JP4862242B2 - Toothbrush manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a toothbrush, and more particularly to a toothbrush in which a bundle of hairs obtained by focusing a large number of filament bristles is implanted in a state in which a molten lump formed at an end of the bundle is embedded in the planted part.
[0002]
[Prior art]
In a general toothbrush, a bunch of bundles of a large number of filament bristles is folded back, and the folded end is pushed and fixed by a staple into a flocked hole formed in the flocked portion of the toothbrush. On the other hand, as a method for manufacturing a toothbrush that does not use staples, flocking is performed by filling a mold cavity with a molding material having a hair bundle holding hole that holds the folded end of the hair bundle protruding into the cavity. There is also a method in which the ends of the hair bundles are embedded in the molding material at the time of molding the part. However, in the toothbrush manufactured by this method, when the molding material is filled into the mold cavity, the molding material leaks into the gap between the hair bundle and the hair bundle holding hole of the mold and the gap between the filament bristles of the hair bundle ( Flash failure) occurs. Therefore, in order to prevent the leakage of the molding material, as disclosed in, for example, Japanese Patent Publication No. 6-16725, Japanese Patent No. 2601452, Japanese Patent No. 2732875, etc., it protrudes into the mold cavity during molding. A molten mass larger than the diameter of the hair bundle holding hole of the mold is formed at the protruding end portion of the bundle, and the molding material is put into the cavity in a state where the molten mass is in close contact with the hair bundle holding hole of the mold. A method for preventing leakage of the molding material by filling is proposed.
[0003]
When the molten lump formed at the protruding end of the hair bundle into the cavity as described above is brought into close contact with the mold hair bundle holding hole, the mold hair bundle holding hole is melted when filling the mold with the molding material. It is closed by the lump and leakage of the molding material from the hair bundle holding hole can be prevented. However, in this case, in the toothbrush after molding, since the molten mass is located on the surface of the flocked portion and the depth of the flocking of the flocked portion is shallow, the uprightness of the follicle can be maintained. Have difficulty. Therefore, in order to maintain the uprightness of the hair bundle, if the depth of implantation of the molten lump at the end of the hair bundle into the cavity is increased, the molten lump formed at the end of the hair bundle and the hair bundle holding of the mold are held. There is a problem that a gap is inevitably formed between the hole and the molding material leaks from the gap when the molding material is filled into the cavity. In addition, there is a problem that the depth of implantation of the molten mass at the end of the hair bundle becomes shallow because the hair bundle and the molten mass are pushed out of the cavity by the filling (injection) pressure of the molding material into the cavity. Therefore, it is also considered to reduce the filling pressure of the molding material into the cavity in order to prevent the molding material from leaking and the injection depth of the molding material from decreasing the depth of implantation of the molten lump at the end of the hair bundle. However, in most toothbrushes, the flocked part and the handle part are simultaneously integrally formed in a continuous cavity of the same mold, so when the filling pressure is lowered, the shape of the handle part is complicated, For example, there may be a problem of poor filling of the molding material into the logo mark portion.
[0004]
[Problems to be solved by the invention]
In view of the problems related to the method of manufacturing a toothbrush as described above, the bristle end is projected into the cavity from the bristle bundle holding hole provided in the mold, and a molten mass is formed at the projecting end. In a method for manufacturing a toothbrush in which a flocking part is formed by filling a molding material into a cavity, a mold cavity is maintained while ensuring the planting depth of the molten lump at the end of the bristles and maintaining the uprightness of the bristles. It is an object of the present invention to provide a method of manufacturing a toothbrush that can prevent the leakage of the molding material from the bristles holding hole of the mold when the molding material is filled into the mold.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, as a result of repeated studies, the present inventors have previously formed a flocked portion cover that constitutes the surface of the flocked portion of the toothbrush, and provided the hair bundle holding hole on the cavity side. With the flocked portion cover attached to the inner surface, the hair bundle end is protruded into the cavity, the molding material is filled into the cavity, and the flocked portion is molded integrally with the flocked portion cover, to the flocked portion. Maintaining the uprightness of the hair bundle by ensuring the depth of implantation of the molten mass at the end of the hair bundle and preventing the molding material filled in the cavity from leaking from the hair bundle holding hole provided in the mold It came to complete the manufacturing method of the toothbrush which becomes.
