JP2000014448A - Toothbrush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toothbrush excellent in various physical characteristics as a toothbrush such as a strength against comming-off of brushes and the bundles, napped conditions, durability, etc., moldability, and external appearance characteristics. SOLUTION: In a toothbrush prepared by implanting by means of a thermal bond method or an in-mold method at a specified position of a head 1 after the basal part of bundled brushes 2 has been molten by heating or the like to form a molten enlarged part 3. The embedding depth of the bundled brushes 2 is adjusted so that a ratio B/A of a distance B from the bottom face of the molten enlarged part 3 of the bundled brushes to the underface 5 of the head 1 right under the enlarged part to the thickness A from the upper face 4 of the head 1 on which the bundle of brushes 2 are implanted to the underface 5 is within 0.20-0.65. Further, a concrete depth of the distance B is defined within 0.5-2.6 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toothbrush, and more particularly, to a toothbrush manufactured by a heat sealing method or an in-mold method.

[0002]

2. Description of the Related Art Toothbrush manufacturing methods include, in addition to the conventional flocking method using a flat wire, Japanese Patent Publication No. 6-1672.
5, JP-A-61-268208, JP-A-2-111
No. 305, Japanese Patent Publication No. 6-469
The heat fusion method described in No. 62 is used, and the bundled bristles are adjusted to a predetermined denseness, a bunch shape, and a bristle shape, and the base end opposite to the bristles is heated. It is known that a hair bundle fused by means is implanted into a head portion by using an in-mold method or a heat fusion method.

[0003] Japanese Patent Application Laid-Open No. 61-268208 discloses that in the in-mold method, a molten enlarged portion of a hair bundle protruding into a mold cavity is brought into close contact with an opening of a mold hair bundle holding hole before injection molding. To prevent the injection resin from entering the hair bundle holding hole.

Japanese Patent Application Laid-Open No. 9-512724 discloses that in the in-mold method, the distance between the enlarged portion of the hair bundle protruding into the mold cavity and the opening of the mold hair bundle holding hole is determined by injection molding. Exhaust air from the cavity and gas generated from the injection resin are discharged, and the length region thermally weakened when the brush is melted is surrounded by the injection resin, and the injection resin does not enter the hair bundle holding hole. As such, adjusting is disclosed.

On the other hand, with respect to a handle for flat wire flocking, Japanese Patent Application Laid-Open No. HEI 8-19423 prevents warping and cracking of a head due to heat shrinkage balance in a molding process and deformation due to flat wire driving in a flocking process. Therefore, it is disclosed that the thickness between the bottom of the flocking hole and the lower surface of the head portion is defined.

[0006]

SUMMARY OF THE INVENTION Japanese Patent Application Laid-Open No. Sho 61-2682
In the method of No. 08, there is a molten enlarged portion immediately below the flocking surface of the completed toothbrush and the distance from the surface is short, so that the pull-out strength (stripping strength) of the bristle or brush cannot be satisfied, The direction of the brush was not perpendicular to the flocked surface (the hair bundle was opened), and the opening (durability) of the brush against the use of the brush was not always satisfactory.

In the method disclosed in Japanese Patent Application Laid-Open No. 9-512724, it is stated that the bristle portion, which has been thermally weakened during the formation of the molten enlarged portion, is buried in the brush head portion, thereby improving the hair removal strength. However, the application also describes that the brush should be buried as little as possible, that is, buried as shallow as possible, and the depth from the flocked surface is not sufficient,
In practice, sufficient hair removal strength cannot be obtained.

Japanese Patent Application Laid-Open No. H8-19423 is a technique using a flat wire method and cannot be applied to a heat fusion method or an in-mold method. Conversely, according to the disclosed technology (specified numerical values), there is a possibility that problems may occur in the physical characteristics, moldability, and appearance of the toothbrush.

The present invention solves the above-mentioned problems, and provides a toothbrush which is excellent in various physical properties as a toothbrush such as hair removal strength, bristle, durability and the like of a bristle bundle and a brush, moldability and appearance characteristics. The purpose is to provide.

[0010]

According to a first aspect of the present invention, there is provided a toothbrush according to the first aspect, wherein a base end portion of a bundle of brushes is fused by heat or the like to form a molten enlarged portion. In a toothbrush manufactured by implanting a hair at a predetermined position of a head portion by a heat fusion method or an in-mold method, the thickness of the hair bundle with respect to the thickness (A) from the upper surface to the lower surface of the head portion where the hair bundle is implanted. Ratio (B) of distance (B) from the bottom surface of the molten enlarged portion to the lower surface of the head portion immediately below the enlarged portion
/ A) has a hair bundle of 0.20 to 0.65.

