WO2011048949A1

WO2011048949A1 - Toothbrush

Info

Publication number: WO2011048949A1
Application number: PCT/JP2010/067535
Authority: WO
Inventors: 靖奥田
Original assignee: ライオン株式会社
Priority date: 2009-10-21
Filing date: 2010-10-06
Publication date: 2011-04-28
Also published as: MY168505A; CN102573560A; KR101356263B1; CN102573560B; KR20120053533A

Abstract

A toothbrush configured so that a shock-absorbing section for preventing the bristles from bending is prevented from peeling away. A toothbrush (1) wherein a head section (2) in which the bristles are implanted is configured in such a manner that the surfaces between a bristle implanting surface (5) in which the bristles are implanted and side surfaces (6) which are adjacent to the bristle implanting surface (5) are rounded surfaces (7), that bristle implanting holes (4) are formed in the bristle implanting surface (5), and that the peripheral edges (42) of the bristle implanting holes (4) are formed as a shock-absorbing section (30) which consists of a resin having a lower hardness than the material of a base (20). The shock-absorbing section (30) is joined in the regions of the rounded surfaces (7) to the base (20). The joint surfaces (22) between the shock-absorbing surface (30) and the base (20) are sloped surfaces which slope to the outer sides of the head section (2) relative to the bristle implanting surface (5).

Description

toothbrush

The present invention relates to a toothbrush.
This application claims priority based on Japanese Patent Application Nos. 2009-242457 and 2009-242458 filed in Japan on October 21, 2009, the contents of which are incorporated herein by reference.

Filaments made of a polyester resin such as polytrimethylene terephthalate (PTT) are widely used as toothbrush brushes because they are cheaper than nylon and have excellent processability by chemical treatment. In addition, since the polyester-based resin is superior in elongation recovery compared to nylon, there is an advantage that the tip of the bristles is difficult to open when used as a toothbrush brush.

Normally, a toothbrush has a brush implanted on a base made of a relatively hard material such as polypropylene resin (PP) or polyethylene terephthalate resin (PET), but when a polyester resin filament is used for the brush, While durability against hair opening is good, there is a problem that the root is bent or cut (hair breakage).
This broken hair has a side surface due to the fact that the base portion of the brush repeatedly hits the peripheral edge portion of the flock hole at the time of brushing and the brush is broken. Moreover, since this peripheral part is comprised with the hard material when the base part of a brush repeatedly hits the peripheral part of a flocking hole, there exists a side surface resulting from the fracture | rupture of a brush being caused.
To solve such a problem, a toothbrush in which an elastomer resin having a specific hardness is coated on a base and the peripheral portion of the flock hole is made of an elastomer resin has been proposed (for example, Patent Document 1). In this toothbrush, the peripheral portion is formed of an elastomer resin having a hardness lower than that of the base, and thereby the breakage of the hair is suppressed by the dispersion or relaxation of the stress to the base of the brush at the time of brushing.
In addition, for example, a toothbrush in which the peripheral edge portion of the flocked hole is chamfered has been proposed (for example, Patent Document 2). In this toothbrush, the breakage of the hair is suppressed by relaxing the stress applied to the base of the brush at the time of brushing.

JP 2007-6937 A JP 2007-6938 A

By the way, a relatively hard material such as polypropylene resin (PP) or polyethylene terephthalate resin (PET) is used for the base of the toothbrush. When the peripheral part (buffer part) of the flock hole comprised with elastomer resin is provided like patent document 1, the adhesion state of a buffer part and a base is influenced by the adhesiveness of mutual resin. For this reason, although elastomer resin is selected according to the material of a base, there exists a possibility that a buffer part may peel, for example, when the boundary of a buffer part and a base contacts a tooth | gear at the time of cleaning.
To cope with this problem, it is possible to expand the area of the buffer part to increase the adhesive area between the buffer part and the base and improve the adhesive strength. However, the elastomer resin is expensive and not economical. . In addition, if there is a buffer portion on the side surface of the base or the like, the buffer portion may be lost due to contact with the teeth at the time of brushing.

On the other hand, in order to prevent hair breakage by the peripheral edge portion (buffer portion) of the flock hole made of an elastomer resin as in Patent Document 1, the buffer portion needs to have a sufficient thickness for obtaining the effect of preventing hair breakage. And On the other hand, if the buffer portion is made too thick for preventing hair breakage, the head portion itself becomes thick and the usability is lowered. If the base is made thin in order to maintain the usability, the flocked hole in the base becomes shallow and sufficient flocking strength cannot be obtained.
Moreover, when chamfering was given to the peripheral part of the flock hole like patent document 2, there existed problems, such as toothpaste remaining in the part which performed the chamfering.

Then, the 1st objective of this invention is providing the toothbrush which can prevent peeling of a buffer part, suppressing the usage-amount of the elastomer resin for preventing a broken hair.
The second object of the present invention is to provide a toothbrush capable of preventing the brush from breaking while maintaining usability and flocking strength.

