Congo red test
Laboratory > Ageing
| Congo Test | |
| Residual heat stability | |
The residual thermal stability of finished PVC articles is carried out by static heat testing by storing samples in a test furnace or by the dehydrochlorination method. One simplified method, very common in the cable industry, is the Congo Red Test (VDE 0472, part 614, ISO 182). For this test, the sample is cut into small pieces and heated in a test tube, the chloridic acid HCl, which is released, causes a color change of the Congo Red indicator or universal indicator, the indicator is a paper that is put in the upper part of the test tube. The time is measured from the insertion of the sample in the heating medium until the color change. |  |