Razor blades with aluminum magnesium boride (AlMgB14)-based coatings

This invention relates to a novel application of hard, low friction aluminum magnesium boride (AlMgB14, also known as BAM) based ceramic coatings to surfaces of razor components and in particular to blade edges of razor blades. On razor blade edges, these coatings may elevate blade performance, while also simplifying the manufacturing process.

FIELD OF THE INVENTION

The apparatus relates generally to razor blades, and more particularly, to novel coatings on razor blade edges.

BACKGROUND OF THE INVENTION

Current razor blades typically include a sharpened substrate, such as stainless steel, a hard coating(s) to optimize edge strength, tip shape, wear resistance, etc. layered on top of the stainless steel and a soft coating(s) generally of polymeric material, such as telomer, layered on top of the hard coating(s) to impart lubricity.

It is generally known that the combination of the sharpened blade profile and the hard and lubricious coatings generally define the performance of the blade element. Generally, of interest are coating options which may improve a blade element's hard coating performance and/or increase blade lubricity.

It would be desirable to optimize blade coatings and/or steps required in the blade production, while maintaining or improving blade performance.

SUMMARY OF THE INVENTION

In accordance with the invention, a razor blade apparatus includes a sharpened substrate having at least one layer of BAM material disposed thereon. In a preferred construction of the present invention, the at least one layer of BAM material is directly disposed on the sharpened substrate. One or more interlayers may be disposed between the BAM layer and the sharpened substrate and one or more overcoat layers may be disposed on top of the BAM layer. The interlayer and overcoat layer include an adhesion layer which may be comprised of niobium, chromium, platinum, titanium, or any combination or alloys thereof.

In an embodiment of the present invention, at least one polymeric material is disposed on top of the at least one BAM layer, on top of said one or more interlayer, or on top of said one or more overcoat layer, or any combination thereof. The polymeric material includes PTFE or a material with a coefficient of friction greater or lesser than that of PTFE.

The overcoat layer of the present invention may include a composite of BAM and a second component. The second component could be a polymeric material.

In another aspect of the present invention, the overcoat layer includes an increasing concentration of the second component (e.g., the polymeric material) in a direction towards an outer surface of the substrate or a decreasing concentration of the second component (e.g., polymeric material) in a direction towards an outer surface of the substrate.

The at least one BAM layer of the present invention is disposed on the sharpened substrate via physical vapor deposition, such as magnetron sputtering, chemical vapor deposition, or any combination thereof.

The sharpened substrate may include stainless steel, metal, ceramic, composite, plastic, glass, or any combination thereof.

In a preferred aspect of the present invention, the sharpened substrate is on a blade edge of the razor blade. The blade edge could be linear, non-linear, or any combination thereof.

In a further aspect of the present invention, the BAM layer provides antimicrobial properties.

In an alternate embodiment of the present invention, a shaver apparatus includes a component having at least one layer of BAM material disposed thereon. The component may be a non-cutting element, a cutting element. The non-cutting elements contemplated by the present invention include a cartridge or handle component, such as a clip in a wet shaver or an outer or inner surface of a foil disposed in an electric dry shaver. The cutting element could be a cutter element in an electric dry shaver or a razor blade edge in a wet shaver.

A method of making a razor blade includes providing a sharpened substrate and depositing at least one layer of BAM material on an outer surface of the substrate.

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to a novel application of aluminum magnesium boride (AlMgB14, also known as BAM) based ceramic coatings to surfaces of razor components and in particular to blade edges of razor blades, as described herein. Applicants are not aware of BAM materials being used or suggested for use with razor blades. The hard and/or low friction properties of the BAM coating may provide significant benefits on razor blade edges, as these coatings may elevate blade performance and/or simplify the manufacturing process.

