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Bonding of-nonwoven-fabric

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Bonding of nonwoven fabric

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Bonding of-nonwoven-fabric

  1. 1. Bonding of Nonwoven Fabric
  2. 2. Presented By  Kazi Habibur Rahaman 151-23-4231  Muhib Billah 151-23-4182  Md Redoy Chowdhury 153-23-4499  Farhana Zaman Shopnil 153-23-4532
  3. 3. NonWoven? Non-woven fabric is a fabric like material made from staple fibre (short) and long fibres (continuous long), bonded together by chemical, mechanical, heat or solvent treatment.
  4. 4. Why Bonding?  All fiber (Natural, Manmade) always has to achieve some specific requirements, the fiber choice with the appropriate application of bonding becomes essential  This can be achieved by comparing the requirements to be met together with their obtained results from individual fiber
  5. 5. Nonwoven fabric bonding can be defined as:  Mechanical Bonding  Chemical Bonding  Thermal Bonding  Bonding of Spun Laid Web
  6. 6. Mechanical Bonding  Mechanical bonding is when the fibers are not altered by either heat or chemicals and are instead bonded by an alternate method  Hydro-Entanglement bonding (also called spunlace), bonds the fibers by mechanically intertwining the fibers with water jets. Similar to spunlace there is also needlepunching/needlefelting which uses needles to intertwine the fibers as opposed to water jets. Also there is ultrasonic pattern bonding for use in materials that need to be a bit softer than other nonwovens.
  7. 7. Mechanical Bonding Types  Stitch Bonding  Needle Punch Technique  Hydro-Entanglement
  8. 8. Needle Punching  Needles are the heart of the needle-punching process  Needle-punching is a nonwoven process by which the fibres are mechanically entangled to produce a nonwoven fabric by repeated penetration of barbed needles through a preformed dry fibrous web.  The machine which accomplishes this process is known as needle loom.
  9. 9. Application  Geosynthetics  Filter media  Synthetic leather  Waddings and Paddings  Floor coverings  Automotive fabrics  Insulation  Blankets  Wipes  Roofing
  10. 10. Hydro Entanglement  Hydroentanglement, spunlacing, hydraulic entanglement, and water jet needling are synonymous terms describing the process of mechanically bonding the fibres in a web by means of high energy water jets.  The machine which accomplishes this is known as hydroentanglement or spunlace machine.
  11. 11. Application  Wipes  Surgical fabrics  Medical gauge  Filter cloths  Artificial leather  Automotive fabrics  Linings and clothes, etc.
  12. 12. Chemical Bonding  Chemical Bonding or sometimes referred to as adhesion bonding methods involve applying adhesive binders to webs by saturating, coating or spraying, printing (as in print bonding) or foaming technics.  Print bonding is used when specific patterns are required and where it is necessary to have the majority of fibers free of binder for functional reasons.  To Provide structural integrity and numerous other properties to achieve effective performance of nonwoven fabric
  13. 13. Chemical Bonding Types  Saturation Adhesive Bonding  Spray Adhesive Bonding  Foam Bonding  Application of powder  Print Bonding  Discontinuous Bonding
  14. 14. Foam Bonding  Air or water is used to dilute the binder and as a mean to carry the binder to the fibres.  One advantage of diluting binder with air rather than with water is that drying is faster and energy cost is reduced remarkably.  Foam is generated mechanically and can be stabilized with a stabilizing agent to prevent collapse during application.  Foam can be applied so as to remain at the surface or can be made to penetrate all the way through the fabric cross-section.
  15. 15. Spray Bonding  Typical spray bonding process.  Here the binder is sprayed onto a moving web in fine droplet form through a system of nozzles, which can be statically mounted across the machine or transverse from one side to the other side of the machine. It is used to make highly porous and bulky products.  This is possible because the substrate does not need to pass between nip rollers.
  16. 16. Spray Bonding  The main advantage of this method is that the nonwoven is not compressed and the original bulk and structure is retained.  The disadvantages include lack of control of the uniformity of spraying, poor binder penetration, high level of overspray and waste, and possible lack of shear stability of the binder.
  17. 17. Application  Wipes interlinings  Hygiene and medical products  Footwear  Automotives  Homefurnishing products.
  18. 18. Thermal Bonding  The first thermally bonded nonwovens were introduced in the 1942 by REED. The thermal bonding process also addresses the quality requirements of  new raw materials  better technologies  higher production speeds which have made thermal bonding  more economical for both durable
  19. 19. Methods  The methods for thermal bonding include the use of a heat sealer which heats the fibers until they slightly melt together and is often used in combination with a lower melting point binder fiber.  The second is using a large oven for curing which works basically the same as the heat sealer except after the fibers are heated they are then left to dry out harden  The final method is calendaring through heated rollers (called spun bond when combined with spun laid webs), calendars can be smooth faced for an overall bond or patterned for a softer, more tear resistant bond (see close-up on left).
  20. 20. Principle The formation of a bond during thermal bonding follows in sequence through three critical steps:  heating the web to partially melt the crystalline region,  repetition of the newly released chain segments across the fibre-fibre interface, and  subsequent cooling of the web to re-solidify it and to trap the chain segments that diffused across the fibre-fibre interface.
  21. 21. Thermal Bonding Types  Hot Calendaring  Belt Calendaring  Through Air Thermal Bonding  Ultrasonic Bonding  Radiant Heat Bonding