JP2010201197A - Toothbrush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothbrush which excels in fitness when holding a grip part and excels in slip prevention in any direction of the grip part. <P>SOLUTION: The toothbrush has a head part, a neck part, and the grip part. The grip part includes a core material part and a covering part which is made of a soft elastomer resin. The covering part covers 70% or more of the surface of the grip part. In the grip part, convex parts exposed on the surface of the covering part are formed respectively on a bristle plantation-surface side and a back surface side near a rear-end which is opposite to the neck part. Of these convex parts, the total area of the portion exposed outwardly is 10% and less of the area of the grip part, while forming a plurality of display projecting for visible logo-relief exposed on the surface of the core material part. The thickness of the covering part which encloses the display projections and covers the surface of the core material part is in the range of 2-5 mm. A friction coefficient of the surface of the covering part is equal to or more than 1. Surface-texturing is given to 50% or more of the covering part surface area. Rubber hardness of the covering part is 15-40. Roughness (Ra) of the surface-texturing is 10-200 μm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technology for improving a gripping portion of a toothbrush, and relates to a technology that is easy to grip and has a good fit property and a non-slip structure by using a special soft resin material such as a soft elastomer material for the gripping portion.

  Normally, the handle portion of the toothbrush is made of a hard thermoplastic resin, but there is a problem that it is slippery when gripped and has a low fit. For this reason, various types of toothbrushes have been proposed in which the gripping portion is covered with a soft material such as a thermoplastic elastomer so as to achieve both fit and grip resistance when gripped.

From such a background, as an example of a conventional toothbrush, an elongated cavity and a gripping element are formed on the back side of the handle gripping portion, and at least one flange for imparting rigidity is formed inside the gripping element, and the gripping element is thermoplastic. There is provided a toothbrush handle made of an elastic material and deformable by a finger. (See Patent Document 1)
As an example of another toothbrush, in the toothbrush handle made of hard material and soft material, the surface side of the handle is made of hard material, and the back and sides of the handle are made of soft material, and the hard material part does not hit the gum during brushing Thus, a toothbrush handle intended to prevent damaging the gums is provided. (See Patent Document 2)

As an example of other toothbrushes, a structure in which a hard shaft material and a soft exterior material are integrally formed by insert molding (see Patent Document 3), a soft synthetic resin on the outer periphery of a grip portion of a primary handle made of hard synthetic resin There is known a toothbrush handle (see Patent Document 4) having a structure in which an injection quality molding is performed and the entire peripheral surface of the grip portion is covered with a soft synthetic resin.
Moreover, as an example of another toothbrush, the handle portion is coated with a polyester thermoplastic elastomer having a rubber hardness in the range of 55 to 95 on both the width direction side surfaces of the handle base of the transparent saturated polyester resin and the handle gripping portion. There is known a toothbrush (see Patent Document 5) having a configuration and improved design and operability.

JP 2000-504609 Gazette Japanese Utility Model Publication No.59-123432 JP-A-2-71710 JP 2002-34659 A JP 2003-265232 A

In the toothbrush described in the above-mentioned patent document 1, although there is a soft feeling, an elastic material is provided only on the back side of the handle gripping portion, so that the fit and anti-slip properties when gripping the handle are insufficient. In particular, there was a problem of low fit and slip resistance when gripping the opposite side of the handle back side.
In the toothbrush described in Patent Document 2, the soft material provided on the back side and the side of the handle prevents the hard resin portion from hitting the gums during brushing and prevents the gums from being damaged. However, this soft material was not intended for handle fitting or slip prevention.

In the structure of the toothbrush described in Patent Document 3, a soft material is provided only on the back side of the gripping part, there is difficulty in fit when gripping the opposite surface on the back side of the handle, and slip resistance is low. There was a problem.
In the toothbrush structure described in Patent Document 4, the thickness of the soft synthetic resin is as thin as about 1 mm, which makes it difficult to fit, and there is room for further research on anti-slip properties.
In the structure of the toothbrush described in Patent Document 5, the rubber hardness is 55 to 95 and the fit is low because it is hard, and the anti-slip property is provided because the elastomer part is provided only on the side surface of the grip part. There was a drawback of being low.

