Floss yarn bulking assembly and method

摘要

A process for manufacturing a continuous dental floss brush comprising alternating portions of thread sections which do not stretch significantly under tension and brush sections which stretch under slight tension, includes the step of coating at least the thread sections of a reverse twisted high tenacity nylon yarn with a solution of polymer in a volatile solvent, the polymer being selected from nylon, polyurethane and mixtures thereof. The thread sections of the yarn are thereafter heated to vaporize solvent therefrom while the yarn is maintained under a tension of from 0.15 to 1N. In the humidifier assembly, having a housing which defines a humidifier zone, the brush sections of the yarn are exposed to a mixture of steam and gas, the steam and gas mixture having a temperature of from 130 DEG C. and a water vapor content of 65%(v/v), while the yarn is under a tension of approximately zero until the brush sections of the yarn have regained at least 100 percent of the diameter of the uncoated, relaxed yarn. Finally the brush sections of the yarn are heated to remove solvent therefrom while the yarn is under a tension of approximately zero to form a floss brush product. As the yarn passes through the humidifier zone, the tension on the yarn is controlled to take account of changes in its length.