An apparatus to evaluate UV shielding properties of fabrics is developed. The apparatus consists of three parts; light source, sample holder and photo sensor. Light source is UV LED of which peak wave length is 378 nm. Photo sensor is silicon photo diode. Using this apparatus, the effect of measurement condition, fiber material and fabric construction of fabrics on UV shielding property is investigated. The results obtained are as follows.
1. Distance between light source and sample does not affect UV transmittance, and UV transmittance decreases with increasing space between sample and sensor.
2. Results of investigation on the effect of fiber materials, fabric thickness and weight on UV transmittance are obtained as follows within the range of samples used here. As a whole, UV transmittance of fabrics made of synthetic fiber is large and that of fabrics made of natural fiber is small. UV transmittance decreases with increasing fabric thickness and weight. The result for thickness dependence can be regressed using exponential equation. UV protection performance per unit thickness of silk is high compared to other fibers.

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In order to make clear the air flow in the yarn duct, which has the maximum effect on the generation of interlaced yarns, the flow near to the yarn duct wall and the jet issuing from a circular air jet nozzle were measured in basic type interlacers with various diameters and lengths of yarn duct. The jet issuing from the air jet nozzle forms a detached shock wave in front of the yarn duct wall opposite to the air jet nozzle. After running against the yarn duct wall, the air forms two twin spiral eddies in the yarn duct. The diameter ratio of yarn duct to air jet nozzle has an effect on the jet width and the circumferential component of the flow velocity and hence it has a greater effect on the processability of interlaced yarns than the yarn duct length.

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The aim of this study is to clarify the dyeing behavior with acid dyes in the segmented polyurethanes with soft segments composed of various ratios of PTMG and PEG components by measuring the dye uptake. Experiments revealed that the higher ratio of PEG component resulted in increasing the hydrophilic property and decreasing the aggregate structure in the segmented polyurethanes. Aqueous dyeing solution, consequently, seemed to adsorb positively into the intra-molecules of polyurethanes.
Considering the stress-strain relations and water-swelling characteristics of polyurethane films, the dye affinities of the films before and after dyeing were evaluated. After dyeing, the segmented polyurethane films seemed to losing hydrogen-bonding ability resulting in making the aggregate structure small. It was suggested that the dyestuff molecules were adsorbed in the hard segments of the polymers with some form of bonding.
Furthermore, it was observed that the dye adsorption for CI Acid Red 114 was higher than that for CI Acid Red 37 among two kinds of acid dyes applied in this study. It was suggested as follows: (1) CI Acid Red 114 having bulky molecular structure against CI Acid Red 37, ca. 1.6 times in molecular weight, contributed to adsorb into the segmented polyurethanes with van der Waals forces. (2) CI Acid Red 114 molecule modified with formic acid in dyeing bath changing to insoluble form for water adsorbed easily onto the hydrophobic group of the segmented polyurethanes.

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Silkworm cocoons have been dyed using acid dyes (C. I. Acid Orange 7 and C. I. Acid Orange 63) while retaining their shape under various conditions, and the dyeing properties have been investigated for developing a new fiber technology. Whereas the corner of the cocoon shell was thin and could be dyed in shorter time, the center of the cocoon shell was thick and needed more time. The penetration depth of the dye molecule into the cocoon increased with time, but the penetration speed was not constant: the penetration rapidly increased within 5 minutes, but afterwards gradually increased. This result is due to the structural differences among the shell layer portions. In addition, when the dye bath was at a lower pH, the penetration speed was slightly slower. Moreover, the C. I. Acid Orange 63 molecule penetrated more slowly than the C. I. Acid Orange 7 molecule. These results are probably attributed to the difference in the adsorption state of the dye molecule on the fiber.

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