According to a first aspect of the toothbrush of the present invention, the head portion on which the brush is implanted has a rounded surface between a planted surface on which the brush is implanted and a side surface adjacent thereto, and a plurality of planted surfaces are arranged on the planted surface. A toothbrush that is a buffer portion in which a pore is formed and a peripheral portion of the flocked hole is formed of a resin having a hardness lower than that of a base material, wherein the buffer portion is the base in the region of the rounded surface. Here, the bonding surface between the buffer portion and the base is an inclined surface inclined toward the outside of the head portion when the flocked surface is used as a reference. .
In the first aspect of the toothbrush of the present invention, the joint surface is preferably an inclined surface of 100 to 150 ° with respect to the flocked surface, and the joint surface includes the base and the buffer portion. It is more preferable that a convex portion is formed on one of them, and a concave portion fitted to the convex portion is formed on the other side, and the buffer portion has a thickness on the base of 0.1. The distance in the flocked surface direction between the side surface of the head portion and the outer peripheral edge of the buffer portion is preferably 0.1 to 0.9 mm.

According to a second aspect of the toothbrush of the present invention, the head portion where the brush is implanted has a plurality of flocked holes formed on the flocked surface, and the peripheral edge portion of the flocked hole is lower in hardness than the material of the base. A toothbrush that is a buffer portion formed of resin, and an inclined surface that gradually decreases in diameter toward the inner portion of the flocked hole is formed on a peripheral portion of the base on the opening portion side of the flocked hole. And the said buffer part is formed in the area | region containing on the said inclined surface, It is characterized by the above-mentioned.
In the second aspect of the toothbrush of the present invention, the inclined surface is preferably a C-plane, the C-plane is preferably C0.1 to 0.8 mm, and the buffer portion is the base The upper thickness is preferably 0.1 to 1.0 mm, and a bundle of bristles in which a plurality of brushes are bundled on the flocked surface is planted in half using a flat plate-like wire. Also good.

As one aspect of the present invention, since the buffer portion is joined to the base in the area of the rounded surface, the boundary portion is less likely to come into contact with teeth or the like during the brushing, and peeling is unlikely to occur. In addition, since the joint surface between the buffer portion and the base is inclined with respect to the flocked surface, it is possible to prevent the occurrence of burrs near the boundary portion during molding. For this reason, peeling of the buffer part resulting from a burr | flash can be prevented, suppressing the usage-amount of the elastomer resin which comprises a buffer part.
As another aspect of the present invention, since the joint surface is 100 to 150 ° with respect to the flocked surface, it is possible to prevent the occurrence of burrs during molding.
As another aspect of the present invention, since the convex portion is formed on one of the base and the buffer portion, and the concave portion that fits the convex portion is formed on the other side, the buffer portion and the base Further improvement in adhesion can be achieved.
As another aspect of the present invention, since the thickness of the buffer portion is 0.1 to 1.0 mm, the adhesiveness between the buffer portion and the base can be further improved without impairing the usability of the toothbrush.
As another aspect of the present invention, since the distance from the side surface of the head portion to the outer peripheral edge of the buffer portion is 0.1 to 0.9 mm, the buffer portion and the buffer portion can be used without impairing the usability and flocking strength of the toothbrush. The adhesiveness with the base can be further improved.

As another aspect of the present invention, the peripheral portion of the flocked hole is a buffer portion formed from a resin whose hardness is lower than the material of the base, and the peripheral portion on the opening side of the flocked hole in the base is Since the inclined surface whose diameter gradually decreases as it goes toward the inner part of the flocked hole is formed, stress concentrated on the base of the brush can be relieved, and breakage can be prevented. In addition, the strength of the base is ensured, and usability and sufficient flocking strength can be maintained.
As another aspect of the present invention, since the inclined surface is a C-plane, the stress at the base of the brush can be relaxed, and breakage can be prevented.
As another aspect of the present invention, since the C-plane is C0.1 to 0.8 mm, it is possible to further improve the effect of preventing breakage and the flocking strength.
As another aspect of the present invention, since the buffer portion has a thickness of 0.1 to 1.0 mm on the base, it is possible to further improve the effect of preventing breakage.
As another aspect of the present invention, even if a hair bundle in which a plurality of brushes are bundled is planted using a flat wire on the hair transplantation surface, the hair transplantation strength can be ensured.

It is a top view of a toothbrush concerning one embodiment of the present invention. It is sectional drawing of the toothbrush concerning one Embodiment of this invention. It is sectional drawing of the toothbrush concerning one Embodiment of this invention. It is sectional drawing of the toothbrush concerning one Embodiment of this invention. It is a top view of a toothbrush concerning one embodiment of the present invention. It is sectional drawing of the toothbrush concerning one Embodiment of this invention. It is a fragmentary sectional view of the toothbrush explaining the flock hole in the state where the brush was implanted.

The first aspect of the toothbrush of the present invention will be described below with reference to the drawings. FIG. 1 is a view for explaining a toothbrush 1 of the present invention, and is a plan view showing a head portion provided at the tip of a handle portion (not shown) of the toothbrush 1, and FIG. FIG. For convenience of explanation, illustration of the brush is omitted, and only the flocked hole into which the brush is implanted is illustrated.

As shown in FIGS. 1 and 2, the toothbrush 1 includes a head portion 2 having a rounded surface 7 between a flocked surface 5 for planting a brush and a side surface 6 adjacent to the flocked surface 5. The radius of curvature R is about 0.5 to 0.7 mm.
The head portion 2 includes a base 20 on which a plurality of bottomed cylindrical flock holes 4 are formed, and a buffer portion 30 that covers the surface 21 of the base 20 on which the flock holes 4 are formed. Thereby, the hole peripheral part 42 of the flocking hole 4 is comprised by the buffer part 30. FIG. The flocking hole 4 has a depth D from the flocking surface 5 of about 3.0 to 5.0 mm and a hole diameter d of about 1.5 to 3.0 mm.