[0006]
That is, in the method of manufacturing a toothbrush according to the present invention, a flock hole that matches the hair bundle holding hole is formed on the cavity side inner surface of the first mold member provided with the hair bundle holding hole that holds the hair bundle that has focused the filament bristles. Installed and pre-formed flocked part cover is attached, and the hair bundle is inserted into the flock hole of the flocked part cover and the flock holding hole of the first mold member, and the end part is held in a state of protruding toward the cavity. Then, after the protruding end portion is melted to form a molten lump, a molding material is filled into a cavity formed by aligning the second mold member with the first mold member and integrated with the flocked portion cover. A flocked part is formed.
[0007]
According to the manufacturing method of the toothbrush of the present invention as described above, the flocked portion cover is mounted on the cavity side inner surface of the first mold member provided with the bristle bundle holding hole when the molding material is filled into the cavity. Thus, the uprightness of the hair bundle is maintained by ensuring that the molten lump at the end of the hair bundle has a planting depth at least equal to the thickness of the flocked portion cover.
[0008]
In the above method, the molten mass at the protruding end of the hair bundle on the cavity side is formed larger than the diameter of the flock hole of the flocked portion cover, and the molten mass is brought into close contact with the opening edge of the flocked hole of the flocked portion cover. It is preferable to fill the molding material in a heated state. In this case, the flocking hole is closed by bringing the molten mass at the end of the bristles into close contact with the opening edge of the flocking hole of the flocking part cover, and the molding material from the flocking hole to the bristles holding hole of the first mold member Can be prevented, and the planting depth of the molten mass at the ends of the hair bundle can be made constant and uniform.
[0009]
Further, in the above method, the undercut portion is formed between the flocked portion cover and the flocked portion formed by filling the cavity with the molding material, thereby fixing the flocked portion cover and the flocked portion. Strength can be improved.
[0010]
Furthermore, while forming a cylindrical convex part around the opening part of the hair | bristle bundle holding hole in the cavity side inner surface of a 1st type | mold member, the annular recessed part closely_contact | adhered to the said cylindrical convex part is provided around the flock hole of the flock part cover When the flocked portion cover is mounted on the cavity side inner surface of the first mold member in a state where the annular concave portion is unevenly fitted to the cylindrical convex portion, the hair bundle holding hole opens inside the flocked portion cover. Therefore, even if the molding material leaks into the hair bundle holding hole, it is not immediately exposed to the surface of the flocked portion cover, and the cylindrical convex portion and the annular concave portion are concavo-convexly fitted, Positioning at the time of attaching the flocked part cover to the inner surface of one mold becomes easy and can be reliably attached.
[0011]
In addition, in order to form a molten lump at the protruding end portion of the hair bundle protruding into the cavity, a melt source is formed by bringing a heat source into contact with the protruding end portion of the hair bundle on the cavity side, thereby reducing the thickness of the molten lump. Therefore, the thickness of the flocked portion can be reduced.
[0012]
In order to increase the fixing strength between the flocked portion cover and the flocked portion molding material, the flocked portion cover is preferably molded from mutually compatible synthetic resins, and homogeneous materials are particularly preferable. Further, when a flocked portion cover is molded from a thermoplastic elastomer, the flocked portion is more likely to bend as the thickness of the flocked portion molded from a relatively hard material is reduced.
[0013]
The toothbrush of the present invention is manufactured by the method as described above, Pre-molded separately from the hair bundle The flocked part cover is , A hair bundle that is integrally fixed to the surface of the flocked portion and that has a large number of filament bristles is formed by the flocked portion cover. Formed in It is characterized in that it is planted in such a manner that the end of the planted hole is embedded in the planted part, and a molten mass is formed at the embedded end.
[0014]
According to the toothbrush of the present invention as described above, since the hair bundle is fixed to the flocked portion by the molten mass of the embedded end portion in the flocked portion without using staples, the flocking can be performed simultaneously with the molding. And the thickness of the flocked portion can be reduced. Further, when the flocked portion and the flocked portion cover are formed of different materials, for example, synthetic resins having different colors, a toothbrush having excellent design properties is obtained.
[0015]
Further, in the case where a melted mass larger than the hole diameter of the flock hole of the cover is formed at the embedded end portion of the hair bundle, and the molten mass is in close contact with the opening edge of the flock hole of the flocked portion cover, The planting depth of the molten mass is maintained constant.
