JP2022083301A - Toothbrush and production method of toothbrush - Google Patents

Abstract

To provide a toothbrush capable of efficiently removing dental plaque in a whole oral cavity for improving cleaning property.SOLUTION: There is provided a toothbrush in which, a bristle bundle formed of a plurality of brush bristles 10 is fixed to each of a plurality of implantation holes which is formed on an implantation surface of a head part. The brush bristle 10 has a taper part 21 whose radial width gradually decreases as approaching a tip end, the taper part 21 is configured so that: a width in a radial cross section L3 on a position separated from the tip end of the brush bristle 10 by 1.0 mm is 25% or more and 55% or less of a radial width L5 of the filament forming the brush bristle 10, a width L4 in a radial cross section on a position separated from the tip end of the brush bristle 10 by 2.0 mm is 50% or more and 90% or less of a radial width L5 of the filament forming the brush bristle 10, and a surface of the taper part 21 has a fine irregular part formed by mechanical rough surface processing.SELECTED DRAWING: Figure 2

Description

The present invention relates to a toothbrush and a method for manufacturing a toothbrush.

The main purpose of the toothbrush is to clean the surface of teeth and gums, and to clean the space between teeth and the cervical region. Therefore, it has been possible to efficiently remove plaque by efficiently performing appropriate cleaning according to the type of teeth such as front teeth and back teeth and the tooth parts such as interdental teeth, tooth surface, and cervical region. , The material, tip shape, thickness, etc. of the brush bristles, the arrangement of the bristles, the number of constituents, etc. have been devised in various ways. For example, a tapered portion is formed at the tip of the brush bristles so that the width in the radial direction gradually decreases toward the tip, making it easier for the brush bristles to enter areas where the brush bristles are difficult to reach, such as between teeth and the gingival margin. As a result, those with improved cleanability are known. Patent Document 1 describes a toothbrush having improved cleanability by chemically treating the tip of a filament to form a tapered portion at the tip and improving the ability of brush bristles to enter gaps between teeth and the like. Has been done.

Japanese Unexamined Patent Publication No. 2004-313365

However, although the reachability of the brush bristles to the interdental space and the gingival marginal portion is improved by forming the tapered portion, the bristles may be weakened due to the decrease in the rigidity of the brush bristles. As a result, not only the cleanability on the tooth surface is deteriorated, but also the cleanability on the interdental space, the cervical region and the like is not satisfactory.

In order to solve the above problems, the toothbrush of the present invention is a toothbrush in which a hair bundle composed of a plurality of brush bristles is fixed to each of a plurality of bristles formed on the bristles surface of the head portion. The bristles have a tapered portion whose radial width gradually decreases toward the tip, and the tapered portion has a radial cross-sectional width at a position 1.0 mm from the tip of the brush bristles. 25% or more and 55% or less of the radial width of the filament to be formed, and the width of the radial cross section at a position 2.0 mm from the tip of the brush bristles is the radial width of the filament forming the brush bristles. It is 50% or more and 90% or less, and a fine uneven portion is formed on the surface of the tapered portion by a mechanical roughening treatment.

According to the above configuration, since the tapered portion is formed at the tip of the brush bristles, the brush bristles can easily reach the portion where the brush bristles are difficult to reach, such as between the teeth and the gingival margin. Further, since the fine uneven portion is formed on the surface of the tapered portion, the fine uneven portion acts to entangle and catch the plaque and scrape it out, so that the plaque can be efficiently removed. Cleanability is improved not only for the interdental space and the gingival margin, but also for the tooth surface and the cervical region.

In the above configuration, it is preferable that the surface of the tapered portion has an average value of line roughness Ra of 0.4 μm or more and 0.9 μm or less in the range of 1.0 mm to 1.1 mm from the tip of the brush bristles. ..

In the above configuration, it is preferable that the surface of the tapered portion has an average value of line roughness Ra of 0.5 μm or more and 1.0 μm or less in the range of 2.0 mm to 2.1 mm from the tip of the brush bristles. ..

According to the above configuration, the surface of the tapered portion is roughened by the fine uneven portion formed on the surface of the tapered portion, whereby plaque in the oral cavity can be effectively removed.

In order to solve the above problems, the method for manufacturing a toothbrush of the present invention is a method for manufacturing a toothbrush in which a hair bundle composed of a plurality of brush bristles is fixed to each of a plurality of bristles formed on the flocked surface of the head portion. The chemical treatment step of chemically treating the filament to form the brush bristles having a tapered portion whose radial width gradually decreases toward the tip, and the bristles formed by bundling a plurality of the brush bristles. The hair transplantation step of fixing the bundle to each of the plurality of hair transplantation holes and the roughening treatment step of mechanically roughening the surface of the fixed hair bundle are provided.

