CA1282340C - Antiperspirant composition and process - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Nonaqueous antiperspirant compositions which comprise a nonaqueous carrier, a dry antiperspirant active suspended in the carrier and a hydrophobic, pyrogenic silica suspending agent.

Description

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ANTIPERSPIRANT COMPOSITION AND PROCESS

This invention relates to nonaqueous su6pension type antiperspirant compositions~ More particularly i~ relates to compositions of this type that are particularly suitable for being dispensed from the so called roll-on applicators.

For a long time the standard antiperspirant compositions that were dispensed from roll-on applicators took the form of aqueou~
composition that had the consistency of a lotion. These products, however, were found to be objectionable because of the "wet" and "tacky`' fee~ that was experienced when they ~ere applied.

To overcome, this objection there ~as developed in the art, essentially anhydrous su~pension antiperspirant products which could be applied from a roll-on dispenser which went on dry and avoided the "wet" and "tacky" feel noted abo~e. These prod~cts were generally antiperspirant for~ulations in which po~dered anti-perspirant materials were suspended in an essentially nonaqueousTM TM
~ilicone vehicle, by ~eans of Bentone 38 or Cab-O-Sil M5 as the suspending agent. The~e compo~itions are illustrated in U.K. Patent Application GB 2,018,590 published Oct. 24, 1979.

Although these products were improvements over the aqueous compositions they left much to be desired from a stability point of view. For example commercial antiperspirant, suspension roll-on compositions containing Bentone 38 or Cab-O-Sil M5 shows upper layer ~eparation (about 20%) when stored overnight. It was therefore necessary to shake the container significantly each time ~efore use.

It has now been found that the stability of the aforesaid anhydrous antiperspirant suspension products may be i~proved if there is used, as a suspending agent, a hydrophobic pyrogenic silica whose surface structure on the exposed portions of the silica is largely composed of hydrocarbon groups and is prepared by reacting conven-tional pyrogenic silica with an organosilane such as halo alkyl silanes (e.g. dimethyl dichloro-silan~) under conditions which ~ . . _ ............. . ........ .. . . .

, 1~ ' ' ' , ~ .' . , ,' ' '' , `:

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cause a chemical reaction to occur with a substantial portion of the hydroxyl groups on the surface of the pyrogenic silica.
An aspect of the invention is as follows:
A nonaqueous liquid antiperspirant suspension composition comprising by weight o~ the composition (a) from about 30 to about 85% of a nonaqueous carrier, (b) a dry, particulate active antiperspirant material suspended in said nonaqueous carrier, said antiperspirant material being present in said composition at a concentration sufficient to act effectively as an antiperspirant, and (c) from about 3 to about 8~ of a suspending agent from said antiperspirant material which agent is a hydrophobic, pyrogenic silica, the surface structure of said silica having exposed portions, the major portion of which is co~prised of hydrocarbon groups, said composition being a flowable admixture of the constituents.

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Pyrogenic silicas of the a~oresaid type have been used in a number of applications in the antiperspirant art but not for the purpose for which it is prssently employed. Thus Belgian Patent 895,610 shows the use of this type of pyrogenic silica as an emulsifying agent in emulsifying an aqueous solution of antiperspirant materials in an oil. International Patent Application Wo 80/02293 teaches the preparation of a dry antiperspirant product which is converted to a cream when it is subjected to shearing action. This is prepared by high intensity mixing of an aqueous solution of antiperspirant with the pyrogenic silica.
The pyrogenic silicas employed in the present invention are distinguished from the generally conventional pyrogenic silica (e.g. Cab-0-Sil) by its mode of preparation which gives it its particular hydrophobic character. These hydrophobic products are prepared by reacting the conventional pyrogenic silica with an organosilane such as halo alkyl silanes (e.g.
dimethyl dichlorosilane) under conditions which cause a chemical reaction to occur with a substantial portion of the hydroxyl groups on the surface of the pyrogenic silica. This gives a new surface structure on the outer or exposed portions of the silica which is largely composed of hydrocarbon groups.
The preparation of hydrophobic silicas that are useful for the purposes of the present invention are described in U.S. Patent 3,393,155 col. 2, line 25 to col. 3, line 18 and in the Example, col. 3, line 70 to col. 4, line 6.
As pointed out therein, the pyrogenic silicas that may be employed in preparing the hydrophobic silicas that can be used herein are those having a surface area of at least about 100 sq. meters per gram and mean equivalent particle diameters of less than 50 millimicrons per gram. In order to provide a 3a '.~

