JP2018068512A - Interdental brush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interdental brush whose handle portion is less fatigable even when bent repeatedly.SOLUTION: An interdental brush 1 includes: a handle portion 10 formed from a polyolefin resin; and a brush portion 100 joined to the handle portion 10 for cleaning of an interdental space. The density of the polyolefin resin is within a range of 920-930 kg/m. The melting point of the polyolefin resin is within a range of 120-126°C.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an interdental brush used for cleaning between teeth.

  The interdental brush includes a handle portion including a grip portion for the user to grip, a core member joined to the handle portion, and a filament bundle planted in the core member. The handle portion may be bent to adjust the insertability of the filament bundle between the teeth. Patent Document 1 discloses an example of a conventional interdental brush.

JP 2005-224268 A

According to the conventional interdental brush, when the handle portion is repeatedly bent, the handle portion may be fatigued. In addition, it is related to the fatigue of the handle part that the handle part is bent beyond the yield point of the resin material constituting the handle part so that the handle part is kept bent during cleaning between the teeth. ing.
An object of the present invention is to provide an interdental brush in which a handle portion is not easily fatigued even when it is repeatedly bent.

(1) One form of an interdental brush according to the present invention includes a handle portion made of a polyolefin resin, and a brush portion joined to the handle portion so that the interdental space can be cleaned, and the density of the polyolefin resin is , 920 to 930 kg / m ³ , and the polyolefin resin has a melting point in the range of 120 to 126 ° C.
When the density and melting point of the polyolefin resin are included in the above ranges, it was confirmed by a test that the handle portion is not easily fatigued.

(2) In one example of the interdental brush, the elastic modulus of the polyolefin resin is included in a range of 200 to 300 MPa.
When the elastic modulus of the polyolefin resin is included in the above range, it was confirmed by a test that the handle part is less fatigued.

(3) In an example of the interdental brush, the handle portion includes a planned bending portion configured to be bent in order to adjust insertion property of the brush portion between the teeth.
For this reason, a handle | steering-wheel part can be bent easily.

(4) In one example of the interdental brush, the handle portion includes a grip portion and a neck portion, and the grip portion and the neck portion are integrally formed of the polyolefin resin.
For this reason, an interdental brush can be manufactured efficiently.

(5) In an example of the interdental brush, the bent portion includes a first bent portion provided in the neck portion.
For this reason, a neck part can be bent easily.

(6) In an example of the interdental brush, the brush portion includes a core material and a bundle of filaments planted in the core material, and the first bent portion is the direction in which the brush portion falls down. A first groove configured to bend the neck portion is included.
For this reason, the direction in which the neck portion is bent is appropriately determined.

(7) In an example of the interdental brush, the bent portion includes a second bent portion provided in the grip portion.
For this reason, the attitude | position of a brush part can be adjusted more variously.

(8) In one example of the interdental brush, the second bent portion includes a second groove configured to bend the grip portion in a direction in which the brush portion is tilted.
For this reason, the direction in which the grip portion is bent is appropriately determined.

(9) In one example of the interdental brush, the brush part includes a core material and a filament bundle planted in the core material, and the core material includes at least a covering part coated on the neck part. The ratio of the thickness of the portion corresponding to the thinnest portion of the covering portion to the minimum dimension that is the dimension of the thinnest portion in the neck portion is included in the range of 15 to 45%.
When the ratio of the thickness of the covering portion to the minimum size of the neck portion is included in the range of 15% or more, the state where the neck portion is bent is easily maintained. When the ratio of the thickness of the covering portion to the minimum dimension of the neck portion is included in the range of 45% or less, the neck portion can be easily bent.

(10) According to an example of the interdental brush, the polyolefin resin is a polyethylene resin.
When the handle portion is made of polyethylene resin, it was confirmed by a test that the handle portion is less likely to be fatigued.

(11) According to an example of the interdental brush, the polyethylene resin is a linear low-density polyethylene resin.
When the handle portion is made of a linear low density polyethylene resin, it has been confirmed by a test that the handle portion is less fatigued.

  The interdental brush according to the present invention is less fatigued even when the interdental brush is repeatedly bent to deform into an optimal shape according to the position between the teeth to be cleaned. The optimal shape of the interdental brush is easily maintained. For this reason, between teeth can be efficiently cleaned by using this interdental brush for cleaning between teeth.

The perspective view of the 1st front side of the interdental brush of an embodiment. The perspective view of the 2nd front side of the interdental brush of FIG. The front view of the interdental brush of FIG. The side view of the interdental brush of FIG. The enlarged view of the neck part of FIG. 1 and its periphery. Sectional drawing which follows the D6-D6 line | wire of FIG. Sectional drawing which follows the D7-D7 line | wire of FIG. The enlarged view of the 2nd part of FIG. The enlarged view of the 2nd part of FIG. The side view regarding the 1st usage pattern of the interdental brush of FIG. The side view regarding the 2nd usage pattern of the interdental brush of FIG. The side view regarding the 3rd usage pattern of the interdental brush of FIG. The side view regarding the 4th usage pattern of the interdental brush of FIG. Sectional drawing of the mold clamped. Sectional drawing which shows the state by which the resin material was inject | emitted in the metal mold | die. The table | surface which shows the test conditions and measurement result regarding a 1st test. The table | surface which shows the test conditions and measurement result regarding a 2nd test. The graph which shows the relationship between the 1st deformation rate of FIG. 17, and maximum torque. The graph which shows the relationship between the 2nd deformation rate of FIG. 17, and maximum torque. The table | surface which shows the test conditions regarding a 3rd test, and a measurement result. The table | surface which shows the test conditions regarding a 4th test, and a measurement result.

(Embodiment)
With reference to FIGS. 1-3, the structure of the interdental brush 1 is demonstrated.
The interdental brush 1 includes a handle portion 10 and a brush portion 100. The handle portion 10 constitutes the main body of the interdental brush 1. The brush part 100 is joined to the handle part 10 so that the space between teeth can be cleaned. For the interdental brush 1, an axial direction, a width direction, and a thickness direction can be defined. The axial direction of the interdental brush 1 is a direction along the central axis C of the interdental brush 1. The width direction of the interdental brush 1 is a direction orthogonal to the axial direction of the interdental brush 1 in a front view of the interdental brush 1. The thickness direction of the interdental brush 1 is a direction orthogonal to the axial direction of the interdental brush 1 in a side view of the interdental brush 1. The structure of the interdental brush 1 is plane-symmetric with respect to a center plane D (see FIG. 4) parallel to the axial direction and the width direction of the interdental brush 1. The central axis C of the interdental brush 1 is included in the central plane D.

  The handle portion 10 includes a first front surface 10A (see FIG. 1), a second front surface 10B (see FIG. 2), a first end portion 10C, and a second end portion 10D. The first front surface 10A and the second front surface 10B are surfaces provided so as to sandwich the central axis C and the central surface D (see FIG. 4) of the interdental brush 1. The first end portion 10 </ b> C is one end portion of the handle portion 10 in the axial direction of the interdental brush 1. The second end portion 10 </ b> D is the other end portion of the handle portion 10 in the axial direction of the interdental brush 1. The shape of the first end portion 10C is approximately spherical. For this reason, when the first end portion 10C comes into contact with the tissue in the mouth, the impact can be reduced. The shape of the second end portion 10D is approximately hemispherical.

  The handle portion 10 further includes a neck portion 20, a grip portion 30, and a bending planned portion 40. The grip part 30 is a part configured so that the user can firmly grip with a finger. The neck portion 20 is a portion that is relatively narrower than the grip portion 30 so as not to come into contact with the tissue in the mouth. The neck portion 20 includes the first end portion 10 </ b> C of the handle portion 10. The grip part 30 includes a second end part 10 </ b> D of the handle part 10. The grip part 30 is configured so that the user can grip. The folding schedule part 40 includes a first folding schedule part 41 and a second folding schedule part 42.

  The first bending planned portion 41 is provided in the neck portion 20. The second bending scheduled portion 42 is provided in the grip portion 30. Each bending plan part 41 and 42 is comprised so that it can be bent in order to adjust the insertion property of the brush part 100 with respect to between teeth. Since the first bending scheduled portion 41 is provided in the neck portion 20, the neck portion 20 can be easily bent. Since the 2nd bending plan part 42 is provided in the grip part 30, the attitude | position of the brush part 100 can be adjusted more variously.

