JP2011087702A - Toothbrush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothbrush whose cushioning parts are prevented from separating while reducing use of elastomer resin for preventing bending of bristles. <P>SOLUTION: In the toothbrush, the bristles-implanted head part 2 of which has rounded surfaces 7 between the bristles-implanted bristle implanting surface 5 and the side surfaces 6 adjacent to them, keeps a plurality of bristle implanting holes 4 formed in the bristle implanting surface 5, and makes peripheral parts 42 of the bristle implanting holes 4 serve as cushioning parts 30 formed of a resin exhibiting a lower hardness than the material of a base 20, the cushioning parts 30 are bonded to the base 20 in the area of the rounded surfaces 7, and each of joint surfaces 22 between the cushioning parts 30 and the base 20 is an inclined surface which is inclined outward from the head part 2 with reference to the bristle implanting surface 5. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a toothbrush.

  Filaments made of polyester resins such as polytrimethylene terephthalate (PTT) are widely used as toothbrush brushes because they are less expensive 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.

A filament made of a polyester-based resin has a problem that it has a good durability against hair opening, but is bent or cut at the base (hair breakage). This broken hair is caused by the brush base repeatedly hitting the peripheral edge of the flocked hole at the time of brushing and causing the brush to break.
To solve such a problem, a toothbrush in which the peripheral portion of the flock hole is formed of an elastomer resin having a specific hardness has been proposed (for example, Patent Document 1). In this toothbrush, the breakage of the hair is suppressed by the dispersion of stress to the base of the brush at the time of brushing.

JP 2007-6937 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.

  Then, this invention aims at the toothbrush which can prevent peeling of a buffer part, suppressing the usage-amount of the elastomer resin for preventing a broken hair.

In the toothbrush of the present invention, the head portion where the brush is implanted has a rounded surface between the flocked surface where the brush is implanted and the side surface adjacent thereto, and a plurality of flocked holes are formed in the flocked surface. In addition, in the toothbrush in which the peripheral portion of the flocked hole is a buffer portion made 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, and the buffer portion and the base The joining surface with the base is an inclined surface that is inclined toward the outside of the head portion with respect to the flocked surface.
The joint surface is preferably an inclined surface of 100 to 150 ° with respect to the flocked surface, and a convex portion is formed on one of the base and the buffer portion on the joint surface. It is more preferable that a concave portion fitted to the convex portion is formed on the other side, and the buffer portion preferably has a thickness on the base of 0.1 to 1.0 mm, and the head The distance in the flocked surface direction between the side surface of the portion and the outer peripheral edge of the buffer portion is preferably 0.1 to 0.9 mm.

According to the present invention, since the buffer portion is joined to the base in the area of the rounded surface, the boundary portion is unlikely to come into contact with teeth or the like during the brushing, and peeling is not easily caused. 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.
According to the present invention, since the joining surface is set to 100 to 150 ° with respect to the flocked surface, it is possible to prevent the occurrence of burrs during molding.
According to the present invention, 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, so that the buffer portion and the base are bonded. Further improvement in sex can be achieved.
According to this invention, since the thickness of a buffer part is 0.1-1.0 mm, the further improvement of the adhesiveness of a buffer part and a base can be aimed at without impairing the usability of a toothbrush.
According to 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 base are not impaired without impairing the usability and flocking strength of the toothbrush. Further improvement in the adhesion can be achieved.

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.

  An embodiment 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. It is -II sectional drawing. 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. 7 has a radius of curvature R of 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 flocked hole 4 has a depth D from the flocked 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 set as the 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, and more preferably 0.2 to 0.5 mm. If it is less than 0.1 mm, there is an obstacle 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 unit 30 is a resin (low hardness resin) whose hardness measured by “JIS K6253, hardness test, test condition JIS A” is lower than the base 20, for example, the hardness measured by JIS K6253 is Preferably it is 5-100, More preferably, it is 15-90.

  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 of the buffer portion 30 on the surface 21 of the base 20 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, 0.2 to 0.8 mm is more preferable, and 0.3 to 0.7 mm is more preferable. 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), polytrimethylene terephthalate (PTT), and among them, PTT is more preferable. Since PTT easily breaks even among polyester resins, the effect of providing the buffer portion 30 appears remarkably.

  Although the thickness of a brush is not specifically limited, For example, it is set as the range of 6-11 mil (0.152-0.279mm: 1mil = 1 / 1000inch). 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 whole brush previously processed, for example in the shape of a wave, a twist shape, a jagged shape, etc. may be used, and what combined these may be used.

  Moreover, as a brush, what has the substantially same outer diameter except for the rounded part of a hair tip may be used, and the taper-shaped thing which an outer diameter becomes gradually thin as it goes to a hair tip may be used. Furthermore, the tip shape of the brush may be, for example, a spatula shape, a tapered wide shape, a spherical shape, or the like.

  The brush is planted in the flock hole 4 with a plurality of hair bundles 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 of planting a brush in 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). Note that PL is located approximately 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 line, For example, the flat thing made from brass and aluminum is mentioned.

