KR102589498B1 - interdental brush - Google Patents

Abstract

An interdental brush (1) including a gripping portion (2) and a brush portion (3) installed at the tip of the gripping portion (2), wherein the brush portion (3) includes an axis member (4) extending from the gripping portion (2) and An interdental brush (1) comprising a plurality of protruding pieces (5) protruding from the shaft member (4), wherein the shaft member (4) satisfies the following (A) to (C). (A) The repulsive force when a portion 5 mm from the tip of the shaft member 4 is bounced at a speed of 10 mm/sec is 0.56 N or more. (B) In a left-right bending test in which the proximal end portion of the shaft member 4 is bent 90 degrees in a first direction perpendicular to the axis line and then bent again 90 degrees in a second direction opposite to the first direction, the shaft member 4 ) The number of bendings until the core breaks is more than 20 times. (C) In a 90-degree bending test in which the proximal end portion of the shaft member 4 is bent 90 degrees in a first direction perpendicular to the axis, the maximum stress at the fifth bending is 1.7 N or more.

Description

interdental brush

The present invention relates to interdental brushes.

This application claims priority based on Japanese Patent Application No. 2015-146028, filed in Japan on July 23, 2015, the contents of which are hereby incorporated.

Interdental brushes are widely used for the purpose of efficiently cleaning the space between teeth. Interdental brushes are roughly divided into those that use metal wire as a base material and those that use synthetic resin as a base material. An interdental brush with a synthetic resin shaft provides a better feeling of contact with the gums or teeth than an interdental brush with a metal wire. For example, in Patent Document 1, a shaft member made of a core made of synthetic resin extending from the tip of the grip portion (handle portion) coated with an elastomer, and a plurality of protrusions made of an elastomer provided radially when viewed from the direction in which the shaft member extends are provided. An interdental brush is suggested.

Japanese Patent Publication No. 2013-192866

However, the synthetic resin shaft material in a conventional interdental brush has a problem in that it is not durable and breaks during use or cleaning, making it impossible to reuse.

The purpose of the present invention is to provide an interdental toothbrush that is durable enough to be reused.

[1] An interdental brush including a grip portion and a brush portion provided at the tip of the grip portion, wherein the brush portion includes a core made of a first synthetic resin extending from the grip portion, and a second synthetic resin softer than the first synthetic resin. It is provided with a shaft member made of a covering portion formed by covering a core portion, and a plurality of protruding pieces protruding from the shaft member,

The interdental brush satisfies the following (A) to (C).

(A) Shaft bending strength: The repulsion force when a portion 5 mm from the tip of the shaft member is bounced at a speed of 10 mm/sec is 0.56 N or more.

(B) Axial bending strength; bending the proximal end portion of the brush portion by 90 degrees in a first direction perpendicular to the axis line of the shaft member, returning it to its original state, and bending it by 90 degrees in a second direction opposite to the first direction, In the left and right bending test called returning to , the number of bendings in the same direction until the core part breaks is 20 or more.

(C) Repeated bending strength: When the proximal end portion of the brush portion is bent 90 degrees in a first direction perpendicular to the axis of the shaft member and bent in the same direction for the fifth time in a 90 degree bending test to return to the original. The maximum stress is 1.7N or more.

[2] The interdental brush according to [1], wherein the core part's constituent material has a bending modulus of 3.0 GPa or more as measured in accordance with ASTM D790 and a tensile elongation at break of 7.0% or more as measured in accordance with ASTM D638.

[3] The interdental brush according to [1] or [2], wherein the first synthetic resin is a composite material containing a fiber material with a fiber length of 3 μm to 300 μm and a fiber diameter of 0.1 μm to 2.0 μm.

[4] The interdental brush according to [3], wherein the fiber material contains potassium titanate fibers.

[5] The interdental brush according to any one of [1] to [4], wherein the first synthetic resin is polyester.

[6] An interdental brush made of synthetic resin having a grip portion and a brush portion provided at the tip of the grip portion, wherein the brush portion includes an shaft member extending from the tip of the grip portion and a plurality of protruding pieces protruding from the shaft member. Provided, the protruding piece protrudes radially when viewed from the extending direction of the shaft member, and the brush portion includes a region (A) formed near the rear end of the region (B), and a region ( B), wherein in the area (A), first protruding pieces of arbitrary height are arranged in the axial direction, and in the area (B), only protruding pieces that are lower in height than the first protruding pieces are arranged in the axial direction. interdental brush.

[7] The interdental brush according to [6], wherein the region (A) includes a region (A1) in which the first protruding pieces and second protruding pieces having a height lower than the first protruding pieces are arranged alternately in the axial direction. .

[8] The area B includes an area B1 on the front end side and an area B2 on a rear end side than the area B1, and the area B2 includes a section equal to or less than the second protruding piece. Only the fourth protruding piece in height is arranged in the axial direction, the protruding piece in the region B1 has a height equal to or less than the fourth protruding piece, and the region B1 has a height higher than the fourth protruding piece. The interdental brush described in [7], comprising a low third protruding piece.

[9] The interdental brush according to any one of [6] to [8], wherein in the region A, the axial distance between the first protruding pieces increases toward the tip.

[10] The interdental toothbrush according to any one of [6] to [9], wherein an enlarged portion whose diameter expands from the front end toward the rear end is formed near the brush portion of the grip portion.

(Effects of the Invention)

Since the interdental toothbrush of the present invention is excellent in durability, it is suppressed from bending during use and can be washed and used repeatedly.

1 is a plan view showing the interdental brush 1 of the first embodiment of the present invention.
Figure 2 is an enlarged plan view of the brush portion 3 of the interdental brush 1 of Figure 1.
Figure 3 is a sectional view II of the interdental brush 1 of Figure 2.
Figure 4 is a top view of the primary product (aircraft) 10.
Figure 5 is an enlarged cross-sectional view of the tip of another example of the interdental brush of the present invention.
Figure 6 is an enlarged plan view of the brush portion 3 of the interdental brush 1 of Figure 1.

The definitions of terms below apply throughout the scope of this specification and claims.

“Soft resin” means a resin with a Shore A hardness of 90 or less as measured in accordance with JIS K 7215.

“Hard resin” refers to a resin whose Shore A hardness is higher than that of a soft resin, that is, a resin whose Shore A hardness is greater than 90.

《First Form》

The interdental brush of the first aspect of the present invention is an interdental brush having a grip portion and a brush portion provided at the tip of the grip portion.

The brush portion includes a shaft made of a core made of a first synthetic resin extending from the grip portion and a covering portion formed by covering the core with a second synthetic resin softer than the first synthetic resin, and a plurality of protruding pieces protruding from the shaft. Equipped with

Hereinafter, an example of the interdental brush of the first form of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the interdental brush 1 of the first embodiment of the present invention includes a grip portion 2 made of a hard resin (first synthetic resin) whose diameter is gradually reduced toward the tip side, and the grip portion 2 It is provided with a brush portion (3) extending from the tip of.

As shown in FIG. 2, the brush portion 3 includes a shaft member 4 extending from the tip of the gripping portion 2, and a plurality of protruding pieces 5a to 5d (5) forming a brush material protruding from the shaft member 4. )) is provided.

As shown in FIG. 3, the shaft member 4 has a core portion 4a mainly made of hard resin (first synthetic resin) extending from the tip of the gripping portion 2, and a soft resin (second resin) covering the core portion 4a. and a covering portion 4b made of synthetic resin. The protruding piece 5, which protrudes radially when viewed from the axis of the shaft member 4, is made of soft resin and is formed integrally with the covering portion 4b.

<Grip part>

The gripping portion 2 is a member for gripping with fingers. The shape of the gripping portion 2 of this embodiment is not particularly limited as long as it is a shape that can be gripped with the fingers, and examples include pillar shapes such as plate shape, cylinder shape, triangular pillar shape, and square pillar shape.

For the purpose of making it easier to hold the gripping part 2 with the fingers, for example, the gripping part 2 may be formed with irregularities, holes, through-holes, curves, etc.

The gripping portion 2 is formed with a reduced diameter portion 2a whose diameter decreases toward the distal end, and a brush portion 3 is provided at the distal end of the reduced diameter portion 2a.

