Sunblock Composition Bicontinuous Microemulsion UV Protection
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Solution Overview
Problem
Conventional sunscreen compositions face challenges in achieving high ultraviolet protection and stability while maintaining a refreshing, dewy texture, as well as uniform coating and absorption, due to limitations in the type and quantity of ultraviolet absorbents that can be used in emulsified systems.
Innovation Solution
A sunscreen composition utilizing a bicontinuous microemulsion phase, comprising specific surfactants, water, an oil component, and ultraviolet absorbents, is formulated to achieve a thermodynamically stable and optically isotropic solution that enhances ultraviolet protection and skin absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a large quantity of oil soluble ultraviolet absorbent is blended into oil-in-water emulsified composition, then ultraviolet protection ability is improved, but the emulsion stability deteriorates and texture becomes sticky
Solution Approach 1:
The patent changes the physical state parameter of the system from conventional emulsion to microemulsion phase. By adjusting the surfactant type and concentration, along with oil and water ratios, the system transitions to a microemulsion state that can stably accommodate high concentrations of oil soluble ultraviolet absorbents without phase separation or stickiness, thus resolving the contradiction between UV protection and emulsion stability.
Solution Approach 2:
The patent uses a composite surfactant system comprising both ionic and nonionic surfactants. This composite approach creates a microemulsion phase that combines the benefits of both surfactant types, enabling high oil soluble UV absorbent loading while maintaining system stability and avoiding the sticky texture associated with conventional emulsions.
2Object-affected harmful factors
If water soluble ultraviolet absorbent is added to maintain low oil soluble absorbent ratio, then ultraviolet protection ability is improved, but salt concentration increases and emulsification stability deteriorates
Solution Approach 1:
The patent changes the system parameter from conventional emulsion to microemulsion phase by adjusting surfactant composition and ratios. This phase transition eliminates the need for high salt concentrations to stabilize the system, allowing water soluble UV absorbents to be incorporated without compromising emulsification stability, thus resolving the contradiction between UV protection and emulsion stability.
3Object-affected harmful factors
If oil component quantity is increased in water-in-oil emulsified composition, then ultraviolet protection ability is improved, but texture becomes sticky and oiliness increases
Solution Approach 1:
The patent changes the system from conventional water-in-oil emulsion to microemulsion phase. This phase transition allows high oil component concentrations to be achieved while maintaining low viscosity and excellent spreadability, eliminating the sticky and oily texture problems associated with conventional water-in-oil emulsions.
4Object-affected harmful factors
If highly polar ultraviolet absorbent is dissolved in oil phase of water-in-oil emulsion, then ultraviolet protection ability is improved, but long term stability deteriorates due to separation and aggregation
Solution Approach 1:
The patent changes the system parameter from conventional emulsion to microemulsion phase. In this microemulsion state, highly polar ultraviolet absorbents can be dissolved in the oil phase without undergoing separation and aggregation over time, as the microemulsion structure provides thermodynamic stability that prevents phase separation, thus resolving the contradiction between UV protection and long term stability.
Data Source
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AI summary
The present invention provides a sunscreen composition comprising (a) a surfactant, (b) water, (c) an oil component, and (d) a water soluble ultraviolet absorbent and/or oil soluble ultraviolet absorbent that is in the bicontinuous microemulsion phase at 25°C. The object of the present invention is to obtain a sunscreen composition that is superior in terms of the ultraviolet protection ability and the tactile sensation during use. Furthermore, its object is to provide a sunscreen composition composed of a transparent bicontinuous microemulsion phase that spreads well when applied on the skin, is superior in terms of the coating film uniformity and absorption into the skin.