JP2012115445A - Toothbrush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toothbrush in which deformation rigidity and strength of a bristle embedded base can be improved while excellent operability is maintained with the brush having a bristle embedded portion formed by molding a back molded portion on the back side of the bristle embedded base.SOLUTION: The bristle embedded portion 17 includes: a bristle embedded base 12; a bristle tuft 14 having a molten lump 15 by one end part 14a heated and melted; and a back molded portion 16 that is molded by covering the back side of the bristle embedded base 12. The peripheral wall 19 of the bristle embedded base 12 has, in the tip end part of the bristle embedded portion 17, a curved peripheral part 21 projectingly curved toward the tip end direction. The transplantation holes 13 have a tapered opening peripheral part 13a in which a cross sectional area is taperingly expanded on the bottom face 20a of a transplantation recess 20. The peripheral wall 19 at the tip end with the curved peripheral part 21 includes a thick part 22 having the largest thickness inward in a part between the outer edges of the tapered opening peripheral part 13a', 13a' of the pair of tip end transplantation holes 13', 13' near the peripheral wall 19.

Description

  The present invention relates to a toothbrush, and more particularly, to a toothbrush having a handle portion and a flocked portion that is connected to the tip end side of the handle portion and has a plurality of hair bundles formed by bundling bristles.

  As a method for manufacturing a toothbrush, a flat wire flocking method is generally known in which a flat wire is driven into the middle part of the bristles and is then planted. A certain strength is required for the flocking table for flocking the hair bundle. Therefore, it is necessary to increase the thickness of the flocking table or to increase the distance between the outer peripheral edge of the flocking table and the flocking hole.

  On the other hand, a flocking method that does not use a flat wire, such as an in-mold molding method, is known. For example, as described in Patent Document 1, a hair bundle is fixed to a mold for forming a toothbrush, one end of the fixed hair bundle is melted to form a melted portion, and the melted portion is disposed inside Filling the mold with resin and molding the handle part and the head part of the toothbrush integrally, or as described in Patent Document 2, melt one end part of the hair bundle into the head cassette and plant it. A method is known in which, after being installed, the head cassette is fitted into a recess provided in the head portion and fixed.

  As described in Patent Documents 3 and 4, a hair bundle formed by bundling a plurality of bristles is inserted into a plurality of flock holes of a previously formed flock base, and the back side of the flock base of the hair bundle inserted into the flock hole The back molding part is integrated with the flocked base by heating one end part that protrudes to form a molten lump, covering the formed molten lump and filling and curing the coating resin on the back side of the flocked base There is known a method for forming a flocked portion (head portion) of a toothbrush by molding a toothbrush.

  The toothbrushes formed by the manufacturing methods described in Patent Documents 3 and 4 have a plurality of flocking portions provided on the bottom surface of the flocking concave portion on the inner side of the peripheral wall standing on the back side. A flocking base having a flocking hole formed therein, a hair bundle having a molten lump formed by heating and melting at one end portion on the bottom surface of the flocking recess, an upper end surface of the peripheral wall of the flocking base, and flocking And a back molding part formed so as to cover the concave part for use.

JP 2001-258642 A JP 2008-161271 A JP 2003-135154 A JP 2003-310353 A

  In the molding method such as the in-mold method, the thickness of the flocked portion can be made thinner than the flat flocking method, the hair bundle can be flocked as close as possible to the periphery of the flocked portion, or the hair bundle can be oblique to the flocked portion. For example, there is an advantage that the planted part is made compact and the degree of freedom of the planted form is increased.

  However, in the molding method of the in-mold method described in Patent Document 1, since the region other than the melted portion of the hair bundle is disposed inside the mold, the pressure of the resin filled in the mold is sufficiently increased. There is a problem that the resin filled between the hair bundles tends to leak out. In the method of fitting the head cassette described in Patent Document 2, the width of the outer peripheral wall for fitting the head cassette into the head portion and the hair bundle at the edge of the head cassette portion are arranged on the periphery of the head portion. The width for planting is required, and the distance from the periphery of the head part of the toothbrush to the flock hole is increased. According to the methods described in Patent Documents 3 and 4, since the molten mass is formed in close contact with the flocked base, resin leakage is less likely to occur than in the in-mold method of Patent Document 1, and the outer peripheral edge of the flocked base of the toothbrush The distance from the flock hole to the flock hole can also be shortened.

  On the other hand, the methods described in Patent Documents 3 and 4 can make the hair bundle easily reach the back of the back teeth by shortening the distance between the peripheral edge of the flocked base and the flocked hole, particularly on the tip side of the toothbrush. Thus, the operability of the toothbrush is good, but the edge portion on the tip side of the toothbrush has a curved shape protruding in the tip direction, so that the integrity of the flocked base portion and the back surface molding portion may be reduced at the tip portion.

