JP2007000519A - Toothbrush bristle and toothbrush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toothbrush bristle having high bending recovery, breakage resistance and brush durability and a toothbrush using the same.
SOLUTION: Toothbrush bristles 10 having a core-sheath structure provided with a core part 11 and at least two or more resin layers 12 concentrically covering the core part 11, wherein the core part 11 is a polytri. Methylene terephthalate (PTT) is included, the outermost layer 13 of the resin layer 12 includes a polyester resin excluding PTT, and the intermediate layer 14 interposed between the outermost layer 13 of the resin layer 12 and the core portion 11 is the outermost layer. 13 and the core part 11 are prevented from delamination.
[Selection] Figure 3

Description

  The present invention relates to a toothbrush bristle having a multilayer structure (core-sheath structure) in which two or more resin layers are concentrically coated on a core part, and a toothbrush using the toothbrush bristles.

  Conventionally, nylon, polybutylene terephthalate (PBT), and the like are used as the material for the toothbrush bristle. These materials have high bend recovery (brush durability), and there is no brittle fracture (breakage) due to significant chemical changes or tearing due to scratches even during continuous use with dentifrices. Since it is inexpensive, it is widely used as a toothbrush bristle.

  Further, as toothbrush hair having high brush durability, those using polytrimethylene terephthalate (PTT) are known. However, PTT is inferior to the above-mentioned nylon, PBT, and the like, when it is damaged or excessively immersed in chemicals. For this reason, the toothbrush hair using PTT has a problem that it breaks from a minute scratch and may not endure use as a toothbrush hair.

  On the other hand, in order to improve the breaking strength, it has been proposed to have a so-called core-sheath structure in which the surface of the brush (filament) is coated with a different resin. However, in the case of this core-sheath structure, the surface layer of the resin may be peeled off due to repeated cleaning, which has a problem in durability. Further, when manufacturing a toothbrush bristle having such a special structure, since it is difficult to manufacture with the conventional spinning equipment, a new capital investment is required. In this case, since the manufacturing efficiency is also reduced, there is a problem that the manufacturing cost is increased.

  Thus, since the toothbrush hair using PTT is more delicate than the toothbrush hair using nylon or PBT described above, the improvement in the damage resistance of the toothbrush hair using this PTT has been almost the same. The current situation has not been examined.

In addition, as a well-known document relevant to this invention, there exist the following patent documents 1-5, for example.
Patent Document 1 describes a brush bristle material comprising a monofilament bristle obtained by mixing and spinning a polypropylene terephthalate (same as PTT) and a polyester resin other than polypropylene terephthalate. However, although the present invention is a PTT mixing hair that has been studied to achieve both bristle waist (flexibility) and durability (bending recovery property), it does not improve hair breakage.

  Patent Document 2 describes a toothbrush having a filament made of a co-extruded product of a filament containing PTT and PTT and another polymer material (such as nylon). However, the present invention is intended to moderately control the bending rigidity and bending recovery of the filament, and not to improve the breakage resistance of the PTT. Further, if the PTT and another polymer material are simply combined as in the present invention, delamination occurs due to repeated brushing, which makes it difficult to use for a toothbrush filament.

  Patent Document 3 describes a brush for a brush having a core-sheath multilayer structure in which a filament is formed of a plurality of different materials and one material is covered with the other material. However, this invention does not solve the problem of delamination in repeated cleaning.

  Patent Document 4 describes a toothbrush in which sea-island type composite fibers in which 2 to 5 island parts made of polyamide resin are scattered in a polyester resin sea part are planted. However, this invention is not made at all about the examination of PTT.

