Methyl Methacrylate/Trimethoxysilylpropyl Methacrylate Crosspolymer is a copolymer of methyl methacrylate and trimethoxysilylpropyl methacrylate which is crosslinked with triethoxysilylpropylmethoxycinnamide. See Reported Ingredient Functions-The Cosmetic Drug Distinction, in Regulatory and Ingredient Use Information, Volume I, Part A.