Semi-Quantitative Evaluation of Heat Conduction of Paper Yarn and Cotton Yarn along Transverse Direction Using Thermo-sensitive Cholesteric Liquid Crystal Ink

: Fabrics woven with paper yarns show the higher cool touch feeling rather than conventional cotton yarn fabrics. We evaluated semi-quantitatively the transverse heat conduction of a single paper yarn to elucidate its high cool touch feeling and discussed the origin of the high heat conduction on the context of the inner structure of the yarn comparing with the cotton yarn. Thermo-sensitive inks show chromatic changes depending on temperature and we applied the ink on the single yarn as a thermo-indicator. The time depending temperature of the single paper yarn after contact on a heated metal plate showed a faster increase than that of the cotton yarns indicating the higher transverse heat conduction of the paper yarn. The observations of the microstructure of the yarns were investigated by Scanning electron microscope (SEM). It was inferred that the less anisotropy of the fiber orientation and the tight packing of the fibers in the paper yarn should be the structural origin of the higher transverse heat conduction of the paper yarn giving rise to the higher cool touch feeling.