Razor blades containing parylene and titanium

Abstract

This disclosure relates to a razor blade comprising a first layer containing titanium and a second layer containing parylene. This disclosure also relates to a razor cartridge comprising at least one razor blade comprising a first layer containing titanium and a second layer containing parylene. This disclosure further relates to a method for coating a razor blade with a first layer containing titanium and a second layer containing parylene.

Description

Technical Field

[0001] (Cross - reference to related applications) This application claims the priority of European Patent Application Publication No. 23174334.5, filed on May 19, 2023, the entire content of which is incorporated herein by reference.

[0002] (Field of the Invention) The present invention relates to the field of razor blades. More specifically, the present invention relates to razor blades including a lubricating layer.

Background Art

[0003] A razor head (also known as a safety razor head, razor cartridge, or safety razor cartridge) is typically part of a shaving razor assembly that includes a razor handle. The razor head generally comprises one or more cutting members, each cutting member including a razor blade, which is disposed between the longitudinal front face and the longitudinal rear face of the razor head. In use, the user holds the razor handle in the shaving direction and brings the razor head into contact with a portion of the skin. By moving the razor head in the shaving direction, unwanted hair is removed.

[0004] Razor blades for razor cartridges typically contain a lubricating layer. This lubricating layer is usually applied by a coating and is sometimes called a lubricating coating. The lubricating layer is designed to reduce the cutting force required during the shaving process. By reducing the required cutting force, the razor glides more smoothly during the shaving motion, making it easier to use. In addition, reducing the required cutting force can reduce hair pulling and the resulting pulling of hair follicles, which can cause discomfort to the user. Furthermore, the lubricating coating can also reduce friction between the razor blade and the user's skin, which also improves the razor's glide. Moreover, the reduced cutting force and improved glide can result in a better shaving result, for example, with less stubble, cuts, and nicks.

[0005] Generally, the lubricating coating on razor blades is made from perfluoroalkyl substances such as polytetrafluoroethylene (PTFE) or polyfluoroalkyl substances (PFAS). PTFE-coated razor blades are effective at cutting hair, causing little friction to the skin and low pulling on the hair.

[0006] However, PTFE coatings also have drawbacks. First, PTFE coatings are generally applied by spraying PTFE particles onto the razor blade and then sintering the sprayed particles at a temperature exceeding the melting point of PTFE. The resulting coating may lack uniformity, which can lead to a decrease in the shaving performance of the razor blade. Furthermore, the temperature rise during the sintering process can reduce the hardness and corrosion resistance of the razor blade. In addition, because PTFE is a material that is very difficult to decompose, it is a subject of environmental concern.

[0007] This disclosure aims to address one or more of the aforementioned problems regarding the optimization of lubrication layers. [Overview of the project]

[0008] In a first aspect, the disclosure relates to a razor blade comprising a first layer containing titanium and a second layer containing parylene.

[0009] In some embodiments, the first layer may contain titanium as metallic titanium.

[0010] In some embodiments, parylene may be selected from the group consisting of parylene-N, parylene-C, parylene-F, and combinations thereof, and in particular, parylene may be selected from parylene-N and / or parylene-C.

[0011] In some embodiments, the razor blade may have a tip edge, and the first and second layers may be provided on the tip edge.

[0012] In some embodiments, the razor blade may be configured to be located within a razor cartridge.

[0013] In some embodiments, the first layer may have a thickness of about 5 nm to about 70 nm, more specifically, about 10 nm to about 60 nm, and in particular about 20 nm to about 50 nm.

[0014] In some embodiments, the second layer may have a thickness of about 0.005 μm to about 5 μm, more specifically, about 0.02 μm to about 2 μm, and in particular about 0.1 μm to about 1 μm.

[0015] In some embodiments, the second layer does not have to contain pores, and in particular does not have to contain pores having a diameter of about 5 nm to about 200 nm.

[0016] In some embodiments, the second layer may contain less than 1% by weight, more specifically less than 0.1% by weight of polytetrafluoroethylene, and may not contain polytetrafluoroethylene at all, or may be substantially free of it.

[0017] In some embodiments, the razor blade may be further provided with a hard coating.

[0018] In some embodiments, the hard coating may include ceramic, metallic, and / or non-metallic coatings.

[0019] In some embodiments, the ceramic may include borides and / or carbides, and in particular titanium diboride.

[0020] In some embodiments, the ceramic may contain titanium, boron, and carbon.

[0021] In some embodiments, the non-metallic coating may include diamond-like carbon.

[0022] In some embodiments, the hard coating metal may contain chromium.

[0023] In some embodiments, the first layer may be placed between the hard coating and the second layer.

[0024] In some embodiments, the first layer may be provided directly on the razor blade. Alternatively, in some embodiments, the hard coating may be provided directly on the razor blade. Alternatively, in some embodiments, an intermediate layer may be provided on the razor blade, and the hard coating may be provided on the intermediate layer. In some embodiments, the intermediate layer may include a metal, more specifically niobium and / or titanium, even more specifically titanium, and in particular metallic titanium.

[0025] In some embodiments, the razor blade may comprise metal, particularly stainless steel, consist essentially of metal, or be made of metal.

[0026] In some embodiments, the cross-section of the tip edge may have a substantially symmetric tapered shape terminating at the cutting edge, the cross-section may have a central longitudinal axis starting from the cutting edge, and the tip edge may have a thickness of 1.5 μm to 2.4 μm measured at a distance of 5 μm along the central longitudinal axis from the cutting edge.

[0027] In a second aspect, the present disclosure relates to a razor cartridge comprising at least one razor blade as described in any of the preceding claims.

