toothbrush

Abstract

The present invention relates to a toothbrush in which a plurality of bristle bundles, each consisting of 16 branched bristles with 16 branches at the tip, are planted in a first region on the left and right outer sides of the bristle surface of the toothbrush head, and a plurality of bristle bundles, each consisting of 3 branched bristles with 3 branches at the tip, are planted in a second region on the bristle surface inside the first region. The first region may include the region where the outermost rows of bristle bundles at both the left and right ends are planted. The 16 branched bristles have a core-sheath structure consisting of 16 cores and a sheath surrounding them, and have branched portions at the tip that are exposed from the sheath and consist of the 16 cores, and the outer diameter of each core in the core-sheath structure may be 15 to 22 μm.

Description

[Technical Field]

[0001] This invention relates to a toothbrush having branched bristles at the tip. [Background technology]

[0002] Conventionally, toothbrushes in which filaments with multiple branched and tapered tips are embedded in the brush portion are known to have excellent interdental penetration, a high cleaning sensation, and to be less likely to cause irritation to the gums because the branched tips become softer (Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2001-169827 [Patent Document 2] Japanese Patent Publication No. 2003-199626 [Overview of the project] [Problems that the invention aims to solve]

[0004] In particular, filaments with three branched tips (trifugal bristles) are considered to be superior in cleaning tooth surfaces and interdental spaces because they allow for easier application of pressure to the cleaning surface. However, during their research, the inventors discovered that when brushing teeth with a toothbrush equipped only with trifugal bristles, the tips of the bristle bundles, when they touched the gums, did not provide a soft sensation for reasons unknown, and some people tended to experience pain.

[0005] Therefore, in view of the above-mentioned circumstances, the present invention aims to provide a toothbrush that is gentle on the gums and has excellent cleaning properties. [Means for solving the problem]

[0006] In view of the current situation, the inventors of the present invention have conducted diligent studies and have found that the above problem can be solved by implanting multiple hair bundles consisting of 16-branched hairs, each with a tip branched into 16 strands, in a first region on the left and right outer sides of the hair implantation surface of the head portion where multiple hair bundles are implanted, and by implanting multiple hair bundles consisting of 3-branched hairs, each with a tip branched into 3 strands, in a second region inside the first region, thereby completing the present invention.

[0007] In other words, the present invention encompasses the following inventions. (1) A toothbrush in which, in a first region on the left and right outer sides of the bristle surface of the head portion on which multiple bristle bundles are planted, multiple bristle bundles consisting of 16-branched bristles with 16 branches at the tip are planted, and in a second region on the bristle surface inside the first region, multiple bristle bundles consisting of 3-branched bristles with 3 branches at the tip are planted. (2) The toothbrush according to (1), wherein the first region includes the region in which the outermost rows of bristles at both the left and right ends are erected. (3) The 16 branched hairs have a core-sheath structure consisting of 16 cores and a sheath surrounding them, and the tip has a branched portion consisting of the 16 cores exposed from the sheath, The toothbrush according to (1) or (2), wherein the outer diameter of each core portion of the core-sheath structure is 15 to 22 μm. (4) When the entire bundle of bristles in the head section is pressed at a constant speed of 0.1 mm / min along the direction of protrusion of the bristles, from the tip to the base, until the amount of indentation is 1 mm, the maximum value of the average pressure is 400 g / cm². 2 The toothbrush described in any of (1) to (3) above. (5) When the entire bundle of hair in the head is pressed at a constant speed of 0.1 mm / min along the direction of the protrusion of the hair bundle, from the tip to the base, until the amount of indentation is 1 mm, the maximum value of the average pressure is defined as P1. When the hair in all of the multiple bundles of hair implanted in the head is 16-branched, and the same pressing is applied, the maximum value of the average pressure is defined as P0. If the value of P1 is 60 g / cm² higher than the value of P0, 2 A toothbrush as described in any of (1) to (4) above, which results in the following increase. [Effects of the Invention]

[0008] Since the toothbrush of the present invention has a soft texture on the gums, it is difficult to feel pain even when brushing at a position where the tip of the bristle bundle hits the gums during toothbrushing. Also, due to its excellent cleaning ability, it can efficiently remove tooth stains on tooth surfaces, between teeth, tooth necks, etc.

Brief Description of the Drawings

[0009] [Figure 1] Figure 1(a) is an explanatory diagram showing a toothbrush according to a representative embodiment of the present invention, and Figure 1(b) is an enlarged view of the tip portion of the filaments constituting the bristle bundle. [Figure 2] Cross-sectional view of a 16-branched bristle. [Figure 3] Enlarged view of the tip portion of a 16-branched bristle. [Figure 4] Cross-sectional view of a 3-branched bristle. [Figure 5] Explanatory diagram showing the structure of each part of the toothbrushes of Examples 1 to 3 and Comparative Examples 1 to 4, and the results of the softness test of Test Example 1. [Figure 6] Explanatory diagram of the embodiment of the softness test of Test Example 1. [Figure 7] Explanatory diagram of the pressing surface of the toothbrush. [Figure 8] Schematic diagram of an image showing the measurement results of the softness test obtained in Test Example 1. [Figure 9] Explanatory diagram of the embodiment of the durability (slip resistance) test of Test Example 2. [Figure 10] Graph showing the results of the durability (slip resistance) test in Test Example 2. [Figure 11] Explanatory diagram of the embodiment of the durability (bristle tip splitting) test in Test Example 3. [Figure 12] Figures 12(a) and 12(b) are explanatory diagrams showing other embodiments of the present invention.

