The document discusses heat setting of synthetic fibers. Heat setting involves applying heat to fibers to impart shape retention, crease resistance and elasticity. It causes structural and chemical changes in the fibers as the polymer chains come closer together through increased hydrogen bonding and Van der Waals forces, making the fiber structure more stable. There are different stages and methods of heat setting, including contact, steam, hydro and tenter frame methods. Heat setting affects various fiber properties such as structure, dimensions, stiffness, crease recovery and dyeability.

1. Welcome
Topic: Heat Setting

2. Submitted by:
Submitted to:
Md. Aminul Islam Mishuk
Assistant Professor, Department of Textile Engineering (BUBT)
Md.Ibrahim Khalil
Intake:19
Department Of Textile Engineering
Bangladesh University Of Business & Technology

3. Introduction
 Heat setting is a heat treatment by which shape
retention, crease resistance, resilience and elasticity
are imparted to the fibers.
 Change in strength, stretch ability, softness , dye
ability and sometimes in color.
 Changes occur due to structural and chemical
modification of fibers.

4. Thermal Behavior of Synthetic Fibers
 They consist of long chain molecules randomly
held immediately after spinning.
 Fibers are stretched several times their length to
impart desirable properties.
 As chains come more closer, there is increased H-
bonding and van der wall forces.
 This makes the structure more stable.

6. Process of Thermosetting
1. Heating phrase
2. Penetration phrase
3. Transition and stretch phrase
4. Cooling phase

7. Stags of Heat Setting
Heat setting can be carried out at three
different stages:
 In grey condition
 After scouring
 After dyeing

8. Heat Setting at Grey Stage
 If heat setting is carried out in loom state, mineral oils and
non-ionic emulsifiers can modify the fiber.
 Structure and rubbing and perspiration fastness may be reduced
due to the solubility of disperse dye in the coning oil.
 However, grey heat setting is useful in warp knitting industry as
in that material carry less amount of lubricants.
 Yellow color due to heat setting can be removed by bleaching.
 Fabric is less sensitive to crease formation in next processes.

9. Heat Setting After Scouring
Heat setting is done after scouring if it is
suspected that:
 goods will shrink .
 Cloth has developed stretch or other
properties after scouring.

10. Heat Setting After Dyeing
These fabric shows considerable resistance to
stripping compared with dyeing on unset fabric.
Disadvantage of this are:
 Yellow color developed can not be removed.
 Handle of cloth may get altered
 Risk of color to get fade

11. Method of Heat Setting
 Contact method
 Steam setting method
 Hydro setting method
 Heat setting using tenter frame
 Selective infra red emitter method

12. Contact Method
 Fabric is run in contact with heated metal surface.
 Mainly used for polyester/cotton blended fabrics.
 Width of the fabrics can not be controlled
while fabrics run flat against the roller surface.
 Variation on degree of setting can be caused due
to variation in tension.

13. Steam Setting Method
 Short staple polyester yarn including polyester/cotton
blends are normally set by relaxation in saturated steam.
 Steaming is carried out in an autoclave fitted with vacuum
pump.
 Woven or knitted fabrics are batched in open width on to a
perforated roller and saturated steam is then injected.

14. Hydro Setting Method
 Hydro Heat setting is done with hot water in a high temperature
liquid circulating machine.
 Fabric in flat form is batched onto a perforated metal cylinder
and immersed in hot or boiling water for a shorter period of time.
 Water promotes swelling and may cause hydrolysis leading
to depolymerization.
 Hydro setting at boil is equivalent to dry setting at 185.

15. Heat Setting Under Tenter Frame
 Stenters are widely used for stretching, drying, heat setting and finishing of
fabrics.
 Fabric is held by pins mounted on base plate or by chips in which fiber edge
is clamped
 Sections of stenter rails:
1. Feeding in, with padding mangle.
2. Shrinkage apparatus.
 The choice of heating system used can be direct gas, indirect steam or
oil heating or electrical heating.

16. Fig: Tenter Frame Machine

17. Selective Infra Red Emitter Method
 Textiles are exposed under selected areas of magnetic spectrum
of infra red rays.
 Wavelength of radiation source must be chosen the absorption
band of fiber.
 Energy is given to the internal fiber structure.
 Absorbed energy is redistributed within the structure of fiber, H-
bonds and van der wall forces binding the molecules together.
 They arrange themselves into position of lowest energy.(least
stress).

18. Effect of Heat Setting on Various Properties
of Synthetic Fibers
 Structural changes
 Dimensional stability
 Stiffness
 Crease recovery
 Dyeability