toothbrush

Abstract

A toothbrush according to the present invention has at least a head part having a brush part on the front surface thereof, wherein: the brush part has a plurality of soft resin parts standing upright from the front surface; each of the soft resin parts includes a shaft section that stands upright with respect to the front surface, an enlarged section formed on the tip end side of the shaft section, and a narrow constricted section that is formed at the boundary between the shaft section and the enlarged section and that is at least narrower than the enlarged section; and the height of the shaft sections is taller than the height of the enlarged sections in a normal direction of the front surface.

Description

[Technical Field]

[0001] The present invention relates to a toothbrush. This application claims priority based on Japanese Patent Application No. 2020-216667, filed on December 25, 2020, the contents of which are incorporated herein by reference. [Background technology]

[0002] In recent years, toothbrushes have been required to have a basic configuration that not only cleans the oral cavity but also massages the gums. Conventional techniques include arranging the bristle bundles on the outer periphery of the brush head in a C-shape, etc., to improve the massage effect. Several other toothbrush structures have also been proposed that aim to achieve both a cleaning effect on the tooth surfaces and cervical areas and a massage effect on the gums (see, for example, Patent Document 1).

[0003] However, no technology has been disclosed that focuses on the gentle feel on the gums when it comes to toothbrushes that take into account the massaging effect on the gums. In other words, it has been difficult to achieve both a massaging effect on the oral cavity (gums) and a gentle feel on the oral cavity (gums). Furthermore, there are limitations to achieving a massage effect on the oral cavity (gums) and a gentle feel using only bristles. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2000-300347 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in consideration of the above points, and has as its object to provide a toothbrush that can enhance both the massaging effect on the oral cavity and a gentle feel. [Means for solving the problem]

[0006] In one embodiment of the present invention, the toothbrush has at least a head portion having a brush portion on the front surface, the brush portion having a plurality of soft resin portions standing up from the front surface, the soft resin portions having a shaft portion standing up from the front surface, an enlarged portion formed at the tip side of the shaft portion, and a narrowed portion formed at the boundary between the shaft portion and the enlarged portion and which is at least narrower than the enlarged portion, and in the direction normal to the front surface, the height of the shaft portion is greater than the height of the enlarged portion.

[0007] According to the configuration of this embodiment, by providing an enlarged portion at the tip of the soft resin portion to increase the contact area with the oral cavity, it is possible to improve the gentleness of contact with the oral cavity. Furthermore, by providing a narrowed portion that is thinner than the expanded portion at the boundary between the stem portion and the expanded portion, it is possible to cause the expanded portion to bend appropriately relative to the stem portion, starting from the narrowed portion. Furthermore, because the length of the stem is longer than the length of the expansion section in the direction normal to the front of the head, the entire stem can be bent appropriately, which enhances both the oral cavity massaging effect of the soft resin section and the gentle feel on the oral cavity.

[0008] In one form of the toothbrush of the present invention, the shaft portion may be configured so that at least the tip side in the normal direction connecting to the constricted portion becomes thinner toward the constricted portion, and the expanded portion becomes thicker as it moves away from the constricted portion and then becomes thinner again from the position of maximum shaft width toward the tip. With this configuration, the tapered shape of the shaft makes the entire shaft more flexible. Furthermore, by making the shape of the expanded portion thicker as it moves away from the constricted portion and then tapering again from the point of maximum shaft width toward the tip, the contact area of ​​the expanded portion with the oral cavity is increased, and the expanded portion is more flexible starting from the constricted portion, thereby further enhancing both the massage effect on the oral cavity and the gentle feel inside the oral cavity.

[0009] In the toothbrush according to one aspect of the present invention, the enlarged portion may be spherical. This configuration makes it easy to mold, and can enhance both the massaging effect on the oral cavity and the gentle feel on the oral cavity.

[0010] In one embodiment of the toothbrush of the present invention, the maximum axial width of the enlarged portion may be within the range of 1.0 mm to 4.0 mm, the minimum axial width of the constricted portion may be within the range of 0.8 mm to 3.0 mm, and the maximum axial width of the axial portion may be within the range of 1.0 mm to 4.0 mm. According to this configuration, the constricted portion is thinner than the expanded portion and the shaft portion, and the expanded portion is more likely to bend from the constricted portion. Furthermore, by setting the maximum axial width of the expansion portion and the maximum axial width of the shaft within the above ranges, it becomes possible to achieve moderate flexibility and moderate contact with the oral cavity, thereby improving the balance between the massaging effect of the soft resin portion on the oral cavity and the gentle feel of the soft resin portion on the oral cavity.

[0011] In one embodiment of the toothbrush of the present invention, when the maximum cross-sectional area of ​​the shaft portion is X, the minimum cross-sectional area of ​​the constricted portion is Y, and the maximum cross-sectional area of ​​the expanded portion is Z, the value of Y / X may be within the range of 0.2 to 0.75, and the value of Z / X may be within the range of 0.25 to 2.0. With this configuration, it is possible to transmit the stiffness of the base side of the soft resin portion to the tip, thereby achieving a sufficient massaging effect on the oral cavity.

[0012] In one embodiment of the toothbrush of the present invention, the minimum distance between the shaft portions of the adjacent soft resin portions may be within a range of 0.5 mm to 2.0 mm, and the minimum distance between the enlarged portions may be within a range of 0.5 mm to 2.0 mm. According to this configuration, the enlarged portions of the adjacent soft resin portions are less likely to come into contact with each other, and a decrease in the comfort of contact with the oral cavity can be prevented.

[0013] In one embodiment of the toothbrush of the present invention, the toothbrush comprises a plurality of blocks each having a base portion connecting the base ends of the soft resin portions and the head portion having a first region in which a plurality of bristle bundles are planted and a plurality of second regions in which the blocks are arranged, and the sum of the widths of the second regions relative to the overall width of the head portion may be in the range of 10.0% or more and 50.0% or less. With this configuration, the multiple blocks can apply a sufficient load when they come into contact with the oral cavity during brushing, thereby achieving a sufficient massaging effect on the oral cavity. Furthermore, by providing multiple blocks, the multiple soft resin parts in each block come into contact with the gums, distributing the load on the gums and improving the comfort of the brush.

[0014] In one aspect of the toothbrush of the present invention, the sum of the maximum cross-sectional areas of the enlarged portions may be in the range of 15.0% to 70.0% of the total area of ​​the plurality of second regions. With this configuration, the soft resin portion bends appropriately during brushing, and when it comes into contact with the gums, a sufficient load is applied, thereby achieving both a massaging effect on the oral cavity and a comfortable feel.

[0015] In the toothbrush according to one aspect of the present invention, the total area of ​​the plurality of second regions may be smaller than the area of ​​the first region. According to this configuration, the area of ​​the first region is sufficiently large relative to the total area of ​​the plurality of second regions, so that it is possible to achieve both a good cleaning effect and a comfortable feel.

[0016] In the toothbrush according to one aspect of the present invention, the density of the bristle bundles in the first region may be greater than the density of the soft resin portions in the second regions. With this configuration, the density of the bristle bundles is greater than the density of the soft resin part in the head portion, so that a sufficient number of bristle bundles can be secured in the brush portion, thereby ensuring effective cleaning within the oral cavity.

[0017] In the toothbrush according to one aspect of the present invention, the area of ​​the first region may be larger than the sum of the maximum cross-sectional areas of the enlarged portions in the plurality of soft resin portions. According to this configuration, the first area is sufficiently large relative to the sum of the maximum cross-sectional areas of each expansion portion in the multiple soft resin portions, thereby ensuring a feeling of cleaning within the oral cavity while enhancing both the massage effect within the oral cavity and the gentle feel of the contact with the oral cavity.

[0018] One embodiment of the toothbrush of the present invention is a toothbrush equipped with a head portion having a brush portion on the bristle implantation surface, and comprises a head component portion that constitutes part of the head portion and is made of a first resin, a plurality of soft resin portions that constitute part of the head portion and the brush portion and are made of a second resin, and a plurality of bristle bundles provided on the head component portion, wherein the soft resin portion has a plurality of elastomer portions that constitute the brush portion and an elastomer base that connects the base ends of the plurality of elastomer portions to each other, and the elastomer base has a pair of ends on both sides in the lengthwise or widthwise direction of the head portion that are connected to the head component portion, and has a movable portion that is detached from the head component portion and can move in the thickness direction and width direction of the elastomer base.

[0019] In one aspect of the toothbrush of the present invention, the head component may have a soft resin housing portion that opens at least to the bristle implantation surface, and the soft resin portion may be arranged within the soft resin housing portion.

[0020] In one aspect of the toothbrush of the present invention, the soft resin containing portion may be configured to penetrate the head constituent portion in a thickness direction.

[0021] In one embodiment of the toothbrush of the present invention, the soft resin portion has a plurality of elastomer portions extending vertically from the front of the elastomer base, and the elastomer portions may be configured so that at least three or more are lined up in the movable portion along the length of the elastomer base.

[0022] In one embodiment of the toothbrush of the present invention, the thickness of at least the movable part of the elastomer base may be thinner than the thickness of the head component, and a space may exist on the back side of the movable part within the soft resin storage part.

[0023] In one embodiment of the toothbrush of the present invention, the head component may have a pair of hard resin side fixing portions within the soft resin accommodating portion to which the pair of ends of the soft resin portion are fixed, and the elastomer base may have second locking portions that can be locked to first locking portions formed on the pair of hard resin side fixing portions.

[0024] In one aspect of the toothbrush of the present invention, the thickness of the movable part may be preferably within a range of 0.5 mm or more and 2.5 mm or less.

