JP6750329B2 - Interdental cleaning tool - Google Patents

Description

The present invention relates to an interdental cleaning tool.

Interdental cleaning tools are widely used to prevent tooth decay and periodontal disease, for example, by removing food residues sandwiched between the teeth and plaque that causes tartar that tends to adhere to the roots of teeth. Has been. As an interdental cleaning tool, for example, a base material part made of a synthetic resin and a soft part made of an elastomer are provided, and the base material part is a handle base material part which is a handle and a tip part of the handle base material part. It has an elongated shaft-shaped core base part that is continuously provided, and the soft part has a cleaning soft part that covers the tip side of the core base part, and the tip side of the core base part and the cleaning soft part. A resin interdental cleaning tool having a cleaning section has been put into practical use (see, for example, Patent Documents 1 to 3). Such an interdental cleaning tool is configured to remove plaque and food dregs by inserting the cleaning unit between the teeth and reduce inflammation of the gums by massaging the roots of the teeth in the cleaning unit. Has been done.

A conventional resin interdental cleaning tool uses, for example, a first mold having a plurality of first molding spaces and a second mold having a same number of second molding spaces as the first molding spaces. Supplying a synthetic resin to the first molding space to mold a primary molded product in which a plurality of base material parts are connected by a runner part, and charging the primary molded product to the second molding space to supply an elastomer, It is manufactured as a connected body of a plurality of interdental cleaning tools by a two-color molding method including a step of molding a soft part on the surface of the core base material part.

In the two-color molding method described in Patent Document 4, when the soft part is molded using the second mold, the elongated shaft-shaped core base material part is displaced from a predetermined position due to the injection pressure of the elastomer or the like, resulting in poor coverage of the elastomer. In order to prevent the defective molding of the first molded product from occurring, a pair of members, which are arranged to face each other in a direction substantially perpendicular to the primary molded product, are supported in a region where the soft part is to be formed in the second molding space so as to be close to and away from each other. It is disclosed that a second mold having a plurality of holding pins for positioning is used. According to the second mold, it is possible to prevent the molding failure from occurring by bringing the pair of holding pins into contact with the front and back surfaces of the tip end portion and the base end portion of the core base material portion.

Japanese Patent No. 4236571 Japanese Patent No. 30026868 Special table 2001-506514 gazette International Publication No. 2013/176297

When the cleaning unit is inserted between the teeth, a large compression force acts in the axial direction. In addition, when cleaning the molars, especially the molars, the front side of the anterior teeth, etc., it is necessary to insert and remove the cleaning unit between the teeth in a state of being curved at 60° to 90° from the tip to the middle, so cleaning A large bending load acts on the part. Therefore, even if the synthetic resin forming the base material has relatively high mechanical properties, the cleaning portion is likely to be bent or deformed without restorability.

When inserting the cleaning part between the teeth, it is necessary to bend the cleaning part, especially the tip part thereof. However, when the cleaning part needs to be largely curved, such as between the molars or on the back side of the lower anterior teeth, the position of the tip of the cleaning part can be controlled with the fingertips due to the rapid bending. It becomes difficult, and the interdental insertability of the cleaning part deteriorates. In addition, when the cleaning unit does not bend, an excessive load is applied to the cleaning unit during interdental insertion or interdental cleaning, so that the cleaning unit is likely to break.

The core base material made of super engineering plastic such as polyether sulfone is easily bent, and the cleaning portion can be prevented from being broken. However, since a very high injection temperature is indispensable for the molding of super engineering plastics, the cooling time after injection molding of the base material portion becomes long and the productivity of the interdental cleaning tool decreases. In addition, the material cost is high, the production equipment such as an injection molding machine is overheated, and deterioration is likely to occur, resulting in an increase in total manufacturing cost.

An object of the present invention is an interdental cleaning tool made of a resin material and an elastomer, which is excellent in insertability into the interdental space of the cleaning section, and which prevents the cleaning section from breaking during interdental cleaning. Is to provide.

As a result of intensive studies to solve the above-mentioned problems, the present inventors set the elastic modulus of the core base material portion within a predetermined range, so that the cleaning portion has appropriate flexibility and appropriate rigidity. Since the core base material part and the cleaning soft part made of elastomer are likely to undergo an integral structural change, the cleaning part during interdental cleaning can be performed while maintaining good interdental insertability of the cleaning part. The inventors have found that the bending resistance of the above can be remarkably improved, and have completed the present invention.

That is, the present invention provides the following interdental cleaning tool (1) to (11).

(1) A base member made of a resin material containing a synthetic resin, which has a handle base member serving as a handle and an elongated shaft-shaped base member continuous with a front end of the handle base member; An interdental cleaning tool including a cleaning soft part having a coating part that covers at least a part of the base part, and a soft part made of an elastomer, wherein the core base part is covered with the cleaning soft part. And a second shaft portion, one end of which is substantially coaxially connected to the first shaft portion and the other end of which is continuously connected to the distal end side of the handle base material portion. The portion has a proximal end diameter of d ₁ (mm), the proximal end of the first shaft portion is a fixed end and the distal end is a free end, and the interdental cleaning tool is held horizontally, In the measurement in which the load (P) is vertically downwardly applied at the position of L (mm) toward the tip side of the first shaft portion with the boundary position between the first shaft portion and the second shaft portion as the starting point, the first shaft portion is The bending amount when the maximum load value in the load region where elastic deformation is maintained is applied as the load (P) is Y _max (mm), and the diameter of the first shaft portion at the position where the load (P) is applied is d ₂ (Mm), the interdental cleaning tool is characterized in that the elastic modulus E of the core base material portion calculated from the following formula (1) is 3000 MPa or more.
E=[64P/(Y _max ·π)]·(m+n) (1)
Wherein ^{(1), m = - [} 3 · (D) 3 · (d 1 + D · L)] ^-1.
n ⁼ a ^{_{[D 2 · L 2 -d 1}} · L · D + (d 1) 2] / [3 · (d 1) 3 · (D) 3]. In the above formulas, D=(d ₂ −d ₁ )/L. ]

The core base material part provided in the interdental cleaning tool of the present invention is covered with the cleaning soft part, and the first shaft part is the tip side shaft part that constitutes the cleaning part together with the cleaning soft part, and one end is the first shaft. And a second shaft part which is connected to the handle base part at the other end and is exposed without being covered by the cleaning soft part. The first and second shaft portions are connected substantially coaxially. The proximal end diameter d ₁ (mm) of the first shaft portion is the diameter of the first shaft portion at the boundary between the first and second shaft portions.

In the interdental cleaning tool according to (1) above, with the interdental cleaning tool held in the horizontal direction, the proximal end of the first shaft portion of the core substrate is a fixed end and the distal end is a free end. , A position of L (mm) toward the tip (or end) side of the first shaft portion starting from the boundary position between the first shaft portion and the second shaft portion (the diameter of the first shaft portion at this position is d ₂ ( mm)) in the vertical direction downward to obtain the load displacement curve, the maximum load value in the load region in which the first shaft portion maintains elastic deformation is the load (P). When the amount of flexure when loaded as is Y _max (mm), the elastic modulus E of the core base material portion obtained from the equation (1) is 3000 MPa or more. Here, holding the interdental cleaning tool in the horizontal direction means holding the interdental cleaning tool such that the axis of the core base material portion and the horizontal direction substantially coincide with each other.

When the elastic modulus E of the core base material portion obtained from the equation (1) is set within the predetermined range as in the present invention, the elastomer constituting the soft coating portion has almost no influence on the maximum deflection amount Y _max . Therefore, when the load P(N) is applied to the position on the cleaning portion having the length L (mm) toward the tip side, the boundary position between the first shaft portion and the second shaft portion is the starting point. , A substantially corresponding value is obtained by applying the bending amount Z _max at the end of the linear region where the cleaning portion can maintain elastic deformation in the load displacement curve of the cleaning portion instead of Y _max in the equation (1). It has been proved by the study of the present inventors.

According to the interdental cleaning tool of the above (1), by setting the elastic modulus E of the core base material portion calculated from the equation (1) to 3000 MPa or more, the first shaft portion of the core base material portion and the cleaning soft portion are obtained. The rigidity of the cleaning section as a whole does not increase, but the cleaning section as a whole has both appropriate flexibility and appropriate rigidity, which contributes to improved interdental insertion of the cleaning section. Since the flexibility and the rigidity cooperate to prevent the cleaning portion from being broken during the interdental cleaning, the interdental insertability is further improved, and at the time of interdental cleaning, especially the molars and the mandibular anterior teeth. Even at the time of cleaning between teeth such as the back side where the cleaning section needs to be largely curved, the cleaning section can be prevented from being significantly broken.

