JP2023026518A - toothbrush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toothbrush having a thin head which provides excellent operability.

SOLUTION: The thickness of a head part is 2.0 to 4.0 mm. A minimum value of the width of a neck part is 3.5 mm or more and 4.5 mm or less. A value calculated by D/W at a position 10 mm away from an original point toward a rear end side is 0.7 or more and 2.5 or less. A value calculated by D/W at a position 20 mm away toward the rear end side is 1.2 or less, and W×D³ is 350 mm⁴ or more and 550 mm⁴ or less. A rate of change of the value calculated by D/W from the position 10 mm away from the original point toward the rear end side to the position 20 mm away is more than 1.0. A rate of change of the value calculated by D/W from the position 20 mm away from the original point toward the rear end side to a position 30 mm away is more than 1.0. W×D³ at the position 10 mm away from the original point toward the rear end side is 165 mm⁴ or more and 310 mm⁴ or less, and W×D³ at the position 30 mm away is 600 mm⁴ or more and 1500 mm⁴ or less.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to toothbrushes.
This application claims priority based on Japanese Patent Application No. 2016-211879 filed in Japan on October 28, 2016, the content of which is incorporated herein.

Patent Documents 1 to 3 propose a toothbrush with a thin head from the viewpoint of operability in the oral cavity. Reducing the thickness of the head poses problems such as a decrease in strength. Therefore, a high-strength resin such as polyacetal resin (POM) is used. In particular, in the case of flat wire flocking in which a flat metal wire is driven into a resin head to hold the brush, the flocking strength and the folding endurance of the head may be insufficient.

JP-A-7-143914 Japanese Patent Application Laid-Open No. 2011-4852 Japanese Unexamined Patent Application Publication No. 2011-200296

The inventors of the present invention have found that in the toothbrush described above, if the neck portion connecting the head portion and the handle portion is thick, the effect of improving the operability in the oral cavity due to the thin head portion is impaired. served. In particular, if the neck is widened, the operability is further impaired, and the thinness of the head is not conspicuous in terms of appearance, impairing the impression of the product. However, if the neck portion is made thin, the operability may be adversely affected due to excessive bending. In addition, further improvement is required in terms of strength. In the case of general-purpose resins, such as polypropylene (PP), which are commonly used in toothbrushes, the problem is more pronounced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a toothbrush with a thin head that is easy to operate.

According to the first aspect of the present invention, a head portion arranged on the tip side and having a hair bundle implanted on the hair-implanted surface, a neck portion extending to the rear end side of the head portion, and the neck portion a handle portion extending to the rear end side, the head portion having a thickness of 2.0 to 4.0 mm, and the neck portion being parallel to the flocking surface and having the same length as the handle portion. The minimum value of the width in the direction perpendicular to the direction is 3.5 mm or more and 4.5 mm or less, and the width is constant or gradually increases toward the rear end from the minimum value position, and the neck portion When the width of the neck portion is Wmm and the thickness in the direction orthogonal to the flocked surface is Dmm, the width of the neck portion becomes the minimum value when the width gradually increases toward the rear end side from the minimum value position. When the width of the neck portion is constant from the position where the minimum value is the minimum value to the rear end side, the position of the minimum value on the most distal side is the starting point, and the width is parallel to the flocking surface and toward the rear end side The value obtained by D/W at a position 10 mm away is 0.7 or more and 2.5 or less, and the value obtained by D/W at a position 20 mm away from the position of the starting point toward the rear end is 1.2 or less, and a deflection coefficient M (mm ⁴ ) at a position 20 mm away from the position of the starting point to the rear end side = W × D ³ is 350 mm ⁴ or more and 550 mm ⁴ or less, and the position of the starting point From the position 10 mm away from the rear end side to the position 20 mm away from the position of the starting point to the rear end side, the rate of change in the value obtained by D / W exceeds 1.0, and the position of the starting point From the position 20 mm away from the rear end side to the position 30 mm away from the position of the starting point to the rear end side, the rate of change in the value obtained by D / W exceeds 1.0, and the position of the starting point is 165 mm ^{4 or} more and 310 mm ⁴ or less ^at a position 10 mm away from the starting point to the rear end side, and at a position 30 mm away from the starting point to the rear end side A toothbrush is provided in which a bending modulus M (mm ⁴ )=W×D ³ is 600 mm ⁴ or more and 1500 mm ⁴ or less.

