Handle for a personal care implement and personal care implement

Abstract

A handle for a personal care implement includes a connector for repeatedly attaching and detaching a head to and from the handle, the handle further including a core structure, the core structure and the connector being integrally made to form a core-connector unit, wherein the core-connector unit is made of a fiber-reinforced material.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a handle for a personal care implement, in particular to a handle for an oral care implement, the handle comprising a connector for repeatedly attaching and detaching a head to the handle. The present disclosure further relates to a personal care implement comprising such a handle and a head. BACKGROUND

[0002] It is well known in the art to provide a head and a handle for an oral care implement, such as a manual toothbrush. Generally, bristle tufts for cleaning the teeth are attached to a bristle carrier or mounting surface of a brush head intended for insertion into the oral cavity of a user. A handle is usually attached to the head, which handle is held by the user during brushing. Typically, the head of a manual toothbrush is permanently connected to the handle, for example by injection moulding the bristle carrier, the handle and a neck connecting the head and the handle in one injection moulding step. After the normal life time of the toothbrush, i.e. after about three months of use, the toothbrush is discarded. In order to provide an environmentally friendly / sustainable manual toothbrush that results in less waste when the toothbrush is worn out and discarded, it is known to provide a manual toothbrush comprising a replaceable, i.e. repeatedly attachable to and detachable from the handle, head or head replacement. The consumer can re-use the handle and only purchase new / replacement heads, instead of purchasing a completely new toothbrush. Such replacements are usually cheaper than a conventional manual toothbrush and result in less waste.

[0003] For example, it is known to provide a manual toothbrush comprising a handle to which a replaceable head is attachable. The handle is provided with a cavity into which the head is insertable. In order to provide a sufficiently strong connection between the head and the handle, the brush head is shaped with a neck having coupling anchors for engaging in complementary engagement means within a collar of the handle.

[0004] In order to effectively clean the teeth, proper maneuverability of the entire toothbrush and good handling properties, which depend inter alia on the center of gravity of the handle / toothbrush, the bending stiffness and the weight of the handle and the brush head, have to be provided. Typically, the handle of a toothbrush has the shape of a linear rod to be handled and maneuvered by the user as desired. Since manual toothbrushes with replaceable brush heads comprise an inner cavity within the handle portion to receive the replaceable head, it has been found that such handles are relatively light and thus neither comfortable nor easy to turn around in the oral cavity care cavity. Furthermore, toothbrushes comprising a relatively light handle, e.g. a handle comprising less material or a handle made of a common plastic material such as polypropylene, are less comfortable to hold in the hand and can exhibit a relatively low bending stiffness. A low weight handle tends to be more flexible and a relatively low bending stiffness can result in a reduced efficiency of plaque removal on the tooth surface. In order to compensate for this drawback, the size of the cross-sectional area of the handle can be increased. However, a relatively thick handle can also reduce the convenience of rotating the toothbrush in the hand, thereby hindering the user to reach all areas in the oral cavity. In addition, it is known that users / consumers use different brushing techniques and thus it is essential to identify the optimal ergonomics of a toothbrush in order to provide a good sensory feeling during brushing when using all types of brushing techniques.

[0005] Personal care tools and oral care tools, in particular toothbrushes comprising a replaceable head, require a high quality and robust connector structure since the head is frequently attached to and detached from the handle. Defects caused by wear, fatigue or premature aging are a well-known problem and can result in a low quality perception and early replacement of the product.

[0006] Furthermore, personal care tools, in particular toothbrushes comprising a relatively light handle, e.g. a handle made of a common plastic material such as polypropylene, provide a low product quality perception during use of the tool.

[0007] It is an object of the present disclosure to provide a handle for a personal care tool which overcomes at least one of the above-mentioned drawbacks, in particular to provide a more comfortable and improved quality perception. It is a further object of the present disclosure to provide a personal care tool comprising such a handle and a head. SUMMARY

[0008] According to one aspect, a handle for a personal care tool is provided, the handle comprising a connector for repeatedly attaching and detaching a head to and from the handle, the handle further comprising a core structure which is integrally made with the connector to form a core-connector unit, wherein the core-connector unit is made of a fiber reinforced material.

[0009] According to one aspect, a personal care tool is provided, the personal care tool comprising a head and such a handle. BRIEF DESCRIPTION OF DRAWINGS

[0010] The present application is described in more detail below with reference to various embodiments and to the accompanying drawings, in which:

[0011] Figure 1 An exemplary embodiment of a personal care implement according to the present disclosure is shown, the implement comprising a head and a handle, the handle (shown in cross-section along A-A) comprising a core-connector unit, a second component, a third component and a spring-loaded snap element;

[0012] Figure 2 A perspective view of the core-connector unit of the handle of Figure 1 is shown;

[0013] Figure 3 A cross-sectional view of the handle of Figure 1 along B-B is shown;

[0014] Figure 4 A perspective view of the handle of Figure 1 is shown, without the third component and the spring-loaded snap element;

[0015] Figure 5 A perspective view of the handle of Figure 1 is shown, without the spring-loaded snap element;

[0016] Figure 6 A perspective view of the handle of Figure 1 is shown, with the spring-loaded snap element in exploded view;

[0017] Figure 7 A connector of the core-connector unit of Figure 2 is shown; and

[0018] Figure 8 Method steps for manufacturing the handle of Figure 1 are shown. DETAILED DESCRIPTION

[0019] A handle for a personal care implement according to the present disclosure comprises a connector for repeatedly attaching and detaching a head to the handle. The connector can comprise a snap-fit locking mechanism (e.g. a spring-loaded ball element) for securely attaching the head to the handle and for providing a sufficiently strong connection and stability between the head and the handle to enable a user to perform e.g. a brushing action.