Baseline BAM material generally contains elemental aluminum, magnesium, and boron. The terms “BAM” or “BAM material” or “BAM layer” or “AlMgB14” or “BAM-based” or “BAM alloy” or “BAM like” will generally be used interchangeably herein and may signify the base material AlMgB14itself, a derivative of the material such as the metal boride XYB14, where X and Y are metal atoms, or the material comprised of the base AlMgB14, or XYB14, combined with a variety of single or multi-element additives, alloys, or agents which may have some impact on its properties. BAM without additive components is sometimes called base or baseline material to distinguish it from a BAM material containing second phase or solid solution additives or other elements. The additives may generally include, though would not be limited to, components such as silicon, carbon, titanium diboride (TiB2), aluminum nitride (AlN), boron nitride (BN), and/or alloying agents.

BAM (AlMgB14) is a chemical compound of aluminum, magnesium and boron, and is a ceramic alloy that is generally highly resistive to wear with a low coefficient of friction. It should be noted that BAM material may generally become harder when certain elements or compounds are added to the BAM baseline material. For instance, baseline BAM material may typically display microhardness of about 32 GPa to about 35 GPa, but additions such as titanium diboride (TiB2) may increase the microhardness to about 45 GPa producing one of the hardest known bulk materials. BAM materials have demonstrated some of the lowest coefficients of friction of currently known solids, (e.g., less than 0.05 and as low as about 0.02) as disclosed in Eaton Corporation's Final Technical Report entitledNanocoatings for High-Efficiency Industrial Hydraulic and Tooling Systems, Award No. DE-FG36-06G016054, dated Dec. 31, 2010, while the known coefficient of friction for Teflon (e.g., PTFE) widely used in commercially available razor blades as coatings for providing lubricity is generally known to be in the range of about 0.05 to about 0.10.

Consequently, a coating on a razor blade comprising BAM has the potential to exceed functionality of the current discrete hard & lubricious (e.g., low friction) coatings applied to razor blade edges in a single coating application. Since the BAM coatings will generally be both hard and low friction (e.g., slippery), they may desirably provide a single coating solution for blade edges. The need for a soft lubricious overcoat layer and/or other inter-layers such as adhesion layers or the like, may or may not be sought-after, depending on desired attributes of the blade edges and characteristics of applied BAM coating. Not having additional layers, potentially eliminates required processing steps of those layers (e.g., spray & sinter, telomer thinning), resulting in simplified manufacturing while potentially yielding a product with enhanced performance.

Furthermore, the hard nature itself of BAM coatings could result in several improvements to the blade. BAM coatings applied to standard sharpened blade substrates or geometries may outperform current hard coatings providing enhanced edge strength and wear resistance. BAM coatings may also be applied to different blade profiles which may result in further optimized blade performance.

The apparatus for processing blades with the BAM material desirably includes processes which are used currently, namely Physical Vapor Deposition (PVD) such as magnetron sputtering, however other feasible methods known in the art such as Chemical Vapor Deposition (CVD) are also contemplated as applicable processing techniques in the present invention. While stainless steel is the desired substrate of the present invention, as it is the common substrate for razor blades, blade substrates comprised of another metal or metals, ceramic, composite, plastic, glass, or any combination thereof, are also contemplated in the present invention. The BAM material coatings, by being applied to other razor cartridge components, may improve wear resistance and/or glide during shaving, particularly if disposed on clips or other hair and/or skin management components.

The term “razor blade” in the present invention desirably signifies a “substrate” comprised of stainless steel which includes a blade body and at least one flank. Desirably, a razor blade includes two flanks forming a blade edge and a blade body. The two flanks intersect at a point or tip, or what is oftentimes referred to as the ultimate tip. Each flank may have one, two or more bevels. The blade body is generally the remaining area of the razor blade beneath the flanks or bevels. As shown in a call-out section ofFIG.1, blade14includes blade body29, two bevels28for each of two flanks27which intersect at tip23forming a blade edge14a.A “substrate” signifies the substance or material acted upon in the present invention. Illustrative embodiments herein relate to a stainless steel substrate commonly used for razor blade formation.