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sufficiently hydrophobic surface on said silicas for the purpose of this invention, it is merely necessary to attach thereto in suitable concentration chemical complexes bearing hydrocarbon or similar organo groups.
The molar concentration of such complexes required per unit of surface area will depend somewhat on the number and size of the organo groups therein. However, for the organo silane complexes of primary interest, which carry from 1 to 3 organo groups mostly of smaller size (e.g.
usually not over 7 carbon atoms per group), the concentrations of the attached chemical complexes should be in the range of about 0.2 millimoles or more per 100 sq. meters of surface area of the silica. For the preferred silicas having BET surface areas of at least about 150 sq. meters per gram, the carbon content after surface treatment to provide a suitable hydrophobic character will usually be about 1% by weight or more.
A number of hydrophobic silicas sold commercially are employable in the present invention. These include "Aerosol R 972--~M or "Silica R 972"TM (Degussa Inc.), "Tullanox 500"TM (Tl~lco Inc.), "Silanox"TM (Cabot Corp.), Cab O-Sil N 70-TSTM etc. A material of choice is Silica R 972 currently marketed by Degussa Inc.
In preparing the compositions of this invention the antiperspirant material will be suspended in the nonaqueous liquid vehicle using as the suspending agent the pyrogenic silica defined above. The quantity of pyrogenic silica that will be employed for this purpose will vary with the quantity of vehicle and antiperspirant employed, the character of the product desired, etc. Generally, however, this will constitute from about 3% to about 8~ by weight based on the total weight of the composition, the preferred range being from about 4% to about 7% on the same weight basis.
A variety of anhydrous liquid vehicles may be utilized in manufacturing the present products. These ~az;3~
will usually be volatile oily organic liquids many of which are known in this art as being useful in preparing suspension type antiperspirant products. By way of example mention may be made of Cyclomethicones and mixtures thereo~. In the pre~erred form of this invention the nonaqueous vehicle will be constituted primarily by one or more volatile silicones ti.e. one or more Cyclomethicones).
A number of volatile silicones are available on the market which may be employed for the present purposes.
These include such materials as Volatile Silicone 7158 (Union Carbide), Siloxane F-222 ~SWS SILICONES), Dow Corning Q2-1201 Fluid, ~ilicone Fluid SF-1202 (General Electric), Volatile Silicone 7207 (Union Carbide), Siloxane Q3314 (SWS Silicones), Dow Corning X2-1145 Fluid, Silicone Fluid SF-1173 (General Electric) etc.
Additional examples of Cyclomethicones that may be employed are given in the CTFA Cosmetic Ingredient Dictionary, Third edition, 1982 (published by the Cosmetic, Toiletry and Fragrance Association, Inc., Washington, D.C.) at p. 600 One or more of the aforesaid Cyclomethicones may be used alone or in combination with each other.
Cyclomethicone is a cyclic dimethyl polysiloxane.
This conforms to the formula C~
~ r ~ ~ Q ~1 L c~3 - 1~ 1 I

where n has an average value of between 3 and 6.

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The quantity of anhydrous volatile liquid carrier used in the compositions of this invention may vary somewhat. Generally, this will constitute between about 30% to about 85% by weight based on ~he total weight o-f the composition with preferred range being from about 40~ to about 75% on the same weight hases.
It is a feature of the compositions of this invention that the active antiperspirant material is suspended in the nonaqueous vehicle employed herein.
This material is employed in a dry particulate form as for example as powders, granules, crystals etc. that is intimately distributed in the vehicle. The particle sizes of these materials can vary widely but usually they will be in the range o~ from about 5 micron to 70 micron is size.
Any of the variety antiperspirant materials well known to those skilled in thus art may be used for the present purposes. These include such materials as aluminum chlorohydrate, aluminum sesquichlorohydrate, and Al/Zr polychlorohydrate glycine or their combinations. The aluminum zirconium polychlorohydrate complexes that may be incorporat~d in the composition of the present invention may be described by the general formula:

5a ~r ~' :, ' ' ~ 32;~
(I) AlxZr(OH)yClz . nCH2COOH . mH20 wherein:

(a) x is a number from 2 to 10;
(b) z is a number from 3 to 8;
(c) y equals (3x +4) - z;
Id) the sum of y + z is a numher from 10 to 34 (e) m i9 a number from O to 12:
(f) n is a number from 0 to 3 y ordinarily will have a value of from about S to about 29.