Further, in the toothbrush according to the aspect of the present invention, the value obtained by D / W at a position 30 mm away from the position of the starting point toward the rear end is more than 1.0 and 1.3 or less. characterized by being

Further, in the toothbrush according to the aspect of the present invention, the W × D ³ at a position 30 mm away from the starting point to the rear end side from a position 20 mm away from the starting point to the rear end side. A change rate of the bending coefficient M (mm ⁴ ) to be obtained is characterized by being 1.8 or more and 3.0 or less.

Further, in the toothbrush according to the aspect of the present invention, the deflection coefficient M (mm ⁴ ) obtained by W × D ³ at a position 10 mm away from the position of the starting point to the rear end side from the position of the starting point is 1.0 or more and 1.3 or less.

Further, in the toothbrush according to one aspect of the present invention, the length of the head portion in the longitudinal direction is 10 mm or more and 33 mm or less.

Further, in the toothbrush according to one aspect of the present invention, the length of the neck portion in the longitudinal direction is 25 mm or more and 70 mm or less.

Further, in the toothbrush according to one aspect of the present invention, the material of the handle body including the head portion, the neck portion and the handle portion is polypropylene resin, polyacetal resin, polystyrene resin, polyethylene terephthalate resin, polybutylene terephthalate resin, It is characterized by being one of acrylonitrile-butadiene-styrene resin, polyarylate resin, polycarbonate resin, and acrylonitrile-styrene resin.

Further, in the toothbrush according to the aspect of the present invention, the tufts of bristles are implanted in the head portion using a flat wire.

INDUSTRIAL APPLICABILITY In the present invention, it is possible to provide a toothbrush that provides good intraoral operability even when a general-purpose resin is used.

1 is a plan view of a toothbrush 11, showing an embodiment of the present invention. FIG. It is a side view of the same toothbrush 11. FIG. 2 is an enlarged plan view of the tip side of the toothbrush 11. FIG. Fig. 3 is a side view showing an enlarged tip side of the toothbrush 11;

Embodiments of a toothbrush handle and a toothbrush according to the present invention will be described below with reference to FIGS. 1 to 4. FIG.
The following embodiment shows one aspect of the present invention, does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. Also, in the drawings below, in order to make each configuration easier to understand, the actual structure and each structure are different in scale, number, and the like.

FIG. 1 is a plan view of the toothbrush 11. FIG. FIG. 2 is a side view of the toothbrush 11. FIG. FIG. 3 is an enlarged plan view of the tip side of the toothbrush 11. FIG. FIG. 4 is an enlarged side view of the tip side of the toothbrush 11. FIG.

The toothbrush 11 of this embodiment includes a head portion 110 arranged at the tip and implanted with a bristle bundle 114, a neck portion 120 extending from the rear end side of the head portion 110, and a rear end of the neck portion 120. A handle portion 130 (hereinafter, the head portion 110, the neck portion 120, and the handle portion 130 are collectively referred to as a handle body 12) is provided.

The handle body is integrally molded in a long shape as a whole, and is obtained, for example, by injection molding using resin as a material.
Examples of the material of the handle body include resins having a bending elastic modulus (JIS7171) of 1000 MPa or more and 2200 MPa or less. ), polybutylene terephthalate resin (PBT), acrylonitrile-butadiene-styrene resin (ABS), polyarylate resin, polycarbonate resin, acrylonitrile-styrene resin (AS), and the like. Among these resins, polypropylene resin, which is a general-purpose resin, is preferable in view of the fact that the effect of the present invention is more remarkable and the aspect of cost.

One of the above resins may be used alone, or two or more of them may be used in combination.
Moreover, the handle body may be partially or wholly coated with a flexible resin such as an elastomer, for example, in order to improve gripability. When using a flexible resin such as an elastomer, for example, polyolefin is preferable, and PP is more preferable, from the viewpoint of enhancing adhesiveness.

The head portion 110 has a flocked surface 111 on one side in the thickness direction (hereinafter referred to as the upper surface side). A plurality of tufting holes 112 are formed in the tufting surface 111 , and tufts 114 (see FIG. 2 ) of hair are planted in the tufting holes 112 . 1, 3 and 4, illustration of the hair bundle 114 is omitted.

