Cross-Reference to Related Applications

[0001] This application claims priority to U.S. Provisional Application No. 62/626,863 filed on February 6, 2018, which application is incorporated herein by reference in its entirety.

Field of the Invention

[0002] The present disclosure is directed generally to methods for manufacturing a brush head assembly with a protective coating or barrier applied around the exterior of a flexible material matrix that retains bristle tufts.

Background

[0003] The brush heads of both manual and power toothbrushes comprise bristles which are used to clean the teeth, tongue, and cheeks. In some toothbrushes, the bristles are stapled, or anchored into the neck portion of the brush head. In other toothbrushes, the bristles are secured to the head without staples, in methods commonly known as“anchor free tufting”. In some toothbrushes, the bristles are organized into bristle tufts contained within retention or carrier elements or otherwise secured to the brush head neck. The retention elements serve to secure the bristle tufts within the brush head. During manufacture, the bristle tufts are inserted into openings in the brush head neck and secured, or inserted into the hollow interior of the retention element, and the proximal portion of the bristles are melted together using a hot knife or heating plate or hot air to form a proximal end head portion to secure the bristles in the retention elements, which, along with the brush neck, are secured together by being surrounded with an injection molded flexible material, which is then allowed to cool in order to form the final brush head.

[0004] The soft flexible material is vulnerable to dimensional changes causing delamination or complete dissolution when exposed to oils, such as essential oils found in some organic toothpastes. As a result, the soft flexible material can peel and become adhered to surrounding elements. In addition, the bristle tufts can become stuck together, become loose, and/or fall out completely from the brush head. [0005] Accordingly, there is a need in the art for protecting the brush head from exposure to oils.

Summary of the Invention

[0006] The present disclosure is directed to inventive methods for manufacturing a brush head with secured bristle tufts and improved performance characteristics. Various embodiments and implementations herein are directed to manufacturing methods in which bristle tufts are affixed with or to retention elements and are then encapsulated within an injected flexible matrix material, resulting in a completed brush head. In other arrangements, the bristle tufts are secured directly to the brush head, and then encapsulated with an injected flexible matrix material. Using the various embodiments and implementations herein, cost- effective and efficient production of brush heads with secured bristle tufts is substantially improved.

[0007] The invention includes a flexible matrix material injected around a portion of the brush neck, retention elements (if present) and bristle tufts to retain the components in a brush head that can provide for varied purposeful mobility of bristle tufts/flexibility of the flexible matrix for improved and more complete teeth cleaning. Different materials or combinations of material can be selected for the flexible matrix material to achieve different performance characteristics. An additional protective coating is applied around the exterior of the flexible matrix material to provide improved performance characteristics, such as improved chemical impermeability. The brush heads disclosed and described herein can be used with any manual or power toothbrush device.

[0008] Generally, in one aspect, a method for manufacturing a brush head assembly is provided. The method includes providing a plurality of bristle tuft retention elements and a plurality of bristle tufts and inserting a respective bristle tuft into each of the bristle tuft retention elements. The method further includes securing a proximal end of each respective bristle tuft into each of the bristle tuft retention elements and positioning a platen portion of a neck of the brush head in relation to the proximal ends in a mold. The positioning of the platen portion of the neck defines a space in relation to the proximal ends for injection of a flexible material. The method further includes injecting the flexible material into the space in the mold to create a flexible material matrix that at least partially encompasses the platen, retention elements, and the proximal ends and coating at least a portion of an exterior of the flexible material matrix with a protective coating. The protective coating can provide increased resistance to one or more chemical compositions, oils or water. The protective coating can have a thickness within the range of 50-200 pm.

[0009] In various embodiments, the step of securing the proximal ends of the bristle tufts includes the step of applying heat to the proximal ends of the bristle tufts at a temperature sufficient to at least partially melt the proximal ends, or partially melt the proximal ends and a portion of the bristle tuft retention elements to create a proximal head portion.

[0010] In various embodiments, the flexible material matrix is made from a vulcanized thermoplastic elastomer (TPE-V or TPV), or a Polyether Block Amide (PEBA) material, a thermoplastic elastomer (TPE), a silicone or other flexible material.

[0011] In various embodiments, each of the neck, platen, and retention elements are made from a material with a higher elastic modulus value than the flexible material, such as a thermoplastic polymer such as polypropylene (PP), or a polyamide-acrylonitrile-butadiene- styrene blend (PA/ABS).

[0012] In various embodiments, the protective coating is a thermoplastic vulcanisate (TPV) material, an ultraviolet (UV) curable acrylate, a urethane-based heat curable coating, or a silicone.

