Reposted: A Precise Analysis of the Causes of Pilling in Cashmere Apparel

Even the highest‑quality cashmere garments may exhibit slight pilling when first worn; therefore, national standards stipulate that as long as the pilling grade of a cashmere sweater remains within the permissible range, it is considered a合格 product.

So, why do cashmere garments develop fuzz and pill?

First, it is related to the characteristics of cashmere fibers.

First, compared with wool, cashmere fibers are finer, shorter, and have fewer crimps, resulting in weaker cohesion within the yarn and a greater proportion of loose fibers exposed on the surface. Coupled with their smooth, slippery texture, these fibers readily slip out of the fabric under external forces, leading to shedding and pilling. Moreover, because the surface of cashmere fibers is densely covered with scales, when the fiber bundle is subjected to random external forces, fibers oriented against the scale direction tend to migrate toward the root, creating a directional friction effect that exacerbates shedding. At the same time, the interlocking between scales and the elasticity of the fiber body cause the fibers to become entangled and form pills, resulting in the characteristic felting and shrinkage typical of animal fibers.

Secondly, cashmere fibers have poor electrical conductivity. During wear, friction between the fibers causes charges to accumulate within them, resulting in static electricity. Fibers with a high dielectric constant tend to acquire a positive charge, while those with a low dielectric constant acquire a negative charge. For example, when synthetic fibers rub against cashmere, the synthetic fibers become negatively charged, whereas the cashmere fibers become positively charged. Oppositely charged fibers attract one another, which can lead to fiber shedding and pilling; this effect is particularly pronounced in dry conditions.

Furthermore, the more pronounced the crimp in the fibers, the less readily they elongate under twist; during friction, the fibers tend to loosen and slip, leading to a fuzzy surface on the yarn. Consequently, the greater the fiber crimp, the more prone the yarn is to pilling. Similarly, finer fibers expose a larger number of fiber ends at the yarn surface and exhibit greater softness, making them more susceptible to entanglement and pilling than coarser fibers. As for fiber length, shorter fibers are more likely to pill than longer ones, owing to the higher proportion of free ends and the reduced friction and cohesion between short fibers, which allow them to migrate to the fabric surface and readily form pills.

In addition, the twist level and surface smoothness of the yarn significantly influence pilling. Yarns with higher twist exhibit tighter fiber interlocking; when subjected to friction, fibers are less likely to slip within the yarn, thereby reducing pilling. However, since cashmere garments are soft textiles, excessively high twist can make the fabric stiff, so increasing twist alone cannot effectively prevent pilling. As for surface smoothness, the smoother the yarn, the shorter and sparser its surface fuzziness, making smooth‑finished yarns less prone to pilling.

Second, it is related to the fabric’s structural configuration.

Fabrics with a loose structure are more prone to pilling and fuzzing than those with a tight structure. When tightly structured fabrics come into friction with external objects, they generate less fuzz; moreover, any existing fuzz is less likely to migrate to the fabric surface due to the greater frictional resistance between fibers, thereby reducing pilling and fuzzing. Fabrics with lower density are more susceptible to pilling and fuzzing than those with higher density. Smooth‑surfaced fabrics are less likely to pill or fuzz, whereas fabrics with uneven, textured surfaces are more prone to these defects.

Third, it is related to the influence of dyeing and finishing processes.

After yarns or fabrics have been dyed and finished, their resistance to pilling is significantly affected; this depends on the dye, auxiliaries, and the conditions of the dyeing and finishing processes. Yarns dyed in hanks are more prone to pilling than those dyed from loose fibers or slivers, while fabrics dyed as finished garments tend to pill more readily than those woven from yarns that were dyed beforehand. Furthermore, once a fabric has undergone setting—particularly resin finishing—its resistance to fuzzing and pilling is markedly improved.

Fourth, it is related to the influence of wearing conditions.

During wear, cashmere garments experience friction from outer layers such as coats, causing the shorter ends of the yarn fibers to slip out and become entangled on the fabric surface, forming pills. Moreover, cashmere fibers are finer and shorter than wool fibers, and since most cashmere sweaters are combed‑carded products with a higher proportion of short fibers in the yarn, they are even more prone to pilling.

Therefore, when wearing cashmere garments as inner layers, it’s best to pair them with outerwear that has a smooth lining—avoid anything too rough or stiff—and refrain from stuffing the inner pockets with hard objects to prevent localized friction and pilling. When worn as outerwear, avoid prolonged rubbing between the sleeves and tabletops, the sleeves and sofa armrests, or the back and sofa surfaces. Also, don’t wear these items for extended periods; be sure to alternate and rotate their use to allow the fibers to regain their elasticity and prevent fatigue‑induced damage.

Once pilling appears on cashmere garments, avoid pulling or tugging at the pills with your hands. The proper approach is to trim the pills off with scissors after washing; with a few subsequent washes, as loose fibers shed, the pilling will gradually diminish.