EP4329556A1

EP4329556A1 - Disposable toothbrush

Info

Publication number: EP4329556A1
Application number: EP21735346.5A
Authority: EP
Inventors: Amy Ruth MURPHY
Original assignee: Threezero 000 Ltd
Current assignee: Threezero 000 Ltd
Priority date: 2021-04-30
Filing date: 2021-04-30
Publication date: 2024-03-06
Also published as: WO2022229586A1

Abstract

A toothbrush comprising a handle, a head formation and bristles on the head formation, wherein both the head formation and bristles are provided as a unitary mass of a biodegradable polymer material.

Description

Disposable Toothbrush

This invention concerns toothbrushes and more particularly single-use and/or disposable toothbrushes.

It is generally more economical and environmentally friendly to reuse toothbrushes a significant number of times before disposal. However there are a variety of circumstances in which a disposable toothbrush is needed. One such scenario is on-board a passenger vehicle, such as bus/coach, train, boat, aircraft or the like, where a vehicle operator may provide a toothbrush to a passenger. Other scenarios include patients in care within a medical facility or people spending a period of time in remote locations, e.g. workers on-site or military personnel in the field. Conventional disposable toothbrushes are in many ways similar to normal, multiuse toothbrushes and comprise nylon or polyester bristles held on a plastics handle, such as copolyester, polypropylene or polyethylene. Where a multiuse toothbrush may also have softer grip material on the handle, disposable toothbrushes often do not. Conventional disposable toothbrushes may simply be seen as cheaper variants of multi-use toothbrushes. These products are not therefore classed as being biodegradable and will take hundreds of years to decompose. There is ongoing effort to reduce the adoption of such plastic items as disposable or single-use products. Some toothbrush manufacturers are coordinating toothbrush recycling to lessen the impact on the environment. However disposable toothbrushes are used in an ad-hoc fashion and so coordination of collection of such toothbrushes is not practical in all scenarios. Furthermore, handling of a used toothbrush represents a source of potential viral or bacterial cross-contamination.

When a disposable toothbrush is also provided with a single-use tube of toothpaste, this increases the negative environmental impacts described above. European Patent EP2459110 B1 describes a dentifrice composition that can be provided in a gelatin capsule format within the bristles of a toothbrush.

Over recent years, some alternatives to conventional toothbrushes have also been proposed in order to address the environmental impact of conventional toothbrushes. Bamboo toothbrushes have attracted attention as a more sustainable and biodegradable solution. However the majority of bamboo toothbrushes still have conventional, i.e. nylon, bristles. The product is therefore only partially biodegradable, meaning that the nylon bristles still pose an ongoing concern long after the handle has broken down. Furthermore the bristles are not readily removable from the handle by the end user meaning that the product must be disposed of as a whole, i.e. without separation of biodegradable and non- biodegradable parts.

Some natural bristles have been adopted in an effort to provide a fully biodegradable and/or organic toothbrush. However natural bristles typically take the form of coarse hair, such as boar hair, and do not provide the same brushing experience as synthetic bristles. The use of animal derived products may also make them unsuitable for use by those who adhere to specific religious or cultural conventions.

It is an aim of the present invention to overcome or mitigate one or more of the above identified problems. It may be considered an additional or alternative aim to provide a biodegradable toothbrush that can be disposed of in a more convenient manner.

According to a first aspect of the present invention there is provided a toothbrush in which the handle and/or bristles are formed from a biodegradable and/or water soluble polymer.

Both the handle and bristles may comprise, or be formed from, the same material. The handle and bristles may comprise a unitary, uniform and/or continuous mass of said material. The toothbrush may be entirely formed of the same material.

The polymer/material may comprise polyvinyl alcohol.

The toothbrush may break down in the presence of water. The toothbrush may break down in the presence of water within 7 days, 5 days or less. The toothbrush may break down in the presence of water within 72 hours, 48 hours, 24 hours or 12 hours.