  The brush unit 100 includes a core material 110, a filament bundle 200, and a cleaning unit 140. The core material 110 holds the filament bundle 200. The cleaning unit 140 is a part directly involved in cleaning between teeth in the brush unit 100. The cleaning unit 140 includes a portion (hereinafter referred to as “holding unit 121”) in which the filament bundle 200 is implanted in the core material 110, and the filament bundle 200. The filament bundle 200 is composed of a plurality of filaments so that plaque and food residues can be removed from between the teeth. An example of the material constituting the filament is nylon resin and polybutylene terephthalate resin. The filament bundle 200 is planted in the core material 110 so as to protrude radially from the core material 110.

  The interdental brush 1 can take a plurality of usage forms. In each usage pattern, the handle portion 10 has a shape corresponding to a site between teeth to be cleaned. In one example, the plurality of usage patterns of the interdental brush 1 include first to fourth usage patterns.

  FIG. 10 is a side view of the interdental brush 1 taking the first usage pattern. The first usage pattern is a form suitable mainly for cleaning between the front teeth. In the first usage pattern, the planned bending portion 40 is not bent and the shape of the handle portion 10 is linear.

  FIG. 11 is an example of a side view of the interdental brush 1 that takes the second usage pattern. The second usage form is a form suitable mainly for cleaning between premolar teeth. In the second usage pattern, the handle portion 10 is bent at the first bending planned portion 41 so that the brush portion 100 falls down.

  FIG. 12 is an example of a side view of the interdental brush 1 that takes the third usage pattern. The third usage pattern is mainly suitable for cleaning between molar teeth. In the third usage pattern, the handle portion 10 is bent at the second scheduled bending portion 42 so that the brush portion 100 falls down.

  FIG. 13 is an example of a side view of the interdental brush 1 taking the fourth usage pattern. The fourth usage pattern is a form suitable mainly for cleaning between molar teeth. In the fourth usage pattern, the handle portion 10 is bent at the respective bending planned portions 41 and 42 so that the brush portion 100 falls down.

  As shown in FIG. 3, the handle portion 10 further includes an opening 50 and a partition wall 60. The opening 50 and the partition wall 60 are provided in the neck portion 20. The opening 50 is a portion including a hole formed in the handle portion 10 and a resin portion of the handle portion 10 that forms the hole. In one example, the opening 50 includes a first opening 51 and a second opening 52 (see FIG. 2). The first opening 51 is open in the first front surface 10A. The second opening 52 is open in the second front surface 10B. The partition wall 60 partitions the first opening 51 and the second opening 52.

  Since the handle portion 10 includes the opening 50, it can be easily confirmed that the handle portion 10 and the core member 110 are appropriately joined. Since the opening part 50 includes the first opening part 51 and the second opening part 52, the joining state of the handle part 10 and the core member 110 can be obtained from either the first front face 10A side or the second front face 10B side of the handle part 10. Easy to confirm. Since the opening 50 is provided in the neck 20, it is difficult for the user's finger to get caught in the opening 50 when the interdental brush 1 is used.

  The handle portion 10 is made of a resin material. For this reason, the whole handle | steering-wheel part 10 can be integrally molded, and the interdental brush 1 can be manufactured efficiently. It is preferable that the type of resin material constituting the handle portion 10 and the physical property values thereof are determined based on, for example, the relationship between the strength of the handle portion 10 against fatigue and the ease of bending the handle portion 10. The physical properties of the resin material that affect these factors include at least density, melting point, and elastic modulus. The strength of the handle portion 10 against fatigue is preferably determined so that fatigue does not occur during the general period of use of the interdental brush 1.

  An example of a preferable resin material is a crystalline resin material. An example of a preferred crystalline resin material is a polyolefin resin. An example of a preferred polyolefin resin is a polyethylene resin or a polypropylene resin (PP). An example of a preferable polyethylene resin is a linear low density polyethylene resin (LLDPE), a high density polyethylene resin (HDPE), or a branched low density polyethylene resin (LDPE). Preferred physical property values when the handle portion 10 is made of a polyolefin resin are shown below.

An example of a preferable upper limit of the density is 930 kg / m ³ . An example of a more preferable upper limit of the density is 928 kg / m ³ . An example of a preferable lower limit of the density is 920 kg / m ³ . An example of a more preferable lower limit of the density is 923 kg / m ³ . An example of a preferred range for density is 920-930 kg / m ³ . An example of a more preferred range for density is 923-928 kg / m ³ . An example of a preferred density is 925 kg / m ³ .

  An example of a preferable upper limit of the melting point is 126 ° C. An example of a more preferable upper limit of the melting point is 124 ° C. An example of a lower limit of the preferable melting point is 120 ° C. An example of a more preferable lower limit of the melting point is 121 ° C. An example of a preferable range regarding the melting point is 120 to 126 ° C. An example of a more preferable range regarding the melting point is 121 to 124 ° C. An example of a preferable melting point is 123 ° C.

  An example of a preferable upper limit of the elastic modulus is 300 MPa. An example of a more preferable upper limit of the elastic modulus is 230 MPa. An example of a preferable lower limit of the elastic modulus is 200 MPa. An example of a more preferable lower limit of the elastic modulus is 210 MPa. An example of a preferable range regarding the elastic modulus is 200 to 300 MPa. An example of a more preferable range regarding the elastic modulus is 210 to 230 MPa. An example of a preferable elastic modulus is 230 MPa.

Details of the neck portion 20 will be described with reference to FIGS. 3 and 4.
The neck portion 20 includes a base portion 21, an intermediate portion 22, and a distal end portion 23. The base portion 21 is a portion connected to the grip portion 30. The opening 50 is provided in the base 21. The shape of the intermediate part 22 is a flat shape. The first bent scheduled portion 41 is provided in the base portion 21 and the intermediate portion 22. The distal end portion 23 is a portion including the first end portion 10 </ b> C of the handle portion 10.

  As shown in FIGS. 3 and 4, the width and thickness of the neck portion 20 are different for each portion of the neck portion 20. The width of the neck portion 20 is the dimension of the neck portion 20 in the width direction of the interdental brush 1. The thickness of the neck portion 20 is a dimension of the neck portion 20 in the thickness direction of the interdental brush 1. The width LA and the thickness LB of the base portion 21 become narrower from the grip portion 30 side toward the intermediate portion 22 side. In the cross section of the neck portion 20 orthogonal to the central axis C of the interdental brush 1, the width LA is larger than the thickness LB. The width LC and the thickness LD of the intermediate part 22 are constant. In the cross section of the neck portion 20 orthogonal to the central axis C of the interdental brush 1, the width LC is larger than the thickness LD.

  As shown in FIG. 5, the first bent portion 41 includes one or a plurality of first grooves 41 </ b> A. In the illustrated example, the first bending planned portion 41 includes eight first grooves 41A. 41 A of 1st groove | channels are formed so that the neck part 20 can be bent in the direction in which the protrusion part 120 of the brush part 100 falls down. Each first groove 41A is provided on each of the first front surface 10A and the second front surface 10B. The first grooves 41 </ b> A are arranged in the axial direction of the interdental brush 1. Each first groove 41 </ b> A is provided in substantially the entire neck portion 20 in the width direction of the interdental brush 1. Since the first bent portion 41 includes at least one first groove 41A, the first bent portion 41 can be easily bent. In the following description, in order to distinguish each first groove 41A, the number of the first groove 41A is determined in order from the first groove 41A formed closest to the grip portion 30.

  The width XA and the depth HA (see FIG. 6) of the first groove 41A are preferably determined from, for example, the relationship between the ease of bending of the first bending planned portion 41 and the strength of the neck portion 20 against bending. . The width XA of the first groove 41A is the dimension of the first groove 41A in the axial direction of the interdental brush 1. The depth HA of the first groove 41A is a dimension of the first groove 41A in the thickness direction of the interdental brush 1, and is, for example, a cross section of the handle portion 10 orthogonal to the center plane D of the interdental brush 1 (see FIG. 6). ) As specified above.

  The width XA1 of the first first groove 41A is the largest among the widths XA of the first grooves 41A. The width XA2 of the second first groove 41A is the second largest among the widths XA of the first grooves 41A. The width XA3 of the third first groove 41A is the third largest among the widths XA of the first grooves 41A. The widths XA4 of the fourth to eighth eighth grooves 41A are equal to each other, and are the narrowest among the widths XA of the first grooves 41A.