The buffer portion 30 is joined to the base 20 at the boundary portion 32 in the region of the rounded surface 7, and the joint surface 22 between the base 20 and the buffer portion 30 is directed outward from the head portion 2 with respect to the flocked surface 5. It is an inclined surface inclined toward. Thereby, the buffer part 30 is provided so that the boundary part 32 may be located inside the outline of the head part 2 in plan view. The inclination angle of the bonding surface 22 is not particularly limited, but the angle θ formed by the inclined surface P of the bonding surface 22 and the virtual surface Q parallel to the flocked surface 5 is preferably 100 to 150 °, more preferably 115 to 135 °.

The material of the base 20 can be determined in consideration of the rigidity and mechanical characteristics required for the toothbrush 1. For example, by using a high-hardness resin having a flexural modulus (JIS K7203) in the range of 500 to 3000 MPa, the toothbrush 1 The required mechanical properties can be obtained. Examples of such high-hardness resins include PP, PET, polystyrene resin (PS), acrylonitrile butadiene styrene resin (ABS), cellulose propionate resin (CP), polyarylate resin, polycarbonate resin, acrylonitrile styrene resin (AS Etc.), and one or more of these can be used.

When projected, the edge distance l between the contour of the head portion 2 formed by the outermost peripheral portion of the base 20 and the boundary portion 32, that is, the distance in the flocked surface direction from the side surface 6 to the outer peripheral edge of the buffer portion 30 is The thickness is preferably 0.1 to 0.9 mm, more preferably 0.2 to 0.5 mm. If it is less than 0.1 mm, there will be a hindrance to the molding of the base 20, and if it exceeds 0.9 mm, the head part 2 becomes large and the operability of the toothbrush 1 becomes poor.

The buffer portion 30 is formed of a resin (low hardness resin) whose hardness measured by “JIS K6253, hardness test, test condition JIS A” is lower than the base 20, and for example, the hardness measured by JIS K6253 , Preferably 5 to 100, more preferably 15 to 90.

Examples of the low hardness resin include polyolefin-based thermoplastic elastomers, polystyrene-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, polyester-based thermoplastic elastomers, 1,2-polybutadiene-based thermoplastic elastomers, and ethylene-vinyl acetate-based heat. Examples thereof include thermoplastic elastomers (TPEE) such as plastic elastomers, polyvinyl chloride thermoplastic elastomers, natural rubber thermoplastic elastomers, fluorine thermoplastic elastomers, and trans-polyisoprene thermoplastic elastomers.

The thickness t on the surface 21 of the base 20 of the buffer part 30 can be determined in consideration of the depth D of the flocking hole 4, the hole diameter d, the material of the brush, and the like, for example, 0.1 to 1.0 mm. Preferably, it is 0.2 to 0.8 mm, more preferably 0.3 to 0.7 mm. If it is 0.1 mm or more, the adhesiveness between the buffer portion 30 and the base 20 can be improved, and the stress on the base portion of the brush at the time of brushing can be relieved to prevent the breakage of the hair. If so, the flocking strength of the brush planted in the flocking hole 4 can be maintained.

The material of the brush is not particularly limited, and a known material used for a toothbrush can be used. Examples of the material of the brush include, for example, polyester alone or polyester resin containing polyester as a main component, nylon simple substance or nylon resin containing nylon as a main component, polyolefin simple substance such as polypropylene and polyethylene, or olefin type containing polyolefin as a main component. Examples of the resin include polyester resins. This is because the polyester-based resin is more likely to be broken at the base as compared with other materials, and thus the effect of providing the buffer portion 30 appears remarkably. Examples of the polyester resin include PET, polybutylene terephthalate (PBT), and polytrimethylene terephthalate (PTT). Among them, PTT is more preferable. Since PTT easily breaks even among polyester resins, the effect of providing the buffer portion 30 appears remarkably.

The thickness of the brush is not particularly limited, but is, for example, in the range of 6 to 11 mil (that is, 0.152 to 0.279 mm; where 1 mil = 1/1000 inch). Moreover, although the cross-sectional shape of a brush is mainly circular, it is not specifically limited to such a shape. For example, it may be a brush having a cross-sectional shape such as a triangle, a quadrangle, a hexagon, or a petal shape, or a combination thereof. Moreover, the shape of the entire brush previously processed, for example, into a wave shape, a twist shape, a jagged shape, or the like may be used, or a combination of these may be used.

Further, as the brush, those having substantially the same outer diameter except for the rounded portion of the hair tip may be used, or a taper having a gradually decreasing outer diameter toward the hair tip may be used. Furthermore, the tip shape of the brush may be, for example, a spatula shape, a tapered wide shape, or a spherical shape.

The brush is usually planted in the flock hole 4 with a bundle of plural hairs as a unit, but the lengths of the brushes may be uniform or irregular. Further, the hair tip contour shape (hair cutting shape) of the hair bundle may be a dome shape, a mountain valley shape, or an uneven step shape, in addition to the flat shape.

Next, the manufacturing method of the toothbrush 1 of this invention is demonstrated. In this manufacturing method, a base 20 is molded (primary molding), a buffer unit 30 is provided on the obtained base 20 (secondary molding), and a brush handle including a head unit 2 and a handle unit (not shown) is provided. A forming step to obtain, and a flocking step to plant a brush on the head portion 2 of the brush handle.

