A mixing module includes two inlets, an integrator, and a valve member. The integrator has two chambers each having a near end and a far end, and the valve member is movable between two positions. One of the inlets is connected to the near end of one of the chambers and the other inlet is connected to the near end of the other chamber when the valve is in one position. When the valve is in the other position, one of the inlets is disconnected from the chambers and the near ends of the chambers are connected.

A mixing module includes two inlets, an integrator, and a valve member. The integrator has two chambers each having a near end and a far end, and the valve member is movable between two positions. One of the inlets is connected to the near end of one of the chambers and the other inlet is connected to the near end of the other chamber when the valve is in one position. When the valve is in the other position, one of the inlets is disconnected from the chambers and the near ends of the chambers are connected.

An injecting machine includes an injection cylinder, a plunger, a plunger moving mechanism, and a mixing mechanism. The plunger is reciprocally received in the injection cylinder for moving between an advanced position and a retracted position, with the injecting a liquid mixture of two different liquid materials as the plunger moves to the advanced position. The plunger moving mechanism causes the plunger to move between the advanced position and the retracted position. The mixing mechanism is disposed on the injection cylinder for mixing the two different liquid materials together to feed the liquid mixture into the injection cylinder. The plunger includes a front portion having a helical groove formed on an outer circumferential surface thereof to allow the liquid mixture fed from the mixing mechanism to pass through the helical groove for collecting in a forward space formed forward of the front portion of the plunger.

A rubber composition manufacturing method comprises an operation in which at least rubber, silica, and silane coupling agent are kneaded in an internal kneader at not less than a temperature lower limit for a coupling reaction between the silica and the silane coupling agent to proceed. For at least a portion of time during which that operation is being carried out, a compressed gas is delivered to the kneading chamber while the ram is in a nonpressing state.