The samples used for this experiment were liquid soybean oil (I. V. 136.2) mixed with fully hardened soybean oil (I.V. 0.4) or fully hardened beef tallow (I.V. 0.3) by 10, 20, 40, 60 or 80%, The open capillary melting point was measured, as in the previous work, after standing at 0°, 10°, 20°, 40° or 50°C for 1, 5, 24, 120 and 1, 440 hr (2 months). At the same time, its correlation to polymorphism was examined, and the softening point (ring-ball type), Wiley melting point and slipping point were also investigated.
1) The open capillary melting point showed a great difference according to the temperature of standing when mixed with 10 or 20% of fully hardened oil, but the difference became smaller withincrease in the amount of hardened oil present.
2) The sample mixed with hardened soybean oil showed rapid transition, all becoming β-type after lhr, and there was no difference by the time and temperature of standing. Samples mixed with 1040% of hardened beef tallow became β-type in 1 hr, and were β′-3 type with 6080% mixture, : showing far more rapid transition than the solitary hardened beef tallow.
3) In all the samples, presence of a large amount of liquid oil resulted in indistinct pattern in X-ray diffraction because of the segregation. Since there was a difference in the melting point by the temperature of standing in spite of the absence of difference in polymorphism it was considered that in such a mixture of oppositely different substances progress of crystallization resulted in segregation, with separation of the solid and liquid parts, and the difference of crystal growth in the solid portion created a difference in the melting point.
4) Both the Wiley melting point and slipping point were higher than the open capillary melting point, and the difference was greater with increase in the amount of liquid oil present. In contrast, the softening point became lower with increase in the amount of liquid oil, but became higher than the open capillary melting point with increase in the amount of hardened oil and there was no definite correlation between them.
5) In general, the lower the temperature of standing and the greater the amount of liquid oil present the measured values became scattered. The scattering of the measured values became greater in the order of the Wiley melting point, softening point and open capillary melting point.
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