The rear end of the head portion 110 in the present embodiment is arranged on the rearmost side when the distance from the outer edge of the tufting hole 112 arranged on the frontmost side to the front end of the head portion 110 is L11. It is defined at the position of the distance L11 from the outer edge of the tufting hole 112 to the rear end side. That is, as shown in FIG. 3, the head portion 110 is arranged in a range 110A separated by a distance L11 from the outer edges of the tufting holes 112 positioned at both ends in the length direction. A position on the rear end side of the range 110A is the boundary between the head portion 110 and the neck portion 120 .

The tip end of the handle portion 130 serves as a finger rest, and the tip end of the finger rest serves as a boundary between the neck portion 120 and the handle portion 130 . The finger rest portion is, for example, a ridgeline formed at the intersection of a surface on the rear end side of the neck portion 120 on the side of the flocked surface 111 and a surface on the side of the flocked surface 111 on the tip side of the handle portion 130, or a neck portion. It is partitioned by a ridge line formed at the intersection of the surface opposite to the flocked surface 111 on the rear end side of 120 and the surface opposite to the flocked surface 111 on the distal end side of the handle portion 130 . In this case, the boundary between neck portion 120 and handle portion 130 is defined by the ridge.

Further, when the surface of the rear end of the neck portion 120 facing the flocking surface 111 and the surface of the front end of the handle portion facing the flocking surface 111 are flush with each other and do not form a ridgeline, the rear end of the neck portion 120 The finger rest section is defined by a ridge line formed at the intersection of the widthwise side surface of and the widthwise side surface of the tip end of the handle portion 130 . Again, the boundary between the neck portion 120 and the handle portion 130 is defined by the ridgeline.

For example, when viewed from the side, the handle portion 130 is formed in a generally arcuate shape that protrudes toward the flocking surface 111 side, and the neck portion 120 is formed in a generally arcuate shape that is concave toward the flocking surface 111 side. For handle body 12, the boundary between neck portion 120 and handle portion 130 is defined as follows.

On the side of the flocked surface 111 on the tip side of the handle portion 130, the center position is arranged on the side opposite to the flocked surface 111 (lower than the handle portion 130 in FIGS. 2 and 4), and the flocked surface 111 side is located on the side view. A curved surface 133 having a convex arc contour is formed. Similarly, on the side opposite to the flocked surface 111 on the distal end side of the handle portion 130, a curved surface 134 with an arc contour is formed, the center position of which is located on the side opposite to the flocked surface 111, and which is convex on the flocked surface 111 side when viewed from the side. It is

In addition, on the side of the flocked surface 111 on the rear end side of the neck portion 120, the center position is arranged on the flocked surface 111 (above the handle portion 130 in FIGS. 2 and 4), and the flocked surface 111 side is concave when viewed from the side. A curved surface 123 having an arc contour is formed. Similarly, on the rear end side of the neck portion 120 on the side opposite to the flocked surface 111, there is formed a curved surface 124 with an arc contour whose center position is located on the flocked surface 111 and which is concave on the flocked surface 111 side when viewed from the side. .

As the curved surface 123 and the curved surface 133 progress in the length direction of the handle portion 130, the intersection angle between the tangent line in the side view and the flocking surface 111 continuously changes. intersect at an angle θ1 that is not 0 or 180 degrees between tangents. Therefore, a ridgeline 131 is formed at the intersection of the curved surface 123 and the curved surface 133 .

Regarding the curved surface 124 and the curved surface 134 as well, the angle of intersection between the tangential line in the side view and the flocked surface 111 changes continuously as the handle portion 130 progresses in the length direction. , the tangent lines intersect at an angle θ2 that is not 0 or 180 degrees. Therefore, a ridgeline 132 is formed at the intersection of the curved surfaces 124 and 134 . Therefore, the neck portion 120 and the handle portion 130 have arc-shaped curved surfaces 133 and 134 that are convex on the flocking surface 111 side in a side view on one side in the length direction sandwiching the ridgelines 131 and 132 . The other side in the length direction is connected to curved surfaces 123 and 124 having an arc contour with the flocked surface 111 side being concave in side view, thereby forming a substantially S-shape in side view.

The boundary on the rear end side of neck portion 120 is defined by ridgelines 131 and 132 . Therefore, the rear end side of the ridgelines 131 and 132 is a range 130A in which the handle portion 130 is arranged, and is between the range 110A in which the head portion 110 is arranged and the range 130A in which the handle portion 130 is arranged. The neck portion 120 is arranged in the range 120A of .