(2) The interdental cleaning tool according to (1) above, wherein the soft cleaning portion further includes a plurality of protrusions that are integrated with the covering portion and project outwardly at intervals in the longitudinal direction of the covering portion. ..
In the interdental cleaning tool of the above (2), the soft part for cleaning together with the covering portion includes a plurality of protrusions integrally formed with the covering portion so as to project outwardly at intervals in the longitudinal direction of the covering portion. It is a form. Even in such a form, by setting the elastic modulus E of the core base member to be 3000 MPa or more, the same effect as that of the interdental cleaning tool (1) can be obtained.

(3) The interdental cleaning tool according to (1) or (2) above, wherein the length L is preferably 3 mm to 12 mm (more preferably 5 mm to 10 mm).
According to the interdental cleaning tool of the above (3), by setting the length L to be in the range of 3 mm to 12 mm (more preferably 5 mm to 10 mm, further preferably 10 mm), the elastic modulus E of the core base material portion can be further improved. It becomes possible to accurately measure and calculate, and if the elastic modulus E is obtained, the performance such as the bending resistance of the interdental cleaning tool can be known almost accurately.

(4) The interdental cleaning tool according to any one of (1) to (3) above, wherein the core substrate has an elastic modulus E of 3000 MPa or more and 7200 MPa or less.
According to the interdental cleaning tool of the above (4), by setting the elastic modulus E of the core base material portion obtained from the equation (1) to be in the range of 3000 to 7200 MPa, the cleaning portion has high flexibility and rigidity. Not only can the interdental insertability and fold resistance of the cleaning part be improved during interdental cleaning, but also irregular deformation of the cleaning part during interdental cleaning is less likely to occur. It is possible to prevent the pain caused by abrupt contact with or to hurt the inside of the oral cavity, and it is possible to use with confidence.

When the elastic modulus E of the core base material is less than 3000 MPa, the rigidity of the cleaning unit as a whole decreases too much, the interdental insertability of the cleaning unit decreases, and cleaning is performed during interdental insertion and interdental cleaning. There is a risk of sudden deformation of the parts. Further, when the elastic modulus E of the core base material exceeds 7200 MPa, the flexibility of the first shaft portion of the core base material may be insufficient, so that the cleaning portion is sufficiently bent during interdental cleaning. May not be prevented.

(5) The core base material portion has two or more core base material portion recesses at predetermined positions on the surface thereof, and the coating portion has a first side portion and a second side portion, and first and second sides. The section has two or more first and second coating section recesses which are arranged at predetermined intervals in the axial direction of the core base material section and which penetrate the coating section and are connected to the core base material section recess. An interdental cleaning tool according to any one of 1) to (4).

The interdental cleaning tool of the present invention includes, for example, a step of injecting a resin material into a first mold to mold a base material portion, and a step of inserting the base material portion into a second mold and injecting an elastomer to form a core substrate. It is produced by a two-color molding method including a step of covering the surface of the material portion and forming a soft portion for cleaning. Then, when covering the elastomer, in order to prevent the occurrence of defective molding due to movement of the core base member, a pair of holding pins are abutted from a plurality of axial positions of the core base member, for example, from the vertical direction. Fix it. In such a two-color molding method, a plurality of through holes derived from the holding pins are formed in the soft portion (covering portion) for cleaning after molding at intervals in the axial direction, and are connected to the through holes. A core base material recess having a minute depth is formed on the exposed surface of the core base material. In the present specification, a recess including a through hole (first or second coating recess) of the soft cleaning portion (cover) and a core base recess connected to the through hole may be referred to as a “cleaning recess”.

Further, the first and second side portions of the covering portion are, in the second die for forming the cleaning soft portion, one side half portion of the cleaning soft portion outer peripheral surface formed by one die, and the other side. It means the remaining one-side half of the outer peripheral surface of the soft part for cleaning formed by a mold.

The interdental cleaning tool according to (5) above is an embodiment in which the coating portion of the soft cleaning portion has first and second coating portion recesses on its first and second side portions, respectively. As described above, the interdental cleaning tool is a soft part molding in which a plurality of softening parts (coating parts) for cleaning are formed on the surface of the core base part by fixing a plurality of positions of the core base part with a pair of holding pins. It is obtained by a method for manufacturing an interdental cleaning tool including steps. The first and second coating recesses may cause a large concentration of stress during interdental cleaning and may cause breakage of the cleaning portion. However, the elastic modulus E of the core base material is set within the above predetermined range. As a result, it is possible to reduce the concentration of stress in the recesses of the first and second covering portions and their surroundings, and prevent the cleaning portion from being broken during the interdental cleaning, while maintaining good interdental insertability of the cleaning portion. it can.

(6) The interdental cleaning tool according to (5), in which two or more first coating portion recesses and two or more second coating portion recesses are arranged in a face-to-face manner with the core base material portion interposed therebetween. ..
The interdental cleaning tool according to (6) above is an embodiment in which first and second recesses of the covering portion are provided at positions facing the covering portion of the soft portion for cleaning with the core base material portion therebetween. Also in such an embodiment, by setting the elastic modulus E of the core base material portion within the above-mentioned predetermined range, concentration of stress in the first and second coating portion recesses and the periphery thereof is relaxed, and the cleaning portion is excellent. It is possible to prevent breakage of the cleaning portion during interdental cleaning while maintaining interdental insertability.

(7) At least one of the first and second coating portion concave portions is long in the axial direction of the cleaning portion (elliptical shape, oval shape, rectangular shape, oval shape, oval type/bale type (short side is curved) The interdental cleaning tool according to the above (5) or (6), which has a rectangular shape, a rounded rectangular shape, a teardrop shape, a parallelogram shape, or the like that is long in the spiral direction of the cleaning unit axis.
The interdental cleaning tool according to (7) above is an embodiment in which at least one of the first and second recessed portions is a recess that is long in the axial direction of the core base material portion. The axially long coating recessed portion of the core base material has a function of relieving the concentration of large stress on the periphery during interdental cleaning, and the core base material portion has a pressure of 3000 MPa or more (preferably 3000 to 7200 MPa). In the method for manufacturing an interdental cleaning tool including the step of forming the soft cleaning portion by using the holding pin, since it has the elastic modulus E obtained from the equation (1), the interdental insertability and interdental property of the cleaning portion It is possible to obtain an interdental cleaning tool with significantly improved breakage resistance during cleaning. In addition, in order to form the covering portion concave portion that is long in the axial direction of the core base material portion, for example, the sectional shape of the holding pin may be appropriately selected.

(8) The tooth of any one of (1) to (7), wherein the first shaft portion has d ₁ >d ₂ and has a tapered shape in which the diameter gradually decreases from the base end side toward the tip end side. Inter-cleaning tools.
According to the interdental cleaning tool of the above (8), the interdental insertability and the handleability during interdental cleaning can be further improved while maintaining good bending resistance of the cleaning portion during interdental cleaning. ..

(9) The interdental space according to any one of (1) to (8) above, wherein the resin material includes a synthetic resin and at least one kind of filler selected from the group consisting of fibrous fillers and plate-like fillers. Cleaning tool.
According to the interdental cleaning tool of the above (9) using the fibrous filler, the rigidity of the core base material in the axial direction can be further enhanced, and the interdental insertability can be further improved, and the core base material part can be further improved. Since the bending of the cleaning portion due to the stiffening of the core is alleviated by setting the elastic modulus E of the core base material portion calculated from the formula (1) to 3000 MPa or more (preferably 3000 to 7200 MPa), it is relatively good. Bending resistance can be maintained. Further, according to the interdental cleaning tool of (9) using the plate-shaped filler, the rigidity of the core base material in the axial direction can be further enhanced, and the interdental insertability can be further improved. Interdental cleaning by the synergistic effect of the flexibility imparted to the entire core base material portion by the filler and the elastic modulus E of the core base material portion of 3000 MPa or more (preferably 3000 to 7200 MPa) obtained from the formula (1). Since it is possible to impart flexibility to the cleaning portion to withstand a large bending load at the time, it is possible to obtain an interdental cleaning tool having excellent interdental insertability of the cleaning portion and bending resistance during interdental cleaning.

(10) The interdental cleaning tool according to (9) above, wherein the filler is a plate-like filler or a mixture of a plate-like filler and a fibrous filler.
According to the interdental cleaning tool of the above (10), the breakage resistance during interdental cleaning can be further improved.

