In-Shower Emulsion Viscosity Transition for Skin Active Retention

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Solution Overview

Problem

Existing skin conditioning compositions for use during showering or bathing often rinse off easily, leaving little benefit on the skin due to high initial viscosities that make them difficult to apply.

Innovation Solution

A water-in-oil high internal phase emulsion with a low initial viscosity (<6500 cps) that thickens during application and in the presence of water, ensuring active agents remain on the skin, while being easy to spread and apply, comprising at least 73% water and including steric and depletion stabilizers, emulsifiers, and skin benefit agents like dihydroxyacetone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the composition is formulated with high initial viscosity (≥ 10,000 cps) to prevent rinsing off, then the active agent remains on the skin, but the composition becomes difficult to apply

Engineering Contradiction:
Improveretention of active agent on skinVSAvoidease of application
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The composition exhibits dynamic viscosity changes based on environmental conditions. It maintains low viscosity at application temperature for easy spreading, then transitions to high viscosity at skin temperature to prevent rinsing off. This dynamic property allows the same composition to satisfy both ease of application and active agent retention requirements

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent utilizes temperature-dependent viscosity parameter changes. The composition is applied as a cool liquid with low viscosity, then undergoes a phase transition upon contact with warmer skin, increasing viscosity significantly. This parameter change enables the composition to be easily applied yet remain effectively on the skin

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the composition is formulated with low initial viscosity to improve spreadability, then the composition is easy to apply, but the active agent rinses off easily

Engineering Contradiction:
ImprovespreadabilityVSAvoidretention of active agent on skin
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The composition dynamically adjusts its viscosity based on temperature. During application, the cool composition maintains low viscosity for excellent spreadability. After application, as the composition warms to skin temperature, it undergoes a viscosity transition to a thick, adherent state that prevents rinsing off, thus ensuring active agent retention

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The composition undergoes a phase transition from a fluid state at application temperature to a semi-solid or gel-like state at skin temperature. This phase change is driven by the temperature difference between the applied composition and the skin, resulting in increased viscosity and improved active agent retention while maintaining ease of application

Inventive Principle:
Principle #36Phase transitions

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 effectively retains active agents on the skin during showering or bathing, providing a pleasant, silky feel and maintaining at least 18% of the active on the skin post-application, as confirmed by HPLC analysis, with improved spreadability and reduced rinsing.

Implementation Method 1

a water-in-oil and high internal phase emulsion that may be formulated with an active or skin benefit agent within the water phase. The composition can be used to deliver the active while showering or bathing, and unexpectedly, the composition thickens during application and in the presence of water

Methodology Applied
Scientific EffectEmulsion thickening: Emulsion

Implementation Method 2

comprising at least 73% water and including steric and depletion stabilizers, emulsifiers, and skin benefit agents

Methodology Applied
Scientific EffectSteric stabilization:

Implementation Method 3

comprising at least 73% water and including steric and depletion stabilizers, emulsifiers, and skin benefit agents

Methodology Applied
Scientific EffectDepletion stabilization:

Data Source

PatentEP2257264B1In-shower and bath compositions
Publication Date: 2017.05.17 UNILEVER PLC

AI summary

In-the-shower or in-the-bath compositions having a high internal phase emulsion are described. The high internal phase emulsion is a water-in-oil emulsion where active is present in the water phase. The compositions have an initial viscosity which is low and they are suitable to thicken when being applied in the presence of water.