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Recycle Polyester: Way to Safe Environment and Energy

Over the last few years, the demand of synthetic fibre is growing up and the manufacturing ratio of natural to synthetic fibers has come to 35% to 65%. Among them polyester is the most useful and demanding synthetic fibre. This growth can be attributed to a number of causes- relatively low prices, easy manageability, technologically competent products and processes, rising demand of technical textiles. This advantage is valid no more due to the increasing costs of energy, transportation and raw materials which are used in the production process of polyester. Moreover manufacturing process of polyester causes serious environment related problem. Another important challenge before the polyester sector is that of awareness about the environmental degradation and growing demand for eco friendly products. Already there is a demand from consumers for eco-labels that provide information on how many grams of carbon dioxide or equivalent greenhouse gas emissions arose in production, transport and storage of a given product. And at this kind of situation Recycle Polyester has come in the scene to minimize these problems and full fill the customer demands.

What is Recycle Polyester?

Recycled Polyester is manufactured by using previously used polyester items like PET bottles, polyester cloths etc. In the clothing world, recycled polyester clothes can be created from used clothes. Polyester is a plastic, invented in Britain in the early 1940s by two gentlemen working with synthetic polymers. Polyester is made from Polyethylene Terepthalate (PET). This material is also use for making many plastic drink bottle. Many drink bottles are recycled by being reheated and turned into polyester fibers.

Reasons to Find a Replacement for Polyester :

technical_note_clip_image002Floating plastic mass somewhere in pacific ocean

The mass of debris in the photo is, apparently, a tiny part of what the Wall Street Journal reported as afloated in the Pacific. Nobody really knows how big it is: “Some say it is about the size of Quebec, or 600,000 square miles — also described as twice the size of Texas. Others say this expanse of junk swept together by currents is the size of the U.S. — 3.8 million square miles. Or, it could be twice of that size.”

In the above picture it’s a mass of floating plastic. Nobody seems to be able to agree on the size, or even whether the plastic is dangerous or serving a function. Plastics can harm ocean birds and mammals who eat it, because they carry toxic substances, can pierce internal organs and can trick animals into thinking they are full. “It’s so hard to say a bird died due to plastic in its stomach,” says Holly Bamford, director of the National Oceanic and Atmospheric Administration’s marine-debris program. “We have seen birds mature and live out their whole life, and necropsies show plastic in their stomach.” On the other hand, David Karl, an oceanographer at the University of Hawaii, says that the plastics have a high concentration of microorganisims clinging to them which are producing oxygen.

Polyester, or PET, is a major component of this trash because PET is the major component of beverage containers (like bottled water). But most PET (60% of global production) is used to make fibers and about 30% is used to make bottles. In addition to the fact that this polyester remains in our oceans and landfills for around 1,000 years, it’s a very expensive way to spend our energy resources.

Secondly, polyester production, running at around 50 million tons per year, consumes about 104 million barrels of oil for production (and that doesn’t include the energy needed for transportation).It also create lots of environmental problem that’s why polyester consider as non ecofriendly textile .

technical_note_clip_image004

 

The principle ingredient used in the manufacture of polyester is ethylene, which is derived from petroleum. In this process, ethylene is the polymer, the chemical building block of polyester, and the chemical process that produces the finished polyester is called polymerization.

Two gases are made from Petrochemistry industry

  1. CO2 Burning of Carbon Based Fuels
  2. N2O Fossil Fuels and Fertilizer.

The production process of the main ingradient of polyester creates lots of CO2. So the production process of polyester helps to create green house effect. With increasing carbon dioxide emissions from human, the green house effect has become drastically exaggerated .This has caused a dangerous global warming process that is threatening for our environment by melting polar ice caps and raising sea levels around the globe. It is predicted that the Earth’s average sea level will rise by 0.09 to 0.88 m between 1990 and 2100.

technical_note_clip_image006 Fig: Smoke produced in petrochemical Industry

Thirdly, polyester production process requires a lot of petroleum based product and also lot of oil consuming process. Its effect are shown by the following figure ;
technical_note_clip_image008Fourthly, traditional synthetic polyester has potential health hazards also. During the manufacturing stage antimony is used which create harmful effect on health. Antimony is toxic to the heart, lungs, liver and skin. Manufacture of polyester produces a by-product called antimony trioxide. Long term, inhalation of antimony trioxide can cause chronic bronchitis and even emphysema. the antimony trioxide mixes with the wastewater and that end up with toxic wastewater.