  In general, in order to improve the usability in brushing of a toothbrush, it is important to use a handle-like gripping part that is excellent in fit and slip resistance. In view of this, the handle-shaped gripping portion is constituted by a hard material core material and a soft material coating material, and an elastomer resin is generally used as the soft material coating material. However, when the friction coefficient of the elastomer resin is low, and when the covering area of the gripping portion is not large, there is a problem that the slip prevention property of the gripping portion is not good. Furthermore, when the hardness of the elastomer resin is hard, and when the thickness of the covering material at the grip portion is thin, there is a problem that the fitting property as a toothbrush is not good.

  In order to solve the above problems, the present inventors have a toothbrush that has excellent fit when gripping the gripping part from any direction and is excellent in slip resistance in any direction of the gripping part. The purpose is to provide. Another object of the present invention is to provide a toothbrush that is excellent in fit, excellent in anti-slip properties, and that does not easily stain the covering portion.

In order to achieve the above object, the present invention employs the following configuration.
In the toothbrush of the present invention, the toothbrush has a head portion in which hair bundles are implanted, a neck portion, and a gripping portion, and the gripping portion is in contact with the core portion made of a thermoplastic resin. And a covering portion made of an elastomer resin that is softer than the core portion, and the covering portion covers 70% or more of the surface of the gripping portion, Forming a convex portion that protrudes outward from the core material portion and is exposed to the surface side of the covering portion on the flocked surface portion side and the back surface side in the vicinity of the rear end side opposite to the neck portion side in the gripping portion; The total area of the portions exposed to the outside from the covering portion in these convex portions is 10% or less of the area of the gripping portion, and the surface side of the covering portion via the covering portion on the surface side of the core member portion A plurality of display protrusions for logo relief that are exposed and visible are formed around the display protrusions. The covering portion covering the surface of the core portion and the thickness of the covering portion is in the range of 2 to 5 mm, the friction coefficient of the surface of the covering portion is set to 1 or more, and the surface area of the covering portion is 50% or more subjected to embossing. The rubber hardness of the covering portion is in the range of 15 to 40, and the roughness (Ra) of the embossing is in the range of 10 to 200 μm.

The toothbrush of the present invention is characterized in that the covering portion is formed from a styrene elastomer resin.
The toothbrush of the present invention is characterized in that the coefficient of friction of the surface of the covering portion is 2.0 or more.
The toothbrush of the present invention is characterized in that the covering portion covers 90% or more of the surface of the gripping portion.
The toothbrush of the present invention is characterized in that the thickness of the covering portion is in the range of 2 to 3 mm.

According to the present invention, since the covering portion of the soft resin material covers the peripheral surface of the core portion, it has a good grip property even when it is gripped from any direction, and the friction coefficient of the surface of the covering portion is 1. Since it was mentioned above, there exists an effect which can provide a toothbrush which is hard to slip when it grasps.
Next, according to the present invention, the core part can be formed from a thermoplastic resin so as to exhibit an appropriate rigidity when brushed as a whole, and the covering part is made of an elastomer resin so that it can be easily gripped, and the rubber hardness of the covering part The toothbrush having no stickiness and being less likely to get dirty, having excellent adhesion to the core part, good fit, and good antiskid properties can be provided. Moreover, since the thickness of the covering portion is set to a suitable range of 2 to 5 mm, it is possible to obtain an appropriate elasticity when grasping the gripping portion, and it is easy to grip, and the thickness of the covering portion is not excessively increased. An easy-to-hold toothbrush that does not become too thick can be provided.