Patent Document 5 describes a toothbrush that is a string bristle in which a plurality of fine yarns are knitted around a core material by string making. The present invention aims to improve breakage due to scratches on the PTT used for the core material and to improve plaque removal power due to the string-like surface layer. The structure is easy to break and it does not fundamentally solve the problem of broken hair. Further, when a polyamide resin is used for the string, there is a problem that the surface layer peels off early because it is not welded to the core PTT. Furthermore, since the structure is complicated and fine, it cannot be produced by a normal monofilament manufacturing facility, and an increase in cost is avoided.
JP 2004-141504 A JP 2001-511379 A Japanese Utility Model Publication No. 60-83338 Japanese Patent Laid-Open No. 9-322821 JP 2004-81647 A

  Therefore, the present invention has been proposed in view of such conventional circumstances, and provides a toothbrush bristle having high bending recovery, breakage resistance and brush durability, and a toothbrush using the same. With the goal.

In order to achieve this object, the invention described in claim 1 includes a core portion and at least two or more resin layers covering the core portion concentrically, and the core portion is made of polytrimethylene terephthalate (PTT). ), And the outermost layer of the resin layer contains a polyester resin excluding PTT, and an intermediate layer interposed between the outermost layer of the resin layer and the core portion prevents delamination between the outermost layer and the core portion. It is the hair for toothbrushes characterized by doing.
The invention according to claim 2 is the toothbrush bristle according to claim 1, wherein the intermediate layer is made of a polymer alloy of PTT and a polyester resin.
The invention according to claim 3 is the toothbrush bristle according to claim 1 or 2, wherein the intermediate layer has a thickness of 2 to 20 μm.
The invention according to claim 4 is the toothbrush bristle according to any one of claims 1 to 3, wherein the resin layer has a thickness of 10 to 30 μm.
The invention according to claim 5 is the toothbrush bristle according to any one of claims 1 to 4, wherein the intermediate layer contains PTT in a proportion of 30 to 70% by weight.
A sixth aspect of the present invention is a toothbrush characterized by using the toothbrush bristle according to any one of the first to fifth aspects.

As described above, according to the present invention, the intermediate layer interposed between the core portion and the outermost layer prevents delamination between the core portion and the outermost layer. While using high PTT to improve the breaking strength of toothbrush bristle, it is possible to obtain high bending recovery and breakage resistance of toothbrush bristle by using a polyester resin excluding PTT as the outermost layer.
Moreover, since this toothbrush bristle can be easily manufactured with a normal coextrusion molding machine, an increase in the manufacturing cost of the toothbrush using this toothbrush bristle can be suppressed.

Hereinafter, a toothbrush bristle to which the present invention is applied and a toothbrush using the same will be described in detail with reference to the drawings.
For example, the toothbrush 1 shown in FIG. 1 has a head portion 3 in which a bristle bundle 2 is implanted, a grip portion 4 that a user grips, and a neck portion 5 that connects the head portion 3 and the grip portion 4. It is configured. The hair bundle 2 is formed by implanting a bundle of a plurality of brushes (filaments) into a plurality of flock holes provided on a flocking table of the head unit 3 with a flat wire or by heat fusing. It is). And the toothbrush hair (filament) to which the present invention to be described later is applied can be used as a part or all of the bristle bundle 2 of the toothbrush 1.

  In addition, the toothbrush 1 is not necessarily limited to the shape and form shown in FIG. 1, The shape can be changed suitably. Moreover, like the electric toothbrush, at least the flocking part (replacement toothbrush) constituting the head part 3 may be detachable (replaceable) with respect to the main body part constituting at least the grip part 4.

  The toothbrush bristle to which the present invention is applied is a filament 10 made of a co-extruded product as shown in FIG. 2, and the cross section thereof is a core part 11 and the core part 11 concentrically as shown in FIG. It has a multilayer structure (core-sheath structure) including at least two or more resin layers 12 to be coated.

  Of each layer constituting the toothbrush bristle 10, the core 11 is made of polytrimethylene terephthalate (PTT) in order to obtain a brush (filament) having high brush durability (bending recovery). In addition, in order to ensure basic damage resistance and chemical resistance, it is usually preferred to use a PTT having a limiting viscosity of 1.0 or more, but in the case of the toothbrush hair of the present invention, Since the surface of the core 11 is covered with the resin layer 12, there is no need to provide any particular restriction.