Modes for Carrying Out the Invention

[0010] Next, embodiments of the present invention will be described in detail based on the accompanying drawings.

[0011] As shown in Figure 1(a), a toothbrush 1 according to a representative embodiment of the present invention comprises a head portion 2 having a bristle base 20 on which a plurality of bristle bundles 10 are planted, and a handle body 3. As shown in Figure 1(b), on the bristle surface 20a of the bristle base 20, a plurality of bristle bundles 10a consisting of 16-branched bristles 4 with 16 branches at the tip are planted in the first regions R11 and R12 on the left and right outer sides, and a plurality of bristle bundles 10b consisting of 3-branched bristles 5 with 3 branches at the tip are planted in the second region R2 which is inside the first regions R11 and R12.

[0012] In this invention, "left-right direction" refers to the direction that intersects approximately perpendicularly with the axial direction X of the toothbrush 1. When the implantation surface 20a is facing outwards, the right side is referred to as "right" and the left side as "left" with respect to the axial direction X. The tip side of the toothbrush 1 is also referred to as "up," and the rear end side of the toothbrush 1 is also referred to as "down."

[0013] According to the toothbrush 1 of the present invention, as shown in Figures 2 and 3, the core portion 6a that constitutes the tip of the 16-branched bristles 4 is thin in diameter and soft, so the pressure applied when the surfaces of the bristle bundles 10a and 10b are pressed against the tooth surface is distributed. Since these 16-branched bristles 4 are arranged in the first regions R11 and R12 located on the left and right outer sides of the bristle implantation surface 20a, when brushing teeth, the feeling is softer even when the tip of the brush touches the gums, which has the advantage of making it less likely to cause pain. Furthermore, in the toothbrush 1 according to the present invention, as shown in Figure 4, three-branched bristles 5 with a larger diameter of core portion 6b than the 16-branched bristles 4 are arranged in the second region R2, which is inside the first regions R11 and R12, thus exhibiting higher cleaning power than the 16-branched bristles 4. For this reason, in addition to being able to easily come into contact with dirt on the tooth surface, between teeth, and on the gums, dirt on the tooth surface, between teeth, and on the gums can be removed efficiently.

[0014] In the present invention, the head portion 2 is molded together with the handle body 3 from a rigid synthetic resin such as polyacetal resin (POM), polybutylene terephthalate resin (PBT), or polyamide resin.

[0015] Furthermore, the body of the toothbrush 1 may be integrally molded using two types of resin materials, and may include a base material made of a first resin material having a head portion 2 equipped with a bristle base, a neck portion, and a handle base material portion, and a covering portion made of a second resin material covering a part of the handle base material portion. The first resin material constituting the base material is not particularly limited as long as it is a hard thermoplastic resin that can withstand the external force acting during brushing, but a hard resin mainly composed of a resin selected from polybutylene terephthalate resin, polypropylene terephthalate resin, polyethylene terephthalate resin, polyethylene naphthalate resin, polyester resin, polyacetal resin, polycarbonate resin, and polyamide resin is used. Here, "main component" refers to a resin that is included in a proportion of 50% by weight or more when used as a blend or alloy with other resins, or a copolymer with other resins in which repeating polymer units of the resin are included in a proportion of 50% by weight or more. In particular, it is preferable to use polyacetal resin or polyamide resin, which have excellent mechanical strength, in order to make the bristle base 20 of the head part 2 thin-walled and improve the cleaning performance of hard-to-reach areas such as the back surface of molars. The coating portion is composed of a second resin material of a different material from the first resin material that constitutes the base material. While hard thermoplastic resins such as polybutylene terephthalate resin and polyethylene terephthalate resin (polypropylene terephthalate resin) can be used as the second resin material constituting the coating portion, a soft thermoplastic resin such as a thermoplastic elastomer is preferably used to obtain an anti-slip function from the coating portion. Specifically, thermoplastic elastomers such as polystyrene-based thermoplastic elastomers, polyolefin-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, 1,2-polybutadiene-based thermoplastic elastomers, ethylene-vinyl acetate-based thermoplastic elastomers, polyvinyl chloride-based thermoplastic elastomers, natural rubber-based thermoplastic elastomers, fluororubber-based thermoplastic elastomers, trans-polyisoprene-based thermoplastic elastomers, and chlorinated polyethylene-based thermoplastic elastomers can be used. be.

[0016] The size, shape, thickness, etc. of the head portion 2 and the shape, structure, etc. of the handle body 3 can be the same as those of a known toothbrush, and there are no particular limitations. For example, the shape of the head portion 2 may be such that the tip is tapered to the rear end, as shown in Examples 1(b) and 5, Examples 1 and 2, or the width of the planting surface 20a may be approximately the same from the tip to the rear end, as shown in Example 3 of Figure 5.

