Brush and toothbrush molding machine

Abstract

DEPCT67 A brush molding machine that can achieve improved freedom of movement in the bending direction to obtain... Both the good tactile feel and strong plaque-removing power, as well as the fact that it can be difficult to stick to curved shapes, are all factors to consider. It features a head base molded from soft resin and a number of protruding bristles. In the longitudinal direction from the support located on the front side, the thickness direction of the head base and... The bristles have one area with a flat cross-section perpendicular to the longitudinal axis, and a second area... Where the cross-section is flat and perpendicular to the longitudinal axis, the position of that longitudinal axis is different. From region one, in the direction of the first long side, where the flat long side extends to region one. It is a constant in the first region and the second longitudinal direction where the flat long side is stretched in. The second region is constant; in the second region, the first longitudinal direction and the second longitudinal direction intersect. When viewed in the longitudinal direction;

Description

Brush molded body and toothbrush

[0001] The present invention relates to a brush molding and a toothbrush. This application claims priority to Japanese Patent Application No. 2021-208244, filed on December 22, 2021, the contents of which are incorporated herein by reference.

[0002] One-piece molded toothbrushes, which are manufactured using only an injection molding machine, have been proposed (see, for example, Patent Document 1). One-piece molded toothbrushes have the advantage of being cheaper to manufacture than bristle-implanted toothbrushes because the filament and head base (or head) are molded as a single unit, eliminating the need for filament material procurement and a bristle implantation machine.

[0003] Due to the characteristics of the mold structure used in manufacturing integrally molded toothbrushes, the filaments often have a flat surface parallel to the minor axis direction of the toothbrush in order to ensure moldability, and as a result, the cross-sectional shape of the filaments is often made flat.

[0004] Since the filaments of an integrally molded toothbrush are produced by injection molding, each filament is thicker and farther apart than those of a regular toothbrush with rigid bristles, so it is necessary to improve the potential of each filament in terms of comfort and cleaning performance, etc. Since the filament material is limited to a relatively soft, rubber-like texture, it is necessary to increase rigidity to improve cleaning performance, but if it becomes too hard, the comfort of the filament will be insufficient.

[0005] Patent Document 2 discloses a configuration in which the cross-sectional shape of the base end region of the filament is "a shape that combines a triangle and a trapezoid to soften the edges," and the cross-sectional shape of the tip end region is designed to be "circular," thereby improving cleaning performance through appropriate bristles bending. Patent Document 2 also discloses a configuration in which a single filament has different cross-sectional shapes and gradually becomes thinner from the base end to the tip.

[0006] Patent Document 3 discloses a method for improving the degree of freedom in the bending direction by changing the orientation of one type of filament in order to prevent a decrease in the comfort of the toothbrush and to prevent plaque from being left behind when brushing.

[0007] Japanese Utility Model Publication No. 61-207233 Chinese Utility Model No. 205513169 Chinese Utility Model No. 206079549

[0008] The technology of Patent Document 2 ensures rigidity by imparting anisotropy to a single filament, but the flexure of both the tip and base regions of the bristles is linked and limited to the same direction according to the anisotropy, resulting in poor feel and poor cleaning performance. In other words, while anisotropy is effective in improving rigidity, a method that does not limit rigidity to a specific direction is needed. Furthermore, in integrally molded toothbrushes, the difference between the thickness of the filament tip and the base tends to be greater compared to toothbrushes with rigid bristles in order to ensure resin fluidity all the way to the bristles. This tends to concentrate brushing pressure at the tips of the bristles, making them prone to curling. While thinning the base of the bristles as a method to prevent curling significantly reduces moldability, a method to distribute brushing pressure in multiple directions within a single filament is needed.

[0009] The technology of Patent Document 3 creates areas that are difficult to bend locally, which causes an imbalance in the flexibility of the entire filament, and as a result, it does not solve the problems of a reduced feel and leaving plaque unbrushed.

[0010] The present invention has been made in consideration of the above points, and aims to provide a brush molding and toothbrush that can improve the degree of freedom in the bending direction, thereby achieving both a comfortable feel and plaque removal power, and that is less likely to become bent.

[0011] The present invention has the following aspects. [1] A brush molded body comprising: a head base formed of a soft resin; and a plurality of filaments extending in a long axis direction from a support surface located on the front side in the thickness direction of the head base, wherein the filaments have: a first region having a flat cross section perpendicular to the long axis direction; and a second region having a flat cross section perpendicular to the long axis direction, the cross section being located at a different position in the long axis direction from the first region, wherein a first long side direction in which a long side of the flat shape in the first region extends is constant in the first region, and a second long side direction in which a long side of the flat shape in the second region extends is constant in the second region, and the first long side direction and the second long side direction intersect when viewed in the long axis direction. [2] A brush molded body according to [1], wherein the smaller angle between the first long side direction and the second long side direction is 60° or greater. [3] The brush molded body according to [1] or [2], wherein the first region is located closer to the tip end in the major axis direction than the second region, and the long side of the first region is a line segment formed along the length direction of the head base portion perpendicular to the thickness direction. [4] The brush molded body according to any one of [1] to [3], wherein the cross-sectional shapes of the first region and the second region are similar and vary or are constant, and the lengths of the first region and the second region in the major axis direction are each 1.5 mm or more. [5] The maximum length of the long side of the second region is W(B), and the length of the short side at the position in the major axis direction in the second region where the long side has the maximum length is D(B), and the deflection coefficient in the second major axis direction in the cross section of the second region is DW. ３ (B), and in the cross section in the second region, a deflection coefficient in a second short side direction perpendicular to the second long side direction is WD ３ If (B), then DW ３ (B) / WD ３The value represented by (B) is 1.4 or more and 4.0 or less, and the maximum length of the long side in the first region is W(A), and the length of the short side at the position in the long axis direction where the long side in the first region has the maximum length is D(A), and the deflection coefficient in the first long side direction in the cross section of the first region is DW(A). ３ (A), and in the cross section of the first region, a deflection coefficient in a first short side direction perpendicular to the first long side direction is WD ３ If (A), then DW ３ (A) / WD ３ [6] The brush molded body according to any one of [1] to [4], wherein the value represented by (A) is 1.4 or more and 9.0 or less. ３ (B) / WD ３[7] The brush molded body according to any one of [1] to [6], wherein the value represented by (A) is 4.0 or more and 80.0 or less. [7] The brush molded body according to any one of [1] to [6], wherein, in the cross section of the second region, the position in the longitudinal direction where the aspect ratio is largest is within a range between a position that is 75% of the length of the filament in the longitudinal direction from the support surface and the support surface, and, in the cross section of the first region, the position in the longitudinal direction where the aspect ratio is largest is within a range between a position that is 50% of the length of the filament in the longitudinal direction from the support surface and the tip of the filament. [8] The brush molded body according to any one of [1] to [7], wherein, in the cross section between the first region and the second region, the filament includes a region where the aspect ratio is 1:1. [9] The brush molded body according to any one of [1] to [7], wherein the filament has a third region in a range extending from a first boundary of the first region on the side of the second region toward the second region toward the first region, the third region having a flattened cross section perpendicular to the longitudinal direction, and a third long side direction in which a long side of the flat shape of the third region extends gradually changes in a circumferential direction about a center line extending in the longitudinal direction from the same direction as the first long side direction at the first boundary to the same direction as the second long side direction at the second boundary.

