Water-in-Oil Solid Cosmetic with Wax-Hectorite Oil Phase

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Solution Overview

Problem

Conventional water-in-oil emulsion solid cosmetics suffer from poor spreadability, stickiness, and reduced freshness due to powder aggregation and reduced oil absorption, especially at high temperatures, and lack long-lasting properties.

Innovation Solution

Incorporating a non-hydrophobized powder into the water phase and solidifying the oil phase with a wax and disteardimonium hectorite to enhance stability and spreadability, while maintaining a fresh texture and long-lasting performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a hydrophobized powder is dispersed into the oil phase and the oil phase is solidified with a solid wax, then the cosmetic achieves water resistance and efficient containment of emollient oil and ultraviolet absorber, but powder aggregation occurs due to adsorption of powder particles onto the wax, resulting in poor spreadability and reduced freshness

Engineering Contradiction:
Improvewater resistanceVSAvoidspreadability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent introduces a water phase as an intermediary medium to disperse the powder particles, preventing direct contact and aggregation between powder particles and wax. The water phase acts as a barrier that maintains powder dispersion while still allowing the oil phase to provide water resistance through the water-in-oil emulsion structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the cosmetic system into distinct water phase and oil phase compartments. By placing powder particles in the water phase rather than the oil phase, the system separates the functions of powder dispersion (in water phase) from water resistance (provided by oil phase emulsion structure), preventing unwanted interactions between powder and wax.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If a hydrophobized powder is used, then the powder can be dispersed in the oil phase, but the oil absorption ability of the powder is reduced, making it difficult to prevent makeup deterioration caused by sebum

Engineering Contradiction:
Improvedispersion stabilityVSAvoidoil absorption ability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The water phase serves as an intermediary that allows non-hydrophobized powder to be dispersed without requiring hydrophobization treatment. This maintains the natural oil absorption properties of the powder while achieving stable dispersion through the water continuum.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of modifying the powder surface to be hydrophobic for oil phase dispersion, the patent inverts the approach by dispersing the powder in the water phase of a water-in-oil emulsion. This maintains the powder's natural properties while achieving the desired dispersion and oil absorption functionality.

Inventive Principle:
Principle #13The other way round (Inversion)

3Strength

If a large amount of cyclic silicone oil is incorporated to achieve smooth texture, then the cosmetic feels soft, but spreadability and refreshing feeling are reduced

Engineering Contradiction:
Improvetexture smoothnessVSAvoidspreadability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent modifies the silicone oil composition by limiting cyclic silicone oil content and introducing linear silicone oil with specific viscosity ranges. This parameter change maintains the desired smooth texture while improving spreadability by reducing the overly viscous and occlusive properties of high cyclic silicone oil content.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite silicone oil system combining linear silicone oil and limited cyclic silicone oil, along with other emollients and esters. This composite approach balances the smoothness provided by cyclic silicone oil with the spreadability enhancement from linear silicone oil and other lighter emollients.

Inventive Principle:
Principle #40Composite materials

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 solution provides a cosmetic with improved spreadability, fresh texture, enhanced oil absorption, and stability at high temperatures, offering a long-lasting and refreshing user experience.

Implementation Method 1

solidifying the oil phase with a wax and disteardimonium hectorite

Methodology Applied
Scientific EffectSolidification: Freezing

Implementation Method 2

solidifying the oil phase with a wax

Methodology Applied
Scientific EffectSolidification: Freezing

Implementation Method 3

enhanced oil absorption

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP3331493B1Water-in-oil emulsion solid cosmetic
Publication Date: 2022.11.30 SHISEIDO CO LTD

AI summary

The object of the present invention is to provide a water-in-oil emulsion solid cosmetic that is further improved in terms of an excellent feeling in use (good spreadability and fresh feeling (texture)) obtained by incorporating a powder in a water phase, and that also has sufficient covering ability, stability even at high temperature, and long-lasting property. The present invention provides a water-in-oil emulsion solid cosmetic comprising an external oil phase comprising a liquid oil thickened or solidified with (A) wax and (B) disteardimonium hectorite, and an internal water phase comprising (C) an internal phase powder dispersed in an aqueous medium.