[0016]
Furthermore, in the case where the undercut portion is formed between the flocked portion cover and the flocked portion, the fixing strength between the flocked portion cover and the flocked portion is large, and peeling of the flocked portion cover from the flocked portion is prevented.
[0017]
Toothbrush handles and flocked parts are molded from a relatively hard synthetic resin material such as polypropylene, but by molding the flocked part cover with a soft thermoplastic elastomer, the thickness of the hard material part in the flocked part The thickness can be reduced and it becomes easier to bend. Furthermore, it can be set as a toothbrush with higher design property by providing a decoration part, a slip stopper, etc. with the said thermoplastic elastomer in a handle | steering-wheel part. In addition, by applying antibacterial treatment to the flocked part cover, which is a separate member, the antibacterial effect of the flocked part is more effective than when antibacterial treatment is applied to the handle part of the toothbrush and the whole flocked part that are usually integrally molded. Can be improved.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to the drawings. 1-6 is explanatory drawing which shows an example of the process of manufacturing a toothbrush by the method of this invention. In FIG. 1, what is shown by the code | symbol 1 is the 1st type | mold member which is one type | mold member of the injection mold which consists of a pair of type | mold member which forms a cavity in order to shape | mold a toothbrush. On the cavity side inner surface 4 of the first mold member 1, there is formed a recess 5 for mounting a flocking portion cover, which will be described later, and a handle formed continuously with the flocking portion of the toothbrush continuously from the recess 5. The molding recessed part 6 of the part is formed. Further, the hair-planting-portion-mounting concave portion 5 is provided with a plurality of hair bundle holding holes 2 corresponding to the planting positions of a plurality of hair bundles in which a large number of filament hairs are focused, which are planted in the hairbrushing portion of the toothbrush. In addition, a cylindrical convex portion 3 is formed around the cavity side opening of each hair bundle holding hole 2.
[0019]
Next, in FIG. 1, what is shown by the code | symbol 7 is the flocking part cover integrally fixed to the surface of the flocking part of a toothbrush, and is shape | molded by injection molding etc. previously from molding materials, such as a synthetic resin or a thermoplastic elastomer. The A plurality of flocking holes 8 that coincide with the hair bundle holding holes 2 provided in the first mold 1 are formed in the flocking portion cover 7, and the first flocking holes 8 are arranged on the first mold 1 side. At the opening edge of the surface 9, a tapered annular recess 10 is formed in close contact with the cylindrical protrusion 3 formed around the hair bundle holding hole 2 of the first mold member 1. And the flock hole 8 of this flocking part cover 7 and the hair bundle holding hole 2 of the said 1st type | mold member 1 are made to correspond, The cyclic | annular recessed part 10 surrounding the flock hole 8 and the cylindrical convex part 3 around the hair bundle holding hole 2 Are inserted into the concave portion 5 for attaching the flocked portion cover of the first mold member 1 so that the flocked portion cover 7 is mounted in close contact, and the cutting plate 11 is mounted on the cavity side of the flocked portion cover 7. And fix. The cutting plate 11 has a plurality of hair bundle insertion holes 12 that coincide with the hair bundle holding holes 2 of the first mold member 1 and the flock holes 8 of the flocked portion cover 7.
[0020]
As described above, after the pre-molded hair cover 7 and the cutting plate 11 are mounted and fixed on the cavity-side surface 4 of the first mold member 1, a plurality of filament hairs f are formed as shown in FIG. After the hair bundle F is supplied and inserted through the hair bundle insertion hole 12 of the cutting plate 11, the hair implantation hole 8 of the hair transplant part cover 7 and the hair bundle holding hole 2 of the first mold member 1, each filament f of the hair bundle F is applied to each filament f. On the other hand, rounding and profile processing are performed as necessary, and each hair bundle F is cut by the cutter 14 along the cavity-side surface 13 of the cutting plate 11 as shown in FIG. Align the protruding length of the hair bundle F.
[0021]
Then, the cutting plate 11 is removed, and the molten mass 15 is formed at the cavity side protruding end of each hair bundle F as shown in FIG. This molten lump 15 is in a state where the mold is opened, and the filament f is thermally melted by contact or non-contact with a heat source heated to a temperature at which the filament of the hair bundle F can be melted, or in a state where the mold is closed. There is a method of introducing air or an inert gas heated to a temperature at which the filament f can be melted. The molten mass 15 is preferably formed larger than the diameter of the flocked hole 8 of the flocked portion cover 7. When the filament f is melted without contact with the heat source or when the filament f is melted with heated air or an inert gas, the melted filament f becomes a ball, and the thickness of the molten mass 15 is difficult to adjust. . On the other hand, in the case of the method of forming the molten mass 15 by bringing the filament f into contact with a heat source and thermally melting it, the thickness can be reduced by pressing the heat source against the molten mass. The thickness can be easily adjusted, and therefore the thickness of the entire flocked portion of the toothbrush can be reduced.