The toothbrush or article may comprise a dentifrice material within, amongst or in- between the bristles. The dentifrice material may be surrounded by the bristles. The bristles may be provided in an annular array around the dentifrice material. A mass or bead of the dentifrice material may be provided within and/or surrounded by the bristles. The dentifrice may comprise an organic paste.

According to a second aspect, there is provided an oral hygiene article comprising the toothbrush of the first aspect sealed inside a water impervious wrapper.

According to a third aspect, there is provided a toothbrush having a head portion and bristles moulded from the same material, such that the bristles and head portion are unitary, uniform and/or continuous. The toothbrush may be devoid of an interface or join between the bristles and head portion. The outer surface of the bristles and head portion may be continuous.

The bristles may comprise protrusions or projections from the head portion. The bristles may comprise raised projections, fingers or peaks of the head portion.

Each bristle may comprise a discrete, elongate/slender projection having a height dimension that is a plurality of time larger than its width/diameter dimension. The bristles may be generally cylindrical. The bristles may be slightly tapered towards and distal end and/or may be rounded at a distal end.

The toothbrush may comprise a handle. The handle may comprise the head portion. The head portion may depend from the handle. The head portion may be integral with the handle. The handle may be moulded from the same material as the head portion, i.e. forming a uniform, unitary and/or continuous body.

The handle/head and bristles may share a common outer surface, which may be continuous. The handle/head and bristles may be indivisible. The handle/head and bristles may consist of the same material.

According to a further aspect, there is provided a toothbrush having a handle and bristles moulded from the same material, such that the bristles and handle are unitary, uniform and/or continuous.

The handle or head portion may comprise a formation for receiving a volume of dentifrice material. The formation may be provided within the bristles. The formation may comprise a raised wall.

The formation may comprise an upstanding annulus. The formation may comprise a dome, e.g. with the dentifrice contained within the dome.

The formation may comprise a frangible layer, e.g. a cover layer. The dentifrice may be enclosed behind a cover layer, e.g. within the material of the toothbrush. The layer may be frangible to release/expose the dentifrice.

The toothbrush may comprise a closure, e.g. in a head portion of the toothbrush. The closure may be on the opposing side of the toothbrush from the bristles, e.g. a rear side of the handle or head portion. The closure may close/seal against a receiving formation or recess in the toothbrush handle/head portion. The closure may comprise a locating formation and/or ring seal about its periphery. The toothbrush may comprise a removable cap, e.g. covering the bristles. The removable cap may sealingly engage the toothbrush handle/head portion. The dentifrice may be provided inside the cap when engaged over the bristles. The cap may comprise a ring seal or lip in its inside surface. The cap may comprise a grip or tab portion to aid removal.

The toothbrush may comprise a frangible/removable portion, e.g. within the handle. The removable portion may be encircled or surrounded by the handle. The removable portion may have reduced wall thickness, e.g. being generally flat or planar in form. The removable portion may comprise a grip portion and/or tip portion. The tip portion may be tapered and/or thinner than the grip portion. The tip may terminate at a distal point or apex.

The grip portion of the removable/frangible portion may comprise a grip portion of the toothbrush handle when attached.

The removable/frangible portion may comprise a toothpick.

The removable/frangible portion may be attached to the toothbrush handle by one or more tab.

According to a further aspect of the invention, there is provided a toothbrush comprising a handle and a head formation having bristles, wherein the toothbrush comprises a detachable and/or frangible portion, said detachable portion comprising a toothpick.

The toothbrush may be a disposable toothbrush.

The detachable portion may be provided within the handle and may be recessed within the handle.

The detachable portion and handle may be integral, unitary and/or commonly formed by a moulding process. The detachable portion may be attached to the handle by one or more frangible tab. The one or more frangible tab may be integrally formed with the handle and/or detachable portion, e.g. as a bridge therebetween.

According to a further aspect, there is provided a method of manufacture of a toothbrush according to any preceding aspect. The method may comprise moulding the toothbrush handle and/or head portion commonly with the bristles, e.g. using the same material. The bristles and head portion/handle may be formed using a single moulding shot.