According to the present invention, when the total area of the portions exposed from the covering portion of the convex portion provided in the core portion is 10% or less, the core portion can be sufficiently covered with the covering portion, so that the holding portion is held. In this case, as a result of sufficiently reducing the contact area between the core member and the hand, it is possible to obtain anti-slip properties and to be easily handled during brushing.
According to the present invention, it is possible to suppress a sticky feeling peculiar to the coating portion of the elastomer resin, to provide a toothbrush that is easy to grip and excellent in fitting feeling by applying 50% or more of the surface of the coating portion. effective.
According to the present invention, the covering portion made of the soft resin material tends to be displaced with respect to the core portion by providing the convex portions that are separated from the front surface side and the back surface side of the core portion and exposed on the surface of the covering portion. Also, since the convex portion suppresses this, the convex portion has an effect of preventing the cover portion from being soft. By providing a plurality of these convex portions in the length direction of the front and back surfaces of the core portion, it is possible to realize effective displacement prevention of the covering portion.
In the present invention, when the friction coefficient of the covering material is 2 or more, the toothbrush can be provided with a handle having a good anti-slip property.
In the present invention, by covering 90% or more of the handle gripping portion with a styrene-based elastomer resin, a toothbrush provided with a handle having a good anti-slip property can be obtained.
In the present invention, by setting the rubber hardness of the styrene-based elastomer resin to 15 to 40 and the thickness to 2 to 3 mm, the toothbrush having a handle that has no stickiness, is not easily soiled, does not easily peel off, and has excellent fit. Can provide.

FIG. 1 shows a basic form of a toothbrush, FIG. 1 (A) is a front view of the toothbrush, FIG. 1 (B) is a side view of the toothbrush, and FIG. 1 (C) is a cross-sectional view of the toothbrush. FIG. 1D is a back view of the toothbrush. FIG. 2 shows a part of the toothbrush. FIG. 2A is a front view of a part of the toothbrush, FIG. 2B is a side view of a part of the toothbrush, and FIG. A sectional view of a part of the toothbrush and FIG. 2D is a back view of a part of the toothbrush. FIG. 3 shows the toothbrush according to the first embodiment of the present invention. FIG. 3 (A) is a front view of the toothbrush, FIG. 3 (B) is a side view of the toothbrush, and FIG. 3 (C) is the toothbrush. FIG. 3D is a back view of the toothbrush. FIG. 4 shows a part of the toothbrush according to the first embodiment of the present invention. FIG. 4 (A) is a front view of a part of the toothbrush, and FIG. 4 (B) is a side view of a part of the toothbrush. 4C is a cross-sectional view of a part of the toothbrush, and FIG. 4D is a back view of a part of the toothbrush.

Hereinafter, a basic form will be described with reference to the drawings.
1 and 2 show a toothbrush according to a basic form, and a toothbrush A of this form has a head part 2 in which a hair bundle 1 is implanted, a neck part 3 and a grip part 4, The grip portion 4 includes a core material portion 5 made of a hard resin material, and a covering portion 6 made of a soft resin material that is in contact with the core material portion 5 and is applied to almost the entire circumference of the core material portion 5. The covering portion 6 covers 70% or more of the surface of the grip portion 4, and the friction coefficient of the surface of the covering portion 6 is 1 or more.
As shown in the side view of FIG. 1B and the cross-sectional view of FIG. 1C, the grip portion 4 is formed thicker in the thickness direction than the head portion 2 and the neck portion 3, and is shown in FIG. As shown in the plan view and the back view of FIG. 1D, the grip portion 4 is also formed thick in the width direction. This is because the covering portion 6 is attached around the core portion 5 in the grip portion 4.

