JP6435539B2 - Toothbrush bristles, manufacturing method thereof, and toothbrush - Google Patents

Description

  The present invention relates to a toothbrush bristle, a manufacturing method thereof, and a toothbrush.

A typical toothbrush includes a handle body including a handle portion and a head portion provided at the tip portion, and a hair bundle in which a plurality of toothbrush bristles are bundled on the head portion.
Known toothbrush bristles include tapered bristles whose tip ends are gradually reduced in diameter toward the tip and sharpened, straight bristles having substantially the same diameter from the base end to the tip, and the like. Among these, tapered hairs are effective in preventing periodontal disease because they can enter narrow portions such as the tooth neck and interdental portions. In addition, the tapered bristles are soft at the tip, and therefore give a gentle contact feeling in the oral cavity.
Tapered bristles can clean the narrow part well and are comfortable to touch. However, since the hair and hips are soft, there may be a feeling that the cleaning of the tooth surface and the occlusal surface is unsatisfactory.

In order to solve such a problem, so-called leading branch hairs in which the leading end is branched have been proposed.
For example, a brush has been proposed in which the cross section near the base end is a three-leaf clover type, the tip side is branched into three, and each branched hair is tapered (for example, Patent Document 1).
Also proposed is a fiber for bristle that is composed of a composite fiber composed of a resin skin layer and a core layer that do not adhere to each other, and is characterized in that the hair tip is polished and divided into a plurality of pieces (for example, Patent Document 2). .
For example, it is a sea-island type composite fiber in which 2 to 5 island parts made of polyamide resin are scattered in a sea part made of polyester resin, and a composite part consisting of an island part and a sea part over a certain length from the flocked base. As for the front side, only the island portion is exposed and 2 to 5 core hairs are formed (for example, Patent Document 3).
Alternatively, a brush monofilament whose tip is split into a plurality of pieces has been proposed (for example, Patent Document 4).

JP 2001-169827 A JP-A-9-98837 Japanese Patent Laid-Open No. 9-322821 JP 2006-207111 A

However, the invention of Patent Document 1 has a problem that when a toothbrush bristle is implanted on a flocked surface, it is easily broken and damaged by a mechanical impact. In particular, when toothbrush hair is planted with a flat-wire-type hair transplantation device, there is a problem that the toothbrush hair tends to tear when the toothbrush hair is supplied to the hair transplanter or when the toothbrush hair is driven into the planted surface. The inventions of Patent Documents 2 to 3 have a problem that the manufacturing process is complicated and the cost is high. The invention of Patent Document 4 has a problem that it is difficult to control the length and thickness of the branching portion.
In addition, the toothbrush bristle is required to further improve the cleaning properties of the tooth surface, the occlusal surface and the narrow portion.
Then, this invention aims at the hair for toothbrushes which is excellent in the cleaning property of a tooth surface, an occlusal surface, and a narrow part, can be manufactured easily, and is excellent in the manufactureability of a toothbrush.

The bristle for toothbrush of the present invention includes a substantially cylindrical body extending from the base end toward the tip, and a plurality of branch portions extending to the body, and the branch portion is gradually reduced in diameter toward the tip. In the toothbrush bristle having a shape to be formed, the trunk portion is formed with a reduced diameter portion that gradually decreases in diameter toward the branch portion near the proximal end of the branch portion.
The cross-sectional shape of the branch portion is preferably a substantially polygonal shape.

  The toothbrush of the present invention is characterized in that the toothbrush bristle of the present invention is implanted.

 The method for manufacturing a toothbrush bristle according to the present invention is a method of bundling resin fibers into a fiber bundle, directing an arbitrary end face of the fiber bundle vertically downward, and removing the fiber bundle with an arbitrary length from the arbitrary end face. The method for producing the toothbrush bristle according to the present invention, comprising a step of immersing in a fiber, wherein the fiber has a hollow portion extending in a length direction thereof.

  According to the toothbrush bristles of the present invention, the tooth surface, the occlusal surface, and the narrow portion are excellent in cleanability, can be easily manufactured, and are excellent in toothbrush manufacturing suitability.

