Science
Mechanism of Action
Composed of organic units joined by carbamate (urethane) links, POLYURETHANE-8 works by forming a flexible and tenacious film upon application to the skin. This film provides physical continuity to cosmetic formulations, improves their adhesion, and offers a protective barrier. Its plasticizing properties further contribute to the ductility and comfort of the formed film.
Research
Clinical Evidence
Low confidenceN/A
Transparency
Dusting Analysis
The Formula
Formulation
Stability
Polyurethane stability is influenced by factors such as pH and temperature. Waterborne polyurethane dispersions (PUDs) are particularly sensitive to pH differentials when combined with other emulsions, potentially leading to 'shocking' (grit formation or gellation) if pH values are not appropriately matched. General chemical resistance varies with the concentration of chemicals, temperature, and duration of contact.
Conflicts
- Significant pH mismatches with other emulsion components, such as acrylic emulsions, can result in formulation instability, characterized by grit formation or gellation.
- Formulators should be cautious when polyurethanes are supplied in solutions containing sensitizers (e.g., methylisothiazolinone), avoiding the combination of multiple such solutions to prevent unintended high concentrations of sensitizers.
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) Expert Panel assessed the safety of 66 polyurethane ingredients, including Polyurethane-8, concluding they are safe in current cosmetic practices and concentrations, provided they are formulated to be non-sensitizing. The panel determined there would be no detectable residual isocyanate or other monomers in these ingredients. While specific maximum concentrations for Polyurethane-8 were not provided, other polyurethanes, such as Polyurethane-1, were found non-sensitizing in mascaras at concentrations up to 30%, and Polyurethane-21 demonstrated low irritation potential at 21% solids. No SCCS status was found. The FDA regulates polyurethane resins in other applications, such as food-contact adhesives and medical devices, noting mild local inflammatory responses in animal studies for medical devices, which is a different context than cosmetic skin application.
Your Skin
Skin Compatibility
Our Assessment
Verdict
POLYURETHANE-8 is a valuable polymeric ingredient for enhancing product adhesion, film integrity, and skin protection, recognized as safe for cosmetic applications when properly formulated.
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References
Sources