Toothbrush with light transmissive handle

A toothbrush handle includes a support structure formed of clarified polypropylene and a body formed of thermoplastic elastomer disposed on the support structure. The support structure includes a web having a thickness in a first direction orthogonal to an axis of the toothbrush handle of less than 2 millimeters and at least one rib depending from the web and having a thickness in a second direction, orthogonal to the axis and angled relative to the first direction, of less than about 2 millimeters. The body at least partially covers the web and the at least one rib. The handle has a light transmissivity of greater than 40% through a portion of the handle at which the body covers the web and the at least one rib.

BACKGROUND

Functionality and aesthetics play significant roles in driving consumer demand for manual toothbrushes. Clear, or transparent, toothbrushes, especially toothbrush handles, provide a unique and oftentimes desirable aesthetic. Conventional clear toothbrushes are generally made from polymers or acrylics that maintain clarity at standard toothbrush dimensions. However, those materials tend to be more expensive than polymers generally used in manual toothbrush manufacture and may slow manufacturing throughput. For example, copolyesters have been used to make clear toothbrushes, but such materials have many drawbacks over conventionally-used polymers. Notably, copolyesters take a relatively long time to cure, lengthening the production time. Moreover, copolyesters are generally more expensive than conventional materials.

Accordingly, there is a need in the art for a toothbrush with desirable aesthetics, such as a transparent or semi-transparent appearance, but that is readily manufactured.

BRIEF SUMMARY

In aspects of this disclosure, a toothbrush handle includes a support structure formed of clarified polypropylene, the support structure comprising a web having a thickness in a first direction orthogonal to an axis of the toothbrush handle of less than 2 millimeters and at least one rib depending from the web and having a thickness in a second direction, angled relative to the first direction, of less than 2 millimeters and a body formed of thermoplastic elastomer disposed on the support structure to at least partially cover the web and the at least one rib, wherein the handle has a light transmissivity of greater than 40% through a portion of the handle at which the body covers at least a portion of the web and the at least one rib.

In one or more additional aspects, in a toothbrush handle as described in the preceding paragraph, the support structure further comprises a frame defining a void and the web extends across at least a portion of the void.

In one or more additional aspects, in a toothbrush handle as described in any of the preceding paragraphs, the at least one rib depends orthogonally from the web.

In one or more additional aspects, in a toothbrush handle as described in any of the preceding paragraphs, the web and the at least one rib extend along the axis from a position proximate an end of the handle toward a neck of the handle.

In one or more additional aspects, in a toothbrush handle as described in any of the preceding paragraphs, the light transmissivity is measured substantially along the first direction or the second direction.

In additional aspects of this disclosure, a toothbrush includes a handle and a head disposed at a distal end of the handle, wherein the handle comprises a plurality of support structures extending generally along a longitudinal axis of the handle from a position proximate a proximal end axially opposite the distal end toward the head, each of the support structures having a thickness of less than 2 millimeters in a direction orthogonal to the longitudinal axis.

In one or more additional aspects, in a toothbrush as described in the preceding paragraph, the plurality of support structures comprise a plurality of spaced-apart elongate ribs.

In one or more additional aspects, in a toothbrush as described in any of the preceding paragraphs, the support structures further comprise a web and the plurality of spaced-apart elongate ribs extend from a surface of the web.

In one or more additional aspects, in a toothbrush as described in any of the preceding paragraphs, the support structures are formed of a material having a light transmissivity of at least 85% determined using ASTM D1003.

In one or more additional aspects, in a toothbrush as described in any of the preceding paragraphs, the handle further comprises a body covering the support structures.

In one or more additional aspects, in a toothbrush as described in any of the preceding paragraphs, the body is formed from a material having a light transmissivity of at least 85% determined using ASTM D1003.

In one or more additional aspects, in a toothbrush as described in any of the preceding paragraphs, the handle has a light transmissivity of greater than 40% through a portion of the handle comprising the body covering the support structures measure substantially along the direction orthogonal to the longitudinal axis.

In additional aspects of this disclosure, a handle for an implement includes a support structure comprising at least one support member extending generally along a longitudinal axis of the handle, the support structure being formed of a first material, and a body disposed on the support structure to cover at least part of the at least one support member, the body being formed of a second material, wherein the handle is at least translucent along a sight line passing through the body and the support structure orthogonal to the longitudinal axis.