It is a front view of the hair for toothbrushes concerning a first embodiment of the present invention. It is II-II sectional drawing of the bristle for toothbrush of FIG. It is a front view of the fiber which is a material of the toothbrush bristle of FIG. It is IV-IV sectional drawing of FIG. It is a front view of the bristle for toothbrush concerning 2nd embodiment of this invention. It is VI-VI sectional drawing of FIG. It is VII-VII sectional drawing of FIG. It is sectional drawing of the bristle for toothbrush concerning one Embodiment of this invention. It is sectional drawing of the bristle for toothbrush concerning one Embodiment of this invention.

(First embodiment)
The toothbrush bristles according to the first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a state in which the toothbrush bristles of the present embodiment are implanted on the flocked surface.
As shown in FIG. 1, the toothbrush bristle 1 includes a body part 10 and three branch parts 20 extending from the body part 10.

 The trunk portion 10 has a substantially columnar shape extending from the proximal end 11 toward the distal end 21 in a state where the toothbrush bristles 1 are implanted on the flocked surface 40. In the present embodiment, the trunk portion 10 is formed with a trunk straight portion 12 having substantially the same diameter from the proximal end 11 toward the distal end 21 near the proximal end 11, and continues to the trunk straight portion 12. A body diameter-reduced portion 14 that gradually decreases in diameter toward a boundary 22 (branch portion base end) 22 with the branch portion 20 is formed. The toothbrush bristle 1 is formed with the waist-reduced diameter portion 14, so that the entire body flexes flexibly from the body portion 10 to the branching portion 20, and the tooth surface, the occlusal surface, and the narrow portion are excellent in cleanability. .

The length L0 of the trunk straight portion 12 can be determined in consideration of the entire length of the toothbrush bristle 1.
The thickness of the trunk straight portion 12, that is, the maximum diameter R1 of the trunk portion 10 is determined in consideration of the material and the like, and is preferably 100 to 300 μm, and more preferably 150 to 250 μm. If it is less than the above lower limit, the hair and hips become too soft and there is a risk that the actual feeling of cleaning of the tooth surface and the occlusal surface will be lowered. If it exceeds the above upper limit value, the cleanability of the narrow portion may be lowered, or the contact comfort may become hard.

The length L1 of the trunk diameter portion 14 can be determined in consideration of the material and the like according to the rigidity and the like required for the toothbrush bristle 1 and is, for example, 0.5 to 15 mm. The length L1 of the trunk reduced diameter portion 14 is adjusted by a combination of the type of solvent and the immersion time in the immersion process described later.
The minimum diameter of the trunk reduced diameter portion 14, that is, the thickness R2 of the trunk portion 10 at the boundary between the trunk portion 10 and the branching portion 20, for example, is preferably 30 to 99% of R1, and more preferably 60 to 95%. If it is less than the above lower limit, the length L2 of the branching portion 20 is shortened and the effect thereof is difficult to be exhibited, and the hair and hips become too soft, and there is a risk that the cleaning feeling of the tooth surface, the occlusal surface and the like will deteriorate. If it exceeds the above upper limit value, the cleanability of the narrow portion may be lowered, or the contact comfort may become hard.

 As shown in FIG. 2, a hollow portion 16 extending in the length direction is formed around the central axis O <b> 1 of the trunk portion 10 in the trunk portion 10. In this embodiment, the cross-sectional shape of the hollow portion 16 is a substantially isosceles triangle whose apex angle is located in the vicinity of the central axis O1 of the trunk portion 10, and the hollow portion 16 is annularly arranged around the axis of the central axis O1. ing. The substantially isosceles triangle is a concept including a shape in which a part or all of the sides are arcuate and a shape in which each vertex is cut off by a straight line or a curve.

The branch portion 20 has a so-called taper shape in which the diameter gradually decreases toward the tip 21 and the tip 21 is sharpened. As shown in FIG. 2, the cross-sectional shape of the branch portion 20 is a substantially isosceles triangle whose apex angle is located near the central axis O <b> 1 of the toothbrush bristle 1. Note that the cross-sectional shape of the branching portion 20 approaches a circle as it goes toward the tip 21.
The outer peripheral surface of the branch portion 20 is continuous with the outer peripheral surface of the trunk portion 10 and the inner peripheral surface of the hollow portion 16, and the toothbrush bristle 1 as a whole gradually decreases in diameter from the proximal end 11 toward the distal end 21. The shape is made.
In the present embodiment, the branch portions 20 have substantially the same shape and substantially the same size.

