Formation of thin uniform coatings on blade edges using isostatic press

The invention discloses isostatic-pressing (IP) applied to polymer (e.g., PTFE) coated razor blade edges to produce thin, dense, and uniform blade edges which in turn exhibit low initial cutting forces correlating with a more comfortable shaves. The isostatic press utilized may be a hot isostatic press (HIP) or cold isostatic press (CIP) or any other isostatic press process. The HIP conditions may include an environment of elevated temperatures and pressures in an inert atmosphere. The HIP conditions may be applied to non-sintered coatings or sintered coatings or before or after a Flutec® process is applied to coatings. CIP conditions may include room temperature and elevated pressure. The polymeric material may be a fluoropolymer or a non-fluoropolymer material or any composite thereof. It may be deposited initially by any method, including but not limited to, dipping, spin coating, sputtering, or thermal Chemical Vapor Deposition (CVD).

FIELD OF THE INVENTION

This invention relates to razor blades, and more particularly to coatings on razor blade cutting edges and manufacture thereof.

BACKGROUND OF THE INVENTION

It is generally known in the prior art that a wet razor assembled with fluoropolymer coated blades outperforms a razor assembled without fluoropolymer-coated blades. One of the most common fluoropolymers utilized for coating razor blades is polytetrafluoroethylene or PTFE (or a form of Teflon®). The addition of PTFE (e.g., telomer) coating to the blade cutting edge dramatically reduces the cutting forces for beard hairs or other types of hair fibers. A reduced cutting force is desirable as it significantly improves shaving attributes including safety, closeness and comfort. Such known PTFE-coated blade edges are described in U.S. Pat. No. 3,071,856.

There are many types of coating processes that could be utilized to produce polymer coated (e.g., PTFE) coated blade edges. Some processes involve aqueous dispersion of the PTFE and some involve organic dispersion of the PTFE. Aqueous dispersion processes may include spraying, spin coating and dipping. PTFE may also be deposited on blade edges using vacuum based processes such as sputtering or thermal Chemical Vapor Deposition (CVD). However, when quality, cost and environmental issues are considered, the spraying of an aqueous PTFE dispersion is typically desired. PTFE dispersion in an organic solvent is also a known process in the art. This type of dispersion may include for example, Dupont's Vydax 100 in isopropanol as described in U.S. Pat. No. 5,477,756.

Regardless of whether an aqueous or organic based dispersion is utilized, if a spraying process is utilized along with a subsequent sintering process, a non-uniform surface morphology, on a microscopic scale, is produced on blade edges and in the area proximal to the ultimate blade tips as shown inFIG. 1. This may be caused by the particle size dispersion of PTFE particles and by the wetting and spreading dynamics of dispersion. Typically, the average thickness of PTFE coating produced by a spraying process is about 0.2 μm to about 0.5 μm.

It should be noted that the thinner the PTFE coating becomes on blade edges, the lower the cutting force (assuming the coating is uniform). While this is generally desirable as mentioned above, too thin PTFE coatings on blade edges can give rise to poor coverage and low wear resistance due to intrinsic properties of the PTFE material. Alternatively, a too thick PTFE coating may produce very high initial cutting forces, which generally may lead to more drag, pull, and tug, eventually losing cutting efficiency and subsequently shaving comfort. Thus, there is a technical challenge to balance the attributes of the polymer material with obtaining the thinnest coating possible to provide improved shaving attributes.

This fuels the desire in the art to form a thin, dense and uniform PTFE coating with extremely low coefficient of friction onto the blade edge.

Previous efforts made towards this objective, such as selection of different PTFE dispersions, modification of the surfactant used in the dispersion and/or optimization of spray-sintering conditions have had moderate effectiveness.

Some known solutions for thinning the PTFE on the blade edges include (1) mechanical abrasion, polishing, wearing, or pushing back; (2) a high energy beam (electron, gamma ray or X-ray, synchrotron) or plasma etching; and (3) application of Flutec® technology or Perfluoper-hydrophenanthrene (PP11) oligomers.