According to the above configuration, a tapered portion is formed at the tip of the brush bristles by a chemical treatment, and the surface of the tapered portion can be made rough by a roughening treatment step. Therefore, it is possible to manufacture a toothbrush having good crevice entry property based on the tapered shape and good plaque removing property based on the surface condition of the tapered portion.

According to the toothbrush of the present invention and the method for producing the same, a toothbrush having excellent cleanability can be obtained by effectively removing plaque in the entire oral cavity.

It is a schematic view of the head part of the toothbrush of this embodiment, (a) is the side view of the head part, (b) is the top view of the head part. (A) is a partially enlarged view of the brush bristles, and (b) is a partially enlarged view of the tapered portion of the brush bristles. The figure which shows the result of the evaluation test 1 of the cleanability. (A) and (b) are diagrams showing images of the results of the cleanability evaluation test 2.

Hereinafter, an embodiment in which the toothbrush of the present invention is embodied will be described.
As shown in FIGS. 1A and 1B, a plurality of flocking holes 3 are formed on the flocking surface 2a of the head portion 2 of the toothbrush 1. The number, shape, and arrangement of the flocked holes 3 can be arbitrarily selected. In the toothbrush 1 of the present embodiment, 41 flocking holes 3 are formed.

As shown in FIG. 1A, a hair bundle 4 composed of a plurality of brush hairs 10 is fixed in each hair-planting hole 3. The number of brush bristles 10 constituting one bristles 4 is not particularly limited. For example, it can be about 10 to 20 pieces. Further, as a method of fixing the hair bundle 4, for example, a method of folding a plurality of brush hairs 10 in half and inserting them into the hair-planting hole 3 together with a metal flat wire can be mentioned.

As shown in FIG. 1A, the tip of the hair bundle 4 fixed to each flocked hole 3 is substantially parallel to the flocked surface 2a of the head portion 2 when the head portion 2 is viewed from the side. .. The protruding length H1 from the flocked surface 2a of the hair bundle 4 is preferably about 8.0 mm or more and 14.0 mm or less, and more preferably about 9.0 mm or more and 13.0 mm or less.

The material of the filament constituting the brush bristles 10 is not particularly limited, and conventionally known synthetic resin materials can be used. Examples of the synthetic resin material include polyamides such as nylon 610 and nylon 612, polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polyester such as polybutylene naphthalate, polyolefins such as polypropylene, and olefin elastomers. Examples thereof include styrene-based elastomers. The synthetic resin material may be used alone or in combination of two or more.

The hardness of the filaments constituting the brush bristles 10 can be appropriately set. The hardness of the brush bristles 10 may be constant in each bristles 3, or the hardness of the brush bristles 10 may be changed in some of the flocking holes 3. For example, as shown by the black circle flocking hole 3 in FIG. 1 (b), a brush bristles 10 having a normal hardness are used for the outer edge portion of the head portion 2, and the white circle flocking hole 3 is shown in FIG. 1 (b). As described above, it is possible to use a stiff brush bristles 10 in the central portion of the head portion 2.

The radial cross-sectional shape of the filament constituting the brush bristles 10 can be appropriately set. The cross-sectional shape in the radial direction may be a circular shape, a semi-circular shape, an elliptical shape, or a polygon such as a triangle or a quadrangle. Alternatively, it may be a variant such as an amorphous shape. Further, the filament may be one that extends straight in the axial direction, or may be a spiral hair that is twisted in the axial direction. Further, the hair bundles 4 fixed to all the hair-implanted holes 3 may be composed of filaments having the same cross-sectional shape, or filaments having different cross-sectional shapes may be mixed. The cross-sectional shape of the filament may be different in the flocked holes 3.

Next, the shape of the tip of the brush bristles 10 constituting the bristles 4 fixed to the flocking holes 3 will be described together with their actions.
As shown in FIG. 2A, a sharpened tapered portion 21 is formed at the tip of the brush bristles 10 so that the width in the radial direction gradually decreases toward the tip. The axial length H2 of the tapered portion 21 is preferably about 1.0 mm to 5.0 mm, more preferably about 2.0 mm to 4.0 mm. When the tapered portion 21 is formed in this range, the brush bristles 10 have good reachability to the interdental space, the gingival marginal portion, and the like, and the plaque removing property for these portions is improved. The "axial length H2 of the tapered portion 21" refers to the distance from the 80% point of the "filamental width L5 of the filament" to be described later to the tip of the brush bristles 10. That is, the "tapered portion 21" refers to a portion in the range from the tip of the filament to the point where the radial width L5 of the filament is 80%.

