Clear cosmetic stick comprising dibenzylidene alditol

A clear gel cosmetic stick includes a liquid vehicle, a dibenzylidene alditol as a gelling agent, an antiperspirant salt dissolved in the liquid vehicle, and a chelating agent. The cosmetic stick comprises in percent by weight about 40% to about 95% of the liquid vehicle, from about 0.1% to about 5% of the dibenzylidene alditol, from about 0.5% to about 25% of the antiperspirant salt, and from about 0.05% to about 3% of the chelating agent. The cosmetic stick is preferably substantially free of alkaline gelling agent stabilizers such as NaOH and KOH.

BACKGROUND OF THE INVENTION 
The invention relates to clear gel cosmetic sticks which include a 
solubilized antiperspirant salt. 
Gel antiperspirant sticks typically include a liquid vehicle, an 
antiperspirant salt, a gelling agent, and one or more emollients. 
Dibenzylidene alditols like dibenzylidene sorbitol (DBS), also known as 
dibenzylidene monosorbitol acetal (DBMSA), are one type of gelling agent 
that has been used in such sticks. Dibenzylidene alditols may degrade 
during manufacture and subsequent storage of the gel stick, in part 
because of the presence of the acidic antiperspirant salt in the stick. 
One product of the degradation, benzaldehyde, can provide an undesirable 
odor. 
Various stabilizing agents have been incorporated into gel antiperspirant 
sticks containing dibenzylidene alditols in an effort to minimize 
dibenzylidene alditol degradation. Examples include sodium hydroxide, 
potassium hydroxide, sodium carbonate, zinc acetate, zinc oxide, zinc 
carbonate, potassium carbonate, diethanolamine, triethanolamine, disodium 
succinate, sodium benzoate, sodium octanoate, hexamethylenetetramine, 
urea, 2-amino-2-methyl-1-propanol, magnesium sulfate, calcium hydroxide, 
and N-(2-hydroxyethyl) acetamide. These and other stabilizing agents, 
although apparently effective to some degree in stabilizing the 
dibenzylidene alditol, may have other problems associated with them. 
Sodium hydroxide and potassium hydroxide, for example, may provide a 
composition with an undesirable odor. 
Clear gel antiperspirant or deodorant sticks are more desirable than opaque 
sticks for cosmetic reasons. 
SUMMARY OF THE INVENTION 
The invention features a clear gel cosmetic stick that includes a liquid 
vehicle, a dibenzylidene alditol gelling agent, an antiperspirant salt, 
and a chelating agent. The cosmetic stick comprises in percent by weight 
about 40% to about 95% of the liquid vehicle, from about 0.1% to about 5% 
of the dibenzylidene alditol, from about 0.5% to about 25% of the 
antiperspirant salt, and from about 0.05% to about 3% of the chelating 
agent. The cosmetic stick is preferably substantially free of alkaline 
gelling agent stabilizers such as NaOH and KOH.

DETAILED DESCRIPTION OF THE INVENTION 
A "clear" gel stick, as used herein, is a stick that is visually clear so 
that, like glass, it allows ready viewing of objects behind it. Preferred 
clear gel sticks have a turbidity measurement, expressed in Nephelometric 
Turbidity Units (NTU) of less than 150 NTU, more preferably less than 100 
NTU, and most preferably less than 50 NTU, when measured with a Hellige 
#965 Direct-Reading Turbidimeter. Preferably the gel sticks are 
sufficiently clear to enable an observer to read without difficulty 
lettering of size 0.1 to 0.6 (more preferably greater than 0.4) on a 
visual acuity chart as given in the "Documenta Geigy Scientific Tables", 
published by Ciba-Geigy Ltd of Basle, Switzerland (1971 ed.). 
By "substantially odor free" is meant that the gel stick (without any 
fragrance or fragrance masking agent) has an off-odor rating of 0 to 2, 
preferably 0 to 1, on a scale of 0 to 5 used by trained odor (or 
perfumery) experts, where 0 signifies no detectable off-odor and a rating 
of 4 to 5 is deemed unacceptable odor. 
By "stable" is meant that samples of the product, when stored at 45.degree. 
