JP6849190B2 - Bristles for brushes and brushes using them - Google Patents

Description

The present invention relates to a brush bristle material suitable for various brushes including a toothbrush and a brush using the same.

Conventionally, a technique of using a synthetic fiber monofilament as a hair material for a brush is widely known. A brush using such a bristles for a brush, for example, a toothbrush, is desired to have an excellent cleaning effect by the bristles, and further, an excellent scraping performance of dirt and plaque during cleaning by the bristles. Is desired to have.

However, it may be difficult to meet such a requirement if the brush bristles are formed of a single material monofilament up to the bristles. That is, in the case of a monofilament made of a single material up to the tip of the hair, the cleaning effect of the tip of the hair itself may be limited, and it is difficult to obtain excellent scraping performance of dirt and plaque by the tip of the hair. There is a risk.

Cleaning and cleaning brushes in other fields have roughly the same problems.

Therefore, in order to particularly improve the cleaning effect, in Patent Document 1, a bristle material made of a composite fiber having a core-sheath cross-sectional structure is formed into a multi-leaf cross-sectional shape having a plurality of concave portions and convex portions on the outer periphery. A toothbrush hair material in which split ends formed of these convex portions are formed in a crown shape at the tip of the hair material and a depression is formed in the central portion of the crown-shaped portion is disclosed. Further, Patent Document 2 discloses a structure of a bristle material for a brush in which a tip portion of a bristle material is formed in a tapered portion and a plurality of grooves extending in the fiber axis direction are formed on an outer peripheral surface of the tapered portion. There is.

However, in the toothbrush hair material disclosed in Patent Document 1, the effect of scraping dirt is exhibited in the crown-shaped portion, and the cleaning effect can be improved by that amount, but the crown-shaped portion is formed. Since a dent is formed between the convex parts, even if dirt is once taken into the dent in the center of the crown-shaped part, the structure is such that the dirt can easily escape through the dent, and the escaped dirt is re-used. The problem remains that it can adhere. Further, since the convex portion forming the crown-shaped portion is formed as an intermittent convex portion protruding from the tip of the hair material, the waist of each convex portion is not so high, and it is resistant to highly viscous stains and the like. There is also the problem that the scraping effect may be reduced. Further, in the brush hair material disclosed in Patent Document 2, since a plurality of grooves extending in the fiber axis direction are formed on the outer peripheral surface of the tapered portion, the dirt scraping performance (cleanability) is improved. Although the effect is recognized, the performance of capturing the dirt once scraped off cannot be expected so much, and further improvement is desired.

Japanese Unexamined Patent Publication No. 2012-105743 Japanese Unexamined Patent Publication No. 2009-089920

Therefore, the subject of the present invention is to pay attention to the remaining problems of the brush bristles as described in the conventional Patent Document 1, and to further improve the dirt scraping performance at the bristles of the bristles. At the same time, it is an object of the present invention to provide a brush bristle material having excellent cleanability, which can satisfactorily capture dirt once scraped without letting it escape, and a brush using the same.

In order to solve the above problems, the brush bristle material according to the present invention is a composite fiber having a core-sheath cross-sectional structure composed of a plurality of resin layers formed of two or more kinds of resins having different chemical dissolution rates in the longitudinal direction. At one end or both ends, at least one annular wall extending in the longitudinal direction of the composite fiber and extending all around along the outer peripheral surface of the composite fiber, and the annular wall inside the annular wall adjacent to the annular wall. It is characterized in that at least one groove extending along the wall and recessed in the longitudinal direction of the composite fiber is formed from the tip of the annular wall.

