In the total fiber consumption market the polyester share was 52% compare to other natural and chemical fiber where cotton share was 24.2% in 2020, according to the latest data of statista. Out of the total consumption of 52 % polyester fibre Spun Polyester Share is 18% and Filament Polyester share is 34 %. The data depicts that Filament Polyester fibre share is more than Cotton share in Global Fiber Consumption.
Interestingly, in Bangladesh there are around 400 cotton spinning mills whereas numbers of filament spinning mills are only 5. So, we can say that another 100 mills of polyester filament can easily survive in Bangladesh, once it meets the quality and price of the international market. At present, Bangladesh imports more than 10 million tons of polyester per year from China, Thailand, Indonesia and India.
Polyester yarn classification: There are mainly 2 types of polyester yarn. One is spun polyester and another is filament polyester. The filament polyester is different form POY, DTY, ACY. FDY SCY, ATY etc. Polyester yarn count is normally mentioned by Denier.
- POY: It is also known as Polyester Partially-Oriented Yarn. It is the first form of yarnmade directly from PTA & MEG or by spinning Polyester PET Chips/Flakes. POY is mainly used in texturizing to make textured yarn, also known as Polyester Drawn Textured Yarn (DTY).
- DTY: Draw textured yarn(DTY) is made from Partially Oriented Yarn (POY). When the POY is drawn and twisted at the same time, the end product obtained is a draw textured yarn. The technical specifications of draw textured yarn have made it ideal for a wide range of applications as it can be molded in several ways as well.
- ACY: Air covered yarnis manufactured by interlacing Spandex yarn with Nylon/Polyester by the help of compressed air. Spandex is then applied during a draw texturizing process of Polyester or Nylon to avoid the additional process of spandex application.
- FDY: Fully Drawn Yarn(FDY) is produced by a process similar to POY manufacturing except that the yarn is produced at higher spinning speeds coupled with intermediate drawing integrated in the process itself. This allows stabilization through orientation and crystallization.
- Denier: Denieris a unit of measurement used to determine the fiber thickness of individual threads or filaments used in the creation of textiles and fabrics. Fabrics with a high denier count tend to be thick, sturdy, and durable.
What is melt spinning?
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Melt spinning is a manufacturing process used to produce polymeric or synthetic fibers. It utilizes a rapid cooling system to transform melted base materials into long strands, filaments. Melt spinning is commonly used to produce fibers such as Nylon, Polyester and Acrylic.
In a typical melt spinning application, the manufacturing process is performed on a large spinning tower. A drum of melted polymers sits at the top of the tower, with a pump and filtering system situated below. The pump directs melted Polymer down through a metal die (Spinneret) This die contains a large number of microscopic holes that help to form the molten polymer into thin strands.
As these filaments exit the spinneret, they immediately pass in front of a cold air blower, which rapidly cool and solidify the strands. From here they travel down to a series of rollers, which wind or spins the strands into rolls of fiber. Depending on the application, some of these machines may twist multiple strands together to create a thicker fiber.
Manufacturing process of polyester filament:
Polyester is a class of polymers that chiefly contains Polyethylene Terephthalate (PET). Polyester is a synthetic polymer produced using PTA and MEG.
PET is made by
- Esterification reaction between terephthalic acid and ethylene glycol, OR.
- Trans-esterification reaction between ethylene glycol and dimethyl terephthalate.
Polyethylene Terephthalate (PET) is basically produced by polymerization of ethylene glycol and terephthalic acid. To be more specific, when the two raw materials of PET- ethylene glycol and terephthalic acid are combined with low vacuum pressure and high temperatures long chains of the polymer are formed.
PTA – (Pure Terephthalic Acid)
PTA is known as Pure Terephthalic Acid. PTA is used to make polyester fiber, white crystal power that is in noxious and inflammable. It burns easily when mixed with a certain amount of air.