C. for three months, will not exhibit any noticeable benzaldehyde odor or 
other off-odor (i.e. retains an odor rating of 0 to 2) and will not 
exhibit any significant change in clarity or color (i.e. retains a clarity 
of better than 150 NTU and a color of 0 to 2 on the yellowness scale). 
A "chelating agent", as used herein, is a compound in which atoms form more 
than one coordinate bond with metals in solution. Preferred chelating 
agents include tetrasodium- and trisodium-ethylenediaminetetraacetate 
(Na.sub.4 EDTA and Na.sub.3 EDTA). 
The preferred clear gel sticks include a liquid vehicle, a dibenzylidene 
alditol gelling agent, an antiperspirant salt, a chelating agent, a 
hydroxyalkyl cellulose co-gellant, one or more emollients, and a 
fragrance. 
The liquid vehicle along with the gelling agents provide the matrix, or 
body, of the gel stick. Suitable liquid vehicles include one or more of 
the following: ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 
t-butanol, 2-methoxyethanol, 2-ethoxyethanol, ethylene glycol, diethylene 
glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, 
1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 
1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, diethylene 
glycol monomethylether, diethylene glycol monoethylether, 
2,4-dihydroxy-2-methylpentane, glycerin, sorbitol and the like, and 
mixtures thereof. Preferred liquid vehicles include polyhydric alcohols 
having from 3 to 6 carbon atoms and from 2 to 6 hydroxyl groups. More 
preferred are 1,2-propylene glycol (normally referred to simply as 
propylene glycol), dipropylene glycol, 1,3-butylene glycol, sorbitol and 
mixtures thereof. Most preferred as the liquid vehicle is propylene 
glycol, which may optionally include one or more of the aforementioned 
polyhydric alcohols. It is also most preferred that the liquid vehicle is 
substantially free (i.e., less than 2%) of monohydric alcohol such as 
ethanol. While the liquid vehicle may also optionally contain a co-solvent 
for the gelling agent, as described in the prior art, such is not 
preferred. 
The gel stick generally includes between about 40% and about 95%, and 
preferably between about 50% and about 92%, of the liquid vehicle by 
weight. A stick including an insufficient quantity of the liquid vehicle 
may be unclear or may provide an inadequate support matrix for the 
remainder of the components. A stick including too much liquid vehicle may 
lack sufficient quantities of one or more of the other stick components. 
The dibenzylidene alditol is the gelling agent. Examples include 
dibenzylidene sorbitol (DBS), dibenzylidene xylitol, and dibenzylidene 
ribitol. The aromatic rings in each benzylidene group may be unsubstituted 
or substituted, as described in U.S. Pat. No. 5,200,174, which is 
incorporated herein by reference. When substituted, it is preferred that 
the benzyl ring contain an electron withdrawing group at the meta 
position. Typical substituted compounds include di(meta-fluorobenzylidene) 
sorbitol and di(meta-chlorobenzylidene) sorbitol. The preferred gelling 
agent is dibenzylidene sorbitol (DBS). 
The gel stick generally contains between about 0.1% and about 5%, 
preferably between about 0.5% and about 2%, more preferably less than 
about 1.5%, and most preferably between about 0.5% and about 1.3%, of the 
dibenzylidene alditol by weight. If the gel stick includes too much of the 
dibenzylidene alditol, it may lack sufficient clarity and/or may have an 
undesirable odor. If the gel stick includes too little of the 
dibenzylidene alditol it may lack sufficient hardness. A particularly 
advantageous feature of the present invention is the use of low levels 
(i.e. less than 1.5%) of the dibenzylidene alditol gelling agent, which 
results in sticks of exceptional clarity and odor-free characteristics. 
Preferred gel sticks have a hardness of between about 40 and about 250, 
more preferably between about 60 and about 150, when measured on a TA-XT2 
Texture Analyzer (Stable Micro System, Haste Hill, England). These 
hardness measurements correlate to the grams of force required for the 
standard arrowhead-type penetration needle to penetrate the stick a 
distance of 5 mm at 1 mm per second. 
