Low-Viscosity O/W Emulsions with Nanoscale Droplets

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Solution Overview

Problem

Existing oil-in-water emulsions for cosmetics face challenges in achieving very small oil droplet sizes, homogeneous distribution, low viscosity, storage stability under fluctuating temperatures, and ease of dilution without gelling, while maintaining these properties during long-term storage and use in cosmetics applications such as impregnating textiles and paper.

Innovation Solution

The development of low-viscosity O/W emulsions with oil droplet diameters between 0.01 and 0.3 μm, using a specific emulsifier mixture of ethoxylated hydrogenated castor oils with a mass ratio of 1 to 15 mol and 20 to 80 mol of ethylene oxide, and a polarity index of 15 to 55 mN/m, which can be produced using the phase inversion process at temperatures below 90°C, ensuring stability and sprayability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If conventional emulsifiers are used to produce O/W emulsions, then oil droplet sizes can be reduced below 500 nm, but viscosity becomes too high for good sprayability

Engineering Contradiction:
Improveoil droplet sizeVSAvoidviscosity
Core Design Contradiction:
Length of moving objectVSShape

Solution Approach 1:

The patent changes the chemical composition parameters of the emulsifier system by combining specific non-ionic emulsifiers (fatty alcohol ethoxylates) with anionic emulsifiers (fatty acid soaps or alkyl sulfonates). This compositional parameter change enables achieving both small droplet sizes (0.01-0.3 μm) and low viscosity (<300 mPas) simultaneously, resolving the contradiction between droplet size reduction and viscosity control.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If high phase inversion temperatures (up to 95°C) are used to produce stable PIT emulsions, then droplet size distribution becomes more homogeneous, but storage stability deteriorates due to water content

Engineering Contradiction:
Improvehomogeneous oil droplet size distributionVSAvoidstorage stability
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent changes the process parameter of phase inversion temperature to an optimal range of 70-90°C, avoiding excessively high temperatures. Combined with the dual emulsifier system, this parameter change achieves homogeneous droplet distribution while maintaining storage stability, preventing the emulsion from breaking down during storage.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite emulsifier system combining non-ionic emulsifiers (for droplet formation and homogeneity) with anionic emulsifiers (for stability and prevention of coalescence). This composite approach enables achieving both homogeneous droplet distribution and storage stability without requiring excessively high phase inversion temperatures.

Inventive Principle:
Principle #40Composite materials

3Stability of the object's composition

If emulsions are stored in cold conditions, then viscosity increases and sprayability deteriorates, but storage stability should be maintained

Engineering Contradiction:
Improvestorage stability in coldVSAvoidviscosity at cold temperature
Core Design Contradiction:
Stability of the object's compositionVSShape

Solution Approach 1:

The patent changes the emulsifier composition parameters by incorporating anionic emulsifiers with specific HLB values (12-18) that provide cold-temperature stability. This compositional parameter change prevents excessive viscosity increase during cold storage while maintaining emulsion stability and sprayability.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If conventional emulsifier mixtures are used, then emulsions can be produced, but they gel or crystallize at high temperatures during storage

Engineering Contradiction:
Improveemulsion productionVSAvoidresistance to gelling and crystallization
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical composition parameters of the emulsifier system by selecting specific non-ionic emulsifiers (fatty alcohol ethoxylates with 2-10 ethylene oxide units) combined with anionic emulsifiers. This parameter change prevents gelation and crystallization at high temperatures while maintaining ease of production.

Inventive Principle:
Principle #35Parameter changes

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 resulting emulsions exhibit excellent storage stability, maintain low viscosity, and can be easily diluted, providing a homogeneous distribution of oil droplets, making them suitable for various cosmetic applications, including impregnating textiles and paper without gelling, even at cold temperatures.

Implementation Method 1

heating selected O/W emulsions with special non-ionic emulsifiers above the phase inversion temperature and then cooling. This PIT process assumes O/W emulsions with large oil droplets, which when heated undergo a phase reversal into a W/O emulsion, which is reversible

Methodology Applied
Scientific EffectPhase inversion: Phase Change

Data Source

PatentEP3288645B1Low-viscosity oil-in-water emulsions for cosmetic applications
Publication Date: 2019.10.16 BASF SE

AI summary

The invention relates to the field of oil-in-water emulsions for cosmetics, and to low-viscosity O/W emulsions with very small-sized oil droplets, to a method for the production of same, and to the use of same for impregnating textiles and paper for cosmetics.