JP7086002B2 - toothbrush - Google Patents

Description

The present invention relates to a toothbrush.
This application claims priority based on Japanese Patent Application No. 2016-21230 filed in Japan on October 28, 2016, the contents of which are incorporated herein by reference.

Patent Documents 1 to 3 propose toothbrushes having a thin head from the viewpoint of operability in the oral cavity. If the thickness of the head is reduced, a problem such as a decrease in strength becomes a problem. Therefore, a high-strength resin such as polyacetal resin (POM) is used. In particular, in the case of a flat wire type flocking in which a metal flat wire is driven into a resin head to hold the brush, the flocking strength and the folding resistance of the head portion may be insufficient.

Japanese Unexamined Patent Publication No. 7-143914 Japanese Unexamined Patent Publication No. 2011-4852 Japanese Unexamined Patent Publication No. 2011-200296

According to the studies by the present inventors, in the above-mentioned toothbrush, 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 thinning of the head portion may be impaired. Found. In particular, if the neck is widened, the operability is further impaired, and the thinness of the head is not noticeable in appearance, and the impression of the product is also impaired. However, if the neck portion is made thin, it may bend too much and conversely cause a problem in operability. In addition, further improvement in strength is required. In particular, when a general-purpose resin generally used for toothbrushes such as polypropylene (PP) is used, the problem becomes more remarkable.

One aspect of the present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a toothbrush having a thin head capable of obtaining good operability.

In order to achieve the above object, the toothbrush of one aspect of the present invention is extended to a flocked portion composed of a plurality of hair bundles, a head portion in which the flocked portion is provided on the flocked surface, and the head portion. A toothbrush provided with a neck portion and a handle portion extended to the neck portion, wherein the thickness of the head portion is 2.0 mm or more and 4.0 mm or less, and the neck portion is the most thick. The narrow width and the minimum thickness are 3.0 mm or more and 4.5 mm or less, and the center position is arranged on the flocked surface side on the rear end side of the neck portion, and the flocked surface side view. A curved surface of an arc contour having a concave surface side is formed, and a straight line connecting the center point in the thickness direction of the handle portion at the gripping center position of the toothbrush and the center point in the thickness direction of the head portion at the center position of the flocked portion. The tooth brush is characterized in that the angle formed by the plane constituting the flocked surface is 5.0 degrees or more and 10.0 degrees or less.

In the toothbrush of one aspect of the present invention, the flexural modulus of the constituent material of the neck portion may be 1000 MPa or more and 2200 MPa or less.

In the toothbrush of one aspect of the present invention, the constituent material of the neck portion may be polypropylene resin.

According to one aspect of the present invention, it is possible to realize a toothbrush having a thin head portion that can obtain good operability.

It is a top view of the toothbrush of one Embodiment of this invention. It is a side view of a toothbrush.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.
It should be noted that the following embodiments show one aspect of the present invention, do not limit the present invention, and can be arbitrarily modified within the scope of the technical idea of the present invention. Further, in the following drawings, in order to make each component easy to see, the scale and number of dimensions may be different depending on the component.

FIG. 1 is a plan view of the toothbrush of the present embodiment.
FIG. 2 is a side view of the toothbrush.
As shown in FIGS. 1 and 2, the toothbrush 1 of the present embodiment has a flocked portion 11, a head portion 12 provided with the flocked portion 11, and a neck portion 13 extending from the base end side of the head portion 12. And a handle portion 14 extending from the base end side of the neck portion 13. That is, the head portion 12, the neck portion 13, and the handle portion 14 are integrally formed. Hereinafter, a member in which the head portion 12, the neck portion 13, and the handle portion 14 are integrated is referred to as a handle body 15. In FIG. 1, the flocked portion 11 is not shown.

Here, the upper surface of the head portion 12 provided with the flocked portion 11 is referred to as a flocked surface 12a. As shown in FIGS. 1 and 2, the plane P (virtual plane) constituting the flocked surface 12a is defined as the XY plane, the direction in which the handle body 15 extends as a whole is defined as the X-axis direction, and the direction orthogonal to the X-axis is defined as the X-axis direction. It is in the Y-axis direction. The normal direction of the plane P is the Z-axis direction. In the following description, the dimension in the Y-axis direction of each member is referred to as the width of the member, the dimension in the Z-axis direction of each member is referred to as the thickness of the member, and the dimension in the X-axis direction of each member is the length of the member. Called.

