The dyeing method of polypropylene fibers applied reduction and oxidation of a cationic dye was investigated by using several dyes having phenyl phenazium, acridinium or oxazinium skeleton. Especially for dyes with phenoxazinium skeleton, Basic Blue 3 derivatives having different amino groups (dimethyl amino,diethyl amino, dipropyl amino, and dibutyl amino), counter anions (chloride, bromide, iodide, hydrogensulfite,and nitrate), and chalcogen elements (S and Se) were synthesized, and the effect of differences in their molecular structures on the dyeability was investigated. As a result, the effectiveness of dyes having the above skeleton for this dyeing method was confirmed. Moreover, the results showed that elimination and decomposition of substituents, hydrophobicity and bulkiness of the dye also affect the dyeability.
Black fabrics with different surface textures generated from the weave structure and yarn type were selected to examine how viewing distance affects changes in impression. Participants evaluated 16 fabrics draped over the spherical stand from a distance of 150 cm, then evaluated their visual-only and visual—tactile impressions from a distance of 15 cm. Semantic differential scaling of ±3 points for 12 bipolar adjective pairs word were used. It was found that the fabric impression of transparency and gloss were influenced by the viewing distance. When the gloss was perceived at 150 cm, the impression did not change at the shorter distance for samples F8 (shantung) and F15 (lawn). Regarding aesthetic components such as beautiful, like was perceived more visually at 150 cm than with a visual—tactile evaluation at 15 cm. The mechanical and surface properties of the fabrics were measured using the KES-FB system. An obvious change in perception of hardness/softness between two viewing distance were observed for samples with low bending rigidity. Surface morphology characteristics such as surface roughness (SMD) and mean deviation of surface friction (MMD) and air resistance are useful parameters for understanding the changes in impression according to viewing distance.
High stereoregularity isotactic polypropylene (iPP) can now be synthesized even using metallocene catalysts. Fibers with higher tensile strength than those of Ziegler-Natta catalyst-synthesized iPP have been reported for iPP with 20 g/10 min melt index. The aim of this study is to further increase the tensile strength using 4 g/10 min melt index iPP. Metallocene iPP fibers with higher tensile strength, higher initial modulus,and lower creep strain at 125 ̊C than Ziegler-Natta iPP fibers were also obtained using 4 g/10 min melt index iPP. Moreover, the obtained maximum tensile strength of 1.39 N/tex (1.3 GPa) was higher than that of 20 g/10 min melt index iPP. The metallocene iPP fibers also had smaller crack diameters estimated by ultra-small angle X-ray scattering.
Clothing pressure is one of the most important factors in clothing design as it is closely related to the wearing comfort of a garment. Although a few examples of estimating clothing pressure via simulation have been reported so far, the calculations are often difficult since clothing simulation is a non-linear analysis. Therefore, this study proposes a convenient method for estimating clothing pressure by combining a generic apparel computer aided design (CAD) program and finite element analysis software. In the first step, the three-dimensional (3D) shape of the clothing is acquired from its pattern using an apparel CAD program. Then, with the 3D shape of the clothing as the initial shape, a finite element analysis is conducted to calculate the contact between the human body and the clothing using the stress and strain arising in the cloth when it is worn as the loading conditions. Finally, the clothing pressure is computed as the pressure at the contact surface between the clothing and the human body. To validate the proposed method, the clothing pressures of two types of underwear-type compression wear were measured while draped on a torso. When compared to the actual measured values, the average error of the proposed method was 0.24 kPa and the correlation was r = 0.83. These results confirm that the proposed method can estimate clothing pressure with a reasonable degree of accuracy.