The disadvantage of the first mechanical abrasion solution is that it is difficult to control, may produce non-uniform thinning and may also cause edge damage. The disadvantage of applying high energy beams to thin the PTFE is that it may change the cross linking and molecular weight of PTFE thereby increasing friction and hence, cutting force.

One relatively successful approach has been the application of Flutec® technology as described in U.S. Pat. No. 5,985,459 which is capable of reducing the thickness (e.g., or thinning) a relatively thick PTFE coating produced by a spray and sintering process. This prior art process, as shown inFIG. 1depicts a flow10where blade12which has sprayed PTFE particles11coated on and around its tip13is sintered as shown at step14with Argon at about 1 atmospheric pressure (1 atm) and at a temperature of about 330 degrees Celsius (° C.) to about 370° C. to produce a sintered PTFE coating16. Typically, the average thickness of PTFE coating produced by a spraying process is about 0.2 μm to about 0.5 μm.

The Flutec® technology as shown at step17is subsequently placed on coating16to produce a thinned PTFE coating18. This typically includes soaking the PTFE coated blades16in solvents under elevated temperatures of about 270° C. to about 370° C. and at a pressure of about 3 atm to about 6 atm. In general, the solvents employed in the Flutec® process include solvents such as perfluoroalkanes, perfluorocycloalkanes, or perfluoropolyethers.

With the Flutec® approach, a more uniform PTFE coating18with about 10 nm to about 20 nm in thickness may be achieved consequently resulting in a reduction of the first cutting force of blade edges on wool-felt-fibers of nearly 40% compared to many approaches utilized prior to the knowledge of the Flutec® treatment. However, a major drawback to the Flutec® process is that even though most of the solvents used are capable of being recycled, some needs to be disposed of as waste.

Another disadvantage of the Flutec® technology is that the chemical solvent used in the Flutec® process typically removes most of the PTFE materials from the sintered coating18which, as mentioned above, provide the improved shaving attributes.

Another disadvantage of the Flutec® technology is that generally the resultant Flutec® coatings still exhibit porosity since coating molecules are not densely packed. Because of this, a coating with a desirably high molecular weight is difficult to achieve.

Thus, there is a need for an alternative apparatus and method to produce thin, uniform and dense coatings on blade edges.

SUMMARY OF THE INVENTION

This invention provides a method for forming a razor blade including isostatically pressing (IP) at least one blade edge coated with at least one polymeric material.

The polymeric material of the present invention includes a fluoropolymer such as PTFE. The isostatic press may be a hot isostatic press (HIP) or a cold isostatic press (CIP). The resulting isostatically-pressed coating ranges in thickness from about 10 nm to about 100 nm, has a substantially uniform surface morphology, and has substantially zero porosity.

In certain embodiments, the isostatic press conditions include a temperature in the range of about 300° C. to about 380° C., a pressure range of about 10 MPa to about 550 MPa, an inert atmosphere of argon or nitrogen where the isostatic press conditions may be applied for a time ranging from about 10 minutes to about 10 hours.

The isostatic press conditions may be applied to a polymer coating on the blade edge after the polymer coating has been sintered or undergone Flutec® application.

In one aspect of the present invention, the polymeric material is comprised of a non-fluoropolymer.

In yet another aspect of the invention, the razor blade substrate may include blades which are steel with or without a top layer coating of Chromium (Cr), Diamond-like Carbon (DLC), Amorphous Diamond, or Chromium/Platinum (Cr/Pt).

In still yet another aspect of the invention, the blade edge of the present invention may be initially coated with the polymer material by dipping, spin coating, sputtering, or thermal Chemical Vapor Deposition (CVD).

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to razor blade cutting edges which are formed such that they exhibit an improvement in shaving attributes in the first few shaves. One principal aspect of the invention is directed towards forming a thin, dense and uniform coating on the blade edge which has a low cutting force and low friction. The term “thin” refers to the thickness of the coating of the present invention. Generally, the thinner the coating becomes on blade edges, the lower the cutting force and the better the shaving attributes. The term “dense” as used herein signifies the lack or substantial elimination of porosity exhibited in the coating of the present invention. Denseness is desirable as it provides for lower friction and cutting forces, more consistent shaves, in addition lower wear rates (e.g., longer blade life). The term “uniform” as used herein refers to the surface morphology (e.g., smoothness) exhibited in the coating of the present invention. Similarly, the more uniform the surface of the coating is the more comfortable the shave will be and the lower the wear rate, among other things. As mentioned above, a commonly utilized material for blade edge coating is a type of fluoropolymer, namely PTFE. As such, PTFE will be referenced throughout the description of the instant invention but not to the exclusion of other materials (mentioned below) which may be substituted substantially equivalently.