The primary molding uses a pair of primary molds that form a cavity corresponding to the base 20, and the base 20 is molded by injecting a resin (also referred to as a primary resin) that constitutes the base 20 into the cavity. It is an operation to do.

The subsequent secondary molding uses a pair of secondary molds in which cavities corresponding to the brush handles are formed, and the base 20 obtained by the primary molding is loaded into the cavity of the secondary mold, and the secondary mold This is an operation of injecting a resin (sometimes referred to as a secondary resin) constituting the buffer portion 30 and providing the buffer portion 30 on the base 20. The cavity of the secondary mold is such that when the base 20 is loaded in the cavity, the space formed between the loaded base 20 and the cavity has a shape corresponding to the buffer portion 30. is there.

The secondary mold includes a first split mold on the side on which the flocked surface 5 is formed and a second split mold for fixing the bottom surface 8 side of the head portion 2. The first split mold and the second split mold are: The one-dot chain line O is fitted as PL (Parting Line). In addition, PL is located substantially in the middle between the flocked surface 5 and the bottom surface 8 and is substantially parallel to the flocked surface 5.

The flocking process is a process in which a brush is implanted in the head part 2 of the brush handle obtained by the secondary molding to obtain the toothbrush 1. A known flocking method can be used for planting the brush. For example, a bunch of hair consisting of a plurality of brushes is folded in half, and a retaining member (flat wire) is sandwiched therebetween, and this flat wire is inserted into the flocking hole 4. A flat wire flocking method in which the hair bundle is fixed by driving into the hair. A conventionally well-known thing can be used for this flat wire, For example, the flat thing made from brass or aluminum is mentioned.

The dimension and shape of the flat wire can be determined in consideration of the diameter of the flock hole 4 and the like. Further, the length of the flat wire driven into the flocking hole 4 is not particularly limited, and is preferably a length that can hold the hair bundle and does not cause cracking or whitening of the brush handle during flocking. It is preferable that the length of the long axis of the pore 4 in the flat wire driving direction is 0.3 to 0.5 mm longer. The flat wire driving angle can be freely selected, but it is preferably in the range of 5 to 80 ° with respect to the longitudinal direction of the brush handle, and more preferably 15 to 30 ° in order to avoid the occurrence of cracking and whitening. is there. Further, the flat wire driving angle need not be the same for all the flocking holes 4, and may be different for each flocking hole 4.

As described above, as one aspect of the present invention, since the hole peripheral portion 42 of the flocked hole 4 is configured by the buffer portion 30, the stress on the base portion of the brush at the time of brushing is relieved, and the occurrence of breakage occurs. Can be suppressed. In addition, the degree of freedom of movement of the brush is increased at the time of brushing, and the brush is likely to enter a gap such as between teeth, thereby improving the cleaning power. Furthermore, since the brush moves flexibly as the degree of freedom of movement of the brush increases, the operability of the toothbrush 1 can be improved by shortening the brush length.

As another aspect of the present invention, since the boundary portion 32 between the base 20 and the buffer portion 30 is located in the region of the rounded surface 7, the boundary portion 32 is less likely to come into contact with teeth or the like at the time of brushing, The buffer part 30 can be prevented from being peeled off or missing.

As another aspect of the present invention, since the joint surface 22 between the base 20 and the buffer portion 30 is an inclined surface toward the outside of the head portion 2, burrs are prevented from being generated at the boundary portion 32 when the brush handle is formed. In addition, it is possible to prevent the base 20 and the buffer portion 30 from peeling off due to burrs.
In secondary molding, if the inclination angle θ of the joint surface 22 is 90 ° as in the prior art (Patent Document 1, etc.), the base 20 is pressed by the first split mold, and the joint surface 22 is in the direction of the flock hole 4. Lean on. When the joint surface 22 is inclined in the direction of the flock hole 4, a gap is generated between the first split mold and the round surface 7. When the secondary resin is injected in this state, the secondary resin flows into the gap between the rounded surface 7 and the first split mold, and tends to be burrs.
The toothbrush 1 which is one aspect of the present invention is an inclined surface in which the joint surface 22 faces the outside of the head portion 2, so that even if the base 20 is pressed by the first split mold, the joint surface 22 is easily planted. It is possible to prevent a gap from being formed between the rounded surface 7 and the first split mold without inclining toward the pore 4 side. As a result, burrs are hardly generated in the vicinity of the boundary portion 32, and peeling / missing of the buffer portion 30 due to the burrs at the time of printing is prevented. In addition, since a space (flow path) filled with the secondary resin is secured, insufficient filling (short shot) of the secondary resin can be prevented.

The present invention is not limited to the embodiment described above.
For example, a convex portion may be formed on one of the base and the buffer portion, and a concave portion fitted to the convex portion may be formed on the other side of the joint surface.
For example, as in the head portion 102 shown in FIG. 3, the joint surface 122 between the base 120 and the buffer portion 130 has a convex portion 124 formed on the base 120 and a concave portion 132 formed on the buffer portion 130. It may be fitted.
For example, as in the head portion 202 shown in FIG. 4, the joint surface 222 between the base 220 and the buffer portion 230 has a concave portion 224 formed in the base 220 and a convex portion 232 formed in the buffer portion 230. And may be fitted.
The

protrusions

124 and 232 may have, for example, a plurality of protrusions such as a cone shape, a pyramid shape, a cylinder shape, and a prism shape, or a rib formed in a band shape along the joint surface. It may be.

