JP2010194044A - Toothbrush and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothbrush which is an anchorless toothbrush exhibiting a high operability in an oral cavity and enables moldability, durability and loading resistance to be sufficiently ensured while increasing the quality of its design by making its handle transparent, and to provide its manufacturing method. <P>SOLUTION: The toothbrush is made by forming molten lumps at the base ends of bristle tufts 2 each of which is made of a tuft of several filaments, wherein the bristle tufts 2 are fixed with their molten lumps being buried in the head part 11, and resin composed of styrene copolymer having a flexural modulus of 1,700-3,000 MPa, a density of 1.09-1.11 g/cm<SP>3</SP>, and an MFR of 0.3-3.0 g/10 min, is used. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a toothbrush having a transparent handle in which a hair bundle is implanted in a head portion without using a flat wire, and a method for manufacturing the toothbrush.

A toothbrush that does not use a flat wire to plant the bristles in the head of the handle (hereinafter referred to as “no-flat toothbrush”) has a plurality of bristles mounted at a position corresponding to the head of the toothbrush mold. Then, after the base ends of these hair bundles are heated to form a molten lump, a synthetic resin material is injected into the mold to form a toothbrush handle, and the molten lumps of a plurality of hair bundles are formed on the head portion. Manufactured by embedding so that it cannot fall off. (For example, refer to Patent Documents 1 and 2.) This flat wire toothbrush uses a flat wire because it does not require a space for driving a flat wire and does not cause physical stress in the head. It is possible to make the head portion and the adjacent neck portion smaller as compared with the toothbrush that is provided. Therefore, it has attracted attention because it has excellent functions such as ensuring high oral cleaning properties by improving operability in the oral cavity and ensuring diversity of toothbrush designs.

On the other hand, attempts have been made to improve the designability by making the handle transparent so as to increase the acceptability of consumers. As a resin material for toothbrushes having a transparent handle, polyester resins such as polyethylene terephthalate resin, styrene resins such as AS resin, ABS resin, MS resin and methacryl resin, and polycarbonate resins are used. However, since these transparent resins have various problems, they are not used for flat wire toothbrushes. For example, polycarbonate resin and polyethylene terephthalate resin have a higher melting point than filaments usually used in toothbrushes, so when the handle of a toothbrush is molded, the molten mass of the bristles is melted and the bristles are used as a toothbrush. It cannot be fixed to the handle. Further, when molding is performed at a low temperature in order to avoid this dissolution, it is necessary to increase the injection pressure at the time of molding, and therefore the deformation of the hair bundle or the collapse of the hair bundle occurs due to the resin pressure at the time of molding. In addition, since styrenic resins generally have low durability and load resistance, there is a risk that the toothbrush handle may be broken when the toothbrush is used.

As a resin that can be used for the handle of the flat wire toothbrush, Patent Document 3 describes a resin using a thermoplastic resin having a tensile yield stress of 45 MPa or more and a flexural modulus of 1900 MPa or more. , Polybutylene terephthalate resin, polypropylene terephthalate resin, polyethylene terephthalate resin, polyethylene naphthalate resin, PCTA resin, polyester resin such as PCTG resin, polyacetal resin (homopolymer, copolymer), polycarbonate resin, aliphatic polyamide resin, aromatic polyamide resin Although the point which can employ | adopt the resin which has as a main component the resin selected from these is disclosed, even if it has these knowledge, it has not yet reached the solution of the said subject.

JP 2003-9947 A JP 2003-102552 A Japanese Patent Laid-Open No. 2006-238928

An object of the present invention is to provide a flat wire toothbrush having a transparent handle that has sufficient durability with sufficient long-term brushing and sufficient load resistance without bending due to the brushing pressure during brushing, and a method for producing the same. . More specifically, the present invention provides a flat wire toothbrush having a transparent handle that has sufficient durability and load resistance while reducing the neck portion of the toothbrush in order to improve operability in the oral cavity, and a method for manufacturing the same. It is in.

