By the Vinogradov-Korobov estimate we have
$\left|\frac{\zeta^{(k)}}{\zeta} (1+it)\right| \le c_k Y^k(t)$ where $Y(t)= \ln^{2/3} (|t|+3) (\ln\ln (|t|+3))^{1//3}$ for some $c_k$.
I search the value of $c_k$ without the Riemann hypothesis or other hypothesis in the litterature.
Can you help me ?