[0017] The thickness of the bristle base 20, the diameter and depth of the bristle holes provided on the bristle surface 20a, the number of bristle holes, and their arrangement are set appropriately according to the target user. For example, the thickness of the bristles implantation base 20 can be appropriately determined, ranging from approximately 2.5 to 5.0 mm. The opening diameter (hole diameter) of the bristles implantation hole can be appropriately determined, ranging from approximately 1.0 to 2.5 mm. The depth of the bristles implantation hole can be determined within the range of 1.5 to 3.5 mm.

[0018] In the present invention, the first region R11 of the bristled surface 20a refers to the region that includes the bristle bundles 10 erected in the outermost row in the vertical direction on the left end side of the bristled surface 20a. The first region R12 of the grafted surface 20a refers to the region that includes the bristle bundles 10 erected in the outermost row in the vertical direction on the right end side of the grafted surface 20a.

[0019] The 16 branched hairs 4 planted in the first regions R11 and R12 have a core-sheath structure 8a consisting of 16 cores 6a and a surrounding sheath 7a, as shown in Figure 2, and have branched sections 9a made up of the 16 cores 6a exposed from the sheath 7a at the tip of the hair, as shown in Figure 3.

[0020] At the branching point 9a of the 16-branched bristles 4, 16 thin core parts 6a are exposed. When the bristles are pressed against teeth, gums, etc., the exposed core parts 6a at the tip of the branching point 9a flexibly deform, thereby achieving a soft touch. The core portions 6a of the branched portion 9a may be fixed together by the resin constituting the sheath portion 7a, or each or a part of each core portion 6a may be separated.

[0021] The outer diameter L1 (also called the hair diameter) of the 16-branched hair 4 should be in the range of 160 to 210 μm. The outer diameter L2 of the core portion 6a is set to 15-22 μm, which allows for a lower pressing force, resulting in a soft texture and excellent durability even after repeated brushing. By adjusting the minimum wall thickness L3 of the sheath portion 7a constituting the core sheath structure 8a to 26 μm or more, wear and tear of the sheath portion 7a caused by repeated brushing can be suppressed, thereby maintaining the durability of the 16-branched bristles 4. In Figures 1(a), 1(b), and 2, the core portion 6a, sheath portion 7a, and 16 branched bristles 4 are all depicted as circular in shape, but this is not the only option. Various shapes can be used, such as elliptical or polygonal shapes, as long as they do not have any recesses where dirt may accumulate.

[0022] The tip shape of the core portion 6a exposed at the branching portion 9a may be any shape, such as a tapered shape, a substantially flat shape, or a shape with fine irregularities. Furthermore, the tips of each core portion 6a may be aligned or not, or they may be inclined, for example, as shown in Figure 3, with the length of each core portion 6a varying toward one end. The length L4 of the core portion 6a exposed from the tip of the branched portion 9a should be adjusted to a range of at least 0.01 to 1.2 mm, or 0.05 to 1.0 mm, during use. Furthermore, the length of the 16 branched bristles 4 erected on the surface of the bristle base 20 can be within the same range as that of a commercially available toothbrush, and there are no particular limitations. Furthermore, the lengths of the hair bundles 10a planted in the multiple planting holes of the hair implantation base 20 may be uniform or may have differences in length. The difference in hair length between the hair bundles 10a should be adjusted to a range of 0 to 2.0 mm.

[0023] In the bristled surface 20a, a tri-branched bristle 5 is implanted in the second region R2 located inside the first regions R11 and R12. As shown in Figure 4, this tri-branched bristle 5 has a core-sheath structure 8b consisting of three core portions 6b and a surrounding sheath portion 7b, and has a branched portion (not shown) at the tip of the bristle that is exposed from the sheath portion 7b and consists of the three core portions 6b. The diameter of the three exposed core portions 6b at the branching point of the three branched bristles 5 is larger than that of the core portion 6a of the sixteen branched bristles 4. Therefore, by positioning the three branched bristles 5 in the second region R2, they can exert pressure when pressed against teeth or gums, resulting in excellent cleaning performance. The space between each core portion 6b of the branched bristles 5 may be fixed by the resin constituting the sheath portion 8b, or each or part of each core portion 6b may be separated.

[0024] The outer diameter L1 (also called the hair diameter) of the three-branched hair 5 should be in the range of 160 to 210 μm. The outer diameter L2 of the core portion 6b can be 30 to 50 μm.

[0025] The tip shape of the core portion 6b exposed at the branching point of the three-branched bristles 5 can be any shape, such as a tapered shape, a nearly flat shape, or a shape with fine irregularities. Also, the tips of each core portion 6b may or may not be aligned. The length of the core portion 6b exposed from the tip at the branched section should be adjusted to a range of at least 0.1 to 1.0 mm during use. Furthermore, the length of the three-branched bristles 5 erected on the surface of the bristle base 20 can be within the same range as that of commercially available toothbrushes, and there are no particular limitations. Furthermore, the lengths of the hair bundles 10b planted in the multiple planting holes of the hair implantation base 20 may be uniform or may be uneven. The difference in hair length between the hair bundles 10b should be adjusted to a range of 0 to 2.0 mm.