(11) The interdental cleaning tool according to any one of (1) to (10) above, wherein the synthetic resin is a thermoplastic resin having a melting point of 150° C. or higher.
According to the interdental cleaning tool of the above (11), the productivity of the interdental cleaning tool can be improved by shortening the molding time of the base material part, particularly the cooling time after molding, thereby improving the productivity, and by extension, the teeth. The manufacturing cost of the inter-cleaning tool can be reduced. From the viewpoint of further enhancing the effect, among the thermoplastic resins having a melting point of 150° C. or higher, a thermoplastic resin in which at least a part is crystalline is more preferable.

According to the present invention, it is possible to provide an interdental cleaning tool that has good interdental insertability and that effectively prevents breakage of the cleaning portion during interdental cleaning.

It is a front view which shows typically the structure of the interdental cleaning tool coupling body. It is a schematic diagram which shows the structure of the principal part of the interdental cleaning tool coupling body shown in FIG. 1, (a) is a front view, (b) is a side view. It is a front view which expands and shows the connection part vicinity of the interdental cleaning tool connection body. It is sectional drawing in the IV-IV cutting plane line shown in FIG. It is a schematic diagram which expands and shows the cleaning part with which the interdental cleaning tool of 1st Embodiment is equipped, (a) is a front view, (b) is a side view. FIG. 6 is a cross-sectional view taken along the line VI-VI shown in FIG. It is a front view which expands and shows the structure of the cleaning part of 2nd Embodiment typically. It is sectional drawing of the cleaning part shown in FIG. It is a front view which expands and shows the structure of the cleaning part of 3rd Embodiment typically. It is a graph which shows the load displacement curve obtained by the load application test of the 1st axis part using a precision universal testing machine. The horizontal axis represents displacement and the vertical axis represents load.

The interdental cleaning tool of the present invention includes a base material part made of a resin material and a soft part made of an elastomer. The base material portion includes a handle base material portion that serves as a handle, and an elongated shaft-shaped core base material portion that is continuously provided on the distal end side of the handle base material portion. The soft part includes a cleaning soft part having a covering part that covers at least a part of the core base part, and the cleaning soft part is formed with the covering part so as to project outward with a gap in the longitudinal direction of the covering part. In addition, it may have a plurality of protrusions formed integrally with the covering portion. In the interdental cleaning tool of the present invention, functionally, the handle base material portion constitutes a handle portion, and the core base material portion and the cleaning soft portion constitute a cleaning portion.

In the interdental cleaning tool of the present invention, the core base material portion includes a second shaft portion that is connected to the tip end side of the handle base material portion and a first shaft portion that is substantially coaxially connected to the tip end side of the second shaft portion. The proximal end side of the first shaft portion (the side connected to the second shaft portion) has a terminal diameter of d ₁ (mm).

In the interdental cleaning tool of the present invention, the core substrate has an elastic modulus E of 3000 MPa or more, preferably 3000 MPa or more and 7200 MPa or less, more preferably 3000 MPa or more and 6500 MPa or less, further preferably 3500 MPa or more and 6000 MPa or less, particularly preferably It is characterized by being 4000 MPa or more and 6000 MPa or less. By setting the elastic modulus E of the core base material portion to 3000 MPa or more, the interdental cleaning is performed while maintaining good interdental insertability and handleability of the cleaning section including the first shaft section and the soft cleaning section. It is possible to significantly prevent the cleaning portion from being broken at that time.

The elastic modulus E of the core base material can be obtained from the equation (1). The method of deriving the equation (1) will be described later.
E=[64P/(Y _max ·π)]·(m+n) (1)
[In the formula (1),
m=-[3·(D) ³ ·(d ₁ +D·L)] ⁻¹ (a)
^{_{n = [D 2 · L 2}} -d 1 · L · D + (d 1) 2] / [3 · (d 1) 3 · (D) 3] ... (b)
Is. Wherein (a) and Formula (b), is _{D = (d 2 -d 1)} / L. ]

Hereinafter, “L”, “d ₁ ”, and “d ₂ ”in the formulas (a) and (b), and “Y _max ”in the formula (1) will be described in order.

In order to obtain the elastic modulus E of the core base material portion, first, it is necessary to obtain a load displacement curve of the core base material portion by measurement, and to obtain Y _max from this load displacement curve. The measurement is carried out by holding the interdental cleaning tool in a horizontal direction, and then, in the first and second shaft portions constituting the core base material portion, the proximal end of the first shaft portion is fixed to the fixed end and the distal end. With a free end, a load (P) is applied vertically downward at a position of L (mm) on the tip side of the first shaft portion with the boundary position between the first and second shaft portions as a starting point, and the load (P) is aged over time. The load displacement curve is obtained as a measurement result. This measurement corresponds to a compression test or a cantilever bending test, and was performed using a precision universal tester (manufactured by Shimadzu Corporation) as a measuring device (compression tester).

In the compression tester, a resin plate (an epoxy resin plate in the above measurement) having a flat surface without unevenness is placed on a sample table on which a sample is placed, and the base portion of the interdental cleaning tool is placed on the resin plate. To place. On top of that, place a stainless jig for fixing the sample with the flat surface facing down, and apply the minimum force so that the core base material part does not compressively deform and the base material part does not move. Fix the sample with a tool (for example, fix it with a screw so that the sample is not deformed). Here, the length of the second shaft portion was set to 20 mm. Then, a jig for bending with respect to a predetermined position (L (mm) position from the boundary position of the first and second shaft parts as a starting point) of the first shaft part protruding from the gap between the resin plate and the stainless steel jig. The load displacement curve can be obtained by recording the displacement of the first shaft portion while abutting the first shaft portion from above and lowering it at a predetermined speed (for example, 30 mm/min) to increase the load of the load. To be

Here, the boundary position between the first and second shaft portions also corresponds to the proximal end of the first shaft portion, and the diameter thereof is d ₁ (mm). Further, the diameter of the first shaft portion at the position of L (mm) from the boundary position of the first and second shaft portions to the tip side of the first shaft portion is d ₂ (mm). As the diameter d ₁ and the diameter d ₂ , measured values by calipers are used. L (mm) is a load application position on the first shaft portion starting from the boundary position between the first and second shaft portions.

The length L (mm) indicating the load position is not particularly limited and can be appropriately selected from the range of the length of the first shaft portion, but the accuracy, reproducibility, and elastic modulus of the obtained elastic modulus E can be selected. Considering the relationship between E and properties such as bending resistance, the thickness is preferably 3 to 12 mm, more preferably 4 to 11 mm, further preferably 5 to 10 mm, and particularly preferably 10 mm. A load P(N) is applied at a position in such a numerical range to obtain an elastic modulus E, and when the elastic modulus E is within the above-mentioned predetermined range, a tooth having high bending resistance while maintaining interdental insertability. It becomes a cleaning tool.

In the first shaft part, the substantial length (mm) of the first shaft part, which is the length from the end of the base end part (the position of the diameter d ₁ ) to the load load position (the position of the diameter d ₂ ) is Depending on the product design of the interdental cleaning tool, it may be longer than 10 mm or may be 10 mm or less. When it is longer than 10 mm, the load P(N) can be applied to the position of L=10 mm, and when it is 10 mm or less, an appropriate value of L that allows load application is selected from the above range of L. Therefore, the load P(N) can be applied.

Next, a method for obtaining Y _max will be described with reference to FIG. FIG. 10 is a graph showing a load displacement curve of the first shaft portion. In the load-displacement curve of the precision universal testing machine, as the load increases, an irregular region where the relationship between load and displacement becomes random appears at the beginning of measurement, and this elastic region follows the irregular region. Appears, and further passes through the plastic deformation region, leading to rupture (rapid decrease in load). In FIG. 10, the illustration of the irregular region is omitted, and the elastic deformation region and subsequent regions are shown. In the load displacement curve shown in FIG. 10, the elastic deformation region is a linear region, and the plastic deformation region is a curved region continuing from the end of the linear region. In the present invention, the load (P) at the end of the linear region is the maximum load (value) in the load region where the first shaft portion maintains elastic deformation, and the displacement (mm) at the end is Y _max . When the material of the first shaft portion, the diameters d ₁ and d _2, etc. are changed, a load displacement curve including a linear region and a subsequent curved region is obtained although the load value and the displacement amount are changed. Since the points are common, Y _max can be easily obtained.

By substituting L, d ₁ , d ₂ and Y _max obtained as described above into the equation (1), the elastic modulus of the first shaft portion can be obtained. In the present invention, the elastic modulus of the first shaft portion thus obtained is the elastic modulus of the core base material portion. In the above formula (1), since there are only three types of variables involved in the design of the interdental cleaning tool, L, d ₁ and d ₂ , based on the selection of the resin material and the elastomer, the three types of By appropriately selecting the variables, it is possible to suitably obtain the interdental cleaning tool having excellent interdental insertability and bending resistance.