The mould cavity may comprise a plurality of recesses/depressions in which the bristles are formed. Each bristle recess/depression may be individually vented.

The mould cavity may comprise an insert on the rear side of the toothbrush head.

The cavity may comprise a formation shaped to define a recess for receiving a dentifrice in the toothbrush head.

The method may comprise applying a dentifrice to the toothbrush head, e.g. within the bristles and/or formation formed during the moulding process. The method may comprise applying a closure/cap to seal the dentifrice on the toothbrush head.

The method may comprise providing the toothbrush with the dentifrice in package/wrapper, which may be waterproof.

Any optional features defined in relation to any one aspect of the invention may be applied to any other aspect where practicable.

Workable embodiments of the invention are described in further detail below by way of example only with reference to the accompanying drawings, of which:

Figure 1 shows a three-dimensional view from above of a toothbrush according to an aspect of the invention. Figure 2 shows rear a side views of the toothbrush of figure 1.

Figure 3 shows a closeup three-dimensional view of the head of the toothbrush of figure 1.

Figure 4 shows a three-dimensional view from above of a toothbrush and cap assembly according to the invention.

Figure 5 shows side and front views of the toothbrush assembly of figure 4 with the cap attached.

Figure 6 shows a closeup three-dimensional view of the head of the toothbrush of figure 4 from the rear.

Figure 7 shows a three-dimensional view from above of a toothbrush according to a further aspect of the invention.

Figure 8 shows an exploded three-dimensional view from the rear of the toothbrush of figure 7.

Figure 9 shows a closeup exploded view of the toothbrush head of figure 7.

Figure 10 shows a view from the rear of the arrangement of figure 9.

Figure 11 shows a schematic side view of mould elements for manufacture of a toothbrush.

Turning firstly to figures 1-3, there is shown a toothbrush 10 comprising a handle body 12 having a handle/grip portion 14 and a head portion 16. The handle body 12 is elongate and the grip portion and head portions of the body are

The grip portion 14 comprises a surface texture or pattern of protrusions/ridges 18 over a surface area of the handle intended to be held in use. In this example, a series of ridges 18 are provided at spaced locations along the length of the grip portion 14. Different arrays or patterns of ridges could be used. The ridges 18 are arch like in form in this example but could otherwise be described as crescent or chevron shaped. Different shapes of ridge could be used in other examples.

A perimeter or outline 20 of the grip portion is defined in the handle body 12. The perimeter is defined by a groove or lip in the material of the handle body running around the grip portion 14. The grip portion may be raised or delineated from the remainder of the handle body 12 by the outline 20. The grip portion 14 and remainder of the handle body are formed of the same material as will be described below. However the surface of the grip portion may be raised, textured, patterned or otherwise delineated form the remainder of the handle portion, e.g. by moulded surface features thereof.

The handle body 12 comprises a detachable portion 22 within the grip region 14 in this example. In this regard the handle body 12 comprises a frangible, removable or actuatable member. The detachable portion 22 is contained within the perimeter of the grip portion 14. The detachable portion may be entirely contained within the width, length and/or depth of the grip portion 14. The detachable portion 22 in this example has reduced wall thickness relative to the remainder of the grip portion 14, e.g. such that the portion 22 is generally flat or planar in form. The detachable portion 22 is thus sunken or recessed relative to the surface of the grip portion.

The detachable portion 22 is contained within an opening 24 in the handle body 12, i.e. within the grip portion 14 thereof. The opening 24 is elongate and curved in plan, e.g. akin to a lozenge or oblong shape. The opening encloses the detachable portion 22 in two dimensions.

The detachable portion 22 is attached to the handle body, e.g. the edge of the opening 24, via one or more tab 26. A plurality of tabs 26 are provided in this example on opposing sides of the detachable portion 22. The detachable portion is thus seated/held in the opening 24 as shown in figure 1 but is removable therefrom when required by a user. The tab(s) 26 are moulded as an integral part of the handle body 12 and detachable portion 22. The detachable portion 22 and handle body 12 are unitary or integrated as shown as a single mass of material through the tabs, which serve as frangible bridges from the handle body 12 to the detachable portion 22.

