Why Polyester POY have such a craze in Indian Ethnic Wear

Polyester POY

POY / PFY is largely used in shirtings and suitings, sarees, ladies’ dress material, and knitwear. It is preferred in men’s wear due to its higher crease recovery, wrinkle resistance, better drape, longer retention of prints and colours, and better abrasion as compared with competing fibres, such as PSF, VSF and NFY. 

The use of POY / PFY in sarees has increased due to the development of crimping, twisting, texturising and wet processing technologies. These technologies offer more flexibility in designs and patterns. Moreover, these technologies help increase the air permeability of these yarns. As a result, the fabric would be able to absorb more moisture. 

It is also used in applications, such as soft luggage and specialty fabrics. POY is sold by producers to the texturising units. The texturising units process it and sell it to weavers (largely in the powerloom sector). Unlike PSF, PFY is not blended with cotton by blended yarn producers, since it is in the filament form and not in the fiber form. However, in the powerloom stage, PFY can be woven with other yarns. 

POY / PFY is a substitute for cotton and other synthetic yarns. POY / PFY has a number of advantages over its substitutes. 

These advantages include:

 Better Properties: POY / PFY is more durable, does not fade on exposure to sunlight or soap, has better abrasion resistance, drape and crease recovery properties, and is wrinkle resistant

 Price Competitiveness: Since the 1990s, POY prices have declined significantly, largely due to the decline in the landed costs, on account of decline in the import duty

FULLY DRAWN YARNS

Normal Partially Oriented Yarn (POY) needs to be necessarily texturised before being used for making fabric whereas FDY, as the name of the yarn itself indicates, is drawn fully during the process of spinning itself and therefore does away with the requirement of texturising and can use directly for making fabric.

FDY is generally used for better quality fabric. As the process of texturising is avoided, FDY yields higher contribution as compared to the normal POY.

The following are the properties incorporated during texturing of FDY:

Low Intermingle Yarn

These  are comprised of high modules mono filaments. The range is highly popular because the entanglement spacings in these yarns are relatively low and the tenacity remains relatively unaffected.

Non Internmingle Yarn

Non Intermingle Yarn is known for their minimal entanglement spacings and hence it facilitates easy use.

High Intermingle Yarn

These yarns are commonly used for making fabrics. The range can be availed in different Deniers depending upon the requirements of the clients.

Technical Specifications of Some Popular Synthetic Fabrics-1

Here are the technical specifications of some of the popular synthetic fabrics used in India for Ethnic wear.

Poonam

Warp is a combination of 62/36/1770-"S" Semi dull crimp polyester and 62/36/1880-"Z" semi dull crimp Polyester(2 x2). Here 62 is the denier, 36 is the number of filaments and 1770 is the no of twists per meter.

Weft is the same as warp.

Total number of ends are 3840 in a reed space of 51 inches with a reed and pick of (72 x2) x 68. In a 100 meter cloth the weight of warp is 3.1 kg and that of weft is 2.5 kg to make a total of 5.6 kg of cloth.

Dani Chiffon

Warp is a combination of 20/6/1400 full dull Nylon "S" and "Z" and weft is the same as warp.

Total number of ends are 4080 in a reed space of 40 inches with a reed and pick of (96 x2) x 80. In a 100 meter cloth the weight of warp is 1.05 kg and that of weft is 0.75 kg to make a total of 1.8 kg of cloth.

Poonam Dani Chiffon

A popular fabric for dupatta is Poonam Dani Chiffon. It is a 100% polyester in plain weave. Warp is a combination of filament polyester yarn 75/36 denier twist 1800/S and 75/36 denier with 1800 TPM in Z direction. Weft is Filament polyester yarn with 75/36 denier twist is 1800/S and 75/36 denier with a twist of 1800/Z. It has a general width of 113 cm and a finished weight of 65 GSM.

Ideal tensile strength by grab test method for this fabric is 13.2 Kg for warp and 19.6 kg for weft. Tear strength with KMI tester is 3520 grams for warp and 3392 grams for weft.

It should have a rating of 5 in colorfastness to sunlight, washing, crocking, heat press and perspiration. Dimensional stability should have a tolerance of 2% after 3 cycle. Bow/Skew should be within 2%. It should have a rating of 5 in shade change and pilling under an abrasion testing of 10000 cycles. Length wise washing shrinkage should be 2% and width wise 1% maximum

100 x 100 Georgette

Warp is a combination of 100/44/1770 Viscose "S" and "Z", Weft is same as warp.

