EP1859705A1 - Brush and method for its production - Google Patents

Abstract

The method involves forming a base body (5) with at least one shell that is open upwards and essentially closed downwards, at least one bundle of bristles (24) set into the shell at the thicker fixing end and fixing the bristles by filling the shell with plastic (30). The shell is filled by injecting the plastic through an injection opening formed in the shell. An independent claim is also included for a brush, especially a toothbrush.

Description

The present invention relates to a brush, in particular a toothbrush and a method for its production.

Modern brushes, in which the bristle field can be formed by differently sized and differently shaped bristle bundles, such as are used in particular for dental care, are nowadays usually produced with anchorless attachment of the bristle bundles to the brush head. For this purpose, the attachment-side ends of the bristle bundles are melted to form a thickening. The attachment-side ends of the bristle bundles are then inserted and overmolded in an injection mold. Regularly, the thickenings are hereby arranged at a distance from the top of the brush head projected through by the bristle bundles. Usually, the bristle bundles are connected in this way with a handle body, a brush neck and a brush head forming body. However, there are various variations of the method, which is sometimes based on the knowledge that the bristle bundles are intended to seal with their thickening outwardly penetrated by the bristle bundle form.

So is out of the EP 0 623 298 a method for producing a toothbrush is known in which the bristle bundles are introduced into channels which are formed on a support plate. The usage end is then melted. The case formed thickening is applied against the channels of the carrier plate. The support plate is finally overmolded from the back to fix the attachment-side ends and smoothly cover to meet the hygienic requirements that are made in particular to toothbrushes.

At one of the EP 1 136 017 known methods, the bristle bundles are introduced into channels, which are formed on a small plate, which is also integrated into the brush to be produced. The fastening-side ends of the bristle bundles are melted and shaped according to this prior art, preferably in such a way that the melt produced by heating the fastening-side ends forms a form-fitting manner in the manner of a backing layer on the small plate.

The present invention is based on the problem to provide a method for producing a brush and a brush produced by the method, which meets the highest optical and hygienic requirements. In particular, to be produced by the method according to the invention, a brush whose brush head carries a cleaning element that can be varied in terms of shape and size within wide limits. In this case, the present invention also wants to specify a brush that can meet the hygienic, optical and technical requirements that are placed on high-quality brushes, in particular toothbrushes by combining different materials.

To solve this problem, the present invention provides a method having the features of claim 1. In this method for producing a brush, a brush body made of plastic is first formed, which forms at least one shell which is open towards the top and essentially closed at the bottom. The upper side of the brush base body is understood to mean that side which is surmounted by the cleaning elements, namely the bundles of bristles, and which regularly lies opposite the surface to be cleaned. At this top of the brush head body is open, but has a staggered thereto provided in the bottom, which forms the bottom of the there substantially closed shell. This shell has edges which preferably follow substantially the outer contour of the brush head body. Thereafter, preferably, a circumferential, relatively thin edge protrudes from the bottom surrounding the shell circumferentially. In this shell, at least one bristle bundle is inserted with its fastening-side end. At this attachment-side end has been formed by melting before insertion into the shell of a thickening. The thickening is usually arranged at a distance from the upper edge of the shell in this. Then the shell is filled with plastic. This plastic is filled in the molten state and settles upon solidification, for example by cooling and / or crosslinking, to the bottom and the inner edge of the shell and includes the thickening of the attachment-side end of the bristle or bundles. As a result, the bristle bundle is fixed to the brush head body.

According to the inventive method, the shell is closed substantially at the bottom, which precludes that the shell may have in its bottom or at its edge an injection port through which the plastic is injected into the shell.

This injection opening is preferably sealed in this case. The brush head body may have one or more shells into which one or more bundles of bristles protrude. The filling of the plastic can be done up to the upper edge of the shell. Just as well, the plastic can also be filled the edge slightly outstanding. If, for example, a thermoplastic elastomer is used as the plastic for filling the shell, it can project beyond the upper edge of the brush head body formed, for example, from a hard component so as to produce an effective mucous membrane protection which prevents the toothbrush from spreading the oral mucosa against the brush body formed from the hard component nudge. If a plurality of shells are formed on the brush head body, they can be filled in relation to the longitudinal extent of the bristle bundles in diverging altitudes with the plastic to create a contoured, projected by bristle bundles surface of the brush head. The areas of different heights can merge intermittently or continuously.

