Method of treating razor blade edge

Abstract

A method of manufacturing a razor blade edge, the method comprising: applying a single coating of a polymeric material to the razor blade edge to form a coated edge; performing a single heating of the coated blade to adhere the polymeric material to the razor blade blade, wherein the single heating of the coated blade comprises a first heating section and a second heating section; and optionally, treating the coated blade with a solvent or mechanical method to partially remove the coating. The present disclosure also provides a razor blade edge produced according to the disclosed method.

Description

Technical Field

[0001] The present disclosure relates generally to methods of making treated razor blades, and more particularly to improved sintering methods. Background Art

[0002] It is generally known that razor blades can be coated with polyfluorocarbons to prevent discomfort and pain during shaving. Current methods for coating razor blades include applying a polyfluorocarbon dispersion and then sintering the polyfluorocarbon polymer to the blade. Methods for coating razor blades are described in U.S. Patent Nos. 9,393,588 and 10,118,304.

[0003] During the sintering process, the duration at the target temperature is critical because it drives the bonding of the polymer and the hard outer layer of the blade. Most current methods only keep the blade at the target temperature for a short period of time. While some methods do increase the time period at the target temperature, these processes are labor-intensive and equipment-intensive. For example, one method of increasing the time at temperature includes repeating the steps of applying the polyfluorocarbon and sintering.

[0004] Therefore, there is a need for an improved, efficient method to increase the time at temperature without increasing the processing time of the razor blade. SUMMARY OF THE INVENTION

[0006] According to the present disclosure, a method of manufacturing a razor blade edge is provided, the method comprising: applying a single coating of a polymer material to the razor blade edge to form a coated edge; performing a single heating of the coated edge to adhere the polymer material to the razor blade edge, wherein the single heating of the coated edge comprises a first heating section and a second heating section; and optionally, treating the coated edge with a solvent or mechanical method to partially remove the coating.

[0007] BRIEF DESCRIPTION OF THE DRAWINGS

[0008] While the specification concludes with claims particularly pointing out and distinctly stating the subject matter regarded as forming the present invention, it is believed that the present invention will be better understood from the following description taken in conjunction with the accompanying drawings in which like reference numerals are used to designate substantially identical elements, and wherein:

[0009] Figure 1A is a schematic flow chart of a method of manufacturing a razor blade edge according to the present disclosure.

[0010] Figure 1B It is executing Figure 1A A graphic depiction of the blade edge following each step of the flow chart.

[0011] Figure 2Ais a schematic flow chart of another method of manufacturing a razor blade edge according to the present disclosure.

[0012] Figure 2B It is executing Figure 2A A graphic depiction of the blade edge following each step of the flow chart.

[0013] Figure 3A is a schematic flow chart of another method of manufacturing a razor blade edge according to the present disclosure.

[0014] Figure 3B It is executing Figure 3A A graphic depiction of the blade edge following each step of the flow chart.

[0015] Figure 4 is a schematic diagram of a chamber showing a razor blade that can be coated via deposition techniques in accordance with the present disclosure.

[0016] Figure 5 is a perspective view of a razor cartridge including a razor blade edge having a uniform coating in accordance with the present disclosure.

[0017] Figure 6 is Figure 2A and Figure 3A Graph of the temperature of the razor blade during the sintering process.

[0018] Fig. 7A and Figure 7B is a graph of the average delta cutting force for various insert examples. DETAILED DESCRIPTION OF THE INVENTION

[0020] Definition of terms

[0021] As used herein, the term "razor blade edge" includes the cutting point or final blade end and one or more facets of the razor blade. The entire blade edge can be coated in the manner described herein; however; an encapsulated coating of the type described herein is not considered necessary for the present disclosure. Razor blades according to the present disclosure include all types known in the art. For example, stainless steel blades are commonly used. Many other commercial razor blades also include chromium or a chromium layer / platinum layer between the steel blade and the polymer. Other layers are also feasible and are known in the art. Prior to polymer coating, a chromium layer is typically sputtered onto the blade surface. In addition, a similar method can be used to coat the blade with other materials prior to external polymer coating, such as, but not limited to, a diamond-like carbon (DLC) material coating as described in U.S. Patent Nos. 5,142,785 and 5,232,568.

[0022] The term "composition of a razor blade edge" generally refers to the base material, the sharp profile of the edge, and any coatings applied to the edge.

[0023] As used herein, a "uniform" coating or "uniformity" of a coating means that the coating provides substantially complete coverage while having a generally consistent average depth and / or a substantially uniform profile throughout.

[0024] As used herein, "average molecular weight" generally refers to the number average molecular weight of the polymer used to produce the polymer coating. The molecular weight is equal to the total weight of all polymer molecules in a representative sample divided by the total number of polymer molecules in the representative sample. As used herein, the term "molecular weight distribution" refers to the molecular weight distribution that produces the number average molecular weight of a representative sample. As can be appreciated by those skilled in the art, the average molecular weight between two materials can be the same, but their respective molecular weight distributions can be quite different.

[0025] The removed portions of the polymer coating may generally be referred to as the "non-adherent" soluble polymer molecules of the coating.

[0026] Method for manufacturing razor blade edge

[0027] Figure 1A and Figure 1B 1 is a flow chart of an exemplary method 10 for manufacturing a razor blade edge, the method involving two two-stage heating steps. The method 10 may begin by introducing 12 a razor blade edge 72. Figure 1B As shown, a razor blade edge 72 has an edge 12a, which may optionally include one or more prior coatings deposited thereon. The blade 12a shown may include a substrate 74, an interlayer 76, a hard coating 78, and a protective layer 80. The razor blade edge 72 may be formed by, for example, a stainless steel substrate 74, a niobium interlayer 76, a diamond or DLC hard coating 78, and a chromium-containing protective layer 80, and any of these layers may include (i) diamond, amorphous diamond, or DLC; or (ii) chromium, platinum, boron, chromium diboride, titanium, titanium diboride, vanadium, aluminum, silicon, tin, tantalum, zirconium, niobium, magnesium, manganese, iron, cobalt, copper, silver, zinc, hafnium, tungsten, molybdenum, or nickel and their oxides, nitrides, borides, and oxynitrides. Other types and quantities of layers are also contemplated in the present disclosure.

[0028] At step 14, a polymer material may be applied to the razor blade edge 72 to produce a coated edge 14a including a polymer coating 90. The polymer material may be applied as a dispersion of the polymer material in a dispersion medium. The polymer may be a polyfluorocarbon. In some examples, the polymer material is applied only once, such that the coated edge 14a consists of a single polymer coating. Figure 1B As shown, the applied coating 90 may not be uniform.

[0029] The razor blade edge 72 may then be heated in a first heating step 16 to allow the coating 90 to adhere to the razor blade edge 72 and produce the edge 16a. The first heating step 16 may occur in two segments 16-1, 16-2. During the first segment 16-1, the razor blade edge 72 may be heated to a temperature of 500°F ± 50°F and may be maintained at that temperature for 40 seconds for a single edge blade (i.e., a blade having a single edge) and 80 seconds for a double edge blade (i.e., a blade having two edges). Then, during the second segment 16-2, the razor blade edge 72 may be heated to a temperature of 700°F ± 50°F or 745°F ± 50°F and may be maintained at that temperature for 40 seconds for a single edge blade and 80 seconds for a double edge blade to allow the coating 90 to adhere to the razor blade edge.

[0030] Typically, when the polymer coating 90 includes a polyfluorocarbon, the heating temperature should be at least 620°F so that it is above the melting temperature of the polyfluorocarbon in the polymer coating 90. Exceeding the melting point of the polyfluorocarbon in the polymer coating 90 improves the contact between the coating 90 and the underlying layer (e.g., protective layer 80) of the razor blade edge 72, which drives the bonding between the two coatings 80, 90 and increases the adhesion and durability of the polymer coating 90. As described below, heating can also help drive off components of the dispersion medium in which the polymer material is mixed. The heating temperature should generally not exceed about 770°F because the polyfluorocarbon in the polymer coating 90 can begin to decompose at this temperature.

[0031] After the first heating step 16 and before additional heating steps are performed, the razor blade edge 72 may optionally be cooled to room temperature, i.e., 68° F. to 77° F., to produce edge 18a at step 18. Cooling may help ensure that edge 18a has a similar temperature profile (compared to edge 14a) before being subjected to additional heating.

[0032] The razor blade edge 72 may be heated a second time in a second heating step 20 to produce the edge 20a. Similar to the first heating step 16, the second heating step occurs in two sections 20-1, 20-2. During the first section 20-1, the razor blade edge 72 may be heated to a temperature of 500°F ± 50°F and may be maintained at this temperature for 40 seconds for a single-edged blade and 80 seconds for a double-edged blade. Then, during the second section 20-2, the razor blade edge 72 may be heated to a temperature of 700°F ± 50°F or 745°F ± 50°F and may be maintained at this temperature for 40 seconds for a single-edged blade and 80 seconds for a double-edged blade. It has been demonstrated that performing the second heating step 20 further increases the bonding and adhesion of the polymer coating 90 and produces improved durability of the polymer coating 90.