Next, a method of deriving the formula (1) will be described. The equation (1) is derived from the differential equation of the deflection curve represented by the following equation (2). The differential equation represents an elastic curve after the beam member (here, the cleaning unit) is deformed by receiving a load.
d ² y/dx ² =−M(x)·[E·I(x)] ⁻¹ (2)
[In the formula (2), E is elastic modulus, I(x) is elastic second moment, E·I(x) is bending rigidity, and M(x) is moment. ]

A proximal end diameter d ₁ (mm), a diameter d ₂ (mm) of the first shaft portion at a load position, and a first shaft portion having a length L (mm) (preferably interdental insertion of the cleaning portion). From the viewpoint of the sex and the like, consider a model in which d ₁ >d ₂ ) is fixed to the base end and held in the horizontal direction, and the tip end is a free end. When a load P (MPa) is vertically applied to the cleaning unit at a position t (mm) from the load applying unit (that is, a position x (mm) from the end on the proximal end side, t+x=L), The bending amount (displacement amount) of the first shaft portion is y (mm). The deflection amount y is the distance between the load bearing portion of the first shaft portion after the load P is loaded and the axis of the first shaft portion in the horizontal state before the load P is loaded. At this time, the elastic second moment I(x) is expressed by the equation (3), and the moment M(x) is expressed by the equation (4).
I(x)=(π/64)·[d ₁ +(d ₂ −d ₁ )·x/L] ⁴ (3)
M(x)=-Pt=-P(L-x) (4)

From equations (2) to (4),
d ² y/dx ² =
[64P(L−x)]·{Eπ·[d ₁ +(d ₂ −d ₁ )·x/L] ⁴ } ⁻¹ =
(64P/Eπ)·{(L−x)/[d ₁ +(d ₂ −d ₁ )·x/L] ⁴ }
Here, when D=(d ₂ −d ₁ )/L, the equation (5) is obtained.
d ² y/dx ² =(64P/Eπ)·[(L−x)/(d ₁ +D·x)] ⁴ (5)

Next, the expression in expression (5); [(L−x)/(d ₁ +D·x)] ⁴ is developed.
[(L−x)/(d ₁ +D·x)] ⁴ =
α/(d ₁ +D·x) ⁴ +β/(d ₁ +D·x) ³ +γ/(d ₁ +D·x) ² +δ/(d ₁ +D·x)=
[Α+β·(d ₁ +D·x)+γ·(d ₁ +D·x) ² +δ·(d ₁ +D·x) ³ ]/(d ₁ +D·x) ⁴

Here, α+β·d ₁ +γ·(d ₁ ) ² +δ(d ₁ ) ³ =L, the sum of variables for x: β·D+2γ·d ₁ ·D+3δ·(d ₁ ) ² ·D=−1, x The sum of variables for ^{2 is} γ·D ² +3δ·d ₁ ·(D) ² =0, and the sum of variables for x ^{3 is} δ·(D) ³ =0. Further, since (D) ² ≠0 and (D) ³ ≠0 and γ=δ=0, α=L+(d ₁ /D) and β=−D ⁻¹ . Substituting this into equation (5), d ² y/dx ² =(64P/Eπ)·{[(D·L+d ₁ )/D(d ₁ +D·x) ⁴ ]−[D(d ₁ +D· x) ³ ] ⁻¹ }. Therefore, the equation (6) is derived.
(Eπ/64P)·(d ² y/dx ² )=[(D·L+d ₁ )/D·(d ₁ +D·x) ⁴ ]−[D·(d ₁ +D·x) ³ ] ⁻¹ ... (6)

Next, the formula (7) is derived by integrating the formula (6), and the formula (8) is derived by integrating the formula (7) again.
(Eπ/64P)・(dy/dx)=
(D·L+d ₁ )/[−3(D) ² ·(d ₁ +D·x) ³ ]−[−2(D) ² ·(d ₁ +D·x) ² ] ⁻¹ +C1 (7)
(Eπ/64P)・y=
(D·L+d ₁ )/[6(D) ³ ·(d ₁ +D·x) ² ]-[2(D) ³ ·(d ₁ +D·x)] ⁻¹ +C 1 ·x+C 2 (8)
[In Formulas (7) and (8), C1 and C2 represent integration constants, respectively. ]

In the equations (7) and (8), when x=0, y=0 and the deflection angle θ (=dy/dx)=0. Therefore, the integration constants C1 and C2 are obtained. First, the following relational expression is derived by substituting x=θ=0 into the expression (7).
^{_{0 = [(D · L +}} d 1) / - 3 (D) 2 (d 1) 3] - [- 2 (D) 2 · (d 1) 2] -1 + C1
The integration constant C1 obtained from this relational expression is represented by the following expression (9).
C1=(2D·L−d ₁ )/[6(d ₁ ) ³ ·(D) ² ]... (9)
Further, the following relational expression is derived by substituting x=y=0 into the expression (8).
^{_{0 = (D · L + d}} 1) / [6 (D) 3 · (d 1) 2] - [2 (D) 3 · d 1] -1 + C2
The integration constant C2 obtained from this relational expression is represented by the following expression (10).
C2=(2d ₁ −D·L)/[6(d ₁ ) ² ·(D) ³ ]

By substituting the equations (9) and (10) into the equation (8), the following equation (11) is obtained.
y=(64P/Eπ)·{(D·L+d ₁ )/[6(D) ³ (d ₁ +D·L) ² ]}−[2(D) ³ ·(d ₁ +D·x)] ⁻¹ +{[(2D·L−d ₁ )·x]/[6d ₁ ·(D) ² ]}+{(2d ₁ +D·L)/[6(d ₁ ) ² (D) ³ ]} ( 11)

In order to evaluate the state in which the deflection amount y becomes maximum when the load P is applied in the equation (11), the equation (12) is derived by substituting y for Y _max and x for L, Equation (1) is obtained from (12).
Y _max =(64P/Eπ)·{(D·L+d ₁ )/[6(D) ³ (d ₁ +D·L) ² ]}-[2(D) ³ ·(d ₁ +D·L)] ^{− 1} +{(2D·L ² −d ₁ ·L)/[6(d ₁ ) ³ ·(D) ² ]}+{(2d ₁ −D·L)/[6(d ₁ ) ² (D) ³ ]}
_{^{= (64P / Eπ) · {}} [-3 (D) 3 · (d 1 + D · L)] -1 + [(D) 2 · (L) 2 -d 1 · L · D + (d 1) 2] /[3(d ₁ ) ³ ·(D) ³ ]} (12)

In order to set the elastic modulus E of the core base member in the above-mentioned predetermined range, for example, the material and dimensions (diameter, length) of the core base member, the type of synthetic resin in the resin material forming the base member, It is necessary to appropriately select the type of filler, the content in the resin material, and the like.

The feature of the present invention based on the above-mentioned formula (1) is configured by a base material portion having a core base material portion and a cleaning soft portion which covers the tip side (first shaft portion) of the core base material portion. Any interdental cleaning tool provided with a cleaning unit can be applied without particular limitation. That is, the cleaning unit to which the features of the present invention are applied is not limited to the one having the cleaning unit recess.

Hereinafter, the resin material forming the base material portion of the interdental cleaning tool of the present invention and the elastomer forming the soft portion will be described. The resin material forming the base material portion includes a synthetic resin, preferably a synthetic resin and at least one filler selected from the group consisting of fibrous fillers and plate-like fillers, and more preferably synthetic resin. And a plate-like filler or a plate-like filler and a fibrous filler, more preferably a synthetic resin and a plate-like filler.

As the synthetic resin, a synthetic resin commonly used in the field of interdental cleaning tools can be used without particular limitation, for example, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene, polyamide, polycyclohexylene dimethylene terephthalate, saturated polyester resin, Examples thereof include thermoplastic resins such as polymethyl methacrylate, cellulose propionate, thermoplastic polyurethane, polycarbonate, and ABS (acrylonitrile/butadiene/styrene) resin.

Among the above-mentioned thermoplastic resins, from the viewpoint of preventing breakage of the cleaning part, polypropylene, polybutylene terephthalate, thermoplastic resins having a melting point of 150° C. or higher such as polyamide are preferable, and from the viewpoint of preventing breakage of the cleaning part and molding processability. , Polypropylene, polybutylene terephthalate, and the like, more preferably a thermoplastic resin having a melting point of 150° C. or higher and at least a part of which is crystalline, and polypropylene is even more preferable. Polypropylene is particularly preferable because it has a low molding temperature, can shorten the cycle time to improve the productivity, and has a small heat load on the molding equipment. When a thermoplastic resin having a melting point of 150° C. or higher is used as the synthetic resin, it is possible to shorten the molding time of the base material part, particularly the cooling time after molding, and improve the production efficiency. As a result, the productivity of the interdental cleaning tool Can be improved, which in turn can reduce the production cost of the interdental cleaning tool. The selection of the type of thermoplastic resin is one of the means for imparting the above-mentioned predetermined elastic modulus to the cleaning portion. The thermoplastic resins may be used alone or in combination of two or more as required.