For shaping the upper side of the surface projected by the bristle bundles, a bristle field having a plurality of bristle bundles is stuffed in a perforated field plate which has holding channels for the bristle bundles corresponding to the bristle field. Each individual channel is stuffed with a bundle of bristles. The perforated field plate is applied when filling the shell at its upper edge and thus covers the opening formed by the shell. To avoid post-processing steps, the perforated field plate is preferably applied to the upper edge of the shell such that the perforated field plate seals the shell. For this purpose, the shell preferably has a circumferential edge in the circumferential direction.

The inventive method offers the possibility to fix the bristle bundles with a relatively small injection unit to the brush head body. For this purpose, preferably only the shell must be filled. The filling of the shell can be filled with a hard component, in particular PP. It is also conceivable, however, to fill the shell with a soft elastic plastic, in particular a thermoplastic elastomer. In such a process management can be formed on the outside of the shell formed by the identical component further functional parts when injecting the soft elastic component into the shell in any case, such as bumpers from the thermoplastic elastomer and / or cleaning elements formed from the thermoplastic elastomer.

According to a preferred embodiment of the brush body after fixing the bristle bundles, i. after filling the shell with the plastic encapsulated on its outside, in particular with a soft elastic plastic component, which serves to further protect the oral mucosa in the manufacture of a toothbrush. During encapsulation, the injection opening provided for filling the shell by injecting the plastic through the wall of the brush base body delimiting the shell is preferably overmolded and thus covered on the outside. The encapsulation should preferably take place in such a way that the circumferential edge of the brush head base body is peripherally encapsulated, whereby a further mucous membrane protection is provided on the outer peripheral surface of the brush head main body preferably formed from a hard component. The encapsulation thus forms a circumferential impact protection. If the shell is filled by spraying the plastic through a relatively thin wall of the shell, this has the advantage that it can be operated with relatively low pressures, since the flow path from the injection point to the shell is extremely low. This has particular advantages for the position of the bristle bundles after fixing them in the shell. At high injection pressures and / or injection speeds, the fundamental problem is that they are displaced from the preset position and fixed in this shifted arrangement and orientation after solidification of the injected plastic mass. Such an impairment need not be feared when injecting at lower speeds and / or lower pressures. The method can thus produce toothbrushes with good quality and exact bundle position.

According to a further preferred embodiment of the present invention, preferably further provided on the outside of the brush head body, usually formed in the longitudinal direction of the bristle bundles slots to form superior cleaning elements from the underside of the brush head body with a thermoplastic elastomer. The longitudinal slots can be closed circumferentially by the material of the brush head body. However, these longitudinal slots are preferably formed by recesses of the brush head main body which are open towards the outside and which, during injection molding, are formed by the brush head main body be closed surrounding injection mold, which acts to form the cleaning elements of the thermoplastic elastomer forming.

With regard to the device-based solution to the problem underlying the invention, a brush, in particular a toothbrush, is provided with the present invention, which comprises a brush head body which forms at least one shell open to the top. In this shell at least one bristle bundle is introduced with its fastening side, provided by melting with a thickened end and fixed by a filled into the shell plastic.

Preferred developments of the brush according to the invention will become apparent from the above description of the method for producing this brush.

Fig. 1

eine perspektivische Draufsicht auf den vorderen Bereich eines Grundkörpers zur Ausbildung eines als Zahnbürste ausgebildeten Ausführungsbeispiels;

Fig. 2

eine perspektivische Unteransicht des in Fig. 1 gezeigten Ausführungsbeispiels;

Fig. 3

die in Fig. 1 gezeigte Ansicht mit an dem Grundkörper vorgesehenen Borstenbündeln;

Fig. 4

die Darstellung nach Fig. 3 einer perspektivischen Längsschnittdarstellung;

Fig. 5

eine Ansicht entsprechend den Figuren 1 und 3 nach dem Füllen des Kunststofs;

Fig. 6

den in Fig. 5 gezeigten Zustand in einer Ansicht gemäß Fig. 2;

Fig. 7

eine Darstellung des vorderen Bereichs einer fertiggestellten Bürste in einer Darstellung gemäß Figuren 3 und 5 und

Fig. 8

das in Fig. 7 gezeigte Ausführungsbeispiel in einer Ansicht gemäß den Figuren 2 und 6.