  The present invention has excellent operability with a toothbrush in which a flocked portion is formed by a method of integrally forming a back molding portion with a coating resin on the back side of a flocked base portion, and effectively improves the strength of the flocked portion. An object of the present invention is to provide a toothbrush capable of suppressing resin leakage during molding of the back molding part.

  The present invention provides a toothbrush having a handle portion and a flocked portion that is connected to the distal end side of the handle portion and in which a plurality of bristle bundles bundling bristles are planted, and the flocked portion stands on the back side. A flocking base having a plurality of flock holes formed in the bottom surface of the flocking recess inside the peripheral wall to be installed, and a molten mass formed by heating and melting one end portion on the flocking hole on the bottom surface of the flocking depression And a back surface molding part formed so as to cover the upper end surface of the peripheral wall of the flocked base part and the concave part for flocking, and the peripheral wall of the flocked base part is curved in a protruding direction toward the front end part of the flocked part The flocking hole has a tapered opening peripheral portion with a cross-sectional area enlarged in a taper shape toward the bottom surface of the flocking concave portion, and the peripheral wall of the tip portion having the curved peripheral portion Is the outer edge of the peripheral edge of the tapered opening of a pair of flock holes in the vicinity of the peripheral wall By providing a toothbrush having a thick portion with the largest thickness in a portion corresponding to the middle between the pair of flock holes in the region between, the thickness is increased inside the recessed portion for flocking. Achieved.

  According to the toothbrush of the present invention, the strength of the flocked portion is effectively maintained while maintaining excellent operability by the toothbrush in which the flocked portion is formed by a method of integrally forming the back molding portion with the coating resin on the back side of the flocked base portion. Therefore, the resin leakage at the time of molding of the back molding part can be suppressed.

(A) is a principal part longitudinal cross-sectional view of the flocked part along the longitudinal direction of the toothbrush which concerns on preferable one Embodiment of this invention, (b) is a principal part cross-sectional view of the flocked part along the width direction. . (A) A top view of a flocked base for explaining the configuration of a toothbrush according to a preferred embodiment of the present invention, (b) is an enlarged view of part A of (a), and (c) is along BB of (b). It is sectional drawing of the state after forming the back surface shaping | molding part. (A) is sectional drawing of the metal mold | die used for the process of manufacturing a toothbrush main body, (b) is sectional drawing of a toothbrush main body. It is a principal part longitudinal cross-sectional view explaining the process of inserting a hair | bristle bundle in the flock hole of a flocking base. It is a principal part longitudinal cross-sectional view explaining the process of heat-melting the one end part which protrudes in the back side of the flocking base part of the hair | bristle bundle inserted in the flocking hole, and forming a molten lump. It is a principal part longitudinal cross-sectional view explaining the process of shape | molding a back surface shaping | molding part on the back side of a flocking base. It is a top view which illustrates other preferred embodiment of a flocking base. It is a top view which illustrates other preferred embodiment of a flocking base. It is a top view which illustrates other preferred embodiment of a flocking base. It is a top view which illustrates the flock base of the comparative example in which the thick part is not formed.

  A toothbrush 10 according to a preferred embodiment of the present invention shown in FIGS. 1 (a) and 1 (b) has a flocked base 12 (FIG. 3 (b)) of a pre-formed toothbrush body 11 as shown in FIGS. ))) Is inserted into the plurality of flock holes 13 (see FIG. 4), and the bristles 14 inserted into the flock holes 13 protrude to the back side of the flock base 12. A flocked base portion is formed by heating the one end portion 14a, which is a portion, to form a molten lump 15 (see FIG. 5), covering the formed molten lump 15 and filling and curing a coating resin on the back side of the flocked base portion 12. 12 is manufactured by a method in which a back surface forming portion 16 is formed integrally with 12 and a flocked portion (head portion) 17 of the toothbrush 10 is formed. The toothbrush 10 according to the present embodiment maintains the excellent operability by not increasing the distance between the peripheral edge of the flocked part 17 and the straight hair hole 13, that is, the distance between the peripheral edge of the flocked part 17 and the hair bundle 14. 12 by increasing the thickness of the peripheral wall 19 provided to form the flocking recess 20 on the back surface side of the twelve, particularly at the tip side of the flocking base 12, thereby improving the strength of the flocking base 12. It has a function of preventing the coating resin filled at the time of molding the back molding part 16 from leaking from the flock holes 13.