[0028] In a third aspect, the present disclosure relates to a method for coating a razor blade. The method includes coating the razor blade with a first layer containing titanium, more specifically by physical vapor deposition, and coating the razor blade with a second layer containing parylene, more specifically by chemical vapor deposition.

[0029] In some embodiments, coating the razor blade with titanium may be performed before coating the razor blade with parylene.

[0030] In some embodiments, coating the razor blade with the first layer containing titanium may be performed by sputtering.

[0031] In some embodiments, coating the razor blade with parylene by chemical vapor deposition may include sublimating a dimer of the parylene precursor, pyrolyzing the sublimated dimer of the parylene precursor to obtain a monomer of the parylene precursor, and depositing the monomer of the parylene precursor on the razor blade.

[0032] In some embodiments, the sublimation of the parylene precursor dimer may be carried out at a temperature of about 130°C to about 190°C, more specifically about 150°C to about 180°C, and / or at a pressure of about 0.5 Torr to about 2 Torr, more specifically about 0.8 Torr to about 1.2 Torr.

[0033] In some embodiments, the thermal decomposition of the sublimated parylene precursor dimer may be carried out at a temperature of about 400°C to about 800°C, more specifically about 500°C to about 700°C, and / or at a pressure of about 0.2 Torr to about 1 Torr, more specifically about 0.4 Torr to about 0.6 Torr.

[0034] In some embodiments, the deposition of parylene precursor monomers may be carried out at a temperature of about 10°C to about 50°C, more specifically about 17°C to about 28°C, and / or at a pressure of about 0.01 Torr to about 0.5 Torr, more specifically about 0.05 Torr to about 0.2 Torr.

[0035] In some embodiments, the method for coating the razor blade may further include an annealing step, in particular the razor blade may be annealed in an inert gas atmosphere at a temperature of about 300°C to about 400°C, more specifically at a temperature of about 330°C to about 370°C, especially after the deposition of parylene.

[0036] In some embodiments, the razor blade may be annealed for a duration of about 10 seconds to about 20 minutes, more specifically for a duration of about 1 minute to about 5 minutes. [Brief explanation of the drawing]

[0037] [Figure 1] This is a schematic diagram of a cross-sectional view of the edge of a razor blade, in which the first and second layers are provided on the edge of the blade. [Figure 2] This is a schematic diagram of a cross-sectional view of the edge of a razor blade, in which the first and second layers are provided on the edge of the blade above the hard coating and the intermediate layer. [Figure 3]This is a schematic diagram of a cross-sectional view of the edge of a razor blade, in which the first sub-layer and the second sub-layer are provided on the edge of the blade on top of the first coating and the hard coating. [Figure 4] This shows a comparison of the cutting force between the third sample lot and the first comparative sample lot. [Figure 5] This shows a comparison of the cutting forces of the first, second, third, and fourth sample lots. [Figure 6] This shows a comparison of the cutting force between the third and fifth sample lots. [Figure 7] This shows a comparison of the frictional force of the second sample lot compared to the second comparative sample lot. [Figure 8] This shows a comparison of the cutting force between the sixth sample lot and the third comparative sample lot. [Modes for carrying out the invention]

[0038] The present disclosure is described in detail below. Terms or words used in the description and embodiments of this disclosure should not be construed to be limited to their general language or dictionary meanings, but should be construed to have their ordinary technical meanings as established in the art, unless otherwise defined in the following description. The detailed description refers to specific embodiments to better illustrate this disclosure, but it should be understood that the presented disclosure is not limited to these specific embodiments.

[0039] As mentioned above, the lubricating coating on razor blades is generally made of perfluoroalkyl substances such as polytetrafluoroethylene (PTFE) or polyfluoroalkyl substances (PFAS) because PTFE-coated razor blades are effective at cutting hair, cause little friction to the skin, and have a low degree of pulling on the hair.

[0040] However, PTFE coatings can lack uniformity as a result of deposition due to particle spraying, which can lead to a decrease in the shaving performance of razor blades. Furthermore, the (prolonged) temperature rise during the sintering process can reduce the hardness and corrosion resistance of the razor blades. In addition, PTFE is a material that is very difficult to decompose, making it a subject of environmental concern.

[0041] A currently known alternative to PTFE coatings (or any other PFAS coating) is a coating containing a polymer selected from the parylene group, which also exhibits a low coefficient of friction. However, parylene coatings may lack sufficient adhesion to razor blades.

[0042] Surprisingly, it was discovered that the adhesion of parylene could be improved by first depositing titanium onto the razor blade, and then depositing parylene onto the razor blade.

[0043] Accordingly, in a first embodiment, the present disclosure relates to a razor blade comprising a first layer containing titanium and a second layer containing parylene. The razor blade according to the first embodiment exhibits low cutting force. Cutting force is a measure of the amount of force required to cut hair.

[0044] Therefore, surprisingly, it was found that, in addition to improving adhesion, using the first layer containing titanium could reduce the required cutting force.

[0045] The adhesion of PTFE coating to razor blades is generally achieved by using a chromium coating. However, it is known that parylene adheres poorly to chromium, which can increase the required cutting force. This increase in required cutting force may be due to the parylene coating peeling off the razor blade during shaving. When parylene is applied to chromium, peeling may occur as early as the first shave, whereas when parylene is applied to titanium, peeling may occur only gradually. Surprisingly, it has been found that, in contrast to chromium, the adhesion of parylene, by providing a layer of titanium, can substantially reduce the required cutting force of the razor blade.