 The length of the branching portion 20, that is, the length L2 from the branching portion proximal end 22 to the distal end 21 can be determined in consideration of the material and the like according to the rigidity required for the toothbrush bristle 1, for example, 0.5-10 mm Is preferable, and 2 to 4 mm is more preferable. If it is less than the above lower limit value, there is a risk that the cleaning property of the narrow portion will be lowered or the contact comfort may become hard. Actual feeling may be reduced. The length L2 of the branch part 20 is adjusted by the combination of the type of solvent and the immersion time in the immersion process described later.

  The tip diameter of the branch portion 20 (the portion that is offset by 0.1 mm from the tip 21 to the branch base end 22) R3 is preferably, for example, 10 to 100 μm, and more preferably 10 to 60 μm. The tip diameter R3 is a diameter of a circle in which the cross section of the branch portion 20 is inscribed.

The toothbrush bristle 1 is formed by integrally forming a body portion 10 and a branch portion 20.
The material of the toothbrush bristle 1 is not limited as long as it is generally used as a toothbrush bristle. For example, polyester such as polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), 612 Examples thereof include polyamides such as nylon and 610 nylon, and resins such as polyolefins such as polyethylene (PE) and polypropylene (PP). Among them, polyester is preferable because it is easy to process. These resins can be used singly or in combination of two or more, but are preferably monofilaments made of a single material from the viewpoints of investment cost of manufacturing equipment, maintainability, and appearance quality stability.

  The method for manufacturing the toothbrush bristle 1 is a method of bundling resin fibers to form a fiber bundle (bundle forming step), directing an arbitrary end surface of the fiber bundle vertically downward, and an arbitrary length from the arbitrary end surface. What has the process (immersion process) of immersing a bundle in a solvent is mentioned.

In the bundle forming step, an arbitrary number of resin fibers are bundled to obtain a fiber bundle. The number of fibers in the fiber bundle in the bundle forming step can be determined in consideration of production efficiency and the like.
The resin fibers 5 used for manufacturing the toothbrush bristle 1 will be described with reference to FIGS. The fiber 5 shown in FIG. 3 has a columnar shape with substantially the same diameter from one end 51 to the other end 52, and three hollow portions 16 extending in the length direction are formed therein. .
The fiber 5 is manufactured by, for example, an extrusion molding machine in the same manner as a general method for manufacturing hollow hair. As a manufacturing method by an extrusion molding machine, the method similar to the manufacturing method of the filament of the above-mentioned patent document 4 is mentioned, for example.
The length of the fiber 5 can be determined in consideration of the length of the intended toothbrush bristles 1, the flocking method, and the like. It is said to be about.

In the dipping process, an arbitrary end face of the fiber bundle is dipped in a solvent to form the branch part 20 and the trunk diameter part 14.
The solvent used in the dipping step can be determined according to the type of the fiber 5, and examples thereof include alkaline solutions such as sodium hydroxide solution and potassium hydroxide solution, acidic solutions such as sulfuric acid solution, and organic solvents. Alkaline solutions are preferred.
When using a sodium hydroxide solution as a solvent, the density | concentration of sodium hydroxide shall be 40-50 mass%, for example.
Moreover, the temperature of a sodium hydroxide solution shall be 120-140 degreeC, for example.
The length of immersing the fiber bundle in the solvent can be appropriately determined in consideration of the desired length of the branching portion 20 and the like.

When the fiber bundle is immersed in the solvent, the solvent dissolves around the outer periphery of the fiber 5 and dissolves the fiber 5 while the solvent crawls up between the fibers 5 and in the hollow portion 16. And are formed.
After immersing in a solvent for an arbitrary time, the fiber bundle is taken out from the solvent, neutralized as necessary, and then washed with water.
The branch part 20 may be formed only at one end of the toothbrush bristle 1 or may be formed at both ends.

  The toothbrush bristles 1 thus obtained are, for example, planted on the flocked surface 40 by a flat-line type flocking method, or flocked on the flocked surface 40 by an in-mold method to form a toothbrush.

  According to the toothbrush bristles of this embodiment, since the tip is provided with a sharpened branch portion, narrow portions such as between teeth and the neck portion can be cleaned well, and the trunk portion connected to the branch portion is more than the branch portion. Because it is thick, it exhibits strong fur and can clean the tooth surface and occlusal surface well. In addition, since the body diameter part is formed in the body part, it flexes smoothly from the body part to the branch part, the bristle and hips do not become too hard, the gentle contact comfort, the narrow part, the tooth surface and the occlusal surface It can be cleaned well.