The fibrous filler is an inorganic compound having a fibrous or columnar or whisker shape and a dimension of millimeter order to micron order, and its aspect ratio is preferably 2 or more, more preferably 5 or more, further preferably 10 or more. Is. The fibrous filler is not particularly limited, but from the viewpoint of safety and easy availability to the human body, glass fiber, wollastonite, potassium titanate fiber, etc. can be preferably used, and further considering the price, etc., glass Fibers and wollastonite are more preferred, and glass fibers are even more preferred. The fibrous filler is preferable to the plate-like filler from the viewpoint of increasing the rigidity of the base material part, particularly the core base material part, and particularly the rigidity of the core base material part in the axial direction. The fibrous filler may be used alone or in combination of two or more as necessary.

The plate-like filler is an inorganic compound having a plate-like shape and dimensions on the order of microns. The plate-like shape includes a scale-like shape and a flaky shape. The plate-like filler is not particularly limited, and known ones can be used, but appropriate rigidity to the core base material portion (particularly the tip side shaft portion described later) (in particular, rigidity in the axial direction of the core base material portion) and From the viewpoints of imparting flexibility, safety to the human body, availability, etc., for example, glass flakes, mica, clay, talc and the like are preferable, clay and talc are more preferable, and talc is further preferable. The plate-like filler is preferable to the fibrous filler from the viewpoint of enhancing the flexibility of the core base material portion. The plate-like filler may be used alone or in combination of two or more.

Further, in the present invention, the fibrous filler and the plate-like filler can be used together. In this combined use, by appropriately selecting the use ratios of the fibrous filler and the plate-like filler, the orientation directions of the fibrous filler and the plate-like filler in the resin molded product are different, and the core substrate Since it is possible to improve the rigidity of the core base material while maintaining the flexibility of the core to such an extent that the core base material is unlikely to break, the core base material can be formed around the recess by forming the core base material recess. The decrease in rigidity can be compensated. Specific examples of the combined use include, for example, combined use of glass fiber and talc. In the combined use of glass fiber and talc, for example, by using more talc than glass fiber, it is possible to maintain flexibility of the core base material and improve mechanical properties.

In the resin material constituting the base material part, the content of the filler is not particularly limited, for example, imparting appropriate rigidity and appropriate flexibility to the base material part, especially the core base material part, and the elasticity of the core base material part. From the viewpoint of adjusting the rate E to the above-mentioned predetermined range, it is preferably selected from the range of 5 to 50% by weight, and more preferably 10 to 45% by weight of the total amount of the resin material. When polypropylene is used as the synthetic resin, the content of the plate-like filler is more preferably 20 to 45% by weight, particularly preferably 30 to 40% by weight based on the total amount of the resin composition. Further, when polybutylene terephthalate is used as the synthetic resin, the content of the plate-like filler is more preferably 15 to 45% by weight, particularly preferably 18 to 30% by weight based on the total amount of the resin composition. The content of the filler, particularly the plate-like filler, is selected so that the elastic modulus E of the core base material portion obtained from the equation (1) is 3000 MPa or more, preferably 3000 MPa or more and 7200 MPa or less, more preferably 3000 MPa or more and 6500 MPa or less. , More preferably 3500 MPa or more and 6000 MPa or less 7, and particularly preferably 4000 MPa or more and 6000 MPa or less.

It is preferable that the resin material forming the base material portion and the elastomer forming the soft portion described later have compatibility with each other. In this case, a more integrated structural change between the first shaft portion of the core base material portion and the cleaning soft portion is likely to occur, and peeling of the cleaning soft portion from the first shaft portion of the core base material portion occurs. Can be effectively prevented, so that the breakage resistance of the cleaning portion and the durability of the interdental cleaning tool can be further enhanced.

As the elastomer constituting the soft portion, a thermoplastic elastomer such as styrene-based, olefin-based or polyamide-based, or a thermosetting elastomer such as silicone rubber, urethane rubber, fluororubber, natural rubber or synthetic rubber can be used. In particular, a material having compatibility with the synthetic resin material forming the base material portion is preferable, and for example, when the base material portion is formed of polypropylene, it is preferable that the soft portion is formed of a polyolefin-based elastomer or a styrene-based elastomer. ..

Examples of other preferable elastomers include elastomers having a Shore A value of 5 to 70, preferably 10 to 50, more preferably 20 to 50, and further preferably 30 to 40. As a specific example of the elastomer having such a Shore A value, for example, a styrene-based elastomer having high flow properties even in a low hardness grade and good adhesive properties with a synthetic resin as compared with an olefin-based elastomer can be given. To be By designing the elastomer that constitutes the soft portion as described above, the soft portion hardly affects the predetermined bending amount Y _{max of the} core base material portion, and Y _max and the cleaning portion It has been found from the study by the present inventors that the predetermined deflection amount Z _max substantially corresponds to the predetermined deflection amount Z _max .

As described above, in order to set the elastic modulus E of the core base material portion obtained from the formula (1) to 3000 MPa or more, the proximal end diameter d _{1 of} the first shaft portion and the diameter d ₂ at the load position are set. In addition, the position where a load is applied on the first shaft portion is at a position having a length L (mm) from the boundary between the first and second shaft portions (that is, L (from the base end of the first shaft portion toward the tip side). (mm position) and it is necessary to appropriately select the type of synthetic resin, the type of filler, the content, etc. of the resin material forming the base material portion, which influences the maximum deflection amount Y _max. is there. In addition, the length of the first shaft portion, the proximal end diameter d ₁ and the diameter d ₂ at the load position may also affect Y _max .

In particular, by setting the length L to preferably 3 mm or more and 12 mm or less, more preferably 4 mm or more and 11 mm or less, still more preferably 5 mm or more and 10 mm or less, and particularly preferably 10 mm, the fluctuation width of the elastic modulus E is reduced, and it is almost accurate. The elastic modulus E can be obtained with good reproducibility. Then, the characteristics of the interdental cleaning tool can be known almost accurately from the obtained elastic modulus E.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view schematically showing a configuration of an interdental cleaning tool connected body 1A. 2A and 2B are schematic diagrams showing a configuration of a main part of the interdental cleaning tool connected body 1A, in which FIG. 2A is a front view and FIG. 2B is a side view. FIG. 3 is an enlarged schematic front view of the vicinity of the connecting portion 13 of the interdental cleaning tool connected body 1A. FIG. 4 is a cross-sectional view taken along the line IV-IV shown in FIG. FIG. 5 is an enlarged schematic view of the cleaning unit 2 provided in the interdental cleaning tool 1, where (a) is a front view and (b) is a side view. FIG. 6 is a cross-sectional view taken along the line VI-VI shown in FIG.

As shown in FIGS. 1 and 2, the interdental cleaning tool 1 of the present embodiment is provided with a cleaning unit 2 for interdental cleaning and a handle unit 3 as a handle, and is configured according to its function. When the materials are distinguished, a base portion 10 made of a resin material containing a synthetic resin and a soft portion 20 made of an elastomer are provided.

The interdental cleaning tool 1 is formed, for example, in the form of an interdental cleaning tool connection body 1A in which a plurality of interdental cleaning tools 1 are detachably connected in parallel by a connecting portion 13, and the user The interdental cleaning tool 1 is sequentially separated from the one end of the inter-cleaning tool connecting body 1A at the connecting portion 13 and used sequentially. In addition, FIG. 1 only shows a configuration of a main part of the interdental cleaning tool connected body 1A, and the number of interdental cleaning tools 1 connected in parallel in the interdental cleaning tool connected body 1A is not particularly limited. It can be an arbitrary number.

Hereinafter, the interdental cleaning tool 1 will be described based on the division into the base material portion 10 and the soft portion 20.

The base material portion 10 is made of the above-described resin material, and as shown in FIGS. 1 to 4, a flat and slender plate-shaped handle base material portion 11 that constitutes the handle portion 3 that serves as a handle, and a handle base material portion. An elongated shaft-shaped core base material portion 12 that is continuously provided at the tip end portion of 11 and a connection portion 13 that detachably connects the handle base material portions 11 that are adjacent in the width direction.

