Biodegradable Resin Particles for Cosmetics with Controlled Morphology
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Solution Overview
Problem
Resin particles used in external preparations, such as cosmetics, often lack a small particle diameter and spherical shape, leading to poor spreadability and stability due to their porous surface, which affects their adhesion to the skin.
Innovation Solution
Biodegradable resin particles with a polyhydroxy alkanoate composition, specifically designed to have a volume average particle diameter of 2 to 50 μm, a BET specific surface area of 0.8 to 10 m2/g, and a linseed oil absorption of 50 to 300 ml/100 g, incorporating a Ca component in the range of 10 to 10,000 ppm, to enhance skin adhesion and spreadability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If resin particles are produced by milling methods (cryomilling), then biodegradable material is used, but the particles do not have a spherical shape or small particle diameter, resulting in poor spreadability on the skin
Solution Approach 1:
The invention changes the manufacturing parameters by controlling particle diameter within 2-50 μm, specific surface area within 0.8-10 m²/g, and oil absorption within 50-300 ml/100g. These parameter specifications transform the milling process output into spherical particles with improved spreadability while maintaining biodegradability
Solution Approach 2:
The invention explicitly targets spherical particle shape formation through controlled milling and classification processes. The spherical morphology is achieved by optimizing milling conditions and subsequent particle size distribution control, directly addressing the non-spherical defect of conventional milling methods
2Reliability
If resin particles are produced by solvent dissolution-precipitation methods, then relatively spherical shape is achieved, but the particles do not have a small particle diameter and have porous surfaces, resulting in brittleness and low stability
Solution Approach 1:
The invention specifies precise parameter ranges: particle diameter 2-50 μm, specific surface area 0.8-10 m²/g, and oil absorption 50-300 ml/100g. These controlled parameters prevent excessive porosity while maintaining spherical shape, thereby achieving both small particle diameter and high stability
Solution Approach 2:
The invention uses polyhydroxy alkanoate as the base biodegradable resin and incorporates calcium components (10-10,000 ppm) to strengthen the particle structure. This composite approach reduces brittleness caused by porous surfaces while maintaining the spherical shape and small particle diameter
3Stability of the object's composition
If resin particles have porous surfaces to increase surface area, then adhesion to skin may improve, but the particles become brittle and have low stability
Solution Approach 1:
The invention optimizes the specific surface area parameter within the range of 0.8-10 m²/g, which balances adhesion performance with structural integrity. This controlled surface area prevents excessive porosity that would cause brittleness while maintaining sufficient adhesion to skin
Solution Approach 2:
The incorporation of calcium components (10-10,000 ppm) into the polyhydroxy alkanoate matrix strengthens the particle structure. This reinforcement allows the particles to maintain higher surface area for adhesion without becoming brittle, thus resolving the contradiction between surface area and stability
Data Source
AI summary
Biodegradable resin particles including a polyhydroxy alkanoate. In the biodegradable resin particles, an amount of a Ca component present in the particles is 10 to 10,000 ppm, the biodegradable resin particles have a volume average particle diameter of 2 to 50 μm, the biodegradable resin particles have a BET specific surface area of 0.8 to 10 m2/g, and the biodegradable resin particles have a linseed oil absorption of 50 to 300 ml/100 g. The resin particles of the present invention can be suitably used by being included in an external preparation, such as a cosmetic or a quasi-drug.