[0046] In some embodiments, the first layer may contain titanium as metallic titanium. Metallic titanium may be particularly suitable for parylene bonding. The term “metallic titanium” is well known and, in particular, is considered to have a general meaning in the art. Additionally or alternatively, the term “metallic titanium” may refer to the reduced state of titanium, where its oxidation state is 0. Additionally or alternatively, the term “metallic titanium” may refer to titanium atoms contained in the first layer that form metallic bonds with one another. In some embodiments, the first layer may consist of titanium (as detailed above) or be essentially titanium.

[0047] In some embodiments, parylene may be selected from the group consisting of parylene-N, parylene-C, parylene-F, and combinations thereof. In particular, in some embodiments, parylene may be selected from parylene-N and / or parylene-C. Surprisingly, it has been found that a second layer containing parylene-N can reduce the cutting force compared to other parylenes. However, a second layer containing parylene-C can reduce the cutting force after multiple uses of the razor blade compared to parylene-N.

[0048] In some embodiments, the second layer may consist of parylene (as detailed above) or be essentially parylene.

[0049] The term "parylene" refers to a polymer whose skeleton consists of a para-benzenediyl ring-C6H4 linked by 1,2-ethanediyl crosslinks-CH2-CH2-. Different types of parylene can be obtained by substituting the para-benzenediyl ring.

[0050] Parylene-N (or parylene-N) is an unsubstituted parylene. Parylene-N can be obtained by polymerization of paraxylylene. Parylene-N consists of the following repeating units.

[0051] [ka]

[0052] Parylene-C (or parylene-C) is chlorinated parylene. Parylene-C can be obtained by polymerization of 2,8-dichlorotricyclo[8.2.2.24,7]hexadeca-1(12),4,6,10,13,15-hexaene. Parylene-C consists of the following repeating units.

[0053] [ka]

[0054] Parylene-F (or parylene-F) is a fluorinated parylene, in which four hydrogen atoms on the aryl ring are substituted with fluorine. Parylene-F can be obtained by polymerization of 4,5,7,8,12,13,15,16-octafluoro[2.2]paracyclophane. Parylene-F consists of the following repeating units:

[0055] [ka]

[0056] Furthermore, surprisingly, it was found that the combination of parylene-C and parylene-N could reduce the cutting force compared to either a second layer containing parylene-C or a second layer containing parylene-N. In particular, the second layer may include a first sublayer containing parylene-C and a second sublayer containing parylene-N. In some embodiments, the first sublayer containing parylene-C may be provided on the first layer, and the second sublayer containing parylene-N may be provided on the first sublayer. In some alternative embodiments, the first sublayer may contain parylene-N and the second sublayer may contain parylene-C.

[0057] In some embodiments, the razor blade may include a metal, particularly stainless steel, or be essentially made of a metal, particularly stainless steel, or be made of a metal, particularly stainless steel. Stainless steel razor blades can exhibit high strength, hardness, and corrosion resistance. Furthermore, stainless steel razor blades can be processed more easily than, for example, ceramic razor blades. The razor blade may be polished to form a rim. More specifically, the razor blade may be shaped to terminate at a tip rim having substrate sides converging toward the substrate edge. Thus, in some embodiments, the razor blade may have a tip rim, and the first and second layers may be provided on the tip rim. As described above, the second layer, which includes parylene, may be configured to function as a lubricating coating. The lubricating coating can improve hair cutting by the razor blade. Thus, it may be beneficial to provide at least the first and second layers on the tip rim.

[0058] When referring to a tip edge comprising a first and a second layer, it should be understood that such a reference refers not merely to the exact geometric edge of the razor blade, but rather to the edge considering the cutting action performed by the razor blade. Therefore, the term tip edge also means to include the portion of the razor blade side surface directly adjacent to the exact geometric edge of the tip edge. In exemplary embodiments, the region forming the tip edge extends along the central longitudinal axis of the tip edge, away from the exact geometric edge of the tip edge, over distances of approximately 5 μm or less, approximately 10 μm or less, approximately 15 μm or less, approximately 25 μm or less, approximately 50 μm or less, approximately 75 μm or less, approximately 100 μm or less, approximately 125 μm or less, approximately 150 μm or less, approximately 175 μm or less, or approximately 200 μm or less. The first and / or second layers may generally follow the surface and contour of the tip edge in the underlying layer. In particular, the second layer may form the outermost layer positioned on the razor blade. Therefore, the second layer may form the edge of the blade.

[0059] In some embodiments, the first layer may have a thickness of about 5 nm to about 70 nm, more specifically, about 10 nm to about 60 nm, and in particular about 20 nm to about 50 nm. In some embodiments, the second layer may have a thickness of about 0.005 μm to about 5 μm, more specifically, about 0.02 μm to about 2 μm, and in particular about 0.1 μm to about 1 μm.

[0060] In some embodiments, the razor blade may be configured to be placed inside a razor cartridge. The use of a lubricating coating, such as a second layer, may be particularly beneficial for razor blades used in razor cartridges.

[0061] In some embodiments, the razor blade may be further provided with a hard coating. The hard coating improves the hardness of the razor blade, thereby improving the blade's durability, particularly its service life. In some embodiments, the hard coating may include ceramic, metallic, and / or non-metallic coatings. In some embodiments, the ceramic may include borides and / or carbides, and in particular titanium diboride. In some embodiments, the ceramic may include titanium, boron, and carbon. In some embodiments, the metallic hard coating may include chromium. In some embodiments, the non-metallic coating may include diamond-like carbon.