The preferred gel sticks will also include a hydroxyalkyl cellulose as an 
additional gelling agent (or co-gellant), which provides the preferred gel 
sticks with adequate hardness even when the sticks include only a low 
level of the dibenzylidene alditol. The combined use of the co-gellant 
with reduced amounts of the dibenzylidene alditol (i.e. amounts below 
1.5%) enable the production of gel sticks of exceptional clarity and 
stability. The preferred hydroxyalkyl cellulose co-gellants include alkyl 
groups with between one and five carbon atoms. The preferred co-gellant is 
hydroxypropylcellulose (e.g. Klucel HFF, Aqualon). Preferred gel sticks 
include between about 0.08% and about 1%, more preferably between about 
0.1% and about 0.5%, most preferably between about 0.2% and about 0.4%, of 
the hydroxyalkyl cellulose by weight. 
Antiperspirant salts are metal salts that have significant antiperspirant 
activity when applied to the skin of a human, and include various 
inorganic and organic salts of aluminum, zirconium, and zinc. Many 
examples of these salts are known to those skilled in the art. 
The preferred salts are any of the conventional aluminum, zirconium and 
aluminum-zirconium salts known to be useful in antiperspirant 
compositions. These salts include aluminum halides and aluminum hydroxy 
halides (e.g., aluminum chlorohydrate), and mixtures or complexes thereof 
with zirconyl oxyhalides and zirconyl hydroxyhalides (e.g. 
aluminum-zirconium chlorohydrate). 
Preferred aluminum salts are those having the general formula Al.sub.2 
(OH).sub.6-a X.sub.a wherein X is Cl, Br, I or NO.sub.3, and a is about 
0.3 to about 4, preferably about 1 to 2, such that the Al to X mole ratio 
is about 1:1 to 2.1:1. These salts generally have some water of hydration 
associated with them, typically on the order of 1 to 6 moles per mole of 
salt. Most preferably, the aluminum salt is aluminum chlorohydrate (i.e. X 
is Cl) and a is about 1, such that the aluminum to chlorine mole ratio is 
about 1.9:1 to 2.1:1. 
Preferred aluminum-zirconium salts are mixtures or complexes of the 
above-described aluminum salts with zirconium salts of the formula 
ZrO(OH).sub.2-pb Y.sub.b wherein Y is Cl, Br, I, NO.sub.3, or SO.sub.4, b 
is about 0.8 to 2, and p is the valence of Y. The zirconium salts also 
generally have some water of hydration associated with them, typically on 
the order of 1 to 7 moles per mole of salt. Preferably the zirconium salt 
is zirconyl hydroxychloride of the formula ZrO(OH).sub.2-b Cl.sub.b 
wherein b is about 1 to 2, preferably about 1.2 to about 1.9. The 
preferred aluminum-zirconium salts have an Al:Zr ratio of about 1.7 to 
about 12.5, most preferably about 2 to about 8, and a metal:X+Y ratio of 
about 0.73 to about 2.1, preferably about 0.9 to 1.5. A preferred salt is 
aluminum-zirconium chlorohydrate (i.e. X and Y are Cl), which has an Al:Zr 
ratio of about 2 to about 8 and a metal:Cl ratio of about 0.9 to about 
2.1. Thus, the term aluminum-zirconium chlorohydrate is intended to 
include the tri-, tetra-, penta- and octa-chlorohydrate forms. The 
aluminum-zirconium salt complexes may also contain a neutral amino acid, 
preferably glycine, typically with a Gly:Zr ratio of about 1:1 to 4:1. 
It is especially preferred to utilize enhanced efficacy aluminum and 
aluminum-zirconium antiperspirant salts in the gel sticks of the present 
invention. By "enhanced efficacy antiperspirant salts" is meant 
antiperspirant salts which, when reconstituted as 10% aqueous solutions, 
produce an HPLC chromatogram (as described, for example, in U.S. Pat. No. 
5,330,751, which is incorporated herein by reference) wherein at least 
70%, preferably at least 80%, of the aluminum is contained in two 
successive peaks, conveniently labeled peaks 3 and 4, wherein the ratio of 
the area under peak 4 to the area under peak 3 is at least 0.5, preferably 
at least 0.7, and most preferably at least 0.9 or higher. 