  An example of a preferable upper limit of the width XA is 1.2 mm. An example of a more preferable upper limit of the width XA is 1.0 mm. An example of a preferable lower limit of the width XA is 0.3 mm. An example of a more preferable lower limit of the width XA is 0.4 mm. An example of a preferable range for the width XA is 0.3 to 1.2 mm. An example of a more preferable range for the width XA is 0.4 to 1.0 mm. An example of a preferable width XA1 is 1.01 mm. An example of a preferable width XA2 is 0.8 mm. An example of a preferable width XA3 is 0.6 mm. An example of a preferred width XA4 is 0.4 mm.

  The depth HA of each first groove 41A is the same. An example of a preferable upper limit of the depth HA is 0.7 mm. An example of a more preferable upper limit of the depth HA is 0.6 mm. An example of a preferable lower limit of the depth HA is 0.05 mm. An example of a more preferable lower limit of the depth HA is 0.1 mm. An example of a preferable range for the depth HA is 0.05 to 0.7 mm. An example of a more preferable range for the depth HA is 0.1 to 0.6 mm. An example of a preferred depth HA is 0.1 mm.

The detail of the grip part 30 is demonstrated with reference to FIG. 3 and FIG.
The grip part 30 includes an upper part 31, an intermediate part 32, and a lower part 33. The shape of the grip part 30 is a flat shape. The upper part 31 is a part connected to the base part 21 of the neck part 20. The lower portion 33 is a portion including the second end portion 10D of the handle portion 10. The intermediate part 32 is a part between the upper part 31 and the lower part 33. The second bending scheduled portion 42 is provided in the intermediate portion 32. The grip part 30 is bundled so that the intermediate part 32 is thinner than the upper part 31 and the lower part 33 in the front view of the interdental brush 1.

  As shown in FIG. 3, the second scheduled bending portion 42 includes one or a plurality of second grooves 42 </ b> A. In the illustrated example, the second bending scheduled portion 42 includes six second grooves 42A. 42 A of 2nd grooves are formed so that the grip part 30 can be bent in the direction in which the protrusion part 120 of the brush part 100 falls down. The second groove 42A is provided on each of the first front surface 10A and the second front surface 10B. Each second groove 42 </ b> A is arranged in the axial direction of the interdental brush 1. Each of the second grooves 42 </ b> A is provided so as to go around the grip portion 30 around the central axis C of the interdental brush 1. Since the second bending planned part 42 includes at least one second groove 42A, the second bending planned part 42 can be easily bent.

  The width XB and the depth HB (see FIG. 6) of the second groove 42A are preferably determined from, for example, the relationship between the ease of bending of the second scheduled bending portion 42 and the strength of the grip portion 30 against bending. . The width XB of the second groove 42A is the dimension of the second groove 42A in the axial direction of the interdental brush 1. The depth HB of the second groove 42A is the dimension of the second groove 42A in the thickness direction of the interdental brush 1, and is, for example, a cross section of the handle portion 10 orthogonal to the center plane D of the interdental brush 1 (see FIG. 6). ) As specified above.

  The width XB of each second groove 42A is the same. An example of a preferable upper limit of the width XB is 0.7 mm. A more preferable example of the upper limit of the width XB is 0.6 mm. An example of a preferable lower limit of the width XB is 0.3 mm. An example of a more preferable lower limit of the width XB is 0.4 mm. An example of a preferable range for the width XB is 0.3 to 0.7 mm. An example of a more preferable range regarding the width XB is 0.4 to 0.6 mm. An example of a preferable width XB is 0.5 mm.

  The depth HB of each second groove 42A is the same. An example of the upper limit of the preferable depth HB is 1.2 mm. An example of a more preferable upper limit of the depth HB is 1.0 mm. An example of a preferable lower limit of the depth HB is 0.2 mm. An example of a more preferable lower limit of the depth HB is 0.3 mm. An example of a preferable range for the depth HB is 0.2 to 1.2 mm. An example of a more preferable range for the depth HB is 0.3 to 1.0 mm. An example of a preferred depth HB is 0.5 mm.

Details of the brush unit 100 will be described with reference to FIG. 6.
The core material 110 is composed of a wire. Examples of materials that make up the wire are stainless steel, ferritic stainless steel, austenitic stainless steel, austenitic ferritic stainless steel, martensitic stainless steel, folding hardened stainless steel, nickel-based alloy, cobalt-based alloy, Or it is a titanium-nickel alloy.

  The core material 110 is twisted so that the filament bundle 200 can be held. In one example, the brush unit 100 is configured as follows. First, one wire that is a material of the core member 110 is bent, and a portion bent by the wire (hereinafter, “bent portion 110P of the core member 110”) is formed. Thereby, the wire is divided into one part (hereinafter, “first folded part 110A of the core material 110”) and the other part (hereinafter, “second folded part 110B of the core material 110”) with respect to the bent part 110P. The

  Next, the first folded portion 110A and the second folded portion 110B of the core member 110 are overlaid so as to be parallel to each other. Next, the filament bundle 200 is inserted between the first folded portion 110A and the second folded portion 110B so as to be sandwiched between the overlapped first folded portion 110A and second folded portion 110B. Next, the first folded portion 110A and the second folded portion 110B are twisted together so that the filament bundle 200 is strongly held by the first folded portion 110A and the second folded portion 110B.

  After the first folded portion 110A and the second folded portion 110B are twisted, the filament bundle 200 is cut into, for example, a conical shape, whereby the brush portion 100 is configured. The twisted first folded portion 110A and second folded portion 110B constitute a single wire. 110 C of front-end | tip parts of the core material 110 contain the bending part 110P. The covering end 110D, which is the end of the core member 110 opposite to the tip 110C, includes the tip of the first folded part 110A and the tip of the second folded part 110B. The thickness of the core material 110 is different in the direction along the central axis of the core material 110. In one example, the maximum thickness of the core material 110 represents the thickness of the core material 110. The maximum thickness of the core material 110 is approximately twice the diameter of the wire.

  The core material 110 includes a protruding portion 120 and a covering portion 130. The protruding part 120 includes a holding part 121 and a non-holding part 122. The holding part 121 includes a bent part 110P of the core member 110, and is a part in which the filament bundle 200 is planted. The non-holding part 122 is a part between the holding part 121 and the tip part 23 of the neck part 20, and is a part where the filament bundle 200 is not implanted.

  The thickness of the protrusion 120 is preferably determined from the relationship with the strength of the protrusion 120 against bending, for example. The thickness of the protrusion 120 is the same as the thickness of the core 110, for example. An example of the upper limit of the thickness of the preferable protrusion 120 is 0.7 mm. An example of the upper limit of the thickness of the more preferable protrusion part 120 is 0.6 mm. An example of the minimum of the thickness of the preferable protrusion part 120 is 0.3 mm. An example of a more preferable lower limit of the thickness of the protrusion 120 is 0.4 mm. An example of the preferable range regarding the thickness of the protrusion part 120 is 0.3-0.7 mm. An example of the more preferable range regarding the thickness of the protrusion part 120 is 0.4-0.6 mm. An example of the thickness of the preferable protrusion 120 is 0.4 mm.

  The covering portion 130 is a portion covered with the handle portion 10 and includes a first portion 131 and a second portion 132. The first portion 131 is a portion that is not subjected to plastic working. The second portion 132 is a portion subjected to plastic working. An example of plastic working performed on the second portion 132 is press working. The second portion 132 is formed by pressing a part of the core material 110 in which the first folded portion 110A and the second folded portion 110B are twisted. The shape of the second portion 132 is a flat, substantially rectangular shape. The shape of the second portion 132 can be arbitrarily changed. Other examples of the shape of the second portion 132 are a flat approximately square shape, a flat approximately circular shape, a flat approximately elliptical shape, or a flat approximately triangular shape. The second portion 132 is provided at an arbitrary position of the covering portion 130 of the core material 110. In a preferred example, the second portion 132 is provided in a range including the covering end portion 110 </ b> D of the core material 110. A part of the covering portion 130 (hereinafter, “visible portion 133”) is visible through the opening 50. In one example, the visible portion 133 is included in the first portion 131.

