What is slub in Fabrics?
Slub refers to an uneven thickened area (nubby areas) in a yarn that gives the fabric it is made of, an irregular-textured appearance.
Slub yarns are considered fancy spun yarns with uneven thickness with thick and thin sections appearing along its length regularly or irregularly. The thickened place in the yarn may be many times bigger than the normal yarns. The fabrics made using the slub yarns are called slub fabrics.
Slubs on fabric may be appreciated for their special texture; but where this texture is not needed, they may result in the rejection of the fabric. The slubs may be considered a fabric defect and slub yarns are considered inferior.
Slub yarns may be used as filling thread in weaving fabrics. The Slub texture is appreciated in silks, suiting and upholstery fabrics because of the character the texture gives to the fabrics.
All raw silks have slub yarns – they are pure silk made from silk yarns with inherent imperfections. These fabrics have a crisp hand. Silk Shantung is a material with slub yarns producing an attractive textured appearance. You can find slubs in common fabrics like Denim.
Slub yarns may be produced naturally as in the case of silk yarns or due to a fault in the spinning process or by deliberately producing irregularities in its construction. The irregularities are introduced during the spinning of the yarn by changing the speed of the bottom rollers on the spinning frame.