Plastic Optical Fiber (abbreviate POF) is used in the various fields; short range communication, sensor, illuminate exploitation and so on. The fabric is one of the forms in illumination fields, but there are no reports about the lighting properties of POF fabrics. In addition, for the fabric development, it is very important to estimate the optical characteristic in the textile design stage.
In this report, the lighting properties of POF fabrics are measured and the new method to estimate the optical properties of POF fabric is suggested.

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In industrial materials, tribological properties of fibers are one of very important practical properties. To make high abrasion resistance fibers, Polypropylene/Polyamide 6 (hereafter “PP/PA6”) blend fibers of different blend ratios and viscosity ratios were prepared. The relationship between abrasion property and blend ratio of the blend fibers showed that the abrasion resistance increased by blending PA6 by about 20% compared with pure PP fiber, and that the abrasion resistance decreased as more PA6 was blended. Pure PA6 fiber (PA6 content=100%), however, showed a high abrasion resistance. Namely, the relationship between abrasion resistance and blend ratio of the blend fibers was shown in a reverse-S-shaped curve.
Then, abrasion property was studied for blend fibers of different viscosity ratios (η_PP/η_PA6). The results showed that the blend fiber of a viscosity ratio value smaller than 1 had relatively low abrasion resistance even for equivalent PA6 content, and that abrasion resistance increased as viscosity ratio increased. Investigation of the composition of the fiber surface by FTIR-ATR proved that as the abrasion resistance of the blend fiber increased, the content of the PA6 component on the surface increased. Blend fibers of viscosity ratio value more than 1 had considerable abraded powder on the fiber surface after abrasion, indicating further improvement of abrasion resistance. These results indicate that a blend fiber of a large viscosity ratio has a higher abrasion resistance than pure PA6 fiber and PP fiber.

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Nylon 6 fibers are used as tire cord in carcass of automobile tire for rubber reinforcement to keep internal pressure. During run state, the internal part of tire is heated up to 100 °C and cooled by stopping, resulting in the same thermal history of Nylon 6 tire cord. It has been reported that crystal phase of Nylon is transformed to other phase under high temperature condition. In room temperature, two reflection peaks assigned to α-phase were observed by wide angle X-ray diffraction measurement for Nylon 6 fiber. On heating, these two peaks became one peak of pseudohexagonal phase at around 70 °C. This transition referred as the Brill transition took place repeatedly by heating and cooling. Also, tensile strength decreased with increasing temperature by heating and increased by cooling. For higher-order structure measured by small angle X-ray scattering, the long period of Nylon 6 lamella was constant on cyclic temperature changes. On the other hand, it was observed that the slope against fiber direction and the size of lamella were irreversibly changed at around 70 °C. It has been reported in former study that the Brill transition was observed at higher temperature region than 150 °C because samples were Nylon 6 pellets and films. Accordingly, the Brill transition temperature changed much lower in high oriented Nylon 6 fiber.

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To obtain fundamental information on the washing feeling and the cleaning performance of washcloths, we surveyed the washing feeling using five kinds of washcloth on market in Japan, which were made of cotton, ramie, silk, regular synthetic fiber (nylon/polyester), and microfiber (nylon/polyester). Further, we selected the regular and microfiber washcloths for further study due to remarkable differences in washing feeling between them. We examined the performance of both types washcloth on cleaning a felt-tip-pen mark from human skin, their effect on stratum corneum, and made physical measurements of the contact state between them and human skin, etc. It was found that the regular washcloth had a poor cleaning effect, though it had a good washing feeling. On the contrary, the micorifiber washcloth had a good cleaning effect, though it had a bad washing feeling.

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The present study is concerned with numerical simulation of compressible air flow in a yarn duct of an interlacer and the relation between air flow and yarn entanglement. A nozzle of circular pipe of inner diameter d (< D) is mounted perpendicularly to the yarn duct of circular pipe of inner diameter D (d < D). The interlacer system is analyzed numerically using the high Reynolds number k-ε model. The dependence of compressible air flow on the ratio d/D is examined numerically and experimentally. When the average local Mach number at the entrance of the nozzle pipe reaches 0.5 ∼ 0.71, the flow chokes immediately after passing the nozzle pipe. The limited Mach number at the entrance of the nozzle pipe depends on the flow in the nozzle pipe, namely the friction loss. Furthermore the strength and the number of yarn entanglement vary with d/D and become maximums at d/D ≅ 0.5.

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Segmented polyurethane-urea (SPUU) is a block copolymer which consists of hard and soft segments. SPUU films with different ratios of ethylenediamine (EDA) and propylenediamine (PDA) as chain extenders were prepared. The values of two parameters of C₁ and higher order term Δh obtained by Mooney-Rivlin plots in the stress-strain relationship were estimated. It was clarified that these parameters had good relation with the aggregate structure of hard segments which were formed through hydrogen bonding. The higher order term Δh and hydrogen bond concentration of urea group measured by FT-IR decreased with increasing PDA content in hard segment. Infrared dichroism measurements revealed that hard segments showed peculiar orientation behaviors. Transverse orientations of hard segments occurred at initial state of elongation process, which were caused by orientation of long axis of the hard segment aggregate structures. The orientation of soft segments, however, was not affected by hard segment structures.

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