The detachable portion 22 provides a toothpick or flossing tool, i.e. a member that can be used to clean or dislodge debris/matter from between a user’s teeth. The detachable portion may be of reduced wall thickness allowing it to be partially inserted between teeth when detached form the handle body 12. The detachable portion 22 may comprise a main body region and a tip portion 28. The main body of the detachable portion 22 may provide a grip portion of the toothpick. The surface texture and/or pattern of ridges may emulate or match the surface features of the grip portion 14 of the handle body 12. The main body of the detachable portion 22 may be generally flat/planar so as to be gripped between a user’s finger and thumb in use.

The tip portion 28 has reduced width and/or wall thickness compared to the remainder of the detachable portion 22. The tip portion 28 may be tapered in width and/or wall thickness towards a distal end or tip thereof. The tip portion 28 is pointed in this example.

The detachable portion 22 may be curved in plan, e.g. being teardrop or generally elliptical in shape, save for the pointed tip. The detachable portion may be described as being ‘surfboard-like’ in form.

Any of the features of the handle/grip portion 14 described above with respect to an upper side of the toothbrush handle may also be applied to the rear side of the toothbrush. In the example shown in figure 2, the perimeter feature is labelled 20a but the rear side is devoid of grip formations 12.

The toothbrush 10 comprises bristles 30. The bristles depend from the head portion16. The bristles 30 are integrally formed with the head portion 16. That is to say, the bristles 30 take the form of a monolithic or unitary/continuous structure with the head portion 16. The bristles are not separately attached to the head portion but are instead a continuation of the head portion with no interface between the head portion and bristles. In this example, the handle/grip portion 14 and head portion 16 are also unitarily formed, e.g. such that the entire toothbrush, including bristles, is a monolithic, unitary and/or continuous body (i.e. a single mass of the same material). However in other examples, the grip portion 14 could be a separate component that is attached the unitary head portion 16. In this regard, the head portion could be integral with the bristles but the grip portion may not, e.g. with the grip portion 14 being formed of a different biodegradable material form the head and bristles.

In the example of figures 1-4, the detachable portion 22 is also unitarily formed with the grip portion 14, head portion 16 and bristles 13.

An arrangement of greater than or equal to thirty, forty or fifty bristles is provided. The bristles have a width/diameter dimension of less than 1 mm, e.g. less than 0.8mm, 0.6mm or 0.5mm. The bristles may have a width/diameter dimension of greater than or equal to 0.2mm, 0.3mm or 0.4mm.,

The bristles are spaced apart by a distance that is of an order of magnitude akin to their width. The spacing may be 1 -5 times the bristle width, e.g. two or three times the bristle width. This differs from conventional bristles, where clusters of tightly packed bristles are conventionally provided.

The bristles are generally elongate and/or cylindrical in form. The height/length dimension of the bristles is typically less than 20mm, e.g. between 5 and 15 mm. The height of the bristles may be multiple times greater than the bristle width, e.g. at least five or ten times greater.

The bristles may be filleted at their base, e.g. being wider in plan and/or curved outwardly at the base.

The bristles may be profiled/rounded at their tips, i.e. their distal ends. This is unlike conventional bristles that are cut to length.

Turning to figure 4, the head portion 16 is shown in further detail.

An array of bristles 30 is provided circumferentially around a central formation 32 of the head portion 16. The central formation 32 depends upwardly from the head portion 16, e.g. in the same direction as the bristles, and is unitary therewith. The central formation takes the form of a wall, e.g. an annular wall. That is lower in height than the bristles 30.

The central formation 32 may be less than or equal to half the height of the bristles 30. The central formation may be greater than Vs or ¼ of the height of the bristles. The central formation/wall may be approximately 3 of the height of the bristles.

