KR101320827B1 - Toothbrush - Google Patents

Abstract

The present invention provides a toothbrush in which mechanical breakage such as bridging and bending of the bridging is difficult to occur, and the replacement timing of the toothbrush is clearly defined by the degree of bridging of the bristles. The toothbrush which implanted the bristle bundle 15 which bundled the bristle bristle which consists of polytrimethylene terephthalate resin on the hair-planting surface WHEREIN: The surface of a bristle has a some recessed part, and the minimum of the bristle in the position in which the recessed part 2 was formed. The cross-sectional area is 40% or more and 80% or less of the maximum cross-sectional area of the bristle.

Description

Toothbrush {TOOTHBRUSH}

This invention relates to the toothbrush using the bristles which consist of polytrimethylene terephthalate (PTT) resin.

This application claims priority with respect to Japanese Patent Application No. 2006-252676 for which it applied on September 19, 2006, and uses the content here.

In general, synthetic resins such as nylon resin (6-12 nylon, 6-10 nylon) and polybutylene terephthalate (PBT) resin are used for the bristles of the toothbrush, and some of the natural hair such as pig hair is also used. It is used.

Moreover, in recent years, the toothbrush using monofilament which consists of polytrimethylene terephthalate (PTT) resin which is polyester resin as a bristle (for example, refer patent document 1, patent document 2, patent document 3), transparency, flexibility The toothbrush which consists of polytrimethylene terephthalate type monofilament which has durability is proposed (for example, refer patent document 4 and patent document 5). Toothbrushes using PTT resin as the bristle are excellent in flexural recovery and flexibility, and thus, the bristle is less likely to open and high brushing power can be maintained for a long time as compared with the case where nylon resin or PBT resin is used.

However, toothbrushes made of PTT resin, which are brittle, are difficult to open up and the toothbrush replacement time is unclear. Therefore, the toothbrush is used for a long time, and the repetitive force is continuously applied to the bristle. This may happen.

In order to provide the toothbrush which does not break the bristle which consists of PTT resin, the toothbrush which uses the synthetic resin monofilament which consists of PTT resin and polyester-type resin as a bristle is proposed (for example, refer patent document 6). .

In addition, in order to indicate the deterioration state in the toothbrush using the bristle which consists of PTT resin, the PTT bristle used for bristle is a double core-in-sheath structure, and the color or color density of a bristle changes with abrasion. Is proposed (see Patent Document 7). In the technique described in Patent Literature 7, it is possible to notify the toothbrush replacement time regardless of the extent of the hairline spreading.

On the other hand, as bristle of a toothbrush, unevenness | corrugation is formed in the circumference | surroundings of brush brim and the whole cut end surface, and cleaning of a tooth and massage of a gum are favorable (refer patent document 8). As a toothbrush using PTT resin, there is also a toothbrush in which braided bristles in which thin threads are woven by braiding processing around a core material made of PTT fibers (see Patent Document 9). ).

Patent Document 1: Japanese Patent Application Laid-Open No. 8-173244

Patent Document 2: International Publication WO 01/75200 Pamphlet

Patent Document 3: Japanese Patent Application Laid-Open No. 2001-511379

Patent Document 4: Japanese Patent Application Laid-Open No. 2006-2256

Patent Document 5: Japanese Patent Application Laid-Open No. 2006-37273

Patent Document 6: Japanese Patent Application Laid-Open No. 2005-270366

Patent Document 7: Japanese Patent Application Laid-Open No. 2005-103184

Patent Document 8: Japanese Patent Application Laid-Open No. 61-177027

Patent Document 9: Japanese Patent Application Laid-Open No. 2004-81647

However, the toothbrush provided with the bristle using the conventional PTT resin may not be used for a long time because neither bristle is easy to open, and the mechanical fracture such as bridging and bending of the bristle could not be sufficiently prevented.

This invention is made | formed in view of the point mentioned above, and an object of this invention is to provide the toothbrush which cleared the toothbrush replacement time by the extent to which a brittleness is hard to occur and the bristles open | release.

