MXPA99011141A - Lubricating shaving aid - Google Patents

Abstract

The present invention is directed to a lubricating shaving aid (10) on a shaving razor (Fig.5) or a shaving cartridge to reduce frictional drag between a razor blade edge (16) and a shaver's skin and to provide a lubricating film on the shaver's skin during wet shaving. The lubricating shaving aid (10) comprises a water soluble polyacrylamide and a water insoluble polyurethane. The invention further discloses a method for making the same (Fig.11).

Description

AUXILIAR LUBRICANT TO SHAVE FIELD OF THE INVENTION The present invention relates to a lubricating aid for shaving, for use with a wet shaver in order to improve the ease with which a razor blade or shaving cartridge can be dragged across the skin. during shaving. More specifically, the invention relates to a lubricating aid for shaving with a better service life and to a process for producing it.

BACKGROUND OF THE INVENTION Two main types of shaving aids are known. The first type is shaving aids insoluble in water and the second type is auxiliary for shaving lubricants, soluble in water. Water-insoluble shaving aids are designed to become slippery when wetted without depositing a film on the wearer's skin during wet shaving. On the other hand, water soluble shaving lubricating aids are designed to deposit a lubricating film on the wearer's skin during wet shaving. Most lubricating shaving aids contain a water soluble component dispersed in a water-insoluble matrix. As used herein, the term "service life" is applied to a lubricant-type composite matrix that contains at least one water-soluble component therein. The term "service life" refers to the amount of time, sometimes provided as the amount of shaving, necessary to completely exhaust the water-soluble lubricant component of the shaving aid from the water-insoluble matrix during wet shaving. Substantial depletion of the water-soluble component from the shaving aid usually exposes the rigid water insoluble matrix and further causes the surface of the shaving aid to become irregular and rigid, thereby increasing its coefficient of friction when it is dragged. on the user's skin, thus presenting a source of irritation to the skin during wet shaving. In shaving systems for wet shaving there are several factors that contribute to the discomfort during shaving. These factors include, but are not limited to, excessive wear resistance of the shaver to 'through the skin, the force necessary to cut the veil depends, among other things on the mechanical strength of the structure of the hair protein and the degree of obstruction of the parts of the shaver with metal oxide fibers, skin and other waste. Other factors of tractors include different skin conditions such as eczema, psoriasis, other rashes, erythema (redness), acne, other skin rashes and injuries and previously performed injuries. Efforts to remedy at least some of the aforementioned problems have included the use of pre-shave and aftershave lotions, soap foams or special agents to soften metal oxide fibers, blood coagulants and other medicinal agents or with biological effect. Various agents, namely shaving foams, shaving soaps, sharp beard softening agents as well as medicinal or cosmetic substances or combinations of all these have been used. These shaving agents reduce the cutting work that has to be done to separate the hair by softening the hair or act as a lubricant that reduces the frictional force between the different parts of the razor to shave contact with the user's skin. Although the comfort in shaving can, to some degree, be improved by the use of one or more of the aforementioned agents, the requirement that these must be applied before or after shaving (due to evaporation loss or repeated movements). shaving) reduce their effectiveness.

