This paper reports a study on the effects of fabric liquid water transfer behavior on human thermophysiological responses and clothing microclimate. Both cotton and polyester fabrics were treated to have different liquid water transfer properties. With moisture management (MM) treatment, the fabrics can transfer liquid water from inner surface (close to skin) to outer surface (close to surrounding environment) during wearing while keeping skin dry. With reversed moisture management (RMM) treatment, the inner layer of the fabric is water absorbency, liquid water is difficult to be transferred to outer surface. Two sets of garments were made of MM and RMM fabrics for both cotton and polyester respectively. A series of wear trials were conducted by asking human subjects to wear these garments according to a specially designed experimental protocol. The microclimate humidity and temperature, skin temperature and ear canal temperature were recorded. MM cotton garment caused significant lower absolute humidity outside clothing (H_co) during exercise and recovery, higher temperature outside clothing (T_co), higher mean skin temperature (T_sk) and lower ear canal temperature (T_{ear_canal}) during recovery than RMM cotton. Polyester MM garment caused significant higher Hco during exercise and higher T_sk than RMM polyester. For both cotton and polyester, MM garment is better than RMM garment to reduce heat stress during exercise and recovery in temperature of 30 °C and relative humidity of 30%.

View full abstract

Six kinds of subtropical plant fibers taken from the Hibiscus, Pineapple, Okra, Plantain, Banana and Agave were treated with sodium hydroxide aqueous solution and liquid ammonia using a commercial plant. Cross section of the fibers were observed with microscope. Furthermore, in order to investigate the internal structure, X-ray diffraction measurement was carried out and the crystallinity of the treated fibers was obtained. From the observation of the cross section, it is clear that every fiber forms honey comb structure which consists of several to many cells, and each cell has a void in the cell. The void is comparably larger than that of the cotton lumen, and the void generally became smaller by the NaOH treatment. Furthermore, X-ray diffraction profile was measured for each fiber. Most of the fibers were changed from cellulose I to cellulose II by the NaOH treatment, whereas the fibers unchanged to cellulose III by the NH₃ treatment. After the three times NH₃ treatment, the cellulose III intensity increased comparably, although the cellulose I remains not a little for all samples. On the other hand, cotton fiber completely changed to the cellulose III structure by the NH₃ treatment. Hereafter, it is necessary to investigate the void structure including the effect of lignin and cell-wall as a multicelluar plant fiber.

View full abstract

It is estimated that about tow million tons of used fiber are discharged annually in Japan. This situation has raised the concerns about the necessity to find innovative usage of used fibers and new recycling technologies. Therefore, various attempts have been carried out in our textile industry to construct the recycling-type society.
For example, compression molding system of lumber substitutive materials by using the fiber wastes as raw material is very interesting. In this molding process, the binder material such as thermoplastic fiber is used in order to bind the neighboring fiber wastes. It can be easily expected that the shape of melted binder remarkably affects on the mechanical properties of substitute lumber.
In this paper, the felt is pre-molded in which PP fibers with various sizes are added as a binding material. Then the felt turns to fiber board by the compression molding method under heating. The effects of binder shape to the bending properties of the fiber board are discussed.
As a result, it is clarified that the fiber sizes of PP binder remarkably affects on the shape of melted PP and also the bending properties of molded board.

View full abstract

Orientation and concentration distribution of fibers in a slit channel flow were experimentally studied for both dilute and concentrated fiber suspensions. First, the inner diameter of the conduit tube connected to the test channel was determined, because the concentration distribution of fibers in the conduit tube directly affects that in the test channel. As a result, the conduit tube having an inner diameter of 6 mm was selected for fiber of 1 mm long to prevent non-homogeneous concentration distribution in the test channel. Second, the fiber orientation in the test channel was examined. Almost all fibers aligned in the flow direction for the dilute suspension. On the other hand, the preferred direction of large number of fibers also aligned in the flow direction for the concentrated suspension, but the degree of alignment became worse than that for the dilute one. This is because the fibers cannot rotate freely owing to fiber-fiber interaction. However, a large velocity gradient improved the degree of alignment near the channel wall even for the concentrated suspension. Furthermore, it was confirmed that the concentration distribution is nearly uniform in the test channel when the conduit tube larger than 6 mm in inner diameter is used for fiber 1 mm long. From the detailed measurements, however, a local maximum of the concentration appeared beside the channel wall for the dilute suspension because the fiber-wall interaction occurred, while the concentration of fibers gradually and monotonously decreased as one approaches the channel wall for the concentrated suspension.

View full abstract

In general, acid dyes have high affinity toward nylon fibers, meaning that the dyes quickly bind with the polymer. Thus, if the dye is absorbed by the polymer too quickly, the nylon fibers can absorb the dye unevenly and not exhibit a constant shade or color. Consequently, nylon fibers are typically dyed with acid dyes under carefully controlled conditions in order to control the rate at which the dye is absorbed by the polymer. In particular, the temperature and the pH in the dye bath are usually monitored and regulated during the process. This article is focused on: 1. the relationship between different pH values and the exhaustion rates of metal complex dyes, 2. the relationship between different acids and the color strength of metal complex dyes, 3. the effect of pump flow on fabric running speed and level dyeing property. Our results showed that if the traditional acid agent was replaced with pH sliding agents, the critical dyeing range (C_R) would be changed from 30∼60 °C to 50∼60 °C, the final dyeing temperature (T₉₀) could be changed from 71 °C to 86∼95 °C and then level dyeing fabrics was obtained. Increased dyeing pump flow and nozzle pressure caused to increased running speed of the fabric and shortened time required for the dyeing process by 20 min. It can help saving energy and costs for the dyeing process.

View full abstract