JP2008154888A - Toothbrush bristle, toothbrush using the same, and method for manufacturing toothbrush bristle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothbrush bristle which has a high entering property into a space between teeth and strength, and at the same time, can suppress an irritation to the gingiva, and has both of an excellent scraping force and durability, and also, can reduce pains at the time of use, to provide a toothbrush using the same, and also, to provide a method for manufacturing the toothbrush bristle. <P>SOLUTION: This toothbrush bristle includes a core section 2, and a sheath section 3 which concentrically covers the core section 2. At least one end side of the bristle is formed into a tapered section 1a, and the core section 2 is made of a resin containing a polybutylene terephthalate (PBT). At the same time, the sheath section 3 is made of a resin containing a polyethylene terephthalate (PET). At the tapered section 1a, the toothbrush bristle is formed in such a manner that the core section 2 may be exposed from the sheath section 3, and at the same time, the tapered shape is formed in a manner to continue to both of the core section 2 and the sheath section 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a brush for a toothbrush having a multilayer structure (core-sheath structure) in which a sheath part is concentrically covered on a core part, a toothbrush using the same, and a method for producing a toothbrush brush.

  Conventionally, materials such as nylon, polyethylene terephthalate (PET), and polybutylene terephthalate (PBT) have been used as brushes for toothbrushes. These materials have high bend recovery (brush durability), and there is no brittle fracture (breakage) due to significant chemical changes or tearing due to scratches even during continuous use with dentifrices. Because of its low cost, it is widely used as a toothbrush brush.

  In order to prevent dental caries and periodontal disease, it is important to remove plaque with a toothbrush, and toothbrushes with various brushes have been commercialized. In particular, in order to make it easier for the brush to reach the tooth neck and interdental sites, which are caries-prone sites, toothbrushes having brushes with tapered tips are proposed (for example, patents). Reference 1). According to the toothbrush described in Patent Document 1, since the brush tip easily enters a narrow gap such as a tooth neck portion or an interdental portion, the effect of touching the teeth and gums becomes a soft touch. is there.

  However, the toothbrush described in Patent Document 1 has a problem that the brushing force is inferior due to the weakness of the brush. In addition, since the brush tip easily enters the gingival sulcus, there is a problem that it is easy to cause pain due to such penetration. Increasing the brushing force can be achieved by thickening the taper bristles, but in this case, the pain caused in the gingiva also increases, so that both the brushing force is improved and the pain is reduced. It was very difficult to plan.

  In order to solve the problems of the brush with the bristles formed in a tapered shape as described above, the brush has a double-core-sheath structure, a sheath portion made of a soft plastic material such as an elastomer, polyamide, polyester, etc. A toothbrush having a structure in which a brush formed of a core portion made of a harder material is implanted is proposed (for example, Patent Document 2). According to the toothbrush described in Patent Document 2, since the tip of the brush can easily enter a narrow gap between teeth or a cleft of the tooth, the tip of the soft material can effectively wipe off the dirt. It becomes.

  However, in the toothbrush of patent document 2, since the core part of a brush consists of a hard material, when a taper-shaped front-end | tip part is made thin in order to make it easy to reach the narrow gap between teeth, it is based on a hard core part. There is a problem that irritation to the gingiva increases and the pain felt by the user increases.

  Further, the brush implanted on the brush surface of the toothbrush is a core-sheath composite filament (brush) in which a sheath is disposed around one core, and the core is exposed at the tip side. In particular, a toothbrush has been proposed in which the cross-sectional area of the core portion is in the range of 15 to 80% of the cross-sectional area of the composite filament (for example, Patent Document 3). In the toothbrush described in Patent Document 3, the core part is made of a material mainly containing a polyamide resin, the sheath part is made of a material mainly containing a polyester resin, and the tip side of the composite filament is an alkaline solution. The core portion is exposed by immersing in the substrate. With such a configuration, the toothbrush of Patent Document 3 maintains moderate brushing and a good brushing effect, does not hurt the gums, can improve the cleanability of details, and is durable. Is also considered excellent.

