Cellulose Ether Spherical Microparticles via W/O Emulsion Coagulation
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Solution Overview
Problem
Existing methods for producing spherical microparticles from natural cellulose ethers using carbon disulfide as a solvent are environmentally harmful, and the resulting particles have poor sphericity and surface smoothness, leading to inadequate tactile sensation and texture in cosmetic compositions.
Innovation Solution
A method using a W/O type emulsion of low-substituted cellulose ether, prepared with environmentally friendly materials, followed by precipitation coagulation, to produce spherical microparticles with specific particle size, sphericity, and surface smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spray-drying is used to rapidly evaporate water from low-substituted cellulose ether dispersion solution, then production efficiency is improved, but particle shrinkage occurs resulting in poor sphericity and surface smoothness
Solution Approach 1:
The invention changes the physical parameters of the system by using a W/O emulsion configuration where cellulose ether is dispersed in oil phase with water as continuous phase, then undergoes precipitation coagulation. This parameter change allows particles to form and solidify without the rapid evaporation stress of spray-drying, eliminating particle shrinkage while maintaining high production efficiency through the coagulation process.
Solution Approach 2:
The invention utilizes phase transition from liquid emulsion to solid microparticles through precipitation coagulation. The W/O emulsion undergoes phase separation where the dispersed phase coagulates to form spherical microparticles with smooth surfaces, avoiding the mechanical stress and rapid evaporation that cause shrinkage in spray-drying methods.
2Ease of manufacture
If carbon disulfide is used as solvent in viscose solution production, then cellulose spherical microparticles can be produced, but environmental pollution is caused
Solution Approach 1:
The invention extracts and removes the harmful carbon disulfide solvent from the production process entirely. Instead of using carbon disulfide to dissolve cellulose and form viscose solution, the method uses water-based or environmentally benign solvent systems, eliminating the source of environmental pollution while maintaining the ability to produce cellulose spherical microparticles through alternative mechanisms like emulsion coagulation.
Solution Approach 2:
The invention changes the chemical parameters of the production system by replacing carbon disulfide with environmentally friendly solvents or water-based systems. This parameter change eliminates the harmful environmental effects associated with carbon disulfide while preserving the core functionality of producing spherical cellulose microparticles through modified production pathways.
3Quantity of substance
If low-substituted cellulose ether spherical microparticle is added in small amount, then cosmetic composition simplicity is improved, but adequate tactile sensation may be difficult to achieve
Solution Approach 1:
The invention changes the physical parameters of the microparticles themselves - achieving higher sphericity (0.75-1.0) and surface smoothness (75-100%) through the W/O emulsion coagulation method. These parameter improvements in particle morphology enhance the tactile sensation and texture of the cosmetic composition, allowing adequate sensory performance even at lower concentrations of 0.01-20% by mass.
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 resulting low-substituted cellulose ether spherical microparticles provide a pleasant tactile sensation and improved moisture retention in cosmetic compositions, even at low concentrations.
Implementation Method 1
subjecting the W/O type emulsion to a precipitation coagulation treatment
Data Source
AI summary
The objective of the present invention is to provide a low-substituted cellulose ether spherical microparticle that can contribute to improvement of tactile sensation of a cosmetic composition used, regardless of the use or non-use of carbon disulfide. The above objective is solved by a low-substituted cellulose ether spherical microparticle having an average particle size (D50) of primary particles on a volume basis by a dry laser diffraction method of 1 µm to 30 µm, a sphericity of 0.75 to 1.0, and a surface smoothness of 75% to 100%, and the like.