The handle body 15 is integrally molded into a long shape as a whole, and can be manufactured, for example, by injection molding using a resin as a material. Polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexylene methylene terephthalate (PCT), polyacetal (POM), polyethylene naphthalate (PEN), polystyrene ( PS), acrylonitrile-butadiene-styrene resin (ABS), cellulose propionate (CP), polyarylate, polypropylene, acrylonitrile-styrene copolymer resin (AS) and the like. Among these resin materials, it is preferable to use materials such as POM, PBT, and PEN in terms of high strength and easy thinning of the head portion.

In particular, polypropylene is generally more versatile than resins such as polyacetal, is easy to process and has a low cost, but has a low flexural modulus. For example, the flexural modulus of polyacetal is about 2500 MPa, while the flexural modulus of polypropylene is about 1500 to 2000 MPa. Therefore, conventionally, polypropylene has been a difficult material to use as a material for a toothbrush having a thin head and a thin neck. However, by adopting the shape of the toothbrush of the present embodiment described later, a resin having a relatively low flexural modulus such as polypropylene can also be used.

In the present embodiment, the flexural modulus of the constituent material of the handle body 15, particularly the neck portion 13, is preferably 1000 MPa or more and 2200 MPa or less. If the flexural modulus is less than 1000 MPa, sufficient strength may not be obtained when the neck portion 13 is thinned. Further, if the flexural modulus exceeds 2200 MPa, the hardness increases, but the bending elasticity may become brittle.

As the above resin, one kind of resin may be used alone, or two or more kinds of resins may be used in combination. Further, the handle body 15 may be partially or wholly covered with a soft resin. Since a part or all of the handle portion 14 is coated with the soft resin, the fit of the hand when the user grips the handle portion 14 is improved, and the gripped fingers can be prevented from slipping. Examples of the soft resin include a resin having a shore A of 90 or less, and more preferably a resin having a shore A of 10 to 40. Examples of such soft resins include elastomer resins such as polyolefin-based elastomers, styrene-based elastomers, polyester-based elastomers, and polyurethane-based thermoplastic elastomers, and silicon and the like.

The overall length of the handle body 15 can be determined in relation to operability and the like. The total length of the handle body 15 is, for example, about 100 to 200 mm.

The head portion 12 has a substantially quadrangular flat plate shape in which four tops are cut into curved corners in a plan view. A plurality of flocked holes 12h are provided on the flocked surface 12a, which is the upper surface of the head portion 12. The hair follicles 17 in which the hair follicles are bundled are planted in each of the hair transplant holes 12h to form a hair transplant portion 11 composed of a plurality of hair follicles 17. Of the plurality of hair follicle holes 12h, the distance d1 between the hair follicle hole 12h located on the most tip side of the head portion 12 and the tip of the head portion 12, and the hair follicle hole 12h and the head portion 12 located on the most proximal side of the head portion 12. The distance d2 to the base end is set to be equal. In other words, the boundary position K1 between the neck portion 13 and the head portion 12, which will be described later, is a position separated from the hair follicle hole 12h located on the most proximal side of the head portion 12 to the neck portion 13 side by a distance equal to the distance d1. ..

The dimensions of the head portion 12 are determined in consideration of characteristics such as intraoral operability. If the width of the head portion 12 is too large, the operability in the oral cavity is deteriorated, and if it is too small, the number of hair bundles 17 to be transplanted is too small, and the cleaning effect is likely to be impaired. Therefore, the width of the head portion 12 is set to, for example, about 5 mm to 16 mm.

If the length of the head portion 12 is too long, the operability in the oral cavity is likely to be impaired, and if it is too short, the number of hair bundles 17 to be transplanted is too small, and the cleaning effect is likely to be impaired. Therefore, the length of the head portion 12 is set in the range of, for example, 10 mm to 33 mm.

The shape of the hair follicle hole 12h is not particularly limited, and may be a circle such as a perfect circle or an ellipse, or a polygon such as a triangle or a quadrangle. The number of hair follicles 12h is not particularly limited, and is set in the range of, for example, 10 to 60. The diameter of the hair follicle hole 12h is determined according to the thickness of the hair follicle 17, and is set in the range of, for example, 1 mm to 3 mm. The arrangement pattern of the hair follicle holes 12h is not particularly limited, and may be any arrangement pattern such as a so-called lattice pattern or a staggered pattern.