However, in the toothbrush of Patent Document 3, since the core portion is made of a material mainly composed of polyamide resin, it does not dissolve in an alkaline solution, and has a problem that the interdental penetration is inferior because it is a cylindrical core portion. is there. Also, when the sheath part is dissolved using an alkaline solution, the exposed part from the sheath part of the core part is a step, so this part is easy to peel off, and when this part peels off There is a problem that the scrubbing force and durability are lowered.
For this reason, in order to improve the interdental penetration of the brush of the toothbrush, it is necessary to form the tip of the brush in a tapered shape. However, in the toothbrush described in Patent Document 3, the core portion is mainly composed of the polyamide resin. Since it consists of the material used as a component, even if it is immersed in an alkaline solution, the tip side of the core cannot be tapered. Therefore, in order to taper the tip side of the core part, it is necessary to process the core part by mechanical polishing. When the core part is formed into a tapered shape by such a processing method, it is immersed in an alkaline solution. Since the tip diameter cannot be processed thinly as in the processing, there is a problem that the interdental penetration of the obtained brush is inferior.
JP-A-6-141923 Special table 2003-504100 gazette JP 2006-149419 A

  The present invention has been made in view of the above problems, has high interdental penetration and strength, can suppress stimulation to the gums, has both excellent scrubbing force and durability, It is an object of the present invention to provide a toothbrush brush capable of reducing pain during use, a toothbrush using the same, and a method for producing a toothbrush brush.

  As a result of intensive studies by the present inventors in order to solve the above-mentioned problems, it is used in a toothbrush brush having the above-described core-sheath structure, the tip side being tapered and the core part being exposed from the sheath part By optimizing the material and dimensional relationship, it has been found that it has both excellent brushing power and durability, excellent interdental penetration, and suppression of gingival irritation. did.

That is, the present invention is a toothbrush brush comprising a core portion and a sheath portion that covers the core portion concentrically, and at least one end side is formed as a tapered portion, wherein the core portion is polybutylene terephthalate ( PBT) and the sheath part is made of a resin containing polyethylene terephthalate (PET), and the taper part is formed such that the core part is exposed from the sheath part, and the core part And a brush for a toothbrush, wherein a taper shape is formed so as to be continuous with both of the sheath portions.
The toothbrush brush according to the present invention is a toothbrush brush having the above-described configuration, wherein the tapered portions are formed at both ends of the brush, and the outer diameter of the brush in the longitudinal center is 0.18 to 0. The outer diameter at the tip of the brush is in the range of 0.005 to 0.04 mm, and the thickness of the sheath at the center in the longitudinal direction of the brush is 0.01 to 0.02 mm. It is preferable that the length of the core portion exposed from the sheath portion in the tapered portion is in the range of 4 to 7 mm from the exposed position to the tip portion.

  The present invention provides a toothbrush in which a brush for a toothbrush having the above-described configuration is refracted in half at a substantially central portion, and a bundle of brushes in which a plurality of these are bundled is implanted.

  The present invention relates to a method for producing a brush for toothbrush, wherein a core part and a sheath part that covers the core part concentrically are formed, and at least one end side is formed as a taper part, wherein the core part is polybutylene. The resin is a resin containing terephthalate (PBT), the sheath is a resin containing polyethylene terephthalate (PET), the taper is formed by dissolution treatment with an alkaline solution, and the core is formed in the sheath at the taper And a tapered shape is formed so as to be continuous with both the core portion and the sheath portion.

According to the brush for toothbrushes of the present invention, at least one end side is formed as a taper portion, the core portion is made of a resin containing polybutylene terephthalate (PBT) that is soft (low rigidity), and the sheath portion is hard (high rigidity). Made of a resin containing polyethylene terephthalate (PET), and the taper portion is formed so that the core portion is exposed from the sheath portion, and the taper shape is formed so as to continue to both the core portion and the sheath portion Therefore, it has high interdental penetration and strength, and can suppress irritation to gingiva. As a result, a toothbrush brush and a toothbrush using the same can be obtained, which have both excellent wiping force and durability and can reduce pain during use.
Further, according to the method for manufacturing a toothbrush brush of the present invention, the core portion is made of a resin containing PBT, the sheath portion is made of a resin containing PET, the brush is immersed in an alkaline solution, and the tip is tapered. Therefore, the toothbrush brush provided with the tapered portion having the above-described configuration can be easily manufactured with simple equipment. Thereby, it becomes possible to suppress an increase in the manufacturing cost of the toothbrush brush and the toothbrush using the same.

