Man made fiber spinning


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Man made fiber spinning

  1. 1. Man Made Fiber Spinning
  2. 2. Prepared By : Mazadul Hasan sheshir ID: 2010000400008 13th Batch (session 2009-2013) Department : Wet Processing Technology Email: Blog : www. (visit) Southeast University Department Of Textile Engineering I/A 251,252 Tejgaon Dhaka Bangladesh Prepared By : ©right
  3. 3. Calssificatoin of fibres
  4. 4. Forms of Man Made fibre: MMF are produced in three types – 1. Filament:Filament fibres are spun from spinnerets with 350 holes or less is determined by the size of the yarn to be made Monofilament: This filament is made only of a single filament. Multifilament: These filaments are made of more than one filament. 2. Staple:Staple fibre is of limited and relatively short length 3. Filament tow. An assemble of twist free fibre.
  5. 5. Properties required for Fibre forming polymer: •Molecular weight should be high. •Crystallinity – high not suitable. •Resistance to different chemical. •Orientation – Physical and chemical symmetry. •Straight chain structure. •Glass Transition Temperature (Tg) – Should be near to Room Temp. •Crystalline Melting Point (Tm) - 200o – 300o c is suitable. •Polymer should be soluble in some solvent from which it can be spun. •Hygroscopic nature – Should be hydrophobic
  6. 6. Synthetic Spinning System
  7. 7. • Spinneret: A nozzle or plate provided with fire holes or slits through a fibre forming solution or melt is extruded in fibre manufacturing is called spinneret. This is the most important part of a MMF producing m/c. The number of holes, sizes and shapes vary with the filament desired. • Shape of holes: Spinneret
  8. 8. Features of Spinneret: Spinneret length: 10-25 mm Spinneret diameter: 30-200 mm Spinneret thickness: 3.0 mm Hole dia: 0.1.-0.8 mm Problems: -Breaking (On account of high pressure and temp) Clogging (The holes can be blocked for solid particles mix with polymer solution). Remedies: -For breaking problem: the spinneret is to be changed. -For clogging: the spinneret should be cleaned after some days.
  9. 9. Number of holes in spinneret: 1. For monofilament:1-3 2. For multifilament: 100-1000 3. Filament tow: up to 50,000
  10. 10. Flow chart of MMF production: 1. Manufacture of the fibre forming polymer. 2. Spinning ( extrusion through spinneret) 3. Stretching/Drawing ( improving strength and crystallinity) 4. Texturing/Crimping ( developing natural fibre properties) 5. Intermingling/Interlacing( applied instead of twisting) 6. Heat setting( made dimensionally stable) 7. Cutting: According to requirements.
  11. 11. 1. Manufacturing of the fibre forming polymer: • All man made fibres are composed of long chain molecules known as polymer which are formed by chemical processing. • Common groups in polymers – – Amide or Peptide groups ( -CO-NH-) – Benzene ring – Ether linkage( -C-O-C-) – Ester linkage(-C-O-O-) – Hydroxyl group (-OH) – Nitrile group (-C-N-)
  12. 12. Spinning: • The conversion of polymer into fibre is called spinning. The fibre forming substance is made temporarily fluid, extruded through spinneret and then returned to solid state (by solidification) in fibre form. • Three types of spinning process: – Melt spinning (Synthetic). – Wet spinning. – Dry spinning.
  13. 13. SPINNING of polymers There are typically three types of spinning for polymers: Melt, Dry and Wet. ▪ Melt spinning (Fig. 1) is used for polymers that can be melted easily. ▪ Dry spinning (Fig. 2) involves dissolving the polymer into a solution that can be evaporated. ▪ Wet spinning (Fig. 3) is used when the solvent cannot be evaporated and must be removed by chemical means. Melt spinning In melt spinning the fibre-forming material is melted and extruded through spinnerets, and the jets harden into solid filaments as they cool on emerging from the spinneret. Nylon is a melt-spun fibre. Dry spinning In dry spinning the fibre-forming substance is dissolved in a solvent before the solution is extruded. As the jets of solution emerge from the spinneret, a stream of hot air causes the solvent to evaporate from the spinning solution, leaving solid filaments. Acetate is dry spun by extruding acetone solutions of cellulose acetate into hot air. Wet spinning In wet spinning the solution of fibre-forming material is extruded into a coagulating bath that causes the jets to harden as a result of chemical or physical change. Viscose, for example, is wet spun. The solution of cellulose xanthate is extruded into an aqueous solution of acids and salts, in which the cellulose is regenerated to form solid filaments. Man Made Fiber Spinning Technology
  14. 14. Man Made Fiber Spinning Technology
  15. 15. 02. Spinning: Melt spinning: • The process of spinning by which fibre or filament is produced from melted polymer chips by extruding through spinneret continuous filament produced here. • Number of filament depends on number of holes in spinneret. • It is the most critical operation in the production of nylon polyester, and polyolefin, poly propylene fibres as number of fibre properties such as uniformity, crystallinity, and orientation are imparted to the yarn during processing.
