METHOD FOR PRODUCING RUBBER MATERIAL BY KNEADING RUBBER RAW MATERIAL AND COMPOUNDING AGENT, AND OPEN-ROLL MACHINE

PROBLEM TO BE SOLVED: To provide a method for production of a rubber material advantageous in continuously obtaining the rubber material in which a compounding agent is uniformly mixed even in a case of the rubber material having low tackiness, and to provide an open-roll machine.SOLUTION: When a rubber material 24A having low tackiness, leaked out from a gap between the rolls 12 and 14 and hardly winding around a front roll 12 becomes a swell away from the outer peripheral surface of the roll 12, the swollen portion of the rubber material 24A is pressed onto the outer peripheral surface of the roll 12, and a cutting line 30 is entered into the rubber material by the cutting part 3204 of a cutting line-forming member 32, that is, the inside air of the swollen rubber material 24A is let out by the cutting line, and the rubber material is wound onto the outer peripheral surface of the front roll 12. Besides, accompanying the rotation of the front roll 12, the rubber material is sequentially folded every cutting line 30 along the extending direction of the cutting line 30 to be effectively and more advantageously mixed in a bank 24.