EP3945934A1

EP3945934A1 - Brush, in particular toothbrush and method for producing same

Info

Publication number: EP3945934A1
Application number: EP20715347.9A
Authority: EP
Inventors: Jens BREITBACH
Original assignee: M&C Schiffer GmbH
Current assignee: M&C Schiffer GmbH
Priority date: 2019-03-28
Filing date: 2020-03-27
Publication date: 2022-02-09
Also published as: DE102019204397A1; WO2020193760A1; US20220151369A1

Abstract

The invention relates to a brush and to a method for producing same, which permit a more efficient use of the introduced plastics and thus a more cost-effective production, and proposes a brush, comprising a brush head (28) having bristle filaments (6), a brush neck, and a grip handle, arranged one behind the other in the longitudinal direction of the brush, in which brush a bristle support (32) that holds the bristle filaments (6) is formed from a hard component (16) and the grip handle is formed from a foamed plastics material (24). In the method according to the invention, in order to form a bristle support (32) that holds bristle filaments (6), a first plastics component (16) is injected into a first mould cavity (14), the bristle support (32) is transferred to another mould cavity (22) and in another moulding cycle a foamable plastics material (24) is introduced into the other mould cavity (22) and is foamed in said other mould cavity (22).

Description

Brushes, in particular toothbrushes, and processes for their manufacture

The present invention relates to a brush, in particular a toothbrush and a process for the manufacture thereof.

A brush, in particular a toothbrush, has a brush body that carries bristle filaments. The brush body has a brush head to which the bristle filaments are attached, a handle for handling the brush and a brush neck located in between.

Such brushes in the form of toothbrushes have been known for a long time.

EP 1 1 10 478 A1, which goes back to the applicant, relates to a method for producing a toothbrush. In this process, an injection mold is initially equipped with several Bors tenbündeln, each consisting of a variety of bristle filaments. The bristle bundles are first melted on the fastening side so that a thickening is formed there. This thickening is overmolded with a first plastic component in a first injection mold. The intermediate product is then converted into another, larger injection mold and encapsulated with a second plastic component.

The process should be able to produce visually appealing brushes. Because the ends of the bristle filaments on the fastening side can usually only be overmolded with a limited injection pressure, since the bristle filaments protrude through the cavity formed for the overmolding. For this purpose, a hole-shaped channel is formed in the injection mold, which holds the respective bristle bundle. However, there is no complete tightness at this point. For example, when injecting around the thickening and the fastening-side end of the bristle bundle, a reduced injection pressure must be applied, which, however, leads to a surface of the intermediate product injected in this way that meets the visual and design requirements that are to be placed on a hygiene product such as a toothbrush, not always fair. The intermediate product in the second mold cavity is overmolded with a further plastic component. The second mold cavity is sealed by surfaces of the intermediate product, which are formed by the first plastic component, so that higher injection pressures can act in the second mold cavity.

The present invention aims to provide a brush and a method for producing it, which allows more efficient use of the plastic used. This should make it possible, please include to manufacture brushes of the type mentioned, in particular toothbrushes, more cheaply. To solve this problem, a brush with the characteristics of claim 1 is proposed with the present invention.

This brush can be a toothbrush which, in a manner known per se, has a brush head, a brush neck and a handle handle, the brush neck being provided between the brush head and the handle handle. These components are arranged one behind the other in the longitudinal direction of the toothbrush. They usually form the brush body of the toothbrush, which is an elongated brush body. According to the invention, a bristle element holding boron carrier of the brush is formed from a hard component. This hard component is a conventional plastic that is able to hold the bristle filaments, regularly several bristle filaments combined to form a bristle bundle, on the brush head with the necessary pull-out strength. The filaments can be held without anchors in the manner described above. For this purpose, the bristle filaments are embedded in the hard component forming the bristle carrier when the bristle carrier is formed. The filaments can also be attached with an anchor. In this procedure, the bristle carrier is initially produced, usually by injection molding, and then, usually after the brush body has been completely finished, the bristle filaments are attached to the brush head.