In the above-described embodiment, the flocked hole has a bottomed cylindrical shape, but the shape of the flocked hole is not particularly limited, and for example, the cross section may be an ellipse or a polygon.

In the above-described embodiment, the hair bundle is planted by the flat wire flocking method, but the hair transplantation method is not limited to this. For example, heat that press-fits and fixes the lower end of the hair bundle into the molten resin that becomes the hair transplantation portion. A fusion method, an in-mold method in which a molten resin is injected into a mold and a flocked part is formed after the lower end of the hair bundle is heated to form a molten lump may be used.

Subsequently, a second aspect of the toothbrush of the present invention will be described below with reference to the drawings. FIG. 5 is a view for explaining the toothbrush 301 of the present invention, and is a plan view showing a head portion provided at the tip of a handle portion (not shown) of the toothbrush 301. FIG. 6 is a sectional view of FIG. FIG. For convenience of explanation, illustration of the brush is omitted, and only the flocked hole into which the brush is implanted is illustrated.

As shown in FIGS. 5 and 6, in the toothbrush 301, a plurality of flocked holes 304 are formed on the flocked surface 305, and a hole peripheral portion 342 of the flocked hole 304 is configured by a buffer portion 330 provided on the base 320. The head portion 302 is provided. The head portion 302 has a rounded surface 307 between the flocked surface 305 and a side surface 306 adjacent to the flocked surface 305 and facing the bottom surface 308. The radius of curvature R of the rounded surface 307 is about 0.5 to 0.7 mm. The size of the head portion 302 is not particularly limited, but the width W is about 7.0 to 12.0 mm, and the thickness T is about 3.0 to 6.0 mm.

A plurality of bottomed cylindrical flocking holes 304 are formed on the flocking surface 305 side of the head portion 302, and the flocking hole 304 has a depth D1 from the flocking surface 305 of about 2.0 to 5.0 mm. The diameter d is about 1.0 to 3.0 mm. Further, the depth D2 of the flock hole 304 in the base 320 is, for example, about 1.5 to 4.5 mm. This is because if the depth D2 is within the above range, a retainer (flat wire) described later can be firmly fixed.
As shown in FIG. 7, a hair bundle 312 composed of a plurality of brushes 310 is fixed in a flock hole 304 by a flat wire 314 that is folded in two and sandwiched therebetween. Here, reference numeral 313 denotes a base portion that is a portion inserted into the flock hole 304 in the hair bundle 312.

In the base hole peripheral portion 321, which is the peripheral portion of the flocked hole 304 in the base 320, an inclined surface 322 whose diameter gradually decreases toward the back of the flocked hole 304, that is, toward the hole bottom 344 is formed. In this embodiment, the inclined surface 322 is a C plane, and this C plane is preferably C0.1 to 0.8 mm, more preferably C0.1 to 0.5 mm, and further preferably C0.2 to 0.4 mm. It is. If C is less than 0.1 mm, the effect of preventing hair breakage may be insufficient, and if it exceeds 0.8 mm, the gap between adjacent flocking holes 304 is widened and the head portion 302 is enlarged, thereby improving usability. May decrease.
In this specification, the C plane means a plane that appears by chamfering corners of two orthogonal planes at an angle of 45 ° from each plane, and a numerical value is displayed continuously to the C. In this case, it indicates that chamfering is performed at an angle of 45 ° at the position of the numerical length (usually expressed in mm) from the intersecting line of the two orthogonal surfaces. For example, when C 0.5 mm is displayed, it indicates that the corner is chamfered at an angle of 45 ° at a position 0.5 mm from the corner (intersection line) of two orthogonal surfaces.
Further, a boundary portion 332 that is an outer peripheral edge of the buffer portion 330 is a region of the rounded surface 307. Thereby, the boundary part 332 is set to the inner side in the direction of the flocked surface 305 than the contour of the head part 302 formed by the outermost peripheral part of the base 320.

The material of the base 320 can be determined in consideration of the rigidity and mechanical characteristics required for the toothbrush 301, and specifically, a high-hardness resin similar to the high-hardness resin exemplified as the material of the base 20 can be given. .

The buffer portion 330 is formed in a region including on the inclined surface 322 and constitutes a hole peripheral portion 342 that is a peripheral portion of the flocking hole 304, and the inner peripheral surface 334 of the buffer portion 330 is planted on the base 320. The inner surface 324 of the pore 304 is substantially flush.
The thickness t of the buffer portion 330 on the base 320 can be determined in consideration of the depth D of the flocking hole 304, the hole diameter d, the material of the brush 310, and the like, for example, 0.1 to 1.0 mm is preferable. 0.3 to 0.8 mm is more preferable, 0.4 to 0.7 mm is more preferable, and 0.5 to 0.6 mm is particularly preferable. If the thickness is 0.1 mm or more, the adhesiveness between the buffer portion 330 and the base 320 can be improved, and the stress on the base portion 313 at the time of brushing can be relieved to prevent hair breakage. For example, while ensuring the usability of the toothbrush 301, the flocking strength of the brush 310 planted in the flocking hole 304 can be maintained. In addition, if it is within the above range, insufficient filling (short shot) of the resin constituting the buffer portion 330 at the time of molding can be prevented.

About the material and the hardness of the buffer part 330, it is the same as that of the said buffer part 30, and the example of the low hardness resin used for the buffer part 330 is the same as the example of the low hardness resin used for the said buffer part 30. .