Hereinafter, an embodiment of a toothbrush brush according to the present invention, a toothbrush using the same, and a method for producing a toothbrush brush will be described with reference to FIGS.
FIG. 1 and FIG. 2 are schematic views showing an example of a toothbrush brush according to the present invention, respectively. For convenience of explanation, only one end side of the toothbrush brush is shown enlarged. Moreover, Fig.3 (a) is a schematic diagram which shows the whole brush for toothbrushes, FIG.3 (b) is sectional drawing. 4A and 4B are schematic views showing an example of a toothbrush in which the brush for toothbrush according to the present invention is used.

  The toothbrush brush 1 of the present embodiment includes a core portion 2 and a sheath portion 3 that covers the core portion 2 concentrically, at least one end side is formed as a tapered portion 1a, and the core portion 2 is polybutylene terephthalate. (PBT) and a sheath portion 3 made of a resin containing polyethylene terephthalate (PET). In the taper portion 1a, the core portion 2 is exposed from the sheath portion 3, and the core portion. A tapered shape is formed so as to be continuous with both the sheath 2 and the sheath 3, and is roughly configured.

[Toothbrush]
Hereinafter, an example of a toothbrush in which the brush for toothbrush according to the present invention is used will be described.
The toothbrush 10 illustrated in FIGS. 4A and 4B includes a head unit 12 in which the brush bundle 11 is implanted on the flocked surface 12a, a gripping unit 13 that a user grips, a head unit 12 and a gripping unit 13. And a neck portion 14 for connecting the two. Here, the brush bundle 11 is formed by bending the toothbrush brush 1 of the present embodiment in half at a substantially central portion and converging a plurality thereof.

Although it does not specifically limit as a material of the holding part 13, For example, a polypropylene, polyethylene, a polyethylene terephthalate, a saturated polyester resin, a polymethyl methacrylate, a cellulose propionate, a polyurethane, polyamide, ABS (acrylonitrile butadiene styrene) etc. The synthetic resin material can be used. Of these, polypropylene is preferably used in terms of cost, and saturated polyester resin is preferably used in terms of transparency.
The head portion 12 and the neck portion 14 can also be made of the same material as that of the gripping portion 13. In the illustrated toothbrush 10, the head portion 12, the neck portion 14 and the gripping portion 13 are integrally formed.

  The head portion 12 is provided with a flocking surface 12a on which the brush bundle 11 (toothbrush brush 1) is implanted, and a plurality of unillustrated abundant brush bundles 11 are implanted on the flocking surface 12a. A flocked hole is formed.

  As described above, the brush bundle 11 is composed of a plurality of unillustrated implants formed on the flocked surface 12a of the head portion 12 in which the toothbrush brush 1 is refracted in half at a substantially central portion, and a plurality of these are converged. Planted in pores. Here, for example, the brush bundle 11 is implanted into the flocked hole by, for example, inserting a retaining material called a flat wire between the toothbrush brush 1 folded in half and driving it into the flocked hole, or It can be performed by a method such as heat welding.

  The brush bundle 11 may have a configuration in which all the hair lengths of the toothbrush brushes 1 are aligned as shown in FIG. 4B, or may have a configuration in which the hair lengths are not uniform. In addition, as for the hair tip contour shape (hair cutting shape) of the brush bundle 11, as shown in the illustrated example, the tip of the brush bundle is pruned flat by so-called flat cutting. It can be made into the shape which pruned the front-end | tip to the unevenness | corrugation, and the shape which pruned the whole brush bundle in convex shape or concave shape with the predetermined curvature.