As a result of intensive studies to solve the above problems, the present inventor has a flexural modulus of 1700 MPa to 3000 MPa, a density of 1.09 g / cm ^{3 to} 1.11 g / cm ³ and an MFR of 0.3 g / 10 min. The present inventors have found that a styrene copolymer of 3.0 g / 10 min or less can be used as a resin for a transparent handle of a flat wire toothbrush, thereby completing the present invention.

Furthermore, the present inventor, as a manufacturing condition of a flat wire toothbrush having a transparent handle using the resin, by setting a gate diameter for allowing the resin to flow into the mold when the toothbrush handle is molded is 3 mm or more and 5 mm or less. We found that productivity can be secured.

That is, this invention provides the manufacturing method of the following toothbrush and toothbrush.
Item 1. A head portion, a handle portion, a head portion, and a handle in which a plurality of hair bundles are implanted by forming a molten lump at the base end portion of the hair bundle and embedding the molten lump in the head portion. In a toothbrush having a handle composed of a neck part connecting the parts, the material for the handle of the toothbrush has a flexural modulus of 1700 MPa to 3000 MPa, a density of 1.09 g / cm ^{3 to} 1.11 g / cm ³ and an MFR of 0. A toothbrush having a transparent handle, wherein a styrene copolymer having a weight of 3 g / 10 min to 3.0 g / 10 min is used.
Item 2. The toothbrush having a transparent handle according to Item 1, wherein the neck has a cross-sectional area of 15.5 mm ² or more and 25.0 mm ² or less. Item 3. A head portion, a handle portion, and a head in which a plurality of hair bundles are implanted by forming a molten lump at the proximal end portion of the hair bundle and embedding the molten lump in the head portion during handle molding In a toothbrush having a handle composed of a neck portion connecting the head portion and the handle portion, the flexural modulus is 1700 MPa to 3000 MPa, the density is 1.09 g / cm ^{3 to} 1.11 g / cm ³ , and the MFR is the handle material. A styrene copolymer of 0.3 g / 10 min to 3.0 g / 10 min is used, and the diameter of the gate for flowing the copolymer into the mold is 3 mm to 5 mm. A method of manufacturing a toothbrush having a handle.

Below, typical embodiment of the toothbrush of this invention is described.

As shown in FIG. 1 and FIG. 2, the toothbrush 1 is implanted in the head portion 11 of the handle 10 and the handle 10 including a head portion 11, a handle portion 12, a neck portion 13 that connects the head portion 11 and the handle portion 12. And a brush portion 3 composed of a plurality of bristle bundles 2 provided. As shown in FIG. 8D, the toothbrush 1 is manufactured by forming a molten lump 4 at the proximal end portion of the bristle bundle 2 formed by bundling a plurality of filaments, and forming the molten lump 4 into the molds 20 and 21. The handle 10 is molded by injecting resin into the molding space 22 in a state of being disposed in the space 22, and the plurality of hair bundles 2 are integrated with the head portion 11 so as not to fall off.

The transparent resin used for molding the handle 10 has a flexural modulus of 1700 MPa to 3000 MPa, a density of 1.09 g / cm ^{3 to} 1.11 g / cm ³ and an MFR of 0.3 g / 10 min to 3. A styrene copolymer of 0 g / 10 min or less is used. Here, the styrene copolymer is an ABS resin obtained by copolymerizing acrylonitrile and butadiene with respect to styrene, an MS resin obtained by copolymerizing a methacrylate resin, or an MBS resin obtained by copolymerizing methyl methacrylate and butadiene. This refers to variously adjusted resin physical properties by changing the ratio. For example, a resin selected from ABS resin, MS resin, and MBS resin is used. When these styrene copolymers are used as a material for a flat wire toothbrush, durability against repeated use and load resistance during use can be sufficiently secured.

Suitable transparent resins of the present invention include MBS resins copolymerized with methyl methacrylate and butadiene, and ABS resins copolymerized with acrylonitrile and butadiene. For example, IT2000, IT5200IT5300 (manufactured by Nippon Steel Chemical Co., Ltd.), Techno ABS (manufactured by Technopolymer Co., Ltd.) and the like are desirable. Among these, styrene copolymer having methyl methacrylate as a constituent element is preferable because durability is more excellent as compared with a styrene copolymer having acrylonitrile or methacrylate as a constituent element.