[0026] Furthermore, the lengths of the hair bundles 10a and 10b planted in the multiple planting holes of the hair implantation base 20 may be the same or there may be differences in length. The difference in hair length between hair bundles 10a and 10b should be adjusted to a range of 0 to 2.0 mm.

[0027] The 16-branched bristles 4 and 3-branched bristles 5 used in the present invention can be manufactured by known methods. For example, as described in Japanese Patent Application Publication No. 2010-82094, the core portions 6a and 6b and the sheath portions 7a and 7b are both made of chemically soluble synthetic resins, the synthetic resin of the core portions 6a and 6b is a resin that dissolves more slowly in chemical solution than the synthetic resin of the sheath portions 7a and 7b, and a branched portion is formed at least at one end, consisting of the core portions 6a and 6b exposed from the sheath portions 7a and 7b by a chemical dissolution treatment. However, there are no particular limitations on the manufacturing method.

[0028] The synthetic resins constituting the core portions 6a and 6b and the sheath portions 7a and 7b can be polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), polyester elastomer, or mixtures thereof, which can be used in appropriate combinations depending on their solubility in the chemical solution. For example, in the case of polyester resin, an alkaline dissolving solution such as an aqueous solution of caustic soda can be used. Alternatively, the core portions 6a and 6b and the sheath portions 7a and 7b can be made of a combination of polyamide resins, and the branched portion can be created using an acidic dissolving solution. It is also possible to use combinations of other chemically soluble resins.

[0029] In the hair implantation holes of the first regions R11 and R12, hair bundles 10a consisting of 16-branched hairs 4 are implanted. However, if the effects of the present invention can be achieved, hair bundles consisting of branched hairs other than 16-branched hairs 4 may be implanted in a portion of the hair implantation holes. In this case, it is preferable to adjust the proportion of hair bundles 10a consisting of 16-branched hairs 4 implanted in the hair implantation holes of the first regions R11 and R12 to be 80% or more. There are no particular limitations on branched hairs other than the 16 branched hairs mentioned above, but from the viewpoint of maintaining a soft texture, branched hairs with more than three core strands are also acceptable.

[0030] In the hair implantation holes of the second region R2, hair bundles 10b consisting of trifoliate hairs 5 are implanted. However, hair bundles consisting of branched hairs other than trifoliate hairs 5 may be implanted if the effects of the present invention can be achieved. In this case, the proportion of hair bundles 10b consisting of trifoliate hairs 5 implanted in the hair implantation holes of the second region R2 is preferably adjusted to 50% or more, and more preferably to 55% or more. There are no particular limitations on branched hairs other than 3-branched hairs; 16-branched hairs are also acceptable, or for example, branched hairs with 10 or fewer core strands are also acceptable.

[0031] Regarding the method of implanting filaments such as 16-branched hairs 4 and 3-branched hairs 5, conventional methods can be widely used. For example, a method can be used in which 10 to 40 filaments are bundled together, a flat wire is pressed against the center, and the filament bundle is driven into the implantation hole while deforming it into a U-shape. Alternatively, a method can be used in which the base end of the filament is melted and embedded and joined into the implantation hole without using such a flat wire.

[0032] The toothbrush 1 according to the present invention, having the above configuration, achieves both softness of the bristle tips against the gums and excellent cleaning performance.

[0033] The softness of the feel against the gums can be evaluated, for example, as shown in Figure 6, by the maximum value of the average pressure when the entire bristle bundle 10 of the head portion 2 is pressed at a constant speed of 0.1 mm / min along the protruding direction of the bristle bundle 10, from the tip to the base, until the amount of indentation is 1 mm. In the toothbrush 1 according to the present invention, the maximum pressure value is set to 400 g / cm², from the viewpoint of easily achieving the effects of the present invention. 2 The following is preferable: In the toothbrush 1 according to the present invention, the maximum pressure value is 400 g / cm². 2 Because it is adjusted as follows, it has the advantage of making it less likely to cause pain even if the tip of the bristles touches the gums while brushing your teeth. The method for measuring the average pressure value and its maximum value can be carried out in accordance with the method described in the embodiments below.

[0034] Furthermore, in order to more easily achieve the effects of the present invention, the toothbrush 1 according to the present invention is configured such that the entire bundle of bristles 10 of the head portion 2 is pressed at a constant speed of 0.1 mm / min along the protruding direction of the bundle of bristles 10, from the tip to the base, until the amount of indentation is 1 mm, and the maximum value of the average pressure is defined as P1. When all the hairs in the multiple hair bundles implanted in the head portion are 16-branched hairs, and the same pressure is applied, the maximum value of the average pressure when the same pressure is applied is defined as P0. The value of P1 is 60 g / cm³ higher than the value of P0. 2It is preferable that the following increases be made.