[0033] After the second heating step 20, the razor blade edge 72 may be optionally cooled to room temperature at step 21 to produce the edge 21a. After the heating steps 16, 20, the razor blade edge 72 may be subjected to a post-treatment at step 22 to partially remove the polymer coating 90 and produce a final edge 22a having a uniform coating 100 at step 24. The treatment may be performed with a solvent and / or mechanical means. The solvent may be perfluoroperhydrophenanthrene (C 14 F 24 ). The treatment time can be adjusted as needed to remove more or less of the polymer coating 90. In some examples, the razor blade edge 72 can be treated with solvent for 2 minutes. The mechanical treatment process can be, for example, isostatic pressing. No additional application of polymer material or thinning of the polymer coating occurs between the first heating step 16 and the second heating step 20 or between any of the heating sections 16-1, 16-2 and 20-1, 20-2. The blade 22a can optionally be subjected to one or more additional post-application treatment steps (not shown) to remove any excess solvent. These steps will be described in more detail below.

[0034] Figure 2A and Figure 2B 30 is a flow chart of another method 30 of manufacturing a razor blade edge that involves a single two-stage heating step with a higher temperature first stage. As used herein, the term "single" refers to heating steps that are performed continuously, wherein the razor blade edge is heated at a temperature above room temperature without any intervening steps, such as cooling, application of polymer material, and / or removal of polymer material. The single heating step can occur as a single stage or multiple stages. The method 30 can begin by introducing 32 a razor blade edge 72. As shown in FIG. Figure 2B As shown, the razor blade edge 72 has a cutting edge 32a, which may optionally include one or more prior coatings deposited thereon. The cutting edge 32a may be substantially similar to Figure 1A The blade 12a in the embodiment may include a substrate 74, an interlayer 76, a hard coating layer 78 and a protective layer 80.

[0035] At step 34, a polymer material, such as a polyfluorocarbon, may be applied to the razor blade edge 72 to produce a coated edge 34a including a polymer coating 90. The polymer material may be applied as a dispersion of the polymer material in a dispersion medium. The polymer may be a polyfluorocarbon. In some examples, the polymer material is applied only once, such that the coated edge 34a consists of a single polymer coating. Figure 2B As shown, the applied coating 90 may not be uniform.

[0036] The razor blade edge 72 may then be heated in a single heating step 36 to allow the coating 90 to adhere to the razor blade edge 72 and produce the edge 36a. The heating step 36 may occur in two segments 36-1, 36-2. During the first segment 36-1, the razor blade edge 72 may be heated to a temperature of 600°F ± 50°F and may be maintained at that temperature for 40 seconds for a single edge blade and 80 seconds for a double edge blade. Then, during the second segment 16-2, the razor blade edge 72 may be heated to a temperature of 745°F ± 50°F and may be maintained at that temperature for 40 seconds for a single edge blade and 80 seconds for a double edge blade to allow the coating 90 to adhere to the razor blade edge. Figure 2A The temperature during the first stage 36-1 of the heating step 36 is higher than Figure 1A The temperature during the first segment 16-1, 20-1 of either of the heating steps 16, 20 in the heating step 36 is higher than the temperature during the second segment 36-2 of the heating step 36. This increase in temperature during the first segment 36-1 increases the total time that the razor blade edge 72 is at a sufficiently high temperature to achieve additional bonding and adhesion of the polymer coating 90 and results in improved durability of the polymer coating 90.

[0037] Typically, as described above, when polymer coating 90 includes a polyfluorocarbon, the heating temperature should be at least 620°F so that it is above the melting temperature of the polyfluorocarbon in polymer coating 90. The heating temperature should generally not exceed about 770°F because the polyfluorocarbon in polymer coating 90 may begin to decompose at this temperature.

[0038] After the heating step 36, the razor blade edge 72 may optionally be cooled to room temperature (ie, 68°F to 77°F) at step 38 to produce the cutting edge 38a.

[0039] After the heating step 36 or the optional cooling step 38, the razor blade edge 72 may be subjected to a post-application treatment at step 40 to partially remove the polymer coating 90 and produce a final edge 40a having a uniform coating 200 at step 42. The treatment may be performed with a solvent and / or mechanical means. The solvent may be perfluoroperhydrophenanthrene (C 14 F 24 ). The treatment time can be adjusted as needed to remove more or less of the polymer coating 90. In some examples, the razor blade edge 72 can be treated with the solvent for 2 minutes. The mechanical treatment process can be, for example, isostatic pressing. The blade 40a can optionally be subjected to one or more additional post-application treatment steps (not shown) to remove any excess solvent, after which the method can end, i.e., no additional polymer is applied and no additional heating or thinning of the polymer coating is performed. These steps will be described in more detail below.

[0040] Figure 3A and Figure 3B 1 is a flow chart of another method 50 for manufacturing a razor blade edge, the method involving uniform heating temperature. The method 50 may begin by introducing 52 a razor blade edge 72. Figure 3B As shown, the razor blade edge 72 has a cutting edge 52a, which may optionally include one or more prior coatings deposited thereon. The cutting edge 52a may be substantially similar to Figure 1A The blade 12a in the embodiment may include a substrate 74, an interlayer 76, a hard coating layer 78 and a protective layer 80.