  The toothbrush in which the toothbrush brush 1 of the present embodiment is used is not limited to the shape of the toothbrush 10 illustrated in FIGS. 4A and 4B, and the shape and form thereof are not limited. About can be employ | adopted suitably. For example, like an electric toothbrush, it may be configured such that a head portion in which a brush bundle is implanted can be attached to and detached from the grip portion.

[Toothbrush brush]
As described above, the toothbrush brush according to the present invention includes the core portion 2 and the sheath portion 3 that covers the core portion 2 concentrically, and at least one end side is formed as a tapered portion 1a. Is made of a resin containing polybutylene terephthalate (PBT), and the sheath part 3 is made of a resin containing polyethylene terephthalate (PET), and the core part 2 is formed to be exposed from the sheath part 3 in the taper part 1a. In addition, a tapered shape is formed so as to be continuous with both the core portion 2 and the sheath portion 3. Further, the toothbrush brush 1 of the present embodiment has a core-sheath structure in which a sheath 3 is arranged around one core 2 as shown in FIG.
Further, as shown in the cross-sectional view of FIG. 1, the toothbrush brush 1 is formed with a smooth taper shape in the taper portion 1 a so as to be continuous with both the core portion 2 and the sheath portion 3. The portion 2 extends from the exposed position 2a toward the tip portion 1b.

The toothbrush brush 1 has the above-described core-sheath structure composed of the core portion 2 and the sheath portion 3, and the tapered portion 1 a formed over both the core portion 2 and the sheath portion 3. have. Further, the core part 2 which is the inner side of the brush is made of a resin containing PBT having a high elasticity and a softness of about 450 kg / mm ^2, and the sheath part 3 which is the outer side of the brush is made of an elastic modulus. It is composed of a resin containing PET having a high rigidity of about 1500 kg / mm ² .
When toothbrushing is performed with a toothbrush constructed using such a toothbrush brush 1, the toothbrush brush 1 can be easily moved between the teeth by the action of the tapered portion 1 a formed at the end of the brush. Moreover, since the front-end | tip part 1b (core part 2) consists of soft PBT, the irritation | stimulation with respect to a gingiva is suppressed small. Moreover, since the sheath part 3 consists of hard PET, the rigidity of the whole brush 1 for toothbrushes is improved, it has high bending recovery property, and can prevent the damage at the time of dentifrice. Moreover, taper shape is formed so that it may continue to both the core part 2 and the sheath part 3, and it is set as the smooth taper part 1a, and it prevents that peeling arises between the core part 2 and the sheath part 3 it can. Therefore, it is possible to construct a toothbrush that can provide both excellent scrubbing force and high durability, and can reduce pain during brushing.

Further, the toothbrush brush 1 of the present embodiment has the taper portions 1a as described above formed at both ends of the brush as shown in FIG. 3A, and the length of the brush as shown in FIG. The outer diameter D (outer shape of the toothbrush brush 1 as a whole) in the center in the length direction is in the range of 0.18 to 0.22 mm, and the outer diameter d in the tip portion 1b of the brush is in the range of 0.005 to 0.04 mm. From the exposed position 2a of the core portion 2 exposed from the sheath portion 3 in the taper portion 1a, the thickness t of the sheath portion 3 at the central portion in the longitudinal direction of the brush is in the range of 0.01 to 0.02 mm. It can be set as the structure made into the range whose length f to the front-end | tip 1b is 4-7 mm. In the example shown in FIG. 1, the outer shape D is 0.20 mm, the outer shape d is 0.02 mm, the thickness t is 0.02 mm, and the length f is 4 mm. In the example shown in FIG. 2, the outer shape D is 0.20 mm, the outer shape d is 0.02 mm, the thickness t is 0.01 mm, and the length f is 7 mm.
The toothbrush brush 1 according to the present embodiment can obtain the effects described below by defining the above-described dimensional ranges.