In one or more additional aspects, in a handle as described in the preceding paragraph, both the first material and the second material have a light transmissivity of at least 85% determined using ASTM D1003.

In one or more additional aspects, in a handle as described in any of the preceding paragraphs, at least one of the first material is a clarified polypropylene or the second material is a thermoplastic elastomer.

In one or more additional aspects, in a handle as described in any of the preceding paragraphs, the at least one support structure has a thickness in the direction orthogonal to the longitudinal axis of less than 2 millimeters.

In one or more additional aspects, in a handle as described in any of the preceding paragraphs, the at least one elongate support structure comprises a web and a plurality of ribs extending from a surface of the web.

In one or more additional aspects, in a handle as described in any of the preceding paragraphs, the support structure comprises a plurality of elongate ribs angled relative to each other to form a corrugated structure.

In one or more additional aspects, in a handle as described in any of the preceding paragraphs, the at least translucent portion has a visible light transmittance of at least 40%.

In one or more additional aspects, in a handle as described in any of the preceding paragraphs, the body is overmolded onto the support structure.

DETAILED DESCRIPTION

This disclosure relates generally to handles for implements, and more specifically to configurations of a handle for an oral care implement, such as a toothbrush handle. The following detailed description may generally refer to embodiments of a handle as part of a toothbrush, but this disclosure is not limited to use of a handle as a toothbrush handle. Other implements, including but not limited to oral care implements, may incorporate features of this disclosure. In particular implementations, handles according to this disclosure may include transparent or translucent sections.

FIGS. 1 and 2illustrate a toothbrush100according to a first implementation of this disclosure. The toothbrush100generally includes a handle102, a head104(which may support bristles, not shown) disposed of the distal end of the handle102and a neck portion106generally between the handle102and the head104. As illustrated, the handle has a generally elongate shape, extending along an axis108. This disclosure is not limited to the shape and/or size of the toothbrush100illustrated inFIGS. 1 and 2. In alternative implementations, one or more of the handle102, head104, and/or neck106may have different shapes, sizes, orientations, and/or the like. Additional features may also be incorporated into the toothbrush or disposed on the toothbrush.

As illustrated, the handle102generally includes a frame110, which provides an outer periphery of the handle102and defines an inner void or opening. A web112extends between sections of the frame110, generally along the direction of the axis108, and expands across the void. In this embodiment, the web112occludes the void completely, although in other embodiments, the web112may fill less than the entire void. For example, holes (not illustrated) may be formed through the web112to aid in some manufacturing processes, an example of which will be provided below.

As also illustrated inFIGS. 1 and 2, a plurality of elongate fins or ribs114(illustrated as a central rib114-1and two outer ribs114-2) depend from the web112and extend generally parallel to the axis108from a position proximate an end opposite the head104toward the head104. In this example, the ribs114extend perpendicularly from opposite sides of the web112. (As used herein, “perpendicular” and similar terms should be understood to include slight variations, such as things that are “substantially perpendicular.”) As will be appreciated, the ribs114may extend at angles other than 90-degrees. Although three ribs114are illustrated as extending from each side of the web112, more or fewer ribs114may alternatively be provided on one or both sides of the web112. As also illustrated inFIG. 1, the ribs114may extend different lengths, i.e., along the axis108. In the illustrated example, the central rib114-1is longer than the other ribs114-2, extending further along the neck106, closer to the head104. In other implementations, all of the ribs114may be the same length, or they could all be different lengths. The ribs114may each have the same height relative to the web112or the height may vary from rib to rib. For example, the central rib114-1may be taller than the outer ribs114-2to provide a crowned or similar profile across the width of the toothbrush100, as shown inFIG. 2. Alternatively, or in addition, the height of one or more of the ribs114may vary along its length. As illustrated inFIG. 1, the ribs may be straight along their length or they may be contoured. In this example, the central rib114-1is generally straight, extending parallel to the axis108of the toothbrush100, whereas the outer ribs114-2on either side of the central rib114-1more closely follow the contour of the frame110. More specifically, at the end of the handle102opposite the head104, the ribs are generally closer to each other with the outer ribs114gradually tapering away from the central rib before tapering back towards the central rib proximate the neck106. As will be appreciated by those having skill in the art with the benefit of this disclosure, the number, height, contour, and other attributes of the ribs may be varied to provide different aesthetic and functional benefits.