The material, thickness, shape, length, and mode of the hair bundle of the brush 310 are the same as those of the brush of the toothbrush 1, and specific examples thereof are also the same.

The material, dimensions, and shape of the flat wire 314 are the same as those of the flat wire 14, and the specific examples thereof are also the same. Moreover, as a preferable example of the driving angle of the flat wire 314, the same example as the preferable driving angle of the flat wire 14 can be given.

Next, a method for manufacturing the toothbrush 301 of the present invention will be described. In this manufacturing method, a base 320 is molded (primary molding), a buffer portion 330 is provided on the obtained base 320 (secondary molding), and a brush handle including a head portion 302 and a handle portion (not shown) is provided. A forming step to obtain, and a flocking step of planting the brush 310 on the head portion 302 of the brush handle.

The primary molding uses a pair of primary molds that form a cavity corresponding to the base 320, and the base 320 is molded by injecting a resin (also referred to as a primary resin) constituting the base 320 into the cavity. It is an operation to do.

The subsequent secondary molding uses a pair of secondary molds in which cavities corresponding to the brush handles are formed, and the base 320 obtained by the primary molding is loaded into the cavity of the secondary mold, and the secondary mold This is an operation of injecting a resin (sometimes referred to as a secondary resin) constituting the buffer part 330 to provide the buffer part 330 on the base 320. The cavity of the secondary mold is such that when the base 320 is loaded in the cavity, the space formed between the loaded base 320 and the cavity has a shape corresponding to the buffer portion 330. .

The flocking process is a process in which the brush 310 is implanted in the head portion 302 of the brush handle obtained by the secondary molding to obtain the toothbrush 301. The brush 310 can be planted by using a known flocking device, for example, a flat wire type flocking device.

According to the present invention, since the hole peripheral portion 342 is configured by the buffer portion 330, the buffer portion 330 can relieve the stress generated in the base portion 313 during the cleaning. As a result, it is possible to prevent the brush 310 from being broken. Furthermore, since the inclined surface 322 is the C surface, the thickness t of the buffering portion 330 is set to a thickness sufficient to prevent hair breakage without increasing the depth D1 of the flocking hole 304, and the flocking hole in the base 320 is also provided. The depth D2 of 304 can be set to a depth at which sufficient flocking strength can be obtained. As a result, it is possible to prevent the brush 310 from being broken while maintaining the usability of the toothbrush 301 and the flocking strength.
In addition, by making the inclined surface 322 a C-plane, the base 320 and the buffer portion 330 have a large joint area, so that the adhesive force between the base 320 and the buffer portion 330 can be improved, and the base 313 is reached. The stress relaxation can be improved.

The present invention is not limited to the embodiment described above.
In the above-described embodiment, the inclined surface of the peripheral edge of the base hole is a C surface, but this inclined surface may be any one that gradually decreases in diameter toward the inner part of the flocked hole. For example, it can be determined in the range of 20 to 70 °, preferably 30 to 60 ° with respect to the plane. For example, the inclined surface may be a rounded surface. However, from the viewpoint of improving the effect of preventing hair breakage, the inclined surface is preferably a C surface, that is, a surface chamfered at an inclination angle of 45 ° with respect to the flocked surface.

In the above-described embodiment, the hair bundle is planted by flat wire flocking. For example, the heat fusion method in which the lower end of the hair bundle is press-fitted into the molten resin serving as the flocked portion, and the lower end of the hair bundle is fixed. After forming a molten lump by heating, a molten resin may be injected into the mold to be planted by an in-mold method or the like in which a flocked portion is formed.

(Examples 1A to 5A)
A toothbrush similar to the toothbrush 1 shown in FIG. 1 was produced according to the specifications in Table 1A. PP was used as the primary resin constituting the base, and styrene elastomer resin (hardness 60) was used as the secondary resin constituting the buffer portion. A PTT (φ0.2 mm) brush was made into 20 hair bundles, and the hair bundle was folded in half using a flocking machine (manufactured by ZAHORANSKY), and was driven into 23 flock holes with a flat wire (250shot) / Min).
About each produced toothbrush, short shot, burr | flash generation | occurrence | production, peeling difficulty, and flocking strength were evaluated, and the result is shown in Table 1A.

(Comparative Example 1A)
A toothbrush was produced in the same manner as in Example 1A, except that the angle of the joint surface was 180 °, that is, parallel to the flocked surface, and the boundary portion was positioned in the side region. About the produced toothbrush, short shot, burr | flash generation | occurrence | production, peeling difficulty, and flocking strength were evaluated, and the result is shown in Table 1A.

(Comparative Example 2A)
A toothbrush was produced in the same manner as in Example 1A, except that the angle of the joint surface was 90 ° and the boundary portion was located in the region of the flocked surface. About the produced toothbrush, short shot, burr | flash generation | occurrence | production, peeling difficulty, and flocking strength were evaluated, and the result is shown in Table 1A.

[Table 1A]

(Short shot evaluation)
The short shot was evaluated by visually checking the toothbrush of each example and classifying the results according to the following evaluation criteria.
<Evaluation criteria>
b: No chipping or deformation is observed in the shape of the buffer portion.
c: Although a large deformation was not recognized in the shape of the buffer part, a chip was partially observed.
d: A large deformation was recognized in the shape of the buffer portion.