[10] A toothbrush comprising the brush molded body according to any one of [1] to [9], wherein the head base has a fitting hole extending in a longitudinal direction perpendicular to the thickness direction and opening to one side in the longitudinal direction, and the toothbrush further comprises a handle body made of a hard resin and having a fitting protrusion that fits into the fitting hole.

[11] A toothbrush comprising: the brush molded body according to any one of [1] to [9]; and a handle body made of hard resin and supporting the brush molded body, wherein the brush molded body and the handle body are an integrally molded body.

[0012] In the brush molded body and toothbrush of the present invention, the degree of freedom in the bending direction is improved, thereby achieving both a comfortable feel and plaque removal power, and making it less likely to become bent.

[0013] 1 is a front view of a brush molded body 20 and a toothbrush 1 according to an embodiment of the present invention. FIG. 2 is a side view of the brush molded body 20 and a toothbrush 1. FIG. 3 is a front view of a handle body 10. FIG. 4 is an enlarged front view of a fitting protrusion 12. FIG. 5 is a front view of the brush molded body 20. FIG. 6 is a side view of the brush molded body 20. FIG. 7 is a cross-sectional view of a plane parallel to the support surface 21a and including the fitting hole 22. FIG. 8 is a view of the filament 23 from the front side. FIG. 9 is a view of the filament 23 as viewed in the length direction of the handle body 10. FIG. 10 is a cross-sectional view of the filament 23 in the first region F1. FIG. 11 is a cross-sectional view of the filament 23 in the second region F2. FIG. 11 is a view of the filament 23 of a second embodiment as viewed from the front side. FIG. 12 is a view of the filament 23 of a third embodiment as viewed from the front side. FIG. 13 is a view of the filament 23 of the third embodiment as viewed in the length direction of the handle body 10.

[0014] Hereinafter, embodiments of the brush molded body and toothbrush of the present invention will be described with reference to Figures 1 to 14. In this embodiment, an example of a toothbrush in which the brush molded body is detachably attached to the handle body will be described.

[0015] 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.

[0016] FIG. 1 is a front view of a brush molded body 20 and toothbrush 1 according to this embodiment. FIG. 2 is a side view of the brush molded body 20 and toothbrush 1. The toothbrush 1 comprises a rod-shaped handle body 10 and a brush molded body 20. The handle body 10 and the brush molded body 20 are separate components. The brush molded body 20 can be detachably attached (inserted) to the handle body 10. The brush molded body 20 attached to the handle body 10 is supported by the handle body 10. The brush molded body 20 is made of a soft resin. The handle body 10 is made of a hard resin. Note that a cap-type brush molded body that can be detachably attached (inserted) to the handle body 10 is an example, but is not limited to this.

[0017] In this embodiment, the front side refers to the side from which the filaments 23 (described later) protrude (the upper side in FIG. 2 ) in the thickness direction (hereinafter simply referred to as the thickness direction), which is the normal direction to the support surface 21 a (described in detail later) of the brush mold 20. In the thickness direction of the brush mold 20, the side opposite the front side is referred to as the rear side as appropriate. The length direction of the handle body 10, which is the direction in which the handle body 10 is inserted into the brush mold 20 (hereinafter simply referred to as the insertion direction), is perpendicular to the normal direction. In the length direction, the side in which the handle body 10 is attached to the brush mold 20 is referred to as the rear end side, and the side opposite the rear end side is referred to as the front end side as appropriate. The direction perpendicular to the normal direction and the insertion direction is the width direction of the brush mold 20 (hereinafter simply referred to as the width direction). In this embodiment, the long axis direction refers to the direction in which the filaments 23 extend, which is parallel to the normal direction.

[0018] Figure 3 is a front view of the handle body 10. As shown in Figure 3, the handle body 10 comprises a rod-shaped handle portion 11 and a fitting protrusion 12 provided at the tip of the handle portion 11 and protruding toward the tip end in the longitudinal direction of the handle portion 11. In the toothbrush 1, the fitting protrusion 12 of the handle body 10 is inserted into the brush molded body 20 (described below), and the brush molded body 20 is attached by covering the fitting protrusion 12.

[0019] The handle body 10 is made of a hard resin. Examples of hard resins include resins with a flexural modulus (JIS K7171) of 1500 MPa or more and 3000 MPa or less. Specific examples include polypropylene resin (PP), polyacetal resin (POM), polyester resin (PCTA), polyethylene terephthalate copolymer (PETG), and high-density polyethylene (HDPE). Among these, PP, a general-purpose resin, is preferred in terms of cost.

[0020] In this embodiment, the handle portion 11 has a shape in a front view that gradually narrows from the tip end to the rear end, then extends at a constant width, then gradually widens, and then narrows again in a curved manner. The handle portion 11 has a substantially semicircular rear end in a front view.

[0021] As shown in Figure 2, the handle portion 11 has a side view shape that extends from the tip end toward the rear end with a constant width and then gradually widens until it reaches its maximum thickness, which is the finger rest portion. The side view shape of the handle portion 11 curves so that the width gradually narrows from the finger rest portion, which is the maximum thickness, toward the rear end. The side view shape of the handle portion 11 has a substantially semicircular rear end.

[0022] In the present invention, the shape of the handle portion 11 is not limited to the shape in this example, and can be set appropriately taking into consideration strength, operability, design, etc. The dimensions of the handle portion 11 are not particularly limited, and can be set appropriately. For example, the length of the handle portion 11 can be 100 to 200 mm.

[0023] The fitting protrusion 12 is a portion that is covered by the brush body 20 when the brush body 20 is attached to the handle body 10. The rear end of the fitting protrusion 12 is the rear end position of the brush body 20 when the brush body 20 is attached to the handle body 10.

[0024] Figure 4 is an enlarged front view of the fitting protrusion 12. As shown in Figure 4, the fitting protrusion 12 has a base 13 provided on the tip side of the handle portion 11 and a tip portion 14 provided at the tip of the base 13. Although not shown in the figure, the base 13 and the tip portion 14 have steps on both the front and back sides relative to the handle portion 11 and are formed to have the same thickness that is thinner than the handle portion 11.

