TOOTHBRUSH

Description

[0001] This invention relates to oral hygiene devices.

[0002] 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.

[0003] Toothbrushes of this type are known, see for example GB-A-2 391 462 (WO-A-2004/041025) 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.

[0004] 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.

[0005] 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.

[0006] 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.

[0007] 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.

[0008] 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.

[0009] 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.

[0010] 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 the Thermolast K™ family of thermoplastic elastomer materials available from the supplier Gummiwerk Kraiburg GmbH & Co. KG, Germany, for example the material TF 3 AAH. These are based on hydrogenated styrene block copolymers.

[0011] The thermoplastic elastomer material preferably has a hardness in the range ShoreA 30 +/- 3.

[0012] 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.

[0013] 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 & D. A Regulations No. 178.3620(a) and 172.878. Typically such oils have the following properties:

ISO 15ISO 68

Relative Density @ 60°F	0.850	0.880
Viscosity @ 20°C (cS)	25.0	235
Viscosity @ 40°C (cS)	15.0	69.0

[0014] 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 % 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.%

[0015] Typically in peppermint oil the menthofuran is the (R) - (+) - isomer. A further constituent of peppermint oil is the menthol derivative (R) - (+) - pulegone.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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 he 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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

[0027] 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.

[0028] 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. 2mm from the surface 7, and about 1mm 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.

[0029] 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.

[0030] 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 & D. A Regulations No. 178.3620(a) and 172.878, with the following properties:

ISO 15ISO 68

Relative Density @ 60°F	0.850	0.880
Viscosity @ 20°C (cS)	25.0	235
Viscosity @ 40°C (cS)	15.0	69.0

[0031] 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.%

[0032] In the mixture the peppermint oil amounts to 10 weight % of the white medical oil - peppermint oil mixture.

[0033] 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.

[0034] 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 13A - aluminium foil 13B laminate, with the printed matter 14 printed on the surface of the aluminium foil layer 13B. 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 15A, 15B of polyethylene sandwiching a layer of polyvinyl alcohol 15C intermediate between these two layers 15A, 15B. The barrier layer 15 is typically 40-60 microns thick, typically ca. 50 microns thick.

Claims

1. An oral hygiene implement, having at least one elastomeric oral hygiene element made of a thermoplastic elastomer material having a hardness in the range ShoreA 20-50 characterized in that the thermoplastic elastomer material has 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.

2. An oral hygiene implement according to claim 1 being a toothbrush comprising a grip handle and an integral or replaceable head with bristles extending from one surface of its head, and the at least one elastomeric oral hygiene element comprises thermoplastic elastomeric lamellae extending from the opposite surface of the head.

3. An oral hygiene implement according to claim 1 or claim 2 wherein the plasticizing oil comprises medical white oil.

4. An oral hygiene implement according to claim 1, 2 or 3 wherein the lipophilic flavouring substance comprises 10 +/- 2% of the plasticiser.

5. An oral hygiene implement according to any one of claims 1 to 4 wherein the lipophilic flavouring substance comprises 70 weight% or more of menthol and/or one or more derivative thereof.

6. An oral hygiene implement according to claim 5 wherein the lipophilic flavouring substance comprises 40 - 60 weight % of menthol, in mixture with 20 - 35 weight % of menthone, 5 - 8 weight % of one or more menthyl ester particularly menthyl acetate, and 1 - 5 weight % of menthofuran.

7. An oral hygiene implement according to claim 6 wherein the lipophilic flavouring substance 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.%

8. An oral hygiene implement (1) according to any one of the preceding claims wherein the lipophilic flavouring substance comprises peppermint oil.

9. A process for making an oral hygiene implement (1) comprising a plastics material handle part (2) and an oral hygiene element (6), comprising co-moulding the plastics material handle part (2) and an oral hygiene element (6) 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.

10. An oral hygiene implement (1) according to any one of claims 1 to 8, characterised in that the implement (1) is provided in packaging comprising a packaging layer (13) having a surface on which is printed matter (14) incorporating a pigment, and this printed matter is covered by a barrier layer (15) comprising at least one layer each of polyvinyl alcohol (15C) and polyethylene (15A, 15B), the barrier layer (15) being situated between the printed matter (14) and the oral hygiene implement (1).

11. An oral hygiene implement (1) according to claim 10 wherein the barrier layer (15) comprises two layers (15A, 15B) of polyethylene sandwiching a layer of polyvinyl alcohol (15C) intermediate between these two layers (15A, 15B) of polyethylene.

