Sprayable Sunscreen Composition Using Pickering Emulsion
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Solution Overview
Problem
Existing sunscreen compositions in spray form often have a greasy feeling and appear white on the skin due to high amounts of hydrophobic UV filters, which are not aesthetically pleasing and do not provide effective photoprotection.
Innovation Solution
A translucent or transparent sprayable sunscreen composition is developed using an oil-in-water Pickering emulsion, stabilized by hydrophobic particles like ethyl cellulose, with a dispersed hydrophobic phase containing hydrophobic UV-screening agents and a continuous aqueous phase including C1-C4 alcohols, without the use of surfactants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high amounts of hydrophobic UV filters are used in conventional sprayable sunscreen products, then UV-screening ability is improved, but the product presents a greasy feeling and white color on the skin
Solution Approach 1:
The invention divides the UV filter system into two distinct segments: hydrophilic UV filters (water-soluble) and hydrophobic UV filters (oil-soluble). The hydrophilic UV filters are dissolved in the aqueous phase, while the hydrophobic UV filters are incorporated into the dispersed oil phase as droplets. This segmentation allows each type to contribute to UV protection without the drawbacks of the other, eliminating the greasy feeling and white color while maintaining effective UV-screening ability.
Solution Approach 2:
The invention introduces an intermediary emulsion system consisting of a continuous aqueous phase containing hydrophilic UV filters and a dispersed oil phase containing hydrophobic UV filters. The emulsion acts as a mediator that combines both types of UV filters into a single sprayable composition, allowing them to work together synergistically while the aqueous continuous phase prevents the greasy feeling and white coloration that would result from using only hydrophobic UV filters.
2Reliability
If conventional emulsion systems with hydrophobic UV filters are used, then UV protection is provided, but the mist appears white and gives an unpleasant heavy feeling on the skin
Solution Approach 1:
The invention changes the physical and chemical parameters of the UV filter system by selecting hydrophilic UV filters with appropriate solubility characteristics and molecular weights that allow them to dissolve in the aqueous phase. This parameter change enables the formulation of a transparent, non-greasy sprayable composition that maintains effective UV protection while significantly improving cosmetic pleasantness and eliminating the white appearance.
3Ease of operation
If sprayable form is used for sunscreen composition, then ease of use is improved, but obtaining high protection index becomes difficult
Solution Approach 1:
The invention merges the advantages of both hydrophilic and hydrophobic UV filters into a single sprayable composition. By combining hydrophilic UV filters in the aqueous phase with hydrophobic UV filters in the dispersed oil phase, the formulation achieves a high protection index suitable for sprayable application, overcoming the limitation that conventional sprayable sunscreens struggle to provide adequate UV protection.
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 composition provides a good sunblocking effect with sufficient SPF and PPD values, offering effective UV protection while maintaining a pleasant, non-greasy feel and a clear appearance on the skin.
Implementation Method 1
said emulsion is a pickering emulsion comprising no surfactant
Implementation Method 2
at least one hydrophobic particle selected from the group consisting of hydrophobic silicas, hydrophobic cellulose, starch, talc, silicone resin powders, hollow hemispherical silicone particles, polyamide powders, hydrophobic pigments
Implementation Method 3
a dispersed hydrophobic phase comprising at least one hydrophobic UV-screening agent
Implementation Method 4
at least one hydrophilic UV-screening agent
Implementation Method 5
a continuous aqueous phase comprising from 0.1% to 20% by weight, relative to the total weight of the composition, of at least one C 1 -C 4 alcohol with at least one hydroxyl group
Data Source
AI summary
A composition in form of an oil-in-water emulsion comprises a) a dispersed hydrophobic phase comprising at least one hydrophobic UV-screening agent and optionally at least one oil, said oil being selected from the group consisting of silicone oils, hydrocarbonated oils, and any mixture thereof; b) a continuous aqueous phase comprising from 0.1% to 20% by weight, relative to the total weight of the composition, of at least one C1-C4 alcohol with at least one hydroxyl group, linear or branched, saturated or unsaturated; and c) at least one hydrophobic particle selected from the group consisting of hydrophobic silicas, hydrophobic cellulose, starch, talc, silicone resin powders, hollow hemispherical silicone particles, polyamide powders, hydrophobic pigments, and any mixture thereof; d) at least one gellan gum or a derivative thereof, and e) at least one hydrophilic UV-screening agent.