The end of the handle portion 130 on the flocking surface 111 side (the rear end side of the ridgeline 131) serves as a finger rest portion. The user can stably operate the toothbrush 11 by holding the handle portion 130 with the thumb on the finger rest portion. In addition, the position of the ridge line 132 in the length direction of the handle portion 130 is on the rear end side of the ridge line 131 . Therefore, compared with the case where the ridgeline 132 is located on the front end side of the ridgeline 131, the finger rest portion is thicker, and the operation of the toothbrush 11 can be further stabilized.

The length of the handle body 12 is not particularly limited, and is, for example, 100-200 mm.
The width of the head portion 110, that is, the width in the direction parallel to the flocking surface 111 and perpendicular to the length direction of the handle portion 130 (hereinafter simply referred to as width) is not particularly limited, and is preferably 5 to 16 mm, for example. , 8 to 12 mm. If it is at least the above lower limit value, a sufficient area for planting the hair bundle 114 can be secured, and if it is at most the above upper limit value, the operability in the oral cavity can be further enhanced.
The length of the head portion 110 is not particularly limited, and is preferably 10 to 33 mm, more preferably 12 to 28 mm, for example. If it is at least the above lower limit value, a sufficient area for planting the hair bundle 114 can be secured, and if it is at most the above upper limit value, the operability in the oral cavity can be further enhanced.
The thickness of the head portion 110 can be determined in consideration of the material and the like, and is preferably 2.0 to 4.0 mm, for example. If it is at least the above lower limit value, the strength of the head portion 110 can be further enhanced, and if it is at most the above upper limit value, the reachability to molars can be enhanced, and the operability in the oral cavity can be further enhanced.

The length of the neck portion 120 is preferably 25 to 70 mm, for example, so that the neck portion 120 touches the lips when the head portion 110 is inserted into the oral cavity.
The width of the neck portion 120 is formed so as to be constant or gradually increase toward the rear end side from the minimum value position. When the width of the neck portion 120 is constant from the position of the minimum value to the rear end side, the position of the minimum value is defined as the most distal position. The neck portion 120 in this embodiment is formed so that the width gradually increases from a position 121 where the width is the minimum value toward the rear end side. The width of the neck portion 120 can be determined in consideration of the material, etc. For example, the minimum width of the neck portion 120 is preferably 3.5 mm or more and 4.5 mm or less, more preferably 3.7 mm or more and 4.3 mm or less. If it is at least the above lower limit value, the strength of the neck portion 120 can be further increased, and if it is at most the above upper limit value, the lip can be easily closed, the accessibility to the molars can be improved, and the operability in the oral cavity can be further improved. Increased.

Further, if the width of the neck portion 120 is W mm, and the thickness in the direction perpendicular to the flocking surface 111 is D mm, the width of the neck portion 120 is set to the minimum value 121 as a starting point and extends parallel to the flocking surface 111 toward the rear end side. The value obtained by D/W at the position 122 separated by 10 mm is preferably 0.7 or more and 2.5 or less, more preferably 0.7 or more and 2.0 or less, and 0.8 or more. , is more preferably 2.0 or less, and particularly preferably 0.8 or more and 1.5 or less.

When the minimum width of the neck portion 120 is 3.5 mm or more and 4.5 mm or less, and the value obtained by D/W is less than the above lower limit value, the neck portion 120 tends to flex during brushing, making it difficult to operate. In addition, the wide neck portion 120 impairs operability, and the thinness of the head portion 110 is not conspicuous in terms of appearance, and the impression of the product may be spoiled.
On the other hand, when the value obtained by D/W exceeds the above upper limit, the thickness D increases, and it may become difficult to close the lips when brushing the occlusal surface. In addition, the effect of improving operability obtained by making the head portion 110 thin may be impaired. Therefore, if the value obtained by D/W is 0.7 or more and 2.5 or less, it becomes easier to close the lips and brush while maintaining the improvement in operability obtained by thinning the head portion 110 .

In addition, the value obtained by D/W at a position 20 mm away from the position 121 where the width of the neck portion 120 is the minimum value is preferably more than 1.0 and 1.3 or less. , 1.05 or more and 1.2 or less. Similarly, the value obtained by D/W at a position 30 mm away from the position 121 where the width of the neck portion 120 is the minimum value is more than 1.0 and less than or equal to 1.5. It is preferably 1.05 or more and 1.3 or less.