12. An oral hygiene implement (1) according to claim 10 or 11 wherein the barrier layer (15) has a thickness 40 - 60 microns.

Ansprüche

1. Mundhygienegerät (1) mit zumindest einem elastomeren Mundhygieneelement (6), hergestellt aus einem thermoplastischen Elastomermaterial mit einer Härte im Bereich ShoreA 20-50, dadurch gekennzeichnet, dass das thermoplastische Elastomermaterial eine Zusammensetzung aufweist, umfassend 100 - 200 Teile eines thermoplastischen Elastomergrundmaterials und 10 - 100 Teile eines Weichmachers, umfassend eine Mischung eines Weichmacheröls und einer lipophilen Aromasubstanz, die Menthol und/oder Derivate davon umfasst, wobei die lipophile Aromasubstanz 5-15 Gew.% des Gemischs ausmacht.

2. Mundhygienegerät (1) gemäß Anspruch 1, das eine Zahnbürste ist, umfassend einen Griff (2) und einen fest eingebauten oder austauschbaren Kopf (3) mit Borsten (4), die sich von einer Oberfläche (5) seines Kopfes erstrecken, und das zumindest eine elastomere Mundhygieneelement (6) thermoplastische, elastomere Lamellen umfasst, die sich von der gegenüberliegenden Oberfläche (7) des Kopfes erstrecken.

3. Mundhygienegerät (1) gemäß Anspruch 1 oder Anspruch 2, wobei das Weichmacheröl medizinisches Weißöl umfasst.

4. Mundhygienegerät (1) gemäß Anspruch 1, 2 oder 3, wobei die lipophile Aromasubstanz 10 +/- 2 % des Weichmachers umfasst.

5. Mundhygienegerät (1) gemäß einem der Ansprüche 1 bis 4, wobei die lipophile Aromasubstanz 70 Gew.% Menthol oder mehr und/oder ein oder mehrere Derivate davon umfasst.

6. Mundhygienegerät (1) gemäß Anspruch 5, wobei die lipophile Aromasubstanz 40 - 60 Gew.% Menthol, im Gemisch mit 20 - 35 Gew.% Menthon, 5 - 8 Gew.% ein oder mehrerer Menthylester, insbesondere Menthylacetat, und 1 - 5 Gew. % Menthofuran, umfasst.

7. Mundhygienegerät (1) gemäß Anspruch 6, wobei die lipophile Aromasubstanz die folgende Zusammensetzung umfasst:

	Minimum	Maximum
Gesamtes Menthol	52 Gew.%	56 Gew.%
Menthon	22 Gew.%	30 Gew.%
Menthylester	5,8 Gew.%	7,8 Gew.%
Menthofuran	1,7 Gew.%	3,7 Gew.%.

8. Mundhygienegerät (1) gemäß einem der vorhergehenden Ansprüche, wobei die lipophile Aromasubstanz Pfefferminzöl umfasst.

9. Verfahren zur Herstellung eines Mundhygienegeräts (1), umfassend ein Griffteil (2) aus Kunststoffmaterial und ein Mundhygieneelement (6), umfassend Co-Formung des Griffteils (2) aus Kunststoffmaterial und eines Mundhygieneelements (6), hergestellt aus einem thermoplastischen Elastomermaterial mit einer Härte im Bereich ShoreA 20-50, und einer Zusammensetzung, umfassend;
100 - 200 Teile eines thermoplastischen Elastomergrundmaterials und 10 - 100 Teile eines Weichmachers, umfassend eine Mischung eines Weichmacheröls und einer lipophilen Aromasubstanz, die Menthol und/oder Derivate davon umfasst, wobei die lipophile Aromasubstanz 5-15 Gew.% der Mischung ausmacht.

10. Mundhygienegerät (1) gemäß einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, dass das Gerät (1) in einer Verpackung bereitgestellt wird, umfassend eine Verpackungsschicht (13) mit einer Oberfläche, auf die ein Pigment enthaltendes Material (14) gedruckt wird, und dieses gedruckte Material durch eine Barriereschicht (15) bedeckt wird, umfassend zumindest eine Schicht von jeweils Polyvinylalkohol (15C) und Polyethylen (15A, 15B), wobei die Barriereschicht (15) zwischen dem gedruckten Material (14) und dem Mundhygienegerät (1) liegt.

11. Mundhygienegerät (1) gemäß Anspruch 10, wobei die Barriereschicht (15) zwei Polyethylenschichten (15A, 15B) umfasst, die eine Polyvinylalkoholschicht (15C), die zwischen diesen zwei Polyethylenschichten (15A, 15B) liegt, zusammenpresst.

