JP2006340748A - Bristle for toothbrush and toothbrush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bristle for a toothbrush of a sea-island structure using a PPT (polytrimethylene terephthalate) resin for a sea part and having a high bending recovery and shatter resistance and to provide a toothbrush using the same. <P>SOLUTION: Island fibers 3 composed of a polyamide resin are disposed in a sea part 2 composed of a polytrimethylene terephthalate (PTT) resin along the outer circumference of the sea part at an approximately equal interval. The shortest distance (m) between the island fiber and the bristle surface is defined to 10-30 μm and the shortest distance (n) between the island fibers is defined within a range of 10-50 μm. The cross sectional shape of the island fiber 3 is either of a circle or an ellipse and the elliptical cross-section island fiber is so disposed that the direction of the long axis of the elliptical cross section is approximately accorded with the tangential direction of a concentric circle drawn around a bristle axis. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a toothbrush bristle having a sea-island structure using polytrimethylene terephthalate (PTT) resin in the sea and a toothbrush using the same.

  Conventionally, nylon, polybutylene terephthalate (PBT) resin, etc. are widely known as toothbrush bristles. They have high bend recovery (brush durability), and do not cause brittle fracture (breakage) due to significant chemical changes or cracks due to scratches even during continuous use with dentifrices, and are inexpensive. Is widely used as toothbrush bristle.

  Furthermore, those using PTT resin are known as toothbrush bristles with high brush durability. However, the hair made of PTT resin is also known in Patent Document 4 (Japanese Patent Application Laid-Open No. 2004-81647) “It is known that if a micro-scratch is applied to the filament, it will be broken” (see paragraph 0009). ), The problem was that it was more delicate and difficult to handle than nylon and PBT hair. However, at present, little consideration has been given to improving the breakage resistance of PTT hair.

Below, some examples of the toothbrush bristle conventionally used are given.
a. Patent Document 1 (Japanese Utility Model Publication No. 60-83338)
Hair for sea-island structure in which filaments are formed from a plurality of different materials and two or more core materials are embedded in the sheath material in an isolated state. The hair material is characterized by being arbitrarily selected and combined from a group consisting of polyamide, polyester, and other resins. However, no PTT is used in this hair, and no studies have been made to solve the above problems in PTT hair.

b. Patent Document 2 (Japanese Patent Laid-Open No. 9-322821)
Hair having a sea-island structure in which 2 to 5 island parts made of polyamide resin are scattered in the sea part of the polyester resin, and only the island fibers are exposed on the hair end side. It is possible to provide a toothbrush having a high ability to remove plaque even though it is soft against the gingiva and does not feel pain. In this case as well, PTT has not been studied at all. Expected effects are also different. Further, since the island fibers are exposed at the hair tip, not only the durability of the brush is sacrificed, but also the ability to scrape off the tooth surface is inferior.

c. Patent Document 3 (Japanese Patent Publication No. 2001-511379)
A filament that is a filament containing PTT resin or a coextruded product made of PTT resin and another polymer (such as nylon). This filament is for moderately controlling the bending rigidity and bending recovery property of the filament, and is not for improving the damage resistance of the PTT. Moreover, examination about a coextruded product is only the hair of a core sheath structure. The combination of PTT resin and nylon in this core-sheath structure causes surface layer peeling and is difficult to use as a filament for a toothbrush.

d. Patent Document 4 (Japanese Patent Laid-Open No. 2004-81647)
A string bristle in which a plurality of fine yarns are knitted around the core made of PTT resin by stringing. This string bristle aims to improve breakage due to scratches on the PTT resin and to improve plaque removal by the string-like surface layer. It is easy to tear and is not a fundamental measure against broken hair. Further, in the case of a polyamide resin string, since it does not weld to the PTT resin, there is also a drawback that the surface layer peels off early. Furthermore, since the structure of the hair itself is complicated and fine, it is difficult to manufacture, and it cannot be produced by a normal monofilament manufacturing facility.

e. Patent Document 5 (Japanese Patent Laid-Open No. 2004-141504)
A monofilament obtained by melting and spinning a polypropylene terephthalate resin (another name for PTT resin) and a polyester resin other than polypropylene terephthalate. This filament is a PTT mixing hair that has been studied to achieve both bristle waist (flexibility) and durability (bending recovery property), but does not improve the breakage that is a problem of the present invention.

