Polyester Fiber

Polyester is a class of polymers which accommodate the ester anatomic accumulation in their capital chain. Although there are abounding polyesters, the appellation “polyester” as a specific actual a lot of frequently refers to polyethylene terephthalate (PET).

Fiber manufacturing process:

Today over 70 to 75% of polyester is produced by CP (continuous polymerization) process using PTA (purified Terephthalic Acid) and MEG. The old process is called Batch process using DMT (Dimethyle Terephthalate) and MEG (Mono Ethylene Glycol).

Sequence of Man-Made Fiber production:

Manufacture of Fiber forming polymer

1.Spinning

2.Stretching & Drawing

3.Texturing or Crimping

4.Interlacing or Intermingling

5.Heat setting

Physical & chemical properties of polyester Fiber:

• Denier: 0.5 – 15
• Tenacity : dry 3.5 – 7.0 &  wet 3.5 – 7.0
• %Elongation at break : dry 15 – 45 & wet 15 45
• %Moisture regain : 0.4
• Shrinkage in boiling water : 0 – 3
• Crimps per inch : 12 -14
• %Dry heat shrinkage : 5 – 8 (at 180 C for 20 min)
• Specific gravity : 1.36 – 1.41
• % Elastic recovery; @2% =98 : @5% = 65
• Glass transition temp : 80⁰ C
• Softening temp : 230 – 240⁰ C
• Melting point : 260 – 270 ⁰ C
• Effect of Sunlight : turns yellow, retains 70 – 80 % tenacity at long exposure
• Resistance to weathering:  good
• Rot resistance: high
• Alkali resistance : damaged by CON alkali
• Acid resistance : excellent
• Organic chemical resistance : good

Lustre:

Polyester Fibers are available in

bright : 0.05 to 0.10 % TiO2

Semil dull: 0.2 to 0.3 % TiO2

dull : 0.5 % TiO2

extra dull : 0.7% TiO2

Properties required for Fiber forming polymer:

• Molecular weight should be high.
• Medium crystallinity.
• Resistance to deferent chemicals.
• Orientation; Following are suitable
• T_g should be near to room temperature.
• T_m = 200 to 300⁰C
• Hygroscopic nature should be hydrophilic.
• Polymer should be soluble in some solvent form which it can be spun.

Polyester Fiber Uses

• Apparel:Making sewing thread, bland with cotton fiber when making fabric.
• Home Furnishings:Carpets, curtains, draperies, sheets and pillow cases, wall coverings, and upholstery.
• Other Uses: hoses, power belting, ropes and nets, thread, tire cord, auto upholstery, sails, floppy disk liners, and fiberfill for various products including pillows and furniture

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