  The thickness MA of the first portion 131 is, for example, the relationship between the ease of bending of the first bent portion 41, the retainability of the shape of the neck portion 20 in the bent state, and the strength of the neck portion 20 against fatigue. It is preferable to be determined from In the illustrated example, the thickness of the first portion 131 is the same as the thickness of the core member 110.

  An example of a preferable upper limit of the thickness of the first portion 131 is 0.7 mm. A more preferable example of the upper limit of the thickness of the first portion 131 is 0.6 mm. An example of a preferable lower limit of the thickness of the first portion 131 is 0.3 mm. An example of a more preferable lower limit of the thickness of the first portion 131 is 0.4 mm. An example of a preferable range regarding the thickness MA of the first portion 131 is 0.3 to 0.7 mm. An example of a more preferable range regarding the thickness MA of the first portion 131 is 0.4 to 0.6 mm. An example of a preferable thickness MA of the first portion 131 is 0.4 mm. The thickness MA of the first portion 131 is preferably larger than the thickness of the partition wall 60.

  The ease of bending of the first scheduled bending portion 41 and the retainability of the shape of the neck portion 20 are related not only to the thickness MA itself of the first portion 131 but also to the core material occupation ratio PX. The core material occupation ratio PX is a ratio of the thickness MA of the first portion 131 to the thickness of the thinnest portion in the neck portion 20 (hereinafter, “minimum dimension PM”). In one example, the minimum dimension PM is defined on the cross section (see FIG. 6) of the handle portion 10 orthogonal to the center plane D of the interdental brush 1, and the bottom surface of the first groove 41A formed on the first front surface 10A 2 Distance from the bottom surface of the first groove 41A formed on the front surface 10B. The formula for obtaining the core material occupation ratio PX is “PX = MA / PM × 100 (%)”.

  An example of a preferable upper limit of the core material occupation ratio PX is 45%. A more preferable example of the upper limit of the core material occupation ratio PX is 40%. An example of a preferable lower limit of the core material occupation ratio PX is 15%. An example of a more preferable lower limit of the core material occupation ratio PX is 20%. An example of a preferable range for the core material occupation ratio PX is 15 to 45%. An example of a more preferable range regarding the core material occupation ratio PX is 20 to 40%. An example of a preferable core material occupation ratio PX is 20%. When the core material occupation ratio PX is included in the range of 20% or more, the state where the neck portion 20 is bent is easily maintained. When the core material occupation ratio PX is included in the range of 40% or less, the first bending planned portion 41 is easily bent.

  The degree of deformation of the covering portion 130 by plastic working can be defined by at least one of the first deformation rate PA and the second deformation rate PB, for example. The first deformation ratio PA is a ratio of the maximum width MB (see FIG. 9) of the second portion 132 to the thickness MA of the first portion 131. The maximum width MB of the second portion 132 is a dimension of the second portion 132 in the width direction of the interdental brush 1. The formula for obtaining the first deformation ratio PA is “PA = MB / MA × 100 (%)”. The second deformation rate PB is a ratio of the thickness MA of the first portion 131 to the thickness MC (see FIG. 8) of the second portion 132. The thickness MC of the second portion 132 is a dimension of the second portion 132 in the thickness direction of the interdental brush 1. The formula for obtaining the second deformation rate PB is “PB = MA / MC × 100 (%)”.

  The first deformation rate PA is preferably determined from, for example, the relationship between the bonding strength between the handle portion 10 and the covering portion 130 against twisting and the strength of the second portion 132 of the covering portion 130. An example of a preferable upper limit of the first deformation rate PA is 150%. A more preferable example of the upper limit of the first deformation rate PA is 145%. An example of a preferable lower limit of the first deformation rate PA is 130%. An example of a more preferable lower limit of the first deformation rate PA is 135%. An example of a preferable range for the first deformation ratio PA is 130% to 150%. An example of a more preferable range regarding the first deformation rate PA is 135 to 145%. An example of a preferable first deformation rate PA is 140%.

  When the first deformation rate PA is included in the range of 130% or more, when the force for twisting the handle portion 10 and the protruding portion 120 is applied to the interdental brush 1, the connection between the handle portion 10 and the covering portion 130 is difficult to come off. . When the first deformation rate PA is included in the range of 150% or less, high strength is ensured for the second portion 132. Further, when the interdental brush 1 is manufactured by insert molding, the position of the brush portion 100 with respect to the mold is not easily displaced from the specified position.

  The second deformation rate PB is preferably determined from, for example, the relationship between the bonding strength between the handle portion 10 and the covering portion 130 and the strength of the second portion 132 against twisting. An example of a preferable upper limit of the second deformation rate PB is 260%. An example of a more preferable upper limit of the second deformation rate PB is 250%. An example of a lower limit of the preferred second deformation rate PB is 200%. An example of a more preferable lower limit of the second deformation rate PB is 210%. An example of a preferable range for the second deformation rate PB is 200 to 260%. An example of a more preferable range regarding the second deformation rate PB is 210 to 250%. An example of a preferable second deformation rate PB is 240%.

  When the second deformation rate PB is included in the range of 200% or more, when a force for twisting the handle portion 10 and the protruding portion 120 is applied, the connection between the handle portion 10 and the covering portion 130 is difficult to come off. When the second deformation rate PB is included in the range of 260% or less, high strength is secured for the second portion 132. Further, when the interdental brush 1 is manufactured by insert molding, the position of the brush portion 100 with respect to the mold is not easily displaced from the specified position.

  Factors other than the first deformation rate PA and the second deformation rate PB are also related to the bonding strength between the handle portion 10 and the covering portion 130 against twisting. One example is the separation ratio PC and the coverage ratio PD. The separation rate PC and the coverage rate PD individually affect the bonding strength, and also affect the bonding strength independently of the first deformation rate PA and the second deformation rate PB.

  The separation ratio PC is a ratio of the separation distance HY of the second portion 132 to the length HX of the covering portion 130 shown in FIGS. 6 and 7. The length HX of the covering portion 130 is a dimension of the covering portion 130 in the axial direction of the interdental brush 1. The separation distance HY of the second portion 132 is the distance between the covering end portion 110D of the core member 110 and the center point 132A of the second portion 132. The formula for obtaining the separation rate PC is “PC = HY / HX × 100 (%)”.

  An example of a preferable range for the separation rate PC is 55% or less. An example of a more preferable range regarding the separation rate PC is 30% or less. An example of a preferable separation ratio PC is 7%. When the separation ratio PC is included in the range of 55% or less, when the force for twisting the handle portion 10 and the protruding portion 120 is applied to the interdental brush 1, the connection between the handle portion 10 and the covering portion 130 is unlikely to come off.

  The coverage PD is a ratio of the length HX of the covering portion 130 to the length ZA of the core material 110. The length ZA of the core material 110 is the overall dimension of the core material 110 in the axial direction of the interdental brush 1. The length HX of the covering portion 130 is the overall dimension of the covering portion 130 in the axial direction of the interdental brush 1. The formula for determining the coverage PD is “PD = HX / ZA × 100 (%)”.

  An example of the preferable range regarding the coverage PD is 40% or more. An example of a more preferable range regarding the coverage PD is 55% or more. An example of a preferable coverage PD is 60%. When the coverage PD is included in the range of 40% or more, when the force for twisting the handle portion 10 and the protruding portion 120 is applied to the interdental brush 1, the connection between the handle portion 10 and the covering portion 130 is difficult to come off.

  As an example of a factor related to the operability of the interdental brush 1, the protrusion rate PE can be mentioned. The protrusion rate PE is a ratio of the length NA of the neck portion 20 to the length SA of the protrusion 120. The length SA of the protrusion 120 is the dimension of the protrusion 120 in the axial direction of the interdental brush 1. The length NA of the neck portion 20 is a dimension of the neck portion 20 in the axial direction of the interdental brush 1. The formula for obtaining the protrusion rate PE is “PE = NA / SA × 100 (%)”. The protrusion rate PE is preferably determined from the relationship between the insertion property of the cleaning unit 140 between the teeth and the distance between the cleaning unit 140 and the grip unit 30 in the axial direction of the interdental brush 1.