[0041] At step 54, a polymer material, such as a polyfluorocarbon, may be applied to the razor blade edge 72 to produce a coated edge 54a including a polymer coating 90. The polymer material may be applied as a dispersion of the polymer material in a dispersion medium. The polymer may be a polyfluorocarbon. In some examples, the polymer material is applied only once, such that the coated edge 54a consists of a single polymer coating. Figure 3B As shown, the applied coating 90 may not be uniform.

[0042] The razor blade edge 72 may then be heated in a single heating step 56 to allow the coating 90 to adhere to the razor blade edge 72 and produce the edge 56a. When the polymer coating 90 comprises a polyfluorocarbon, the razor blade edge 72 may be heated to a temperature of 625°F to 750°F, preferably 700°F. In the heating step 56, the razor blade edge 72 may be maintained at the temperature for a predefined time to allow the coating 90 to adhere to the razor blade edge 72. In the heating step 56, the razor blade edge 72 may be maintained at the temperature for 80 seconds for a single edge blade and 160 seconds for a double edge blade. The heating step 56 may be considered to include two heating segments 56-1, 56-2, wherein the temperature in the first segment 56-1 is the same as the temperature during the second segment 56-2. Increasing the temperature in the first segment 56-1 increases the total time that the razor blade edge 72 is at a sufficiently high temperature to achieve additional bonding and adhesion of the polymer coating 90, and produces improved durability of the polymer coating 90.

[0043] Typically, as described above, the heating temperature should be at least 620°F so that it is above the melting temperature of the polyfluorocarbons in polymer coating 90. The heating temperature should typically not exceed about 770°F because the polyfluorocarbons in polymer coating 90 may begin to decompose at this temperature.

[0044] After the heating step 56, the razor blade edge 72 may optionally be cooled to room temperature (ie, 68°F to 77°F) at step 58 to produce the cutting edge 58a.

[0045] After the heating step 56 or the optional cooling step 58, the razor blade edge 72 may be subjected to a post-application treatment at step 60 to partially remove the polymer coating 90 and produce a final edge 60a having a uniform coating 300 at step 62. The treatment may be performed with a solvent and / or mechanical means. The solvent may be perfluoroperhydrophenanthrene (C 14 F 24 ). The treatment time can be adjusted as needed to remove more or less of the polymer coating 90. In some examples, the razor blade edge 72 can be treated with the solvent for 2 minutes. The mechanical treatment process can be, for example, isostatic pressing. The blade 60a can optionally be subjected to one or more additional post-application treatment steps (not shown) to remove any excess solvent. These steps will be described in more detail below.

[0046] The sintering thermal gradient can be tailored to the specific combination of edge profile (e.g., shape of the edge, including multiple facets, end radius, facet angles, etc.) and / or hard coating to optimize the durability or other properties of the PTFE coating. Different hard coating outer layers may exhibit different reactivity and / or bonding characteristics from the polymer coating, thus requiring implementation of a specific sintering temperature profile to achieve the desired blade design intent. For example, an outer coating comprising chromium diboride may need to be heated at a relatively cool temperature for a period of time to achieve optimal performance, while a chromium coating above the DLC hard coating may need to be heated at a relatively hot temperature for a similar period of time. A method of manufacturing a razor blade edge may include applying a single coating of a polymer material to a razor blade edge to form a coated blade edge, as described above with respect to methods 10, 30, and 50 and as described above with respect to methods 10, 30, and 50. Figure 1A , Figure 2A and Figure 3A , and selecting a temperature profile, wherein the temperature profile includes at least one temperature and at least one time, and wherein the temperature profile is selected based on the composition of the razor blade edge. For example, the temperature profile may include the times and / or temperatures described with respect to steps 16 to 20 in method 10, step 36 in method 30, or step 56 in method 50. The coated edge is then heated at a temperature indicated by the selected temperature profile for a time indicated by the selected temperature profile to adhere the polymeric material to the razor blade edge, and then optionally, treated with a solvent or mechanical method to partially remove the coating, as described herein.

[0047] Figure 44 is a block flow diagram of a system 400 that can be used to manufacture treated razor blades according to the present disclosure. A coating chamber 414 can be used to apply one or more coatings of a coating material 490 to one or more portions of a plurality of razor blades 470, such as cutting edges 472 of the razor blades 470. As shown, the razor blades 470 can be located within the chamber 414 so that the coating material 490 is applied using one or more techniques described in detail below. The system 400 may include a chamber for a first heating step 416, and may optionally include a chamber for a second heating step 420, as described below. The system 400 may also optionally include an additional chamber 422 for performing different coating techniques and / or performing different post-application treatments.