The central formation this example takes the form of a castellated wall.

The central formation is annular in form, e.g. defining a central/internal space or cavity 34 that is surrounded by the wall and, in turn, by the bristles 30. The cavity 34 is open in an upwardly facing direction in this example.

The cavity 34 defines a space in which a dentifrice material can be provided on the toothbrush head portion 16. The dentifrice material can thus be securely provided amongst the bristles in a manner that is exposed for release in a user’s mouth when brushing their teeth.

The dentifrice itself is not shown in the figures. A conventional dentifrice may be used. Preferably an organic dentifrice is provided. The skilled person will appreciate that various dentifrice materials and compositions could be considered. The dentifrice preferably does not comprise any excess or free moisture (i.e. water). The dentifrice could comprise a paste, gel or dry powder.

Preferably the dentifrice is provided on the head portion prior to packaging/assembly of the toothbrush. Thus the toothbrush comprises the dentifrice as a packaged article that can be shipped, transported, sold, etc in a form that is ready for use, e.g. without requiring and additional items for use.

Turning now to figures 4 to 6, there is shown a further example of a toothbrush, provided as a capped toothbrush assembly. The assembly comprises the toothbrush 10 of figures 1-3 and a removable cap 36 for covering the bristles of the head portion 16. The cap 36 also covers any dentifrice located on the head portion 16, e.g. amongst the bristles.

The cap is formed from the same material as the head portion 16, bristles 30 and/or grip portion 14 of the handle body.

The cap 36 comprises a peripheral/side wall and an end face, closing one side of the cap, whereas the other side of the cap remains open, i.e. to receive the head portion 16.

The cap is shaped to fit closely/tightly around the perimeter of the head portion 16, e.g. around the perimeter of the array or bristles. The cap is attachable/removable from above, i.e. over the bristles.

The head portion may comprise a formation 38, such as a lip, shoulder or groove around its perimeter for receiving the cap 36. Additionally or alternatively, the cap 36 may comprise a formation around its internal surface to fit with head portion. The tight fit between the head portion perimeter and cap may form a seal, e.g. a water tight or air tight seal.

The cap 36 is shown in greater detail in figure 5 and comprises a protrusion 40 on each side of the cap to allow removal of the cap from the head portion 16 for use of the toothbrush. The protrusion 40 takes the form of a lip, flange or tab, acting as a grip formation so that a user can pull the cap away from the head portion 16.

The cap 36 in this example also comprises an internal formation 42 for connection/alignment with the upstanding formation 32 of the head portion 16. The formation 42 may depend downwardly from the lid of the cap and may engage with the upstanding formation 32 when the cap is correctly fitted on the head portion 16. The internal formation may comprise an arm, tab or internal wall. The internal formation could be barbed or similar to provide a latching arrangement, e.g. a click-fit. The cap 36 also comprises a central depression 44, e.g. aligning with the upstanding formation 32 in plan when the cap and head portion 16 are attached. The base of the depression 44 may contact or engage with the upstanding formation 32 when the cap 36 is applied to the head portion 16.

In the example of figures 5-7, the dentifrice is captured/enclosed on the toothbrush head portion by use of a cap 36. In that condition the toothbrush is maintained in a ready to use format. The cap is removed to expose the dentifrice for brushing. The cap can be replaced after use so that the toothbrush is safe to handle once rinsed, e.g. presenting a reduced cross-contamination risk.

Turning now to figures 8-10, there is shown a further example in which the dentifrice can be enclosed on the toothbrush head portion itself, e.g. without the need for a removable cap. The toothbrush 10a in figures 8-10 is as disclosed above, save for the differing features detailed below.

The head portion 16a of toothbrush 10a has a closed formation 32a for retaining a dentifrice material, instead of the open formation 32 of figures 1-8. The closed formation 32a comprises a dome-like shape so as to enclose the dentifrice beneath it. The formation 32a comprises a thin layer or skin of the same material that is used to form the toothbrush. The formation 32a may therefore be integrally moulded with the toothbrush.

