General chemical fiber (polyester, acrylic, spandex, etc.) fabric will pilling ~ like some sweaters will pilling, because there are components of acrylic fiber, static electricity is also caused by these chemical fiber ~!
If it is pure cotton, it is generally not easy to pilling, and sometimes mixed with other fibers, it is easy to pilling.
Generally blended fabric is easy to pilling. For example, polyester cotton fabric, if the proportion of polyester and cotton is not reasonable, long after wearing, it will easily pilling. And acrylic fabric used to make sweaters, too long for a long time.