The hairs constituting the hair bundle 17 include hairs whose diameter gradually decreases toward the tip (tapered hair) and hairs having substantially the same outer diameter except for the rounded portion of the tip (straight hair). Can be mentioned. The material of the hair is, for example, polyamide such as 6-12 nylon and 6-10 nylon, polyester such as PET, PBT, polytrimethylene terephthalate (PTT), PEN, polybutylene naphthalate (PBN), and polyolefin such as PP. , Olefin-based elastomer, synthetic resin material such as styrene-based elastomer can be used. These resin materials may be used alone or in combination of two or more. Further, the hair may have a multi-core structure having a core portion and at least one or more layers of sheath portions provided on the outside of the core portion.

The cross-sectional contour of the hair is not particularly limited, and is, for example, a circle such as a perfect circle or an ellipse, a polygon such as a triangle, a quadrangle, a pentagon or a hexagon, a star shape, a three-leaf clover shape, or a four-leaf clover shape. And so on.

The thickness of the hair is not particularly limited, and when the cross-sectional contour is circular, it is, for example, 3 mil to 11 mil (1 mil = 1/1000 inch = 0.025 mm). The hair bundle may be composed of hairs of the same thickness, or may be a combination of two or more kinds of hairs of different thicknesses. The hair length is not particularly limited and is set to, for example, 6 mm to 12 mm.

As shown in FIG. 2, on the flocked surface 12a side on the tip side of the handle portion 14, the center position (center of curvature) is arranged on the opposite side of the flocked surface 12a (lower side than the flocked surface 14 in FIG. 2). A curved surface 14a having an arc contour is formed in which the flocked surface 12a side is convex when viewed from the side. Similarly, on the opposite side of the flocked surface 12a on the tip side of the handle portion 14, the center position is arranged on the opposite side of the flocked surface 12a, and a curved surface 14b having an arc contour is formed in which the flocked surface 12a side is convex in side view. Has been done.

Further, on the flocked surface 12a side on the rear end side of the neck portion 13, the center position (center of curvature) is arranged on the flocked surface 12a side (above the handle portion 14 in FIG. 2), and the flocked surface 12a side is viewed from the side. A curved surface 13a having a concave arc contour is formed. More specifically, the neck portion 13 is a surface (curved surface or flat surface) on the flocked surface 12a side in the thickness direction of the handle portion 14 from the front end side region in the long axis direction to the rear end side region intersecting with the head portion 12. However, a curved surface 13a having an arc contour in which the flocked surface 12a side is concave when viewed from the side view from the width direction orthogonal to the major axis direction and the thickness direction is formed and curved. The center of curvature of the curved surface 13a is arranged above the curved surface 13a in the thickness direction. Similarly, on the side opposite to the flocked surface 12a on the rear end side of the neck portion 13, the center position (center of curvature) is arranged on the flocked surface 12a side (upper side), and the arc contour where the flocked surface 12a side is concave in side view. Curved surface 13b is formed.

The curved surface 13a and the curved surface 14a continuously change the angle of intersection between the tangent line and the flocked surface 12a in the side view as they advance in the length direction of the handle portion 14, but at the intersection of the curved surface 13a and the curved surface 14a. Crosses at an angle α1 where the crossing angles of the tangents are not 0 degrees or 180 degrees. Therefore, the ridge line K2 is formed at the intersection of the curved surface 13a and the curved surface 14a.

For the curved surface 13b and the curved surface 14b, the intersection angle between the tangent line and the flocked surface 12a in the side view continuously changes as the handle portion 14 advances in the length direction, but the intersection between the curved surface 13b and the curved surface 14b At an angle α2 where the crossing angles of the tangents are not 0 degrees or 180 degrees. Therefore, the ridge line K3 is formed at the intersection of the curved surface 13b and the curved surface 14b. Therefore, the neck portion 13 and the handle portion 14 sandwich the curved surfaces 14a and 14b of the arc contour in which one side in the length direction sandwiching the ridge lines K2 and K3 is convex on the flocked surface 12a side and the ridge lines K2 and K3. The other side in the length direction is connected to the curved surfaces 13a and 13b having an arc contour in which the flocked surface 12a side is concave in the side view, so that the flocked surface 12a is formed in a substantially S shape in the side view.