By making the thickness D larger than the width W at a position 20 mm away from the position 121 where the width of the neck portion 120 is the minimum value to the rear end side, the neck portion 120 becomes easy to bend, thereby improving the operability. In addition, it is possible to prevent the neck portion 120 from widening and impairing the operability. As described above, if the value obtained by D/W at the position is within the above range, even when the position of the neck portion 120 is inserted into the oral cavity, it is difficult to close the lips and the effect of improving the operability can be obtained. can be secured. If the value obtained by D/W at the position 30 mm away from the rear end side from the position 121 where the width is the minimum value is within the above range, it is possible to improve operability without considering that it becomes difficult to close the lips. Effectiveness can be ensured.

Further, the difference between the value obtained by D/W at position 121 and the value obtained by D/W at a position 20 mm away from the position 121 toward the rear end is 0.05 or more and 0.07. is preferably 0.06 or more and 0.07 or less. If the difference between the values obtained by D/W is less than the lower limit and exceeds the upper limit, if the value obtained by D/W is less than the lower limit and the value obtained by D/W is There is a possibility of causing the same problem as when the above upper limit is exceeded. Therefore, the difference between the value obtained by the D/W at the position 121 and the value obtained by the D/W at a position 20 mm away from the position 121 to the rear end side is 0.05 or more and 0.07 or less. In this case, it becomes easier to close the lips and brush while maintaining the improved operability obtained by making the head portion 110 thin.
In addition, the value obtained by the D / W at a position 30 mm away from the position 121 to the rear end side is larger than the value obtained by the D / W at the position 121, and the difference is 0.1 or more, 0 .2 or less. If the value obtained by the above D/W at a position 30 mm away from the position 121 to the rear end side and the value obtained by the above D/W at the position 121 satisfy the above relationship, the head portion 110 is thinned. While maintaining the improved operability obtained by doing so, it becomes easier to close the lips and brush.

Regarding the change rate of D/W at the position on the rear end side with respect to the position on the front end side in the length direction of the handle portion 130, the width from the position 121 where the width of the neck portion 120 is the minimum value to the rear end side Assuming that the rate of change of D/W at a position 10 mm away from the center is R01, the rate of change R01 is preferably more than 1.00 and less than or equal to 1.2. Assuming that the rate of change in D/W at a position 20 mm away from the position 121 toward the rear end is R02, the rate of change R02 is preferably more than 1.00 and less than or equal to 1.2. Assuming that the rate of change in D/W at a position 30 mm away from the position 121 toward the rear end is R03, the rate of change R03 is preferably more than 1.00 and less than or equal to 1.3. The rates of change R01, R02 and R03 preferably satisfy the relationship R01<R02<R03.
As a result, it is possible to avoid difficulty in brushing due to closed lips due to the already large thickness D on the tip side of the neck portion 120 where it is easier to enter the oral cavity. In addition, by changing the thickness D more greatly on the rear end side of the neck portion 120 where the load due to brushing is likely to be applied, it is possible to avoid operability problems caused by excessive bending in the direction of the thickness D. .

Further, if the rate of change in D/W at a position 20 mm away from the position 121 to the rear end side from the position 121 as the starting point is R12, the rate of change R12 is 1.0 mm. 00 and preferably 1.2 or less. Let R23 be the change rate of D/W at a position 20 mm away from the position 121 toward the rear end and 30 mm away toward the rear end from the position 121 as the starting point. It is preferable that it exceeds and is 1.3 or less. The rates of change R12 and R23 preferably satisfy the relationship R01≤R12≤R23. In addition, at least one of the rate of change R12 and R23 is preferably greater than the rate of change R01.
As a result, in the same manner as described above, it is possible to avoid difficulty in brushing due to closed lips due to the already large thickness D on the tip side of the neck portion 120 where it is easier to enter the oral cavity. In addition, by changing the thickness D more greatly on the rear end side of the neck portion 120 where the load due to brushing is likely to be applied, it is possible to avoid operability problems caused by excessive bending in the direction of the thickness D. .