[0013] In various embodiments, the neck further includes a gate for injection of the flexible material into the space.

[0014] Generally, in a further aspect, a method for manufacturing a brush head assembly is provided. The method includes providing a plurality of bristle tuft retention elements and a plurality of bristle tufts and inserting a respective bristle tuft into each of the bristle tuft retention elements. The method further includes securing a proximal end of each respective bristle tuft into each of the bristle tuft retention elements and positioning a platen portion of a neck of the brush head in relation to the proximal ends in a mold. The positioning of the platen portion of the neck defines a space in relation to the proximal ends for injection of a flexible material. The method further includes coating at least a portion of the mold with a protective coating and_injecting the flexible material into the space in the mold to create a flexible material matrix that at least partially encompasses the platen, retention elements, and the proximal ends and forming a layer on top of the flexible material matrix with the protective coating from the mold. In various embodiments, the coating is applied to an interior surface of the mold prior to injection of the flexible material. [0015] In various embodiments, the flexible material matrix is made from a vulcanized thermoplastic elastomer (TPE-V or TPV), or a Polyether Block Amide (PEBA) material, a thermoplastic elastomer (TPE), a silicone or other flexible material.

[0016] In various embodiments, each of the neck, platen, and retention elements are made from a material with a higher elastic modulus value than the flexible material, such as a thermoplastic polymer such as polypropylene (PP), or a polyamide-acrylonitrile-butadiene- styrene blend (PA/ABS).

[0017] In various embodiments, the protective coating is a thermoplastic vulcanisate (TPV) material, an ultraviolet (UV) curable acrylate, a urethane-based heat curable coating, or a silicone.

[0018] In various embodiments, the neck further includes a gate for injection of the flexible material into the space.

[0019] Generally, in another aspect, a brush head for a toothbrush is provided. The brush head includes a neck having a platen portion, a plurality of bristle tufts, each of which comprises a plurality of bristle strands, and a plurality of retention elements, each configured to receive at least one of the plurality of bristle tufts. After the bristle tufts are inserted into the retention elements, the proximal ends of the bristle tufts are secured into the retention elements. The brush head further includes a flexible material matrix formed by injection molding a flexible material around least a portion of the brush neck platen, the plurality of retention elements, and the proximal ends to secure the components together and a protective coating around at least a portion of an exterior of the flexible material matrix.

[0020] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein.

[0021] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter. Brief Description of the Drawings

[0022] In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.

[0023] FIGS. 1 is a schematic representation of a side view of a brush head assembly in accordance with an embodiment.

[0024] FIG. 2 is a schematic representation of a reverse view of a brush head assembly in accordance with an embodiment.

[0025] FIG. 3A is a flowchart of a method for manufacturing a brush head assembly with a protective coating or barrier in accordance with an embodiment.

[0026] FIG. 3B is a flowchart of a method for manufacturing a brush head assembly with a protective coating or barrier in accordance with an embodiment.

[0027] FIGS. 4A-4C are schematic representations of a method for manufacturing a brush head assembly with bristle tufts retained within a flexible material matrix in accordance with an embodiment.

Detailed Description of Embodiments

[0028] The present disclosure describes various embodiments of a method for manufacturing a brush head assembly with bristle tufts retained within a flexible material matrix such that the brush head assembly is resistant or immune against oils. More generally, Applicants have recognized and appreciated that it would be beneficial to provide a brush head formed from a flexible matrix, which can be beneficial to a brush head’s function, especially in powered toothbrush devices. A particular goal of utilization of certain embodiments of the present disclosure is the ability to efficiently manufacture brush heads with improved retention of the bristle tufts and other components while providing good brushing performance.

[0029] In view of the foregoing, various embodiments and implementations are directed to a method in which a bristle tuft is affixed to or within a retention element or directly to a brush head neck, and is then embedded within a flexible material matrix. The bristle tuft is inserted into the retention element and is secured to or within the retention element. Alternatively, the bristle tufts are attached directly in or to the brush head neck by means of holes, and/or other securing methods, such as melting, gluing, laser welding or other securing methods. As yet another alternative, a retaining head portion is created on the bristle tuft which is then unable to pass through the retention element. The bristle tuft and retention element (if present) are then embedded within a flexible material matrix to form the brush head. The flexible material matrix is then coated with a protective coating or barrier to prevent the matrix from experiencing dimensional changes when exposed to oils or the slow down the diffusion of oils into the matrix.