The boundary on the rear end side of the neck portion 13 is defined by the ridge lines K2 and K3. Therefore, the rear end side of the ridge lines K2 and K3 is the range in which the handle portion 14 is arranged, and the range between the range in which the head portion 12 is arranged and the range in which the handle portion 14 is arranged. The neck portion 13 is arranged in the.

The end portion on the flocked surface 12a side (rear end side from the ridge line K2 in the side view) on the tip end side of the handle portion 14 is the finger contact portion 19. The apex on the tip end side of the finger rest portion 19 is defined by the ridge line K2. As shown in FIG. 1, this apex position (ridge line K2) is the position of the apex that is the shortest distance to the head portion 12 in front view. The user can stably operate the toothbrush 1 by holding the handle portion 14 so as to put his thumb on the finger rest portion 19.

The neck portion 13 integrally connects the head portion 12 and the handle portion 14. As an example, the neck portion 13 has the thinnest and small cross-sectional area at a position slightly away from the boundary position K1 (tip of the neck portion 13) between the head portion 12 and the neck portion 13 toward the handle portion 14. It extends to the rear end side with the same area, and is formed in a shape that gradually expands to the boundary K2 with the handle portion 14 on the rear end side. As described above, the neck portion 13 gradually becomes thicker from the head portion 12 side toward the handle portion 14, so that the neck portion 13 bends even when the toothbrush 1 is used in various gripping and polishing methods. It is absorbed and has excellent usability. However, from the viewpoint of usability, the neck portion 13 has elasticity and needs to be appropriately bent.

The length of the neck portion 13 is preferably 25 mm to 70 mm because the neck portion 13 touches the lips when the head portion 12 is inserted into the oral cavity.

As shown in FIG. 1, the gripping center position G1 of the toothbrush 1 is located on the handle portion 14. The gripping center position G1 is defined as a position 37 mm away from the ridge line K2 on the rear end side of the handle portion 14.

There are two ways to hold a toothbrush: the "palm grip" where you put your thumb near the finger pad and hold the handle with your entire palm, and the "pen grip" where you put your thumb near the finger pad and hold the pen. It has been known. The present inventors have diligently studied the position where a force is applied when operating the toothbrush when the various toothbrushes are gripped in each way of holding. As a result, it was clarified that a part of the finger hits a position 37 mm on average from the apex of the finger rest (the position of the ridge line K2), and this point becomes one of the centers of the operation points. Therefore, this position is defined as the gripping center. At the same time, it was also clarified that this position almost coincides with the position of the center of gravity of many general toothbrushes.

As shown in FIG. 2, the center point G2 in the thickness direction of the handle portion 14 at the gripping center position G1 of the toothbrush 1 and the center point S2 in the thickness direction of the head portion 12 at the center position S1 (see FIG. 1) of the flocked portion 11. If the virtual straight line connecting the above is a straight line N, the straight line N is located above the plane P (in the + Z direction). In other words, the handle body 15 has a curved shape so that the handle portion 14 having the gripping center position G1 is located closer to the flocked portion 11 than the flocked surface 12a of the head portion 12.

In a conventional toothbrush in which the handle body extends substantially linearly, the present inventors have thinned the head portion and thinned the neck portion, the head portion and the neck portion are bent, and the flocked portion is on the back side of the head portion (FIG. In terms of 2, it was found that the displacement is likely to occur in the -Z axis direction). Especially when the neck part bends when brushing, the flocked part is displaced to the back side of the head part (that is, the direction away from the teeth and gums) from the normal position, and the force applied to the handle part is applied to the flocked part. It becomes difficult to be sufficiently transmitted to. As a result, it was found that the operability of the handle portion was significantly reduced.

Therefore, as a result of diligent studies by the present inventors, the handle portion 14 side of the handle body 15 is bent toward the flocked portion 11 side with respect to the plane P constituting the flocked surface 12a as in the toothbrush 1 of the present embodiment described above. Further, by optimizing the parameters such as the angle θ formed by the straight line N and the plane P, it was conceived that the bending of the handle body 15 can offset the bending of the head portion 12 and the neck portion 13. As described above, according to the toothbrush 1 of the present embodiment, even if the head portion 12 and the neck portion 13 are bent when the head portion 12 is thin and the neck portion 13 is thinned, the handle operability is maintained well. It is possible to realize a possible toothbrush 1 that is excellent in both intraoral operability and handle portion operability.

