| 摘要 |
PURPOSE:To prevent the generation of the breakage of a block by applying internal pressure to a tire to vulcanize the same and foaming unvulcanized tread rubber. CONSTITUTION:Tread rubber 14 is removed to obtain a base tire 12 and unvulcanized tread rubber 14 having a foaming agent added thereto is bonded to the base tire. The base tire having the tread rubber 14 bonded thereto is received in a mold and a vulcanizing bladder is raised in temp. When the mold is raised in temp. and a heating medium of predetermined pressure is injected in the vulcanizing bladder, the tread rubber 14 of the base tire 12 is foamed and vulcanized to be bonded to the base tire 12. The base tire satisfying the relation of 0%<={(B-BO)/B}X100<=0.25% between the diameter (BO) of the outermost belt of the tire before the application of internal pressure (2.0kg/cm<2>) and the diameter (B) of the outermost belt at the time of vulcanizing molding in a mold is used and a vulcanizing condition is set so that the temp. of the heating medium in the vulcanizing bladder is 125-150 deg.C and the temp. of the mold is 140-170 deg.C. |
