Phthalic Anhydride …

Phthalic anhydride/benzoic acid/trimethylolpropane copolymer is a synthetic polymer—a long-chain molecule made by chemically combining three different building blocks. It is film-forming, meaning it creates a thin, continuous layer when applied to skin.This ingredient is used primarily in cosmetic formulations to improve texture, longevity, and appearance. It helps products adhere to the skin and can give a smoother, more refined finish to the complexion.

The polymer works by depositing a flexible film across the skin's surface. This film is thin enough to let the skin breathe and shed dead cells naturally, but structured enough to even out the skin's topography visually and help other ingredients in the formula stay in place.Because it is synthetic and inert, it does not penetrate the skin or alter its biological function—it works mechanically, not chemically.

This ingredient is typically found in foundations, primers, and colour cosmetics rather than skincare serums or moisturisers. If using a product containing this polymer, apply according to the product instructions. It can be used daily as part of a cosmetic routine. Remove thoroughly at the end of the day with your usual cleanser to avoid buildup.

This ingredient is generally well-tolerated and considered safe for cosmetic use. Allergic contact dermatitis is rare, though some individuals with very sensitive skin may experience mild irritation if products are left on for extended periods without removal.