In such a hair material for brushes according to the present invention, one end or both ends in the longitudinal direction of a composite fiber having a core-sheath cross-sectional structure composed of a plurality of resin layers formed of two or more kinds of resins having different chemical dissolution rates. In the portion, the chemical dissolution treatment is used to appropriately leave the resin layer portion having a slow chemical dissolution rate to form an annular wall, and the resin layer portion having a high chemical dissolution rate is appropriately dissolved to form a groove inside the annular wall. Is formed. That is, in the hair material for brushes according to the present invention, at least one annular wall extending over the entire circumference along the outer peripheral surface of the composite fiber is formed at the tip of the composite fiber constituting the hair material. The annular wall has a so-called edge effect when scraping dirt, and in particular, the annular wall structure that extends continuously over the entire circumference gives the annular wall itself a high waist, so that a high edge effect can be exhibited and the viscosity is high. Excellent scraping performance can be exhibited even for dirt. The dirt scraped off by the annular wall is taken into the groove formed inside the groove and trapped in the groove. Since the groove has a structure surrounded by an annular wall extending from the outside to the entire circumference, dirt trapped in the groove is not easily released beyond the annular wall portion and is well inside the groove. It remains captured. Therefore, the bristles provided with these annular walls and the grooves inside them exhibit excellent cleanability.

In the hair material for brushes according to the present invention, the number of the plurality of resin layers formed of the two or more kinds of resins having different chemical dissolution rates may be two or more, but preferably 3 to 6 layers. Is in the range of. The number of each of the annular wall and the groove inside the annular wall may be at least one. Therefore, when the number of the plurality of resin layers is two, the outermost layer in the radial direction in the cross section of the composite fiber becomes the layer forming the annular wall, and the entire inner portion thereof becomes the layer forming the groove.

The depth of the groove formed inside the annular wall is not particularly limited, but is preferably 0.1 mm or more, more preferably 0.5 mm or more, and further preferably 1 mm or more. The depth of the groove may be set according to the application of the hair material for the brush, and by setting the depth to a specific depth or more, high catching performance can be exhibited even for highly viscous dirt.

The thickness of one resin layer in the cross section of the composite fiber is preferably in the range of 10 to 300 μm, more preferably in the range of 15 to 150 μm. Since each resin layer serves as a portion forming the annular wall and the groove inside the annular wall at the end of the composite fiber, in order to ensure excellent dirt scraping performance by the annular wall and excellent dirt trapping performance by the groove. It is preferable to set the thickness of the resin layer in the above range.

Further, in the hair material for brushes according to the present invention, the diameter of the composite fiber is preferably in the range of 50 to 1,000 μm, more preferably in the range of 80 to 500 μm. If the diameter of the composite fiber is less than 50 μm, the waist of the composite fiber portion itself when used for a brush becomes too weak, and the cleaning effect may be reduced depending on the application. If the diameter of the composite fiber exceeds 1,000 μm, the composite fiber portion itself becomes too stiff when used for a brush, and the root portion of the tip portion depends on the shape of the annular wall and the groove at the tip portion. The composite fiber portion in the above may be strongly pressed against the object to be cleaned, and the object to be cleaned may be easily damaged.

Further, in the hair material for brushes according to the present invention, the length of the composite fiber in the longitudinal direction of the portion having the annular wall and the groove is preferably in the range of 0.5 to 10 mm. Since this length affects the performance of the annular wall having the dirt scraping performance and the groove having the dirt trapping performance as described above, it may be appropriately set from the above range according to the application.

Further, the brush bristle material according to the present invention has an facing wall facing the annular wall with the groove in between, and the longitudinal height of the composite fiber of the facing wall is larger than the height of the annular wall. It is also possible to adopt a high structure. That is, it is a bamboo shoot-like or telescope-like structure in which a higher facing wall exists on the inner diameter side of the fiber with the groove in between of the annular wall. If such a structure is adopted, a tapered tapered shape can be formed as the entire tip of the hair material, so that the hair can be scraped off by the annular wall and the dirt can be captured by the groove as described above. The soft touch of the tip can also be realized.