  As shown in FIGS. 1 (a) and 1 (b), the toothbrush 10 of the present embodiment is provided with a plurality of bristles 14 formed by bundling bristles connected to the handle 18 and the distal end side of the handle 18. The flocked portion 17 is a toothbrush base portion in which a plurality of flocked holes 13 are formed in the bottom surface 20a of the flocked recess 20 inside the peripheral wall 19 standing on the back side. 12, a hair bundle 14 having a molten mass 15 arranged on the flocked hole 13 and heated and melted at one end portion 14 a (see FIG. 4) on the bottom surface 20 a of the flocked recess 20, and the peripheral wall 19 of the flocked base portion 12. The back molding part 16 shape | molded covering the upper end surface 19a and the recessed part 20 for flocking is provided. As shown in FIG. 2 (a), the peripheral wall 19 of the flocked base 12 is provided with a curved peripheral portion 21 that protrudes and curves in the front end direction at least at the front end portion of the flocked portion 17, and the flocked hole 13 has the flocked base portion. 12 includes a cylindrical portion 13b having a substantially equal cross-sectional area from the top to the bottom, and a tapered opening peripheral portion 13a having a cross-sectional area enlarged in a tapered shape on the bottom surface 20a of the flocking recess 20 (FIG. 1A ) And (b)). The peripheral wall 19 of at least the front end portion including the curved peripheral edge 21 is in a region between the outer edges of the tapered opening peripheral portions 13a ′ and 13a ′ of the pair of front end flock holes 13 ′ and 13 ′ in the vicinity of the peripheral wall 19. In addition, a thick portion 22 having the largest thickness is provided at a portion corresponding to the middle between the pair of flock holes 13 ′ and 13 ′. The thick portion 22 is preferably formed so that the thickness gradually increases toward a portion corresponding to the middle of the pair of tip flock holes 13 ′ and 13 ′ in the vicinity of the peripheral wall 19 of the tip portion. It is preferably formed so as to have a shape along the outer edge of the tapered opening peripheral edge portions 13a ′ and 13a ′ of the pair of tip flocking holes 13 ′ and 13 ′ in the vicinity of the peripheral edge wall 19 of the front end portion. It is preferably formed by an intermediate convex part protruding inside the concave part 20 for flocking (see FIG. 7). Here, the portion corresponding to the middle of the pair of tip flock holes 13 ′ and 13 ′ on the peripheral wall 19 is a line extending vertically from the midpoint of the line connecting the centers of the pair of flock holes 13 ′ and 13 ′. The part of the peripheral wall 19 is said.

  In the present embodiment, the pair of tip flocking holes 13 ′ and 13 ′ in the vicinity of the peripheral wall 19 of the tip portion including the curved peripheral portion 21 are symmetrical positions with the longitudinal center line of the flocked base portion 12 as the symmetry axis. However, as shown in FIG. 9, a flocked hole 13 ′ is provided on the longitudinal center line of the flocked base 12 at the tip, and flocked holes 13 ″, 13 on both sides in the circumferential direction of the flocked hole 13 ′. A thick wall portion 22 may be provided between the two.

  In this embodiment, as shown to Fig.2 (a), the inner wall surface of the peripheral wall 19 of the front-end | tip part provided with the curved peripheral part 21 is made into a pair of front-end flock holes 13 'in the vicinity of the peripheral wall 19 of the said front-end | tip part. , 13 ′ are formed in regions that do not overlap with the tapered opening peripheral portions 13a ′, 13a ′. Specifically, the inner wall surface of the peripheral wall 19 of the distal end portion including the curved peripheral edge 21 is a surface perpendicular to the longitudinal center line of the flocked base 12 and stands along the chord direction of the curved peripheral edge 21. By forming the peripheral edge portion 19 between the outer edges of the tapered opening peripheral portions 13a 'and 13a' of the pair of tip flocking holes 13 'and 13' without expanding the curved peripheral portion 21 of the peripheral wall 19 outward. In the region, a thick portion 22 having a thicker thickness toward the inner side of the flocking recess 20 is formed.

  As shown in FIGS. 2B and 2C, the toothbrush 10 according to the present invention has a flocked portion 17 on the outer peripheral surface of the flocked portion 17 and the inner surface of the tube portion 13b ′ of the flocked hole 13 ′. The distance d1 between the first portion and the nearest portion is preferably 0.5 to 2 mm, and more preferably 0.6 to 1 from the viewpoint of narrowing the distance between the peripheral edge of the flocked portion 17 and the hair bundle 14 at the tip portion. 0.5 mm is preferable, and 0.75 to 1.25 mm is particularly preferable. Here, the distance d1 is the bottom surface of the flocked base 12 and the flocked surface from which the bristles 14 of the toothbrush 10 come out, that is, the vicinity of the surface opposite to the back molding portion 16, and the flocked portion where R is not formed. The distance from the position of the outer peripheral surface 17 to the tube portion 13b ′ of the tip flocking hole 13 ′. By shortening the distance d1, when the toothbrush 10 is used in the oral cavity, the hair bundle 14 reaches as much as the position where the tip of the flocked base 12 reaches, and the operability of the toothbrush 10, especially when brushing the back teeth The operability is improved.