If the reduced diameter portion 2a is formed, it becomes easy to visually recognize the state of the brush portion 3 in the interdental space when using the interdental brush 1 while checking with a mirror. In addition, since the reduced diameter portion 2a is gradually enlarged toward the handle, insertion into the interdental can easily stop at the reduced diameter portion 2a, thereby preventing excessive insertion of the interdental toothbrush 1.

The range of the minimum diameter to the maximum diameter of the reduced diameter portion 2a is not particularly limited, and for example, 1 mm to 5 mm is preferable, 1.5 mm to 5 mm is more preferable, and 1.5 mm to 4 mm is still more preferable.

If the minimum diameter is greater than or equal to the lower limit of the range, structural strength can be increased.

If the maximum diameter is below the upper limit of the range, handling within the premises becomes easy.

The diameter of the reduced diameter portion 2a is the diameter of the cross section perpendicular to the axial diameter direction (longitudinal direction of the brush portion). When the cross-section is not circular, for example, a rectangle, oval, or other polygon, the diameter of the smallest circle including the cross-sectional shape is taken as the diameter of the reduced diameter portion 2a.

In the example of Fig. 1, the minimum diameter of the reduced diameter portion 2a is the diameter at the position indicated by symbol “3a”. The position is the boundary between the brush portion 3 and the reduced diameter portion 2a. Here, the symbol “3a” is used as a symbol representing the base end of the brush portion 3 for convenience. Additionally, the maximum diameter of the reduced diameter portion 2a is equal to the diameter R1 of the grip portion 2. Additionally, the minimum and maximum diameters of the reduced diameter portion 2a do not include the thickness of the soft resin layer 6.

The width or diameter (thickness) R1 of the gripping portion 2 is not particularly limited, and is preferably 5 mm to 10 mm, for example.

If the width or diameter is greater than or equal to the lower limit of the range, structural strength can be increased.

If the width or diameter is below the upper limit of the range, handling during cleaning of the premises becomes easy.

The constituent material of the gripping portion 2 is not particularly limited, and known materials constituting the gripping portion of a conventional interdental toothbrush can be applied. The constituent material of the gripping portion 2 is preferably synthetic resin, and from the viewpoint of enhancing the unity with the shaft member 4 extending from the tip of the gripping portion 2, the core portion 4a of the shaft member 4, which will be described in detail later, ) is preferably the same as the constituent materials. In this embodiment, it is preferable that the grip portion and the shaft member are formed integrally.

The constituent material of the gripping portion 2 may be one type, or may be a composite material containing two or more types.

<Brush part>

As shown in Fig. 2, the brush portion 3 is provided with a shaft member 4 extending from the tip of the reduced diameter portion 2a of the grip portion 2 (proximal end 3a of the brush portion 3). A plurality of first protruding pieces 5a to fourth protruding pieces 5d of various lengths protrude radially perpendicular to the axis of the shaft member 4. Each protruding piece is formed by a portion of the soft resin forming the covering portion 4b of the shaft member 4 protruding from the surface of the covering portion 4b on the core portion 4a.

The soft resin covering the shaft member 4 extends from the base end 3a of the brush portion 3 onto the reduced diameter portion 2a, forming a soft resin layer 6 that covers a portion of the reduced diameter portion 2a. I'm doing it.

The shape of the shaft member 4 is not particularly limited as long as a plurality of protruding pieces 5 can be installed and can be inserted between teeth. For example, it may be column-shaped, triangular-column, square-column, etc., or plate-shaped. Shapes such as:

In the example of this embodiment, the shape of the shaft member 4 is a cylinder shape (that is, a truncated cone) whose diameter decreases toward the tip. Accordingly, it becomes easier to insert the brush portion 3 between teeth.

The length of the shaft member 4 is preferably 10 mm or more, and in order to increase the cleaning efficiency between teeth, 12 mm or more is more preferable, and 13 mm or more is still more preferable.

The upper limit of the length of the shaft member 4 is not particularly limited, and for example, it is preferable if it is 20 mm or less because operability within the premises increases. Therefore, the length of the shaft member 4 is preferably 10 to 20 mm, more preferably 12 to 20 mm, and even more preferably 13 to 20 mm.

The thickness of the shaft member 4 is not particularly limited, and for example, the area of the cross section perpendicular to the longitudinal direction at 0.1 mm from the tip of the shaft member 4 is preferably 0.010 mm2 to 1.500 mm2, more preferably 0.030 mm2. The thickness is preferably ㎟ to 1.200 ㎟, more preferably 0.060 ㎟ to 0.800 ㎟. In addition, the area of the cross section perpendicular to the longitudinal direction of the proximal end portion of the shaft member 4 is preferably 0.200 mm2 to 3.140 mm2, more preferably 0.380 mm2 to 2.540 mm2, and even more preferably 0.500 mm2 to 1.770 mm2. desirable.

If the area of the cross section is more than the above lower limit, the rigidity of the shaft member 4 can be further increased.

If the area of the cross-section is below the upper limit, it becomes easier to insert the shaft member 4 into narrow interdental spaces, and cleaning power can be increased.

The thickness of the shaft member 4 from the base end to the tip may be constant, or it may have a tapered shape that reduces or enlarges the diameter as it moves toward the tip. In the case of a tapered shape, the angle (taper angle) formed by the surface of the shaft member 4 with respect to the axis line of the shaft member 4 is not particularly limited and may be constant or may change gradually or stepwise.

[Strength of shaft]

The shaft member 4 of the interdental brush 1 satisfies the following (A) to (C).

(A) Shaft bending strength: When the gripping portion 2 is fixed and a portion 5 mm from the tip of the shaft member 4 is bounced at a speed of 10 mm/sec, the repulsive force is 0.56 N or more.

(B) Shaft bending strength: bending the proximal end portion of the brush portion 3 by 90 degrees in a first direction orthogonal to the axis of the shaft member, returning it to its original state, and bending it by 90 degrees in a second direction opposite to the first direction. In the left and right bending test to return it to its original state, the number of times it is bent in the same direction until the core portion 4a is fractured is 20 or more.

(C) Repeated bending strength: The proximal end portion of the brush portion 3 is bent 90 degrees in a first direction perpendicular to the axis of the shaft member, and bent 5 times in the same direction in a 90-degree bending test to return to the original. The maximum stress when doing this is over 1.7N.

(A) Shaft bending strength is measured in the following test.

The center of the grip part 2 of the interdental brush 1 is fixed by any means, for example a jig, and moved at 10 mm/sec at a distance of 5 mm from the tip of the brush part 3 of the interdental brush 1. The friction element is slid and the resistance value (unit: N) when bounced is measured using a device used in the ISO 8627 method (toothbrush hardness standard). At this time, it is measured so that the grinder does not close to the area on the gripping part 2 side more than 5 mm from the tip of the brush part 3.

(B) Axial bending strength is measured by the following left and right bending test.

First, the entire brush part 3 except the base end 3a of the brush part 3 of the interdental brush 1 is fixed by any means, for example, a jig, and a gap of 5 mm is left from the fixed part, and the The branch (2) side was pinched with a chuck. Accordingly, there is an unfixed area (exposed area) of 5 mm between the jig and the chuck.

This unfixed area is a portion including the proximal end 3a of the brush portion 3 (proximal end portion of the brush portion 3). Here, the base end 3a of the brush portion 3 is the lower end on the gripping portion 2 side of the protruding piece 5 closest to the gripping portion 2 side installed on the brush portion 3, that is, the protruding piece provided in rows. It is the periphery of (5).

The proximal end portion of the brush portion 3 is bent 90 degrees in the first direction perpendicular to the axis of the shaft member 4 and returned to its original state. (That is, the brush portion 3 is bent 90 degrees at the proximal end portion. , returns to the original state.) Here, the first direction may be the left direction when viewed in the axis direction along which the shaft member 4 extends, for example, when viewed in the ground depth direction of FIG. 3.

Subsequently, the base portion is bent 90 degrees in a second direction opposite to the first direction and returned to its original state.

Here, the second direction is the opposite direction from the first direction and is a direction perpendicular to the axis of the shaft member 4, for example, the right direction when viewed from the ground depth direction (axial direction) in FIG. 3. You can. This set of left and right bending is counted as the number of bending times in this test.