  On the other hand, the outermost layer 13 which is the surface layer of the resin layer 12 is made of a polyester-based resin excluding PTT in order to cover and protect the core portion 11 while securing an appropriate fluff. Examples of the polyester resins include polyester elastomers, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), and the like, and one or more of these can be used. In addition, when materials other than polyester-type resins, such as nylon, are used for the outermost layer 13, since physical properties differ greatly from PTT, it becomes very difficult to ensure adhesiveness with this PTT.

  On the other hand, the intermediate layer 14 interposed between the outermost layer 13 of the resin layer 12 and the core portion 11 is for preventing delamination between the outermost layer 13 and the core portion 11 and includes at least one layer. It is provided above. For the intermediate layer 14, a polymer alloy of PTT and a polyester resin is used in order to enhance the compatibility (adhesion) between the polyester resin of the outermost layer 13 and the PTT of the core 11.

  Specifically, the intermediate layer 14 preferably contains 30 to 70% by weight of PTT, more preferably 50%. Thus, a layer having enhanced compatibility (adhesiveness) between PTT and polyester resin is interposed between the core portion 11 and the outermost layer 13, and delamination between the core portion 11 and the outermost layer 13 is performed. And stable adhesion can be obtained.

  Further, when a plurality of intermediate layers 14 are laminated, the blending ratio of PTT is changed stepwise between the layers constituting the intermediate layer 14 (specifically, the PTT of each layer as it approaches the core 11). By increasing the content, higher interlayer adhesion strength can be obtained. Further, a compatibilizing agent can be added to the intermediate layer 14 in order to obtain a more stable and strong adhesive quality. The compatibilizer is not particularly limited as long as it improves the dispersion and compatibility of the polyester resin, and for example, an acrylic / sulfone polymer having an epoxy group can be used.

  As for the cross-sectional shape of the toothbrush bristle 10 to which the present invention is applied, a circular shape is most preferable in order not to concentrate stress locally and to have a uniform bending balance, but it may be changed to any shape according to the purpose. it can. Further, the coloring of the toothbrush bristle is not particularly limited, and it may be a single color or the color of each layer may be changed.

  The diameter of the toothbrush bristles 10 to which the present invention is applied is preferably in the range of 150 to 300 μm, and the diameter of the core 11 is preferably in the range of 100 to 280 μm. The ratio of the diameter of the core 11 to the diameter of the toothbrush bristle is preferably in the range of 60 to 95%. When the ratio of the core part 11 is less than 60%, high brush durability cannot be obtained. On the other hand, when the ratio of the core part 11 exceeds 95%, it becomes difficult to adhere to the relatively thin resin layer 12. Not only that, the outermost layer 13 becomes thinner, so that the centering of the core portion 11 becomes difficult.

  The thickness of the resin layer 12, that is, the total thickness of the outermost layer 13 and the intermediate layer 14 is preferably in the range of 10 to 30 μm. Of these, the thickness of the outermost layer 13 is preferably in the range of 5 to 25 μm, more preferably 10 to 20 μm. When the thickness of the outermost layer 13 is less than 5 μm, the layer thickness is not stable and more easily peeled, while when the thickness of the outermost layer 13 exceeds 25 μm, the cross-sectional volume of the core 11 is relatively reduced, Brush durability is reduced.

  The thickness of the intermediate layer 14 is preferably in the range of 2 to 20 μm. The thickness of the intermediate layer 14 is preferably as thin as possible as long as adhesion is ensured. However, if the thickness is too thin, the stability of the layer thickness is insufficient and the original function is not achieved. The volume is reduced, and the brush durability is reduced.