[0020] The personal care implement according to the present disclosure can be any type of personal care implement, such as a wet shaving razor, or an oral care implement, preferably a manual toothbrush. The head can be any type of replaceable refill, such as a razor cartridge or an oral care refill, including but not limited to a brush head refill, an interdental or dental pick refill, a tongue / tissue cleaner refill, and a chemical applicator refill. The brush head can include at least one tooth cleaning element, such as a bristle tuft and / or an elastomeric element, fixed to a mounting surface of the head.

[0021] According to the present disclosure, the connector is integrally formed with the core structure and forms a core-connector unit together with the core structure. The core structure can be at least partially embedded in another handle material. The unit is formed as one piece that cannot be separated without destroying the unit.

[0022] The core-connector unit is made of a fiber-reinforced material. The fiber-reinforced material can be a composite made of a polymer matrix reinforced with fibers. The polymer matrix material can be selected from the group comprising polyamide (PA, such as PA6, PA66), styrene acrylonitrile resin (SAN), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), recycled plastic material, or mixtures thereof. The polymer matrix material can at least partially contain recycled plastic material.

[0023] Styrene acrylonitrile (SAN) as a polymer matrix material can provide high heat resistance properties. The acrylonitrile units in the chain give SAN a glass transition temperature of more than 100 °C. During the molding step, the properties of SAN can allow for a reduced cycle time due to the relatively early and fast transition temperature. By injection molding the fiber-reinforced material of the present disclosure, the temperature of the material melt is above the Tg region (viscous or rubber state). During cooling, the composite reaches the high Tg temperature early and reaches dimensional stability (glass state). Due to the high Tg of the material, the material remains dimensionally stable, so that overmolding of the fiber-reinforced material is possible.

[0024] Polybutylene terephthalate (PBT) and / or polyethylene terephthalate (PET) as a polymer matrix material can provide high quality surface properties to the handle, including improved optical properties and high impact strength. Once heated, polybutylene terephthalate and polyethylene terephthalate represent a high-temperature resistant melt with low viscosity and high melt flow index (MFI). Thus, the processability of the fiber-reinforced material during molding is improved.

[0025] Polyamides (PA) are defined as polymers having repeating units linked by amide bonds. Polyamides exhibit high durability and strength. For example, polycaprolactam (PA6) and nylon 6-6 (PA66) have high tensile strength, rigidity, good head under stability, and elasticity and gloss. PA6 and PA66 are highly resistant to abrasion and chemicals such as acids and bases. PA6 is typically white and can be dyed into various colors before production.

[0026] The fibers can be selected from the group comprising inorganic microparticles, glass fibers, carbon fibers, aramid fibers, basalt fibers, wood fibers, or any combination thereof. Glass fibers can improve the strength, elasticity, and heat resistance of the polymer matrix material. Carbon fibers and aramid fibers can improve the elasticity, tensile and compressive strength of the polymer matrix material. Wood fibers can improve the flexural strength, tensile modulus, and tensile strength of the polymer matrix material. Inorganic microparticles can improve the isotropic shrinkage, abrasion, and compressive strength of the polymer matrix material.

[0027] The fiber-reinforced material can comprise about 10 wt% to about 50 wt%, or about 25 wt% to about 35 wt% or about 30 wt% of fibers. The core-connector unit can be made of a glass fiber-reinforced polymer material comprising about 30 wt% of glass fibers. The polymer material can be a polyamide or a polybutylene terephthalate, a polyethylene terephthalate, or a combination of polybutylene terephthalate and polyethylene terephthalate.

[0028] The glass fibers embedded in the polymer material can provide a significantly increased stiffness, abrasion resistance, and integrity to the polymer material forming the core-connector unit. For personal tools, such as oral care handles whose heads are frequently detached and reattached, such material provides abrasion resistance to the connector, allowing the handle to be used for a longer period of time. Lasting connector properties are particularly important for toothbrushes, as the head and handle are often soiled with slurry and toothpaste containing abrasive particles. If the connector material is not sufficient to resist the abrasives, the abrasives can wear off / abrade the material of the connector, thereby changing the external geometry of the connector. As a result, the connector can lose its functionality and / or its ability to hold the head firmly in place during use, e.g., during brushing.

[0029] The fiber-reinforced material can have a density of about 1 g / cm 3 to about 1.7 g / cm 3 , preferably about 1.4 g / cm 3 .

[0030] The shank can further include a second component at least partially covering the core structure. The core-connector unit can define, with the second component, an overall length extension of the shank. The length extension of the shank can extend from a proximal end closest to the head to a distal end opposite the proximal end. The second material can include a filler material, such as an inorganic filler material. The inorganic filler material can be selected from the group including zinc oxide, iron oxide, barium sulfate, titanium dioxide, aluminum oxide, or any combination thereof. The filler material can comprise about 50 wt% to about 80 wt% of the polymeric material. Zinc oxide, iron oxide, barium sulfate, and titanium dioxide have a density of at least 4 g / cm 3 and thus can provide a relatively heavy weight to the polymeric material forming the second component. Further, if zinc oxide and / or aluminum oxide are used as the filler material, a relatively high thermal conductivity of the second component can be provided.

[0031] The second component can be made of a polymeric material including a matrix material and an inorganic filler material, where the matrix material can be selected from the group consisting of polyamide, styrene acrylonitrile resin, polybutylene terephthalate, polyethylene terephthalate, recycled plastic material, or a mixture thereof. The polymeric matrix material can at least partially contain recycled plastic material. The inorganic filler material can comprise about 50 wt% to about 80 wt% of the polymeric material.

[0032] Styrene acrylonitrile (SAN) as a polymeric matrix material can provide high heat resistance properties. The acrylonitrile units in the chain give SAN a glass transition temperature greater than 100 °C. During the molding step, the properties of SAN can allow for reduced cycle times due to the relatively early and fast transition temperature. Amorphous polymers are suitable for the heavy weight resin material of the present disclosure due to the glass transition temperature Tg at which the amorphous polymer reversibly transforms from a viscous or rubbery state to a hard state. By injection molding the fiber reinforced material of the present disclosure, the temperature of the material melt is above the Tg region (viscous or rubbery state). During cooling, the composite reaches the high Tg temperature early and reaches dimensional stability (glass state). Due to the high Tg of the material, the material remains dimensionally stable, thus overmolding of the fiber reinforced material is possible.