The height of formation 32a is lower than the height of the bristles 30a, e.g. akin to formation 32 described above.

On a rear side of the head portion 16a, i.e. the side of the head portion facing away from the bristles 30a, there is provided an opening 46 as shown in figures 8 and 10. The opening 46 leads into an internal cavity inside the head portion 16a behind the formation 32a. Thus the head cavity is hollow and can receive the dentifrice therein.

A plug member 48 is used to close the internal cavity with the dentifrice therein. The plug member 48 is shaped to be received with a close/tight fit in the opening 46. The plug member is shaped to correspond to the shape of the opening 46. The outer surface of the plug member and/or inner surface of the opening may comprise a sealing formation, such as a ridge, groove, lip or the like.

Unlike the cap 36, the plug member 48 is not intended to be removed once inserted. As such the cooperation between the plug member and opening 46 may be non-return or permanent, e.g. comprising an interference or snap fit.

The opening and/or plug may comprise a step or shoulder formation to cooperate with the opposing component.

As shown in figures 9 and 10, the head portion 16 and plug 48 may comprise corresponding alignment formations. In this example, the head portion comprises a recess 50 adjacent the opening 46 and the plug comprises a spigot 52 arranged to be received in the recess. The spigot is spaced/offset from the sealing wall of the plug and the recess is correspondingly offset from the opening 46. The recess 50 is formed in a step formation in the head portion 16 that is offset in height from the opening 46.

The plug 46 comprises a central pedestal 54 arranged to extend into the cavity to beneath the formation 32a. The protrusion partially fills the cavity and thereby presents a bead or body of dentifrice material immediately beneath the formation 32a, e.g. substantially filling the remaining void of the cavity.

The dentifrice may be provided on the pedestal or else inside the cavity prior to insertion of the plug in the rear opening 46 of the head portion 16. The dentifrice is thus presented and trapped/sealed behind the formation 32a ready for use. The plug may create a water tight and/or air tight seal with the opening 46 once in place. In this manner, the dentifrice can be sealed in the head portion itself without the need for a separate cap.

In use, the user can simply start brushing their teeth with the brush and the thin wall of the formation 32a will yield to release the dentifrice within the user’s mouth.

The above toothbrush examples are formed from a water-soluble and/or biodegradable polymer. The polymer may be an oil based/derived water soluble polymer, such as a synthetic resin. The polymer used in this example comprises polyvinyl alcohol (PVOH-PVA-PVAI. In other examples, the polymer could be a starch based (i.e. non-oil based) polymer, such as polylactic acid (PLA), e.g. a PLA/starch blend.

Whilst water soluble polymers have been developed for other applications, they have not been previously considered for toothbrushes. The water soluble property of the material makes it counterintuitive to use for toothbrushes. However it has been found that the moulding of the polymer into a solid body with integral bristles has sufficient structural integrity for a single-use oral hygiene article even whilst wet.

The moulded material used to form the toothbrush may be tailored to substantially maintain its structural integrity in the presence of water for at least 5, 10 or 15 minutes. The degrading of the material may begin immediately on contact with water, or with a short delay, but may be at a rate sufficient for the bristles to remain intact for at least said period. The bristles may degrade such that their structural integrity is compromised (e.g. irreversibly degrades) in the presence of water within a period in the region of about one hour to one day.

The structural integrity of the toothbrush as a whole may irreversible degrade within a period a period of between about one hour and one week. The solid toothbrush material may degrade to produce a liquid and gas in the presence of water and/or microorganisms. In some examples, the material could be water soluble.

The structural integrity of the solid mass of PVOH in the form of a toothbrush as disclosed herein will remain sufficiently intact for at least 5-10 minutes of use.