Turning now toFIG.1, a razor10generally includes a shaving or cartridge unit16attached to a handle18with the shaving unit16having one or more blades14(e.g., 3 blades shown) each with a sharpened edge14ain accordance with the present invention. A cap12and guard13may also be included in the shaving unit16, the cap12preferably including a shaving aid composite12aaffixed thereon. The shaving unit16may be adapted for coupling and uncoupling from the razor handle18such that a new cartridge unit16may be coupled to the handle when the blades become dull or may be integral with a handle18so that the complete razor10is discarded when the blades become dull. It is noted that one or more of the blades14inFIG.1has a BAM material disposed thereon, preferably on the blade edge region.

A diagrammatic view of a blade or sharpened substrate, and in particular the blade edge region20of blade edge14aofFIG.1, is shown inFIG.2of the present invention. The blade includes a stainless steel substrate22with a sharpened edge formed in a sequence of honing operations that forms a tip portion23with a radius typically less than 500 angstroms and edge flanks27which may or may not include one or more bevels28as shown in the call-out section ofFIG.1. Deposited on the tip23and flanks27of substrate22is at least one layer of BAM material24in accordance with a preferred embodiment of the present invention. The thickness of the BAM material24may desirably range from about 300 angstroms to about 5000 angstroms and preferably range from about 500 angstroms to about 1800 angstroms, and may or may not be uniformly deposited throughout the tip and flanks. It should be noted that the BAM material may be deposited despite any variation in lengths of flanks27, angles, and aspect ratios (e.g., the ratio of the distance from the blade tip portion23to the BAM tip26and the width of BAM material coating24at the tip portion23).

The BAM coating may extend from the ultimate tip to any length down the blade edge flanks27and may or may not extend to the blade body29.

As noted above, the apparatus for processing blades of this type may desirably include magnetron sputtering while other feasible methods known in the art are also contemplated as applicable processing techniques in the present invention.

In addition, due to the presence of boric acid molecules at the outer surface24aof the BAM layer24, the BAM layer24may inherently provide anti-microbial properties ostensibly acting as a barrier to the growth of bacteria, fungus, and other organisms on the razor blades themselves which in turn may provide a clean blade to a user's skin.

In a first alternate embodiment of the present invention,FIG.3depicts blade edge region30having one or more interlayer36disposed between a BAM material coating or layer34and a stainless steel substrate32. The interlayer36may desirably include an adhesion layer which may include niobium, chromium, platinum, titanium, or alloys of the aforementioned and/or any combination thereof. The interlayer36may have a thickness of about 200 to about 400 angstroms. The interlayer36may be desirably disposed between the substrate32and the BAM material coating34to assist in adherence of the BAM coating34to the substrate32.

In a second alternate embodiment of the present invention,FIG.4depicts a blade edge region40with one or more overcoat layers49disposed on top of the BAM material layer44which is disposed on top of the stainless steel substrate42. In the present invention, the overcoat layer49(and other polymeric layers described herein) may desirably be comprised of a polymeric material that is generally highly lubricious, such as a fluoropolymer (e.g., polytetrafluoroethylene telomer, oftentimes referred to as PTFE) or may be comprised of a polymeric material or other materials that is/are generally more or less lubricious (e.g., having a coefficient of friction lesser or greater than that of the PTFE, respectively). Providing a telomer (e.g., PTFE) on the outermost surface of the blade edge endows a user's skin with lubriciousness on contact. The lubricious overcoat layer49ofFIG.4and other similar layers described herein may have a thickness of about 200 angstroms or higher.

Thus, in the present invention, even while the BAM layer44innately may generally provide both hard and lubricious properties, augmented lubricity may be desired to provide adequate or enhanced shaving attributes (e.g., glide, less tug and pull), and as such a lubricious material such as PTFE may be added to the edge region40on top of the BAM layer44. Similarly, if even with the BAM layer44, less lubricity may be desirable to provide adequate or enhanced shaving attributes, a non-lubricious material such as polypropylene may be added to the edge region40on top of the BAM layer44. Different properties on blade edges may be desirable in a blade unit.