[0062] When referring to hard coatings, it should be understood that the coating itself may be harder than the coated tip edge, and / or the coated tip edge may be hardened as a whole compared to the uncoated substrate. The hardness of a hard coating or coated tip edge can be measured using a nanoindenter. During the nanoindentation process, a hard tip with known properties (mechanical properties, shape, tip radius, etc.) penetrates a sample of the hard coating to be analyzed. For example, a Berkovich indenter can be used for the intent test. The load applied to the tip of the indenter was increased as the tip penetrated further into the specimen until a penetration depth of 50-100 nm was reached. At this point, the load was held for a certain period of time, and then the indenter was removed. The area of ​​the residual indentation in the sample was measured. Hardness H is defined as the maximum load P. max It is defined as the result of dividing by the residual depression area A.

[0063]

number

[0064] In some embodiments, the hard coating or tip edge may exhibit a hardness of about 5 GPa to about 30 GPa, more specifically about 10 GPa to about 20 GPa.

[0065] In some embodiments, the first layer may be positioned between the hard coating and the second layer. As described above, the second layer may form the outermost layer provided on the razor blade. Therefore, the first layer may be positioned closer to the razor blade than the second layer, and the hard coating may be positioned closer to the razor blade than the first layer.

[0066] In some embodiments, the first layer may be provided directly on the razor blade. In this case, the razor blade does not need to include the hard coating.

[0067] Alternatively, in some embodiments, the hard coating may be provided directly on the razor blade. In particular, hard coatings containing a metal that is particularly chromium, or consisting of a metal that is essentially particularly chromium, or consisting of a metal that is particularly chromium, may be placed directly on the razor blade.

[0068] Some hard coatings, particularly ceramic hard coatings, can exhibit better adhesion to the razor blade when the intermediate layer bonds the hard coating to the razor blade. Therefore, in some embodiments, the intermediate layer may be provided on the razor blade, and the hard coating may be provided on the intermediate layer. In some embodiments, the intermediate layer includes titanium and / or niobium, more specifically titanium, in particular metallic titanium.

[0069] Figure 1 shows the tip edge 100 of a first exemplary razor blade 10 according to a first embodiment. A first layer 102 containing titanium is provided on the tip edge 100. A second layer 104 containing parylene is provided on the first layer 102, specifically as the outermost layer provided on the razor blade 10.

[0070] Figure 2 shows the tip edge 200 of a second exemplary razor blade 20 according to the first embodiment. An intermediate layer 206 is provided on the tip edge 200, and a hard coating 208 is provided thereon. The hard coating 208 of the exemplary razor blade 20 may be ceramic in particular. A first layer 202 containing titanium is provided on the hard coating 208. A second layer 204 containing parylene is then provided on the first layer 202, particularly as the outermost layer.

[0071] Figure 3 shows the tip edge 300 of a third exemplary razor blade 30 according to the first embodiment. A hard coating 308 is directly provided on the tip edge 300. Some hard coatings, such as chromium, may not require an intermediate layer. A first layer 302 containing titanium is provided on the hard coating 300. A first sub-layer 304a containing parylene-C is provided on the first layer 302, and a second sub-layer 304b containing parylene-N is provided on top of that.

[0072] As will be described in more detail below, the first and second layers can be applied by thin-film deposition techniques. In particular, the first layer may be deposited by physical vapor deposition. Furthermore, the second layer may be deposited by chemical vapor deposition. As a result, the first and second layers can be applied to a relatively small tip edge. In particular, the first and second layers can be applied to a smaller tip edge compared to conventional PTFE coatings prepared by spraying. By reducing the tip edge, the cutting force required during the shaving operation can be reduced. Therefore, in some embodiments, the cross section of the tip edge may have a substantially symmetrical tapered shape terminating at the cutting edge, the cross section may have a central longitudinal axis starting from the cutting edge, and the tip edge may have a thickness of 1.5 μm to 2.4 μm measured at a distance of 5 μm from the cutting edge along the central longitudinal axis. In some embodiments, the edge of the blade has a thickness of approximately 4.6 μm to approximately 6.8 μm, particularly approximately 4.62 to approximately 6.74 μm, measured at a distance of approximately 20 μm from the cutting edge along the central longitudinal axis. In some embodiments, the edge of the blade has a thickness of approximately 10.3 μm to approximately 14.4 μm, particularly approximately 10.32 to approximately 14.35 μm, measured at a distance of approximately 50 μm from the cutting edge along the central longitudinal axis. In some embodiments, the edge of the blade has a thickness of approximately 19.8 μm to approximately 27.6 μm, particularly approximately 19.82 to approximately 27.52 μm, measured at a distance of approximately 100 μm from the cutting edge along the central longitudinal axis.

[0073] The razor blade described above can be manufactured by any preferred means. More specifically, the preparation and polishing of the blade base material can be carried out by any preferred means, for example, as disclosed in U.S. Patent Application Publication 2017 / 136641(A1), which is incorporated by reference in whole.

[0074] In some embodiments, the second layer may contain, not particularly contain, or substantially contain less than 1% by weight, more specifically less than 0.1% by weight, of polytetrafluoroethylene (PTFE) or any other perfluoroalkyl or polyfluoroalkyl substance (PFAS). As described above, the second layer containing parylene can be used to replace a lubricating coating containing PTFE (or any other PFAS). Furthermore, as described above, the first and second layers can be applied by thin-film deposition techniques, in contrast to PTFE coatings that require a spraying process. Thin-film deposition techniques can enable the deposition of a more uniform layer compared to spraying. Furthermore, thin-film deposition techniques can enable the deposition of a layer with fewer defects compared to spraying. Therefore, in some embodiments, the second layer may not contain pores, in particular pores having a diameter of about 5 nm to about 200 nm.

[0075] In a second aspect, the disclosure relates to a razor cartridge comprising at least one razor blade as described above. As described above, the lubricating coating provided by the second layer may be particularly beneficial for a razor blade for a razor cartridge.

