Sea island yarn for suede fabric is not a single butterfly yarn. It is actually a composite ultra-fine mixed yarn that is processed by interlacing process after the combination of ordinary sea-island yarn and high-shrinkage yarn. Our company supplies the polymer (alkali-soluble PET chip and high shrinkage PET chip) for these two kinds of yarn spinning. That’s to say, sea island yarn for suede fabric is a combination of sea-island fiber, composite fiber, mixed fiber, and interlaced yarn. However, in the actual production, we still call “Sea Island Yarn for Suede Fabric” in short of “island yarn”.
The sea-island yarn floats on the surface of the fabric with a larger floating length. After being opened by the action of lye, the fixed state of the high-shrinkage yarn is released and shrinkage occurs. Then the sea component of the sea-island yarn is dissolved, and island fibrils are loosely entangled around highly contracted filaments. Island fibrils are composed of ultra-fine fibers. Although its fiber-specific strength is large, the fiber diameter is very fine and the absolute strength is low.
Therefore, under the same conditions, the island fibrils are more likely to be worn off than other fibers, resulting in many fine and even fluffy clusters on the surface of the fabric. We can see more information from the below picture.
The determinants of the length of sea-island velvet hair are sea-island silk floating length, fabric structure, warp and weft density, warp and weft thread density, the shrinkage rate of high shrinkage yarn in composite yarn, the absolute strength of superfine fiber, and the sanding process.
At the same time, the length of the fluff also depends on the stability of the sea-island silk in the fabric. The tighter the fabric, the less slippage of the threads and fibers, the easier the sanding, the shorter the obtained fluff, and the more uniform and fine fluff clusters. Conversely, the looser the fabric, the easier it is for the threads and fibers to slip, and the more difficult it is to grind the pile. The longer the piles are obtained, the more messy and rough pile clusters are.
The length of suede fleece is also affected by the opening rate during stenter setting. The larger the opening rate, the larger the width of the weft under the same circumstances, and the longer the fluff formed after sanding.