JP2000014449A - Toothbrush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toothbrush having an excellent external appearance by a method wherein the strength of bundled bristles or bristles of brush, which is important as the quality of toothbrushes made by a thermal bonding or in mold method, can be sufficiently ensured and protrusions of injected resin extending to the outer peripheries of bundled bristles, so-called fins, can be avoided from being generated. SOLUTION: In a toothbrush wherein the proximal ends of bundled bristles 1, wherein bristles 2 are bundled, is melted by heat or the like to form a melted swollen part 3, which part 3 is then embedded in a bristle filling surface 5 of a head part 4, the cross-sectional area of the swollen part 3 is made 1.2-6 or preferably 1.5-4 times as large as the total sum of sectional areas of bristles 2. And a projection dimension L from the outer periphery of the bundled bristles 1 to the end of the outer edge of the part 3 is set to 0.05-3.0 mm or preferably 0.1-1.5 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toothbrush which is embedded in a flocked surface of a head portion after a base portion of a bundle of brushes is melted by heat or the like to form a molten enlarged portion.

[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
No. 62, Japanese Unexamined Patent Publication No. 2-99002, the bundle of hair bundles is adjusted to a predetermined density and the shape of the bundle of hairs, and the opposite side of the hair tips is heated or the like. It is known that the hairs integrated by the above are implanted into the head portion by an in-mold method or a heat fusion method.

[0003] Further, the base end of the hair bundle is melted by thermal means,
The point of forming a molten enlarged part is also disclosed in the above publication. However, in each of the publications, only a vaguely described side view depicting the molten enlarged part larger than the hair bundle is described, and a specific cross-sectional area that can sufficiently satisfy the quality as a toothbrush, No description has been given on the size from the outer periphery of the bristle bundle to the outer peripheral edge of the molten enlarged part.

[0004] The magnification of the cross-sectional area of the bloated portion relative to the total cross-sectional area of the brushes constituting the bristle bundle, or the overhang dimension from the outer periphery of the bristle bundle to the outer peripheral end of the bloated portion, the bristle planting strength (the bristle bundle and the brush There is a correlation between the toothbrush and the force at the time of pulling out from the resin), and a toothbrush having a smaller magnification or overhang dimension does not sufficiently melt the end of the bristle bundle by thermal means. With a toothbrush, the hair bundles and brushes fall off in the mouth during actual brushing, giving the user a great deal of discomfort, such as swallowing the hair bundles and brushes,
Further, there is a possibility that the toothbrush does not have a satisfactory cleaning function.

On the other hand, if the above-mentioned magnification or overhang is too large, in the case of the in-mold method, in the specification of a toothbrush of a general size, the molten enlarged portions of adjacent bristle bundles are connected to each other, and the mold cavity is closed. When the molten resin for molding the head portion is injected into the mold, the flow of the molten resin is hindered, which causes a so-called short shot in which the molten resin is not filled in the entire mold cavity.

Further, in order to improve the short shot, if factors that affect the flow of the resin, such as the injection pressure, are controlled to force the resin to flow easily,
The molten resin for molding the head portion enters the gap between the hair bundle holding hole of the mold and the hair bundle held therein, causing a problem that burrs are generated around the hair bundle, and the head portion and the handle portion are ejected. There is a problem that molding is difficult.

Further, in the case of the in-mold method, if the magnification or the overhang is too large, the molten enlarged portion at the base end of the bristle bundle comes into contact with the side wall surface in the toothbrush head molding die cavity, and the molten enlarged portion is formed. There is also a problem that the portion is exposed from the head side surface after molding. Excessive exposure of the molten enlarged portion results in a reduction in the amount of resin for molding the head portion, lowering the strength of the head portion against brushing pressure, and leading to problems such as breakage of the planted portion during brushing.

[0008] By increasing the dimension (edge width) between the hair bundle located at the outermost periphery of the flocking portion and the outer peripheral edge of the head portion,
Although the short shot and the exposure of the molten enlarged part from the head part side surface can be prevented, if this dimension (edge width) is increased, the head part becomes large as a result, and the operation performance and use performance in the oral cavity are reduced. A problem such as a low toothbrush occurs.