Terephthalic acid ( PTA) is produced from p-xylene by oxidation with oxygen. The reaction is carried out in acetic acid and the catalyst used is cobalt (or manganese) acetate and bromide. Phthalic anhydride is made from naphthalene or o-xylene by air oxidation over a heterogeneous catalyst.
PTA is an important organic raw material, widely used in the chemical fibre industry, the light industry, the electronics industry and the construction industry and some other fields. Over 90 percent of the world’s PTA is used to produce PET. Producing 1 ton of PET needs 0.85-0.86 ton of PTA and 0.33-0.34 ton of MEG. A portion of the world’s biggest PTA items supplied by British Petroleum, Reliance, Sinopec, Sk-Chemicals, Mitsui and Eastman Chemicals.
MEG – (Monoethylene Glycol)
Monoethylene Glycol (MEG) is a colorless, virtually odorless and slightly viscous liquid. It is miscible with water, alcohols, aldehydes and many organic compounds. MEG will not dissolve rubber, cellulose acetate or heavy vegetable and petroleum oils. MEG has a low volatility and it is 50% more hygroscopic than glycerol at room temperature.
MEG is not considered to be a health hazard when handled under normal industry conditions. It has a relatively low degree of acute and chronic oral toxicity .
MEG is produced by using a chemical compound ethylene. In this process ethylene oxide is produced as an intermediate and reacts with water to produce EO. Acids and Bases are used as a catalyst in this process. PEG is produced by the reaction between ethylene oxide with water and ethylene glycol or glycol oligomers.
The fully integrated plant uses Ethylene produced by Naphtha Cracker as the main feed Stock for manufacture of MEG. The MEG plant is based on the proven technology of Scientific Design Co. The nameplate capacity of the MEG plant is 303000 TPA with Di Ethylene Glycol (DEG) and Tri Ethylene Glycol (TEG) as by products.
MEG creation is in the hand of around 10 worldwide players which are going by MEGlobal a JV of DOW and PIC Kuwait took after by Sabic.
MEG transportation challenges in Bangladesh
In the MEG injection system MEG is temporarily stored in a seabed storage tank and subsequently injected into the subsea flow line. After a MEG carrier to the floater transports the regenerated MEG, the MEG is injected from the floater to the seabed storage tank. This injection system with ship-based transportation to provide an alternative to conventional MEG injection systems with pipeline-based transportation.
This system consists of a seabed storage tank, MEG carrier and a floater. A novel pressure-balancing concept is in the seabed storage tank in which seawater can both enter and exit so the internal and external link pressures are balanced. The seabed storage tank consists of a storage unit, ballast unit, and sea water cleaning unit.
In practical it is very complicated and depends on Sea port Depth, Sea carrier, Surrounding environment and a huge financial investment.
MEG manufacturing Scope in Bangladesh: In regular process MEG is manufactured form Crude oil refiner. In Bangladesh existing POY mill is manufacturing POY from virgin PET chips/Granule. This is one of the reasons the POY manufacturing cost higher then India or China. As MEG plant needs big investment and support from government to set the basic factory. So that it can support lot of mid-scale yarn manufacturing mill. Bangladesh government has one refinery project in the name of Eastern Refinery Limited which is in Chittagong. But this project can make R & D and expand to produce MEG as their refine oil by product. And this can be landmark for Bangladesh as basic Textile procuring country.
Besides this, there is another option to produce MEG from natural COAL.
The basic technology for producing ethylene glycol from coal has been around for decades. In the 1970s, Japan’s Ube Industries developed a process that harnesses synthesis gas (syngas), often made from coal, to produce ethylene glycol through a multiple-step reaction involving the consumption and regeneration of methyl nitrite. Bangladesh have own Coal mine also big import base supply chain for Coal for Power Generation and other industry.
MEG manufacturing Scope from coal
MEG and water are produced from carbon monoxide (CO), hydrogen (H 2), and oxygen (O 2) in the DMO process. The nitrite technology results in the highly selective formation of C-C bonds, enabling the production of DMO. In the MEG process, methanol is a byproduct of DMO hydrogenation, but it is recycled by the DMO process. These processes are extremely efficient and clean, and they feature an overall high level of selectivity and few byproducts.
