Material Defect
Unreactive polymer contaminants embedded in woven or knitted cotton fabrics create visible undyed spots after finishing. A polyolefin white speck is a physical defect that occurs when polypropylene or polyethylene fragments from packaging materials remain in the yarn. These synthetic polymers do not absorb direct or reactive cotton dyes.
The resulting uncolored spots spoil the appearance of dark fabrics.
Contaminant Source
Frayed polymer bags and woven plastic sacks used during harvesting and transport are the main sources of these contaminants. When the raw fiber is processed, these plastic sheets are torn into thousands of microscopic particles. These particles are then spun directly into the yarn.
Because they resemble cotton fibers in their raw state, they are difficult to find before dyeing.
Detection Process
Visual inspection under high-intensity ultraviolet light reveals these synthetic particles on the fabric surface. The polyolefin material fluoresces brightly, allowing operators to locate and manually remove them. Alternatively, automated cameras on the fabric inspection frame can flag their locations.
Early detection prevents the fabric from being processed into finished garments.
Production Impact
Once the fabric is dyed, removing these specks is impossible without ruining the material. Batches containing high levels of these defects are downgraded to lower value products or rejected. This leads to substantial financial losses for the finishing mill.