[0009] Further, if an excessively large molten enlarged part is produced, it takes a long time to melt, or a kogation is generated due to carbonization of the brush material, which impairs the appearance as a toothbrush.
The problem of sticky odor is caused.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and has a hair bundle which is important as a quality of a toothbrush manufactured by a heat fusion method or an in-mold method. An object of the present invention is to provide a toothbrush excellent in appearance quality, while ensuring sufficient bristle planting strength, preventing short shots of a handle resin and protrusion of an injection resin to the periphery of a bristle bundle, so-called burrs.

[0011]

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 the toothbrush buried in the flocked surface of the head portion, the cross-sectional area of the molten enlarged portion is 1.2 to 6 times larger than the sum of the cross-sectional areas of the brushes constituting the bristle bundle. It is more preferable that the magnification is 1.5 to 4 times.

A toothbrush according to a third aspect of the present invention is a toothbrush embedded in a flocked surface of a head portion after a base end portion of a bristle bundle of a brush is melted by means of heat or the like to form a molten enlarged portion. The overhang dimension from the outer periphery of the hair bundle to the outer peripheral end of the molten enlarged part is 0.05 to 3.0 mm. It is more preferable that the overhang dimension be 0.1 to 1.5 mm.

When the magnification and the overhang are set as described above, a sufficient flocking strength can be secured, and a satisfactory toothbrush can be manufactured in terms of appearance quality.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show one embodiment of the present invention. 1 (a) is a side view of the hair bundle and the molten enlarged part, FIG. 1 (b) is a plan view thereof, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1 (a), and FIG. It is a BB line sectional view in the inside.

In the drawing, 1 is a bristle bundle, 2 is a brush constituting the bristle bundle, 3 is a molten enlarged part formed by melting the base end of the bristle bundle 1 by thermal means, and 4 is a toothbrush head. The part 5 is a flocking surface.

In the toothbrush according to the present invention, the cross-sectional area of the molten enlarged portion 3 formed at the base end of the bristle bundle 1 is 1.2 to 1.2 times larger than the sum of the cross-sectional areas of the brushes 2 constituting the bristle bundle 1. 6 times,
More preferably, a toothbrush is manufactured using a hair bundle of 1.5 to 4 times, or the overhang dimension L from the outer periphery of the hair bundle 1 to the outer peripheral end of the molten enlarged part 3 is 0.05 to 3.
A toothbrush was produced using a bristle bundle of 0 mm, more preferably 0.1 to 1.5 mm. In addition, in order to manufacture the toothbrush of the present invention using the bristle bundle having such a magnification and an overhang dimension, a known heat fusion method or an in-mold method may be used.

The burying depth D of the molten enlarged portion 3 buried in the flocking surface 5 of the head portion 4 can be set according to the thickness of the head portion 4 and is not particularly limited. It is preferable that the interface between the molten enlarged part 3 and the non-melted part of the hair bundle 1 is located at a distance from the flocked surface 5, and it is usually desirable to keep a distance of about D = 0.5 to 1.5 mm.

As a thermal means for integrating the base end of the hair bundle 1 in which a plurality of brushes 2 are bundled, hot air, warm air, a hot plate, a laser, an ultrasonic wave, an infrared ray or the like can be used.

Further, the molten enlarged portion 3 formed at the base end of the hair bundle
In order to control the shape and size of the hair bundle, the base end of the hair bundle may be melted by thermal means, and then a plate or the like may be pressed against the melted portion to form the hair bundle. Further, when a hot plate is used, a concave portion is provided in advance on the surface of the hot plate, and the concave portion is pressed against the base end of the bristle bundle, so that it can be shaped into a desired shape simultaneously with melting. .

Examples of the material of the brush 2 include commonly used polyamides (eg, 6-12 nylon, 6-10 nylon, 12 nylon, etc.), polyesters (eg, polybutylene terephthalate, polyethylene terephthalate, etc.), polypropylene, etc. Can be used. Of course, a composite material combining these may be used. The cross-sectional shape of the brush 2 is usually mainly circular, but is not particularly limited. For example, a brush having a polygonal cross-sectional shape such as a square or a hexagon can be used.