The bending of the left and right sets is repeated in the same direction (in the same first and second directions) at 30 rpm (a speed of 30 times per minute), and the number of times until the core portion 4a of the shaft member 4 is fractured is measured. . It is judged with the naked eye that the core portion 4a of the shaft member 4 is fractured. After the core portion 4a of the shaft member 4 is broken, there are cases where the tip side where the brush portion 3 is bent and the proximal end side (grip portion 2 side) are still connected by the covering portion 4b. In this case, it can be seen that the force required for bending was extremely reduced, resulting in fracture. Additionally, by peeling off the covering portion 4b and visually confirming that the core portion 4a is fractured, it can be confirmed that the above judgment was correct.

Additionally, an interdental brush that breaks during the 20th bending before the 20th bending is completed is considered to have broken less than 20 times.

(C) Repeated bending strength is measured by the following 90 degree bending test.

First, the center of the grip portion 2 of the interdental brush 1 is fixed by any means, for example, a jig, and the pressing tool is brought into contact with the base end 3a of the brush portion 3 of the interdental brush 1. . Here, the position of the base end 3a of the brush portion 3 is the same as in the case of (B) axis bending strength. Subsequently, the tip side from the base end 3a of the brush portion 3 is bent by 90 degrees in a first direction perpendicular to the axis of the shaft member 4 using a pressing tool, and returned to its original state. Here, the first direction may be the left direction when viewed in the axis direction along which the shaft member 4 extends, for example, when viewed in the ground depth direction of FIG. 3. This 90-degree bending is counted as the number of bending times in this test.

The left and right bending is repeated four times in the same direction (in the same first direction), and the maximum stress at the fifth bending in the same direction is measured using a push-pull gauge. Each round of bending is performed at a compression speed of 80 mm/sec. The push-pull gauge is performed using, for example, the popular digital force gauge D2D manufactured by Imada.

(A) The axis bending strength is 0.56 N or more, preferably 0.60 N or more, more preferably 0.65 N or more, and still more preferably 0.70 N or more.

If it is above the lower limit, the brush portion 3 of the interdental toothbrush 1 has appropriate rigidity, so insertion and removal between teeth can be easily performed. The upper limit is not particularly limited, and examples include 1.00N or less. Therefore, the axial bending strength is preferably, for example, 0.56 to 1.00 N, more preferably 0.60 to 1.00 N, further preferably 0.65 to 1.00 N, and especially preferably 0.70 to 1.00 N.

The shaft bending strength is controlled by a combination of the type of synthetic resin constituting the shaft member 4, the type and amount of the fiber material, and the thickness of the base end of the shaft member 4 (base end 3a of the brush portion 3).

(B) The axial bending strength is 20 times or more, preferably 100 times or more, more preferably 150 times or more, and still more preferably 200 times or more.

If it is above the lower limit, it is difficult to break even if the brush portion 3 is temporarily bent during use or when cleaning the brush, and durability is excellent. The upper limit is not particularly limited, but for example, less than 10,000 times is appropriate.

The shaft bending strength is adjusted by a combination of the type of synthetic resin constituting the shaft member 4, the type and amount of the fiber material, and the thickness of the base end of the shaft member 4 (base end 3a of the brush portion 3).

(C) The repeated bending strength is 1.70N or more, preferably 1.75N or more, more preferably 1.80N or more, and still more preferably 1.85N or more.

If it is above the lower limit, after the brush portion 3 is bent during use or cleaning the brush, it can be returned to its original state and used again, and durability is excellent. The upper limit is not particularly limited, and examples include 2.50 N or less. Therefore, the cyclic bending strength is preferably, for example, 1.70 to 2.50 N, more preferably 1.75 to 2.50 N, further preferably 1.80 to 2.50 N, and especially preferably 1.85 to 2.50 N.

The repeated bending strength is adjusted by a combination of the type of synthetic resin constituting the shaft member 4, the type and amount of the fiber material, and the thickness of the base end of the shaft member 4 (base end 3a of the brush portion 3).

[Heart of Accumulation]

The constituent material of the core portion 4a of the shaft member 4 is not particularly limited, and from the viewpoint of realizing the strength of the above (A) to (C), it is preferable that it contains synthetic resin as the main material.

The synthetic resin is preferably at least one of a hard resin and a soft resin, and more preferably a hard resin.

The content of the synthetic resin is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, and even more preferably 70 to 100% by mass, relative to the total mass of the core portion 4a of the shaft member 4.

The content of the hard resin is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, and still more preferably 70 to 100% by mass, relative to the total mass of the core portion 4a of the shaft member 4.

The number of the above synthetic resins may be one, and two or more types may be used.

The type of the hard resin is not particularly limited, and known hard resins can be applied. For example, a resin with a bending elastic modulus (JIS K7203) in the range of 500 to 3000 MPa can be used.

Examples of such hard resins include polypropylene (PP), polytrimethylene terephthalate (PTT), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexylenedimethylene terephthalate (PCT), Examples include polyacetal (POM), polystyrene (PS), acrylonitrile butadiene styrene resin (ABS), cellulose propionate (CP), polyarylate, polycarbonate, and acrylonitrile styrene copolymer resin (AS). . Among these, polyester, which has good adhesion to the soft resin constituting the covering portion 4b, is preferable, and PTT and PBT are more preferable.

Any component other than the synthetic resin used as the main material may be added to the constituent material of the core portion 4a of the shaft member 4. Preferred optional components include, for example, fillers made of inorganic materials and/or organic materials. By adding filler to the synthetic resin as a constituent material of the core portion 4a, the strength of the core portion 4a (A) to (C) can be improved.

The constituent materials of the filler are not particularly limited, and examples include inorganic materials such as glass, ceramics, minerals, and carbon materials, and organic materials such as synthetic resins.

The synthetic resin constituting the filler may be the same as or different from the synthetic resin constituting the core portion 4a of the shaft member 4. Preferred synthetic resins include polyamides such as aramid and nylon.

Examples of carbon materials constituting the filler include carbon particles such as carbon black, carbon nanotubes, fullerene, and graphene.

Examples of minerals and ceramics constituting the filler include mica, talc, silicon carbide, and titanium oxide compounds.

The shape of the filler is not particularly limited, and may be any shape such as fibrous, granular, or plate-like, and the fibrous shape is preferable because the strength of the above (A) to (C) can be easily improved.

The fiber length of the fibrous filler is not particularly limited, and for example, it is preferably 3 μm to 300 μm, more preferably 6 μm to 100 μm, and even more preferably 9 μm to 50 μm.

If the fiber length is more than the above lower limit, the rigidity of the core portion 4a of the shaft member 4 can be further increased.

If the fiber length is below the above upper limit, the toughness of the core portion 4a of the shaft member 4 can be further improved.

Here, the fiber length is the arithmetic average of the fiber lengths of 100 fibrous fillers (length from the front end to the rear end in the longitudinal direction of the fiber). Therefore, the fiber length can also be referred to as the average fiber length. The fiber length of the fibrous filler is measured by electron microscopic observation.

The fiber diameter of the fibrous filler is not particularly limited, and for example, it is preferably 0.1 μm to 2.0 μm, more preferably 0.2 μm to 1.0 μm, and even more preferably 0.3 μm to 0.8 μm.

If the fiber diameter is more than the above lower limit, the rigidity of the core portion 4a of the shaft member 4 can be further increased.

If the fiber diameter is below the above upper limit, the toughness of the core portion 4a of the shaft member 4 can be further improved.

Here, the fiber diameter is the arithmetic average of the fiber diameters (the longest length in the direction perpendicular to the longitudinal direction of the fiber) of 100 fibrous fillers. Therefore, the fiber diameter can be said to be the average fiber diameter. The fiber diameter of the fibrous filler is measured by electron microscope observation.

The content of the filler relative to the total mass of the core portion 4a of the shaft member 4 is not particularly limited, and for example, 5 to 29 mass% is preferable, 10 to 25 mass% is more preferable, and 15 to 20 mass%. % is more preferable.

If the content is more than the lower limit, the rigidity of the core portion 4a of the shaft member 4 can be further increased.

If the content is below the upper limit, the toughness of the core portion 4a of the shaft material 4 can be further improved.

The core portion 4a of the shaft member 4 preferably contains a fiber material having a fiber length of 3 μm to 300 μm and a fiber diameter of 0.1 μm to 2.0 μm as an optional filler along with the synthetic resin as the main material.

As the fiber material, potassium titanate fibers represented by the chemical formula K ₂ Ti ₈ O ₁₇ or K ₂ Ti ₆ O ₁₃ are particularly preferable. Such potassium titanate fibers are commercially available, and examples include TISMO (registered trademark) manufactured by Otsuka Chemical Co., Ltd.