  In the toothbrush 10 of the present invention, it is preferable that a plurality of flocked holes 13 are arranged along the peripheral wall 19 except for the rear end portion in the vicinity of the handle portion as well as the front flocked hole 13 ′. The distance between the outer peripheral surface of the flocked portion 17 and the outer peripheral surface of the flocked portion 17 on the inner surface of the tubular portion 13b is preferably 0.5 to 2 mm. The thickness is preferably 0.6 to 1.5 mm, particularly preferably 0.75 to 1.25 mm. Thus, by arranging the flock holes 13 side by side along the peripheral wall 19, the operability of the toothbrush 10 in the oral cavity is improved.

  The toothbrush 10 of this embodiment is manufactured according to the following manufacturing processes, for example, as shown in FIGS. That is, first, the toothbrush main body 11 as shown in FIG. In order to form the toothbrush main body 11, as shown in FIG. 3A, a mold 31 having a cavity 31 corresponding to the form of the toothbrush main body 11 and a resin injection path 32 leading to the cavity 31 is used. Then, the molding die 30 is set in a known injection molding apparatus (not shown), the thermoplastic resin is injected in a molten state from the resin injection path 32 into the cavity 31 with a predetermined injection molding pressure, cooled, and then removed. Type. By subjecting the molding die 30 to predetermined processing, a tapered opening of a pair of tip flocking holes 13 ′ and 13 ′ is formed in the curved peripheral edge 21 of the tip portion of the flocked base portion 12 of the molded toothbrush body 11. In the portion between the outer edges of the peripheral edge portions 13a ′ and 13a ′, the thickness increases toward the inside of the flocking recess 20 and the thickest portion 22 has the largest thickness in the middle of the flocking holes 13 ′ and 13 ′. It can be formed easily (see FIG. 2A).

  Here, as a thermoplastic resin for forming the toothbrush main body 11, various thermoplastic resins conventionally used for the toothbrush main body can be used. For example, polyolefin such as polypropylene, polyester such as polycarbonate and polyethylene terephthalate, polymethyl methacrylate, acrylonitrile-styrene copolymer, and acrylonitrile-butadiene-styrene copolymer can be used.

  Next, as shown in FIG. 4, a hair bundle 14 formed by bundling a plurality of bristles is inserted into the flock hole 13 of the flocked base portion 12 of the formed toothbrush body 11. There is no restriction | limiting in particular in the insertion method of the hair | bristle bundle 14, Various well-known insertion methods, such as the method using an insertion sleeve, are employable. Further, the hair bundles 14 are aligned and arranged by inserting the hair bundles 14 into the hair transplant holes 13 in a state where the hair root base 12 of the toothbrush body 11 is positioned in the hair bundle holding jig 34 having the hair bundle holding holes 33. It becomes possible to arrange | position easily in each flock hole 13 in a state. In the present embodiment, the cross-sectional shape of the flock hole 13 may be elliptical, but is preferably circular as shown in FIG.

  Here, as the bristle that constitutes the hair bundle 14, a conventional material that has been conventionally used can be used, but a different type of resin from the resin that forms the toothbrush body 11 in terms of cleanability and the like. It is preferable to use a bristle made of polyamide such as nylon or polyester such as polybutylene terephthalate.

  After inserting the hair bundle 14 into the flock hole 13 of the flocking base 12, as shown in FIG. 5, the one end portion 14 a (see FIG. 4) that is a portion protruding to the back side of the flocking base 12 of the hair bundle 14 is heated. As a result, a molten mass 15 is formed. As a heating method for heating and melting the one end portion 14a, various known heating methods such as a method of heating with a non-contact heat source using a laser heating device can be employed. As the non-contact heat source of the heating device, a laser oscillator that emits a laser beam, a halogen lamp that collects and emits light from a light source, or the like can be used. In the present embodiment, the molten mass 15 is formed by irradiating a laser beam.

