WO1992015278A1

WO1992015278A1 - Shaving aid comprising a lubricant and an astringent and razor component

Info

Publication number: WO1992015278A1
Application number: PCT/US1992/000262
Authority: WO
Inventors: William E. Vreeland; Peter S. Williams
Original assignee: Warner-Lambert Company
Priority date: 1991-03-04
Filing date: 1992-01-15
Publication date: 1992-09-17
Also published as: EP0574426A1; CA2104603A1; AU1254692A; JPH06504695A

Abstract

A wet shaving system comprising a shaving lubricant of poly(ethylene oxide) and a water soluble astringent.

Description

Shavl ng aid compri sing a l ubricant and an astringent and razor component. 1 Related Application Data

This is a Continuation-In-Part of U. S . Patent Application Serial No. 07/111, 956 filed on October 21, 1987.

5

Background of the Invention

In recent years, the concept of delivering a shaving lubricant, such as poly(ethylene oxide) , from a microporous plastic strip attached to a shaving system has gained increasi popularity. The lubricant is preferably water soluble and is 0 deposited on the face during the act of shaving. It is known, for example, that most blade shavers shave repeatedly in the same area. The initial razor pass removes the foam or shaving cream and a substantial percentage of the whiskers. Repeated passes remove the remainder of the whiskers and are the primar ^ . . . . .

^J source of irritation which is substantially eliminated by the presence of a lubricant delivered to the face during the act o shaving, rather than before the shaving. Shaving foam or lath introduce lubricants before shaving commences, while poly(ethylene oxide) delivered from a microporous substrate on 0 the razor head liberates lubricating material repeatedly durin each stroke of the razor. This repeated lubrication minimizes the facial irritation which occurs during "second-stroke shaving." The term "second-stroke shaving" refers to shaving strokes which occur in an area of the face after the lather 5 initially covering that area has been removed by shaving.

Such a lubricating and delivery system was disclosed in U.S. Patent No. 4,170,821 which issued to Anthony R. Booth October 16, 1979. As disclosed in the Booth patent, poly(ethylene oxide) could be added directly to the face throu the leaching of the pure compound or by the leaching of the compound which had been admixed with a thermoplastic substrate The disclosed delivery vehicle was in the form of an essential rigid thermoplastic superstructure including microporous

SUBSTITUTE SHEET apertures throughout the surface containing poly(ethylene oxide) . These admixtures could be formed, as taught by Booth, in a variety of ways such as by extruding or injection molding the admixture. Along with these possible additives. Booth's patent suggested the use of a blood coagulant for suppression of bleeding that occurs from nicks and cuts. Blood coagulation is the sequential process in which multiple coagulation factors of the blood interact, ultimately resulting in the formation of an insoluble fibrin clot. The Booth patent disclosed that a blood coagulant could be used alone or in combination with other additives including the lubricant which are singularly and collectively referred to herein as shaving aids. Summary of the Invention

It has now been found that the use of a water soluble astringent for simultaneous dispensing with another shaving aid, preferably a lubricant, during the act of shaving, minimizes the evidence of nicks associated with shaving. The delivery of astringent essentially simultaneously with the nicking resulting from shaving, also essentially eliminates the stinging sensation associated an astringent. The combination of lubricant and astringent also reduces the sensation of razor burn which is irritation due to skin trauma associated with repeated shaving over an unlubricated area.

Brief Description of the Drawings This invention can be more readily understood by reference to the drawing in which:

Fig. 1 is a perspective view of a razor head of one embodiment of the present invention.

Detailed Description One preferred embodiment of the present invention utilizes a mixture of a lubricant useful for reducing razor drag, such as poly(ethylene oxide) , in combination with an astringent. This combination is delivered from a 1 razor head during the act of shaving making the astringent instantly available while minimizing the visible evidence of nicks, razor burn and the stinging sensation associated with the application of an 5 astringent after the nick has been perceived by the shaver.