Hereinafter, characteristic design parameters of the toothbrush 1 of the present embodiment will be described.
[Head thickness t]
The thinner the thickness t of the head portion 12, the higher the operability in the oral cavity, but if it is too thin, the strength of the head portion 12 tends to be insufficient. Therefore, the thickness t of the head portion 12 can be determined in consideration of the constituent materials of the handle body 15, the flexural modulus, and the like. The thickness t of the head portion 12 is set in the range of 2.0 mm to 4.0 mm. The thickness t of the head portion 12 is more preferably about 2.5 mm to 3.5 mm.

[Minimum width W1 of neck part]
The smaller the minimum width W1 of the neck portion 13, the better the operability in the oral cavity, but if it is too small, the strength of the neck portion 13 tends to be insufficient. Therefore, the minimum width W1 of the neck portion 13 can be determined in consideration of the constituent materials of the handle body 15, the flexural modulus, and the like. The minimum width W1 of the neck portion 13 is set to 3.0 mm to 4.5 mm. The minimum width W1 of the neck portion 13 is more preferably about 3.5 mm to 4.3 mm.

[Minimum thickness of neck D1]
The minimum thickness D1 of the neck portion 13 can be defined as the thickness of the neck portion 13 at a position where the width of the neck portion 13 is minimized in the X-axis direction. That is, in the toothbrush 1 of the present embodiment, the shape of the cross section orthogonal to the extending direction of the neck portion 13 is substantially circular, and the position and thickness at which the width of the neck portion 13 is minimized in the X-axis direction are the minimum. It matches the position of. However, the shape of the cross section orthogonal to the extending direction of the neck portion 13 does not necessarily have to be circular, and may be, for example, a polygonal shape. Further, the shape of the cross section orthogonal to the extending direction of the neck portion 13 may differ depending on the position in the X-axis direction, and the position where the width of the neck portion 13 is minimized and the position where the thickness is minimized are not necessarily the minimum. It does not have to match.

Similar to the minimum width W1 of the neck portion 13, the smaller the minimum thickness D1 of the neck portion 13 is, the more the oral operability can be improved, but if it is too small, the strength of the neck portion 13 tends to be insufficient. Therefore, the minimum thickness D1 of the neck portion 13 can be determined in consideration of conditions such as the constituent material of the handle body 15 and the flexural modulus. The minimum thickness D1 of the neck portion 13 is set to 3.0 mm to 4.5 mm. The minimum thickness D1 of the neck portion 13 is more preferably about 3.5 mm to 4.3 mm. In the case of the present embodiment, the width and the thickness are the same because the shape of the cross section orthogonal to the extending direction of the neck portion 13 is substantially circular. That is, the minimum diameter of the neck portion 13 is preferably 3.0 mm to 4.5 mm, more preferably 3.5 mm to 4.3 mm.

Here, the shape factors of the front end region and the rear end region in the neck portion 13 will be described.
The tip region (the region between the boundary position K1 with the head portion 12 and the position 10 mm away from the boundary position K1 on the rear end side) in the neck portion 13 enters the oral cavity and is physically connected to the vicinity of the cleaning site. This is an area with a lot of interference. Therefore, from the viewpoint of intraoral operability, it is preferable that the shape of the head portion 12 on the side of the flocked surface 12a in the region is on the same plane as the flocked surface 12a (plane) or in a parallel relationship. .. Therefore, the thickness of the neck portion 12 is D, the thickness of the neck portion 12 above the plane of the neck portion 12 is D11, and the thickness of the lower side of the neck portion 12 is D12 (D = D11 + D12) with the plane including the flocked surface 12a as a boundary in the side view. ), It is desirable that D12> D11 always in the neck tip region, and the ratio of D12 to D11 remains constant (the change in D11 / D12 in the tip region is in the range of 1.0 ± 0.15).

