"Moreover, the polymers must allow sufficient migration of the active compound towards the surface of the shaped article. [0101] Other polyvinyl resins include polyvinyl halides such as polyvinyl chloride, polyvinyl chloride/vinyl acetate and polyvinyl fluoride; polyacrylate and polymethacrylate esters, such as polymethyl acrylate and polymethyl methacrylate; and polyvinylbenzenes, such as polystyr" . . . .