Three, multi-stage mixing method:
Generally, the two-stage mixing method is called multi-stage mixing method. Features: short mixing time each time, lower mixing temperature, more uniform carbon black dispersion, higher rubber quality, suitable for more carbon black and less rubber. Formula, such as radial tire tread rubber formula.
 
Fourth, the reverse order mixing method is also called reverse order or reverse order mixing method,
Inverse kneading method: A method in which other compounding agents other than the vulcanizing agent and the accelerator are first put into the mixer, and then the raw rubber is mixed for kneading. Commonly used for polymers with limited self-adhesion, such as EPDM. This process is also often used when the polymer content is low (15% -25%).
The main advantages of the inverse mixing method are improved dispersibility and shortened mixing time, which is suitable for mixing with poor raw rubber viscosity and high filling compound rubber.
The disadvantage is that higher power is required in the initial stage of mixing, which sometimes causes the mixer to stop, followed by poor dispersion. It is worth noting that the reinforcing filler cannot be dispersed well with this reverse order mixing. If fine carbon black particles are used, the compound can be traditionally mixed or later refueled.
The adding order of the reverse mixing method is: first add all the dry compounding agents "including various small materials (except accelerators, antioxidants), reinforcing fillers" → then add all liquid compounding agents (liquid softener, Process oil, etc. → Finally add raw rubber (including various synthetic rubber, plastic rubber, reclaimed rubber, master rubber) → the top pin drops to start mixing → mixing ends
The feeding sequence of this kneading method is exactly the opposite of that of the ordinary warming method. The operation is to add all the compounding agents to the mixing chamber at one time and then add the raw rubber. It is also possible to add 1/2 of the oil and all compounding agents, put the raw rubber into the mix, and then add the remaining poise in 2 to 3 times in 2 minutes, and then refining and debinding. This method can shorten the mixing time, and is especially suitable for the mixing of butadiene rubber and ethylene-propylene rubber with large filling amounts.