Clear antiperspirant stick gelled with dibenzylidene sorbitol and containing a guanidine compound as gel stabilizer, and process of making same

A method of manufacturing a clear, antiperspirant metal salt-containing, gel stick composition, comprising the steps of:

• a) providing a first solution of an antiperspirant metal salt in a solvent therefor, said first solution being a liquid and containing the antiperspirant metal salt in an antiperspirant effective amount;
• b) forming a heated second solution, of (1) dibenzylidene sorbitol and (2) a guanidine compound which acts as a stabilizer for the dibenzylidene sorbitol in a solvent for the dibenzylidene sorbitol and guanidine compound, the second solution being provided by mixing solutes and the solvent in a high speed disperser mixer, the second solution being a liquid, wherein said guanidine compound is selected from the group consisting of guanidine carbonate, aminoguanidine bicarbonate, guanidine phosphate, guanidine hydrochloride, guanidine nitrate, guanidine sulfonate, guanidine bisulfate and guanidine hydrobromide, and mixtures thereof;
• c) blending and mixing the first and second solutions using a multiple heat metering pump, for a sufficiently short time such that the dibenzylidene sorbitol does not degrade and for a sufficiently long period to provide a mixture of the first and second solutions, the mixture being a liquid;
• and
• d) cooling the mixture of the first and second solutions so as to form a gel.

A method of manufacturing a clear, antiperspirant metal salt-containing, gel stick composition, comprising the steps of:

• a) transferring dibenzylidene sorbitol and a guanidine compound to a twin-screw extruder, wherein said guanidine compound is selected from the group consisting of guanidine carbonate, aminoguanidine bicarbonate, guanidine phosphate, guanidine hydrochloride, guanidine nitrate, guanidine sulfonate, guanidine bisulfate and guanidine hydrobromide, and mixtures thereof;
• b) transferring a solvent for the dibenzylidene sorbitol to the twin-screw extruder and heating the solvent;
• c) transferring an antiperspirant metal salt to the twin-screw extruder, an amount of antiperspirant metal salt transferred being an antiperspirant effective amount in the stick composition;
• d) blending and mixing the transferred materials in the twin-screw extruder, thereby forming a resulting mixture;
• e) discharging the resulting mixture from the twin-screw extruder;
• and
• f) cooling the resulting mixture to form the gel stick composition.