Scope of Recycle Polyester :

Energy needed to make the recycling polyester is less than what was needed to make the virgin polyester in the first place, so we can save energy.

Recycling polyester uses less energy that what’s needed to produce virgin polyester. Various studies from which all agree that it takes from 33% to 53% less energy. The amount of energy needed to produce recycled polyester in relation to other fibers is:

Embodied Energy used in production of various fibers:

energy use in MJ per KG of fiber:

hemp, organic

2

Flax

10

hemp, conventional

12

cotton, organic, India

12

cotton, organic, USA

14

cotton,conventional

55

Wool

63

Recycle polyester

66

Viscose

100

Polypropylene

115

Polyester

125

Acrylic

175

Nylon

250

Plastic bottle and other plastic which do not mix with environment can also keep out from landfills by using them into recycling process.

Recycle polyester is also producing far fewer emissions to the air than does the production of virgin polyester. Following Data from the Stockholm environment institute shows the emissions to the air from different fibre.

KG of CO2 emissions per ton of spun fiber:

crop cultivation

fiber production

TOTAL

polyester USA

0

9.52

9.52

cotton, conventional, USA

4.2

1.7

5.89

rPET

5.19

hemp, conventional

1.9

2.15

4.1

cotton, organic, India

2

1.8

3.75

cotton, organic, USA

0.9

1.45

2.35

From this presentation it is found that recycle polyester require less energy for production and also emit less CO2 to the earth than virgin polyester.

USA recycle only about 20% of their plastic bottles for making polyester fibre. If consumer have easy way to throw bottle into recycle process and if they become aware about recylcling process then it will helps us to reduce pressure on environment .

There are two types of recycling process: mechanical and chemical:

•Mechanical recycling is accomplished by melting the plastic and re-extruding it to make yarns. However, this can only be done few times before the molecular structure breaks down and makes the yarn suitable only for the landfill where it may never degrade, may biodegrade very slowly, or may add harmful materials to the environment as it breaks down (such as antimony).

•Chemical recycling means breaking the polymer into its molecular parts and reforming the molecule into a yarn of equal strength and beauty as the original. The technology to separate out the different chemical building blocks (called de polymerization) so they can be reassembled (re polymerization) is very costly.

Most recycling is done mechanically. Chemical recycling does create a new plastic which is of the same quality as the original, but the process is very expensive.

technical_note_clip_image010technical_note_clip_image012

Patagonia a successful Name:

Patagonia has become quite famous for its recycled polyester clothes. They are successful to produce polyester garments using previously worn garments. They are renowned for world’s first garment recycling program –this encourages customers to bring their used clothing back for recycling. Patagonia encourages customers to bring in their used Capilene baselayer, Patagonia fleece or Polartec® fleece. The fabric of these items makes them suitable for recycling. Patagonia can create a new garment made from the recycled polyester.

How does the fabric recycling process work (process used in Patagonia):

  1. The garments are cut into small pieces. Zippers and buttons are separated from the fabric.
  2. The fabric is granulated and formed into small pellets.
  3. The pellets are broken down to the molecular level and purified to produce raw material for polyester.
  4. The raw material is polymerized and turned into polyester chips.
  5. The chips are melted and spun into new filament fiber.
  6. The fiber is used to make new polyester fabrics.

Since 1993 Patagonia has been making fleece from recycled plastics, such as soda bottles and plastic shower curtains. Over the years, they have expanded their “recycled” offering to include polyester shells, running shorts and even jeans made with hemp-poly blends.

Recycled Polyester Garments:

technical_note_clip_image013technical_note_clip_image014Conclusion

The Dyer faces some problem during processing recycle polyester yarn such as color inconsistency between batch to batch, more dye consumption and deviation of base color recycle polyester from original polyester yarn. But comparing the advantages to the environment, energy saving etc. these problems are nothing. As polyester produce in large quantity and do not mix with soil, sometimes also found in some animal’s stomach. So it is every one’s duty not to through them on earth. They should put this on recycling process. Entrepreneurs should come forward to establish this kind of project to save the environment and world resource and their own benefit as well.

Reference:

1. //www.natural-environment .com/
2. //www.patagonia.com/
3.//www.oecotextiles.wordpress.com/
4.//www.testex.com/Appearal_Production_Using _Eco_Friendly _Textile .pdf

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