A compound having formula (I) wherein R1 and R2 independently represent C1-C6 alkyl; R3 is C1-C6 alkyl; R4 is C1-C18 alkyl or C4-C18 heteroalkyl; m is zero, one, two or three; n is one, two or three; and j, k, p, q, r and s independently are zero, one or two; provided that at least one of j, k, p, q, r and s is not zero.
化合物的
化学式为(I),其中R1和R2分别代表C1-C6烷基;R3为C1-C6烷基;R4为C1-C18烷基或C4-C18杂烷基;m为零、一、二或三;n为一、二或三;j、k、p、q、r和s独立地为零、一或二;但至少有一个j、k、p、q、r和s不为零。