Thinning of razor blade coatings

Abstract

The invention relates to a method of thinning a coating applied on a razor blade. The method comprises providing a thinning material having a Shore OO hardness in a range of 10-100, more specifically 20-70; contacting the thinning material with an edge of the razor blade, and moving the thinning material relative to the edge of the razor blade such that a shear force is applied on the edge of the razor blade thereby removing at least a portion of the coating applied on the edge of the razor blade.

Claims

1. A method of thinning a lubricating coating applied on a razor blade, the method comprising: providing a thinning material having a Shore OO hardness in a range of 10-100, contacting the thinning material with an edge of the razor blade, and moving the thinning material relative to the edge of the razor blade so that a shear force is applied on the edge of the razor blade thereby removing at least a portion of the lubricating coating applied on the edge of the razor blade.

2. The method according to claim 1, wherein the thinning material has a Shore OO hardness in a range of 20-70.

3. The method according to claim 1, wherein during the step of moving the thinning material relative to the edge of the razor blade, the razor blade is maintained at a temperature in a range of 15 to 330° C.

4. The method according to claim 1, wherein during the step of moving the thinning material relative to the edge of the razor blade, the razor blade is maintained at a temperature in a range of 15−40° C.

5. The method according to claim 1, wherein the thinning material is polystyrene foam.

6. The method according to claim 1, wherein the thinning material is a mechanical tool selected from the group consisting of a brush-like tool, bristles and a rotary tool.

7. The method according to claim 1, wherein the step of moving the thinning material relative to the edge of the razor blade includes moving the thinning material in a first direction that is parallel to the edge of the razor blade.

8. The method according to claim 7, wherein the step of moving the thinning material relative to the edge of the razor blade further includes moving the razor blade and the thinning material relative to each other at a speed in a range of 0.003-0.3 m/s.

9. The method according to claim 1, wherein the step of contacting the thinning material with an edge of the razor blade comprises contacting the thinning material with respective edges of a plurality of razor blades.

10. The method according to claim 1, wherein the thickness of the thinning material is in a range of 1-50 mm.

11. The method according to claim 1, wherein contacting the thinning material with an edge of the razor blade comprises inserting the edge of the razor blade at least partially into the thinning material.

12. The method according to claim 11, wherein the blade edge is inserted into the thinning material up to 2 mm.

13. The method according to claim 11, wherein during the step of moving the thinning material relative to the edge of the razor blade, the blade edge and the thinning material are arranged to have an angle of between 0.5 degrees and 90 degrees relative to each other.

14. The method according to claim 1, wherein moving the thinning material relative to the edge of the razor blade comprises a back-and-forth motion, a circular motion or a swiveling motion.

15. The method according to claim 1, wherein contacting the thinning material with the edge of the razor blade comprises contacting the thinning material with at least one facet of the blade edge.

16. The method according to claim 1, wherein the lubricating coating applied on the razor blade is polyfluorocarbon.

17. The method according to claim 1, wherein the lubricating coating applied on the razor blade is polytetrafluoroethylene.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure may be more completely understood in consideration of the following detailed description of non-limiting aspects of the disclosure in connection with the accompanying drawings, in which:

(2) FIG. 1 is a schematic view of a razor blade and a thinning material;

(3) FIG. 2A is an image showing an uncoated razor blade before and after performing the silicon oil method;

(4) FIG. 2B is an image showing a razor blade having a PTFE coating that has not been thinned, before and after performing the silicon oil method;

(5) FIG. 2C is an image showing a razor blade having a PTFE coating that has been thinned using the disclosed method, before and after performing the silicon oil method;

(6) FIG. 3A is an image showing an SEM micrograph at 5000× magnification on a razor blade having a PTFE coating that has not been thinned;

(7) FIG. 3B is an image showing an SEM micrograph at 5000× magnification on a razor blade having a PTFE coating that has been thinned using the disclosed method;

(8) FIG. 4 is a graph showing a comparison of the friction force of a razor blade that has a PTFE coating that has not been thinned and a friction force of a PTFE coating that has been thinned according to the disclosed method; and

(9) FIG. 5 is a graph showing a comparison of the cutting force of an untreated razor blade and a treated razor blade.

(10) While aspects of the disclosure are amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the figures and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the disclosure to the particular example described. On the contrary, the intention of this disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.

DETAILED DESCRIPTION

(11) As used in this disclosure and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this disclosure and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.

(12) The following detailed description should be read with reference to the figures. The detailed description and the figures, which are not necessarily to scale, depict illustrative aspects and are not intended to limit the scope of the invention. The illustrative aspects depicted are intended only as exemplary.

