  We prove regularity estimates for time derivatives of a large class of
nonlinear parabolic partial differential systems. This includes the
instationary (symmetric) p-Laplace system and models for non Newtonien fluids
of powerlaw or Carreau type. By the use of special weak different quotients,
adapted to the variational structure we bound fractional derivatives of $u_t$
in time and space direction.
  Although the estimates presented here are valid under very general
assumptions they are a novelty even for the parabolic p-Laplace equation.