[0025] In one aspect of the toothbrush of the present invention, the height of the elastomer portion from the surface of the elastomer base to the tip may be shorter than the length of the bristle bundle from the bristle implantation surface to the tip. [Effects of the Invention]

[0026] The present invention provides a toothbrush that can enhance both the massaging effect on the oral cavity and the gentle feeling on the oral cavity.The present invention also provides a toothbrush that can achieve both cleaning ability and a massaging effect. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a perspective view showing a head portion of a toothbrush according to one embodiment. [Figure 2] FIG. 2 is a front view showing a head portion of the toothbrush of one embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing the configuration of the head portion of the toothbrush according to one embodiment. [Figure 4] FIG. 4 is a front view showing the head portion of the toothbrush according to one embodiment. [Figure 5] FIG. 5 is a cross-sectional view illustrating the relationship between adjacent soft resin portions in the toothbrush of one embodiment. [Figure 6] FIG. 6 is a rear view showing the configuration of the toothbrush body of the toothbrush of one embodiment. [Figure 7] FIG. 7 is a front view showing the overall configuration of a toothbrush according to one embodiment of the present invention. [Figure 8] FIG. 8 is a side view showing the overall configuration of a toothbrush according to one embodiment of the present invention. [Figure 9] FIG. 9 is a rear view showing the overall configuration of a toothbrush according to one embodiment of the present invention. [Figure 10A] FIG. 10A is an enlarged front view of a head portion of a toothbrush according to one embodiment of the present invention. [Figure 10B] FIG. 10B is an enlarged side view of the head portion of the toothbrush according to one embodiment of the present invention. [Figure 11] FIG. 11 is a cross-sectional view taken along line VV in FIGS. 10A and 10B. [Figure 12] FIG. 12 is a cross-sectional view taken along line VI-VI in FIGS. 10A and 10B. [Figure 13] FIG. 13 is a front view showing the configuration of the toothbrush body. [Figure 14] FIG. 14 is a side view showing the configuration of the toothbrush body. [Figure 15] FIG. 15 is a rear view showing the configuration of the toothbrush body. [Figure 16]FIG. 16 is an enlarged front view of the head component of the toothbrush body. [Figure 17] FIG. 17 is a cross-sectional view taken along line XI-XI in FIG. [Figure 18] FIG. 18 is a cross-sectional view taken along line XII-XII in FIG. [Figure 19] FIG. 19 is a side view showing the configuration of a toothbrush according to one embodiment of the present invention. [Figure 20] FIG. 20 is a partial cross-sectional view showing the head component of the toothbrush shown in FIG. [Figure 21] FIG. 21 is a partial cross-sectional view showing the head component of the toothbrush shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0028] (First embodiment) An embodiment of the present invention will be described below. The following embodiment shows one aspect of the present invention, does not limit the present invention, and can be modified as desired within the scope of the technical concept of the present invention. In addition, in the following drawings, the scale and number of each structure are different from the actual structure to make each configuration easier to understand.

[0029] <Toothbrush> A toothbrush 1 according to one embodiment of the present invention will be described with reference to FIGS. In the following description, the side of the head unit 4 on which the brush unit 2 is provided is referred to as the front side (flat side), and the side opposite the side on which the front face 4a of the head unit 4 faces is referred to as the back side. In addition, the direction in which the toothbrush body 3 extends is referred to as the Z direction (long axis), the direction perpendicular to the Z direction (long axis) is referred to as the short axis direction, the X direction parallel to the front face 4a and perpendicular to the Z direction (long axis) is referred to as the width direction, and the Y direction perpendicular to the front face 4a is referred to as the thickness direction. In addition, the side on which the head unit 4 is provided is referred to as the tip side, and the side opposite the tip side (the neck portion 5 side) is referred to as the rear side.

[0030] (Brush part) As shown in FIG. 1, the brush part 2 has a bristle part 21 made up of a plurality of bristle bundles 21a, and a pair of blocks 22 having a plurality of soft resin parts 23. The brush part 21 has multiple bristle bundles 21a arranged in the center of the width direction (X direction) from the tip end to the rear end in the longitudinal direction (Z direction) of the head part 4. The multiple bristle bundles 21a may be implanted in multiple bristle implantation holes 4b opening on the front surface 4a of the head part 4 using a flat wire or the like, or may be integrally molded bristle bundles such as by insert molding.

[0031] The bristles constituting the bristle bundle 21a may be straight bristles, bristles whose diameter gradually decreases toward the tip (tapered bristles), bristles with branched ends, spiral bristles, bristles with irregular cross sections, etc. The tip shape of the bristle bundle 21a may be flat-cut, mountain-cut, convex, concave, etc. Alternatively, the bristle bundle 21a may have an offset shape with a step between half bristle bundles separated by a flat line. The type of bristles used and the tip shape of the bristle bundle 21a are appropriately determined taking into consideration the cleaning effect desired for the brush part 21 and the feel against the gums, etc.

[0032] 2, the pair of blocks 22 are provided on both sides of the head unit 4 in the width direction (X direction), one on each side outside the brush unit 21. Each block 22 is entirely made of a soft resin material.

[0033] Examples of soft resin materials that make up the block 22 include polyolefin-based thermoplastic elastomers, polystyrene-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, polyester-based thermoplastic elastomers, 1,2-polybutadiene-based thermoplastic elastomers, ethylene-vinyl acetate-based thermoplastic elastomers, polyvinyl chloride-based thermoplastic elastomers, natural rubber-based thermoplastic elastomers, fluorine-based thermoplastic elastomers, and trans-polyisoprene-based thermoplastic elastomers.

[0034] (Base 24) As shown in FIG. 1, the block 22 has a plurality of soft resin portions 23 and a base portion 24 that connects the base ends of the plurality of soft resin portions 23 and supports them.

[0035] 3, the base portion 24 is a portion that is disposed within the through-hole 4c formed in the head portion 4. The thickness of the base portion 24 is approximately the same as the thickness of the head portion 4. Therefore, the front surface 4a of the head portion 4 and the surface 24a of the base portion 24 are approximately flush with each other. As shown in FIG. 2, the planar shape of the base portion 24 is approximately the same as the planar shape of the through hole 4c on the head portion 4 side, has a length along the axial direction, and has semicircular arc shapes on the tip and rear end sides.

[0036] 1 and 3, the multiple soft resin portions 23 stand vertically from the surface 24a of the base portion 24. In this embodiment, there are four soft resin portions 23 on one side in the width direction (X direction), but the number of soft resin portions 23 is not limited to this and can be changed appropriately depending on the size of the head portion 4, etc. The total number of soft resin portions 23 (total number of pairs on both sides in the width direction (X direction)) is preferably 2 or more and 16 or less, and more preferably 2 or more and 12 or less.

[0037] The four soft resin portions 23 on one side in the width direction (X direction) are arranged at equal intervals in the length direction of the base portion 24. Of these four soft resin portions 23, the soft resin portion 23 located at the front end in the length direction of the base portion 24 and the soft resin portion 23 located at the rear end in the length direction of the base portion 24 are arranged further inward in the length direction than the front and rear ends of the base portion 24.

[0038] The soft resin portion 23 has an axial portion 23A that stands vertically from the surface 24a of the base portion 24, an expanded portion 23B formed at the tip side of the axial portion 23A, and a constricted portion 23C formed at the boundary between the axial portion 23A and the expanded portion 23B. It is preferable that the outer diameter contour lines on both sides in the width direction of the soft resin portion 23 are formed symmetrically with respect to a center line O extending in the height direction (Y direction) of the soft resin portion 23. Here, the height direction of the soft resin portion 23 coincides with the normal direction to the front surface 4a of the head portion 4. In this embodiment, the four soft resin portions all have the same shape.

[0039] (Shaft 23A) 3, shaft 23A has a tapered shape that is thickest at the base end connected to base 24 and becomes thinner toward the tip end. Furthermore, shaft 23A has a circular cross section intersecting center line O, and the diameter gradually decreases from the base end toward the tip end. In this embodiment, the maximum diameter of shaft 23A is preferably approximately equal to or different from the width of base 24.

[0040] (Enlarged section 23B) 3, the expanded portion 23B has a circular cross-sectional shape intersecting the height direction (Y direction) and an overall spherical shape. The expanded portion 23B gradually increases in diameter from the shank 23A side toward the tip end in the length direction (height direction) of the soft resin portion 23, and gradually decreases in diameter from the most expanded portion (hereinafter, thickest portion 23b) toward the tip end. Because the expanded portion 23B of this embodiment has a spherical shape, the thickest portion 23b of the expanded portion 23B is located approximately in the center of the expanded portion 23B in the length direction of the soft resin portion 23.

[0041] (23C waist) In the embodiment of Fig. 3, as shown in Fig. 5, constricted portion 23C has curve 23c1 that extends in an arc shape around center line O from the tip of stem portion 23A to the rear end of expanded portion 23B. Curve 23c1 has a center of curvature outside soft resin portion 23. The position on curve 23c1 where it begins to change from the tip side of stem portion 23A toward expanded portion 23B is defined as boundary P between stem portion 23A and expanded portion 23B. Note that, unlike the embodiment shown in FIG. 3, the constricted portion 23C may be a straight line instead of a curved arc.

[0042] The height H1 from the base end of soft resin portion 23 to boundary P (height of shaft portion 23A) is greater than the height H2 from boundary P to the tip of expanded portion 23B (H1>H2). This allows the entire soft resin portion 23 to bend appropriately in response to the bending of bristle bundle 21a, and expandable portion 23B to bend appropriately relative to shaft portion 23A, starting from constricted portion 23C. This improves the gentleness of the soft resin portion 23 when it contacts the oral cavity. The boundary P is defined based on the direction of the head portion 4 as viewed from the side.

[0043] In this embodiment, the shaft portion 23A has a tapered diameter from the base portion 23a connected to the base portion 24, and has a tapered shape over the entire height direction, but the shape is not limited to this. For example, instead of starting to taper from base 23a of shaft 23A, the diameter may start to taper from a predetermined position several millimeters away from base 23a. That is, base 23a of shaft 23A may be cylindrical. Alternatively, shaft 23A may not taper, and the entire shaft in the height direction may be cylindrical. Shank 23A may maintain the same thickness from the base end and be shaped to connect to expanded portion 23B.

[0044] In this embodiment, the shape of the expanded portion 23B is spherical, but is not limited to this shape. The shape of expanded portion 23B can be changed as appropriate to other shapes, for example, as long as it is a shape that becomes thicker from the tip of shaft portion 23A and then becomes thinner again as it approaches the tip. The cross-sectional shape and overall shape of the expanded portion 23B may be polygonal or irregular.

[0045] (Toothbrush body) The toothbrush body 3 is made of hard resin and has a head portion 4 having a brush portion 2 on the front surface 4a, a neck portion 5 extending from the head portion 4 toward the rear end in the longitudinal axis direction (Z-axis direction), and a handle portion (not shown) extending from the rear end of the neck portion 5 toward the rear end on the opposite side of the head portion 4.