  According to this embodiment, since the trunk | drum is made into the substantially cylindrical shape, it can prevent that the hair for toothbrushes tears by the impact etc. in the case of flocking. In particular, when flocking with a flat wire type flocking device, it is possible to prevent the toothbrush bristles from being damaged when the toothbrush bristles are supplied to the flocking machine or when the toothbrush bristles are driven into the flocking surface.

  According to this embodiment, since the cross-sectional shape of the branch portion is substantially triangular, the narrow portion can be cleaned more favorably by scraping the plaque with the ridgeline that forms each vertex of the cross-sectional shape.

  According to this embodiment, the toothbrush bristle provided with the tapered branch portion can be manufactured by a simple method of immersing the fiber bundle in the solvent.

(Second embodiment)
Toothbrush bristles according to a second embodiment of the present invention will be described below with reference to the drawings. This embodiment differs from the first embodiment in the number of branch portions and the cross-sectional shape thereof.
However, this embodiment is a reference example.

As shown in FIG. 5, the toothbrush bristle 100 includes a body part 110 and four branch parts 120 extending from the body part 110.
The trunk portion 110 has a substantially cylindrical shape extending from the base end 111 toward the tip 121 in a state where the toothbrush bristles 100 are planted on the flocked surface 40. In the present embodiment, the trunk portion 110 is formed with a trunk straight portion 112 having substantially the same diameter near the base end 111, and continues to the trunk straight portion 112, and a trunk reduced diameter portion 114 that gradually decreases in diameter toward the branch base end 122. Is formed.
As shown in FIGS. 6 to 7, a hollow portion 116 extending in the length direction is formed in the body portion 110. The hollow part 116 hollows the body part 110 into a substantially cylindrical shape. In the trunk portion 110, four substantially cylindrical branch base portions 130 extending in the length direction of the trunk portion 110 are formed in contact with the inner peripheral surface of the trunk portion 110 around the central axis O2.

The branching portion 120 has a so-called taper shape in which the diameter gradually decreases toward the tip 121 and the tip 121 is sharpened. As shown in FIG. 6, the cross-sectional shape of the branch portion 120 is a substantially perfect circle.
The outer peripheral surface of the branch portion 120 is continuous with the outer peripheral surface of the trunk portion 110 and the outer peripheral surface of the branch base portion 130, and the toothbrush bristles 100 are gradually reduced in diameter from the base end 111 toward the tip 121 as a whole. It is made into a shape.
In the present embodiment, the branch portions 120 have substantially the same shape and substantially the same size.

The length of the trunk straight portion 112 is the same as the length of the trunk straight portion 12, and the thickness of the trunk straight portion 112 is the same as the thickness of the trunk straight portion 12.
The length of the trunk diameter portion 114 is the same as the length of the trunk diameter portion 14, and the minimum diameter of the trunk diameter portion 114 is the same as the minimum diameter of the trunk diameter portion 14.
The length of the branch part 120 is the same as the length of the branch part 20, and the tip diameter of the branch part 120 is the same as the tip diameter of the branch part 20.
The material of the toothbrush bristle 100 is the same as that of the toothbrush bristle 1.

  According to this embodiment, since the cross section of the branch part is circular, the fur of the branch part is soft and the hit feeling is more gentle.

(Other embodiments)
The present invention is not limited to the above-described embodiment.
In the first embodiment, the cross-sectional shape of the branch portion is a substantially triangular shape, but the present invention is not limited to this, and the cross-sectional shape of the branch portion is a circle such as a true circle or an ellipse, a substantially quadrangular shape, or a substantially pentagonal shape. It may be a substantially polygon other than a triangle.
In the second embodiment, the cross-sectional shape of the branch portion is a substantially circular shape, but the present invention is not limited to this, and may be an elliptical shape, a substantially triangular shape, a substantially rectangular shape, a substantially pentagonal shape, or the like. It may be a substantially polygon.
However, from the viewpoint of improving the cleanability, the cross-sectional shape of the branch portion is preferably a substantially polygonal shape.