  The dimension and shape of the flat wire can be determined in consideration of the hole 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. Further, the flat wire driving angle can be freely selected, but in order to avoid the occurrence of cracking and whitening, it is preferably in the range of 5 to 80 ° with respect to the longitudinal direction of the brush handle, more preferably 15 to 30 °. 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, according to 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 can be relieved and the occurrence of breakage 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.

  According to 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 the teeth or the like during the cleaning, and the buffer portion 30. Can be prevented from peeling or missing.

According to the present invention, since the joint surface 22 between the base 20 and the buffer portion 30 is inclined toward the outside of the head portion 2, it is possible to prevent the occurrence of burrs at the boundary portion 32 when the brush handle is formed. Further, it is possible to prevent the base 20 and the buffer part 30 from being peeled 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.
In the toothbrush 1 of the present invention, since the joint surface 22 is an inclined surface facing the outside of the head portion 2, even if the base 20 is pressed by the first split mold, the joint surface 22 is easily placed on the flock hole 4 side. It is possible to prevent a gap from being formed between the rounded surface 7 and the first split mold without being inclined. 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 that fits 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 be formed with a plurality of protrusions such as a cone shape, a pyramid shape, a columnar shape, and a prism shape, or may be ribs formed in a band shape along the joint surface. May be.

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

  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.

(Examples 1-5)
A toothbrush similar to the toothbrush 1 shown in FIG. 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 hair transplanter (manufactured by ZAHORANSKY) and driven into 23 flock holes with a flat wire (250shot) / Min).
About the produced toothbrush of each example, short shot, burr | flash generation | occurrence | production, peeling difficulty, and flocking strength were evaluated, and the result is shown in Table 1.

(Comparative Example 1)
A toothbrush was produced in the same manner as in Example 1 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, a short shot, burr | flash generation | occurrence | production, peeling difficulty, and flocking strength were evaluated, and the result is shown in Table 1.

(Comparative Example 2)
A toothbrush was produced in the same manner as in Example 1 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, a short shot, burr | flash generation | occurrence | production, peeling difficulty, and flocking strength were evaluated, and the result is shown in Table 1.

(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>
○: No chipping or deformation in the shape of the buffer portion is recognized.
(Triangle | delta): Although a big deformation | transformation was not recognized in the shape of a buffer part, a chip was seen in part.
X: A big deformation | transformation was recognized by the shape of the buffer part.

(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 of burrs was not recognized at all.
○: Burr generation was observed in an area of less than 20% of the boundary.
Δ: Generation of burrs was observed in the region of 20% or more and less than 30% of the boundary portion.
X: Generation | occurrence | production of a burr | flash was recognized in 30% or more area | region of a boundary part.

(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: No peeling could be confirmed after 200 times of use.
○: Peeling was confirmed when the number of use was 100 times or more and less than 200 times.
(Triangle | delta): Peeling was confirmed by the frequency | count of use 50 times or more and less than 100 times.
X: Peeling was confirmed when the number of use was less than 50 times.

(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>
◎: 25N or more ○: 20N or more and less than 25N △: 15N or more and less than 20N ×: 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 “◯”, evaluation of burr generation, difficulty of peeling, and flocking strength is “◯” or “」 ”.
○: Evaluation of short shot is “◯”, evaluation of burr generation, difficulty of peeling and flocking strength is “△” to “◎”, and there is one or more “△”, or evaluation of short shot Is “Δ”, and evaluation of burrs, difficulty of peeling, and flocking strength is “◯” to “◎”.
Δ: Evaluation of short shot is “Δ”, evaluation of burr generation, difficulty of peeling and flocking strength is “Δ” to “◎”, and one or more “Δ” is present, or short shot, burr There is one “x” in the evaluation of generation, difficulty of peeling and flocking strength.
X: There are two or more “x” in the evaluation of short shot, occurrence of burrs, difficulty of peeling, and flocking strength.

As shown in Table 1, in Examples 1 to 5 to which the present invention is applied, the evaluation of the occurrence of burrs is good as “◯” or “◎”, and the evaluation of the difficulty of peeling is good as “◯” or “◎”. Met. In addition, in Examples 1 to 5, the overall evaluation is “◯” or “◎”, 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 1 in which the angle of the joint surface was 180 °, the evaluation of the difficulty of peeling was “x”. In Comparative Example 2 in which the angle of the joint surface was 90 °, the short shot evaluation was “x”.
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 ease of peeling and flocking 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.

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

Claims (5)

The head portion where the brush is implanted has a rounded surface between the flocked surface where the brush is implanted and the side surface adjacent thereto, and a plurality of flocked holes are formed on the flocked surface. In the toothbrush whose peripheral part is a buffer part made 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;
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 with respect to the flocked surface.   The toothbrush according to claim 1, wherein the joint surface is an inclined surface of 100 to 150 ° with respect to the flocked surface.   The joint surface has a convex portion formed on one of the base and the buffer portion, and a concave portion fitted on the convex portion on the other side. Item 1. A toothbrush according to item 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.

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