[0046] Examples of hard resins that make up the toothbrush body 3 include polypropylene (PP), polyacetal (POM), polycyclohexylene dimethylene terephthalate (PCT), polyethylene terephthalate (PET), polycarbonate (PC), acrylonitrile-butadiene-styrene resin (ABS), polymethyl methacrylate (PMMA), polystyrene (PS), acrylonitrile-butadiene-styrene resin (ABS), cellulose propionate (CP), and polyarylate. Biodegradable resins, plant-derived resins, paper-blended resins, plant-blended resins, and the like may also be used. Among these, polypropylene (PP) is preferred for its excellent moldability and cost advantages.

[0047] In this embodiment, as shown in FIGS. 3 and 6, the head portion 4 of the toothbrush body 3 is formed with a pair of through holes 4c for arranging a pair of blocks 22 therein. The through holes 4c are formed on both sides of the head portion 4 in the width direction. Each through hole 4c penetrates the head portion 4 in the thickness direction (Y direction) and opens to the front surface 4a and the back surface 4d, respectively. The pair of through holes 4c is an elongated hole extending linearly along the length direction of the head portion 4, and the front and rear end sides are semicircular arc-shaped in plan view. The width of the through holes 4c is approximately the same as the width of the block 22.

[0048] 3 and 6, a fixing portion 4f for fixing a block 22 in each through hole 4c is formed inside each pair of through holes 4c. The fixing portion 4f is located approximately at the center of the length direction (Z direction) of the through hole 4c and is formed across the width direction (X direction) so as to connect the inner peripheral surfaces 4e of the through hole 4c on both sides in the width direction. Each fixing portion 4f is located approximately at the center of the thickness direction (Y direction) of the head portion 4 and is located inside away from the front surface 4a and back surface 4d of the head portion 4.

[0049] As shown in FIG. 3, the cross-sectional shape of the fixing portion 4f along the length direction (Z direction) of the head portion 4 is rectangular, but it may be circular or have any other shape. Furthermore, the number of fixing portions 4f formed in the through-hole 4c is not limited to one, but a plurality of fixing portions 4f may be provided at intervals in the length direction (Z direction) of the through-hole 4c.

[0050] As shown in FIG. 3, the through hole 4c is composed of two tapered holes 4c1 and 4c2. The first tapered hole 4c1 opens to the front surface 4a of the head portion 4, and widens outward in the axial direction (Z direction) as it approaches the front surface 4a in the thickness direction (Y direction) of the head portion 4. The second tapered hole 4c2 opens to the back surface 4d of the head portion 4, and widens outward in the axial direction as it approaches the back surface 4d in the thickness direction of the head portion 4. The first tapered hole 4c1 and the second tapered hole 4c2 are holes formed in the case of a configuration having the fixing portion 4f, and communicate with each other in the thickness direction of the head portion 4.

[0051] In this embodiment, the toothbrush body 3 is injection-molded by primary molding using a hard resin material, and then secondary molding using a soft resin material is performed to injection-molde the blocks 22 into each of the through-holes 4c of the head portion 4. During secondary molding, the blocks 22 are molded so as to surround the fixing portions 4f in the through-holes 4c, thereby maintaining the fixed state of the blocks 22 relative to the head portion 4.

[0052] In the toothbrush 1 of this embodiment, the tip of the soft resin portion 23 that comes into contact with the oral cavity has an enlarged shape (particularly a spherical shape), which increases the surface area at the tip, and the contact area with the gums, etc. is increased, improving the gentleness of the contact feel when it comes into contact with the oral cavity. This ensures that the gentleness of the contact feel when it comes into contact with the oral cavity can be maintained even if the hardness of the soft resin portion 23 is increased to improve the massage effect on the oral cavity. Furthermore, since the shaft 23A of the soft resin part 23 has a shape in which the diameter decreases from the base 23a side to the tip side, when a load is applied during brushing, the tip side including the constricted part 23C of the shaft 23A is more likely to bend than the base end side of the shaft 23A, thereby further improving the gentleness of contact with the oral cavity. Furthermore, between shaft 23A and expanded portion 23B at the tip, there is a constricted portion 23C whose diameter is smaller than that of the thickest portion 23b of expanded portion 23B. By providing such constricted portion 23C on the tip side (the base side of expanded portion 23B), flexibility is obtained at the tip side of constricted portion 23C even in a shape where the tip side is expanded in order to improve the feel of the tip against the oral cavity, so that both a massage effect and a gentle feel can be achieved in the oral cavity. In particular, when a load is applied to expanded portion 23B during brushing, the tip side of shaft 23A, including constricted portion 23C, is more likely to bend than the base end side of shaft 23A. However, when an excessive load is applied, constricted portion 23C actively bends, thereby preventing a decrease in the gentle feel, and further improving both a massage effect and a gentle feel in the oral cavity. Furthermore, since the cross-sectional shape of at least one of the base 23a and the constricted portion 23C is circular or approximately circular, the bending direction is not restricted to a specific direction when excessive load is applied, thereby further improving both the massage effect on the oral cavity and the gentle feel.

[0053] <Example> The effects of the present invention will be made clearer by the following examples. The present invention is not limited to the following examples, and can be practiced with appropriate modifications within the scope of the present invention.

[0054] (Block details) As shown in FIG. 3, the block 22 has a plurality of soft resin portions 23 and a base portion 24 that connects the base portions 23a of the plurality of soft resin portions 23 together.

[0055] (Total height H of the soft resin portion 23) As shown in Fig. 5, the overall height H of the soft resin portion 23 in the normal direction to the front surface 4a of the head portion 4 is preferably within a range of 8.0 mm to 15.0 mm, more preferably 8.0 mm to 12.0 mm, and even more preferably 9.0 mm to 11.0 mm. In the above embodiment, it is 10.0 mm. By setting the overall height H of the soft resin portion 23 within the above range, the entire soft resin portion 23 bends appropriately during brushing, and a sufficient load is applied when it comes into contact with the gums, thereby achieving both a comfortable feel in the oral cavity and a massaging effect. On the other hand, if the overall height H of the soft resin portion 23 is less than 8.0 mm or exceeds 15.0 mm, the balance of the flexure with the brush portion 21 will be lost, making it difficult to achieve a comfortable feel and massage effect in the oral cavity.

[0056] (Height H1 of shaft 23A) The height H1 of the shaft 23A of the soft resin portion 23 corresponds to the height from the surface 24a of the base 24 to the boundary P, and is preferably in the range of 4.0 mm to 11.0 mm, more preferably 6.0 mm to 10.0 mm, and even more preferably 7.0 mm to 9.0 mm. In the above embodiment, it is 8.0 mm. By setting the height H1 of the shaft 23A within the above range, a good balance of deflection with the brush portion 21 is achieved, making it difficult to obtain a comfortable contact feeling and massage effect in the oral cavity. On the other hand, if the height H1 of the shaft portion 23A is less than 4.0 mm or exceeds 11.0 mm, the balance of the flexure with the brush portion 21 will be lost, making it difficult to achieve a comfortable feel and massage effect in the oral cavity. The boundary P is defined based on the direction of the head portion 4 as viewed from the side.

[0057] (Height H2 of the expanded portion 23B) 5, the height H2 of the expanded portion 23B of the soft resin portion 23 corresponds to the length from the boundary P to the tip of the expanded portion 23B, and is preferably in the range of 1.3 mm to 4.5 mm, more preferably 1.5 mm to 4.0 mm, and even more preferably 1.5 mm to 3.5 mm. In the above embodiment, it is 2.3 mm. In this embodiment, it is preferable that the height H1 of the shaft portion 23A of the soft resin portion 23 is greater than the height H2 of the expanded portion 23B, and that the relationship H1>H2 is satisfied.

[0058] (Maximum shaft width D1 of base 23a) In the soft resin portion 23, the diameter of the shaft portion 23A is reduced from the base portion 23a toward the tip end, and the base portion 23a is the thickest. The maximum shaft width D1 of the base 23a of the shaft 23A is preferably in the range of 1.0 mm to 4.0 mm, more preferably 1.0 mm to 3.0 mm, and even more preferably 1.5 mm to 3.0 mm. In the above embodiment, it is 2.1 mm. D1 is the maximum width of base 23a of shaft 23A when soft resin portion 23 is viewed from the side or front. If the cross-sectional shape of shaft 23A is circular, D1 is its diameter. If the cross-sectional shape of shaft 23A is approximately circular, D1 is the maximum diameter. If the cross-sectional shape of shaft 23A is polygonal, D1 is the diameter of the circumscribed circle. Note that if the cross-sectional shape of shaft 23A is a polygon with a recess, D1 is the maximum width of the cross-sectional shape. By keeping the thickness within the above range, shaft 23A can have a suitable flexibility and feel good when it contacts the oral cavity. Furthermore, if shaft 23A has a shape in which the diameter decreases from base 23a to the tip, it becomes more likely to bend under the load during brushing, ensuring a gentle contact feeling in the oral cavity. On the other hand, if it is less than 1.0 mm, shaft 23A will bend too much on the side of base 23a, making it difficult to achieve a massaging effect inside the oral cavity.On the other hand, if it exceeds 4.0 mm, shaft 23A will lose flexibility on the side of base 23a, and the feeling of contact with the oral cavity may decrease.

[0059] (Minimum shaft width D2 of constricted portion 23C) In this embodiment, the minimum axial width of the constricted portion 23C is D2 shown in Fig. 5. That is, the minimum axial width D2 of the narrowest part of the soft resin portion 23 at the constricted portion 23C (hereinafter referred to as the narrowest part) is preferably in the range of 0.8 mm to 3.0 mm, more preferably 0.8 mm to 2.0 mm, and even more preferably 0.8 mm to 1.5 mm. In the above embodiment, it is 1.2 mm. D2 is the minimum width of constricted portion 23C when soft resin portion 23 is viewed from the side or front. If constricted portion 23C has a circular cross-sectional shape, D2 is its diameter. If constricted portion 23C has a substantially circular cross-sectional shape, D2 is its maximum diameter. If constricted portion 23C has a polygonal cross-sectional shape, D2 is the diameter of the circumscribed circle. Note that if constricted portion 23C has a polygonal cross-sectional shape with a recess, D2 is the maximum width of the cross-sectional shape. By setting the thickness within the above range, molding becomes easier, and the boundary P bends appropriately, improving the gentleness of the feel when it contacts the oral cavity. On the other hand, if it is less than 0.8 mm, molding becomes difficult, and if it exceeds 3.0 mm, flexibility at the boundary P decreases, making it difficult to bend.

