Science
Mechanism of Action
This polymer operates by creating a breathable, flexible film on the skin's surface, acting as an effective film former and surface modifier. It can also function as a molecular 'bridge' in hydrogel systems, enhancing mechanical flexibility and promoting robust adhesion without irritation, while its film-forming capacity potentially supports tissue regeneration by absorbing exudates.
Research
Clinical Evidence
Low confidenceN/A
Transparency
Dusting Analysis
The Formula
Formulation
Stability
Polyurethane-4 is susceptible to hydrolysis under extreme pH conditions; specifically, strong acids (pH 1-3) and strong alkaline environments can degrade its urethane and urea linkages, with urea linkages showing faster degradation. Polyether-based polyurethanes generally exhibit superior hydrolytic stability compared to polyester variants. Formulators must also consider that raw material solutions may contain additional sensitizing chemicals.
Conflicts
- strong acids (e.g., 37% Hydrochloric Acid, 98% Sulfuric Acid, 48% Hydrofluoric Acid)
- strong bases (e.g., 50% Sodium Hydroxide)
- ketones (e.g., Acetone, Cyclohexanone, Methyl Ethyl Ketone)
- dichloromethane
- diethylamine
Safety
Safety Profile
The CIR Expert Panel evaluated 66 polyurethane ingredients, including Polyurethane-4, concluding their safety for cosmetic use provided final products are non-sensitizing and devoid of residual isocyanates or monomers. However, formulators are advised to mitigate risks from potentially sensitizing constituents, such as methylisothiazolinone, which might be present in the supplied ingredient solutions.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Polyurethane-4 is a versatile film-forming polymer, safely applicable across all skin types, contributing to formulation aesthetics and stability without known irritancy or comedogenicity concerns.
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References
Sources