In addition to using the styrene copolymer as it is, it is also possible to use a resin to which a transparent colorant or a lame agent is added in order to further improve the design of the toothbrush.

The term “transparent” as used in the present invention means that “transmission of visible light can be recognized”. That is, the “transparent handle” means “a handle capable of allowing transmission of visible light”. Accordingly, a toothbrush handle or a toothbrush handle (12 or 14) obtained by using a resin mixed with a small amount of a substance that does not transmit visible light (lame, content, etc.) or by embedding a molded product and molding it. Even a so-called two-color molded toothbrush handle formed by molding an opaque resin such as an elastomer is included in the “transparent handle” as long as a visible light transmitting portion exists in the toothbrush handle portion. In particular, a flat wire toothbrush obtained by using a styrene copolymer having a transmittance value of 80% or more measured by a test method of JIS K 7105 is preferable.

There is no particular limitation on the material of the hair bundle 2 that is to be planted in the head portion 11 and that constitutes the brush portion 3. For example, polyamide resin such as nylon or aramid resin, polyethylene terephthalate, polytrimethylene terephthalate or poly Polyester resins such as butylene terephthalate, polyolefin resins such as polypropylene, thermoplastic elastomer resins, and other conventionally known thermoplastic resin filaments can be used. Furthermore, filaments having a diameter of 0.18 mm or less, deformed filaments, soft Filaments, composite material filaments and the like can also be used.

The arcuate inclined surface c (FIG. 3) has a radius of curvature R that is slightly larger than the thickness t of the head portion 11 or substantially the same as the thickness t of the head portion 11, and is preferably 1.5 mm or more and 4 mm or less. Is more preferably 1.5 mm or more and 3 mm or less.

The cross-sectional area of the neck 13 is preferably 5.5 mm ² or more and 25.0 mm ² or less, and preferably 15.5 mm ² or more and 21.0 mm from the viewpoints of the operability of the brush in the oral cavity and the durability and load resistance of the toothbrush. ² or less is more preferable. The cross-sectional area of the neck 13 in the toothbrush 1 is about 19.6 mm ² . Further, the cross-sectional shape of the neck portion 13 is not particularly limited, but the cross-sectional shape orthogonal to the axial direction of the handle 10 is preferably substantially circular from the viewpoint of operability in the oral cavity. When the cross-sectional shape of the portion connected to the portion 11 is circular, it is preferable from the viewpoint of the mechanical strength and durability of the connecting portion between the head portion 11 and the neck portion 13, and consequently the mechanical strength and durability of the toothbrush 1.

The flat wire toothbrush of this invention can be manufactured using a well-known method. In that case, the gate diameter, which is an inlet for introducing the resin into the toothbrush mold, is preferably 3 mm or more and 5 mm or less from the viewpoint of production efficiency. Here, the gate diameter refers to the inner diameter of the gate port. For example, when the shape of the gate port is circular, it means the diameter value of the inner diameter of the gate port, and when it is non-circular, it means the range from the minimum value to the maximum value of the inner diameter of the gate port. When the gate diameter is within this range, the specific styrene copolymer defined in the present invention is used even if the cross-sectional area of the neck portion of the flat wire toothbrush is reduced to 15.5 mm ² or more and 25.0 mm ² or less. If this is the case, unnecessary pressure is not applied to the molten lump at the time of molding the toothbrush handle, so that molding defects (falling of the hair bundle) due to misalignment of the molten iron do not occur. If the gate diameter is less than 3 mm, the resin hardens in the vicinity of the gate or the resin filling into the mold is slow, so the required amount of resin cannot be injected into the mold. There is a risk that defective molding is likely to occur due to deformation of the hair bundle due to the increase in the height. On the other hand, if the gate diameter exceeds 5 mm, it is not preferable because it may cause difficulty in the process of cutting off the resin in the excess portion of the gate portion or the handle may be easily broken at the gate portion. The shape of the gate opening is not particularly limited, but is preferably approximately circular or approximately elliptical. As the position of the gate in the toothbrush, if it is set to a part that contacts the oral cavity, there is a concern in terms of safety, such as damaging the oral cavity due to damage when using the toothbrush. It is preferable to set the handle portion on the side portion.