  In the present embodiment, since the tapered opening peripheral portion 13a of the flocked hole 13 whose cross-sectional area is increased in a tapered shape is formed on the bottom surface 20a of the flocking recess 20 on the back side of the flocked base portion 12, this taper. The molten lump 15 is firmly fused to the tapered surface of the peripheral edge portion 13a of the opening and the flock holes 13 are closed without gaps, so that the back surface side of the flocked base portion 12 is filled with a coating resin and the back molding portion 16 is molded. At this time, it is possible to effectively avoid the resin from leaking out from the gap between the flock holes 13 due to the filling pressure, and the hair bundle 14 is integrated by the molten mass 15. Moreover, the average of the space | interval of adjacent flock holes 13 is that the periphery of the molten lump 15 of adjacent flock holes 13 is continuous or close, and is filled with a coating resin from the back side of the flock base 12 to form the back molding portion 15. From the viewpoint of suppressing the coating resin from leaking out into the flock hole 13 from the gap between the molten mass 15 and the bottom surface 20a of the flocking recess 20, the thickness is preferably 0.3 to 1.5 mm. It is preferable that it is 5-1.2 mm, and it is especially preferable that it is 0.7-1.2 mm. In particular, the distance between adjacent flock holes 13 at the tip is preferably 0.3 to 1.2 mm, more preferably 0.5 to 1.1 mm, and particularly preferably 0.7 to 1.1 mm. Is preferred.

  When the molten lump 15 is formed on the back side of the flocked base 12, as shown in FIG. 6, the back side of the flocked base 12 is filled with a coating resin, and the upper end surface 19a of the peripheral wall 19 of the flocked base 12 and the recessed portion for flocking 20 is formed. In order to form the back surface forming portion 16, for example, after positioning the flocked base portion 12 of the toothbrush body 11 to which the bristles 14 are fused to the back surface forming mold 36, the covering resin is applied with a predetermined filling pressure. The back side of 12 is filled. The coating resin is preferably the same resin as the thermoplastic resin used for the toothbrush body 11 and the flocked base 12 from the viewpoint of improving the integrity with the toothbrush main body 11 and the flocked base 12.

  When the coating resin filled on the back surface side of the hair transplant base 12 is cured and the back molding portion 16 is molded, the hair transplant portion 17 formed from the back surface forming mold 36 is removed and trimming or the like is performed as necessary. Process of a process is performed and manufacture of the toothbrush 10 is completed.

  Here, in this embodiment, the flocked base 12 of the toothbrush main body 11 (see FIG. 3B) formed using the molding die 30 (see FIG. 3A) is shown in FIGS. As shown in FIG. 2B and FIG. 2A, the pattern portion 18 of the tube portion 13b of the flocked hole 13 closest to the handle portion 18 from the tip is defined as the flocked base portion 12 where the back molding portion 16 is formed by overlapping. The length L in the longitudinal direction to the end on the side is preferably 10 to 30 mm, more preferably 15 to 25 mm. Further, the lateral width B in the direction perpendicular to the longitudinal direction is formed so as to have an oval planar shape with a size of 6 to 20 mm, but may be an elliptical shape with the major axis direction being a length L. The lateral width B is further preferably 8 to 15 mm, and particularly preferably 8 to 12 mm. The flocked base 12 has a thickness h1 of preferably 0.8 to 3 mm, more preferably 1 to 2.5 mm, and particularly preferably 1.5 to 2.2 mm. The height h3 of the peripheral wall 19 is preferably 0.1 to 1.5 mm, and more preferably 0.4 to 1.2 mm. The thickness T from the lower surface of the flocked base 12 to the upper surface of the back molding portion 16 is preferably 1.6 to 5 mm, more preferably 2 to 4.5 mm, particularly 3 to 3 from the viewpoint of operability of the toothbrush. 4 mm is preferred.

  In addition, the toothbrush body 11 of the present embodiment has a curved shape with the tip portion protruding in the tip direction, and from the lower surface of the flocked base 12 which is the thickness T of the flocked portion 17 to the upper surface of the back molding portion 16. As for the thickness T, it is preferable that the thickness T2 of the tip portion is smaller than the thickness T1 in the vicinity of the handle of the toothbrush body 11. The difference between T1 and T2 is preferably 1 mm or less, and preferably 0.2 to 0.7 mm. By reducing the thickness of the toothbrush body 11 at the distal end portion, the toothbrush body 11 can be easily inserted to the back of the back teeth. On the other hand, when the thickness T2 of the tip portion of the toothbrush main body 11 is reduced, the thickness (h3 + h2) of the back molding portion 16 is reduced. And the thickness b of the top | upper surface of the peripheral wall 19 in a front-end | tip part is the point which narrows the space | interval of the hair | bristle bundle 14 and the peripheral wall 19 in a front-end | tip part. In the peripheral wall 19 of the part where the distance between 13 ′ and 13 ′ is the closest, it is preferably 0.2 to 0.45 mm, and more preferably 0.25 to 0.4 mm. On the other hand, the thickness s of the thickest portion 22 of the peripheral wall 19 of the tip portion is preferably 0.6 to 1.5 mm, and more preferably 0.65 to 1.25 mm. It is preferable that

  And according to the toothbrush 10 of this embodiment provided with the above-mentioned structure by which the flocked part 17 was formed by the above-mentioned manufacturing method, the space | interval of the hair | bristle bundle 14 and the peripheral wall 19 is narrowed in the front-end | tip part of the toothbrush 10. In addition, the thickness T of the toothbrush 10 can be reduced, and the strength of the tip portion is effectively improved while maintaining excellent operability. Can be prevented from leaking.