The bending elastic modulus of the constituent material of the core portion 4a, measured in accordance with ASTM D790 (3-point load, method A), is preferably 3.0 GPa or more from the viewpoint of realizing the strengths of (A) to (C) above, and is 4.0 GPa. More is more preferable, and 5.0 GPa or more is more preferable. The upper limit is not particularly limited, and for example, 20 GPa or less is appropriate.

The tensile elongation at break of the constituent material of the core portion 4a measured in accordance with ASTM D638 is preferably 7.0% or more, more preferably 8.0% or more, and 10.0% from the viewpoint of realizing the strengths of (A) to (C) above. % or more is more preferable. The upper limit is not particularly limited, and for example, 30% or less is appropriate.

As a preferable combination of the bending elastic modulus and tensile elongation at break of the constituent materials of the core portion 4a, any combination of the preferable ranges exemplified above can be mentioned. Specifically, for example, if expressed in the form of (value of bending elastic modulus) and (value of tensile elongation at break), it is 3.0 GPa or more, 7.0% or more, 3.0 GPa or more, 8.0% or more, 3.0 GPa or more, and 10.0. % or more, 4.0 GPa or more, and also 7.0% or more, 4.0 GPa or more, and also 8.0% or more, 4.0 GPa or more, and also 10.0% or more, 5.0 GPa or more, and also 7.0% or more, 5.0 GPa or more, and also 8.0% or more, 5.0 GPa or more Combinations of the above and 10.0% or more may also be mentioned. Among these, the strengths of (A) to (C) above can be easily achieved by using constituent materials with a bending elastic modulus of 3.0 GPa or more and a tensile elongation at break of 7.0% or more.

The constituent material of the core portion 4a is preferably a composite material containing a filler and a synthetic resin from the viewpoint of more easily realizing the strengths of (A) to (C) above.

[Coating part of stock material]

The constituent material of the covering portion 4b of the shaft member 4 is not particularly limited, and soft resin is preferable. If the covering portion 4b is molded from soft resin, it is difficult to damage the gums or teeth when inserting the brush portion 3 between teeth, and the touch feeling is improved.

The shore hardness A (Shore A hardness) of the soft resin constituting the covering portion 4b is preferably A90 or lower, and more preferably A30 to A80. Preferred soft resins include known elastomer resins such as polyolefin-based elastomers, styrene-based elastomers, and polyester-based elastomers.

The soft resin constituting the covering portion 4b may be of one type, or may be of two or more types.

The covering portion 4b may cover the entire brush portion 3 or only a portion of the brush portion 3.

The thickness of the covering portion 4b is not particularly limited, and for example, it is preferably 0.1 mm to 1.0 mm, more preferably 0.1 mm to 0.5 mm, and even more preferably 0.1 mm to 0.3 mm.

If the thickness of the covering portion 4b is greater than the lower limit, the protruding piece 5 can be prevented from falling off from the covering portion 4b and the structural strength of the brush portion 3 can be increased.

If the thickness of the coating portion 4b is below the upper limit, the overall diameter of the brush portion 3 can be suppressed from becoming too thick, and insertion into narrow interdental spaces can be improved.

As a method of measuring the thickness of the covering portion 4b, for example, in the brush portion 3, three or more locations are arbitrarily selected between two adjacent protruding pieces 5 and the thickness of the soft resin at each location is measured using a microscope or magnifying glass. One way to obtain it is as the arithmetic mean of the measured value.

[Extrusion]

The shape or size of the protruding piece 5 radially protruding from the shaft member 4 when viewed from the axis direction along which the shaft member 4 extends is not particularly limited. As shown in FIG. 2, the brush portion 3 of the interdental brush 1 of the present embodiment has first to fourth protruding pieces 5a to 5d having different heights from the surface of the shaft member 4. There are multiple installations. These protruding pieces 5 are responsible for cleaning between teeth and function as a brush material to scrape off tartar.

The height of the protruding piece 5 is not particularly limited, and for example, 0.1 mm to 2.5 mm is preferable, 0.3 mm to 1.8 mm is more preferable, and 0.6 mm to 1.2 mm is still more preferable. Here, the height of the protruding piece 5 means the length from the base end on the surface side of the covering portion 4b to the tip.

If the height of the protruding piece 5 is more than the lower limit, high cleaning power can easily be obtained.

If the height of the protruding piece 5 is below the upper limit, it becomes easy to insert the brush portion 3 between teeth.

The relative heights of the plurality of protruding pieces 5 are not particularly limited and may be the same or different from each other.

The thickness (thickness) of the protruding piece 5 is not particularly limited, and for example, 0.1 mm to 1.5 mm is preferable, 0.1 mm to 0.5 mm is more preferable, and 0.1 mm to 0.2 mm is still more preferable. Here, the thickness of the protruding piece 5 means the largest diameter of the cross section perpendicular to the direction in which the protruding piece 5 protrudes.

If the thickness of the protruding piece 5 is more than the lower limit, it can be easily formed by injection molding, and the rigidity necessary for scraping off dental calculus can easily be obtained.

If the thickness of the protruding piece 5 is below the upper limit, it becomes easy to insert the brush portion 3 between teeth.

The relative thickness of the plurality of protruding pieces 5 is not particularly limited and may be the same or different from each other.

In the interdental brush 1 shown in Fig. 3, the protruding pieces 5 are formed to protrude radially in four directions at equal intervals of 90° around the axis of the shaft member 4.

The number of protruding pieces 5 that protrude radially when viewed from the direction in which the shaft member 4 extends is not particularly limited, and for example, it is preferable that 2 to 6 protrude radially at equal intervals around the shaft.

The shape seen from the front of the protruding piece 5 when viewed from the extending direction of the shaft member 4 is not particularly limited. For example, as shown in FIG. 3, the height direction from the shaft member 4 is longer than the width direction and is rectangular. The corners on both sides of the tip may have a round shape. Other shapes seen from the front include, for example, a trapezoidal shape, a square shape, a rectangular shape, and a substantially oval shape whose width narrows toward the tip.

The distance between adjacent protruding pieces 5 when viewed in the axial direction along which the shaft member 4 constituting the brush portion 3 extends is not particularly limited, and is preferably 0.3 mm to 0.8 mm, for example.

If the distance is more than the lower limit, it becomes easy for each protruding piece 5 to function independently.

If the distance is below the upper limit, it is easy to maintain tartar between each protruding piece, and high cleaning power is easy to be obtained.

The total number of the protruding pieces 5 arranged in the brush portion 3 in the axial direction along which the shaft member 4 extends is not particularly limited, and for example, it is preferably 10 to 100, more preferably 20 to 50. .

If the total number is more than the lower limit, sufficient cleaning power can be easily obtained.

If the total number is below the upper limit, both insertion and removal between teeth becomes easy, and the workability of cleaning between teeth increases.

<Manufacturing method>

The manufacturing method of the interdental brush of the present invention is not particularly limited, and a known manufacturing method can be applied. For example, by injection molding using a mold, first, a primary product (base) 10 is obtained in which the core portion 4a and the grip portion 2 of the shaft member 4 are integrally molded (see Fig. 4). Subsequently, a part of the core portion 4a and the reduced diameter portion 2a is covered with a soft resin, and the brush portion 3 is formed by integrally molding the coating portion 4b and the protruding piece 5, A portion of the reduced diameter portion 2a is covered with the soft resin layer 6 (see Fig. 1). The interdental brush 1 can be manufactured by such known injection molding.

In preparing the composite material constituting the shaft 4, when mixing arbitrary components such as filler with synthetic resin, the mixing method is not particularly limited, and examples include stirrer, stirrer, ball mill, magnetic rotation mixer, A known method using an ultrasonic disperser or the like is applied.

<Action effect>

Since the shaft material constituting the brush portion of the interdental brush of the present invention satisfies the above-mentioned (A) to (C), it is excellent in durability, is suppressed from bending during use, and can be washed and used repeatedly.

Since at least the brush part of the interdental brush of the present invention is made of synthetic resin, it is difficult to feel pain even when touching the gums, etc., and the touch feeling is good compared to a conventional interdental brush provided with a metal wire.

<Other embodiments>

The interdental brush of the present invention is not limited to the interdental brush 1 of the first embodiment described above.