The rear end region (the region between the ridge line K2 and the position 20 mm away from the ridge line K2 on the tip side) in the neck portion 13 is different from the above-mentioned tip region, and there are few cases where it enters the oral cavity. The rear end region has an appropriate gripping center point angle θ and gripping center point height h in order to suppress excessive bending due to the thin head and thin neck (that is, to improve intraoral operability and handle operability). It plays the role of making a shape change to establish. In particular, since the shape (upper side) on the flocked surface 12a side in the rear end region independently contributes to the setting of the gripping center point angle θ, the shape in the side view is steeper (larger curvature) than the tip region. ) Set in arc shape. Further, since the thickness increases due to this shape change, it becomes possible to control the bending at the base of the neck portion 12 where the load due to brushing tends to concentrate.
On the other hand, the back side (lower side) in the rear end region forms a similar arc shape in accordance with the shape change in the upper side view, but it is necessary to increase the thickness in order to suppress the bending. Compared to the upper side, it is formed in a gentle arc shape (small curvature). At this time, the thickness D11 at the position moved 20 mm from the ridge line K2 to the head portion 12 side (tip side) is the thickness D11 (20), and the case where the thickness D11 is moved 10 mm from the ridge line K2 to the tip side is the thickness D11 (10). Assuming that the case of the ridgeline is the thickness D11 (0) and the thickness D12 is also expressed in the same manner, the following relationship holds.

(1) At a position 20 mm away from the ridge line K2 on the tip side:
The ratio of the upper thickness D11 to the thickness D at the position is 40 ± 10%.
At a position 10 mm away from the ridgeline K2 on the tip side:
The ratio of the upper thickness D11 to the thickness D at the position is 40% or more and 90% or less, preferably 60% or more and 80% or less.
At the position of 0 mm (ridge line K2):
The ratio of the upper thickness D11 to the thickness D at the position is 45 or more, preferably 75% or more, more preferably 80%, and 85% or more. The upper limit is preferably 95% or less, more preferably 90% or less.

The ratio of the thickness D11 increases as the angle θ increases. Further, when the head portion 12 is made thin, the thickness itself is small, so that the ratio of the upper thickness D11 becomes larger in order to obtain a predetermined angle θ.
When the ratio of the thickness D11 is not more than the lower limit value, the shape becomes close to a straight shape and a predetermined gripping center point angle cannot be obtained. Further, even if the angle is set, the thickness D12 becomes larger than necessary at the base of the neck portion 13, and the effect as a thin neck is reduced. When the thickness D12 exceeds the upper limit value, the bending of the neck portion 13 starts at an early stage, so that it is difficult to obtain an appropriate gripping center point angle and the operability in the oral cavity is lowered.

(2) The change in thickness D11 (D11 (10) / D11 (20)) at a position 20 mm away from the ridge line K2 on the tip side and a position 10 mm away from the ridge line K2 on the tip side is 1.2 or more. It is preferably 1.4 or more, more preferably 1.7 or more. Further, the upper limit of the change in the thickness D11 (D11 (10) / D11 (20)) is 2.5.
When the change in thickness D11 (D11 (10) / D11 (20)) at a position 20 mm away from the ridge line K2 on the tip side and a position 10 mm away from the ridge line K2 on the tip side is less than the above lower limit value, Since the straight shape continues to the base of the neck portion 13, a predetermined gripping center point angle cannot be obtained. If the change in thickness D11 (D11 (10) / D11 (20)) at a position 20 mm away from the ridge line K2 on the tip side and a position 10 mm away from the ridge line K2 on the tip side exceeds the above upper limit value, Since the bending of the neck portion 13 starts at an early stage, it is difficult to obtain an appropriate gripping center point angle, and the operability in the oral cavity is also reduced.
The change in D11 between the position 10 mm and the position 0 mm from the ridge line K2 to the tip side is 1.4 or more, preferably 1.8 or more, and more preferably 1.9 or more. The upper limit of the change of D11 at the position of 10 mm and the position of 0 mm on the tip side is 3.0.
When the change of D11 at the position of 10 mm and the position of 0 mm from the ridge line K2 to the tip side is less than the above lower limit value, the straight shape continues to the root of the neck portion 13, so that a predetermined gripping center point angle cannot be obtained. When the change of D11 at the position of 10 mm and the position of 0 mm from the ridge line K2 to the tip side exceeds the above upper limit value, the bending of the neck portion 13 starts at an early stage, so that it is difficult to obtain an appropriate gripping center point angle, and Oral operability is also reduced.

The rate of change of the thickness D12 (D12 (20) / D12 (10) is 1.3 or more, preferably 1) at a position 20 mm away from the ridge line K2 on the tip side and a position 10 mm away from the ridge line K2 on the tip side. It is 0.4 or more.
The change in the thickness D12 between the position 10 mm and the position 0 mm from the ridge line K2 to the tip side is 1.3 or more, preferably 1.4 or more.
When it is not more than the above lower limit value, the lower side is not curved according to the change in the shape of the upper side, and the finger rest portion is unnecessarily thick and difficult to hold. There is no particular upper limit, but it is preferable that it does not exceed the change on the upper side in the same section.
The range of the thickness of the position of the ridge line K2 (D11 (0) + D12 (0)) is preferably 7 mm or more and 15 mm or less, more preferably 8.4 mm or more and 13.5 mm or less, and 8.8 or more and 10 mm or less. More preferred.

