Method for manufacturing interdental cleaning device

1. A method for manufacturing an interdental cleaning device including:

a base portion that is formed by molding a synthetic resin material and includes a handle portion and a core portion provided at a front end of the handle portion and having a slender shaft shape; and

a soft portion that is formed on the base portion by molding an elastomeric material, and includes a cleaning soft portion substantially covering at least part of the core portion, a non-slip portion substantially covering at least part of the handle portion, and connecting portions also covering at least part of the handle portion, extending from two sites of the non-slip portion, and being connected to the cleaning soft portion,

the method comprising:

forming, in the base portion, a concave portion so as to correspond to the non-slip portion, and a groove so as to correspond to each of the connecting portions;

providing, in a mold, a plurality of molding spaces in parallel for molding soft portions including the soft portion;

providing a gate of a mold, which opens to each of the plurality of molding spaces, to open at a mating surface of the mold, and open at a position substantially equally distant from positions of two communicating openings of a non-slip molding space for molding the non-slip portion, the two communicating openings communicating with connecting portion molding spaces for molding the connecting portions; and

charging the elastomeric material from the gate into a soft portion molding space to fill the soft portion molding space.

2. The method according to claim 1 , wherein the connecting portion molding spaces are located to connect and communicate with two sites that are substantially symmetrically apart by substantially 180 degrees in a circumferential direction about a central axis of a cleaning soft portion molding space for molding the cleaning soft portion.

3. The method according to claim 1 , wherein

the mold has a cleaning soft portion base end portion molding space that is for molding a loop-shaped cleaning soft portion base end portion and is located at a base end of the cleaning soft portion molding space, and

the connecting portion molding spaces are located to connect and communicate with two sites of the cleaning soft portion base end portion molding space.

4. The method according to claim 1 , wherein

the handle portion is formed in a substantially flat rod shape,

the connecting portion molding spaces are placed at positions facing both wide surfaces of the handle portion, and

the opening of the gate is placed at a position facing a narrow surface of the handle portion.

5. The method according to claim 1 , wherein

the mold has a plurality of molding spaces arranged in parallel each for molding the soft portion,

the mold has a common supply channel for supplying the elastomeric material to both of adjacent non-slip portion molding spaces, which constitute a pair of two of the molding spaces arranged in parallel, the common supply channel extending to a substantially central position between the adjacent non-slip portion molding spaces,

the mold has individual supply channels that are branched from the substantially central position and formed to reach openings of the gates formed at opposed positions of the respective non-slip portion molding spaces, and

the elastomeric material is charged into each of the molding spaces through the common supply channel and the individual supply channels so that soft portions including the soft portion are simultaneously molded on a plurality of base portions including the base portion.

6. The method according to claim 1 , wherein a region having a through or bottomed hole is provided on the handle portion in a range from a base end side to a non-slip portion-covered region.