(13) FIG. 1 is a schematic view of a razor blade 10 having a blade edge 12 and a lubricating coating. The razor blade 10 may have a top surface 10a and an opposing bottom surface (not shown). The deposition of the lubricating coating on blade edge 12 may be performed by chemical vapor deposition, laser deposition, sputtering deposition, or nebulization process. Alternatively, the deposition may be performed by dipping, brushing, or spraying. Other ways of applying a lubricating coating on a blade edge may also be foreseen.

(14) Aspects of the present disclosure provide for a process for thinning the already formed lubricating coatings. In some examples, the lubricating coating applied on the razor blade 10 may be polyfluorocarbon, more specifically polytetrafluoroethylene (PTFE). In some examples, the methods as herein disclosed may be performed on the razor blade 10 when the razor blade 10 is maintained at a temperature in the range 15-330° C.

(15) In examples, the blade edge 12 may be inserted into a “soft” thinning material 20. The thinning material 20 may have a Shore OO hardness in a range of 10-100, more specifically 20-70. In some examples, the methods as herein disclosed comprise contacting the thinning material 20 with an edge 12 of the razor blade 10, and moving the thinning material 20 relative to the edge 12 of the razor blade 10 such that a shear force is applied on the edge 12 of the razor blade 10. This results in removing at least a portion of the coating applied on the edge 12 of the razor blade 10.

(16) In some examples, the thinning material 20 may be in the form of a monoblock component. Examples of monoblock components may comprise rubber, cork, felt, cotton textile, soft polymer or a foamy polymer, for example, polystyrene foam (chemical formula (C8H8)n). In some examples, the thinning material 20 may be formed as a rectangular prism. In some examples, the thinning material 20 may have a thickness within a range of 1-50 mm. In alternatives, the thinning material 20 may have any other shape or configuration.

(17) In some embodiments, the thinning material 20 may be configured as a mechanical tool, such as a brush-like tool or a bristle or any other two-component tool, such as a rotary tool comprising a shaft as a base and a contacting surface made of felt, flannel, cotton, leather, composite or other material typically used for polishing, buffing, grinding or other material processing. Combinations of the mechanical tool with the herein disclosed monoblock components may also be foreseen.

(18) In some examples, contacting the thinning material 20 with an edge 12 of the razor blade 10 may comprise contacting the thinning material 20 with respective edges 12 of a plurality of razor blades 10 and the movement of the thinning material relative to the respective edges 12 of the plurality of razor blades 10 may be accomplished.

(19) In some examples, the methods comprise contacting the thinning material 20 with the edge 12 of the razor blade 10 by inserting the edge 12 of the razor blade 10 at least partially into the thinning material 20. In still more examples in which the razor blade 10 may be inserted into the thinning material 20, the blade edge 12 may itself cut the thinning material 20, thus wedging adjacent facets of the blade edge 12 of the razor blade 10 into the thinning material 20. In these examples, the razor blade 10 may be configured to be inserted into the thinning material up to 2 mm. In examples, the blade 10 may be configured to be inserted into the thinning material 20 from at least 5 μm, to substantially cover the blade edge. Thereafter, the blade edge 12 may be sheared with the thinning material 20. Alternatively, the thinning material 20 may be positioned to simply contact the adjacent facets, and thereafter, the blade edge 12 may be sheared with the thinning material 20. In some examples, contacting the thinning material 20 with an edge 12 of the razor blade 10 may comprise contacting the thinning material 20 with at least one facet of the blade edge 12.

(20) In some examples, moving the thinning material 20 relative to the edge 12 of the razor blade 10 may include moving the thinning material 20 in a first direction D1 that may be parallel to the blade edge 12, as shown in FIG. 1. During this movement of the thinning material 20 in the first direction D1, the razor blade 10 may be stationary such that only the thinning material 20 moves. In alternatives, the thinning material 20 may be stationary and only the razor blade 10 may be moved along the first direction D1. In still more examples, the thinning material 20 and the razor blade 10 may be moved relative to each other. In some examples, the thinning material 20 and/or the blade edge 12 may move only in a single direction. In others, the thinning material 20 and/or the blade edge 12 may move in a first direction D1 and then in a second direction D2 that is opposite from the first direction D1, e.g., in a back-and-forth motion. In others, the thinning material 20 may be moved relative to the blade edge 12 in a circular or swiveling motion. In other examples, the thinning material 20 and/or the blade edge 12 may move relative to each other in non-parallel directions. The thinning material 20 and the blade edge 12 may move with respect to each other at an angle between 0.5° and 90°. In some examples, moving the thinning material 20 relative to the edge 12 of the razor blade 10 may comprise arranging the blade edge 12 and the thinning material 20 to be angled relative to each other.

(21) Throughout the present description and claims, the term “shearing away” is intended to mean applying a shear stress/force to the lubricating coating on the razor blade. Shear stress/force is the application of a frictional force parallel to co-planar cross-sectional areas of the coating. In a manufacturing setting, the thinning approach allows for an in line process application without transferring the finished blade(s) to a separate manufacturing station.