[0033] Polybutylene terephthalate (PBT) and / or polyethylene terephthalate (PET) as a polymeric matrix material can provide the shank with high quality surface properties, including improved optical properties and high impact strength. Once heated, polybutylene terephthalate and polyethylene terephthalate represent a high temperature resistant melt with low viscosity and high melt flow index (MFI). Thus, the processability of the fiber reinforced material during molding is improved.

[0034] Polyamides (PA) are defined as polymers having repeating units linked by amide bonds. Polyamides exhibit high durability and strength. For example, polycaprolactam (PA6) and nylon 6-6 (PA66) have high tensile strength, rigidity, good head under water stability, as well as elasticity and gloss. PA6 and PA66 are highly resistant to abrasion and chemicals such as acids and bases. PA6 is typically white and can be dyed into various colors before production.

[0035] The polymeric material of the second component has a density of about 2 g / cm3 3 to about 3.5 g / cm3 3 , preferably about 2.7 g / cm3 3 . A density of about 2.7 g / cm3 3 may be provided by a polymeric material comprising an inorganic filler material and a matrix material, wherein the matrix material can be a polyamide and wherein the inorganic filler material can be zinc oxide in an amount of about 70 wt% to about 75 wt% of the polymeric material.

[0036] In case zinc oxide is used as filler material having a substantially white / light color, the second component matrix material can be colored using any type of dye. A dye masterbatch can simply be added to the matrix material / second component material instead of applying an additional coating, for example by galvanizing the second component and / or using a colored coating (which would be required if a black / dark filler material, for example iron oxide, is used).

[0037] At a density of about 2 g / cm3 3 to about 3.5 g / cm3 3 , preferably about 2.7 g / cm3 3 , the second component is significantly heavier compared to commonly used handle materials (for example, polypropylene having a density of only about 0.9 g / cm3 3 and provides a different haptic impression to the consumer during use of the handle. Since the weight of the handle material can be relatively high, this can provide a high quality perception and a comfortable feeling for the user during use of the personal care implement. Typically, especially in the field of personal care, users are accustomed to products having a certain specific weight which ensures a high product quality and provides a comfortable feeling during use of the product. Thus, the handle for a personal care implement according to the present disclosure can provide such an excellent product quality perception.

[0038] By using different materials for the core-connector unit and the second component, respectively, the handle properties can be improved in different aspects at the same time. The second component, which comprises a relatively large amount of filler material (i.e. at least 50 wt.-%), provides a high specific weight to the entire handle as well as a higher thermal conductivity and heat capacity compared to a handle made of, for example, polypropylene. Thus, the handle according to the present disclosure can be considered a high-quality handle compared to a handle made of a standard plastic material. High weight / low temperature are properties typically associated with materials like metals or ceramics, which typically indicate a higher level of quality and price point.

[0039] On the other hand, however, a material with a large amount of filler material is more brittle than a standard plastic material and thus can be more prone to breakage, for example, if the handle is dropped to the ground or hits a hard object. Surprisingly, it has been found that a core structure according to the present disclosure can compensate for the brittle properties of the second component if the core structure comprises a length extension that extends at least 20%, preferably at least 25%, further preferably at least 50%, even more preferably at least 75% or at least 85% of the total length of the handle. By adding fibers (e.g. glass fibers) to the polymer matrix material, the properties of the polymer matrix are improved in terms of strength, elasticity and heat resistance. According to the present disclosure, the fiber-reinforced material forming the core structure can compensate for the increased brittleness of the polymer material of the second component and can ensure the integrity of the product throughout its lifetime (e.g. when the handle is dropped to the floor). By forming the connector together with the core structure, a secure attachment of the head to the handle can also be ensured. Since not only the core structure, but also the connector is formed from a fiber-reinforced material, the fit of the head on the connector of the handle is less likely to wear during the entire lifetime of the personal care implement, thus not only providing a high-quality consumer product, but also a more sustainable and ecologically friendly personal care implement.

[0040] Furthermore, since the connector and the core structure are made in one piece, for example, in a single injection molding step, the manufacturing can be simplified and the manufacturing costs are reduced. In addition, the combination of specific materials for the core-connector unit and the second component allows for a simple overmolding of the polymer material of the core-connector unit with the second component without the need for complex assembly steps.

[0041] The core structure can comprise at least one or more protrusions, for example, extending from the length extension of the core structure in substantially orthogonal directions. Such protrusions can facilitate and enable a secure connection and mechanical interlock between the core structure and the second component. The protrusions can be in the form of ribs, fins, strips, bridges and / or nubs.

[0042] A circular grommet / ring can be formed integrally with the core-connector unit, for example, in one injection molding step. The grommet / ring can be provided at the intersection between the connector and the core structure. Such a grommet / ring can ensure a tight connection between the core-connector unit and the second component. When the second component material is molded onto the core structure, the material of the second component shrinks to some extent and thus provides a pressure fit between the core-connector unit and the second component, which ensures a firm and tight connection between the core-connector unit and the second component. Since the grommet is provided at the intersection between the connector and the core structure, the grommet can form a support / contact area for the second component.

[0043] The grommet / ring can include a step or groove provided in the area in direct contact with the second component. When the step provided in the outer geometry of the grommet is overmolded by the material of the second component, a very tight fit between the core-connector unit and the second component can be provided. Such a tight fit can eliminate any deep gaps between the core-connector unit and the second component in which toothpaste paste can otherwise accumulate, making the handle more hygienic. The step can have a relatively small dimension, for example, a height of about 0.5 mm to about 1.5 mm, still providing the benefit of a tight fit. If the height of the step is relatively small, for example, about 0.5 mm to about 1.5 mm, the layer of the second component material covering the step can be correspondingly relatively thin, i.e., about 0.5 mm to about 1.5 mm.