With the brush according to the invention, the brush head can have several bristle carriers. The bristle carriers are designed as fastening elements for fastening the bristle filaments. Individual bristle carriers, each carrying at least one bristle filament or a bristle bundle, can be articulated to another bristle carrier. The bristle carriers can be connected to one another via film hinges, so that all of the bristle carriers of the brush head can be molded in a uniform injection molding cycle.

The brush according to the invention has a handle made of a foamed plastic. The foamed plastic can also form the brush neck. The foamed plastic allows the production of a brush body in the usual and previously known dimensions, but using a reduced amount of plastic. The foaming leads to an improved use of the amount of plastic material introduced during injection molding to form the brush body. The brush is lighter overall. It can be produced more cost-effectively, since a reduced weight of plastic has to be used to shape the brush body without sacrificing the dimensional design of the brush. From DE 100 34 839 A1, which can be traced back to the applicant, it is known to overmold this handle handle several times with an inexpensive recyclate to produce a thick-walled handle of a toothbrush, so that the handle is formed by several ring-like layers around a core made from a high-quality, virgin plastic component becomes. Such a design cannot be produced economically in the field of toothbrushes, since available recycled material regularly contains unspecified ingredients and additives, so that the recycled material does not meet the requirements for the chemical purity of hygiene articles (FDA conformity).

The bristle carrier is preferably designed as a bristle carrier limiting itself to the brush head. The handle and the brush neck are made of the foamed plastic. The connection can take place, for example, according to EP 3 087 864 A1.

The foamed plastic can also form parts of the brush head. In the case of several bristle carriers that are provided in the area of the brush head, the foamed plastic can connect them to one another or transfer them. As a result, the brush head is also shaped by the outer enclosure with the foamed plastic into an aesthetically pleasing-looking segment of the brush body that is designed with a reduced plastic weight.

In a preferred development of the invention, the bristle carrier is therefore at least partially surrounded by the foamed plastic.

According to a preferred development of the present invention, the brush head, the handle and the brush neck are made of the foamed plastic and the hard component. In other words, the brush according to the invention is preferably formed solely by the brush body formed from the two components and the cleaning elements attached to it. These cleaning elements can be bristle filaments or also flexible cleaning elements, for example made of a TPE. The restriction to the use of only two plastic materials forming the brush body simplifies production and increases economic efficiency.

In a preferred variant of the invention, the foamed plastic has essentially the same hardness as the hard component. The hardness, in particular the tensile strength, of the foamed plastic is preferably at least 50%, preferably at least 80% of that of the hard component. In this way, it is possible to produce a sufficiently stable handle while using less material. In a further variant of the invention, the foamed plastic is sufficiently compressible in itself so that the brush provides a pleasant feel. In this case, haptic elements formed from a separate material on the outer surface, in particular of the handle, can be dispensed with. The injection molding around the brush body with a soft, elastic plastic compound, as is known from the prior art for the formation of haptic elements, can be omitted.

A hard component in the context of the present invention is in particular an engineering plastic such as PA, PE or PP. With a view to the desired pull-out strength of the bristle filaments in relation to the brush body, the hard component has a tensile strength of preferably at least 80 MPa, particularly preferably at least 90 MPa, most preferably at least 500 MPa.

The area of the brush body formed by the foamed plastic is preferably shaped as an integral foam. With regard to the hygienic requirements, the foamed plastic forms a closed, thick outer skin, so that the surface areas of the brush body that are made of the foamed plastic cannot absorb moisture and soiling. The core of the foamed material, on the other hand, is provided with a cellular structure, the density of the foamed material usually decreasing from the outside inwards. Such an integral foam can be the result of mechanical or physical foaming. The foamed plastic can just as easily be shaped by chemical foaming.

As far as the foamed plastic extends into the brush head, the design should be such that the bristle filaments protrude through an upper outer surface of the brush head and protrude from it, which is formed by the hard component, whereas adjacent to this protruding outer surface and in the same plane or extension as this the surface is formed by the foamed plastic. This is usually achieved by the foamed plastic circumferentially surrounding the upper outer surface. When looking at the top of the brush head, the hard components in the area of the bristle filaments and the foamed plastic can be seen where no bristle elements are provided. This configuration offers further functional advantages. For example, the foamed plastic in the area of the brush head provides a softness that serves as a mucous membrane protection when the brush is used as a toothbrush in the mouth. This allows a synergistic effect to be used. On the one hand there is material saved for shaping the brush body; on the other hand, functional areas are formed on the brush head by the foamed plastic.