Further, in the hair material for a brush according to the present invention, various shapes can be adopted as the extending shape of the at least one annular wall, a structure composed of an annular wall extending in a circular shape, and an annular shape extending in a deformed shape other than the circular shape. Any structure consisting of walls can be adopted. The annular wall extending in a circular shape includes not only an annular wall extending in a perfectly circular shape with substantially the same wall thickness, an annular wall extending in a wavy shape, and an annular wall whose wall thickness changes in the extending direction. Walls are also included. Further, the annular wall extending into a deformed shape other than a circle includes an annular wall extending in the form of a triangle, a quadrangle, or a polygon more than that, and any annular wall extending into a deformed shape other than a square shape.

Further, in the hair material for a brush according to the present invention, the cross-sectional shape of the entire composite fiber may be either a circular shape or a non-circular deformed cross-sectional shape. It may be appropriately determined according to the intended use, usage pattern, usage conditions, and the like.

Further, in the hair material for brushes according to the present invention, it is preferable that the plurality of resin layers constituting the composite fiber are provided concentrically. If it is concentric, it can take either a concentric form or a form in which only one of the layers is formed in a polygonal shape other than a circular shape or a deformed cross-sectional shape. By providing the plurality of resin layers concentrically, the desired annular wall and groove in the present invention can be easily formed by the drug dissolution treatment.

The present invention also provides a brush in which the above-mentioned brush bristle material according to the present invention is used at least in a part. In particular, the brush according to the present invention has excellent dirt scraping performance due to the annular wall formed at the tip of the bristle material and excellent dirt trapping performance due to the groove as described above. It is suitable as a makeup brush, an application brush, and the like.

In such a brush according to the present invention, a range of 1 to 50 mm is exemplified as a preferable range of the brush bristles length (length from the brush root to the bristles), although it depends on the use thereof, and more preferably. , 5 to 35 mm.

As described above, according to the present invention, the annular wall formed at the tip of the hair material and the groove formed inside the annular wall have high cleaning performance having both excellent dirt scraping performance and excellent dirt trapping performance. It is possible to provide a hair material for a brush that expresses sex.

Further, according to the present invention, it is possible to provide various brushes using at least a part of the above-mentioned brush bristle material, and particularly to provide a brush suitable as a toothbrush, a tongue brush, a makeup brush, an application brush and the like. Can be done.

A hair material for a brush according to an embodiment of the present invention is shown, FIG. 1 (A) is a schematic vertical sectional view of one end of the hair material, and FIG. 1 (B) is a line BB of FIG. 1 (A). It is a schematic cross-sectional view along. It is a schematic block diagram which shows the flocking method at the time of using a brush hair material for a toothbrush. It is a schematic vertical sectional view of one end part of the hair material for a brush which concerns on another embodiment of this invention. It is a schematic cross-sectional view which shows various form examples of the hair material for a brush which concerns on this invention. It is a schematic cross-sectional view which shows still another various form example of the hair material for a brush which concerns on this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a hair material 1 for a brush according to an embodiment (Embodiment 1) of the present invention, and FIG. 1 (A) shows one end of the hair material 1. As shown in FIG. 1B, the brush bristle material 1 has a plurality of resin layers 2a, 2b, 2c, which are formed of two or more types of resins having different chemical dissolution rates (two types of resins in the illustrated example). 2d, particularly in the present embodiment, is formed of a composite fiber 3 having a core-sheath cross-sectional structure composed of a plurality of resin layers 2a, 2b, 2c, and 2d arranged concentrically with the same thickness in the extending direction. At one end or both ends of the composite fiber 3 in the longitudinal direction (FIG. 1 (A) shows only one end of the hair material 1), the composite fiber 3 extends in the longitudinal direction and the outer peripheral surface of the composite fiber 3. At least one annular wall 4 extending in the direction along the entire circumference, and the composite fiber 3 extending from the tip of the annular wall 4 adjacent to the annular wall 4 inside the annular wall 4 and extending along the annular wall 4. At least one groove 5 recessed in the longitudinal direction is formed. In the present embodiment, the annular wall 4 is formed as a circular annular wall extending with the same thickness in the extending direction thereof, and the groove 5 is an annular wall extending along the annular wall 4 with the same width inside the annular wall 4. It is formed in a groove. The annular wall 4 is formed of a resin layer 2c that is not dissolved in the drug dissolution treatment and is appropriately left, and the groove 5 inside the annular wall 4 is formed by appropriately dissolving the resin layer 2b in the drug dissolution treatment. It is formed as a formed annular space. Further, in the present embodiment, at one end of the hair material 1, the resin layer 2a forms a columnar wall 6 that is not dissolved in the drug dissolution treatment and is appropriately left, and the resin layer 2d dissolves the drug. An annular space 7 is formed by being appropriately dissolved in the treatment.