Razor blade edges produced according to the present invention, as will be described below, exhibit lower initial cutting forces which correlate with more comfortable first few shaves, than those produced by conventional spraying and sintering technologies.

The invention discloses a novel application of a known process or technology called isostatic pressing which may include hot isostatic pressing (HIP), cold isostatic pressing (CIP), other related CIP processes or other isostatic processes. Generally, isostatic presses are known to be used for compressing materials such as ceramics, metal alloys and other inorganic materials. Some examples of the uses of HIP process include ceramic turbine blades, nickel based super-alloy turbines, aluminum casting and materials that need low porosity. While isostatic pressing processes represent a relatively mature technology, they have generally not been utilized in the polymer industry.

As shown inFIG. 2, the HIP process apparatus20typically subjects components to both elevated temperature in a heating chamber23and elevated isostatic gas pressure in a high pressure containment vessel24. In the instant invention, the components placed in the apparatus20are razor blades, inserted for instance in the form of blade spindles22. A vacuum25pumps air into the vessel24. A pressurizing gas most commonly used in a HIP process via compressor27is Argon (Ar) which is an inert gas. Other gasses may be used such as nitrogen. Such an inert gas is used to reduce damage to the blades and the polymer material. The HIP chamber20is heated, causing the pressure inside the pressure vessel24to increase and the gas, pressure and temperature are managed by a control unit28. Generally, isostatic processes such as HIP may be applied for a time ranging from about 10 minutes to about 10 hours, desirably about 20 to 30 minutes.

In all types of isostatic processes, pressure is applied to the component from all directions; hence the term “isostatic.”

Though not shown inFIG. 2, the CIP process is fairly similar to the HIP process except that it functions at room temperature and may involve a liquid medium (often an oil-water mixture) as a pressure mechanism, pumped in and pressurized on all sides to produce a uniform product and may in many instances require additional processing (e.g., such as sintering) to provide an adequate finished product. Generally, CIP involves applying high isostatic pressure over about 98 MPa (1000 kgf/cm2) to about 550 MPa. CIP is a very effective powder-compacting process. Two well-known CIP methods include the wet-bag process in which the powder substance enclosed in a rubber bag is directly submerged into the high-pressure medium, and the dry-bag process in which the pressing work is accomplished through rubber molds built into the pressure vessel.

For purposes of the present invention, it is contemplated that any of the known isostatic pressing processes may be used substantially interchangeably to generate the desired product results with plausibly some modifications either in temperature, pressure or added processing. Hence, while a hot isostatic pressing embodiment of the present invention is described in more detail below, the notion to use any of the other types of isostatic pressing (either in addition to or in its place) is contemplated in the present invention.

In a desirable embodiment of the present invention, hot-isostatic-pressing is used on blade edges or polymer coated (e.g. PTFE-coated) blade edges to produce thin, dense, and uniform blade edges. One major advantage of utilizing an isostatic pressing process such as the HIP process over the prior art Flutec® process is that the isostatic processes (e.g. HIP) typically do not involve the use of any organic solvents, thereby providing an environmentally benign and simple solution.

The hot isostatic press (HIP) when applied to PTFE coating on blade edges in the present invention forces the PTFE coating on the blade edges to sinter and creep (similar to melting) as will be described below. Sintering will heat and form a coherent mass of the PTFE particles. Creeping will gradually and permanently deform the PTFE particle coating upon continued application of heat or pressure. Thus, by causing the material to sinter and creep (similar to melting), the HIP process is capable of forming a dense, thin uniform PTFE coating on the blade edge.