  As described above, in the toothbrush bristle 10 to which the present invention is applied, delamination between the core portion 11 and the outermost layer 13 is prevented by the intermediate layer 14 interposed between the core portion 11 and the outermost layer 13. Therefore, it is possible to obtain high bending recovery and breakage resistance by using a polyester-based resin excluding PTT for the outermost layer 13 while improving the breaking strength using PTT having high brush durability for the core 11. it can.

  Moreover, since this toothbrush bristle 10 can be easily manufactured with a normal coextrusion molding machine, an increase in the manufacturing cost of the toothbrush 1 using this toothbrush bristle 10 can also be suppressed. For example, in the case of a flat wire type toothbrush, a plurality of pieces are bundled into a cut piece having a predetermined length (for example, 30 mm). This cut piece is set on a flat wire type flocking machine, an arbitrary number (about 15 to 40 pieces) is picked, and folded into a flocking hole of the head part 3 together with a brass flat wire. Then, the said toothbrush 1 can be obtained by trimming the hair | bristle bundle 2 planted by the flocking hole in arbitrary shapes, and carrying out the rounding finish of a hair tip then. Even in the case of a flat-wireless toothbrush, for example, the toothbrush bristles 10 to which the present invention is applied can be implanted into the toothbrush 1 by using a conventionally known method such as supplying a hair bundle from a bristle reel. it can. As described above, the toothbrush bristles 10 to which the present invention is applied can select a flocking machine regardless of the flat line type or the flat line-less type, and is very versatile.

Hereinafter, the effects of the present invention will be made clearer by examples. In addition, this invention is not limited to a following example, In the range which does not change the summary, it can change suitably and can implement.
Example 1
In Example 1, as shown in FIG. 4A, PTT (limit viscosity 0.8) was mixed with the core 11, and PTT and a polyester elastomer (Hytrel manufactured by Toray) were mixed at a ratio of 1: 1 to the intermediate layer 14. Toothbrush bristle having a three-layer core-sheath structure using a polyester alloy as the polymer alloy and outermost layer 13 was produced, and a toothbrush in which the toothbrush bristles were implanted was produced.

  Specifically, when producing the toothbrush of Example 1, first, each of the above resins was melt-spun using a coextrusion molding machine, extruded into water, cooled and solidified, and then heated at 60 ° C. in the first stage. In the second stage, the film was stretched 4 to 5 times in a dry atmosphere at 120 ° C., and then subjected to a relaxation heat set in a dry heat atmosphere, and then wound on a bobbin to obtain a fiber having a diameter of 200 μm. . At this time, the core 11 had a diameter of 170 μm, the intermediate layer 14 had a thickness of 5 μm, and the outermost layer 13 had a thickness of 10 μm. Next, after this fiber was converged with a wrapping paper to a bundle diameter of 45 mm, the hair bundle was cut into cut pieces having a length of 30 mm. Next, the cut piece from which the wrapping paper has been removed is set on a hair plate of a flat wire type flocking machine (ZT-1TC made by Zahoransky), 18 pieces are bundled by a picker, and the central part is folded in half and then the flat wire is attached. Then, it was driven into a flock hole (hole diameter: 1.5 mm, 8 rows × 3 columns) provided in the head portion of the toothbrush. Next, the hair bundle was trimmed to a hair length of 10 mm, and finally the bristles were rounded to obtain the toothbrush of Example 1.

(Example 2)
In Example 2, as shown in FIG. 4B, the core 11 has a PTT (limit viscosity of 0.8), the intermediate layer 14 has a polymer alloy in which PTT and PBT are mixed at a ratio of 1: 1, and the outermost layer 13 has a PBT. The toothbrush bristle which consists of a 3 layer core sheath structure using this was produced, and the toothbrush which transplanted this toothbrush bristle was produced.