As the drug dissolution treatment, for example, an alkali treatment can be applied, and examples of the plurality of resin layers formed of two or more types of resins having different chemical dissolution rates (for example, the dissolution rate by the alkali treatment) include the resin layer 2a. 2c is formed of nylon (Ny) (registered trademark) as a resin that cannot be dissolved in alkali, and resin layers 2b and 2d are formed of polybutylene terephthalate (PBT) as a polyester resin that is soluble in alkali. By treating the end portion of the composite fiber 3 in the longitudinal direction with an alkali treatment for a predetermined length and dissolving only the resin layers 2b and 2d at the end portion, the annular wall 4, the groove 5, and the circle as shown in FIG. 1 (A) are dissolved. An end portion of the brush bristle material 1 having the columnar wall 6 and the annular space 7 is formed.

In the brush bristle material 1, the drug is used at one end or both ends in the longitudinal direction of the composite fiber 3 having a core-sheath cross-sectional structure composed of a plurality of resin layers formed of two or more kinds of resins having different drug dissolution rates. By utilizing the dissolution treatment, an annular wall 4 is formed by leaving a resin layer 2c portion having a slow drug dissolution rate (formed from a resin layer that is not dissolved by alkali in the above embodiment), and the drug is dissolved inside the resin layer 4. The high-speed resin layer 2b portion is appropriately melted to form the groove 5. Since the annular wall 4 is formed as an annular wall that extends continuously over the entire circumference in an annular shape, the annular wall 4 can exert a high edge effect when scraping dirt and is excellent against highly viscous dirt. Can exhibit scraping performance. The dirt scraped off by the annular wall 4 is taken into the groove 5 formed inside the groove 5 and captured by the groove 5, but the groove 5 is surrounded by the annular wall 4 extending from the outside to the entire circumference. Due to the structure, the dirt trapped in the groove 5 does not easily escape and is well maintained in a state of being trapped in the groove 5. Therefore, the hair tip portion provided with the annular wall 4 and the groove 5 inside the annular wall 4 exhibits excellent cleanability.

The brush bristle material 1 configured as described above is used at least in part for producing various brushes. Generally, two types of methods are generally known as methods for flocking a brush bristle material to a brush component, and these two methods are taken as an example in the case of use for a toothbrush. This will be described with reference to 2.

FIG. 2A shows a toothbrush 13 in which the brush bristle material 11 is flocked on the head portion of the toothbrush component 12, and as a method of flocking the brush bristle material 11, a- There are two types of methods as shown in FIGS. 2 (B) and 2 (C), which are enlarged cross-sectional views along the line a. In the method shown in FIG. 2B, the brush bristle material 11 folded in half is inserted into the bristle hole 14, and the brush bristle material 11 is fixed to the toothbrush component 12 with a fixture called a flat wire 15. .. The finished toothbrush is commonly referred to as a flat line toothbrush. In such a flat-line toothbrush, both ends of the brush bristles 11 prepared in advance serve as the bristles of the brush. In the method shown in FIG. 2C, one end of the brush bristle material 11 is inserted into the through hole 16 of the head portion surface side member 12a of the toothbrush component member 12, and the end portion of the inserted brush bristle material 11 is inserted. A heating device (not shown) is applied to form a lump for preventing or fixing, which is called a hot-bulb 17, and then the back member 12b of the head is joined to hide the hot-bulb 17 and complete the toothbrush product. Let me. The finished toothbrush is commonly referred to as a flat line toothbrush. In such a non-flat line toothbrush, one end of a brush bristles 11 prepared in advance serves as a bristles of the brush. Therefore, when the brush bristle material 1 according to the present invention is used for a flat toothbrush, the above-mentioned annular wall 4 and the groove 5 inside the annular wall 4 are formed at both ends of the brush bristle material 1. When used for a flat wire toothbrush, the annular wall 4 and the groove 5 are formed at one end of the brush bristle material 1.