The handle base 11 is formed in a flat plate shape in the present embodiment, but any shape other than the flat plate shape, such as a circular shape or an oval shape, can be used as long as it is easy to hold the space between the teeth by cleaning with a finger. Shape (oval, oval, rounded rectangle, oval, oval, bale shape (rectangular with short sides, rounded rectangle), rod-shaped cross section such as teardrop or polygon It can be formed into a flat plate shape such as a circular shape, an oval shape, or a polygonal shape. In order to improve the ease of holding, the handle base member 11 may be provided with a curved portion, a concave portion, a convex portion, a cutout portion, or the like. Further, the handle base material portion 11 of the present embodiment is configured such that the tip end portion thereof becomes narrower toward the core base material portion 12 side, and is smoothly connected to the core base material portion 12.

The size of the handle base 11 can be set to any size as long as it can be easily held by fingers and cleaned between teeth, and the handle base 11 having the shape shown in FIGS. L1 can be set to 10 mm to 25 mm, width W1 can be set to 4 mm to 10 mm, and the thickness t1 of the grip portion can be set to 1.0 mm to 2.0 mm. When the handle base material portion 11 is thin as described above, when the base material portion 10 is molded, dimensional variation due to shrinkage of the handle base material portion 11 can be reduced, sink marks are prevented, and the soft portion 20 is molded. Therefore, it is possible to prevent the defective loading of the base material portion 10 into the second mold.

The core base material portion 12 is formed in a substantially linear elongated shaft shape, and has a second shaft portion (exposed portion) 12a continuously provided on the tip end side of the handle base material portion 11 and a tip end side of the second shaft portion 12a. And a first shaft portion 12b (hereinafter may be referred to as a "core body 12b") connected to the. The first shaft portion 12b is covered with the cleaning soft portion 21. The core base material portion 12 of the present embodiment is formed in a gentle taper shape in which the diameter is reduced toward the distal end side, but the present invention is not limited to this, and the second shaft portion 12a has a shaft of substantially the same diameter over its entire length. The first shaft portion 12b may be formed into a tapered shape in which the diameter of the first shaft portion 12b is gradually reduced toward the distal end side. Further, the second shaft portion 12a and the first shaft portion 12b may be formed in the entire length thereof. The diameter may be substantially the same.

The length L2 of the second shaft portion 12a in the core substrate portion 12 is, for example, 10 mm to 40 mm, preferably 10 mm to 30 mm, more preferably 10 mm to 25 mm, in consideration of the operability of the interdental cleaning tool 1. Most preferably, it is set to 10 mm to 20 mm. Here, the second shaft portion 12a extends from the end point of the curved portion on the side surface of the distal end portion configured to be narrow in the handle base material portion 11 to the end of the proximal end portion of the soft portion 21 for cleaning (or the first shaft portion 12b). Say. The cross-sectional shape of the second shaft portion 12a is preferably circular from the viewpoints of insertability between the teeth of the cleaning unit 2 and relaxation of stress concentration, but may be oval shape, teardrop shape, polygonal shape, or the like.

On the other hand, the length L3 of the first shaft portion 12b covered with the cleaning soft portion 21 starts from the boundary between the first and second shaft portions 12b and 12a when determining the cleanability between teeth and the elastic modulus E. In consideration of the fact that a load is applied to the end side of the first shaft portion 12b at a position of length L (mm), and the length L is preferably selected from the range of 3 mm to 12 mm, the above formula (1 The elastic modulus E calculated from (1) may be appropriately selected so as to be 3000 MPa or more, preferably 3000 to 7200 MPa, more preferably 3000 to 6500 MPa, further preferably 3500 to 6000 MPa, and particularly preferably 4000 to 6000 MPa. As a guide, for example, the range is 12 mm to 22 mm. The diameter of the tip side portion of the first shaft portion 12b is selected from the range of 0.4 mm to 0.6 mm, for example, and the diameter of the base end side portion of the first shaft portion 12b is 0.8 mm to 2.0 mm. Selected from the range. The first shaft portion 12b can also have the same cross-sectional shape as the second shaft portion 12a.

Further, the diameter D at the curved end portion of the tip end portion of the first shaft portion 12b covered by the cleaning soft portion 21 and the proximal end side end diameter d _{1 of the} core base material portion obtained from the above formula (1). A value that allows the elastic modulus E to fall within the above-described predetermined range may be appropriately selected, and the standard of each selection is, for example, 0.5 to 1.2 mm and 0.3 to 0.8 mm. By setting the diameter D of the first shaft portion 12b within the above range, it is possible to reliably insert a region of at least 5 mm or more from the distal end portion between the teeth.

In addition, the elastic modulus E of the core base material portion of the first shaft portion 12b, which is obtained from the equation (1), is set within the above predetermined range, and the proximal end diameter d _{1 of} the first shaft portion 12b>the load load By adjusting the diameter d ₂ at the position and appropriately adjusting the ratio (d ₁ /d ₂ ), it is possible to further improve the interdental insertability of the cleaning unit 2 and the breakage resistance during interdental cleaning. .. The diameter ratio (d ₁ /d ₂ ) is preferably 1.5 to 3.0, more preferably 1.8 to 2.5, and further preferably 2.0 to 2.4.

Further, the angle θ1 formed by the tapered shape with respect to the center line of the core base material portion 12 is set to, for example, 0.2° to 1.5° in consideration of insertability between the cleaning portion 2 between the teeth and the like. In the present embodiment, the angle θ is set to be substantially the same over the entire length of the core base material portion 12, but the present invention is not limited to this, and the angle θ may be continuous or stepwise toward the tip side of the core base material portion 12. It can also be set to be smaller.

In the present embodiment, the present invention is applied to the I-shaped interdental cleaning tool 1 in which the center line extending in the longitudinal direction of the handle base 11 and the axis of the core base 12 are arranged in substantially the same axis. However, the present invention can also be applied to an interdental cleaning tool in which the center line of the handle base material portion 11 and the axis of the core base material portion 12 are arranged in an arbitrary positional relationship. The present invention can be applied to an interdental cleaning tool in which a line and an axis of the core base 12 are arranged in parallel with each other with a space therebetween, and the center line of the core base 12 is the centerline of the handle base 11. On the other hand, for example, a so-called L-shaped interdental cleaning tool 1 provided at an angle of 90° to 120°, a handle portion connected to the cleaning portion, or the like has a smooth curved shape of about 140° to 160°. The present invention can be applied to a curved interdental cleaning tool that the user has.

As shown in FIGS. 2 to 4, the connecting portion 13 is integrally formed with the handle base material portion 11 between the adjacent handle base material portions 11, and the base end portion side and the tip end portion side of the handle base material portion 11 are formed. And a pair are provided at intervals in the longitudinal direction. The connecting portion 13 is elongated in the axial direction of the handle base material portion 11, and is formed in a trapezoidal shape in a front view (isopodal trapezoidal shape in FIG. 3 ). The number of the connecting portions 13 can be set arbitrarily, and it is possible to provide only one. However, with such a configuration, the connecting strength between the adjacent base material portions 10 is sufficiently high when the interdental cleaning tool 1 is molded. Cannot be ensured, the connecting part 13 is broken when the mold is opened after the base part 10 is molded, and the base part 10 is disjointed, and the soft part 20 cannot be formed. Since the base member 10 is bent and the base member 10 cannot be loaded at an appropriate position in the second molding space for molding the soft part 20, a molding defect may occur. It is preferable to provide two or more holes apart.

The cross section of the connecting portion 13 is formed in a trapezoidal shape or a triangular shape (in FIG. 4, an isosceles trapezoidal shape or an isosceles triangular shape), and as shown by a virtual line in FIG. By bending the cleaning tools 1 in the direction in which they are superimposed on each other to concentrate the bending force on the boundary portion 13a, the arcuate side surface 11a of the side edge of the handle base material portion 11 contacts the outer surface of the connecting portion 13, According to the principle of leverage, a large force is applied to the boundary portion 13a in a direction of separating the boundary portion 13a, so that the interdental cleaning tool 1 can be neatly separated without a large deformation of the connecting portion 13 at the boundary portion 13a. Has been done. However, the shape of the connecting portion 13 is optional as long as it is configured to be easily and cleanly separated by bending the interdental cleaning tools 1 adjacent to each other around the connecting portion 13 in a direction in which they are overlapped with each other. Can be formed in the shape of.