(MEANS FOR SOLVING THE PROBLEMS)

MEANS TO SOLVE THE PROBLEM This inventor examined as follows about the mechanical rupture of PTT bristle, and invented the toothbrush of this invention.

That is, when PTT bristle is implanted in a toothbrush, since hair is hard to open by high bending recovery property, it uses for a long time compared with the case where nylon resin or PBT resin is used. Therefore, the load on the bristles by brushing also lasts for a long time. Usually, the bristles of the toothbrush are straight in shape, and the stress applied to the bristles at the time of removal is concentrated on the root of the bristle (the bottom part implanted in the bristle bed), and a large load is placed on the bristle of the bristle. For this reason, mechanical breakage such as cracking and breaking of the appearance occurs at the root of the appearance.

In addition, in order to prevent mechanical breakage of the PTT bristles, it may be considered to clarify the timing of replacement of the toothbrush, prompt replacement of the toothbrush, and replace the toothbrush before mechanical breakage occurs in the PTT bristles. In order to clarify the timing of replacement of the toothbrush, it is possible to thin the bristle diameter to make the bristle easily open and to visually judge. However, if only the diameter of the bristle is made thin, the bristle becomes flexible, the reduction of the reducing force and the strength of the bristle are lowered, which may cause the brittleness of the bristle.

Therefore, the present inventor has intensively studied, so that the stress applied to the appearance of the PTT appearance is not concentrated only on the origin of the appearance, and the degree of appearance of the appearance of the PTT appearance is increased. By forming the shape corresponding to the deteriorated state of the present invention, the toothbrush of the present invention can be clarified while ensuring sufficient durability, and the mechanical breakdown of the PTT feature can be prevented.

The toothbrush of this invention is a toothbrush which implanted the hair | bristle bundle which bundled the bristle which consists of PTT resin on a hair-planting surface, The surface of the said bristle has a some recessed part, The said bristle in the position in which the said recessed part was formed. The minimum cross-sectional area of is characterized in that 40% or more and 80% or less of the maximum cross-sectional area of the bristle.

As described above, when a plurality of recesses are formed on the surface of the bristle, since the stress applied to the bristle at the time of shaping is dispersed in the plurality of recesses, the stress at the time of shaping does not concentrate on the origin of the bristle, and the surface of the bristle In comparison with the case where the recess is not formed, the stress applied to the root of the bristle is reduced.

In addition, when the recess is formed on the surface of the bristle, the bristle tends to open due to the stress on the recess that is loaded at the time of the removal, so that the timing of replacing the toothbrush can be clearly visualized, and mechanical fracture occurs in the bristle. You may be prompted to change your toothbrush before. Therefore, according to this invention, the toothbrush is hard to be cracked and a wrinkle is hardly produced, and a replacement time is clear.

In the toothbrush of the present invention, the concave portion has a pitch of 0.3 mm or more and 1.2 mm or less in the stretch direction of the bristle, and a length of 0.1 mm or more and 0.8 mm or less in the stretch direction, and 0.1 to 0.5 times the depth of the bristle diameter. It can be set as follows.

By setting the pitch, the length and the depth of the concave portion in the above-described ranges, the unfolding ratio of the bristles of the PTT wool can be made more favorable, and high mechanical strength can be ensured.

In addition, the bristle diameter here means a diameter when a bristle cross-sectional shape is circular, and shows the length of 1 side when a bristle cross-sectional shape is regular polygons, such as an equilateral triangle and a square.

(Effects of the Invention)

According to the present invention, it is possible to prevent cracking and bending of the bristle by reducing the stress concentration applied to the root of the bristle. And, visually, the timing of exchange can be clarified.

1 is a side view showing an example of the toothbrush of the present invention.

FIG. 2 is an enlarged perspective view showing an enlarged view of one of the bristles constituting the toothbrush shown in FIG. 1. FIG.

FIG. 3 is a side view of the feature shown in FIG. 2. FIG.

