Aluminum compositions of enhanced efficacy having high HPLC Bands III and IV
Novel aluminum antiperspirant compositions of enhanced efficacy activated by both heat and acid are produced comprising basic aluminum salts of having the formula: Al 2 (OH) 6-a X a wherein X is Cl − , Br − , l − , or NO 3 − , a is from abut 1.1 to about 1.7, with basic aluminum chloride being the preferred salt. When analyzed by SEC-HPLC at about 10% concentration (i.e., by 2% Al) in water, these compositions exhibit an SEC-HPLC Band I area of less than 10%, a Band III area of at least 20%, with a Band III/II area ratio of at least 0.7, a Band IV area of at least 20%, and have at least 60% aluminum species contained in Bands III and Band IV.
1 . An aluminum antiperspirant composition of enhanced efficacy
(a) having the formula
Al 2 (OH) 6-a X a
wherein X is Cl − , Br − , l − , or NO 3 − , a is from about 1.1 to about 1.7, and
(b) characterized by exhibiting an SEC-HPLC Band I area of less than 10%, a Band III of at least 20%, a Band III/II ratio of at least 0.7, a Band IV area of at least 20%.
2 . The composition of claim 1 wherein X is chloride.
3 . The antiperspirant composition of claim 1 wherein the aluminum to halide atomic ratio is from about 1.4 to about 1.6.
4 . The composition of claim 1 wherein the SEC-HPLC Band I area is less than about 5%, the Band III area is at least 30%, and the Band IV area is at least 25%, and at least 60% of the aluminum species is contained in Bands III and IV.
5 . A dried powder antiperspirant having the composition of claim 1 .
6 . A method of preparing an antiperspirant having the composition of claim 1 by a means selected from process steps:
(a) heating and refluxing a BAC solution having an aluminum/halide ratio above about 1.5 and a concentration of from about 10% to about 25% by weight until an HPLC Band III/II ratio of at least 0.7 is obtained, cooling the reaction product and adding thereto a strong acid;
(b) making a BAC solution by adding aluminum powder to an aqueous AIX 3 solution wherein X is Cl − , Br − and I − at reaction temperature of about 80° C. to obtain a reaction product having an aluminum/halide ratio of from about 1.75 to about 1.95 and a concentration of about 25% to 35% by weight and filtering the reaction product to obtain a clear solution and reacting said filtered solution with a strong acid; and
(c) preparing a BAC solution by reacting aluminum powder directly with an aqueous AIX 3 solution wherein X is Cl − , Br − and I − at reaction temperature of about 80° C. to obtain a reaction product having an aluminum/halide ratio of from about 1.2 to about 1.8 and a concentration of about 30% to 35% by weight.
7 . A method of preparing an antiperspirant according to process step (a) of claim 6 .
8 . A method of preparing an antiperspirant according to process step (b) of claim 6 .
9 . A method of preparing an antiperspirant according to process step (c) of claim 6 .
10 . The method of claim 6 wherein the strong acid is AlCl 3 .
11 . The method of claim 6 wherein the strong acid is hydrochloric acid.
12 . The method of claim 6 wherein the aluminum/halide atomic ratio of the composition is from about 1.4 to about 1.7.
13 . The method of claim 7 wherein the BAC solution is 20% by weight.
14 . The method according to claim 6 wherein the reaction product of the process steps (a), (b) and (c) is subjected to a drying operation.
15 . The method according to claim 9 wherein the concentration of the solution is about 30% by weight.
16 . The method of claim 8 wherein AlX 3 is AlCl 3 .
17 . The method of claim 9 wherein the aluminum to chloride atomic ratio of the composition is from about 1.4 to about 1.7.
18 . The method according to claim 8 wherein the concentration of the solution is about 30% by weight.
19 . An antiperspirant product selected from creams, aerosols, soft solids and solid sticks comprising the powder composition of claim 5 .