12. Mundhygienegerät (1) gemäß Anspruch 10 oder 11, wobei die Barriereschicht (15) eine Dicke von 40 - 60 µm aufweist.

Revendications

1. Instrument d'hygiène buccale (1), ayant au moins un élément d'hygiène buccale élastomère (6) constitué d'un matériau élastomère thermoplastique ayant une dureté dans la plage ShoreA 20-50, caractérisé en ce que le matériau élastomère thermoplastique a une composition comprenant 100 - 200 parties d'un matériau de base élastomère thermoplastique et 10 - 100 parties d'un plastifiant comprenant un mélange d'une huile plastifiante et d'une substance aromatisante lipophile qui comprend du menthol et/ou des dérivés de celui-ci, la substance aromatisante lipophile représentant 5-15 % en poids du mélange.

2. Instrument d'hygiène buccale (1) selon la revendication 1 étant une brosse à dents comprenant un manche de préhension (2) et une tête intégrée ou remplaçable (3) avec des poils (4) s'étendant à partir d'une surface (5) de sa tête, et l'au moins un élément d'hygiène buccale élastomère (6) comprend des lamelles élastomères thermoplastiques s'étendant à partir de la surface opposée (7) de la tête.

3. Instrument d'hygiène buccale (1) selon la revendication 1 ou la revendication 2, dans lequel l'huile plastifiante comprend de l'huile blanche médicale.

4. Instrument d'hygiène buccale (1) selon la revendication 1, 2 ou 3, dans lequel la substance aromatisante lipophile comprend 10 +/- 2 % du plastifiant.

5. Instrument d'hygiène buccale (1) selon l'une quelconque des revendications 1 à 4, dans lequel la substance aromatisante lipophile comprend 70 % en poids ou plus de menthol et/ou un ou plusieurs dérivés de celui-ci.

6. Instrument d'hygiène buccale (1) selon la revendication 5, dans lequel la substance aromatisante lipophile comprend 40 - 60 % en poids de menthol, en mélange avec 20 - 35 % en poids de menthone, 5 - 8 % en poids d'un ou plusieurs esters de menthyle, en particulier, acétates de menthyle, et 1 - 5 % en poids de menthofurane.

7. Instrument d'hygiène buccale (1) selon la revendication 6, dans lequel la substance aromatisante lipophile comprend la composition :

	Minimum	Maximum
Total menthol	52 % en poids	56 % en poids
Menthone	22 % en poids	30 % en poids
esters de menthyle	5,8 % en poids	7,8 % en poids
Menthofurane	1,7 % en poids	3,7 % en poids

8. Instrument d'hygiène buccale (1) selon l'une quelconque des revendications précédentes, dans lequel la substance aromatisante lipophile comprend de l'huile de menthe poivrée.

9. Procédé de fabrication d'un instrument d'hygiène buccale (1) comprenant une partie de manche en plastique (2) et un élément d'hygiène buccale (6), comprenant le co-moulage de la partie de manche en plastique (2) et un élément d'hygiène buccale (6) constitué d'un matériau élastomère thermoplastique ayant une dureté dans la plage ShoreA 20-50 et une composition comprenant :

100 - 200 parties d'un matériau de base élastomère thermoplastique et 10 - 100 parties d'un plastifiant comprenant un mélange d'une huile plastifiante et d'une substance aromatisante lipophile qui comprend du menthol et/ou des dérivés de celui-ci, la substance aromatisante lipophile représentante 5-15 % en poids du mélange.

10. Instrument d'hygiène buccale (1) selon l'une quelconque des revendications 1 à 8, caractérisé en ce que l'instrument (1) est prévu dans un conditionnement comprenant une couche de conditionnement (13) ayant une surface sur laquelle se trouve une matière imprimée (14) incorporant un pigment, et cette matière imprimée est couverte par une couche de barrière (15) comprenant au moins une couche chacune d'alcool polyvinylique (15C) et de polyéthylène (15A, 15B), la couche de barrière (15) étant située entre la matière imprimée (14) et l'instrument d'hygiène buccale (1).

11. Instrument d'hygiène buccale (1) selon la revendication 10, dans lequel la couche de barrière (15) comprend deux couches (15A, 15B) de polyéthylène prenant en sandwich une couche d'alcool polyvinylique (15C) intermédiaire entre ces deux couches (15A, 15B) de polyéthylène.

12. Instrument d'hygiène buccale (1) selon la revendication 10 ou 11, dans lequel la couche de barrière (15) a une épaisseur de 40 - 60 microns.

Drawing