In addition, it is generally known that when the material is the same, the amount of deflection of a rigid body is greatly affected by the "geometrical moment of inertia". Since the amount of deflection is proportional to the first power of the width W and the cube of the thickness D, it is desirable to minimize the width while maintaining the thickness D in order to reduce the amount of deflection.
For example, if the flexural modulus M (mm ⁴ )=W×D ³ , the flexural modulus M calculated from the width W and the thickness D at the position 121 of the neck portion 120 is 165 mm ⁴ or more and 625 mm ⁴ or less. It is preferably 180 mm ⁴ or more and 525 mm ⁴ or less, and particularly preferably 200 mm ⁴ or more and 330 mm ⁴ or less. Further, the deflection coefficient M calculated from the width W and the thickness D at the position 122 of the neck portion 120 is 165 mm ⁴ or more and 625 mm ⁴ or less, more preferably 180 mm ⁴ or more and 525 mm ⁴ or less, and 200 mm ⁴ . Above, it is more preferably 330 mm ⁴ or less, and more preferably 270 mm ⁴ or more and 310 mm ⁴ or less. At a position 20 mm away from the position 121 to the rear end side parallel to the flocking surface 111, the deflection coefficient M calculated from the width W and the thickness D of the neck portion 120 is preferably 350 mm ⁴ or more and 550 mm ⁴ or less. . At a position 30 mm away from the position 121 in parallel with the flocking surface 111 toward the rear end side, the deflection coefficient M calculated from the width W and the thickness D of the neck portion 120 is preferably 600 mm ⁴ or more and 1500 mm ⁴ or less. .
If the deflection coefficient M at the position 122 is 165 mm ⁴ or more and 625 mm ⁴ or less, it is possible to contribute to the improvement of brushing performance with closed lips and to prevent deterioration of operability due to excessive deflection.

The rate of change of the bending coefficient M is preferably 1.0 or more and 1.3 or less between the positions 121 and 122 . Moreover, the rate of change of the deflection coefficient M between the position 122 and the position 20 mm away from the position 121 to the rear end side is preferably 1.3 or more and 1.8 or less. The rate of change of the deflection coefficient M between the position 20 mm away from the position 121 to the rear end side and the position 30 mm away from the position 121 to the rear end side is 1.7 or more and 3.0 or less. It is preferably 1.8 or more and 3.0 or less. The rate of change is a value obtained by dividing the flexural coefficient at the position on the rear end side by the flexural coefficient at the position on the distal end side. is a value calculated as M/M from
If the deflection coefficient M and its rate of change are within the above ranges, it becomes easier to close the lips and brush without deteriorating operability.

The hair bundle 114 is a bundle of a plurality of hairs. The length (hair length) from the hair-implanted surface 111 to the tip of the hair bundle 114 can be determined in consideration of the desired hair stiffness of the hair bundle 114, and is, for example, 6 to 13 mm. All hair tresses 114 may have the same hair length, or may be different from each other.

The thickness (bundle diameter) of the hair bundle 114 can be determined in consideration of the hair stiffness required for the hair bundle 114, and is set to 1 to 3 mm, for example. All tufts 114 may have the same tuft diameter, or may differ from each other.

The bristles that make up the tuft 114 include, for example, bristles (tapered bristles) whose diameter gradually decreases toward the tip and whose tip is sharpened (tapered bristles), and whose diameter increases from the flocked surface 111 toward the tip of the bristle. Almost identical hair (straight hair) and the like can be mentioned. Examples of straight bristles include bristles having a flat surface substantially parallel to the flocking surface 111 and bristles having bristles rounded into a hemispherical shape.

Materials of bristles include, for example, polyamides such as 6-12 nylon (6-12NY) and 6-10 nylon (6-10NY), PET, PBT, polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), Elastomer resins such as polyesters such as polybutylene naphthalate (PBN), polyolefins such as PP, polyolefin elastomers, and styrene elastomers can be used. These resin materials can be used individually by 1 type or in combination of 2 or more types. Examples of bristles include polyester bristles having a multi-core structure having a core and at least one layer of sheath provided outside the core.

The cross-sectional shape of the bristles is not particularly limited, and may be a circle such as a perfect circle or an oval, a polygon, a star, a three-leaf clover, a four-leaf clover, or the like. The cross-sectional shape of all bristles may be the same or may be different.

The thickness of the bristles can be determined in consideration of the material and the like, and when the cross section is circular, it is, for example, 6 to 9 mil (1 mil=1/1000 inch=0.025 mm). In addition, a plurality of bristles having different thicknesses may be arbitrarily combined in consideration of usability, cleaning feeling, cleaning effect, durability, and the like.