[0022]
After the molten mass 15 is formed at the cavity side protruding end of the hair bundle F as described above, the second mold member 16 is aligned with the first mold member 1 of the injection mold as shown in FIG. A cavity C for integrally molding the flocked portion and the handle portion of the toothbrush is formed, and the fused synthetic resin material 17 as a molding material is injected and filled into the cavity C, so that the flocked portion 18 and the handle portion of the toothbrush are filled. At the same time, the end of the hair bundle F in which the molten mass 15 is formed is embedded in the molding material of the flocked portion 18, and the flocked portion cover 7 is integrally fixed to the molding material of the flocked portion 18.
[0023]
After the flocking portion 18 and the handle portion 19 are simultaneously integrally molded as described above, the first mold member 1 and the second mold member 16 of the injection mold are opened as shown in FIG. The toothbrush 20 formed by pulling out the hair bundle F from the hair bundle holding hole 2 is taken out.
[0024]
According to the method for manufacturing a toothbrush as described above, when the molding material 17 is filled into the cavity C, the flocked portion cover 7 is attached to the cavity side inner surface 4 of the first mold member 1 provided with the bristle bundle holding hole 2. Therefore, the molten mass 15 at the end of the hair bundle F of the hair bundle F planted in the hair planting portion 18 has a planting depth d that is at least equal to or greater than the thickness t of the hair planting cover 7. The uprightness of the bundle F is maintained. Moreover, since the hair | bristle bundle is being fixed to the flocked part by the molten lump 15 embed | buried in the flocked part 18 without using a staple, the thickness T of the flocked part 18 can be made thin. Further, as in the above embodiment, the cylindrical convex portion 3 is formed around the hair bundle holding hole 2 opened on the cavity side inner surface 4 of the first mold member 1, and is attached to the inner surface 4 of the first mold member 1. In the case where an annular recess 10 that is in close contact with the cylindrical projection 3 is provided around the flocking hole 8 of the flocking part cover 7, the molding material 17 is temporarily placed through the flocking hole 8 of the flocking part cover 7. Even if it leaks into the hair bundle holding hole 2 of the mold member 1, since the hair bundle holding hole 2 is open inside the flocked portion cover 7, the leaked molding material 17 immediately has the surface 9 of the flocked portion cover 7. There is no exposure. Further, by fitting the cylindrical convex portion 3 provided on the first mold member 1 and the annular concave portion 10 provided on the flocked portion cover 7 into a concave and convex shape, the flocked portion on the cavity side inner surface 4 of the first mold 1 is provided. Positioning when the cover 7 is attached is easy and can be reliably attached.
[0025]
FIG.7 and FIG.8 shows other embodiment of the manufacturing method of the toothbrush of this invention. In this embodiment, after forming the molten mass 15 larger than the hole diameter of the flock hole 8 provided in the flocked portion cover 7 on the protruding end portion protruding to the cavity side of the hair bundle F in the previous embodiment (FIG. 4) As shown in FIG. 7, the end of the hair bundle F provided with the molten mass 15 is pushed toward the first mold member 1 side, or the hair bundle F protruding from the outer surface side of the first mold member 1 is moved. By pulling, the molten mass 15 is pressed against the flocked portion cover 7 to bring the molten mass 15 into close contact with the opening edge of the flocked hole 8, and then the second mold member 16 is attached to the first mold member 1 as shown in FIG. A cavity C for integrally molding the toothbrush flocking part 18 and the handle part 19 is formed, and the synthetic resin material 17 is injected and filled in the same manner as described above, whereby the toothbrush flocking part 18 and the handle part are formed. At the same time as molding 19, the flocked part 18 The end forming the molten mass 15 of tufts F in the molding material embedded, and the flocked cover 7 to the bristle portion 18 is for fixing together. In the above example, after the molten lump 15 is formed at the protruding end protruding from the cavity side of the hair bundle F, the end of the hair bundle F provided with the molten lump 15 is directed to the first mold member 1 side. Although the case where the molten lump 15 is pressed against the flocked portion cover 7 by pushing or pulling the hair bundle F protruding from the outer surface side of the first mold member 1 is described, the molten lump 15 is brought into close contact with the opening edge of the flocked hole 8. When the molten lump 15 is formed, the end of the hair bundle F is melted to the vicinity of the surface of the flocked portion cover 7, and the formed molten lump 15 is pressed against the flocked portion cover 7 so as to be in close contact with the opening edge of the flocked hole 8. Also good.