[0044] The pressure fit according to the present disclosure can also be referred to as an interference fit or shrink fit, and is a form of fastening between two closely fitted mating parts that results in a joint that is held together by friction after the parts are pushed together. The pressure fit or shrink fit allows the components to be joined without the application of an external force; the pressure fit / shrink fit is automatically provided by the relative size change after molding when the second component returns to normal room temperature. By heating the material of the second component to allow molding onto the core-connector unit and by returning the material to ambient / room temperature, a tight shrink fit between the core-connector unit and the second component can be provided. Such a tight mechanical connection, i.e., the tight pressure fit / shrink fit according to the present disclosure, can also enable the use of handle materials (for the core-connector unit and the second component, respectively) that do not form chemical bonds after molding.

[0045] The grommet can abut and thus can be in direct contact with the second component at least partially covering the core structure to provide an even tighter connection. Furthermore, the grommet can be substantially flush with the second component and can provide a uniform outer lateral surface of the handle body without any gaps or edges in which paste and slurry can accumulate. Thus, such a handle provides an excellent haptics and makes the personal care implement more hygienic.

[0046] To provide improved gripping properties of the handle, a third component, e.g. a thermoplastic elastomer material (TPE) and / or a polypropylene material, can be overmoulded onto the core structure and / or the second component. The third component can provide a gripping area on the outer surface of the handle.

[0047] For example, the handle can comprise a thumb rest made of a third component, e.g. a thermoplastic elastomer material and / or a polypropylene material. As discussed above, these materials can be easily injection moulded over the core structure and / or the second component. Such a thumb rest can provide the handle of the personal care implement with improved handling properties, e.g. anti-slip properties, to improve the maneuverability of the personal care implement under wet conditions, e.g. when the user brushes his teeth. The thumb rest can be made of a thermoplastic elastomer having a Shore A hardness of about 30 to about 60, or about 40, in order to prevent the oral care implement from being too slippery when used under wet conditions. At least a portion of the thumb rest can have a concave shape having an angle a of about 20° to about 25° or about 24° with respect to the area of the rest of the thumb rest. Alternatively, the thumb rest can be an elongated strip extending along the length extension of the handle. The thumb rest or gripping area can be attached to the front surface of the handle in an area close to the proximal end, i.e. closest to the head. The thumb rest can comprise a plurality of ribs extending substantially perpendicular and / or diagonally to the longitudinal axis of the handle. Such ribs can allow the user / consumer to use the personal care implement with even more control. The user / consumer can better hold and maneuver the handle during use. Such a handle can provide further improved control and greater comfort during use, e.g. brushing, especially under wet conditions.

[0048] The third component can not only form a thumb rest on the front surface of the handle, but also a palm grip to be gripped by the fingers and thumb of the user / consumer on the rear surface opposite the front surface. This handle configuration can even further resist slipping during use. The third component material, e.g. TPE, can extend through apertures provided in the underlying second component and / or core structure.

[0049] A method of manufacturing a handle for a personal care implement can comprise the following steps:

[0050] - moulding a core-connector unit from a fibre-reinforced material, the core-connector unit comprising a core structure and a connector for attaching a head to the handle, the connector comprising a cavity,

[0051] - at least partially overmoulding the core-connector unit using a polymeric material to form a second component, the polymeric material comprising a filler material,

[0052] - using a material at least partially overmolding the core-connector unit and / or the second component to form a third component (preferably a thermoplastic elastomer) to form a grip portion of the handle,

[0053] - inserting a snap-fit element into the cavity of the connector.

[0054] The snap-fit element can be a spring-loaded ball element. To this end, a spring, a ball and a cap-like piece holding the compressed spring and ball in place can be inserted into the cavity of the connector. The cap-like piece can be fixed in the cavity by, for example, a press fit and / or ultrasonic welding. The cap-like piece can be made of a fiber-reinforced material according to the present disclosure or of a different material, such as a metal.

[0055] A portion of the core structure can remain visible on the outside of the handle, for example to provide an additional color contrast structure, thereby improving the aesthetic appearance of the handle. For example, an area presenting a logo can be provided by a portion of the core structure that does not comprise overmolding and thus remains visible.

[0056] The handle according to the present disclosure can comprise about 5 wt.% to about 20 wt.% of the fiber-reinforced material forming the core-connector unit, about 70 wt.% to about 95 wt.% of the polymeric material comprising a filler and forming the second component, and about 1 wt.% to about 10 wt.% of the third component material (preferably a thermoplastic elastomer) to form a grip portion of the handle.

[0057] The handle according to the present disclosure can comprise about 13 wt.% to about 18 wt.% of the fiber-reinforced material forming the core-connector unit, about 75 wt.% to about 85 wt.% of the polymeric material comprising a filler and forming the second component, and about 2 wt.% to about 5 wt.% of the third component material (preferably a thermoplastic elastomer) to form a grip portion of the handle.

[0058] Since the material of the handle (material of the core-connector structure and the second component) can have a higher density than the material of the head (made of polypropylene), the center of mass / center of gravity is located within the handle (even if the brush head is loaded with toothpaste), which enables the user to perform a well-coordinated brushing technique with improved sensory feeling during brushing. The center of gravity arranged in the center of the handle provides an oral care implement that, once toothpaste is applied to the brush head, is better balanced and does not tip over / does not cause the head to be biased. Furthermore, the oral care implement according to the present disclosure has the advantage that the center of gravity is located at or very close to the pivot point of the wrist joint when the user applies different grip styles / brushing techniques. A balanced toothbrush is easier to control in the oral cavity, thereby allowing more precise and accurate brushing movements, which enable a better cleaning.

