CN114025642A

CN114025642A - Tooth brush

Info

Publication number: CN114025642A
Application number: CN202080044637.4A
Authority: CN
Inventors: 佐竹茉以
Original assignee: Lion Corp
Current assignee: Lion Corp
Priority date: 2019-06-28
Filing date: 2020-06-23
Publication date: 2022-02-08
Anticipated expiration: 2040-06-23
Also published as: JP7378472B2; KR20220029540A; CN114025642B; TW202128056A; JPWO2020262352A1; WO2020262352A1

Abstract

The invention aims to provide a toothbrush which has good operability and can brush at a proper brushing pressure even if an excessive brushing pressure is applied. The toothbrush has: a deformation part (70) which is arranged on the holding part (30) and deforms due to an external force in a first direction orthogonal to the hair planting surface; a first region (A1) that is not deformed by an external force in a first direction; and a second region (A2) that is not deformed by the external force in the first direction. The deformation portion has a hard portion (70H) formed of a hard resin and connecting the first region and the second region, and a soft portion formed of a soft resin and covering at least a part of the hard portion. When the length of the hard portion in the first direction is d and the length of the hard portion in the second direction perpendicular to the longitudinal direction and the first direction is W, the relationship of W > d is satisfied over the entire longitudinal direction, and at least one of the length d of the hard portion in the first direction and the length W of the hard portion in the second direction is gradually increased from the front end to the rear end in the longitudinal direction and gradually decreased through a maximum value.

Description

Tooth brush

Technical Field

The present invention relates to toothbrushes.

The present application claims priority based on japanese patent application No. 2019-121550, filed in japan on 28/6/2019, and the contents of which are incorporated herein by reference.

Background

The proportion of people with 20 teeth at age 80 is about 5, while the proportion of caries (root caries) in older people is increasing. Root caries is a tooth decay of dentin exposed by gingival atrophy, and the tooth decay progresses rapidly because the constitutional ratio of organic components is higher in dentin than in enamel. One of the causes of the gingival atrophy is excessive brushing in which brushing is performed at a brushing pressure higher than an appropriate value.

Conventionally, as a toothbrush for reducing an excessive brushing pressure, for example, a toothbrush described in patent document 1 is disclosed. In the toothbrush described in patent document 1, when the toothbrush is gripped by a palm grip method for brushing, a part made of a thermoplastic resin among parts gripped by a thumb and an index finger of the handle portion is formed in a U shape that is open to the hair-implanted surface side, and the periphery of the part made of the thermoplastic resin is covered with a soft resin such as an elastomer material.

The toothbrush having the above structure disclosed in patent document 1 includes the following: by applying the elastic force to the above-mentioned part of the handle in addition to the elastic force applied to the neck by the load of the head, the excessive brushing pressure is reduced while the teeth and the gums are given a soft and comfortable operability without damaging the gums.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2000-004944

Disclosure of Invention

Problems to be solved by the invention

However, when the above-described conventional toothbrush is loaded with an excessive brushing pressure, the excessive brushing pressure cannot be reduced because the amount of deflection is small, and thus brushing cannot be performed within a range of an appropriate brushing pressure. Therefore, a method of increasing the amount of the soft resin used to increase the amount of deflection and reduce the excessive brushing pressure has been considered, but the amount of deflection before reaching the appropriate brushing pressure is excessively large, and therefore, there is a problem of poor operability.

The present invention has been made in view of the above-described problems, and an object thereof is to provide a toothbrush which has good operability and can perform brushing at an appropriate brushing pressure even when an excessive brushing pressure is applied.

Means for solving the problems

According to a first aspect of the present invention, there is provided a toothbrush comprising: a head portion provided on a distal end side in a longitudinal direction and having a hair-setting surface; a grip portion disposed on a rear end side of the head portion; and a neck portion disposed between the bristle surface and the grip portion, the head portion and the neck portion being formed of a hard resin, the toothbrush including: a deformation portion disposed on the holding portion and deformed by an external force in a first direction orthogonal to the flocked surface; a first region which is disposed on the distal end side of the deformation portion and is not deformed by an external force in the first direction; and a second region that is disposed on the rear end side of the deformation portion and is not deformed by an external force in the first direction, wherein the grip portion is formed of the hard resin at least in a part of a cross section orthogonal to the long axis direction from at least a front end of the grip portion to the second region in the long axis direction, and the deformation portion includes: a hard portion formed of the hard resin and connecting the first region and the second region; and a soft portion formed of a soft resin and covering at least a part of the hard portion, wherein the hard portion satisfies a relationship of W > d over the entire long axis direction when a length in the first direction is denoted by d and a length in a second direction orthogonal to the long axis direction and the first direction is denoted by W, and at least one of the length d in the first direction of the hard portion and the length W in the second direction of the hard portion is gradually increased from a front end to a rear end in the long axis direction and gradually decreased through a maximum value.

In the toothbrush according to one aspect of the present invention, the hard portion satisfies d ≦ 3.5mm in the entire longitudinal direction.