[0076] In a third aspect, the disclosure relates to a method for coating a razor blade, the method comprising coating the razor blade with a first layer comprising titanium, more specifically by physical vapor deposition, and coating the razor blade with a second layer comprising parylene, more specifically by chemical vapor deposition.

[0077] In some embodiments, coating the razor blade with titanium may be performed before coating the razor blade with parylene. Thus, parylene may be deposited on the titanium, thereby improving the adhesion of parylene to the razor blade.

[0078] In some embodiments, coating the razor blade with a first layer containing titanium may be performed by sputtering. In some embodiments, coating the razor blade with a first layer containing titanium can be performed by, in particular, direct current (DC) sputtering, radio frequency (RF) sputtering, closed-field unbalanced magnetron sputtering (CFUMS), ion beam sputtering, cathode arc deposition, and high-power impulse magnetron sputtering (HiPIMS), using a sintered titanium target in an Ar atmosphere.

[0079] Examples of CVD techniques include low-pressure CVD (LPCVD), atmospheric-pressure CVD (APCVD), atomic layer deposition (ALD), and metalorganic CVD (MOCVD) using precursors. In some embodiments, coating a razor blade with parylene by chemical vapor deposition may include the steps of sublimating a parylene precursor dimer, thermally decomposing the sublimated parylene precursor dimer to obtain parylene precursor monomers, and depositing the parylene precursor monomers onto the razor blade so that the parylene precursor monomers polymerize. The parylene precursor monomers may polymerize on the razor blade during or after deposition. Polymerization of the parylene precursor monomers can result in the formation of a parylene layer. If the second layer includes a first sublayer containing a first parylene such as parylene-C and a second sublayer containing a second parylene such as parylene-N, the above steps of chemical vapor deposition (sublimation step, pyrolysis step, and deposition step) can be performed individually for each sublayer.

[0080] In some embodiments, the sublimation of the parylene precursor dimer may be carried out at a temperature of about 130°C to about 190°C, more specifically about 150°C to about 180°C, and / or at a pressure of about 0.5 Torr to about 2 Torr, more specifically about 0.8 Torr to about 1.2 Torr.

[0081] In some embodiments, the thermal decomposition of the sublimated parylene precursor dimer may be carried out at a temperature of about 400°C to about 800°C, more specifically about 500°C to about 700°C, and / or at a pressure of about 0.2 Torr to about 1 Torr, more specifically about 0.4 Torr to about 0.6 Torr.

[0082] In some embodiments, the deposition of parylene precursor monomers may be carried out at a temperature of about 10°C to about 50°C, more specifically about 17°C to about 28°C, and / or at a pressure of about 0.01 Torr to about 0.5 Torr, more specifically about 0.05 Torr to about 0.2 Torr.

[0083] In some embodiments, the method may include a film growth step after the deposition of parylene precursor monomers, the film growth step being carried out at a temperature of about 50°C to about 100°C, more specifically about 60°C to about 80°C, and / or at a pressure of about 0.0001 Torr to about 0.05 Torr, more specifically about 0.0005 Torr to about 0.002 Torr. The film growth step can better polymerize the parylene precursor monomers deposited on the razor blade.

[0084] In some embodiments, the method for coating the razor blade may further include an annealing step. In this case, the razor blade may be annealed in an inert gas atmosphere at a temperature of about 300°C to about 400°C, more specifically about 330°C to about 370°C, especially if this is done after the deposition of parylene or after the film growth step. In some embodiments, the razor blade may be annealed for a duration of about 10 seconds to about 20 minutes, more specifically about 1 minute to about 5 minutes. Annealing for more than 20 minutes may reduce the hardness and / or corrosion resistance of the razor blade. In some embodiments, the razor blade may be annealed in an inert atmosphere, more specifically a nitrogen atmosphere or an argon atmosphere. The annealing step can make it possible to reduce the cutting force required during the shaving operation. Although not bound by theory, it is thought that the annealing step can increase the crystallinity of parylene, which can result in an increase in the strength of parylene, thereby reducing the required cutting force. Furthermore, the softening of parylene during the annealing process can further enhance the uniformity of the second layer. The annealing process can also reduce surface defects in the second layer, such as its porosity.

[0085] As described above, a hard coating may be provided on the razor blade. Therefore, the razor blade may be coated with a hard coating, particularly before being coated with the first layer. The razor blade may be coated with a hard coating using, for example, a chemical vapor deposition process or a physical vapor deposition process. Exemplary hard coating deposition processes are described in U.S. Patent Application Publication 2018 / 215056(A1) and U.S. Patent No. 10,442,098(B2), both of which are incorporated herein by reference in their entirety.

[0086] As described above, an intermediate layer may be provided on the razor blade. Therefore, the razor blade may be coated with an intermediate layer, particularly before being coated with a hard coating. The razor blade may be coated with an intermediate layer in the same way as the razor blade is coated with a first layer. Therefore, in some embodiments, coating the razor blade with an intermediate layer, particularly an intermediate layer containing titanium, can be done by sputtering. In some embodiments, coating the razor blade with an intermediate layer can be done by direct current (DC) sputtering, radio frequency (RF) sputtering, closed-field unbalanced magnetron sputtering (CFUMS), ion beam sputtering, cathode arc deposition, and high-power impulse magnetron sputtering (HiPIMS), particularly using a sintered metal target, particularly a sintered titanium target, in an Ar atmosphere.

[0087] Experiment section Sample preparation Five different sample lots (Sample Lots 1, 2, 3, 4, and 5) were prepared according to the first embodiment. Furthermore, two comparative sample lots, 1 and 2, unrelated to the first embodiment, were also prepared.