InFIGS. 1 and 2, a thickness of each of the web112and the ribs114may be minimized. InFIG. 2, the thickness of the web112is indicated as twand the thickness of the ribs114is indicated as tr. In this example, the thickness twis measured in a first direction orthogonal to the axis108in and the thickness tris measured in a second direction, also orthogonal to the axis108, but angled (e.g., by 90-degrees) relative to the first direction. By minimizing their thicknesses, the web112and the ribs114may be substantially transparent when viewed along a line of sight parallel to the first and second directions, respectively. More specifically, with some materials, as twdecreases, more light incident on the web will be transmitted through the web112. Likewise, as trdecreases, more light incident on each of the ribs will be transmitted through the ribs114.

In one example implementation, the toothbrush100may be formed from a material having a light transmittance of 85% or more (determined per ASTM D1003). Clarified polypropylene is an example of such a material. Clarified polypropylene provides increased visible light transmission over non-clarified polypropylene, particularly at decreased thicknesses. Thus, in the embodiment illustrated inFIGS. 1 and 2, by minimizing the thickness of the web112and the ribs114, the structure created by the web112and the ribs114(i.e., in the void) allows more light through than the relatively thicker areas, e.g., the outer frame110and the head104. Along viewing angles normal to the web and the ribs, the structure is substantially transparent. In some implementations, the web112and the ribs114have a thickness of less than 2 millimeters and in other embodiments less than 1 millimeter to achieve better light transmittance. As noted above, the thickness of the web112and the ribs114will affect the light transmission properties of the toothbrush. Other factors, such as the type and amount of clarifier used in the polypropylene and/or other additives, such as dyes or the like, may also affect light transmissivity.

Some presently preferred embodiments allow for at least 80% transmittance of light at wavelengths of 410-800 nanometers (i.e., in the visible light spectrum) through portions of the toothbrush100. For instance, along a sight line normal to the web, the toothbrush will have a transmittance of 80% or greater. For purposes of this disclosure, as long as one wavelength in the visible light range has greater than 80% transmittance, the toothbrush100, is substantially transparent. In other embodiments, toothbrushes in accordance with this disclosure will have a light transmittance of at least 85-90% for light at a wavelength of 410-800 nanometers. For purposes of this disclosure, as long as one wavelength in the visible light spectrum has transmittance greater than a designated amount at any location on the toothbrush, the toothbrush is considered to have a transmittance of at least that amount in the visible light spectrum. Some embodiments allow for at least 40% transmittance of light in the visible light spectrum through substantially all portions of the toothbrush at angles normal to the axis.

Light transmissivities described herein may be measured using a spectrophotometer using known techniques. For example, ASTM D1003 describes a technique for measuring light transmissivity through transparent plastics. Although that test is intended for materials having a standard size and shape, similar techniques may be used to measure transmissivity through the toothbrush.

The material may also be chosen to limit haze. Haze may also be determined using ASTM D1003, and the material used to manufacture the toothbrush100may have a haze value of less than 25%.

A number of benefits may be realized by using the clarified polypropylene over conventional clear acrylics or other materials. For instance, clarified polypropylene is generally cheaper than materials conventionally used to make clear parts. Moreover, manufacturing and handling the clarified polypropylene may be easier. Some conventional materials would require longer curing times to form a part like a toothbrush, thus increasing production throughput. Moreover, polypropylene may be readily amenable to further processing. In the example ofFIG. 1, the entire toothbrush100is formed as a unitary piece. When that piece is formed of clarified polypropylene, post-processes, such as application of bristles to the head104, may be done using conventional techniques.

In the example ofFIGS. 1 and 2, the toothbrush100may be a single, unitary part, e.g., formed from a single mold from a single material—clarified polypropylene in one example. More light will be transmitted through the web112and the ribs114(along a sight line normal to such features, respectively) than through the frame110and the head104, because the frame and the head are substantially thicker. Thus, the toothbrush100will appear substantially transparent along some sight lines, e.g., sight lines normal to the web, and more translucent along other sight lines, e.g., sight lines at other angles, through thicker areas, or through multiple features. In other embodiments, the thickness of the outer frame110could be decreased, e.g., to appear more like another rib114, which could result in even greater light transmission along sight lines normal to the ribs, passing through the outer frame. Such a design may be less comfortable for a user, but could provide a more light-transmissive aesthetic.