In view of these problems, it is considered that a shaving aid included in an integrated manner with or attached to the shaving instrument itself will provide improved shaving characteristics. For example, lubricating shaving aids _ integrated with or attached to the shaving instrument itself will substantially reduce the frictional resistance of the razor (s) for shaving as the shaver is drawn through the user's skin. The frictional resistance is substantially reduced by lubricating the skin at the same time during the act of wet shaving. It has been proposed to fit a strip of polystyrene insoluble in water and a water-soluble lubricant such as polyethylene oxide into a cavity in the lid of a shaver. The result was the continuous dissolution of the water soluble polymer components during the course of wet shaving and producing a lubricating film on the skin. This was expected to reduce the friction between the skin and the razor during shaving and make shaving smoother and more comfortable. For this purpose, U.S. Patent No. 4,170,821 to Booth discloses a lubricating aid for shaving (attached to a disposable razor cartridge) that dissolves a water-soluble lubricant during the act of wet shaving. The lubricant, as part of the shaving aid, was incorporated into a water-insoluble polystyrene matrix. According to Booth, the shaving aid may contain a water-soluble lubricating oil such as microencapsulated silicone oil.; water-soluble polyethylene oxide; nonionic polyacrylamide; and / or a natural polysaccharide from plant materials, for example, guar gum; a depilatory agent; a medicinal agent to kill bacteria or repair the condition of the skin; a cosmetic agent to soften the skin; or a blood coagulant. However, there are some disadvantages that are recognized in the art when using shaving aids such as those described by Booth '821. the water-soluble lubricant dissolves or leaves the water-soluble matrix during wet shaving, leaving behind the insoluble matrix in depleted water. Usually, when the water-soluble component of the shaving aid is almost exhausted, the lubricating aid for shaving is at the end of its service life. It has been reported in U.S. Patent No. 4,872,263 to Ethredge, III, that the Booth shaving aid has some disadvantages that include an average service life of three shaves. Afterwards, its surface becomes irregular and rigid and its coefficient of friction increases, contributing to a greater irritation of the skin with continuous use. At this stage, only a slight amount of lubricant can be provided, if provided, by the shaving aid. It is at this point when the cutting action and the comfort of shaving the razor have been deteriorated through use, that it is necessary to perform additional lubrication. However, due to the relatively short service life of the Booth shaving aid, an adequate amount of lubricant is no longer available. In contrast to lubricating aids for shaving, the water-insoluble xerogels of polyvinylpyrrolidone and polyurethane were developed as described, for example, in US Patent No. 5,056,221 to Theone. With exposure to water during wet shaving, xerogels swell in lyogels that are more slippery on the user's skin than in their dry xerogel state. The colloidal substance that forms the lyogel, however, does not pass into solution and, consequently, does not provide a lubricating film on the wearer's skin during wet shaving. Other water insoluble shaving aids include hydrogels (e.g., polyvinylpyrrolidone / polyurethane hydrogels from US Patent No. 4,857,287 to Creasy et al.), Interpolymers (e.g., polyvinylpyrrolidone / polyurethane interpolymers from U.S. Pat. 5,005,287 of Riter) and the like. Although lubricant depletion is not found with water-insoluble shaving aids, it is preferred to provide a lubricating shaving aid for greater shaving comfort. It is further preferred to provide a shaving aid having a slow dissolving speed to increase the service life of the shaving aid and for greater comfort of wet shaving. The slow dissolving speeds prolong the service life of the lubricant assistant for shaving and delay the leaching of all (or almost all) in auxiliary shaving lubricant. It is further desirable to provide a lubricating shaving aid that deposits a film of the water-soluble polymer component thereof and the water-insoluble polymer component thereof or on the wearer's skin during wet shaving for improved shaving comfort and to provide a method to manufacture the same. It is further desirable to provide a shaving lubricating aid that deposits a film of the water-soluble polymer component thereof and the water-insoluble component thereof wherein the latter component is released gradually and uniformly without imparting a rigid surface for the shaving aid, keeping for this

Claims (1)