In the toothbrush according to one aspect of the present invention, when the maximum value of the length d in the first direction is a and the minimum value of the end portion is b, the value represented by a/b is 1.1 or more and 2.0 or less.

In the toothbrush according to one aspect of the present invention, the maximum value a is 1.5mm or more and 3.5mm or less.

In the toothbrush according to one aspect of the present invention, when the maximum value of the length W in the second direction is represented by e and the minimum value of the end portion is represented by f, the value represented by e/f is 1.2 or more and 7.5 or less.

In the toothbrush according to one aspect of the present invention, the maximum value e is 5.0mm or more and 15.0mm or less, and the minimum value f is 2.0mm or more and 8.0mm or less.

In the toothbrush according to one aspect of the present invention, a length of the deformation portion in the longitudinal direction as viewed in the first direction is 10% or more and 30% or less of a length of the holding portion in the longitudinal direction.

Effects of the invention

The present invention can provide a toothbrush which has good operability and can brush with an appropriate brushing pressure even when an excessive brushing pressure is applied.

Drawings

Fig. 1 is a view showing a first embodiment of the present invention, and is a front view of a toothbrush 1.

Fig. 2 is a sectional view of the toothbrush 1 cut by a plane including the center in the width direction.

Fig. 3 is a front view of the hard portion H constituting the toothbrush 1.

Fig. 4 is a sectional view taken along line a-a of fig. 1.

Fig. 5 is a partially enlarged front view of the hard portion 70H in the hard portion H.

Fig. 6 is a side view of fig. 5.

Fig. 7 is a diagram showing a relationship between displacement and load when a load is applied to the back surface side of the head.

Detailed Description

Next, an embodiment of the toothbrush of the present invention will be described with reference to fig. 1 to 7.

The following embodiment is an embodiment of the present invention, and is not intended to limit the present invention, and may be arbitrarily modified within the scope of the technical idea of the present invention. In the drawings below, scales, numbers, and the like of the respective structures are different from those of actual structures in order to facilitate understanding of the respective structures. In the following description, the direction perpendicular to the flocked surface in a side view is referred to as the thickness direction, the flocked surface side in the thickness direction is referred to as the front surface side, and the side opposite to the flocked surface is referred to as the back surface side.

Fig. 1 is a front view of a toothbrush 1 of the present embodiment. Fig. 2 is a cross-sectional view of the toothbrush 1 cut along a plane including the center in the width direction (vertical direction in fig. 1). Fig. 3 is a front view of the hard portion H constituting the toothbrush 1.

The toothbrush 1 of the present embodiment includes: a head 10 which is arranged on a distal end side in a longitudinal direction (hereinafter simply referred to as a distal end side) and into which a bundle of bristles is implanted (not shown); a neck portion 20 extending from a rear end side in the longitudinal direction of the head portion 10 (hereinafter simply referred to as a rear end side); and a grip 30 extending from the rear end of the neck 20 and having a deformation portion 70 (hereinafter, the head 10, the neck 20, and the grip 30 are collectively referred to as a handle 2).

The toothbrush 1 of the present embodiment is a molded body in which a hard portion H made of a hard resin and a soft portion E made of a soft resin are integrally molded. The hard portion H constitutes at least a part of each of the head 10, the neck 20, the grip portion 30, and the deformable portion 70. The soft portion E constitutes a part of each of the grip portion 30 and the deforming portion 70. More specifically, the head 10 and the neck 20 of the present embodiment are each formed of a hard resin, but may be formed of a part of the soft resin, for example, a part of the surface may be covered with the soft resin. A part of the grip portion 30 including the deformable portion 70 of the present embodiment is formed of both a hard resin and a soft resin (details will be described later).

[ head part 10]

The head 10 has a flocked surface 11 on one side in the thickness direction (direction orthogonal to the paper surface in fig. 1). In the following description, the side of the flocked surface 11 in the thickness direction is referred to as the front surface side in the front direction, the side opposite to the flocked surface is referred to as the back surface side, and the direction orthogonal to the thickness direction and the longitudinal direction is referred to as the width direction (or appropriately referred to as the side surface direction). A plurality of implantation holes 12 are formed in the implantation surface 11. A tuft (not shown) having bristles is planted in the planting hole 12.

The width of the head 10, that is, the length in the width direction parallel to the hair-planted surface 11 on the front side and orthogonal to the longitudinal direction (hereinafter, simply referred to as width) is not particularly limited, and is preferably 7mm to 13mm, for example. If the above-mentioned lower limit value is not less than the above-mentioned upper limit value, the operability in the oral cavity can be further improved.

The length of the head 10 in the longitudinal direction (hereinafter simply referred to as length) is not particularly limited, and is preferably 10mm to 33mm, for example. If the length of the head 10 is equal to or greater than the lower limit, the area of the implanted hair bundle can be sufficiently secured, and if the length is equal to or less than the upper limit, the operability in the oral cavity can be further improved. In the present embodiment, the boundary between the neck portion 20 and the head portion 10 in the longitudinal direction is a position where the width of the neck portion 20 is the minimum value in the direction from the neck portion 20 toward the head portion 10. When the region where the width of the neck portion 20 is the minimum value exists at a constant length (when the position where the width of the neck portion 20 is the minimum value is not one), the boundary in the longitudinal direction between the neck portion 20 and the head portion 10 is the position closest to the head distal end side where the width of the neck portion 20 is the minimum value.

