Toothbrush

Abstract

To provide a toothbrush which is excellent in design of a handle body and is capable of adjusting a center of gravity position without changing an outer diameter of a handle body, and a method for manufacturing the same.SOLUTION: A toothbrush includes a head part on which bristle tufts are planted, and a handle body connected to the head part. The handle body is composed of a handle body part integrally molded with the head part and a coating part coating a part or the whole of the surface of the handle body part. The coating part is a molded body of a primary molding material whose melting point or glass transition point is 150°C or higher, and the head part and handle body part are molded body of secondary molding resin.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a toothbrush including a head portion in which tufts of bristles are implanted and a handle body connected to the head portion.

Background Art

[0002] Conventionally, for example, as shown in Patent Document 1, for the purpose of providing a toothbrush that can prevent damage and breakage of the head portion and the neck portion and can be easily manufactured, a head portion in which a plurality of tufts of bristles are implanted on the bristle-implanting surface, a neck portion extending from the head portion, and a handle body including a handle portion extending from the neck portion are provided. On the surface of a base made of a hard resin of the handle body, a toothbrush is known in which a coating layer made of a soft resin covering 70% or more of the total surface area of the head portion and the neck portion is formed.

[0003] As a method for manufacturing the toothbrush, for example, a method including a molding step of molding the base of the handle body (primary molding) and forming a coating layer on the obtained base (secondary molding), and then a bristle-implanting step of implanting tufts of bristles into the head portion 2 is known.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to the conventional method for molding a toothbrush, when a coating layer is formed by secondary injection of a light-transmissive soft resin onto the base of the handle body formed by primary injection of the hard resin, small protrusions (ribs) are provided on the surface of the base to prevent warping of the base and make it easier to fix the base in the mold. However, it is not easy to adjust the ribs to a position where the base of the handle body does not move in the mold even under the injection pressure of the secondary molding resin, and there is a problem that the designability of the handle body is restricted due to the presence of the ribs. Also, in a general two-color molding method in which the coating layer is secondary molded after the base of the handle body is primary molded, when the molten secondary molding resin strongly contacts the surface of the base disposed in the secondary mold, a phenomenon (so-called, resin stealing phenomenon) occurs in which the surface of the base at the contact portion melts and the thickness is impaired, which affects the designability of the handle body of the toothbrush. When the resin stealing phenomenon is significant, there is a problem of discarding the toothbrush. In addition, the adjustment of the center of gravity position that affects the feel of using the toothbrush is carried out by changing the shape and diameter of the handle body because there is no significant difference in the specific gravity between the resins constituting the head portion and the handle body. However, since the shape and diameter of the handle body, which is the part to be gripped, also affect the feel of use, even if a shape and diameter of the handle body suitable for the feel of use are found, it has not been easy to adjust the center of gravity position to an appropriate position.

[0006] Therefore, in view of the above-described situation, the problem to be solved by the present invention is to provide a toothbrush and a method for manufacturing the same, which are excellent in the designability of the handle body and can adjust the center of gravity position without changing the outer diameter of the handle body.

Means for Solving the Problems

[0007] In view of such a situation, the present inventor has conducted intensive studies. As a result, after forming a primary molded product that becomes the covering portion of the handle body, the bed portion and the handle main body portion constituting the handle body are integrally formed using a secondary molding resin. This provides a wider range of design choices for the handle body, eliminates the need to provide ribs on the handle main body portion, and prevents problems such as flash during manufacturing. Thus, a toothbrush with excellent design can be produced. Also, by adjusting the length of the handle main body portion in the direction of the base end portion without changing the diameter of the covering portion, it was found that the center of gravity position of the toothbrush can be changed, leading to the completion of the present invention.