Japanese Utility Model Publication No. 60-83338 (all pages, all figures) JP-A-9-322821 (all pages, all figures) JP-T-2001-511379 (all pages, all figures) JP 2004-81647 A (all pages, all figures) JP 2004-141504 A (all pages, all figures)

In the case of toothbrush bristles using conventional PTT resin, there are the following problems.
That is, PTT resin is inferior to a flaw when subjected to scratches or excessive chemical immersion compared to conventional resin filaments such as nylon and PBT, and may not endure use as a toothbrush. In addition, when taking a special structure to improve the breaking strength of PTT resin, it is difficult to manufacture only with conventional spinning equipment, new capital investment is required, and manufacturing efficiency is also reduced. Cost (cost) will increase.

  The present invention has been made to solve the above problems, and provides a toothbrush bristle having a sea-island structure with high bending recovery and breakage resistance using a PTT resin in the sea, and a toothbrush using the same. It is the purpose.

  In order to achieve the above object, the toothbrush bristle 1 of the present invention has an island fiber 3 made of polyamide resin in a sea part 2 made of polytrimethylene terephthalate (PTT) resin, as illustrated in FIGS. Are arranged at substantially equal intervals along the outer periphery of the sea part 2. Further, the toothbrush of the present invention is characterized in that the toothbrush bristle 1 of the present invention having the above structure is implanted.

  It should be noted that the island fiber 3 is not exposed or peeled off during use of the toothbrush, and so that the crack does not extend to the inside of the bristle even when a crack occurs in the surface layer of the PTT resin constituting the sea portion 2. It is desirable that the shortest distance between the fibers and the bristle surface (the shortest distance between adjacent portions of the island fibers 3 and the surface of the toothbrush bristle 1) m is in the range of 10 to 30 μm. Further, the shortest distance between island fibers (the shortest distance between adjacent neighboring fibers 3, 3) n is preferably in the range of 10 to 50 μm.

  Furthermore, the cross-sectional shape of the island fiber 3 is either circular or elliptical, and the island fiber having an elliptical cross section is oriented in the major axis direction of the elliptical cross section as shown in FIGS. Is preferably arranged so as to substantially coincide with the tangential direction of the concentric circle c drawn around the hair shaft core.

  Since the polyamide resin constituting the island fiber 3 has low compatibility with the PTT resin, the island fiber 3 is completely embedded in the sea part 2 made of PTT resin, and the island fiber 3 is exposed from the outer peripheral surface of the sea part 2. Make sure there is nothing.

1. Material and cross-sectional shape of bristle The sea part 2 constituting the bristle base part is made of PTT resin in order to obtain a filament having high brush durability (bending recovery property). A PTT resin having a critical viscosity of 1.0 or more is used in order to ensure basic damage resistance and chemical resistance. The island fiber 3 embedded in the sea part 2 is made of a polyamide resin excellent in bending recovery and chemical resistance. Nylon 612 and nylon 610 are preferably used. The cross-sectional shape of the toothbrush bristle 1 composed of the sea-island structure of the sea part 2 and the island fiber 3 is most preferably a circular cross-section because it has a uniform bending balance without local stress concentration. However, any shape other than a circle may be used depending on the purpose as long as the advantages of the hair for use in the present invention are utilized.

2. The diameter D of the toothbrush bristle 1 having a sea-island structure may be the same as that of a normal toothbrush bristle, and is preferably about 150 to 300 μm. The diameter d of the island fiber 3 is about 20 to 50 μm. If it is less than 20 μm, it is too thin, and there is a possibility that island fibers may be cut by stress during the cleaning. In addition, a large number of fibers must be arranged, which increases the difficulty of manufacturing and manufacturing the die of the coextrusion molding machine. On the other hand, when the diameter is larger than 50 μm, the ratio of the cross-sectional area of the island fiber 3 occupying the sea part 2 becomes too large due to the arrangement of a plurality of fibers, so that the brush durability is lowered and the advantage of the PTT hair may not be exhibited. is there.

