Types of Spinning (Man-Made Fibers)

The polymer being spun must be converted into a fluid state. If the polymer is a thermoplastic then it is just melted, if not then it may be dissolved in a solvent or chemically treated to form soluble or thermoplastic derivatives. The fluid polymer is then forced through the spinneret, where the polymer cools to a rubbery state, and then a solidified state.
There are four types of spinning: wet, dry, melt, and gel spinning.

Wet Spinning


Wet Spinning (Rayon)
In this method the common man made fibres spun are viscose rayon, alginate, acrylic fibres etc. the fibre forming polymer solution first de aerated and then pumped under pressure through metering pump unit, them through the filter and finally through the spinneret. The spinnerets are immersed in a spin bath containing coagulating fluid at a reasonable temperature, as the polymer solution emerges from the spinneret and travel through the bath it becomes coagulated by the chemicals of the spin bath.
Dia of holes, rate of solution feeding and rate of holes per spinneret may be 100000 numbers per squa4e inch diameter and space of holes in the spinneret could be varied.

Typical Wet Spun Fibers:
  • Viscose
  • Acrilan
  • Creslan

Disadvantages:
  • Slow(70-150 yds/min)
  • Washing to remove impurities
  • Solvent and chemical recovery

Advantages:
  • Large tows can be handled

Dry Spinning:


One of the three spinning methods for spinning man made fibre is dry spinning method. Fibres produced by this techniques are acetate rayon, acrylic fibres etc. In this technique fibre forming materials are dissolved in volatile solvent. Each spinning unit consists of a pump and spinneret at the top pf a tall shaft about 9 to 15 feet high. There is an air outlet at the top of the tall shift and air in let at the bottom. The fibre spinning solution is forced under pressure from the storage tank to the spinning pump and then through the spinneret.
The number of holes, dia of holes and shape of holes varies according to requirements of a spinneret. The fineness of the filament is determined partly by the diameter of the holes but primarily by the relation between the rate at which solution is forced through the spinneret and rate at which the yarn is wind up. When the fibre spinning solution emerging from spinneret meet the worm air, volatile solvent evaporates leaving the filaments, hence coagulation takes place and becomes dried before leaving the chamber.

Typical Dry Spun Fibers:
  • Acetate (acetone solvent)
  • Triacetate (methylene chloride)
  • Spandex(some) (dimethyl formamide)

Disadvantages:
  • Flammable solvent hazards
  • Solvent recovery
  • Slow(?) (200-400 yds/min)

Advantages:
  • Yarn does not require purification

Melt Spinning:


In this technique, the common man made fibres spun are Nylon, polypropylene etc. the fibre forming polymer chips are fed through a hopper into a spinning vessel. In spinning vessel, melts by the heated grid and passes through the grid mesh and collected on the pool. The n the melt is metered by a pump through a filter and finallyu through the spinneret.
The melt solidifies immediately it issues from the jets and so form filaments passes through a cooling chamber in which cold air current swept across the filaments. The spinning speed is approximately 1200 meters per minute.
Melt spinning has two big advantages over dry spinning. It avoids the need for a solvent recovery plant and loss of solvent during recover. The high fibre spinning speeds that are possible here.

Typical Melt Spun Fibers:
  • Nylons
  • Polyester
  • Polypropylene

Disadvantages:
  • Seperate drawing step (unless spin draw)

Advantages:
  • High speed (275 to 1500 yds/min)(4000 yds/min spin draw)
  • No solvents
  • No purification problems

25 comments:

la com├ędie said...

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bingbloggt.de said...

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Even said...

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amidoinitrite? said...

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Tchez said...

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MusicGooze said...

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textileengineer said...

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MusicGooze said...

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Kartoffeln said...

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NJS DailyBlog said...

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Cacti said...

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Jakeman-Jensen said...

This was an amazing read - I actually feel smart now xD Thanks =D

ramesh chauhan said...

THANKS FOR THE LOVELY COMMENTS! I AM GLAD YOU LIKE THE POST ASWELL! MORE TO COME!

Wet and gel spinning - FET designs and manufactures Laboratory and Pilot Wet and Gel Spinning Systems. This process is used for polymers that need to be dissolved in a solvent to be spun.

ramesh chauhan said...

Great post . It takes me almost half an hour to read the whole post. Definitely this one of the informative and useful post to me. Thanks for the share.

Melt spun fibres and yarns - FET supplies bespoke extrusion equipment for the manufacture of absorbable and resorbable yarns, fibres and polymers.

jyoti kumari said...

Thank you for sharing valuable information. Nice post. I enjoyed reading this post. The whole blog is very nice found some good stuff and good information here Thanks..Also visit my page Melt spun fibres and yarns FET has such a track record. As an established reputable provider, FET designs, develops and manufactures extrusion equipment for a wide range of high value textile material applications worldwide.





Kiron said...

Nice article.

Sadia said...

Great post on spinning.

Rihan said...

nice written.

Sunni Speaker said...

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Jou said...

This is Prof. J. Jou. Saying hello form National Tsing Hua University, Taiwan, thank you for providing these remarkable figures!
I am writing to inquire if I could have your permission to quote your dry spinning figure in my new book, entitled “Introduction of Material Science and Engineering.” This figure is the best one among all I can found. Sincerely hope I can use this great work in the textbook; it would be grateful if you could kindly grant me the permission.
Please contact me by jjou@mx.nthu.edu.tw for further discussion. Thank you very much for your time. I look forward to hearing from you soon.

Sincerely yours
Jou, Jwo-Huei

Professor, Department of Materials Science and Engineering, National Tsing-Hua Univ., Hsin-Chu, Taiwan.
President, Chinese Organic Electronics Association, Taiwan.
Ph. D, University of Michigan, Ann Arbor, Michigan, USA, 1986.
Visiting Scientist, IBM-Almaden Research Center, San Jose, CA, USA, 1986-8

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