The outer diameter D (the outer shape of the entire toothbrush brush 1) at the central portion in the length direction of the toothbrush brush 1 is preferably in the range of 0.18 to 0.22 mm. When the outer shape D is within this range, higher interdental penetration and scrubbing force can be obtained, and stimulation to the gingiva can be suppressed.
If the outer diameter D is less than 0.18 mm, the scrubbing force decreases, which is not preferable. If it exceeds 0.22 mm, irritation to the gums increases, and the user may feel great pain when brushing his teeth.

The outer diameter d of the tip 1b of the toothbrush brush 1 is preferably in the range of 0.005 to 0.04 mm. When the outer shape d is within this range, higher interdental penetration and scrubbing force can be obtained, and stimulation to the gingiva can be suppressed.
It is difficult to process the outer shape d to 0.005 mm by a method other than the hydrolysis treatment using an alkaline solution, which will be described in detail later. Moreover, when the said external shape d exceeds 0.04 mm, irritation | stimulation with respect to a gum will become large and there exists a possibility that a user may feel big pain at the time of toothpaste.

It is preferable that the thickness t of the sheath part 3 in the longitudinal center part of the toothbrush brush 1 is in a range of 0.01 to 0.02 mm. When the thickness t is within this range, higher interdental penetration and scrubbing force can be obtained, and stimulation to the gingiva can be suppressed.
If the thickness t is less than 0.01 mm, the scrubbing force becomes weak, and if it exceeds 0.02 mm, the interdental penetration may be reduced.

In the tapered portion 1a of the toothbrush brush 1, the length f of the core portion 2 exposed from the sheath portion 3 from the exposed position 2a to the tip 1b is preferably in the range of 4 to 7 mm. When the length f is within this range, higher interdental penetration and scrubbing force can be obtained, and stimulation to the gingiva can be suppressed.
If the length f is less than 4 mm, the interdental penetration is reduced, and if it exceeds 7 mm, the scrubbing force may be reduced.

Further, when the toothbrush 10 as shown in FIGS. 4A and 4B is configured using the toothbrush brush 1 (brush bundle 11), the tip of the brush bundle 11 from the flocked surface 12a of the head portion 12 ( The brush length L to the tip 1b) is preferably in the range of 9 to 13 mm, more preferably in the range of 10 to 12 mm.
When the brush length L is less than 9 mm, interproximal penetration is degraded, and when it exceeds 13 mm, the operability of the toothbrush 10 in the oral cavity may be degraded.

  According to the toothbrush brush 1 of the present embodiment as described above, at least one end side is formed as the tapered portion 1a, and the core portion 2 is made of a resin containing soft (low rigidity) polybutylene terephthalate (PBT). In addition, the sheath 3 is made of a resin containing hard (high rigidity) polyethylene terephthalate (PET), and in the tapered portion 1a, the core 2 is exposed from the sheath 3, and the core 2 and Since it is set as the structure by which the taper shape was formed so that it might continue to both of the sheath parts 3, while having high interdental penetration property and intensity | strength, irritation | stimulation to a gingiva can be suppressed. Thus, when a toothbrush is formed using the toothbrush brush 1 of the present embodiment, the tooth has both excellent scrubbing force and durability, and can reduce pain during use. A brush 10 is obtained.

Further, the toothbrush brush 1 of the present embodiment has a taper portion 1a with the core portion 2 and the sheath portion 3 as the core-sheath structure of the above material, and then the outer diameter D and the brush at the central portion in the longitudinal direction of the brush. The outer diameter d of the tip 1b, the thickness t of the sheath 3 at the center in the longitudinal direction of the brush, and the length of the core 2 exposed from the sheath 3 in the taper 1a from the exposed position 2a to the tip 1b By optimizing each dimension of f, the brushing force is higher, the interdental penetration is excellent, irritation to the gingiva is suppressed, and the durability is also excellent.
Therefore, by configuring the toothbrush using the toothbrush brush 1, it is possible to obtain the toothbrush 10 in which both excellent scrubbing force and durability are obtained and pain during use is reduced.

