Peel Strength

Definition and Overview

Peel strength is an indicator used to evaluate how securely the adhesive resin of fusible interlining is bonded to the outer fabric. It is checked by pulling one end of a bonded sample as if peeling it back to confirm how resistant it is to separation. The higher the value, the greater the force generally required to peel off the adhesive layer.

However, peel strength alone cannot determine whether an interlining is good or bad. It is important to check the balance with the performance required of the product, including the hand of the outer fabric, stretch, thickness, sewing properties, and appearance after washing.

Areas of Use and Role

Fusible interlining is used in areas such as collars, front facings, cuffs, facings, pocket openings, and the waist area, where shaping or stretch control is needed. In these areas, force is applied to the edges through bending during wear or handling during sewing, so peel strength suited to the application is required.

In particular, at places such as collar points, front edges, and cuff ends, where the edge of the fusible interlining is folded together with the outer fabric, insufficient bonding is more likely to appear as lifting or peeling. On the other hand, excessive bonding strength may make the outer fabric look stiff or impair its hand.

Differences by Material and Type

Fusible interlining includes nonwoven interlining, woven interlining, and knitted interlining, and adhesion performance and finish vary depending on the structure of the base fabric, the type and amount of resin, and the shape of the dots. Nonwoven interlining makes it easier to provide stability, while woven and knitted interlining may be selected to match the hand and stretch of the outer fabric.

The outer fabric also affects adhesion. Not only the type of fiber, but also the weave or knit structure, brushing, treatments such as water repellency, and surface irregularities change how the resin makes contact. Even with the same interlining, peel strength and appearance change if the outer fabric changes.

Selection and Bonding Conditions

Select interlining to match the thickness, firmness, stretch, and sheerness of the outer fabric, avoiding anything that is extremely thicker, stiffer, or heavier than the outer fabric. For thin or soft outer fabrics, check whether hardening after bonding, resin bleed-through, or surface irregularities become noticeable.

Peel strength is affected not only by the choice of interlining, but also by the temperature, pressure, time, and cooling conditions of the fusing machine. If the resin cannot melt and penetrate sufficiently, bonding will be insufficient; if the temperature is too high or the pressure too strong, there is a risk of glossing, 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 simulated washing or cleaning.
• Recheck as needed when the outer fabric differs in color, finish, or lot.

Sewing Considerations and Differences from Similar Terms

Bonding defects may appear as lifting between the outer fabric and interlining, called bubbling, or as peeling at the edges. Because there are also steps in sewing that apply heat and steam with an iron or press, confirm along the process whether reheating after bonding changes the appearance or bonding condition.

Peel strength is the 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 achieve good adhesion, and peel strength is one of the items used to evaluate the result. Bubbling, meanwhile, is a visual phenomenon caused by bonding defects and is not the strength itself.

Frequently Asked Questions