[0025] Fig. 5 is a front view of the brush molded body 20. Fig. 6 is a side view of the brush molded body 20. As shown in Figs. 5 and 6, the brush molded body 20 includes a head base 21 that is substantially rectangular in shape when viewed from the front, and a plurality of filaments 23 provided on the front surface of the head base 21.

[0026] Although various elastomers can be used as the soft resin that constitutes the brush molded body 20, polyurethane is preferred. Polyurethane tends to have higher tensile strength than other elastomers such as styrene-based or polyester-based elastomers, so by using polyurethane as the soft resin, mechanical strength can be ensured even when the brush molded body 20 is thin, and breakage can be suppressed when the handle body 10 is fitted into the fitting hole 22 and when the toothbrush 1 is in use.

[0027] The polyurethane contains 0.01 to 1.0 wt% (mass%) of any one of saturated / unsaturated hydrocarbons of C10 or higher, higher alcohols, fatty acid amides, fatty acid esters, low-molecular-weight polyethylene, polyethylene glycol (PEG), fatty acid metal salts, long-chain fatty acids, fatty acid glycerin, liquid paraffin, and silicone, or a combination thereof, which function as a lubricant and mold release agent.

[0028] Furthermore, compared to the other elastomers mentioned above, polyurethane offers a wider range of hardness options, allowing for selection of resin hardness taking into account usability (e.g., bending of the brush tip) depending on the thickness of the brush molded body 20. The polyurethane hardness is preferably at least 90A Shore and no more than 70D Shore. Polyurethanes with a hardness softer than 90A Shore are prone to deformation when formed with thin walls, resulting in weaker fit and making the brush molded body 20 more likely to fall off during use of the toothbrush 1. Polyurethanes with a hardness harder than 70D Shore may cause pain when the tip of the head base 21 hits oral tissue if the back surface of the head base 21 is tilted. By setting the polyurethane hardness to at least 90A Shore and no more than 70D Shore, it is possible to prevent the brush molded body 20 from falling off during use of the toothbrush 1 or to prevent pain when the tip of the head base 21 hits oral tissue.

[0029] As the polyurethane, it is preferable to use an ether-based polyurethane from the viewpoint of ensuring water resistance and antibacterial properties.

[0030] The head base 21 has a fitting hole 22. The fitting hole 22 extends in the insertion direction and opens to an end face 21b on the rear end side (one side). FIG. 7 is a cross-sectional view of a plane parallel to the support surface 21a and including the fitting hole 22. As shown in FIG. 7, the fitting hole 22 has a first portion 33 that opens to the end face 21b and a second portion 34 that is located further back than the first portion 33. As shown in FIG. 6, the first portion 33 and the second portion 34 are disposed spaced apart from the support surface 21a and the back surface 21c of the head base 21, respectively.

[0031] The head base 21 has a protrusion 35 located approximately in the center of the fitting hole 22 in the insertion direction, between the first portion 33 and the second portion 34. The protrusions 35 are provided on both sides in the width direction of the fitting hole 22. The protrusions 35 are each provided at a position that will fit into the recess 15 when the fitting protrusion 12 of the handle body 10 is inserted into the fitting hole 22. The protrusion 35 has an arc shape that has an arc center on the outside in the width direction and is convex inward.

[0032] When the fitting protrusion 12 of the handle body 10 is inserted into the fitting hole 22 of the head base 21, the base 13 fits into the first portion 33, the tip 14 fits into the second portion 34, and the protrusion 35 fits into the recess 15. As a result, the handle body 10 and the head base 21 are integrated.

[0033] [First embodiment of filament 23] The filament 23 has a generally columnar shape that protrudes forward from a support surface 21a located on the front side in the thickness direction of the head base 21 and extends in the longitudinal direction. The support surface 21a of the head base 21 is a flat surface that is parallel to the width direction and the insertion direction. The support surface 21a is located at the base end position of the filament 23 in the thickness direction.

[0034] Figure 8 is a view of the filament 23 as seen from the front side. Figure 9 is a view of the filament 23 as seen in the longitudinal direction of the handle body 10. In the following description, the longitudinal direction of the filament 23 (thickness direction of the brush molded body 20) is defined as the Z direction, the longitudinal direction of the handle body 10 is defined as the Y direction, and the width direction of the brush molded body 20, which is perpendicular to the Z direction and Y direction, is defined as the X direction.

[0035] Each filament 23 has a first region F1, a second region F2, and a third region F3. As shown in FIG. 8 , the cross section of the filament 23 in the first region F1 perpendicular to the Z direction (hereinafter simply referred to as the "cross section") has a flattened shape with the major axis in the Y direction and the minor axis in the X direction. That is, the cross-sectional shape of the first region F1 is anisotropic. The cross section of the filament 23 in the second region F2 perpendicular to the Z direction has a flattened shape with the major axis in the X direction and the minor axis in the Y direction. That is, the cross-sectional shape of the second region F2 is anisotropic. As shown in FIG. 9 , the first region F1 is located at the distal end of the filament 23 in the Z direction. The second region F2 is located at a different position in the Z direction from the first region F1. The second region F2 is located at the proximal end of the filament 23 in the Z direction. When the tip position of the filament 23 in the Z direction is position Z0 and the base position is position Z11, the first region F1 is located from position Z0 to position Z4 on the tip side of the filament 23, and the second region F2 is located from position Z6 to position Z11 on the base side of the filament 23. Figure 8 shows the outer contour of the cross section at each position from position Z0 to position Z11.

[0036] 10 is a cross-sectional view of the filament 23 in the first region F1. As shown in FIG. 10, the cross-sectional shape of the filament 23 in the first region F1 is an ellipse with a long side L1 extending in a first long side direction LD1 parallel to the Y direction and a short side S1 parallel to the X direction. The long side L1 of the filament 23 in the first region F1 is a line segment formed along the Y direction. In the first region F1, the first long side direction LD1 is constant from position Z0 to position Z4. In the first region F1, the first long side direction LD1 is parallel to the Y direction and is constant from position Z0 to position Z4, so that the filament 23 in the first region F1 is more likely to bend in the X direction.

[0037] Table 1 shows the length of the long side L1, the length of the short side S1, and the aspect ratio represented by L1 / S1 at each position from position Z0 to position Z4. As shown in Table 1, the length of the long side L1 and the length of the short side S1 of the filament 23 in the first region F1 gradually increase from position Z0 to position Z4, and the aspect ratio also increases.

[0038]

[0039] 11 is a cross-sectional view of the filament 23 in the second region F2. As shown in FIG. 11 , the cross-sectional shape of the filament 23 in the second region F2 is elliptical, with the long side L2 extending in a second long side direction LD2 parallel to the X direction in the second region F2 and the short side S2 parallel to the Y direction. In the second region F2, the second long side direction LD2 is constant from position Z6 to position Z11. In the second region F2, the second long side direction LD2 is parallel to the X direction and is constant from position Z6 to position Z11, so that the filament 23 in the second region F2 is more likely to bend in the Y direction.

