JP2005528203A - Cutting edge coating method - Google Patents

Abstract

  The present invention provides a lubricating strip for use in a wet shaving system where the strip comprises a biodegradable polymer, preferably a biodegradable polymer that is surface eroded and non-bulk eroded.

Description

  The present invention relates to the manufacture of blades and other cutting instruments such as razor blades, knives and the like. More specifically, the present invention relates to a method for applying a coating to the cutting edge of the above-mentioned blade and cutting tool.

  This application is given the benefit of the essential subject matter disclosed in US Provisional Application No. 60 / 384,322, filed May 30, 2002 in the name of Warner Lambert, which is incorporated by reference. To do.

  Cutting tools such as knives, scalpels, and razor blades are generally made of metal, ceramic, glass or glassy material and have at least one substantially V-shaped cutting edge. In the case of a razor blade, the cutting edge typically has a radius less than about 1000 angstroms and a taper angle less than 30 degrees. When the shaving operation becomes intense, the blade edge can be damaged as a result. Therefore, one or more coatings may be applied to the cutting edge of the razor blade to increase the user's comfort and / or ease of shaving to increase the cutting edge hardness and / or corrosion resistance, and / or Obtaining other advantageous effects is a common practice.

  Examples of coating materials that have been used and / or proposed to coat cutting edges, particularly razor blade cutting edges, include polyethylene, halogenated polymers, telomers (low molecular weight polymers), etc. Is a thermoplastic material. See U.S. Pat. Nos. 3,224,900, 3,518,110, 3,658,742, 5,263,256 and 5,985,459 in this regard. These disclose various polymer coatings for the cutting edge of a razor blade and also disclose methods for applying the coating to the cutting edge. The contents of these patents are hereby incorporated by reference and are incorporated herein as an integral part of the disclosure of this application.

  One method of applying a thermoplastic coating material to the cutting edge of a razor blade is to spray a suspension of dispersed coating material onto the edge and then heat the blade in a non-oxidizing environment to create a polymer coating. Including melting and evenly spreading the material over the blade edge surface. Upon cooling of the razor, the coating material solidifies and remains attached to the cutting edge. This heating of the razor for melting is generally performed on the razor by, for example, infrared heating, induction heating, or resistance heating at about 200 ° C. to about 400 ° C. Examples of the coating method are disclosed in the aforementioned U.S. Pat. Nos. 3,224,900, 3,518,110, 3,658,742, 5,263,256 and 5,985,459. It is disclosed.

  Resistance heating and induction heating are associated with a considerable energy consumption and require a considerable amount of time to heat the blade to the temperature required to melt the polymer. Such a heating operation heats the entire blade body, including the blade carrier, and therefore requires a greater amount of heat than is required to melt only the polymer confined to the blade edges. Infrared heating is somewhat faster than resistance heating or induction heating (which takes about 60-90 minutes to heat a 12 inch blade laminate) but still takes a significant amount of time to heat the polymer particles to the melting temperature. It takes a considerable amount of time to cool the blade body sufficiently to solidify the molten polymer particles.

  In addition to the high energy consumption and processing time associated with the coating methods described above, the heating can adversely affect blade hardness.

  Microwave energy is conventionally used to apply polymer materials to various substrate surfaces. In this regard, see US Pat. Nos. 5,422,146, 5,804,801, and 5,879,756. The contents of these patents are hereby incorporated by reference and incorporated herein as an integral part of the present disclosure. However, it is believed that no microwave energy has been previously disclosed for melting the fusible coating material applied to the cutting edge of a razor blade or other cutting instrument.

  An object of the present invention is to improve the above-described prior art coating method by providing a coating containing a fusible polymer material on the cutting edge of a blade and melting (melting) the polymer using microwave energy as a heat source. Is to provide.

  In accordance with the present invention, a microwave energy heat source is applied to provide a coating comprising a fusible material to a cutting edge of a cutting instrument and to melt the fusible material into a substantially uniform coating that adheres to the cutting edge. The above and other objects are achieved by the method of the present invention comprising heating a fusible material using a slag.

  As a result of this coating method, the required amount of energy and the heating and cooling time required to dissolve and solidify the fusible material can be significantly reduced.

  The method of the present invention is applicable to cutting tools and tools having at least one cutting edge that is coated with a fusible polymer coating. The method of the present invention is particularly applicable to razor blade cutting edge coatings. The terms “cutting tool” and “cutting instrument” should be understood to include the tool / instrument itself, as well as the cutting edge part when the tool / instrument is manufactured. In the case of a razor blade, the “cutting tool” refers to any cutting edge precursor used in its manufacture, for example a finished razor blade as well as a continuous reel featuring at least one cutting edge. Including.

  The pretreatment of the razor blade for coating in the present invention is similar to that used in the prior art, preparing a surface that dissolves the grease and dirt deposited on the blade and accepts the coating applied to the cutting edge To do so, the blade is first cleaned with a solvent or detergent.