(22) In some examples, the thinning process may be performed until the thickness of the coating is approximately 1-50 nm. In some examples, the thinning process may be repeated until the thickness of the coating applied on the edge 12 of the razor blade 10 is in a range of 1-50 nm. In some examples, the force applied by the thinning material may be within a range of 0.1-100N. The application of a steady force throughout the thinning process allows for a gentle thinning process that avoids or at least reduces premature degradation of the blade 10. The value/magnitude of the force applied on the blade edge 12 affects the amount of coating that is removed. In some examples, the razor blade 10 and the thinning material 20 may be moved relative to each other at a speed within a range of 0.003-0.3 m/s.

(23) Thinning processes as herein disclosed allows for the removal of any excess coating, leaving only a thin layer of the coating which is well adhered to the edge 12 of the razor blade 10. In some examples, a razor blade 10 may be obtained by the herein disclosed processes, where the edge 12 of the razor blade 10 may have a lubricating coating having thickness in a range from 1-50 nm. Furthermore, the thinning process as herein disclosed is a soft thinning process thereby thinning the lubricating coating such that it is not visible under an optical microscope.

(24) This is shown in FIGS. 2A-2C. Usually, a silicon oil method is used to confirm the presence of PTFE coating. FIG. 2A shows images of an uncoated razor blade before and after performing the silicon oil method. FIG. 2B shows images of a razor blade with a PTFE coating where the coating has not been thinned, i.e. an untreated blade, before and after performing the silicon oil method. FIG. 2C shows images of a razor blade (with a PTFE coating where the coating has been thinned using the disclosed thinning methods, i.e. a treated razor blade, before and after performing the silicon oil method. In some examples, as shown in FIG. 2A, silicon oil fully wets an uncoated razor blade, whereas as shown in FIG. 2B, silicon oil is repelled from a razor blade having an initial PTFE coating. As shown in FIG. 2C, silicon oil is repelled from a razor blade after thinning which is an indication of its presence even if it could not be observed under optical microscope.

(25) A comparison of the images of the uncoated razor blade of FIG. 2A and the treated razor blade shown in FIG. 2C shows that the surfaces appear similar. However, the image of the untreated razor blade shown in FIG. 2B is different and shows the surface having a blotchy appearance. These blotches show the excess PTFE material on the razor blade. Additionally, as can be seen in comparing FIGS. 2A and 2C, the blade edge has not been damaged by the mechanical thinning process, as there is no indication of blade edge damage after the removal of excess of PTFE using the described method.

(26) The examples of FIGS. 3A and 3B show images of a SEM micrograph at 5000× magnification on a razor blade having a PTFE coating. FIG. 3A shows the razor that has not been thinned, i.e. an untreated razor blade and FIG. 3B shows a razor blade having a PTFE coating that has been thinned, i.e. a treated razor blade. As can be seen in FIG. 3A, the untreated razor blade shows the excess PTFE as having an uneven and layered surface, whereas FIG. 3B shows the treated razor blade as having a more uniform surface. This substantially uniform surface avoids or at least reduces the discomfort to a user when they use the razor blade.

(27) FIG. 4 is a graph showing the comparison of the friction force of an untreated razor blade and a treated razor blade. As can be seen, as the distance increases, the frictional force (gr) of the untreated razor blade gets higher than the treated razor blade as measured by a Friction Test.

(28) In the Friction Test, the friction force between the blade edge and paper is measured when one facet of the blade edge slides over a paper ribbon. The blade-sample is placed on an appropriate blade mounting base such that only one facet of the razor blade is in contact with and is parallel to the paper. During the measurement, while the paper is moving with a specific speed and for a determined distance, friction forces are developed which are detected by a load cell and recorded through a program. The obtained data can thus be plotted on a graph of Friction force (gr) vs distance (mm) as that shown in the example of FIG. 4.

(29) FIG. 5 is a graph showing the comparison of the cutting force of an untreated razor blade and a treated razor blade measured by a cutting force test. The cutting force test involves repeating cutting action of the razor blade on a moving felt, using a load cell for measuring the load on the razor blade for a series of 10 cuts. The graph shows that the treated razor blade presents a lower cutting force at least for the initial cuts.

(30) Throughout the present description, including the claims, the term “comprising a” should be understood as being synonymous with “comprising at least one” unless otherwise stated. In addition, any range set forth in the description, including the claims should be understood as including its end value(s) unless otherwise stated. Specific values for described elements should be understood to be within accepted manufacturing or industry tolerances known to one of skill in the art, and any use of the terms “substantially” and/or “approximately” and/or “generally” should be understood to mean falling within such accepted tolerances.

(31) Although the present disclosure herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present disclosure.

(32) It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims.