Method for forming stratified rubber article with variable cure rate

A method of forming a tread comprising two or more layers of rubber, the method comprising the steps of:

• extruding a rubber compound through a first extruder and a first gear pump;
• extruding an accelerant through a second extruder and a second gear pump and then into the first extruder for mixing the rubber compound with the accelerant, and then applying one or more first strips of a rubber mixture having a first cure rate from the output of the first gear pump directly onto a tire building machine;
• adjusting the amount of accelerant to obtain a second cure rate different than said first cure rate, and then applying one or more second strips of rubber mixture having a second cure rate directly onto the tire building machine, wherein one of the cure rates is faster than the other cure rate.