In certain embodiments, the head104may comprise a plate having a plurality of holes formed therethrough, and tooth cleaning elements may be mounted to the plate within the holes. This type of technique for mounting the tooth cleaning elements to the head104via a head plate is generally known as anchor free tufting (AFT). Specifically, in AFT a plate or membrane is created separately from the head104. The tooth cleaning elements (such as bristles, elastomeric elements, and combinations thereof) are positioned into the head plate so as to extend through the holes of the head plate. The free ends of the tooth cleaning elements on one side of the head plate perform the cleaning function. The ends of the tooth cleaning elements on the other side of the head plate are melted together by heat to be anchored in place. As the tooth cleaning elements are melted together, a melt matte is formed, which is a layer of plastic formed from the collective ends of the tooth cleaning elements that connects the tooth cleaning elements to one another on one side of the head plate and prevents the tooth cleaning elements from being pulled through the tuft holes.

After the tooth cleaning elements are secured to the head plate, the head plate is secured to the head104such as by ultrasonic welding. When the head plate is coupled to the head104, the melt matte is located between a lower surface of the head plate and a floor of a basin of the head104in which the head plate is disposed. The melt matte, which is coupled directly to and in fact forms a part of the tooth cleaning elements, prevents the tooth cleaning elements from being pulled through the holes in the head plate thus ensuring that the tooth cleaning elements remain attached to the head plate during use of the oral care implement100.

In another embodiment, the tooth cleaning elements may be connected to the head104using a technique known in the art as AMR. In this technique, the handle is formed integrally with the head plate as a one-piece structure. After the handle and head plate are formed, the bristles are inserted into holes in the head plate so that free/cleaning ends of the bristles extend from the front surface of the head plate and bottom ends of the bristles are adjacent to the rear surface of the head plate. After the bristles are inserted into the holes in the head plate, the bottom ends of the bristles are melted together by applying heat thereto, thereby forming a melt matte at the rear surface of the head plate. The melt matte is a thin layer of plastic that is formed by melting the bottom ends of the bristles so that the bottom ends of the bristles transition into a liquid, at which point the liquid of the bottom ends of the bristles combine together into a single layer of liquid plastic that at least partially covers the rear surface of the head plate. After the heat is no longer applied, the melted bottom ends of the bristles solidify/harden to form the melt matte/thin layer of plastic. In some embodiments, after formation of the melt matte, a tissue cleaner is injection molded onto the rear surface of the head plate, thereby trapping the melt matte between the tissue cleaner and the rear surface of the head plate. In other embodiments, other structures may be coupled to the rear surface of the head plate to trap the melt matte between the rear surface of the head plate and such structure without the structure necessarily being a tissue cleaner (the structure can just be a plastic material that is used to form a smooth rear surface of the head, or the like, and the structure can be molded onto the rear surface of the head plate or snap-fit (or other mechanical coupling) to the rear surface of the head plate as desired).

Of course, techniques other than AFT and AMR can be used for mounting tooth cleaning elements to the head104, such as widely known and used stapling/anchoring techniques or the like. In such embodiments the head plate may be omitted and the tooth cleaning elements may be coupled directly to the head104. Furthermore, in a modified version of the AFT process discussed above, the head plate may be formed by positioning the tooth cleaning elements within a mold, and then molding the head plate around the tooth cleaning elements via an injection molding process. However, it should be appreciated that certain of the bristle tufts disclosed herein cannot be adequately secured to the head using staple techniques, and one of AFT or AMR is therefore use for securing such bristle tufts (i.e., the conical tufts described below) to the head.

Although described herein above with regard to using AFT, in certain embodiments any suitable form of cleaning elements and attachment may be used in the broad practice of this invention. Specifically, the tooth cleaning elements of the present invention can be connected to the head104in any manner known in the art. For example, staples/anchors or in-mold tufting (IMT) could be used to mount the cleaning elements/tooth engaging elements. In certain embodiments, the invention can be practiced with various combinations of stapled, IMT, AMR, or AFT bristles. Alternatively, the tooth cleaning elements could be mounted to tuft blocks or sections by extending through suitable openings in the tuft blocks so that the base of the tooth cleaning elements is mounted within or below the tuft block.