To incorporate the antiperspirant salt in the gel stick composition, it is 
preferred that the salt is first solubilized in a portion of the liquid 
vehicle. Accordingly, it is preferred to utilize polyhydric alcohol 
solutions of antiperspirant salts, especially those which contain an 
additional alkaline glycinate, such as sodium, potassium, or zinc 
glycinate. Such solubilized antiperspirant salts are described in U.S. 
Ser. No. 08/397,451 filed on Mar. 2, 1995 pending entitled Method Of 
Making Polyhydric Alcohol Solutions Of Enhanced Efficacy Antiperspirant 
Actives, and in EP 599,775, both of which are incorporated herein by 
reference. An example of such a solubilized salt, which is partially 
neutralized with zinc glycinate, is Westchlor A2Z 8106 (Westwood Chemical 
Corp.). The preparation of a preferred solubilized antiperspirant salt 
will be described below in conjunction with the examples of gel sticks. 
The additional alkaline glycinate included in the antiperspirant salt 
raises the pH of the antiperspirant salt and, as a result, reduces the 
degradation of the dibenzylidene alditol in the gel stick. It is generally 
preferred to add sufficient alkaline glycinate to the antiperspirant salt 
so as to raise the pH of an approximately 10% aqueous solution of the 
antiperspirant salt to about 4.1 to 5.0, preferably about 4.4 to 5.0. (The 
aqueous solution may be an approximately 50:50 polyhydric alcohol:water 
solution.) Preferred gel sticks which include such a partially neutralized 
salt will have a pH greater than 4.4, preferably about 4.8 to about 5.5, 
and more preferably about 4.9 to about 5.3. The pH of the finished stick 
can be measured by dissolving one part stick in ninety-nine parts water. 
The gel stick can be either an antiperspirant or a deodorant composition. 
Antiperspirant compositions generally include between 6% and about 25%, 
preferably between about 8% and about 22%, of the antiperspirant salt by 
weight. Deodorant compositions generally include between about 0.5% and 
about 6% of the antiperspirant salt by weight. It should be noted that 
reference throughout this application to weight percent of antiperspirant 
salt is intended to mean weight percent of the salt in accordance with 
conventional industry standards (i.e. including glycine and bound water). 
Examples of chelating agents include EDTA (ethylenediaminetetraacetate) 
salts such as Na.sub.4 EDTA and Na.sub.3 EDTA; 
hydroxyethylethylenediaminetriacetate (HEDTA); 
diethylenetriaminepentaacetate (DTPA); nitrilotriacetate (NTA); 
ethanoldiglycine disodium salt (EDG); diethanolglycine sodium salt (DEG); 
and 1,3-propylenediaminetetraacetic acid (PDTA). All of these are known 
and commercially available. The gel sticks generally include between about 
0.05% and about 3%, preferably between about 0.1% and about 2%, of the 
chelating agent by weight. If too little chelating agent is included, the 
stick may have less clarity, an undesirable odor, and/or undesirable 
yellowness. If too much chelating agent is included, the clarity and/or 
other properties of the stick may be adversely affected. 
The chelating agent may reduce the color (in particular the yellow color) 
of the stick that can result, for example, from the presence of residual 
iron (or other metal contaminants) that may be present in the stick from a 
variety of sources. The gel stick preferably measures 0-1 on the 
yellowness scale. Yellowness is measured by spectrophotometer at 408 nm 
with 0 corresponding to 0 ppm ferric chloride in water and 5 corresponding 
to 500 ppm ferric chloride in water. 
The chelating agent may also act as a gelling agent stabilizer by 
increasing the pH of the stick, thus reducing or eliminating the need for 
other alkaline gelling agent stabilizers such as NaOH and KOH. The gel 
sticks preferably are substantially free of NaOH and KOH and, as a result, 
do not have the odor that can result from the interaction of these 
materials with the vehicle, particularly with propylene glycol. The 
elimination of other alkaline gelling agent stabilizers, particularly NaOH 
and KOH, is a key feature of the present invention and is believed to 
substantially contribute to the odor-free characteristics of the gel 
sticks of the present invention. 
The preferred gel sticks retain one or more of the above-described 
properties, more preferably all of the above-described properties, even 
after storage at 45.degree. C. for three months. 
