UV-Resistant Cationic Polymers for Sunscreen Stability
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Solution Overview
Problem
Current sunscreen compositions face challenges in maintaining ultraviolet protection and rheological stability, leading to issues such as de-emulsification and settling, which affect their efficacy and stability.
Innovation Solution
The development of ultraviolet light-absorbing polymers, specifically polysiloxane and PEG/PPG copolymers with cationic functional groups, that help maintain suspensions and emulsions, improving the sun protection factor (SPF) and rheological stability of sunscreen compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sunscreen compositions are used, then ultraviolet protection is provided, but de-emulsification and settling occur affecting stability
Solution Approach 1:
The patent introduces polymers with both ultraviolet light-absorbing groups and cationic groups as intermediary substances. These polymers serve dual functions: absorbing UV radiation to protect skin/hair and providing cationic stabilization to prevent de-emulsification and settling of the sunscreen composition, thereby resolving the contradiction between UV protection and emulsion stability
Solution Approach 2:
The invention employs composite polymer structures that combine ultraviolet light-absorbing moieties (such as benzophenone, cinnamate, or avobenzone groups) with cationic functional groups (such as quaternary ammonium or tertiary sulfonium groups). This composite material simultaneously provides photoprotection and rheological stabilization, preventing both UV damage and composition degradation
2Reliability
If more ultraviolet light-absorbing compound is incorporated, then sun protection factor improves, but product complexity and formulation difficulty increase
Solution Approach 1:
The patent creates multifunctional polymers that simultaneously serve as UV filters, emulsion stabilizers, and rheology modifiers. By incorporating ultraviolet light-absorbing groups directly into the polymer backbone or as side chains along with cationic groups, a single ingredient performs multiple functions, improving SPF while reducing formulation complexity and the need for separate stabilizing agents
3Object-affected harmful factors
If ultraviolet light-absorbing materials are used, then UV protection is achieved, but interaction between ingredients reduces photostability
Solution Approach 1:
The invention uses composite polymer structures where ultraviolet light-absorbing groups are covalently bound to the polymer backbone. This molecular-level integration ensures that the UV-filtering components remain chemically associated with the stabilizing polymer matrix, preventing ingredient separation and maintaining photoprotective efficacy and photostability under UV exposure
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
These polymers enhance the stability and efficacy of sunscreen compositions by keeping ultraviolet light-absorbing components in solution, allowing for improved SPF with reduced usage and maintaining emulsion stability, thus providing better protection against UV radiation.
Implementation Method 1
Ultraviolet light-absorbing materials, such as p-aminobenzoic acid, are organic compounds with conjugated π-electron systems that absorb ultraviolet light and convert the absorbed energy into heat
Implementation Method 2
Quaternary amines adhere to hair fibers and may assist in retention of a polymer bound to an ultraviolet light-absorbing component
Data Source
AI summary
Polymers comprising at least one cationic functional group and at least one ultraviolet light-absorbing compound are disclosed herein. The polymers exhibit ultraviolet light-absorbing properties and may be used in sunscreen compositions for skin and/or hair.