The toothbrush according to claim 2 is the toothbrush according to claim 1, wherein the distance (B) is:
It is set to be 0.5 to 2.6 mm.

[0012]

[Function] After the base end of the hair bundle is melted by means of heat or the like to form a molten enlarged portion, the head portion is planted with hair to produce a toothbrush. In order to make a toothbrush with excellent durability, it is naturally important that the brush itself has excellent physical properties, but the manner in which the bristle bundle is planted is also important.

In other words, if the hair implantation is shallow, the head resin portion holding the hair bundle is small, so that various stresses associated with the use are directly transmitted to the melt-enlarged portion at the base end of the embedded hair bundle. I will. For this reason, a toothbrush with insufficient characteristics and insufficient quality is obtained.

Conversely, if the hair implantation is deep, the above-mentioned properties are satisfied, but an extra brush material is required, and the cost becomes relatively high. Also, if the hair is deeply implanted, it is difficult for the heat fusion method to bond the head portion and the hair bundle deeply while maintaining a predetermined angle in a molten state. In some cases, the distance to the head is insufficient and the head itself may be deformed.

[0015] In the in-mold method, the hair bundle and the molten enlarged portion that protrude greatly into the mold cavity are deformed by the flow and pressure of the injection resin at the time of molding the head portion, or the flocking angle of the hair bundle is increased. Are deviated from a predetermined angle, or the injection resin enters the hair bundle holding hole of the mold, and so-called burrs are easily generated.

Further, when molding at a lower speed and / or lower pressure than usual in order to avoid such a problem associated with resin injection, the hair bundle and the molten enlarged portion protruding into the mold may cause resistance to resin flow. And the occurrence of weld lines around the hair bundles, short shots at the melt enlargement,
There is also a problem that the molten enlarged portion is likely to be exposed on the head surface.

In order to satisfy various physical characteristics as a toothbrush, the present invention relates to a method of measuring the thickness (A) from the upper surface to the lower surface of a head portion on which a bristle bundle is implanted, from the bottom surface of the fused enlarged portion of the bristle bundle. The ratio (B / A) of the distance (B) to the lower surface of the head portion immediately below the enlarged portion is 0.20 to 0.65.
By adjusting the burial depth of the hair bundle so that the distance (B) is set to 0.5 to 2.6 mm, the above-mentioned physical properties and moldability, hairiness, burr and the like are obtained. This makes it possible to achieve both of the appearance characteristics.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view of a toothbrush head for explaining the present invention. In the figure, 1 is a head portion, 2 is a hair bundle embedded in the head portion 1, 3 is a molten enlarged portion formed at a base end portion of the hair bundle, 4 is an upper surface of the head portion 1, and 5 is a head portion 1. It is the lower surface of. In the toothbrush of the present invention, the head portion 1 on which the bristle bundle 2 is planted is provided.
Hair bundle 2 with respect to thickness A from upper surface 4 to lower surface 5
Head 1 directly below the enlarged portion from the bottom of the enlarged portion 3
Of the distance B to the lower surface 5 is 0.20-0.
The embedding depth of the hair bundle 2 is adjusted so as to be 65. The distance B is preferably 0.5 to 2.6 mm in a general toothbrush.

As a material for the brush, commonly used polyamides (eg, 6-12 nylon, 6-10 nylon, 12 nylon, etc.), polyesters (eg, polybutylene terephthalate, polyethylene terephthalate, etc.), polypropylene and the like can be used. Can be used. Of course, a composite filament combining these may be used. Also, the cross-sectional shape of the brush is mainly circular, but is not particularly limited. For example, a brush having a polygonal cross section such as a square or a hexagon can be used.

The brush thickness is 3 to 10 mil (0.076
０．２0.245 mm), preferably 5-8 mil (0.1
27 to 0.203 mm) is good for general toothbrushes.
Normally, the diameter is the same in one brush except for the rounded part of the bristle tip. However, even in the case of the above-mentioned brush thickness near the root of the bristle bundle, the diameter gradually decreases toward the tip of the bristle. It may be in the form of highly tapered bristles.