4 is a cross-sectional view of the bristle shown in FIG. 2, in which a concave portion is formed;

(Description of Major Symbols in the Drawing)

1: appearance 2: recess

10 toothbrush 11 head portion

12: seeding cotton 13: handle portion

15: hair bundle 21, 22: recessed unit

A: pitch B: length (width) in the stretching direction

C: Depth D: Hair Diameter (Weight)

E: central axis S1: minimum cross-sectional area

S2: maximum cross-sectional area

EMBODIMENT OF THE INVENTION Next, embodiment of this invention is described in detail using drawing. In addition, this invention is not limited to embodiment described below.

1 is a side view showing an example of a toothbrush of the present invention. 2 is an enlarged perspective view which expands and shows one of the bristle which comprises the toothbrush shown in FIG. FIG. 3 is a side view of the bristle shown in FIG. 2, and FIG. 4 is a cross-sectional view of a portion where the concave portion of the bristle shown in FIG. 2 is formed.

The toothbrush 10 shown in FIG. 1 is provided with the head part 11 which has the seeding surface 12, and the handle part 13 extended from the rear end of the head part 11. As shown in FIG. The handle part 13 is for holding the toothbrush 10 and can be made into any shape suitable for the sawing operation using the toothbrush 10.

The head part 11 and the handle part 13 can be formed by integral molding with resin, such as hard resin, for example. In addition, as resin which comprises the handle part 13, you may use flexible resin, such as an elastomer, at least one part, in order to make it easy to hold.

As a material of the head part 11 and the handle part 13, specifically, a polystyrene resin (PS), a polypropylene resin (PP), a polyethylene terephthalate resin (PET), an acrylonitrile butadiene styrene resin (ABS), Cellulose propionate resin (CP), polyarylate resin, saturated polyester resin (PCTA, PCTG), polycarbonate resin (PC), acrylonitrile styrene resin (AS), polyacetal resin (P0M), polybutylene Materials such as terephthalate (PBT) and biodegradable resins may be used alone or in combination. Moreover, it is also preferable to set it as the multi-color shaping | molding handle combined with these resin, thermoplastic elastomer, silicone resin, etc. In addition, the material of the head part 11 and the handle part 13 is not restrict | limited by the said base material.

The hair | bristle bundle 15 which bundled the bristle | bristle bundle is implanted in the seedling surface 12 of the head part 11. As a hair-planting method of fixing the hair | bristle bundle 15 to the head part 11, it can be fixed by the method of a prior art, For example, hard plastics, such as a flat line (metals, such as brass and stainless steel, and biodegradable plastics, etc.) A pair of flat hairs for folding the hair bundle 15 into two hairs with a fall prevention member), and one end of the hair bundle 15 by means of heat or the like, and the resin that becomes the head portion 11 while the coupling portion is in the mold. In-mold flock (e.g., Japanese Patent Application Laid-Open No. 61-268208, Japanese Patent Application Laid-Open No. 9-512724), and heat fusion to melt-bond one end of the hair bundle 15 and the head portion 11 by means of heat or the like. It can be performed by methods such as planting (for example, Japanese Patent Laid-Open No. 60-241404).

In addition, the shape of the hair-frilling hole formed in the woolen surface 12 may be made into another shape of long diameter and short diameter, such as a regular circle | round | yen or a square hole or a rough oval, a roughly rectangular shape, and a rough rectangle. In addition, although the tuft hole is normally arranged in a grid | lattice shape or zigzag shape, the combination of the tuft hole shape and a combination of arrangement can be suitably selected according to a target function. Further, the head 11 is not limited at all in shape and size design, and, for example, as the minimum thickness of the head 11, in accordance with a method of weaving using flat lines or a method of weaving without flat lines. A slight difference is seen, but it can be as thick as 2 mm to 6 mm.

The bristle 1 which comprises the hair | bristle bundle 15 of the toothbrush 10 shown in FIG. 1 consists of polytrimethylene terephthalate (PTT) resin. In addition, the monofilament used as bristle 1 can be modified in the range which does not significantly impair the characteristic of bristle 1. Specifically, for example, a PTT resin that becomes a monofilament may be a modifier such as a stabilizer against heat or light, a flame retardant, a filler, a surface lubricant, an antistatic agent, a sterilizing material (antibacterial material), or other hard resins. A steamer etc. may be suitably mix | blended 1 type, or 2 or more types, or may be apply | coated to monofilament.