  An example of the upper limit of the preferable protrusion rate PE is 150%. An example of a more preferable upper limit of the protrusion rate PE is 140%. An example of a preferable lower limit of the protrusion ratio PE is 30%. An example of a more preferable lower limit of the protrusion ratio PE is 40%. An example of the preferable range regarding the protrusion rate PE is 30 to 150%. An example of a more preferable range regarding the protrusion rate PE is 40 to 140%. An example of a preferable protrusion rate PE is 125%.

  When the protrusion rate PE is included in the range of 30% or more, the distance between the grip part 30 and the cleaning part 140 is increased in the axial direction of the interdental brush 1, so that plaque, food residue, and the like attached to the cleaning part 140 are present. It is difficult to adhere to the user's hand. In addition, since the distance between the opening 50 and the cleaning unit 140 is increased, it is difficult for plaque or the like attached to the cleaning unit 140 to enter the opening 50. When the protrusion rate PE is included in the range of 170% or less, the cleaning unit 140 is easily inserted between the teeth.

The details of the opening 50 and the partition wall 60 will be described with reference to FIG.
The opening 50 includes a hole opened so that the visible portion 133 of the covering portion 130 can be visually recognized from the outside of the handle portion 10. For this reason, it can be visually confirmed through the opening part 50 whether the partition wall 60 and the coating | coated part 130 are joined appropriately. As an example of a state in which the partition wall 60 and the covering portion 130 are not properly joined, the state in which the core material 110 cannot be visually recognized through the opening 50 and the core material 110 visually recognized through the opening 50 are teeth. The state which has deviated remarkably with respect to the central axis C of the intermediate brush 1 is mentioned. When such a state is confirmed, the corresponding interdental brush 1 can be excluded from the object of shipment. The first opening 51 includes a hole opened at the base 21 of the neck 20 in the first front surface 10A. The 2nd opening part 52 (refer FIG. 2) contains the hole opened in the base 21 of the neck part 20 of the 2nd front 10B. The opening area of the hole included in each of the openings 51 and 52 becomes narrower from the opening of the hole toward the partition wall 60.

  The minimum opening area in the opening 50 is preferably determined from the relationship with the visibility of the covering 130, for example. In one example, the portion of the first opening 51 that is closest to the partition wall 60 (hereinafter “the bottom 51A of the first opening 51”) has the smallest opening area. The shape of the bottom 51A of the first opening 51 is rectangular. The minimum opening area is determined by the dimension YA of the bottom 51A in the axial direction of the interdental brush 1 and the dimension YB of the bottom 51A in the width direction of the interdental brush 1.

An example of a preferable upper limit of the minimum opening area is 2.0 mm ² . An example of a more preferable upper limit of the minimum opening area is 1.8 mm ² . An example of a preferable lower limit of the minimum opening area is 1.0 mm ² . An example of a lower limit of a more preferable minimum opening area is 1.2 mm ² . An example of a preferable range for the minimum opening area is 1.0 to 1.2 mm ² . An example of a more preferable range for the minimum opening area is 1.2 to 1.8 mm ² . An example of a preferred minimum opening area is 1.8 mm ² . Note that the minimum opening area in the second opening 52 is determined in the same manner as in the first opening 51.

  The partition wall 60 is joined to the covering portion 130. For this reason, the handle | steering-wheel part 10 and the coating | coated part 130 are joined more strongly. The thickness of the partition wall 60 is preferably determined based on, for example, the visibility of the covering portion 130 through the opening 50 and the bonding strength between the handle portion 10 and the covering portion 130 with respect to twisting. The thickness of the partition wall 60 is the dimension of the partition wall 60 in the thickness direction of the interdental brush 1.

  An example of the upper limit of the thickness of the preferable partition wall 60 is 0.7 mm. A more preferable example of the upper limit of the thickness of the partition wall 60 is 0.6 mm. An example of the minimum of the thickness of the preferable division wall 60 is 0.3 mm. An example of a more preferable lower limit of the thickness of the partition wall 60 is 0.4 mm. An example of the preferable range regarding the thickness of the partition wall 60 is 0.3-0.7 mm. An example of a more preferable range regarding the thickness of the partition wall 60 is 0.4 to 0.6 mm. An example of the thickness of the preferable partition wall 60 is 0.4 mm. When the thickness of the partition wall 60 is included in the range of 0.3 mm or more, the handle portion 10 and the covering portion 130 are more strongly joined. When the thickness of the partition wall 60 is included in the range of 0.7 mm or less, the visibility of the covering portion 130 through the opening 50 is enhanced.

With reference to FIGS. 11-13, the 2nd-4th usage pattern of the interdental brush 1 is demonstrated.
In the second usage pattern shown in FIG. 11, the first bending planned portion 41 is bent. For this reason, the angle (hereinafter referred to as “first angle θA”) formed by the central axis C of the handle portion 10 and the central axis CA of the portion of the neck portion 20 closer to the distal end portion 23 than the first bending portion 41 is. , Greater than 0 degrees. For example, the first angle θA is preferably included in a range in which the shape of the handle portion 10 becomes a shape in which the cleaning portion 140 can be easily inserted and removed between the molar teeth. An example of a preferable range for the first angle θA is greater than 0 degree and 90 ° or less. An example of a more preferable range for the first angle θA is 40 to 60 °. A preferred example for the first angle θA is 40 °.

  In the third usage pattern shown in FIG. 12, the second scheduled bending portion 42 is bent. For this reason, the angle (hereinafter referred to as “second angle θB”) formed by the central axis C of the handle portion 10 and the central axis CB of the portion of the grip portion 30 closer to the neck portion 20 than the second bending planned portion 42 is. , Greater than 0 degrees. For example, it is preferable that the second angle θB is included in a range in which the shape of the handle portion 10 is a shape with high grip and operability. An example of a preferable range for the second angle θB is greater than 0 degree and equal to or less than 40 °. An example of a more preferable range for the second angle θB is 25 to 35 °. A preferred example for the second angle θB is 30 °.

  In the fourth usage pattern shown in FIG. 13, the respective bending planned portions 41 and 42 are bent. For this reason, the angle formed by the central axis C of the handle portion 10 and the central axis CC of the portion of the neck portion 20 closer to the distal end portion 23 than the first bending planned portion 41 (hereinafter, “third angle θC”) is , Greater than 0 degrees. For example, the third angle θC is preferably included in a range in which the shape of the handle portion 10 becomes a shape that allows the cleaning portion 140 to be easily inserted and removed during cleaning between molar teeth. An example of a preferable range for the third angle θC is greater than 0 degree and equal to or less than 80 °. An example of a more preferable range for the third angle θC is 50 to 60 °. A preferred example of the third angle θC is 55 °.

  The angle (hereinafter referred to as “fourth angle θD”) formed by the central axis C of the handle portion 10 and the central axis CD of the portion of the grip portion 30 closer to the neck portion 20 than the second bent portion 42 is 0 degree. Bigger than. For example, it is preferable that the fourth angle θD is included in a range in which the shape of the handle portion 10 is a shape with high grip and operability. An example of a preferred range for the fourth angle θD is greater than 0 degrees and 30 degrees or less. An example of a more preferable range for the fourth angle θD is 10 to 20 °. A preferable example of the fourth angle θD is 15 °.

With reference to FIG. 14 and FIG. 15, the manufacturing method of the interdental brush 1 is demonstrated.
In one example, the interdental brush 1 is manufactured by insert molding. In the first step, the brush unit 100 is manufactured. In the second step, as shown in FIG. 14, the brush unit 100 is disposed at a specified position in the mold 300. The mold 300 includes a holding mold 310 and a mold 340. The holding mold 310 is a mold for holding the brush unit 100. The molding die 340 is a mold for molding the handle portion 10.

  The holding mold 310 includes a fixed holding mold 320 and a movable holding mold 330. The fixed holding mold 320 includes a first holding part 321 and a first housing part 322. The first holding part 321 includes a groove in which the non-holding part 122 of the core member 110 can be arranged. The 1st accommodating part 322 contains the recessed part which can arrange | position the half of the brush part 100 with respect to the center surface D (refer FIG. 4) of the interdental brush 1. FIG. The movable holding mold 330 includes a second holding part 331 and a second housing part 332. The second holding part 331 includes a groove in which the non-holding part 122 of the core material 110 can be arranged. The 2nd accommodating part 332 contains the recessed part which can arrange | position the half of the brush part 100 with respect to the center surface D (refer FIG. 4) of the interdental brush 1. FIG.