The present invention will be explained below with reference to an embodiment. In this show:

Fig. 1

a perspective top view of the front portion of a base body for forming an embodiment designed as a toothbrush;

Fig. 2

a perspective bottom view of the embodiment shown in Figure 1;

Fig. 3

the view shown in Figure 1 with provided on the body bristle bundles.

Fig. 4

the illustration of Figure 3 is a perspective longitudinal sectional view.

Fig. 5

a view corresponding to Figures 1 and 3 after the filling of the plastic;

Fig. 6

the state shown in Figure 5 in a view of FIG. 2.

Fig. 7

a representation of the front portion of a finished brush in a representation according to Figures 3 and 5 and

Fig. 8

the embodiment shown in Fig. 7 in a view according to Figures 2 and 6.

To produce a toothbrush, as shown with its front part consisting of brush head 2 and handle 4 in Figures 7 and 8, a hard component is first injected into an injection mold having a mold cavity for forming a brush body. This main body consists of a brush head base body 5, a provided between the thickened handle 4 and the brush head body 5 brush neck 6 and the handle handle 4. The brush body 5 can be encapsulated, subsequently printed and / or decorated.

As can be seen from FIG. 1, the basic brush head body 5 forms a shell 8, which is surrounded by an edge 10 that is essentially corresponding to the circumferential contour of the brush head 2. The shell 8 is bounded and closed on the underside by a bottom 12 which extends parallel to the top of the rim 10. The rear wall 14 provided on the underside of the brush head base body 5 has an injection opening 16, which connects the rear side of the brush head base body 5 with the shell 8. On the outer side of the edge 10, recesses 18 extending at right angles to the upper side of the edge 10 are recessed, which are open to the circumferential outer side of the brush head main body 5. At the position of the recesses 18 of the edge 10 is slightly offset in the direction of the shell 8 inwardly formed.

As can be seen from the view in Fig. 2, the rear wall 14 formed by the brush head body 5 has a front and a rear raised portion 20 which is exposed on the outside of the brush to be produced. The two distal and proximal raised portions 20 enclose therebetween a slightly inwardly offset rear wall bottom 22, whose front and rear ends are aligned with the respective outer edges of the recesses 18. The injection opening 16 is located in the region of the rear wall bottom 22.

The brush head base body 5 shown in FIGS. 1 and 2 is converted into a second injection mold after injection molding by injecting a hard component into a first injection molding tool. This second injection mold is covered by a perforated field plate which is applied to the top of the rim 10. The perforated field plate has holding channels for receiving bundles of bristles 24 corresponding to a bristle field 25 of the brush to be produced (see FIGS. 7 and 8) with regard to the size and arrangement of the bundles of bristles 24. The perforated field plate is filled with the possibly differently sized bristle bundles 24, which are then attached to their attachment side Ends are heated and melted. In the process, a thickening 28 inevitably forms on the individual bristle bundles 24. This thickening 28 is arranged at a distance from the underside of the perforated field plate during installation of the perforated field plate in the second injection mold, as shown schematically in Figures 3 and 4. The figures show the situation after installation of the perforated field plate in the second injection mold and before filling the plastic in the shell 8. As can be seen from Figure 4, the bristle bundles 24 are with their thickening 28 at a distance to the upper edge of the shell 8 circumferentially surrounded by the edge 10 of the shell 8. Through the injection port 16, a plastic, for example, a thermoplastic elastomer is injected into the shell 8 from behind after closing the second injection mold now. The attachment-side ends of the bristle bundles 24 with their thickening 28 are enclosed by the plastic. This solidifies flush with the top of the edge 10. The perforated field plate is in this case against the top of the edge 10 at. After solidification of the plastic and demolding the second injection mold, the intermediate product shown in Fig. 6 can be obtained. In this case, the bristle bundles 24 are received with their thickening 28 in the solidified in the shell 8 filled plastic 30. The plastic 30 should preferably be adhesion-compatible with the hard-shell component forming the brush head base body 5, in particular in the area of the surface of the brush between the brush head base body and the plastic 30 filled in the shell 8 during intensive use of the brush, no slits are formed in which germs and can infiltrate contaminants. However, it is also possible to provide interlocking elements on the shell, which are enclosed in the filling of the shell with the plastic 30 in order to positively connect the body formed from the plastic 30 with the plastic base body 5.

