Water-in-oil antiperspirant emulsion with silicone surfactants
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Solution Overview
Problem
Existing solid antiperspirant compositions in the form of sticks are unpleasant to apply due to a powdery and rough texture, lack freshness, and have inadequate antiperspirant effectiveness, along with poor removal from the skin during washing.
Innovation Solution
A solid composition in the form of a water-in-oil emulsion containing a discontinuous aqueous phase, a fatty phase with needle-shaped crystallites of wax having a melting point of 70-110°C, and specific silicone emulsifiers, along with antiperspirant or deodorant active agents, which provides improved texture, antiperspirant effectiveness, and easy removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional solid antiperspirant compositions are formulated with waxes and oils, then the composition maintains solid stick form, but the texture becomes powdery and rough causing unpleasant application
Solution Approach 1:
The patent changes the physical and chemical parameters of the formulation by introducing a water-in-oil emulsion system with specific HLB-balanced surfactants (combining hydrophilic and lipophilic surfactants in specific ratios). This transforms the conventional anhydrous solid stick into a structured emulsion that maintains solid form at room temperature while providing smooth, non-powdery application. The emulsion droplet size and distribution are controlled to ensure smooth texture.
Solution Approach 2:
The invention creates a composite emulsion system combining water phase, oil phase, multiple surfactants with complementary HLB values, and active ingredients. This composite structure integrates the benefits of both hydrophilic and lipophilic components, achieving a stable solid stick that applies smoothly without the powdery texture of conventional formulations.
2Ease of operation
If water is added to solid antiperspirant compositions to improve freshness feeling, then the composition becomes less stable and harder to formulate as a solid
Solution Approach 1:
The patent controls the water content and its distribution within the emulsion structure, maintaining it in dispersed droplet form rather than free water. The HLB-balanced surfactant system adjusts the interfacial tension and emulsion stability parameters, allowing water to be incorporated while preserving solid stick form and stability at room temperature.
Solution Approach 2:
The invention utilizes the phase behavior of the oil-water-surfactant system to create a thermodynamically stable emulsion that transitions from liquid components during formulation to a semi-solid stable stick form upon cooling and storage. The emulsion maintains its structured phase separation that prevents water separation while providing freshness feeling.
3Ease of operation
If conventional silicone emulsifiers are used in water/silicone deodorant sticks, then the composition improves texture, but antiperspirant effectiveness remains insufficient
Solution Approach 1:
The patent employs a composite surfactant system combining multiple surfactants with complementary HLB values (hydrophilic surfactant plus lipophilic surfactant) rather than relying on a single silicone emulsifier. This composite approach creates a more stable emulsion structure that enhances active ingredient delivery and maintains antiperspirant effectiveness while preserving improved texture quality.
Solution Approach 2:
The invention optimizes the HLB balance and surfactant concentration parameters to maximize both cosmetic performance and antiperspirant efficacy. By adjusting the ratio and types of surfactants, the formulation achieves optimal emulsion stability that facilitates effective active ingredient release and skin adhesion, thereby improving antiperspirant reliability.
4Reliability
If solid antiperspirant compositions are formulated with conventional waxes and oils, then the composition provides basic protection, but removal from skin during washing is difficult
Solution Approach 1:
The patent modifies the surfactant system parameters by incorporating HLB-balanced surfactants that provide both protective film formation and washability. The specific surfactant composition creates an emulsion that adheres sufficiently to provide protection but can be easily removed with water and mild cleansers, resolving the stickiness and difficult removal problems of conventional formulations.
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 offers a fresh, smooth application, enhanced antiperspirant performance, and easy rinsability without sticking to skin or hair, providing a more comfortable user experience.
Implementation Method 1
A solid composition in the form of a water-in-oil emulsion comprising, in a cosmetically acceptable carrier: (i) at least one discontinuous aqueous phase; (ii) at least one fatty phase
Implementation Method 2
at least one silicone emulsifier selected in the group consisting in alkyldimethicone copolyols of particular formula (I) and dimethicone copolyols of particular formula (II)
Implementation Method 3
at least one wax in the form of crystallites having a shape factor of greater than or equal to 2 and having a melting point of 70 to 110° C.
Implementation Method 4
having a melting point of 70 to 110° C.
Data Source
AI summary
The invention relates to a solid composition in the form of a water-in-oil emulsion comprising, in a cosmetically acceptable carrier: (i) at least one discontinuous aqueous phase, (ii) at least one fatty phase comprising at least one particular wax, (iii) at least one silicone emulsifier selected in the group consisting in alkyldimethicone copolyols of particular formula (I) and dimethicone copolyols of particular formula (II) and mixtures there of (iv) and at least one antiperspirant active agent and/or one deodorant active agent. The invention relates to a method for treating body odours associated with human perspiration, and in particular body odours which are especially underarm odours. The invention relates to a method for preparing a solid composition in the form of a water-in-oil emulsion as defined above.