[0048] Applying coating material

[0049] According to the present disclosure, coating material 490 may include polymeric materials and may include dispersions of polymeric materials in a dispersion medium. The polymeric material may be a fluorocarbon polymer (also referred to herein as polyfluorocarbon). Preferred fluorocarbon polymers (i.e., starting materials) may contain carbon atom chains, including dominant -CF2-CF2- groups, such as polymers of tetrafluoroethylene, including copolymers, such as those of hexafluoropropylene with a small proportion (e.g., up to 5% by weight). These polymers may have end groups at the ends of the carbon chains, and the properties of the end groups may vary according to the method for preparing the polymer, which is well known. Common end groups of such polymers are: -H, -COOH, -Cl, -CCl3, -CFClCF2Cl, -CH2OH, -CH3, etc. Preferred polymers of the present disclosure may have an average molecular weight of about 700 g / mol to about 4,000,000 g / mol, preferably about 22,000 g / mol to about 200,000 g / mol.

[0050] The most preferred fluorocarbon polymer (ie, starting material) is polytetrafluoroethylene (PTFE). Figure 1A , Figure 2A and Figure 3A The coating steps 14, 34, 54 in the embodiment may use PTFE having an average molecular weight of greater than about 200,000 g / mol to about 4,000,000 g / mol. Alternatively, the PTFE of the coating steps 14, 34, 54 may have an average molecular weight of about 3,000 g / mol to about 200,000 g / mol.

[0051] In addition, the present disclosure contemplates Figure 1A , Figure 2A and Figure 3A The resulting polyfluorocarbon coating after one or more of the heating steps 16, 20, 36, 56 may include PTFE having a resulting thickness of less than about 0.5 microns.

[0052] In an alternative embodiment, the present disclosure contemplates that the resulting polyfluorocarbon coating after one or more of the heating steps 16, 20, 36, 56 may include PTFE having a resulting thickness greater than about 0.5 microns, more preferably approaching or greater than about 1.0 microns. In particular, heated polyfluorocarbon coatings that are significantly thicker than prior art polyfluorocarbon coatings (e.g., U.S. Pat. No. 5,985,459) have particular applications where skin comfort and / or reduced cutting forces with use may be desired.

[0053] As described below, coatings according to the present disclosure may be Figure 1A , Figure 2A and Figure 3A The solvent treatment is performed at steps 22, 40, 60 in the process, thereby further enhancing the shaving characteristics, such as reducing the cutting force. In addition, the present disclosure contemplates that the polyfluorocarbon coating obtained after steps 22, 40, 60 may include PTFE having a thickness less than or equal to about 0.2 microns.

[0054] Preferred commercial polyfluorocarbons may include those manufactured by Chemours TM Made of materials such as Chemours TM Fluorine additive powders and / or dispersions (e.g., MP1100, MP1200, MP1600, and MPD1700) or Chemours TM Such as LW-2120 or RA series.

[0055] The polyfluorocarbon dispersion according to the present disclosure may comprise 0.05% to 10% by weight, preferably 0.5% to 2% by weight, of a polyfluorocarbon dispersed in a dispersant medium. The polymer dispersion may be introduced directly into the flow stream, or the polymer powder may be mixed into the dispersion medium and subsequently homogenized prior to introduction into the flow stream. In order to form a dispersion to be sprayed onto the blade 472, the polyfluorocarbon should have a very small submicron particle size. The dispersion medium is typically selected from the group consisting of: fluorocarbons (e.g., from Chemours TM Freon brand), moisture, volatile organic compounds (e.g., isopropyl alcohol), and supercritical CO2. Water is most preferred.

[0056] The dispersion can be applied to the blade 472 in any suitable manner to provide a coating as uniform as possible, such as, for example, spraying, dipping, brushing, isostatic pressing, molding, vacuum deposition, printing, application via a pad or coating, inkjet nozzles, 3D printing, or any combination thereof, any of which may or may not include masking one or more portions of the razor blade 470. Spraying is particularly preferred for coating the blade 472, in which case an electrostatic field may be used in conjunction with spraying to increase deposition efficiency. Preheating of the dispersion may be desirable to facilitate spraying, wherein the degree of preheating depends on the properties of the dispersion. It may also be desirable to preheat the blade 470 to a temperature close to or greater than the boiling point of the dispersant medium.

[0057] Heating and Cooling

[0058] See also Figure 4 , the heating chamber 416 can be used to heat the coated razor blades carried on the chain (not shown). Chamber 416 can be heated to a set temperature, and the coated blades are kept in chamber 416 for a set time. Specifically, the time in chamber 416 can be determined at least in part by the length of chamber 416 and the speed of the chain. The coated blades can then be optionally cooled to room temperature in a separate chamber (not shown). In the case of a method involving multiple heating steps and / or heating sections as described herein, the coated blades can be optionally placed in a second heating chamber 420, which can be heated to a set temperature, and the coated blades are kept in chamber 420 for a set time. Alternatively, some or all of the heating steps and / or heating sections can be performed in the first heating chamber 416. Additional cooling steps can then be performed in a separate chamber (not shown).