For example, as shown in Fig. 5, there is an interdental toothbrush in which the tip 4c of the shaft member 4 is spherical. According to the interdental brush, pain when the distal end 4c of the shaft member 4 touches the gums is further reduced, and a more comfortable touching feeling is obtained. The spherical tip portion 4c is preferably formed of soft resin.

《Second Form》

The interdental brush of the second aspect of the present invention is an interdental brush made of synthetic resin having a grip portion and a brush portion provided at the tip of the grip portion. Hereinafter, an example of the interdental brush of the present invention will be described in detail with reference to the drawings.

The shape of the second type of interdental brush can be explained with reference to FIGS. 1 to 5 used in the description of the first type of interdental brush. For this reason, in the following description, with reference to FIGS. 1 to 6, members common to the first embodiment are given the same symbols.

The interdental brush 1 of the second type is made of synthetic resin and, as shown in FIG. 1, has a grip portion 2 and a brush portion 3 provided at the tip of the grip portion 2.

(grip part)

The gripping portion 2 is a column-shaped member for gripping with fingers.

The shape of the gripping portion 2 is a flat plate shape in this example.

Additionally, the shape of the gripping portion 2 may be any shape that can be gripped with a finger, and in addition to the above-mentioned flat plate shape, a cylindrical shape, (triangular pillar shape, square pillar shape, etc.), etc. may be adopted.

In the gripping portion 2 of this example, an enlarged diameter portion 2a is formed near the brush portion 3, which expands in diameter from the front end toward the rear end. Accordingly, even if the interdental toothbrush (1) is accidentally pushed strongly in the axial direction with the brush portion (3) inserted between the teeth, the interdental insertion stops at the enlarged diameter portion (2a), so the interdental brush (1) It is easy to prevent damage to the oral cavity.

The material forming the grip portion 2 is not particularly limited, and known materials forming the grip portion of an interdental toothbrush can be used, for example, materials such as those listed for the shaft material 4 described later. .

The material forming the grip portion 2 may be of one type, or may be of two or more types.

(Brush part)

The brush portion 3 has a shaft member 4 extending from the tip of the grip portion 2, and first to fourth protruding pieces 5a to 5d protruding from the shaft member 4. The first protruding pieces 5a to the fourth protruding pieces 5d are formed integrally with the covering portion 4b of the shaft member 4, which will be described later.

The shaft member 4 is a column-shaped member extending from the tip of the gripping portion 2. As the shaft member 4, a cylindrical shape, a triangular pillar shape, a square pillar shape, etc. may be employed. Additionally, the shaft member 4 may be reduced in diameter toward the tip, and may form, for example, a truncated cone. Accordingly, it becomes easier to insert the brush portion 3 between teeth.

As shown in Fig. 3, the shaft member 4 has a core portion 4a extending from the tip of the grip portion 2 and a covering portion 4b that covers the surface of the core portion 4a.

As a material for forming the shaft member 4, hard resin is preferable, and among these, a resin having a bending elastic modulus of 500 to 3000 MPa measured in accordance with JIS K7203 is preferable. Specific examples are the same as above.

Soft resin is preferable as a material for forming the covering portion 4b. By forming the covering portion 4b with soft resin, it is less likely to damage the gums or the like when inserting the brush portion 3 between teeth, and the touch feeling is improved.

Examples of soft resins include elastomer resins such as polyolefin-based elastomers, styrene-based elastomers, and polyester-based elastomers.

The thickness of the covering portion 4b is preferably 0.1 to 0.5 mm, and more preferably 0.1 to 0.3 mm. If the thickness of the covering portion 4b is more than the lower limit, it is easy to fill the soft resin up to the tip of the protruding piece. If the thickness of the covering portion 4b is below the upper limit, insertion between teeth can be improved. The method of measuring the thickness of the covering portion 4b is as described above.

As shown in FIG. 6, the brush portion 3 includes a region (A) 14 formed near the rear end of the region (B) 17, and a region (B) formed near the front end of the region (A) 14. 17) is included. Area (A) 14 includes area (A1) 12 on the front end side and area (A2) 13 on the rear end side from area A1 (12). Area (B) 17 includes area (B1) 15 at the front end and area (B2) 16 at the rear end of area (B1) 15. In this way, the area (B1) (15), area (B2) (16), area (A1) (12) and area (A2) (13) are formed in this order from the front end to the rear end of the brush portion (3). there is.

[Area (A)]

Area (A) 14 is an area of the brush unit 3 that greatly contributes to the development of cleaning power between teeth.

In the area (A) 14, a plurality of first protruding pieces 5a of arbitrary height are arranged in the axial direction. In the area (A1) (12) on the tip side of the area (A) (14), a first protruding piece (5a) of an arbitrary height and a second protruding piece (5a) of a lower height than the first protruding piece (5a). (5b) are arranged alternately in the axial direction. In the area A2 (13) on the rear end side, only the first protruding pieces 5a of arbitrary height are arranged in the axial direction.

When area A is comprised of area A1 and area A2, the boundary between area A1 and area A2 in the axial direction of the shaft material is determined so that area A2 is widest. Specifically, in this example, the area A1 (12) is an area from the second protruding piece 5b on the rearmost side to the first protruding piece 5a on the frontmost side. The area (A2) 13 is an area from the first protruding piece 5a located next to the rearmost second protruding piece 5b to the rearmost first protruding piece 5a. .

<First Projection>

The first protruding piece 5a is a plate-shaped member for scraping off tartar, etc., existing between teeth. The plate-shaped protruding pieces are highly effective in scraping off tartar, etc.

As shown in FIG. 3, the first protruding piece 5a is viewed from the direction of extension of the shaft member 4 so that the flat portion of the first protruding piece 5a (projection piece 5) is perpendicular to the axial direction of the shaft member 4. It is installed so that it protrudes radially. In the example of FIG. 3, when viewed from the direction in which the shaft member 4 extends, first protruding pieces 5a are formed in four directions at 90° intervals around the axis of the shaft member 4. That is, in the plane perpendicular to the shaft member 4, four first protruding pieces 5a are formed to protrude in the X-axis direction and the Y-axis direction orthogonal to the X-axis direction, respectively. It is preferable that the first protruding pieces 5a are formed at equal intervals around the axis of the shaft member 4 in this way.

The number of first protruding pieces 5a radially protruding when viewed from the direction of extension of the shaft member 4 is four in the example of FIG. 3, but is not limited to four, and may be three or less, or five or more. It's okay to continue. It is preferable that at least two first protruding pieces 5a protrude radially when viewed from the direction in which the shaft member 4 extends.

A plurality of first protruding pieces 5a that protrude radially when viewed from the extending direction of the shaft member 4 are formed at equal intervals from each other, and the center line of each first protruding piece 5a is aligned with the center of the shaft member 4. It is desirable that the angles formed by the connecting lines are all formed the same. Meanwhile, the plurality of first protruding pieces 5a are formed at unequal intervals from each other, and the angles formed by the line connecting the center of each first protruding piece 5a and the center of the shaft member 4 are formed to be different from each other. It doesn't matter even if it is done.

The shape of the first protruding piece 5a in the example of FIG. 3 when viewed from the front is rectangular in the height direction from the shaft member 4 longer than the width direction, and the corners on both sides of the distal end are rounded. In addition, the shape of the first protruding piece 5a when viewed from the front is not limited to that of the present embodiment, for example, a trapezoidal shape, a square shape, a rectangular shape, or a roughly razor-shaped shape whose width narrows toward the tip. It may be in its original form, etc.

The first protruding piece 5a has the highest height from the shaft member 4 among the protruding pieces formed on the brush portion 3. High cleaning power is achieved by the first protruding piece 5a formed in the area (A) 14.

The height of the first protruding piece 5a is preferably 0.7 to 1.5 mm, and more preferably 0.7 to 1.2 mm. If the height of the first protruding piece 5a is more than the lower limit, high cleaning power is likely to be obtained. If the height of the first protruding piece 5a is below the upper limit, it becomes easy to insert the brush portion 3 between teeth.

It is desirable that the heights of each first protruding piece 5a of the brush portion 3 are all the same, but the height may become non-uniform due to manufacturing circumstances. This level of unevenness is acceptable as long as it is less than ±0.05mm and is considered to be the same height.

The height of each protruding piece (protruding pieces 5a to 5d) formed on the brush portion 3 is determined by measuring the height from the shaft member 4 when viewed in the extending direction (axial direction) of the shaft member 4 using a microscope or magnifying glass. It is obtained by measurement.

