Fusing Conditions

Definition and Overview

Fusing conditions are the process settings used to fix fusible interlining, which has heat-meltable adhesive resin, to the shell fabric. They are mainly controlled by the temperature, pressure, and pressing time of the press, and sufficient cooling after fusing also affects finish stability.

Even with the same fusible interlining, the proper conditions vary depending on the shell fabric's fibers, weave, thickness, finish, color, and other factors. It is important to use the recommended conditions shown in the interlining specification sheet as a baseline and to test on the actual shell fabric before mass production.

• Temperature: the temperature of the press surface used to properly melt the adhesive resin.
• Pressure: the force that brings the interlining and shell fabric into close contact and helps the resin bond to the textile side.
• Time: the duration of applying temperature and pressure; too short or too long both cause problems.
• Cooling: the process of stabilizing the resin after fusing, and care is needed when handling it before it has fully cooled.

Areas of Use and Role

Fusing conditions are managed when fusible interlining is used for areas that need to hold their shape, such as collars, front facings, cuffs, facings, pocket openings, and waist belts. They help stabilize the required firmness, recovery, and ease of handling during sewing.

In jackets and coats, interlining may be fused over a wide area such as the front body and lapels. On the other hand, for thin shirts and blouses, it is necessary to avoid excessive heat and pressure, prioritizing preservation of the shell fabric's softness.

Settings According to Interlining and Shell Fabric

Fusible interlining includes nonwoven interlining, woven interlining, knit interlining, and others, and the stretch, thickness, adhesive resin type, and coating condition of the base fabric differ. Therefore, even interlining that looks the same cannot be treated with a single set of fusing conditions.

For compatibility with the shell fabric, check the thickness, firmness, stretch, surface texture, fuzzy finish, water-repellent finish, and other processing of the shell fabric. For thin fabrics or heat-sensitive materials, pay attention to glossing and shrinkage, and for stretch materials, consider interlining and conditions that do not interfere with the shell fabric's stretch.

When selecting interlining, check not only the firmness after fusing but also the shell fabric's texture, drape, and condition after washing. If the interlining is too firm compared with the shell fabric, it may cause puckering around seams or an unnatural stiffness.

Points to Note in Fusing and Sewing

If the temperature or time is insufficient, poor bonding or insufficient peel strength may occur. Conversely, if the conditions are too strong, adhesive bleed-through, glossing of the shell fabric, shrinkage, discoloration, and hardening of the hand may result.

After fusing, do not judge by appearance alone; also check the bonded condition including the edges, durability assuming washing or cleaning, and lifting when bent. Bubbling is a phenomenon in which lifting or a bubble-like appearance occurs between the shell fabric and the interlining, and it can be caused by unsuitable conditions or material incompatibility.

During sewing, pay attention to thickness differences between fused and non-fused areas, needle holes, and seam slippage. Because the fused area may be reheated during the pressing process after sewing, it is necessary to determine the conditions while considering the heat history of the entire process.

Differences from Similar Terms

Fusible interlining refers to the interlining itself that is bonded to the shell fabric for reinforcement or shaping, while fusing conditions refer to the process settings used to bond it. Haircloth interlining and non fusible interlining are often used with stitching or temporary fixing, and their usage differs from fusible interlining, which assumes heat bonding.

Peel strength is an evaluation item that shows how difficult it is for the fused interlining to peel away from the shell fabric. Fusing conditions affect peel strength, but the combination of interlining and shell fabric, the adhesive, and post-processing or washing conditions also affect the evaluation results.

Frequently Asked Questions

Are there no problems if fusing conditions follow the recommended values for the interlining?

The recommended values are useful as a starting point for settings, but the finish will vary depending on the combination with the shell fabric and the condition of the press. Before mass production, perform trial fusing with the actual shell fabric and interlining, and determine the conditions after checking the appearance, hand, peeling, and condition after washing.

How do you check bubbling, where the interlining lifts after fusing?

Observe the fused area on a flat surface and shine light from an angle to check whether there is any local lifting or waviness. It is also effective to bend it lightly by hand or check the edges. When it occurs, review not only temperature, pressure, and time, but also the compatibility between the shell fabric and the interlining.