| 摘要 |
PURPOSE:To restrict any reduction in the strength of a cord in practical travelling in the case of polyvinylalcohol synthetic fiber cord for reinforcing pneumatic tires by setting the strength of the cord so as to meet a specific relationship of a specific twist coefficient. CONSTITUTION:A pneumatic tire is provided with a polyvinylalcohol synthetic fiber (PVA fiber) cord reinforced belt 1 and a steel cord reinforced belt 2. In this case, filaments of the PVA fiber cord are bridged by a bridging material. When a specific twist coefficient of the PVA fiber cord is expressed by NT, the strength S of the PVA fiber cord taken out from a tire is set to meet the following relationship: S>=14.5-12 NT. Further, when the PVA fiber cord is melted in dimethylsulfoxide at temperature of 120 deg.C, insoluble matters are set at above 5 weight %. As a result, any reduction in the strength of the PVA fiber cord can be restricted even after paratical travelling. |