(Burr generation)
The evaluation of the occurrence of burrs was performed by visually checking the occurrence of the burrs in each example and classifying them according to the following evaluation criteria.
<Evaluation criteria>
a: Generation | occurrence | production of the burr | flash was not recognized at all.
b: Generation of burrs was observed in an area of less than 20% of the boundary.
c: Generation of burrs was observed in the region of 20% or more and less than 30% of the boundary portion.
d: Burr generation was observed in a region of 30% or more of the boundary portion.

(Peeling difficulty)
The difficulty of peeling was evaluated by using the toothbrushes of each example by five monitors and classifying the average number of times of use when the peeling of the boundary portion was confirmed according to the following evaluation criteria.
<Evaluation criteria>
a: Peeling could not be confirmed after 200 times of use.
b: Peeling was confirmed when the number of use was 100 times or more and less than 200 times.
c: Peeling was confirmed when the number of use was 50 times or more and less than 100 times.
d: Peeling was confirmed when the number of uses was less than 50.

(Flocking strength)
The flocking strength was measured by measuring the maximum tensile stress (N) until the bunch was removed from the flocked hole using an autograph (manufactured by Shimadzu Corporation) by holding the bunch in one flocked hole with a dedicated instrument. Speed 20 mm / min, n = 20). The measured values were classified into the following evaluation criteria to evaluate the flocking strength. In the table, the measurement values are shown in parentheses together with the evaluation results.
<Evaluation criteria>
a: 25N or more b: 20N or more and less than 25N c: 15N or more and less than 20N d: less than 15N

(Comprehensive evaluation)
The results of short shots, burrs, difficulty of peeling, and flocking strength were classified according to the following evaluation criteria to make a comprehensive evaluation.
<Evaluation criteria>
a: Evaluation of short shot is “b”, evaluation of burr generation, difficulty of peeling, and flocking strength is “b” or “a”.
b: Evaluation of short shot is “b”, evaluation of burr generation, difficulty of peeling and flocking strength is “c” to “a”, and there is one or more “c”, or evaluation of short shot Is “c”, and evaluation of burr generation, difficulty of peeling and flocking strength is “b” to “a”.
c: Evaluation of short shot is “c”, evaluation of burr generation, difficulty of peeling and flocking strength is “c” to “a” and there is one or more “c”, or short shot, burr There is one “d” in the evaluation of generation, exfoliation difficulty and flocking strength.
d: There are two or more “d” in the evaluation of short shot, occurrence of burrs, difficulty of peeling, and flocking strength.

As shown in Table 1A, in Examples 1A to 5A to which the present invention is applied, the evaluation of the occurrence of burrs is good as “b” or “a”, and the evaluation of the difficulty of peeling is good as “b” or “a”. Met. In addition, in Examples 1A to 5A, the overall evaluation is “b” or “a”, and the production suitability evaluated by the difficulty of short shot, burr generation and peeling, and the functionality evaluated by the flocking strength. Both were excellent.
On the other hand, in Comparative Example 1A in which the angle of the joint surface was 180 °, the evaluation of the difficulty of peeling was “d”. In Comparative Example 2 in which the angle of the joint surface was 90 °, the short shot evaluation was “d”.
From this, it was found that by causing the joint surface to be inclined with respect to the flocked surface, it is possible to prevent the occurrence of short shots and burrs while maintaining the difficulty of peeling and the flocked strength. Moreover, since the toothbrush to which the present invention is applied can prevent the generation of burrs, it has been found that the peeling of the buffer portion can be suppressed.

(Examples 1B to 8B)
In accordance with the specifications in Table 1B, a toothbrush (inclined surface 322: C surface) similar to the toothbrush 301 shown in FIG. 5 was produced. PP was used as the primary resin constituting the base, and styrene elastomer resin (hardness 60) was used as the secondary resin constituting the buffer portion. A PTT (φ0.2 mm) brush was made into 20 hair bundles, and the hair bundle was folded in half using a flocking machine (manufactured by ZAHORANSKY), and was driven into 23 flock holes with a flat wire (250shot) / Min).
About each produced toothbrush, durability, flocking strength, head part strength, and usability were evaluated, and the result is shown in Table 1B.

(Comparative Example 1B)
A toothbrush was produced in the same manner as in Example 1B except that the surface corresponding to the inclined surface 322 shown in FIG. 5 was a surface substantially parallel to the flocked surface.
About the produced toothbrush, durability, flocking strength, head part strength, and usability were evaluated, and the result is shown in Table 1B.

[Table 1B]

(Durability evaluation)
With respect to a brush plate (made of stainless steel) assuming a molar dentition, reciprocal brushing was performed at a load of 400 g, a stroke of 40 mm, and 240 rpm, and the number of times of brushing when a toothbrush occurred in each example was examined. The number of times of brushing was classified into the following evaluation criteria to evaluate durability. In the reciprocating brushing, a 50% by mass aqueous solution of a commercial dentifrice was used as the cleaning liquid.

<Evaluation criteria>
a: No broken hair after 150,000 times b: Broken hair after 100,000 times and less than 150,000 times c: Broken hair after 50,000 times and less than 100,000 times d: Broken hair after less than 50,000 times

(Flocking strength)
A hair bundle in one flock hole was grasped with a dedicated instrument, and the maximum tensile stress (N) until the bunch was removed from the flock hole was measured using an autograph (manufactured by Shimadzu Corporation) (tensile speed 20 mm / min. , N = 20). The measured values were classified into the following evaluation criteria to evaluate the flocking strength. In the table, the measurement values are shown in parentheses together with the evaluation results.