As shown in FIGS. 2A and 2B, the radial width L1 at the portion 0.1 mm from the tip of the brush bristles 10 in the tapered portion 21 is the radial direction at the base end portion of the brush bristles 10. The width L5 is preferably in the range of 3% or more and 15% or less, and more preferably in the range of 4% or more and 11% or less. The radial width L2 at the portion 0.5 mm from the tip of the brush bristles 10 in the tapered portion 21 shall be in the range of 14% or more and 33% or less of the radial width L5 at the base end portion of the brush bristles 10. Is preferable, and more preferably in the range of 18% or more and 27% or less. The radial width L3 at the portion 1.0 mm from the tip of the brush bristles 10 in the tapered portion 21 shall be in the range of 25% or more and 55% or less of the radial width L5 at the base end portion of the brush bristles 10. Is preferable, and more preferably in the range of 30% or more and 46% or less. The radial width L4 at the portion 2.0 mm from the tip of the brush bristles 10 in the tapered portion 21 shall be in the range of 50% or more and 90% or less of the radial width L5 at the base end portion of the brush bristles 10. Is preferable, and more preferably in the range of 57% or more and 80% or less.

The radial width means "the length of a line segment passing through the center of the radial cross section of the brush bristles 10." For example, when the radial cross-sectional shape is circular, the radial width corresponds to the diameter, and when the radial cross-sectional shape is rectangular, the radial width corresponds to the diagonal line. Further, the radial width L5 at the base end portion of the brush bristles 10 is equal to the radial width of the filament constituting the brush bristles 10.

A fine uneven portion (not shown) is formed on the surface of the tapered portion 21. The fine uneven portion is formed by mechanically roughening the surface of the tapered portion 21 using a grinder or the like to which a grindstone is attached.

The fine uneven portion is formed from the tip of the tapered portion 21. The fine uneven portion may be formed over the entire length of the tapered portion 21, but it does not necessarily have to be formed over the entire length of the tapered portion 21. The fine uneven portion is formed in the roughening treatment step described later, and the forming range is adjusted by the grind depth in the roughening treatment step. The fine uneven portion may be formed in a range of approximately 7.0 mm from the tip of the tapered portion 21, and it is preferable that the fine uneven portion is formed in such a range from the viewpoint of efficient plaque removal.

Since the fine uneven portion is formed, the line roughness Ra on the surface of the tapered portion 21 becomes larger than the line roughness Ra on the surface of the filament. Here, the line roughness Ra on the surface of the tapered portion 21 can be obtained as an arithmetic line roughness Ra by measuring a predetermined region on the surface of the roughened brush bristles 10 with a laser microscope. Then, the maximum value and the minimum value are obtained from the obtained measured values of the arithmetic line roughness Ra, and the average value is calculated.

The average value of the line roughness Ra on the surface of the tapered portion 21 is preferably 0.4 μm or more and 0.9 μm or less, preferably 0.6 μm or more, in the range of 1.0 mm to 1.1 mm from the tip of the brush bristles 10. It is more preferably 0.7 μm or less. Further, in the range of 2.0 mm to 2.1 mm from the tip of the brush bristles 10, it is preferably 0.5 μm or more and 1.0 μm or less, and more preferably 0.7 μm or more and 0.8 μm or less. Since the fine uneven portion is formed on the surface of the tapered portion 21 so that the line roughness Ra is in this range, the plaque remaining in the oral cavity is efficiently scraped off to the surface of the tapered portion 21. It becomes a state of being entangled and caught, and the plaque removal property is improved.

Next, a method for manufacturing the toothbrush 1 will be described.
The method for manufacturing the toothbrush 1 is a chemical treatment step of chemically treating a filament to form a brush bristles 10, a flocking step of fixing a bristles 4 composed of a plurality of brush bristles 10 to a flocking hole 3, and a tip portion of the bristles 4. It is provided with a roughening treatment step of performing treatment with a roughening jig.

In the chemical treatment step, the tip of the filament is chemically treated to form a sharpened tapered portion 21 whose radial width gradually decreases toward the tip. The chemical treatment can be carried out by a conventionally known method, and the treatment time, treatment temperature and the like can be appropriately adjusted. By the chemical treatment, a brush bristles 10 having a tapered portion 21 having a tapered portion 21 whose width in the radial direction gradually decreases toward the tip is formed so that the widths L1, L2, L3, and L4 are in the above range.

