Stiffness
Stiffness is a property that indicates the degree of resistance when textile or interlining is bent, and it is an indicator related to a garment’s firmness, how well it holds its shape, and ease of movement when worn.
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Definition and Overview
Stiffness is a property that indicates how difficult a material is to bend, or how flexibly it bends. A material with high stiffness has greater resistance to bending, while one with low stiffness tends to bend more easily. In interlining, it is an important factor when considering the three-dimensional effect and resilience it gives to the outer fabric.
Stiffness is not determined by thickness alone. It is affected by a combination of factors such as fiber type, weave, density, resin finishing, and the amount of adhesive resin. Even at the same thickness, bending and recovery differ depending on the structure, such as woven interlining, nonwoven interlining, or knit interlining.
Application Areas and Roles
Interlining is used in collars, front plackets, cuffs, facings, and the waist area to supplement the shape retention that the outer fabric alone may lack. Stiffness is used to adjust collar stand, front edge straightness, cuff firmness, and the stability of facings.
In jackets and coats, the stiffness of the interlining used around the chest, lapels, and front body affects the outline and tailoring appearance. On the other hand, for blouses and lightweight garments, it is important to avoid excessively stiff interlining so as not to impair the lightness or drape of the outer fabric.
- Collars and cuffs: maintain shape while considering comfort against the neck and wrists.
- Front plackets and facings: suppress waviness and stretching at the front edge, and stabilize the opening.
- Waist area: as waistband or waist interlining, maintain dimensions and shape.
- Chest area: add body and resilience, and refine the garment outline.
Differences by Material and Type
Nonwoven interlining is a sheet-like interlining made by entangling fibers, and some types show relatively little directional difference. Woven interlining has a woven structure, so bending and stretching may differ between the warp and weft directions, and cutting with attention to the grain line is necessary.
Knit interlining blends well with stretch outer fabrics and is used for applications that require responsiveness to movement. Haircloth interlining is a tailoring interlining made with wool and other materials; unlike fusible interlining, it may be shaped into a three-dimensional form by sewing and basting.
Selection and Precautions for Bonding and Sewing
Select interlining that balances with the thickness, firmness, stretch, and surface texture of the outer fabric. If interlining with excessive stiffness is fused to a thin, soft outer fabric, it may result in a hard impression, lifted edges, or an unnatural surface. Conversely, if the interlining is too soft, the necessary shape retention cannot be achieved.
For fusible interlining, check not only stiffness but also the bonding conditions. If temperature, time, or pressure is not appropriate, peeling, bubbling, or strike-through may occur. Before full production, perform trial fusing using the outer fabric and interlining, and check the appearance, firmness, and bond condition after washing or dry cleaning.
During sewing, adjust the needle, thread, and sewing conditions to match the thickness and firmness of the overlapped interlining areas. Forcing a hard interlining through sewing can cause puckering and visible needle holes. It is necessary to process according to the specification, such as reducing seam overlap or cutting away the interlining where needed.
Differences from Similar Terms
Body and resilience are texture terms that describe the firmness and springiness felt in a fabric. Stiffness is a property that mainly focuses on resistance to bending; the two are related, but not the same. Even if a fabric feels firm, the way stiffness appears differs depending on the bending direction and material structure.
Fusible interlining, haircloth interlining, woven interlining, and knit interlining are names for types of interlining. Stiffness, by contrast, indicates the degree of resistance to bending that these interlinings or outer fabrics have. When selecting interlining, check not only the type but also the stiffness and how well it blends with the outer fabric.
Frequently Asked Questions
If I choose interlining with high stiffness, will the collar shape stay neat?
It helps with shape retention, but higher is not always better. If the interlining is too stiff compared with the outer fabric, problems such as lifted collar edges, unnatural folds, or discomfort against the neck during wear may occur. Confirm with trial fusing and sewing samples using the outer fabric.
Is thick interlining always high in stiffness?
Not necessarily. Thickness is one factor that affects resistance to bending, but differences also arise from material, fiber density, structure, resin finishing, and stretch. Rather than judging by thickness alone, it is important to check the actual bending feel and the appearance of the outer fabric after bonding.
Can stiffness change after bonding?
Yes. By bonding the outer fabric and interlining with adhesive resin, the resistance to bending and the resilience change from the state of each material alone. Since the finish also varies depending on pressing conditions and the composition of the outer fabric, evaluate samples bonded under the specified conditions and adjust the conditions if necessary.