[0040] Table 2 shows the length of the long side L2, the length of the short side S2, and the aspect ratio (L2 / S2) at each position from position Z6 to position Z11. As shown in Table 2, the length of the long side L2 and the length of the short side S2 of the filament 23 in the second region F2 gradually increase from position Z6 to position Z11, and the aspect ratio also increases.

[0041]

[0042] The first region F1 located at the distal end of the filament 23 and the second region F2 located at the proximal end have different anisotropies and work together to allow the filament 23 to bend in various directions depending on the brushing load and brushing direction applied to the filament 23. In particular, since the toothbrush 1 is often stroked in the Y direction, which is the longitudinal direction of the handle body 10, the fact that the first region F1 located at the bristles of the filament 23 is easily bent in the width direction of the toothbrush 1 contributes to further improving cleaning performance and feel. In other words, if the first region F1 is easily bent in the width direction, the contact area between the bristles and the teeth and gums can be increased, contributing to improved cleaning performance by preventing plaque from being left behind. Furthermore, if the first region F1 is easily bent in the width direction, the rigidity of the proximal end in the longitudinal direction can be distributed in the width direction, thereby contributing to improved feel while maintaining cleaning performance.

[0043] When viewed in the Z direction, the first long side direction LD1 and the second long side direction LD2 intersect. The first long side direction LD1 and the second long side direction LD2 intersect when viewed in the Z direction. This means that the intersection angle between the first long side direction LD1 and the second long side direction LD2 is at least 10° or greater. More specifically, when viewed in the Z direction, the smaller of the intersection angles between the first long side direction LD1 and the second long side direction LD2 is preferably 60° or greater, more preferably 75° or greater, and even more preferably 85° or greater. If the smaller of the intersection angles between the first long side direction LD1 and the second long side direction LD2 is less than 60°, the difference between the anisotropy of the first region F1 and the anisotropy of the second region F2 may be insufficient, resulting in a reduced degree of freedom in the bending direction. Preferably, when viewed in the Z direction, the first long side direction LD1 and the second long side direction LD2 are perpendicular to each other at an intersection angle of 90°, so that each filament 23 is more likely to bend in the X direction in the first region F1 and more likely to bend in the Y direction in the second region F2, improving the degree of freedom in the bending direction.

[0044] "The first long side direction LD1 being constant in the first region F1" is defined as "the first long side direction LD1 in the first region F1 is within 15° in the circumferential direction (hereinafter simply referred to as the circumferential direction) centered on the center line J of the filament 23 extending in the Z direction, as shown in Fig. 9." Similarly, "the second long side direction LD2 being constant in the second region F2" is defined as "the second long side direction LD2 in the second region F2 is within 15° in the circumferential direction centered on the center line J." When at least one of the first long side direction LD1 in the first region F1 and the second long side direction LD2 in the second region F2 varies within 15° in the circumferential direction, it is sufficient that the intersection angle between the first long side direction LD1 and the second long side direction LD2 in the second region F2 is at least 10° or more, in the closest angular relationship in the circumferential direction.

[0045] When the first long side direction LD1 and the second long side direction LD2 are each in a range exceeding 15° in the circumferential direction, the sharpness obtained by the flat cross section and anisotropy is reduced, but when they are within a range of 15° in the circumferential direction, the sharpness obtained by the flat cross section and anisotropy is expressed.

[0046] The flat cross-sectional shape of the filament 23 in the first region F1 and the second region F2 may be an ellipse, an oblong shape, a rectangle, a triangle, or another polygonal shape. The aspect ratio of the cross-section of the first region F1 is preferably 1.2 (6.0:5.0) or more, and more preferably 1.4 (7.0:5.0) or more. The aspect ratio of the cross-section of the first region F1 is preferably 3.0 (3.0:1.0) or less, and more preferably 2.5 or less. The aspect ratio of the cross-section of the first region F1 is preferably 1.2 (6.0:5.0) or more and 3.0 (3.0:1.0) or less, and more preferably 1.4 (7.0:5.0) or more and 2.5 or less. The aspect ratio of the cross-section of the second region F2 is preferably 1.1 (11.0:10.0) or more, and more preferably 1.2 (7.0:5.0) or more. The aspect ratio of the cross section of the second region F2 is preferably 3.0 (3.0:1.0) or less, more preferably 2.5 or less. The aspect ratio of the cross section of the second region F2 is preferably 1.1 (11.0:10.0) or more and 3.0 (3.0:1.0) or less, more preferably 1.2 (7.0:5.0) or more and 2.5 or less. If the aspect ratio of the cross section of the first region F1 is less than 1.2 and the aspect ratio of the cross section of the second region F2 is less than 1.1, the anisotropy may be insufficient, resulting in a low degree of freedom in the bending direction. If the aspect ratio exceeds 3.0, the anisotropy may be too large, resulting in insufficient linkage between the bending in the first region F1 and the bending in the second region F2.

[0047] The maximum length of the long side L2 of the cross section of the filament 23 in the second region F2 is W(B), the length of the short side S2 at the position in the Z direction where the long side L2 has the maximum length W(B) is D(B), and the deflection coefficient in the second long side direction LD2 of the cross section of the filament 23 in the second region F2 is DW(B). ３ (B), and the deflection coefficient in the second short side direction SD2 perpendicular to the second long side direction LD2 is WD ３ (B). The deflection coefficient DW ３ (B) and the deflection coefficient WD３ (B) is in mm ４ However, in the following explanation, the units may be omitted.

[0048] The length W(B) is preferably 0.30 mm or more, and more preferably 0.40 mm or more. The length W(B) is preferably 1.0 mm or less. Furthermore, the length W(B) is preferably 0.30 mm or more and 1.0 mm or less, and more preferably 0.40 mm or more and 1.0 mm or less. The length D(B) is preferably 0.25 mm or more, and more preferably 0.35 mm or more. The length D(B) is preferably 0.85 mm or less. Furthermore, the length D(B) is preferably 0.25 mm or more and 0.85 mm or less, and more preferably 0.35 mm or more and 0.85 mm or less. If the length D(B) exceeds 0.85 mm, the film will be less flexible in both the Y direction and the X direction, resulting in insufficient anisotropy.

[0049] D.W. ３ (B) / WD ３ The value indicating the degree of anisotropy in the second region F2 represented by (B) is preferably 1.4 or more and 4.0 or less. ３ (B) / WD ３ If the value represented by (B) is less than 1.4, the anisotropy is insufficient and the degree of freedom in the bending direction is reduced. ３ (B) / WD ３ If the value represented by (B) exceeds 4.0, the anisotropy of the second region F2 becomes too large, and the linkage between the deflection in the first region F1 and the deflection in the second region F2 may become insufficient. ３ (B) / WD ３ By setting the value represented by (B) to 1.4 or more and 4.0 or less, it is possible to improve the degree of freedom in the bending direction while ensuring the linkage between the bending in the first region F1 and the bending in the second region F2.

