March 02, 2009

Lycra Yarn – Pretreatment in Package dyeing machine:

Machine Circulation Cycle Settings:

Cheese winding: on plastic cones or cheeses.

Cheese Weight : Not more than 500 grams/cheese


    • Recipe:

      • Kierlon Jet B Conc = 0.05%

      • Lufibrol MFD = 0.05%

        • @ 50°C for 2 cycles

        • This is done to remove the unwanted mineral contents from the fiber.

  • Hot Wash = 1 cycle @ 50°C

  • Cold Wash = 1 cycle


    • Recipe:

      • Soda Ash = 2.0%

      • Stabilizer = 0.5%

      • Lissopol D paste = 0.5%

      • Hydrogen Peroxide(50%) = 2.0%

        • @ 65° to 70°C for 45 to 60 minutes.

        • Set the bath with chemicals other than H2O2.

        • Raise temperature @ 1.5°C/minute

        • Hot Wash = 1 cycle @ 50°C

  • Peroxide Killer Treatment:

    • Recipe:

      • Organic Peroxide killer = 0.25%

      • Acetic acid = 1.5 g/l

        • @ 50°C for 1 cycle

  • Drain, Cold wash

  • Start Dyeing.


1. Bleaching temperature should not go beyond 65 to 70°C

2. Cheese weight = 500 grams and less is safer.

3. If you want to use regular cheese weights of 800 to 1000 grams, then the cheeses have to be conditioned in the autoclave with moist steam at 100°C for 30 minutes, repeatedly, so that a stable shrinkage percentage of yarn is reached. The linear shrinkage % should be 20 to 25%.

What is Lycra? Lycra yarn and its properties.

LYCRA® is a man-made elastic fibre invented and produced only by DuPont®.It’s remarkable properties of stretch and recovery enhance all fabrics and garments in which it is used, adding easy comfort and freedom of movement and improving fit and shape retention. Swimwear and lingerie owe their figure-flattering fit to LYCRA®. All types of hosiery are softer, smoother-fitting and more durable thanks to LYCRA®. In short, a little bit of LYCRA® makes all types of apparel fit better, feel better and look better. Tech-Talk

LYCRA® belongs to the generic elastane classification of man-made fibres(known as spandex in the US and Canada) and is described in technical terms as a segmented polyurethane it is composed of “soft”, or flexible, segments bonded together with “hard”, or rigid, segments. This gives the fibre it’s built-in, lasting elasticity.

LYCRA can be stretched four to seven times its initial length, yet springs back to it’s original length once tension is released.

While LYCRA® appears to be a single continuous thread, it is in reality a bundle of tiny filaments.

How LYCRA® is used

LYCRA® is never used alone; it is always combined with another fiber (or fibers), natural or man-made. Fabrics enhanced with LYCRA® retain the appearance of the majority fibre.

The type of fabric and it’s end use determine the amount and type of LYCRA® required to ensure optimum performance and aesthetics. As little as 2 percent LYCRA® is enough to improve a fabric’s movement, drape and shape retention, while fabrics for high-performance garments such as swimwear and active sportwear may contain as much as 20-30 percent LYCRA®. Weaving or knitting techniques, togheter with fabric type and end use, determine whether LYCRA® is used in a bare or covered yarn form.

Single and double covered LYCRA®

Core-twisted LYCRA®

The material used in the making of the Cotton-Lycra line of Snob underwear consist of:

-90% Cotton
-10% Spandex(Lycra®)

Cotton-Lycra Care
-Machine wash in warm water.
-Do NOT use Chlorine bleach.
-Tumble dry at low temperature.

Courtesy: Dupont Lycra®