As used herein, the term "razor head" is meant to include both a cartridge which is disposable and mounted on a permanent handle and the portion of the disposable 0 razor which corresponds to the cartridge. It is immaterial for purposes of the invention whether the lubricant and the astringent are delivered from the head of a disposable razor or from a cartridge attached to a permanent handle. Razor heads may utilize either a 5 single blade or a plurality of blades with the shaving edges in staggered relationship to each other. The blades may be separated by a spacer or by other means such as by utilizing blades having holes of different construction which correlate to indentations on posts 0 depending upwardly from the seat, downwardly from the cap, or both (see, for example, U.S. Patent 4,106,648 issued to Evan N. Chen and Edward A. Bedall) . The razor heads may also utilize only a single blade. Razor heads commonly include a guard bar which directs the flow of skin to the blade or blades, a razor platform or seat from which the guard bar depends and which supports one of the blades, and a cap for protecting the blade or blades and/or maintaining the blades in a predetermined vertical and/or horizontal configuration. The razor head may also include a back formed from either the cap or seat and a set of cams formed as part of the bottom of the blade seat. It is immaterial for purposes of this invention whether the razor head has one or two blades, is designed to be pivoting by use of the above-referred c-- to cams, or how the blades are mounted within the razor head. A razor head having a shaving aid strip according to one embodiment of the present invention is illustrated in Fig. 1 in which the razor head 10 includes blade 18, cap 22 and seat 12. Guard bar 14 extends from seat 12 and the bottom portion of the seat 12 includes channel 20 which is designed to engage a suitable mating handle for use during shaving. A shaving aid strip 24 is positioned in a recess 26 mounted on cap 22. Strip 24 can be adhesively bound to cap 22 or can be affixed in place by the use of fold over tabs or the like. It is also possible, of course, to utilize a delivery configuration other than the strip 24 but it is preferred that the shaving aid is positioned on cap 22.

A preferred lubricating strip comprises poly(ethylene oxide) . This strip may be formed of a water insoluble thermoplastic with poly(ethylene oxide) present as an admixture during the forming process as described in Booth. This combination produces a microporous delivery vehicle containing pol (ethylene oxide) in the microporous interstices as described in

Booth and the patents and articles specifically set forth in the Booth disclosure directed toward the forming of microporous vehicles.

The forming of the thermoplastic delivery vehicle as a means for discharging the leachable substrate is preferred for several reasons, among them that the shaving geometry will not be altered because the structure of the strip is formed from a water insoluble material rather than a water soluble material. According to the present invention, an astringent is substantially uniformly dispersed throughout the pol (ethylene oxide) matrix and is therefore dispersed at a low concentration. The delivered shaving aid, i.e. the combination of lubricant and astringent which is applied to the shaved surface substantially immediately after blade contact, produces a combination which unexpectedly substantially decreases the visible evidence of nicks while eliminating the discomfort normally associated with the application of an astringent. The present invention is therefore quite unlike previous astringents packaged in the form of styptic pencils which were made for application after shaving was completed.

Astringents useful in this invention are preferably water soluble and readily dispersable throughout a poly(ethylene oxide) carrier. Some astringents such as those based upon trivalent chromium are not preferred because of the possibility of adverse skin reaction associated with chromium. While this possibility is somewhat remote due to the extremely low concentrations ultimately employed in the skin, more satisfactory astringents such as those based on trivalent aluminum salts or compounds such as mixed salts of Potassium and Aluminum Sulphate are readily available. Amongst the trivalent salts, aluminum sulfate, which is a major component of styptic pencils, is particularly preferred. Other possible astringents are Magnesium Sulphate (Glaubers Salt) and Iron Sulphate.

Astringents such as aluminum sulfate are added in effective amounts sufficient to substantially eliminate the visible evidence of minor nicks during shaving, generally about 5% by weight of the poly(ethylene oxide) containing thermoplastic strip. The maximum amount of aluminum sulfate is determined by process limitations when a microporous substrate is used as the delivery system. Amounts of astringent greater than 15% by weight of the poly(ethylene oxide) containing thermoplastic strip may cause difficulties in blending during the extrusion step sometimes utilized for the manufacture of the microporous combination. While total amounts of aluminum sulfate or other astringents may vary depending on the process, it is generally preferred to keep the level below about 20%. Those skilled in the art will appreciate that, unlike a blood coagulant which acts upon the components of the blood, an "astringent" is a substance which constricts blood vessels, shrinks mucous membranes, and thereby checks the discharge of blood, lymph, or other bodily fluids from a damaged surface. The uniform overall dispersion resulting from the delivery of the astringent in the poly(ethylene oxide) , it is theorized, provides for the essentially instant constriction of blood vessels, before blood or lymph resulting from razor nicks is visually apparent. It is also theorized that the uniform dispersion of poly(ethylene oxide) eliminates the stinging often associated with the application of essentially pure concentrations of astringent with styptic pencils. In any event, the combination has proven surprisingly useful in maximizing the advantages associated with pol (ethylene oxide) and astringents.