[0059] While the high quality and relatively expensive handle of the personal care implement is suitable for use over a longer period of time compared to commonly used implements, e.g. a manual toothbrush which is discarded after use of about three months, the relatively inexpensive replacement can be exchanged regularly, e.g. after about three months. This provides a cost effective and environmentally sustainable high quality personal / oral care implement.

[0060] Furthermore, as the polymer material of the second component can comprise a relatively large amount of filler material, which can be pre-mixed with at least a portion of the matrix material, such polymer material can allow for controlling the weight of the handle in any position, e.g. by filler variation. As the relatively high weight of the handle, control of the overall personal care implement can be beneficial. It is now possible to adapt the moment of inertia of the finished handle using the mass / weight distribution of the polymer material.

[0061] As discussed above, the head of the personal care implement can be attached to the handle via a connector comprising a snap-fit element / snap-fit locking mechanism to ensure a sufficiently strong connection and stability between the head and the handle, e.g. to enable the user to perform a brushing action. The connector can have an outer side surface and a recess therein forming a cavity within the connector. Within the cavity, a spring-loaded ball element can be provided. The spring-loaded ball element comprises a ball and a spring exerting a radial force on the ball in a direction towards the outer side surface of the connector. In the following, the radial force is defined by a force exerted in a direction substantially perpendicular to the longitudinal length extension of the connector. The spring exerts a force on the ball and pushes the ball outwards such that the ball extends slightly beyond the outer side surface of the connector. The inner wall of the hollow portion provided in the head can comprise a recess for receiving the ball of the spring-loaded ball element. Once the head is snap-fitted onto the connector, the head is fixed in an axial direction on the handle / connector. In other words, the connector allows for easy attachment / detachment of the head to / from the handle. The user can attach the head to the handle by a simple linear motion. Furthermore, the ball snap can provide a precise fixation of the head and can provide the user with a clear tactile feedback that the head is securely snap-fitted. In other words, once the ball engages into the recess provided in the inner wall of the hollow portion of the head, the user can recognize this. The brush head can be easily removed, i.e. no synchronized action with other elements / unlocking mechanism needs to be performed.

[0062] The head can be fixed on the handle until a specific / predetermined pull-off force is applied. The connection between the head and the connector is strong enough to enable a well-coordinated brushing technique. The head does not come loose from the handle and does not twist aside during use, e.g. brushing.

[0063] The ball of the spring-loaded ball element and / or the spring can be made of stainless steel. While typical snap elements include spring elements made of plastic that show relaxation and aging effects over time, stainless steel springs show a constant spring stiffness over time, also under prolonged use conditions (e.g. temperature). Spring-loaded ball elements made of stainless steel can provide a durable, reliable fixation of the head on the connector / handle.

[0064] The connector can include a first substantially cylindrical section and a second substantially cylindrical section, wherein the first cylindrical section and the second cylindrical section can be connected by an at least partially conically shaped section. The first substantially cylindrical section, the at least partially conically shaped section and the second substantially cylindrical section can be arranged in a continuous sequence and can define a longitudinal length extension of the connector. The first substantially cylindrical section and the second substantially cylindrical section can be placed off-center with respect to the longitudinal length extension of the connector.

[0065] In the following, a substantially cylindrical section is defined by a three-dimensional body having a longitudinal length extension and a cross-sectional area extending substantially perpendicular to the longitudinal length extension. The cross-sectional area has a shape that is substantially constant along the longitudinal length extension. Since the connector can be manufactured by an injection molding process, the substantially cylindrical section also includes a section / body having a slight draft angle of at most 2°. In other words, the substantially cylindrical section also includes a section / body that slightly tapers at most 2° towards the proximal end closest to the head once the head is attached to the connector.

[0066] The cross-sectional area can have any shape, such as substantially circular, elliptical, rectangular, semicircular, circular with flat portions, convex or concave. The cross-sectional area can have a polygonal shape, such as a square or triangular shape. A circumferential surface of the cylinder along the length extension of the cylinder can be defined as consisting of straight lines that are substantially parallel with respect to the longitudinal length extension of the cylinder.

[0067] The head of the oral care implement has a distal end and a proximal end, the proximal end being defined as the end closest to the handle. The proximal end of the head can comprise a hollow portion for receiving a portion of the connector, e.g. a second substantially cylindrical section, an at least partially conically shaped section and a portion of the first substantially cylindrical section. The hollow portion of the head can have an inner wall, the geometry / profile of which corresponds to the outer geometry / profile of the portion of the connector to be inserted into the hollow portion of the head. The eccentric arrangement / offset central positioning of the substantially cylindrical sections of the connector enables precise positioning of the brush head on the handle. The geometric position of the head can be unambiguously defined. As the handle comprises the connector at the proximal end closest to the head, the eccentric / offset central arrangement of the two substantially cylindrical sections can act as a guiding element when the user attaches the head to the handle. In other words, the two substantially cylindrical sections can allow for a precise fit between the head and the handle. Furthermore, the eccentric / offset central arrangement of the two substantially cylindrical sections can provide anti-twist protection for the head on the handle during brushing, e.g. if lateral forces are applied onto the head.

[0068] The first substantially cylindrical section and the second substantially cylindrical section have a length extension and a cross-sectional area extending substantially perpendicular to the length extension, and the cross-sectional area of the first substantially cylindrical section and / or the second substantially cylindrical section can be substantially circular. This geometry provides a robust and simple structure which is easy to clean after use of the oral care implement. Furthermore, as the outer geometry is relatively simple, such a connector can be manufactured in a cost-effective manner.

[0069] The first substantially cylindrical section can have a cross-sectional area which is larger than the cross-sectional area of the second substantially cylindrical section. For example, the first substantially cylindrical section to be inserted into the hollow portion at the proximal end of the handle can have a substantially circular cross-sectional area with a diameter of about 8 mm to about 10 mm, preferably about 9 mm, while the second substantially cylindrical section to be inserted into the hollow portion at the proximal end of the head can have a substantially circular cross-sectional area with a diameter of about 4 mm to about 6 mm, preferably about 5 mm.