Polyester spinning mill in Bangladesh: At present there are only 8 polyester filament spinning mill running in Bangladesh. These are:
- Modern Poly
- Kader Synthetics
- Bengal Synthetics
- Infinia Group
- Super Synthetics Ltd
- TK group
- Noman Group
This mills mainly produce DTY and FDY. The new mill can be designed from PET chips to POY and DTY also directly FDY.
Polyester spinning capitol machine manufacturer: Normally POY and FDY machine is offered by Turnkish Machine manufacturer. DTY machine is individual in the no. of spindle basis. Besides this big size, air compressor is need in the Polyester Spinning mill. Dowtherm Boiler is need, which is with the POY line and run by electricity. The main challenge is uninterrupted Electricity is need in the Production line otherwise there will be Polymer clotting and all the spinneret will be clog.
The Oerlikon Barmag one of the Old Company for filament spinning from Germany. Besides this TMT Group Japan also has long experience and TMT winder is one of the best in the market. Also, there is around 4 major manufacturers in China for POY and DTY, who have world market share more than 60%. And in India there is 2 companies who make DTY for local and international market with competitive price.
Land requirement: Normally 2 acre lands are required for ensuring 100 Crore BDT project turnover and it will increase once the capacity will be increased. The height of the POY unit is needed to be at least 20 meter with 800 Square meter per floor. The DTY has different model machine. So, depends on the machine model, floor height needs to be adjusted from 5 to 12 Meter.
Utility requirement: The gas generator is the most important part of polyester spinning. For the initial project (Turnover 100 Crore/year), it needs 1500 KW gas generator. That means around 400 M3 /Hour Gas is require to run the POY, DTY, Air Compressor and others. Very Small qty Water is required but no need the ETP. No need any Boiler. In POY unit DOWTHERM boiler is inbuilt and in DTY heater is inbuilt.
Polyester filament project investment and pay back
The Polyester filament project investment depends on production capacity, capitol machine origin, equity ratio, and cost of fund, and so on. Normally for 100 Crore BDT turnovers per year, it needs 60 Crore Taka investments by Chinese machine and 130 Crore investments by Europe origin machine. The Chinese machine in regular price payback period is 3 to 4 years and by Europe machine pay beck period is 10-12 years. But for the polyester yarn, every 2-3 years there is a scope of price hike and in that case, payback period may come down to 7 years. In the man made fiber (MMF), polyester is the most basic yarn and Chinese machine is good enough to do the new investment. The nylon and spandex can prefer Europe machine specially winder.
Raw material challenge: Bangladesh imports almost 3 billion USD worth of raw cotton fiber in every year to run the cotton spinning mill. As like cotton polyester filament spinning raw material also need to import. Still there is not any RAW material plant is set for the PET textile grade. Bottle grade plant may set within in short time in Bangladesh. In polyester spinning almost 98% Raw material is PET chips. Besides this, Spin Finish Oil, Anti-Microbial Agent, Master batch, TiO2, Paper bobbin and some small amount of raw materials are required to run the project. The beauty of polyester spinning is the process los is less than 1%.
Recycle polyester filament yarn scope in Bangladesh
The sustainable concept of the polyester spinning is to make polyester yarn from wastage PET bottle. The pet bottle collected then washed and crashed and then do the Pillarization. In the pelletizing process get PET, which is the raw material of POY plant. This project is little expensive then virgin and there is challenge of raw material crisis in the long run.
The virgin or recycle polyester filament spinning both have the demand in Bangladesh. For the Cotton made product Bangladesh garments industry has a very strong position in the world garments industry. Now it’s the time to focus on the synthetic market. Once the new investors make more polyester filament spinning plants, fabric and garments maker will be more facilitate to compete in synthetic market. The synthetic market is much bigger then cotton.