Antiperspirant Composition Reactive Salt Stability
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Solution Overview
Problem
Conventional antiperspirant compositions face challenges in maintaining stability of water-soluble phosphate and non-phosphate salts in the same aqueous phase while ensuring efficacy upon application, as they tend to react prematurely, leading to ineffective sweat duct blocking.
Innovation Solution
An aqueous antiperspirant composition with a pH of 2 to 5, comprising a water-soluble phosphate salt and a water-soluble non-phosphate salt, such as calcium or magnesium salts, which form a strong bond delaying the double displacement reaction until applied to the skin, where the increased pH triggers the reaction, forming a precipitate that blocks sweat ducts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If water-soluble phosphate salt and water-soluble non-phosphate salt are mixed in the same aqueous phase, then the composition can be formulated as a single-phase product, but the salts react prematurely forming precipitates before application
Solution Approach 1:
The patent applies parameter changes by controlling the pH of the aqueous phase to a specific range (pH 2-5). At this acidic pH, the water-soluble phosphate salt and water-soluble non-phosphate salt remain stable and do not react prematurely. The low pH suppresses the double displacement reaction that would otherwise occur between the salts. When the composition is applied to skin and contacts sweat (which has a higher pH), the pH increases and triggers the formation of the water-insoluble phosphate salt precipitate that blocks sweat ducts.
2Reliability
If the composition is applied to skin, then the double displacement reaction occurs forming antiperspirant precipitate, but the salts must remain stable during storage and transport
Solution Approach 1:
The patent applies preliminary action by pre-formulating the composition with both water-soluble phosphate salt and water-soluble non-phosphate salt in the same aqueous phase at controlled pH 2-5. This preliminary preparation allows the reactive salts to be stable during storage and transport without requiring separate packaging. The composition is designed to undergo the double displacement reaction only after application to skin, when contact with sweat raises the pH and triggers precipitate formation for sweat duct blocking.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition effectively reduces perspiration by forming a non-permanent plug in sweat ducts, mimicking the efficacy of conventional metal-based antiperspirants without premature reaction, ensuring stability and effectiveness.
Implementation Method 1
specific water-soluble non-phosphate salts with water-soluble phosphate salts could be stable in the same phase at certain pH... which retards or delays the double displacement reaction... When the composition contacts with sweat... the double displacement reaction takes place
Implementation Method 2
the two salts diffuse into the sweat ducts before the double displacement reaction could begin... The double-displacement reaction product, acts like a plug which blocks sweat ducts partially or fully
Data Source
AI summary
The present invention is in the field of antiperspirant compositions, in particular, compositions comprising antiperspirant actives. Disclosed is an aqueous antiperspirant composition having pH 2 to 5, comprising a phase wherein said phase comprises: (i) a water-soluble phosphate salt; and (ii) a water-soluble non-phosphate salt; wherein said water-soluble non-phosphate salt is the salt of a carboxylic acid, amino acid or a sulfonic acid; wherein said water-soluble non-phosphate salt is selected from calcium gluconate, calcium formate, calcium lactate, calcium propanoate, calcium acetate, calcium dobesilate, magnesium citrate, magnesium gluconate, magnesium acetate, magnesium lactate, magnesium malate, zinc citrate, zinc gluconate, copper (II) acetate, copper (II) gluconate, iron (III) citrate, calcium glycinate, zinc glycinate, copper glycinate, zirconium chloride glycinate, lanthanum acetate and silver acetate; wherein said water-soluble phosphate salt is selected from monosodium phosphate, disodium phosphate, trisodium phosphate, monopotassium phosphate, dipotassium phosphate, tripotassium phosphate, monoammonium phosphate, diammonium phosphate, triammonium phosphate, lithium dihydrogen phosphate, dilithium hydrogen phosphate and lithium phosphate; wherein said composition is not a dentifrice; wherein the solubility of said salt in water is assessed at 25°C and atmospheric pressure.