Examples of' the potentially adhesive fibers are thermoplastic fibers, such as those of cellulose acetate or other cellulose esters and ethers, or mixed cellulose esters such as cellulose a'cetate-propionate, or cellulose acetate-butyr-ate, in plas- V ticized condition; also resins'as, for example, cheap natural resins such as shellac, dammar, copal and the like, and synthetic resins either perma