In the toothbrush A of this form, the neck portion 3 is shaped so that the grip portion 4 side is slightly thicker than the head portion 2 side, and the core member portion 5 is a plan view of FIG. 2 (A) and FIG. 2 (D). As shown in the rear view of FIG. 2B, the lateral width of FIG. 2B is slightly larger than the narrowest portion of the neck portion 3 and slightly narrower than the thickest portion of the neck portion 3 in the width direction. ) In the thickness direction as shown in the cross-sectional view of FIG. 1 (C), the core portion 5 is formed to have the same thickness as that of the thick portion of the neck portion 3. As shown in FIG. 2, the curve is formed so as to be slightly convex upward and to be easily gripped.
Next, on the back side of the core part 5, an elliptical convex part 5 </ b> A as viewed from the back is formed at the front end side center which is a part close to the neck part 3, and the back end side center of the back side of the core part 5 A convex portion 5B having an elliptical shape when viewed from the back is formed. On the surface side of the core member 5, an elliptical convex portion 5C in plan view is formed on the center in the length direction, and on the surface side of the core member 5, the convex portion 5D in plan view on the rear end side. Is formed at a position corresponding to the convex portion 5B. A plurality of display protrusions 5E for displaying the product name (for logo relief) are formed on the surface side of the core member 5 between the protrusions 5C and 5D.

  Next, as shown in FIGS. 1A to 1D, the core material portion 5 is provided on the outer side of the core material portion 5 with an appropriate thickness on any of the four surrounding surfaces of the core material portion 5. A covering portion 6 made of a surrounding soft resin material is formed. The covering 6 is formed to a thickness that covers the peripheral surfaces of the protrusions 5A to 5D so as not to cover the upper surfaces of the protrusions 5A to 5D of the core member 5.

The head part 2, the neck part 3 and the core part 5 are integrally molded with a primary mold of a hard resin material such as a thermoplastic resin. For example, a polypropylene resin or a polyester resin can be used as the material. In view of strength, moldability and cost, polypropylene resin is most preferable.
The covering portion 6 is integrally molded on the outer peripheral portion of the core portion 5 with a secondary mold made of a soft resin material. Examples of the material include a styrene elastomer resin, an olefin elastomer resin, and a polyester elastomer resin. However, styrenic elastomer resins are most preferable from the viewpoints of flexibility, anti-slip properties, and adhesion to the core material.
Specific examples of the styrene-based elastomer resin include, for example, the product name “Thermolast” of Kleburg, Germany, the product name “Lavalon” of Mitsubishi Chemical Corporation, the product name “Septon” of Kuraray Co., Ltd., Riken Vinyl ( The product name “Reostomer” of Asahi Kasei Co., Ltd. and the product name “Tough Tech” of Asahi Kasei Co., Ltd. can be used.

In the toothbrush A, when the gripping part 4 serving as the handle part has a friction coefficient of the covering material 6 of 1 (friction coefficient against an aluminum or stainless steel metal plate according to JIS K7125) or more, more preferably 2 or more, anti-slip property is good. The handle portion can be made. Here, when the friction coefficient of the covering portion 6 is less than 1, sufficient anti-slip properties cannot be obtained during brushing using the toothbrush A.
By covering and forming 70% or more, more preferably 90% or more, of the surface area of the gripping portion 4 with the covering portion 6, the gripping portion 4 having good anti-slip properties can be obtained. Covering less than 70% of the surface area of the gripping portion 4 with the covering portion 6 is sufficient to prevent slipping during brushing because the contact area between the portion of the covering material 6 and the hand is small when the gripping portion 4 is gripped by hand. I can't get sex.
An organic or inorganic pigment may be added to the styrene-based elastomer resin coating 6 and may be appropriately colored and molded, or may be molded in a natural color not added. A toothbrush A having an aesthetic appearance in which the protrusion 5E can be seen translucently through the covering portion 6 can be obtained. Here, the thickness of the covering portion 6 covered on the surface of the display protrusion 5E makes it easy to visually recognize the logo of the display protrusion 5E such as characters when the inside display protrusion 5E is viewed with the naked eye. For this purpose, it is preferable to set the thickness of the covering portion 6 on the display projection 5E to about 0.5 to 2.0 mm. Here, if the thickness of the covering portion 6 is less than 0.5 mm, the resin does not enter the molding cavity (the gap between the mold surface and the display projection 5 of the primary molded product) when molding with a mold. In contrast, when the covering portion 6 on the display protrusion 5E has a thickness of 2 mm or more, the display protrusion 5E cannot be recognized from the outside, which is not preferable.