As will be clear from Formula I, the glycine may he bound in the complex or it may be absent. The presence or absence of the glycine in the complex will determine the amount of unbound glycine or other buffer that may be incorporated in the composition to increase the pH to a level of from about 2.5 to about 4.5 or the preferred pH of about 2.8 to about 3.8.

A number of aluminum zirconium polychlorohydrate complexes are known in the prior art which are useful for the present purpose~.
By way of example, the fo~lowing may be mentioned along with their empirical formulas: aluminum zirconium tetrachlorohydrate (A14Zr(OH)12C14~; aluminum zirconium tetrachlorohydrate glycine (Wickenol #E-369) ~A14Zr(OH)12C14) . NH2CH2COOH);
aluminum zirconium trichlorohydrate (A14Zr(OH)13C13); aluminum zirconium trichlorohydrate glycine (A14Zr(OH)13C13) . NH2CH2COOH, aluminum zirconium pentachlorohydrate (AllOZr(OH~29C15); aluminum zirconium pentachlorohydrate lOZr(OH)29C15) ~1H2CH2CH); aluminun zirconium octachlorohydrate (A16Zr(OH)14C18?; aluminum zirconium octachlorohydrate glycine (A16Zr(OH)14Cl~) n NH2CH2COOH). The aluminum zirconium polychlorohydrate complex can be mixed individually with the ACH and AIC13 . 6H20 in solution or powder form or in various combinationq thereof.

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The OTC Panel on antiperspirants of the Food and Drug Administration has adopted certain nomenclatures and specifications for various aluminum zirconium polychlorohydrates that are useful in the pr~sent invention. These are set out in Table A below:

~E A

Panel Adopted Metal-Halide Al/Zr No~lature Ratio Ranqe Ratio ~e Alum~m zirconium 2.1 dcwn to but 2.0 up to but trichlorQhydrate ~ n~t inclu~ not incl~
1.5:1 6.0:1 Aluminum zirconium 1.5 dGwn to and 2.0 up to but tetrachlor~hydrate incl~ 0.9:1 not mcl~
6.0:1 Alum~m zirconium 2.1 down to but 6.0 up to and pentachlorohydrate not incl~ including 1.5:1 10.0:1 ~luminum zirconium 1.5 down to and 6.0 up to and octachlorQhydra~e inclu~ 0.9:~ includ~
10.0:1 Exceptionally good results are obtained with aluminum/zirconium tetrachlorohydrex glycine (CTFA
nomenclature Aluminum Zirconium Tetrachloxohydrex Gly) complexe~ employed in dry powdered form. This material will have a particle size of up to about 70 microns.
These materials are available under the trade names WICKENOL-369TM (Wickhen), REZAL 36 GPT~ (Reheis) and WESTCHLOR ZR 35 BTM (Westwood).
The quantity of active antiperspirant material usable in this invention may vary depending upon the nature of the other ingredients selected and the results desired. Usually, this will comprise from about 5% to about 30% by weight based on the total weight of the composition with the best results being obtained when the active antiperspirant constituted from about 10% to about 25% on the same weight bases.
It is often highly desirable to also incorporate in this composition a nonvolatile liquid emollient. This will add to the elegance of the product giving it enhanced organoleptic properties. Numerous nonvolatile liquid emollients may be employed for this purpose.
These includa such materials as nonvolatile linear polydimethylsiloxanes. Of special interest are the dimethicones having a viscosity of from about 100 cs to about 1,000 cs (and preferably about 350 cs).
These materials are described in the CTFA Cosmetic Ingredient Dictionary, Third edition, 1982 of page 83, and conform to the formula ~3 ~ ~ IS ~ - ~ ~ S~,- C ~3 These are available commercially as Silicone Fluid SF18 (General Electric~, Silicone Fluid SWS-101 (SWS
Silicones), Silicone Fluid 200 (Dow Corning).
Other suitable non-volatile oils for this purpose (which in conjunction with the volatile silicones form the liquid carrier for this invention) are organic oily liquids which are non-polar in character and have (a) a boiling point under atmospheric pressure not lower than about 120C; (b) a speci~ic gravity between about 0.7 and ~.6, preferably between 0.7 and 1.2. These include such materials as liquid hydrocarbons (mineral oil, Iso-Par); fatty acid esters (isopropyl myristate, 2-ethyl hexyl palmitate); diesters of dicarboxylic acids (diisopropyl adipate) polyoxyalkylene glycol esters (polypropylene glycol 2000 monooleate); propy~ene glycol diesters of short chain fatty acids (C8-C10) (Neobee-M20); polyoxyethylene ethers (polyoxyethylene (4) lauryl ether (Brij 30), polyoxyethylene (2) oleyl ether (Brij 92), polyoxyethylene (10) oleyl ether (Brij 96, Volpo 10); polyoxypropylene cetyl ether (Procetyl); higher fatty alcohols (oleyl, hexadecyl, lauryl) propoxylated monohydric alcohol M.W. 880-930 (Fluid AP). Mixtures of the above non-polar liquids are equally suitable for the purposes of this invention.
The quantity of nonvolatile liquid emollient that will be contained in the present composition is variable. Usually this will constitute between about 2%
to about 20% by weight based on the total weight of the composition. The pre~erred range being from about 5%
to about 15% on the same weight basis.