In one aspect, the novel application of the hot-isostatic-pressing (HIP) process in the present invention for the treatment of PTFE coated blade edges (e.g., traditionally spray or spray-sintered) may produce extremely thin, dense and uniform PTFE coatings. As mentioned above, it has been known that both PTFE coating thickness and its morphology on the blade edge are very critical and important in terms of lowering the cutting force and obtaining a better shaving experience.

Thus, the HIP process applied to blade edges provides a new application for HIP conditions that may effectively manipulate the thickness of a polymer coating as described below. In one embodiment of the present invention ofFIG. 3, a hot-isostatic-press is used on coated blade edges to produce thin, dense, and uniformly coated blade edges.

Referring now toFIG. 3, at least one blade32which includes at least one polymer coating such as PTFE particles34(e.g., previously sprayed) on and around blade tip33is, at step35, subjected to HIP conditions as described in conjunction withFIG. 2to provide a thin uniform PTFE coating38on blade32in accordance with an embodiment of the present invention.

The HIP conditions at step35in the present invention may include a temperature in the range of about 300° C. to about 380° C. or a temperature near the PTFE melting temperature which is about 327° C. A desirable temperature in the present invention may be from about 330° C. to about 370° C. In addition, in the present invention the HIP conditions at step35may include a pressure range of about 100 MPa to about 550 MPa. Usually HIP is run at about 100 MPa to about 350 MPa and desirably at about 220 MPa. As mentioned above, the HIP conditions at step35in the present invention may necessarily include an inert atmosphere, desirably in argon or nitrogen.

By having a rather high HIP temperature, the PTFE coating is softened as mentioned above, thereby enhancing the deformity or “creep” or flow of the PTFE material (e.g., similar to melting) over the blade edge surface. As the PTFE material flows, it creeps into the apertures34aofFIG. 3within the surface of the blade edge. The removal of most of the apertures provides for a dense coating with substantially zero porosity. In addition to this creeping mechanistic during the HIP process, the high HIP pressure simultaneously pushes the existing thick PTFE coating in the vicinity of blade tips away from the tip so that a very thin, dense, and uniform coating is formed on the blade tip edge33as shown inFIG. 3at coating38. The thickness of resulting PTFE coating38ofFIG. 3is in the range of about 10 nm to about 100 nm and desirably about 20 nm. The thickness38aof coating38is substantially uniform throughout all areas of the coating with the potential for some slightly non-significant or slightly thicker areas (e.g., at the blade tip). The surface morphology of coating38is smooth having virtually no agglomerations of PTFE particles (e.g., areas of non-uniformity in thickness or protruding PTFE particles) thereby providing optimal friction and cutting force. In some instances, the surface area32bcovered by coating38(e.g., after HIP) may be greater than the surface area31covered by coating34. The surface area or length37is desirably greater than 150 μm as this is approximately the area of the razor blade that would touch a user's skin. Because HIP conditions are generally provided with the capacity for good quality control, the desired coating dimension of 150 μm is generally easily attainable.

The characteristics of the coating38of the present invention are much improved over coating34. One way to recognize this relies on evaluations of the interference color of PTFE coating38. For instance, as shown in the photographs ofFIG. 3aandFIG. 3b, the use of an optical microscope with polarized light is one way to evaluate the characteristics (e.g., uniformity, surface morphology, denseness etc.) of PTFE coated blade edges. InFIG. 3a, a non-sintered PTFE coating (e.g., coating34ofFIG. 3) is shown taken before the HIP process is applied where 2.50 wt % of Dupont's LW1200 PTFE dispersion was utilized with a molecular weight average of about 45,000 Dalton.FIG. 3acorresponds to a photograph of bevel area32bor one side of the blade edge ofFIG. 3, the blade edge32chaving a total length of about 250 um. Tip33is denoted at the bottoms of the photographs inFIGS. 3aand3b.