The embodiment shown in Figures 5 and 6 is now encapsulated on the back. In this case, a thermoplastic elastomer is injected into a mold cavity, which extends flush between the raised areas 20 of the rear wall 14 and the intermediate product surrounds circumferentially. The third injection mold further has the recesses 18 continuing and extending in the longitudinal direction of the bristle bundles 24 channels. The injected into the mold cavity of the third injection molding thermoplastic elastomer thus fills the back wall bottom 22 to form a heel-free rear wall of the brush head 2, flows through the recesses 18 and into the adjoining channels to form the edge provided cleaning elements 32 of thermoplastic To solidify elastomer. The toothbrush thus produced is shown with its front portion in Figures 7 and 8.

The sealing of the bristle bundles 24 in the plastic 30 offers the possibility to achieve a high design variation by a suitable choice of the plastic. The basic brush head body 5 merely serves to form a shell, which is hardly recognizable, in particular, during the subsequent external molding on the finished brush. The brush head body forms the mechanical skeleton of the finished brush. By filling the plastic in the shell and encapsulation is possible to realize different designs. By placing the perforated field plate on the edge of the one shell, a smooth termination and transition can be achieved at the top of the brush. The seams on the finished product sometimes to be recognized when using perforated field plates at the point at which the perforated field plate passes into the injection mold within the cavity can be largely avoided. In addition, it is possible to form the projected from the bristle bundles 24 surface of a thermoplastic elastomer, which is particularly recommended in the manufacture of toothbrushes for mucosal protection. The method presented by the present invention can be used economically for the production of mass-produced articles by means of plastic injection molding. Furthermore, it is conceivable in low-pressure filling of plastic to use the brush head body alone as a form mesh, which is covered by the perforated field plate. On a second injection mold, which holds the brush head body back, can be dispensed with in this variant.

LIST OF REFERENCE NUMBERS

2

brush head

4

grip handle

5

Brush head body

6

brushneck

8th

Bowl

10

edge

12

ground

14

rear wall

16

Injection port

18

recess

20

raised area

22

Rear floor

24

bristle bundles

26

bristle

28

thickening

30

plastic

32

cleaning element

Claims (13)

Method for producing a brush, in particular a toothbrush, in which a brush head base body (5) is formed which forms at least one shell (8) which is open to the top and essentially closed at the bottom, at least one bundle of bristles (24) with its fixing side, by fusion a thickened (28) provided end in the shell (8) is used and by filling the shell (8) with plastic (30) the bristle bundle (24) is fixed to the brush head main body (5). A method according to claim 1, characterized in that the shell (8) is filled by injecting the plastic (30) through an injection opening (16) formed on the shell (8). A method according to claim 1 or 2, characterized in that the plastic (30) is injected through the rear wall (14) of the brush head main body (5). Method according to one of the preceding claims, characterized in that a bristle field (26) having a plurality of bristle bundles (24) is padded in a perforated field plate having corresponding retaining channels which, when the shell (8) is filled, are attached to the edge (10) on the upper side ) is created. A method according to claim 4, characterized in that the perforated field plate seals the shell (8) during filling edge. Method according to one of the preceding claims, characterized in that the brush head base body (5) is sprayed as part of a brush main body with a brush neck (6) and a handle handle (4) made of a hard component. Method according to one of the preceding claims, characterized in that the shell (8) is filled with a soft component, in particular a thermoplastic elastomer. A method according to claim 7, characterized in that the thermoplastic elastomer is flush-filled in the shell (8). Method according to one of the preceding claims, characterized in that the brush head base body (5) is encapsulated after fixation of the bristle bundles (24) on its outer side. A method according to claim 9, characterized in that during injection molding over to the filling of the shell (8) by the brush head body (5) recessed injection opening (16) is over-injected. A method according to claim 9 or 10, characterized in that the peripheral edge (10) of the brush head main body (5) is encapsulated circumferentially. Method according to one of claims 9 to 11, characterized in that during encapsulation at least one on the outside of the brush head body (5) in the longitudinal direction of the bristle bundles (24) recessed recess (18) for forming at least one of the top of the brush head main body (5) superior Cleaning element (32) is injected from the bottom with thermoplastic elastomer. Brush, in particular a toothbrush, with a brush head base body (5) which forms at least one shell (8) open to the top, into which at least one bundle of bristles (24) is introduced with its end on the fastening side, provided with a thickening by melting, and through one in the Shell (8) filled plastic (30) is fixed.

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