In the hair transplanting step, a plurality of brush hairs 10 are bundled to form a hair bundle 4, and each hair bundle 4 is fixed to a hair transplant hole 3 formed on the hair transplant surface 2a of the head portion 2. The method of fixing the hair bundle 4 can be performed by a conventionally known method. For example, a method of folding a plurality of brush hairs 10 in half and inserting them into the hair-planting hole 3 together with a metal flat wire can be mentioned.

Subsequently, the toothbrush 1 to which the bristles 4 are fixed is fixed in the vicinity of the roughening jig, and the tip portion of the brush bristles 10 of the bristles 4 is roughened by the roughening jig. Examples of the roughening jig include a grinder to which a disc-shaped grindstone is attached. By rotating the grinder, the tip portion of the brush bristles 10 of the bristles 4 is physically roughened, and fine uneven portions are formed on the surface of the tapered portion 21.

The roughening treatment is performed so that the grindstone hits the surface of the tapered portion 21 from the tip of the brush bristles 10 to a predetermined depth. The depth at which the grindstone from the tip of the brush bristles 10 hits, that is, the grind depth by the grindstone can be appropriately adjusted. It should be noted that the setting depth at which the grindstone is applied does not always match the grind depth. Further, even if the setting depth at which the grindstone is applied is constant, the grind depth of each brush bristles 10 may fluctuate by, for example, about ± 0.5 mm. This is because the tip of the brush bristles 10 bends during the roughening treatment. The bending method of the brush bristles 10 also differs depending on the material of the filament constituting the brush bristles 10, the radial width L5, and the like.

In this way, the toothbrush 1 is obtained through each step.
Next, the effect of the toothbrush 1 of the present embodiment will be described.
(1) In the toothbrush 1 of the present embodiment, brush bristles 10 having a tapered portion 21 whose width in the radial direction gradually decreases toward the tip are transplanted. In the tapered portion 21, the width L3 of the radial cross section at a position 1.0 mm from the tip of the brush bristles 10 is 25% or more and 55% or less of the radial width L5 of the filament, and 2. The width L4 of the radial cross section at the position of 0 mm is 50% or more and 90% or less of the radial width L5 of the filament. Then, a fine uneven portion is formed on the surface of the tapered portion 21 by a mechanical roughening treatment.

Therefore, not only is it easy for the brush bristles to reach areas where the brush bristles are difficult to reach, such as between the teeth and the gingival margin, but also the fine uneven parts act to entangle and scoop out the plaque, making the plaque more efficient. Can be removed. Cleanability is improved not only for the interdental space and the gingival margin, but also for the tooth surface and the cervical region.

(2) The tapered portion 21 has an average value of line roughness Ra on the surface in the range of 1.0 mm to 1.1 mm from the tip of the brush bristles 10 of 0.4 μm or more and 0.9 μm or less, and the tip of the brush bristles 21. The average value of the line roughness Ra on the surface in the range of 2.0 mm to 2.1 mm is 0.5 μm or more and 1.0 μm or less.

Therefore, the effect of entwining and scraping out dental plaque due to the fine uneven portion is good.
(3) In the toothbrush 1 of the present embodiment, the chemical treatment step of chemically treating the tip of the filament to form the tapered portion 21 and the surface of the brush bristles 10 of the bristles 4 fixed to the bristles 3 are mechanically treated. Manufactured through a roughening treatment step.

Therefore, a sharply shaped tapered portion 21 can be formed at the tip of the brush bristles 10 by chemical treatment, and the brush bristles 10 having excellent gap penetration can be obtained. Further, the surface of the tapered portion 21 can be made rough by the roughening treatment step, and the brush bristles 10 can be easily entangled and scraped out of plaque. It is possible to manufacture a toothbrush 1 having good gap entry property based on the tapered shape and good plaque removing property based on the surface condition of the tapered portion 21.

The above embodiment can be modified as follows. The above embodiment and the following modified examples can be applied in combination with each other within a technically consistent range.
-In the above embodiment, the tip of the hair bundle 4 fixed to all the flocked holes 3 has been described as a toothbrush 1 that is substantially parallel to the flocked surface 2a, but the tip shape of the hair bundle 4 is the same. Not limited. When a row of hair bundles 4 fixed to a plurality of hair-planting holes 3 connected in the lateral direction is used as a hair bundle row, the hair bundle rows are adjacent to each other in the longitudinal direction, and the tip of the hair bundle is formed into a mountain shape as a whole. The portions may be formed. For example, the hair bundle 4 fixed to the hair-planting holes 3 formed in the second and third rows from the tip side of the head portion 2 has a mountain shape having the position where the hair bundles 4 in the second row face each other as the top. By forming it, a mountain cutting portion may be formed. By forming the mountain cutting portion, it is possible to improve the accessibility to the gap between the teeth and the gingival margin.