<Evaluation criteria>
a: 25N or more b: 20N or more and less than 25N c: 15N or more and less than 20N d: less than 15N

(Head strength)
The brush which protruded from the flock hole of the toothbrush of each example was cut | disconnected, and the sample which smoothed the flocked surface side of the head part was prepared. This sample was fixed to a digital impact tester (DG-1 type, manufactured by Toyo Seiki Seisakusho Co., Ltd.), weighed with 0.5 J from the flocked surface side, and measured the absorbed energy (J) when the head part broke ( n = 10). The measured values were classified into the following evaluation criteria, and the head portion strength was evaluated. In the table, the measurement values are shown in parentheses together with the evaluation results.

<Evaluation criteria>
a: 0.3 J or more b: 0.2 J or more and less than 0.3 J c: 0.1 J or more and less than 0.2 J d: less than 0.1 J

(Evaluation of usability)
Usability was evaluated by 10 subjects who cleaned their mouth and sensuality of the subjects. Specifically, regarding operability in the oral cavity, 3 points are given when “there is no problem with operability”, 2 points when “the head part feels slightly larger, but there is no problem with operability”, In the case of “poor operability”, it was evaluated as one point. The average score obtained by this sensory evaluation was classified into the following evaluation criteria, and usability was evaluated. In the table, the average score is shown in parentheses together with the evaluation result.

<Evaluation criteria>
a: 2.5 points or more b: 2.0 points or more and less than 2.5 points c: 1.5 points or more and less than 2.0 points d: Less than 1.5 points

(Comprehensive evaluation)
Based on the evaluation results of endurance test, flocking strength, head portion strength and usability (generally referred to as evaluation items), it was classified into the following evaluation criteria to be comprehensive evaluation.

<Evaluation criteria>
a: Each evaluation of durability test, flocking strength, and head portion strength is “b” or “a”, and “a” is two or more, and usability evaluation is “b” or “a”.
b: Each evaluation of durability test, flocking strength, and head portion strength is “b” or “a”, and “a” is 2 or more, usability evaluation is “c”, or durability test, flocking strength In addition, each evaluation of the head portion strength is “b” or “a”, and “a” is one or less, and the usability evaluation is “c” to “a”.
c: Each evaluation of durability test, flocking strength, and head portion strength is “c” to “a”, and “c” is one or more, and usability evaluation is “c” to “a”.
d: Any of the evaluation items is “d”.

As shown in Table 1B, Examples 1B to 8B to which the present invention was applied had good durability, flocking strength, and head portion strength.
On the other hand, Comparative Example 1B in which the peripheral edge of the base hole is not inclined is inferior in terms of durability.

According to the present invention, it is possible to provide a toothbrush that can prevent peeling of the buffer portion while suppressing the amount of elastomer resin used for preventing breakage. Further, it is possible to provide a toothbrush that can prevent the brush from breaking while maintaining usability and flocking strength.

DESCRIPTION OF SYMBOLS 1 Toothbrush 2,102,202 Head part 4 Flocking hole 5 Flocked surface 6 Side 7 Round surface 20,120,220 Base 22,122,222 Joining surface 30,130,230 Buffer part 32 Boundary part 42 Hole

peripheral part

124, 232

Convex part

132, 224 Concave part 301 Toothbrush 302 Head part 304 Flocking hole 305 Flocking surface 320 Base 321 Base hole peripheral part 322 Inclined surface 330 Buffer part 342 Hole peripheral part

Claims

The head portion where the brush is implanted has a rounded surface between the flocked surface on which the brush is implanted and the side surface adjacent thereto, and a plurality of flocked holes are formed on the flocked surface, and the flocked hole A toothbrush that is a buffer portion formed of a resin whose hardness is lower than the material of the base,
The buffer portion is joined to the base in the region of the rounded surface;
Here, the toothbrush characterized in that the joint surface between the buffer portion and the base is an inclined surface inclined toward the outside of the head portion when the flocked surface is used as a reference.
The toothbrush according to claim 1, wherein the joint surface is an inclined surface of 100 to 150 ° with respect to the flocked surface.
In the joint surface, a convex portion is formed on one of the base and the buffer portion, and a concave portion that fits the convex portion is formed on the other side. The toothbrush according to claim 1 or 2.
The toothbrush according to any one of claims 1 to 3, wherein the buffer portion has a thickness on the base of 0.1 to 1.0 mm.
The distance in the flocked surface direction between the side surface of the head portion and the outer peripheral edge of the buffer portion is 0.1 to 0.9 mm, according to any one of claims 1 to 4. Toothbrush.
A toothbrush in which the head portion where the brush is implanted has a buffer portion in which a plurality of flocked holes are formed on the flocked surface, and the peripheral portion of the flocked hole is formed of a resin having a lower hardness than the material of the base Because
An inclined surface whose diameter gradually decreases as it goes in the direction toward the back of the flocked hole is formed at the peripheral portion of the base on the opening side of the flocked hole, and the buffer portion is formed in a region including on the inclined surface Said toothbrush characterized by the above-mentioned.
The toothbrush according to claim 6, wherein the inclined surface is a C surface.
The toothbrush according to claim 7, wherein the C surface is C0.1 to 0.8 mm.
The toothbrush according to any one of claims 6 to 8, wherein the buffer portion has a thickness on the base of 0.1 to 1.0 mm.
10. A hair bundle obtained by bundling a plurality of brushes on the flocked surface is planted in half using a flat flat wire. Toothbrush.