The following is information provided by Quilters Dream Cotton Batting. Static can cause batting to beard through dark fabrics. According to researchers, manufacturers of dark fabrics use sulfur in the dying process which, under certain conditions, may cause a static charge. The sulfur is a penta-valent, or five sided, molecule which is an electrical attractant. This holds the dye firmly to the fabric but also may also affect batting fibers.
Cotton is cohesive and naturally non-bearding.
However, just as static electricity will cause your hair to stand on end, the same can happen to cotton and other fibers. Very lightly mist cotton batting with a water sprayer, dry on very low heat with an anti-stat dryer sheet. If you feel you must, use antistatic bags.