[0008] That is, the present invention includes the following inventions. (1) A toothbrush comprising a head portion in which a tuft of bristles is implanted and a handle body connected to the head portion, wherein the handle body is composed of a handle main body portion integrally formed with the head portion and a covering portion that covers part or all of the surface of the handle main body portion, the covering portion is a molded body of a primary molding material having either a melting point or a glass transition point of 150°C or higher, and the head portion and the handle main body portion are molded bodies of a secondary molding resin. (2) The toothbrush according to (1), wherein the primary molding material is polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene copolymer (AS resin), polystyrene (PS), polyethylene (PE), polypropylene (PP), metal, or an amorphous solid. (3) The toothbrush according to (1) or (2), wherein the secondary molding resin is a polyester-based resin or a polyamide-based resin. (4) A method for manufacturing a toothbrush comprising a head portion in which a tuft of bristles is implanted and a handle body connected to the head portion, after forming a primary molded product for the covering portion constituting the handle body using a primary molding material having either a melting point or a glass transition point of 150°C or higher, A method for manufacturing a toothbrush, characterized in that the primary molded product is mounted in a secondary mold, and a secondary molding resin is injected into a molding space of the secondary mold to integrally perform secondary molding on the head portion and a handle main body portion constituting the handle body. (5) The method for manufacturing a toothbrush according to (4) above, wherein the primary molding is selected from the group consisting of injection molding, insert molding, blow molding, extrusion molding, metal injection molding, and casting. (6) The method for manufacturing a toothbrush according to (4) or (5) above, wherein the primary molding material is polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene copolymer (AS resin), polystyrene (PS), polyethylene (PE), polypropylene (PP), metal, or an amorphous solid. (7) The method for manufacturing a toothbrush according to any one of (4) to (6) above, wherein the secondary molding resin is a polyester-based resin or a polyamide-based resin. [Advantages of the Invention]

[0009] According to the present invention configured as described above, a toothbrush having excellent design properties of the handle body and a center of gravity position adjusted to an easily grippable position in handle bodies of various designs can be efficiently obtained. [Brief Description of the Drawings]

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0011] Next, embodiments of the present invention will be described in detail based on the accompanying drawings.

[0012] As shown in FIGS. 1 and 2, the toothbrush 1 according to the present invention has a tuft base 5 having a plurality of tufting holes 20 in the head portion 2, and tufts 4 are implanted in each tufting hole 20. The toothbrush 1 of this example is a manual toothbrush including a head portion 2 on the tip side and a handle body 6 on the base end side.

[0013] The handle body 6 is composed of a handle main body portion 7 and a covering portion 8 that covers a part or all of the surface of the handle main body portion 7. The handle main body portion 7 is integrally formed with the head portion 2. The handle main body portion 7 is continuously provided on the base end side of the head portion 2, and the portion where the covering portion 8 is formed becomes the handle portion. Also, the portion between the head portion 2 and the portion where the covering portion 8 is formed becomes the neck portion.

[0014] The covering portion 8 is a molded body of a primary molding material having either a melting point or a glass transition point of 150°C or higher. In the case of a material having a melting point and a glass transition point, it refers to a material in which the lower of the two temperatures is 150°C or higher.

[0015] As the primary molding material, from the perspective that various designs can be adopted in the covering portion 8 of the handle body 6, polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene copolymer (AS resin), polystyrene (PS), polyethylene (PE), polypropylene (PP), metal, amorphous solid, etc. can be mentioned. Examples of the metal include alloy steels such as stainless steel and chrome molybdenum steel, aluminum, titanium, copper, iron, brass, etc. Examples of the amorphous solid include glass, amorphous metal, rubber, etc.

[0016] In the toothbrush 1 according to the present invention, regarding the shape of the covering portion 8, for example, it may be a cylindrical shape, or a shape in which voids are provided regularly or irregularly on a part of the surface of the cylindrical shape. There is no particular limitation on the shape of the voids. For example, as a whole, shapes with regular voids such as a net shape, a spiral shape, a lattice shape, a polygonal shape, etc., and other shapes such as a marble pattern and a camouflage pattern can be mentioned. In the portion where the covering portion 8 is not formed, the secondary molding resin constituting the handle main body portion 7 is exposed. Further, the covering portion 8 may be configured by combining two or more of the above shapes. For example, the covering portion 8 may be cylindrical, with regular voids provided in a part thereof and irregular voids provided in other parts. Further, the end portion (base end portion 9) of the cylindrical covering portion 8 in the direction opposite to the head portion 2 direction may be open or closed. Regarding the cross-sectional shape of the covering portion 8 in the direction perpendicular to the axial direction, for example, it may be a substantially circular shape, a substantially elliptical shape, a substantially polygonal shape, and combinations thereof, etc., but there is no particular limitation.

