A collar that looks crisp and shapely right after production can soften, collapse, or deform after several wears or washes. In many cases, the issue isn’t simply whether the interlining is stiff enough. Whether the collar shape remains durable over time is directly related to the fabric’s support, the compatibility of the collar and interlining, the fusing and pressing conditions, and changes in shrinkage after washing.

Wrinkling after fusing viscose fabric with fusible interlining is not necessarily a quality issue with the fabric. Whether the wrinkles appear immediately after pressing, or only after washing or ironing, leads to completely different diagnostic directions. The cause should not be attributed solely to the fabric.

Linings labeled with the same 80 g/m² weight, when fused to different fabrics, may result in stiff hand feel, insufficient support, post-wash wrinkling, or poor fusing adhesion. When selecting interlinings, weight only indicates the mass per unit area and cannot be directly equated to the final garment effect.

Interlining may look like just a piece of backing material with a layer of glue, but once pressed onto fabric, issues such as strike-through, stiffening, blistering, or unevenness after washing can occur. The problem is not necessarily about whether the adhesive "sticks firmly" – coating details often determine which fabric, which garment part, and which process it suits.

In the garment industry, terms like "softer," "firmer," "with bone structure," and "not stiff" actually correspond to different handle requirements for interlinings in different parts of a garment. The collar, placket, front panel, and waistband cannot use the same interlining; if matched incorrectly, it can easily lead to stiffness, collapse, post-wash wrinkling, or unnatural garment lines.

For summer women's wear, lightweight fabrics often lead to issues such as a non-crisp placket, collar collapse, and wrinkling after washing. These are often related to the choice of interlining and the control of the fusing process. Judging whether an interlining is suitable cannot rely solely on its hand feel (soft or hard); it must be evaluated in combination with the fabric's characteristics, the application area, and post-production testing.