Total number of ends are 3276 in a reed space of 50 inches with a reed and pick of (64 x2) x 60. In a 100 meter cloth the weight of warp is 4.3 kg and that of weft is 3.6 kg to make a total of 7.9 kg of cloth.

Marble Chiffon

Warp is a combination of 50/48/2800-"S" of Semi Dull flat Poly and Weft is a combination of 50/48/3025 Z semi dull flat poly yarn. 

Total number of ends are 4600 in a reed space of 58 inches with a reed and pick of (76 x2) x 76. In a 100 meter cloth the weight of warp is 3.1 kg and that of weft is 3 kg to make a total of 6.1 kg of cloth.

China Yoryu Saree

Warp is a combination of 50/36 Bright flat Poly Sized and Weft is a combination of 50/36 Bright flat Poly Sized yarn.

Total number of ends are 6000 in a reed space of 59 inches with a reed and pick of (100 x2) x 80. In a 100 meter cloth the weight of warp is 3.9 kg and that of weft is 2.9 kg to make a total of 6.8 kg of cloth.

Fiber Identification - Burning Test- Man-made Fibers

Viscose Rayon 

All viscose including High Wet Modulus scorch and ignite quickly when brought near the flame. Like cotton they burn quickly with yellow flame when in the flame. When removed from the flame they continue to burn. There is no afterglow unlike cotton. The smell is that of burning paper. They leave a light gray and feathery ash.

Acetate Rayon  ( And Triacetate Rayon)

When brought near the flame, it fuses away from flame turning black. When in the flame, it flames quickly. The fabric puckers, sputters and melts. It drips like burning tar. When removed from the flame, it continues to burn and melt. It smells like vinegar. It leaves a brittle hard, irregular black ash which is difficult to crush.

Nylon 

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Nylon fuses and shrinks away from the flame when brought near the flame. In flame, it burns slowly without melting. When removed from flame the flame diminishes and tends to die out. It has somewhat pungent odor. It leaves a hard, round, tough and gray bead.

Aramid  ( Nomex)

When brought near the flame, it shrinks away from the flame. When in the flames it puckers and chars. When removed from flame, it extinguishes by itself. It has no smell and it leaves a hard black bead.

Polyester  

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Polyester fuses and shrinks away from flame. When in flame, it burns slowly with melting. When removed from the flame, it burns with difficulty. It has slightly sweetish smell. It leaves a hard round brittle, black bead.

Acrylics 

Orlon, Acrilan and Creslan and Zefran fuse and melt away from Flame when brought near the flame. When in flame Orlon flames rapidly. The fiber puckers, sputters and melts. Acrilan flames rapidly and melts. Creslan flames and melts and Zefran sputters slightly and flames. When removed flame all of acrylics continue to burn and melt. Orlon has a slightly burning meat-like smell. Acrilan has a buring steak smell. Creslan has sharp sweet smell and Zefran has a turmeric like smell. Orlon, Acrilan and Cresla have hard, brittle and irregular black bead. Zefran has irregular black ash that can be crushed easily.

Modacrylics

Verel and SEF fuse and shrink away from the flame when approached near a flame. When in flame, Verel burns very slowly with melting. SEF shrinks, melts and smolders. When removed from flames, all modacrylics are self extinguishing. Verel has a gunpower smell whereas SEF has a sharp sweet smell. Verel leaves a hard and irregular black bead whereas SEF leaves a hard and irregular black bead.

Spandax 

Fuses but doesn’t shrinks away from the flame when approached near the flame. When in flame, it burns with melting. It has an acrid smell. It leaves a soft, fluffy black bead.

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Properties of Polyester

Tenacity (gpd)	High Tenacity	Normal Tenacity	Staple
Dry	6-7	4.5-5.5	3.5-4
Wet	6-7	4.5-5.5	3.5-4
Elongation (%)
Dry	12.5-7.5	25-15	40-25
Wet	12.5-7.5	25-15	40-25
Density	1.38	1.38	1.38

Moisture Regain

At 65% RH and 70 deg F--> 0.4%

Because of low moisture regain, it develops static charge. Garments of polyester fibres get soiled easily during wear.

