Yarn conditioning is a process in which yarn is conditioned for better performance (such as strength, serviceability, luster, handle, etc.)
Textile fibers are subjected to varied physical operations to form into a yarn. For example, cotton fiber passes through opening, carding, drawing, and spinning; after all this process it becomes a yarn. During these phases, the first moisture content on the fiber would are lost and a few electricity would be carried by the fiber. The amount of static current that is carried by yarn changes from fiber to fiber. Similarly, the strength of any fiber depends abreast on how close this moisture content is to the first natural value.
Similarly, some high twist yarn would tend to lose its twist as and when it’s allowed freely, making a lengthwise elongation. Some fibers will have the nature of shrinking when exposed to the hot atmosphere or any treatment that involves heat and hence higher temperatures. For example polyamide, polyester, etc. Some blends like Cotton/Lycra, Viscose/Lycra require conditioning to form the width of the material stable.
So all the above said factors, if not addressed properly would reflect badly on the ultimate quality of yarn or fabric.
Moisture in the atmosphere features a great impact on the physical properties of textile fibers and yarns. Relative humidity and temperature will decide the quantity of moisture within the atmosphere. The high ratio in several departments of spinning isn’t desirable. It will result in major problems. But on the other hand, a high degree of moisture improves the physical properties of the yarn. Moreover, it helps the yarn to achieve the quality moisture regain the value of the fiber. Yarns sold with lower moisture content than the quality value will end in monetary loss. Therefore the aim of CONDITIONING is to supply a cheap device for supplying the required moisture for a short time, so as to realize an enduring improvement in quality.
The ratio, in turn, affects the properties of the fiber via the moisture content of the cotton fiber. The fiber strength and elasticity increase proportionately with the rise in humidity. If the water content of the cotton fiber is increased the fiber is in a position to swell, leading to increased fiber to fiber friction within the twisted yarn structure. This positive alteration within the properties of the fiber will again have a positive effect on the strength and elasticity of the yarn. A process that addresses all the above parameters is named CONDITIONING. The conditioning process differs from fiber to fiber.
So conditioning may be a preliminary process in any processing that improves and maintains the standard of yarn. Conditioning Process for various yarns:
1) 100% Polyester yarn: Load the yarn in the form of cones wound on plastic cones, into a beam dyeing machine. Introduce steam and lift the temperature to 100°C at 3°C per minute. Steam for quarter-hour at 100°C followed by quarter-hour cooling = 1 cycle. Repeat the cycle for 4 times.
2) 100% Nylon: Load the yarn in the form of cones wound on plastic cones, into a beam dyeing machine. Introduce steam and raise the temperature to 100°C at 3°C per minute. Steam for quarter-hour at 100°C followed by quarter-hour cooling to a temperature of 50°C = 1 cycle. Repeat the cycle for 4 times.
3) Silk yarn: Load the yarn in the form of cones wound on plastic cones, into a beam dyeing machine. Introduce steam and raise the temperature to 70°C at 3°C per minute. Steam for quarter-hour at 70°C followed by quarter-hour cooling to a temperature of 30°C = 1 cycle. Repeat the cycle for 4 times.
4) Cotton/Lycra (40’s Lycra) or Viscose/Lycra (60’s): Conditioning the yarn as mentioned for silk.
There are different types of yarn conditioning plants. The following effects would be envisaged by steam-conditioning of yarn:
- Twist Setting – Preventing Snarling (yarn loops)
- Better Dye affinity – Eliminating static electricity
- Influencing the Cloth handle – Preventing crease-proneness
- High bulking – Humidifying
- Dye – fixing – De-crinkling.