Although not illustrated herein, in certain embodiments the head104may also include a soft tissue cleanser coupled to or positioned on its rear surface. An example of a suitable soft tissue cleanser that may be used with the present invention and positioned on the rear surface of the head104is disclosed in U.S. Pat. No. 7,143,462, issued Dec. 5, 2006 to the assignee of the present application, the entirety of which is hereby incorporated by reference. In certain other embodiments, the soft tissue cleanser may include protuberances, which can take the form of one or more ridges (elongated transverse, longitudinal, angled), nubs, or combinations thereof. Of course, the invention is not to be so limited and in certain embodiments the oral care implement100may not include any soft tissue cleanser.

Generally, inFIGS. 1 and 2the web112and the ribs114may act as support members that collectively form a support structure. The support structure preferably provides stability and a degree of rigidity to the handle102for comfortable and effective manual manipulation.FIGS. 3 and 4illustrate another embodiment of this disclosure, in which the support structure supports a body, which may be molded over a portion of the handle.

More specifically,FIGS. 3 and 4illustrate a toothbrush300that is substantially the same as the toothbrush100(and the same reference numerals are used to identify common components) and further includes a body302formed over a portion of the handle102and neck106. In this example, the body302is disposed to completely cover the web112and the ribs114, on both sides (i.e., the top and bottom) of the toothbrush. The body may be formed to take generally any outer shape and profile, and the dimensions of the body may vary at different positions along the toothbrush.

As noted above, some or all of the outer frame110, web112, and ribs114may act as a support structure to provide rigidity to the toothbrush300, whereas the body302may be chosen to provide a different aesthetic, e.g. to mask the ribs, and/or to provide a different manual gripping surface, e.g., to alter control, comfort, and/or handling. For example, a material having a hardness value of between about 15 and about 90 Shore-A may be selected for its tactile comfort. A low-haze material may also be selected, for its visual aesthetic. For example, a material having a haze value of less than 10% and more preferably less than 5% may be chosen as the material for the body.

While a number of conventional materials may be used for the body, in some embodiments the body302is made from a material having a light transmittance of 85% or more (determined per ASTM D1003). By way of non-limiting example, the body302may be made from a thermoplastic elastomer (TPE) or thermoplastic polymer. TPE having a light transmittance of 90% or higher (determined per ASTM D1003) is commercially available. Moreover, TPE can be readily manufactured, such as through conventional molding, e.g., injection molding, processes, and some TPEs have a haze value of less than about 5%. A suitable TPE for the body302may be based on polyolefin-based polymers, styrene block copolymers, and/or a blend of the two.

As will be appreciated, when a light transmissive material is used for the body, such as the TPE described above, the overall effect will be a handle that transmits visible light, because both the underlying support structure100and the body302transmit visible light. The transmissivity of visible light will vary along the toothbrush, e.g., depending upon the thicknesses of the body and the support structure. For example, visible light passing through the neck of the toothbrush along a line of sight normal to the web will have a relatively high transmissivity, and that portion of the toothbrush may be substantially transparent. In contrast, less visible light will pass through the toothbrush along a line of sight that passes through the outer frame110and the body302. However, because the toothbrush300is made from two materials, each having light transmissivity of 85% or higher, some light will pass through the structures made of these materials at conventional toothbrush sizes. Toothbrushes made according to aspects of this disclosure may allow for at least 40% transmittance of light, more preferably 50% transmittance of light, at wavelengths of 410-800 nanometers (i.e., in the visible light spectrum) along substantially any sight line normal to the axis and passing through both the support structure and the body.

The toothbrushes100,300described above may be manufactured using conventional molding techniques, including but not limited to injection molding. In one example implementation, the toothbrush100may be formed in a single mold, as a single shot. In another embodiment, the toothbrush100may be formed in two shots, for example, a first shot to create the support structure and a second shot to create the relatively thicker features, e.g., the outer frame110and the head104. In this example, the second shot may be a different material than the first shot, which may provide additional functionality. For instance, the second shot could be an opaque material, in which case only the area in the void would be at least translucent. Such an arrangement may provide a different aesthetic.

