For downs used for filling down products such as down comforters/quilts and down jackets, plumage of water birds is used in general. Examples of water birds include a goose, a duck and an eider (wild duck) that inhabits coastal areas around the Arctic Circle. The plumage is classified into down that covers the breast of a bird and feather, both of which are used for down products. Such plumage is produced in Central Europe such as Poland and Hungary, Northern Europe including the Scandinavian Peninsula, China and the like. Down is bulky and warm, and thus it is highly prized as a high-class material for down products like comforters/quilts and down jackets.
However, as the supply of natural plumage depends on water birds, the supply is limited and furthermore, the supply fluctuates under the influences of natural conditions and/or disasters and diseases (e. g., avian viruses). Also, capture of wild birds is limited from the viewpoint of protecting the natural environment. In addition to that, natural plumage will have an offensive odor if it is washed insufficiently. Therefore, it is required that dirt causing a bad smell be removed in advance and the plumage is kept under control for maintaining a certain level of cleanliness and oxygen count. A further problem is that such products of plumage like a down comforter/quilt and a down jacket cannot be washed easily.
In light of such problems, many proposals have been made for the wad. Patent document 1 proposes bending staples to be looped and fixing the staples at any overlapping points. Patent document 2 proposes air-entangling a core fiber and a loop fiber by use of an air nozzle and then fusing the fibers. Patent document 3 proposes shrinking a polyester fiber by heating so as to develop crimping, thereby providing the fiber with bulkiness and elasticity. Patent document 4 proposes binding untwisted staples with low-melting-point fibers and fusing. The Applicants propose in Patent document 5 a wad composed of a core yarn and an effect yarn, in which the core yarn is fused.