[0035] Although embodiments of the present invention have been described above, the present invention is not limited in any way to these examples, and can be implemented in various forms without departing from the spirit of the invention. For example, the shape of the toothbrush 1 shown in Figures 1(a) and 1(b) is just one example and is not limited to this; it can take various shapes. Also, although Figures 1(a) and 1(b) show a manual toothbrush, the present invention is not limited to a manual toothbrush; it may also be an electric toothbrush in which a toothbrush cleaning body having the head portion described above is connected to the tip of the main body which serves as a gripping part containing a drive mechanism, or it may take other forms as well. Furthermore, various arrangements of the bristle holes on the bristle surface 20a can be adopted. In addition, there are no particular limitations on the number of filaments constituting the bristle bundle 10, the number of bristle holes, or the arrangement of the bristle bundle 10.

[0036] For example, other embodiments of the arrangement of hair bundles 10 on the hair implantation surface 20a include those shown in Figures 12(a) and 12(b). In Figure 12(a), the hair bundles 10 are arranged in eight rows vertically, with a total of 33 hair bundles 10 implanted: 2 in the first row, 3 in the second row, 4 in the third row, 5 in the fourth to seventh rows, and 4 in the eighth row. In the first regions R11 and R12, located on the left and right outer sides of the first to eighth rows, 8 hair bundles 10a, each consisting of 16 hairs, are implanted, for a total of 16 bundles. In the second region R2, located inside the first regions R11 and R12, a total of 13 hair bundles 10b, each consisting of 3-branched hairs, are placed in the center of the second to sixth rows and the seventh row, while a total of 4 hair bundles 10a, each consisting of 16 hairs, are placed on the left and right outer sides of the seventh row and in the center of the eighth row, which also constitute the second region R2. Furthermore, as shown in Figure 12(b), the hair bundles 10 are arranged in 8 rows vertically and 6 rows horizontally, with a total of 44 hair bundles 10 implanted: 4 in the first row vertically, 6 in the second to seventh rows, and 4 in the eighth row. In the first, second, fifth, and sixth rows horizontally, including the first regions R11 and 12 from the left and right outer edges, a total of 28 hair bundles 10a consisting of 16-branched hairs 4 are arranged, and in the third and fourth rows horizontally, a total of 16 hair bundles 10b consisting of 3-branched hairs 5 are arranged. With the toothbrush shown in Figures 12(a) and 12(b), the texture against the gums is soft, so even when brushing with the tips of the bristle bundles 10 touching the gums, it is less likely to cause pain. Furthermore, because it has excellent cleaning properties, it can efficiently remove plaque from the tooth surface, between teeth, and around the gums. [Examples]

[0037] For brush filaments (hair diameter (L1): 170 μm), we prepared 16-branched filaments, 3-branched filaments, and saturated polyester bristles. The composition of each filament is as follows: • 16-branched filament (16 strands) Core 6a: Made of polyamide resin (nylon), Sheath part 7a: Made of polyester resin (polybutylene terephthalate), Outer diameter (L2) of core 6a: 11 μm, 15 μm, 18 μm, 22 μm, 26 μm; Total cross-sectional area ratio of core 6a: 6.7%, 12.5%, 17.9%, 26.8%, 37.4% Sheath wall thickness (L3): 42.5 μm, 37 μm, 32 μm, 27 μm, 21 μm Branch section 9a (hair length) length (L4): 0.4 mm • 3-branched filament (3 strands) Core 6b: Made of polyamide resin (nylon), Sheath part 7b: Made of polyester resin (polybutylene terephthalate), Outer diameter (L2) of core 6b: 34 μm, Total cross-sectional area ratio of core 6b: 12.0% Sheath wall thickness (L3): 42.5 μm Branching section (bristle length): 0.5 mm Furthermore, when implanting the 16-branched and 3-branched filaments onto the filament implantation base 20, the ends of each filament were chemically dissolved to form a branched section with an exposed core.

[0038] The outer diameter (L2) of the core sections 6a and 6b, the cross-sectional area (L2) of the core sections 6a and 6b, and the wall thickness (L3) of the sheath sections 7a and 7b are average values ​​obtained by arbitrarily selecting 10 filaments of each type, cutting them perpendicular to the axial direction, and observing the cross-sectional state using a Keyence VHX6000 digital microscope. The results are shown in Table 1.

[0039] [Table 1]

[0040] (Example 1) As shown in Figures 1(a), 1(b), and 5, a toothbrush 1A equipped with a head portion 2 in which the shape of the bristle surface 20a tapers was manufactured by a known method. As the filament material for the brush bristles, the aforementioned 16-branched bristles (core outer diameter (L2) 18 μm) and the aforementioned 3-branched bristles were used. In addition, as shown in Figure 5, a bristle base 20 having 35 bristle implantation holes with a diameter of 1.4 mm was used. Many of the above filament materials were bundled together, the cores at both ends were exposed by chemical dissolution, then folded in half, and the filaments were implanted into each filament hole using a flat wire. The components of toothbrush 1A are as follows: Head length: 26.2mm Handle length: 180mm Hair bundle length: 11.2mm Head section 2, bristle base 20 thickness (base thickness): 3.5 mm Diameter of the hair implantation hole: 1.4 mm Pitch between hair implantation holes (hole pitch): 1.05 mm Number of hair transplant holes: 35 Hair diameter: 170 μm for both 16-branched and 3-branched hair filaments. The conditions for each part are shown in Figure 5.

