Patent Publication Number: US-2009229063-A1

Title: Toothbrush

Description:
This invention relates to oral hygiene devices. 
     In particular the invention relates to toothbrushes of the type which incorporate elastomeric lamellae on the surface of their head opposite to the surface from which bristles project. Such lamellae are provided primarily for the purposes of tongue cleaning, i.e. for gently removing deposits which might cause bad breath from the tongue. 
     Toothbrushes of this type are known, see for example GB-A-2 391 462 which discloses a toothbrush having a head with bristles extending from one surface of its head, and thermoplastic elastomeric lamellae extending from the opposite surface, and these elastomeric lamellae may incorporate a flavour. Such a toothbrush, though not incorporating a flavour into its elastomeric lamellae, is sold by the present applicant for example under the trade mark Dr.BEST™ Duo Protekt. 
     There remains an ongoing need to provide improved forms of such toothbrushes, and it is an objective of this invention to provide such an improvement. 
     According to this invention an oral hygiene implement is provided, having at least one elastomeric oral hygiene element made of a thermoplastic elastomer material having a hardness in the range ShoreA 20-50 and a composition comprising 100-200 parts of a thermoplastic elastomer base material and 10-100 parts of a plasticiser comprising a mixture of a plasticising oil and a lipophilic flavouring substance which comprises menthol and/or derivatives thereof, the lipophilic flavouring substance being 5-15 wt % of the mixture. 
     An improvement provided by the invention is the enhanced oral experience provided by the pleasant flavour resulting from the presence of the lipophilic flavouring substance. 
     The oral hygiene implement preferably comprises a plastics material handle part upon which the one or more oral hygiene element is mounted. Suitable plastics materials include the plastics materials from which toothbrushes are made, typically polypropylene. 
     The oral hygiene implement is preferably a toothbrush comprising a grip handle and an integral or replaceable head with bristles extending from one surface of its head. Preferably the at least one elastomeric oral hygiene element comprises thermoplastic elastomeric lamellae extending from the opposite surface of the head. Such lamellae may be of a known shape. For example such lamellae may be in the form of strips having a length direction perpendicular to the head-handle length direction of the toothbrush, a width direction perpendicular to the said opposite surface, and a thickness direction parallel to said head-handle direction. A typical form of such lamellae is those of the known Dr.BEST™ Duo Protekt toothbrush. 
     Alternatively the oral hygiene implement may be a tongue cleaning device other than a toothbrush. An example of such a device is for example disclosed in PCT/EP06/000181 and DE-G-202 005 004291.9, relating to the “Zungen Reiniger” tongue cleaning device sold under the “DrBEST™” trade mark. 
     Thermoplastic elastomer materials are well known materials which combine the characteristics of both thermoplastics on the one hand and elastomers on the other. Numerous types of thermoplastic elastomer base material are known for use in the oral hygiene implement of this invention, for example styrene block copolymers. A suitable base material is that which is used as the base thermoplastic elastomer material used for the tongue-cleaning lamellae of the AQUAFRESH DUO CLEAN™ toothbrush marketed by the present applicant. Examples of such materials are he Thermolast K™ family of thermoplastic elastomer materials available from the supplier Gummiwerk Kraiburg GmbH &amp; Co. KG, Germany, for example the material TF 3 AAH. These are based on hydrogenated styrene block copolymers. 
     The thermoplastic elastomer material preferably has a hardness in the range ShoreA 30+/−3. 
     Preferably the thermoplastic elastomer material contains 20-80 parts of the plasticiser. The composition range of the plasticiser, i.e. 5-15 wt % of the lipophilic flavouring substance in the plasticiser mixture appears to be important in optimising the taste perceived by the user of the oral hygiene implement of this invention. A preferred proportion is 10+/−2%. For example it is typically found that if less than 5% is used little benefit in taste may be experienced, and if more than 15% is used the taste may be undesirable. 
     The term “plasticising oil” used herein is intended to encompass all oils which are capable of plasticising the thermoplastic elastomer material. The term “oil” as used herein is intended to encompass all organic liquids having a plasticising function, including paraffinic, hydrocarbon and ester-based oils. The viscosity of such oils may vary between a mobile liquid and a wax. For use in the head of a toothbrush the oil must be of a non-toxic orally acceptable type, and a suitable plasticising oil is so called medical white oil. Medical white oil is a known plasticising oil for thermoplastic elastomer materials and is preferred. Typically a medical white oil comprises a highly refined mineral oil conforming to the quality requirements of the British and US Pharmacopoeias. Typically such oils comply with the quality requirements of “Mineral Hydrocarbons in Food Regulations” 1996; (S.I.No. 1073), and United States F &amp; D. A Regulations No. 178.3620(a) and 172.878. Typically such oils have the following properties: 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 ISO 15 
                 ISO 68 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Relative Density @ 60° F. 
                 0.850 
                 0.880 
               
