Surface Distortion
Longitudinal creases or streaks formed on the fabric surface when it is processed in a bundled or rope-like form during dyeing or washing. These permanent distortions occur when the fabric remains in the same folded position under heat and pressure for an extended period. They are particularly common in jet and winch dyeing machines where the fabric is not held at full width.
Preventing rope marks is a major concern when processing synthetic or tightly woven cotton fabrics.
Formation Mechanism
If the fabric does not open up and redistribute its folds during the cycle, the chemicals and heat fix the creases into the fiber structure. These lines are often visible as lighter or darker bands because the dye penetration is uneven in the compressed areas. Cooling the dyebath too quickly at the end of the cycle can also lock these distortions in place.
Remedial Actions
Using crease-inhibiting agents in the liquor helps the fabric slide more easily and prevents tight folds. Increasing the liquor ratio or the cloth speed can also minimize the time a single crease is held. For sensitive fabrics, processing at full width on a jig or a continuous range is the preferred alternative.
Inspection Criteria
Quality auditors check for these marks under flat lighting where the shadows cast by the creases are most apparent.