[0041] In toothbrush 1A, a bundle of 16 branched bristles 10a is implanted in eight bristle holes in the first region R11 on the left outer side of the bristle surface 20a, and in eight bristle holes in the first region R12 on the right outer side. In the second region R2, which is located inside the first regions R11 and R12 of the bristled surface 20a, bundles of hair 10b consisting of three-branched hairs 5 are implanted in 11 bristled holes on the tip side, and bundles of hair 10a consisting of sixteen-branched hairs 4 are implanted in 8 bristled holes on the rear end side of the second region R2.

[0042] (Example 2) As shown in Figure 5, toothbrush 1B was fabricated in the same manner as in Example 1, except that bristle bundles 10b consisting of three-branched bristles 5 were implanted in all (19) bristle implantation holes in the second region R2.

[0043] (Example 3) As shown in Figure 5, a toothbrush 1C was manufactured in the same manner as in Example 1, except that it had a head portion 2 in which the width of the implanting surface 20a was substantially the same from the tip to the rear end. The configuration of the head part 2 of toothbrush 1C, which differs from toothbrush 1A, is as follows. Hair flocking base 20 thickness (base thickness): 4.0 mm Diameter of the hair implantation hole: 1.5 mm Pitch between hair implantation holes (hole pitch): 1.15 mm Number of hair transplant holes: 30

[0044] In toothbrush 1C, the bristle bundles 10 are arranged in four rows from the tip to the rear end, and the bristle bundles 10a, each consisting of 16 branched bristles 4, are implanted in seven bristle holes in the first region R11 on the left outer side of the bristle surface 20a, and in seven bristle holes in the first region R12 on the right outer side. In the second region R2 of the grafted surface 20a, which is inside the first regions R11 and R12, bundles of hair 10b, each consisting of a trifurcated hair 5, are implanted in 16 hair implantation holes arranged in two rows.

[0045] (Comparative Example 1) As shown in Figure 5, a toothbrush 1D was fabricated in the same manner as in Example 1, except that a bundle of bristles 10b consisting of three-branched bristles 5 was implanted in all of the bristles (35 in total) of the implantation holes.

[0046] (Comparative Example 2) As shown in Figure 5, a toothbrush 1E was fabricated in the same manner as in Example 1, except that a bundle of bristles 10a consisting of 16 branched bristles 4 was implanted in all of the bristles (35 in total).

[0047] (Comparative Example 3) As shown in Figure 5, toothbrush 1F was manufactured in the same manner as in Example 3, except that a bundle of bristles 10a consisting of 16 branched bristles 4 was implanted in all (30) of the bristle implantation holes.

[0048] (Comparative Example 4) As shown in Figure 5, toothbrush 1G was manufactured in the same manner as in Example 3, except that bristle bundles made of saturated polyester bristles were planted in 16 bristle holes in the second region R2, which is inside the first regions R11 and R12 of the bristle surface 20a.

[0049] (Test example 1: Softness test) As shown in Figure 6, a sheet-type surface pressure gauge 12a (manufactured by Nitta Corporation, approximately 5.0 cm x 5.0 cm) was installed on the top surface of a roughly cubic metal base 11 (length: approximately 10 cm, width: approximately 10 cm, height: approximately 10 cm).

[0050] Next, the entire bundle of bristles 10 of the head portion 2 of the toothbrush 1A to 1G was brought into contact with the surface of the sheet-like surface pressure gauge 12a, and the maximum value of the pressure P (g) was measured when pressure was applied at a constant speed of 0.1 mm / min along the protruding direction of the bristles 10, from the tip to the base, until the indentation amount was 1 mm.

[0051] To determine the pressure value, the area of ​​the pressing surface of the head part 2 (cm²) 2 The following was calculated: That is, as shown in FIG. 7, the area of the pressing surface 16 formed so as to contact the outer edge of the hair implantation hole was measured so that all the hair implantation holes of the hair bundles 10 implanted in the head portion 20 of the toothbrush 1A were included. For the pressing surface 16 of the head portion 2 having the shape of Examples 1 and 2 and Comparative Examples 1 and 2, the area was 1.62 cm 2 For the pressing surface 16 of the head portion 2 having the shape of Example 3 and Comparative Examples 3 and 4, the area was 1.65 cm 2 The maximum value (g / cm per pressing surface 16) of the pressure value was calculated by measuring multiple times. The results are shown in FIG. 5. 2 ) was calculated. The results are shown in FIG. 5.

[0052] Also, the difference (=P0 - P1) between the maximum value (P0) of the average pressure value of Comparative Example 2 in which all the hairs of the hair bundle 10 of the head portion 2 are 16-branched hairs 4 and the maximum value (P1) of the average pressure value of Examples 1 and 2 was described in FIG. 5 as the relative value of the pressure. Similarly, the difference (=P0 - P1) between the maximum value (P0) of the average pressure value of Comparative Example 3 in which all the hairs of the hair bundle 10 of the head portion 2 are 16-branched hairs 4 and the maximum value (P1) of the average pressure value of Examples 3 and Comparative Example 4 was described in FIG. 5 as the relative value of the pressure.