The thickness of the first protruding piece 5a is preferably 0.1 to 0.2 mm, and more preferably 0.10 to 0.15 mm. If the thickness of the first protruding piece 5a is more than the lower limit, it can be easily formed by injection molding. If the thickness of the first protruding piece 5a is below the upper limit, it becomes easy to insert the brush portion 3 between teeth.

Although it is desirable that the thickness of each first protruding piece 5a of the brush portion 3 is the same, the thickness may become non-uniform due to manufacturing circumstances. This degree of non-uniformity is acceptable as long as it is ±0.05mm or less.

The thickness of each protruding piece (protruding pieces 5a to 5d) formed in the brush portion 3 is measured using a microscope or magnifying glass, and when viewed in the direction of extension (center line direction) of each protruding piece, it includes a cross section perpendicular to that direction. It is obtained by measuring the diameter of the smallest circle.

<Second Projection>

The second protruding piece 5b is a plate-shaped member for scraping off tartar, etc. existing between teeth, and its height from the shaft member 4 is at least 0.1 mm lower than the height of the first protruding piece 5a.

It is desirable that the heights of the individual second protruding pieces 5b of the brush portion 3 are all the same, but the heights may become non-uniform due to manufacturing circumstances. This level of unevenness is acceptable as long as it is less than ±0.05mm and is considered to be of the same height.

The form in which the second protruding piece 5b is installed on the shaft member 4 is the same as that of the first protruding piece 5a, and the preferred form is also the same. The number of the second protruding pieces 5b protruding radially when viewed from the extension direction of the shaft member 4 is the number of the first protruding pieces 5a protruding radially when viewed from the extending direction of the shaft member 4 It's okay to be the same, or it's okay to be different.

The shape of the second protruding piece 5b in this example when viewed from the front is the same as the first protruding piece 5a except that the height from the shaft member 4 is at least 0.1 mm lower than that of the first protruding piece 5a. , the corners on both sides of the rectangular tip are rounded.

The shape of the second protruding piece 5b when viewed from the front may be a trapezoidal shape, a square shape, a rectangular shape, or a substantially elliptical shape whose width narrows toward the tip.

The height of the second protruding piece 5b is preferably 0.3 to 0.7 mm, and more preferably 0.3 to 0.5 mm, within a range of 0.1 mm or more lower than the height of the first protruding piece 5a. If the height of the second protruding piece 5b is more than the lower limit, high cleaning power is likely to be obtained. If the height of the second protruding piece 5b is below the upper limit, it becomes easy to insert the brush portion 3 between teeth.

The thickness of the second protruding piece 5b is preferably 0.1 to 0.2 mm, and more preferably 0.10 to 0.15 mm. If the thickness of the second protruding piece 5b is equal to or greater than the lower limit, it can be easily formed by injection molding. If the thickness of the second protruding piece 5b is below the upper limit, it becomes easy to insert the brush portion 3 between teeth.

<Area (A1)>

In the area A1 (12), the first protruding pieces 5a and the second protruding pieces 5b, which are lower in height than the first protruding pieces 5a, are alternately arranged in the axial direction, so that when inserted between teeth, Even if the first protruding piece 5a falls, the overlap between the first protruding pieces 5a becomes small because its neighbor is the second protruding piece 5b with a low height. Accordingly, the outer periphery of the brush portion 3 including the first protruding piece 5a when the first protruding piece 5a is collapsed in the area A1 (12) when viewed from the extending direction of the shaft member 4. The thickness of becomes thinner compared to the case where only the first protruding pieces 5a are arranged at equal intervals. Therefore, since the area A1 12 is formed, it becomes easy to insert the brush portion 3 between teeth.

In this way, the area A1 (12) has sufficient cleaning power due to the first protruding piece 5a, and the interdental insertion property is improved.

In the example area (A1) (12) of FIG. 6, the arrangement of the first protruding piece 5a and the second protruding piece 5b is such that the first protruding piece 5a and the second protruding piece 5b are oriented in the axial direction. If arranged alternately, the method of arranging the shaft members 4 around the axis is not particularly limited. That is, if the first protruding pieces 5a and the second protruding pieces 5b are alternated in the axial direction, all of the protruding pieces arranged around the axis of the shaft member 4 are the first protruding pieces 5a or the second protruding pieces 5b. It may be composed of two protruding pieces 5b, or the first protruding pieces 5a and the second protruding pieces 5b may be mixed.

3 and 6, a set in which four first protruding pieces 5a protrude in the X-axis direction and the Y-axis direction around the axis of the shaft member 4, and the and a set of four second protruding pieces 5b protruding in the y-axis direction are arranged alternately in the axial direction. In addition to this form, for example, a set in which two first protruding pieces 5a protrude in the X-axis direction around the axis of the shaft member 4 and two second protruding pieces 5b protrude in the Y-axis direction. and a set in which two second protruding pieces 5b protrude in the It may be arranged in a form.

The state in which two protruding pieces are arranged alternately in the axial direction refers to a state in which the front protruding piece appears to overlap at least a portion of the protruding piece on the depth side when viewed in the axial direction.

The axial distance between the adjacent first protruding piece 5a and the second protruding piece 5b in the area A1 (12) is preferably 0.3 to 0.8 mm, and the height of the second protruding piece 5b is preferably 0.3 to 0.8 mm. It is more preferable that the length is the same as . If the distance is more than the lower limit, the overlap between the first protruding piece 5a and the second protruding piece 5b is relatively relaxed, and interdental insertion is easy to increase. If the distance is below the upper limit, it becomes easy to hold plaque between the first protruding piece 5a and the second protruding piece 5b, and high cleaning power is easily obtained.

The total number of the first protruding pieces 5a and the second protruding pieces 5b arranged in the axial direction in the area A1 (12) is 16 in the example of FIG. 6. The total number is preferably 4 to 30, and more preferably 10 to 20. If the total number of the first protruding pieces 5a and the second protruding pieces 5b is within the above range, the function of both insertability and cleaning power of the area A1 (12) is likely to be sufficiently exerted.

<Area (A2)>

In the area A2 (13), since only the first protruding pieces 5a are arranged in the axial direction, the force for scraping off tartar and the like is strong, and high cleaning power is obtained.

The axial distance between the adjacent first protruding pieces 5a in the area A2 13 is preferably 0.3 to 1.5 mm, and more preferably 0.5 to 0.8 mm. If the distance is more than the lower limit, the overlap between the first protruding pieces 5a is relatively relaxed, and interdental insertion is easy to increase. If the distance is below the upper limit, it becomes easy to hold plaque between the first protruding pieces 5a, and high cleaning power is easy to be obtained.

The number of first protruding pieces 5a arranged in the axial direction in area A2 (13) is eight in this example.

In the area A2 (13), the number of first protruding pieces 5a arranged in the axial direction is preferably 3 to 30, more preferably 5 to 20. If the number of the first protruding pieces 5a is within the above range, the high cleaning power of the area A2 13 is likely to be sufficiently exerted.

In the present invention, in the area A, it is preferable that the axial distance between the protruding pieces of the arbitrary height (for example, 0.5 to 2.0 mm) increases toward the tip. This makes it easier for the tip side of area A to be inserted between teeth.

For example, in the example of FIG. 6, the axial distance between the first protruding pieces 5a in the area A1 (12) is the same as the distance between the first protruding pieces 5a in the area A2 (13). It is increasing by more than 0.1mm than the axial distance of . Accordingly, even if the first protruding piece 5a collapses when the region A (14) of the brush portion 3 is inserted between the teeth, the region A1 (12) on the distal end side remains in the region (A2) (13). Compared to this, it is difficult for the first protruding piece 5a to overlap.

Therefore, when viewed from the direction in which the shaft member 4 extends, the thickness of the area (A1) (12) where the distance between the first protruding pieces (5a) is large is thinner than the area (A2) (13), making insertion between the teeth Sexuality improves.

[Area (B)]

Area (B) 17 is an area that not only has cleaning power but also contributes to improving insertion ability when inserting the brush portion 3 between teeth.