Equally surprising is the lack of effect on the stability of the pol (ethylene oxide) lubricant due to the addition of an astringent such as aluminum sulfate. A mixture of pol (ethylene oxide) of two molecular weights and aluminum sulfate present at a level of 10% by weight of the poly(ethylene oxide) strip combination was blended, formed and stored for 71 days with periodic viscosity measurements of solutions in water indicating virtually no change in the solution viscosity of the combination when compared with an identical combination without the aluminum sulphate. Solution viscosity in these systems is used as an indicator of the stability of the molecular weight of the Polyox solution which in turn is evidence of the stability of lubricating efficacy of the Pol (ethylene oxide) lubricant.

Example 1 A subjective shaving test was designed involving 100 males over the age of 18. Subjects chosen for this test were those who claimed to nick sometimes or always when they shave. The control for this test was a standard

Super II Plus cartridge i.e. a Super II cartridge with a poly(ethylene oxide) containing strip. Each participant completed 4 shaves with each of the participants shaving with a standard Super II Plus cartridge (Super II is a trademark of the Schick Group of the Warner-Lambert Company, Morris Plains, New Jersey) and a Super II Plus razor in which the poly(ethylene oxide) containing strip included 10% aluminum sulfate by weight of the poly(ethylene oxide) containing strip. Each of the subjects shaved for 4 days with one of the razor samples and then for 4 days with the other razor sample. The order of first use was divided equally between the 100 subjects. Of the 86 subjects responding, 53% preferred the standard poly(ethylene oxide) formulation while 47% preferred the formulation with poly(ethylene oxide) plus aluminum sulfate. By statistical analysis these two percentages were found to be at parity of the 95% confidence level. There were no significant differences found by those preferring either sample with regard to complaints or evidence of satisfaction or dissatisfaction. It should be noted that this test was designed strictly as a shaving preference test with no attempt made to educate the users as to the effect of aluminum sulfate. No attempt was made to measure the number of nicks occurring with the shave. The general formulation used for this example included:

Ingredient % by weight

Medium impact polystyrene 28.9

Poly(ethylene oxide) 61

BHT 0.1 Al₂ (S0₄)₃ 10

The control differentiated from the above example in that the medium impact polystyrene was 38.9%.

The Super II Plus razor referred to above utilizes an extruded strip and in both the control and the comparison containing aluminum sulfate, the extruded strip used to form the microporous vehicle utilized polystyrene as the structural component. While the --- microporous strip can be formed by extrusion, injection molding, or compression, the percentages of the various components differ because of the relative ease or difficulty in liberation of the poly(ethylene oxide) when 5 the various processes are used. Lower levels of poly(ethylene oxide) are employed where, as is the case with extrusion, they can be more completely liberated. For this reason, extrusion is the currently preferred method of manufacture. Extrusion is also a simpler process when compared to injection molding.

Useful ranges of the components associated with the different processes referred to above are set out in the table, below.

Table I

Poly(ethylene oxide)

60-75%

50-65%

47-62% 40-55%

65-80%

55-70%

As can be seen from the above values, the amount of aluminum sulfate or other astringent dictates the level of poly(ethylene oxide) chosen. In all instances the percentages are by weight, with the remainder of the formulation made up of polystyrene preferably of the medium impact type.

Particularly preferred levels for each process are indicated in Table II below.

In all instances, it is preferred that the poly(ethylene oxide) have a molecular weight (M_w) greater than 100,000.

Example 2 Two formulations were prepared by extrusion containing medium impact polystyrene, aluminum sulfate and poly(ethylene oxide) . One of the formulations was identical to that set forth in Example 1 while the second formulation reduced the amount of polystyrene by 5% to a level of 23.9% and increased the level of poly(ethylene oxide) from 61 to 66%. These samples were compared to a sample containing no aluminum sulfate in a subjective test conducted over 4 days. In this example, each person was asked to shave one side of his face with one sample and the other side with a second sample. On the second day, the process was reversed. On the third day, the products were changed and the second formulation having increased poly(ethylene oxide) and aluminum sulfate was utilized in the same manner as day one and then the sides of the face were shaved in reverse order on day four.

Comparisons were garnered between samples having differing levels of poly(ethylene oxide) while aluminum sulfate was maintained at the same level. These samples were compared to the formulation containing poly(ethylene oxide) only. Forty four males were utilized for this test and only the subjects who showed nicking were evaluated. The total number of nicks were determined by immediately patting the side of the face shaved with a tissue and counting the number of blood spots. The data was then evaluated with the results being a directional indicator of superior resistance to nicking due to the presence of aluminum sulfate. The indication is directional because of the size of the sample rather than any failure in number. Table III below summarizes the blood spot data.