The same applies to technical functional elements of the brush head such as joints that are to be shaped or formed between individual bristle carriers. Due to the reduced rigidity of the foamed plastic compared to a conventional hard component, the bristle carriers can be easily pivoted relative to one another on the brush body.

By arranging the foamed plastic on a rear surface of the brush head opposite the upper outer surface, a tongue scraper can be formed from the foamed plastic there. Here, too, the inherent compressibility of the foamed plastic, which is preferably present, allows a corresponding functionality by means of which mucous membranes within the oral cavity can be treated effectively and which a conventional hard component does not provide.

If the rear surface is formed completely from the foamed plastic, corresponding functional elements can be provided over a large area on the rear surface. In this way, comprehensive shock protection for the sensitive oral mucous membranes can be realized, by means of which the bristle carrier or bristle carriers formed from the hard component are almost completely enveloped. Only the surface directly penetrated by the bristle filaments, which due to the spacing of the bristle filaments cannot come into contact with the mucous membranes of the mouth, is formed from the hard component in this embodiment.

To increase the usefulness of the brush according to the invention, it is proposed according to a preferred development of the present invention to provide the foamed plastic on the rear surface of the brush head so that at least one functional surface formed by the hard component is circumferentially surrounded by the foamed plastic. The functional surface can for example have ribs or knobs which are formed by the hard component and accordingly have a higher mechanical effectiveness compared to the surface to be cleaned.

The connection between the hard component and the solidified foamed plastic material of the brush head can be cohesive and / or form-fitting. A positive connection is created in particular in that the solidified foamed plastic completely or at least almost completely in the hard component sealed up. In the case of an almost complete sealing, only the surface areas of the upper outer surface of the brush head surrounding the periphery of the bristle filaments are formed by the hard component. For example, each individual bundle of bristles can be circumferentially surrounded by a ring of the hard component, which forms an annular surface on the upper outer surface, but which is otherwise formed by the foamed plastic. The surface segments of the brush head usually merge into one another without steps or seams, so that dirt and bacteria cannot settle on the brush head.

As bristle carriers, individual support rings or a uniform grid of rings produced by injection molding can be realized with connecting webs provided as film hinges in between, each individual ring usually carrying a single bristle bundle. The bristle bundle can be fastened in a ring that is closed on the underside, with an anchor, by means of an adhesive or welded connection. A ring as a bristle carrier can also be open on the underside so that the bristle bundle protrudes through the ring and is positively held on the ring surface opposite the upper outer surface via a thickening formed on the bristle bundle and secured to the bristle carrier element with good pull-out strength.

With regard to the procedural aspect of the underlying problem, the present invention proposes a method for producing a brush in which a first plastic component is injected into a first mold cavity to form a bristle carrier and then the intermediate product produced in this way is converted into another mold cavity that it is regularly larger than the first mold cavity and that a foaming plastic is introduced into the further mold cavity in a further molding cycle. This foaming plastic is foamed in the further mold cavity, which results in a form-fitting and / or material connection between the hard component forming the bristle carrier and the solidified foamed plastic.

Further details and advantages of the present invention emerge from the following description of exemplary embodiments of a schematic process control in conjunction with the drawing. In this drawing show:

FIG. 1 shows a schematic sectional view to illustrate a first injection molding step for producing the brush head; FIG. 2 shows an illustration according to FIG. 1 to illustrate the second injection molding step;

FIG. 3 shows a representation according to FIG. 2 for an alternative exemplary embodiment;

FIG. 4 shows a schematic sectional view to illustrate a first injection molding step for the production of a brush head according to an alternative exemplary embodiment;

FIG. 5 shows an illustration according to FIG. 4 to illustrate the second injection molding step for producing the second exemplary embodiment;

FIG. 6 shows a schematic sectional view to illustrate the configuration of the second exemplary embodiment of a brush head;

Figure 7 is a schematic sectional view to illustrate the attachment of a

Bristle filaments according to a first variant and

Figure 8 is a schematic sectional view to illustrate the attachment of a

Bristle filaments according to a second variant.

