Typical alkyl methacrylates that can be used have 1-8 carbon atoms in the alkyl group and are for example methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, 2-ethyl hexyl methacrylate and the like.