[0088] 1. First sample lot (Titanium + Parylene-C) A first sample lot according to the first embodiment comprises a first layer containing titanium and a second layer containing parylene-C. The first sample lot was prepared by the following procedure.

[0089] Ten stainless steel razor blades were stacked on a blade carrier in a rotating jig of the deposition chamber. The deposition chamber was equipped with a titanium target and a TiB2 target. If a chromium layer was deposited as a capping layer, for example, the deposition chamber was also equipped with a chromium target.

[0090] Prior to the deposition of the intermediate layer, a series of preparatory steps were performed, including sputter etching. The deposition chamber was evacuated to a base pressure of 10⁻⁵ Torr using a vacuum. Next, Ar gas was introduced into the chamber from an Ar gas source, and the pressure was increased to 8 mTorr (8.10 to 3 Torr). The loaded bayonet was rotated at a constant speed of 6 rpm in a rotating fixture using a motor, and all targets, especially the Ti target and TiB2 target, were operated under a DC current control of 0.2 Amps. A DC voltage of 200–600 V was applied to the stainless steel blade for 4 minutes. The sputter etching process helps to remove impurities from the blade substrate and target by impacting them with argon ions.

[0091] After that, the coating process itself was carried out.

[0092] In the first series of steps for forming the intermediate layer, the chamber pressure was adjusted to 3 mTorr. While applying a DC voltage of 0 to 50 V to the rotating blade, the Ti target and TiB2 target(s) were operated under DC current control of 3 Amps and 0.2 Amps, respectively. By adjusting the deposition time, a Ti layer of 20 to 40 nm was deposited on the edge of the blade sample.

[0093] In the second series of steps, a TiB2 hard coating was deposited after the deposition of the Ti interlayer. The hard coating was also deposited at a pressure of 3 mTorr. The Ti target, Cr target (if present), and TiB2 target were operated simultaneously, with the current to the Cr and Ti targets set to 0.2 Amps and the current to the TiB2 target set to 3 Amps. The current to the Ti and Cr targets was used to prevent elemental deposition on the targets. A DC bias voltage of 150-350 V was applied to the rotating blade. The deposition time was adjusted to deposit a 150-300 nm TiB2 layer on the Ti layer.

[0094] In the third series of steps, the first layer was deposited on the hard coating. The first layer was also deposited under a pressure of 3 mTorr. The titanium target was operated under a DC current control of 3 to 10 Amps while a DC voltage of 0 to 50 V was applied to the rotating blade. By adjusting the deposition time, a titanium layer with a thickness of 20 to 40 nm was deposited on the razor blade.

[0095] In a fourth series of steps for forming the second layer, the rotating jig was moved to a second deposition chamber equipped with a vaporizer, a pyrolysis chamber, a deposition chamber, a cold trap, and a mechanical vacuum pump. The second chamber was then evacuated to a base pressure of 1 Torr. The parylene-C precursor dimer was evaporated at a temperature of 175°C. The pressure in the chamber was then reduced to 0.5 Torr, and the parylene-C precursor dimer was pyrolyzed at a temperature of 680°C to form parylene-C precursor monomers. The formed parylene-C precursor monomers were then deposited at a temperature of 25°C and a pressure of 0.1 Torr. The temperature was then raised to 70°C at a pressure of 0.001 Torr.

[0096] In a fifth series of steps for annealing the razor blade, the second chamber was filled with argon at atmospheric pressure and heated to a temperature of 350°C for 10 minutes to anneal the razor blade. After cooling to room temperature, the finished razor blade according to the first embodiment was removed from the second chamber.

[0097] 2. Second sample lot (Titanium + Parylene-N) A second sample lot was prepared in the same manner as the first sample lot, except that in the fourth series of steps, a parylene-N precursor dimer was used in contrast to the parylene-C precursor dimer.

[0098] 3. Third sample lot (Titanium + Parylene-C + Parylene-N) A third sample lot was prepared in the same manner as the first sample lot, except that after the deposition of parylene-C, the fourth series of steps was repeated using a parylene-N precursor dimer to deposit a first sublayer containing parylene-C and a second sublayer containing parylene-N.

[0099] 4. Fourth sample lot (Titanium + Parylene-F) The fourth sample lot was prepared in the same manner as the first sample lot, except that in the fourth series of steps, a parylene-F precursor dimer was used instead of a parylene-C precursor dimer.

[0100] 5. Fifth sample lot (Titanium + Parylene-C + Parylene-N (unannealed)) The fifth sample lot was prepared by coating the razor blades in the same way as the third sample lot, but the fifth series of steps was not performed. Therefore, the fifth sample lot was not annealed.

[0101] 6. Sixth sample lot (Titanium + Parylene-N (unannealed)) The sixth sample lot was prepared by coating the razor blades in the same way as the second sample lot, but the fifth series of steps was omitted. Therefore, the sixth sample lot was not annealed.

[0102] 7. First comparative sample lot (chromium + parylene-C + parylene-N) The first comparative sample lot was prepared in the same way as the first sample lot, but in the third series of steps, instead of using titanium, the razor blade was coated with chromium.

[0103] 8. Second comparative sample lot (chromium) A second comparative sample lot was prepared. The second comparative sample lot underwent the first and second series of steps. Furthermore, the second comparative sample lot underwent the third series of steps, but was coated with chromium instead of titanium. The second comparative sample lot was not subjected to the fourth or fifth series of steps.

[0104] 9. Third comparative sample lot (chromium + parylene-N (unannealed)) The third comparative sample lot was prepared in the same manner as the sixth sample lot, but instead of using titanium in the third series of steps, the razor blade was coated with chromium.