[0026]
In this embodiment, the flock hole 8 of the flocked portion cover 7 is closed by the molten mass 15 formed at the cavity-side protruding end portion of the follicle bundle F, and the flock holding hole 2 of the first mold member 1 from the flock hole 8. The molding material 17 can be prevented from leaking to the surface, and the planting depth d of the molten mass 15 at the end of the hair bundle F from the surface 9 of the hair-planting portion cover 7 can be made constant.
[0027]
9 and 10 show still another embodiment. In this embodiment, for example, as shown in FIG. 10, the flocked portion cover 7 is made smaller than the outline of the flocked portion 18 of the toothbrush, and as shown in FIG. 9, the cavity C side inner surface 4 of the first mold member 1 is formed. An undercut portion 22 is provided between the flocked portion cover 7 to be attached and the toothbrush flocked portion 18 formed by filling the molding material 17 into the cavity C, for example, around the flocked portion cover 7 as shown in the figure. Yes. Thus, by providing the undercut portion 22 between the flocked portion cover 7 and the flocked portion 18 formed integrally therewith, the fixing strength between the two increases, so that the flocked portion cover 7 becomes the flocked portion. Peeling from 18 can be prevented. In addition, in FIG. 10, although the flock hole of the hair | bristle bundle F has shown the circular thing, it is not limited to this, The shape of the flock hole can be made into squares and other arbitrary shapes.
[0028]
Further, the fixing strength between the flocked portion cover 7 and the flocked portion 18 is also largely due to the characteristics of the molding materials of both. That is, a high fixing strength can be obtained by molding the flocked portion cover 7 and the flocked portion 18 with synthetic resin materials that are compatible with each other. As a combination of the compatible molding materials, for example, the flocked portion cover 7 and the flocked portion 18 are both molded from polypropylene, the flocked portion cover 7 is molded from an olefin elastomer, and the flocked portion 18 is molded from polypropylene. . Further, in the case of a thermoplastic elastomer, the adhesiveness to relatively hard synthetic resin materials such as polypropylene and copolyester resin which are generally used as a molding material for toothbrushes is relatively excellent. Therefore, it is a preferred embodiment that the flocked portion cover 7 is molded with this thermoplastic elastomer and is integrally fixed in a mold when the flocked portion is molded with a synthetic resin material such as polypropylene or copolyester resin. is there. In addition, since the surface of the flocked portion is composed of a relatively soft thermoplastic elastomer, the thickness of the hard portion in the flocked portion is reduced, and the flocked portion is easily deformed accordingly. The brushing pressure can be controlled by the bending of the part. Moreover, also when using the flocked part cover 7 which consists of resin and thermoplastic elastomers compatible with the flocked part 18 as mentioned above, the undercut part 22 is formed between the flocked part cover 7 and the flocked part 18. Needless to say, this is effective in increasing the adhesion strength between the two.
[0029]
The toothbrush of the present invention manufactured by the above method is shown in FIG. 11 because the preliminarily molded flocked portion cover 7 is integrally fixed to the flocked portion 18 when the flocked portion 18 is molded. Thus, it becomes a toothbrush excellent in the designability by shape | molding the flocked part 18 and the flocked part cover 7 in the toothbrush 10 with another material, for example, a synthetic resin with a different color. Furthermore, by providing the handle portion 19 and the like with the same molding material as the flocked portion cover 7 such as a thermoplastic elastomer, the toothbrush with higher design can be obtained.
[0030]
【Effect of the invention】
According to the present invention, the hair bundle end is projected into the cavity from the hair bundle holding hole provided in the mold, and the molding material is filled in the cavity with the molten lump formed on the projected end. In the manufacturing method of the toothbrush formed by molding the bristle bundle end where the flocked portion cover is attached to the cavity side inner surface of the mold member provided with the bristle bundle holding hole to form a molten lump, and protruding into the cavity Since the molding material is filled into the cavity, the molten lump at the end of the hair bundle is secured with at least a planting depth corresponding to the thickness of the hair transplant cover, so that the uprightness of the hair bundle is maintained. .