  The toothbrush brush according to the present invention is particularly made of a material containing a soft PBT with a core portion on the inner side of the brush, and a sheath portion on the outer side made of a material containing a hard PET, and a tapered portion. In the above, the core portion is formed so as to be exposed from the sheath portion, and both the core portion and the sheath portion are formed in a tapered shape. Durability and pain reduction effect can be obtained.

  As an example of the toothbrush using the toothbrush brush according to the present invention, the toothbrush 10 shown in FIGS. 4 (a) and 4 (b) has been described. However, the brush bundle 11 composed of the toothbrush brush 1 is used as a head. When planting on the flocked surface 12a of the part 12, all the brushes on the flocked surface 12a may be constituted by the brush bundle 11 comprising the toothbrush brush 1 having a core-sheath structure according to the present invention, or On the flocked surface 12a, both the toothbrush brush according to the present invention and the filament (brush) having a single structure may be implanted.

[Method for producing toothbrush brush]
The method for producing a toothbrush brush according to the present invention is a method of forming a core portion 2 and a sheath portion 3 that covers the core portion 2 concentrically, and forming at least one end side as a tapered portion 1a. The core part 2 is a resin containing polybutylene terephthalate (PBT), the sheath part 3 is a resin containing polyethylene terephthalate (PET), the taper part 1a is formed by dissolution treatment with an alkaline solution, and the core part 2 is formed. In this method, the taper portion 1 a is exposed from the sheath portion 3, and a tapered shape is formed so as to be continuous with both the core portion 2 and the sheath portion 3.

  First, the core part 2 and the sheath part 3 covering the core part 2 concentrically are formed into a filament (brush) having a core-sheath structure by a conventionally known method. And this filament is immersed in an alkaline solution, for example, an alkaline hydrolysis treatment agent. At this time, both the sheath portion 3 made of resin containing PET and the core portion 2 made of resin containing PBT are gradually dissolved from the end portion, so as shown in FIG. 1 (and also see FIG. 2). The smooth taper portion 1a can be formed at the filament end. Here, as a method of immersing the filament in the alkaline solution, a conventionally known immersing method can be employed.

  According to the method for manufacturing a brush for a toothbrush of the present invention, since the core portion 2 and the sheath portion 3 have a core-sheath structure made of the above-described material, and this filament (brush) is immersed in an alkaline solution, the end portion of the filament Can be easily dissolved, and a brush for a toothbrush provided with the tapered portion having the above-described configuration can be easily manufactured with simple equipment. Thereby, it becomes possible to suppress an increase in the manufacturing cost of the toothbrush brush and the toothbrush using the same.

  Hereinafter, examples for demonstrating the brush for toothbrush of the present invention and the toothbrush using the same will be described, but the present invention is not limited to this example.

[Production of toothbrush brush and toothbrush]
A toothbrush brush as shown in FIGS. 1 to 3 and a toothbrush sample as shown in FIG. 4 were prepared by the following procedure.

(Preparation of toothbrush brush)
First, a core portion 2 made of polybutylene terephthalate (PBT) and a sheath portion 3 made of polyethylene terephthalate (PET) and covering the core portion 2 concentrically with a filament having a core-sheath structure by a conventionally known method ( A brush).
Then, the filament is cut into a predetermined length and immersed in an alkaline hydrolysis treatment agent by a conventionally known method to dissolve both ends of the filament to form a tapered portion 1a as shown in FIG. A toothbrush brush according to the present invention was prepared.

(Production of toothbrush)
Next, the brush 1 for toothbrushes obtained by the above procedure was refracted in half at a substantially central portion, and a plurality of these were converged to form a brush bundle 11.
And this brush bundle 11 is made into the state which pinched | interposed the flat line between the brush 1 for toothbrush folded in half, and on the flocking surface 12a of the head part 12 as shown to Fig.4 (a), (b). It was driven into a not-shown flock hole formed. Here, a flocked hole having a diameter of 1.5 mm is formed on the flocked surface 12a of the head portion 12, and the hole arrangement and the number of holes are “3” + “4 × 6” along the toothbrush length direction. ”+“ 3 ”= 30, the row pitch (toothbrush length direction) is 2.5 mm, and the column pitch (toothbrush width direction) is 2.2 mm.
The toothbrush 10 as shown to Fig.4 (a) was produced according to the above procedures.

