JP4159739B2 - Brush handle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a brush handle such as a toothbrush and a hair brush.
[0002]
[Prior art]
When the brush is injection-molded with a transparent resin, the handle portion is thick, and voids (voids) are generated inside. For this reason, the brush handle is formed only by a resin that forms a single layer without transparency.
[0003]
In order to give a transparent feeling, some of them are multilayered. However, these are known to be formed by separately molding and bonding, or by insert molding.
[0004]
[Problems to be solved by the invention]
However, in order to give transparency by bonding or insert molding, there are problems that the manufacturing process becomes two or more steps, the molding time becomes long, and the cost increases.
[0005]
In addition, since it is necessary to consider the adhesiveness and safety of the material, there is a problem that the degree of freedom in design is low.
[0006]
An object of the present invention is to provide a thick brush handle with a high degree of design freedom and transparency, in a simple manner.
[0007]
[Means for Solving the Problems]
The invention of claim 1 is a handle for a brush in which an inner layer made of a colored resin is embedded in an outer layer made of a transparent or translucent resin , wherein the first inner layer is molded inside the outer layer, A transparent intermediate layer is molded inside the first inner layer, a second inner layer is molded inside the transparent intermediate layer, and the color density of the first inner layer is lower than the color density of the second inner layer. Yes, at one end of the brush handle on the resin injection side, wrapping the second inner layer with a part of the first inner layer, and toward the other end of the brush handle, the first inner layer is A portion that does not enclose the second inner layer is formed .
[0008]
Here, transparent or translucent means that the inner layer is visible, and may be colored and transparent.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1 and 2 show a procedure for molding a thick toothbrush handle 10 using the injection mold 1 as shown in the following (1) to (4) by the sandwich injection molding method. Here, the sandwich injection molding method uses two or more kinds of materials, and the material is obtained by alternately switching two sets of injection mechanisms from the same gate of the mold for one set of molds. It is a method of injection and molding. Here, the mold temperature was 20 ° C., the injection resin temperature was 250 ° C., and the injection pressure was 112 kgf / cm ² .
[0010]
(1) A transparent (or translucent) resin is injected into the mold 1 for 3.0 seconds to mold the outer layer 11 (FIG. 1A). As the transparent resin, for example, polyethylene terephthalate (PET), polystyrene (PS), acrylonitrile styrene (AS), polyacryl (PMMA), or the like can be used. Here, a colorless and transparent polyethylene terephthalate resin was used.
[0011]
(2) A small amount of colored resin is injected into the outer layer 11 for 0.3 sec to form the first inner layer 12 (FIG. 1B). As the colored resin, for example, a resin obtained by adding a colorant to the transparent resin described in (1) above can be used.
[0012]
(3) The same transparent resin as in the above (1) is injected into the first inner layer 12 for 1.2 seconds to form the transparent intermediate layer 13 (FIG. 1C).
[0013]
(4) A colored resin of the same color as in (2) above is injected into the transparent intermediate layer 13 for 2.0 seconds to form the second inner layer 14 (FIG. 1 (D)), and finally the transparent resin is applied. Injection is completed for 4.5 seconds to complete filling (FIG. 1 (E)). The last injection of the transparent resin is preferable from the viewpoint of productivity because the next molding starts from the transparent resin, and is also preferable from the viewpoint that the colored resin can be completely embedded. In the handle 10, as shown in FIG. 2, a part (base) of the first inner layer 12 on the outer side wraps the second inner layer 14 on the inner side, and the color density of the first inner layer 12 is set to the second inner layer 14. The color density is lower than the color density. The first inner layer 12 is stretched long and thinly with a small amount of the colored resin to have a lower concentration than the second inner layer 14.
[0014]
In the handle 10, the shape of the inner layers 12, 14 is changed by appropriately changing the injection start timing and the injection end timing of the colored resin in the above (2) and (4) within the range where the handle 10 is completely filled. Can be transformed.
[0015]
The colored resin that constitutes the inner layers 12 and 14 is not limited to the transparent resin that constitutes the outer layer 11 and the transparent intermediate layer 13, but is different from the transparent resin that constitutes the outer layer 11 and the transparent intermediate layer 13. The material may be used. Further, the colored resins constituting each of the inner layers 12 and 14 are not limited to the same material, but may be different materials, or the colors may be different from each other. Further, since the inner layers 12 and 14 and the transparent intermediate layer 13 are enclosed in the outer layer 11, no adhesiveness is required between the outer layer 11, the first inner layer 12, the transparent intermediate layer 13, and the second inner layer 14.
[0016]
According to this embodiment, there are the following operations.
(1) Since the outer layer 11 of the handle 10 is formed of a transparent or translucent resin and the inner layers 12 and 14 are formed of a colored resin, voids (voids) can be made invisible even if the handle 10 is thick. Here, the thickness means a thickness of 3 mm or more, and the effect of the present invention is particularly remarkable when applied to a handle having a thickness of 5 mm or more. Further, the term “transparent or translucent” means that the inner layer is visible, and it may be colored and transparent. At this time, two or more inner layers 12 and 14 inside the outer layer 11 are formed of colored resin, and the inner layer 14 closer to the inner side is covered by a part of the inner layer 12 closer to the outer side, and the color density of the inner layer 12 closer to the outer side is set. By making the density lower than the color density of the inner layer 14 on the inner side, the inner layer 12 on the outer side is colored and translucent, and the inner layer 12 on the outer side does not wrap from the portion wrapping the inner layer 14 on the inner side. Thus, it is possible to obtain a change in color tone that gradually reduces the color density toward. Therefore, it is possible to obtain a beautiful handle 10 having a transparent feeling and a change in color tone.