In the area B1 (15) on the tip side of the area (B) 17, only the third protruding piece 5c, whose height from the shaft member 4 is 0.1 mm or more lower than the first protruding piece 5a, is provided on the shaft. are arranged in a direction. In the area B2 (16) on the rear end side of the area (B) (17), only the fourth protruding piece 5d, whose height from the shaft member 4 is 0.1 mm or more lower than the first protruding piece 5a, is provided on the shaft. are arranged in a direction. That is, in the area (B) 17, only protruding pieces whose height is 0.1 mm or more lower than the first protruding piece 5a are arranged in the axial direction. Additionally, the height of the fourth protruding piece 5d in the area (B2) (16) from the shaft member (4) is equal to or less than the height of the second protruding piece (5b) in the area (A1) (12). The height of the third protruding piece 5c in the region B1 (15) from the shaft member 4 is lower than the height of the fourth protruding piece 5d in the region B2 (16) by 0.1 mm or more.

In this way, the area (B1) (15), area (B2) (16), area (A1) (12), and area (A2) (13) in the brush portion 3 are enlarged in stages as a whole.

When the area (B) (17) is composed of the area (B1) (15) and the area (B2) (16), the area between the area (B1) (15) and the area (B2) (16) in the axial direction of the shaft material is The boundary is determined so that the area (B2) 16 is widest. Specifically, in this example, the area B1 (15) is an area from the third protruding piece 5c at the rearmost side to the third protruding piece 5c at the most distal end. The area B2 16 is an area from the fourth protruding piece 5d on the frontmost side to the fourth protruding piece 5d on the rearmost side.

<3rd protruding piece, 4th protruding piece>

The third protruding piece 5c and the fourth protruding piece 5d are plate-shaped members for scraping off tartar, etc. existing between teeth, and the height from the shaft member 4 is 0.1 higher than the height of the first protruding piece 5a. It is lower than mm. The height of the third protruding piece 5c from the shaft member 4 is 0.1 mm or more lower than the height of the fourth protruding piece 5d.

It is desirable that the heights of the individual third protruding pieces 5c of the brush portion 3 are all the same, but the heights may become non-uniform due to manufacturing circumstances. This level of unevenness is acceptable as long as it is less than ±0.05mm and is considered to be the same height.

It is desirable that the heights of the individual fourth protruding pieces 5d of the brush portion 3 are all the same, but the heights may become non-uniform due to manufacturing circumstances. This level of unevenness is acceptable as long as it is less than ±0.05mm and is considered to be of the same height.

The form in which the third protruding piece 5c and the fourth protruding piece 5d are installed on the shaft member 4 is the same as that of the first protruding piece 5a, and the preferred form is also the same. The number of third protruding pieces 5c protruding radially when viewed from the direction in which the shaft member 4 extends is equal to the number of fourth protruding pieces 5d protruding radially when viewed from the direction in which the shaft member 4 extends. It's okay to be the same, or it's okay to be different.

The shape of the third protruding piece 5c and the fourth protruding piece 5d in this example when viewed from the front is similar to that of the first protruding piece 5a except that the height from the shaft member 4 is at least 0.1 mm lower than that of the first protruding piece 5a. It is similar to the protruding piece 5a, and the corners on both sides of the rectangular tip are rounded.

The shape of the third protruding piece 5c and the fourth protruding piece 5d when viewed from the front may be a trapezoidal shape, a square shape, a rectangular shape, or a substantially oval shape with the width narrowing toward the tip.

The height of the third protruding piece 5c is preferably at least 0.1 mm lower than the height of the fourth protruding piece 5d, and is preferably 0.1 to 0.5 mm, and more preferably 0.1 to 0.3 mm. If the height of the third protruding piece 5c is more than the lower limit, the realistic feeling of cleaning by the protruding piece is likely to be obtained. If the height of the third protruding piece 5c is below the upper limit, the insertion property of the brush portion 3 between teeth becomes higher.

The thickness of the third protruding piece 5c may be the same as that of the first protruding piece 5a or the second protruding piece 5b, or may be thicker than them. However, the upper limit is preferably 1.5 mm. If the thickness of the third protruding piece 5c is below the upper limit, high cleaning power is likely to be obtained.

The height of the fourth protruding piece 5d is preferably 0.3 to 0.7 mm in the range of 0.1 mm or more lower than the height of the first protruding piece 5a and 0.1 mm or more higher than the height of the third protruding piece 5c, and is preferably 0.3 mm or more. ~0.5 mm is more preferred. If the height of the second protruding piece 5b is more than the lower limit, high cleaning power is likely to be obtained. If the height of the second protruding piece 5b is below the upper limit, it becomes easy to insert the brush portion 3 between teeth.

The thickness of the second protruding piece 5b is preferably 0.1 to 0.2 mm, and more preferably 0.10 to 0.15 mm. If the thickness of the second protruding piece 5b is equal to or greater than the lower limit, it can be easily formed by injection molding. If the thickness of the second protruding piece 5b is below the upper limit, it becomes easy to insert the brush portion 3 between teeth.

<Area (B1), Area (B2)>

Since the area (B) 17 includes only protruding pieces that are 0.1 mm or more lower than the first protruding piece (5a), when viewed from the extending direction of the shaft member (4), the area (B) ( 17) becomes thinner. Therefore, area (B) 17 is easier to insert between teeth than area (A) 14. Since the region (B) 17 on the tip side of the brush portion 3 can be easily inserted between teeth, the region (A) 14 following it can also be easily inserted stably between teeth.

Additionally, in the area (B2) 16, only the fourth protruding piece 5d, which is 0.1 mm or more lower in height than the first protruding piece 5a in the area (A) 14, is arranged in the axial direction. Additionally, the height of the third protruding piece 5c arranged in the area B1 (15) is lower than the height of the fourth protruding piece 5d arranged in the area B2 (16) by more than 0.1 mm. Accordingly, since the tip of the brush portion 3 is thinner, compared to the form in which only the fourth protruding piece 5d is arranged throughout the region B 17, the area between the teeth in the region B 17 Insertion is becoming more and more possible.

The number of third protruding pieces 5c arranged in the axial direction in area B1 15 is three in the example of Fig. 6. The number of third protruding pieces 5c arranged in the axial direction in area B1 15 is preferably 1 to 15, more preferably 1 to 10. If the number of the third protruding pieces 5c is within the above range, the function of assisting the interdental insertion of the region B1 (15) is likely to be sufficiently exercised.

The number of fourth protruding pieces 5d arranged in the axial direction in area B2 16 is five in this example. In the area B2 16, the number of fourth protruding pieces 5d arranged in the axial direction is preferably 1 to 20, more preferably 3 to 10. If the number of the fourth protruding pieces 5d is within the above range, the function of increasing the interdental insertion of the region B2 (16) is likely to be sufficiently exercised.

From the viewpoint of increasing the interdental insertion ability and cleaning power of the interdental toothbrush 1, the following examples can be given as preferable lengths of each region of the brush portion 3.

The length from the tip of the brush portion 3 to the last protruding piece 5 at the rear end is preferably, for example, 10 to 20 mm.

The combined length of area (A) (14) and area (B) (17) is preferably 10 to 20 mm, and the length ratio expressed as area (A) (14) / area (B) (17) is 1/10. ~5/10 is preferred.

The length ratio expressed by area (A1) 12/area (A2) 13 in area (A) 14 is preferably 3/1 to 1/3.

The length ratio expressed by area (B1) 15/area (B2) 16 in area (B) 17 is preferably 1/1 to 1/3.

(manufacturing method)

As a manufacturing method for the interdental brush of the second aspect of the present invention, a known manufacturing method can be adopted except that the height relationship of the protruding pieces arranged in the axial direction is adjusted as described above. In the interdental brush 1, for example, the first protruding pieces 5a to the fourth protruding pieces 5d are formed with the above-described regions A1, A2, B1, and B2. One example is a method of performing injection molding using a mold.

(action effect)

In the interdental brush of the second form of the present invention described above, the region B is formed on the front end side of the brush portion, and the region A is formed on the rear end side, thereby providing high cleaning power and interdental insertion ability. It is compatible. Furthermore, since the interdental brush of the second type of the present invention is made of synthetic resin, it is less likely to feel pain when it touches the gums, etc., and has a good touch feeling compared to an interdental brush provided with a wire.

In addition, the interdental brush of the second form of the present invention is not limited to the interdental brush 1 described above. For example, the interdental brush of the second form of the present invention may be an interdental brush in which the region A is composed only of the region A1, or an interdental brush in which the region A is composed only of the region A2. Additionally, the interdental brush of the second form of the present invention may be an interdental brush in which the region B consists only of the region B1, or an interdental brush in which the region B consists only of the region B2.