[0070] The first and second substantially cylindrical sections can each have a first and second longitudinal central axis defined as the axis of symmetry of the first and second substantially cylindrical sections, respectively. The first and second substantially cylindrical sections can be placed / arranged relative to each other such that the second longitudinal central axis of the second cylindrical section is positioned off-center relative to the first longitudinal central axis of the first cylindrical section by about 1 mm to about 2.5 mm, or about 1.5 mm to about 2 mm, or about 1.65 mm. In other words, the center of the second substantially cylindrical section is offset / eccentric from the longitudinal central axis of the first substantially cylindrical section by a distance of about 1 mm to about 2.5 mm, or about 1.5 mm to about 2 mm, or about 1.65 mm.

[0071] Such a connector can be easily manufactured, e.g., by injection molding, and provides sufficient torsional stability to an oral care implement if lateral forces are applied on the head.

[0072] The first and / or second substantially cylindrical sections can comprise a flat portion extending along the length extension of the first and / or second substantially cylindrical sections. Such a flat portion can provide additional torsional protection of the head of the personal care implement, e.g., a toothbrush, connected to the handle during use, e.g., tooth brushing, e.g., if lateral forces are applied on the head.

[0073] The first and second substantially cylindrical sections can each have a first and second outer surface, and the first and second substantially cylindrical sections can be arranged relative to each other such that a portion of the first outer surface and a portion of the second outer surface are substantially in line. A flat portion, optionally comprising a spring-loaded ball element, can be arranged opposite the substantially in line first and second outer surfaces. Such a connector has an easy-to-clean exterior geometry. The connector is robust, easy to use, and can be manufactured in a cost-effective manner.

[0074] The proximal end of the handle, e.g., a ring / collar disposed at the intersection between the connector and the core structure, can comprise a beveled surface. Such a beveled surface can provide additional torsional protection of the oral care implement during use. The beveled surface and the cross-sectional area of the handle can define an angle a of about 15° to about 30°, or about 18° to about 28°, or about 25°. The cross-sectional area is defined by an area extending substantially perpendicular to the longitudinal length extension of the handle. Surprisingly, it has been found that such an angled / beveled surface provides superior torsional protection. Furthermore, the angled / beveled surface allows for draining of fluids such as toothpaste slurry and saliva after use of the oral care implement, thereby preventing such fluids from accumulating over time.

[0075] The connector allows the head to be easily attached to / detached from the handle. The user can attach the head to the handle by a simple linear motion. With the specific design of the substantially cylindrical section arranged off-center and the beveled surface of the handle, the head is automatically turned to the correct orientation (within a certain tolerance) during the attachment motion. Thus, the consumer is not forced to precisely position the head on the handle before snapping the head onto the handle. Furthermore, the ball snap provides a precise fixation of the brush head and provides the consumer with a clear tactile feedback that the head is securely snapped. The brush head can be easily removed without requiring any simultaneous action with other elements (an unlock mechanism). Furthermore, the connector can be easily cleaned. This specific design of the connector can not have any recesses in which dirt, toothpaste, and / or saliva can accumulate. The connector can also avoid any fragile structures by only comprising a substantially rounded edge, which can prevent an easy breakage or damage of the surface.

[0076] To allow the brush head to fit well enough on the connector in case of manufacturing tolerances, the inner wall of the hollow portion of the head can comprise at least one split or two splits arranged opposite to each other to precisely adjust the head on the connector / handle. Furthermore, the at least one split can prevent air compression in the hollow portion of the head, which can act like a spring or as an additional resistance when snapping the head on the connector / handle.

[0077] The personal care implement can be an oral care implement, in particular a toothbrush comprising a handle and a toothbrush head having tooth cleaning elements.

[0078] The tooth cleaning elements of an oral care implement, such as the filament bundles forming one or more tufts, can be attached to the head by a hot tufting process. A method of manufacturing a head having filament tufts embedded in the head can comprise the following steps: in a first step, a tuft is formed by providing a desired amount of filaments. In a second step, the tuft is placed in a mold cavity such that the ends of the filaments that should be attached to the head extend into the cavity. The opposite ends of the filaments that do not extend into the cavity can be end-rounded or non-end-rounded. For example, in the case of the filaments being tapered filaments having a sharp tip end, the filaments can be non-end-rounded. In a third step, a head is formed around the ends of the filaments extending into the mold cavity by an injection molding process, thereby anchoring the tuft in the head. Alternatively, the tuft can be anchored by forming a first portion of the head (a so-called "sealing plate") around the ends of the filaments extending into the mold cavity with an injection molding process before the rest of the oral care implement is formed. Prior to starting the injection molding process, the ends of the tuft extending into the mold cavity can optionally be melt or fusion bonded to join the filaments together in a fusion body or melt ball such that the fusion body or melt ball is located within the cavity. The tuft can be held in the mold cavity by a molding stick having a blind hole that corresponds to the desired location of the tuft on the finished head of the oral care implement. In other words, the tufts attached to the head by the hot tufting process are not stacked on an intermediate portion along their length and are not installed in the head using anchors / pegs. The tufts can be installed on the head with a tufting process that does not involve anchors.

[0079] Alternatively, a head for an oral care implement can be provided with a bristle carrier having at least one tuft hole (e.g., a blind end hole). A tuft comprising a plurality of filaments can be fixed / anchored in the tuft hole by a stapling process / anchored tufting method. This means that the filaments of the tuft are bent / folded around an anchor, e.g., made of metal, in a substantially U-shaped manner, e.g., an anchor line or an anchor plate. The filaments are pushed into the tuft hole together with the anchor such that the anchor penetrates into the opposing side walls of the tuft hole, thereby anchoring / fixing / fastening the filaments to the bristle carrier. The anchor can be fixed in the opposing side walls by positive frictional engagement. In the case of the tuft hole being a blind end hole, the anchor holds the filaments against the bottom of the hole. In other words, the anchor can be located in a substantially perpendicular manner over the U-shaped bend. As the filaments of the tuft are bent around the anchor in a substantially U-shaped configuration, a first branch and a second branch of each filament extend from the bristle carrier in the filament direction. The type of filaments that can be used / suitable for use in the stapling process are also referred to as "double-sided filaments". The head for an oral care implement manufactured by the stapling process can be provided in a relatively low cost and time efficient manner.