  That is, according to the toothbrush 10 of the present embodiment, the peripheral wall 19 of the flocked base 12 includes the curved peripheral portion 21 that protrudes and curves in the front end direction at the front end portion of the flocked portion 17, and the peripheral wall of this front end portion 19 is thicker inwardly at a portion between the outer edges of the tapered opening peripheral portions 13a ′ and 13a ′ of the pair of tip flocking holes 13 ′ and 13 ′ in the vicinity of the peripheral wall 19, and the flocking hole 13 Since the thick portion 22 having the largest thickness is provided in a portion corresponding to the middle of ', 13', particularly at the tip portion of the toothbrush 10, the gap between the peripheral edge of the flocked portion 17 and the bristles 14 in the outer peripheral portion is provided. It is possible to increase the area of the upper end surface of the peripheral wall 19 of the flocked base 12 without widening the interval, thereby improving the integrity of the flocked base 12 and the back molding portion 16.

  Further, in the present embodiment, the taper of the tip flocking holes 13 ′ and 13 ′ of the flocked base portion 12 increases particularly as the thickness of the thick wall portion 22 of the peripheral wall 19 of the flocked base portion 12 increases at the tip portion of the toothbrush 10. The distance between the outer edge of the peripheral edge portions 13a 'and 13a' and the peripheral wall 19 is reduced, and the peripheral edge of the molten mass 15 at one end 14a of the hair bundle 14 is close to or continuous with the peripheral wall 19, It is possible to prevent the coating resin when molding the molding part 16 from leaking into the flock hole 13 ′ from between the bottom surface 20 a of the flocking recess 20 and the molten mass 15 on the peripheral wall 19 side from the periphery of the molten mass 15. it can.

  In the present embodiment, the thick portion 22 is provided on the peripheral wall 19 of the tip portion of the toothbrush 10 including the curved peripheral portion 21. Therefore, while reducing the distance d1 between the bristle bundle 14 and the outer peripheral edge of the toothbrush, the integrity of the flocked base 12 and the back surface molded portion 16 is improved, and the coating resin when forming the back surface molded portion 16 is the flock hole. Leaking from 13 'can be effectively prevented. In particular, even when the thickness of the tip portion of the toothbrush 10 is reduced, the integrity (peeling strength) between the flocked base portion 12 and the back molding portion 16 at the tip portion can be ensured.

  FIG. 7 illustrates another preferred embodiment of the flocked base 12 ′ used in forming the flocked portion 17 of the toothbrush 10. The hair transplant base 12 ′ shown in FIG. 7 has substantially the same configuration as that of the hair transplant base 12 of the above embodiment, but in the hair transplant base 12 ′ shown in FIG. An intermediate convex portion protruding inward so as to have a shape along the outer edge of the tapered opening peripheral edge portions 13a ′ and 13a ′ of the pair of flocking holes 13 ′ and 13 ′ in the vicinity of the peripheral edge wall 19 of at least the tip portion provided. 23. According to the flocked base 12 ′ shown in FIG. 7, the top surface area of the peripheral wall 19 can be further increased, particularly at the tip portion of the toothbrush 10, so that the flocked base 12 ′ and the back molding portion 16 described above are used. And the peel strength can be improved. Moreover, as for the molten lump 15 formed in a pair of flocking holes 13 'and 13', the periphery of the molten lump 15 continues with the peripheral wall 19 in the front end side, and the bottom face 20a of the molten lump 15 and the recessed part 20 for flocking It is possible to prevent the coating resin from leaking when the back surface molding portion 16 is molded from between.

  FIG. 8 illustrates still another preferred embodiment of the flocked base 12 ″ used when forming the flocked portion 17 of the toothbrush 10. The flocked base 12 ″ shown in FIG. The hair transplant base 12 ″ shown in FIG. 8 has substantially the same configuration as the base 12, but includes the peripheral wall 19 including the peripheral wall 19 of the distal end portion including the curved peripheral edge 21. A thick-walled portion formed by an intermediate convex portion 24 projecting inside the concave portion 20 for flocking so as to have a shape along the outer edge of the tapered opening peripheral edge portions 13a, 13a of each pair of flocking holes 13, 13 in the vicinity of 19 22 "is formed. According to the flocked base 12 ″ shown in FIG. 8, it becomes possible to increase the area of the top surface of the peripheral wall 19 over the entire circumference of the toothbrush 10 as well as the tip portion of the toothbrush 10. The function of improving the strength can be exhibited more effectively.