FIG. 3 shows one end of the brush bristles 21 according to another embodiment of the present invention (Embodiment 2). In the present embodiment, the brush bristle material 21 is a plurality of resin layers 22a and 22b arranged concentrically and formed of two or more kinds of resins having different chemical dissolution rates (two kinds of resins in the illustrated example). , 22c, 22d, and is formed of a composite fiber 23 having a core-sheath cross-sectional structure. At one end or both ends of the composite fiber 23 in the longitudinal direction (FIG. 3 shows only one end of the hair material 21), the composite fiber 23 extends in the longitudinal direction and is oriented along the outer peripheral surface of the composite fiber 23. At least one annular wall 24 extending over the entire circumference and extending along the annular wall 24 adjacent to the annular wall 24 inside the annular wall 24 in the longitudinal direction of the composite fiber 23 from the tip of the annular wall 24. At least one concave annular groove 25 is formed. In the present embodiment, the resin layers 22a and 22c are composed of, for example, a resin having a slower dissolution rate with respect to alkali as a dissolving agent (for example, polybutylene terephthalate (PBT)), and the resin layers 22b and 22d are composed of, for example, polybutylene terephthalate (PBT). For example, it is composed of a resin having a higher dissolution rate than alkali as a dissolving agent (for example, polyethylene terephthalate (PET)), and is cyclically formed by a resin layer 22c that is appropriately left undissolved in the agent dissolving treatment. The wall 24 has a groove 25 as a facing wall higher than the annular wall 24 by the resin layer 22a which is not dissolved in the drug dissolution treatment and is appropriately left by the resin layer 22b being appropriately dissolved in the drug dissolution treatment. An annular space 27 is formed in the columnar wall 26 in the central portion by appropriately dissolving the resin layer 22d in the drug dissolution treatment. The columnar wall 26 at the center and the annular wall 24 having a lower height form a bamboo shoot-like or telescope-like structure, and the entire tip portion of the hair member 21 is formed in a tapered tapered shape. ..

Even in the brush bristle material 21 having such a tapered tip portion formed into a tapered shape, the annular wall 24 has excellent dirt scraping performance and the groove 25 has excellent dirt trapping performance, as in the first embodiment. Excellent cleaning performance is exhibited, and as compared with the above-mentioned first embodiment, the tip portion is formed in a tapered shape, so that excellent cleaning can be performed even on finer parts (for example, between teeth). It is possible to exert the effect.

Table 1 summarizes the typical features of the first embodiment and the second embodiment when applied to a toothbrush. In the first embodiment, the annular wall is formed of a resin layer made of nylon (Ny) (registered trademark), the groove is formed of a resin layer of polybutylene terephthalate (PBT), and in the second embodiment, the annular wall is formed of polybutylene terephthalate. It was formed of a resin layer made of (PBT), and grooves were formed of a resin layer of polyethylene terephthalate (PET), each of which was formed by an alkali treatment. The characteristics of the bristles for brushes in Table 1 are shown as contrasting characteristics with the bristles for brushes formed of a monofilament of nylon (registered trademark), which is usually a single material, and the tips of the bristles for brushes. The effect of scraping dirt and the effect of catching dirt by the part are shown as comparison characteristics with the hair material described in Patent Document 1 described above. In Table 1, ◯ indicates that the characteristics are equal to or higher than those of the contrast target, and ⊚ indicates that they are significantly superior to the contrast target.

The hair material for a brush according to the present invention may take various forms other than the above-described first and second embodiments. 4 and 5 show various forms in the cross section of the composite fiber.