In Figures 1 and 2, two successive steps of the two-component injection molding of a brush body, not shown in detail, is illustrated, which is designed as a brush body of a toothbrush and a brush head shown in the figures in section, a longitudinally adjoining brush neck and a having handle handle adjoining the brush neck.

During production, a perforated field plate 2 is first stuffed with at least one bundle of bristles 4. For this purpose, the bristle filaments 6 forming the bristle bundle 4 are pushed through a hole 8 and melted at the end to form a thickening 10. The perforated field plate 2 is connected to an injection molded half 12 a in order to form a first mold cavity 14 together with an injection molded half 12 b. In this first mold cavity 14, a hard component 16 is injected as the first plastic component.

After the hard component 16 has solidified, an intermediate product identified by reference numeral 18 in FIG. 1 is removed from the mold. The demolding takes place together with the perforated field plate 2, which is applied sealingly against a second injection-molded half 20a, which forms a second mold cavity 22 with a second injection-molded half 20b and the perforated field plate 2. A foaming plastic 24 is introduced into this second mold cavity 22, which is physically and / or chemically and / or mechanically foamed or foamed. The formation of an integral foam is preferred, so that the foamed plastic 24 with a closed thick outer skin solidifies against the perforated panel 2 surrounding the second mold cavity 22 and the second injection molded halves 20a, 20b, while having a density that decreases towards the inside.

In this context, it should be understood that Figures 1 and 2 show the section through a brush according to the invention only schematically. It goes without saying that the hard component 16, with a view to the desired fastening of the bristle bundles 4, must be designed to be adequately strong around the thickening 10, but on the other hand, with a view to the desired saving of material, the largest possible part of the brush body to be produced by the foamed plastic 24 is to be shaped.

FIG. 3 shows an exemplary embodiment modified compared to FIGS. 1 and 2 after the foaming plastic 24 has been injected. The same components are identified with the same reference numerals. The second exemplary embodiment according to FIG. 3 differs mainly in that an upper outer surface of the brush head 28 shown in cross section through which the bristle bundles 4 protrudes and is identified by reference characters 26 is predominantly formed by the foamed plastic 24. Only a circular ring surface 30 in the present case surrounds the bundle of bristles 4, which is realized in the present case with a round cross section, circumferentially.

Correspondingly, the surface areas of the brush head 28 through which the bristle bundles 4 protrude are formed by the hard component 16, the upper outer surface 26 otherwise predominantly by the foamed plastic 24. The variant shown also leads to a completely form-fitting sealing of the part formed by the hard component 16 and with it Reference numeral 32 identified bristle carrier.

FIGS. 4 to 6 illustrate the production of a second exemplary embodiment of a bristle carrier, identified by reference number 32 in FIG. 6, which has a hard component, identified by reference number 16, which forms a core within bristle carrier 32. According to FIG. 4, this hard component 16 is made in a first mold cavity 14. The mold cavity 14 is - as in FIG. 2 - enclosed by two injection-molded halves 12a, 12b and a pin plate 34 which carries a pin 36 which protrudes into the first mold cavity 14. FIG. 4 illustrates the configuration after the injection of the hard component 16, which surrounds the pin 36.

According to FIG. 5, this intermediate product 18 is transferred into the second mold cavity 22 by offsetting the pin plate 34, which is dimensioned such that a free space remains between the outer surface of the intermediate product 18 and the mold cavity surfaces of the second mold cavity 22. In the present case, this free space is shaped to surround the hard component 16 in the shape of a trough. Now, as in the first embodiment, foamed plastic 24 is introduced into the second mold cavity 22. The foam solidifies with the formation of a skin which solidifies against the surfaces delimiting the second mold cavity 22. Thus, a sealed surface design is also evident in the area through which the pin 36 protrudes and is referred to below as the surface of the brush head 28.

After the bristle carrier 32 has been removed from the mold, the pin plate 34 is also removed. Instead of the pin 36, the bristle carrier 32 now has a blind hole 38.

As FIG. 7 shows, a bundle of bristles 4 can be hammered into the blind hole 38 via a conventional anchor 40 and fastened therein.