The emollients provide the gel stick with desirable application properties 
(smoothness, reduced tack, etc.). Examples of emollients include fatty 
acid esters such as isopropyl myristate and isopropyl palmitate; diesters 
of adipic, phthalic, and sebacic acids such as di-n-butyl phthalate, 
diisopropyl sebacate, diethyl sebacate, and diisopropyl adipate; propylene 
glycol diesters of short chain fatty acids; nonvolatile silicone oils such 
as dimethyl siloxane and dimethicone copolyol; volatile silicones such as 
Dow Corning 344 and Dow Corning 345 (available from Dow Corning), Silicone 
7207 and Silicate 7158 (available from Union Carbide), and SF 1202 
(available from General Electric); C.sub.12 -C.sub.15 alcohol benzoates 
such as Finsolv (available from Finetex, Inc.); fatty alcohols such as 
cetyl alcohol and stearyl alcohol; alkyl ether derivatives of polyethylene 
glycols, polypropylene glycols and polypropylene polyethylene glycol 
copolymers such as PPG-5-Buteth-7, PPG-5-Ceteth-20, PPG-3-1sosteareth-9 
and Glycereth-7-Diisononanoate. Many other examples of emollients are 
known in the art. The gel sticks should include a sufficient quantity of 
emollient to provide the stick with the desired application properties 
without interfering with the clarity of the product. The preferred 
emollients should be soluble in the liquid vehicle and form a clear 
solution therein. The gel sticks preferably include less than about 10%, 
more preferably less than about 3%, and most preferably between about 
0.25% and 1.25%, of emollients by weight. 
The fragrances used in the gel stick can be any conventional fragrance that 
provides the stick with a desired scent. The quantity of fragrance 
included should be the quantity needed to provide the desired scent. The 
gel stick generally includes less than about 2.5%, preferably less than 
about 1.5%, of the fragrance by weight. 
The gel sticks can contain other optional conventional ingredients such as 
humectants, hardeners such as waxes, fillers, colorants, preservatives, 
bacteriocides, UV absorbers, and the like. 
The following specific examples further illustrate the invention: 
EXAMPLE 1 
Antiperspirant Salt 
A 50% sodium glycinate solution was prepared by mixing 171 lbs. (77.6 kg) 
50% NaOH with 67.8 lbs. (30.8 kg) water, then adding 160.3 lbs (72.8 kg) 
of glycine (1:1 mole ratio of glycine to NaOH), the temperature rising 
from 25.degree. to 30.degree. C., then from 30.degree. to 35.degree. C., 
after the first and second additions respectively. To 103.3 lbs. (46.9 kg) 
of propylene glycol was added 7.8 lbs. (3.5 kg) of 50% sodium glycinate 
and the solution mixed for ten minutes. To this solution was added 33.9 
lbs. (15.4 kg) of zirconium hydroxychloride glycinate (50% aqueous ZHC-gly 
solution with a Zr:gly ratio of about 1:1). After mixing this solution for 
about ten minutes, 255 lbs. (115. Bkg) of 10% ACH' solution (prepared by 
heating 10% ACH at about 80.degree. C. for about 16 to 17 hours) was added 
and mixed for about ten minutes. This solution was preheated to about 
70.degree. to 75.degree. C. and fed continuously to a type JHE flash 
evaporator (APV Crepaco Inc., Tonawanda, N.Y.; evaporator modified by 
mounting to the top of the flash chamber a 3 foot rectification tower 
filled with about 2.5 feet of 0.5 inch ceramic Berl saddles) maintained at 
about 60 mm Hg (absolute pressure) from which was withdrawn at about 1 
gal/hr a clear solution comprising 65% propylene glycol, 30% enhanced 
efficacy aluminum-zirconium tetrachlorhydrate-glycine (more than 80% of 
aluminum in peaks 3 and 4 with peak 4 to peak 3 area ratio greater than 1 
and Gly:Zr ratio about 1.6:1 ), and 5% water. The pH of a sample of this 
solution diluted with an equal portion of distilled water was about 4.7. 
This antiperspirant salt solution was incorporated into the following 
examples. 
