Gemini Surfactant and Semi-Crystalline Polymer Emulsion
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Solution Overview
Problem
Cosmetic emulsion compositions with high fatty phase content (>10% by weight and >40% non-volatile oil) face issues of greasiness, tackiness, shininess, and instability, particularly when combined with organic UV screens, leading to inhomogeneous mixtures.
Innovation Solution
Incorporating a gemini surfactant in combination with a semi-crystalline polymer in a physiologically acceptable medium to create stable, homogeneous oil-in-water emulsions that maintain pleasant texture and compatibility with destabilizing materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cosmetic compositions comprise more than 10% by weight of fatty phase containing more than 40% by weight of non-volatile oil, then they can make up for the lack of cutaneous lipids in dehydrated skin, but they generate a greasy effect, sometimes accompanied by a tacky effect and/or a shiny appearance
Solution Approach 1:
The patent changes the chemical parameters of the emulsion system by introducing a specific gemini surfactant with two hydrophobic chains (each containing 8-20 carbon atoms) connected by a spacer, and combining it with a semi-crystalline polymer. This parameter change in surfactant structure and composition allows the system to maintain high fatty phase content while eliminating the greasy effect through improved interfacial properties and emulsion stability.
Solution Approach 2:
The patent employs a composite emulsion system combining a gemini surfactant (a specialized surfactant structure) with a semi-crystalline polymer. This composite approach creates a synergistic effect where the surfactant provides emulsification and the polymer provides structural stability, allowing high fatty phase content without the typical sensory drawbacks of greasiness and tackiness.
2Quantity of substance
If emulsion-type compositions are combined with large amounts of UV screens, in particular organic UV screens, then they provide photoprotection, but they affect the stability of the emulsion and can initiate demixing
Solution Approach 1:
The patent modifies the emulsion's physical and chemical parameters by using a gemini surfactant with specific chain lengths (8-20 carbon atoms) and a semi-crystalline polymer with controlled molecular weight (≥2000). These parameter changes enhance the emulsion's robustness, allowing it to accommodate large amounts of organic UV screens without demixing, as the strengthened interfacial film and polymer network prevent phase separation even under destabilizing conditions.
3Quantity of substance
If cosmetic compositions comprise more than 10% by weight of fatty phase containing more than 40% by weight of non-volatile oil, then they are advantageous for making up for the lack of cutaneous lipids, but they show a lack of stability when combined with certain materials
Solution Approach 1:
The patent creates a composite system where a gemini surfactant (with its unique dual-hydrophobic-chain structure) works synergistically with a semi-crystalline polymer. This composite structure provides both the high fatty phase content needed for cutaneous lipid replenishment and the stability required to prevent demixing when combined with destabilizing materials like organic UV screens. The polymer network reinforces the emulsion structure while the surfactant maintains interfacial stability.
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 combination of gemini surfactant and semi-crystalline polymer results in emulsions that are stable, non-greasy, and pleasant to apply, maintaining homogeneity even with organic UV screens, addressing the issues of sensory properties and stability.
Implementation Method 1
using therein, by way of emulsifier, a particular gemini surfactant
Implementation Method 2
in combination with an effective amount of at least one semi-crystalline polymer which is solid at ambient temperature and which has a melting point of below 70° C., comprising a) a polymeric backbone and b) at least one crystallizable organic side chain and/or one crystallizable organic block
Data Source
AI summary
A cosmetic or dermatological compositions of oil-in-water emulsion type, including, in a physiologically acceptable medium, at least gemini surfactant of formula (I):in which R1 and R3 denote, independently of one another, an alkyl radical containing from 1 to 25 carbon atoms; R2 denotes a spacer consisting of a linear or branched alkylene chain containing from 1 to 12 carbon atoms; X and Y denote, independently of one another, a group —(C2H4O)a—(C3H6O)bZ; n ranges from 1 to 10, in combination with an effective amount of at least one semi-crystalline polymer which is solid at ambient temperature and which has a melting point below 70° C., said polymer having a number-average molecular mass greater than or equal to 2000, said emulsion having a proportion of fatty phase of greater than 10% by weight relative to the total weight of the composition and including more than 40% by weight of non-volatile oil(s) relative to the weight of the fatty phase.