  Specifically, when preparing the toothbrush of Example 2, first, each of the above resins was melt-spun using a co-extrusion molding machine, extruded into water, cooled and solidified, and then heated at 60 ° C. in the first stage. In the second stage, the film was stretched 4 to 5 times in a dry atmosphere at 120 ° C., and then subjected to a relaxation heat set in a dry heat atmosphere, and then wound on a bobbin to obtain a fiber having a diameter of 200 μm. . At this time, the diameter of the core 11 was 140 μm, the thickness of the intermediate layer 14 was 10 μm, and the thickness of the outermost layer 13 was 20 μm. Next, after this fiber was converged with a wrapping paper to a bundle diameter of 45 mm, the hair bundle was cut into cut pieces having a length of 30 mm. Next, the cut piece from which the wrapping paper has been removed is set on a hair plate of a flat wire type flocking machine (ZT-1TC made by Zahoransky), 18 pieces are bundled by a picker, and the center part is folded in half, and then with the flat line Then, it was driven into a flock hole (hole diameter: 1.5 mm, 8 rows × 3 columns) provided in the head portion of the toothbrush. Next, the hair bundle was trimmed to a hair length of 10 mm, and finally the hair ends were rounded to obtain the toothbrush of Example 2.

(Example 3)
In Example 3, as shown in FIG. 4C, PTT (limit viscosity 1.3) is formed on the core 11 and PTT and a polyester elastomer (Hytrel manufactured by Toray) are formed on the inner intermediate layer 14a in a ratio of 7: 3. A mixed polymer alloy, a polymer alloy in which PTT and a polyester elastomer (Hytrel manufactured by Toray) are mixed in a ratio of 3: 7 to the outer intermediate layer 14b, and a four-layer core-sheath structure using a polyester elastomer in the outermost layer 13 The toothbrush bristle which consists of was produced, and the toothbrush which planted this bristle for toothbrush was produced.

  Specifically, when producing the toothbrush of Example 3, first, each of the above resins was melt-spun using a coextrusion molding machine, extruded into water, cooled and solidified, and then heated at 60 ° C. in the first stage. In the second stage, the film was stretched 4 to 5 times in a dry atmosphere at 120 ° C., and then subjected to a relaxation heat set in a dry heat atmosphere, and then wound on a bobbin to obtain a fiber having a diameter of 200 μm. . At this time, the core 11 had a diameter of 160 μm, the inner intermediate layer 14 a had a thickness of 5 μm, the outer intermediate layer 14 b had a thickness of 5 μm, and the outermost layer 13 had a thickness of 10 μm. Next, after this fiber was converged with a wrapping paper to a bundle diameter of 45 mm, the hair bundle was cut into cut pieces having a length of 30 mm. Next, the cut piece from which the wrapping paper has been removed is set on a hair plate of a flat wire type flocking machine (ZT-1TC made by Zahoransky), 18 pieces are bundled by a picker, and the central part is folded in half and then the flat wire is attached. Then, it was driven into a flock hole (hole diameter: 1.5 mm, 8 rows × 3 columns) provided in the head portion of the toothbrush. Next, the hair bundle was trimmed to a hair length of 10 mm, and finally the hair ends were rounded to obtain a toothbrush of Example 4.

(Comparative Examples 1-4)
In Comparative Example 1, a toothbrush similar to Example 1 was prepared except that toothbrush bristles made of PTT (limit viscosity 0.8) were used.
In Comparative Example 2, a toothbrush similar to Example 1 was produced in Comparative Example 1, except that toothbrush bristles made of PTT (limit viscosity 1.5) were used.
In Comparative Example 3, Example 1 was used except that toothbrush bristles having a two-layer core-sheath structure using a PTT having a diameter of 180 μm as the core and a PBT having a thickness of 10 μm as the outermost layer were used. A similar toothbrush was produced.
In Comparative Example 4, a toothbrush similar to Example 1 was produced except that toothbrush bristles made of nylon 612 were used.