  FIG. 9 illustrates another preferred embodiment of the flocked base portion 12x used when forming the flocked portion 17 of the toothbrush 10. FIG. The hair transplant base 12x shown in FIG. 9 has substantially the same configuration as the hair transplant base 12 shown in FIG. 2 (a). However, the hair transplant base 12x shown in FIG. 9 has a peripheral wall including a curved peripheral edge 21 at the tip. Corresponding to the curved shape protruding toward the tip of 19, a flocked hole 13 ′ is formed on the central axis extending in the longitudinal direction of the flocked base 12 x, and the direction along the peripheral wall 19 on both sides of the flocked hole 13 ′ Two flocking holes 13 "and 13" arranged side by side are formed. The thick wall portion 22x of the peripheral wall 19 is formed in the peripheral wall 19 in the region between the flocked hole 13 'and the flocked holes 13 "on both sides, and the thick wall portion 22x is formed between the flocked hole 13' and the flocked hole. The thickness gradually increases toward a position corresponding to the center of 13 ″. Thereby, while being able to exhibit the function (function to improve peeling strength) which improves the integrity of the flock base 12x and back molding part 16 in a tip part, molten mass of flock hole 13 'and flock hole 13' ' 15, the peripheral edge of the molten mass 15 can be continuous with the peripheral wall 19 in the vicinity of the peripheral wall 19, and the resin leakage suppressing effect can be improved.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the flocked base portion does not necessarily have to be formed to have a substantially oval planar shape, and includes a curved peripheral portion that protrudes in the distal direction at least at the distal end portion of the flocked portion, such as a substantially circular shape or a substantially oval shape. Other various planar shapes can also be formed.

  Hereinafter, although the toothbrush of this invention is demonstrated in detail by an Example and a comparative example, this invention is not limited to these.

About a toothbrush (Example 1) provided with the flocked base shown in FIG. 2 (a), a toothbrush (Example 2) provided with the flocked base shown in FIG. 8, and a toothbrush (Comparative Example 1) provided with the flocked base shown in FIG. The peel strength test at the tip and evaluation for resin leakage suppression were performed.
<Configuration of each toothbrush>
The toothbrush of Example 1 has the configuration shown in FIG. 2A, and the bristle bundle is polybutylene terephthalate, and the flocked base portion 12, the back surface molded portion 16, and the handle portion 18 are molded from polypropylene. Further, the distance L from the end of the flocked hole 13 closest to the handle 18 of the flocked base 12 to the tip of the flocked base 12 is 20 mm, and the width B in the short axis direction of the flocked base 12 ( The widest width B) is 10 mm, the average thickness h1 from the bottom surface 20a of the flocking recess 20 of the flocking base 11 to the lower surface of the flocking base 11 (the flocking surface opposite to the back molding portion 16) is 2 mm, and the average of the peripheral wall 19 The height h is 1 mm, the thickness T from the lower surface (planted surface) of the flocked base 11 to the upper surface of the back molding portion 16 is 4 mm, the thickness T1 on the handle portion 18 side is 3. 5 mm (see FIGS. 1A and 1B). The diameter of the flocked hole 13 was 1.4 mm, the average distance between adjacent flocked holes 13 was 1 mm, and the diameter of the peripheral edge of the tapered opening of the flocked hole 13 was 1.9 mm. Further, the width b of the top surface of the peripheral wall was an average of 0.4 mm in the portion where the thick portion 22 was not formed.
In the toothbrush of Example 1, the thickness s of the thick portion 22 at the tip portion was 0.7 mm.
The toothbrush of Example 2 is the structure shown in FIG. 8, Comprising: Except for the point which formed the thick part 22 and the point which formed the thick part 22 in the perimeter, it is the same structure as Example 1. The width s of the thick portion 22 was 1.23 mm.
The toothbrush of the comparative example 1 is the structure represented by FIG. 10, Comprising: Except not providing the thick part 22, it is the same structure as Example 1. FIG.

<Peel strength test>
The peel strength was measured by the following method.
(1) The bristles 14 of the pair of flock holes 13 ′ and 13 ′ in the vicinity of the peripheral wall 19 at the tip of the molded toothbrush (toothbrushes shown in FIGS. 2, 8, and 10) are removed from the molten mass 15. I pulled it out with pliers to pull it out. The hair bundle of the other flock hole 13 was cut along the surface of the flock base 12.
(2) The flock holes 13 ′ and 13 ′ were faced up, and the back molding part 16 was supported by pressing from the side and indicated horizontally.
(3) A pin substantially the same as the hole diameter of the flocked hole 13 'was inserted into both flocked holes 13' and 13 ', and pressure was applied to the flocked base 12 from above via the pin. The pressure was measured with a digital force gauge (IMADA high performance type digital force gauge ZP-1000N) fixed to a measurement stand, and the load (kg) when the flocked base 12 was peeled from the back molding portion 16 was measured.
(4) Table 1 shows the average peel strength of 10 toothbrushes for each of the examples and comparative examples.