The PVOH or other biodegradable polymer may be modified to get the right balance of flexibity/stiffness and/or biodegradability. This may be achieved using modifiers/additives to the polymer at master batch level, i.e. prior to moulding. Additionally or alternatively it is possible with the use of additives/modifiers to vary the polymer material’s trigger time (i.e. the delay in initiation or onset of degradation) and/or longevity (i.e. the rate of degradation through the mass of the polymer material).

PVOH is safe for ingestion by humans and animals. Furthermore, as the structure breaks down in the presence of water and microorganisms/bacteria, carbon dioxide and water are formed. Thus the entire brush can be safely disposed of after use by placing in composting, or landfill. In the presence of water and bacteria, the material will break down in a matter of hours or days. Furthermore, PVOH will biodegrade in ambient conditions and as such does not require a temperature or bacteria controlled industrial composting environment. That is to say the toothbrush is ‘home compostable’.

Turning now to figure 11 , there is shown a schematic example of mould features used during the manufacture of the toothbrush 10 or 10a described herein. The toothbrush can be injection moulded by filling a mould cavity with the molten polymer material at elevated temperature. The mould cavity is provided in two halves of a mould tool and is cooled in a conventional manner so that the polymer solidifies in the mould and the opposing tool halves opened to eject the moulded toothbrush. In figure 11 there is shown an insert member 56 for the core of the mould tool cavity in which the toothbrush head and bristles are formed. The insert member 56 provides a plurality of venting channels 58 allowing air to escape the cavity as the molten material enters.

The mould cavity comprises individual slender recesses for each bristle formation 30 of the toothbrush head. Each recess of the tool has an associated vent channel 58. Thus each bristle recess of the cavity is individually vented. In this regard, it will be appreciated that the bristle recesses in the cavity each have a width dimension that is equal to the diameter of the bristles formed therein. The vent channels 58 extend from the distal ends of the recesses and may have reduced width/diameter. Thus the surface tension in the molten polymer allows the polymer material to enter and will the recesses, e.g. allowing air to escape via the channels 58, but the surface tension prevents entry of the molten material into the narrower vent channels themselves.

In this way the distal ends of the bristles are profiled according to the profile of the ends of the recesses in the cavity and may be curved, rounded or tapered as required to provide a desired feel and cleaning action when the toothbrush is used.

The vent channels may comprise a valve or closure 60 to selectively open/close the vent channels 58 at a desired point of the moulding process. The vent channels 58 may be closed at the point when the mould cavity has been filled, e.g. substantially or completely, with molten material.

The insert 56 may be provided as a venting block formation within the mould tool.

A different mould insert 62 may be provided for a different function in the moulding process. The insert 62 may be removable or interchangeable to define optional features in the moulded toothbrush. In this manner, different inserts 62 can be used to define the different features of the embodiments 10 and 10a described herein. The insert 62 may be provided on the part of the mould cavity defining the rear of the toothbrush head. For the embodiment 10, the insert 62 may define the shape of the cavity to be filled on the rear of the toothbrush head. For the embodiment 10a, the insert 62 may extend further into the cavity to define the void/cavity inside the toothbrush head to be filled with dentifrice. The extent of the insert 62 into the cavity may be used to define the frangible, thin-walled cover 32a for the dentifrice described in relation to figures 7-10.

In this way, a common moulding tool can be customised to for different varieties of the toothbrush product, e.g. offering a common handle design but different features of the toothbrush head.

Once the toothbrush 10, 10a has been formed, the dentifrice material can be applied to the head portion in the desired location (i.e. within the internal cavity for embodiment 10a or in the formation between the bristles for the embodiment 10). Once the dentifrice has been applied, the toothbrush head can be closed with the dentifrice thereon, either by applying the cap 36 or by applying the plug 48. The dentifrice is now sealed on the toothbrush head in a manner that is ready for use.

The toothbrush, including the dentifrice, can then be packaged as desired.

Due to its water-soluble properties, the toothbrush is preferably sealed in a water- impervious enclosure 64, such as a wrapper, when manufactured as shown in figure 12. A variety of materials for the enclosure are available and could be considered by the skilled person. A biodegradable packaging material is preferred, albeit with a longer shelf life than the toothbrush itself. A flow wrap may provide a particularly suitable packet that can be torn open to access the toothbrush for use.

