Castor Oil/Ipdi Copolymer

Castor Oil/IPDI Copolymer is a film-forming polymer (castor oil modified with isophorone diisocyanate) typically used at low percentages to improve texture and wear; once reacted, it behaves as an inert emollient/resin with low irritancy in routine patch testing. The main safety consideration is rare sensitivity in highly reactive individuals to residual monomers/impurities, but at typical cosmetic concentrations it is generally well tolerated and not intrinsically irritating, supporting a very gentle score. Safety Notes: Castor Oil/IPDI Copolymer is most often used as an oil-gellant/viscosity builder and film-forming structurant in anhydrous leave-on systems (lip oils/glosses, balms, stick products) and appears at low levels (~0.1–1%) when used only to boost payoff, gloss, and stability. In consumer lip oils, glosses, and high-structure balms/sticks it is commonly in the ~5–15% range, and the strongest OTC products that rely on it as a primary structuring resin/gellant can reach ~20–25% in anhydrous formats; rinse-off products, when used, are typically at the low end due to limited benefit and build-up concerns.