[0031]
Molding material into the cavity in a state in which the molten lump at the protruding end portion on the cavity side of the hair bundle is formed larger than the hole diameter of the flock hole of the cover and the molten lump is in close contact with the opening edge of the flock hole of the flocked portion cover Is filled, the flock hole of the flocked portion cover is closed by the molten mass, and leakage of the molding material from the flocked hole to the hair bundle holding hole of the mold member can be prevented. In addition, the depth of the molten lump at the end of the hair bundle can be made constant and uniform by the thickness of the flocked portion cover.
[0032]
If an undercut part is formed between the flocked part cover and the flocked part molded by filling the molding material into the cavity, the fixing strength between the flocked part cover and the flocked part is improved, and the flocked part cover Can be prevented.
[0033]
By forming a cylindrical convex portion around the hair bundle holding hole on the inner surface of the mold member and providing an annular concave portion in close contact with the cylindrical convex portion around the flock hole of the flocked portion cover, the hair of the mold member Since the bundle holding hole opens inside the hair transplantation part cover, even if the molding material leaks into the hair bundle holding hole, it is not immediately exposed to the surface of the hair transplantation part cover. Further, when the flocked portion cover is attached to the inner surface of the mold, positioning can be facilitated and reliably attached by the concave and convex fitting between the cylindrical convex portion and the annular concave portion.
[0034]
When a heat source is brought into contact with the protruding end portion of the bristle bundle protruding into the cavity to form a molten mass, the thickness of the molten mass can be reduced by pressing the heat source against the molten mass, and therefore the flocked portion of the toothbrush The thickness of can also be reduced.
[0035]
The flocked part cover and the flocked part are molded from mutually compatible synthetic resins, or the flocked part cover is formed from a thermoplastic elastomer, so that the flocked part cover has a high fixing strength to the flocked part. As a result, peeling of the flocked portion cover can be prevented.
[0036]
In the toothbrush of the present invention, since the hair bundle is fixed to the flocked portion by a molten mass embedded in the flocked portion without using staples, the thickness of the flocked portion can be reduced. Further, when the flocked portion and the cover are formed of different materials, for example, synthetic resins having different colors, a toothbrush excellent in design is obtained. Furthermore, since the flocked portion cover which is a separate member is fixed to the surface of the flocked portion, antibacterial properties can be efficiently imparted to the flocked portion of the toothbrush by applying antibacterial treatment to the flocked portion cover. it can.
[0037]
In the case where the melted lump at the embedded end portion of the hair bundle is formed larger than the hole diameter of the flock hole of the cover, and this is in close contact with the opening edge of the flock hole of the cover, the planting depth of the hair bundle is constant. Maintained.
[0038]
In the case where an undercut is formed between the cover and the flocked portion, the cover and the flocked portion have a high fixing strength, and the cover is prevented from peeling off from the flocked portion.
[0039]
When the cover is made of a thermoplastic elastomer, the flocked portion formed from a relatively hard material is made thinner by the amount of the cover, so that the flocked portion is easily bent and the usability of the toothbrush is improved. Furthermore, it can be set as a toothbrush with higher design property by providing a decoration part, a slip stopper, etc. with the said thermoplastic elastomer in a handle | steering-wheel part.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a process for producing a toothbrush according to the method of the present invention, and is a cross-sectional view showing a state where a flocking part cover and a cutting plate are mounted on a mold member of an injection mold.
FIG. 2 is an explanatory view of a process of manufacturing a toothbrush by the method of the present invention, and is a cross-sectional view showing a state in which a bunch of bundles of many filament bristles is fed to a mold member of a mold.
FIG. 3 is an explanatory view of a process for producing a toothbrush by the method of the present invention, and is a cross-sectional view showing a state in which a hair bundle supplied to a mold member of a mold is cut to a predetermined length.
FIG. 4 is an explanatory view of a process for producing a toothbrush by the method of the present invention, and is a cross-sectional view showing a state in which a molten lump is formed at an end portion of a hair bundle supplied to a mold member of a mold.