In FIG. 2, the tapered portion 21 is shown as having a shape symmetrical with respect to the central axis of the filament, but the shape of the tapered portion 21 is not limited to this. For example, it may be asymmetric with respect to the central axis of the filament, and the tip of the tapered portion 21 may be located at a position deviated from the central axis of the filament. That is, when the filament is viewed from above, the apex of the mountain does not have to be the center. More specifically, the radial width L3 of the brush bristles 10 in the tapered portion 21 is 25% or more and 55% or less of the radial width L5 of the filament, and the radial width L4 is the radial width L5 of the filament. If it is 50% or more and 90% or less of, both symmetric and asymmetric with respect to the central axis are included.

The fine uneven portion may not be formed at the tip of the brush bristles 10 at a position symmetrical with respect to the axial direction of the brush bristles 10, or may be formed at a position asymmetrical.
-It is not necessary that the tapered portion 21 having the above shape is formed at the tip portions of all the brush bristles 10 forming the bristles 4. Brush bristles 10 having tapered portions 21 whose widths L1, L2, L3, and L4 deviate from the above range may be mixed. Further, not only the brush bristles 10 having the tapered portion 21 but also the brush bristles 10 having a tip portion having a shape other than the tapered portion 21 may be mixed.

-The roughening process does not have to be performed by a grinder to which a grindstone is attached. Anything can be used as long as the surface of the brush bristles 10 can be made rough by mechanical treatment.

The toothbrush of the present invention will be described in more detail based on the following examples. The present invention is not limited to the configuration described in the Example column.
<Specification of the shape of the tapered portion 21>
A plurality of prototypes having different shapes and hardnesses of the brush bristles 10 were created, and the shape and dimensions of the tapered portion 21 were specified.

(Prototype 1)
In the flocked hole 3 formed in the flocked surface 2a of the head portion 2 having the shape shown in FIG. 1 (b), a hair bundle made of polybutylene terephthalate and having a circular cross-sectional shape in the radial direction is folded in half. It was inserted and a flat wire was fitted and fixed. As the brush bristles 10, those having a width (diameter) of 0.170 mm and having a tapered portion 21 formed by chemically treating the tip thereof were used. The number of brush bristles 10 filled in each bristles 3 was 20 to 29. The protrusion length H1 of the brush bristles 10 from the flocked surface 2a was set to about 11.0 mm.

After that, a grindstone attached to a grinder was applied to the tip of the brush bristles 10 to mechanically roughen the surface of the tapered portion 21 to form fine uneven portions. The grind depth was about 2.9 mm from the tip of the hair bundle. The toothbrush 1 created in this way was designated as prototype 1.

(Prototype 2)
It was created in the same manner as in Prototype 1 except that the grind depth was about 4.6 mm from the tip of the hair bundle.

(Prototype 3)
It was created in the same manner as in Prototype 1 except that the brush bristles 10 were not roughened.

(Prototype 4)
As the brush bristles 10, a brush bristles 10 having a width (diameter) of 0.150 mm and a filling number of 26 to 36, and having a tapered portion 21 formed by chemically treating the tip thereof, were used. It was created in the same manner as the prototype 1 except that the roughening treatment was not performed on the surface.

(Prototype 5)
As the brush bristles 10, a brush bristles 10 having a width (diameter) of 0.180 mm and a filling number of 18 to 26, and having a tapered portion 21 formed by chemically treating the tip, were used. It was created in the same manner as the prototype 1 except that the roughening treatment was not performed on the surface.

(Dimension measurement of taper portion 21)
The dimensions of the tapered portion 21 were measured for prototypes 1, 3 to 5. The dimensions were measured using a microscope (trade name VHX-6000, manufactured by KEYENCE CORPORATION) about 30 times for each prototype. In the dimensional measurement, the radial widths (diameters) L3 and L4 of the brush bristles 10 were measured at positions 1.0 mm and 2.0 mm from the tip of the tapered portion 21, respectively. The maximum, minimum, mean, and standard deviation (SD) of the measured values in each prototype were calculated as a ratio (%) to the radial width (diameter) L5 of the filament forming the brush bristles 10. The results are shown in Table 1.