1. Means a low coefficient of friction and a smooth profile. SUMMARY OF THE INVENTION These and other objects are carried out by means of a lubricating shaving aid provided in a razor for shaving or in a shaving cartridge. The shaving aid according to the present invention is attached to a shaving cartridge or a razor containing one or more razors. With the wetting and passage of the cutting edge (s) of the razor to shave through the skin, the shaving aid comes into contact with the user's skin, thereby lubricating the skin over the affected area. In accordance with the present invention, the shaving aid is provided as a solid dispersion. The shaving aid consists of a dispersion of polyacrylamide and polyurethane. During shaving, the shaving aid releases a lubricating film of the dispersion on the user's skin when it is wet. Established otherwise, the polyacrylamide and polyurethane components of the solid dispersion are deposited as a lubricating film on the wearer's skin during wet shaving for greater shaving comfort. Thus, the shaving aid of the present invention provides greater lubricating properties, a smooth profile, a longer service life and a lower friction coefficient than other lubricating shaving aids known in the art. The shaving aid is made by a process that involves immersing, for example, a thermoplastic material (for example polyester, polystyrene, acrylonitrile butadiene styrene, etc.) in an aqueous bath containing polyacrylamide and polyurethane. After immersion of the thermoplastic material in the bath for a sufficient time, a layer of the slurry of the shaving aid is deposited therein. The slurry layer is then dried. Then, the thermoplastic material, which contains a layer of dry shaving aid deposited thereon, fits into a shaver component for shaving or a shaving cartridge component. Methods for adjusting the thermoplastic material include ultrasonic welding, interposing an adhesive layer, and so on. The details of the invention will be readily apparent from the following description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a side view of a cover portion of an exemplary shaving unit; FIGURE 2 is a top view of a lid portion • depicted in FIGURE 1; FIGURE 3 is a bottom view of the lid portion shown in FIGURES 1 and 2; FIGURE 4 is a top view of a razor and shaver of an exemplary unit for shaving; FIGURE 5 is a side view of a platform of the exemplary shaving unit attached to a handle to accept the shaver of FIGURE 4 and the lid portion of FIGURES 1, 2 and 3; FIGURE 6 is a top view of the platform of the shaving unit of FIGURE 5; FIGURE 7 is a bottom view of the platform of the shaving unit of FIGURES 5 and 6; FIGURE 8 is a side view of an exemplary safety closure for attachment to an exemplary assembled shaving razor; FIGURE 9 is a top view of the security lock of FIGURE 8; FIGURE 10 is an exemplary view of a cut of the lid 20 depicting the shaving aid 10 indirectly attached to the lid 20 using an adhesive layer 10c; and FIGURE 11 is a flowchart that outlines an exemplary process for manufacturing the lubricating aid for shaving of the presently claimed invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a razor provided with a lubricating aid for shaving is described below with reference to FIGS. 1-10. The model razor is assembled by fitting it together with the lid 20, the razor 14 and the platform 24 (see FIGURES 2, 4 and 6). Each of these components is adjusted to each other by placing the razor 14 on the platform 24, then placing the lid 20 on the razor 14 with the legs of the lid 12 aligned to fit through the holes of the razor. for shaving 18 and the holes of the platform 22. During storage, to fit snugly in juxtaposition therein, the security lock 30 can be adjusted over the head of the razor for shaving by assembling the platform 24, the knife for shave 14 and lid 20 as described. Further, although the handle 26 is shown to be permanently attached to the platform 22, the platform 22, the razor 14 (or a plurality of razors for shaving, are not shown) and the lid 20 with the lubricating aid for shaving 10 may forming a disposable razor cartridge that can be replaced with a new cartridge in the handle 26 when necessary. The present invention provides a shaving lubricating aid normally placed on the upper surface of the lid 20 as shown in FIGURE 1. The shaving aid of the present invention consists of a dispersion of at least one water-soluble polymer component as it can be polyacrylamide and a water insoluble component such as polyurethane. FIGURE 11 outlines the exemplary process steps for forming the shaving aid manufactured in accordance with the present invention. As seen in FIGURE 11, • Step Si is directed to provide a backing 32 made of a thermoplastic material (or a substitute material) in a desired form as a sheet, a strip or the like having