When the area B is composed of the area B1 and the area B2, the protruding piece in the area B1 has a height equal to or less than the fourth protruding piece in the area B2, and the fourth protruding piece in the area B1 It is good if a third protruding piece with a lower height than the other piece is included. For example, the area B1 may include both the third and fourth protruding pieces. Specifically, the area B1 may be an area in which protruding pieces of the same height as the protruding pieces of the area B2 and protruding pieces of a lower height than the protruding pieces of the area B2 are alternately arranged in the axial direction.

Furthermore, as shown in FIG. 5, the interdental brush of the present invention may be an interdental brush in which the distal end 4c of the shaft member 4 is spherical. With the interdental brush, it is difficult to feel pain when the tip portion 4c of the shaft member 4 touches the gums, and the touch feeling is better. In this case, the spherical tip portion 4c is preferably formed of soft resin.

The configuration of the interdental brush of the second type described above can be applied as the configuration of the interdental brush of the first type described above.

Example

[Example 1]

The interdental brush 1 of the first embodiment was manufactured as follows.

Using a material that is a mixture of 85 parts by mass of polybutylene terephthalate (PBT) and 15 parts by mass of potassium titanate fiber (manufactured by Otsuka Chemical Co., Ltd., TISMO (registered trademark)), the core portion 4a and the shaft diameter portion of the shaft member 4 are formed. The gripping portion 2 including (2a) was integrally injection molded using a mold of a corresponding shape.

The length from the tip 4p to the base end 4q of the core portion 4a of the shaft member 4, whose diameter is reduced as it moves toward the tip, is 12.0 mm, and the thickness of 0.1 mm from the tip is ϕ0.32 mm (0.080 mm2), The thickness of 12.0 mm from the tip was ϕ0.92 mm (0.664 mm2).

Next, by injection molding using a mold, a polyester-based elastomer is coated to a thickness of 0.15 mm on part of the surface of the core portion 4a and the reduced diameter portion 2a, and the coating portion 4b and the soft resin layer 6 are formed. formed. At this time, a plurality of protruding pieces 5 were formed integrally with the covering portion 4b, and an interdental brush 1 was obtained.

The length of the brush portion 3 of the manufactured interdental brush 1 was 12.0 mm from the tip (tip 4c of the shaft member 4) to the proximal end 3a.

Table 1 shows the results of measurements of the bending elastic modulus and tensile elongation at break of the materials constituting the core portion 4a of the shaft member 4 of this example in accordance with ASTM D790 and ASTM D638, respectively.

Table 1 shows the results of measuring the strengths of (A) to (C) for the interdental brush (1) of this example using the test method described above.

The results shown in Table 1 are the average values of the results of measuring and testing five interdental brushes (1).

[Example 2]

An interdental brush was manufactured in the same manner as in Example 1, except that a mixed material of 80 parts by mass of PBT and 20 parts by mass of TISMO was used.

[Comparative Example 1]

An interdental brush was manufactured in the same manner as in Example 1, except that a mixed material of 70 parts by mass of PBT and 30 parts by mass of TISMO was used.

[Comparative Example 2]

An interdental brush was manufactured in the same manner as in Example 1, except that 100 parts by mass of PBT was used and a material not mixed with TISMO was used.

[Comparative Example 3]

An interdental brush was manufactured in the same manner as in Example 1, except that a mixture of 92.5 parts by mass of PBT and 7.5 parts by mass of glass fiber was used.

For the above examples and comparative examples, the results of each physical property measured in the same manner as Example 1 are shown in Table 1.

Details of the raw materials used in the production of each interdental brush are as follows.

The fiber length of TISMO is 10-20㎛ and the fiber diameter is 0.3-0.6㎛.

The fiber length of glass fiber is 200-300㎛ and the fiber diameter is 10-20㎛.

[Evaluation of durability]

For each interdental toothbrush manufactured in the above examples and comparative examples, 10 panelists used them for one week and evaluated their durability. In one week of use, if 6 or more panelists damaged the brush part of the interdental toothbrush, durability was evaluated as low (×), and if 6 or more panelists could continue to use it without damage, durability was evaluated as high (×). ○). The results are shown in Table 1.

From the results shown in Table 1, it is clear that the interdental brushes of Examples 1 and 2, which satisfy the strength standards of (A) to (C), have a bending modulus of 3.0 GPa or more, and have a tensile elongation at break of 7.0% or more, have excellent durability. do.

1: Interdental brush
2: Gripping part
2a: Reduced diameter (expanded diameter)
3: Brush section
3a: Base of brush part
4: Accumulation
4a: deep
4b: covering part
4c: tip
4p: tip of core
4q: The base of Simbu
5: Projection piece
5a: first protrusion piece
5b: second protruding piece
5c: Third protrusion piece
5d: Fourth protrusion
6: Soft resin layer coated on the neck shaft
10: Primary product (aircraft)
14: Area (A)
17: Area (B)
12: Area (A1)
13: Area (A2)
15: Area (B1)
16: Area (B2)

Claims (10)

An interdental brush having a grip portion and a brush portion installed at the tip of the grip portion,
The brush portion includes a shaft made of a core made of a first synthetic resin extending from the grip portion and a covering portion formed by covering the core with a second synthetic resin softer than the first synthetic resin, and a plurality of protruding pieces protruding from the shaft. Provided, the first synthetic resin includes a fibrous filler having a fiber length of 3 ㎛ to 300 ㎛ and a fiber diameter of 0.1 ㎛ to 2.0 ㎛,
The interdental brush satisfies the following (A) to (C).
(A) Axial bending strength; The repulsive force when a portion 5 mm from the tip of the shaft member is bounced at a speed of 10 mm/sec is 0.56 N or more.
(B) Axial bending strength; A left-right bending test in which the proximal end portion of the brush portion is bent 90 degrees in a first direction perpendicular to the axis of the shaft member, returned to its original state, and bent 90 degrees in a second direction opposite to the first direction and returned to its original state. In this case, the number of bending times in the same direction until the core portion is fractured is 20 or more.
(C) Cyclic bending strength; In a 90-degree bending test in which the proximal end portion of the brush portion is bent 90 degrees in a first direction perpendicular to the axis of the shaft member and returned to its original state, the maximum stress at the fifth bending in the same direction is 1.7 N. That's it. According to claim 1,
An interdental toothbrush in which the core component material has a bending modulus of 3.0 GPa or more as measured in accordance with ASTM D790 and a tensile elongation at break of 7.0% or more as measured in accordance with ASTM D638. delete According to claim 1,
The fibrous filler is an interdental brush containing potassium titanate fibers. The method of claim 1 or 2,
An interdental brush wherein the first synthetic resin includes polyester. An interdental brush made of synthetic resin having a grip portion and a brush portion provided at the tip of the grip portion,
The brush portion includes a shaft member extending from the tip of the grip portion, and a plurality of protruding pieces that protrude from the shaft member and are each independently arranged around the axis of the shaft member,
The protruding piece protrudes radially when viewed from the direction in which the shaft member extends,
The brush portion includes a region (A) formed near the rear end of the region (B) and a region (B) formed near the front end of the region (A),
When the distance from the shaft member to the tip of the radially protruding protruding piece is taken as the height, first protruding pieces of arbitrary height are arranged in the axial direction in the area A,
In the region B, only protruding pieces having a height lower than the first protruding piece are arranged in the axial direction, and in the region A, the first protruding piece and a second protruding piece having a lower height than the first protruding piece. An interdental brush whose teeth include regions (A1) arranged alternately in the axial direction. delete According to claim 6,
The region (B) includes a region (B1) at the front end and a region (B2) at the rear end of the region (B1),
In the area B2, only fourth protruding pieces with a height equal to or less than that of the second protruding pieces are arranged in the axial direction,
The protruding piece in the area (B1) has a height equal to or lower than the fourth protruding piece, and the area (B1) includes a third protruding piece that is lower in height than the fourth protruding piece. According to claim 6 or 8,
An interdental toothbrush in which, in the region A, the axial distance between the first protruding pieces increases toward the tip. According to claim 6 or 8,
An interdental toothbrush in which an enlarged diameter portion that expands from the front end toward the rear end is formed near the brush portion of the grip portion.

Images