After the HIP process is applied (e.g., at step35ofFIG. 3) at or about 370° C. and at or about 250 MPa, the resultant coating38produced conforms over the surface of the blade edge in that it effectively “hugs” the contours of the surface and creeps the polymer into the apertures34aofFIG. 3within the surface of the blade edge. It also may smooth out groups of PTFE particle clusters34b. These spots34bindicate areas of non-uniformity in the surface morphology of the coated blade edge in that they may add thickness in those areas; such a thickness is not desirable (e.g., at the tip33of the blade) as it may affect the friction and cutting force. Coating38is depicted in the photograph ofFIG. 3b. The naked eye may easily note the differences in the coating surface morphology between the “before HIP” photograph (shown inFIG. 3a) and the “after HIP” photograph (shown inFIG. 3b). One visible difference includes the substantial elimination inFIG. 3b's photograph of pores34aand PTFE particle agglomerations34b.

In general, coverage of PTFE coating on the blade edge substrate and the surface (or biological) properties of the coating will be improved after HIP processes. In particular, one improved characteristic is the thickness of the PTFE coating around the ultimate tips of the blade edges may be substantially thinned and uniform, a desirable result significantly lowering the cutting force of the blades (e.g., wool-felt fiber or hair fiber cutting force is significantly reduced). For example, the 1stwool-felt-cut force (or cutting force) may have a percentage force reduction after HIP processing from about 15% to about 65% or the 1stwool-felt-cut force (or cutting force) be reduced in the range of about 1.10 lbs to about 1.70 lbs after HIP processing.

This consequence of the HIP process (e.g., lowering of the first cutting force of the blade edge substantially compared with traditional sintering processes) provides blade edges with lower first cutting force leading to more comfortable and closer shaves. It has been shown that improved shaving attributes such as closeness and comfort have been achieved with HIP-treated PTFE coated blades for a wet shaving system.

Since the novel HIP technology applied to blade edges provides a non-chemical technique for thinning the PTFE coating on blade edges, it is also advantageous over known chemical processes (e.g., Flutec® technology) since there is no loss of PTFE material. It follows that, under optimized conditions, this novel technique as described herein may be an alternative approach to known thinning processes, (e.g., ofFIG. 1depicting spray sintering and Flutec® technology) and as such, may be used in lieu of these processes entirely.

FIGS. 3,3aand3babove describe the HIP process applied directly to treat polymer coated blades that have not undergone any other treatment (e.g., sintering) to thin the coated polymer and achieve low cutting force blade edges, a simplification of the polymer coating process as a whole.

Referring now toFIG. 4, in another embodiment of the present invention the HIP process may be applied after PTFE coated blade edges are treated by sintering. As illustrated inFIG. 4, blade42which includes a coating with PTFE particles44(e.g., sprayed) on and around blade tip43is subjected to sintering at step45. The sintering step includes subjecting blade42to at or about 1 atm and from about 330° C. to about 370° C. After the sintering step, there may be a significant reduction in apertures44afound within coating46. This provides for a coating46with some improved density. Groups of PTFE particles44bdepict agglomerations and indicate areas of non-uniformity in coating44and may also, after sintering, be reduced though may remain in coating46as shown inFIG. 4at spots46a. As shown inFIG. 4, the PTFE particles46after sintering are smoother than original PTFE particles44. The thickness of PTFE particles46may be about 0.2 μm to about 1 μm. Subjecting blade42with particles46to HIP conditions as depicted at step47provides a thinner uniform PTFE coating48on blade42in accordance with another embodiment of the present invention. The thickness of PTFE particles48is about 10 nm to about 100 nm, or desirably about 20 nm. The HIP conditions at step47inFIG. 4are similar to the HIP conditions described above in conjunction withFIG. 3.

Again, by having a rather high HIP temperature, the PTFE coating46is softened thereby enhancing the deformity or “creep” or flow of the PTFE material over the blade edge surface. As the PTFE material flows, it further creeps into any remaining apertures or pores44aofFIG. 4within the surface of the blade edge. The removal of the apertures44aprovides for a desirable dense coating with substantially zero porosity which provides consistent shaves, lower friction, and improved wear rates. Groups of PTFE particles44bdepict agglomerations and indicate areas of non-uniformity and are also substantially smoothed out and reduced further during the HIP step47. Spots46ainFIG. 4within coating46also depict remaining agglomerations of PTFE particles. These spots46aindicate areas of non-uniformity in the surface morphology of the coated blade edge in that by protruding out they may add thickness in those areas and this generally is not desirable as it may negatively affect the friction and cutting force. These spots46amay be substantially removed in resultant coating48. Thus, the porosity in resultant coating48is substantially non-existent with few, if any, apertures44aand other agglomerations44bwith a resultant surface morphology being substantially uniform, smooth and few, if any, PTFE particles46a.