  16. 16. 02. Spinning: Melt spinning: • .Feed Melting Cooling & solidification by cold air. Moisture conditioning Lubrication Yarn driving Packaging Flow Chart Metered extrusion
  17. 17. 02. Spinning: Melt spinning: Advantage: – Can be used for both staple and continuous filament. – Direct and simple process. – No environment pollution. – No solvent required. – Non toxicity and no risk of explosion. – High production speed (2500 – 3000 ft/min) – Low investment cost. • Disadvantage: – Required more proper maintenance of the m/c. – Heat of input is high.
  18. 18. 02. Spinning: Melt spinning: Typical melt spinning: Polymer Melting point Nylon – 6, 6 264oC Nylon – 6 220oC PET 264oC Polypropylene 167oC Poly ethylene 125oC
  19. 19. 02. Spinning: Dry spinning: • In dry spgn, the fibre forming polymer dissolved in a volatile solvent is introduced into a heated drying chamber where the solvent is evaporated and solid fibre is obtained through spinneret. • This process is used for Acetate and some polyacrylonitrile fibre.
  20. 20. 02. Spinning: Dry spinning: • Dry spinning solvent: Fibre Solvent I) Cellulose -Acetone + (2-6) % water II) II) Triacetate -Methylene chloride (40%) + Methanol (10%) III) Poly acrylonitrile -Di-methyl formamide or Dimethyl acetamide. IV) Spandex - DMF, DMAC. V) Modacrylic - Acetone.
  21. 21. 02. Spinning: Dry spinning: • . Feed Metered extrusion Solidification by solvent Evaporation Lubrication Yarn driving Packaging
  22. 22. Dry spinning Process
  23. 23. Dry spinning Process
  24. 24. 02. Spinning: Dry spinning: • Advantage: – Suitable for producing fine denier fibres. – No need of wash of fibre. • Disadvantage: – Investment cost is high. – Toxic and risk of explosion. – Heat input is very high. – Can not be used for staple fibre production. • Properties of solvent: – Solvent should not be volatile. – It should be organic. – It should have low boiling point. – It should be comparatively cheap. – It should be thermally stabilized. – It should be non toxic.
  25. 25. 02. Spinning: Wet spinning: • In wet spinning a suitable solvent is used to prepare fibre forming solution and another coagulant is used in coagulating bath. • Solution is extruded through spinneret and in contact of coagulant cellulose is regenerated. • Wet spgn solvent & coagulant: Fibre Solvent Coagulant Viscose Alkaline water Dill H2SO4 + Na2SO4 +ZnSO4 PVA Water Aqueous NaOH PAN DMF/DMC + Aq DMF/DMC + 40% ZnCl2 • 60% ZnCl2
  26. 26. 02. Spinning: Wet spinning: Coagulation bath Washing Bath
  27. 27. 02. Spinning: Wet spinning:
  28. 28. 02. Spinning: Wet spinning: • Advantage: – Suitable for staple fibre. – Both organic and inorganic solvent can be used. – Low temp reqd. – Higher production due to continue spgn. – Softener process. – Investment cost is low. • Disadvantage: – Slow spgn speed. – Washing and bleaching of fibres are needed. – Toxic.
  29. 29. 02. Spinning: Difference Parameter Melt spgn Dry spgn Wet spgn 1. Investment cost Low High Low 2. Hazard Non toxic Toxic Toxic 3. Heat of spgn High Very high Low 4. Spinneret hole 2 – many thousands 300 – 900 20000 – 75000 5. Spgn speed 2500 – 3000 ft/min 2500 – 3000 ft/min 150 – 300 ft/min 6. Productivity High Low High 7. Application Filament or staple Filament Filament or staple 8. Solvent Not required Only volatile organic solvent Both organic and inorganic solvent can be use.
  30. 30. Features Melt Dry Wet Investment Cost Low High Low Hazard Non-toxic Toxic (Risk of explosion) Toxic Heat of Spinning High High Low Spinneret Hole 2 to many thousand 300-900 20,000-75,000 Spinning Speed 2500-3000 ft/min 2500-3000 ft/min 150-300 ft/min Comparative features of melt, dry and wet spinning
  31. 31. •Production does not depend on climate & location. •Quality & quantity can be controlled during production. •Length & thickness can be controlled as per requirement. •Staple length can be controlled as per requirement. •Smoothness and high luster. •Fiber processing is easier. •High productivity and low cost. Advantage of man-made fiber technology:
  32. 32. 1. Fabrics made of MMF are difficult to stitch. 2. Low air permeability. 3. Uncomfortable. 4. Unhygienic. 5. Hydrophobic. Disadvantage of man-made fiber technology:
  33. 33. 1. Yarn Manufacturing Technology Link : 2. Fabric Manufacturing Technology Link : 3. Garments Manufacturing Technology Link : Technology/472364799463126 3. Wet processing Technology Link : 4. Fashion-Design-and-Technology Link : Technology/587655294583875?ref=ts&fref=ts My Facebook Textile related Pages (Visit My Blog for more Info )
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