| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for evaluating deterioration of polyvinyl chloride for easily evaluating a state of deterioration without damaging the polyvinyl chloride resin. SOLUTION: Such a determination is made that the larger a measurement value indicating a hardness measured by a digital-display type hardness tester with the maximum spring load of not less than 29,000 mN is, the more highly the polyvinyl chloride resin is deteriorated. The hardness tester is used to measure the hardness of a sheet-like polyvinyl chloride resin while the resin is being tensioned, and a correlation line L1 between its tensile strength and hardness is obtained. The resin shows a higher hardness and a smaller elongation (%) as the degradation proceeds, as shown by a correlation line L2 between the hardness and elongation. The correlation line L2 has a very high correlational relationship with the correlation line L1. That is, the above specified hardness tester can measure a minute change of the hardness according to a change of tensile strength by gradually changing the strength so that an accurate measurement of states before and after the progress of deterioration can be measured. COPYRIGHT: (C)2004,JPO
|