[0030] Brush Head Assembly

[0031] Referring to FIG. 1, in one embodiment, a schematic representation of a brush head assembly 100 is provided. The brush head includes a neck 40, which can be coupled to any manual brush shaft, or, more preferably, to any actuator and drive shaft (not shown) made or suitable for oral care devices now known or to be developed. The brush head also includes a plurality of bristle tufts 21, each of which comprises a plurality of bristle strands. Each bristle tuft includes a proximal end and a free end, where the proximal end of each bristle tuft is retained within the brush head assembly 100.

[0032] According to an embodiment as shown in FIG. 1, each bristle tuft 21 is retained within a hollow portion of a retention element 50. The proximal end of the bristle tuft and at least a portion of the retention elements and the portion of the neck that is the platen 42 are encapsulated within an injection molded flexible material matrix 30. In another embodiment (not shown), the proximal end of the bristle tufts 21 are secured directly in or to the platen 42 by means of securing the ends into holes in the neck, or melting, gluing, laser welding or other securing method. According to an embodiment, the flexible material matrix 30 is preferably made from a vulcanized thermoplastic elastomer (TPE-V or TPV), a Polyether Block Amide (PEBA) material, a thermoplastic elastomer (TPE), silicone, or any other material suitable for injection molding that remains flexible after curing. The neck 40, platen 42, and the retention elements 50 are preferably made from a material with a higher elastic modulus value than the flexible material matrix 30, typically a thermoplastic polymer such as polypropylene (PP), or a polyamide-acrylonitrile -butadiene-styrene blend (PA/ABS). The flexible material matrix 30 includes an additional protective coating applied to the exterior of the flexible material matrix 30 to provide improved material performance, such as increased resistance to one or more chemical compositions, oils, or water, for example, as further described below. [0033] Referring to FIG. 2, a reverse schematic representation of a brush head assembly 100 is provided. One or more gates 41 is shown on the back side of the neck 40. This gate 41 is used for the injection molding of the flexible material matrix 30, as described below.

[0034] Many other embodiments of brush head assembly 100 are possible, including other configurations of neck 40, platen 42, bristle tufts 21, retention elements 50 (if used), and/or flexible material matrix 30.

[0035] Methods of Brush Head Manufacture

[0036] Referring to FIG. 3A, in one embodiment, is a method 200 for manufacturing one or more of the various brush head embodiments and implementations described or otherwise envisioned herein. In step 210 of the method of manufacture depicted in FIG. 3 A, a plurality of retention elements 50 are provided. Retention elements 50 can be of various shapes, sizes, and/or configurations described or otherwise envisioned herein. For example, the plurality of retention elements 50 can be the same size and shape, or multiple different sizes and shapes.

[0037] At step 220 of the method, a bristle tuft 21 (which comprises a plurality of bristle strands) is inserted into each of the plurality of retention elements 50. Each of the bristle tufts 21 includes a proximal end and a free end, with the proximal end being inserted into the retention element.

[0038] At step 230 of the method, the bristle tufts are secured in the retention elements. In one arrangement, heat is applied to the proximal end of the plurality of bristle tufts 21 to create a melted proximal end head portion 26 that secures the bristle tufts in the retention elements. Proximal end head portion 26 is the melted ends of the bristle tuft 21, or the melted ends of the bristle tufts and at least a portion of the retention elements, depending on the composition, and therefore the melting point, of the materials used for each component. This proximal end head portion is of a sufficient size that it cannot move back through the retention element, thereby securing the bristle tuft in the hollow ring of the retention element.

[0039] In step 240 of method 200 depicted in FIG. 3A, the brush head neck 40 is positioned to put the platen 42 portion of the neck in the proper location in relation to the retention elements 50 with the bristle tufts 21 inserted, as shown in FIG. 4A. Typically, the platen 42 is positioned just above the proximal end head portion 26 of the bristle tufts 21 in the retaining elements 50. Platen 42 can be properly positioned using a mold, for example, or other positioning mechanism. This creates a space 92 into which the flexible material can be injected. [0040] In step 250 of the method, a flexible material is molded, typically by means of injection molding, into the space 92 between and around the platen 42, the head portion 26 of the bristle tufts, and the retention elements 50. According to an embodiment, as shown in FIG. 4B, neck 40, platen 42 of the brush head, and the retention elements and bristle tufts are held in a mold while the flexible material is injected into the space 92. As shown in FIG. 2, neck 40 comprises one or more gates 41 that allows the molten flexible material to be injected into the cavity of the mold. The molded flexible material forms a flexible material matrix 30, as shown in FIGS. 4B and 4C. The neck 40, platen 42, and the retention elements 50 are preferably made from a material with a higher elastic modulus value than the flexible material matrix 30, typically a thermoplastic polymer such as polypropylene (PP), or a polyamide-acrylonitrile-butadiene-styrene blend (PA/ABS).