[0053] ? Also, FIG. 8 shows a schematic diagram of an image showing the pressurized state measured by the sheet-like surface pressure gauge 12a.

[0054] From the results shown in FIG. 5, for the toothbrushes 1A, 1B, and 1C of Examples 1 to 3, the maximum value of the average pressure value per pressing surface was 400 g / cm 2 or less. On the other hand, for the toothbrush 1D of Comparative Example 1 composed only of the hair bundle 10b made of the 3-branched hair 5 and the toothbrush 1G of Comparative Example 4 in which the second region R2 was made of saturated polyester hair, the maximum value of the average pressure value per pressing surface exceeded 400 g / cm 2 .

[0055] Also, for the toothbrushes 1A, 1B, and 1C of Examples 1, 2, and 3, the relative value of the maximum value of the average pressure value with respect to the toothbrush 1E of Comparative Example 2 composed only of the hair bundle 10a made of the 16-branched hair 4 and the toothbrush 1F of Comparative Example 3 was 60 g / cm 2As follows, while it possesses a softness similar to a toothbrush composed solely of 16-branched bristles 4, the relative values ​​for toothbrush 1D of Comparative Example 1, which is composed solely of bristle bundles 10b consisting of 3-branched bristles 5, and toothbrush 1G of Comparative Example 4, in which the second region R2 is composed of saturated polyester bristles, are 90 g / cm³. 2 It exceeded [a certain limit] and had a hard texture.

[0056] In fact, the image results shown in Figure 8 show that in Comparative Example 4, a large pressure is generated near the second region R2 where saturated polyester fibers are placed.

[0057] When brushing was performed in the mouth using toothbrushes 1A to 1C from Examples 1 to 3 and toothbrushes 1E and 1F from Comparative Examples 2 and 3, it was confirmed that in all cases, the tips of the bristle bundles 10 felt soft when they touched the gums, and pain in the gums was less likely to be felt. On the other hand, when brushing was performed in the same manner using toothbrush 1D of Comparative Example 1 and toothbrush 1G of Comparative Example 4, a hard sensation was felt when the tip of the bristle bundle 10 touched the gums. Therefore, in the toothbrush 1 of the present invention, the maximum value of the average pressure measured by the method described in Test Example 1 is 400 g / cm². 2 The following adjustments have been made, and the P1 value is 60 g / cm³ higher than the P0 value. 2 It can be seen that the soft texture is achieved by adjusting the following increases.

[0058] (Test Example 2: Durability (Slipperiness) Test) Five types of toothbrushes were prepared in the same manner as in Example 3, except that the 16-branched bristles 4 used had core outer diameters (L2) of 11 μm, 15 μm, 18 μm, 22 μm, and 26 μm, as shown in Table 1.

[0059] The handle 3 of the toothbrush 1 was fixed at the finger rest (not shown), and as shown in Figure 9, the entire bundle of bristles 10 of the head 2 of the toothbrush 1 was brought into contact with the surface of the measuring instrument 13 (tribogear tactile meter TYPE33, Shinto Kagaku Kagaku Co., Ltd.). The vertical load applied along the protruding direction of the bristles 10, from the tip to the base, was adjusted to 0.5, 1.0, 1.5, 2.0, and 3.0 N, and the toothbrush 1 was moved back and forth to measure the frictional force and coefficient of friction (μ). The frictional force and coefficient of friction were measured according to the manual attached to the measuring instrument 13. The above experiment demonstrates that a higher coefficient of friction results in less slipping, while a lower coefficient of friction results in easier slipping. The results are shown in the graph in Figure 10. From the graph in Figure 10, in a toothbrush 1 in which a bundle of 16 branched bristles 10a is planted in the first region R11 and 12 of the bristle surface 20a of the head portion 2, and a bundle of 3 branched bristles 5 is planted in the second region R2 of the bristle surface 20a, the coefficient of friction at low load was greatest when the outer diameter of the core was 11 μm. Therefore, it was inferred that when the outer diameter of the core of the 16 branched bristles is 11 μm, the tip becomes too soft, and the sheath portion, which is larger in outer diameter and harder than the core, is more likely to come into contact with the teeth and gums. Therefore, in the toothbrush 1 according to the present invention, by making the outer diameter of the core of the 16-branched bristles 4 15 μm or more, it is possible to easily feel the softness when the tip of the bristle bundle 10 touches the teeth and gums.

[0060] (Test Example 3: Durability (Splitting of Bristle Tips) Test) Five types of toothbrushes 1, each with 16 branched bristles and a core outer diameter (L2) of 11 μm, 15 μm, 18 μm, 22 μm, and 26 μm, as prepared in Test Example 2, were used.