As shown in a third alternate embodiment of the present invention inFIG.5, the embodiment ofFIG.4may include a stainless steel substrate52and one or more adhesion layer58which may be comprised of niobium, chromium, platinum, titanium, or alloys of the aforementioned and/or any combination thereof. The adhesion layer58may have a thickness of about200to about400angstroms. The adhesion layer58may be desirable to assist in adhering the polymeric layer or PTFE layer59onto the BAM material layer54, which is disposed on substrate52or for providing added hardness to the edge region50.

In a fourth alternate embodiment of the present invention shown inFIG.6, the embodiment ofFIG.4is modified depicting a blade edge region60with one or more polymeric overcoat layers69disposed on top of BAM material layer64and one or more interlayers66disposed between the BAM layer64and the substrate62. As above, the outer layer69may desirably be comprised of a polymeric material such as a PTFE telomer while interlayer66may desirably be an adhesion layer comprising niobium, chromium, platinum, titanium, or alloys of the aforementioned and/or any combination thereof. The layer66may have a thickness in the range of about 200 to about 400 angstroms. By its location, the interlayer66may desirably assist in adherence of the BAM material64to the substrate62may provide added hardness or rigidity to the edge region60. The polymeric outer layer69may desirably provide lubriciousness to the outermost surface which touches a user's skin thereby imparting a more comfortable shave.

The fifth embodiment shown inFIG.7is a modification ofFIG.6and includes blade edge region70which is substantially identical to the blade edge region60having a substrate72, a BAM layer74, an interlayer76, and a polymeric overcoat layer79with the only difference fromFIG.6being the addition of an adhesion layer78. The newly added adhesion layer78is of the type described previously in conjunction withFIG.5's adhesion layer58.

The overcoat layer of polymeric material of the present invention may be partially removed if desired to provide a thinner more uniform layer using any known methods and for example, the processes described in U.S. Pat. No. 5,985,459, entitled Method of Treating Razor Blade Cutting Edges, issued on Nov. 16, 1999, assigned to the assignee hereof, and incorporated by reference in its entirety.

Referring now toFIG.8, yet another embodiment of the present invention edge region80is depicted where at least one BAM layer84is disposed over the substrate82(as inFIG.2), but inFIG.8, at least one BAM overcoat layer85is additionally disposed on BAM layer84. The BAM overcoat layer85comprises a composite including the BAM material and at least one other element or compound, the latter material being desirably comprised of PTFE or another polymeric material. In this way, BAM overcoat layer85has an outer surface85awhich may be more or less lubricious than the surface84awould have been had the overcoat layer85not been disposed thereon.

InFIG.9, in accordance with the present invention, a modification of the embodiment ofFIG.8is depicted indicating a blade edge region90having a BAM overcoat composite layer95wherein the component materials are combined within the layer in concentration gradient. With an overcoat layer95comprising a composite of BAM material and at least one other element or compound desirably comprised of PTFE, the gradient is desirably formed such that the PTFE compound of the overcoat layer95increases in concentration in the direction from BAM layer94's outer surface towards outer surface95aof the blade edge. Accordingly, the BAM material itself decreases in concentration in the direction from BAM layer94's outer surface towards outer surface95a.Thus, if the BAM layer94is not, in and of itself, lubricious enough, increases in the concentration of PTFE towards the surface95ain the manner depicted inFIG.9(within the BAM overcoat layer95) could theoretically improve shaving attributes resulting in better glide, less tug and pull, improved overall comfort as well as less nicks and cuts.

If desirable, the concentration gradient mentioned above may be reversed, in that the BAM overcoat layer95would have increasing concentrations of the BAM material in the direction from the outer surface of the BAM layer94towards outer surface95aand the PTFE compound of the BAM overcoat layer95decreases in concentration in the direction from BAM layer94's outer surface towards outer surface95a.

