| 摘要 |
PROBLEM TO BE SOLVED: To eliminate defects such as a joint removal, blister and crevice, by a method wherein after cutting a long-shape extruded rubber member, containing a foaming agent, by a specified length, the long-shape extruded rubber member is formed into a ring-shape by bonding both ends, and then, the extruded rubber member is vulcanized. SOLUTION: When an expanded tube for tire is manufactured, first, a rubber composition containing a foaming agent, is extruded from a mouthpiece having a circular opening, of an extruder, and a long-shape extruded rubber member 10 of which the cross section being rectangular to the longitudinal direction is circular, is obtained. Then, the extruded rubber member 10 is cut by a specified length by a cutter, etc. Then, cut surfaces 15 on both ends are bonded to each other, and the extruded rubber member 10 is formed into a doughnut ring-body 14. Then, the doughnut ring-body 14 is vulcanized using a mold which is constituted of an upper die and a lower die. For the vulcanizing method, it is performed by dividing into two steps of a primary vulcanization and a secondary vulcanization, and the vulcanization is performed in such a manner that a temperature reduction of the doughnut ring-body 14 from the completion of the first vulcanizing process to the start of the second vulcanizing process may be within 60 deg.C. |