When molding the core part 5 (hard core part) of the toothbrush A having the above-described configuration, it can be molded using a general injection molding machine and a mold as a primary mold. In addition, when molding the styrene elastomer resin coating 6 with a secondary mold, it can be molded using a general injection molding machine, but the mold may use a hot runner valve gate system or a pin gate system. Among them, the hot runner / valve gate method is suitable.
In order to improve the slip prevention property, the gripping portion 4 of the toothbrush A may be provided with unevenness or ribs on the surface of the covering portion 6, or may be subjected to embossing on the surface. For the grip portion 4, a styrene elastomer resin having a rubber hardness of 15 to 40 of the covering portion 6 is suitable in terms of fit. Here, if the rubber hardness is less than 15, the stickiness of the hand is strong when the gripping part is gripped, and dirt is easily attached. On the other hand, if the rubber hardness is less than 15, the adhesiveness to the core material portion 5 is low, and it is easy to peel off from the core material portion 5, which is not suitable. When the rubber hardness is 40 or more, the covering portion 6 becomes hard when the grip portion is gripped, and a fit cannot be obtained. Moreover, it is not suitable because the anti-slip property is lowered.
In the grip part 4, it is suitable from the point of fit that the thickness of the covering part 6 is formed in the range of 2 to 5 mm. When the thickness is 2 mm or less, the covering portion 6 is felt hard when the grip portion 4 is gripped, and the fit feeling is low, which is not preferable. If the thickness of the covering portion 6 is 5 mm or more, the grip portion becomes too thick and is difficult to hold by hand.

In the toothbrush A, the convex portions 5A to 5D of the grip portion 4 are exposed at a total of four locations, and the exposed area of the core portion 5 is limited to 10% or less of the surface area of the grip portion 4. By doing so, a high slip prevention property of the grip portion 4 is obtained.
The convex portions 5B, 5C, and 5D of the core material are exposed at a total of three locations on the upper and lower surfaces in the vicinity of the rear end portion side of the grip portion 4 and the flocked surface side in the center of the grip portion, and the exposed area of the core material portion 5 is exposed. By restricting the surface area to 10% or less of the surface area of the grip portion 4, high slip prevention performance of the grip portion can be obtained.
In addition, when an elastomer resin having a high coefficient of friction is used as the constituent material of the covering portion 6, the anti-slip property is excellent, but it becomes easy to stick when the handle is gripped. The The embossing is desirably provided on the entire surface of the coating material or 50% or more of the surface of the coating material. If it is less than 50%, the anti-sticking effect by embossing is low. When the rubber hardness of the coating material is 15 to 40, from the viewpoint of stickiness and moldability, the roughness of the embossing process is preferably in the range of Ra = 10 to 200 [mu], and when Ra is less than 10 [mu], there is stickiness, and Ra = 200 [mu] or more. Then, moldability deteriorates.

  If it is toothbrush A comprised as mentioned above, it has moderate fitting property and slip prevention property, can be easily gripped, and can provide a good feeling of use. Further, it is possible to provide a toothbrush A that can suppress a sticky feeling peculiar to the coating portion 6 of the elastomer resin, is easy to grip, has a good fit, and can be handled well during brushing.