  Mold 340 includes a fixed mold 350 and a movable mold 360. The fixed mold 350 includes a first molding part 351, a first gate part 352, a first seal part 353, and a first convex part 354. The first molding part 351 is for molding one of the part on the first front surface 10A side and the part on the second front surface 10B side of the handle part 10 divided by the center surface D (see FIG. 4) of the interdental brush 1. Including a recess. The first gate portion 352 includes a groove that constitutes a part of the gate 342 of the mold 340. The first seal part 353 constitutes a part of the seal part 343 of the mold 340. The first convex portion 354 is a convex portion for molding one of the first opening 51 and the second opening 52 in the handle portion 10.

  The movable mold 360 includes a second molding part 361, a second gate part 362, a second seal part 363, and a second convex part 364. The second forming portion 361 is for forming the other of the portion on the first front surface 10A side and the portion on the second front surface 10B side of the handle portion 10 divided by the center surface D (see FIG. 4) of the interdental brush 1. Including a recess. The second gate portion 362 includes a groove that constitutes a part of the gate 342 of the mold 340. The second seal portion 363 constitutes a part of the seal portion 343 of the mold 340. The second convex portion 364 is a convex portion for forming the other of the first opening 51 and the second opening 52 in the handle portion 10.

  In the second step, specifically, the brush unit 100 is arranged at a specified position in the holding mold 310 as follows. First, the brush unit 100 is placed in the opened fixed holding mold 320. At this time, the non-holding portion 122 of the core material 110 is disposed in the first holding portion 321. Next, the movable holding mold 330 is matched to the fixed holding mold 320 so that the closed holding mold 310 is configured. When the closed holding mold 310 is configured, the first holding portion 321 and the second holding portion 331 sandwich the non-holding portion 122 of the core material 110. For this reason, the position of the brush part 100 with respect to the holding die 310 is determined.

  Next, the holding mold 310 is disposed at a position in contact with the fixed mold 350 so that the covering section 130 of the brush unit 100 held by the holding mold 310 is disposed on the fixed mold 350. At this time, the visible portion 133 of the covering portion 130 is disposed on the first convex portion 354. Next, the movable mold 360 is aligned with the fixed mold 350 so that a closed mold 340 is constructed. The closed mold 340 includes a molding space 341, a gate 342, and a seal portion 343. The molding space 341 includes a first molding part 351 and a second molding part 361. The gate 342 includes a first gate portion 352 and a second gate portion 362 so that molten resin can be supplied to the molding space 341. The seal portion 343 includes a first seal portion 353 and a second seal portion 363 so that the resin supplied to the molding space 341 does not flow into the holding mold 310.

  When the closed mold 340 is configured, the second convex portion 364 is disposed on the visible portion 133 of the covering portion 130, and the first convex portion 354 and the second convex portion 364 are spaced apart from each other by a predetermined distance (hereinafter, “ Opposite portions TA ") are opposed to each other. The convex portion interval TA is a distance between the end surface 354A of the first convex portion 354 and the end surface 364A of the second convex portion 364 in the closed mold 340. The end surface 354A of the first convex portion 354 and the end surface 364A of the second convex portion 364 are regions facing the visible portion 133 in the direction orthogonal to the end surfaces 354A and 364A (hereinafter referred to as “first region”), and in the same direction. 2 includes a region (hereinafter referred to as “second region”) that does not face the visible portion 133. The partition wall 60 (see FIG. 5) is formed of resin supplied between the end faces 354A and 364A.

  The state (hereinafter referred to as “opposing state”) of the convex portions 354 and 364 with respect to the visible portion 133 is classified into first to third opposing states according to the convex portion interval TA. Any one of the first to third opposing states can be selected by setting the heights of the convex portions 354 and 364. The first facing state is a state in which the convex portion interval TA is substantially equal to the thickness of the visible portion 133 and the end faces 354A, 364A and the visible portion 133 are in contact with each other without being crimped. The second facing state is a state in which the convex portion interval TA is substantially equal to the thickness of the visible portion 133 and the end surfaces 354A and 364A and the visible portion 133 are pressure-bonded. The third facing state is a state in which the convex portion interval TA is wider than the thickness of the visible portion 133 and the end faces 354A, 364A and the visible portion 133 are not in contact with each other.

  In the example shown in FIG. 14, the facing state of the convex portions 354 and 364 is the second facing state. Each of the convex portions 354 and 364 holds the visible portion 133 of the covering portion 130 that is a portion closer to the second portion 132 than the center of the covering portion 130 in the axial direction of the interdental brush 1. As described above, when the portions closer to the gate 342 in the covering portion 130 are held by the convex portions 354 and 364, the covering portion 130 becomes more difficult to bend when the resin is injected into the molding space 341.

  In the third step shown in FIG. 15, the molten resin is injected into the molding space 341 (see FIG. 14) through the gate 342. The resin supplied around the convex portions 354 and 364 forms the opening 50 (see FIG. 5) of the handle portion 10. When the first region of each of the end surfaces 354A and 364A is in contact with the visible portion 133, the resin is between the portion of the visible portion 133 that is in contact with the first region and the first region of each of the end surfaces 354A and 364A. Is not supplied, and the resin is supplied between the second region of the end surface 354A and the second region of the end surface 364A. When the first regions of the end surfaces 354A and 364A are not in contact with the visible portion 133, between the visible portion 133 and the first regions of the end surfaces 354A and 364A, and between the second region and the end surface 364A of the end surface 354A. The resin is supplied between the second region. The resin supplied between the end faces 354A and 364A forms a partition wall 60 (see FIG. 5). The partition wall 60 (see FIG. 5) formed in the example shown in FIG. 15 does not cover the portion of the visible portion 133 that comes into contact with the first region. In the fourth step, the handle portion 10 is cooled until the injected resin is cured. In the fifth step, the holding mold 310 and the mold 340 are opened, the interdental brush 1 is taken out from the mold 300, and the resin portion corresponding to the gate 342 is cut from the handle portion 10.

The detail of the opposing state of each convex part 354,364 is demonstrated.
In the first facing state, the first regions of the end surfaces 354A and 364A are in contact with the visible portion 133 so as not to substantially deform the visible portion 133, and the second regions of the end surfaces 354A and 364A are interposed via a gap. Opposite. For this reason, each convex part 354 and 364 hold | maintain the coating | coated part 130 with the frictional force between a 1st area | region and the to-be-viewed part 133. FIG. In the second facing state, the first regions of the end surfaces 354A and 364A are pressure-bonded to the visible portion 133, and the second regions of the end surfaces 354A and 364A are opposed to each other via a gap. For this reason, each convex part 354, 364 hold | maintains the coating | coated part 130 with a stronger frictional force than a 1st opposing state.

  According to the first facing state and the second facing state, the covering portion 130 which is the portion on the gate 342 side in the brush portion 100 is held by the respective convex portions 354 and 364, so that the resin is injected into the molding space 341. The covering portion 130 is difficult to bend. For this reason, the moldability of the handle part 10 is improved. According to the second facing state, since the frictional force between the convex portions 354 and 364 and the visible portion 133 is large, the covering portion 130 is more difficult to bend, and the formability of the handle portion 10 is further improved. Further, when the first opposing state or the second opposing state is formed in the mold 340, the non-holding portion 122 is held by the holding portions 321, 331, and the visible portion 133 is held by the convex portions 354, 364. Therefore, the position and posture of the brush unit 100 with respect to the mold 300 are stabilized when the resin is injected into the molding space 341. This point also contributes to improving the formability of the handle portion 10. Further, according to the first facing state and the second facing state, the partition wall 60 (see FIG. 5) is not covered with the partition wall 60 (see FIG. 5) because the portion of the visible portion 133 that contacts the first region of each of the end surfaces 354A and 364A The visibility of the visual recognition part 133 is further enhanced.

