Stay Tape

Definition and Overview

Stay tape is an auxiliary material used to reinforce areas of textile that tend to stretch along the grain or bias direction and to stabilize dimensions and shape. Some types are sewn onto the seam allowance side, while others are attached with adhesive.

Its purpose is not to make the textile itself stiff, but to suppress stretch only in the necessary areas. The type of tape and how it is used are determined according to the outer fabric's thickness, stretch, and sewing specifications.

Areas of Use and Role

Typical application areas include shoulder seams, necklines, front edges, pocket openings, armholes, crotch seams, and zipper openings. These are areas that are likely to stretch or ripple due to cutting, sewing, or wear.

In knits and stretch wovens, it is used to prevent shoulder seams from dropping and necklines from opening out. On the other hand, if it is fixed too firmly even in areas that require movement, it may impair wearing comfort and the seam's ability to follow movement.

• Shoulder seams: suppress shoulder droop and seam stretch.
• Necklines and armholes: suppress stretch and rippling in curved areas.
• Front edges and openings: stabilize the shape of plackets, zipper areas, and similar parts.
• Pocket openings: suppress opening stretch caused by repeated use.

Types and Cutting Direction

The amount of stretch in tape differs depending on the weave or knit structure and the cutting direction. In general, straight-cut tape aligned with the grain is better at limiting stretch, while bias-cut tape is easier to follow curves.

Adhesive types can be temporarily fixed with an iron or press, making them easy to use for reducing shifting during sewing. Non-adhesive types are sewn in place and are considered for fabrics that are weak to heat or specifications that need to avoid the effects of adhesive.

• Straight cut: suitable for straight sections and areas where stretch should be especially limited.
• Bias cut: suitable for following curves such as necklines.
• Adhesive type: used in specifications where sewing is done after attaching.
• Non-adhesive type: used in specifications where the tape is sewn in or sewn on.

How to Choose and Precautions for Adhesion and Sewing

Choose the width according to the seam allowance width, the range to be reinforced, and the sewing position. If the tape is too wide, excess stiffness may appear; if it is too narrow, stability may be insufficient. Tape that stretches more than the outer fabric is not suitable for stay tape applications.

For adhesive types, test them in the actual layered condition including the outer fabric, and confirm the bonding conditions such as temperature, pressure, and time. Also check for problems such as fabric shrinkage after bonding, fading on the surface, or peeling.

During sewing, it is important not to sew while pulling the tape and fabric. In particular, on curves, excessive easing of the tape can cause rippling and puckering in the finished seam, so the fixing method should be considered in advance according to the specification.

Differences from Similar Terms

Stretch tape uses elasticity to provide movement and fit. Its purpose differs from stay tape, which suppresses stretch, so stretch tape should be considered in areas where a required level of extensibility is needed.

Bias tape is also used for finishing fabric edges, decoration, and visible specifications such as piping. Bias-cut stay tape has the common advantage of following curves easily, but its main purpose is shape stabilization rather than edge finishing.

Fusible interlining is also an auxiliary material that gives fabric body and stability, but it reinforces a certain area. Stay tape differs in that it locally reinforces linear areas such as seams and edges.

Frequently Asked Questions

What kind of stay tape is used for shoulder seams in knits?

For shoulder seams, a straight-cut tape with low stretch is generally used. However, on lightweight knits, the tape's thickness and stiffness may show through on the surface. Check the outer fabric's stretch, seam allowance width, and post-wash condition, and verify with a sample whether there is any drooping or puckering.

Can adhesive stay tape be used without sewing?

Whether it is used only with adhesion or sewn in after adhesion depends on the area and the specification. For areas that receive load or products that are washed repeatedly, do not rely only on adhesive strength; consider fixing it by sewing as well. Always confirm the bonding conditions and durability with the actual fabric.

Can straight-cut tape be used on a neckline?

If straight-cut tape is used on a curve such as a neckline, the tape may not settle well and can cause puckering or rippling. Depending on the degree of curve, the stretch of the outer fabric, and the specification, choose bias-cut tape or a tape designed for curves, and it is important to do a partial test seam.