The length of the head 10 in the thickness direction (hereinafter, simply referred to as thickness) may be determined in consideration of the material and the like, and is preferably 2.0mm or more and 4.0mm or less. If the thickness of the head 10 is equal to or greater than the lower limit value, the strength of the head 10 can be further improved. If the thickness of the head 10 is equal to or less than the upper limit value, the reaching ability to the deep side of the molar teeth can be improved, and the operability in the oral cavity can be further improved.

The tufts are formed by bundling a plurality of bristles. The length from the implanted surface 11 to the tip of the bundle of bristles (bristle length) is determined in consideration of the waist of the bundle of bristles, and is, for example, 6 to 13 mm. All tufts may be of the same bristle length or may be different from one another.

The thickness of the tufts (tuft diameter) may be determined in consideration of the waist of the hair required for the tufts, and is, for example, 1 to 3 mm. All of the tufts may be of the same tuft diameter or may be different from one another.

Examples of the bristles constituting the bristle bundle include bristles (tapered bristles) having a diameter gradually decreasing toward the bristle tips and sharpened bristle tips, bristles (straight bristles) having a diameter substantially the same from the bristle surface 11 toward the bristle tips, and the like. The straight bristles include bristles having flat bristle tips substantially parallel to the bristle-implanted surface 11 and bristles having hemispherical bristle tips.

Examples of the material of the brush include polyamides such as 6-12 nylon (6-12NY) and 6-10 nylon (6-10NY), polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN) and polybutylene naphthalate (PBN), polyolefins such as polypropylene (PP), polyolefin elastomers and styrene elastomers. These resin materials may be used singly or in combination of two or more. Further, as the bristles, there may be mentioned polyester bristles having a multilayer core structure having a core portion and at least one or more sheath portions provided outside the core portion.

The cross-sectional shape of the brush is not particularly limited, and may be circular such as a perfect circle and an ellipse, polygonal, star-shaped, clover-shaped, or the like. The cross-sectional shape of all the bristles may be the same or different.

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

[ neck part 20]

From the viewpoint of operability, the length of the neck portion 20 is preferably 40mm or more and 70mm or less.

For example, the width of the neck portion 20 is formed to gradually increase from a position where the width becomes a minimum value toward the rear end side. The neck portion 20 in the present embodiment is formed to be gradually larger from the position where the width is the minimum toward the rear end side. The thickness of the neck portion 20 is formed to gradually increase from the position where the thickness is smallest toward the rear end side.

The neck portion 20 preferably has a width and a thickness of 3.0mm to 4.5mm at the position where the width and the thickness are smallest. If the width and thickness of the neck portion 20 at the minimum position are equal to or greater than the lower limit, the strength of the neck portion 20 can be further improved, and if the width and thickness are equal to or less than the upper limit, the lips are easily closed, and the reach to the molar teeth can be improved, and the operability in the oral cavity can be further improved. The width and thickness of the neck portion 20 formed to be gradually increased from the position at which the minimum value is reached toward the rear end side may be appropriately determined in consideration of the material and the like.

The front side of the neck portion 20 in a side view is inclined in a direction toward the front side as it goes toward the rear end side. The back side of the neck portion 20 in the side view is inclined in the direction toward the back side as it goes toward the rear end side. The neck portion 20 is inclined in a direction in which the distance from the center in the width direction increases toward the rear end side in the front view.

The boundary between the neck portion 20 and the grip portion 30 in the present embodiment is a position at which the increase in distance from the center in the width direction ends as the distance increases toward the rear end side in the front view. Here, the width from the neck portion 20 toward the grip portion 30 is enlarged in both front and side views by an arc-shaped contour, and coincides with the position in the longitudinal direction after the position of the curvature center of the arc is changed. More specifically, the boundary between the neck portion 20 and the grip portion 30 coincides with the position in the longitudinal direction after the curvature center changes to the rear end side outside the arc-shaped contour in the front view shown in fig. 1. In addition, the boundary between the neck portion 20 and the grip portion 30 coincides with the position in the longitudinal direction after the curvature center is changed to the rear end side outside the arc-shaped contour in the side view shown in fig. 2.

[ grip part 30]

The grip 30 is disposed along the longitudinal direction. As shown in fig. 1, the length of the grip portion 30 in the width direction gradually decreases from the boundary with the neck portion 20 toward the rear end side, and then extends at a substantially constant length. As shown in fig. 2, the length of the grip portion 30 in the thickness direction gradually narrows from the boundary with the neck portion 20 toward the rear end side, and then extends at a substantially constant length.

The length of the grip portion 30 in the width direction is the same as the position in the longitudinal direction where the length becomes substantially constant as the length gradually narrows from the boundary with the neck portion 20 toward the rear end side, and the length of the grip portion 30 in the thickness direction is the same as the position in the longitudinal direction where the length becomes substantially constant as the length gradually narrows from the boundary with the neck portion 20 toward the rear end side.