[Distance a between the base end of the head and the tip of the finger pad]
The larger the distance a between the base end of the head portion 12 (boundary position K1 between the neck portion 13 and the head portion 12) and the tip of the finger rest portion 19 (boundary K2 between the neck portion 13 and the handle portion 14), the more flocked hair is formed. The portion 11 reaches the depths of the oral cavity, and while the cleaning effect can be enhanced to every corner of the oral cavity, the bending of the neck portion 13 becomes large. On the other hand, the smaller the distance a, the smaller the deflection of the neck portion 13, but the more difficult it is for the flocked portion 11 to reach the depth of the oral cavity. Therefore, the distance a is set to, for example, about 25 mm to 70 mm, although it depends on conditions such as the constituent material of the handle body 15 and the flexural modulus.

[Gripping center point angle θ]
A straight line N connecting the center point G2 in the thickness direction of the handle portion 14 at the gripping center position G1 of the toothbrush 1 and the center point S2 in the thickness direction of the head portion 12 at the center position S1 of the hair-planting portion 11 constitutes the hair-planting surface 12a. The angle θ formed by the plane P is hereinafter referred to as a gripping center point angle θ.

If the gripping center point angle θ is too large, the difference between the extending direction of the handle portion 14 and the extending direction of the head portion 12 becomes large, and the operability of the handle portion 14 deteriorates. Further, if the gripping center point angle θ is too small, the shape of the handle body 15 becomes linear, and the original effect of the present embodiment cannot be obtained. In consideration of these, the gripping center point angle θ is set to 5.0 degrees or more and 10.0 degrees or less. The gripping center point angle θ is more preferably 6.0 degrees or more and 8.0 degrees or less.

[Gripping center point height h]
The distance between the center point G2 in the thickness direction of the handle portion 14 at the gripping center position G1 of the toothbrush 1 and the plane P constituting the flocked surface 12a is defined as the gripping center point height h.

The height h of the gripping center point is set to 6.0 mm or more and 15.5 mm or less. The grip center point height h is preferably 7.0 mm or more at the lower limit, preferably 15.0 mm or less at the upper limit, more preferably 14.5 mm or less, further preferably 13.5 mm or less, and further preferably 12.0 mm or less. It is preferable, and 11.0 mm or less is particularly preferable. The upper and lower ranges are preferably 7.0 mm or more and 15.0 mm or less, more preferably 7.0 mm or more and 14.5 mm or less, further preferably 7.0 mm or more and 13.5 mm or less, and 7.0 mm or more and 12 It is more preferably 9.0 mm or less, and particularly preferably 7.0 mm or more and 11.0 mm or less.

[Example]
Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples, and can be appropriately modified and carried out without departing from the gist thereof.

Toothbrushes of Examples 1 to 10 and Comparative Examples 1 to 4 were produced by an injection molding method according to the specifications shown in Table 1. In the above toothbrush, the width, length, thickness and shape of the handle portion are all the same. Various resins shown in Table 1 were injection-molded to obtain integrally molded parts of the head portion, the neck portion and the handle portion shown in FIGS. 1 and 2. The arrangement of the hair follicles was 3 holes × 1 row, 4 holes × 6 rows, 3 holes × 1 row from the tip of the head portion toward the neck portion. The width and length of the head portion are shown in Table 1. A toothbrush was prepared by implanting a bundle of tapered bristles (7.5 mil) made of PBT filament in the head portion by flat wire flocking.

Two items, intraoral operability and handle operability, were listed as evaluation items for each sample. Regarding the operability in the oral cavity, "very excellent" is "◎", "excellent" is "○", "slightly inferior" is "△", and "very inferior". Was set to "x". Similarly, regarding the handle operability, "very excellent" is "◎", "excellent" is "○", "slightly inferior" is "△", and "very inferior". "Is" was changed to "x".