As shown in FIGS. 1 to 4, the soft part 20 is integrally molded with the core base material part 12 of the base material part 10 by using an elastomer, and is mounted on the first shaft part 12b of the core base material part 12. A soft part 21 for cleaning is provided. However, as the soft portion 20, the second shaft portion 12a is located between the base end portion of the first shaft portion 12b (that is, the first shaft portion 12b near the boundary between the first shaft portion 12b and the second shaft portion 12a). It is also possible to provide a ring-shaped entry regulation restricting portion for restricting entry into the vehicle or to provide a slip prevention portion on the handle base material portion 11. The entry restricting portion and the anti-slip portion can be formed independently of the cleaning soft portion 21, but since the structure of the mold used for molding the interdental cleaning tool 1 becomes complicated, the cleaning soft portion 21 It is preferable to perform molding so as to be continuous with the base end portion of the portion 21 or simultaneously with the soft cleaning portion 21.

The cleaning soft portion 21 projects outward with a predetermined gap in the lengthwise and/or widthwise direction of the covering portion 21a covered by the first shaft portion 12b of the core base material portion 12 and the covering portion 21a. It has a plurality of protrusions 21b formed in a shape.

If the thickness of the covering portion 21a is too thick, it is necessary to reduce the diameter of the first shaft portion 12b covered by the covering portion 21a, so that the rigidity of the cleaning portion 2 and thus the interdental insertability thereof are reduced. However, Karman vortices are likely to be generated at the time of molding, and there is a risk that the Karman vortices will be greatly affected. If the covering portion 21a is too thin, it becomes difficult to form the covering portion 21a up to the base end side of the first shaft portion 12b, and the covering portion 21a may be separated from the first shaft portion 12b. Therefore, the thickness of the covering portion 21a is selected from the range of 0.1 mm to 0.2 mm, for example.

The protruding portion 21b is provided so as to protrude outward from the surface of the covering portion 21a. The plurality of protrusions 21b can be arranged in an arbitrary pattern on the surface of the cover 21a. For example, a plurality of protrusions 21b arranged in a row in the length direction of the cover 21a at a predetermined pitch. A plurality of array patterns provided in the circumferential direction of the coating portion 21a, a plurality of array patterns in which a plurality of protrusions 21b arranged in the circumferential direction of the coating portion 21a at a predetermined pitch are provided in the longitudinal direction of the coating portion 21a, Further, an array pattern in which a plurality of protrusions 21b are irregularly arranged can be cited.

The cross-sectional area, length, number, and arrangement pitch of the base end portions of the protrusions 21b can be set arbitrarily, but in consideration of moldability, cleanability, etc., the cross-sectional area of the base end portion of the protrusions 21b. is ^preferably set to about 0.03 mm 2 1.5 mm ^2, more preferably 0.03 mm 2 1.0 mm ^2, and most preferably 0.04 mm 2 to 0.8 mm ^2. The length of the cleaning protrusion 21b is preferably set to about 0.1 mm to 2.5 mm, more preferably set to 0.3 mm to 2.0 mm, and set to 0.5 mm to 1.7 mm. Is more preferable. The number of the protrusions 21b is preferably set to 20 to 100, and the arrangement pitch of the protrusions 21b is preferably set to 0.5 mm to 1.5 mm. Further, the projection 21b of the present embodiment has a conical shape, but is not limited to this, and for example, a flat plate-like tapered shape that is flat in the axial direction may be employed. Further, as the cross-sectional shape of the protruding portion 21b, in addition to the circular shape, an arbitrary shape such as an oval shape, a teardrop shape, or a polygonal shape can be adopted.

As shown in FIGS. 5 and 6, the covering portion 21a has a plurality of covering portion recesses 14b. The covering portion recess 14b penetrates the covering portion 21a in the thickness direction in a region where the protrusion 21b of the covering portion 21a is not formed, and is connected to the core base material portion recess 14a formed on the surface of the core base material portion 12. .. That is, the soft portion 20 has the cleaning portion recess 14 integrally formed with the coating portion recess 14b penetrating the coating portion 21a and the core base material portion recess 14a connected to the coating portion recess 14b. The cleaning portion recess 14 has a positioning pin abutting against the core base material portion 12 in order to prevent the core base material portion 12 from being displaced when the soft base portion 12 is covered and molded. It is formed by injecting an elastomer in the state.

In the present embodiment, as shown in FIGS. 5 and 6, three covering portion recesses 14b are provided as the first and second covering portion recesses 14b on the first and second side portions of the covering portion 21a, respectively. The first and second covering portion recesses 14b on the first and second side portions at the same position in the axial direction of the core base material portion 12 are arranged face to face with the core base material portion 12 interposed therebetween. Therefore, in the present embodiment, the pair of first and second covering portion recessed portions 14 b arranged at positions facing each other with the core base material portion 12 interposed therebetween are spaced apart by three in the axial direction of the core base material portion 12. It is provided in place. The number of the pair of first and second recesses 14b for the covering portion, which are arranged so as to face each other, is not particularly limited, and may be one or more, but is preferably 2 or more, more preferably 3 to 4 or more. Is.

By setting the number of the pair of first and second covering portion recesses 14b, and by extension, the cleaning portion recess 14 to 3 to 4 or more, the bending stress acting on the cleaning portion 2 during interdental insertion or interdental cleaning is dispersed. In addition, while the holdability of the core base material portion 12 by the holding pin is secured, the depth of the core base material recessed portion 14a is made shallow, so that a large bending stress locally acts during cleaning between teeth. By doing so, it is possible to effectively prevent the core substrate portion 12 from being broken.

The disposition intervals of the covering part recesses 14 with respect to the axial direction of the core base material part 12 may be all set to the same intervals, or some or all may be set to mutually different intervals. For example, the arrangement interval can be narrowed or widened toward the tip side of the cleaning unit 2 including the core base member 12 and the cleaning soft portion 21, but the arrangement interval is It is preferable to set it to be substantially uniform or to become narrower toward the tip side of the cleaning unit 2.

As described above, it is preferable that the pair of first and second covering portion recesses 14b (or the pair of cleaning portion recesses 14) be arranged face-to-face, but within the range where they partially overlap in the circumferential direction, that is, the core. It may be provided at a position shifted in the axial direction of the core base material portion 12 within the range of the length of the covering portion recess 14b with respect to the axial direction of the base material portion 12. Further, as shown in FIG. 6, it is preferable that the first covering portion concave portion 14b on the first side portion and the second covering portion concave portion 14b on the second side portion are arranged on the same axis, but the first covering portion concave portion The center line of 14b and the center line of the second coating portion recess b may be arranged in parallel with each other with a certain distance offset in the radial direction of the cleaning unit 2.

When the cleaning portion recess 14 is formed in an elongated shape such as an oval shape, a teardrop shape, or a rectangle, for example, as in the cleaning portion 2A shown in FIG. It is preferable to form between the adjacent protrusions 21b so that the longitudinal direction is the axial direction of the cleaning portion 2A (or the core base material portion 12). That is, the cleaning portion recess 14A is a recess that is long in the axial direction of the cleaning portion 2A (or the core base material portion 12). According to this structure, the width of the cleaning portion recess 14A is narrowed to reduce the width of the holding pin, while the holding property of the holding pin with respect to the core base portion 12 is sufficiently ensured, the core base portion recess 14Aa. It is preferable because the stress generated at the position where is provided can be relaxed.

It is also preferable that the bottom surface of the core base material recess 14a located at the bottom of the cleaning recess 14 is a flat surface in a direction orthogonal to the depth direction of the core base recess 14a as shown in FIG. , A core base material recess 14Ba of the cleaning base recess 14B shown in FIG. 8, or an arc surface along the outer surface of the core base 12, or a core base recess of the cleaning base recess 14C shown in FIG. Like 14Ca, it can be constituted by two isosceles triangular inclined surfaces with a raised central portion.

The interdental cleaning tool 1 is manufactured by a two-color molding method using, for example, two molds, as in the conventional resin interdental cleaning tool. That is, a first mold having a molding space corresponding to the three-dimensional shape of the base material portion 10 is used, and a melt-kneaded product of a resin material is injected into the molding space of the first mold and cooled to obtain the base material portion 10. Next, a second mold having a molding space corresponding to the three-dimensional shape of the interdental cleaning tool 1 is used, and the melted material of the elastomer is placed in the molding space of the second mold in which the obtained base material portion 10 is loaded at a predetermined position. The interdental cleaning tool 1 can be obtained by injecting or injecting a thermosetting elastomer, heating and then cooling and integrally molding the soft part 20 on the base material part 10.

Further, a resin composition is used in the plurality of first molding spaces, using a first mold having a plurality of first molding spaces and a second mold having a same number of second molding spaces as the first molding spaces. To produce a primary molded product in which a plurality of base material parts are connected by a runner part, and the primary molded product is loaded into a second molding space of a second mold to form a plurality of second molding spaces. By supplying the elastomer, it is possible to obtain an interdental cleaning tool connected body in which a plurality of interdental cleaning tools are simultaneously molded.
Note that such a two-color molding method for the interdental cleaning tool 1 is known and is described in, for example, International Publication No. 2013/176297.