In addition to this creeping mechanistic during the HIP process, the elevated HIP pressure simultaneously pushes the existing thick PTFE coating in the vicinity of blade tips back and away from the tips so that a very thin and uniform PTFE coating48is formed on the blade tip edge43as shown inFIG. 4. The thickness of resulting PTFE coating48ofFIG. 4as mentioned above with respect toFIG. 3is about 10 nm to about 100 nm, and desirably about 20 nm.

Referring now toFIGS. 4a,4b, and4c, the improvements of the coating characteristics over the three stages described in conjunction withFIG. 4are depicted by optical microscope photographs. These photographs as mentioned above assist in showing the interference color of PTFE coating by using polarized light as a way to evaluate the characteristics (e.g., uniformity, surface morphology, and density) of PTFE coated blade edges. Each photograph inFIGS. 4a,4b, and4crespectively corresponds to each bevel area42bofFIG. 4, where the blade edge may have a total length42cof about 250 um. Tip43is denoted at being at the bottoms of the photographs inFIGS. 4a,4b, and4crespectively. These photographs were taken with a 2.50 wt % PTFE (Dupont Te-3667N dispersion) coated blade edge sample at different stages. The molecular weight average is about 110,000 Dalton. The molecular weight range of the present invention coating ranges from about 3000 to 1 million Dalton, and is desirably in the range of about 40,000 Dalton to about 200,000 Dalton.

InFIG. 4a, coating44ofFIG. 4is shown applied to blade42before the sintering step45in optical microscope photograph A. A traditionally sintered PTFE coating (e.g., coating46ofFIG. 4) is shown inFIG. 4btaken at 343° C. in Argon and at 1 atm before the HIP process is applied. After the HIP process is applied (e.g., at step47ofFIG. 4) at or about 343° C. in Argon and at about 2040 atms, the resultant coating48produced conforms over the surface of the blade edge in that it effectively “hugs” the contours of the surface and creeps the polymer into the apertures44aofFIG. 4within the surface of the blade edge. Resultant coating48is depicted in the photograph ofFIG. 4c.

The naked eye may easily note the differences in the coating surface morphology amongst the “before sintering” photograph (shown inFIG. 4a), the “after sintering” photograph (shown inFIG. 4b) and the “after HIP” photograph (shown inFIG. 4c). One visible difference includes the elimination in photographs ofFIGS. 4band4cof the many agglomerations of PTFE particles46aand the apertures (or pores)44a. Particles46aindicate areas of non-uniformity in the surface morphology of the coated blade edge in that by jutting out they may add thickness in those areas.

Referring now toFIGS. 5a,5b, and5c, an illustration of non-uniform and uniform thickness profiles is shown and are all depicted in graph form inFIG. 6. Coating52is a non-uniform PTFE coating on a blade edge of the blade depicted inFIG. 5awhere coating52is visually thicker on blade edges or sides depicted at52athan at the blade tip shown at52b. Coating54is a non-uniform PTFE coating on a blade edge of the blade depicted inFIG. 5bwhere coating54is visually thicker at the tip of the blade shown at54bthan on the sides54aof the blade. In accordance with the present invention, coating56is shown to be of substantially uniform thickness at blade sides56aand tip of the blade56bof the blade depicted inFIG. 5c. In some instances, the thickness at the tip of the blade56bmay be slightly greater (not shown) than the thickness at the blades sides56a. The range of dimensions for52a,52band54a,54bare about 0.2 um to about 1 um and are reduced at56bfrom about 20 nm to about 100 nm.