By the way, in the toothbrush A of this form, the bristles 1 use, for example, synthetic resin bristles as the bristles constituting the bristles, and the cross-sectional area of the synthetic resin bristles is for a circular cross section having a diameter of 0.102 mm (4 mi1) or less. It can be equivalent to the cross-sectional area of the hair. Further, the flock hole to be implanted with the hair bundle has a size corresponding to the hole cross-sectional area of a circular flock hole having a diameter of 1.8 mm or more, the flock hole density is 45% or more, and the hair filling rate is 70 to 95%. can do.
The hair to be planted in the previous planting hole is preferably a synthetic resin hair having a diameter of 0.152 mm (6 mi1) or less, and more preferably in the range of 0.102 to 0.127 mm (4 to 5 mi1). Further, the hair may be a combination of different diameters, for example, a 4 mil and a 5 mil hair may be combined.
If it is thicker than 0.127 mm (6 mi1), it does not tend to be unsuitable as a soft periodontal disease toothbrush, and the cleaning power for narrow gaps is reduced. When the hair bundle is composed of synthetic resin bristles with a diameter of 0.127 mm (5 mi1) or less, it is soft and comfortable to touch, and exhibits high cavern removal ability to every corner of the oral cavity even with weak printing pressure. Will be able to.
The hair material can be any synthetic resin conventionally used for toothbrushes, such as polyamide such as nylon, polybutylene terephthalate, polyethylene terephthalate, polyester such as polytrimethylene terephthalate, or polypropylene. . Those blended resins may be used. In order to reduce the cost, synthetic resin hair such as nylon may be employed, and each hair bundle may be composed of single diameter hair.

3 and 4 show a first embodiment of the toothbrush according to the present invention, and the toothbrush B of this embodiment has a head portion 2 in which the bristle bundle 1 is implanted, a neck portion 3, and a grip portion 4. The grip portion 4 includes a core material portion 5 made of a hard resin material, and a covering portion 6 made of a soft resin material that is in contact with the core material portion 5 and is applied to almost the entire circumference of the core material portion 5. The basic structure that the covering portion 6 covers 70% or more of the surface of the gripping portion 4 and the friction coefficient of the surface of the covering portion 6 is 1 or more is described above. It is set as the structure equivalent to the toothbrush A of a form.
The toothbrush B of the first embodiment has basically the same structure as the toothbrush A of the first embodiment except that the convex portions 5A and 5C provided in the toothbrush A are omitted. In the structure of the first embodiment, the portions where the protrusions 5A and 5C are formed are covered with a styrene elastomer resin coating 6 as shown in FIG. A slightly tall display projection 5E ₂ for displaying a product name is also formed in the portion where the plurality of display projections 5E for name display (for logo relief) are formed, and the tip of the display projection 5E ₂ The difference is that the portion is exposed to the surface side of the covering portion 6 of the styrene elastomer resin and is easily visible.
Since the other configuration of the toothbrush B of the second embodiment is the same as that of the toothbrush A of the previous form, the same effect as that of the toothbrush A of the previous form can be obtained.

“Test Example 1”
The primary mold is formed by injecting polypropylene resin into the primary mold to form a primary molded body composed of the head portion configured as shown in FIG. 2, the neck portion, and the core material portion of the gripping portion continuous thereto, and then into the secondary die. A primary molded body molded with a primary mold was loaded, and a covering material made of a styrenic elastomer resin was molded and integrated on the outer peripheral side of the core portion of the primary molded body to produce a two-color molded toothbrush. . Further, after integration, a synthetic resin filament was planted in the head portion of the handle portion to obtain a toothbrush.
When producing a toothbrush based on this process, 20 rubber hardnesses of styrene-based elastomer resin are used, the thickness of each of them is 3 mm, and the friction coefficient of the surface is 0.5, 1.0, 2.0. Various types of toothbrush samples were manufactured by setting three types and three types of surface areas of 50%, 70%, and 90%, and each sample was tested for fit when actually grasped by hand. The results are shown in Table 1 below.
The experimental conditions in Table 1 are: how to hold: palm grip, evaluation method: sensory evaluation, evaluation criteria: ◎: the handle is very slippery when brushing, ○: the handle is difficult to slip when brushing, Δ : Evaluation was made based on the criteria that the handle was slightly slippery during brushing, x mark: the handle was slippery when brushing.