The brush thickness is 3 to 10 mil (0.076
０．２0.254 mm), preferably 5 to 8 mil (0.1
27 to 0.203 mm) is good for general toothbrushes.
Normally, the thickness is the same in one brush except for the rounded portion of the bristle tip. However, even in the vicinity of the root of the bristle bundle, even with the above-mentioned brush thickness, the diameter gradually increases toward the tip of the bristle. It may be in the form of a highly tapered bristle that becomes thinner. Further, the brushes constituting one bristle bundle may have the same diameter, or may have a mixture of brushes having different diameters.

The material of the toothbrush handle including the head 4 may be a thermoplastic resin, and examples thereof include polypropylene, polyethylene, polyester, polyamide, polymethyl methacrylate, cellulose propionate, and ABS. Polypropylene is preferable in terms of physical properties, cost and the like. Further, it is also preferable to form a multicolor molded handle in which these resins are combined with each other or a thermoplastic elastomer.

In the case of the present invention, the side shape of the molten enlarged portion 3 is not limited to the elliptical shape as shown in FIG. 1A, but may be, for example, as shown in FIGS. 4A to 4E. In addition, various other side shapes can be adopted. In addition, hair bundle 1
The center of the cross-sectional shape formed by connecting the outermost circumferences of the brushes 2 and the center of the cross-sectional shape of the molten enlarged portion 3 are not necessarily concentric.

Further, the cross-sectional shapes of the hair bundle 1 and the swelling portion 3 are not limited to the circular shape as shown in FIG. 1B, but various other cross-sectional shapes can be adopted. .
FIGS. 5A to 5K show other examples of the cross-sectional shape of the hair bundle 1 and the molten enlarged part 3. In the case of a non-concentric or non-similar cross-sectional shape as shown in FIG. 5, the overhang dimension L of the molten enlarged portion 3 in each hair bundle 1 is, as shown in the figure, measured from the outer periphery of the hair bundle. The distance to the outer peripheral end of the molten enlarged portion 3 is represented by the dimension of the position where the distance is the minimum.

[0025]

As described above, according to the present invention, after the base end of the bundle of brushes is melted by means of heat or the like to form a molten enlarged part, it is embedded in the flocked surface of the head part. In the toothbrush, the magnification of the cross-sectional area of the molten enlarged part with respect to the total cross-sectional area of the brush constituting the bristle bundle, and the overhang dimension from the outer periphery of the bristle bundle to the outer peripheral end of the molten enlarged part were appropriately determined, so that the quality of the toothbrush was improved. As well as being able to sufficiently secure the flocking strength, which is important as well as a short shot of the handle resin and the protrusion of the injection resin to the outer circumference of the hair bundle,
A so-called burr can be prevented, and a toothbrush excellent in appearance quality can be provided.

[Brief description of the drawings]

FIG. 1 (a) is a side view of a hair bundle and a molten enlarged part,
(B) is a plan view thereof.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a sectional view taken along line BB in FIG.

FIGS. 4A to 4E are side views showing other examples of the side shape of the hair bundle and the molten enlarged part.

FIGS. 5A to 5K are plan views showing other examples of the cross-sectional shape of the hair bundle and the molten enlarged part.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hair bundle 2 Brush 3 Molten enlargement part 4 Head part 5 Flocked surface L Overhang dimension D Embedding depth

 ────────────────────────────────────────────────── ─── 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 (4)

[Claims] 1. A toothbrush embedded in a flocked surface of a head portion after a base end portion of a bristle bundle with a brush is melted by means of heat or the like to form a molten enlarged portion, wherein a cross-sectional area of the molten enlarged portion is provided. The toothbrush is 1.2 to 6 times larger than the sum of the cross-sectional areas of the brushes constituting the bristle bundle. 2. The toothbrush according to claim 1, wherein the magnification is 1.5 to 4 times. 3. A toothbrush buried in a flocked surface of a head portion after forming a molten enlarged portion by melting a base end portion of a bristle bundle with a brush by heat or the like. A toothbrush characterized in that the overhang dimension to the outer peripheral end of the portion is 0.05 to 3.0 mm. 4. The overhanging dimension is 0.1 to 1.5 mm.
4. The toothbrush according to claim 3, wherein: