Peel Strength

Definition and Overview

Peel strength is an indicator used to evaluate how firmly the resin in a fusible interlining adheres to the outer fabric. A bonded sample is pulled as if peeling up one end, and resistance to peeling is checked. The higher the value, the greater the force generally required to peel off the adhesive layer.

However, interlining quality cannot be judged by peel strength alone. It is important to check the balance with the performance required of the product, including the outer fabric’s hand, stretch, thickness, sewing properties, and appearance after washing.

Parts Used and Their Role

Fusible interlining is used in areas that shape the garment or reduce stretch, such as collars, front plackets, cuffs, facings, pocket openings, and the waist area. In these areas, forces are applied to the edges through bending during wear and handling during sewing, so peel strength suited to the application is required.

In particular, in areas such as collar points, front edges, and cuff ends, where the edge of the fusible interlining is folded together with the outer fabric, insufficient adhesion is more likely to appear as lifting or peeling. On the other hand, excessively strong adhesion may make the outer fabric appear stiff or damage the hand.

Differences by Material and Type

Fusible interlining includes nonwoven interlining, woven interlining, and knit interlining, and adhesion performance and finish vary depending on the base fabric structure, resin type and add-on amount, and dot shape. Nonwoven interlining tends to provide stability, while woven interlining and knit interlining may be selected to match the outer fabric’s hand and stretch.

The outer fabric also affects adhesion. Not only the fiber type, but also the weave or knit structure, finishing such as fuzzy or water repellency, and surface unevenness change the state in which the resin contacts the fabric. Even with the same interlining, peel strength and appearance change when the outer fabric changes.

Selection and Bonding Conditions

Select interlining so it is not extremely thicker, stiffer, or heavier than the outer fabric, and match it to the outer fabric’s thickness, firmness, stretch, and sheerness. For thin or soft outer fabrics, confirm that hardening after bonding, resin strike-through, and surface unevenness will not stand out.

Peel strength is affected not only by the choice of interlining, but also by the bonding machine’s temperature, pressure, time, and cooling conditions. If the resin cannot be sufficiently melted and penetrated, adhesion will be insufficient, while excessive heat or pressure may cause shine, shrinkage, or changes in hand.

• Before mass production, create a bonding sample using the actual outer fabric and interlining.
• Check not only immediately after bonding, but also after cooling, after sewing, and after expected washing or dry cleaning.
• For different colors, different finishes, or different lots of the outer fabric, recheck as needed.

Sewing Precautions and Differences from Similar Terms

Bonding defects may appear as bubbling, where the outer fabric and interlining lift, or as peeling at the edges. Because sewing processes may also involve heat and steam from an iron or press, confirm in sequence whether reheating after bonding changes the appearance or bonded condition.

Peel strength is performance against force applied in the direction of peeling the bonded surface. Bonding conditions refer to the temperature, pressure, time, and similar settings used to obtain good adhesion, and peel strength is one of the items used to evaluate the result. Bubbling, on the other hand, is an appearance defect caused by poor bonding and is not strength itself.

Frequently Asked Questions

Is fusible interlining always good if peel strength is high?

No. Even if peel strength is high, it is not suitable if the outer fabric becomes stiff, bonding marks appear, or fading appears on the surface. Evaluate appearance after bonding, sewing properties, and post-wash condition comprehensively, based on the outer fabric’s hand and the intended use.

What should be checked if fusible interlining peels off?

First, check the combination of interlining and outer fabric, the bonding machine’s temperature, pressure, time, and the cooling process. The outer fabric’s finish and surface condition, as well as the storage condition of the interlining, also affect the result. It is effective to make a bonding sample and compare whether peeling or lifting occurs immediately after bonding, after cooling, and after later processes.