In the brush bristle material 31 shown in FIG. 4A, the hair material 31 is formed of a composite fiber 33 composed of a resin layer 32a in the central portion, a resin layer 32b on the outer side thereof, and a resin layer 32c on the outermost layer, which are arranged concentrically. At the same time, the resin layer 32b is formed on the annular wall 34, and the resin layer 32a at the center is formed on the inner groove 35 of the annular wall 34. The brush bristle material 41 shown in FIG. 4B is composed of a central resin layer 42a, an outer resin layer 42b, an outer resin layer 42c, and an outermost resin layer 42d arranged concentrically. In addition to being formed on the composite fiber 43, the resin layers 32b and 42d are formed on the annular wall 44, respectively, and the resin layers 42a and 42c are formed on the inner groove 45 of the annular wall 44, respectively. In the brush bristles 51 shown in FIG. 4C, the central resin layer 52a, the outer resin layer 52b, the outer resin layer 52c, the outer resin layer 52d, and the outer resin layer 52d are arranged concentrically. It is formed on a composite fiber 53 composed of an outer resin layer 52e and an outermost resin layer 52f, and the resin layers 52c and 52e are on the annular wall 54, respectively, and the resin layers 52b and 52d are on the inside of the respective annular walls 54. It is formed in the groove 55, and the resin layer 52a in the central portion is formed in the columnar wall 56 in the central portion. In the brush hair material 61 shown in FIG. 4 (D), the brush bristle material 61 is formed of a composite fiber 63 composed of a resin layer 62a in the central portion, a resin layer 62b on the outer side thereof, and a resin layer 62c on the outermost layer, which are arranged concentrically. At the same time, the outermost resin layer 62c is formed on the annular wall 64, the resin layer 62b is formed on the inner groove 65 of the annular wall 64, and the central resin layer 62a is formed on the central columnar wall 66.

Further, in the brush hair material 71 shown in FIG. 5 (A), it is formed on a composite fiber 73 composed of a resin layer 72a in the central portion, a resin layer 72b on the outside thereof, and a resin layer 72c on the outermost layer, which are arranged concentrically. However, the resin layer 72b is formed in a triangular-shaped resin layer, and the resin layer 72b is formed in the annular wall 74, and the central resin layer 72a is formed in the groove 75 inside the annular wall 74. .. In the brush bristles 81 shown in FIG. 5B, the central resin layer 82a, the outer resin layer 82b, the outer resin layer 82c, the outer resin layer 82d, and the most concentrically arranged, the resin layer 82a, the outer resin layer 82b, and the outer resin layer 82d. It is formed on a composite fiber 83 composed of an outer resin layer 82e, but the resin layers 82b and 82d are formed on a resin layer extending in a wavy shape in an annular shape, and these resin layers 82b and 82d are formed on the annular wall 84, respectively. The inner resin layers 82a and 82c are formed in the inner grooves 85 of the respective annular walls 84. In the brush bristles 91 shown in FIG. 5C, the central resin layer 92a, the outer resin layer 92b, the outer resin layer 92c, the outer resin layer 92d, and the most concentrically arranged, the resin layer 92a, the outer resin layer 92b, and the outer resin layer 92d. The composite fibers 93 made of the outer resin layer 92e are formed, and the resin layers 92b and 92d are formed in a petal-like shape in which the thickness of the resin layer changes in the annular extending direction. 92d is formed in the annular wall 94, and resin layers 92a and 92c inside the annular wall 94 are formed in the groove 95 inside the annular wall 94, respectively. In the brush hair material 101 shown in FIG. 5D, the hair material 101 is formed of a composite fiber 103 concentrically arranged, which is composed of a resin layer 102a in the central portion, a resin layer 102b on the outer side thereof, and a resin layer 102c on the outermost layer. However, the cross-sectional shape of the composite fiber 103 and each of the resin layers 102a, 102b, 102c is formed in a hexagonal shape, the outermost resin layer 102c is on the annular wall 104, and the resin layer 102b is inside the annular wall 104. A central resin layer 102a is formed in the groove 105 on the central columnar wall 106.

