ELASTANE OR SPANDEX OR LYCRA SINGLE JERSEY FABRIC HEAT SETTING

  ELASTANE OR SPANDEX OR LYCRA SINGLE JERSEY FABRIC HEAT SETTING : 

Why Heat Set is important

 Lycra  is always feed in to the fabric at draft ratio .  Because of the high draft of elastane  or spandex whatever we say , the fabric always tries to relax to its original length. Due to different wet processing stages, it becomes very bulky by relaxation and causes various processing defects. As a precaution for such defects, it is necessary to heat set the fabric prior to Wet Processing.

 Heat Set process sets the fabric to a new width where it become stable and would not be able to relax further below the heat set width (within a definite tolerance)

 The new width is set by raising the temperature of heat set media to the glass optimum temperature of the spandex by passing the fabric at the desired width through the heat set chamber then this process is called heat setting process .

 For Knife open width fabrics, heat setting is done through Stenter .There are available machines are available in the market for tube fabrics heat setting. Heat Set of CK fabric can be done in 2 ways: 1. Circular frame tubular Heat Set
 Stenter heat set in open width form always .

Now a days Knitting tube  fabric with spandex is done in open width form & some for tube forms due to use of neck binding of garments item .

Hence Stenter heat set is most common type of Heat Set.

Causes of relaxation of knit  fabric before Heat Set

a) Knitted fabrics because of its intermesh of loops already have stretchability & it tends to relax even further the moment it is allowed, thus having better recovery.

b) As the degree of relaxation of a fabric varies due to different conditions of handling of fabric, there is always a possibility of uneven distribution of mass on a knitted fabric prior to heat setting.

c) As the fabric enters the heat setting chamber with the varial mass distribution, it also comes out after heat set with the same level of unevenness. This causes the gsm variation in a knitted fabric even after finishing. For that reason we need to relax fabric before heat set .

d) We also can do that before heat set if we roll the fabric roll into a plastic pipe roll then it will have same gsm everywhere , In this process we can keep it like 24 hours & then we can unroll the fabric from the plastic roll & again relax for 24 hours & need to check gsm . I have done this & got good result . So you can try for this step .