| 摘要 |
PURPOSE:To realize low noise level by forming an elastic substance used for a roll with a surfacial layer having high hardness, low dynamic magnifying rate and low loss coefficient and adding a vibration cutoff layer having high loss coefficient as an inner layer. CONSTITUTION:A rubber-like elastic substance used for a roll has a surfacial layer having the modulus of tensile elasticity of 250kg/cm<2> or more at 5% elongation, the ratio of 4 or less between the modulus of dynamic storage elasticity (100Hz, 0.3% distortion) and the modulus of tensile elasticity and its physical property indicating 0.3 or less of loss coefficient. This thermoplastic elastomer is 3mm or more thick. The intermediate layer has 30kg/cm<2>-120kg/cm<2> of modulus of tensile elasticity at 5% elongation, the ratio of 3 or less between the modulus of dynamic storage elasticity and the modulus of tensile elasticity at 5% elongation and its physical property indicating 0.07-0.25 of loss coefficient at 0.3% elongation. In the case of a 2-tier structure, if the surfacial layer is 3mm or less, its function to repulse energy as a surfacial layer is insufficient. Further in the case of a 2- or 3-tier structure, if the loss coefficient of the inner layer is 0.35 or less, the difference between said value and the loss coefficient of the surfacial layer is small, thus allowing no satisfactory vibration reduction effect to be obtained. |