Coating thicknesses52a,52b,54a,54b,56a, and56bof blades depicted inFIGS. 5a,5b, and5c, vis-à-vis the distance from the blade tip, are also depicted in graph form inFIG. 6where the x-axis represents the coating thickness values and the y-axis represents the distance from the blade tip values. As shown inFIG. 6, the blade ofFIG. 5cwith coating56has a uniform thickness (e.g., straight line66on the graph) regardless of the distance from the blade tip, whereas the blade ofFIG. 5bwith coating thicknesses54aand54bis depicted by a curve line64showing that the coating thickness is thickest at the tip but decreases the further it is away from the blade tip and whereas the blade ofFIG. 5awith coating thicknesses52aand52bis depicted by a curve line62showing the coating as being thickest midway down the bevel edge of the blade and relatively thin at the blade tip.

It should be noted that HIP is less sensitive to what the pre-formed PTFE coating embodies in terms of thickness, uniformity, molecular weight, particle size, etc., and so it follows that, any method of initial PTFE coating may be utilized in accordance with the present invention, including, but not limited to, dipping, spin coating, sputtering, and thermal Chemical Vapor Deposition (CVD). Thus, no matter how non-uniform or poor an initially formed polymer coating is, the HIP process through the redistribution of PTFE material within the coating may produce a smoother, denser, more uniform coating with fuller coverage. Thus, advantageously it is contemplated that a simple dipping process could replace a spraying process for producing the initial polymer (e.g., PTFE) coating despite the former process having a less uniform outcome than the latter process.

It is further contemplated (not shown) that the present invention may include the prior art Flutec® technology ofFIG. 1with the isostatic processes (e.g., HIP process) herein described applied to the blade coating either before or after the Flutec® process.

Additionally, different dispersions or other forms of raw materials from various vendors may be readily used to achieve thin and uniform coatings.

Thus, the benefits obtained from the isostatic press approach on PTFE coated blades are achieved regardless of the method utilized for the initial PTFE coating on a blade edge and as such, is not limited to a particular coating type (e.g., a spraying process).

This indicates that the IP technology may generally be more robust in terms of blade edge quality and provide potentially beneficial cost savings.

The IP (HIP or CIP)-produced improved morphological features on the coating will minimize cutting force variations of the blade edge and better protect the blade from being damaged. Further, the IP processes will improve overall product quality and help consumers to achieve a smooth and consistent shave experience.

The present invention contemplates that the isostatic processes such as the HIP or CIP, or other related isostatic processes may also be applicable to being used with other fluoropolymers in addition to PTFE, including but not limited to PFA (perfluoroalkoxy polymer resin), FEP (fluorinated ethylene-propylene), ETFE (polyethylenetetrafluoroethylene), PVF (polyvinylfluoride), PVDF (polyvinyllidene fluoride), and ECTFE (polyethylenechlorotrifluoroethylene).

The present invention contemplates that the isostatic processes such as the HIP or CIP, or other related isostatic processes may also be applicable to being used with fluoropolymer (e.g., PTFE) composites, including, but not limited to PTFE/nanodiamond, PTFE/silica, PTFE/alumina, PTFE/silicone, PTFE/PEEK (polyetheretherketone), and PTFE/PFA.

Furthermore, the HIP process of the present invention is not necessarily constrained to being applied to PTFE or PTFE type materials and may also be applicable to other non-fluoropolymer (e.g., non-PTFE) coating materials, including, for instance, but not limited to, polyvinylpyrorridone (PVP), polyethylene, polypropylene, ultrahigh molecular weight polyethylene, polymethyl methacrylate, parylene and/or others.

Additionally, the razor blade substrate may be comprised of steel with or without top layer coatings such as Chromium (Cr), Diamond-like Carbon (DLC), Amorphous Diamond, Chromium/Platinum (Cr/Pt) or other suitable materials or combination of materials. It has been shown that the blade substrate being comprised of these materials (e.g., Cr or DLC) improves adhesion of the polymer coating material on the blade edge after HIP conditions have been applied.

In another embodiment of the present invention it is contemplated that the HIP conditions may be used in conjunction with a dry shaver in addition to a wet shaver where the cutter blades of the dry shaver are similarly subjected to HIP conditions as described above.

It is further contemplated in yet another embodiment of the present invention that the HIP conditions described above may be used in conjunction with blades that are implemented in medical or surgical instruments, such as surgical blades, scalpels, knives, forceps, scissors, shears, or the like or other non-surgical blades or cutting instruments.