What is Blending?
In simple terms, blending is the process of combining two or more materials to achieve a desirable property.
Why Fibre Blending is Necessary?
The most popular reason for blending is that of combining the properties of two or more fibers. Blending of different fibers is also used to increase aesthetic effects in the fabric.
Polyester/cotton blend is an example; a good end use is in suiting. Polyester is a man-made fiber with high abrasion resistance and cotton is a natural fiber and has good moisture absorbency & feel.
What is CVC Yarn?
In a cotton-polyester blended yarn, when the amount of cotton fibre is more than polyester fibre it is called CVC yarn. Here CVC stands for Chief Value of Cotton i.e., the ratio of cotton fibre is always above 50% or more.
Example: 30 s/1 Ne (60/40) CVC Yarn means, It is a 30 count single ply cotton-polyester blended yarn where the ratio of cotton fibre to polyester fibre is 60 to 40.
What is PC Yarn?
A cotton-polyester fibre blended yarn is called PC yarn, but in general where the amount of polyester fibre is more than cotton fibre is called PC yarn. Here PC stands for Polyester Cotton.
Example: 30 s/1 (60/40) Ne PC Yarn means, It is a 30 count single ply cotton-polyester blended yarn where the ratio of polyester fibre to cotton fibre is 60 to 40.
It can be said that every CVC yarn is also PC yarn but all the PC yarns are not CVC yarn.
Blending Process of Cotton-Polyester Fibre
To produce a CVC/PC yarn the fibres must be blended before it reaches to ring frame machine as roving. This blending process mainly can be done in two manners.
1. Fibre Blending
According to the blending ratio of cotton & polyester fibre in the yarn, numbers of cotton & polyester bales are given in the laydown in blowroom using bale management.
The homogenous blending of fibres takes place at mixing machine- mostly used as- Unimix (Rieter) or Multimixer (Trutzschler) machine. This type of mixing/blending is called fibre blending.
From this type of blending, blended card slivers can be obtained. Then the regular spinning flow chart is followed till ring frame machine to produce PC/CVC blended yarn.
2. Sliver Blending
In this process, cotton fibres & polyester fibres are processed through separate machines from blowroom to carding. Then the separate card slivers are made from polyester & cotton.
After that, to ensure better blending, the polyester carded slivers are passed through one phase draw frame which is known as pre-pass phase to keep the sliver hank as optimum as possible.
Then, according to the required blended ratio the slivers are blended in breaker draw frame. In draw frame slivers are doubled, drafted & blended to the required ratio.
Finally, conventional spinning process is followed till ring frame machine to produce PC/CVC yarn.
Which Type of Blending is Better?
After a lot of experiments, it has been noticed that sliver blending is slightly better than fibre blending.
That is because, in sliver blending, the ratio of cotton & polyester can be maintained more precisely than fibre blending.