[0080] The following is a non-limiting discussion of exemplary embodiments of personal care implements and parts thereof according to the present disclosure, with reference to the accompanying drawings.

[0081] Figure 1 A personal care implement 10, in this particular embodiment a manual toothbrush 10, is shown. The manual toothbrush 10 comprises a handle 12 and a head 14, which is repeatedly attachable to and detachable from the handle 12 via a connector 16. The handle 12 can be formed by using a process as shown in the flow chart of Figure 8 and as further explained below.

[0082] The handle 12 comprises the connector 16, which is integrally made with a core structure 18 to form a core-connector unit 20, a second component 22, a third component 24, and a spring-loaded snap element 26.

[0083] The core-connector unit 20 (shown in detail in Figure 2 ) is made of a fiber-reinforced material. The fiber-reinforced material is a composite material comprising a polymer matrix material and fibers. The composite material can comprise about 10 wt.% to about 50 wt.%, preferably about 25 wt.% to about 35 wt.%, further preferably about 30 wt.% of fibers. The fibers can be selected from the group comprising glass fibers, carbon fibers, aramid fibers, basalt fibers, wood fibers, or any combination thereof. The polymer matrix material can be selected from the group comprising polyamide, styrene acrylonitrile resin, polybutylene terephthalate, polyethylene terephthalate, recycled plastic material, or mixtures thereof. The polymer matrix material can at least partially contain recycled plastic material. In this particular embodiment, the fiber-reinforced material can comprise polyamide as the polymer matrix material and about 30 wt.% to about 35 wt.% of glass fibers.

[0084] The fiber-reinforced material has a density of about 1 g / cm 3 to about 1.7 g / cm 3 (in this particular embodiment about 1.4 g / cm 3 ).

[0085] As shown in Figure 3 and Figure 4 , the core structure 18 of the core-connector unit 20 is partially embedded in / overmolded by the second component 22.

[0086] The core-connector unit 20 together with the second component 22 defines an overall length extension 28 of the handle 12. The length extension 28 of the handle 12 extends from a proximal end 30 closest to the head 14 to a distal end 32, which is opposite to the proximal end 30.

[0087] The second component is made of a polymeric material comprising a matrix material and a filler material, preferably an inorganic filler material, wherein the matrix material is selected from the group consisting of polyamide, styrene acrylonitrile resin, polybutylene terephthalate, polyethylene terephthalate or mixtures thereof, and wherein the filler material can constitute about 50 wt% to about 80 wt% of the polymeric material. The filler material is selected from the group comprising zinc oxide, iron oxide, barium sulfate, titanium dioxide, aluminum oxide or any combination thereof. In this particular embodiment, the second component can be made of a polymeric material comprising polyamide as the matrix material and about 60 wt% to about 75 wt% of zinc oxide.

[0088] The polymeric material of the second component has a density of about 2 g / cm 3 to about 3.5 g / cm 3 (in this particular embodiment about 2.7 g / cm 3 ).

[0089] To compensate for the fragile nature of the second component 22, the core structure 18 includes a length extension 34 that extends at least 20%, preferably at least 25%, further preferably at least 50%, even more preferably at least 75% or at least 85% of the length extension 28 of the handle 12. In this particular embodiment, the core structure 18 extends at least 85% of the length extension 28 of the handle 12. By adding glass fibers to the polymeric matrix material, the properties of the polymeric matrix in terms of strength, elasticity and heat resistance are improved.

[0090] The core structure 18 further includes a plurality of protrusions 36 extending from the length extension 34 of the core structure 18 in a substantially orthogonal direction. The protrusions 36 facilitate and enable a secure connection and mechanical interlock between the core structure 18 and the second component 22. The protrusions can have the form of ribs, fins, strips, bridges and / or nubs (see Figure 2 and Figure 3 ).

[0091] The connector 16 of the core-connector unit 20 further includes a ring / rim 38 at the intersection 40 with the core structure 18 to ensure a tight connection between the core-connector unit 20 and the second component 22 (see Figure 2 and Figure 7). The collar / annulus 38 includes a step 39 or groove 38 disposed in the area in direct contact with the second component 22. When the step / groove 39 disposed in the outer geometry of the collar 38 is overmolded with the material of the second component 22, a very tight fit can be provided between the core-connector unit 20 and the second component 22. Such a tight fit can eliminate any gap between the core-connector unit 20 and the second component 22 in which toothpaste slurry could otherwise accumulate, making the handle more hygienic. The step 39 can have a relatively small dimension, such as a height 41 of about 0.5 mm to about 1.5 mm, to still provide the benefit of a tight fit. If the height 41 of the step is relatively small, such as about 0.5 mm to about 1.5 mm, the layer 42 of the second component material covering the step / groove 39 can be correspondingly relatively thin, i.e., about 0.5 mm to about 1.5 mm. When the second component material 22 is molded onto the core structure 18, the material of the second component shrinks to some extent. Thus, a press fit is provided between the core structure 18 and the second component 22, which ensures a secure connection between the core-connector unit 20 and the second component 22.

[0092] To provide improved grip properties of the handle 12, a third component 24 (e.g., a thermoplastic elastomer material (TPE) and / or a polypropylene material) can be overmolded onto the core structure 18 and / or the second component 22. The third component 24 provides a grip region 44 (see Figure 5 and Figure 6 ) on an outer surface 46 of the handle 12. In this particular embodiment, an elongated strip 48 of TPE material is disposed on a front surface 50 of the handle 12.