  Various materials can be used to manufacture multiple blade bodies. One of the more common materials is metal, especially stainless steel. Other useful materials include ceramics, glass and other vitreous materials such as U.S. Pat. Nos. 3,543,402, 3,607,485, 3,805,387, 3,831,466. No. 4,807,360, 5,018,274, 5,048,191, 5,056,227 and 5,121,660, Can be included. The contents of these patents are hereby incorporated by reference and incorporated as an integral part of the disclosure of this application.

  After the blade has been washed and dried, before the dispersion or suspension of the fusible polymer material, any fusible polymer material used or proposed so far for application to the cutting edge, in particular to the cutting edge of a razor blade In turn, the blade is first coated with chrome or any type of thin film. Halocarbon polymers are desirable, and Krytox 1000 from E.I. du Pont de Nemorus and Company, Wilmington, DE is particularly preferred.

  Halocarbon polymers are generally present as powders that are suspended or dispersed in a suitable liquid such as an alcohol. The dispersion suspension can be applied to the cutting edge by any suitable method, such as spraying or dipping. Blade preheating is desirable to facilitate application of the suspension to the blade cutting edge.

  A dispersion or suspension of fusible polymer material is applied to the edge of the continuous strip of blade material before the continuous strip of blade material is cut into individual lengths corresponding to the entire length of one blade. obtain. Alternatively, the dispersion or suspension can be applied to the cutting edges of a number of blades stacked. After the cutting edge is coated with the dispersion, the edge is heated to melt or melt the fusible polymer material. This heating operation provides a substantially uniform coating of the molten polymer as a continuous film on the surface of the cutting edge. According to the present invention, melting of the fusible polymer material is achieved by exposing the polymer material to microwave energy.

A suitable power density of microwave energy may be provided by any of several known existing microwave generators. An example of such a generator that can be used here is a gyrotron that can provide power densities reaching 10,000 KW / inch ² or higher. Gyrotrons that can be used to advantage in carrying out the method of the present invention are commercially available from Gyrotron Technology, Inc., Bristol, PA and are described in the company brochure. The contents of the pamphlet are hereby incorporated by reference and form an integral part of this application and are merged here.

  Other sources or generators of microwave energy include, but are not limited to, various types of polymer fusible materials of the type described above that are useful in the practice of the present invention. It may include klystrons and twystrons that can provide frequencies. . An example of such a source of microwave energy is disclosed, for example, in the aforementioned US Pat. No. 5,879,756.

  The use of microwave energy to melt fusible polymer particles is based on the fact that only the exposed outer surface of the blade edge is heated and the remaining blade body is generally unaffected by the heating operation. Thus, it has significant advantages over known melting techniques. The cutting edge of the blade is rapidly heated to the melting point of the polymer contained in the coating and is generally maintained at that temperature for as long as required to achieve melting of the polymer particles. As will be readily appreciated by those skilled in the art, the heating temperature, heating duration and power settings for the microwave generator will depend on the characteristics and amount of the individual fusible polymer used, the thickness of the polymer coating, and the usage. It depends on factors such as the type of microwave generator to be used. Of course, it should be understood that the heating temperature and duration must be adjusted in such a way as to avoid significant degradation of the polymer and / or adverse effects on blade hardness. The heating temperature and duration can be optimized for a particular coating operation using simple experimental techniques. For many polymers, including the preferred Krytox 1000 polymer, a heating temperature of about 300 ° C. to about 390 ° C., preferably a heating temperature of about 310 ° C. to about 360 ° C., and a heating time of about 1 second to about 60 seconds, preferably A heating time of about 5 seconds to about 15 seconds can be used and good results are obtained.

  After the polymer has melted, the blade is cooled to solidify the melted polymer. One advantage of the method of the present invention is that the cooler blade body tends to function as a heat sink, resulting in extremely rapid cooling and solidification of the coating, which cooling and solidification is a conventional method in which the entire blade body is heated. Is also possible. If desired, the cooling can be facilitated by cooling the blade more rapidly, for example, to a temperature of about 5 ° C. to about 20 ° C.

Claims (8)

A method of applying a coating to a cutting edge of a cutting tool, the step of applying a dispersion or suspension of a fusible material to the cutting edge, and a substantially uniform coating adhering to the cutting edge Heating the fusible material using a microwave energy source so as to melt the fusible material. The method of claim 1, wherein the cutting edge is made of metal. The method of claim 1, wherein the cutting edge is made of ceramic or glass. The method of claim 1 wherein the fusible material is a halogenated polymer. The method of claim 1, wherein the fusible material is a low molecular weight halogenated polymer. The method of claim 1, wherein the fusible material is heated to a temperature of about 300 ° C to 390 ° C over a period of about 1 second to 60 seconds. The method of claim 1, wherein the fusible material is heated to a temperature of about 310 ° C to 360 ° C over a period of about 5 seconds to 15 seconds. The method of claim 1, wherein the microwave energy source is a gyrotron that provides a power density of up to about 10,000 KW per square inch.