Spinning

The conservation of polymer into fiber is called spinning. Spinning is three types. They are,

1. Melt spinning (Nylon, Polyester, Olefin, and Saran).
2. Wet spinning (Rayon, PVA, and Acrylic).
3. Dry spinning (Acetate, Modacrylic).

Melt spinning:

1. Method into auto clave.
2. Spun into air.
3. Solidifies on cooling.

Special feature of melt spinning:

1. Investment cost low.
2. Hazard- no toxic.
3. Heat of spun is high.
4. Spinning speed is about 2500ft/min.

Flow Chart of Melt Spinning:

1. Feed
2. Melting
3. Metiered extrusion
4. Cooling and solidification by cold air.
5. Moisture conditioning.
6. Lubrication.
7. Yarn packaging.

Requirements:

1. The polymer should not volatile.
2. The melting point of polymer should be 30ºC less than its decomposition temp.

Advantage:

1. Can be used bath staple and continuous filament.
2. No environment pollution.
3. High production speed.

Disadvantage:

1. Required more maintenance of the machine.
2. Heat of input is high.

Typical melt spinning:

Polymer	Melting point (ºC)
Nylon 6,6	264
Nylon 6	220
Polyester	264
Polyethylene	125

Wet spinning:

1. Dissolve by chemical.
2. Spun into acid bath.
3. Solidifies when coagulated by acid.

Special feature of wet spinning:

1. Investment cost is low.
2. Hazard- no toxic.
3. Heat of spun is low.
4. Spinning speed is about 150/300ft/min.

Dry spinning:

1. Dissolve by solvent.
2. Spun into warm air.
3. Solidifies by evaporation.

Special feature of dry spinning:

1. Investment cost is high.
2. Hazard- toxic.
3. Heat of spun is very high.
4. Spinning speed is 2500 to 3000ft/min.