When the body302is included, as in the toothbrush300, the material comprising the body may be overmolded on the toothbrush100as support structure. In some embodiments, the body302may be formed in a single shot. As one way to promote such a process, holes or the like may be formed in the web114, e.g., to allow the material forming the body to pass through to both sides (i.e., the top and bottom) of the toothbrush. In other embodiments, the body302may be formed as two or more shots, e.g., a first shot for the body on a first side of the web112and a second shot for the body on the other side of the web.

According to embodiments of this disclosure, it may be desirable to control the finish on external surfaces of the toothbrush, e.g., to reduce haze. In some examples the TPE body302may have a polished surface finish, such as an SPI-A1 or SPI-A2 finish. Such a finish may be achieved by controlling aspects of the molding process. Alternatively, a light surface texture may be applied on the tool to aid in demolding while maintaining a high quality surface. In some embodiments, ejector pins may be staged in the mold, e.g., along the axial direction of the toothbrush, to promote part removal. Ejectors or knock out pins may iteratively de-mold the part along the axial length, to break any vacuum formed between the part and the mold, essentially peeling the mold from the part. Bristles and/or other cleaning implements may also be integrated into the toothbrush100,300after molding.

The body302preferably has good light transmission properties and may advantageously be chemically compatible with the support structure. The body302may also take any of a number of shapes, profiles, or appearances. For example,FIG. 5shows a cross section of another example toothbrush500in which a body502is formed to completely encapsulate the support structure. Unlike the body302described above, which was formed laterally between the outer frame110to leave a portion of the outer frame110exposed, the body502leaves none of the outer frame110exposed. In an alternative to this example, the outer frame110may be manufactured to be thinner, e.g., to have a thickness comparable to the ribs, to enhance light transmission through the outer frame. In such an example, the toothbrush may be transparent or semi-transparent when viewed from a side, as well as when viewed from the top or bottom.

Although not illustrated inFIG. 5, the body502may extend axially along the toothbrush500any distance. For example, the body502may be formed only over the portion of the handle that includes the web and/or ribs or it could extend any distance beyond. In still other embodiments, the ribs may be partially exposed. Moreover, the body502may be formed such that some or all of the support structure, e.g., the outer frame, is exposed proximate the end of the toothbrush opposite the head, or such that all the outer frame is encapsulated.

Other configurations of the toothbrush100,300,500also are contemplated. For example,FIG. 6illustrates a toothbrush600having a body602disposed on a support structure having a cross section different from those described above. The support structure generally includes two (e.g., top and bottom) planar members604,606connected by longitudinally extending ribs608. The surfaces604,606and the extending ribs608form a support structure for the body602, similar to the embodiments discussed above. As with previously described embodiments, the surfaces604,606and the extending ribs608preferably are thin enough to allow light transmission therethrough. When clarified polypropylene is used to form the support structure, the surfaces604,606and extending ribs608may be about two millimeters thick or thinner. In other embodiments, the thickness may be one millimeter or less.

Although the body602is illustrated as encapsulating the support structure, in other embodiments the body may cover less. For example it may be formed only on the top and/or bottom surfaces of the structure, as in the toothbrush300, described above. In some embodiments, the surfaces604,606and ribs608may be disposed between an outer frame.

Another example embodiment is illustrated inFIG. 7. Like other embodiments,FIG. 7shows a cross-section of a handle700. A support structure in this embodiment includes a plurality of ribs702extending between an outer frame704. The outer frame may take the form of the outer frame110described above. The ribs702in this example constitute a plurality of support members that together form a corrugated profile. As with embodiments described above, a body may be disposed over some or all of the support structure. Moreover, the outer frame may not be necessary.

In each of the examples provided, the support structure includes one or more relatively thin-walled sections, which have higher light transmissivity than relatively thicker sections. When a light-transmissive body is provided over the support structure, the result is a handle having improved light transmission. Although an amount of light transmission will vary along the handle (e.g., based on material thicknesses), some example implementations may allow for at least 40% transmittance of light, more preferably 50% transmittance of light, at wavelengths of 410-800 nanometers (i.e., in the visible light spectrum) along substantially any sight line passing through both the support structure and the body.

Although example embodiments have been described in language specific to the structural features and/or methodological acts, the claims are not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as illustrative forms of implementing the example embodiments.