Mixing rubber material placed during the "self-sulfurization" of the main reasons?

(1) The use of too much sulfurizing agent and accelerator.

(2) The loading capacity is too large, the temperature of the refining machine is too high, and the cooling of the film is not enough.

(3 ) or too early to add sulfur, material dispersion is not uniform resulting in the accelerator and sulfur local concentration.

(4) improper parking, that is, the parking place temperature is too high, air circulation is not.