Bare Yarn
Bare yarn is a polyurethane elastic yarn used without being covered by other fibers, and it is a yarn used to give fabric and knitted fabric stretch and recovery.
Contents6 sections
Definition and Overview
Bare yarn refers to an elastic yarn generally made of polyurethane that is used on its own without covering. By knitting it together with the ground yarn of knitted fabric or weaving it in, it gives the material stretch and recovery.
Bare yarn is not a fabric name; it is the name for yarn used to create stretch. Even for fabrics labeled as containing polyurethane in the blend ratio, some use bare yarn while others achieve stretch by a different method, so the specifications must be checked separately.
Features and Appearance
It can provide stretch with a small amount of use, creating a fit that follows body movement. Bare yarn itself is thin and usually hidden between the ground yarns, so the appearance and hand of the surface are greatly affected by the combined materials such as cotton, nylon, and polyester.
Because it tries to return to its original shape after being stretched, it is effective at reducing sagging in areas such as the knees and elbows. However, the stretch rate and tightening feel vary greatly depending on how the yarn is inserted, knitting density, structure, and finishing, so performance cannot be judged by polyurethane blend alone.
Main Applications
It is used in items that need to follow the body closely, such as cut-and-sewn garments, innerwear, underwear, leggings, socks, sportswear, and swimwear. It is also used in rib knit that requires stretch, and in knitted fabrics such as bare jersey.
It is not a material limited to any season. In lightweight summer items, it is used for ease of movement and fit; in fall and winter items, it is used to reduce tightness caused by layering. However, warmth retention and moisture absorption and release are judged by the overall material composition of the fabric, not by bare yarn alone.
Selection and Handling Notes
When selecting it, check not only the blend ratio but also the required stretch direction, stretch recovery rate, fabric weight, thickness, and the hand on the skin side using the actual fabric. If the recovery is too strong for the wearing area, it can lead to a feeling of pressure, so fitting evaluation together with the pattern is important.
Polyurethane can be affected by heat, chlorine bleach, and residues of sweat and sebum, and its elasticity may decline over time. Follow the care label instructions and check dimensional change and recovery after washing. It is reassuring to carry out a preliminary test for high-temperature drying or treatments involving strong heat.
In sewing, do not pull the fabric more than necessary, and choose seams and thread that can follow the stretch. To prevent thread breakage at needle holes, seam shrinkage, and puckering, adjust needle size, thread tension, and differential feed through test stitching.
Differences from Similar Terms
Covered yarn is a yarn in which a core yarn such as polyurethane is wrapped and covered with another fiber. In contrast, bare yarn refers to elastic yarn without a covering. Covered yarn makes it easier to adjust surface hand and yarn handling, while bare yarn is used for applications where elasticity is to be expressed inside knitted or woven fabric.
Stretch is a general term for the property of fabric to extend, and the use of bare yarn is one way to achieve it. Also, bare jersey is the term for jersey knit using bare yarn, and it is distinguished from bare yarn itself, which refers to the yarn.
Frequently Asked Questions
Are bare yarn and polyurethane yarn the same?
Bare yarn generally refers to polyurethane elastic yarn that is not covered. Polyurethane yarn also includes covered yarn wrapped with other fibers, so not all polyurethane yarn is bare yarn.
Does fabric with bare yarn shrink?
The way it shrinks varies depending on the type of ground yarn, the knitting or weaving structure, dyeing and finishing, and washing conditions. Let the fabric relax before cutting, and before mass production, confirm dimensional change and stretch recovery through washing tests, then reflect the results in the pattern and specifications.
Are there any precautions when ironing fabric with bare yarn?
Since polyurethane may be affected by heat, give priority to the material label and the recommended conditions from the fabric supplier. Avoid prolonged pressing at high temperatures, use a pressing cloth, and work only after checking with scrap pieces to make sure there is no gloss, shrinkage, or loss of elasticity.
