Acrylic Copolymer Sunscreen Emulsion Stability
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Solution Overview
Problem
Existing oil-in-water emulsion sunscreens face challenges in achieving high ultraviolet protection while maintaining emulsion stability and avoiding stickiness or powder squeakiness, as high amounts of ultraviolet protectants can degrade the cosmetic feel.
Innovation Solution
Combining an acrylic copolymer with phosphoric acid groups, a hydrophobically treated ultraviolet scattering agent, and a water phase thickener in the oil-in-water emulsion sunscreen, where the ultraviolet scattering agent is dispersed in the oil phase, to enhance ultraviolet protection power and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If high amounts of ultraviolet absorbing agents are blended to achieve high ultraviolet protection effects, then ultraviolet protection power is improved, but the amount of oils must be increased which causes stickiness and degrades the feeling in use
Solution Approach 1:
The patent changes the chemical parameters of the ultraviolet absorbing agent by using a polymer compound with specific functional groups (carboxyl, hydroxyl, or amine groups) and controlled molecular weight. This allows the agent to be effectively dissolved in the aqueous phase without requiring excessive oils, thus maintaining good feeling in use while achieving high ultraviolet protection power.
Solution Approach 2:
The patent uses a composite approach by combining the polymer compound ultraviolet absorbing agent with other components (surfactants, thickeners, and optional ultraviolet scattering agents) to create a synergistic formulation. This composite system achieves high protection power without the need for large amounts of oils that would cause stickiness.
2Object-affected harmful factors
If high amounts of ultraviolet scattering agents are blended to achieve high ultraviolet protection effects, then ultraviolet protection power is improved, but the fluidity within the coating film is lowered causing powder squeakiness and degraded feeling in use
Solution Approach 1:
The patent modifies the parameters of the ultraviolet scattering agent by applying hydrophobic surface treatment. This treatment changes the surface properties to improve compatibility with the oil phase and prevent excessive aggregation, thereby maintaining coating film fluidity and preventing powder squeakiness while still providing high ultraviolet protection power.
3Object-affected harmful factors
If high-polarity ultraviolet absorbing agents are blended to improve ultraviolet protection, then ultraviolet protection power is improved, but emulsion stability becomes difficult to maintain
Solution Approach 1:
The patent uses surfactants as intermediaries to bridge the high-polarity ultraviolet absorbing agent and the oil phase. The surfactants reduce interfacial tension and improve compatibility, allowing high-polarity agents to be effectively incorporated into the emulsion system without compromising emulsion stability.
Solution Approach 2:
The patent adjusts the molecular structure and polarity parameters of the polymer compound ultraviolet absorbing agent by selecting specific functional groups and molecular weights. This parameter optimization allows the agent to be effectively dissolved in the aqueous phase with appropriate surfactants, maintaining both high ultraviolet protection power and emulsion stability.
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
This combination significantly increases ultraviolet protection power and maintains excellent emulsion stability, allowing for the inclusion of high-polarity ultraviolet absorbing agents, thereby improving the cosmetic's performance without compromising feel.
Implementation Method 1
hydrophobically treated ultraviolet scattering agent
Implementation Method 2
acrylic copolymer having phosphoric acid groups
Implementation Method 3
water phase thickener
Implementation Method 4
ultraviolet scattering agent
Data Source
AI summary
An objective of the invention is to increase the ultraviolet protection power of an ultraviolet scattering agent, thereby providing an oil-in-water emulsion sunscreen cosmetic that can achieve high ultraviolet protection power and that has excellent emulsion stability. The sunscreen cosmetic according to the present invention comprises (A) an acrylic copolymer having phosphoric acid groups; (B) a hydrophobically treated ultraviolet scattering agent; and (C) 0.3% by mass or more of a water phase thickener; wherein the ultraviolet scattering agent is dispersed in an oil phase.