[0060] (Maximum shaft width D3 of the expanded portion 23B) In this embodiment, the maximum axial width D3 of the expanded portion 23B is D3. That is, the maximum axial width D3 of the thickest part of the soft resin portion 23 in the expanded portion 23B (hereinafter referred to as the thickest part 23b) is preferably in the range of 1.0 mm to 4.0 mm, more preferably 1.0 mm to 3.5 mm, and even more preferably 1.0 mm to 3.0 mm. In the above embodiment, it is 2.0 mm. D3 is the maximum width of expanded portion 23B when viewed from the side or front. If the cross-sectional shape of expanded portion 23B is circular, D3 is its diameter. If the cross-sectional shape of expanded portion 23B is approximately circular, D3 is its maximum diameter. If the cross-sectional shape of expanded portion 23B is polygonal, D3 is the diameter of the circumscribed circle. Note that if the cross-sectional shape of expanded portion 23B is a polygon with a recess, D3 is the maximum width of the cross-sectional shape. By setting the thickness within the above range, the surface area of ​​the enlarged portion 23B is increased, and the contact area with the gums is increased, thereby enhancing the massage effect. On the other hand, if it is less than 1.0 mm, it is difficult to obtain a massaging effect in the oral cavity, and if it exceeds 4.0 mm, the balance of the degree of bending with the brush part 21 may be lost, which may reduce the comfort of contact with the oral cavity.

[0061] In a direction intersecting the center line O of the soft resin portion 23, when the cross-sectional area of ​​the base of the shaft portion 23A is X and the maximum cross-sectional area of ​​the thickest part 23b of the expanded portion 23B is Z, the value of Z / X is preferably in the range of 0.25 to 2.0, more preferably 0.5 to 2.0, and even more preferably 0.5 to 1.5. In other words, it is preferable that the maximum cross-sectional area Z is 0.25 to 2.0 times the base cross-sectional area X. In the embodiment described above, the diameter of base 23a is 2.1 mm, the diameter of thickest part 23b is 2.0 mm, and the thickness of thickest part 23b of expanded part 23B is approximately equal to the thickness of base 23a. By using such a shape, it is possible to transmit the stiffness of base 23a to the tip, and a sufficient massaging effect can be obtained inside the oral cavity.

[0062] In a direction intersecting the center line O of the soft resin portion 23, when the cross-sectional area of ​​the base of the shaft portion 23A is X and the cross-sectional area of ​​the narrowest part at the narrowest part (boundary P: minimum shaft width) of the constricted portion 23C is Y, it is preferable that the value of Y / X is in the range of 0.2 to 0.75, more preferably 0.4 to 0.7, and even more preferably 0.5 to 0.7. That is, it is preferable that the cross-sectional area Y of the narrowest part be 0.2 to 0.75 times the cross-sectional area X of the base part. In the above-described embodiment, the diameter of the base part 23a is 2.1 mm, and the diameter of the narrowest part (minimum axial width) is 1.2 mm, so that the narrowest part (boundary P) is thinner than the base part 23a. By adopting such a shape, the stiffness of the base part 23a can be reduced, improving the gentleness of the feel when it contacts the oral cavity.

[0063] In this way, by setting the relationship between the base cross-sectional area X, the narrowest part cross-sectional area Y, and the maximum cross-sectional area Z of the soft resin portion 23 within the above range, it is possible to achieve both a massaging effect on the oral cavity and a gentle feel on the oral cavity.

[0064] As shown in FIG. 3, the soft resin portions 23 are arranged at equal intervals along the length of the head portion 4. 4, the minimum distance d3 between the expanded portions 23B of adjacent soft resin portions 23 is preferably within a range of 0.5 mm to 2.0 mm, more preferably 0.5 mm to 1.7 mm, and even more preferably 0.7 mm to 1.5 mm. In the above embodiment, it is 1.1 mm.

[0065] The maximum distance d2 between the thinnest parts (boundary P) of adjacent soft resin portions 23 is preferably within a range of 1.0 mm to 5.2 mm, more preferably 1.0 mm to 3.0 mm, and even more preferably 1.5 mm to 2.3 mm.

[0066] The minimum distance d1 between the bases 23a of adjacent soft resin portions 23 is preferably within a range of 0.5 mm to 2.0 mm, more preferably 0.8 mm to 1.6 mm, and even more preferably 0.6 mm to 1.4 mm. In the above embodiment, it is 1.0 mm.

[0067] By keeping the minimum distance d1 between the expansion portions 23B of adjacent soft resin portions 23 and the minimum distance d3 between the base portions 23a within the above range, the expansion portions 23B of adjacent soft resin portions 23 are less likely to come into contact with each other, preventing a decrease in the comfort of contact in the oral cavity.

[0068] As shown in Fig. 4, the head portion 4 of the above embodiment has a pair of blocks 22. The sum (total width) of the widths W2 of the base portions 24 of the pair of blocks 22 relative to the overall width W1 (e.g., 15 mm) of the head portion 4 is preferably within a range of 10.0% to 55.0%, more preferably 15.0% to 45.0%, and even more preferably 20.0% to 35.0%. In the above embodiment, the width of each base portion 24 is approximately 2 mm, so the sum (total width) of the widths W2 of the base portions 24 relative to the overall width W1 of the head portion 4 is approximately 27%. By setting the sum (total width) of the widths W2 of the pair of bases 24 relative to the overall width W1 of the head 4 within the above range, a sufficient load can be applied when contacting the oral cavity during brushing, thereby achieving a sufficient massaging effect inside the oral cavity. In addition, two rows of soft resin, one on each side, come into contact with the gums, distributing the load on the gums and improving the comfort of contact.

[0069] Although the head unit 4 in the above embodiment has a pair of blocks 22, the number of blocks 22 is not limited to two. For example, a total of four blocks 22 may be provided in two rows on each side.

[0070] When the length L1 of the head portion 4 (hereinafter referred to as the head length) is within the range of 20.0 mm or more and 30.0 mm or less, the length L2 of the base portion 24 relative to the head length L1 is preferably within the range of 10% or more and 91% or less, more preferably 25.0% or more and 75.0% or less, and even more preferably 40.0% or more and 55.0% or less. In the above embodiment, the length L2 of the base portion 24 is approximately 12.0 mm. The minimum length L2 of the base portion 24 is 3.0 mm. The length L1 of the head portion 4 is the end point of the curve that forms the corner cutting from the neck portion 5 in the planar shape of the head portion 4, i.e., the position where the bending direction of the curve that forms the corner cutting changes. In other words, the boundary between the head portion 4 and the neck portion 5 is the position where the curve or straight line that forms both edges where the width of the corner cutting part of the head portion 4 from the neck portion 5 in the planar view changes from a curve or straight line that widens the width, or a straight line with the same width.

[0071] The sum of the maximum cross-sectional areas of the thickest parts 23b in each expanded part 23B of the soft resin parts 23 in the head part 4 is preferably in the range of 10.0% to 70.0% of the total area of ​​the base parts 24 in the head part 4, more preferably 30.0% to 65.0%, and even more preferably 40.0% to 60.0%. In the above embodiment, it is 51.0%.

[0072] The sum of the maximum cross-sectional areas of the narrowest parts (boundaries P) of each of the constricted portions 23C of the soft resin portions 23 in the head portion 4 is preferably within a range of 9.5% to 40.0%, more preferably 9.5% to 30.0%, and even more preferably 9.5% to 25.0%, relative to the total area of ​​the base portions 24 in the head portion 4. In the above embodiment, it is 18.4%. At least, by having the sum of the maximum cross-sectional areas of the thickest part 23b relative to the sum of the areas of the base part 24 within the above range, the soft resin part 23 bends appropriately when brushing, and when it comes into contact with the gums, a sufficient load is applied, making it possible to achieve both a massage effect on the oral cavity and a comfortable feel.

[0073] As shown in Figure 4, the head part 4 has, on the front surface 4a side, a bristle implantation area (first area) A1 where a plurality of bristle bundles 21a are implanted, and a pair of soft resin areas (second areas) A2 where blocks 22 are arranged. The bristle implantation area A1 is an area surrounding the outermost bristle bundles 21a by connecting them at the shortest distance. The brush part formation area A where the brush part 2 is formed is an area combining the bristle implantation area A1 and the pair of soft resin areas A2.

[0074] The ratio of the bristle implantation area A1 to the brush part formation area A is preferably within the range of 45.0% to 90.0%, more preferably 50.0% to 80.0%, and even more preferably 50.0% to 70.0%. The ratio of the pair of soft resin regions A2 to the brush portion forming region A is preferably within the range of 5.0% to 70.0%, more preferably 10.0% to 50.0%, and even more preferably 10.0% to 35.0%. In the head portion 4, by setting the ratio of the bristle implantation area A1 and the multiple soft resin areas A2 to the brush portion forming area A within the above ranges, the cleaning effect of the multiple bristle bundles 21a can be sufficiently obtained, and the multiple soft resin parts 23 can be made to feel gentle when they contact the oral cavity. It is preferable that the bristle-implanted area A1 is larger than the total area of ​​the soft resin area A2 in the head portion 4. By making the bristle-implanted area A1 sufficiently large relative to the soft resin area A2, it is possible to achieve both a good cleaning effect and a comfortable feel.

[0075] In the above-described embodiment, the tip end of the soft resin portion 23 is not branched, but it may be branched into multiple parts. For example, up to 15 branches are possible for the same base portion 23a. If there are more than 15 branches, it becomes difficult to obtain a massage effect.

[0076] The density range of the bristles used in the bristles implantation area A1 is preferably in the range of 3.0 strands / mm2 or more and 350 strands / mm2 or less, more preferably 3.0 strands / mm2 or more and 200 strands / mm2 or less, and even more preferably 5.0 strands / mm2 or more and 100 strands / mm2 or less.

[0077] The density range of the soft resin portion 23 relative to the total area of ​​the base portion (the pair of soft resin regions A2) is as follows. The density range of the soft resin portion 23 is preferably in the range of 0.05 pieces / mm2 or more and 1.90 pieces / mm2 or less, more preferably 0.05 pieces / mm2 or more and 1.00 pieces / mm2 or less, and even more preferably 0.10 pieces / mm2 or more and 0.50 pieces / mm2 or less.

