Selenium Disulfide Superfine Powder Dispersion Stability
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Solution Overview
Problem
Existing selenium disulfide lotion products face challenges due to particle size issues, where large particles lead to delamination and small particles increase the risk of skin toxicity, and high glycerol content complicates the formulation of stable and effective products.
Innovation Solution
A new superfine powder of selenium disulfide with a particle size range of 1-50 µm and a D90 of 1.0-15.0 µm is developed, prepared by grinding selenium disulfide with glycerin, bentonite, titanium dioxide, and water in a specific mass ratio, which reduces glycerol content and improves particle distribution uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the particle size of selenium disulfide is reduced to improve dispersion uniformity, then the risk of skin toxicity increases due to higher probability of passing through the skin barrier
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size distribution parameters (D10, D50, D90) within specific ranges. The D50 is controlled at 3-20 μm and D90 at 7-40 μm, which optimizes the balance between dispersion uniformity and skin safety. This parameter optimization resolves the contradiction by finding the optimal particle size window that achieves good dispersion without excessive skin penetration.
Solution Approach 2:
The patent implements feedback control through particle size distribution measurement and adjustment. The preparation process includes measuring the particle size distribution and adjusting the grinding parameters to achieve the target D50 and D90 values. This feedback mechanism ensures that the particle size remains within the safe and effective range, preventing both aggregation and excessive fineness that would cause toxicity.
2Object-affected harmful factors
If the particle size of selenium disulfide is increased to reduce skin toxicity, then the lotion becomes prone to delamination and instability
Solution Approach 1:
The patent resolves this contradiction by changing the particle size distribution parameters to a specific range where D50 is 3-20 μm and D90 is 7-40 μm. This parameter optimization ensures particles are fine enough to remain suspended and dispersed uniformly in the lotion matrix, preventing delamination, while not being so fine as to penetrate the skin barrier excessively and cause toxicity.
3Manufacturing precision
If glycerol content is increased to improve dispersion of selenium disulfide, then the formulation flexibility is reduced and water-in-oil emulsion matrix cannot be formulated
Solution Approach 1:
The patent extracts the dependency on high glycerol content by achieving good dispersion through optimized particle size control instead. By controlling D50 at 3-20 μm and D90 at 7-40 μm, the selenium disulfide achieves uniform dispersion without requiring excessive glycerol (reducing to 5-20%). This extraction of the glycerol dependency restores formulation flexibility, enabling water-in-oil emulsion matrices and other formulation types that were previously incompatible with high glycerol requirements.
Solution Approach 2:
The optimized particle size distribution serves multiple functions simultaneously: it ensures uniform dispersion in the lotion matrix, maintains suspension stability, enables formulation flexibility including water-in-oil emulsions, and prevents skin toxicity. This multi-functionality resolves the contradiction by making the particle size control a universal solution that addresses dispersion without sacrificing formulation versatility.
4Ease of manufacture
If the particle size range is widened to include more particles, then the manufacturing is easier, but the particle distribution uniformity deteriorates
Solution Approach 1:
The patent applies parameter changes by defining specific ranges for particle size distribution parameters: D10 at 1-10 μm, D50 at 3-20 μm, and D90 at 7-40 μm. These parameter specifications balance manufacturability with uniformity. The ranges are wide enough to accommodate normal manufacturing variations but narrow enough to ensure consistent performance and uniform distribution in the final product.
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 new superfine powder enhances the stability, safety, and effectiveness of selenium disulfide lotion products by ensuring uniform dispersion and suspension, reducing the risk of delamination, and maintaining a stable concentration of selenium disulfide.
Implementation Method 1
The particle size of the superfine powder of selenium disulfide is (1.0-50.0) μm, and its particle size distribution with D90 is (1.0-15.0) μm
Data Source
Figure 1~3
AI summary
A new superfine powder of selenium disulfide with a particle size in the range of 1-50 µm and the particle size distribution with D90 of (1.0-15.0) µm, and its application in lotion products, are provided in the present invention. Compared with the prior art, the superfine powder of selenium disulfide in the present invention is beneficial to the preparation of the selenium disulfide lotion product and the improvement of the quality of the selenium disulfide lotion product.