As described above, the composite fiber having the core-sheath cross-sectional structure composed of a plurality of resin layers in the present invention can take various cross-sectional forms, and can be optimally designed according to the application and purpose of use. is there.

Hereinafter, examples of the present invention will be described.
Examples 1-11, Comparative Example 1
[Making hair materials for brushes]
As raw materials, polybutylene terephthalate (PBT, "Trecon" (registered trademark) 1100SW manufactured by Toray Industries, Inc.), polyethylene terephthalate (PET, manufactured by Toray Industries, Inc., T755M), nylon 610 (Ny610, manufactured by Toray Industries, Inc. "Amilan" (Registered Trademark) CM2001), Thermoplastic Polyamide Elastomer (Ny11-PTMG (Polytetramethylene Glycol), Alchema's "Pevax" (Registered Trademark) 72R53), Polybutylene Naphthalate (PBN, Toyo Spinning Co., Ltd., AE-500) ) Was dried and prepared under the recommended conditions. Table 2 shows the core component, the resin type of the sheath component, the area ratio between the core component and the sheath component, the number of resin layers, and the thickness (representative value) of the resin layers. The composite fiber having the above was melt-spun. The core component referred to here is a component of the resin layer arranged at the center in the cross section of the fiber, and the sheath component is a component of the resin layer arranged at a position other than the center in the cross section of the fiber. The structure of the resin layer in the cross section of the fiber has a structure in which the core component, the sheath component 1, (sheath component 2), the core component, and so on are repeated in order from the center.

After the eluted fibers are cooled and solidified in water, the first stage is stretched 4.5 times in warm water at 60 ° C. and the second stage is stretched 4.5 times in a dry atmosphere at 120 ° C., and then a remittent fever set in a dry heat atmosphere. Was carried out to obtain a core-sheath composite fiber. The composition of the obtained core-sheath composite fiber is shown in Table 2.

The fibers were bundled in a straight line with a bundle diameter of 45 mm, packaged, and then cut to a predetermined length. Next, the bundle of composite fibers was immersed in a heated caustic soda solution with the cut both end faces exposed to dissolve and remove both ends to form an annular wall. By changing the immersion time in the caustic soda solution, the longitudinal length of the portion having the annular wall and the groove was controlled. Table 2 shows the characteristics of the obtained bristle material for brushes.

As Comparative Example 1, PBT fibers were immersed in a caustic soda solution in the same manner as described above to prepare a bristle material for a brush in which both ends were tapered and tapered.

[Making a toothbrush]
The brush hair material obtained by the above method was set in a flat wire type hair transplanter, a predetermined number (about 15 to 40 hairs) was picked, and the hair material was folded in half and driven into the hair transplant hole of the toothbrush head together with the flat line. .. As the toothbrush head, a toothbrush head having a flocked hole with a diameter of 1.5 mm and having a flocked portion of 8 rows and 4 columns was used. Table 2 shows the hair length (mm) and the number of flocked hairs (lines / holes) of the toothbrushes produced in Examples and Comparative Examples.

The following evaluations were performed on each of the obtained toothbrushes, and the results shown in Table 2 were obtained.
[Cleanability evaluation]
An artificial plaque manufactured by Nissin Co., Ltd. was applied to the dentition model and dried for 5 minutes or more. A toothbrush moistened with water was pressed from the upper surface of the dentition model with a force of 230 g, and brushing was performed in the direction along the dentition with a stroke width of 70 mm and a stroke speed of 180 mm / sec. The upper side of the back tooth part of the dentition model was used for evaluation of the tooth surface, and the outer side of the front tooth part was used for evaluation between the teeth. The cleanability was calculated from the number of brushings up to the standard based on the remaining amount of dirt after brushing 20 times with a nylon bristle toothbrush by the following formula.
Cleanability = 20 ÷ (number of brushings to reach the standard)

[Hair opening durability evaluation]
A load of 230 g is applied vertically to the toothbrush from the back side of the sliding surface, and in a state where hot water at 37 ° C is dropped, a stroke width of 70 mm and a stroke speed of 180 mm / sec are applied to the stainless corrugated plate in the longitudinal direction of the toothbrush. The sliding motion was performed 1000 times, and the bristling rate of the brush portion was measured. The method for calculating the hair opening rate was (BA) / A × 100% when the width of the brush portion in the initial state was A mm and the width after sliding was B mm.