               
                   
                 Viscosity @ 20° C. (cS) 
                 25.0 
                 235 
               
               
                   
                 Viscosity @ 40° C. (cS) 
                 15.0 
                 69.0 
               
               
                   
                   
               
            
           
         
       
     
     Suitably the lipophilic flavouring substance comprises 70 weight % or more, preferably 80 weight % or more of menthol and/or derivatives thereof. For use in the head of a toothbrush the derivative must be of a non-toxic orally acceptable type. Many such non-toxic orally acceptable compounds derived from the menthol nucleus are known. Suitable derivatives may include esters of menthol, e.g. C 1-5  alkanoic acid esters, ether and ketone derivatives in which the hydroxyl group of the menthol nucleus is replaced by a carbonyl moiety or is cyclised into an ether, e.g. furan, moiety. Preferably the lipophilic flavouring substance comprises 40-60 weight % of menthol, preferably in mixture with 20-35 weight % of menthone, preferably in mixture with 5-8 weight % of one or more menthyl ester, particularly menthyl acetate, preferably in mixture with 1-5 weight &amp; of menthofuran. An example of such a substance is Peppermint Oil. Peppermint oil generally comprises the composition: 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Minimum 
                 Maximum 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Total menthol 
                  52 wt. % 
                  56 wt. % 
               
               
                   
                 Menthone 
                  22 wt. % 
                  30 wt. % 
               
               
                   
                 Menthyl esters 
                 5.8 wt. % 
                 7.8 wt. % 
               
               
                   
                 Menthofuran 
                 1.7 wt. % 
                 3.7 wt. % 
               
               
                   
                   
               
            
           
         
       
     
     Typically in peppermint oil the menthofuran is the (R)-(+)-isomer. A further constituent of peppermint oil is the menthol derivative (R)-(+)-pulegone. 
     In addition to being pleasant, the flavour of menthol and menthol derivatives also conveys a feeling of oral freshness, and can assist in overcoming any problem of bad breath. 
     The lipophilic flavouring substance may be admixed with the plasticising oil to form the plasticiser, and the mixture then blended with the thermoplastic elastomer. Alternatively the lipophilic flavouring substance and the plasticising oil may be blended separately with the thermoplastic elastomer. 
     The oral hygiene implement with its oral hygiene element may be made according to any of the known processes for making such an implement. A typical manufacturing process comprises co-moulding of the implement from a plastics material and the thermoplastic elastomer material. In such a process the thermoplastic elastomer material defined above for use in the invention may be co-moulded by a moulding process analogous to that used for conventional materials. An example of such a co-moulding process is disclosed in WO-A-2005/084487. 
     In a further aspect the present invention therefore provides a process for making an oral hygiene implement comprising a plastics material handle part and an oral hygiene element, comprising co-moulding the plastics material handle part and an oral hygiene element made of a thermoplastic elastomer material having a hardness in the range ShoreA 20-50 and a composition comprising 100-200 parts of the thermoplastic elastomer base material and 10-100 parts of a plasticiser comprising a mixture of a plasticising oil and a lipophilic flavouring substance which comprises menthol and/or derivatives thereof, the lipophilic flavouring substance being 5-15 wt % of the mixture. 
     The process may be otherwise generally conventional. Typically such a process comprises firstly making a plastics material part of the toothbrush in a first injection mould, then enclosing the so-made plastics material part in a second injection mould having a mould cavity which defines the shape of the elastomeric oral hygiene element, then injecting the thermoplastic elastomer material into the second mould under conditions which achieve a bond between the plastics material and the thermoplastic elastomer. Typical plastics materials are known in the art of toothbrush manufacture, e.g. the plastics materials from which the plastics material parts of the Dr.BEST™ Duo Protekt toothbrush is made and include polypropylene. 
     The oral hygiene implement of this invention is preferably provided for sale in some suitable packaging, e.g. blister packaging. It has been found that some lipophilic flavouring substances, particularly those including menthol, can adversely affect pigments used on packaging, especially blue pigments, and the invention further addresses this problem. 
     This problem is addressed by a package comprising a packaging layer having a surface on which is printed matter incorporating a pigment, and this printed matter is covered by a barrier layer comprising at least one layer each of polyvinyl alcohol and polyethylene, the barrier layer being situated between the printed matter and the oral hygiene implement. 
     Further there is provided a product comprising an oral hygiene implement as defined above, enclosed within a package comprising a packaging layer having a surface on which is printed matter incorporating a pigment, this printed matter is covered by a barrier layer comprising at least one layer each of polyvinyl alcohol and polyethylene, and this barrier layer is situated between the printed material and the oral hygiene element. 
     It is found that the interposition of such a barrier layer between the oral hygiene element and the printed matter helps to prevent adverse effects of the flavouring on typical pigments used in printed matter on packaging. 
     Suitably the packaging layer may comprise a cardboard-aluminium foil laminate, with the printed matter printed on the surface of the aluminium foil layer. Preferably the barrier layer comprises two layers of polyethylene sandwiching a layer of polyvinyl alcohol intermediate between these two layers. 
    
