Nanocrystalline Cellulose Sunscreen Composition for High SPF and Transparency
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Solution Overview
Problem
Existing sunscreen compositions with high SPF often compromise on cosmetic properties such as fluidity, homogeneity, and transparency due to the use of high amounts of organic or mineral UV screening agents, leading to a greasy or whitening effect on the skin.
Innovation Solution
Incorporating functionalized nanocrystalline cellulose, specifically carboxylated nanocrystalline cellulose, into sunscreen compositions to improve photoprotective properties while maintaining fluidity and transparency, and preventing the whitening effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large amounts of organic UV screening agents are added to achieve high SPF, then photoprotective properties are improved, but cosmetic qualities deteriorate causing greasy and tacky feeling
Solution Approach 1:
The patent introduces a specific organic UV filter (ethylhexyl triazone) as an intermediary substance that provides high photoprotective efficiency at low concentrations, thereby maintaining cosmetic qualities while achieving high SPF. This mediator allows the formulation to balance between protection and comfort.
2Reliability
If mineral sunscreens are used to achieve high SPF without greasy feeling, then photoprotective properties are improved, but whitening effect and viscosity increase
Solution Approach 1:
The patent changes the particle size parameter of mineral UV filters to nanoscale dimensions (50-200 nm), which fundamentally alters their optical properties. This parameter change reduces the refractive index effect, minimizing whitening while maintaining high SPF protection.
Solution Approach 2:
The patent creates a composite formulation combining multiple UV filters (organic ethylhexyl triazone with mineral titanium dioxide and zinc oxide) in specific ratios. This composite approach leverages the strengths of each component while compensating for their individual weaknesses, achieving high SPF with minimal whitening.
3Reliability
If concentration of mineral sunscreen is increased to improve photoprotection, then SPF is improved, but viscosity of composition rises
Solution Approach 1:
The patent changes the size parameter of mineral particles to nanoscale, which significantly reduces their impact on viscosity. Nanoparticles have smaller hydrodynamic radius and interact differently with the continuous phase, allowing higher concentrations without excessive thickening.
Solution Approach 2:
The patent applies surface treatment to mineral particles, modifying their local surface properties to improve dispersibility and reduce aggregation. This local modification prevents particle clustering that would otherwise increase viscosity.
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 use of carboxylated nanocrystalline cellulose in sunscreen compositions achieves high SPF without thickening the composition, maintaining transparency, and ensuring low whitening, resulting in a more comfortable and aesthetically pleasing skin application.
Implementation Method 1
The wavelengths from 280 to 400 nm pass through the ozone layer. Between 280 and 320 nm the rays are known as UV-B, whereas UV-A rays relate to the wavelengths between 320 and 400 nm.
Implementation Method 2
Incorporating functionalized nanocrystalline cellulose, specifically carboxylated nanocrystalline cellulose, into sunscreen compositions to improve photoprotective properties while maintaining fluidity and transparency
Implementation Method 3
Mineral sunscreens such as titanium dioxide or zinc oxide are well appreciated because they allow to efficiently reaching a high SPF
Implementation Method 4
Mineral sunscreens are characterized by a high refractive index, which produces a whitening effect on the skin during application
Data Source
AI summary
The present invention is directed to a sunscreen composition comprising, in a physiologically acceptable medium, (i) at least one sunscreen agent, and (ii) nanocrystalline cellulose.