[0017] As described above, in the covering portion 8 of the toothbrush 1 according to the present invention, various designs can be selected, and not only resins but also materials such as metals and hard and high-melting-point materials such as amorphous solids can be used. Therefore, compared with a two-color molded toothbrush in which the shape of the covering portion is generally a substantially cylindrical shape and the entire surface is covered, the possibilities of design and material types are greater, and a toothbrush with excellent design can be obtained. Further, by adjusting the length of the handle body portion 7 to be secondarily molded in the proximal end direction with respect to the primary molded product constituting the covering portion 8, there is an advantage that the center of gravity position of the toothbrush 1 can be adjusted to a position where it is easy to grip without changing the outer diameter of the covering portion 8. For example, by molding the proximal end portion 9 of the covering portion 8 so as to close, and configuring the proximal end portion 10 of the handle body portion 7 to be located on the distal end side with respect to the proximal end portion 9 of the covering portion 8, the position of the center of gravity can be adjusted to the rear end side.

[0018] Further, by providing, for example, a pattern having irregularities on the surface of the covering portion 8, a toothbrush with excellent design that is not found in conventional two-color molded toothbrushes can be obtained. The pattern on the surface of the covering portion 8 is not particularly limited, and examples thereof include patterns such as geometric patterns, twill patterns, checkered patterns, and herringbone patterns.

[0019] Further, when the covering portion 8 is made of a light-transmissive primary molding material such as a light-transmissive resin or glass, by using a colored resin as the secondary molding resin constituting the handle body portion 7, the possibilities of design are expanded, and a toothbrush with excellent design can be obtained. The light transmittance can be measured, for example, by the method described in JIS K 7375:2008 as the total light transmittance.

[0020] The head portion 2 and the handle body portion 7 constituting the toothbrush 1 of the present invention are a molded body M2 of a secondary molding resin integrally molded.

[0021] Examples of the secondary molding resin include polyester resins and polyamide resins.

[0022] For the secondary-molded resin that constitutes the head portion 2 and the handle main body portion 7, a resin having a melting point lower than that of the primary-molded material that constitutes the covering portion 8 is used. For example, when the primary-molded material is a resin with a melting point exceeding 180°C, it is preferable that the secondary-molded resin is composed of a solidified product of a secondary-molded resin melted at a molding temperature of 140 to 180°C. By using the secondary-molded resin melted within the above temperature range, there is an advantage that the melting of the resin of the primary-molded material can be efficiently suppressed during secondary molding.

[0023] As the secondary-molded resin, for example, from the viewpoint that the effects of the present invention are likely to be achieved, a polyester-based resin or a polyamide-based resin is more preferable. Examples of the polyester-based resin include polybutylene terephthalate (PBT), polyethylene terephthalate (PET), and the like. Examples of the polyamide-based resin include 6-nylon, 6,6-nylon, and the like.

[0024] In the toothbrush 1 according to the present invention, since the handle main body portion 7 is secondary-molded, unlike a conventional two-color molded toothbrush, there is no need to provide protrusions (ribs) on the surface of the primary-molded core material portion or to have gate marks. Therefore, the toothbrush according to the present invention, in which the covering portion 8 is composed of a primary-molded material such as a light-transmissive resin or glass, becomes a toothbrush with excellent design compared to a conventional toothbrush with color molding.

[0025] Also, in the toothbrush 1 according to the present invention, the thickness (base thickness) T1 of the head portion 2 may be adjusted according to the use of the toothbrush and is not particularly limited. For example, in the case of a thin head portion 2, there is a head composed of a thin implant base 5 with T1 being 4.0 mm or less, preferably 3.0 mm or less, and more preferably 2.5 mm or less.

[0026] On the ventral implanting surface where the tufts 4 of the implanting table 5 project, a plurality of bottomed implanting holes 20 having a substantially circular cross-sectional view are formed. The opening diameter, depth, number, arrangement form, etc. of the implanting holes 20 are not particularly limited, and are selected from an appropriate range according to various conditions such as the number and material of filaments per tuft.

[0027] The depth of the implanting holes 20 is appropriately determined according to the thickness T1 of the implanting table 5. The implanting holes 20 basically only need to be straight holes with a circular cross-section.

[0028] In each implanting hole 20, a tuft 4 formed by bundling a plurality of filaments and folding them in half is implanted.

[0029] Also, regarding the length of the toothbrush 1 according to the present invention, the length of the neck part and the handle part of the handle main body part 7 constituting the handle body 6, etc., may be appropriately determined according to the use of the toothbrush, and there is no particular limitation.

[0030] A method for manufacturing a toothbrush having the above-described configuration will be described below. First, a primary molded product for the covering part of the toothbrush is molded using a primary molding material having a melting point or a glass transition point of 150°C or higher. As a primary molding method, it can be appropriately selected according to the material of the primary molding material and the desired shape of the primary molded product. For example, injection molding, insert molding, blow molding, extrusion molding, metal injection (MIM) molding, casting, etc. can be mentioned. If necessary, the primary molded product made of the primary molding material may be subjected to surface processing, hole drilling, cutting, embossing, etc.

