Hydrophobized Titanium Oxide Emulsion Stability

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Solution Overview

Problem

Existing oil-in-water type emulsified cosmetics struggle to achieve stable dispersion and emulsion stability of hydrophobized titanium oxides with average particle sizes greater than 0.1 µm, which are necessary for effective skin beautification and UV protection, while also maintaining a refreshing feel and preventing color streaking.

Innovation Solution

A cosmetic formulation combining hydrophobized titanium oxide with an average particle size of at least 0.1 µm, sugar ester, liquid higher fatty acid, higher alcohol, non-ionic surfactant, and water, where the hydrophobized titanium oxide is dispersed in the oil phase, forming a lamellar bimolecular film for enhanced stability and dispersibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fine-particle titanium oxide with average particle size of at least 0.1 µm is used for skin beautification and UV protection, then the covering ability and UV protection effect are improved, but the dispersibility and emulsion stability deteriorate due to strong cohesive forces

Engineering Contradiction:
ImproveUV protection effect and skin beautificationVSAvoidemulsion stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

A surfactant is introduced as an intermediary substance to mediate between the hydrophobized titanium oxide particles and the aqueous phase. The surfactant adsorbs onto the particle surfaces and provides steric or electrostatic repulsion, preventing aggregation and improving both dispersibility and emulsion stability while maintaining the UV protection and skin beautification effects.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite system combining hydrophobized titanium oxide particles with specific surfactants and oils. This composite approach allows the titanium oxide to maintain its particle size for effective UV protection and skin beautification, while the surfactant-oil complex provides the necessary stability and dispersibility in the emulsion formulation.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If mechanical dispersion is applied to fine-particle titanium oxide, then the powder can be blended into the product, but the emulsion stability remains insufficient and agglomeration occurs over time

Engineering Contradiction:
Improvedispersion processabilityVSAvoidemulsion stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The titanium oxide particles are pre-treated with hydrophobizing agents before incorporation into the emulsion. This preliminary surface modification reduces cohesive forces between particles, making them easier to disperse mechanically and preventing subsequent agglomeration, thereby improving both manufacturability and long-term emulsion stability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Surfactants are used as intermediaries that bridge the hydrophobized particles and the aqueous continuous phase. These surfactants adsorb onto particle surfaces during mixing, providing ongoing steric or electrostatic stabilization that prevents agglomeration over time while allowing effective mechanical dispersion during manufacturing.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If larger particle size titanium oxide is used, then the cohesive force decreases and dispersion becomes easier, but the emulsion stability is still insufficient with hydrophobized titanium oxides

Engineering Contradiction:
Improvedispersion easeVSAvoidemulsion stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

Even with larger particle sizes that reduce cohesive forces, surfactants are introduced as intermediaries to provide additional steric or electrostatic repulsion. This ensures that the particles remain individually dispersed and stable in the emulsion matrix, preventing aggregation that would otherwise occur over time despite the reduced inherent cohesion.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes multiple parameters including particle size distribution, surfactant concentration, HLB value, and oil phase composition. By carefully adjusting these parameters, the formulation achieves both easy dispersion of larger particles and long-term emulsion stability, with the surfactant playing a critical role in maintaining particle separation.

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 formulation provides improved emulsion stability, prevents color streaking, and effectively beautifies the skin by maintaining the natural appearance and concealing abilities of the titanium oxide, while ensuring a refreshing user experience.

Implementation Method 1

a non-ionic surfactant, other than the (B) component; (F) water; and (G) an oil component, wherein the (A) component is dispersed in the oil phase

Methodology Applied
Scientific EffectSurfactant: Surfactant

Implementation Method 2

an oil-in-water type emulsified cosmetic characterized by comprising: (A) 1 to 20 mass% of a hydrophobized titanium oxide having an average particle size of at least 0.1 μm

Methodology Applied
Scientific EffectEmulsion: Emulsion

Implementation Method 3

as UV protectants by physically scattering and absorbing UV rays at the particle surface

Methodology Applied
Scientific EffectScattering: Scattering

Implementation Method 4

as UV protectants by physically scattering and absorbing UV rays at the particle surface

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 5

due to having a high refractive index, as covering agents for adjusting skin tone such as dullness or redness of the face

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3127531B1Oil-in-water type emulsified cosmetic
Publication Date: 2020.02.19 SHISEIDO CO LTD

AI summary

The present application provides an oil-in-water type emulsified cosmetic which has the effect of beautifying the appearance of skin and also excels in emulsion stability. The oil-in-water type emulsified cosmetic according to the present invention is characterized by comprising (A) 1 to 20 mass% of a hydrophobized titanium oxide having an average particle size of at least 0.1 µm; (B) a sugar ester having a carboxyl group within the structure; (C) a liquid higher fatty acid; (D) a higher alcohol; (E) a non-ionic surfactant; (F) water; and (G) an oil component.