And about each toothbrush of these Examples 1-3 and Comparative Examples 1-4, each evaluation test of a broken hair, surface layer peeling, and a bending recovery property was done. The evaluation results are shown in Table 1. In this evaluation test, each toothbrush was reciprocated using a model cleaning tester, and then the state of the toothbrush bristles of each toothbrush was observed and evaluated. The test conditions using the model cleaning tester are as follows.
Load: 500g
Stroke: 20mm
Speed: 150rpm / min
Number of brushes: 200,000 times Repeat number: 6 times

In addition, among the evaluation items, for the broken hair, the root of the toothbrush hair, the middle break, and the check-up were confirmed. For surface peeling, delamination was confirmed at the tips and roots of the toothbrush bristles. About bending recovery property, the state of the hair opening was confirmed. The evaluation criteria shown in Table 1 are as follows.
A: “Very good”
○: “Good”
△: “Neither”
×: “Bad”

From the evaluation results shown in Table 1, about the broken hair, as in Comparative Examples 1 and 2, when the toothbrush hair is composed only of PTT, the difficulty of breaking the hair changes due to the limiting viscosity, which becomes unstable. As in Examples 1 to 3, it was found that if a core-sheath structure in which the core portion made of PTT is covered with the intermediate layer and the outermost layer, the breakage is improved regardless of the limiting viscosity of PTT.
For surface peeling, as in Comparative Example 3, in the case of a two-layer core-sheath structure in which a core portion made of PTT is coated with an outermost layer made of PBT, the outermost layer (PBT) cannot withstand 200,000 times of brushing. However, as in Examples 1 to 3, it was found that the surface peeling of the outermost layer was improved by interposing an intermediate layer between the core portion made of PTT and the outermost layer.
About bending recovery property, it turned out that a higher bending recovery property is obtained by using PTT for a core part like Examples 1-3 than the case where nylon is used like the comparative example 4. FIG.
From the above, it has been clarified that in the toothbrush to which the present invention is applied, breakage and surface peeling of the toothbrush hair are improved and sufficient bending recovery of the toothbrush hair is obtained.

FIG. 1 is a side view showing an example of a toothbrush using toothbrush bristles to which the present invention is applied. FIG. 2 is an enlarged side view showing a main part of a toothbrush to which the present invention is applied. 3 is a cross-sectional view of the toothbrush bristle to which the present invention is applied, taken along line X-X 'in FIG. 4A is a cross-sectional view showing the core-sheath structure of the toothbrush bristle of Example 1, FIG. 4B is a cross-sectional view showing the core-sheath structure of the toothbrush bristle of Example 2, and FIG. It is sectional drawing which shows the core-sheath structure of the bristle for 3 toothbrushes.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Toothbrush 2 ... Hair bundle 3 ... Head part 4 ... Gripping part 5 ... Neck part 10 ... Hair (filament) for toothbrush 11 ... Core part 12 ... Resin layer 13 ... Outermost layer 14 ... Middle layer

Claims (6)

A toothbrush bristle comprising a core part and at least two resin layers covering the core part concentrically,
The core includes polytrimethylene terephthalate (PTT);
The outermost layer of the resin layer includes a polyester resin excluding the PTT,
A toothbrush bristle characterized in that an intermediate layer interposed between the outermost layer and the core of the resin layer prevents delamination between the outermost layer and the core.   2. The toothbrush bristles according to claim 1, wherein the intermediate layer is made of a polymer alloy of the PTT and the polyester resin.   The toothbrush bristles according to claim 1 or 2, wherein the intermediate layer has a thickness of 2 to 20 µm.   The toothbrush bristles according to any one of claims 1 to 3, wherein the resin layer has a thickness of 10 to 30 µm.   The toothbrush bristles according to any one of claims 1 to 4, wherein the intermediate layer contains the PTT in a proportion of 30 to 70% by weight.   A toothbrush using the toothbrush bristle according to any one of claims 1 to 5.

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