表１の試作品１、３の結果より、グラインダーに取り付けられた砥石による粗面化処理の有無に関わらず、テーパー部２１の形状は同等であった。具体的には、テーパー部２１に粗面化処理を施した試作品１、粗面化処理を施していない試作品３のいずれにおいても、テーパー部２１の先端から１．０ｍｍの位置での直径は、フィラメントの直径の２５％以上５５％以下であった。また、テーパー部２１の先端から２．０ｍｍの位置での直径は、フィラメントの直径の５０％以上９０％以下であった。さらに、粗面化処理の有無に関わらず、テーパー部２１の先端から１．０ｍｍの位置での直径の平均値は、フィラメントの直径の３７．０～３９．０％であり、テーパー部２１の先端から２．０ｍｍの位置での直径の平均値は、フィラメントの直径の６３．０～６９．０％であった。

From the results of prototypes 1 and 3 in Table 1, the shape of the tapered portion 21 was the same regardless of the presence or absence of roughening treatment by the grindstone attached to the grinder. Specifically, in both the prototype 1 in which the tapered portion 21 has been roughened and the prototype 3 in which the tapered portion 21 has not been roughened, the diameter at a position 1.0 mm from the tip of the tapered portion 21. Was 25% or more and 55% or less of the diameter of the filament. The diameter at a position 2.0 mm from the tip of the tapered portion 21 was 50% or more and 90% or less of the diameter of the filament. Further, regardless of the presence or absence of the roughening treatment, the average value of the diameter at the position 1.0 mm from the tip of the tapered portion 21 is 37.0 to 39.0% of the diameter of the filament, and the tapered portion 21 has a diameter of 37.0 to 39.0%. The average value of the diameter at the position of 2.0 mm from the tip was 63.0 to 69.0% of the diameter of the filament.

Even in the prototypes 4 and 5 having different filament diameters, the shape of the tapered portion 21 was the same as that of the prototypes 1 and 3. Further, from the results of the prototypes 1 and 3, since the shape of the tapered portion 21 is the same due to the roughening treatment, the prototypes 4 in which the brush bristles 10 having different filament diameters are roughened. It can be said that the shape of the tapered portion 21 of No. 5 is the same regardless of the presence or absence of the roughening treatment.

(Measurement of line roughness Ra of taper portion 21)
In the tapered portion 21 in which the fine uneven portion is formed by performing the roughening treatment, the line roughness of the tapered portion 21 is examined for the prototypes 1 to 3 in order to examine how rough the surface is. Ra was measured. For each of the prototypes 1 to 3, five brush hairs 10 planted in the hair-planting holes 3 of the head portion 2 were randomly taken out. For each brush bristles 10, the arithmetic line roughness Ra in the range of 1.0 mm to 1.1 mm and the range of 2.0 mm to 2.1 mm from the tip was measured by a laser microscope. The maximum and minimum values were obtained from the measured values of the arithmetic line roughness Ra in each region, and the mean value and standard deviation (SD) were calculated. The results are shown in Table 2.

表２の試作品１、２の結果より、グラインド深さに関わらず、テーパー部２１の表面の線粗さＲａは概ね同等であった。具体的には、グラインド深さが約２．９ｍｍである試作品１、グラインド深さが約４．６ｍｍである試作品２のいずれにおいても、テーパー部２１の先端から１．０ｍｍ～１．１ｍｍの範囲での線粗さＲａの平均値は０．６μｍ以上０．７μｍ以下であった。また、試作品１、２のいずれにおいても、テーパー部２１の先端から２．０ｍｍ～２．１ｍｍの範囲での線粗さＲａの平均値は０．７μｍ以上０．８μｍ以下であった。これはグラインダーによる粗面化処理を行っていない試作品３では、テーパー部２１の先端から１．０ｍｍ～１．１ｍｍの範囲での線粗さＲａの平均値が０．１８３μｍであり、テーパー部２１の先端から２．０ｍｍ～２．１ｍｍの範囲での線粗さＲａの平均値が０．２４７μｍであったのに比べて、高い値であった。

From the results of prototypes 1 and 2 in Table 2, the line roughness Ra on the surface of the tapered portion 21 was almost the same regardless of the grind depth. Specifically, in both the prototype 1 having a grind depth of about 2.9 mm and the prototype 2 having a grind depth of about 4.6 mm, 1.0 mm to 1.1 mm from the tip of the tapered portion 21. The average value of the line roughness Ra in the range of was 0.6 μm or more and 0.7 μm or less. Further, in both the prototypes 1 and 2, the average value of the line roughness Ra in the range of 2.0 mm to 2.1 mm from the tip of the tapered portion 21 was 0.7 μm or more and 0.8 μm or less. This is because in the prototype 3 which has not been roughened by the grinder, the average value of the line roughness Ra in the range of 1.0 mm to 1.1 mm from the tip of the tapered portion 21 is 0.183 μm, and the tapered portion is The average value of the line roughness Ra in the range of 2.0 mm to 2.1 mm from the tip of 21 was 0.247 μm, which was higher than that.