A nick, for purposes of this invention is defined as any skin damage which will produce a blood spot under the test conditions set forth above. Table III Number of Blood Spots

I II

Test Control Test Control

Poly(ethylene oxide)61% A1,(S0₄)₃ 10%

Polystyrene 28.9% BHT 0.1%

4.2

In this example, a microporous strip was prepared by compression. A formulation having the components and at the weights indicated below was mixed using a P-K Twin Shell Blender made by Patterson-Kelley, East Stroudsburg, Pa., for 30 minutes.

Formulation Weight/Percent

Pol (ethylene oxide) 55%

Polystyrene 40%

A1₂(S0₄)₃ 5%

TOTAL 100% After blending, the material was compressed without heat into inserts of the same approximate shape as the standard extruded insert in a Acromark Press Model 630-50, Berkeley Heights, NJ for 1-2 seconds at a machine setting pressure of 50 psi. This product was compared to a standard Super II cartridge without the poly(ethylene oxide) lubricant being present. Out of 38 subjects who nicked, the average number of nicks for the poly(ethylene oxide)-aluminum sulfate-containing razor was 6.0 while the standard Super II showed a value of 8.9 nicks per full face shave. By statistical analysis, the number of nicks measured from these two samples is significant at the 95% confidence level.

Examples 2 and 3 set out above indicate that a shave having significantly fewer nicks results when wet shaving with the combination of pol (ethylene oxide) and aluminum sulfate. It is also clear that the presence of an astringent such as aluminum sulfate does not interfere with the lubricity desired from poly(ethylene oxide) and apparently, the combination is comparable to the poly(ethylene oxide) razor without astringent for overall comfort.

Claims

WHAT IS CLAIMED IS:

1. A wet shaving system comprising a shaving lubricant of poly(ethylene oxide) and an effective amount of a water soluble astringent sufficient to terminate the flow of blood associated with shaving nicks essentially simultaneously with their occurrence.

2. A shaving system according to claim 1 wherein said astringent comprises a trivalent aluminum salt.

3. A shaving system according to claim 1 wherein said astringent comprises aluminum sulfate.

4. A shaving system according to claim 1 wherein said lubricant and said astringent are incorporated into a shaving aid strip and wherein said aluminum sulfate is present at a level of up to about 20% by weight of said shaving aid strip.

5. A shaving system according to claim 1 wherein said lubricant is admixed with a water insoluble thermoplastic to produce a microporous delivery vehicle for the poly(ethylene oxide) and the astringent.

6. A razor head having a thermoplastic microporous delivery vehicle comprising a mixture of poly(ethylene oxide) and a water soluble astringent.

7. A razor head according to claim 6 wherein said delivery vehicle is formed by a method selected from the grou consisting of extrusion, injection molding or compression.

8. A razor head according to claim 6 wherein said razo head comprises a cap and said delivery vehicle is in the form of a strip attached to the upper surface of said cap.

9. A razor head according to claim 6 comprising up to about 20% by weight of said astringent based on the total weight of said delivery vehicle.

10. A razor head according to claim 6 comprising up to about 10% by weight of said astringent based on the total weight of said delivery vehicle.

11. A razor head according to claim 6 comprising up to about 5% by weight of said astringent based on the total weight of said delivery vehicle.

12. A method of shaving hair from a body surface comprising the steps of: cutting said hair with at least one blade having a sharpened edge; and applying an astringent to said body surface substantially simultaneously with said cutting step.

13. A method according to claim 12 wherein said astringent comprises a trivalent aluminum salt.

14. A method according to claim 12 wherein said astringent comprises aluminum sulfate.

15. A method according to claim 12 further comprising the step of applying a lubricant to said body surface with said astringent.

16. A method according to claim 15 wherein said lubricant and said astringent are incorporated into a shaving aid strip and wherein said astringent comprises aluminum sulfate at a level of up to about 20% by weight of said shaving aid strip.

17. A method according to claim 15 wherein said lubricant comprises poly(ethylene oxide) and is admixed with water insoluble thermoplastic to produce a microporous delivery vehicle for the poly(ethylene oxide) and the astringent.

18. A method according to claim 15 wherein said astringent and said lubricant are simultaneously leached from a delivery vehicle on a razor head.

19. A method according to claim 18 comprising up to about 20% by weight of said astringent based on the total weight of said delivery vehicle.

20. A method according to claim 18 comprising up to about 5% by weight of said astringent based on the total weight of said delivery vehicle.