[0105] Cutting force experiment The cutting force was measured for the first, second, third, fourth, and fifth sample lots, as well as the first comparative sample lot.

[0106] Ten blades per sample lot were each used to make 10 consecutive cuts on a moving wool felt. These blades were individually placed in holders connected to load cells. The load cells were used to measure the load on the blades during the cutting operation.

[0107] In the following, Figures 4 to 6 show the test results as follows: The "Y" axis indicates the required cutting force in "kg", and the "X" axis indicates the number of cuts. The first sample lot is indicated by the letter "A", the second sample lot by the letter "B", the third sample lot by the letter "D", the fourth sample lot by the letter "C", and the fifth sample lot by the letter "E". The first comparative sample lot is indicated by the letter "F". The sixth sample lot is indicated by the letter "H". The third comparative sample lot is indicated by the letter "I".

[0108] Figure 4 shows a comparison of the cutting force between the third sample lot and the first comparative sample lot. As shown in Figure 4, the razor blade with the first layer containing titanium has significantly less cutting force compared to the razor blade with the first layer containing chromium.

[0109] Figure 5 shows a comparison of the cutting forces of the first, second, third, and fourth sample lots. As shown in Figure 5, the razor blade with a second layer containing parylene-N (second sample lot) has a small cutting force on the first cut, but the cutting force required to surpass that of the parylene-C coated blade (first sample lot) increases with the number of cuts. On the other hand, the parylene-C coated blade (first sample lot) requires a greater cutting force on the first use. The razor blade coated with a first sublayer containing parylene-C and a second sublayer containing parylene-N (third sample lot) performs better than the first and second sample lots in all 10 cuts. The razor blade with a second layer containing parylene-F (fourth sample lot) consistently shows a larger cutting force compared to the other parylenes.

[0110] Figure 6 shows a comparison of the cutting force of the third and fifth sample lots. As shown in Figure 6, the annealed razor blade has significantly less cutting force compared to the unannealed razor blade.

[0111] Figure 7 shows a comparison of the frictional force (Y-axis) in grams between the second comparison sample lot "G" and the second sample lot "B". The X-axis shows the distance traveled on the paper in millimeters. In this test, the felt was replaced with cellulose paper. One razor blade from the second sample lot was placed parallel to the paper, and the paper was moved, with the frictional force measured over the distance traveled. The test was then repeated for the second comparison sample lot. As shown in Figure 7, the frictional force of the second sample lot is significantly lower than that of the second comparison sample lot.

[0112] Figure 8 shows a comparison of the cutting force of the sixth sample lot and the third comparative sample lot. As shown in Figure 8, the razor blade with the first layer containing titanium has significantly less cutting force compared to the razor blade with the first layer containing chromium.

[0113] manner 1. A razor blade comprising a first layer containing titanium and a second layer containing parylene.

[0114] 2. The razor blade according to embodiment 1, wherein the first layer contains titanium as metallic titanium.

[0115] 3. The razor blade according to embodiment 1 or 2, wherein parylene is selected from the group consisting of parylene-N, parylene-C, parylene-F, and combinations thereof, and in particular, parylene is selected from parylene-N and / or parylene-C.

[0116] 4. A razor blade according to any one of embodiments 1 to 3, wherein the razor blade has a tip edge, and the first layer and the second layer are provided on the tip edge.

[0117] 5. A razor blade according to any one of embodiments 1 to 4, wherein the razor blade is configured to be placed inside a razor cartridge.

[0118] 6. A razor blade according to any one of embodiments 1 to 5, wherein the first layer has a thickness of approximately 5 nm to approximately 70 nm, more specifically approximately 10 nm to approximately 60 nm, and particularly approximately 20 nm to approximately 50 nm.

[0119] 7. A razor blade according to any one of embodiments 1 to 6, wherein the second layer has a thickness of approximately 0.005 μm to approximately 5 μm, more specifically approximately 0.02 μm to approximately 2 μm, and particularly approximately 0.1 μm to approximately 1 μm.

[0120] 8. A razor blade according to any one of embodiments 1 to 7, wherein the second layer does not contain pores, and in particular does not contain pores having a diameter of about 5 nm to about 200 nm.

[0121] 9. A razor blade according to any one of embodiments 1 to 8, wherein the second layer contains less than 1% by weight, more specifically less than 0.1% by weight of polytetrafluoroethylene, and is particularly free of or substantially free of polytetrafluoroethylene.

[0122] 10. A razor blade according to any one of embodiments 1 to 9, further comprising a hard coating, more specifically, the hard coating comprising a ceramic, metal, and / or non-metallic coating.

[0123] 11. The razor blade according to embodiment 10, wherein the ceramic comprises borides and / or carbides, particularly titanium diboride or titanium, boron and carbon.

[0124] 12. The razor blade according to embodiment 10 or 11, wherein the hard-coated metal contains chromium.

[0125] 13. A razor blade according to any one embodiment of embodiments 10 to 12, wherein the non-metallic coating includes diamond-like carbon.

[0126] 14. A razor blade according to any one of embodiments 1 to 13, wherein the first layer is disposed between the hard coating and the second layer.

[0127] 15. The first layer is provided directly on the razor blade. Alternatively, the hard coating may be applied directly to the razor blade. Alternatively, the razor blade according to any one of embodiments 1 to 14, wherein the intermediate layer is provided on the razor blade, and the hard coating is provided on the intermediate layer, and more specifically, the intermediate layer contains niobium or titanium, and in particular, the intermediate layer contains metallic titanium.

[0128] 16. A razor blade according to any of embodiments 1 to 15, comprising a metal, particularly stainless steel, or essentially consisting of a metal, particularly stainless steel.