  In the third facing state, the first regions of the end surfaces 354A and 364A are opposed to the visible portion 133 without being in contact with the visible portion 133, and the second regions of the end surfaces 354A and 364A are opposed via a gap. Yes. According to the third facing state, the range in which the covering portion 130 bends is limited by the end faces 354A and 364A, so that the covering portion 130 is prevented from being greatly bent when the resin is injected into the molding space 341. For this reason, the moldability of the handle part 10 is improved. The range in which the covering portion 130 bends when the resin is injected becomes narrower as the convex portion interval TA is narrower. When the handle portion 10 is molded in the third facing state, the entire visible portion 133 is covered with the partition wall 60 (see FIG. 5). Even in this case, the visibility of the visible portion 133 can be increased by reducing the thickness of the partition wall 60. When the resin material forming the partition wall 60 is a resin material having a high transmittance such as a transparent material and a translucent material, a part of the visible portion 133 is not covered with the partition wall 60, and In any case where the entire visible portion 133 is covered with the partition wall 60, substantially the same degree of visibility is ensured for the visible portion 133. In addition, when the handle portion 10 is molded in the third facing state, the partition wall 60 becomes thicker than when the handle portion 10 is molded in the first facing state and the second facing state. The bonding strength with 130 is increased.

  As described above, the convex portion interval TA is related to the formability of the handle portion 10, the visibility of the visible portion 133, and the bonding strength between the handle portion 10 and the covering portion 130 against twisting. For this reason, it is preferable that the convex part interval TA is determined from the relationship with these factors. An example of a preferable convex portion interval TA determined from the viewpoint of formability is an interval at which the end surfaces 354A and 364A and the visible portion 133 are pressure-bonded.

(Example)
The 1st-4th test implemented in order to evaluate the performance of the interdental brush 1 is demonstrated. In each test, the sample of the example and the sample of the comparative example were used. The sample of an Example is a sample regarding the interdental brush 1 of embodiment. The molding method of the handle portion 10 of each sample is the same as the molding method exemplified in the embodiment. In order to visually inspect the state of the covering portion 130 in the third test, a transparent resin material was used for manufacturing each sample. In addition, although the sample of a comparative example differs in a part of structure from the interdental brush 1 of embodiment, it uses the same name and code | symbol for the sample of an example and the sample of a comparative example below for convenience of explanation below. Yes.

  The first test will be described. In the first test, the type of the resin material constituting the handle portion 10 and the relationship between the physical property value and the strength of the handle portion 10 against fatigue were confirmed using the samples of Examples 1 to 4 and the samples of Comparative Examples 1 to 4. did. The test conditions are the type of resin material, the density of the resin material, the melting point of the resin material, the elastic modulus of the resin material, and the diameter of the core material 110. FIG. 16 shows specific test conditions. The elastic modulus of the samples of Examples 1 to 4 and Comparative Examples 1 and 3 is a bending elastic modulus. The elastic modulus of the samples of Comparative Examples 2 and 4 is the tensile elastic modulus.

  In the first test, in order to evaluate the strength of the neck portion 20 against fatigue, the first bending scheduled portion 41 is repeatedly bent so that the first angle θA (see FIG. 11) is about 90 °, and the first bending scheduled. The number of times of bending when the portion 41 broke due to fatigue (hereinafter referred to as “maximum number of bending times”) was measured. The usage pattern of the handle portion 10 was changed from the first usage pattern to the second usage pattern, and the work of changing the first usage pattern again to the first usage pattern was counted as one bending.

  As shown in FIG. 16, it was confirmed that the samples of Examples 1 to 4 had a maximum number of bending times than the samples of Comparative Examples 1 to 4. This indicates that the strength of the neck portion 20 against fatigue increases when the type of resin material and its physical property values are included in the conditions exemplified in the embodiment.

  The second test will be described. In the second test, the relationship between the degree of plastic working of the covering portion 130 and the bonding strength between the handle portion 10 and the covering portion 130 with respect to twisting was confirmed using the samples of Examples 5 to 8 and the samples of Comparative Examples 5 and 6. did. The differences between the samples of Examples 5 to 8 are the first deformation rate PA and the second deformation rate PB. The difference between the samples of Examples 5 to 8 and the samples of Comparative Examples 5 and 6 is the shape of the core material 110. The core material 110 of the sample of Comparative Example 5 has a linear shape. The core material 110 of the sample of Comparative Example 6 includes a second portion 132 formed by bending. The second portion 132 is a portion bent so that a part of the covering portion 130 protrudes in the radial direction of the covering portion 130. FIG. 17 shows specific test conditions.

  In the second test, in order to evaluate the bonding strength between the handle portion 10 and the covering portion 130 against torsion, the torque (hereinafter, “maximum torque”) when the bonding between the handle portion 10 and the covering portion 130 is released was measured. The maximum torque is measured as follows. First, the cleaning part 140 of the core material 110 is fixed to a torque gauge. Next, a torque for rotating the handle portion 10 around the central axis C of the interdental brush 1 is applied to the handle portion 10, and the torque is gradually increased so that the maximum when the handle portion 10 rotates with respect to the core member 110 is increased. Torque was measured.

  As shown in FIG. 17, it was confirmed that the samples of Examples 5 to 8 and the sample of Comparative Example 6 had a maximum torque higher than that of the sample of Comparative Example 5. This indicates that when the second portion 132 is formed on the covering portion 130, the maximum torque is increased by joining the handle portion 10 and the second portion 132. FIG. 18 is a graph showing the relationship between the first deformation ratio PA and the maximum torque for the samples of Examples 5 to 8. FIG. 19 is a graph showing the relationship between the second deformation rate PB and the maximum torque for the samples of Examples 5 to 8. The maximum torque of the samples of Examples 5 to 8 is 3.1 times or more the maximum torque of the sample of Comparative Example 5. This is because, when the second portion 132 is formed such that at least one of the first deformation rate PA and the second deformation rate PB is included in the numerical range exemplified in the embodiment, the second portion 132 is that of the comparative example 6. It shows that a high maximum torque can be obtained even if it is not a part formed by bending as in the sample.

  The third test will be described. In the third test, the relationship between the degree of plastic working of the covering portion 130 and the formability of the handle portion 10 was confirmed using the same sample as in the second test. In order to evaluate the moldability of the handle portion 10, N samples are molded, the number N1 of the first type samples, the number N2 of the second type samples included in the N samples, and the third type The number N3 of the samples was measured by visual inspection. From the results, the ratio of the number N1 of the first type sample to N pieces (hereinafter “first molding rate P1”) and the ratio of the number N2 of the second type sample to N pieces (hereinafter “second molding rate P2”). ) And the ratio of the number N3 of the third type samples to the N pieces (hereinafter, “third molding rate P3”).

  The first type of sample is a sample that satisfies the first evaluation condition. The first evaluation condition is that the handle portion 10 is covered with the covering portion 130 in a straight state. In the straight state of the covering portion 130, the central axis C of the interdental brush 1 and the entire central axis of the covering portion 130 are substantially coaxial. In the first type of sample, a straight visible portion 133 can be observed through the opening 50. For this reason, even when the grip part 30 is comprised with opaque resin, it can confirm that 1st evaluation conditions are satisfy | filled.

  The second type of sample is a sample that satisfies the second evaluation condition. The second evaluation condition is that the covering end portion 110D of the covering portion 130 is offset in a direction perpendicular to the central axis C with respect to the central axis C of the interdental brush 1, and the covering portion 130 is bent with the non-holding portion 122 as a fulcrum. It is that you are. When the handle portion 10 is molded, the visible portion 133 is detached from between the first convex portion 354 and the second convex portion 364 by the force of the resin supplied to the molding space 341, and the resin is cured in this state. A second type of sample is considered to be formed. When the amount of deflection of the covering portion 130 is large in the second type sample, the covering portion 130 is not exposed to the opening 50. When the amount of deflection of the covering portion 130 is small in the second type sample, a state in which a portion of the covering portion 130 is curved can be observed through the opening 50.

  The third type of sample is a sample that satisfies the third evaluation condition. The third evaluation condition is that the visible portion 133 is not held with the visible portion 133 in the covering portion 130 in a state where the visible portion 133 is not offset in the direction orthogonal to the central axis C with respect to the central axis C of the interdental brush 1. That is, the portion between the portion 122 is bent. When the handle portion 10 is molded, even when the resin is supplied to the molding space 341, the state where the visible portion 133 is held by the convex portions 354 and 364 is maintained, and the non-holding portion is maintained by the force of the supplied resin. It is considered that the third type sample is formed by the covering portion 130 being bent with the 122 and the visible portion 133 as a fulcrum and the resin being cured in this state. In the third type sample, the visible portion 133 inclined with respect to the central axis C of the interdental brush 1 can be observed through the opening 50.

