| 摘要 |
PROBLEM TO BE SOLVED: To improve the softness and the durability and to effectively remove dental plaque by determining a diameter of a tip of a tapered bristle relative to the bristles of a toothbrush. SOLUTION: A polyethylene bristle is cut by a desired length, and the cut bristles are vertically dipped into a strong alkali or acid solution by a length less than 10 mm from one end thereof to dissolve the bristles so that a taper having 0.10 mm-0.15 mm of a diameter of a tip of the bristle is formed in a state that the length of the bristle is not changed or slightly elongated. Then the treatment same as that for one end of the cut bristles, is performed on the other end of the cut bristle by the length less than 10 mm, the bristles having the taper are washed with the water and dried, a plurality of bristles are buried in a point part of a handle of a toothbrush, and the taper is formed by the time when a diameter of the bristles for forming a toothbrush becomes 0.04 mm-0.08 mm to form the roundness. |
