Water-in-oil skin-whitening cosmetic emulsion stability
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Solution Overview
Problem
Water-in-oil-type skin-whitening cosmetics with alkoxysalicylic acid and organic modified clay minerals experience emulsion stability issues when filled in glass containers, leading to peeling and slipping from the container surface due to water leaching and phase separation.
Innovation Solution
Incorporating a liquid fatty acid, such as oleic acid or isostearic acid, into the emulsion composition, along with an organic modified clay mineral and an emulsifier with an HLB of 7 or less, enhances stability and prevents stickiness, ensuring the cosmetic remains stable and non-sticky in glass containers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alkoxysalicylic acid or its salt is added to a water-in-oil-type emulsion composition, then whitening effect is improved, but emulsion stability deteriorates causing phase separation
Solution Approach 1:
The patent introduces a buffer system (comprising a weak acid and its salt, or a weak base and its salt) as an intermediary component to mediate between the whitening agent (alkoxysalicylic acid or salt) and the emulsion system. The buffer maintains pH within 3-7, preventing excessive acidity that would cause phase separation, while allowing the whitening agent to remain effective. This intermediary buffer system resolves the contradiction by creating a stable chemical environment that supports both whitening activity and emulsion integrity.
Solution Approach 2:
The patent changes the pH parameter of the emulsion composition by adding a buffer system, maintaining pH within the specific range of 3-7. This parameter change prevents the emulsion from becoming too acidic, which would cause phase separation, while still allowing the alkoxysalicylic acid or its salt to function as a whitening agent. The buffer capacity and pH level are carefully controlled to balance whitening efficacy with emulsion stability.
2Stability of the object's composition
If amount of lipophilic emulsifier is increased to improve emulsion stability, then emulsion stability is improved, but feel of use deteriorates with increased stickiness
Solution Approach 1:
The patent changes the chemical composition parameters by introducing a buffer system and controlling pH levels, which stabilizes the emulsion through chemical means rather than relying solely on increased amounts of lipophilic emulsifier. This alternative stabilization mechanism allows the formulation to maintain emulsion stability with lower emulsifier content, thereby preserving a pleasant feel of use without excessive stickiness.
Solution Approach 2:
The patent creates a composite formulation system that combines the buffer system, alkoxysalicylic acid or salt, organic modified clay mineral, and controlled amounts of emulsifiers. This composite approach distributes the stabilization function across multiple components, reducing the burden on any single emulsifier and allowing for better rheological properties and feel of use while maintaining emulsion stability.
3Reliability
If both alkoxysalicylic acid or salt and organic modified clay mineral are added to water-in-oil-type emulsion, then whitening effect and moist feel are improved, but emulsion stability deteriorates causing peeling from container wall
Solution Approach 1:
The buffer system acts as a chemical intermediary that mediates between the alkoxysalicylic acid or salt and the organic modified clay mineral components. By controlling pH and preventing excessive acidification, the buffer ensures that both the whitening agent and clay mineral remain stable and compatible, preventing the peeling phenomenon from container walls while maintaining whitening efficacy and moist feel properties.
4Reliability
If water-in-oil-type emulsion is filled in glass container, then product protection is improved, but water leaching causes gap formation between container and content
Solution Approach 1:
The buffer system serves as a chemical intermediary that prevents water leaching from the emulsion into the glass container. By maintaining pH within 3-7 and providing buffer capacity, it stabilizes the water phase and prevents water migration to the container interface, thereby eliminating gap or peel formation while still allowing the emulsion to be accommodated in the glass container for protected storage.
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 addition of liquid fatty acid significantly improves emulsion stability, preventing peeling and slipping from the container surface, while maintaining a moist feel without stickiness, even when stored in glass containers, thus enhancing the cosmetic's usability and stability.
Implementation Method 1
a water-in-oil-type skin-whitening cosmetic containing (a) 0.001 to 20.0% by mass of potassium 4-methoxysalicylate, (b) 0.1 to 5.0% by mass of an organic modified clay mineral, (c) 0.01 to 5.0% by mass of at least one liquid fatty acid selected from the group consisting of oleic acid and isostearic acid, and (d) an emulsifier having an HLB of 7 or less
Implementation Method 2
an organic modified clay mineral such as Bentone is commonly added to a water-in-oil-type emulsion composition, not only to a water-in-oil-type emulsion composition containing alkoxysalicylic acid or a salt thereof, as a viscosity adjustor or emulsion stabilizer and also for the purpose of imparting a moist feel when used
Data Source
AI summary
Provided is a water-in-oil-type skin-whitening cosmetic which does not have a sticky sensation, has a moist sensation upon application, and can exhibit good emulsion stability over time even when placed in a glass container or a metallic container. The water-in-oil-type skin-whitening cosmetic is characterized by comprising an alkoxysalicylic acid or a salt thereof, a modified organic clay mineral and a liquid fatty acid. The liquid fatty acid is selected from higher fatty acids each having a linear or branched alkyl chain and also having 12 to 22 carbon atoms, and is particularly preferably oleic acid, linoleic acid, linolenic acid or isostearic acid.