Poly [ [ 6 -[( 1 , 1 , 3 , 3 - tetramethylbutyl ) amino ] - 1 , 3 , 5 - triazine - 2 , 4 - diyl ] [ ( 2 , 2 , 6 , 6 - tetramethyl - 4 - piperidinyl ) imino ] - 1 , 6 - hexanediyl [ ( 2 , 2 , 6 , 6 - tetramethyl - 4 - piperidinyl ) imino ] ] )