3. Arrangement and shape of island fiber in hair cross section A plurality of island fibers 3 are arranged in the sea part 2, but preferably 3 or more, more preferably about 4 to 20 in range. The shortest distance m between the island fibers and the hair surfaces is 10 to 30 μm, preferably 10 to 20 μm. If it is shallower than 10 μm, the island fibers 3 may be exposed due to surface abrasion during use, and the arrangement may vary slightly due to manufacturing variations in the spinning process, which increases the risk of exposure of the island fibers 3. . If it is deeper than 30 μm, if scratches or tears occur on the surface layer, this may easily extend to the center of the hair.

  It is desirable that the plurality of island fibers 3 be arranged concentrically and at equal intervals in order to prevent crack extension evenly and to maintain uniform flexibility of the hair itself. The shortest distance n between the island fibers depends on the diameter d of the island fibers 3 and the diameter D of the toothbrush bristles 1 but is preferably in the range of 10 to 50 μm. If the shortest distance n between the island fibers is too narrow, the outer peripheral side is likely to be peeled off from the island fibers 3, and if it is too wide, the intended function tends not to be achieved.

  The cross-sectional shape of the island fiber 3 is basically preferably a circular shape, but may be a flat cross-sectional shape having long and short axes such as an ellipse. In the case of island fibers having long and short axes in the cross-sectional shape, as shown in FIGS. 3D and 3E, the direction of the long axis direction of the flat cross section is a tangential direction of a concentric circle c drawn around the hair shaft core. It is desirable to arrange them so that they almost coincide. Even in this case, the shortest distance n between the island fibers is in the range of 10 to 50 μm as described above. Arranging island fibers having a flat cross section in the vicinity of the surface layer has a great merit because the resistance to breakage of the PTT surface layer on the outer peripheral side can be maintained and the breakage resistance can be improved with a minimum volume of polyamide resin.

  Occupancy of island fiber 3 (ratio of total cross-sectional area of island fiber 3 to cross-sectional area of toothbrush bristle 1 occupancy = {total cross-sectional area of island fiber / cross-sectional area of toothbrush bristle} × 100 (%)) A range of about 10 to 45% is preferable. If the total cross-sectional area of the island fiber 3 is too small, it will be difficult to play a role of reinforcing the hair for sea-island structure, and if it is too large, the properties of the polyamide resin will be strong, and it will be difficult to exhibit high bending recovery as PTT hair. Become.

4). In the case of a flat-line type toothbrush, a plurality of toothbrush bristles 1 are bundled to form a hair bundle, which is a cut piece of about 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 a toothbrush head together with a flat line and driven. Then, a toothbrush is obtained by trimming a brush in arbitrary shapes and then carrying out a round-end finish. Even in a flat wireless type toothbrush such as an in-mold type toothbrush or a heat fusion type toothbrush, it is possible to plant hair by a method similar to the conventional manufacturing method.

According to the present invention, the following excellent effects can be achieved.
(1) By using PTT resin as the sea part, it is possible to obtain toothbrush bristle and toothbrush with high brush durability.
(2) Polyamide resin island fibers are arranged concentrically and equidistantly in the vicinity of the surface layer of the sea part made of PTT resin, which makes conventional PTT hair easy to tear and low chemical resistance. Is greatly improved.
(3) Due to the effective arrangement of the island fibers of the polyamide resin, there is no peeling of the surface layer as seen in the core sheath hair, and stable quality can be maintained even for long-term use.
(4) Since it can be produced only with a normal coextrusion molding machine, the hair for the present invention can be obtained easily and at low cost. In addition, since the hair can be planted by a conventionally known method regardless of whether it is a flat wire type or a flat wire-less type, the versatility is very high.

Embodiments of the present invention will be described below with reference to the drawings.
<First Embodiment>
FIG. 1 shows a first embodiment of a toothbrush bristle according to the present invention.
In the toothbrush bristle 1 according to the first embodiment, a PTT resin having a critical viscosity of 1.3 is used as the sea part 2, and nylon 610 is used as the island fiber 3, and six island fibers 3 are arranged concentrically. And made it an island.

  In order to obtain the toothbrush bristle 1, the fiber having the sea-island structure shown in the figure is melt-spun by a co-extrusion molding machine, extruded into water, cooled and solidified, and then in the first stage 60 ° C. warm water, the second stage 120. The film is stretched 4.5 times in a dry atmosphere at 0 ° C., and then a relaxation heat set is performed in a dry heat atmosphere and wound around a bobbin. As a result, the toothbrush bristle 1 having the bristle diameter D = 200 μm, the island fiber 3 diameter d = 50 μm, the shortest distance between the island fibers and the bristle surface m = 10 μm, and the shortest distance between the island fibers n = about 20 μm is obtained. it can.

