| abstract |
Hygroscopic fiber is low in volume and resilience, and has been a problem to develop in batting. Although some techniques for improving the bulkiness are known, the initial volumetric property remains assured, and the bulkiness tends to decrease due to moisture absorption, repeated use, and aging. The present invention has been devised in view of such a phenomenon of the prior art, and an object thereof is to provide a hygroscopic granular cotton and a batting containing the granular cotton, both of which are hygroscopic and sustained volume. The present invention is a granulated cotton containing a surface layer portion made of a polymer having a crosslinked structure and a carboxyl group and a hygroscopic fiber made of a central portion made of an acrylonitrile-based polymer, and exhibits a degree of expansion of the volume after removing the load with respect to the volume under a constant load. It is a hygroscopic granular cotton which has a volume expansion rate of 15% or more, and a moisture absorption rate of 4% or more in an environment of 20 ° C and 65% relative humidity. |