[0059] Typically, the blade carrying the deposited polymer particles on its blade edge should be heated at an elevated temperature to form an adherent coating on the blade edge and to drive off the dispersant medium. The coated blade is preferably heated in an atmosphere of an inert gas such as helium, argon, nitrogen, etc., or in an atmosphere of a reducing gas such as hydrogen, or in a mixture of such gases, or in a vacuum. The heating must be sufficient to allow at least sintering of the individual particles of the polymer. Preferably, the heating should be sufficient to allow the polymer to spread into a substantially continuous film of appropriate thickness and to allow the polymer to become firmly adhered to the blade material.

[0060] therefore, Figure 1A , Figure 2A and Figure 3AThe heating of the coating at steps 16, 20, 36, 56 in the embodiment of the present invention is intended to cause the polymer to adhere to the blade. The heating operation can produce a sintered, partially melted or fully melted coating. A partially melted or fully melted coating is preferred because it allows the coating to spread and cover the blade more thoroughly. For a more detailed discussion of melting, partial melting and sintering, see McGraw-Hill Encyclopedia of Science and Technology, Vol. 12, 5th Edition, p. 437 (1992). The heating conditions, i.e., maximum temperature, length of time, etc., should generally be adjusted to avoid significant decomposition of the polymer and / or excessive tempering of the metal of the blade.

[0061] Apply post-processing

[0062] After heating, the coated blade may optionally be treated in a post-treatment chamber 422, such as Figure 4 The treatment can be performed with solvent and / or mechanical methods. The solvent treatment partially removes the polyfluorocarbon coating that was originally deposited on the blade surface and heated on the blade surface. The removed portion of the polyfluorocarbon coating can generally be referred to as the "non-adherent" soluble polymer molecules of the coating.

[0063] Solvents are typically selected based on their polyfluorocarbon solvency, being liquid at the dissolution temperature and / or having low polarity. These parameters are described in U.S. Patent No. 5,985,459. After the blade has been solvent treated as described above, the blade may be subjected to additional treatment to remove any excess solvent. The treatment may be carried out, for example, by immersing the blade in a washing solution for the solvent. Preferably, the washing solution should be able to be easily separated from the solvent. Alternatively, the coated blade may be treated mechanically, such as isostatic pressing.

[0064] refer to Figure 5 , one or more razor blades 70 including a razor edge 72 having a uniform coating may be incorporated into a razor cartridge 500, which may include a housing 510 having a guard structure 520 and a cap structure 530. The cap structure 530 may include a shaving aid 540 in the form of one or more lubricating and / or moisturizing strips. The razor cartridge 500 may be used integrally with a handle in a disposable razor, wherein when the blade becomes dull, the entire razor is discarded as an integral unit, or may include a removable razor cartridge that forms part of a shaving system, wherein the removable razor cartridge is separated from the razor handle and disposed of, and a new removable razor cartridge is coupled to the same handle.

[0065] Blade Preparation Example - Uniform Temperature Sintering

[0066] A batch of blades was sprayed, heated, and solvent treated as follows:

[0067] 1. Set the fixture holding the blade on a stand. Pass the fixture through a chamber where the blade edge is sprayed with an aqueous dispersion of fluorocarbon.

[0068] 2. The fixture was then passed through a heating chamber for a heating step consisting of two stages, with each stage having a temperature set at 700°F.

[0069] 3. The blade was then solvent treated in perfluoroperhydrophenanthrene at greater than about 500°F at a pressure at or above about 60 PSI for about 2 minutes.

[0070] 4. Collect blade samples.

[0071] Figure 6 A graph 600 of time at temperature is provided for a blade made using the exemplary method described above (labeled Low Cutting Force (LCF) Uniform, 630) compared to a blade made using a sintering process in which the first heating section of the heating chamber is set to 500°F and the second heating section of the heating chamber is set to above 700°F (labeled LCF Conventional, 620). Figure 6 As shown, the above manufacturing process increases the time at the required sintering temperature. Specifically, the temperature profile shows that the LCF uniform blade 630 made using the uniform temperature sintering process is maintained at a temperature above the melting point of the PTFE dispersion (about 620°F, 610°C) for about 30 more seconds than the LCF conventional blade 620 made using the conventional sintering process.

[0072] The uniform temperature process of the present invention results in improved durability. In particular, it is believed that the improved coating durability and overall blade performance of coated blades according to the present disclosure can be attributed at least in part to ensuring that the blade is at the target processing temperature (i.e., a temperature at or above the melting point of the coating material) for a sufficient amount of time to allow adequate adhesion between the coating and the underlying layers.

[0073] like Figure 6As shown, the LCF conventional coated blade 620 reaches a temperature at or near the target processing temperature at the end of the process shortly before leaving the sintering chamber, so that the coated blade is at or near the target temperature for only a short period of time. Since the time at temperature is considered to be critical for achieving a strong bond between the coating and the underlying layer, the method of the present disclosure provides improved blade characteristics and performance. Simply increasing the processing temperature can cause the coating to degrade and can increase blade tempering and reduce edge strength. The method disclosed in the present invention involves heating at a lower temperature for a longer time and / or heating at a higher temperature in stages, both of which can reduce blade tempering and produce a stronger blade edge that is less prone to edge damage. In addition, the method disclosed herein does not require a second polyfluorocarbon coating, nor does it require a second processing step to partially remove the second polyfluorocarbon coating, which saves material and time. The method according to the present disclosure involves two heating sections, which are performed successively without any intervening steps (e.g., no additional coating or thinning steps). In addition, the final razor blade edge has enhanced durability, which leads to improved and more consistent shaving performance.

[0074] test

[0075] Testing was conducted to determine how the durability of blades made according to the inventive method of the present disclosure compares to blades made according to a standard control production method and an alternative production method, both of which are known in the art. Comparative blade samples (Samples 1 and 2) were made using the various production methods listed in Table 1 below. Inventive blade samples (Samples 3 and 4) were made using the inventive method of the present disclosure described below, with the Sample 4 blade being made using a process in which the first heating stage and the second heating stage occurred at about 745°F (uniform temperature, UT). Inventive blade samples and comparative blade samples were made using a sharp steel substrate having a Nb / DLC / Cr hard coating.

[0076] Table 1: Comparison of blade production methods

[0077] Sample No. Production method Sample 1 (comparison) <![CDATA[Standard sintered / thin uniform telomer (TUT) 1 > Sample 2 (comparison) <![CDATA[Re-spray / Sinter / Thin Uniform Telomer (RSST) 2 > Sample 3 (Invention) <![CDATA[Re-Sintered / Thin Homogeneous Telomer (RST) 3 > Sample 4 (Invention) <![CDATA[Uniform Temperature / Thin Uniform Telomer (UT) 4 >

[0078] 1Described in U.S. Pat. No. 5,985,459

[0079] 2 Described in U.S. Pat. No. 10,118,304

[0080] 3 About Figure 1A and Figure 1B Give a description.

[0081] 4 About Figure 3A and Figure 3B Give a description.

[0082] The blades were tested to determine the durability of the coating, specifically comparing the blades before 500 cuts (CF 之前 ) and after (CF 之后 ) cutting force, where the cutting force is expressed in pounds (lbs) of cutting force in wool felt. The difference in blade cutting force CF before and after 500 wool felt cuts 之后 -CF 之前 It is defined as the delta cut force, and generally the lower the delta cut force, the greater the durability of the fluorocarbon coating (eg, PTFE telomer). Fig. 7A 700A is a graph of the average Δ cutting force values ​​for each set of blades. Fig. 7A As shown and listed in Table 2, the RST process and single-pass UT sintering process used to prepare the Sample 3 and Sample 4 inserts provide greater durability and lower Δ cutting force compared to the Sample 1 insert. The Sample 3 and Sample 4 inserts show durability similar to that of the Sample 2 insert prepared using the more complex RSST method. In particular, the RST process and UT process eliminate the need for additional processing involved in applying the polyfluorocarbon coating a second time in the RSST process, which can reduce cost and production time while still providing similar durability.

[0083] Table 2: Δ Cutting Force (lbs) values ​​(CF) for different sintering processes 之后 -CF 之前 )

[0084]

[0085] When using the uniform temperature method (see above for Figure 3A and Figure 3B Additional testing was performed on chromium diboride coated inserts prepared as described above, wherein the sintering process occurred at different temperatures listed below in Table 3. The inserts were then subjected to durability testing similar to that described above.

[0086] Table 3: Comparison of blade sintering temperatures

[0087] Sample No. Uniform sintering temperature (℉) Sample 5 675 Sample 6 700 Sample 7 720 Sample 8 745

[0088] Figure 7B is the average Δ cutting force value (CF 之后 -CF 之前 ) of FIG700B. Figure 7BAs shown and listed in Table 4, the lower temperature sintering process (Samples 5 and 6) has better durability for the CrB2 coated inserts than the high temperature sintering process (Samples 7 and 8). As mentioned above, generally the lower the delta cutting force, the greater the durability of the fluorocarbon coating. Therefore, as the sintering process temperature increases, the durability appears to decrease. Therefore, the sintering temperature profile can be optimized for a specific insert / coating type.

[0089] Table 4: Δ cutting force (lbs) values ​​for different sintering temperatures

[0090]

[0091] The representative embodiments of the present disclosure described above can be described as follows:

[0092] A. A method of manufacturing a razor blade edge, the method comprising:

[0093] a) applying a single coating of a polymeric material to said razor blade edge to form a coated edge; and

[0094] b) performing a single heating of the coated cutting edge to adhere the polymeric material to the razor blade cutting edge, wherein the single heating of the coated cutting edge comprises a first heating segment and a second heating segment.

[0095] B. The method according to paragraph A, wherein the second heating stage is carried out at a higher temperature than the first heating stage.

[0096] C. A method according to paragraph B, wherein:

[0097] The first heating stage is conducted at a temperature between 500°F and 795°F, wherein the first heating stage lasts for at least 40 seconds; and

[0098] The second heating stage is conducted at a temperature between 500°F and 795°F, wherein the second heating stage lasts for at least 40 seconds.

[0099] D. The method of paragraphs B or C, wherein the first heating segment is conducted at a temperature of 600°F for at least 40 seconds, and wherein the second heating segment is conducted at a temperature of 745°F for at least 40 seconds.

[0100] E. The method of any of paragraphs A to D, wherein applying the coating of the polymeric material comprises applying a dispersion of the polymeric material in a dispersion medium.

[0101] F. The method of paragraph E, wherein the polymeric material comprises a polyfluorocarbon.

[0102] G. The method of paragraph F, wherein the polyfluorocarbon comprises polytetrafluoroethylene.

[0103] H. The method of any of paragraphs A to G, further comprising cooling the coated blade edge after the single heating of the coated blade edge.

[0104] I. The method of paragraph H, wherein the coated blade edge is cooled to room temperature.

[0105] J. The method according to paragraphs A to I, further comprising treating the coated blade with a solvent or a mechanical method to partially remove the coating.

[0106] K. A method according to any of paragraphs J, wherein the solvent comprises perfluoroperhydrophenanthrene (C 14 F 24 ).

[0107] L. The method of any of paragraphs A to K, wherein the mechanical method comprises isostatic pressing.

[0108] M. A razor blade edge produced according to the method of any of paragraphs A to L.

[0109] The illustrations presented herein are not intended to be actual views of any particular substrate, apparatus (eg, device, system, etc.), or method, but are merely idealized and / or schematic representations used to describe and illustrate various embodiments of the present disclosure.

[0110] The dimensions and values ​​disclosed herein should not be understood as being strictly limited to the exact numerical values ​​cited. Instead, unless otherwise specified, each such dimension is intended to represent the stated value and a functionally equivalent range around that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm" or ±10% of the disclosed dimension.

[0111] Unless expressly excluded or otherwise limited, each document cited herein, including any cross-referenced or related patent or patent application and any patent application or patent to which this application claims priority or the benefit of, is hereby incorporated by reference in its entirety. The citation of any document is not an admission that it is prior art to any of the present invention disclosed or claimed herein, or an admission that it, by itself or in combination with any one or more of the references, proposes, suggests, or discloses any such invention. In addition, to the extent that any meaning or definition of a term in this invention conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this invention shall govern.

[0112] Although specific embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications may be made without departing from the spirit and scope of the present invention. Therefore, it is intended that all such changes and modifications within the scope of the present invention be covered in the appended claims.

Claims

1. A method of manufacturing a razor blade edge, the method comprising: a) applying a single coating of a polymeric material to said razor blade edge to form a coated edge; as well as b) performing a single heating of the coated cutting edge to adhere the polymeric material to the razor blade cutting edge, wherein the single heating of the coated cutting edge comprises a first heating segment and a second heating segment.

2. The method of claim 1, wherein the second heating stage is performed at a higher temperature than the first heating stage.

3. The method according to claim 1 or 2, wherein: The first heating stage is conducted at a temperature between 500°F and 795°F, wherein the first heating stage lasts for at least 40 seconds; and The second heating stage is conducted at a temperature between 500°F and 795°F, wherein the second heating stage lasts for at least 40 seconds.

4. The method of claim 3, wherein the first heating stage is conducted at a temperature of 600°F for at least 40 seconds, and wherein the second heating stage is conducted at a temperature of 745°F for at least 40 seconds.

5. The method of any one of the preceding claims, wherein applying the coating of the polymeric material comprises applying a dispersion of the polymeric material in a dispersion medium. The method of claim 5 , wherein the polymer material comprises a polyfluorocarbon.

7. The method of claim 6, wherein the polyfluorocarbon comprises polytetrafluoroethylene.

8. The method of any one of the preceding claims, further comprising cooling the coated blade edge after the single heating of the coated blade edge.

9. The method of claim 8, wherein the coated blade is cooled to room temperature.

10. The method of any one of the preceding claims, further comprising treating the coated blade with a solvent or mechanical means to partially remove the coating.

11. The method according to claim 10, wherein the solvent comprises perfluoroperhydrophenanthrene (C 14 F 24 ).

12. The method of claim 10, wherein the mechanical method comprises isostatic pressing.

13. A razor blade edge produced according to the method of any preceding claim.

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