[0129] 17. A razor blade according to any one embodiment of embodiments 4 to 16, wherein the cross-section of the tip edge has a substantially symmetrical tapered shape terminating at the cutting edge, the cross-section has a central longitudinal axis starting from the cutting edge, and the tip edge has a thickness of 1.5 μm to 2.4 μm measured at a distance of 5 μm from the cutting edge along the central longitudinal axis.

[0130] 18. A razor cartridge comprising at least one razor blade as described in any of embodiments 1 to 17.

[0131] 19. A method for coating a razor blade, the method being: - The razor blade is coated with a first layer containing titanium, more specifically by physical vapor deposition, A method comprising coating a razor blade with a second layer containing parylene, more specifically by chemical vapor deposition.

[0132] 20. The method according to embodiment 19, wherein the razor blade is coated with titanium before the razor blade is coated with parylene.

[0133] 21. The method according to embodiment 19 or 20, wherein the razor blade is coated with a first layer containing titanium by sputtering.

[0134] 22. Coating razor blades with parylene by chemical vapor deposition is, - Sublimation of the parylene precursor dimer, -In order to obtain the monomer of the parylene precursor, the sublimated parylene precursor dimer is thermally decomposed, - The method according to any one embodiment of embodiments 19 to 21, comprising depositing a monomer of a parylene precursor onto a razor blade.

[0135] 23. The method according to any embodiment 22, wherein the sublimation of the parylene precursor dimer is carried out at a temperature of about 130°C to about 190°C, more specifically at a temperature of about 150°C to about 180°C, and / or at a pressure of about 0.5 Torr to about 2 Torr, more specifically at a pressure of about 0.8 Torr to about 1.2 Torr.

[0136] 24. The method according to embodiment 22 or 23, wherein the thermal decomposition of the sublimated parylene precursor dimer is carried out at a temperature of about 400°C to about 800°C, more specifically at a temperature of about 500°C to about 700°C, and / or at a pressure of about 0.2 Torr to about 1 Torr, more specifically at a pressure of about 0.4 Torr to about 0.6 Torr.

[0137] 25. The method according to any one embodiment of embodiments 22 to 24, wherein the deposition of parylene precursor monomers is carried out at a temperature of about 10°C to about 50°C, more specifically at a temperature of about 17°C to about 28°C, and / or at a pressure of about 0.01 Torr to about 0.5 Torr, more specifically at a pressure of about 0.05 Torr to about 0.2 Torr.

[0138] 26. The method according to any one embodiment of embodiments 19 to 25, further comprising an annealing step, wherein the razor blade is annealed in an inert gas atmosphere at a temperature of about 300°C to about 400°C, more specifically at a temperature of about 330°C to about 370°C, particularly after the deposition of parylene.

[0139] 27. The method according to embodiment 26, wherein the razor blade is annealed for a duration of approximately 10 seconds to approximately 20 minutes, more specifically for a duration of approximately 1 minute to approximately 5 minutes.

Claims

1. A razor blade comprising a first layer containing titanium and a second layer containing parylene.

2. The razor blade according to claim 1, wherein the first layer comprises titanium as metallic titanium.

3. The parylene is selected from the group consisting of parylene-N, parylene-C, parylene-F, and combinations thereof, and in particular, the parylene is selected from parylene-N and / or parylene-C, as described in claim 1 or 2.

4. The razor blade according to any one of claims 1 to 3, wherein the razor blade has a tip edge, and the first layer and the second layer are provided on the tip edge.

5. The razor blade according to any one of claims 1 to 4, wherein the razor blade is configured to be placed inside a razor cartridge.

6. The razor blade according to any one of claims 1 to 5, wherein the first layer has a thickness of about 5 nm to about 70 nm, more specifically about 10 nm to about 60 nm, and particularly about 20 nm to about 50 nm.

7. The razor blade according to any one of claims 1 to 6, wherein the second layer has a thickness of about 0.005 μm to about 5 μm, more specifically about 0.02 μm to about 2 μm, and particularly about 0.1 μm to about 1 μm.

8. The razor blade according to any one of claims 1 to 7, wherein the second layer does not contain pores, and in particular does not contain pores having a diameter of about 5 nm to about 200 nm.

9. The razor blade according to any one of claims 1 to 8, wherein the second layer contains less than 1% by weight, more specifically less than 0.1% by weight of polytetrafluoroethylene, and is particularly free of or substantially free of polytetrafluoroethylene.

10. The razor blade according to any one of claims 1 to 9, further comprising a hard coating, more specifically, the hard coating comprising a ceramic, metal, and / or non-metallic coating.

11. The razor blade according to claim 10, wherein the first layer is disposed between the hard coating and the second layer.

12. The first layer is provided directly on the razor blade, Alternatively, the hard coating may be provided directly on the razor blade. Alternatively, the razor blade according to any one of claims 1 to 11, wherein the intermediate layer is provided on the razor blade, and the hard coating is provided on the intermediate layer, and more specifically, the intermediate layer contains niobium or titanium, and in particular, the intermediate layer contains metallic titanium.

13. The razor blade according to any one of claims 1 to 12, wherein the razor blade includes a metal, particularly stainless steel, or is essentially made of a metal, particularly stainless steel, or is made of a metal, particularly stainless steel.

14. A razor cartridge comprising at least one razor blade as described in any one of claims 1 to 13.

15. A method for coating a razor blade, wherein the method is The first layer containing titanium, more specifically by physical vapor deposition, coats the razor blade, A method comprising coating the razor blade with a second layer containing parylene, more specifically by chemical vapor deposition.

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