Although the results are not shown, 5 brush bristles 10 were extracted from each of the 3 prototype toothbrushes 1 that had been roughened and measured. As a result, in each of the prototypes, the average value of the line roughness Ra in the range of 1.0 mm to 1.1 mm from the tip of the tapered portion 21 was approximately 0.4 μm or more and 0.9 μm or less. Further, the average value of the line roughness Ra in the range of 2.0 mm to 2.1 mm from the tip of the tapered portion 21 was approximately 0.5 μm or more and 1.0 μm or less.

<Evaluation of cleanability>
Next, the cleanability of the toothbrush 1 of the example in which the tapered portion 21 of the brush bristles 10 was roughened to form fine uneven portions and the toothbrush 1 of the comparative example not subjected to the roughening treatment. Evaluation was performed.

(Example 1)
A hair bundle made of polybutylene terephthalate and having a circular cross-sectional shape in the radial direction in each of the 41-hole flocked holes 3 formed on the flocked surface 2a of the head portion 2 having the shape shown in FIG. 1 (b). Was folded in half and inserted, and a flat wire was fitted to fix it. The width of the head portion in the lateral direction is 15.2 mm, and the flocked area is 2.10 cm ² . As the brush bristles 10, those having a width (diameter) of 0.178 mm and having a tapered portion 21 formed by chemically treating the tip thereof were used. The chemical treatment of the filament was carried out under the same conditions as those of prototypes 1 to 6. The number of brush bristles 10 filled in each bristles 3 was 18 to 25. The protrusion length H1 of the brush bristles 10 from the flocked surface 2a was set to about 11.0 mm.

After that, a grinder was applied to the tip of the brush bristles 10 to mechanically roughen the surface of the tapered portion 21 to form fine uneven portions. The grind depth was about 2.5 mm from the tip of the hair bundle. The toothbrush 1 thus produced was designated as Example 1.

(Comparative Example 1)
It was created in the same manner as in Example 1 except that the tip of the brush bristles 10 was not subjected to a grinder and the surface of the tapered portion 21 was not mechanically roughened. The toothbrush 1 thus produced was designated as Comparative Example 1.

(Cleanability evaluation test 1)
The cleanability evaluation test 1 was performed on the toothbrush 1 of Example 1 and Comparative Example 1. In the cleanability evaluation test 1, a jaw model coated with artificial plaque was prepared, and the robot was provided with the toothbrush 1 of Example 1 and Comparative Example 1 in a state where the jaw model (upper jaw) # 26 to # 23 was held. The buccal side of the tooth was brushed for 2 seconds per tooth with an average brushing pressure of 200 g, a stroke of 20 mm, and a speed equivalent to 150 rpm. After brushing, the removal rate (%) of artificial plaque on the entire tooth surface and between the teeth was calculated. The results are shown in Table 3 and FIG.

表３及び図３より、テーパー部２１の表面に機械的な粗面化処理を行って微細凹凸部を形成した実施例１の歯ブラシ１では、粗面化処理を行っていない比較例１の歯ブラシ１より、歯面、歯間でともに、清掃性が向上していた。実施例１の歯ブラシ１は比較例１の歯ブラシ１に比べて、歯面での清掃性は３０％以上向上しており、歯間での清掃性は４０％近く向上していた。テーパー部２１の形状が同等でありながら、テーパー部２１の表面に微細凹凸部が形成されていることにより、歯垢の除去性能が顕著に向上することがわかった。

From Table 3 and FIG. 3, the toothbrush 1 of Example 1 in which the surface of the tapered portion 21 is mechanically roughened to form a fine uneven portion is the toothbrush of Comparative Example 1 in which the surface is not roughened. From 1, the cleanability was improved both on the tooth surface and between the teeth. Compared with the toothbrush 1 of Comparative Example 1, the toothbrush 1 of Example 1 was improved in cleanability on the tooth surface by 30% or more, and the cleanability between teeth was improved by nearly 40%. It was found that the shape of the tapered portion 21 was the same, but the fine uneven portion was formed on the surface of the tapered portion 21, so that the plaque removing performance was significantly improved.