As shown in Table 1, in the toothbrush of Comparative Example 1, both the gripping center point angle θ and the gripping center point height h are out of the numerical range of the present invention. That is, in the toothbrush of Comparative Example 1, the handle body has a shape that is relatively close to a straight line. Therefore, it was confirmed that the toothbrush of Comparative Example 1 was inferior in oral operability and handle operability. Further, in the toothbrush of Comparative Example 2, the head portion thickness t, the minimum width W1 of the neck portion, and the minimum thickness D1 of the neck portion are out of the numerical range of the present invention. Therefore, it was confirmed that the toothbrush of Comparative Example 2 was inferior in oral operability. Further, it was confirmed that the toothbrush of Comparative Example 3 was inferior in intraoral operability and handle operability because the height h of the gripping center point was out of the numerical range of the present invention. It was confirmed that the toothbrush of Comparative Example 4 was inferior in oral operability and handle operability because both the gripping center point angle θ and the gripping center point height h were out of the numerical range of the present invention.

On the other hand, in the toothbrushes of Examples 1 to 10, the head portion thickness t, the minimum width W1 of the neck portion, the minimum thickness D1 of the neck portion, the gripping center point angle θ, and the gripping center point height h are all included. Parameters are within the numerical range of the present invention. As a result, it was confirmed that the toothbrush is excellent in both intraoral operability and handle operability even if the neck portion is bent.

Generally, when flat wire flocking is adopted, stress is applied to the head portion due to flat wire driving. When the head part is thin, the strength against deformation when a force is applied is low, while when the neck part is thick and the strength is high, the stress when brushing the teeth is concentrated on the head part, and the bending of the head part becomes large. Usability may decrease. In this case, as in the toothbrush 1 of the present embodiment, by making the neck portion thinner and giving it a certain degree of flexibility, the stress when brushing the teeth can be dispersed from the head portion to the entire neck portion, and the usability is improved. do. Therefore, in the case of flat line flocking, the effect of the present invention can be obtained particularly remarkably.

1 ... toothbrush, 11 ... flocked part, 12 ... head part, 12a ... flocked surface, 13 ... neck part, 14 ... handle part, 17 ... hair bundle.

Claims (5)

A flocked part consisting of multiple hair bundles and
A head portion in which the flocked portion is provided on the flocked surface and a head portion.
The neck part extended to the head part and
A toothbrush provided with a handle portion extended to the neck portion.
The thickness of the head portion is 2.0 mm or more and 4.0 mm or less.
The minimum width and minimum thickness of the neck portion are 3.0 mm or more and 4.5 mm or less.
On the flocked surface side on the rear end side of the neck portion, a curved surface having an arc contour is formed in which the center position is arranged on the flocked surface side and the flocked surface side is concave in the side view.
On the side opposite to the flocked surface on the tip end side of the handle portion, the center position is arranged on the opposite side to the flocked surface, and a second curved surface of an arc contour having the flocked surface side convex in the side view is formed.
A straight line connecting the center point in the thickness direction of the handle portion at the gripping center position of the toothbrush and the center point in the thickness direction of the head portion at the center position of the hair-planted portion and a plane constituting the hair-planted surface are formed. The angle is 5.0 degrees or more and 10.0 degrees or less,
The head portion, the neck portion, and the handle portion each have a hard portion made of a hard resin material.
The hard resin materials include polypropylene, polyethylene terephthalate, polybutylene terephthalate, polycyclohexylene methylene terephthalate, polyacetal, polyethylene naphthalate, polystyrene, acrylonitrile / butadiene / styrene resin, cellulose propionate, polyallylate, polycarbonate, and acrylonitrile / styrene. Selected from copolymer resins,
The hard portion of the head portion, the hard portion of the neck portion, and the hard portion of the handle portion are integrally molded by using one kind of the hard resin material alone. Characterized toothbrush. The toothbrush according to claim 1, wherein the flexural modulus of the constituent material of the neck portion is 1000 MPa or more and 2200 MPa or less. The toothbrush according to claim 1 or 2, wherein the constituent material of the neck portion is polypropylene resin. When viewed from the side with the plane including the flocked surface as the boundary,
At the boundary position between the neck portion and the handle portion on the flocked surface side, the thickness of the neck portion at the boundary position on the flocked surface side with respect to the plane of the neck portion. Is 45% or more and 95% or less.
The toothbrush according to any one of claims 1 to 3. Both the width and the thickness of the neck portion gradually increase toward the handle portion in the region where the curved surface of the concave arc contour is formed.
The toothbrush according to any one of claims 1 to 4.

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