[0050] D.W. ３ (B) / WD ３ Considering that the value represented by (B) is 1.4 or more and 4.0 or less, the length W(B), the length D(B), the deflection coefficient WD３ (B) and the deflection coefficient DW ３ The following ranges can be exemplified for (B): Length W(B) = 0.30 mm or more and 1.0 mm or less; Length D(B) = 0.25 mm or more and 0.85 mm or less; Deflection coefficient WD ３ (B) is 0.0047 or more, preferably 0.014 or more. ３ (B) = 0.58 or less. Also, the deflection coefficient WD ３ (B) = 0.0047 or more and 0.58 or less, preferably 0.014 or more and 0.58 or less. Deflection coefficient DW ３ (B) is 0.0068 or more, preferably 0.021 or more. ３ (B) = 0.85 or less. Also, the deflection coefficient DW ３ (B) is 0.0068 or more and 0.85 or less, preferably 0.021 or more and 0.85 or less.

[0051] The maximum length of the long side L1 of the cross section of the filament 23 in the first region F1 is W (A), the length of the short side S1 at the position in the Z direction where the long side L1 has the maximum length W (A) is D (A), and the deflection coefficient in the first long side direction LD1 of the cross section of the filament 23 in the first region F1 is DW ３ (A), and the deflection coefficient in the first short side direction SD1 perpendicular to the first long side direction LD1 is WD ３ (A). The deflection coefficient DW ３ (A) and deflection coefficient WD ３ (A) is in mm ４ However, in the following explanation, the units may be omitted.

[0052] The length W(A) is preferably 0.01 mm or more, and more preferably 0.12 mm or more. The length W(A) is preferably 0.50 mm or less, and more preferably 0.40 mm or less. Furthermore, the length W(A) is preferably 0.01 mm or more and 0.50 mm or less, and more preferably 0.12 mm or more and 0.40 mm or less. The length D(A) is preferably 0.01 mm or more and more preferably 0.10 mm or more. The length D(A) is preferably 0.50 mm or less and more preferably 0.33 mm or less. Furthermore, the length D(A) is preferably 0.01 mm or more and 0.50 mm or less, and more preferably 0.10 mm or more and 0.33 mm or less. If the length W(A) is less than 0.01 mm, the film will be easily bent in both the Y direction and the X direction, making the anisotropy unclear.

[0053] D.W. ３ (A) / WD ３ The value indicating the degree of anisotropy in the first region F1 represented by (A) is preferably 1.4 or more and 9.0 or less. ３ (A) / WD ３ If the value represented by (A) is less than 1.4, the anisotropy is insufficient and the degree of freedom in the bending direction is reduced. ３ (A) / WD ３ If the value represented by (A) exceeds 9.0, the anisotropy of the first region F1 becomes too large, and the linkage between the deflection in the first region F1 and the deflection in the second region F2 may become insufficient. ３ (A) / WD ３ By setting the value represented by (A) to 1.4 or more and 9.0 or less, it is possible to improve the degree of freedom in the bending direction while ensuring the linkage between the bending in the first region F1 and the bending in the second region F2.

[0054] D.W. ３ (A) / WD ３ Considering that the value represented by (A) is 1.4 or more and 9.0 or less, the length W(A), the length D(A), the deflection coefficient WD ３ (A) and deflection modulus DW ３The following ranges can be exemplified for (A): Length W(A) = 0.12 mm or more and 0.40 mm or less; Length D(A) = 0.10 mm or more and 0.33 mm or less; Deflection coefficient WD ３ (A) = 0.00012 or more. Deflection coefficient WD ３ (A) is 0.037 or less, preferably 0.014 or less. ３ (A) = 0.00012 or more and 0.037 or less, preferably 0.00012 or more and 0.014 or less. Deflection coefficient DW ３ (A) = 0.00017 or more. Deflection coefficient DW ３ (A) is 0.053 or less, preferably 0.021 or less. ３ (A) is 0.00017 or more and 0.053 or less, preferably 0.00017 or more and 0.021 or less.

[0055] Also, W.D. ３ (B) / WD ３ The value represented by (A) is 4.0 or more and 80.0 or less. ３ (B) / WD ３ The value represented by (A) indicates the ease with which anisotropy is exhibited in the first region F1 and the second region F2. ３ (B) / WD ３ If the value represented by (A) is less than 4.0, the direction in which the first region F1 is likely to bend and the direction in which the second region F2 is likely to bend become unclear, and even if the directions in which the first region F1 is likely to bend are different, the sharpness obtained by having anisotropy in a flat cross section is reduced. ３ (B) / WD ３ If the value represented by (A) exceeds 80.0, the first region F1 becomes extremely prone to bending, and the linkage between the bending in the first region F1 and the bending in the second region F2 may be insufficient. Therefore, it is preferable to satisfy the relationship 1.5≦length D(B) / length D(A)≦3.0.

[0056] For example, when the dimensions of the second region F2 are smallest, if the length W(B) of the long side L1 is 0.30 mm and the length D(B) of the short side S2 is 0.25 mm, then WD ３In this case, if the minimum possible length of the long side L1 in the first region F1 is W(A) = 0.12 mm and the minimum possible length of the short side S1 is D(A) = 0.10 mm, then WD ３ (A) = 0.00012. In this case, WD ３ (B) / WD ３ On the other hand, in this case, the maximum possible length of the long side L1 in the first region F1 is W(A) = 0.20 mm, and the maximum possible length of the short side S1 is D(A) = 0.17 mm. ３ (A) = 0.00098. In this case, WD ３ (B) / WD ３ Therefore, even when the size of the second region F2 is smallest, the value represented by WD ３ (B) / WD ３ The value represented by (A) satisfies the requirement of 4.0 or more and 80.0 or less.

[0057] For example, when the dimension of the second region F2 is the largest, if the length W(B) of the long side L1 is 1.0 mm and the length D(B) of the short side S2 is 0.85 mm, then WD ３ In this case, if the minimum possible length of the long side L1 in the first region F1 is W(A) = 0.34 mm and the minimum possible length of the short side S1 is D(A) = 0.28 mm, then WD ３ (A) = 0.0075. In this case, WD ３ (B) / WD ３ On the other hand, in this case, the maximum possible length of the long side L1 in the first region F1 is W(A) = 0.68 mm, and the maximum possible length of the short side S1 is D(A) = 0.57 mm. ３ (A) = 0.13. In this case, WD ３ (B) / WD ３ Therefore, even if the dimension of the second region F2 is the largest, the value represented by WD ３ (B) / WD ３ The value represented by (A) satisfies the requirement of 4.0 or more and 80.0 or less.