[0031] Next, the primary molded product is mounted in a secondary mold, and in a state where the secondary mold is clamped, a secondary molding resin is injected into the molding space of this secondary mold, thereby integrally secondarily molding the head part and the handle main body part constituting the handle body.

[0032] For example, a cylindrical primary molded product M1 with both ends open as shown in FIG. 3 is molded by injection molding, insert molding, blow molding, extrusion molding, metal injection (MIM) molding, or the like. Also, as shown in FIG. 7, a cylindrical primary molded product M1a with one end open and the other end closed may be used. Although not shown, the cross-sectional shape in a direction perpendicular to the axial direction of the primary molded products M1 and M1a may be substantially circular, substantially elliptical, substantially polygonal, or a combination thereof.

[0033] Next, as shown in FIG. 4, secondary molds 71 and 72 having a molding space 70 are prepared. The molding space 70 is configured to form the outer surface of the toothbrush 1, and the coating portion space 73 has a shape that fits the outer surface of the primary molded product M1. In the present invention, by mounting the surface of the primary molded product so as to fit into the secondary molds 71 and 72, the fixing strength of the primary molded product in the secondary mold is increased. Therefore, even when the secondary molding resin is injected, the position of the primary molded product does not shift. Compared with the conventional method of fixing the core member in the mold using ribs, there is less manufacturing loss and an excellent advantage in terms of cost.

[0034] The secondary molds 71 and 72 are provided with injection gates 74 for the secondary molding resin. The injection gate 74 is opened at a predetermined position facing the space for molding the head portion 2 and the handle main body portion 7 other than the coating portion space 73. If it can be opened at such a position, the volume of the molding space 70 on the base end side is larger than that of the molding space 70 on the tip end side from this position. Therefore, after the filling of the secondary molding resin into the molding space 70 on the tip end side is completed, the degree of filling into the base end side can be adjusted, and there is an advantage that it is easy to adjust the position of the base end portion 10 of the handle main body portion 7 to a desired position. The opening diameter of the injection gate 74 of the secondary mold may be appropriately selected according to the type of the secondary molding resin to a size that is easy to inject, and there is no particular limitation. In this example, the injection gate 74 opens near the neck portion between the head portion 2 and the covering portion 7 in this example, but the present invention is not limited to this.

[0035] Next, as shown in FIG. 5, the primary molded product M1 is mounted in the covering portion space 73 within the molding space 70 of the secondary molds 71 and 72, and the secondary molding resin is injected through the injection gate 74. As shown in FIG. 6, a secondary molded product M2 in which the head portion 2 and the handle main body portion 7 are integrally molded is obtained, and the toothbrush 1 in which the surface of the handle main body portion 7 is covered with the covering portion 8 is manufactured. Also, in the present invention, the center of gravity position of the toothbrush can be adjusted to an arbitrary position. For example, a primary molded product M1a with one end closed is prepared. As shown in FIG. 7, the primary molded product M1a is mounted in the covering portion space 73 within the molding space 70 of the secondary molds 71 and 72, and the secondary molding resin is injected through the injection gate 74 to obtain a secondary molded product M2a in which the head portion 2 and the handle main body portion 7 are integrally molded, and a toothbrush 1b in which the surface of the handle main body portion 7 is covered with the covering portion 8 can be manufactured. The center of gravity position of the obtained toothbrush 1b is adjusted to be on the rear end side rather than the center of gravity position of the toothbrush 1 shown in FIG. 2.

[0036] In this way, toothbrushes 1 and 1b including the head portion 2 and the handle body 6 connected to the head portion 2 can be molded.

[0037] The tufts 4 may be implanted in the implanting holes 20 of the implanting base 5 provided on the head portion 2 by a known method.

[0038] Although the embodiments of the present invention have been described above, the present invention is not limited to such examples, and it goes without saying that the present invention can be implemented in various forms without departing from the gist of the present invention.

Example

[0039] (Example 1: Manufacture of Toothbrush 1a) The following shows the conditions of a preferred example (toothbrush 1a) of a primary molding material that constitutes the covering portion 8 made of metal and a secondary molding resin that integrally constitutes the head portion 2 and the handle main body portion 7 when manufacturing the toothbrush 1a having a thin head shown in FIGS. 1 and 2.