Next, the evaluation test of the interdental cleaning tool will be described based on the following test examples.

(Production of base material and interdental cleaning tool)
First, 13 kinds of resin materials (Examples 1 to 7 and Comparative Examples 1 to 6) containing polypropylene and talc and varying the content of talc were prepared. Using each of the obtained resin materials, the total length is 48 mm, the size of the handle base material part is 15 mm (maximum width) x 6.5 mm, the size of the second shaft part of the core base material part is 18 mm in length and 1.2 mm in diameter. A certain base material portion shown in FIG. 1 was produced. The first shaft portion has a tapered shape in which the diameter gradually decreases from the base end side toward the tip end side. Further, the core base material portions of the base material portions of the obtained Examples 1 to 7 and Comparative Examples 1 to 6 were coated and molded with polystyrene elastomer to form a cleaning portion, and Examples 1 to 7 and Comparative Examples 1 to 1 were formed. Six interdental cleaning tools were produced.

According to the compression test using the above-described precision universal testing machine, the proximal end diameter d _{1 of} the first shaft portion and the diameter d ₂ at the load position were measured with a caliper, and L was set to 5 mm or 10 mm. After that, a load (P) is applied at a position of L (mm) from the boundary position of the first and second shaft portions to the tip side of the first shaft portion, and the load displacement of each core base material portion and each cleaning portion is changed. The curve was determined. Seeking Y _max of Shinmoto material portion from the obtained load-displacement curve was determined modulus based on the formula (1) (E). Further, similarly, _Zmax (not shown in Tables 1 and 2) of the cleaning portion was obtained, and the elastic modulus (E) was obtained based on the equation (1). The results are shown in Tables 1 and 2.

(Folding resistance test of cleaning part)
Using a compression tester (precision universal tester, manufactured by Shimadzu Corporation), the cleaning portion of the interdental cleaning tool of Examples 1 to 7 and Comparative Examples 1 to 6 obtained above was inserted at an insertion angle of 50°. Alternatively, it was inserted between the first and second molars of a jaw model (manufactured by Nissin Co., Ltd.) at an insertion rate of 200 mm/min at 60°. This insertion test was performed three times, and the state of the cleaning part of each interdental cleaning tool was visually observed and evaluated according to the following criteria. The evaluation results are shown in Tables 1 and 2.

[Evaluation criteria]
Acceptable: No breakage (breakage) of the cleaning portion was observed in the three insertion tests, but deformation of the cleaning portion was observed even once.
No; breakage (breakage) of the cleaning part was recognized even once in the three insertion tests.

From Table 1 and Table 2, regarding the core base material portion, the elastic modulus E obtained from the equation (1) and the theoretical value of the elastic modulus were substantially the same. Further, it is clear that an interdental cleaning tool having a cleaning portion excellent in bending resistance can be obtained by adjusting the elastic modulus E of the core base material portion obtained from the formula (1) so as to fall within a predetermined range. Is.

Next, polypropylene was mixed with glass fiber, the content of glass fiber was changed, and seven kinds of resin materials having different elastic moduli (theoretical values) were produced. Using these resin materials, the base material portions of Examples 8 to 14 were produced in the same manner as in Example 1. With respect to each of the three base members, the load position L10 mm was set, and the proximal end diameter d ₁ (mm) of the first shaft part and the diameter d ₂ (mm) at the load position were measured with a caliper. The elastic modulus E was calculated by calculating _Ymax from the load displacement curve obtained by subjecting the compression test using the above-described precision universal tester. The results are shown in Table 3. In addition, the linear region is 20 to the maximum load value in each load displacement curve based on the experimental results (here, not the load value when the deflection amount Y _max is obtained, but the largest load value in the load displacement curve). The load range of 40% was defined and extracted.

It can be seen from Table 3 that even if the elastic modulus of the resin material is changed by using glass fiber, a base material portion having a desired elastic modulus (E) can be obtained. With respect to the base material portion of Example 1, the average elastic modulus of three samples was further calculated to be 5882 MPa, which is a good reproduction for calculating Y _max based on the load deformation curve and calculating the elastic modulus E based on the equation (1). It turned out that there is a nature. In order to further increase the accuracy of the calculated elastic modulus E, it is possible to individually obtain the load displacement curve and the elastic modulus E for three or more samples (preferably 11 samples) and use them as the average value. preferable. Moreover, when a sufficient test range (for example, in terms of the length of the first shaft portion) cannot be obtained with the first shaft portion, the measurement can be performed with the second shaft portion.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that the configuration can be appropriately changed without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Interdental cleaning tool 1A Interdental cleaning tool connection body 2, 2A Cleaning part 3 Handle part 10 Base material part 11 Handle base material part 12 Core base material part 12a Base end side shaft part 12b Tip side shaft part 13 Connecting part 14, 14A, 14B, 14C Cleaning part recessed part 14b Covering part recessed part 14a, 14Aa, 14Ba, 14Ca Core base material part recessed part 20 Soft part 21 Cleaning soft part 21a Covering part 21b Projection part

Claims (11)

A handle base material portion that serves as a handle and an elongated shaft-shaped core base material portion that is continuously provided on the distal end side of the handle base material portion, and a base material portion made of a resin material containing a synthetic resin; An interdental cleaning tool including a cleaning soft part having a coating part that covers at least a part of a material part, and a soft part made of an elastomer,
The core base material portion is connected to the first shaft portion covered with the cleaning soft portion, one end of which is substantially coaxial with the first shaft portion, and the other end of which is on the distal end side of the handle base material portion. A second shaft portion that is continuously provided, and the first shaft portion has a proximal end diameter of d ₁ (mm),
A boundary position between the first shaft portion and the second shaft portion in a state in which the interdental cleaning tool is held in the horizontal direction with the proximal end of the first shaft portion as a fixed end and the distal end of the first shaft portion as a free end. In the measurement in which the load (P) is vertically downwardly applied at a position of L (mm) toward the tip side of the first shaft portion with the origin as a starting point, the maximum load in the load region where the first shaft portion maintains elastic deformation. When the deflection amount when the value is applied as the load (P) is Y _max (mm) and the diameter of the first shaft portion at the position where the load (P) is applied is d ₂ (mm), the following formula ( An interdental cleaning tool characterized in that the elastic modulus E of the core base material portion obtained from 1) is 3000 MPa or more.
E=[64P/(Y _max ·π)]·(m+n) (1)
Wherein ^{(1), m = - [} 3 · (D) 3 · (d 1 + D · L)] ^-1.
n ⁼ a ^{_{[D 2 · L 2 -d 1}} · L · D + (d 1) 2] / [3 · (d 1) 3 · (D) 3]. In the above formulas, D=(d ₂ −d ₁ )/L. ] The interdental cleaning according to claim 1, wherein the cleaning soft portion further includes a plurality of protruding portions that are integrated with the covering portion so as to project outwardly at intervals in the longitudinal direction of the covering portion. Ingredient The interdental cleaning tool according to claim 1 or 2, wherein the L is 3 mm or more and 12 mm or less. The interdental cleaning tool according to any one of claims 1 to 3, wherein the elastic modulus E of the core base material portion is in a range of 3000 MPa or more and 7200 MPa or less. The core base has two or more core base recesses at predetermined positions on its surface, and the covering has a first side and a second side, and the first and second sides are provided. The section has two or more first and second coating section recesses which are arranged at predetermined intervals in the axial direction of the cleaning section and penetrate the coating section and are connected to the core base material section recess. Item 6. The interdental cleaning tool according to any one of Items 1 to 4. The interdental cleaning according to claim 5, wherein the two or more first recesses of the first coating portion and the two or more recesses of the second coating portion are arranged in face-to-face relation with the core base material portion interposed therebetween. Ingredient The interdental cleaning tool according to claim 5 or 6, wherein at least one of the first and second covering portion recesses is a recess that is long in the axial direction of the core base material portion. The tooth according to any one of claims 1 to 7, wherein the first shaft portion has the d ₁ >the d ₂ and has a tapered shape in which the diameter gradually decreases from the base end side toward the tip end side. Inter-cleaning tools. The tooth according to any one of claims 1 to 8, wherein the resin material contains the synthetic resin and at least one kind of filler selected from the group consisting of fibrous fillers and plate-like fillers. Inter-cleaning tools. The interdental cleaning tool according to claim 9, wherein the filler is a plate-like filler or a mixture of a plate-like filler and a fibrous filler. The interdental cleaning tool according to any one of claims 1 to 10, wherein the synthetic resin is a thermoplastic resin having a melting point of 150°C or higher.

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