In the first embodiment, three branch portions are formed, but the present invention is not limited to this, and the number of branch portions may be two or four or more. .
In the second embodiment, four branch portions are formed, but the present invention is not limited to this, and the number of branch portions may be two to three, or five or more. Also good.
However, from the viewpoint of providing an appropriate bristle waist at the branch portion to improve the cleaning property and obtaining a gentle contact feeling, the number of branch portions is preferably 3 to 10, and more preferably 3 to 5.

In the first embodiment, the three hollow portions are formed independently, but the present invention is not limited to this. For example, the plurality of hollow portions are connected in a region including the central axis, and from the vicinity of the central axis. A radially extending cross-sectional shape, that is, a cross shape, a star shape, or the like may be used.
The toothbrush bristle in which such a hollow portion is formed will be described with reference to FIG. However, the toothbrush bristle shown in FIG. 8 is a reference example. FIG. 8A is a cross-sectional view at the same position as in FIG. 2, and FIG. 8B is a cross-sectional view of the body portion. As shown in FIGS. 8A and 8B, the toothbrush bristle 200 includes a substantially cylindrical body 210 and four branch portions 220, and the body 210 has a body straight portion 212 and a body diameter-reduced portion. 214 is formed.
The cross-sectional shape of the branch part 220 is substantially triangular, and approaches a circular shape as it goes toward the tip. A hollow portion 216 having a substantially cross-shaped cross section is formed in the body portion 210.
When the hollow portion 216 is connected in a region including the central axis O3 like the toothbrush bristles 200, it is preferable in that the solvent can easily enter deeply in the dipping process and the length of the branch portion 220 can be increased.

  In the first and second embodiments, the branch portions have substantially the same shape and substantially the same size, but the present invention is not limited to this, and some branch portions and other branch portions However, the shape or size may be different, or all the branch portions may be different in shape or size. For example, the cross-sectional shape of some of the branch portions may be substantially polygonal, the cross-sectional shape of some of the branch portions may be substantially circular, or the cross-sectional shapes of the branch portions may be substantially polygons different from each other. Also good. In addition, for example, the branch portions may have the same cross-sectional shape and different thicknesses.

Toothbrush bristles in which the size of some branch portions are different from those of other branch portions will be described with reference to FIG. However, the toothbrush bristle shown in FIG. 9 is a reference example. FIG. 9A is a cross-sectional view at the same position as in FIG. 2, and FIG. 9B is a cross-sectional view of the trunk. As shown in FIGS. 9A and 9B, the toothbrush bristle 300 includes a substantially cylindrical body 310, three first branch portions 320, and three second branch portions 322. The trunk portion 310 is formed with a trunk straight portion 312 and a trunk reduced diameter portion 314.
The cross-sectional shape of the first branch part 320 is a substantially triangular shape, and is closer to a circle as it goes to the tip. The cross-sectional shape of the second branch portion 322 is a substantially triangular shape, and approaches a circular shape toward the tip.
In the toothbrush bristles 300, the cross-sectional shape of the first branch part 320 and the cross-sectional shape of the second branch part 322 are substantially the same, and the cross-sectional area of the first branch part 320 is the same as that of the second branch part 322. It is larger than the area.

The body portion 310 has a circular hollow portion 318 having a substantially circular cross section in a region including the central axis O4, and has a cross section shape extending radially from the circular hollow portion 318 toward the outer peripheral surface of the body portion 310. A rectangular hollow portion 319 is formed. The barrel portion 310 includes an arbitrary rectangular hollow portion 319 and three rectangular first branch bases 330 by the optional rectangular hollow portion 319 and another rectangular hollow portion 319 that is adjacent in the circumferential direction of the barrel portion 310. Three second branch bases 332 are formed. The first branch base 330 and the second branch base 332 have a substantially triangular cross-sectional shape and are different from each other in cross-sectional area. In addition, the first branch base 330 and the second branch base 332 are alternately positioned in the circumferential direction of the body 310.
The first branch portion 320 is substantially flush with the outer peripheral surfaces of the first branch base portion 330 and the body portion 310, and the second branch portion 322 is formed with the outer peripheral surfaces of the second branch base portion 332 and the body portion 310. It is considered to be almost the same.
The toothbrush bristles 300 are improved in cleanability by the first branch portion 320 having a relatively hard bristle, and the gentle contact feeling is enhanced by the second branch portion 322 having a relatively soft bristle.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated in detail, this invention is not limited by the following description.