  Further, the toothbrush bristles 1 are converged to a bundle diameter of 45 mm with a wrapping paper and cut into 30 mm cut pieces. After removing the wrapping paper from the cut piece, set it on the hair plate of the flat wire type hair transplanter (Zahoransky ZT-1TC). After that, the hair is implanted into a toothbrush head (planting hole φ1.5 mm, 8 rows × 3 columns) together with a flat wire. Next, the brush was trimmed to a bristle length = 10 mm and subjected to a rounded-end finishing process to obtain a toothbrush of the present invention.

(Cross-sectional shape of the toothbrush bristle in FIG. 1)
Diameter D of toothbrush bristle 1: 200 μm
Island fiber 3 diameter d: 50 μm
Shortest distance between island fiber and hair surface m: 10 μm
Shortest distance n between island fibers: 20 μm
Number of island fibers 3: 6 Occupancy of island fibers 3: 38%

<Second Embodiment>
FIG. 2 shows a second embodiment of the toothbrush bristle according to the present invention.
The toothbrush bristle 1 according to the second embodiment uses PTT having a critical viscosity of 1.3 as the sea part 2 and uses nylon 612 as the island fiber 3. This is an island part arranged.

  In order to obtain the toothbrush bristle 1, the fiber having the sea-island structure shown in the figure is melt-spun by a co-extrusion molding machine, extruded into water, cooled and solidified, and then in the first stage 60 ° C. warm water, the second stage 120. The film is stretched 4.5 times in a dry atmosphere at 0 ° C., and then a relaxation heat set is performed in a dry heat atmosphere and wound around a bobbin. As a result, it is possible to obtain a toothbrush bristle 1 having a bristle diameter D = 200 μm, an island fiber 3 diameter d = 30 μm, an island fiber-bristle surface shortest distance m = 10 μm, and an island fiber shortest distance n = 30 μm. It was.

  Further, the toothbrush bristles 1 are converged to a bundle diameter of 45 mm with a wrapping paper and cut into 30 mm cut pieces. After removing the wrapping paper from the cut piece, place it on the flat plate of the flat-line type flocking machine (Zahoransky ZT-1TC). Then, the hair is implanted into a toothbrush head (planting hole φ1.5 mm, 8 rows × 3 columns) together with a flat wire. Next, the brush was trimmed to a bristle length = 10 mm and subjected to a rounded-end finishing process to obtain a toothbrush of the present invention.

(Cross sectional shape of toothbrush bristle in FIG. 2)
Diameter D of toothbrush bristle 1: 200 μm
Island fiber 3 diameter d: 30 μm
Shortest distance between island fiber and hair surface m: 30 μm
Shortest distance n between island fibers: 10 μm
Number of island fibers 3: 8 Occupancy of island fibers 3: 18%

FIG. 3 shows another cross-sectional shape example of the toothbrush bristle according to the present invention.
(A) is an example in which four island fibers 3 having a circular cross section made of polyamide resin are concentrically arranged in the sea part 2 made of PTT resin, and (b) is a polyamide resin in the sea part 2 made of PTT resin. An example in which 12 island fibers 3 having a circular cross section are arranged concentrically, (c) is a cross section of two types of island fibers having different diameters made of polyamide resin in a sea part 2 made of PTT resin. 8 is an example in which 8 are arranged alternately in a concentric manner, and (d) is an example in which 6 island fibers 3 having an elliptical cross section made of polyamide resin are concentrically arranged in a sea part 2 made of PTT resin. (E) is an example in the case where eight island fibers 3 having an elliptical cross section made of polyamide resin and island fibers 3 having an elliptical cross section are alternately arranged in a concentric manner in a sea part 2 made of PTT resin. In the case of a toothbrush bristle using island fibers 3 having an elliptical cross section (FIGS. 3D and 3E), a concentric circle c in which the direction of the major axis direction of the elliptical cross section is drawn around the hair shaft core. It is desirable to arrange so that it substantially coincides with the tangential direction.

