From viewpoints of being eco-friendly and reducing cost while suppressing materials and waste to the extent possible, there has been known an open-style type disposable diaper which is manufactured by attaching a waist panel material to a rectangular absorbent body including an absorbent member while previously manufacturing the waist panel material having a fastening tape in a separate process. From a viewpoint of fit, it is preferable that the waist panel material is a stretchable member. Generally, the waist panel material is formed by utilizing a stretchable film. However, since a stretchable sheet is expensive, it is preferable to form the waist panel material by utilizing a so-called thread rubber which is a general elastic member. Here, in a case that a process to obtain a waist panel material using thread rubber and a process to obtain an open-style type disposable diaper as attaching the waist panel material to the absorbent body are continuously performed in sequence, a stretchable direction of the waist panel material formed by using the thread rubber generally becomes the same as the conveyance direction of the absorbent body to be a direction perpendicular to a stretchable direction of the waist panel material required for wearing an open-style type disposable diaper. Accordingly, in a case of manufacturing an open-style type disposable diaper by attaching the waist panel material formed by using thread rubber to the absorbent body in an inline process, the waist panel material formed by using thread rubber is required to be attached to the absorbent body after being rotated by 90°. Since an apparatus to rotate the waist panel material by 90° is required separately, equipment investment is increased.
As a method without using an apparatus to cause rotation of 90° as described above, for example, Patent Literature 1 and Patent Literature 2 disclose a stretchable sheet manufacturing method including a process of bonding a thread-shaped elastic body to a sheet in a state of being stretched while adhesive is applied to a permeable sheet moving in a length direction and the thread-shaped elastic body provided with tension is translated onto the adhesive applied face along the sheet face of the moving sheet toward the sheet moving direction in a zigzag state and a process of cutting the thread-shaped elastic body at both ends. Further, Patent Literature 1 also discloses a method to rearrange the zigzag thread-shaped elastic body to be parallel.
However, being different from a case of fixing the thread-shaped elastic body introduced along the sheet conveyance direction to the sheet, with the method to obtain a stretchable sheet by orienting the thread-shaped elastic body in a direction intersecting with the sheet conveyance direction as being wound around a pair of feeding belts and integrating the thread-shaped elastic body in the abovementioned state with the sheet as disclosed in Patent Literatures 1 and 2, stretch stress characteristics of sheets are more likely to be fluctuated in accordance with a manufacturing speed of stretchable sheets. For example, when the manufacturing speed becomes high, it becomes difficult to maintain stretch stress characteristics of manufactured sheets to be constant.
USPTO Backgrounds
USPTO Backgrounds