Example 1
PBT is extruded by extrusion to obtain a fiber having a hollow portion, and this fiber is immersed in a solvent (50% by mass sodium hydroxide) to obtain a toothbrush hair similar to the toothbrush hair 1 of the first embodiment. It was. The specifications of the obtained toothbrush bristle were as shown in Table 1. Since the toothbrush bristles were obtained by a method of immersing in a solvent (in the table, this processing method is described as “dissolution”), the production efficiency was high.
Next, 10 toothbrush bristles were folded in half so that the number of hairs per hair bundle was 20, and planted in 4 rows x 7 stages to obtain a toothbrush. About the obtained toothbrush, flocking aptitude, narrow part cleanability, and surface cleanability were evaluated, and the results are shown in Table 1.

(Example 2)
A toothbrush was obtained in the same manner as in Example 1 except that the toothbrush bristles were the same as the toothbrush bristles 100 of the second embodiment. About the obtained toothbrush, flocking aptitude, narrow part cleanability, and surface cleanability were evaluated, and the results are shown in Table 1.
However, Example 2 is a reference example.

(Comparative Example 1)
PBT is extruded by extrusion to obtain a clover-type (multi-leaf) fiber having a cross-sectional shape, and the fiber is immersed in a solvent (50% by mass sodium hydroxide). A toothbrush was obtained in the same manner as in Example 1 except that hair was obtained. About the obtained toothbrush, flocking aptitude, narrow part cleanability, and surface cleanability were evaluated, and the results are shown in Table 1.

(Comparative Example 2)
According to Patent Document 2, a toothbrush was obtained in the same manner as in Example 1 except that a fiber having a skin layer made of nylon and a core layer made of PBT was polished to obtain toothbrush bristles. The toothbrush bristles were complicated in terms of the production of fibers composed of a plurality of layers and the formation of branch portions by polishing (this processing method is referred to as “polishing” in the table). About the obtained toothbrush, flocking aptitude, narrow part cleanability, and surface cleanability were evaluated, and the results are shown in Table 1.

(Comparative Example 3)
According to Patent Document 3, a toothbrush was obtained in the same manner as in Example 1 except that the island part was made of nylon and the sea part was made of PBT. The toothbrush bristles have a complicated manufacturing method in terms of manufacturing sea-island structure fibers. About the obtained toothbrush, flocking aptitude, narrow part cleanability, and surface cleanability were evaluated, and the results are shown in Table 1.

(Comparative Example 4)
A toothbrush was obtained in the same manner as in Comparative Example 1 except that the cross-sectional shape of the fiber was a circular shape having a diameter of 120 μm and four circular shapes having a diameter of 60 μm arranged in a ring (multi-leaf type). About the obtained toothbrush, flocking aptitude, narrow part cleanability, and surface cleanability were evaluated, and the results are shown in Table 1.

(Comparative Example 5)
According to Patent Document 4, PBT was extruded by extrusion to form six vesicles, and a fiber having a substantially circular cross section was obtained. One end of the fiber was treated with a rotary blade to obtain a toothbrush bristle having a branch portion (this processing method is referred to as “cut” in the table). Using the obtained toothbrush bristles, a toothbrush was obtained in the same manner as in Example 1. The obtained toothbrush was evaluated for flocking aptitude, narrow portion cleaning property, and surface cleaning property, and the results are shown in Table 1.

(Evaluation method)
<Flocking aptitude>
About the toothbrush of each example, the hair for toothbrush planted by hair was observed visually, and the thing in which damage was not recognized was evaluated as "(circle)", and the thing in which damage was recognized was evaluated as "x".

<Narrow part cleanability>
The oral cavity was cleaned using the toothbrush of each example, and narrow part cleanability was evaluated according to the following evaluation criteria.

≪Evaluation criteria≫
A: The feeling that the dental plaque was removed is very felt.
○: Feeling that the plaque of the tooth neck has been removed.
(Triangle | delta): There is not much feeling that the plaque of a tooth neck part was removed.
X: The feeling that the dental plaque was removed is not felt at all.

<Surface cleaning>
The oral cavity was cleaned using the toothbrush of each example, and narrow part cleanability was evaluated according to the following evaluation criteria.