The position of the distal end of the deformable portion 70 in the axial direction in the grip portion 30 of the present embodiment is the boundary between the neck portion 20 and the grip portion 30. The position of the rear end side end portion in the longitudinal direction of the deformable portion 70 is a position which becomes substantially constant in length as gradually narrowing from the boundary with the neck portion 20 toward the rear end side, and is a boundary between the soft portion 70E and the hard portion 30H, which will be described later.

The grip portion 30 has a soft portion 31E at the center in the width direction on the front side, on the rear end side of the rear end side end portion of the deformation portion 70. The soft portion 31E constitutes a part of the soft portion E. The soft portion 31E extends in the longitudinal direction with a substantially constant width in the front view. The side edge of the soft portion 31E is formed at a substantially constant distance from the side edge on the outer side in the width direction of the grip portion 30 in the front view.

The grip portion 30 includes a hard portion 70H provided on the deformable portion 70 and a hard portion 30H provided on the rear end side of the deformable portion 70. The

hard portions

30H, 70H constitute a part of the hard portion H. The hard portion 30H has a recess 31H in which the soft portion 31E is embedded on the front surface side. The recess 31H extends in the longitudinal direction from the boundary with the deformation portion 70 toward the rear end side by a substantially constant length in front view. The soft portion 31E embedded in the recess 31H is substantially flush with the hard portion 30H exposed on the front side.

The grip portion 30 has a soft portion 32E (see fig. 1 and 2) at the center in the width direction on the back surface side. The soft portion 32E constitutes a part of the soft portion E. The soft portion 32E has an outline substantially the same as the outline of the soft portion 31E in the front view. That is, the soft portion 32E extends in the longitudinal direction with a substantially constant width in the front view. The side edge of the soft portion 32E is formed at a substantially constant distance from the side edge on the outer side in the width direction of the grip portion 30 in a rear view.

The hard portion 30H has a recess 32H (see fig. 2) in which the soft portion 32E is embedded on the back surface side. The recess 32H extends in the longitudinal direction with a substantially constant width in front view. The soft portion 32E is substantially flush with the hard portion 30H exposed on the back surface side.

Since the soft portion 31E is provided on the front side of the grip portion 30 and the soft portion 32E is provided on the rear side, the grip performance when gripping the grip portion 30 is improved.

[ deformation part 70]

Fig. 4 is a cross-sectional view of the deformation portion 70 perpendicular to the longitudinal direction, and is a cross-sectional view taken along line a-a in fig. 1.

The deformation portion 70 is deformed by an external force in a first direction perpendicular to the flocked surface 11. The deformable portion 70 has a hard portion 70H and a soft portion 70E. In the present embodiment, the periphery of the hard portion 70H is covered with the soft portion 70E.

As shown in fig. 4, the hard portion 70H is formed in a rectangular shape having a width equal to or larger than the thickness and extending in the width direction. When the width of the hard portion 70H is W and the thickness of the hard portion 70H is d, the hard portion 70H satisfies the relationship of width W > thickness d in the entire longitudinal direction. The hard portion 70H satisfies the relationship of d ≦ 3.5mm in the entire longitudinal direction.

In order to reduce the brushing pressure, it is effective to have anisotropy that is easily bent in the thickness direction and hardly bent in the width direction, but in the case where the width W of the hard portion 70H < the thickness d, the hard portion is easily bent in the width direction, and therefore, there is a possibility that an excessive brushing pressure cannot be reduced. In addition, if d > 3.5mm, the hard resin is difficult to flex, and the amount of flex before reaching an appropriate brushing pressure is small in the initial stage of the flexing behavior, so that good workability can be achieved, but the excessive brushing pressure cannot be reduced in the later stage.

By making the width W and the thickness d of the hard portion 70H satisfy the above-described relationship in the entire longitudinal direction, the hard portion 70H has a bending behavior in which it is easily bent in the thickness direction and is hardly bent in the width direction.

The center position in the thickness direction of the hard portion 70H is disposed on the rear side of the center position in the thickness direction of the deformable portion 70. That is, the hard portion 70H is disposed eccentrically toward the rear surface side in the thickness direction.

Fig. 5 is a partially enlarged front view of the hard portion 70H in the hard portion H. Fig. 6 is a side view of fig. 5.

As shown in fig. 5, the hard portion 70H is connected to the hard portion 20H of the neck portion 20 at the distal end side and connected to the hard portion 30H of the grip portion 30 at the rear end side. That is, the hard portion 70H connects the hard portion 20H of the neck portion 20 disposed on the distal end side and the hard portion 30H of the grip portion 30 disposed on the rear end side in the longitudinal direction.

The hard portion 20H connected to the hard portion 70H constitutes a rigid first region a1 having greater bending strength in the width, thickness, and thickness directions than the hard portion 70H. The hard portion 30H connected to the hard portion 70H constitutes a rigid second region a2 having greater bending strength in the width, thickness, and thickness directions than the hard portion 70H.