EXAMPLES 2 and 3 
______________________________________ 
Ex. 2 Ex. 3 
Ingredient Wt. % Wt. % 
______________________________________ 
Propylene glycol 85.60 84.80 
Al/Zr tetrachlorohydrate-gly 
11.00* 11.00* 
Dibenzylidene sorbitol 
1.00 1.30 
Na.sub.4 EDTA 0.10 0.10 
Dimethicone copolyol (ABIL B 8851) 
0.25 0.25 
Hydroxypropyl cellulose 
0.30 0.30 
Fragrance 1.25 1.25 
Diisopropyl sebacate -- 1.00 
Glycereth-7-diisononanoate 
0.50 -- 
______________________________________ 
*Weight % of salt in final composition. Salt is added in solubilized form 
as prepared in Example 1. 
Examples 2 and 3 were prepared according to the following procedure. 
Phase A: 
About 65% of the total propylene glycol mass (excluding that which is part 
of the antiperspirant salt solution) is added to an appropriately sized 
vessel. Hydroxypropyl cellulose is added and stirred well to dissolve. 
After heating this solution to 110.degree.-115.degree. C., the 
dibenzylidine sorbitol is added with stirring until completely dissolved. 
This Phase A solution is then cooled to about 100.degree. C. 
Phase B: 
About 35% of the total propylene glycol mass (excluding that which is part 
of the antiperspirant salt solution) is added to an appropriately sized 
vessel, stirred and heated to about 60.degree.-70.degree. C. The Na.sub.4 
EDTA is added and mixed well. The Al/Zr tetrachlorohydrate-gly solution 
(as prepared in Example 1 ) is added and the solution mixed well until it 
becomes clear and homogenous. The emollients (i.e. diisopropyl sebacate or 
glycereth-7-diisononanoate and the dimethicone copolyol) are then added 
and the Phase B solution is mixed well until clear. 
Combined Phase: 
Phase B is added to phase A with mixing and cooled to about 80.degree. C. 
The fragrance is added and allowed to mix well. The product is poured into 
suitable stick containers and cooled to solidify. 
EXAMPLES 4 and 5 
______________________________________ 
Ex. 4 Ex. 5 
Ingredient Wt. % Wt. % 
______________________________________ 
Propylene glycol 86.00 83.30 
Hydroxypropyl cellulose 
0.30 -- 
Dibenzylidene sorbitol 
0.50 0.50 
Al/Zr tetrachlorohydrate-gly 
11.00* 11.00* 
Na.sub.4 EDTA 0.20 0.20 
Glycereth-7-diisononanoate 
0.50 0.50 
Dimethicone copolyol (ABIL B 8851) 
0.25 0.25 
Fragrance 1.25 1.25 
______________________________________ 
*Weight % of salt in final composition. Salt is added in solubilized form 
as prepared in Example 1. 
Examples 4 and 5 were prepared by procedures analogous to the procedure 
used to prepare examples 2 and 3. 
EXAMPLE 6 
______________________________________ 
Ingredient Wt. % 
______________________________________ 
Propylene glycol 84.95 
Hydroxypropyl cellulose 
0.30 
Dibenzylidene sorbitol 
1.00 
Al/Zr tetrachlorohydrate-gly 
11.00* 
Glycereth-7-diisononanoate 
0.50 
Dimethicone copolyol 
0.25 
NaOH 0.55 
Na.sub.4 EDTA 0.20 
Fragrance 1.25 
______________________________________ 
*Weight % of salt in final composition. Salt is added in solubilized form 
without added glycinate. 
Example 6 was prepared by a procedure analogous to the procedure used to 
prepare examples 2 and 3. 
EXAMPLE 7 
Deodorant 
______________________________________ 
Ingredient Wt. % 
______________________________________ 
Propylene glycol 93.75 
Al/Zr tetrachlorohydrate-gly 
2.00* 
Na.sub.4 EDTA 0.20 
Dibenzylidene sorbitol 
1.30 
Hydroxypropyl cellulose 
0.50 
Oleth-10 0.75 
PPG-10 butanediol 0.75 
PPG-3 myristyl ether 
0.75 
______________________________________ 
*Weight % of salt in final composition. Salt is added in solubilized form 
as prepared in Example 1. 
Example 7 was prepared by a procedure analogous to the procedure used to 
prepare examples 2 and 3.