  FIG. 20 is an example of measurement results under N = 100 test conditions. The sample of Comparative Example 6 has a lower first molding rate P1 than the samples of Examples 5 to 8 and the sample of Comparative Example 5. The reason is considered as follows. Since the second portion 132 in the sample of Comparative Example 6 is a bent portion, a large resistance is given to the flow of the resin supplied to the molding space 341, and the second portion 132 receives a large force from the resin. When the component in the direction orthogonal to the central axis of the core material 110 is strong in the force received by the second portion 132 from the resin, the visible portion 133 is disengaged from between the first convex portion 354 and the second convex portion 364, and the second A seed sample is formed. When the component in the direction along the axial direction of the core member 110 is strong in the force received by the second portion 132 from the resin, the second portion 132 is pushed toward the non-holding portion 122 and is sandwiched between the convex portions 354 and 364. A portion between the visual recognition portion 133 and the non-holding portion 122 is bent, and a third type sample is formed.

  Although the samples of Examples 5 to 8 also include the second portion 132, a relatively preferable result with respect to the first molding rate P1 because the resistance given to the resin flow is smaller than that of the second portion 132 in the sample of Comparative Example 6. It is thought that was obtained. Since the sample of Comparative Example 5 does not include the second portion 132, a relatively preferable result is obtained with respect to the first molding rate P1.

  The fourth test will be described. In the fourth test, regarding the relationship between the position of the second portion 132 in the axial direction of the covering portion 130 and the bonding strength between the handle portion 10 and the covering portion 130 with respect to torsion, the samples of Examples 9-12 and Comparative Examples 7-12. It confirmed using the sample. The samples of Examples 9 to 12 are samples related to the interdental brush 1 of the embodiment. The samples of Comparative Examples 11 and 12 include the linear core material 110 similarly to the sample of Comparative Example 5. The test conditions are the type of resin material, the density of the resin material, the melting point of the resin material, the elastic modulus of the resin material, the diameter of the material of the core material 110, the length ZA of the core material 110, the length HX of the covering portion 130, 1 deformation rate PA, 2nd deformation rate PB, and separation rate PC. FIG. 21 shows specific test conditions.

  As shown in the measurement results regarding the samples of Examples 9 to 11 and the samples of Comparative Examples 7 to 9, it was confirmed that the maximum torque increases as the separation ratio PC decreases. This is because the transmission distance of the force until the torque applied to the cleaning part 140 of the core material 110 is transmitted to the second portion 132 is long, and the torque applied to the core material 110 is in a wider range of the core material 110. It seems that being able to receive it has an influence. However, as shown in the measurement results of the sample of Example 12 and the sample of Comparative Example 10, when the length ZA of the core material 110 is greater than or equal to a predetermined length, the maximum torque is not the separation ratio PC but the core material 110. It was confirmed that it strongly depends on the length ZA. This is presumably because the transmission distance of the force becomes longer due to the length ZA of the core material 110 being longer, and the torque applied to the core material 110 can be received in a wider range of the core material 110. In addition, as shown in the measurement results of the set of Examples and Comparative Examples in which the type, density, melting point, and elastic modulus of the resin material are different and other test conditions are consistent, the higher the elastic modulus of the resin material is, It was confirmed that the maximum torque was increased. The combinations of Examples and Comparative Examples corresponding to this are the measurement results of Example 9 and Comparative Example 7, Example 10 and Comparative Example 8, Example 11 and Comparative Example 9, and Example 12 and Comparative Example 10. is there.

(Modification)
The said embodiment is an illustration of the form which the interdental brush regarding this invention can take, and it does not intend restrict | limiting the form. The interdental brush according to the present invention can take, for example, a combination of the following modification example of the above-described embodiment and at least two modification examples not inconsistent with each other.

  The configuration of the handle portion 10 can be arbitrarily changed. In the first example, the handle portion 10 does not include the first bending planned portion 41. Even in this case, the usage pattern of the interdental brush 1 can be changed similarly to the embodiment by bending the neck portion 20. Since the neck portion 20 includes the flat intermediate portion 22, the neck portion 20 can be easily bent even in the handle portion 10 from which the first bending planned portion 41 is omitted. In the second example, the handle portion 10 does not include the second bending scheduled portion 42. Even in this case, the usage pattern of the interdental brush 1 can be changed in the same manner as in the embodiment by bending the grip portion 30. In the third example, the handle portion 10 does not include the scheduled bending portion 40. Even in this case, the usage pattern of the interdental brush 1 can be changed in the same manner as in the embodiment by bending at least one of the neck portion 20 and the grip portion 30. In the fourth example, the handle portion 10 has a structure that is not distinguished from the neck portion 20 and the grip portion 30. An example of the structure is a structure in which the shape of the grip portion 30 is uniform or similar in the axial direction of the interdental brush 1 in each cross section of the grip portion 30 orthogonal to the central axis C of the interdental brush 1.

  The configuration of the opening 50 can be arbitrarily changed. In the first example, the opening 50 includes only one of the first opening 51 and the second opening 52. In the second example, one of the first opening 51 and the second opening 52 included in the opening 50 is provided in the grip 30 in the first example. In this case, the length of the covering portion 130 is determined so that the visible portion 133 is positioned on the grip portion 30. In the third example, at least one of the first opening 51 and the second opening 52 is provided in the grip portion 30. In this case, the length of the covering portion 130 is determined as in the second example. In the fourth example, the shape of the hole formed in the opening 50 is a shape other than a rectangle. Examples are squares, circles, ellipses, and triangles.

  The configuration of the core material 110 can be arbitrarily changed. In the first example, the core member 110 includes a plurality of second portions 132. In the second example, in the first example, the shape of at least one of the plurality of second portions 132 is different from the shape of the other second portions 132.

  The manufacturing method of the interdental brush 1 can be arbitrarily changed. In one example, the interdental brush 1 is manufactured by a manufacturing method using thermal welding as disclosed in JP-A-9-117324. According to this manufacturing method, first, the handle portion 10 and the brush portion 100 are individually formed. Next, the covering portion 130 of the core material 110 is heated, and the covering portion 130 is inserted into the handle portion 10 in this state. For this reason, the handle | steering-wheel part 10 and the coating | coated part 130 are welded.

DESCRIPTION OF SYMBOLS 1: Interdental brush 10: Handle part 20: Neck part 30: Grip part 40: Bending plan part 41: 1st bending plan part 41A: 1st groove | channel 42: 2nd bending plan part 42A: 2nd groove | channel 100 : Brush part 110: Core material 200: Filament bundle

Claims (11)

A handle portion made of polyolefin resin;
A brush part joined to the handle part so as to clean the teeth,
The polyolefin resin has a density in the range of 920 to 930 kg / m ³ ,
The melting point of the polyolefin resin is included in a range of 120 to 126 ° C. The interdental brush according to claim 1, wherein an elastic modulus of the polyolefin resin is included in a range of 200 to 300 MPa. The interdental brush according to claim 1, wherein the handle portion includes a planned bending portion configured to be bent in order to adjust insertion property of the brush portion between the teeth. The handle portion includes a grip portion and a neck portion,
The interdental brush according to claim 3, wherein the grip portion and the neck portion are integrally formed of the polyolefin resin. The interdental brush according to claim 4, wherein the bent portion includes a first bent portion provided on the neck portion. The brush portion includes a core material, and a bundle of filaments planted in the core material,
The interdental brush according to claim 5, wherein the first bent portion includes a first groove configured to bend the neck portion in a direction in which the brush portion falls. The interdental brush according to claim 5, wherein the planned bending portion includes a second planned bending portion provided in the grip portion. The interdental brush according to claim 7, wherein the second scheduled bending portion includes a second groove configured to be able to bend the grip portion in a direction in which the brush portion falls. The brush portion includes a core material, and a bundle of filaments planted in the core material,
The core material includes at least a covering portion coated on the neck portion,
The ratio of the thickness of the part corresponding to the said thinnest part of the said coating | coated parts with respect to the minimum dimension which is the dimension of the thinnest part in the said neck part is contained in the range of 15-45%. Interdental brush. The interdental brush according to any one of claims 1 to 9, wherein the polyolefin resin is a polyethylene resin. The interdental brush according to claim 10, wherein the polyethylene resin is a linear low-density polyethylene resin.

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