[0078] By setting the ratio of the density of the soft resin portion 23 to the density of the bristles within the above range, the density of the bristle bundles 21a is greater than the density of the soft resin portion in the head portion 4, thereby ensuring a sufficient number of bristle bundles in the brush portion 21. This ensures a cleaning effect within the oral cavity while enhancing the massaging effect and gentle feel within the oral cavity. The thickness of the bristles constituting the bristle bundles 21a is within the range of 4 mils to 9 mils.

[0079] In the entire head portion 4, the sum of the thickest parts 23b in the multiple soft resin parts 23 relative to the hair implantation area A1 is preferably in the range of 3.5% or more and 60.0% or less, more preferably 5.0% or more and 40.0% or less, and even more preferably 10.0% or more and 30.0% or less.

[0080] Furthermore, throughout the entire head portion 4, it is preferable that the sum of the thinnest parts 23c of the multiple soft resin parts 23 relative to the hair implantation area A1 is in the range of 2.0% or more and 35.0% or less, more preferably 2.0% or more and 20.0% or less, and even more preferably 2.0% or more and 10.0% or less.

[0081] By keeping the ratio of the thickest part 23b and the thinnest part 23c to the bristle implantation area A1 within the above range, the bristle implantation area A1 can be sufficiently secured, thereby obtaining both the cleaning effect of the multiple bristle bundles 21a and the massage effect of the soft resin part 23.

[0082] Although the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to the above-described examples. The shapes and combinations of the components shown in the above-described examples are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0083] Second Embodiment The configuration of a toothbrush according to one aspect of the present invention will be described below with reference to FIGS. The following embodiment shows one aspect of the present invention, does not limit the present invention, and can be modified as desired within the scope of the technical concept of the present invention. In addition, in the following drawings, the scale and number of each structure are different from the actual structure to make each configuration easier to understand.

[0084] <Toothbrush> The toothbrush 100 of this embodiment has a brush portion 103, a head portion 123 having the brush portion 103 on the bristle surface 123a, a neck portion 122 extending longitudinally from the rear end of the head portion 123, and a handle portion 121 extending longitudinally from the rear end of the neck portion 122 to the opposite side of the head portion 123, and has an elongated shape with a length in the axial direction. As shown in Figures 7 to 9, the toothbrush 100 of this embodiment comprises a toothbrush body (first resin) 102 made of hard resin, a pair of soft resin parts (second resin) 105 made of soft resin, and a bristle part 104 consisting of multiple bristle bundles 104a.

[0085] (Toothbrush body) As shown in Figures 7 to 9, the toothbrush body 102 is made of a hard resin as a first resin, and has a head component (first resin part) 123A that forms part of the head part 123, a neck component 122A that forms the neck part 122, and a handle component 121A that forms part of the handle part 121.

[0086] The first resin constituting the toothbrush body 102 may be a hard or soft resin. Examples of hard resins include polypropylene (PP), polyacetal (POM), polycyclohexylene dimethylene terephthalate (PCT), polyethylene terephthalate (PET), polycarbonate (PC), acrylonitrile-butadiene-styrene resin (ABS), polymethyl methacrylate (PMMA), polystyrene (PS), acrylonitrile-butadiene-styrene resin (ABS), cellulose propionate (CP), and polyarylate. Biodegradable resins, plant-derived resins, paper-blended resins, plant-blended resins, and the like may also be used. Among these, PP is preferred due to its excellent moldability and cost advantages.

[0087] Examples of soft resins include polyolefin-based thermoplastic elastomers, polystyrene-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, polyester-based thermoplastic elastomers, 1,2-polybutadiene-based thermoplastic elastomers, ethylene-vinyl acetate-based thermoplastic elastomers, polyvinyl chloride-based thermoplastic elastomers, natural rubber-based thermoplastic elastomers, fluorine-based thermoplastic elastomers, and trans-polyisoprene-based thermoplastic elastomers.

[0088] Of toothbrush body 102, head constituent part 123A, together with elastomer bases 152 of a pair of soft resin parts (second resin parts) 105 (described later), constitutes head part 123 of toothbrush 100. In addition, handle constituent part 121A, together with grip part 121B, constitutes handle part 121.

[0089] The head constituent part 123A has a hard resin part 230 located in the center, and a pair of soft resin containing parts (second resin parts) 123B formed on both sides of the hard resin part 230 in the width direction. The pair of soft resin accommodating sections 123B are grooves that penetrate the thickness direction of the head constituent section 123A at the side edge positions of the head section 123, and are grooves that open to the bristle-implanted surface 123a and the back surface 123d of the head section 123, as well as to the outer circumferential surface 123c. The shape of the pair of soft resin accommodating sections 123B when viewed from the front (bristle-implanted surface 123a) side and when viewed from the side are both rectangular. The pair of soft resin accommodating sections 123B are located approximately in the center of the head constituent section 123A in the longitudinal direction.

[0090] As shown in Figures 10B, 14, and 15, the head constituent part 123A has a pair of hard-resin-side fixing parts 123g that protrude into the pair of soft-resin containing parts 123B. The pair of hard-resin-side fixing parts 123g are convex parts that are perpendicular to the wall surfaces on both sides in the length direction of each soft-resin containing part 123B. The pair of hard-resin-side fixing parts 123g are located approximately in the center in the thickness direction of the head constituent part 123A and are spaced apart from both the bristle-implanted surface 123a and the back surface 123d. In this embodiment, the pair of hard-resin-side fixing parts 123g are formed in a position slightly closer to the bristle-implanted surface 123a than the back surface 123d.

[0091] As shown in FIGS. 15 and 16, each of the hard resin side fixing portions 123g has a substantially square shape when viewed from the front, but the shape in plan view is not limited to this and can be changed as appropriate. When viewed from the flocking surface 123a, one side 123g1 of each hard resin side fixing portion 123g coincides with the outer peripheral surfaces 123c on both widthwise sides of the head portion 123, and is spaced outward in the widthwise direction from the side surfaces 123b of the head constituent portion 123A. That is, there is a gap S (FIG. 10A) between each hard resin side fixing portion 123g and each side surface 123b of the head constituent portion 123A.

[0092] 4, a first locking portion 123h is locked to the center of each hard resin side fixing portion 123g in a front view. In this embodiment, the first locking portion 123h is a through hole that penetrates the hard resin side fixing portion 123g in the thickness direction. The size and shape of the through hole in a plan view can be changed as appropriate.

[0093] The head component 123A has a plurality of tufting holes 124 formed in the tufting surface 123a. In this embodiment, two tufting hole rows 124N are formed in the width direction of the head component 123A. Each tufting hole row 124N is made up of a plurality of tufting holes 124 aligned in the length direction of the head component 123A, and in this embodiment, each tufting hole row 124N has eight tufting holes 124.

[0094] The number of tufting hole rows 124N formed in the head component 123A, the number of tufting holes 124 constituting each tufting hole row 124N, and the diameter of each tufting hole 124 can be changed as appropriate depending on the size of the head component 123. The diameter of the tufting holes 124 is preferably 1.5 mm or more and 3.0 mm or less, and more preferably 2.0 mm or more and 2.5 mm or less.

[0095] (hair bundle) In this embodiment, bristle bundles 104a consisting of multiple bristles are implanted in each bristle implantation hole 124 formed in the head component 123A using a flat line or the like. The bristles that make up the bristle bundles 104a include straight bristles, bristles whose diameter gradually decreases toward the tip (tapered bristles), bristles with branched ends, spiral bristles, and bristles with irregular cross sections. The tip shapes of the bristle bundles 104a include flat cut, mountain cut, convex, and concave shapes. They may also have an offset shape with a step between half bristle bundles separated by a flat line. The type of bristles used and the tip shape of the bristle bundles 104a are appropriately determined taking into consideration the cleaning effect desired for the brush part 104 and the feel against the gums. The toothbrush is not limited to the implanted bristles as described above, and may be an integrally molded toothbrush in which the bristles are molded by two-color molding or insert molding.

[0096] (A pair of soft resin parts) As shown in Figures 7 to 12, a pair of soft resin parts 105 are housed in soft resin housing parts 123B formed on both widthwise sides of the head component 123A, and both longitudinal sides of each soft resin part 105 are connected to the head component 123A, thereby forming them integrally with the toothbrush body 102.

[0097] These pairs of soft resin portions 105 are located within each soft resin accommodating portion 123B, away from the outer sides 123b of the centrally located hard resin portion 230 in the width direction, and face each side 123b of the hard resin portion 230 with a gap S therebetween.

[0098] The gap S between the soft resin portion 105 and the side surface 123b of the hard resin portion 230 is approximately the same as the gap formed between the hard resin side fixing portion 123g in the head component 123A described above and each side surface 123b of the head component 123A.

[0099] Each soft resin portion 105 is made of soft resin, and has a plurality of elastomer portions 151, an elastomer base 152, and a pair of second locking portions 153, as shown in FIGS. 10B and 11.

[0100] The hardness of the soft resin portion 105 is preferably within a range of Shore A hardness of 20 to 60. In this embodiment, the Shore A hardness is 30, for example.

[0101] Examples of the soft resin that constitutes the soft resin portion 105 include polyolefin-based thermoplastic elastomers, polystyrene-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, polyester-based thermoplastic elastomers, 1,2-polybutadiene-based thermoplastic elastomers, ethylene-vinyl acetate-based thermoplastic elastomers, polyvinyl chloride-based thermoplastic elastomers, natural rubber-based thermoplastic elastomers, fluorine-based thermoplastic elastomers, and trans-polyisoprene-based thermoplastic elastomers.

[0102] The multiple elastomer portions 151 extend vertically from the surface (front surface) 152a of the elastomer base 152. In this embodiment, as shown in FIG. 10A, there are five elastomer portions 151 on each side. The number of elastomer portions 151 provided on one side is preferably three to seven, and more preferably three to five. To obtain a massaging effect on the gums, it is preferable that the number of elastomer portions 151 is at least three.

[0103] In this embodiment, as shown in FIG. 10B, each elastomer portion 151 has a cylindrical shape or a tapered shape that narrows toward the tip. The shape of the elastomer portion 151 is not limited to the above-described shape and can be modified as appropriate. In this embodiment, all of the multiple elastomer portions 151 have the same shape, but multiple elastomer portions 151 with different shapes may be provided. The tip of the elastomer portion 151 is preferably shaped in consideration of the comfort of contact with the gums, and in this embodiment, it is hemispherical.

