Methods for controlling the mixing process of processing rubber

1. A method for processing a rubber, comprising:

a mastication stage comprising the steps of;

allowing a material to exist in a kneading chamber equipped with a stirring rotor whose rotational speed being automatically controllable by a control section, the kneading chamber being enclosed and capable of measuring and outputting an interior temperature, and the material containing a rubber component; and

setting a control time and a target temperature on the control section wherein the target temperature is set to a temperature lower than 100° C.:

a first kneading stage comprising the steps of;

allowing the rubber component to exist in the kneading chamber;

setting a control time and a target temperature on the control section; and

maintaining the rubber component at the actual temperature almost equal to the target temperature over an extended period of time: and

a second kneading stage comprising the steps of;

adding a vulcanizing agent to the rubber component in the kneading chamber; and

setting a control time and a target temperature on the control section:

wherein stirring inside the kneading chamber while automatically controlling the rotational speed by a PID control configured to attempt to match the actual temperature with the target temperature until expiration of a control time being set, based on the information regarding the actual temperature and information regarding a target temperature being set, during and after completion of each stage.

2. The method for processing a rubber according to claim 1 , wherein the material contains a natural rubber or a rubber mixture containing 50% or more of a natural rubber.

3. The method for processing a rubber according to claim 2 , wherein during the mastication stage the target temperature is set to a temperature lower than a lower limit temperature at and above with the natural rubber is scorched.

4. The method for processing a rubber according to claim 1 , wherein the material contains a rubber component, silica and a silane coupling agent.

5. The method for processing a rubber according to claim 4 , wherein during the first kneading stage the target temperature is lower than a lower limit temperature at which the rubber component undergoes gelation, and higher than a lower limit temperature at which a coupling reaction of silica with a silane coupling agent occurs.

6. The method for processing a rubber according to claim 5 , wherein the rubber component contains a modified styrene-butadiene rubber modified with an amine and an alkoxysilane, and the silane coupling agent contains bis(3-triethoxysilylpropyl)disulfide or a blocked mercaptosilane.

7. The method for processing a rubber according to claim 4 , wherein during the first kneading stage the rubber component is maintained at the actual temperature almost equal to the target temperature over an extended period of time to permit a sufficient coupling reaction of the silane coupling agent in the kneading chamber.

8. The method for processing a rubber according to claim 1 , wherein during the second kneading stage the target temperature is a temperature lower than a lower limit temperature at which the rubber component initiates cross-linking.

9. The method for processing a rubber according to claim 8 , wherein the target temperature is a temperature lower than 120° C.

10. The method for processing a rubber according to claim 9 , wherein the target temperature is a temperature lower than 110° C.