Thermal Properties

Polyester fibres are most thermally stable of all synthetic fibres. As with all thermoplastic fibres, its tenacity decreases and elongation increases with rise in temperature. When ignited, polyester fibre burns with difficulty.

Shrinkage

Polyester shrinks approx 7% when immersed in an unrestrained state in boiling water. Like other textile fibres, polyester fibres undergo degradation when exposed to sunlight.

Its biological resistance is good as it is not a nutrient for microorganisms.

Swelling and Dissolving

The fibre swells in 2% solution of benzoic acid, salycylic acid and phenol.

Alcohols, Ketones, soaps, detergents and drycleaning solvents have no chemical action on polyester fibres.

Chemical Resistance

Polyester fibres have a high resistance to organic and mineral acids. Weak acids do not harm even at boil. Similarly strong acids including hydrofluoric acids do not attack the fibres appreciably in the cold.

Uses of Polyester

1. Woven and Knitted Fabrics, especially blends.
2. Conveyor belts, tyre cords, tarpaulines etc.
3. For filling pillows
4. For paper making machine
5. Insulating tapes
6. Hose pipe with rubber or PVC
7. Ropes, fish netting and sail cloth.

Manufacturing Process of Polyester

Manufacture of Polyester

These fibres are also known as Terylene, Terene, Dacron etc.

These fibres are synthetic textile fibres of high polymers which are obtained by esterification of dicarboxylic acids, with glycols or by ester exchange reactions between dicarboxylic acid esters and glycols.

Thus Terylene is made by polymerising using ester exchange reation between dimethyl teraphthlate and ethylene glycol.

Raw Materials

The main raw materials required for the manufacture of Terylene polyester fibres are p-xylene ethylene glycol and methanol.

or Dacron ( Du Pont ) is produced by polycondensation reaction using Teraphthaleic Acid (TPA) and Ethylene Glocol

Manufacture of TPA

P-xylene-- Air, nitric Acid-->P-Toluic Acid--> Teraphthaleic Acid

Manufacture of DMT

p-xylene--Air 200 degC, co-toluate--> Toluic Acid--Ch3OH--> Monomethyl toluate--oxidation--> Monomethyl teraphthalate--CH3OH--> DMT

The use of Dimethyl Teraphthalate is preferred instead of Teraphthalic acid as the purity of the reacting chemicals is essential and it is easier to purify DMT than teraphthalic acid.

Manufacture of Ethylene Glycol

Ethylene--Oxidation with air-->Ethylene Oxide--Hydrolysis-->Ethylene Glycol
or
Ethylene--Hypochlorous Acid HOCl--> Ethylene Chlorohydrin--Alkaline Hydrolysis--> Ethylene Glycol

Production


The polymer is made by heating teraphthalic acid with excess of ethylene glycol ( Both of high priority) in an atmosphere of nitrogen initially at atmospheric pressure. A catalyst like hydrochloric acid speeds up the reaction.

The resulting low molecular weight ethylene glycol teraphthalate is then heated at 280 deg C for 30 minutes at atmospheric pressure and then for 10 hours under vacuum. The excess of ethylene glycol is distilled off. the ester can polymerise now to form a product of high molecular weight. The resulting polymer is hard and almost white substance, melting at 256 deg C and has a molecular weight of 8000-10000. Filaments are prepared from this.

Spinning of Polyester Fibres

The polymer is extruded in the form of a ribbon. This ribbon is then converted into chips.

The wet chips are dried and fed through a hopper, ready for melting. This molten polymer is then extruded under high pressure through spinnerettes down to cylinder.

Each spinnerette contains 24 or so holes. A spinning finish is applied at this stage as a lubricant and an antistatic agent. The undrawn yarn is then wound onto cylinders.

This yarn goes to the drawing zone, where draw twist machines draw it to about four times their original length. This is hot drawn in contrast to cold drawing of nylon filaments.

For the production of staple fibres, the filaments are first brought together to from a thick tow. These are distributed in large cans. The tow is drawn to get correct strength. Then it is passed through a crimping machines, the crimps being stabilized by heating in ovens. It is then cut into specified lengths and baled ready for despatch.

Dyeing of polyester with indigo

Please see the following link for dyeing of polyester with indigo.