Aluminum-Free Antiperspirant Zinc Substantivity via pH Control
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Solution Overview
Problem
Current roll-on antiperspirant/deodorant products using aluminum salts face issues with erratic efficacy due to precipitation and solubility concerns, particularly with zinc salts, which have limited substantivity on the skin surface.
Innovation Solution
An antiperspirant/deodorant composition featuring an oil-in-water emulsion base with a mixture of steareth-2 and steareth-20 as emulsifiers, incorporating zinc-based actives like zinc oxide, zinc hydroxide, and film-forming polymers to enhance zinc substantivity on the skin, while being free of aluminum, magnesium, and calcium-based actives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If zinc salts are used as antiperspirant active, then aluminum-free formulation is achieved, but zinc precipitates as hydroxides at pH 6.5-8.0 causing erratic efficacy
Solution Approach 1:
The patent changes the pH parameter of the formulation to below 6.5, which prevents zinc hydroxide precipitation and maintains zinc solubility. This pH adjustment resolves the contradiction by enabling aluminum-free formulation while ensuring consistent zinc-based antiperspirant efficacy through controlled chemical parameters.
Solution Approach 2:
The patent uses composite emulsion systems containing zinc salts combined with specific emulsifiers and co-emulsifiers that stabilize the formulation at low pH. This composite approach maintains zinc in solution while providing the desired aluminum-free antiperspirant effect with consistent performance.
2Adaptability or versatility
If zinc oxide is used as antiperspirant active, then aluminum-free formulation is achieved, but perspiration dissolves zinc oxide depositions reducing duration of action
Solution Approach 1:
The patent adjusts the pH parameter to below 6.5, which reduces the solubility of zinc oxide in perspiration. This prevents dissolution of zinc depositions and extends the duration of action while maintaining aluminum-free formulation.
Solution Approach 2:
The patent introduces emulsifiers and co-emulsifiers as intermediary substances that enhance the adhesion and substantivity of zinc oxide to the skin. These intermediaries create a more stable deposit that resists dissolution by perspiration, thereby extending duration of action.
3Adaptability or versatility
If zinc salts are used to replace aluminum, then aluminum-free formulation is achieved, but zinc substantivity on skin surface is limited
Solution Approach 1:
The patent changes the pH parameter to below 6.5 and optimizes the concentration of emulsifiers and co-emulsifiers to enhance zinc substantivity. These parameter adjustments increase zinc deposition on the skin surface while maintaining aluminum-free formulation.
Solution Approach 2:
The patent uses emulsifiers and co-emulsifiers as intermediaries that enhance zinc adhesion to the skin. These substances facilitate greater zinc substantivity by improving the interaction between zinc salts and the skin surface, thereby increasing the quantity of effective zinc deposited.
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 provides increased substantivity of zinc on the skin, reducing apparent perspiration and minimizing side effects like stinging, burning, and tingling, with improved skin feel and stability.
Implementation Method 1
an oil-in-water emulsion base comprising: an emulsifier comprising a mixture of steareth-2 and steareth-20
Implementation Method 2
an emulsifier comprising a mixture of steareth-2 and steareth-20
Implementation Method 3
zinc salts precipitate as hydroxides in the range of pH of 6.5 to 8.0
Implementation Method 4
increased substantivity of zinc on a skin surface
Data Source
AI summary
An aluminum-free antiperspirant/deodorant composition is disclosed. The antiperspirant/deodorant may include an oil-in-water emulsion base and an antiperspirant active dispersed in the oil-in-water emulsion base. The antiperspirant active may be primarily a zinc-based antiperspirant active and the oil-in-water emulsion base may include an emulsifier comprising a mixture of steareth-2 and steareth-20; a plant-based oil, a polyol, and water.