Method for producing a toothbrush, and toothbrush

Abstract

A grip body of a body care article, such as toothbrush, includes a grip part, a neck part and a head part. The grip body includes a first and a second material component of a thermoplastic plastic. The first and the second material component have a common injection point that is arranged outside a mould partition line formed by the mould partition.

1 . A grip body of a body care article, such as toothbrush, comprising a grip part, a neck part and a head part, wherein the grip body comprises a first and a second material component of a thermoplastic plastic,
 wherein the first and the second material component have a common injection point that is arranged outside a mould partition line formed by the mould partition.   
     
     
         2 . The grip body according to  claim 1 , wherein the grip body comprises a third material component that is preferably soft-elastic, and for example consists of a thermoplastic elastomer. 
     
     
         3 . The grip body according to  claim 1 , wherein the grip part comprises a jacket body of the first material component and a core body of the second material component that is at least partly enveloped by the jacket body. 
     
     
         4 . The grip body according to  claim 3 , wherein the second material component preferably towards the head part breaks out of the enveloping jacket body of first material component and comes to the surface, and preferably the head part consists completely of the second material component. 
     
     
         5 . The grip body according to  claim 3 , wherein the grip body, with the exception of the injection point, comprises a core body of the second material component that is completely surrounded by the jacket body of the first material component. 
     
     
         6 . The grip body according to  claim 1 , wherein the common injection point of the first and second material component is arranged on the front side or rear side of the grip body, preferably in the grip part and preferably on the rear side. 
     
     
         7 . The grip body according to  claim 1 , wherein the grip body in the grip part and/or neck part comprises a through-opening, by way of which the grip body is divided into two part-arms, and each part-arm comprises a jacket body of the first material component and a core body of the second material component that is enveloped by the jacket body, wherein the two line-like core bodies, at the coming-together of the part-arms towards the head part:
 a. reunify, and run further towards the head part as a common, line-like core body which is enveloped by the jacket body, or   b. run further in a manner parallel to one another towards the head part as separate part-lines that are enveloped by the jacket body,   and the line-like core body or bodies preferably run out in the neck part or head part in a tongue-like manner.   
     
     
         8 . The grip body according to  claim 1 , wherein the first and/or the second material component is a hard component, preferably of a polypropylene (PP) polycyclohexylene dimethylene terephthalate (PCT-A), polyethylene (PE) or a styrene polymerisate, such as styrene acrylonitrile (SAN). 
     
     
         9 . The grip body according to  claim 1 , wherein the first and/or second material component is a soft component, preferably of a thermoplastic elastomer. 
     
     
         10 . A method for manufacturing an elongate grip body of a body care article, such as toothbrush, of at least two material components of a thermoplastic plastic, comprising the injection moulding of the material components in an injection moulding tool by way of a hot-runner method,
 wherein at least two plastic components are injected via a common injection point into a common tool cavity of the injection moulding tool by way of the following steps:   injection moulding a first material component into the tool cavity and a partial filling of the tool cavity with the first material component through a hot-runner nozzle;   cooling the injected first material component in the tool cavity, wherein at least one flowable soul is retained in the first material component;   injection moulding a second material component into the tool cavity of the injection moulding tool through the same hot-runner nozzle and further, preferably complete filling of the tool cavity with the second material component;   wherein the flowable soul of the first material component previously injected into the tool cavity is displaced in the material flow direction during the injection moulding of the second material component, and the first material component that preferably bears on the cavity wall and is at least partly solidified at least partly surrounds the flowing-in second material component.   
     
     
         11 . The method according to  claim 10 , wherein the tool cavity is designed as a longitudinal cavity with a longitudinal axis, and the injection point lies outside a mould partition line of the tool cavity, and the injection point is preferably designed such that the first and the second material components are injected transversely to the longitudinal axis of the tool cavity, preferably at an angle of between 85° and 90° between the longitudinal axis and the closure direction of the needles, into the tool cavity. 
     
     
         12 . The method according to  claim 10 , wherein the ratio of the injected volume of the first material component to the total volume of the tool cavity and the ratio of the flowable soul of the first material component to the unfilled volume of the tool cavity is selected such that the subsequently injected second material component breaks out of the first material component surrounding this, in the material flow direction, and in this manner an end section of the tool cavity that is at the front in the material flow direction is completely and exclusively filled with the second material component. 
     
     
         13 . The method according to  claim 10 , wherein the ratio of the injected volume of the first material component to the total volume of the tool cavity and the ratio of the flowable soul of the first material component to the unfilled volume of the tool cavity is selected such that the second material component displaces the flowable soul of the first material component in the material flow direction, wherein the displaced soul in the material flow direction fills a front end section of the tool cavity, so that the second material component is completely surrounded by the first material component, preferably except for at the injection point. 
     
     
         14 . The method according to  claim 10 , wherein
 a. the total volume of the tool cavity minus the total volume of the injected first material component is smaller than the flowable soul displaced by the second material component or   b. the total volume of the tool cavity minus the total volume of the injected first material component is larger than or equal to the flowable soul displaced by the second material component.   
     
     
         15 . The method according to  claim 10 , wherein the tool cavity in the material flow direction is temporarily divided into at least two part-channels that reunify again, and on injecting the second material component, the flowable soul of the first material component is displaced in the material flow direction into a front end section of the tool cavity and the second material component amid the formation of two part-lines follows the displaced soul through the part-channels, wherein
 a. the two part-lines subsequently to the unification of the two part-channels reunify, and run further as a common, line-like core body enveloped by the jacket body, towards the head part, or   b. the two part-lines subsequently to the unification of the two part-channels run separately and parallel to one another amid the formation of two end-sections running out in a tongue-like manner.   
     
     
         16 . The method according to  claim 10 , wherein the first material component is injected again subsequently to the injection of the second material component, so that the surface at the injection point is formed from the first material component. 
     
     
         17 . An injection moulding tool for carrying out a method according to  claim 10 , wherein the injection moulding tool is a hot-runner tool comprising a hot-runner nozzle that runs out into a tool cavity and that is designed as a needle closure nozzle, wherein the hot-runner nozzle comprises a first closure needle designed as a hollow needle as well as a second closure needle that can be inserted into the hollow needle, and the first closure needle in the hot-runner nozzle with an outwardly lying channel wall forms an outer material feed channel and with its axial through-opening forms an inner material feed channel,
 wherein the hot-runner nozzle comprises a cylinder-shaped outlet opening, and the first closure needle comprises a cylinder-shaped end section that is designed for introduction into the cylinder-shaped outlet opening with a positive fit, in order thus, amid the formation of a cylindrical sealing surface running parallel to the closure direction, to seal the outer material feed channel to the tool cavity.   
     
     
         18 . The injection moulding tool according to  claim 17 , wherein the second closure needle comprises a cylinder-shaped end section, and the through-opening of the first closure needle in its end section is cylinder-shaped, so that the second closure needle can be inserted into the through-opening at the cylinder-shaped end section of the first closure needle with a positive fit, in order thus, amid the formation of a cylindrical sealing surface running parallel to the closure direction, to seal the inner material feed channel to a tool cavity.