Basic aluminum antiperspirant active material having enhanced activity, antiperspirant active composition containing such material, and methods for preparation of such material and composition

A basic aluminum material, with enhanced antiperspirant activity, having the empirical formula:

• Al.sub.2 (OH).sub.6-a X.sub.a,
• where 0.5.ltoreq.a.ltoreq.5.0;
• and X is an anion that is a univalent complex oxoanion of nitrogen or a halogen, which anion forms salts with Al.sup.3+ in aqueous solution so that these salts are substantially completely dissociated, which anion is readily soluble in water with metallic ions in the solutions, and which anion forms conjugate acids that are strong acids;
• wherein said material is characterized by:
• (a) size exclusion high performance liquid chromatography peaks corresponding to peak 3 and peak 4 of size exclusion chromatograms formed by HPLC technique;
• and
• (b) at least 25% by weight of the basic aluminum material is in the form of Al.sup.b polyhydroxyaquoaluminum species.

A method of forming a basic aluminum material having enhanced antiperspirant activity, comprising the steps of:

• (a) dissolving Al(Y.sup.w O.sub.n).sub.3 in water so as to form a solution, where Y is nitrogen or a halogen, w is the oxidation state of Y, and n is dependent on the oxidation state of Y;
• and
• (b) reacting aluminum metal with Al(Y.sup.w O.sub.n).sub.3 in solution so as to form a reaction product of Al.sub.2 (OH).sub.6-a (Y.sup.z O.sub.n).sub.a, where (Y.sup.z O.sub.n) is a univalent oxoanion of nitrogen or a halogen, which oxoanion forms salts with Al.sup.3+ in aqueous solutions so that these salts are substantially completely dissociated, which oxoanion is readily soluble in water with metallic ions in the solutions, and which oxoanion forms conjugate acids that are strong acids, and where 0.5.ltoreq.a.ltoreq.5.0 and o<z.ltoreq.w, the reacting being performed at a temperature, and for a time, such that the reaction product is characterized by:
• (A) size exclusion high performance liquid chromatography peaks corresponding to peak 3 and peak 4 of size exclusion chromatograms formed by HPLC technique;
• (B) a peak 4 relative area of at least 25%, a peak 3 relative area of less than 60%, the sum of the relative peak 3 and peak 4 areas being at least 50%;
• and
• (C) less than 10% chromatographic peaks eluting at shorter retention time than peak 3, corresponding to peaks 1 and 2.

A method of forming a basic aluminum material having enhanced antiperspirant activity, comprising the steps of dissolving aluminum nitrate nonahydrate in water so as to form a solution;

• and reacting aluminum metal with the aluminum nitrate nonahydrate in solution so as to form aluminum nitratohydrate, the reacting being performed at a temperature, and for a time, such that the aluminum nitratohydrate is characterized by:
• (a) size exclusion high performance liquid chromatography peaks corresponding to peak 3 and peak 4 of size exclusion chromatograms formed by HPLC technique;
• (b) a peak 4 relative area of at least 25%, a peak 3 relative area of less than 60%, the sum of the relative peak 3 and peak 4 areas being at least 50%;
• and
• (c) less than 10% chromatographic peaks eluting at shorter retention times than peak 3, corresponding to peaks 1 and 2.

A method of forming a basic aluminum material having enhanced antiperspirant activity, comprising the steps of:

• (a) dissolving Al(Y.sup.w O.sub.n).sub.3 in water so as to form a solution, where Y is nitrogen or a halogen, w is the oxidation state of Y, and n is dependent on the oxidation state of Y;
• and
• (b) reacting aluminum metal with Al(Y.sup.w O.sub.n).sub.3 in solution so as to form a reaction product of Al.sub.2 (OH).sub.6-a (Y.sup.z O.sub.n).sub.a, where (Y.sup.z O.sub.n) is a univalent oxoanion of nitrogen or a halogen, which oxoanion forms salts with Al.sup.3+ in aqueous solutions so that these salts are substantially completely dissociated, which oxoanion is readily soluble in water with metallic ions in the solutions, and which oxoanion forms conjugate acids that are strong acids, and where 0.5.ltoreq.a.ltoreq.5.0 and o.ltoreq.Z.ltoreq.w, the reacting being performed at a temperature, and for a time, such that the reaction product is characterized by:
• (A) size exclusion high performance liquid chromatography peaks corresponding to peak 3 and peak 4 of size exclusion chromatograms formed by HPLC technique;
• and
• (B) at least 25% by weight of the basic aluminum material is in the form of Al.sup.b polyhydroxyaquoaluminum species.