<Evaluation of molten mass>
Evaluation of the molten lump was performed by visually observing the peripheral state of the molten lump 15 at one end of the hair bundle 14 of the flocked holes 13 'and 13'. The molten lump 15 of the hair bundle 14 is continuous at the distal end of the flocked base 12 and the periphery of the molten lump 15, so that the resin filled for the back surface molded body is formed from the flocked holes 13 ′ and 13 ′. Leakage makes it difficult to be exposed on the flocked surface. Therefore, the evaluation was made based on the degree of the gap between the peripheral edge on the front end side of the flock hole 13 ′ of the molten mass 15 at the front end portion and the peripheral wall 19. For two flocking holes 13 'and 13' of each of the ten toothbrushes of Examples 1 and 2 and Comparative Example 1, that is, 20 flocking holes 13 ', the planted portion where the tip side of the molten mass 15 is continuous with the peripheral wall The number of pores 13 'is shown in Table 1.

  Table 1 shows the peel strength tests of the toothbrushes of Examples 1 and 2 and Comparative Example 1 and the evaluation of the molten mass. As shown in Table 1, it can be seen that the toothbrushes of Examples 1 and 2 have higher peel strength than the toothbrush of Comparative Example 1, and the integrity of the flocked base portion 12 and the back molding portion 16 is high. Further, in Examples 1 and 2, the peripheral edge of the molten mass 15 reaches the peripheral wall 19 on the tip side of the molten mass 15, and the coating molding resin moves to the flock holes 13 ′ and 13 ′ at the time of molding the back surface molding portion 16. Resin leakage can be suppressed.

DESCRIPTION OF SYMBOLS 10 Toothbrush 11 Toothbrush main body 12,12 ', 12 "Flocking base part 13 Flocking hole 13' Tip flocking hole 13a, 13a 'Tapered opening peripheral part 13b, 13b' Cylindrical part 14 Hair bundle 14a One end part 15 Molten lump 16 Back surface molding part 17 Flocked portion 18 Handle portion 19 Peripheral wall 20 Flocked recess 20a Bottom surface 21 of flocked recessed portion Curved peripheral portions 22, 22 ', 22 "Thick portion 23, 24 Intermediate convex portion

Claims (5)

A toothbrush having a handle portion and a flocked portion continuously provided on the distal end side of the handle portion, in which a plurality of hair bundles formed by bundling bristles are planted,
The flocked portion is formed by a flocked base portion in which a plurality of flocked holes are formed in the bottom surface of a flocked concave portion on the inner side of a peripheral wall standing on the back side, and one end portion that is arranged in the flocked hole and heated and melted. The hair bundle having a molten mass on the bottom surface of the recessed portion for flocking, and a back molding portion formed so as to cover the upper end surface of the peripheral wall of the flocked base and the recessed portion for flocking,
The peripheral wall of the flocked base is provided with a curved peripheral portion that protrudes and curves in the front end direction at the front end portion of the flocked portion,
The flocking hole has a tapered opening peripheral edge with a cross-sectional area enlarged in a taper shape toward the bottom surface of the concave portion for flocking,
The peripheral wall of the distal end portion including the curved peripheral edge portion is thickened inside the recessed portion for flocking in a region between the outer edges of the tapered opening peripheral edge portions of the pair of flock holes in the vicinity of the peripheral wall. A toothbrush comprising a thick part having the largest thickness in a portion corresponding to the middle of the pair of flock holes.   In the tip portion of the flocked portion, the distance between the outer peripheral surface of the flocked portion and the portion closest to the outer peripheral surface of the flocked portion of the inner wall of the cylindrical portion where the tapered portions of the pair of flocked holes are not formed is The toothbrush according to claim 1, wherein the toothbrush is 0.5 to 2 mm.   The thick-walled portion protrudes inside the recessed portion for flocking so as to have a shape along the outer edge of the tapered opening peripheral portion of the pair of flocked holes in the vicinity of the peripheral wall of the tip portion including the curved peripheral portion. The toothbrush of Claim 1 or 2 currently formed by the intermediate | middle convex part.   The middle protruding to the inside of the recessed portion for flocking so as to have a shape along the outer edge of the peripheral edge of the tapered opening of each pair of flocking holes in the vicinity of the peripheral wall over the entire circumference of the peripheral wall The toothbrush of any one of Claim 1 to 3 in which the thick part by the convex part is formed. The toothbrush according to any one of claims 1 to 4, wherein a thickness of the flocked portion is smaller at a tip portion than a thickness near the handle portion.

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