2011 年 77 巻 783 号 p. 4239-4253
Plastic film, formed as wound roll, is often stored, transported and heat-treated under the various temperatures which can be different from the winding temperature. Then the in-roll stress may vary over time due to thermal strain and viscoelastic property of the film. As a result, it could lead to wound roll defect such as slippage or wrinkling. Therefore, it is extremely important to theoretically estimate the in-roll stress in order to prevent the defect efficiently. In this study, a thermal-viscoelastic winding model is presented. On the winding model, creep function which is extended to consider dependence of stress/temperature on the viscoelastic property and entrained-air effect, is applied on viscoelastic component of thermal-viscoelastic mechanical model. From verification experiment on which a polypropylene film is used as a plastic film, the result indicates that the predicted values generally correspond to the experimental values on the radial stress. Additionally, relationship with the predicted time variations of the in-roll stress and the wound roll defect is showed.