The material of the toothbrush handle including the flocked portion may be a thermoplastic resin. For example, polypropylene, polyethylene, polyester, cellulose propionate, polyamide, polymethyl methacrylate, ABS and the like can be used. Are physical properties,
It is preferable in terms of price and the like as a whole. It is also preferable to form a multicolor molded handle in which these resins are combined with each other or with a thermoplastic elastomer.

In the actual manufacture of the toothbrush,
For example, as disclosed in JP-A-10-52317, when the base end of the hair bundle is melted with a hot plate, the height of the melted bottom may be uneven. In addition, the thickness of the head portion is tapered in the long axis direction of the brush (the direction from the head tip to the neck portion), a step is provided, and the lower surface of the head is curved in the short axis direction of the brush (transverse direction of the head). In some cases, a step is provided on the flocking surface. further,
A convex ridge may be provided on the lower surface of the head as disclosed in JP-A-6-54717.

In these cases as well, it is desirable that all the tufts implanted in the head part satisfy the requirements of the present invention, but this is not essential, and some of the tufts may be used for characterizing the toothbrush. The hair bundles may deviate from the requirements of the present invention to such an extent that the above-mentioned properties are not significantly deteriorated. In such a case, it is important for the appearance of the toothbrush, and the side surface of the bristle bundle is exposed, and there is a high probability of contact with the tooth surface when brushing the teeth. Alternatively, it is desirable that the hair bundles at the outer peripheral portion (the front end and the left and right ends) satisfy the requirements of the present invention described above.

[0024]

EXAMPLE As an example, 8 mil of 6-12 nylon is used.
A bundle of 36 hairs (0.203 mm) in diameter is formed into a circular hair bundle 2, and the base end of the hair bundle 2 is melted by heat to form a molten enlarged portion 3. Thickness A is 3.5mm
Thus, for a toothbrush planted in a very common hair bundle arrangement (2 + 3 × 7 = 23 bundles) by an in-mold method using a polypropylene resin, the distance from the bottom surface of the molten enlarged portion 3 to the lower surface 5 of the head portion 1 is set. When the distance B is changed,
Table 1 shows the measurement results of each characteristic. The molding was performed under the condition that no burr was formed on the flocked surface of the head portion 1.

[0025]

[Table 1]

As is evident from Table 1, the toothbrushes satisfying the requirements of the present invention (samples Nos. 2 and 3) were good in hairiness, flock strength and appearance.

[0027]

As described above, according to the first aspect of the present invention, the thickness from the upper surface to the lower surface of the head portion on which the hair bundle is planted (A) is enlarged from the bottom of the fused enlarged portion of the hair bundle. The ratio (B / A) of the distance (B) to the lower surface of the head portion directly below the head portion has a hair bundle of 0.20 to 0.65, and the invention according to claim 2 further comprises: By setting (B) to be 0.5 to 2.6 mm, a toothbrush excellent in various physical properties as a toothbrush such as hair removal strength, bristles, durability, and the like of a bristle bundle and a brush, and excellent moldability. In addition, poor appearance of the toothbrush such as hairs and burrs can be reduced, and productivity can be improved. Further, since the head portion can be made thinner while maintaining various physical characteristics of the toothbrush, a toothbrush having good operability in the oral cavity can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a toothbrush head for explaining the present invention.

[Explanation of symbols]

 Reference Signs List 1 head part 2 hair bundle 3 molten enlarged part 4 upper surface of head part 5 lower surface of head part A thickness from upper surface to lower surface of head part B distance from bottom surface of molten enlarged part to lower surface of head part

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Takao Kato 1-37 Honjo, Sumida-ku, Tokyo F-term in Lion Corporation (reference) 3B202 AA06 AB10 EG03

Claims (2)

[Claims] 1. A method according to claim 1, further comprising: fusing a base end portion of the bundle of the brushes with heat or the like to form a molten enlarged portion by heat or the like, and then implanting the hair at a predetermined position of the head portion by a heat fusion method or an in-mold method. In the toothbrush manufactured by the above method, the distance (B) from the bottom surface of the melted enlarged portion of the hair bundle to the lower surface of the head portion immediately below the enlarged portion with respect to the thickness (A) from the upper surface to the lower surface of the head portion where the hair bundle is planted. Ratio (B /
A) The toothbrush, wherein A) has a hair bundle of 0.20 to 0.65. 2. The distance (B) is 0.5 to 2.6 mm.
The toothbrush according to claim 1, wherein