the desired thickness, preferably from about 0.1 mm to about 0.5 mm. However, it is possible to use other thicknesses. The thermoplastic material is preferably extruded in heat. However, it is possible to use any suitable method known in the art as injection molding to provide a thermoplastic support of desired shape and thickness. Examples of thermoplastic materials suitable for use with the shaving aid of the present invention include, but are not limited to, polyesters, polystyrenes, acrylonitrile butadiene styrenes, nylon or other thermoplastics that can be molded by extrusion or injection. In addition, although a thermoplastic material is preferred, it is possible to use any suitable material such as a metal, preferably a porous metal layer, a rubber, a variety of other polymers or the like in place of the thermoplastic which is capable of physical or chemical bonding to the polyacrylamide and polyurethane slurry layer such as, for example, the one referred to in step S2 of FIGURE 11. In step S2, the hot, extruded thermoplastic support 32 for the same is immersed in a cooling bath consisting of in an aqueous solution of the shaving aid at a bath temperature of preferably about 40 ° F, for a time, preferably from about 2 to about 5 minutes, sufficient to cool the extruded support element 32 and to form the slurry layers of the shaving aid 34 and 36 with a thickness of the slurry in the support 32, preferably, from about 20 to about 100 thousand in the same. According to one embodiment of the present invention, the aqueous solution of a water-insoluble polyurethane and a water-soluble polyacrylamide in the cooling bath is applied to the extruded support surfaces 32 (see FIGURE 10). Furthermore, it is possible to add a blowing agent to the thermoplastic material, preferably during extrusion or during injection molding of the support element 32. The blowing agent provides a more porous, sponge-like structure to the thermoplastic material or to the layer intermediate. In effect, the blowing agent imparts a greater surface area to the thermoplastic support element for greater absorption and / or adsorption of the slurry layer of the lubricating auxiliary for shaving polyacrylamide and polyurethane during immersion in the cooling bath. Next, in accordance with step S3 of FIGURE 11, the coating layer of the slurry is dried to form the shaving aid of the present invention (e.g., layers 34 and 36 of FIGURE 10). In one embodiment of the present invention, a preferred polyester sheet is provided. The polyester sheet is submerged and passed through the cooling bath containing polyacrylamide, polyurethane, optional minor additives and water to form a slurry layer of the shaving aid on all exposed surfaces thereof. Then, in addition to step S3, the layer of the polyacrylamide and polyurethane slurry deposited on the polyester sheet is dried. The drying is carried out by means such as the oven, cured with air or ultraviolet curing. In another embodiment, the cap member 20 can be submerged in the cooling bath to cover it with the shaving aid. The coated lid element 20 can then be assembled to form a shaving cartridge. It should be noted that, when wet, the ratio (w / w) of polyacrylamide to polyurethane in the shaving aid of the present invention preferably ranges from about 1: 1 to about 1.2: 1. After drying, the sheet 10b can be cut to the size and shape suitable for application to a razor or shaving cartridge component. As an example, the self-adhesive coating layer 38 is applied to the lower surface of the layer 36 and to the portion of the lid 20 as shown in FIGURE 10. The attachment of the shaving aid 10 (as in FIGURE 10) to the lid 20 is carried out by peeling back the self-adhesive backing (not shown) from the adhesive layer 38 and adjusting the shaving aid 10 to the lid 20 as shown. The preferred adhesive is ethylene vinyl acetate. The shaving aid may be embedded, dispersed in, formed as an integral component of, or otherwise fitted to, the shaving cartridge or razor blade structure adjacent to the razor blade (s) of individual knives. or multiple supported in it. If an adhesive layer is not used, it is possible to use other adjustment techniques, for example spot welding, ultrasonic welding, the use of an adhesive, heat sealing or any other method known in the art for joining layers. The adjustment method should be at least sufficient to maintain adhesion of the shaving aid to the shaver lid or other shaver component during the service life of the shaving aid or at least while the shaver is being used under shaving conditions. wet. Unless otherwise specified, all percentages in. weight stated herein indicates * the percent by weight of a given component based on the total weight of the cooling bath. The cooling bath, preferably, consists of an aqueous polyacrylamide solution (for example,