[0104] In this embodiment, the five elastomer portions 151 are formed at equal intervals in the longitudinal direction of the elastomer base 152. The base ends of the elastomer portions 151 are connected to each other by the elastomer base 152, and the tip ends are independent of each other.

[0105] It is preferable that the multiple elastomer portions 151 are formed at positions excluding the end portions 152c on both sides in the longitudinal direction of the elastomer base 152. Furthermore, of the five elastomer portions 151 arranged in a row, at least three elastomer portions 151 at the center in the arrangement direction are located at the center in the longitudinal direction of the elastomer base 152 (soft resin containing portion 123B) (movable portion 152f described later).

[0106] In this embodiment, the plurality of elastomer portions 151 are arranged in a line in the length direction of the head portion 123, but a configuration in which a plurality of rows (two rows) are provided in the width direction may also be used.

[0107] 10B, the height H from the base end (the surface of the elastomer base 152) to the tip end of each of the elastomer parts 151 is equal to one another. The height H of each of the elastomer parts 151 is shorter than the length of the bristle bundles 104a, and it is preferable that the difference in length between the elastomer parts 151 and the bristle bundles 104a is about 1 mm.

[0108] As shown in Fig. 10A, the elastomer base 152 has a rectangular shape in a plan view, and substantially matches the planar shape of the soft resin housing portion 123B described above. One surface 152a in the thickness direction of the elastomer base 152 matches the bristle-implanted surface 123a of the head component 123A. Ends 152c on both ends in the length direction of the elastomer base 152 are connected to the head component 123A. As shown in Figs. 10B and 12, the elastomer base 152 has a movable portion 152f, at least the central portion in the length direction of which is thin-walled.

[0109] The movable portion 152f is separated from the head forming portion 123A and is a portion that can move in the thickness direction and width direction of the elastomer base 152. At least three of the five elastomer portions 151 described above are present in the movable portion 152f. The length L2 (FIG. 10B) of the movable portion 152f in the longitudinal direction of the elastomer base 152 is preferably a length that allows for the arrangement of at least three of the elastomer portions 151 described above, and is preferably 10 mm or more and 28 mm or less, and more preferably 15 mm or more and 25 mm or less.

[0110] 10B and 12, thickness T2 of at least movable portion 152f of elastomer base 152 is formed thinner than thickness T1 of head constituent portion 123A. Within soft resin containing portion 123B, space K exists on the rear surface 152d side of movable portion 152f. Because space K exists on the rear surface side of elastomer base 152, when movable portion 152f is deflected toward rear surface 123d of head portion 123 due to the load during brushing, there is nothing to hinder its movement, and an effect of sinking in the thickness direction of head portion 123 is obtained.

[0111] The pair of second locking portions 153 are for connecting each end 152c of the elastomer base 152 to the hard resin side fixing portion 123g of the head constituent portion 123A, and are formed on the back surface side of each end 152c on both sides in the longitudinal direction of the elastomer base 152. The pair of second locking portions 153 have a soft resin side fixing portion 153A and a connecting portion 153h.

[0112] The pair of second locking portions 153 extend vertically from the back surface 152d of the elastomer base 152 along the end surface 231 of the hard resin side fixing portion 123g and extend parallel to the elastomer base 52 along the back surface 232 of the hard resin side fixing portion 123g, forming a generally L-shape in the side view shown in FIG. 10B. Of the second locking portions 153, the first portion 153a covers the end surface 231 of the hard resin side fixing portion 123g, and the second portion 153b covers the back surface 232 of the hard resin side fixing portion 123g. In the thickness direction of the head portion 123, the second portion 153b of the second locking portion 153 faces the end portion 152c of the elastomer base 152, with the hard resin side fixing portion 123g interposed therebetween.

[0113] Connection portion 153h is formed in first locking portion 123h (through hole) of hard-resin-side fixing portion 123g, and connects second portion 153b of soft-resin-side fixing portion 153A to end portion 152c of elastomer base 152. In this way, a part of second locking portion 153 on the soft-resin portion 105 side is locked with first locking portion 123h (hard-resin-side fixing portion 123g), and thereby, pair of soft-resin portions 105 are fixed to toothbrush body 102 while being arranged in soft-resin accommodation portion 123B.

[0114] In this manner, the toothbrush 100 is constructed. In this embodiment, when a pair of soft resin parts 105 are attached to toothbrush body 102, as shown in Fig. 10A, the soft resin parts arranged in soft resin accommodation parts 123B on both sides in the width direction are spaced outward in the width direction from the respective side surfaces 123b of head constituent part 123A, with a gap S formed between them. This gap S allows soft resin part 105 (movable part 152f) to deform in the width direction, and a massaging effect on the gums can be obtained without elastomer part 151 interfering with the movement of bristle bundles 104a.

[0115] In addition, the gap S allows the movable part 152f in the soft resin part 105 to sink in a twisting manner when it bends in the thickness direction, and the continuous elasticity obtained by the complex movement (twisting behavior) of the elastomer part 151 further enhances the massage effect on the gums.

[0116] 10B, in the thickness direction of head portion 123 within pair of soft resin containing portions 123B, a space K is formed on the rear surface 152d side of elastomer base 152. This space K allows movable portion 152f in soft resin portion 105 to move in the thickness direction, and allows head portion 123 to deform toward rear surface 123d due to the load applied when brushing, making it possible to massage the gums with an appropriate (constant) load.

[0117] In this embodiment, the bristle bundles 104a and the elastomer part 151 each move differently, and therefore each provides different functions, resulting in a toothbrush 100 that combines the cleaning effect on the tooth surface and cervical area provided by the bristle bundles 104a with the massaging effect on the gums provided by the elastomer part 151.

[0118] When a load of 200 g is applied to elastomer portion 151 during brushing, it displaces together with elastomer base 152 by 1.0 mm or more and 2.0 mm or less in the thickness direction of head portion 123. This behavior of elastomer portion 151 allows a constant load to be applied to the gums during brushing. [Example]

[0119] The present invention will be described in more detail below by showing examples, but the present invention is not limited to the following description.

[0120] <Dimensions of head portion 123> As shown in Figures 7 and 8, the length L1 of the head portion 123 is preferably within a range of 20 mm or more and 35 mm or less. Here, the length L1 of the head portion 123 refers to the length from the tip of the head portion 123 to the boundary between the head portion 123 and the neck portion 122. The boundary between the head portion 123 and the neck portion 122 is the end point of the curve that forms the corner cutting from the neck portion 122 in a planar view of the head portion 123, that is, the position where the bending direction of the curve that forms the corner cutting changes. In other words, the boundary between the head portion 123 and the neck portion 122 is the position where the curve or straight line that forms both edges where the width of the corner cutting portion of the head portion 123 from the neck portion 122 in a planar view changes from a curve or straight line that forms an increasing width, or a straight line with the same width.

[0121] 12, the thickness T1 of the head portion 123 is preferably 2.6 mm or more and 7.0 mm or less, and more preferably 2.6 mm or more and 5 mm or less. Here, the thickness of the head portion 123 refers to the length from the implanted surface 123a to the back surface 123d.

[0122] 10A and 11, the overall width W1 of the head portion 123 is preferably 8.0 mm or more and 15 mm or less, and more preferably 8.0 mm or more and 13 mm or less. Here, the overall width W1 of the head portion 123 refers to the total length of the hard resin width W2 (the distance between the side surfaces 123b of the head constituent portion 123A), the total width W3 of the multiple soft resin portions 105, and the total width Ws of the multiple gaps S described below. The hard resin width W2 is preferably 3.0 mm or more and 8.0 mm or less, and more preferably 5.0 mm or more and 7.0 mm or less.

[0123] The diameter of the tufting hole 124 is preferably 1.5 mm or more and 3.0 mm or less, and more preferably 2.0 mm or more and 2.5 mm or less. The number of tufting holes 124 in the width direction is preferably 2 to 6, and more preferably 2 to 4. The number in the longitudinal direction is preferably 2 to 12, and more preferably 2 to 10. The total number of tufting holes 124 is preferably 6 to 30.

[0124] As shown in FIG. 11, the size of the gap S, that is, the width Ws of the gap S, is preferably in the range of 0.0 mm or more and 3.7 mm or less, and more preferably 0.0 mm or more and 2.0 mm or less.

[0125] <Dimensions of the soft resin portion 105> (Width direction of the soft resin portion 105) Here, the width of the soft resin portion 105 is defined as the width dimension of the movable portion 152f of the elastomer base 152. The width W3 of each soft resin portion 105 (movable portion 152f) is preferably within a range of 1.5 mm to 3.3 mm, and more preferably 2.0 mm to 2.5 mm. By keeping the width within the above range, a massaging effect on the gums can be obtained.

[0126] The total width W3 of the multiple soft resin portions 105 is preferably in the range of 10% to 70% of the overall width W1 of the head portion 123, and more preferably in the range of 30% to 65%. By setting the ratio of the soft resin portions 105 in the width direction of the head portion 123 within the above range, it is possible to ensure a massaging sensation on the gums.

[0127] (Thickness direction of the soft resin portion 105) Here, as shown in FIG. 12, the thickness dimension of the movable portion 152f of the elastomer base 152 is defined as the thickness T2 of the soft resin portion 105. The ratio of the thickness T2 of the movable portion 152f to the thickness T1 of the head portion 123 (head constituent portion 123A) is preferably 7% or more and 50% or less, and more preferably 20% or more and 30% or less. By setting the ratio of the thickness T2 of the movable portion 152f to the thickness T1 of the head portion 123 within the above range, it is possible to ensure a massage sensation with an appropriate load (200 g) due to distortion in the width direction.

[0128] The thickness T2 of the movable portion 152f in the soft resin portion 105 is preferably in the range of 0.5 mm to 5 mm, more preferably in the range of 0.5 mm to 2.5 mm, and even more preferably in the range of 0.5 mm to 1.5 mm. The molding limit for the thickness T2 of the movable portion 152f is 0.5 mm. If the thickness T2 exceeds 5.0 mm, the amount of deflection decreases, making it difficult to obtain an appropriate load on the gums. Therefore, by keeping the thickness within the above range, a massage effect can be obtained with an appropriate amount of deflection and an appropriate load.

[0129] (Length direction of the soft resin part 105) As shown in FIG. 8, the length L3 of the soft resin portion 105 (elastomer base 152) is preferably 20% or more of the length L1 of the head portion 123, more preferably 50% or more, and even more preferably 65% ​​or more. In the case where the elastomer base 152 of the soft resin portion 105 is configured to be divided in the length direction, the calculation is made using the total of the elastomer bases 152. By setting the length L3 of the soft resin portion 105 (the length of the elastomer base 152) relative to the length L1 of the head portion 123 within the above range, it is possible to ensure a minimum massaging sensation on the gums.

[0130] The length L3 of the soft resin part 105 (the length of the elastomer base 152) is preferably equal to or greater than the distance required to line up three elastomer parts 151. The length L3 of the movable part 152f in the soft resin part 105 is preferably equal to or greater than 10.0 mm and equal to or less than 28.0 mm, and more preferably equal to or greater than 15 mm and equal to or less than 25 mm.

[0131] The soft resin portion 105 may have a maximum length equal to the length L1 of the head portion 123. In the above embodiment, one soft resin portion 105 is provided on each side of the head portion 123, but multiple (two) soft resin portions 105 may be arranged in the length direction of the head portion 123.

[0132] (Height of elastomer part 151, height of bristle bundle 104a) The height H of the elastomer portion 151 (the height H of the elastomer portion 151 above the surface 152a of the elastomer base 152) is preferably in the range of 8.0 mm to 11.0 mm, and more preferably in the range of 10.0 mm to 11.0 mm. By setting it in this range, an appropriate massaging sensation can be obtained for the gums. The bristle length of the bristle bundle 104a is preferably within a range of 8.0 mm or more and 12.0 mm or less. The elastomer portion 151 preferably has a shorter bristle height than the bristle tufts 104a. The height difference (step) between bristle bundles 104a and elastomer portion 151 is preferably 0.0 mm or more and 2.0 mm or less, and more preferably 0.0 mm or more and 1.0 mm or less. When height H of elastomer portion 151 is shorter than the bristle length of bristle bundles 104a, a massaging sensation can be imparted to the gums without impeding the movement of bristle bundles 104a. Therefore, having a height difference within the above range makes it easier to obtain both a cleaning sensation for the cervical region of the teeth and a massaging sensation for the gums. The width of the base end of each elastomer portion 151 is preferably 1.5 mm to 3.3 mm, more preferably 2.0 mm to 2.5 mm, and even more preferably 2.2 mm to 2.4 mm. In this embodiment, it is 2.4 mm. The length of the elastomer portion 151 in the longitudinal direction on the base end side is preferably 1.5 mm to 3.3 mm, more preferably 2.0 mm to 2.5 mm, and even more preferably 2.2 mm to 2.4 mm. In this embodiment, it is 2.4 mm. The shortest distance between the elastomer portions 151, i.e., the shortest distance between adjacent elastomer portions 151 on the base end side, is preferably 0.1 mm to 3 mm, more preferably 0.2 mm to 2 mm, and even more preferably 0.4 mm to 1 mm. In this embodiment, it is 0.7 mm.

[0133] When the load during brushing is 200 g, the displacement of elastomer portion 151 (deflection in the thickness direction of elastomer base 152) is 1.0 mm to 2.0 mm, providing a suitable cleaning sensation and massage feeling.

[0134] (Soft resin width W3 and hard resin width W2 (proportion of the two)) The ratio of the total width of the soft resin portions 105 to the overall width (hereinafter referred to as the gap-free head width), which is the sum of the total width of the pair of soft resin portions 105 and the hard resin width W2, is preferably 20% to 80%, and more preferably 30% to 60%. By keeping it within the above range, it is possible to simultaneously obtain a cleaning feeling from the bristle bundles 104a and a massaging feeling from the elastomer portion 151. If the ratio of the total width of the soft resin portions 105 to the gap-free head width exceeds 80%, it is difficult to ensure the rigidity of the head portion 123, and if it is less than 20%, it is difficult to obtain a massaging feeling from the elastomer portion 151.

[0135] (Gap S width direction) The length obtained by subtracting the total width of the pair of gaps S from the overall width W1 of the head portion 123, i.e., the total length of the total width of the soft resin portions 105 (each with a width W3) and the hard resin width W2 of the head constituent portion 123A, preferably accounts for 60% or more, and more preferably 80% or more of the overall width W1 (width including the gaps S) of the head portion 123. This makes it possible to ensure a movable area in the width direction of the movable portion 152f of the soft resin portion 105.

[0136] It is also possible to employ a configuration in which there is no gap S. The combined length of the hard resin width W2 of the head constituent portion 123A and the pair of soft resin widths W3 may coincide with the overall width W1 of the head portion 123.

[0137] (Length direction of gap S) As shown in FIG. 10A, the length Ls of the gap S formed between the head component 123A (side surface 123b) and the soft resin portion 105 preferably coincides with the length L3 of the soft resin portion 105 and exists along 20% ​​or more of the length of the head portion 123.

[0138] In the above embodiment, the length Ls of the gap S (length L3 of the soft resin portion 105) relative to the length direction of the head portion 123 is preferably 20% or more, and more preferably 65% ​​or more. It is preferably 80% or less, and more preferably 70% or less. By setting the length Ls of the gap S within the above range, movement such as bending (twisting) in the width direction of the elastomer base 152 of the soft resin portion 105 is possible.

[0139] (Space K) A space K exists on the rear side of the elastomer base 152 . The size of the space K in the thickness direction of the head portion 123 is preferably within a range of 30% to 95% of the thickness of the head portion 123, and more preferably within a range of 45% to 80%. The size of the space K in the length direction of the head portion 123 is preferably 10% to 70% of the length L1 of the head portion 123, and more preferably 30% to 50%. The size of the space K in the width direction of the head portion 123 is preferably 20% to 80% of the overall width W1 of the head portion 123, and more preferably 40% to 70%. By setting the size of the space K within the above range, a movable area for the elastomer base 152 can be ensured.

[0140] The effects of the present invention will be more clearly understood from the following examples. Note that the present invention is not limited to the following examples and can be practiced with appropriate modifications within the scope of the present invention.

[0141] (Examples 1 to 22, Comparative Examples 1 and 2) In the present example, toothbrushes of Examples 1 to 22 and Comparative Examples 1 and 2 were prepared according to the specifications shown in Table 1 below, as samples similar to the toothbrushes shown in FIGS. The dimensions of each part of each example toothbrush are shown in Tables 1 to 4.

[0142] The basic configuration of each sample in Examples 1 to 22 corresponds to the toothbrush of the above-mentioned embodiment 1, and a pair of soft resin portions 105 are integrally molded with toothbrush body 102 made of hard resin.

[0143] In the sample of Comparative Example 1, the toothbrush body is formed from soft resin (two-color molding using soft resin material). In the sample of Comparative Example 2, a pair of soft resin portions are formed of hard resin (two-color molding using hard resin material). Note that 85R is a hardness notation in Rockwell hardness (R), and the Shore A hardness is over 60.

[0144] The common specifications for Examples 1 to 22 and Comparative Examples 1 and 2 are as follows. Thickness T1 of head portion 123 = (thickness of head component 123A): 5 mm Length L1 of head portion 123 = (from the tip of head portion 123 to the boundary between head portion 123 and neck portion 122): 30 mm Hair length of hair bundle 104a: 11mm Diameter of implantation hole 124: 2.0 mm (specifications of Figure 10A) Number of implantation holes 124: 2 holes in the width direction, 8 holes in the longitudinal direction (specifications of Figure 10A) Number of implantation holes 124: 16 holes (specifications of Figure 10A)

[0145] The specification items for the samples of Examples 1 to 22 and Comparative Examples 1 and 2 relate to the dimensions of the head portion 123, the soft resin portion 105, and the bristle bundle 104a, and were set for each sample.

[0146] (Head specifications) "Width W1 (mm) of head portion 123": Overall width W1 of head portion 123 (width of hard resin portion 230 + total width of soft resin portion + total width of gap S) "Thickness T1 (mm) of the head part 123": the length from the tufting surface 123a to the back surface 123d "Length L1 (mm) of head portion 123": length from the tip of head portion 123 to the boundary of neck portion 122 - "Width of hard resin part 230 W2 (mm)" "Total width of gap S (mm)"

[0147] (Soft resin part specifications) "Width (mm) of elastomer base 152 (movable part 152f)": Width of one elastomer base 152 = total width if there are multiple elastomer bases 152 on one side "Number of elastomer bases 152 in the width direction (per side / total)" "Thickness (mm) of elastomer base 152 (movable part 152f)" "Length (mm) of the elastomer base 152 in the longitudinal direction": if there are multiple elastomer bases 152 in the longitudinal direction, the total length - "Number of longitudinal elastomer bases 152": Only one side "Number of elastomer parts 151 in the longitudinal direction": Only on one side "Number of elastomer parts 151 in the width direction": Only on one side "Width of one base end of the elastomer portion 151 (mm)": Only one side "Length (mm) of one of the elastomer portions 151 in the longitudinal direction on the base end side": only on one side "The shortest distance between the base ends of adjacent elastomer portions 151 (mm)" "Height H (mm) of elastomer part 151" - "Shore A hardness of soft resin part 105 (elastomer part 151)"

[0148] (hair bundle) "Hair length of hair bundle 104a (mm)": Height from the hair implantation surface 123a to the tip

[0149] [Table 1]

[0150] [Table 2]

[0151] [Table 3]

[0152] [Table 4]

[0153] [Evaluation method] (Feels like the brush cleans the entire mouth) [Test method] Ten monitors cleaned the oral cavity with each of the toothbrushes of Examples 1 to 22 and Comparative Examples 1 and 2, and evaluated the "feeling of cleaning the entire mouth with the bristles" according to the following criteria. <Judgment criteria> If the average score of the 10 monitors was 4 points or more, it was marked with a "◎", if it was less than 4 points and 3 points or more, it was marked with a "〇", and if it was less than 3 points, it was marked with an "×". 5 points: "The brush part gives a very good feeling of cleaning the entire mouth." 4 points: "Feels like the brush cleans the whole mouth" is somewhat good. 3 points: I can't say for sure whether the brush really cleans the whole mouth. 2 points: "Feeling that the brush part cleans the whole mouth" is somewhat poor. 1 point: "Feeling that the brush part cleans the whole mouth" is very poor.

[0154] (Feels like a gentle massage from the elastomer part of the entire mouth) [Test method] Ten monitors cleaned the oral cavity with each of the toothbrushes of Examples 1 to 22 and Comparative Examples 1 and 2, and evaluated the "feeling of the massage of the entire mouth by the elastomer part" according to the following criteria. <Judgment criteria> If the average score of the 10 monitors was 4 points or more, it was marked with a "◎", if it was less than 4 points and 3 points or more, it was marked with a "〇", and if it was less than 3 points, it was marked with an "×". 5 points: "The elastomer part gives a great feeling of massaging the entire mouth." 4 points: "The elastomer part provides a massage feeling throughout the mouth" is somewhat good. 3 points: I can't really say whether the "elastomer part massages the entire mouth" is satisfactory or not. 2 points: The "feeling of the elastomer part massaging the entire mouth" is somewhat poor. 1 point: "The feeling of massaging the entire mouth with the elastomer part" is very poor.

[0155] As shown in Table 1, among Examples 1 to 22, the samples of Examples 1 to 4, 6, 11, 14, 15, 17, 19, and 22 were highly rated for the cleaning sensation (on the cervical region) with the brush part.

[0156] Furthermore, among Examples 1 to 22, the samples of Examples 1, 8, and 21 were highly rated for the massaging sensation (on the gums) provided by the elastomer portion.

[0157] From the above, among Examples 1 to 22, the sample of Example 1 was highly evaluated for both the cleaning sensation of the cervical region by the brush part 104 and the appropriate massaging sensation of the gums.

[0158] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to these examples. The shapes and combinations of the components shown in the above examples are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0159] For example, the fixing structure (mounting structure) of the soft resin part 105 to the head constituent part 123A is not limited to the structure described above, and other structures may be adopted. In the embodiment described above, the first locking parts 123h of the pair of hard-resin-side fixing parts 123g in the head constituent part 123A are formed as through-holes, and a part of the soft resin part 105 (the second locking part 153) is locked so as to be filled into this through-hole, thereby fixing the pair of soft resin parts 105 to the head constituent part 123A. However, the first locking parts 123h may not be through-holes, but may be grooves, recesses, or the like. Furthermore, the shape of the second locking portion 153 of the soft resin portion 105 is not limited to the above-mentioned shape, and may be changed as appropriate to match the shape of the first locking portion 123h side of the head forming portion 123A.

[0160] Furthermore, in the above embodiment, a space K exists on the back side of each soft resin part 105, but if the movable part 152f of the soft resin part 105 has good flexibility in the width direction and thickness direction, the space K may not be present.

[0161] (Third embodiment) The configuration of a toothbrush according to one aspect of the present invention will be described below with reference to FIGS. The following embodiment shows one aspect of the present invention, does not limit the present invention, and can be modified as desired within the scope of the technical concept of the present invention. In addition, in the following drawings, the scale and number of each structure are different from the actual structure to make each configuration easier to understand. In addition, in the description of the third embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

[0162] The toothbrush 300 of this embodiment has a configuration that combines the configurations of the first and second embodiments. Specifically, instead of the elastomer portion 151 in the toothbrush of the second embodiment, a configuration similar to the soft resin portion 23 of the first embodiment is adopted.

[0163] <Toothbrush> 19 and 20, toothbrush 300 of this embodiment has toothbrush body (first resin part) 102 made of hard resin (first resin), a pair of soft resin parts 305 made of soft resin (second resin), and bristle part 104 made of multiple bristle bundles 104a. Brush part 303 of this embodiment is composed of the pair of soft resin parts (second resin parts) 305 and brush part 104.

[0164] The soft resin portion 305 has a plurality of elastomer portions 23 and an elastomer base 152 that connects the base ends of the plurality of elastomer portions 23 together. The elastomer base 152 has the same configuration as in the second embodiment, with a pair of longitudinal ends of the head connected to the toothbrush body 102. As described above, the elastomer base 152 has a movable part 152f that is movable in the thickness and width directions of the elastomer base 152, separating from the toothbrush body 102. The gap S formed between the elastomer base 152 and the hard resin part 230 of the head 123 and the space K formed below the elastomer base 152 enable the movable part 152f to move.

[0165] As described above, the elastomer portion 23 has the same shape as the soft resin portion 23 of the first embodiment. The elastomer portion 23 stands vertically from the surface 152a of the elastomer base 152. In this embodiment, there are four elastomer portions 23, but the number of elastomer portions 23 is not limited to this. The elastomer portion 23 has a shaft portion 23A that stands vertically from the surface 152a of the elastomer base 152, an expanded portion 23B formed on the tip side of the shaft portion 23A, and a constricted portion 23C formed at the boundary between the shaft portion 23A and the expanded portion 23B.

[0166] According to the toothbrush 300 of this embodiment, as in the first and second embodiments, the continuous elasticity obtained by the complex movement (twisting behavior) of the elastomer part 323 enhances the massage effect on the gums, and the enlarged tip shape to improve the feel of the tip (enlarged part 23B) against the oral cavity makes it possible to achieve both a massage effect on the oral cavity and a gentle feel. [Explanation of symbols]

[0167] 1...toothbrush of first embodiment, 2...brush portion, 4...head portion, 4a...front, 21a...bristle bundle, 22...block, 23...soft resin portion, 23A...shaft portion, 23B...expanded portion, 23C...constricted portion, 24...base portion, A1...bristle implantation region (first region), A2...soft resin region (second region), d1...minimum distance between base portions 23a, d3...minimum distance between base portions 23a, D1...diameter of base 23a (maximum shaft width), D2...diameter of narrowest part of constricted portion 23C (minimum shaft width), D3...diameter of maximum shaft width of expanded portion 23B (maximum shaft width), H...total height of soft resin portion, H1...height from base end of soft resin portion 23 to boundary P (height of shaft portion 23A), H2...height to tip of expanded portion 23B, P...boundary, W1...total width, W2...width of base portion 24 100... toothbrush of second embodiment, 102... toothbrush body, 103... brush part, 104a... bristle bundle, 105... soft resin part, 121... handle part, 123... head part, 123a... bristle implantation surface, 123d... back surface of head part 123, 123g... hard resin side fixing part, 123h... first locking part, 123A... head constituent part (first resin part), 123B... soft resin containing part (second resin part), 151... elastomer part, 152... elastomer base, 152a... elastomer Surface of elastomer base 152, 152c...end of elastomer base 152, 152f...movable part, 153...second locking part, H...height, K...space, L1...length of head part 123, L2...length of movable part 152f, L3...length of soft resin part 105, Ls...length of gap S, T1...thickness of head part 123, T2...thickness of movable part 152f, W123...overall width of head part 123, W230...width of hard resin part 230, W3...width of elastomer base 152, WS...width of gap S 300... toothbrush of the third embodiment, 303... brush part, 305... soft resin part

Claims

1. A toothbrush having at least a head portion having a brush portion on the front, the brush portion has a plurality of soft resin portions standing upright from the front surface, The soft resin portion is a shaft portion standing upright relative to the front surface; an enlarged portion formed on the tip side of the shaft portion; a constricted portion formed at the boundary between the stem portion and the enlarged portion and narrower than at least the enlarged portion, In a normal direction of the front surface, the height of the shaft portion is greater than the height of the enlarged portion, a first resin portion that constitutes a part of the head portion and is made of a first resin; a plurality of second resin portions that constitute a part of the head portion and the brush portion and are made of a second resin; The second resin portion is the plurality of soft resin portions; an elastomer base connecting the base ends of the plurality of soft resin portions to each other, The elastomer base has a pair of ends on both sides of the head portion in the lengthwise or widthwise direction that are connected to the first resin part, and is separated from the first resin part by a gap that penetrates in the normal direction, and has a movable part that can move in the thickness and width directions of the elastomer base.

2. the shaft portion has a shape that tapers toward the constricted portion at least at a tip end side in the normal direction that is connected to the constricted portion, The enlarged portion has a shape that becomes thicker as it moves away from the constricted portion and then becomes thinner again from the position of maximum shaft width toward the tip. The toothbrush of claim 1.

3. the enlarged portion is spherical; The toothbrush according to claim 1 or 2.

4. The maximum axial width of the enlarged portion is in the range of 1.0 mm or more and 4.0 mm or less; The minimum axial width of the constricted portion is in the range of 0.8 mm or more and 3.0 mm or less; The maximum shaft width of the shaft portion is in the range of 1.0 mm or more and 4.0 mm or less. The toothbrush according to any one of claims 1 to 3.

5. The base cross-sectional area of ​​the shaft portion is X, The cross-sectional area of ​​the narrowest part of the constricted portion is Y, When the maximum cross-sectional area of ​​the expanded portion is Z, The value of Y / X is in the range of 0.2 or more and 0.75 or less, The value of Z / X is in the range of 0.25 or more and 2.0 or less. The toothbrush according to any one of claims 1 to 4.

6. In the plurality of adjacent soft resin portions, The minimum distance between the shaft portions is within a range of 0.5 mm or more and 2.0 mm or less; The minimum distance between the enlarged portions is in the range of 0.5 mm or more and 2.0 mm or less.

6. The toothbrush according to any one of claims 1 to 5.

7. a plurality of blocks each having the plurality of soft resin portions and a base portion connecting base ends of the plurality of soft resin portions; The head portion has a first region in which a plurality of tufts of hair are planted and a plurality of second regions in which the blocks are arranged, The sum of the widths of the plurality of second regions relative to the overall width of the head portion is 10.0% or more, 50. is within the range of 0% or less, 7. The toothbrush according to any one of claims 1 to 6.

8. The sum of the maximum cross-sectional areas of the enlarged portions is in the range of 15.0% to 70.0% of the total area of ​​the plurality of second regions.

8. The toothbrush of claim 7.

9. a total area of ​​the plurality of second regions is smaller than an area of ​​the first region; 9. The toothbrush according to claim 7 or 8.

10. The density of the bristle bundles in the first region is greater than the density of the soft resin portions in the second regions.

10. The toothbrush according to any one of claims 7 to 9.

11. an area of ​​the first region is larger than a sum of maximum cross-sectional areas of the enlarged portions in the plurality of soft resin portions; The toothbrush according to any one of claims 7 to 10.

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