[0061] As shown in Figure 11, a water tank 14 of a predetermined size was prepared, filled with water at 37±1℃, and a corrugated sheet 15 (made of polyacetal (POM) resin) was submerged in the tank. Next, the toothbrush 1 was placed in the water of the tank 14, and the entire bundle of bristles 10 of the head portion 2 of the toothbrush 1 was brought into contact with the surface of the corrugated sheet 15. The load applied vertically from the tip to the base of the bundle of bristles 10, along the direction of protrusion of the bundle of bristles 10, was adjusted to 300g, and in that state, the toothbrush 1 was moved back and forth 1000 times at a speed of 30 rpm. Next, the condition of the area around the branching portion 9a of the 16-branched hair 4 after 1000 sliding cycles was observed, and the length (L4) of the branching portion 9a was measured, as well as the difference in length before and after sliding (=(L4 after sliding) - (L4 before sliding)). The results obtained are shown in Table 2.

[0062] [Table 2]

[0063] As shown in the results in Table 2, when the outer diameter of the core was 26 μm, the sheath portion 7a split and each core portion separated, resulting in a significantly longer branching portion 9a. Therefore, it can be seen that the durability of the toothbrush 1 according to the present invention can be further improved by adjusting the outer diameter of the core of the 16-branched bristles 4 to 22 μm or less.

[0064] (Test Example 4: Cleanability Evaluation Test) The toothbrushes 1A, 1B, 1D, and 1E obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were subjected to cleaning performance evaluation tests. For the cleaning performance evaluation test, artificial plaque was applied to a jaw model, and a robot was equipped with toothbrush 1 (1A, 1B, 1D, 1E) to brush five tooth surfaces from tooth #3 to #7 of the jaw model (gingival recession model) for 3 seconds per tooth, with an average brushing pressure of 150g, a stroke of 20mm, and a speed equivalent to 150rpm. After brushing, the percentage of artificial plaque removed from the interdental spaces, tooth surfaces, and cervical areas was calculated. The results are shown in Table 3.

[0065] [Table 3]

[0066] As shown in Table 3, the toothbrushes 1A and 1B of Examples 1 and 2 demonstrated excellent cleaning performance, with a cleaning efficiency on the tooth surface, interdental spaces, and gingival margins comparable to that of toothbrush 1D (Comparative Example 1), which consisted solely of three-branched bristles 5. In particular, toothbrushes 1A and 1B of Examples 1 and 2 demonstrate excellent cleaning performance of the tooth surface. On the other hand, toothbrush 1E, which consisted only of 16-branched bristles 4 as in Comparative Example 2, had a low removal rate and poor cleaning performance in all areas, including the tooth surface, interdental spaces, and cervical area.

[0067] (Comparative Example 5) A toothbrush was fabricated in the same manner as in Example 2, except that the diameter of the bristle implantation hole was changed to 1.5 mm and saturated polyester bristles were implanted in the second region R2 instead of the three-branched bristles 5.

[0068] Using toothbrush 1 obtained in Comparative Example 5, a cleaning power evaluation test was conducted according to Test Example 4. The results are shown in Table 4.

[0069] [Table 4]

[0070] As shown in Table 4, in Comparative Example 5, saturated polyester bristles were implanted in the second region R2, resulting in increased pressure and improved cleaning performance. However, when brushing with the prescribed force, the tips of the bristles felt hard against the gums, and sometimes I experienced severe pain in my gums while brushing. [Explanation of Symbols]

[0071] 1. Toothbrush 2 Head section 3 Handle body 4 16 branched hairs 5. Three-branched hair 6a, 6b core 7a, 7b Scabbard part 8a, 8b Core sheath structure 9a Branch 10, 10a, 10b hair bundles 11. Base 12a Sheet-type surface pressure gauge 13 Measuring equipment 14 Aquariums 15 corrugated sheets 16 Pressing surface 20 Hair implantation stand 20a Hair implantation surface R11, R12 1st area R2 2nd area

Claims

1. In the first region on the left and right outer sides of the head portion where multiple hair bundles are implanted, multiple hair bundles consisting of 16-branched hairs, each with a tip that branches into 16 strands, are implanted. Furthermore, a toothbrush in which multiple bundles of bristles, each having a tip that branches into three, are planted in a second region located inside the first region of the bristle surface.

2. The toothbrush according to claim 1, wherein the first region includes regions where the outermost rows of bristles at both the left and right ends are erected.

3. The 16 branched hairs have a core-sheath structure consisting of 16 cores and a sheath surrounding them, and the tip has a branched portion made up of the 16 cores exposed from the sheath. The toothbrush according to claim 1, wherein the outer diameter of each core portion of the core-sheath structure is 15 to 22 μm.

4. When the entire bundle of bristles in the head section is pressed at a constant speed of 0.1 mm / min along the direction of the protrusion of the bristles, from the tip to the base, until the indentation depth is 1 mm, the maximum average pressure value is 400 g / cm². ２ The toothbrush according to claim 1, which is as follows:

5. P1 is defined as the maximum value of the average pressure when the entire bundle of hair in the head section is pressed at a constant speed of 0.1 mm / min along the direction of protrusion of the hair bundle, from the tip to the base, until the amount of indentation is 1 mm. When all the hairs in the multiple hair bundles implanted in the head portion are 16-branched hairs, and the same pressure is applied, the maximum value of the average pressure when the same pressure is applied is defined as P0. The value of P1 is 60 g / cm³ higher than the value of P0. ２ The toothbrush according to claim 1, which has the following increase.

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