Oil-in-Water Sunscreen Emulsion Stability and UV Protection
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Solution Overview
Problem
Existing sunscreen cosmetics face challenges in enhancing ultraviolet protection while maintaining the usability and stability of the base agent, as increasing ultraviolet absorbent content often compromises these aspects.
Innovation Solution
An oil-in-water emulsified sunscreen cosmetic formulation incorporating specific surfactants, ultraviolet absorbents, and higher alcohols, along with β-alanyl-L-histidine, to achieve improved ultraviolet protection, stability, and sensory experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ultraviolet absorbent content is increased to increase ultraviolet protection, then ultraviolet protection is improved, but usability and stability of the base agent become poor
Solution Approach 1:
The patent divides ultraviolet protection into multiple functional components: oil-soluble ultraviolet absorbents (ethylhexyl methoxycinnamate, octocrylene), water-soluble ultraviolet absorbents (phenylbenzimidazolesulfonic acid), and physical UV filters ( titanium dioxide, zinc oxide). This segmentation allows each component to contribute to UV protection without requiring excessive concentrations that would compromise usability or stability.
Solution Approach 2:
The patent creates a composite sunscreen system combining multiple surfactants (POE stearic ester, sorbitan tristearate, glyceryl stearate), multiple ultraviolet absorbents (both oil-soluble and water-soluble types), and physical filters. This composite approach provides comprehensive UV protection while maintaining base agent stability and usability through synergistic effects of the combined ingredients.
2Reliability
If the ultraviolet absorbent content is increased to increase ultraviolet protection, then ultraviolet protection is improved, but stability of the base agent becomes poor
Solution Approach 1:
The patent segments ultraviolet protection mechanisms into chemical absorbents (both oil-soluble and water-soluble) and physical filters. This allows the base agent composition to remain stable while achieving high UV protection through multiple non-interfering mechanisms that don't compromise each other's stability.
Solution Approach 2:
The patent uses specific surfactants (POE stearic ester with POE mole number 20-120, sorbitan tristearate, glyceryl stearate with HLB 5-8) as intermediaries to stabilize the emulsion system. These surfactants act as mediators between the oil-soluble and water-soluble ultraviolet absorbents, preventing phase separation and maintaining base agent stability even at high UV protectant concentrations.
3Reliability
If carnosine is added to provide antioxidant benefits, then antioxidant protection is improved, but pH of the base agent increases
Solution Approach 1:
The patent carefully controls the concentration of carnosine (β-alanyl-L-histidine) within specific ranges (0.1-4.5 wt%) and adjusts the pH of the base agent to maintain it below 8. This parameter control allows the antioxidant benefits of carnosine to be achieved while preventing excessive pH increase that would compromise product stability and skin compatibility.
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 formulation effectively increases ultraviolet protection, enhances the stability and usability of the base agent, and prevents pH increase, ensuring a stable and effective sunscreen cosmetic.
Implementation Method 1
an oil-in-water emulsified sunscreen cosmetic comprising (a) a phospholipid, (b) a non-ionic surfactant and/or anionic surfactant
Implementation Method 2
containing an oil soluble ultraviolet absorbent and a water soluble ultraviolet absorbent
Data Source
AI summary
The object of the present invention is to provide an oil-in-water emulsified sunscreen cosmetic that is superior in stability and the sensation during use. This object is achieved by providing an oil-in-water emulsified sunscreen cosmetic that satisfies all of the following conditions (A), (B), (C), (D), and (E): (A) Containing the following three types of surfactants (A-1)-(A-3) in the amount of 1-6 wt% of the total amount of the cosmetic (A-1) A POE stearic ester having a POE mole number of 20-120 (A-2) Sorbitan tristearate (A-3) Glyceryl stearate having a HLB of 5-8 (B) Containing the following oil soluble ultraviolet absorbent, which is solid at room temperature, in the amount of 0.01-5 wt% of the total amount of the cosmetic Bis-ethylhexyloxyphenolmethoxyphenyltriazine and/or tert-butylmethoxybenzoylmethane (C) Containing the following oil soluble ultraviolet absorbent, which is liquid at room temperature, in the amount of 1-14 wt% of the total amount of the cosmetic Ethylhexyl methoxycinnamate and/or octocrylene (D) Containing the following water soluble ultraviolet absorbent in the amount of 0.1-5 wt% of the total amount of the cosmetic Phenylbenzimidazolesulfonic acid (E) Containing higher alcohol having 14-24 carbon atoms