FIG. 5 is an explanatory view of a process for manufacturing a toothbrush by the method of the present invention, and is a cross-sectional view showing a state in which a toothbrush is molded by closing a mold and filling a molding material.
FIG. 6 is an explanatory view of a process for producing a toothbrush by the method of the present invention, and is a cross-sectional view showing a state in which a molded toothbrush is taken out from a mold.
FIG. 7 is a cross-sectional view showing a state in which the molten mass at the end of the hair bundle supplied to the mold member of the mold is brought into close contact with the flocked portion cover in another embodiment.
FIG. 8 is a cross-sectional view showing how a toothbrush is molded by closing a mold and filling a molding material in the embodiment.
FIG. 9 is a cross-sectional view showing how a toothbrush is molded by closing a mold and filling a molding material in an embodiment in which an undercut portion is formed between a flocked portion cover and a flocked portion.
FIG. 10 is a plan view of a flocked portion of the toothbrush in the embodiment.
FIG. 11 is a perspective view showing an embodiment of a toothbrush according to the present invention.
[Explanation of symbols]
1: 1st type | mold member, 2: Hair bundle holding | maintenance hole, 3: Cylindrical convex part, 4: The cavity side surface in a 1st type | mold member, 5: Recessed part for flocking part cover mounting, 6: Concave part for handle part shaping | molding : Planted part cover, 8: planted hole, 9: mold member side surface in planted part cover, 10: annular recess, 11: cutting plate, 12: hair bundle insertion hole, 13: cutting plate surface, 14: cutter, 15: Melt lump, 16: second mold member, 17: molding material, 18: flocked part, 19: handle part, 20: toothbrush, 21: anti-slip, 22: undercut part, f: filament bristles, F: hair bundle.

Claims (11)

On the cavity side inner surface of the first mold member provided with a hair bundle holding hole for holding a hair bundle that has bundled filament hairs, a flocked portion cover that is pre-shaped with a flock hole that matches the hair bundle holding hole is attached, The bristles are inserted through the flock holes of the flocking portion cover and the bristles holding holes of the first mold member, and the ends are protruded toward the cavity, and the protruding ends are melted to obtain a molten mass. And forming a flocked portion integrally with the flocked portion cover by filling a molding material into a cavity formed by aligning the second mold member with the first mold member. Production method. Fill the molding material with the molten mass at the protruding end of the hair bundle on the cavity side larger than the diameter of the flock hole of the flocked portion cover, and with the molten mass in close contact with the opening edge of the flocked hole of the flocked portion cover The manufacturing method of the toothbrush of Claim 1 formed. The manufacturing method of the toothbrush of Claim 1 or 2 which forms an undercut part between the flocked part cover and the flocked part shape | molded by filling of the molding material in a cavity. Forming a cylindrical convex portion around the opening portion of the hair bundle holding hole on the cavity side inner surface of the first mold member, and providing an annular concave portion in close contact with the cylindrical convex portion around the flock hole of the flocking portion cover; The method for manufacturing a toothbrush according to any one of claims 1 to 3, wherein a flocked portion cover is attached to the cavity side inner surface of the first mold member in a state where the annular concave portion is unevenly fitted to the cylindrical convex portion. The manufacturing method of the toothbrush in any one of Claims 1-4 formed by making a heat source contact the cavity side protrusion edge part of a bristle bundle, and forming a molten lump. The method for producing a toothbrush according to any one of claims 1 to 5, wherein a molding material for the flocked part cover and the flocked part is molded from mutually compatible synthetic resins. The method for producing a toothbrush according to any one of claims 1 to 5, wherein the flocked portion cover is formed from a thermoplastic elastomer. A flocked part cover that is pre-molded separately from the hair bundle is fixed integrally to the surface of the flocked part, and the hair bundle that focuses a large number of filament hairs penetrates the flocked hole formed in the flocked part cover. And the toothbrush characterized by being planted in the state by which the edge part was embed | buried in the flocked part, and the molten lump is formed in this buried edge part. The toothbrush according to claim 8, wherein a melted mass larger than a diameter of the flock hole of the flocked portion cover is formed at an embedded end portion of the bristles, and the molten mass is in close contact with an opening edge of the flocked hole of the flocked portion cover. The toothbrush according to claim 8 or 9, wherein an undercut portion is formed between the flocked portion cover and the flocked portion. The toothbrush according to any one of claims 8 to 10, wherein the flocked portion cover is made of a thermoplastic elastomer.

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