[0058] W.D. ３ (B) / WD ３Considering that the value represented by (A) is 4.0 or more and 80.0 or less, the deflection coefficient WD ３ (B) is 0.0047 or more and preferably 0.60 or less, and the deflection coefficient WD ３ (A) is preferably 0.00012 or more and 0.13 or less when the relationship 1.5≦length D(B) / length D(A)≦3.0 is satisfied.

[0059] In the cross section of the second region F2, the position in the Z direction where the aspect ratio is largest is preferably within a range between the support surface 21a and a position that is 75%, preferably 50%, of the Z direction length of the filament 23 from the support surface 21a. If, in the cross section of the second region F2, the position in the Z direction where the aspect ratio is largest is located closer to the tip side than the position that is 75% of the Z direction length of the filament 23, the range of the first region F1 becomes shorter, and the anisotropy of the tip side of the filament 23 becomes insufficient.

[0060] In the cross section of the first region F1, the position in the Z direction where the aspect ratio is greatest is preferably located between the position that is 50% of the Z direction length of the filament 23 from the support surface 21a and the tip of the filament 23. If, in the cross section of the first region F1, the position in the Z direction where the aspect ratio is greatest is located closer to the base end than the position that is 50% of the Z direction length of the filament 23, the range of the second region F2 becomes shorter, and the anisotropy of the base end side of the filament 23 becomes insufficient.

[0061] It is preferable that the position in the Z direction where the aspect ratio is largest in the cross section of the first region F1 is at least 1.5 mm away from the position in the Z direction where the aspect ratio is largest in the cross section of the second region F2.

[0062] The Z-direction length of the first region F1 is preferably 1.5 mm or more, and more preferably 2.0 mm or more. The Z-direction length of the first region F1 is preferably 5.5 mm or less, and more preferably 4.0 mm or less. The Z-direction length of the first region F1 is preferably 1.5 mm or more and 5.5 mm or less, and more preferably 2.0 mm or more and 4.0 mm or less. The Z-direction position of the first region F1 is preferably within a range of 50% or more, and more preferably within a range of 60% or more, of the Z-direction length of the filament 23 from the support surface 21a. The Z-direction position of the first region F1 is preferably within a range of 100% or less, and more preferably within a range of 80% or less, of the Z-direction length of the filament 23 from the support surface 21a. Furthermore, the Z-direction position of the first region F1 is preferably within a range from 50% to 100% of the Z-direction length of the filament 23 from the support surface 21a, and more preferably within a range from 60% to 80%.

[0063] The Z-direction length of the second region F2 is preferably 1.5 mm or more, and more preferably 2.0 mm or more. The Z-direction length of the second region F2 is preferably 9.5 mm or less, and more preferably 8.0 mm or less. The Z-direction length of the second region F2 is preferably 1.5 mm or more and 9.5 mm or less, and more preferably 2.0 mm or more and 8.0 mm or less. The Z-direction position of the second region F2 is preferably within a range from the support surface 21 a to a position corresponding to 75% of the Z-direction length of the filament 23, more preferably within a range from the support surface 21 a to a position corresponding to 70% of the Z-direction length of the filament 23, and even more preferably within a range from the support surface 21 a to a position corresponding to 65% of the Z-direction length of the filament 23.

[0064] A tapered region having a length of, for example, 1.0 mm or less and not included in the first region F1 may be provided on the distal side of the first region F1, and a region having a length of, for example, 8.0 mm or less and not included in the second region F2 may be provided on the proximal side of the second region F2.

[0065] The tip shape of the filament 23 may be branched. Each branched hair in the branched region may have anisotropy. When each branched hair in the branched region has anisotropy, if 50% or more of the number of branches have the above-mentioned anisotropy, the filament becomes more likely to bend in the short side direction according to the anisotropy, and a sufficient effect of improving the degree of freedom in the bending direction can be exhibited. Alternatively, the branched region may not have anisotropy, and a first region F1 and a second region F2 having different anisotropies may be present on the base end side of the branched region.

[0066] The third region F3 is located in the filament 23 from position Z4 to position Z6. The third region continuously connects the outer shapes of the first region F1 and the second region F2. The cross-sectional shape of the filament 23 at position Z5 of the third region F3 is circular. That is, the filament 23 includes the third region F3 having an aspect ratio of 1:1 in the cross section between the first region F1 and the second region F2. The outer shape of the filament 23 in the third region F3 continuously changes from an elliptical cross section extending in a first long side direction LD1, in which the long side L1 is parallel to the Y direction, at position Z4 to a circular cross section at position Z5. The outer shape of the filament 23 in the third region F3 continuously changes from a circular cross section at position Z5 to an elliptical cross section extending in a second long side direction LD2, in which the long side L2 is parallel to the X direction, at position Z6.

[0067] The third region F3, which has no anisotropy in the bending direction, is provided between the first region F1 and the second region F2, so that the anisotropies in different directions of the first region F1 and the second region F2 can be more clearly defined. The length of the third region F3 in the Z direction is, for example, 0.10 mm or more and 1.0 mm or less.

[0068] In the filament 23 other than the first region F1, the second region F2, and the third region F3, it is also possible to provide a region whose cross-sectional shape is different from that of the first region F1, the second region F2, and the third region F3.

[0069] As explained above, the brush molding 20 and toothbrush 1 of this embodiment have a first region F1 and a second region F2 with a flat cross section, and the first long side direction LD1 of the first region F1 and the second long side direction LD2 of the second region F2 intersect when viewed in the Z direction, thereby improving the degree of freedom in the bending direction. Therefore, the brush molding 20 and toothbrush 1 of this embodiment can achieve both a comfortable feel and plaque removal power, and can suppress the concentration of brushing pressure on the bristles, making them less likely to bend.

[0070] [Second Embodiment of Filament 23] Next, a second embodiment of the filament 23 will be described with reference to Fig. 12. Fig. 12 is a front view of the filament 23 of the second embodiment. In this figure, the same elements as those of the first embodiment shown in Figs. 1 to 11 are designated by the same reference numerals, and their description will be omitted.

[0071] 12, the first region F1 is located from position Z0 to position Z4 on the tip side of the filament 23, and the second region F2 is located from position Z6 to position Z11 on the base side of the filament 23. In FIG. 12, the outer contour of the cross section at each position from position Z0 to position Z11 is shown.

[0072] 10 , the cross-sectional shape of the filament 23 in the first region F1 is an ellipse with a long side L1 extending in a first long side direction LD1 parallel to the Y direction and a short side S1 parallel to the X direction. In the first region F1, the first long side direction LD1 is constant from position Z0 to position Z4. In the first region F1, the first long side direction LD1 is parallel to the Y direction and is constant from position Z0 to position Z4, so that the filament 23 in the first region F1 is more likely to bend in the X direction.

