobility in the molten polymer is necessary to be

extruded.


Stages in Melt Spinning Process

At first, Heat the polymer.

Then, Extrusion through the spinneret (50mm in diameter) having fine holes of 0.5mm diameter.

Cool and solidify the filament.

Then, the solidified filaments are passed around a rotating roller and forwarded to a collecting roller.

Features Of Melt Spinning:

Melt-spun fibers can be forced through the spinneret in different

cross-sectional shapes such as round, tribal etc. Which give

different qualities to the fabric.

Do not have toxic hazard.

No solvent and purification problem.

The Production Technology Of Man-Made Fibers


Figure 1 : Melt Spinning

Dry Spinning

If Polymer is getting chemically damaged by heating but it

can be dissolved in a suitable volatile solvent which later

on evaporates.

The Production Technology Of Man-Made Fibers

Speed = 1000 m/min.

Used for production of Acrylic, Modacrylic, Acetate, Triacetate,

Spandex/Elastane.


Merits Of Dry Spinning:

Yarn does not required purification.

Demerits Of Dry Spinning:

The obvious limitation for this method is that it depends on the

existence of volatile solvent for the polymer.

Solvents are expensive, flammable and explosive in reaction

with air.

3-6 kg solvent is needed for 1kg filament.


Wet Spinning

If the polymers cannot be melted by heating or dissolved in

volatile solvent then wet spinning is used.

The spinneret is submerged in a chemical bath that leads the

fiber to precipitate and solidify as it comes out of the spinneret

hole.

Polymer is dissolved in a non-volatile solvent.

This is a slow process (speed=200 m/min)

Used for production of Viscose, Modal, Lyocell, Aramid fibers. Md. Yousuf Hossain, Green University Of Bangladesh, [email protected]

Figure 3 : Wet Spinning Process

Merits Of Wet Spinning:

Suitable for tow production.

Demerits Of Wet Spinning:

Cumbersome technology.

Purification of the filaments is needed.

Environment pollution hazards.


Gel Spinning:

In gel spinning the filaments first pass through air and then are

cooled further in a liquid bath. Here polymer is partially liquid or

in a gel state, which keeps the polymer chains somewhat bound

together leading to greater tensile strength.

Used for production of high strength PE and aramid fibers.


Figure 4 : Gel spinning process.

Advantages of Gel spinning:

Medium speed (up to 1500 m/min).

Suitable for liquid crystalline polymers.

Disadvantages of Gel Spinning:

Environmental pollution hazards.

Purification of the filament is needed.

Cumbersome technology.


Comparative features of Melt, Dry and Wet Spinning

Features Melt Dry Wet

Investment Cost Low High Low

Toxic Hazard Non-toxic Toxic &

Risk of explosion

Toxic

Heat of Spinning High High Low

Spinneret Hole Two to thousand 300 - 900 20,000 - 75,000

Spinning Speed 1500 - 6000 m/min 1000 - 1500 m/min 200 - 300 m/min


Manmade fibers can be modified at any stage-

During production- e.g. Additives (Delustrant, heat &

light stabilizers)

Immediately after production. e.g. Spin Finish

(Lubricants, plasticizers)


Any Question?

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prduction technology of man-made fibers

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