  For the above-described toothbrush brush and toothbrush, the outer diameter D at the central portion in the length direction of the brush, the outer diameter d at the tip portion 1b of the brush, and the thickness t of the sheath portion 3 at the central portion in the length direction of the brush. In the taper portion 1a, the length of the core portion 2 exposed from the sheath portion 3 from the exposed position 2a to the tip 1b is set as the dimensions shown in Table 1 below. A brush for a brush and a toothbrush were prepared. Further, the toothbrushes of Comparative Examples 1 to 11 were made in the same procedure as described above except that the structure and material of the brush for toothbrush were configured as shown in Table 1 below, and the above dimensions were set to the values shown in Table 1 below. Brushes and toothbrushes were prepared. Here, FIG. 1 (toothbrush brush 1) is a diagram showing a toothbrush brush in which each of the above dimensions is the value shown in Example 4, and FIG. 2 (toothbrush brush 21) is It is a figure which shows the brush for toothbrush in which each dimension was made into the dimension value shown in Example 3. FIG.

[Evaluation methods]
Using the samples of each Example and Comparative Example obtained as described above, each item of scrubbing force, interdental penetration, and irritation to gingiva was evaluated by the following method.

(Rubbing force)
For each toothbrush brush sample, the bending force of the brush is measured by a bristle hardness test specified in ISO8627, and the scrubbing force is determined according to the following three-stage criteria. The results are shown in Table 2 below.
(1) ○: The bending force of the brush was 6 cN / mm ² or more.
(2) Δ: The bending force of the brush was 5 cN / mm ² or more and less than 6 cN / mm ² .
(3) x: The bending force of the brush was less than 5 cN / mm ² .

(Interdental penetration)
About each sample of the above-mentioned toothbrush brush, using a scrubber tester (manufactured by Lion Corporation), the degree of penetration of the bristles in the interdental interdental model was measured under a scrub condition of load: 250 g, stroke: 30 mm. The interproximal penetration was determined according to the following three-stage criteria, and the results are shown in Table 2 below.
(1) ○: The degree of penetration between the teeth was 60% or more.
(2) Δ: The degree of penetration between the teeth was 50% or more and less than 60%.
(3) x: The degree of penetration between the teeth was less than 50%.

(Gum stimulation)
For each sample of the above-mentioned toothbrush, the number of users (panelists) is n = 10 (persons), each panelist performs a brushing operation, and irritation to the gingiva (gum pain) as shown below. The results are shown in Table 2 below.
(1) ○: The gum pain was hardly felt.
(2) Δ: I felt a slight pain in my gums.
(3) X: I felt a lot of gum pain.

  From the results shown in Table 2, the toothbrush brushes of Examples 1 to 8 having the structures and materials defined in the present invention and having the dimensional values defined in the present invention have excellent scrubbing power. The toothbrush that has interdental penetration and uses the brushes for toothbrushes of Examples 1 to 8 has less pain that the user feels in the gums and suppresses irritation to the gingiva. It is clear.

On the other hand, in the toothbrush brushes of Comparative Examples 1 and 2, the outer diameter D at the central portion in the longitudinal direction of the brush was below the specified range of the present invention, resulting in poor scrubbing force.
Further, in the toothbrush brush of Comparative Example 3, the thickness t of the sheath portion in the central portion in the longitudinal direction of the brush exceeds the specified range of the present invention, and the scrubbing force is inferior. Toothbrushes using the gingiva stimulated the gums.
Further, in the toothbrush brush of Comparative Example 4, the thickness t of the sheath portion at the central portion in the longitudinal direction of the brush is less than the specified range of the present invention, and the interdental penetration is greatly inferior. The toothbrushes using the brushes used for the brushes were greatly stimulated by the gums.