[Hair tear durability evaluation]
Under the same conditions as in the evaluation of the hair opening durability, the tearing of the hair tips was observed every 50 times of brushing, and the number of times the number of hair materials in which the hair tears occurred became five.

[Tactile / foaming evaluation]
Twenty adults were asked to use the toothbrush for 30 days, and responses were requested according to the following criteria, and the average score was used as the evaluation value.
Score Tactile foaming 5 Very soft Very good foaming 4 Soft foaming is good 3 Usually neither can be said 2 Hard foaming is bad 1 Very hard Very bad foaming

The present invention can be applied to any brush, and is particularly suitable for toothbrushes, tongue brushes, makeup brushes, application brushes and the like.

1, 21 Brush bristles 2a, 2b, 2c, 2d, 22a, 22b, 22c, 22d Resin layers 3, 23 Composite fibers 4, 24 Cylindrical walls 5, 25 Grooves 6, 26 Cylindrical walls 7, 27 Cylindrical spaces 11 Brush bristle material 12 Toothbrush component 12a Head part front side member 12b Head part back side member 13 Toothbrush 14 Hair planting hole 15 Flat line 16 Through hole 17 Burnt ball 31, 41, 51, 61, 71, 81, 91, 101 Brush Hair materials 32a, 32b, 32c, 42a, 42b, 42c, 42d, 52a, 52b, 52c, 52d, 52e, 52f, 62a, 62b, 62c, 72a, 72b, 72c, 82a, 82b, 82c, 82d, 82e , 92a, 92b, 92c, 92d, 92e, 102a, 102b, 102c Resin layers 33, 43, 53, 63, 73, 83, 93, 103 Composite fibers 34, 44, 54, 64, 74, 84, 94, 104 Circular wall 35, 45, 55, 65, 75, 85, 95, 105 Grooves 56, 66, 106 Cylindrical wall

Claims (8)

A composite fiber extending in the longitudinal direction of the composite fiber at one end or both ends in the longitudinal direction having a core-sheath cross-sectional structure composed of a plurality of resin layers formed of two or more types of resins having different chemical dissolution rates. At least one annular wall extending all around along the outer peripheral surface and inside the annular wall adjacent to the annular wall and extending along the annular wall and recessed in the longitudinal direction of the composite fiber from the tip of the annular wall. A hair material for a brush, characterized in that at least one groove is formed and the number of the plurality of resin layers is in the range of 4 to 6 layers. The hair material for a brush according to claim 1, wherein the thickness of one resin layer in the cross section of the composite fiber is in the range of 10 to 300 μm. The bristles for brushes according to claim 1 or 2 , wherein the length of the composite fiber in the longitudinal direction of the portion having the annular wall and the groove is in the range of 0.5 to 10 mm. The invention according to any one of claims 1 to 3 , which has an opposing wall facing the annular wall with the groove in between, and the height of the composite fiber in the facing wall in the longitudinal direction is higher than the height of the annular wall. Hair material for brushes. The hair material for a brush according to any one of claims 1 to 4 , wherein the at least one annular wall comprises an annular wall extending in a circular shape. The hair material for a brush according to any one of claims 1 to 4 , wherein the at least one annular wall comprises an annular wall extending into a deformed shape other than a circle. The hair material for a brush according to any one of claims 1 to 6 , wherein the plurality of resin layers are provided concentrically. A brush in which at least a part of the brush bristle material according to any one of claims 1 to 7 is used.

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