The physical properties of ethylene-vinylalcohol-acrylic acid terpolymer (EVA-AA) cross-linked with diamine were investigated in relation to thermal properties measured by DSC and dynamic mechanical properties.
The following results were obtained:
1) EVA-AA was cross-linked by a two-step process viz., the immersion into a diamine solution and heat treatment. The degree of cross-linking and the physical properties of cross-linked EVA-AA were affected by the degree of swelling at immersion and the conditions of heat treatment i.e., temperature and time.
2) As the degree of cross-linking increased, the glass transition temperature and flow-region shifted to a higher temperature level and obscured away.
3) Tensile properties of the cross-linked films had a tendency to deteriorate under profuse swelling in diamine solution causing a decrease of crystallinity and disarrangement of the molecular orientation.
4) The moisture regain of the cross-linked specimens was 8_??_13%.
The degree of shrinkage in boiling water and the degree of heat-shrinkage at 150°C of effectively cross-linked films were both less than 10%.

View full abstract

The compressive modulus and the handle “hardness” of multi-layer foams, which are made up of flexible polyurethane foams having different compression characteristics, were discussed.
The results obtained are as follows:
1) The compressive modulus Y_B of multi-layer foams can be calculated with the following equation. Where, l_i and Y_i are the thickness and the compressive modulus of foams which compose multi-layer foams.
Good agreement between the calculated values of Y_B and the measured ones is obtained.
2) The handle “hardness” of multi-layer foams depends on two physical properties. The one is the compressive modulus Y_B of multi-layer foams and the other is the compressive modulus Y_t of the top-layer foam in multi-layer foams.
By a discriminant function analysis, following equation is obtained. Z is discriminant function for the handle “hardness” of multi-layer foams.
The correlation coefficients between the values Z of discriminant function and subjective rating (hardness) S_h are 0.991 in two-layer foams, 0.975 in three-layer foams and 0.988 in four-layer foams.
3) From the equation of Z, it is seen that Y_B is more affecting to the handle “hardness” of multi-layer foams than Y_t.

View full abstract

The sliver was separated into small fiber assemblies using opening device with combing roller as well as air suction, and then the effects of sliver thickness, input roller speed, surface speed of combing roller, and air velocity on the weight of separated fiber assemblies were studied.
The sliver having periodic irregularity was separated, and the weights of fiber assemblies were detected and recorded continuously. The variations in their weight were statistically analysed into auto and cross correlation functions.
The results obtained are as follows:
(1) In the case of using both combing roller and air suction, the weights and their variations are smaller than when only air suction is used.
(2) The thicker the input sliver is, the greater the weight of separated fiber assemblies becomes. The surface speed of feed roller makes the same effect as the thickness of input sliver. (Fig. 3, Fig. 4)
(3) Though the surface speed of combing roller has little effect on the weight of separated fiber assembly, the velocity of suction air has greater effect on it. (Fig. 5, Fig. 6)
(4) Separating sliver generates the additional random variation on the output, so relatively the ratio of periodic variation to total variation decreases, especially by using opening device without combing roller works effectively. (Fig. 11)

View full abstract

The relation between pilling tendency and tensile properties of staple fiber was studied by rearranging and analysing a lot of data which had been carried out by trial and error.
Principal component analysis was used as a statistical analysis. It was found that pilling tendency by ICI-method (pill grade) is composed of three principal components as shown below.
Principal component No.1 is related to shear strength such as knot tenacity (KT), loop tenacity (LT) and loop elongation (LE), and its percentage of contribution to pilling tendency is found the largest.
Consequently, pilling tendency can be represented by a few tensile properties of staple fiber such as KT, LT and LE. Furthermore, rate constant of pill wearing-off (k₂) by SF-pill-tester shown in the previous report holds good correlation to principal component No.1.

View full abstract

The air flow around metallic wire on a carding cylinder was simulated by water flow around transparent plastic model wire of twenty times as large as the metallic wire with the same Reynold's number. Polystylene beads of 0.5_??_1.0mm dia. or aluminum flakes suspended in the water enabled the visualization of the velocity distribution at various section by means of photometry with a slit and a chopper.
Comparison between the velocity distribution obtained by the simulation test with the saw-toothed wire model and the distribution obtained by theoretical calculation with a flat wire model as shown in Fig. 6 shows that the drag was maximum at a layer between the tip and bottom of the saw-tooth.
From the comparison of these two kinds of velocity distribution, the velocity distribution by the simulation test was expressed by an experimental equation based on the distribution by theoretical calculation with a flat wire model. The ratio of drag-and-friction coefficient of the saw-toothed wire to that of flat wire model could also be obtained from these two distributions.

View full abstract

Melting point depression by methoxymethylation was studied for nylon 6. In the previous paper³⁾, it was pointed out that the melting of nylon 6 fibers methoxymethylated to different extents behaves like that of non-isomorphic random polycaproamide copolymers. The melting behaviors of highly amorphous nylon 6 methoxymethylated to different extents were investigated here by using the DSC measurements. The obtained relation between the melting temperature and the mole fraction, 1-X_A, of the methoxymethylated units in the range of 1-X_A<0.15 satisfies the modified Flory's equation proposed by the authors. At 1-X_A≈0.25, a transition of methoxymethylated nylon 6 from partially crystalline to perfect amorphous state was observed from the DSC curves. This result is also supported theoretically.

View full abstract