≪Evaluation criteria≫
A: A feeling that the plaque on the tooth surface and the occlusal surface is removed is very felt.
○: Feels that the plaque on the tooth surface and occlusal surface has been removed.
(Triangle | delta): There is not much feeling that the plaque of a tooth surface and an occlusal surface was removed.
X: The feeling that the plaque on the tooth surface and the occlusal surface was removed is not felt at all.

As shown in Table 1, in Examples 1 and 2 to which the present invention was applied, the flocking aptitude was good, and the narrow portion cleaning property and the surface cleaning property were “◯” or “◎”. In addition, since the toothbrush bristles of Examples 1 and 2 have high production efficiency and are obtained by processing fibers made of a single material, they can be manufactured at a relatively low cost.
On the other hand, Comparative Examples 1 and 4 obtained by processing multi-leaf type fibers had a flocking aptitude of “x” because the trunk portion was not substantially circular.
In Comparative Example 2, a fiber having a multilayer structure was used, and this was polished to form a branch portion. Therefore, the production efficiency was low. In addition, the narrow portion cleanability was “Δ”.
In Comparative Example 3, since the shape of the branch portion was straight, the narrow portion cleanability was “Δ”.
In Comparative Example 5, since the shape of the branch portion was straight, the narrow portion cleanability was “Δ”.
From the above results, it was found that the toothbrush bristles to which the present invention is applied have excellent cleaning properties of the tooth surface, the occlusal surface and the narrow portion, can be easily manufactured, and are excellent in manufacturing suitability of the toothbrush.

1, 100, 200, 300 Toothbrush bristle 5 Fiber 10, 110, 210, 310 Body 11, 111 Base end 12, 112, 212, 312 Body straight part 14, 114, 214, 314 Body diameter reduced part 16, 116 216, 316 Hollow part 20, 120, 220, 320, 322 Branch part 21, 121 Tip 22, 122 Branch part base end

Claims (4)

A substantially cylindrical body extending from the proximal end toward the distal end and 3 to 5 branch portions extending from the body portion, and the branch portion has a shape that gradually decreases in diameter toward the distal end. In toothbrush bristles,
The material is polyester,
The body portion is formed with a reduced diameter portion that gradually decreases in diameter toward the branch portion near the proximal end of the branch portion,
The maximum diameter of the trunk is 100 to 300 μm,
The length of the reduced diameter portion is 0.5 to 15 mm,
The minimum diameter of the reduced diameter portion is 60 to 95% of the maximum diameter of the trunk portion,
The body portion is formed with three to five hollow portions extending in the length direction thereof and spaced apart from each other around the central axis of the body portion, and a hollow portion is formed in a region including the central axis. Not
The hollow portion is a substantially isosceles triangle in which a cross-sectional shape orthogonal to the central axis is an apex angle toward the central axis,
The branch portion is provided so as to protrude from a region between the hollow portions,
The outer peripheral surface of the branch portion is flush with the outer peripheral surface of the trunk portion and the inner peripheral surface of the hollow portion,
Cross-sectional shape of the base end vicinity of the bifurcation, Ri substantially isosceles triangle der,
The tip diameter of the branch portion is 10 to 60 μm,
The length of the branch portion, bristles toothbrush, wherein 0.5~10mm der Rukoto. The bristle for toothbrush according to claim 1, wherein a cross-sectional shape of the branch portion becomes circular as it goes to the tip.   A toothbrush comprising the toothbrush bristle according to claim 1 or 2 implanted therein. 3. A process comprising bundling resin fibers to form a fiber bundle, directing an arbitrary end face of the fiber bundle vertically downward, and immersing the fiber bundle in a solvent at an arbitrary length from the arbitrary end face. A method for producing toothbrush bristle according to claim 1,
In the fiber, three to five hollow portions extending in the length direction are formed apart from each other around the central axis of the fiber, and a hollow portion is formed in a region including the central axis. Not
The hollow portion is a substantially isosceles triangle in which a cross-sectional shape orthogonal to the central axis is an apex angle toward the central axis,
The fiber bundle is immersed in the solvent, the solvent dissolves around the outer periphery of the fiber, and the solvent dissolves while the solvent crawls up between the fibers and in the hollow portion, and the branched portion and the reduced diameter portion A method for producing toothbrush bristle, characterized in that

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