In the method of manufacturing the toothbrush 11, first, the handle body 12 is molded by injection molding.
Next, hair bundles 114 are implanted in the head portion 110 of the obtained handle body 12 . The hair bundle 114 may be implanted by folding the hair bundle 114 in two and driving a flat wire sandwiched between them into the tufting hole 112 to implant the hair bundle 114. The lower end of the hair bundle 114 is implanted. A heat-sealing method in which the bristle bundle 114 is pressed into the molten resin to be fixed and fixed, and an in-mold method in which the bristle bundle 114 is heated at the lower end to form a molten mass, and then the molten resin is injected into the mold to form the bristle-implanted portion. etc.

As described above, according to the toothbrush 11 of the present embodiment, the minimum width of the neck portion 120 is 3.5 mm or more and 4.5 mm or less, thereby ensuring a state in which the lips are closed to facilitate brushing. , D / W is 0.7 or more and 2.5, so that the deterioration of operability can be avoided even when using general-purpose resins such as polypropylene as well as engineering plastics such as polyacetal. becomes possible.

In the case of flat wire type flocking, stress is applied to the head portion 110 due to flat wire implantation. When the head portion 110 is thin and has low strength against deformation when force is applied, while the neck portion 120 is thick and strong, the stress during brushing the teeth concentrates on the head portion 110, and the head portion 110 warps greatly. It may become difficult to use. On the other hand, according to the toothbrush 11 of the present embodiment, the neck portion 120 is made thin and has a certain degree of flexibility, so that the stress caused when brushing teeth can be distributed from the head portion 110 to the entire neck portion 120. , usability is improved. Therefore, the effects of the present invention can be particularly remarkably obtained in the case of flat-line flocking.

[Example]
EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples, and can be carried out with appropriate modifications within the scope of the invention.

(Examples 1 to 5, Comparative Examples 1 to 7)
Toothbrushes of Examples 1 to 1 and Comparative Examples 1 to 7 were manufactured in which the neck portion 120 was formed according to the specifications shown in [Table 1] above. The width, length, thickness and shape of the head portion and the handle portion were all the same. PP resin was injection molded to obtain an integrally molded product of the head portion and the handle body shown in FIGS. , 4 holes x 6 rows, 3 holes x 1 row, head width 10 mm, length 25 mm, thickness 3.0 mm, handle length 110 mm, neck length 48 mm). A tuft of taper bristles (7.5 mil) made of PBT filaments was implanted in the head portion by flat wire implantation to prepare a toothbrush.

The value obtained by D/W at the position where the width of the neck portion is the smallest in each example, the position of 10 mm, 20 mm, and 30 mm on the rear end side from the minimum position, and the value obtained by W × D ³ are shown in [Table 2]. Also, the rate of change of the value obtained by W×D ³ in each example, calculated from the deflection coefficient at each position as described above, is shown in [Table 3]. Also, the change rate of the value obtained by D/W in each example is shown in [Table 4].

(Evaluation method)
The toothbrush of each example was evaluated for "intraoral operability (ease of movement in the mouth) of the toothbrush" by the following method.
<Toothbrush operability>
For the operability of the toothbrush, 10 expert panelists used the toothbrush of each case and evaluated the "intraoral operability" according to the following evaluation criteria. An average score of 2.5 points or more from the 10 specialized panels is marked with "◎", an average score of 2.0 or more and less than 2.5 points is marked with "○", and an average score of 1.5 or more and less than 2.0 points is marked with " △”, and an average score of less than 1.5 was indicated as “x”.

≪Evaluation Criteria≫
3 points: Very easy to move in the mouth.
2 points: Ease of movement in the mouth is felt.
1 point: I do not feel the easiness of movement in the mouth.
0 point: No sense of ease of movement in the mouth.

As shown in Table 2, the thickness of the head portion is 2.0 to 4.0 mm, and the minimum width of the neck portion is 3.5 mm or more and 4.5 mm or less, which is the minimum value of the neck portion. The value obtained by D / W at a position 10 mm away from the position to the rear end side is 0.7 or more and 2.5 or less, and the value obtained by D / W at the position 121 where the width is the minimum value , the difference from the value obtained by D/W at a position 20 mm away from the position 121 to the rear end side is 0.05 or more, and the deflection coefficient M (mm ⁴ ) = W × D ³ is 165 mm ⁴ or more, 625 mm ⁴ or less, the value obtained by D / W at the position 20 mm away from the position 121 to the rear end side exceeds 1.0, and the value obtained by D / W at the position 30 mm away from the position 121 to the rear end side is greater than the value obtained by D/W at position 121, and the difference between them is 0.1 or more.

