Sen'i Gakkaishi
Online ISSN : 1884-2259
Print ISSN : 0037-9875
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Volume 64, Issue 7
Displaying 1-12 of 12 articles from this issue
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  • Effect of Materials and Weaving Properties on UV Protection Efficiency of Apparel White Fabrics - Evaluation by Transmittance, Reflectance, Porosity and UPF -
    Masako Sasaki, Eiji Mishima, Yoshimasa Kagami, Syu Takeshita, Miyuki S ...
    2008 Volume 64 Issue 7 Pages 163-170
    Published: July 10, 2008
    Released on J-STAGE: August 10, 2008
    DOIhttps://doi.org/10.2115/fiber.64.163
    JOURNAL FREE ACCESS
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    The ultraviolet radiation (UV) protection efficiency of apparel white fabrics of cotton, nylon and polyester was investigated. The UV protection efficiency depended significantly on the transmittance of their polymer materials. For the cotton and polyester fabrics, the estimated UV protection efficiency showed a strong dependence on the weaving properties such as the type of weave, density of warp and weft, thickness, weight, fabric porosity and surface characteristics. Moreover, ultraviolet protection factor (UPF) of the white fabrics was evaluated for the UV-A and UV-B radiation. The results are summarized as follows: 1) The UV transmittance in the 250-400nm regions of white fabrics of cotton, nylon and polyester depends on that of their material polymers. 2) Polyester is defined as UV-B protective material, because it does not transmit wavelengths shorter than 310nm, and also the reflectance of polyester is lower than that of cotton and nylon in this wavelength regions. 3) The UV protection efficiency of white fabrics of cotton and polyester depends on their weaving properties, especially the type of weave such as plain and twill. 4) Polyester white fabrics with lower porosity than 5% have the higher UPF than 20. 5) The UPF is defined as a UV-B protection factor.
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  • Directional Controlling of Transmitted Light and Polarized Light Separation from a Monofilament Drawing Fiber Whose Cross-section is Triangle
    Kenro Totani, Hideki Hayashi, Hideki Hayashi, Toshiyuki Watanabe
    2008 Volume 64 Issue 7 Pages 171-177
    Published: July 10, 2008
    Released on J-STAGE: August 10, 2008
    DOIhttps://doi.org/10.2115/fiber.64.171
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    Control of light diffusion or direction of transmitted light were generated from polymer composites, consisting of single fiber and surrounded polymer matrix, using a fiber whose cross-section is triangle shape. Light diffusion property was drastically changed by following two ways, slight rotation of samples with respect to the direction of incident light, or little adjustment of refractive index of polymer matrix. If triangle fiber was used, spatial pattern of light diffusion was strongly dependent on incident light direction or refractive index ratio between fiber and polymer matrix, whereas, if circular fiber was used, they were relatively insensitive to incident light direction or refractive index ratio. In this research we also succeeded in polarization separation, by use of a monofilament birefringent fiber. The fabrication procedure was same except that fiber was birefringent. Since the light diffusion property was drastically influenced by the shift of refractive index, spatial patterns of light diffusion were quite different between two polarized light (axis of electric field are vertical each other) in birefringent fiber, thus polarized light was separated to different directions. In our samples, we could separate more than 95% of polarized light into two different directions.
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  • Electro-optical Response of Liquid Crystal Displays with Alignment Layers of a Cellulose Derivative
    Yasushi Kasajima, Takashi Kato, Atsushi Kubono, Shigeru Tasaka, Ryuich ...
    2008 Volume 64 Issue 7 Pages 178-180
    Published: July 10, 2008
    Released on J-STAGE: August 10, 2008
    DOIhttps://doi.org/10.2115/fiber.64.178
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    Low voltage operation and fast response of liquid crystal displays (LCDs) can be achieved by using a hybrid twisted nematic (HTN) cell, which is fabricated by applying the conventional twisted nematic (TN) cell. Unfortunately, the devices exhibit a narrow viewing-angle in the same order as that of TN. It has been reported that an alignment layer made of hydroxyl propyl cellulose (HPC) results in specific orientation; the director of the LC can be parallel to the substrate surface and random in the plane without any defects. The HTN cells with HPC as an alignment layer afford wide-viewing-angle as well as low voltage operation and fast electro-optical response.
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  • Drawing of Poly (L-lactide-co-ε-caprolactone) Monofilament under the Heating of Air-heater and/or Laser Irradiation
    Toshifumi Ikaga, Masanori Endo, Koji Kuroda, Yutaka Ohkoshi, Yasuo Got ...
    2008 Volume 64 Issue 7 Pages 181-186
    Published: July 10, 2008
    Released on J-STAGE: August 10, 2008
    DOIhttps://doi.org/10.2115/fiber.64.181
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    Poly (L-lactide-co-ε-caprolactone) monofilament was drawn with three ways of heating methods, those are air heater heating, CO2 laser irradiation, and laser irradiation after heater pre-heating. The mechanical properties and diameter deviation of the drawn filaments were analyzed. The lowest drawing stress and the least diameter deviation were obtained for the heating of laser irradiation after heater pre-heating. Moreover, only by the heating of laser irradiation after heater pre-heating, the drawing point could be fixed even for draw ratio of 4. And after the 3-step drawing, the filament which have the maximum strength of 651MPa was obtained by the heating method.
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  • Mobility of Water in a Hydrophobic Polymeric Matrix as a Model System for an Offset Printing Ink
    Kazunori Iwata, Shigeki Kuroki, Mitsuru Satoh
    2008 Volume 64 Issue 7 Pages 187-198
    Published: July 10, 2008
    Released on J-STAGE: August 10, 2008
    DOIhttps://doi.org/10.2115/fiber.64.187
    JOURNAL FREE ACCESS
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    As a fundamental research for elucidation of effects of "dampening water", which is added during the usual offset printing, on the printing performance, 1H-PFGStE NMR and T2 measurements were carried out to investigate the mobility of water in model ink systems consisting of a phenol resin and oil components. Only for crosslinked systems with an aluminum chelate or abietic acid, some of the water showed a "restricted diffusion", meaning that the water is distributed in a limited region of some micron size in the polymer matrix and the water movement is confined within the region.
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