    
     
       The present invention will now be illustrated by way of example only with reference to the accompanying drawings. 
         FIG. 1  shows an overall side view of an oral hygiene device of this invention, being a toothbrush. 
         FIG. 2  shows an overall side view of a package for the oral hygiene device of  FIG. 1 . 
         FIG. 3  shows an enlarged cross section of the construction of part of the package of  FIG. 2   
     
    
    
     Referring to  FIG. 1  an oral hygiene implement  1  overall is shown, being a toothbrush, comprising a grip handle  2  and an integral head  3  with bristles  4  extending from one surface  5  of its head  3 . The handle  2  and head  3  are made of a known polypropylene material, e.g. Moplen EP 548 T™ used in toothbrush manufacture. 
     Elastomeric oral hygiene elements  6  are provided on head  3 , being thermoplastic elastomeric lamellae extending from the opposite surface  7  of the head  3  from which the bristles  4  extend. The lamellae  6  are identical in construction to those of the known Dr.BEST™ Duo Protekt toothbrush, i.e. extending ca. 2 mm from the surface  7 , and about 1 mm wide at their base where they meet the surface  7 . The lamellae  6  are formed integrally in one piece with a covering  8  of elastomer over the head  3 . 
     The lamellae  6  and covering  8  are made of a thermoplastic elastomer material having a hardness of ShoreA 30 comprising 100-200 parts of a thermoplastic elastomer base material, for example Thermolast K™ TF 3AAH, and 10-100 parts of plasticiser. Specifically thermoplastic elastomer materials comprising respectively 120 parts of the thermoplastic elastomer base material and 20 parts of the plasticiser; and 200 parts of the thermoplastic elastomer base material and 100 parts of the plasticiser were used. 
     In each of these compositions of the thermoplastic elastomer material the plasticiser comprises a mixture of Medical white oil complying with the quality requirements of “Mineral Hydrocarbons in Food Regulations” 1996; (S.I.No. 1073), and United States F &amp; D. A Regulations No. 178.3620(a) and 172.878, with the following properties: 
                                             ISO 15   ISO 68                                                        Relative Density @ 60° F.   0.850   0.880           Viscosity @ 20° C. (cS)   25.0   235           Viscosity @ 40° C. (cS)   15.0   69.0                        
This oil is mixed with peppermint oil of a composition:
 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Minimum 
                 Maximum 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Total menthol 
                  52 wt. % 
                  56 wt. % 
               
               
                   
                 Menthone 
                  22 wt. % 
                  30 wt. % 
               
               
                   
                 Menthyl esters 
                 5.8 wt. % 
                 7.8 wt. % 
               
               
                   
                 Menthofuran 
                 1.7 wt. % 
                 3.7 wt. % 
               
               
                   
                   
               
            
           
         
       
     
     In the mixture the peppermint oil amounts to 10 weight % of the white medical oil-peppermint oil mixture. 
     The plastics material part of the toothbrush, i.e. the handle  2  and head  3  were made by a conventional injection moulding process. This plastics material part was then enclosed in an injection mould (not shown) having a mould cavity (not shown) defining the shape of the lamellae  6 , and thermoplastic elastomer material of this composition was injection moulded to form the lamellae  6 . The procedure was exactly the same way as the known elastomer material compositions which use the same white medical oil without the peppermint oil as plasticiser, i.e. in the same way as the lamellae of the known Dr.BEST™ Duo Protekt toothbrush. This is advantageous in enabling a 1:1 replacement of the known thermoplastic elastomer material of the Dr.BEST™ Duo Protekt toothbrush with the peppermint oil containing material described above. The proportion of 10 weight % peppermint oil in the plasticiser is found to be optimal in achieving a taste that is satisfactory to consumers. 
     Referring to  FIGS. 2 and 3  a package  10  overall suitable for a toothbrush  1  above is shown. This package comprises a polyethylene terephthalate blister  11  being 250 microns thick defining a typical blister cavity  12  suitable to enclose the toothbrush  1 . The blister cavity  12  is closed by a packaging layer  13 , which comprises a cardboard  13 A-aluminium foil  13 B laminate, with the printed matter  14  printed on the surface of the aluminium foil layer  13 B. This packaging layer  13  is typically 300-400 microns thick, for example ca. 350 microns thick. This printed matter  14  is covered by a barrier layer  15  comprising two layers  15 A,  15 B of polyethylene sandwiching a layer of polyvinyl alcohol  15 C intermediate between these two layers  15 A,  15 B. The barrier layer  15  is typically 40-60 microns thick, typically ca. 50 microns thick.