浸渍法PVC制品密度测试的问题分析

Analysis on problems occurred during determinating the density of PVC products by immersion method

分析了PVC制品密度测试方法——GB/T 1033.1—2008浸渍法中密度计算公式忽略悬挂丝浮力所导致的结果误差。经理论推导给出了正确的计算公式。提出采用增大样品浮力/悬挂丝浮力比值、密度计算公式中扣除悬挂丝浮力和批量样品密度测试减少悬挂丝浮力波动等办法,减少浸渍法PVC制品密度测试的误差。

A density calculation formula was given in the immersion method which was part of GB/ T 1033.1--2008 for determining the density of PVC products. However, the formula ignored the buoyancy of suspending wire and thus errors were produced. The errors were analyzed. Through theoretical derivation, a correct formula was given. It was proposed that some measures could reduce the errors of the immersion method, i. e. increasing the buoyancy ratio of sample/suspension wire, deducting the buoyancy of suspension wires in density calculation formula, and reducing the buoyancy fluctuation of suspension wires through batch sample determination.