8a !!~' .: , . .
~ ~ , , 3~3 In addition to the components described above the compo~itions of the present invention ~ay, optionally contain a number of other ingredients. Thus it might contain processing aids, odor maskin~
agents, perfumes, coloring agents, etc. A polyethylene powder, as for example, a pr~duct sold under the trade name Polymist B-~s useful as a suspending aid. As an odor mas~ing aid ethylene tridecanedioate (sold under ~he trade name Ethylene Brassylate, Musk T-Takasago), pentadecalactone, (sold under the trade n~me Exaltolide, by Firmenich), and 1,3,4,6,7,8 - hexahydro - 4,6,6,7,8,8 -hexamethylcyclopenta - gamma -2 - benzopyran (sold under the trade name Galoxolid 5~y International Flavors and Fragrances, Inc.) have been used with advantage.

The antiperspirant suspensions of the present invention can be generally prepared by dispersing 'cSIe hydrophobic, pyrogenic silica in a mixture of liquid emollients and silicone, if any, and then mixed until wet and homogeneous. Subsequently all other powders can be added, including actives and polyethylene, if any. The above suspension is homogenized with a Warin~ blender for 6 minutes at low speed. Other homogenizers, such as Menton Gaulin homogenizer, Eppenbach Homomixer can also be used in this invention.

Then perfume or masking agent is added.

The following e~amples are given to further illustrate the present invention. It is to be understood, however, that the invention is not limited thereto:

EXAMPLE I
A/P SUSPENSION ROLL-ON

%(W/W) 1. Al/Zr Tetrachlorohydrex Gly 24.00 2. Aerosol R972 5.00 3. Dimethicone 350 C.S. 10.00 4. Polyethylene B-6, 6 micron powder5.00 (Polymist B-6) 5. Cyclomethicone 7158 33.59 6. Cyclomethicone 7207 22.39 7. Ethylene Brassylate 0 02 .