Further, as shown in Table 4, when the rate of change R01, R02, R03, R12, R13 each exceeds 1.00 and further satisfies the relationship of R01<R02<R03 and the relationship of R01≦R12≦R23 It was also confirmed that good operability was obtained.

Although 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 such examples. The various shapes, combinations, etc., of the constituent members shown in the above examples are merely examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

For example, in the toothbrush 11 of the above-described embodiment, the configuration in which the width gradually increases from the position where the neck portion 120 is the minimum width toward the rear end side is illustrated, but the configuration is not limited to this configuration, and the width is the same on the rear end side. It may be a configuration extending to. Even if the neck portion 120 has the same width and extends toward the rear end, the value obtained by D/W at a position 10 mm away from the minimum width position toward the rear end is 0.7 or more and 2.5 or less. Preferably.

DESCRIPTION OF SYMBOLS 11... Toothbrush 12... Handle body 110... Head part 111... Flocking surface 120... Neck part 130... Handle part

Claims (8)

a head part arranged on the tip side and having a hair bundle planted on the hair planting surface;
a neck portion extending from the rear end side of the head portion;
a handle portion extending from the rear end side of the neck portion,
The head portion has a thickness of 2.0 to 4.0 mm,
The neck portion has a minimum width of 3.5 mm or more and 4.5 mm or less in a direction parallel to the flocking surface and perpendicular to the length direction of the handle portion, and formed so that the width is constant or gradually increases on the rear end side,
Assuming that the width of the neck portion is W mm and the thickness in the direction perpendicular to the flocking surface is D mm,
When the width of the neck portion gradually increases toward the rear end side from the position where the width of the neck portion becomes the minimum value, the position where the width of the neck portion becomes the minimum value is used as a starting point, and the width of the neck portion becomes the minimum value. When constant on the end side, the value obtained by D/W at a position 10 mm away from the rear end side in parallel with the flocking surface is 0.7 or more, starting from the position of the minimum value closest to the tip side. 2.5 or less,
The value obtained by D/W at a position 20 mm away from the position of the starting point toward the rear end is 1.2 or less,
A deflection coefficient M (mm ⁴ )=W×D ³ at a position 20 mm away from the starting point to the rear end side is 350 mm ⁴ or more and 550 mm ⁴ or less,
A rate of change in the value obtained by D/W at a position 20 mm away from the starting point toward the rear end from a position 10 mm away from the starting point toward the rear end is greater than 1.0,
A rate of change in the value obtained by D/W from a position 20 mm away from the starting point toward the rear end to a position 30 mm away toward the rear end from the starting point exceeds 1.0,
A deflection coefficient M (mm ⁴ )=W×D ³ at a position 10 mm away from the starting point to the rear end side is 165 mm ⁴ or more and 310 mm ⁴ or less,
A toothbrush, wherein a bending coefficient M (mm ⁴ )=W×D ³ at a position 30 mm away from the starting point toward the rear end is 600 mm ⁴ or more and 1500 mm ⁴ or less. The value obtained by D/W at a position 30 mm away from the position of the starting point toward the rear end is more than 1.0 and 1.3 or less.
The toothbrush according to claim 1. A rate of change of the deflection coefficient M (mm ⁴ ) obtained by W×D ³ from a position 20 mm away from the starting point toward the rear end to a position 30 mm away toward the rear end from the starting point. is 1.8 or more and 3.0 or less,
The toothbrush according to claim 1 or 2. The rate of change of the deflection coefficient M (mm ⁴ ) obtained by W×D ³ at a position 10 mm away from the starting point to the rear end side with respect to the position of the starting point is 1.0 or more and 1.3. is the following
A toothbrush according to any one of claims 1 to 3. The length of the head portion in the longitudinal direction is 10 mm or more and 33 mm or less.
A toothbrush according to any one of claims 1 to 4. The length of the neck portion in the longitudinal direction is 25 mm or more and 70 mm or less.
A toothbrush according to any one of claims 1 to 5. The material of the handle body including the head portion, the neck portion, and the handle portion is polypropylene resin, polyacetal resin, polystyrene resin, polyethylene terephthalate resin, polybutylene terephthalate resin, acrylonitrile-butadiene-styrene resin, polyarylate resin, polycarbonate resin, and acrylonitrile. is either a styrene resin,
A toothbrush according to any one of claims 1 to 6. The hair bundle is implanted in the head portion using a flat wire,
A toothbrush according to any one of claims 1 to 7.

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