From the results shown in Table 1, the friction coefficient of the covering material of the gripping part which becomes the handle part is 1 or more (a value corresponding to the friction coefficient 1 for an aluminum or stainless steel metal plate according to JIS K7125), more preferably 2 or more. It can be seen that the handle has a good anti-slip property. Further, it was found that when the friction coefficient is less than 1, sufficient anti-slip property cannot be obtained during brushing.
Furthermore, it was found that 70% or more, more preferably 90% or more, of the surface area of the handle gripping part is formed by coating with a styrene elastomer resin to provide a gripping part with good anti-slip properties. In addition, when the covering ratio is less than 70% of the surface area of the gripping part, when the gripping part is gripped, the contact area between the covering material part and the hand is small.
From these test results, it was found that 70% or more of the surface area of the gripping part needs to be coated with a coating material of styrene-based elastomer resin, and the coefficient of friction is preferably 1.0 or more. .

"Test Example 2"
Next, the structure of 90% coverage used in the previous test example 1 is adopted, the rubber hardness of the styrene-based elastomer resin is set to three types of 15, 40, and 60, and the thickness is set to three types of 1, 2, and 3 mm. Toothbrush samples were prepared and tested for fit when each sample was actually gripped. The results are shown in Table 2 below.
The experimental conditions in Table 2 are: Holding method: Palm grip, Evaluation method: Sensory evaluation: Evaluation criteria: ◎ mark: Handle gripping part fits the hand very much, ○ mark: Handle gripping part fits the hand, △ mark : Evaluation was made based on the criteria that the handle gripping part does not fit the hand very much, x mark: the handle gripping part does not fit the hand at all.

From the results shown in Table 2, when the gripping part as the handle part is gripping the gripping part, a styrene-based elastomer resin having a rubber hardness of 15 to 40 is suitable in terms of fit, and when the rubber hardness is less than 15, Strong hand stickiness, easy to get dirty, rubber hardness less than 15 is not suitable because it has low adhesion to core material and easily peels off, and when rubber hardness is 40 or more, it covers when gripping the grip It was found that the material is hard and a fit cannot be obtained, and that the anti-slip property is also low, which is not suitable.
Moreover, it turned out that it is suitable from the point of fit property to shape | mold the grip part as a handle | steering-piece with the thickness of a coating | covering material 2-5 mm. That is, it was found that when the thickness is 2 mm or less, the covering material is hard and has a low fit when gripping the grip portion, and when the thickness is 5 mm or more, the grip portion becomes too thick and difficult to hold.
From these test results, it was found that the rubber hardness is in the range of 15 to 40 and the thickness is in the range of 2 to 5 mm for the toothbrush.

“Test Example 3”
In a toothbrush handle having a head portion, a neck portion, and a gripping portion according to the present invention, the gripping portion is composed of a hard material core material and a soft material coating material, the core material is formed from polypropylene resin, and the friction of the coating material The coefficient of friction is 2 and the friction coefficient of the coating material is a toothbrush in which the coating material is formed from a styrene elastomer resin with a rubber hardness of 20 and about 90% of the gripping part surface is coated with an average thickness = 3 mm with the above styrene elastomer resin. 0.2, a toothbrush having a structure in which an olefin-based elastomer resin having a rubber hardness of 60 is used as a covering material and about 90% of the gripping part surface is covered with an average thickness = 1 mm (Comparative product: Japanese Patent Laid-Open No. 2000-265232) A use test was carried out with the toothbrush equivalent) described. The results are shown in Table 3 below.
In Table 3 below, the number of panels (number of tests): n = 30, test period: 2 weeks, 7-level absolute evaluation (very good: 7 points, good: 6 points, somewhat good: 5 points, neither can be said. : 4 points, slightly bad: 3 points, quite bad: 2 points, very bad: 1 point).