EXAMP LE I I
-~ ( W/W ) 1. Aluminum chlorohydrate impalpable powder 24.00 2. Aeros~l R972 5.00 3. Dimethicone 350 C.S. 10.00 4. Polyethylene B-6, 6 micron powder 5.00 5. Cyclomethicone 7158 33 59 6. Cyclo~ethicone 7207 22.39 7. Ethylene Brassylate _ 0.02 10~. 00 _ % (W/W ) 1. Aluminum Sesquichlorohydrate-Gly 24.00 2. Aerosol R972 5.00 3. Dimethicone 350 C.S. 10.00 4. Polyethylene B-6, 6 micron powder 5.00 5. Cyclomethicone 7158 33.59 6. Cyclomethicone 7207 22.39 7. Ethylene Brassylate 0.02 100.00 To compare the stability of anhydrous antiperspiran~ suspension type products containing Cab-O-Sil M5 or Bentone 38 on the one hand and pyrogenic hydxophobic silicas employed in the present invention (e.g. Aerosol R972; Cab-O-Sil N70-TS) a series of compositions were prepared. After the products were prepared the following character-istics were observed and recorded (1) appearance, (2) initial viscosity (#6 sp. 20rpm), (33 color, (4) viscosity after standing overnight, (S) % separation of product. These are summarized in the Table below.

' ` . , , TABLE

Ingredient ~~W/W ~ W/W _ ~ W/W _ ~ W/W

lAl/Zr tetrachloro-hydrex gly) _ _ _ _ Cyclomethicone 7158 71 71_ 71 _ _71 _ Cab-O-Sil M5 _ _ 5.0 Aerosol R 972 ~ 5.0 Bentone 38 _ - *5~
Cab-O-Sil N-70 TS - - 5~ -(Hydrophobic) 00 _ 100_ 100 100 ~ppearance NON
FLOWABILITY FL~ABLE FLOWABLE FLOWABLE FLOWABLE
_ PASTE SUSPENSION_ SUSPENSION SUSP~NSION

VISCOSITY OVE~ S,o00 2100 CPS 1,000 CPS 760 CPS
~IGHT _ ALMOST ALMOST
NO NO
% SEPARATION CREAM10% SEPARATION SEPARATION SEPARATION

* Bentone 38 added as a 10% gel in Cyclomethicone 7158.

As will be noticed from the table the product with 5~ Cab-O-Sil M5 tBA3234-92A) was not a flowable suspension but a cream. The product using 5~ Bentone 38 showed a 10% sepaxation tBA3234-92B) whereas BA3234-92C and BA3234-92D that employ the pyrogenic hydrophobic silicas defined in the present invention show almost no separation despite a low viscosity.

Claims (9)

1. A nonaqueous liquid antiperspirant suspension composition comprising by weight of the composition (a) from about 30 to about 85% of a nonaqueous carrier, (b) a dry, particulate active antiperspirant material suspended in said nonaqueous carrier, said antiperspirant material being present in said composition at a concentration sufficient to act effectively as an antiperspirant, and (c) from about 3 to about 8% of a suspending agent from said antiperspirant material which agent is a hydrophobic, pyrogenic silica, the surface structure of said silica having exposed portions, the major portion of which is comprised of hydrocarbon groups, said composition being a flowable admixture of the constituents.

2. A composition according to Claim 1 wherein said hydrophobic, pyrogenic silica is prepared by reacting conventional pyrogenic silica with a halo alkyl silane under conditions which cause a chemical reaction to occur with a substantial portion of the hydroxyl groups on the surface of said pyrogenic silica.

3. A composition according to Claim 2 wherein said nonaqueous carrier comprises as a major component a volatile organic liquid.

4. A composition according to Claim 3 further comprising a nonvolatile liquid emollient.

5. A composition according to Claim 4 wherein said volatile organic liquid is a volatile silicone and said emollient is a nonvolatile silicone.

6. A composition according to Claim 5 wherein the antiperspirant material is present in an amount of from about 5 to about 30%; the suspending agent is present in an amount of from about 4 to about 7%; the volatile silicone is present in an amount of from about 40 to 75%, and the nonvolatile silicone is present in an amount of from about 2 to about 20%, all percents being by weight of the total composition.

7. A composition according to Claim 6 wherein (a) said volatile silicone is a cyclic dimethyl polysiloxane conforming to the formula wherein n has an average value of from between 3 and 6, and (b) said nonvolatile silicone is a methylated linear siloxane polymer conforming to the formula

8. A process for inhibiting the perspiration in a subject which comprises applying to the skin of such subject an effective amount of the composition of claim 1, 2, 3, 4, 5, 6, or 7 above.

9. The composition of Claim l or 7 wherein the viscosity of the composition is from about 850 cps to about 1600 cps.