Next, another embodiment in which the configuration of the toothbrush 1 is partially changed will be described. The same members as those in the above embodiment are given the same reference numerals, and detailed description thereof is omitted.

As in the toothbrush shown in FIG. 6, instead of the head portion 11, the head main body 30 integrally formed with the handle 10 </ b> A and the handle 10 </ b> A are made of different members, and are laminated on the flocked surface side of the head main body 30. It is also possible to provide a head portion 11A comprising the cover member 31 provided on the head. When the toothbrush 1A is molded, as shown in FIG. 10E, the cover member 31 is disposed in the molding space 22A for molding the head portion 11A, and the flock hole 32 of the cover member 31 is inserted. In the state where the hair bundle 2 formed by bundling a plurality of filaments is arranged, the molten mass 4 is formed at the proximal end of the hair bundle 2, and the molten mass 4 is arranged in the molding space 22A. The synthetic resin material is injected into the handle 10A, and the plurality of hair bundles 2 are integrally embedded in the head portion 11A so as not to drop off.

In this toothbrush 1A, the synthetic resin material constituting the handle 10A and the filament can be the same as in the above embodiment. Moreover, as a material of the cover member 31, a synthetic resin or a thermoplastic elastomer can be adopted, and it does not matter whether it is transparent or opaque. In particular, a synthetic resin or a thermoplastic elastomer having compatibility with the material of the handle 10A can be suitably used. If the thickness of the cover member 31 is too thin, the molten resin flows out of the cover member 31 through the gap between the filaments to cause molding defects, and if it is too thick, the operability of the brush part 3 in the oral cavity decreases. Therefore, it is preferable to set to 0.5 or more and 3.5 mm or less. In this toothbrush 1A, the thickness of the head main body 30 formed integrally with the handle 10A can be set to 1.5 mm or more and 4 mm or less.

ADVANTAGE OF THE INVENTION According to this invention, the toothbrush which has a transparent handle formed by implanting a hair | bristle bundle without using a flat line in a head part can be provided. More specifically, a flat wire toothbrush having a neck portion excellent in operability in the oral cavity and a transparent handle excellent in design can be provided.

Toothbrush front view Top view of toothbrush Enlarged front view of the main part from the head part to the neck part of the toothbrush The enlarged plan view of the principal part from the head part of the toothbrush to the neck part VV line sectional view of FIG. Perspective view of toothbrush with other configuration

As the resin material of the handle 10, eight types of styrene copolymers (MBS, ABS, MS) shown in Table 1 were used. The physical properties of these resin materials are as shown in Table 2. Further, as the hair bundle 2, a hair bundle 2 in which 50 filaments made of nylon having a diameter of 0.19 mm were bundled was used. And, in the state where the molten lump 4 having a diameter of 1.7 mm to 2 mm and a thickness of 0.2 mm to 1 mm is formed at the proximal end portion of the hair bundle 2, and this molten lump 4 is arranged in the molding space 22, At the molding temperature shown in Table 2 and Table 3, a synthetic resin material is injected into the molding space 22 to mold the handle 10, and a plurality of hair bundles 2 are integrally implanted in the head portion 11 so as not to fall off. 1 to 5, and eight types of toothbrushes 1 were prepared in which the dimensions of each part were shown in parentheses in FIGS. 1 and 3 to 5. The molding temperature was set by performing molding at a plurality of different molding temperatures in advance so that a defective filling of the synthetic resin material does not occur at the tip of the head portion 11 and the molding temperature is as low as possible.