[0041] As shown in step 260 of FIG. 3 A and in FIG. 4C, an additional protective coating 60 is applied to all or a portion of the exterior of the flexible material matrix 30 to provide improved material performance, such as increased resistance to one or more chemical compositions, oils, or water, for example. The protective coating, which can be transparent preferably, can be sprayed or over molded on the flexible material matrix 30 such that the protective coating forms a thin, uniform coating on all or a portion of the exterior of the flexible material matrix 30. The protective coating can have a thickness that is greater than 50 pm and less than 200 pm.

[0042] Various materials can be used to provide the protective coating, depending on the desired performance enhancement. For example, the coating could be a thermoplastic vulcanisate (TPV) material, a UV curable acrylate, a silicone, a heat curable (e.g., urethane- based) coating, or other coatings applied over the exterior of the flexible material matrix to improve chemical resistance to oils, water, and other chemicals. The composition of the protective coating must be compatible with the composition of the flexible material matrix to which it is being applied to ensure good bonding.

[0043] Referring to FIG. 3B, in one embodiment, is a method 300 for manufacturing one or more of the various brush head embodiments and implementations described or otherwise envisioned herein. Steps 310, 320, 330, and 340 are the same as steps 210, 220, 230, and 240, respectively, in the method 200 in FIG. 3 A. However, as shown in step 350 of FIG. 3B, an additional protective coating 60 can be applied to all or a portion of the interior surface of the mold prior to injecting the flexible material. The protective coating can be sprayed or otherwise applied to the interior of the mold in step 350. The protective coating can be various materials as described above, depending on the desired performance enhancement. For example, the coating could be a thermoplastic vulcanisate (TPV) material, a UV curable acrylate (e.g., a polyurethane acrylate UV coating), a heat curable (e.g., urethane-based) coating, a silicone, or other coatings applied over the exterior of the flexible material matrix to improve chemical resistance to oils, water, and other chemicals. The composition of the protective coating must be compatible with the composition of the flexible material matrix to which it is being applied to ensure good bonding.

[0044] In step 360 of the method of FIG. 3B, a flexible material is injected into the mold so that the protective coating on the inside of the mold adheres to the flexible material as the flexible material is molded. The protective coating 60 adheres to the exterior surface of the flexible material matrix 30. The flexible material is molded, typically by means of injection molding, into the space 92 between and around the platen 42, the head portion 26 of the bristle tufts, and the retention elements 50. According to an embodiment, as shown in FIG. 4B, neck 40, platen 42 of the brush head, and the retention elements and bristle tufts are held in a mold while the flexible material 30 is injected into the space 92. As shown in FIG. 2, neck 40 comprises one or more gates 41 that allow the molten flexible material to be injected into the cavity of the mold. The molded flexible material forms a flexible material matrix 30 with a protective coating adhered thereto, as shown in FIG. 4C. The neck 40, platen 42, and the retention elements 50 are preferably made from a material with a higher elastic modulus value than the flexible material matrix 30, typically a thermoplastic polymer such as polypropylene (PP), or a polyamide-acrylonitrile-butadiene-styrene blend (PA/ABS).

[0045] The protective coating 60 described or otherwise envisioned herein can also be applied to the flexible material using masks or caps to protect the retention rings and bristles from being coated. The

[0046] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms.

[0047] The indefinite articles“a” and“an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean“at least one.”

[0048] The phrase“and/or,” as used herein in the specification and in the claims, should be understood to mean“either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e.,“one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the“and/or” clause, whether related or unrelated to those elements specifically identified.

[0049] As used herein in the specification and in the claims,“or” should be understood to have the same meaning as“and/or” as defined above. For example, when separating items in a list,“or” or“and/or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as“only one of’ or“exactly one of,” or, when used in the claims,“consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term“or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e.“one or the other but not both”) when preceded by terms of exclusivity, such as“either,”“one of,”“only one of,” or “exactly one of.”

[0050] As used herein in the specification and in the claims, the phrase“at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase“at least one” refers, whether related or unrelated to those elements specifically identified.

[0051] It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited.

[0052] In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases“consisting of’ and“consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively. [0053] While several inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the inventive teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.