Mono filament melt spinning theory has been already established and widely used for computer simulation. In the industrial melt spinning process, however, the multi-filament melt spinning is performed.
One of the most important points in the multi-filament melt spinning is how to reduce irregularities between the filaments. To solve this problem, it will be necessary to establish the theory of multi-filament melt spinning and use it effectively.
In the multi-filament process, the cooling conditions must be described in terms of those of the ambient air surrounding each filament. Under several assumptions such as non-compressibility of air, the functions based on the heat and mass balances of cooling air were introduced. The wellknown Sakiadis' function for the air flow growing with running filament is not appropriate to use because it lacks the take-up speed dependence.
In the present study, linear relation between the above-mentioned air flow and the take-up speed was considered, and its coefficient was determined using the results of experiments and theory.
Applying these functions to the steady-state mono filament melt spinning theory, we established the steady-state multi-filament melt spinning theory.

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In this paper, filament unevenness are examined experimentally and theoretically using a simulation method developed by the authors. Oscillation data of filament finess, and those of spinning tension and cooling velocity of air, which measured on spin-line synchronized with filament finess, were statistically analyzed. The obtained result indicated that the direct corelation among three factors was scarcely observed. This fact was supported by the calculation of dynamic simulation. At the same time, small but distinct corelation was found among the finesses of four filaments simultaneously spun from the same spinneret. By the calculation of power spectrum, it was clarified that a characteristic periodical component introduced by the spinning condition was observed in filament evenness. This fact could be predicted by the simulational computation. From these results, it was concluded that the spectrum of filament unevenness consisted of two or three prominent waves having different frequencies, corresponding to the reciprocal of resident time and to that of integral multiples of spinning process.

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A high density polyethylene was subjected to the flat-film casting through a 20cm coathanger die coupled to a 25mm single screw extruder. A specially designed electrode, consisting of 26 needles vertically aligned on a surface of a thin aluminum strip at intervals of 2mm, was placed several centimeters apart under the coathanger die and connected to a high voltage direct current generator, while the chill-roller of the film processor being grounded so as to act as the counterelectrode. The molten running film emerged through the die at the linear velocity of 0.75m/min. was drawn down in the electrostatic field generated between these electrodes and immediately frozen on the chill-roller rotating at the surface velocity of 15m/min. The variation of the film width was measured as a function of the applied voltage and the film-to-electrode distance. When the applied voltage exceeded 4kV, the running film began to spread in width and to retract in thickness. The width increased drastically at the voltages ranging from 6kV to 18kV. Above 20kV it gradually levelled off to the value 1.4 times as wide as that at 0kV. On the other hand, the film width was almost independent of the film-to-electrode distance. The mechanism for spreading width was considered as follows: The corona shower from the electrode put the sufficient quantity of the electric charge on one side of the film surface and subsequently induced the corresponding charge of opposite sign on the surface of the chill-roller contacting to the other side of the film. The coulombic attractive force between these positive and negative charges might press the film in the direction of the film thickness and it consequently resulted in the spreading of the film in both longitudinal and transverse directions. The longitudinal contribution, however, probably reduced the draw-down tension because of the large draw-down ratio, whereas the transverse one might make the neck-down smaller. Finally it must be noted that the film thus prepared was very transparent and had a very clear surface.

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Chitosan films were prepared by several methods of casting from solution. Chitosan salts from formic acid, acetic acid and butyric acid were observed in the as-cast films from the each aqueous solution of chitosan salts. The unit cell parameters of crystals formed in each chitosan film were determined by the use of wide-angle x-ray diffraction.

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Studies on biological activity of d-empenthrin against textile pests were performed. d-Em-penthrin was found to have sufficient efficacy against casemaking clothes moth and black carpet beetle as a volatile insecticide at room temperature under closed conditions. A d-empenthrin mothproofer strip which contained 0.5gram of d-empenthrin on a 150cm² (10×15cm) filter paper could control textile pests in a wardrobe for more than 6 months. It was also indicated that small pieces (for example, 3×10cm, 3×3cm) of d-empenthrin mothproofer strip could control even in the chest of a drawer packed with clothes.

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The effect of pressure on the diffusion coefficient, D, of seven disperse dyes in nylon 6 sheet has been investigated. D was measured at 90°C with the multiple membrane placed in the aqueous solutions of the dyes under pressures up to 3kbar. The values of In D decreased linearly with increasing pressure, from which the activation volume, ΔV_??_, for the diffusion was estimated to be 20.2-33.2cm³/mol for the seven dyes. The ΔV_??_ values were compared with the intrinsic volumes, V_w's, of the dyes. It was found that ΔV_??_ increases almost linearly with increasing V_w for the series of the anthraquinone and azo dyes. It was also found that ΔV_??_for the anthraquinone dye is larger than that for the azo dye if they are compared at the same V_w. These findings are in accordance with those obtained previously for poly (ethylene terephthalate).
The results obtained above were discussed in terms of ΔV^_??__EH, ΔV^_??__W and ΔV^_??__i, where ΔV^_??__EH is the volume change on the formation of the Eyring's hole, ΔV^_??__W is the change in V_W on the activation and ΔV^_??__i is the volume change on the activation due to the _??_teraction of the penetrant dye with the surrounding swollen polymer matrix.

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Nylon 6 film and acrylic acid grafted nylon 6 membranes prepared by γ-irradiation method were reacted with paraformaldehyde and lactic acid in the presence of acid catalysts. Decrystallized nylon 6 (DN) and decrystallized grafted nylon 6 (DGN) membranes were thus obtained. The reverse osmosis properties of the membranes were investigated. The hydraulic permeability coefficient, K₁, of water increased with increasing the volume fraction of water in the swollen membranes. Although the salt rejection, R_s, decreased with increasing the volume fraction for DN and 50% grafted DGN membranes, this pattern was not observed for the DGN membranes with more than 100% grafting. For the latter membranes the salt rejection decreased only slightly even at higher K_l values. An equation to relate R_s to K₁ is described. For the parallel transport of pure water and salt solution with the same concentration of the feed solution through different parts of the swollen membranes, the salt rejection, R_s, can be represented as where k is the rate ratio of the volume flows in pure water and in the salt solution. V₁/V₀ represents the fraction of the volume of the pure water phase in the total membrane volume. B and K₀ are constants.

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