[0073] Table 3 shows the length of the long side L1, the length of the short side S1, and the aspect ratio (L1 / S1) at each position from position Z0 to position Z4. As shown in Table 3, the length of the long side L1 and the length of the short side S1 of the filament 23 in the first region F1 gradually increase from position Z0 to position Z4 at a constant aspect ratio (1.40). In other words, the cross-sectional shapes of the filament 23 in the first region F1 are similar.

[0074]

[0075] 11 , the cross-sectional shape of the filament 23 in the second region F2 is elliptical, with the long side L2 extending in a second long side direction LD2 parallel to the X direction and the short side S2 parallel to the Y direction in the second region F2. The second long side direction LD2 in the second region F2 is constant from position Z6 to position Z11. Since the second long side direction LD2 in the second region F2 is parallel to the X direction and constant from position Z6 to position Z11, the filament 23 in the second region F2 is more likely to bend in the Y direction.

[0076] Table 4 shows the length of the long side L2, the length of the short side S2, and the aspect ratio (L2 / S2) at each position from position Z6 to position Z11. As shown in Table 4, the length of the long side L2 and the length of the short side S2 of the filament 23 in the second region F2 gradually increase from position Z6 to position Z11 at a constant aspect ratio (1.2). In other words, the cross-sectional shapes of the filament 23 in the second region F2 are similar.

[0077]

[0078] The Z-direction lengths of the first region F1 and the second region F2 are preferably 1.5 mm or more. When the cross-sectional shapes of the filament 23 in the first region F1 and the second region F2 are similar and the Z-direction lengths are 1.5 mm or more, the first region F1 and the second region F2 have sufficient anisotropy in the directions in which they are prone to bending, allowing them to bend moderately flexibly. On the other hand, when the Z-direction lengths of the first region F1 and the second region F2 are less than 1.5 mm, the first region F1 and the second region F2 each exist in a point-like state, which may prevent them from achieving sufficient anisotropy and flexibly in the directions in which they are prone to bending.

[0079] The length of the first region F1 in the Z direction is preferably 1.5 mm or more, and more preferably 2.0 mm or more. The length of the first region F1 in the Z direction is preferably 5.5 mm or less, and more preferably 4.0 mm or less. The length of the first region F1 in the Z direction is preferably 1.5 mm or more and 5.5 mm or less, and more preferably 2.0 mm or more and 4.0 mm or less. The length of the second region F2 in the Z direction is preferably 1.5 mm or more and more preferably 2.0 mm or more. The length of the second region F2 in the Z direction is preferably 9.5 mm or less and more preferably 8.0 mm or less. The length of the second region F2 in the Z direction is preferably 1.5 mm or more and 9.5 mm or less, and more preferably 2.0 mm or more and 8.0 mm or less.

[0080] Although the present embodiment illustrates a configuration in which the aspect ratios of the first region F1 and the second region F2 are constant and the cross-sectional shapes of the filament 23 are similar, the cross-sectional shapes of the filament 23 may be identical. Preferably, the Z-direction position at which the aspect ratio is greatest in the cross section of the first region F1 is separated from the Z-direction position at which the aspect ratio is greatest in the cross section of the second region F2 by at least 1.5 mm. However, when the cross-sectional shapes of the first region F1 and the second region F2 are identical, it is sufficient that the longest distance between the Z-direction position at which the aspect ratio is greatest in the cross section of the first region F1 and the Z-direction position at which the aspect ratio is greatest in the cross section of the second region F2 is 1.5 mm or more.

[0081] In this embodiment, in addition to obtaining the same functions and effects as the first embodiment, the first region F1 and the second region F2 have sufficient anisotropy in the directions in which they are prone to bending, allowing them to bend moderately flexibly.

[0082] [Third Embodiment of Filament 23] Next, a third embodiment of the filament 23 will be described with reference to Figures 13 and 14. Figure 13 is a view of the filament 23 of the third embodiment as seen from the front side. Figure 14 is a view of the filament 23 as seen in the longitudinal direction of the handle body 10. In these figures, elements that are the same as the components of the first embodiment shown in Figures 1 to 11 are given the same reference numerals, and their description will be omitted.

[0083] 13 and 14 , the filament 23 of this embodiment has a first region F1, a second region F2, a third region F3, and a fourth region F4. When the tip position of the filament 23 in the Z direction is position Z0 and the base end position (support surface 21a) is position Z4, the first region F1 is located from position Z0 to position Z1 on the tip side of the filament 23, and the second region F2 is located from position Z2 to position Z3 on the base end side of the filament 23. The third region F3 is located from position Z1 to position Z2. The fourth region F4 is located from position Z3 to position Z4.

[0084] Table 5 shows the length of the long side, the length of the short side, and the aspect ratio (long side length) / (short side length) at each position from position Z0-Z1 to position Z4. As shown in Table 5, the first region F1 has the same long side length, short side length, aspect ratio, and cross-sectional shape over the range of positions Z0-Z1. The length of the first region F1 in the Z direction is, for example, 2 mm.

[0085]

[0086] The second region F2 has the same aspect ratio, but the lengths of the long side L2 and the short side S2 gradually increase from position Z2 to position Z3, as shown in Figure 11. The fourth region F4 has a circular cross section (aspect ratio 1:1) at position Z4. The outer contour of the cross section of the fourth region F4 gradually increases from a flat cross section with an aspect ratio of 3:2 at position Z3 to a circular cross section at position Z4.

[0087] The third region F3 is located in a range from position Z1, which is a first boundary of the first region F1 on the second region F2 side, to position Z2, which is a second boundary of the second region F2 on the first region F1 side. The third region F3 has a flat cross section. As shown in Figure 13, the third long side direction LD3 in which the long side L3 of the flat shape of the third region F3 extends gradually changes circumferentially from the same direction as the first long side direction LD1 parallel to the Y direction at position Z1 to the same direction as the second long side direction LD2 parallel to the X direction at position Z2.

[0088] That is, the filament 23 in the third region F3 is twisted about the center line J from position Z1, where the third long side direction LD3 of the cross section is the same as the first long side direction LD1 in the first region F1, to position Z2, where the third long side direction LD3 is the same as the second long side direction LD2 in the second region F2. At position Z1, the length of the long side L3 of the third region F3 is the same as the length of the long side L1 in the first region F1, and the length of the short side S3 of the third region F3 is the same as the length of the short side S1 in the first region F1. At position Z2, the length of the long side L3 of the third region F3 is the same as the length of the long side L2 in the second region F2, and the length of the short side S3 of the third region F3 is the same as the length of the short side S2 in the second region F2. Therefore, the third long side direction LD3, the length of the long side L3, and the length of the short side S3 of the filament 23 in the third region F3 gradually change in the circumferential direction from position Z1 to position Z2.