Next, durability evaluation was performed on the toothbrush 1A molded with the above eight types of resins, and further, load resistance (handle bending test) was evaluated for the resins whose durability test results were evaluated as ◎ or ○. Overall evaluation was performed from the evaluation results. Furthermore, the evaluation of the feasibility of forming the toothbrush handle in the product of the present invention was performed. Each test method and criteria are shown below, and each evaluation result is shown in Table 2 and Table 3. The test method for resin characteristics in the table was as follows.
* 1 Flexural modulus JIS K 7171
* 2 Transmittance JIS K 7105
* 3 Density JIS K 7112
* 4 MFR JIS K 7210

<Evaluation of Durability> With the handle 12 fixed and held and the handle 10 supported in a substantially horizontal cantilever shape, 1 kg of stress is applied to the center of the head 11 at a cycle of 4 times per second. In addition, the number of stresses applied until the neck 13 is finally broken is measured.
Judgment criteria ◎ 60000 times or more ○ 30000 times or more and less than 60000 times × less than 30000 times

<Evaluation of Load Resistance (Handle Bending Test)> With the handle 12 fixed and held and the handle 10 supported in a substantially horizontal cantilever shape, the handle deforms stress at the center of the head 11. Or it continued by adding until it fractured. Judgment criteria are shown below.
Judgment criteria ○ Do not break × Break

<Comprehensive judgment>
◎ Durability evaluation result is ◎ and load resistance evaluation result is ○ ○ Durability evaluation result and load resistance evaluation result are both ○ × Other than above

<Evaluation of toothbrush handle molding>
○ The hair bundle 2 is not tilted at all, the molten soul 4 is not melted and deformed, and the shape of the hair bundle 2 is hardly changed after being molded. That are not deformed and that have little shape change after molding × Other than the above

As shown in Tables 2 and 3, even for the same styrene copolymer, the flexural modulus is 1700 MPa to 3000 MPa, the density is 1.09 g / cm ^{3 to} 1.11 g / cm ³ and the MFR is 0.00. It is apparent that a resin that does not satisfy the condition of 3 g / 10 min or more and 3.0 g / 10 min or less is insufficient in durability and load resistance. Also, it is clear that the gate diameter is in the range of 3 mm to 5 mm under manufacturing conditions. In addition, it was judged that the gate diameter was 6 mm because it was difficult to cut the gate portion or the handle was easily broken at the gate portion.

Furthermore, since the styrene copolymer made of MBS resin containing methyl methacrylate as a constituent component is superior in durability to the styrene copolymer (D) made of ABS resin containing acrylonitrile as a constituent component, it is the most preferable implementation. Can be determined.

According to the present invention, it is possible to provide a flat wire toothbrush having a transparent handle excellent in design, having both durability with sufficient long-term brushing and sufficient load resistance without bending due to the brushing pressure during brushing.

DESCRIPTION OF SYMBOLS 1, 1A Toothbrush 2 Hair bundle 3 Brush part 4 Molten soul 10, 10A Handle 11, 11A Head part 12 Handle part 13 Neck part 30 Head main-body part 31 Cover member a Flocked surface b Back side c Inclined surface d Connection part

Claims (3)

A molten lump is formed at the proximal end of the hair bundle, and the molten lump is embedded in the head portion to thereby have a head portion in which a plurality of hair bundles are implanted, a handle portion, a head portion, and a handle portion. In a toothbrush having a handle composed of a neck part to be connected, the material of the handle of the toothbrush is a bending elastic modulus of 1700 MPa to 3000 MPa, a density of 1.09 g / cm ^{3 to} 1.11 g / cm ³ and an MFR of 0.3 g / A toothbrush having a transparent handle, characterized by using a styrene copolymer of 10 min to 3.0 g / 10 min. The toothbrush having a transparent handle according to claim 1, wherein a cross-sectional area of the neck is 15.5 mm ² or more and 25.0 mm ² or less. A head portion, a handle portion, a head portion, and a handle in which a plurality of hair bundles are implanted by forming a molten lump at the base end portion of the hair bundle and setting the molten lump to a head portion when the handle is molded. In a toothbrush having a handle composed of a neck part connecting the parts, the flexural modulus of the handle is 1700 MPa to 3000 MPa, the density is 1.09 g / cm ^{3 to} 1.11 g / cm ³ and the MFR is 0.3 g. A transparent handle is used, wherein a styrene copolymer having a size of / 10 min to 3.0 g / 10 min is used, and a gate diameter for flowing the copolymer into the mold is 3 mm to 5 mm. Toothbrush manufacturing method.

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