In relation to this first variant, FIG. 8 shows a second variant in which the bristle bundle 4 has a thickening 10 formed by melting on, which is introduced into the blind hole 38, which is designed to be shorter in the present case. An annular area of the surface surrounding the blind hole 38 is then plastically deformed so that the material on the surface of the bristle carrier 32 that initially delimits the cylindrical blind hole 38 is displaced radially in the direction of the bristle bundle 4 and the thickening 10 is held in the blind hole 38 in a form-fitting manner .

In a variant, for example, by moving the pin 36 relative to one another, the intermediate product 18 can also be arranged at a distance from the pin plate 34 so that the core formed by the hard component 16 is basically completely surrounded by the foamed plastic 24.

A single core formed by the hard component 16 can be provided for each individual bristle bundle 4. The core can also be formed by a ring through which the bundle of bristles protrudes, but otherwise within the foamed plastic Substance 24 is added, the bristle bundle 4 on the back facing away from the front surface of the boron tenträgers 32 by the thickening 10 relative to the ring is positively fixed.

The fastening of the bristle bundle 4 formed by the hard component 16 can then have various specific designs.

List of reference symbols

Perforated panel

Bristle bundles

Filament

hole

thickening

a first injection-molded half

b first injection-molded half

first mold cavity

Hard component

Intermediate product

a second injection-molded half

b second injection molding half

second mold cavity

foamed plastic

upper outer surface

Brush head

Ring surface

Bristle carrier

Pegboard

pen

G round hole drilling

anchor

Claims

Expectations

1.Brush, in particular toothbrush, with a brush head (28) carrying bristle filaments (6), a brush neck and a handle which are arranged one behind the other in the longitudinal direction of the brush,

characterized,

that a bristle carrier (32) holding the bristle filaments (6) is made from a hard component (16) and the handle is made from a foamed plastic (24).

2. Brush according to claim 1, characterized in that the bristle carrier (32) is designed as a bristle carrier element restricting itself to the brush head (28) and that the handle and the brush neck are formed from the foamed plastic (24).

3. Brush according to one of claims 1 or 2, characterized in that the bristle carrier (32) is at least partially surrounded by the foamed plastic.

4. Brush according to one of the preceding claims, characterized in that the brush head, the handle and the brush neck are made of the foamed plastic (24) and the hard component (16).

5. Brush according to one of the preceding claims, characterized in that the brush head (28) has several bristle carrier elements which are connected to one another by the foamed plastic (24).

6. Brush according to one of the preceding claims, characterized in that the bristle filaments (6) protrude from an upper outer surface formed by the hard component (26) of the brush head (28), which is circumferentially surrounded by the foamed plastic (24).

7. Brush according to claim 6, characterized in that the foamed plastic (24) is provided on a rear surface of the brush head provided opposite to the upper outer surface.

8. Brush according to claim 7, characterized in that the rear surface is formed from the foamed plastic (24).

9. Brush according to claim 8, characterized in that the foamed plastic (24) circumferentially surrounds a functional surface formed by the hard component (16) and exposed on the rear surface.

10. Brush according to one of the preceding claims, characterized in that the hard component has a tensile strength of at least 500 MPa.

11. A method for producing a brush, in particular a brush head provided with bristle filaments, a handle handle and a toothbrush having an intermediate brush neck, by injection molding, in which a first plastic composite is used to form a bristle filament (6) holding the bristle carrier (32) Component (16) is injected into a first mold cavity (14), characterized in that the bristle carrier (32) is converted into a further mold cavity (22) and in a further molding cycle a foaming plastic (24) is transferred to the further mold cavity (22) ) is introduced, which foams in the further mold cavity (22).

12. The method according to claim 11, characterized in that the bristle filaments (6) are embedded in the first plastic component (16) when the bristle carrier (32) is formed.

13. The method according to claim 11, characterized in that the bristle filaments (6) are attached to the bristle carrier (32) after the bristle carrier (32) has been removed from the mold.

14. The method according to any one of claims 11 to 13, characterized in that the bristle carrier (32) is formed as a on the brush head (28) limiting Borstenträ gerelement and that the handle and the brush neck from the foaming plastic (24) formed will.

15. The method according to any one of claims 11 to 14, characterized in that the foaming plastic (24) is foamed physically or mechanically.