At least a part of a cross section of the grip 30 perpendicular to the longitudinal direction is formed of a hard resin at least from the tip of the grip 30 to the second region a2 in the longitudinal direction. In each of the first region a1 and the second region a2 of the present embodiment, the proportion of the hard resin is greater than the proportion of the soft resin in the cross section perpendicular to the longitudinal direction. For example, the first region a1 in the present embodiment has a hard resin content of 100%. The hard resin in the second region a2 accounts for about 80% or more.

At least one of the thickness and the width of the hard portion 70H gradually increases from the front end toward the rear end in the longitudinal direction, and gradually decreases through a maximum value. The hard portion 70H of the present embodiment gradually expands from the front end toward the rear end in the longitudinal direction and gradually contracts through a maximum value located at the substantial center in the longitudinal direction, in both the thickness and the width. In the deformed portion 70 of the present embodiment, the position in the longitudinal direction where the thickness shows the maximum value is the same as the position in the longitudinal direction where the width shows the maximum value.

That is, as shown in fig. 5, the hard portion 70H is formed in a substantially circular arc shape as follows: the side edges in a plan view are gradually longer from the respective ends in the longitudinal direction toward the center, and are at the maximum distance from the center in the width direction at substantially the center in the longitudinal direction. In the present embodiment, the width of the distal end of the hard portion 70H is set to be the same as the width of the rear end.

The width of the distal end of the hard portion 70H is formed smaller than the width of the rear end of the hard portion 20H of the neck portion 20, depending on the thickness of the soft portion 70E outside the hard portion 70H in the width direction. Similarly, the width of the rear end side end portion of the hard portion 70H is formed smaller than the width of the front end side end portion of the hard portion 30H in accordance with the thickness of the soft portion 70E on the outer side in the width direction than the hard portion 70H.

As shown in fig. 6, the hard portion 70H is formed in a substantially circular arc shape as follows: the side edges in a side view are gradually increased in distance from the center in the thickness direction from the respective ends in the longitudinal direction toward the center, and are maximized in distance from the center in the thickness direction at substantially the center in the longitudinal direction. In the present embodiment, the thickness of the distal end of the hard portion 70H is set to be the same as the thickness of the rear end.

The thickness of the distal end of the hard portion 70H is formed smaller than the thickness of the rear end of the hard portion 20H of the neck portion 20, depending on the thickness of the soft portion 70E on the outer side in the thickness direction than the hard portion 70H. Similarly, the thickness of the rear end side end portion of the hard portion 70H is formed smaller than the thickness of the front end side end portion of the hard portion 30H in accordance with the thickness of the soft portion 70E on the outer side in the thickness direction than the hard portion 70H.

As a material of the hard portion H, a resin having a flexural modulus of elasticity (JIS7171) of 1500MPa or more and 3500MPa or less, for example, a polyacetal resin (POM) can be given as an example. The flexural modulus of the hard portion H is more preferably 2000MPa or more and 3500MPa or less. When the flexural elastic modulus of the hard portion H is less than 1500MPa, the deformation portion 70 becomes soft, and therefore the amount of deflection before reaching an appropriate brushing pressure in the initial stage of the deflection behavior becomes large, and the workability is degraded. In addition, when the flexural elastic modulus of the hard portion H is greater than 3500MPa, the deformable portion 70 is too rigid to be bent, and it is difficult to reduce the excessive brushing pressure in the later stage of the bending behavior. Therefore, by setting the flexural elastic modulus of the hard portion H to 1500MPa or more and 3500MPa or less, good workability and reduction in brushing pressure can be achieved.

As shown in fig. 4, the soft portion 70E has a substantially hexagonal outer contour in cross section, in which the hard portion 70H is embedded. Two of the six vertexes arranged midway in the thickness direction are arranged on the center back surface side in the thickness direction with respect to the deformable portion 70 (soft portion 70E).

The occupancy rate of the cross-sectional area of the hard portion 70H with respect to the cross-sectional area of the deformed portion 70 in the cross section orthogonal to the longitudinal direction is 35% or less, preferably 25% or less, in the entire longitudinal direction. By setting the occupancy of the cross-sectional area of the hard portion 70H to 35% or less in the entire longitudinal direction, the bending strength of the deformed portion 70 toward the back surface side can be reduced.

The material of the soft portion E preferably has a shore a hardness of 90 or less, and more preferably has a shore a hardness of 40 to 80. When the shore a hardness is less than 40, the deflection amount before reaching an appropriate brushing pressure in the initial stage of the bending behavior becomes large, and the workability is deteriorated. If the shore a hardness exceeds 90, it is difficult to reduce the excessive brushing pressure at the later stage of the flexing behavior. Therefore, by setting the shore a hardness to 40 or more and 90 or less, good workability and reduction in brushing pressure can be achieved.

Examples of the soft resin include elastomers (e.g., olefin elastomers, styrene elastomers, polyester elastomers, polyurethane thermoplastic elastomers, etc.) and silicones. A styrene-based elastomer is preferable from the viewpoint of excellent miscibility with the polyacetal resin.

In the toothbrush 1, when an external force is applied to the head 10 toward the back side while the grip portion 30 is gripped, the first region a1 on the front end side and the second region a2 on the rear end side of the deformable portion 70 are rigid and do not deform because the bending strength is higher than that of the rigid portion 70H, and the deformable portion 70 disposed between the first region a1 and the second region a2 deforms.

As the deflection behavior when the deforming portion 70 is deformed, stress concentration occurs at a substantially center in the longitudinal direction in an initial stage before an appropriate brushing pressure is reached. In the latter stage of the increase in the pressure applied to the deformable portion 70, the range of the applied stress is increased from the substantially center toward both ends. Here, the deformed portion 70 has a maximum value at the center in the long axis direction of the hard portion 70H in both width and thickness, and a large cross-sectional quadratic moment, so that the deflection amount in the initial stage can be reduced. As a result, good operability can be ensured in the initial stage before the appropriate brushing pressure is reached.

In addition, since the deformed portion 70 has the smallest values at both ends in the long axis direction of the hard portion 70H in both width and thickness and the second moment of the cross section is small, the deflection amount on the end portion side becomes large at the later stage of the increase in the applied pressure, and thus the brushing can be performed with the brushing pressure reduced.

When the maximum value of the width of the hard portion 70H is e, the width of the distal end is f1, the width of the rear end is f2, and the minimum value of the widths f1 and f2 is f, the value represented by e/f is preferably 1.2 or more and 7.5 or less, and more preferably 2.0 or more and 5.0 or less. When the value represented by e/f is less than 1.2, the behavior in which the amount of deflection increases at a constant rate according to the brushing pressure is approached, and therefore, there is no initial stage and no later stage of the deflection behavior, and it is difficult to achieve both good operability and reduction in the brushing pressure. On the other hand, if the value represented by e/f exceeds 7.5, the central portion is difficult to deflect, so that the deflection starts from both end portions at an initial stage when the brush pressure is low, and the deflection amount before the appropriate load is reached becomes large. Therefore, by setting the value represented by e/f to the above range, the deflection amount before reaching an appropriate load does not become excessively large, and good operability and reduction in brushing pressure can be achieved at the same time.

The maximum value e of the width of the hard portion 70H is preferably 5.0mm or more and 15.0mm or less, and more preferably 7.0mm or more and 13.0mm or less. If the maximum value e is less than 5.0mm, the deflection amount before reaching the appropriate brushing pressure becomes large in the initial stage of the deflection behavior, and there is a possibility that the operability is deteriorated. Further, if the maximum value e exceeds 18.0mm, the central portion is less likely to deflect in the longitudinal direction in the initial stage, and therefore, in the later stage where the stress concentration progresses from the center toward both ends, there is a possibility that the brushing pressure is less likely to be reduced. Therefore, by setting the maximum value to 5.0 or more and 15.0mm or less, good operability and reduction in brushing pressure can be achieved.

The minimum value f of the width of the hard portion 70H is preferably 2.0mm or more and 8.0mm or less, and more preferably 3.0mm or more and 7.0mm or less. When the minimum value f is less than 2.0mm, the both end portions start to flex earlier than the central portion in the longitudinal direction, and therefore there is no initial stage or later stage, and it may be difficult to obtain good workability. When the minimum value f exceeds 8.0mm, both ends of the hard portion 70H are hard to bend, and therefore, the brushing pressure may be hard to decrease in the later stage. Therefore, by setting the minimum value f to 2.0mm or more and 8.0mm or less, it is possible to achieve good operability and reduction in brushing pressure.

When the maximum value of the thickness of the hard portion 70H is a, the thickness of the tip end is b1, the thickness of the rear end is b2, and the minimum value of the thicknesses b1 and b2 is b, the value represented by a/b is preferably 1.1 or more and 2.0 or less, and more preferably 1.5 or more and 2.0 or less. When the value represented by a/b is less than 1.1, the amount of deflection increases according to the brushing pressure, and therefore, there is no initial stage and late stage of the deflection behavior, and it is difficult to achieve both good operability and reduction in the brushing pressure. On the other hand, if the value represented by a/b exceeds 2.0, the central portion is difficult to deflect, so that the deflection starts from both end portions at an initial stage when the brush pressure is low, and the deflection amount before the appropriate load is reached becomes large. Therefore, by setting the value represented by a/b to the above range, the deflection amount before reaching an appropriate load does not become excessively large, and good operability and reduction in brushing pressure can be achieved at the same time.

The maximum value a of the thickness of the hard portion 70H is preferably 1.5mm or more and 3.5mm or less, and more preferably 2.0mm or more and 3.0mm or less. If the maximum value a is less than 1.5mm, the deflection amount before reaching the appropriate brushing pressure becomes large in the initial stage of the deflection behavior, and there is a possibility that the operability is deteriorated. Further, if the maximum value a exceeds 3.5mm, the central portion is less likely to deflect in the longitudinal direction in the initial stage, and therefore, in the later stage where the stress concentration progresses from the center toward both ends, there is a possibility that the brushing pressure is less likely to be reduced. Therefore, by setting the maximum value a to be 1.5mm or more and 3.5mm or less, good operability and reduction in brushing pressure can be achieved.

The minimum value b of the thickness of the hard portion 70H is preferably 1.5mm or more and 2.5mm or less, and more preferably 1.5mm or more and less than 2.0. When the minimum value b is less than 1.5mm, the both end portions start to flex earlier than the central portion in the longitudinal direction, and therefore there is no initial stage or later stage, and it may be difficult to obtain good workability. When the minimum value b exceeds 2.5mm, both ends of the hard portion 70H are hard to bend, and therefore, the brushing pressure may be hard to decrease in the later stage. Therefore, by setting the minimum value b to 1.5mm or more and 2.5mm or less, good operability and reduction in brushing pressure can be achieved.

The maximum length of the deformable portion 70 in the longitudinal direction in the front view is preferably 10% to 30%, more preferably 15% to 25% of the length of the grip portion 30 in the longitudinal direction. When the maximum length of the deformation portion 70 is less than 10% of the length of the grip portion 30, the brush pressure cannot be reduced in the later stage of the flexing behavior because the flexing is difficult. On the other hand, when the maximum length of the deforming part 70 is greater than 30% of the length of the grip part 30, the deformation is easy, and therefore the amount of deformation before reaching an appropriate brushing pressure is large, and it is difficult to achieve good operability. Therefore, by setting the maximum length of the deformation portion 70 to 10% or more and 30% or less of the length of the grip portion 30, it is possible to achieve good operability and reduction in brushing pressure.

[ 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 implemented by appropriately changing the examples without departing from the gist thereof.

(examples 1 to 8, comparative examples 1 to 5)

Samples of examples 1 to 8 were produced according to the specifications shown in [ table 1], and samples of comparative examples 1 to 5 were produced according to the specifications shown in [ table 2 ]. Comparative example 1 a toothbrush having no deformed portion was used as a sample (Clinica advanced toothbrush, manufactured by Shiwang corporation). Comparative example 2 a toothbrush in which the deformed portion was formed only of a soft resin was used as a sample. In comparative examples 3 and 4, a toothbrush having a deformed portion in which the hard portion has no maximum value and is formed with a constant width and a constant thickness was used as a sample.

[ evaluation items ]

The deflection when a load of 200g was applied to the head on the back surface side, the load on the back surface side when the deflection of the head reached 13mm, and the feeling of use were evaluated for examples 1 to 8 and comparative examples 1 to 5, respectively. Further, with respect to the sample whose deflection amount when the head was subjected to a load of 200g on the back surface side was not evaluated well, the load evaluation on the back surface side when the deflection amount of the head reached 13mm was not carried out.

[ test methods ]

For each sample, a test was performed in which a load was applied to the back surface side in the thickness direction on the flocked surface of the head. For the samples, each test was performed in units of 3 (n-3). An automatic plotter (AGS-X, manufactured by SHIMADZU Co., Ltd.) was used as an evaluation device for each test. In the load application test, the grip portion side was clamped from the boundary between the deforming portion and the grip portion so that the head portion was horizontal in side view, and the deflection when a load of 200g was applied vertically downward to each center portion of the head portion in side view (load cell: 100N, test speed 20mm/min) was measured. In the deflection application test, the load to the back surface side when the deflection amount of the head reached 13mm was measured.

[ evaluation method 1]

The amount of deflection when a load of 200g was applied to the head on the back surface side was evaluated.

O (good): 9mm to 11mm inclusive;

Δ (tolerance): more than 7mm and less than 9mm or more than 11mm and less than 13 mm;

x (bad): less than 7mm or greater than 13 mm.

Further, the load on the back surface side when the deflection amount of the head reached 13mm was evaluated.

O (good): 200g to 220g inclusive;

Δ (tolerance): more than 220g and less than 240 g;

x (bad): greater than 240 g.

-: the deflection amount when a load of 200g was applied was X, and it was not measured.

[ evaluation method of feeling of use ]

The expert group (5) performed brushing using each sample, and performed 5-stage evaluation on "the actual feeling of maintaining a moderate brushing load and reducing an excessive brushing load" in actual use, and performed evaluation on the average score thereof. The mean of the scores is the number of digits to the first place after the decimal point rounded off the second place after the decimal point.

[ Scoring ]

And 5, dividing: strong sensation, 4 points: slightly felt, 3 points: sensation neither strong nor weak, 2 points: less perceptible, 1 point: there was no sensation at all.

[ evaluation ]. very good (4.5-5.0), good. smallcircle (good): 4.0-4.5, delta (poor): 3.0-4.0, poor: (poor) < 3.0 min >

As for the evaluation results, ∈, ° Δ are defined as pass (OK), and × is defined as fail (NG).

In addition, the evaluation of the measured load was set based on a recommended value of the load when the user brushed with the toothbrush, which is generally 200 g. The deflection amount at which the upper limit of operability can be secured is set to 13mm, and the load at the deflection amount is determined based on the above evaluation.

