(Meth)acrylate polymer for improving the viscosity index, consisting of the following compositions: 45.0% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate and 30.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate, M w = 69800 g/mol; 35.0% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate and 40.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate, M w = 77500 g/mol; 15.0% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate and 60.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate, M w = 77800 g/mol; 41.5% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate, 30.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate and 3.5% by weight of 3-dimethylaminopropyl methacrylate, M w = 69800 g/mol; 41.5% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate, 30.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate and 3.5% by weight of 2-dimethylaminoethyl methacrylate, M w = 61200 g/mol; 41.5% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate, 30.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate and 3.5% by weight of 2-(4-morpholinyl)ethyl methacrylate, M w = 60400 g/mol; 41.5% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate, 30.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate and 3.5% by weight of 2-(3-oxazolidinyl)ethyl methacrylate, M w = 78200 g/mol; 41.5% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate and 33.5% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate, M w = 79000 g/mol; 35.0% by weight of dodecyl-pentadecyl methacrylate, 5.0% by weight of methyl methacrylate and 60.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate, M w = 83900 g/mol; 65.0% by weight of dodecyl-pentadecyl methacrylate, 5.0% by weight of methyl methacrylate and 30.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate, M w = 67000 g/mol; and 53.3% by weight of dodecyl-pentadecyl methacrylate, 24.2% by weight of methyl methacrylate, 19.4% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate and 3.1% by weight of N-vinyl-2-pyrrolidone. 45.0% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate and 30.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate, M w = 69800 g/mol; 35.0% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate and 40.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate, M w = 77500 g/mol; 15.0% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate and 60.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate, M w = 77800 g/mol; 41.5% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate, 30.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate and 3.5% by weight of 3-dimethylaminopropyl methacrylate, M w = 69800 g/mol; 41.5% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate, 30.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate and 3.5% by weight of 2-dimethylaminoethyl methacrylate, M w = 61200 g/mol; 41.5% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate, 30.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate and 3.5% by weight of 2-(4-morpholinyl)ethyl methacrylate, M w = 60400 g/mol; 41.5% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate, 30.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate and 3.5% by weight of 2-(3-oxazolidinyl)ethyl methacrylate, M w = 78200 g/mol; 41.5% by weight of dodecyl-pentadecyl methacrylate, 25.0% by weight of methyl methacrylate and 33.5% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate, M w = 79000 g/mol; 35.0% by weight of dodecyl-pentadecyl methacrylate, 5.0% by weight of methyl methacrylate and 60.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate, M w = 83900 g/mol; 65.0% by weight of dodecyl-pentadecyl methacrylate, 5.0% by weight of methyl methacrylate and 30.0% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate, M w = 67000 g/mol; and 53.3% by weight of dodecyl-pentadecyl methacrylate, 24.2% by weight of methyl methacrylate, 19.4% by weight of 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate and 3.1% by weight of N-vinyl-2-pyrrolidone.