(Cleanability evaluation test 2)
The cleanability evaluation test 2 was performed on the brush bristles 10 of the toothbrush 1 of Example 1 and Comparative Example 1. In the cleanability evaluation test 2, it was verified how much plaque was entangled and captured by the roughened tapered portion 21. A colored powder of spray occlude for occlusal check (Pascal, USA) was applied on the wrap, and the toothbrush 1 of Example 1 and Comparative Example 1 was reciprocated on the occlude at intervals of 5 cm. The bristles of the toothbrush 1 after reciprocation were photographed with a microscope (trade name VHX-6000, manufactured by KEYENCE CORPORATION), and color tone analysis was performed with Photoshop (registered trademark). In the color tone analysis, the captured image was binarized with Photoshop (registered trademark), and the occlude adhesion rate (%) was calculated. The results are shown in Table 4 and FIG.

表４の結果より、テーパー部２１の表面に微細凹凸部が形成されて線粗さＲａが大きくなっている実施例１の歯ブラシ１のブラシ毛１０では、微細凹凸部が形成されていない比較例１の歯ブラシ１のブラシ毛１０に対して、オクルード付着率が２倍以上に上昇していた。図４（ａ）の画像では、テーパー部２１において粗面化処理された部分の長さ方向全体に亘ってオクルードが付着していることが観察された。これに対して、図４（ｂ）の画像では、オクルードは、ブラシ毛１０の先端のみに付着しているに過ぎなかった。これにより、テーパー部２１が粗面化処理されていることにより、口腔内に残存した歯垢が効率的に掻き出されるとともに、テーパー部２１の表面に絡め捕られるような状態となることがわかった。

From the results in Table 4, in the brush bristles 10 of the toothbrush 1 of Example 1 in which the fine uneven portion is formed on the surface of the tapered portion 21 and the line roughness Ra is large, the fine uneven portion is not formed in the comparative example. The occlude adhesion rate was more than doubled with respect to the brush bristles 10 of the toothbrush 1. In the image of FIG. 4A, it was observed that occlude adhered to the entire length direction of the roughened portion in the tapered portion 21. On the other hand, in the image of FIG. 4B, the occlude was only attached to the tip of the brush bristles 10. As a result, it was found that the surface of the tapered portion 21 was roughened, so that the plaque remaining in the oral cavity was efficiently scraped off and the taper portion 21 was entangled and caught on the surface of the tapered portion 21. rice field.

H1 ... Overhang length L1, L2, L3, L4, L5 ... Width 1 ... Toothbrush 2 ... Head part 2a ... Flocked surface 3 ... Flocked hole 4 ... Hair bundle 10 ... Brush bristles 21 ... Tapered part

Claims (4)

A toothbrush in which a hair bundle composed of a plurality of brush bristles is fixed to each of a plurality of flocked holes formed on the flocked surface of the head portion.
The brush bristles have a tapered portion whose radial width gradually decreases toward the tip.
The tapered portion has a radial cross-sectional width at a position 1.0 mm from the tip of the brush bristles, which is 25% or more and 55% or less of the radial width of the filament forming the brush bristles. The width of the radial cross section at a position 2.0 mm from the tip is 50% or more and 90% or less of the radial width of the filament forming the brush bristles.
A toothbrush characterized in that a fine uneven portion is formed on the surface of the tapered portion by a mechanical roughening treatment. Claim 1 is characterized in that the surface of the tapered portion has an average value of line roughness Ra of 0.4 μm or more and 0.9 μm or less in the range of 1.0 mm to 1.1 mm from the tip of the brush bristles. Toothbrush described in. Claim 1 is characterized in that the surface of the tapered portion has an average value of line roughness Ra of 0.5 μm or more and 1.0 μm or less in the range of 2.0 mm to 2.1 mm from the tip of the brush bristles. Or the toothbrush according to 2. It is a method for manufacturing a toothbrush in which a hair bundle composed of a plurality of brush bristles is fixed to each of a plurality of flocked holes formed on the flocked surface of the head portion.
A chemical treatment step of chemically treating the filament to form the brush bristles having a tapered portion at the tip thereof whose radial width gradually decreases toward the tip.
A hair transplanting step of fixing a hair bundle formed by bundling a plurality of brush hairs to each of the plurality of hair transplanting holes, and a hair transplanting step.
A method for manufacturing a toothbrush, which comprises a roughening treatment step for mechanically roughening the surface of the fixed hair bundle.

Images