It should be noted that the presence of a concentration gradient as described inFIGS.8and9in the present invention is contemplated for BAM layers as well, with or without the presence of a BAM overcoat layer.

With the embodiments described as having an overcoat layer (e.g., layers58and78inFIGS.5and7), the present invention contemplates still further that a BAM overcoat layer95may be disposed on top of any overcoat layer (e.g., layers58and78inFIGS.5and7) rather than directly disposed over the BAM layer94.

Moreover, the BAM overcoat layer95may be a composite comprised of the BAM material and several other elements or compounds, in lieu of or in addition to the PTFE mentioned herein offering the benefits of lubriciousness for instance.

It is further contemplated in the present invention that the BAM material layer94itself is formed having a concentration gradient.

The embodiments described herein have generally described linear blades with generally planar or straight edge regions and bevels. However, the present invention further contemplates the BAM material104disposed on upper surfaces107of non-linear (shown as circular) blade unit edges107aof substrate (not shown) in blade edge region100as depicted inFIG.10. The BAM material may be deposited using any of the processes described herein. It follows that any of the alternate embodiments shown inFIGS.2-9in conjunction with linear blades, can be similarly extended to the embodiment inFIG.10. For instance, in conjunction withFIGS.3and6, the non-linear blade edge ofFIG.10may first be coated with an interlayer (not shown inFIG.10) on top of which a BAM material104layer is deposited.

The non-linear blade edges of the present invention may be of the types described in U.S. Pat. No. 4,807,360 entitled Shaving Device, issued on Feb. 28, 1989, and/or U.S. Pat. No. 4,875,228 entitled Shaving Device, issued on Oct. 24, 1989, both assigned to the assignee hereof, and incorporated by reference in their entireties.

The present invention further contemplates the BAM material in addition to being deposited on blade edges, being deposited on any other razor components, such as those components designated inFIG.1. The coatings of BAM material, if applied to other razor cartridge components, may theoretically improve wear resistance and/or glide during shaving, particularly if disposed on clips or other hair and/or skin management components.

Referring now toFIG.11, an example of a BAM material114disposed on razor cartridge components, the two blade retaining clips11ofFIG.1are shown in accordance with another embodiment of the present invention. The shaving benefits of glide and comfort along the shave path may be augmented by adding the BAM material (e.g., a hard and lubricious material) on the upper surface11aof the clips11which are generally disposed on the left and right sides of the cartridge. The BAM material114may be deposited by means of magnetron sputtering, as described above, or other feasible methods.

Referring toFIG.12, an example of BAM material124disposed on electric dry shaver components, such as on outer and/or inner surfaces of a foil120component or dry shaver cutter elements122is shown in accordance with another embodiment of the present invention. An electric or dry razor generally consists of a set of oscillating or rotating blades or cutters122, which are held behind a perforated metal foil120which prevents them from coming into contact with the skin and behaves much like the second blade in a pair of scissors. When the razor is held against the skin, the whiskers poke through the holes121in the foil120and are sliced by the moving cutters122. Typically, there is no lubricant applied in dry shaving. The addition of a BAM coating, for instance, on the outer surface of the foil, may improve skin glide. Further, an advantage of having a BAM coating on the inner surface of a foil (not shown) may generally include the reduced friction between the foil and cutters, which may provide a cooler shave, increased battery life and/or increased foil longevity. A BAM coating124disposed on the outer surface of the cutter elements122themselves as shown inFIG.12, may also desirably provide enhanced hardness of the cutters and reduced friction.

Thus, as described above, with BAM material being used on blade edges, there is a potential to provide a single coating (delivering both hard and lubricious benefits) solution to deliver optimized blade performance and simplified manufacturing. Further, as also described above, the BAM material may be applied to other razor components such as those in the cartridge or on the handle and/or dry shaver components such as foils and cutter elements and in turn provide improved shaving benefits such as wear resistance and lubricity.