PEG-8/SMDI COPOLYMER

What Is PEG-8/SMDI COPOLYMER?

A synthetic copolymer formed by reacting PEG-8 with saturated methylene diphenyl diisocyanate (SMDI). This polyurethane-type polymer functions as a film-forming agent in cosmetic products, creating a flexible, breathable, and water-resistant film on the skin or hair. It is used primarily in sunscreens (for water resistance), long-wear makeup, and water-resistant skincare products.

Key Skin Benefits

• + Water-resistant film — creates a breathable barrier that resists wash-off, useful in sunscreens and long-wear products
• + Flexible hold — provides light, non-stiff film formation on skin and hair
• + Improves product longevity — helps actives stay on skin longer

Pros

• + CIR-reviewed — polyurethane-type film formers considered safe in cosmetics
• + Non-comedogenic — forms a breathable, non-occlusive film
• + Effective at low concentrations — typically 0.5-3% for film-forming
• + Versatile — used in sunscreens, makeup, skincare, and hair products

Cons

• − Isocyanate precursor (SMDI) — fully reacted in final polymer but the chemistry raises concerns for some consumers
• − Fully synthetic — petroleum-derived, not natural
• − Limited biodegradability — persistent in the environment
• − May feel slightly tight or drying on some skin types at high concentrations
• − Limited independent safety studies on this specific copolymer

Specifications

Safety Ratings

Regional Regulatory Limits

Typical Usage % by Product Type

References

1. CIR (2017) — Safety Assessment of Polyurethane Ingredients as Used in Cosmetics.
2. CosIng (2025) — European Commission Cosmetic Ingredient Database. https://ec.europa.eu/growth/tools-databases/cosing/
3. EWG Skin Deep — Cosmetic Ingredient Database. https://www.ewg.org/skindeep/
4. FDA (2025) — Sunscreen Drug Products for OTC Human Use. https://www.fda.gov/