Next, the experimental result of the toothbrush bristle which concerns on this invention is shown.
1. Appropriate evaluation as toothbrush hair Comparative product 1 (PTT hair): Toothbrush hair made entirely of PTT resin with a limit viscosity of 0.8 Comparative product 2 (PTT hair): Whole made of PTT resin with a limit viscosity of 1.3 Toothbrush bristles Comparative product 3 (nylon bristles): Toothbrush bristles made entirely of nylon 612 Product 1 of the present invention: Sea part = PTT resin (limit viscosity = 1.3)
Island fiber = nylon 610 (diameter d = 50μm, 6)
Shortest distance between island fiber and hair surface m = 10 μm
Shortest distance between island fibers n = 20μm
Invention product 2: Sea part = PTT resin (limit viscosity = 1.3)
Island fiber = nylon 612 (diameter d = 30μm, 8)
Shortest distance between island fiber and hair surface m = 10 μm
Shortest distance between island fibers n = 30μm
In addition, all of the said comparative products 1-3 and this invention products 1 and 2 are the diameter D = 200 micrometers of toothbrush bristle.

Experimental method: Toothbrushes were prepared using the toothbrush bristles of Comparative products 1 to 3 and Invention products 1 and 2, respectively, and a reciprocating brush load with a model brush tester: 500 g
Stroke: 20mm
Speed: 150rpm / min
Number of brushes: 200,000 repetitions: n = 6
Evaluation method: Evaluation by visually observing the state of the toothbrush bristle after the brush test

As is apparent from the evaluation results in Table 1, the comparative products 1 and 2 made of PTT hair change the difficulty of breaking due to the limiting viscosity of the PTT resin, and the characteristics become unstable. Moreover, the comparative product 3 made of nylon hair has a problem in bending recovery. On the other hand, the products 1 and 2 of the present invention were able to achieve both the difficulty of breaking the hair and the bend recovery.

2. Changes in properties due to differences in the arrangement of island fibers-Sample hair: Hair diameter D = 200 µm
Sea part = PTT resin (limit viscosity = 1.3)
Island fiber = nylon 612 (diameter d = 20 μm)

  As is clear from the test results of Table 2, the shortest distance m between the island fibers and the hair surface is preferably around 20 μm. The shortest distance n between the island fibers is preferably around 30 μm.

3. Changes in properties due to differences in island fiber occupancy Sample hair: Diameter D = 200 μm
Sea part = PTT resin (limit viscosity = 1.3)
Island fiber = nylon 612
Shortest distance between island fiber and hair surface m = 10 μm

  As is clear from the test results in Table 3, it is preferable because the effect of improving the hair breakage is not sufficient when the island fiber occupancy is about 5% or less, and when it is about 50% or more, the characteristics of the PTT resin cannot be fully exhibited. Absent. Therefore, it is desirable that the island fiber occupancy be in the range of about 10 to 45%.

BRIEF DESCRIPTION OF THE DRAWINGS The 1st Embodiment of the toothbrush bristle which concerns on this invention is shown, (a) is an expanded sectional view, (b) is a partially cutaway perspective view. It is an expanded sectional view showing a 1st embodiment of hair for toothbrushes concerning the present invention. (A)-(e) is a figure which shows the other cross-sectional shape example of the toothbrush bristle which concerns on this invention.

Explanation of symbols

1 Toothbrush bristle 2 Sea part 3 Island fiber m Shortest distance between island fiber and bristle surface n Shortest distance between island fibers

Claims (5)

  A toothbrush bristle, characterized in that island fibers made of polyamide resin are arranged at substantially equal intervals along the outer periphery of the sea part in a sea part made of polytrimethylene terephthalate (PTT) resin.   The toothbrush bristle according to claim 1, wherein the shortest distance m between the island fibers and the bristle surface is 10 to 30 µm.   3. The toothbrush hair according to claim 2, wherein the shortest distance n between the island fibers is 10 to 50 [mu] m.   The toothbrush bristle according to any one of claims 1 to 3, wherein the island fiber has a circular or elliptical cross section, and the elliptical cross section of the island fiber is a major axis direction of the elliptical cross section. A toothbrush bristle characterized in that it is arranged so that the direction of the line substantially coincides with the tangential direction of a concentric circle drawn around the bristle shaft core.   A toothbrush comprising the toothbrush bristle according to any one of claims 1 to 4.

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