[0040] Toothbrush 1a: Primary molding material: Stainless steel (melting point of about 1400 ° C), secondary molding resin: PBT (melting point of 225 ° C)

[0041] The toothbrush 1a was manufactured by the following procedure. First, by MIM molding the primary molding material, as shown in FIG. 3, a cylindrical primary molded product M1 for the covering portion of the toothbrush was molded. Next, as shown in FIG. 5, the primary molded product M1 was mounted in the covering portion space 73 within the molding space 70 of the secondary molds 71 and 72, and the secondary molds 71 and 72 were clamped. Next, molten secondary molding resin was injected into the molding space 70 of the secondary molds 71 and 72 from the injection gate 74, and as shown in FIG. 6, the head portion 2 and the handle main body portion 7 that constitutes the handle body 6 were integrally secondary molded. After molding the molded product M2, tufts 4 were implanted in each implanting hole 20 of the implanting table 5 to manufacture the toothbrush 1a shown in FIG. 2. Note that the proximal end portion 10 of the handle main body portion 7 protruded to the proximal end side from the opening of the proximal end portion 9 of the covering portion 8 and was molded to form the rear end portion of the toothbrush 1a.

[0042] (Example 2: Manufacturing of Toothbrush 1b with Changed Center of Gravity Position) As shown in FIG. 7, except that a primary molded product M1a with an open distal end side and a closed proximal end portion 9 was used, the same primary molding material and secondary molding resin as those of the toothbrush 1a were used, and the proximal end portion 10 of the handle main body portion 7 was After molding the secondary molded product M2a in which the handle main body portion 7 that constitutes the head portion 2 and the handle body 6 was integrally secondary molded so as to be on the distal end side of the proximal end portion 9 of the covering portion 8, tufts 4 were implanted in each implanting hole 20 of the implanting table 5 to manufacture the toothbrush 1b shown in FIG. 8. The obtained toothbrush 1b had a handle body 6 with the same outer diameter as that of the toothbrush 1a, but the center of gravity position thereof was adjusted to be on the rear end side rather than the center of gravity position of the toothbrush 1a.

Explanation of Signs

[0043] 1 1a 1b Toothbrush 2 Head part 4 Bristle bundle 5 Bristle mounting base 6 Handle body 7 Handle main body part 8 Cover part 9 Base end part of the cover part 8 10 Base end part of the handle main body part 7 20 Bristle implanting hole 70 Molding space 71 Second mold 72 Second mold 73 Space for the cover part 74 Injection gate M1 M1a Primary molded product M2 M2a Secondary molded product

Claims

1. A toothbrush comprising a head portion in which tufts of bristles are implanted and a handle body connected to the head portion, wherein the handle body is composed of a handle main body portion integrally formed with the head portion and a covering portion covering a part or all of the surface of the handle main body portion, the covering portion is a molded body of a primary molding material having either a melting point or a glass transition point of 150°C or higher, and the head portion and the handle main body portion are molded bodies of a secondary molding resin. A toothbrush characterized by this.

2. The toothbrush according to claim 1, wherein the primary molding material is polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene copolymer (AS resin), polystyrene (PS), polyethylene (PE), polypropylene (PP), metal, or an amorphous solid.

3. The toothbrush according to claim 1 or 2, wherein the secondary molding resin is a polyester-based resin or a polyamide-based resin.

4. A method for manufacturing a toothbrush comprising a head portion in which tufts of bristles are implanted and a handle body connected to the head portion, after molding a primary molded product for the covering portion constituting the handle body using a primary molding material having either a melting point or a glass transition point of 150°C or higher, characterized in that the primary molded product is mounted in a secondary mold, and the secondary molding resin is injected into the molding space of the secondary mold to integrally secondarily mold the head portion and the handle main body portion constituting the handle body. A method for manufacturing a toothbrush.

5. The method for manufacturing a toothbrush according to claim 4, wherein the primary molding is selected from the group consisting of injection molding, insert molding, blow molding, extrusion molding, metal injection molding, and casting.

6. The method for manufacturing a toothbrush according to claim 4 or 5, wherein the primary molding material is polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene copolymer (AS resin), polystyrene (PS), polyethylene (PE), polypropylene (PP), metal, or an amorphous solid.

7. The method for manufacturing a toothbrush according to claim 4 or 5, wherein the secondary molding resin is a polyester-based resin or a polyamide-based resin.

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