[0017]
(2) The material of the handle 10 can be adjusted by using different materials for the outer layer 11 and the inner layers 12 and 14. That is, various resins can be used as the inner layers 12 and 14, and the degree of freedom in designing the handle 10 can be improved. For example, the handle 10 having high bending strength can be obtained by using a flexible resin for the outer layer 11 and a hard resin for the inner layers 12 and 14. Here, not only a hard resin is used for the inner layers 12 and 14, but also the strength thereof may be improved by kneading a pigment or the like. In particular, in the present invention, even when a transparent resin that is easily damaged by fatigue is used due to continuous bending load during use, the transparent resin is molded integrally with the colored resin, and the colored resin is completely formed into the transparent resin. Since it is embedded, the inner layers 12 and 14 and the outer layer 11 do not peel or fall off, and fatigue failure can be prevented. Further, the handle 10 having a certain chemical resistance performance can be obtained at low cost while using a resin having a high chemical resistance only for the outer layer 11 and using a resin having a low chemical resistance for the inner layers 12 and 14. Moreover, the resin which should avoid use etc. in an oral cavity is also used as the inner layers 12 and 14, and this is completely enclosed with the outer layer 11, Therefore A health problem can be avoided.
[0018]
3 and 4 show the procedure for molding the thick toothbrush handle 20 using the injection mold 2 as shown in the following (1) and (2).
[0019]
(1) A transparent (or translucent) resin is injected into the mold 2 to mold the outer layer 21 (FIG. 3A).
[0020]
(2) A colored resin is injected into the outer layer 21 to mold the inner layer 22 (FIG. 3B), and finally a transparent resin is injected to complete the filling (FIG. 3C). 4). The last injection of the transparent resin is preferable from the viewpoint of productivity because the next molding starts from the transparent resin, and is also preferable from the viewpoint that the colored resin can be completely embedded.
[0021]
In the handle 20, the shape of the inner layer 22 is changed as shown in FIG. 3D or FIG. 3D by appropriately changing the injection start timing and injection end timing of the colored resin in the above-described (2) within the range where the handle 20 is completely filled. It can be transformed as shown in (E).
[0022]
The colored resin constituting the inner layer 22 is not limited to the transparent resin constituting the outer layer 21 added with a colorant, but may be made of a material different from that of the transparent resin constituting the outer layer 21. Further, since the inner layer 22 is wrapped inside the outer layer 21, no adhesiveness is required between the outer layer 21 and the inner layer 22.
[0023]
According to this embodiment, there are the following operations.
(1) Since the outer layer 21 of the handle 20 is formed of a transparent or translucent resin and the inner layer 22 is formed of a colored resin, voids (voids) can be made invisible even if the handle 20 is thick.
[0024]
(2) The material of the handle 20 can be adjusted by using different materials for the outer layer 21 and the inner layer 22. That is, various kinds of resins can be used as the resin of the inner layer 22, and the degree of freedom in designing the handle 20 can be improved. For example, the handle 20 having high bending strength can be obtained by using a flexible resin for the outer layer 21 and a hard resin for the inner layer 22. Further, the handle 20 having a certain chemical resistance performance can be obtained at a low cost while using a resin having a high chemical resistance strength only for the outer layer 21 and using a resin having a low chemical resistance strength for the inner layer 22. In addition, a resin that should be avoided from being used in the oral cavity is also used as the inner layer 22 and completely wrapped with the outer layer 21, thereby avoiding sanitary inconvenience.
[0025]
In addition, the molding machine used for implementation of this invention should just be a thing which can project a subsequent injection material into the inside of a prior injection material, for example, a FN-D color mixing molding machine (made by Nissei Plastic Industry Co., Ltd.) is mentioned.
[0026]
【The invention's effect】
As described above, according to the present invention, a thick brush handle having a high degree of design freedom and transparency can be provided by a simple method.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a procedure for forming a toothbrush.
FIG. 2 is a cross-sectional view taken along line II-II in FIG.
FIG. 3 is a schematic view showing another forming procedure of the toothbrush.
4 is a cross-sectional view taken along line IV-IV in FIG.
[Explanation of symbols]
10 handles
11 outer layers
12 1st inner layer
13 Transparent intermediate layer
14 Second inner layer

Claims (2)

A brush handle in which an inner layer made of a colored resin is embedded in an outer layer made of a transparent or translucent resin ,
A first inner layer is molded inside the outer layer;
A transparent intermediate layer is molded inside the first inner layer,
A second inner layer is formed inside the transparent intermediate layer;
The color density of the first inner layer is lower than the color density of the second inner layer;
Wrapping the second inner layer with a part of the first inner layer at one end of the brush handle on the resin injection side,
The brush handle, wherein the first inner layer forms a portion that does not wrap the second inner layer toward the other end of the brush handle. A method for molding a brush handle according to claim 1,
A method for forming a handle for a brush, in which a transparent or translucent resin is injected into a mold and then a colored resin is injected into the transparent or translucent resin.

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