In addition, the bristle 1 can be used as a transparent (natural) bristle, can also be used as a transparent coloring bristle with a pigment or a dye, or opaque coloring (including white) bristle, and the external appearance of the toothbrush 10 It is appropriately selected in consideration of its commerciality. The transparent bristle, transparent coloring bristle, and opaque coloring (including white) bristle may be used in combination of two or more of them in a bristle unit or bristle, as necessary.

Colored hairs, such as transparent colored hairs and opaque colored hairs (including white) hairs, are commonly used for coloring the resin itself during spinning, or after the spinning or spinning process, and coloring on the surface. It can manufacture by a method etc. to. In addition, in the cut-piece state (bundle of the bristle length of about 25-35 mm) before hair-planting to the toothbrush 10, or after hair-planting, only the tip part of the bristle 1 or all of bristle 1 can be colored. Can be.

When the concave portion 2 is provided on the surface of the bristle 1, since the stress applied to the bristle at the time of shaping concentrates on the concave portion 2, the stress applied to the root of the bristle 1 is reduced, and the bristle ( 1) is easy to open. However, in order to sufficiently prevent cracking and bending of the bristle 1, it is not necessary only to provide the recessed part 2 in the surface of the bristle 1, but the bristle 1 in the position in which the recessed part 2 was formed, 1 It is necessary that the minimum cross-sectional area S1 of) is 40% or more and 80% or less of the largest cross-sectional area S2 of the bristle 1.

As shown in FIG. 4, the minimum cross-sectional area S1 here is the bristle cross-sectional area which becomes the minimum when cut | disconnected perpendicularly to the long side direction of a bristle part in a recessed part (interval part in drawing). In addition, largest cross-sectional area S2 is the bristle cross-sectional area obtained by extrapolating the line obtained following the outermost side before and behind the recessed part formed in bristle.

If the minimum cross-sectional area S1 is less than 40% ((S1 / S2) x 100 <40 (%)) of the maximum cross-sectional area S2 of the bristle 1, the mechanical strength of the portion where the recess 2 is formed is significantly lowered. As a result, the original strength as the bristle 1 cannot be exhibited, and the bending strength is remarkably lowered. Further, the bridging of bristle 1 by brushing is about the same as that of general nylon bristle, and the advantages of bending durability possessed by PTT bristle are lost. On the other hand, when the minimum cross-sectional area S1 exceeds 80% of the maximum cross-sectional area S2 of the bristle 1 ((S1 / S2) × 100> 80 (%)), because of the excellent bending durability of the PTT resin, Opening of the bristle 1 becomes inadequate, the timing of replacement becomes indefinite, and the bristle of bristle 1 by continuous use may occur.

Moreover, it is preferable that pitch A of the recessed part 2 shown in FIG. 3 is 0.3 mm or more and 1.2 mm or less, More preferably, it is 0.5 mm or more and 1.0 mm or less. In addition, the pitch A of the recessed part 2 here means the distance between the recessed parts 2 adjacent to the elongation direction of the bristle 1. In addition, the distance between the adjacent recessed parts 2 means the distance between the extension direction center positions of the bristle 1 in the recessed part 2. Moreover, it is preferable that the length B (width) of the recessed part 2 in the extension direction is 0.1 mm or more and 0.8 mm or less, More preferably, it is 0.2 mm or more and 0.5 mm or less.

In addition, the depth C which is the distance from the line which follows the outermost side of the recessed part 2 shown in FIG. 3 and FIG. 4 to the bottom of the valley of the recessed part 2 is 0.1 times or more of the bristle diameter D. FIG. It is preferable that it is 0.5 times or less, More preferably, it is 0.1 times or more and 0.3 times or less.

In addition, the thickness of the bristle 1 is preferably 3 to 10 mils (0.076 to 0.254 mm), preferably 5 to 8 mils (0.125 to 0.203 mm), in consideration of usability, chain feeling, cleaning effect, durability, and the like. You may use combining the plurality of bristles of which thickness differs as the bristle which comprised one toothbrush. Particularly, in the specification in which a plurality of hair-frilling holes are arranged on the woolen surface 12, hardening or changing the strength of the hair from the outside toward the center (thickness, material, length, color, cross-sectional shape) is a feeling of use and appearance. It is also preferable to form a differential.

In addition, the cross-sectional shape of the bristle may be an indefinite form in which a straight line such as a circle, an ellipse, a triangle, a quadrangle, a star, a straight line such as a 3-leaf or a 4-leaf clover, a curve, or a combination of a straight line and a curve.

Although the manufacturing method of the monofilament used as such bristle 1 is not specifically limited, For example, it can manufacture using the method of manufacturing a normal coextrusion monofilament, etc.

Moreover, the formation method of the recessed part 2 provided in the surface of the bristle 1 is not specifically limited, either, For example, before or after an extending process, annealing process, etc. when manufacturing a monofilament, For example, a roller having a U-shaped convex portion can be disposed to face up and down or to the left and right in view of the cross section corresponding to the shape of the recessed portion 2, and can be formed by passing a monofilament between the rollers disposed to face each other. In addition, when passing the monofilament between the rollers which oppose, the recessed part 2 can also be formed by letting a monofilament pass between the rollers which oppose while performing heat processing.

In addition, the formation position of the recessed part 2 is not limited to the said embodiment. For example, in the said embodiment, although the row of recessed part units 21 and 22 are provided in the surface of the bristle 1, the recessed part unit may be one row. In addition, in the said embodiment, although the 2 rows of recessed part units 21 and 22 are arrange | positioned symmetrically with respect to the central axis E of the bristle 1, the recessed part unit in the extending direction of the bristle 1 ( The position of the recessed portion 21 may be disposed so as to be the center of the adjacent recessed portion of the recessed unit 22.

The shape of the concave portion 2 of the bristle 1 may be a c-shape, a V-shape, a U-shape, or a C-shape in view of the cross section in the stretching direction of the bristle 1. In addition, the shape of all the recessed parts which the bristle 1 has may be the same, and one part or all may differ. The concave portion of the bristle may be a groove provided over the entire circumference of the bristle. Moreover, although it is preferable to implement especially the recessed part of a bristle over the full length of a bristle, what is necessary is just to select suitably according to the magnitude | size of a recessed part, the cross-sectional shape of a bristle, a bristle diameter, etc.

When forming a concave portion having such a shape, a roller having a convex portion corresponding to the shape of a concave portion to be formed, such as a hemispherical shape, a rough polygon (rectangle, triangle), a rough oval, etc. By using it, it can form similarly to the bristle 1 of the said embodiment.

Moreover, as another example of the bristle 1 provided with the recessed part 2 in the surface, for example, when spinning the bristle 1, the inorganic substance was previously put into the master batch, and the surface precipitation of the bristle | bristle spinning using this was carried out. And a feature in which random recesses are provided on the surface obtained by dissolving powder.

In addition, the mother wire may be tapered by a chemical method of dissolving the bristle in an acid or an alkali chemical agent, or by a polishing method in which the mother wire is mechanically polished after planting in a toothbrush. As a grinding | polishing method, for example, the taper which smoothed between the vestibular face and the planting surface of the hair-shape by the grinding | polishing body which the bearing body which supports a 1st rotating shaft rotates along a 2nd rotating shaft, rotating along a 1st rotating shaft, for example. The method using the apparatus which processes and manufactures to a shape is mentioned.

In addition, the depth of the recessed part in the case of making a mother wire into a taper shape means the distance from the line obtained continuously to the outermost side before and behind the recessed part formed in a tapered part, and the valley bottom of a recessed part.

In addition, according to the difference of the manufacturing method of the toothbrush 10, after the spinning, the bristle | bristle bundle may be tied up by predetermined number and wound up in a spool, or it cuts to a fixed length, and bundles it with the diameter of several centimeters from about 10 cm on a straight line, After the film is wound with a film, in order to further reduce the residual strain of the bristle layer, for example, offline heat treatment may be performed for several days from 60 ° C to 160 ° C for several minutes.

In addition, the hair | bristle shape (or profile) shape and bristle length of the edge part of the toothbrush 10 can be arbitrarily set, For example, it becomes a single planar shape, a mountain shape, or an uneven | corrugated shape. The shape may be different from the outside, the inside, the front end, the rear end, or the like.

Although an Example is shown to the following and this invention is demonstrated to it in more detail, this invention is not limited to these Examples.

"Examples 1 to 10 and Comparative Examples 1 to 3"

The hair | bristle bundle which bundled the bristle which consists of PTT resin shown in Table 1 or Table 2 was planted on the woolen surface which has 23 tuft holes, and the head part and the handle part manufactured the toothbrush which consists of PCTA resin.

`` Comparative Example 4 ''

A toothbrush was manufactured in the same manner as in Examples 1 to 10 and Comparative Examples 1 to 3, except that a bristle made of nylon resin was used.

Table 1 or Table 2 shows a side view of the bristle used for the toothbrushes of Examples 1 to 10 and Comparative Examples 1 to 4, a cross-sectional view at the position of the arrow shown in the side view, and a maximum with respect to the minimum cross-sectional area S1. The ratio of the cross-sectional area S2 ((S1 / S2) x 100 (%)), the dimension of the appearance (pitch, depth, width), and the appearance diameter are shown. In addition, in the sectional drawing of Table 1 and Table 2, the area of the part shown with the diagonal line is the minimum cross-sectional area S1, and the part enclosed with the dotted line is the maximum cross-sectional area S2.

[Table 1]

[Table 2]

Using the toothbrush of Examples 1-10 and Comparative Examples 1-4, the (1) bristle durability test and (2) sensory evaluation shown below were performed. The results are shown in Table 3.

[Table 3]

(1) appearance durability test

The toothbrushes of Examples 1 to 10 and Comparative Examples 1 to 4 were set in a model durability tester, and as shown below, the test of the hair opening and the brittleness of the hair was performed. In the test method, the head part of the toothbrush is placed on a metal wave plate and is placed in parallel with the wave plate with the bristle tip in contact with the surface of the wave plate, and the head part of the toothbrush and the whole of the wave plate are placed in hot water at 35 ° C. Immerse. Then, in a state in which 400 g of load is applied to the head portion of the toothbrush, the head portion is squeezed by reciprocating 100,000 times at a reciprocating speed of 150 times / minute and a stroke stroke of 40 mm in the direction of passing the wave of the wave plate. The rate of bulging and brittleness were evaluated.

<Plant spread rate>

Before the dehydration (before the bristle endurance test), the width of the bristle part of the bristles group implanted into the head part (full width at the hairline position of the bristle group in the direction perpendicular to the handle long side direction) was measured, and the model was measured. After decrementing a predetermined number of times (100,000 times) in the durability tester, the hair width of the hair is again measured, and the difference is divided by the width of the hair before the hair removal and displayed as a percentage of 100 times. In addition, the hair | bristle part width | variety was measured in the position containing the hair | bristle bundle toward the outermost. In addition, the hair opening spread rate was evaluated based on the following criteria.

Hair growth rate (%) = ((hair width after hair removal-hair width before hair loss) / (hair width before hair loss)) × 100

○: 30% or more but less than 60%

△: 20% or more but less than 30% or 60% or more but less than 80%

×: less than 20% or 80% or more

<Feather bent>

After the predetermined number of times of depletion, the presence or absence of the occurrence of the break of the bristle root was visually observed and evaluated according to the following criteria.

○: no appearance bending

×: appearance bending occurs

(2) sensory evaluation

The toothbrushing state of the toothbrush and whether or not the replacement time was linked were evaluated by the following criteria for seven-step sensory evaluation by 20 professional panelists using the toothbrush after the brush durability test was completed.

1: do not link at all

2: don't link pretty

3: don't link very much

4: I can't say either

5: link slightly

6: Pretty Linking

7: very linked

○: 6 or more average points

(Triangle | delta): An average score is more than 4 points and less than 6 points

×: 4 points or less

Comprehensive evaluation was judged based on the results of the unfolding rate of the mother-in-law, brittleness, and sensory evaluation.

○: Everyone is `` ○ ''

(Triangle | delta): Evaluation is "(circle)" or "(triangle | delta)" and there is no "x".

X: There is "x" in either

As shown in Table 1 thru | or Table 3, Example 1 thru | or implementation which a plurality of recessed parts are formed in the surface of the bristles, and the minimum cross-sectional area S1 of a bristle is 40% or more and 80% or less of the maximum cross-sectional area S2 of a bristle. In Example 10, all of evaluation of the brittleness became (circle), and comprehensive evaluation became (circle) or (triangle | delta).

On the other hand, in the comparative example 1 in which the recessed part is not formed in the bristle, and the comparative example 2 in which the depth of a recessed part is shallower than the preferable range, and the ratio of the largest cross-sectional area S2 with respect to minimum cross-sectional area S1 exceeds 80%, The hair spreading rate was very low, and the evaluation of the hair spreading rate became x. Moreover, in Comparative Example 1 and Comparative Example 2, the sensory evaluation degree was also x, and it turned out that the extent to which a bristles open | releases (germ part spreading rate) does not correspond to the toothbrush replacement time. In addition, in Comparative Example 1 and Comparative Example 2, the evaluation of the bridging of the bristles was also x, and the overall evaluation was also x.

In addition, in Comparative Example 3 in which the ratio of the maximum cross-sectional area S2 to the minimum cross-sectional area S1 was less than 40%, and Comparative Example 4 using the bristle made of nylon resin, the bridging part unfolding ratio was very high. The evaluation of the unfolding rate of the hair-fed part became x.

Next, another example of the present invention is shown.

"Examples 11 to 18"

The toothbrush was manufactured like Example 1 thru | or 10 and Comparative Example 1 thru | or Comparative Example 4 except having used the bristle which consists of PTT resin shown in Table 3.

Table 4 shows a side view of the bristle used for the toothbrush of Examples 11 to 18, a cross-sectional view at the position of the arrow shown in the side view, and a ratio of the maximum cross-sectional area S2 to the minimum cross-sectional area S1 ((S1 / S2). ) X 100 (%)), the feature size (pitch, depth, width), and feature size. In addition, in sectional drawing of Table 4, the area of the part shown with the oblique line is the minimum cross-sectional area S1, and the part enclosed with the dotted line is the maximum cross-sectional area S2.

[Table 4]

Using the toothbrush of Examples 11-18, it carried out similarly to Examples 1-10, and Comparative Examples 1-4, (1) bristle durability test, and (2) sensory evaluation. The results are shown in Table 5.

[Table 5]

As shown in Table 4 and Table 5, the several recessed part is formed in the surface of the bristles, and the minimum cross-sectional area S1 of a bristle is 40% or more and 80% or less of the maximum cross-sectional area S2 of a bristle, Example 11-Example In Example 18, all evaluation of the brittleness became (circle), and comprehensive evaluation became (circle) or (triangle | delta).

The toothbrush of this invention can prevent the bridging and bending of a bristle by reducing the stress concentration applied to the root of bristle. Moreover, according to this invention, it becomes possible to provide the toothbrush which can visually clarify an exchange time.

Claims (2)

In the toothbrush which planted the hair | bristle bundle which bundled the bristle which consists of polytrimethylene terephthalate resin on the hair-planting surface, A plurality of recesses are formed in the surface of the said bristle, The minimum cross-sectional area of the said bristle in the position in which the said recess was formed is 40%-80% of the maximum cross-sectional area of the said bristle, The toothbrush characterized by the above-mentioned. The method of claim 1, The said recessed part is a toothbrush of the pitch of the said bristle direction being 0.3 mm or more and 1.2 mm or less, the length of the said stretching direction being 0.1 mm or more and 0.8 mm or less, and the depth being 0.1 times or more and 0.5 times or less of the bristle diameter.

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