Further, in the toothbrush brush of Comparative Example 5, the outer diameter d at the tip of the brush exceeds the specified range of the present invention, the interdental penetration is inferior, and the toothbrush using this toothbrush brush. The gingival irritation was considerably greater.
Further, in the brushes for toothbrushes of Comparative Examples 6 and 7, the outer diameter D at the central portion in the longitudinal direction of the brush exceeds the specified range of the present invention, and the interdental penetration is inferior. Toothbrushes using the gingiva stimulated the gums considerably.

Further, the toothbrush brush of Comparative Example 8 has a structure in which the core portion is made of hard PET and the sheath portion is made of soft PBT, so that the interdental penetration is greatly inferior, and this toothbrush brush is used. Toothbrushes were significantly more irritating to the gums.
In addition, the toothbrush brush of Comparative Example 9 had a structure in which the core part was made of hard PTT and the sheath part was made of soft PBT, so that the strength was very low and the scrubbing force was greatly inferior.

Moreover, since the brush for toothbrushes of the comparative example 10 is a filament of a single structure made of PBT, the scrubbing force was greatly inferior.
Further, the toothbrush brush of Comparative Example 10 is a filament having a single structure made of PBT, and the outer diameter D in the central portion in the longitudinal direction of the brush exceeds the specified range of the present invention. Toothbrushes using toothbrush brushes were significantly stimulated to the gums.

  From the above results, it has been clarified that the toothbrush and toothbrush of the present invention can provide both excellent scrubbing force and durability, and can reduce pain during use.

It is the schematic which shows an example of the brush for toothbrushes concerning this invention, and is sectional drawing explaining a brush structure. It is the schematic which shows the other example of the brush for toothbrushes concerning this invention, and is sectional drawing explaining a brush structure. It is the schematic which shows an example of the brush for toothbrushes based on this invention, (a) is a partially broken top view, (b) is sectional drawing. It is the schematic which shows an example of the toothbrush which concerns on this invention, (a) is a top view explaining the whole, (b) is the elements on larger scale explaining a head part.

Explanation of symbols

1, 21 ... brush for toothbrush, 1a ... taper part, 1b, 21b ... tip part, 2, 22 ... core part, 2a, 22a ... exposed position, 3, 23 ... sheath part, 10 ... toothbrush, 11 ... brush Bundle, 12 ... head part, 12a ... flocked surface, 13 ... gripping part, 14 ... neck part

Claims (4)

A toothbrush brush comprising a core part and a sheath part concentrically covering the core part, wherein at least one end side is formed as a taper part,
The core part is made of a resin containing polybutylene terephthalate (PBT), and the sheath part is made of a resin containing polyethylene terephthalate (PET),
In the taper portion, the core portion is formed so as to be exposed from the sheath portion, and a tapered shape is formed so as to be continuous with both the core portion and the sheath portion. Brush for use. The toothbrush brush according to claim 1,
The tapered portion is formed at both ends of the brush,
The outer diameter of the brush in the longitudinal center is in the range of 0.18 to 0.22 mm,
The outer diameter at the tip of the brush is in the range of 0.005 to 0.04 mm,
The thickness of the sheath at the central portion in the longitudinal direction of the brush is in the range of 0.01 to 0.02 mm,
The toothbrush brush, wherein the length of the core portion exposed from the sheath portion in the tapered portion is from 4 to 7 mm from the exposed position to the tip portion.   The toothbrush according to claim 2, wherein the brush for toothbrush is refracted in half at a substantially central portion, and a plurality of bundles of brushes in which the brush is bundled are implanted. Forming a core part and a sheath part concentrically covering the core part, and forming a brush for a toothbrush, wherein at least one end side is formed as a tapered part;
The core part is a resin containing polybutylene terephthalate (PBT), and the sheath part is a resin containing polyethylene terephthalate (PET),
The taper portion is formed by a dissolution treatment with an alkaline solution, the core portion is exposed from the sheath portion in the taper portion, and a tapered shape is formed so as to be continuous with both the core portion and the sheath portion. A method for producing a toothbrush brush.

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