[ TABLE 1]

[ TABLE 2]

As shown in [ Table 1], in the samples of examples 1 to 8 having the maximum thickness a and the maximum width e satisfying the relationship of W > d and d.ltoreq.3.5 mm in the entire longitudinal direction, the deflection amount when a load of 200g is applied to the head portion on the back surface side and the load when the deflection amount of the head portion reaches 13mm on the back surface side were evaluated favorably.

On the other hand, as shown in [ table 2], the sample of comparative example 1 having no deformable portion, the sample of comparative example 2 having a deformable portion formed only of a soft resin, the sample of comparative example 4 having a deformable portion formed with a constant width and a constant thickness in which the hard portion has no maximum value, and the sample of comparative example 5 having a width W of the hard portion smaller than the thickness d, were not evaluated well with respect to the deflection amount when a load of 200g was applied to the head portion toward the back surface side and the load toward the back surface side when the deflection amount of the head portion reached 13 mm. In addition, the sample of comparative example 3, which includes the deformed portion formed with a constant width and a constant thickness without having a maximum value of the hard portion, did not obtain a good evaluation of the load to the back surface side when the deflection amount of the head portion reached 13 mm.

Fig. 7 is a diagram showing a relationship between displacement and load when a load is applied to the head portion on the back surface side. As shown in fig. 7, in comparative example 1, the displacement when an appropriate brushing pressure is applied is small, and the displacement (deflection) when an excessive brushing pressure is applied to the excessive brushing pressure is hardly changed, so that it is difficult to reduce the excessive brushing pressure. On the other hand, in example 6, since the displacement when the appropriate brushing pressure is applied to the brush is large, the excessive brushing pressure can be reduced, and the brush can be performed within the range of the appropriate brushing pressure. In addition, example 6 in the figure is an example based on a simulation result calculated from the transition of the cross-sectional second moment.

While the preferred embodiments of the present invention have been described above with reference to the drawings, it goes without saying that the present invention is not limited to the above examples. The shapes, combinations, and the like of the respective constituent members shown in the above examples are examples, and various modifications can be made in accordance with design requirements and the like within a scope not departing from the gist of the present invention.

For example, in the above-described embodiment, the hard portion 70H has a structure having the maximum value and the minimum value in both the width and the thickness, but the present invention is not limited to this structure, and may have a structure having the maximum value and the minimum value in only one of the width and the thickness. In the case of this structure, the other of the width and the thickness is formed to be, for example, a constant length.

In the above embodiment, the soft portion 70E covers the periphery of the hard portion 70H over the entire circumference, but the present invention is not limited to this configuration, and a portion of the hard portion 70H may be exposed without being covered.

Industrial applicability

The invention is applicable to toothbrushes.

Description of the reference symbols

1 … toothbrush; 2 … handle body; 10 … a head; 11 … flocking surface; 20 … neck; 30 … a grip; a 70 … deformation; a1 … first region; a2 … second area; E. 31E, 32E, 70E … soft portions; H. 20H, 31H, 32H, 70H … hard portion.

Claims

1. A toothbrush, comprising: a head portion provided on a distal end side in a longitudinal direction and having a hair-setting surface; a grip portion disposed on a rear end side of the head portion; and a neck portion disposed between the bristle surface and the holding portion,

the head portion and the neck portion are formed of a hard resin,

the toothbrush has:

a deformation portion disposed on the holding portion and deformed by an external force in a first direction orthogonal to the flocked surface;

a first region which is disposed on the distal end side of the deformation portion and is not deformed by an external force in the first direction; and

a second region which is disposed on the rear end side of the deformation portion and is not deformed by an external force in the first direction,

wherein the grip portion is formed of the hard resin at least in a part of a cross section orthogonal to the longitudinal direction from at least a tip of the grip portion to the second region in the longitudinal direction,

the deformation portion has:

a hard portion formed of the hard resin and connecting the first region and the second region; and

a soft portion formed of a soft resin and covering at least a part of the hard portion,

wherein the hard portion satisfies a relationship of W > d in the entire longitudinal direction, where d is a length in the first direction and W is a length in a second direction orthogonal to the longitudinal direction and the first direction,

at least one of the length d of the hard portion in the first direction and the length W of the hard portion in the second direction is gradually increased from a front end to a rear end in the longitudinal direction, and gradually decreased from a maximum value.

2. The toothbrush of claim 1,

the hard portion satisfies d ≤ 3.5mm in the long axis direction.

3. The toothbrush of claim 1 or 2,

when the maximum value of the length d in the first direction is a and the minimum value of the end is b, the value represented by a/b is 1.1 to 2.0.

4. The toothbrush of claim 3,

the maximum value a is 1.5mm or more and 3.5mm or less.

5. The toothbrush according to any one of claims 1 to 4,

when the maximum value of the length W in the second direction is represented by e and the minimum value of the end portion is represented by f, the value represented by e/f is 1.2 to 7.5.

6. The toothbrush of claim 5,

the maximum value e is 5.0mm to 15.0mm,

the minimum value f is 2.0mm to 8.0 mm.

7. The toothbrush according to any one of claims 1 to 6,

the length of the deformation portion in the long axis direction when viewed in the first direction is 10% or more and 30% or less of the length of the grip portion in the long axis direction.