硬質塩ビ成形材料の衝撃試験について

抄録

In order to be equipped with necessary resources for establishing the standard (JIS) of impact testing of rigid PVC compounds, the Charpy and Izod impact testing was carried out of eight kinds of rigid PVC compounds by various testing methods, i. e., JIS K 6745, ISO R 179 and ASTM D 256. The test specimens were machined from the compression moulding plates of 4mm in thickness, which were made according to ISO R 293. The results obtained are summarized as follows
(1) There are roughly proportional relations between any two of the various impact strengths obtained from different compounds, i. e., the ratio ss·ISO·a_kC/JIS·a_kC takes roughly a constant value of a little less than 0.4, the ratio ss(e) ISO·a_kC/JIS·a_kC of about 0, 3, the ratio S·ISO·a_kC/JIS·a_kC of a little over 0.4, and the ratio ASTM·a_kI/JIS·a_kC of about 0.7, where JIS·a_kC, ss·ISO·a_kC, ss(e)·ISO·a_kC and S·ISO·a_kC represent Charpy impact strengths measured by JIS, standard small ISO, standard small ISO (Edgewise notch) and standard ISO Charpy impact test specimens respectively, and ASTM·a_kI is Izod impact strength by ASTM specimen.
(2) To insure effective discrimination among the impact resistances of compounds, shallower notch in the shape of Charpy impact specimen, as in JIS specimen, is preferable to deeper notch as in ISO specimen.
(3) It is found that there remain some problems to be solved, i. e., the influence of blow energy (Capacity of pendulum hammer) on the absorbed energy or on the fracture form, and no separation of fractured specimen into two halves etc., in the impact testing of modified PVC compounds such as high impact PVC compounds.