スクリュー押出装置による熔融ポリエチレンの粘度測定

抄録

To know the flow characteristics of molten plastics is very important for the study and the practice of extrusion of the like materials. In the present research work, the flow characteristics of polyethylene (Eastman, molecular weight=23000) were obtained for the temperature from 160° to 200°C with a small screw extruding apparatus. The pressure was calculated from the strain of tension bar by means of a strain meter. The rate of flow was also measured. Thus, the correlation between the rate of flow and the pressure was obtained, according to which three flow constants in the theological equation¹⁾
were calculated by the Sakurada-Sone method⁵⁾ as shown in Table 1.
The merits of this method of viscosity measurement with the screw extruding apparatus are as follow:
1. Uniform heating and kneading effect are obtained by the stirring motion of the screw.
2. Continuous measurement is possibte and feed and change of test material are very easy.
3. Change of piston velocity which occurs in the "piston and cylinder" apparatus can be avoided.