[0089] In this embodiment, in addition to obtaining the same functions and effects as those of the first embodiment, the third long side direction LD3 of the filament 23 in the third region F3 changes continuously in the circumferential direction, which makes it possible for the entire filament 23 to bend in various directions depending on how the brushing load is applied and how the brush is moved.

[0090] 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.

[0091] For example, in the above embodiment, a configuration in which a third region F3 serving as a neutral region is provided between the first region F1 and the second region F2 has been exemplified, but this configuration is not limited thereto. A configuration in which the first region F1 and the second region F2 are adjacent to each other in the Z direction without providing the third region F3 serving as a neutral region between the first region F1 and the second region F2 may be adopted. In this configuration, the outer shapes of the first region F1 and the second region F2 may be continuously connected, or a step may be formed at the connection between the first region F1 and the second region F2. Furthermore, the tip side of the filament 23 may be branched into two or more. In the case of a branched filament, each region may be the same or different. Furthermore, the branched portions may have different lengths in the longitudinal direction.

[0092] Furthermore, in the above embodiment, the toothbrush 1 is configured by the brush molded body 20 and the handle body 10, which are molded separately, and the brush molded body 20 is attached to the handle body 10 by fitting the fitting protrusion 12 of the handle body 10 into the fitting hole 22 of the brush molded body 20. However, this configuration is not limited to this. For example, the handle body 10 may be molded by primary molding using a first mold, and then the brush molded body 20 may be insert-molded by secondary molding using a second mold in which the fitting protrusion 12 of the handle body 10 is installed. This insert molding allows the fitting protrusion 12 to fit into the fitting hole 22, thereby obtaining the toothbrush 1 as a molded body in which the brush molded body 20 and the handle body 10 that supports the brush molded body 20 are integrally molded. The molded body in which the brush molded body 20 and the handle body 10 that supports the brush molded body 20 are integrally molded is not limited to a configuration in which the fitting protrusion 12 of the handle body 10 fits into the fitting hole 22 of the brush molded body 20. For example, the handle body may be made of hard resin and have a head portion with a through hole formed in the thickness direction, and soft resin may be filled in through the through hole from the back side to form a molded body in which the head base portion and filament are integrally molded.

[0093] In the above embodiment, the handle body 10 is formed from a hard resin, but the present invention is not limited to this configuration, and for example, a part of the handle body 10 (such as the handle portion 11) may be covered with a soft resin. This configuration can improve decorativeness and gripping properties.

[0094] The present invention is applicable to brush moldings and toothbrushes.

[0095] REFERENCE SIGNS LIST 1...toothbrush, 10...handle body, 12...fitting protrusion, 20...brush molding, 21...head base portion, 21a...support surface, 22...fitting hole, 23...filament, F1...first region, F2...second region, F3...third region, J...center line, L1, L2, L3...long sides, LD1...first long side direction, LD2...second long side direction, LD3...third long side direction, S1, S2...short sides, Z1...position (first boundary), Z2...position (second boundary)

Claims

DEPCT671. A brush molding device which has a base head molded of soft resin and a number of bristles extended in the longitudinal direction from a support located on the front side of the thickness direction of the said base head. Such bristles have one region where the flat cross-section is perpendicular to the said longitudinal direction, and a second region where the flat cross-section is perpendicular to the said longitudinal direction, the position of the said longitudinal direction differs from that of the first region, the first longitudinal direction of which the flat cross-section in the first region is constant in that region, and the second longitudinal direction of which the flat cross-section in the second region is constant in that region, and such longitudinal directions first and second intersect when viewed in the said longitudinal direction.

2. A brush molding device specified in Representation 1 in which, among the angles at which such longitudinal directions first and second intersect, the smaller angle is equal to 60 degrees or more. 3.

4. The brush former specified in Reputation 1 or 2, where the first region is located at the distal end of the said longitudinal direction greater than the second region, and the said longitudinal side in the first region is a segment of the line formed in the longitudinal direction of the head base perpendicular to the said thickness direction.

5. The brush former specified in Reputation 1 or 2, where the cross-sectional shape in the first and second regions varies or is fixed in the same shape, respectively, and the length in the said longitudinal direction of the first and second regions is 1.5 mm or greater, respectively.Any one of the brush forming devices specified in Requisitions 1 to 2, where the maximum length of such long side in the second region is designated as W(B), and where the length of such short side in the long axis direction, where such long side in the second region has the maximum length, is designated as D(B), and where the bending coefficient in the second long side direction at the cross-section in the second region is designated as DW3(B), and where the bending coefficient in the second short side direction perpendicular to the second long side direction at the cross-section in the second region is designated as WD3(B), and the value expressed as DW3(B) / WD3(B) is greater than or equal to 1.4 and less than or equal to 4.0, The maximum length of the long side in the first region is given as W(A), and the length of the short side in the long axis direction, which has a maximum length in the first region, is given as D(A), and the bending coefficient in the first long side direction at the cross-section in the first region is given as DW3(A), and the bending coefficient in the first short side direction perpendicular to the first long side direction at the cross-section in the first region is given as WD3(A), and the values ​​expressed as DW3(A) / WD3(A) are greater than or equal to 1.4 and less than or equal to 9.

06. The brush forming agent specified in claim 5, where the values ​​expressed as WD3(B) / WD3(A) are greater than or equal to 4.0 and less than or equal to 80.0 and 7.The brush former specified in Reputation 1 or 2, where in the cross-section in the second region, the position of the longitudinal direction at its greatest magnitude is within the range of positions where the length in the longitudinal direction of the bristles is equal to 75% from the support to the support, and where in the cross-section in the first region, the position of the longitudinal direction at its greatest magnitude is within the range of positions where the length in the longitudinal direction of the bristles is equal to 50% from the support to the bristle tip.

8. The brush former specified in Reputation 1 or 2, where the bristles comprise an area with a 1:1 magnitude ratio in the cross-section between the first and second regions. 9.

10. A toothbrush whose brush forming body is specified in Reputation 1 or 2, in which the bristles have a third longitudinal region extending from the first boundary of the second longitudinal region in the said first region to the second boundary of the first region in the said second region and the third longitudinal region, in which the third longitudinal region gradually varies in a circumferential direction with a centerline extended in the said longitudinal direction centered from the same direction as the first longitudinal direction at the said first boundary to the same direction as the second longitudinal direction at the said second boundary.

10. A toothbrush whose brush forming body is specified in Reputation 1 or 2, in which the base of the head has a joint hole extended in a length direction perpendicular to the thickness direction and opens on one side in the said length direction, and is characterized by being incorporated with a handle molded in hard resin and having a joint pin that fits into the joint hole. 11.A toothbrush which has a brush molding body as specified in claim 1 or 2, in which a handle is molded from a hard resin and supports such brush molding body, and which is characterized by the brush molding body and handle being molded as a single piece;

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