Resin Particle Stabilized Oil-in-Water Skin Preparation

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Solution Overview

Problem

Oil-in-water external skin preparations face challenges in achieving stability and rough-surface correction while maintaining good texture, particularly when blending powders like silica, which can lead to decreased stability and poor texture when used in large amounts.

Innovation Solution

Incorporating resin particles from specific vinyl-type monomers and emulsifying with surfactants such as polyoxyethylene hydrogenated castor oil, silicone-type surfactants, and sulfonic acid-type surfactants in the aqueous phase, along with an oil phase and a surfactant blend, to enhance emulsion stability and rough-surface correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If silica powder is blended in the aqueous phase to provide texture and rough-surface correction, then the preparation can deliver protection and absorption functions, but the stability decreases when a large amount is blended

Engineering Contradiction:
Improveemulsion stabilityVSAvoidamount of powder blended
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes the chemical composition parameters by replacing conventional silica powder with specifically designed resin particles having controlled molecular structure, particle size distribution, and surface properties. This parameter change allows achieving the same texture and correction functions with improved emulsion stability even at higher blending amounts.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite resin particles formed by polymerizing vinyl-type monomers with specific functional groups. These composite particles combine the benefits of powder dispersion (for texture and correction) with enhanced compatibility to the aqueous phase and oil phase, thereby maintaining stability at higher concentrations.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If resin particles are used as a mattifying agent, then the preparation can provide texture improvement, but the stability often decreased when a large amount was blended

Engineering Contradiction:
Improvetexture qualityVSAvoidemulsion stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent optimizes the molecular weight, functional group content, and particle size parameters of the resin particles. By controlling these parameters within specific ranges, the resin particles provide excellent texture and mattifying effects while maintaining emulsion stability even at higher blending amounts up to 20% or more.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If powder is blended to provide rough-surface correction effect, then the preparation can improve skin texture, but the stability decreases when used in large amounts

Engineering Contradiction:
Improverough-surface correction effectVSAvoidemulsion stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces surfactants as intermediary substances that mediate between the resin particles and the oil-water interface. These surfactants adsorb onto the resin particle surfaces, providing steric stabilization and preventing aggregation, thereby maintaining both the rough-surface correction effect and emulsion stability at higher powder concentrations.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach results in an oil-in-water external skin preparation with improved stability, texture, and rough-surface correction effects, even when powders are blended in higher quantities, by optimizing surfactant adsorption and emulsion stability.

Implementation Method 1

an oil-in-water external skin preparation which comprises (a) an aqueous phase containing resin particles, (b) an oil phase, and (c) a surfactant

Methodology Applied
Scientific EffectEmulsion: Emulsion

Implementation Method 2

a surfactant comprising one or more selected from polyoxyethylene hydrogenated castor oil, silicone-type surfactants, and sulfonic acid-type surfactants

Methodology Applied
Scientific EffectSurfactant: Surfactant

Implementation Method 3

by blending resin particles in the aqueous phase and emulsifying with a specific surfactant

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP2630948B1External oil-in-water-type skin preparation
Publication Date: 2018.08.22 SHISEIDO CO LTD
  • EP2630948B1 patent drawingFigure 1
  • EP2630948B1 patent drawingFigure 2
  • EP2630948B1 patent drawing

AI summary

The present invention provides an oil-in-water external skin preparation that has an excellent stability, excellent rough-surface correction effect, and excellent texture. The oil-in-water external skin preparation of the present invention is characterized by comprising (a) an aqueous phase containing resin particles obtained from 100 parts by weight of a vinyl-type monomer and 0.1 to 20 parts by weight of a monomer represented by the below general formula (I), (b) an oil phase, and (c) a surfactant comprising one or more selected from polyoxyethylene hydrogenated castor oil, silicone-type surfactants, and sulfonic acid-type surfactants, in the amount of 0.01 to 5 % by mass of the total amount of the external skin preparation and 30 % by mass or more of the total amount of surfactants. (In the above formula, R represents a hydrogen atom or a methyl group, 1 represents 1 to 50, and m represents 1 to 50.)