  As a result of the use test shown in Table 3, it was confirmed that the product of the present invention is a toothbrush having a higher anti-slip property, a significantly improved fit, and an excellent usability than the comparative product.

“Test Example 4”
Next, in the styrene elastomer resin constituting the covering portion, when an elastomer having a high friction coefficient is used, the slipperiness is excellent, but the stickiness as a touch transmitted to the hand when the grip portion is gripped becomes a problem. Therefore, in order to perform this stickiness test, a stickiness evaluation test was performed based on the presence or absence of embossing formed on the surface of the styrene elastomer resin.
The evaluation test uses a styrene-based elastomer resin having a rubber hardness of 15, 40 and a friction coefficient of 1.0, an average thickness of 3 mm, and an average roughness (Ra) of the texture formed on the surface of less than 10 μm. A sticky state and moldability were individually evaluated for a sample having a range of 200 μm and a sample having a size exceeding 200 μm. The results are shown in Table 4 below.
In Table 4 below, a sample with a sticky circle is a sample that does not feel sticky when the gripping part is gripped, a sample with a × mark is a sample that feels sticky, and a circle in the moldability is a sample that can be molded without problems. A cross indicates a sample in which moldability is hindered in terms of releasability from the mold.

  From the results shown in Table 4, when the rubber hardness of the coating material made of styrene-based elastomer resin is 15 to 40, the roughening roughness is preferably in the range of Ra = 10 to 200 µ in terms of stickiness and moldability. When Ra = 10 μm or less, there was stickiness, and when Ra = 200 μm or more, the moldability was poor. Further, it is desirable that the above embossing is provided on the entire surface of the covering material or 50% or more of the covering material surface. If it is less than 50%, the anti-sticking effect due to embossing is reduced. Accordingly, rubber having a rubber hardness of 15 to 40 and having a grain roughness in the range of 10 to 200 μm has no stickiness and good results in moldability.

  A ... toothbrush, 1 ... hair bundle, 2 ... head part, 3 ... neck part, 4 ... grip part (handle part), 5 ... core material part, 5A, 5B, 5C, 5D ... convex part, 6 ... covering part.

Claims (5)

A head portion having a hair bundle implanted therein, a neck portion, and a gripping portion, the gripping portion contacting a core material portion made of a thermoplastic resin, and covering the peripheral surface of the core material portion. And a covering portion made of an elastomer resin that is softer than the core material portion, and the covering portion covers 70% or more of the surface of the gripping portion,
In the grip portion, convex portions that protrude outward from the core member portion and are exposed to the surface side of the covering portion are individually formed on the flocked surface portion side and the back surface side near the rear end side opposite to the neck portion side. The total area of the portions exposed to the outside from the covering portion in these convex portions is 10% or less of the area of the grip portion,
A plurality of display protrusions for logo relief that are exposed on the surface side of the covering portion and visible through the covering portion are formed on the surface side of the core portion, and surround the display protrusions and surround the core. The thickness of the covering portion covering the surface of the material portion is in the range of 2 to 5 mm,
The surface friction coefficient of the covering portion is set to 1 or more, 50% or more of the surface area of the covering portion is textured, and the rubber hardness of the covering portion is in the range of 15 to 40, the roughness of the textured surface (Ra ) In the range of 10 to 200 μm.   The toothbrush according to claim 1, wherein the covering portion is formed from a styrene elastomer resin.   The toothbrush according to claim 1 or 2, wherein a friction coefficient of the surface of the covering portion is 2.0 or more.   The toothbrush according to any one of claims 1 to 3, wherein the covering portion covers 90% or more of the surface of the grip portion.   The thickness of the said coating | coated part was made into the range of 2-3 mm, The toothbrush of any one of Claims 1-4 characterized by the above-mentioned.

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