Where cross-contamination is considered a risk after use of the toothbrush, the toothbrush can be provided in a resealable enclosure, such as a packet or pouch. Thus the toothbrush can be reinserted back into the packet and sealed therein after use to reduce any risk for cross-contamination by handling. A conventional zip closure 66 or similar may be used on the enclosure. A desiccant could be provided inside the enclosure/wrapper with the toothbrush during packaging, if needed to maintain the moisture-free environment therein. An organic/biodegradable desiccant could be used, e.g. a porous salt/clay package.

Claims

Claims:

1. A toothbrush comprising a handle, a head formation and bristles on the head formation, wherein both the head formation and bristles are provided as a unitary mass of a biodegradable polymer material.

2. A toothbrush according to claim 1 , wherein the head formation and bristles comprise a continuous body of said biodegradable polymer material.

3. A toothbrush according to claim 1 or 2 where the handle comprises the head formation and is provided with the bristles as the unitary mass of biodegradable polymer material.

4. A toothbrush according to any preceding claim which breaks down in the presence of water within 7 days, 5 days or less.

5. A toothbrush according to any preceding claim, wherein the biodegradable polymer material is water soluble.

6. A toothbrush according to any preceding claim, wherein the biodegradable polymer material comprises polyvinyl alcohol.

7. A toothbrush according to any preceding claim, comprising a dentifrice material carried on the head portion.

8. A toothbrush according to claim 7, wherein the dentifrice material is surrounded by the bristles.

9. A toothbrush according to claim 7 or 8, wherein the dentifrice material comprises an organic paste provided as a mass or bead on or in the head portion.

10. A toothbrush according to any preceding claim, wherein the bristles comprise spaced elongate protrusions on the head portion, each protrusion being between 0.2 and 1 mm in width.

11. A toothbrush according to any preceding claim, wherein the bristles have a rounded, tapered or otherwise profiled distal ends.

12. A toothbrush according to any preceding claim, wherein the head formation comprises a dentifrice-receiving formation.

13. A toothbrush according to claim 12, wherein the dentifrice-receiving formation is provided amongst, within or in-between the bristles.

14. A toothbrush according to claim 12 or 13, wherein the dentifrice-receiving formation comprises a raised wall defining a recess.

15. A toothbrush according to claim 12, 13 or 14, wherein the dentifrice receiving formation comprises a domed formation defining an internal recess in the head formation.

16. A toothbrush according to any one of claims 12 to 15, wherein the dentifrice-receiving formation is frangible to release the dentifrice in use.

17. A toothbrush according to any preceding claim, comprising a closure for the head portion.

18. A toothbrush according to claim 17, wherein the closure is on the opposing side of the toothbrush from the bristles and closes an internal recess in the head formation.

19. A toothbrush according to claim 17, wherein the closure comprises removable cap for covering the bristles.

20. A toothbrush according to any preceding claim, comprising a frangible/removable portion within the handle.

21. A toothbrush according to claim 20, wherein the frangible/removable portion comprises a toothpick.

22. A toothbrush according to claim 20 or 21 , wherein the frangible/removable portion is provided as a part of said unitary mass of a biodegradable polymer material.

23. An oral hygiene article comprising the toothbrush of any preceding claim sealed inside a water impervious wrapper.

24. A method of manufacture of a toothbrush comprising moulding a head formation and bristles from the same biodegradable polymer material to form a unitary mass of said biodegradable polymer material in which the surface of the head formation and bristles is continuous.

25. A method according to claim 24 comprising providing a mould cavity having a plurality of recesses in which the bristles are formed and individually venting each of said recesses during moulding.

26. A method according to claim 24 or 25 comprising applying a dentifrice material to the toothbrush head once formed and applying a closure or wrapper around the toothbrush with the dentifrice material thereon.