[0093] Figure 8 Method steps of manufacturing the handle 12 for the personal care implement 10 are shown.

[0094] In a first step 100, the core-connector unit 20, including the core structure 18 and the connector 16 for attaching the head 14 to the handle 12, is molded, preferably injection molded, from a fiber reinforced material, the connector 16 including the cavity 52.

[0095] In a second step 200, the core-connector unit 20 is at least partially overmolded, preferably injection molded, with a polymeric material to form the second component 22, the polymeric material including a filler material.

[0096] In a third step 300, the core-connector unit 20 and / or the second component 22 is at least partially overmolded, preferably injection molded, with a material to form the third component 24 (preferably a thermoplastic elastomer) to form a grip portion or region 44 of the handle 12.

[0097] In a fourth step 400, the snap-fit element 26 is inserted into the cavity 52 of the connector 16. The snap-fit element 26 can be a spring-loaded ball element. To this end, the spring 54, the ball 56 and the cap 58 holding the compressed spring 54 and the ball 56 in place can be inserted into the cavity 52 of the connector 16. The cap 58 can be fixed in the cavity 52 by, for example, a press fit and / or ultrasonic welding. The cap 58 can be made of a fiber-reinforced material according to the present disclosure or of a different material, for example a metal.

[0098] In the context of the present disclosure, the term "substantially" refers to an arrangement of elements or features that, while theoretically expected to exhibit exact uniformity or behavior, can in fact embody some less exactness in a certain thing. Likewise, the term represents a degree to which a quantitative value, measurement, or other related representation can differ from the reference without causing a change in the basic function of the subject matter at issue.

[0099] The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the exact value and a functional equivalent ranging approximately thereabout. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm."

Claims

1. A handle (12) for a personal care tool (10), the handle (12) including a connector (16) for repeatedly attaching and detaching a head (14) from the handle (12), the handle (12) further including a core structure (18) integrally formed with the connector (16) to form a core-connector unit (20), wherein the core-connector unit (20) is made of a fiber-reinforced material, wherein a bushing disposed at the junction between the connector and the core structure includes a chamfered surface, the chamfered surface defining an angle of 15° to 30° with a cross-sectional area extending perpendicular to a longitudinal length extension of the handle.

2. The handle (12) according to claim 1, wherein the fiber reinforcement material comprises 10% to 50% by weight of fibers.

3. The handle (12) according to claim 2, wherein the fiber reinforcement material comprises 25% to 35% by weight of fibers.

4. The handle (12) according to claim 3, wherein the fiber reinforcement material comprises 30% by weight of fiber.

5. The handle (12) according to any one of claims 1 to 4, wherein the fiber is selected from the group consisting of glass fiber, carbon fiber, aramid fiber, basalt fiber, wood fiber or any combination thereof.

6. The handle (12) according to any one of claims 1 to 4, wherein the fiber reinforcement material is a composite material comprising a polymer matrix material.

7. The handle (12) according to claim 6, wherein the polymer matrix material is selected from the group consisting of polyamide, styrene-acrylonitrile resin, polybutylene terephthalate, polyethylene terephthalate, recycled plastic material or mixtures thereof.

8. The handle (12) according to any one of claims 1 to 4, wherein the handle (12) has an overall length extension (28) extending from a proximal end (30) closest to the head (14) to a distal end (32) opposite to the proximal end (30), and the core structure (18) extends at least 20% along the overall length extension (28) of the handle (12).

9. The handle (12) according to claim 8, wherein the core structure (18) extends at least 25% along the overall length extension (28) of the handle (12).

10. The handle (12) according to claim 9, wherein the core structure (18) extends at least 50% along the overall length extension (28) of the handle (12).

11. The handle (12) according to claim 10, wherein the core structure (18) extends at least 75% along the overall length extension (28) of the handle (12).

12. The handle (12) according to claim 11, wherein the core structure (18) extends at least 85% along the overall length extension (28) of the handle (12).

13. The handle (12) according to any one of claims 1 to 4, wherein the handle (12) further comprises a second component (22) that at least partially covers the core structure (18).

14. The handle (12) according to claim 13, wherein the second component (22) comprises a polymer material, the polymer material comprising a filler material.

15. The handle (12) according to claim 14, wherein the filling material is an inorganic filling material.

16. The handle (12) according to claim 14, wherein the filler material is selected from the group consisting of zinc oxide, iron oxide, barium sulfate, titanium dioxide, aluminum oxide or any combination thereof.

17. The handle (12) according to claim 13, wherein the second component (22) is made of a polymeric material comprising a matrix material and an inorganic filler material, wherein the matrix material is selected from the group consisting of polyamide, styrene-acrylonitrile resin, polybutylene terephthalate, polyethylene terephthalate, recycled plastic material or mixtures thereof, and wherein the filler material constitutes 50% to 80% by weight of the polymeric material.

18. The handle (12) according to any one of claims 1 to 4, wherein the fiber reinforcement material has a content of 1 g / cm³. 3 Up to 1.7 g / cm 3 The density.

19. The handle (12) according to claim 18, wherein the fiber reinforcement material has a content of 1.4 g / cm³. 3 The density.

20. The handle (12) according to claim 13, wherein the polymer material of the second component (22) has a content of 2 g / cm³. 3 Up to 3.5g / cm 3 The density.

21. The handle (12) according to claim 20, wherein the polymer material of the second component (22) has a content of 2.7 g / cm³. 3 The density.

22. The handle (12) according to claim 13, wherein the handle (12) further comprises a third component (24) that at least partially covers the core-connector unit (20) and / or the second component (22).

23. The handle (12) according to claim 22, wherein the material of the third component (24) is a thermoplastic elastomer material.

24. The handle (12) according to any one of claims 1 to 4, wherein the handle (12) is an oral care handle.

25. The handle (12) according to claim 24, wherein the handle (12) is a toothbrush handle.

26. A personal care tool (10) comprising a head (14) and a handle (12) according to any one of claims 1 to 25.

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